fibrin and Hemorrhage

Platelets play a central role in the arrest of bleeding. The ability of platelets to engage with extracellular matrix proteins of the subendothelium has long been recognized as a pivotal platelet attribute, underpinning adequate hemostasis. The propensity of platelets to rapidly bind and functionally respond to collagen was one of the earliest documented events in platelet biology. The receptor primarily responsible for mediating platelet/collagen responses was identified as glycoprotein (GP) VI and successfully cloned in 1999. Since that time, this receptor has held the attention of many research groups, and through these efforts, we now have an excellent understanding of the roles of GPVI as a platelet- and megakaryocyte-specific adheso-signaling receptor in platelet biology. GPVI is considered a viable antithrombotic target, as data obtained from groups across the world is consistent with GPVI being less involved in physiological hemostatic processes but participating in arterial thrombosis. This review will highlight the key aspects of GPVI contributions to platelet biology and concentrate on the interaction with recently identified ligands, with a focus on fibrin and fibrinogen, discussing the role of these interactions in the growth and stability of thrombi. We will also discuss important therapeutic developments that target GPVI to modulate platelet function while minimizing bleeding outcomes.

Topics: Blood Platelets; Collagen; Fibrin; Hemorrhage; Humans; Platelet Activation; Platelet Membrane Glycoproteins; Thrombosis

Fibrin polymerization is essential for stable clot formation in trauma, and hypofibrinogenemia reduces hemostasis in trauma. This review considers fibrinogen biology, the changes that fibrinogen undergoes after major trauma, and current evidence for lab testing and treatment.. Fibrinogen is a polypeptide that is converted to fibrin by the action of thrombin. During trauma, fibrinogen levels are consumed and reduce within the first few hours because of consumption, dilution, and fibrinolysis. Fibrinogen levels usually rebound within 48 hours of injury and can contribute to thrombotic events. The Clauss fibrinogen assay is the gold standard test for fibrinogen levels, although viscoelastic hemostatic assays are often used when a lab delay is anticipated. An evidence-based threshold for fibrinogen replacement is not well established in the literature, but expert opinion recommends maintaining a level above 150 mg/dl.. Hypofibrinogenemia is an important cause of nonanatomic bleeding in trauma. Despite multiple pathologic causes, the cornerstone of treatment remains fibrinogen replacement with cryoprecipitate or fibrinogen concentrates.

Topics: Afibrinogenemia; Fibrin; Fibrinogen; Hemorrhage; Hemostasis; Hemostatics; Humans

The multiple roles of red blood cells (RBCs) are often neglected as contributors in hemostasis and thrombosis. Proactive opportunities to increase RBC numbers, either acutely or subacutely in the case of iron deficiency, are critical as RBCs are the cellular elements that initiate hemostasis together with platelets and stabilize fibrin and clot structure. RBCs also possess several functional properties to assist hemostasis: releasing platelet agonists, promoting shear force-induced von Willebrand factor unfolding, procoagulant capacity, and binding to fibrin. Additionally, blood clot contraction is important to compress RBCs to form a tightly packed array of polyhedrocytes, making an impermeable seal for hemostasis. All these functions are important for patients having intrinsically poor capacity to cease bleeds (ie, hemostatic disorders) but, conversely, can also play a role in thrombosis if these RBC-mediated reactions overshoot. One acquired example of bleeding with anemia is in patients treated with anticoagulants and/or antithrombotic medication because upon initiation of these drugs, baseline anemia doubles the risk of bleeding complications and mortality. Also, anemia is a risk factor for reoccurring gastrointestinal and urogenital bleeds, pregnancy, and delivery complications. This review summarizes the clinically relevant properties and profiles of RBCs at various steps of platelet adhesion, aggregation, thrombin generation, and fibrin formation, including both structural and functional elements. Regarding patient blood management guidelines, they support minimizing transfusions, but this approach does not deal with severe inherited and acquired bleeding disorders where a poor hemostatic propensity is exacerbated by limited RBC availability, for which future guidance will be needed.

Topics: Anemia; Blood Platelets; Erythrocytes; Fibrin; Hemorrhage; Hemostasis; Humans; Thrombosis

Hemostasis is a complex and tightly regulated system that attempts to maintain a homeostatic balance to permit normal blood flow, without bleeding or thrombosis. Hemostasis reflects the subtle balance between procoagulant and anticoagulant factors in the pathways of primary hemostasis, secondary hemostasis, and fibrinolysis. The major components in this interplay include the vascular endothelium, platelets, coagulation factors, and fibrinolytic factors. After vessel wall injury, the subendothelium is exposed to the blood stream, followed by rapid activation of platelets via collagen binding and von Willebrand factor-mediated platelet adhesion to the damaged vessel wall through platelet glycoprotein receptor Ib/IX/V. Activated platelets change their shape, release bioactive molecules from their granules, and expose negatively charged phospholipids on their surface. For a proper function of this process, an adequate number of functional platelets are required. Subsequently, a rapid generation of sufficient amounts of thrombin begins; followed by activation of the coagulation system and its coagulation factors (secondary hemostasis), generating fibrin that consolidates the platelet plug. To maintain equilibrium between coagulation and anticoagulation, the naturally occurring anticoagulants such as protein C, protein S, and antithrombin keep this process in balance. Deficiencies (inherited or acquired) at any level of this fine-tuned system result in pathologic bleedings or increased hypercoagulability states leading to thrombosis. This review will focus on genetic diagnosis of inherited bleeding, thrombotic, and platelet disorders, discussing strengths and limitations of existing diagnostic settings and genetic tools and highlight some important considerations necessary for clinical application.. Die Hämostase ist ein komplexes und streng reguliertes System, das dazu dient ein homöostatisches Gleichgewicht aufrecht zu erhalten und einen normalen Blutfluss ohne Blutungen oder Thrombosen zu ermöglichen. Die Hämostase stellt das fein balancierte Gleichgewicht zwischen gerinnungsfördernden und gerinnungshemmenden Faktoren in der primären Hämostase, der sekundären Hämostase und der Fibrinolyse dar. Zu den wichtigsten Komponenten in diesem Zusammenspiel gehören das Gefäßendothel, die Thrombozyten, die Gerinnungsfaktoren und die fibrinolytischen Faktoren. Nach einer Verletzung der Gefäßwand wird das Subendothel dem Blutstrom ausgesetzt, gefolgt von einer raschen Aktivierung der Thrombozyten durch Kollagenbindung und VWF-vermittelte Thrombozytenadhäsion an der beschädigten Gefäßwand durch den Thrombozyten-Glykoproteinrezeptor Ib/IX/V. Aktivierte Thrombozyten verändern ihre Form, setzen bioaktive Moleküle aus ihren Granula frei und legen negativ geladene Phospholipide auf ihrer Oberfläche frei. Dieser Prozessder primären Hämostase setzt eine ausreichende Anzahl funktionstüchtiger Thrombozyten voraus. Anschließend beginnt eine rasche Bildung großer Mengen von Thrombin, gefolgt von einer Aktivierung der prokoagulatorischen Gerinnungsfaktoren (sekundäre Hämostase), wodurch Fibrin entsteht, das den initialen Thrombozytenpfropf verfestigt. Um das Gleichgewicht zwischen Gerinnung und Antikoagulation aufrechtzuerhalten, halten die natürlich vorkommenden Antikoagulanzien wie Protein C, Protein S und Antithrombin diesen Prozess im Gleichgewicht. Defizite (vererbt oder erworben) auf irgendeiner Ebene dieses so fein abgestimmten Systems führen zu pathologischen Blutungen oder einer erhöhten Hyperkoagulabilität, die zu Thrombosen führt. Diese Übersichtsarbeit fokussiert die genetische Diagnose von vererbten Blutungs-, Thrombose- und Thrombozytenstörungen, wobei die Stärken und Limitationen bestehender diagnostischer Verfahren und genetischer Techniken erörtert und wichtige Überlegungen für die klinische Anwendung gegeben werden.

Topics: Anticoagulants; Antithrombins; Blood Coagulation Factors; Blood Platelet Disorders; Blood Platelets; Collagen; Fibrin; Hemorrhage; Hemostasis; Humans; Phospholipids; Platelet Membrane Glycoproteins; Protein C; Protein S; Thrombin; Thrombosis; von Willebrand Factor

Ranging from bleeding to thrombosis, the clinical features of congenital fibrinogen qualitative disorders, including dysfibrinogenemia and hypodysfibrinogenemia, are highly heterogeneous. Although the associations between some specific fibrinogen mutations and the thrombotic phenotypes have been well elucidated, the underlying mechanism between fibrinogen variants and bleeding events remains underestimated. After systematically reviewing the literature of (hypo-)dysfibrinogenemia patients with bleeding phenotypes, we identified several well-characterized bleeding-related fibrinogen variants in those patients. Several possible pathomechanisms are proposed to explain the genotype-phenotype associations: 1, mutations in the NH

Topics: Afibrinogenemia; Blood Coagulation Tests; Fibrin; Fibrinogen; Fibrinogens, Abnormal; Hemorrhage; Humans; Thrombosis

Coagulation is a potential defense mechanism that involves activating a series of zymogens to convert soluble fibrinogen to insoluble fibrin clots to prevent bleeding and hemorrhagic complications. To prevent the extra formation and diffusion of clots, the counterbalance inhibitory mechanism is activated at levels of the coagulation pathway. Contrariwise, this system can evade normal control due to either inherited or acquired defects or aging which leads to unusual clots formation. The abnormal formations and deposition of excess fibrin trigger serious arterial and cardiovascular diseases. Although heparin and heparin-based anticoagulants are a widely prescribed class of anticoagulants, the clinical use of heparin has limitations due to the unpredictable anticoagulation, risk of bleeding, and other complications. Hence, significant interest has been established over the years to investigate alternative therapeutic anticoagulants from natural sources, especially from marine sources with good safety and potency due to their unique chemical structure and biological activity. This review summarizes the coagulation cascade and potential macromolecular anticoagulants derived from marine flora and fauna.

Topics: Anticoagulants; Enzyme Precursors; Fibrin; Fibrinogen; Hemorrhage; Heparin; Humans; Thrombosis

The formation of a fibrin clot matrix plays a critical role in promoting hemostasis and wound healing. Fibrin dynamics can become disadvantageous in the formation of aberrant thrombus development. Structural characteristics of clots, such as fiber diameter, clot density, stiffness, or permeability, can determine overall clot integrity and functional characteristics that have implications on coagulation and fibrinolysis. This review examines known factors that contribute to changes in clot structure and the presence of structural clot changes in various disease states. These insights provide valuable information in forming therapeutic strategies for disease states where alterations in clot structure are observed. Additionally, the implications of structural changes in clot networks on bleeding and thrombus development in terms of disease states and clinical outcomes are also examined in this review.

Topics: Fibrin; Fibrinolysis; Hemorrhage; Humans; Thrombosis

The COVID-19 pandemic has become an urgent issue in every country. Based on recent reports, the most severely ill patients present with coagulopathy, and disseminated intravascular coagulation (DIC)-like massive intravascular clot formation is frequently seen in this cohort. Therefore, coagulation tests may be considered useful to discriminate severe cases of COVID-19. The clinical presentation of COVID-19-associated coagulopathy is organ dysfunction primarily, whereas hemorrhagic events are less frequent. Changes in hemostatic biomarkers represented by increase in D-dimer and fibrin/fibrinogen degradation products indicate the essence of coagulopathy is massive fibrin formation. In comparison with bacterial-sepsis-associated coagulopathy/DIC, prolongation of prothrombin time, and activated partial thromboplastin time, and decrease in antithrombin activity is less frequent and thrombocytopenia is relatively uncommon in COVID-19. The mechanisms of the coagulopathy are not fully elucidated, however. It is speculated that the dysregulated immune responses orchestrated by inflammatory cytokines, lymphocyte cell death, hypoxia, and endothelial damage are involved. Bleeding tendency is uncommon, but the incidence of thrombosis in COVID-19 and the adequacy of current recommendations regarding standard venous thromboembolic dosing are uncertain.

Topics: Anticoagulants; Blood Coagulation; Blood Coagulation Disorders; Blood Coagulation Tests; COVID-19; Cytokines; Disseminated Intravascular Coagulation; Fibrin; Fibrin Fibrinogen Degradation Products; Fibrinogen; Fibrinolysis; Hemorrhage; Hemostasis; Humans; Inflammation; Lung; Lymphocytes; Partial Thromboplastin Time; Protease Inhibitors; Prothrombin Time; Sepsis; Thrombosis

Fibrinogen is a hexameric plasmatic glycoprotein composed of pairs of three chains (Aα, Bβ, and γ), which play an essential role in hemostasis. Conversion of fibrinogen to insoluble polymer fibrin gives structural stability, strength, and adhesive surfaces for growing blood clots. Equally important, the exposure of its non-substrate thrombin-binding sites after fibrin clot formation promotes antithrombotic properties. Fibrinogen and fibrin have a major role in multiple biological processes in addition to hemostasis and thrombosis, i.e., fibrinolysis (during which the fibrin clot is broken down), matrix physiology (by interacting with factor XIII, plasminogen, vitronectin, and fibronectin), wound healing, inflammation, infection, cell interaction, angiogenesis, tumour growth, and metastasis. Congenital fibrinogen deficiencies are rare bleeding disorders, characterized by extensive genetic heterogeneity in all the three genes:

Topics: Afibrinogenemia; Blood Coagulation Tests; Factor XIII; Fibrin; Fibrinogen; Fibrinolysis; Hemorrhage; Hemostasis; Hemostatics; Humans; Phenotype; Thrombosis

As our knowledge of the structure and functions of fibrinogen and fibrin has increased tremendously, several key findings have given some people a superficial impression that the biological and clinical significance of these clotting proteins may be less than earlier thought. Most strikingly, studies of fibrinogen knockout mice demonstrated that many of these mice survive to weaning and beyond, suggesting that fibrin(ogen) may not be entirely necessary. Humans with afibrinogenemia also survive. Furthermore, in recent years, the major emphasis in the treatment of arterial thrombosis has been on inhibition of platelets, rather than fibrin. In contrast to the initially apparent conclusions from these results, it has become increasingly clear that fibrin is essential for hemostasis; is a key factor in thrombosis; and plays an important biological role in infection, inflammation, immunology, and wound healing. In addition, fibrinogen replacement therapy has become a preferred, major treatment for severe bleeding in trauma and surgery. Finally, fibrin is a unique biomaterial and is used as a sealant or glue, a matrix for cells, a scaffold for tissue engineering, and a carrier and/or a vector for targeted drug delivery.

Topics: Animals; Fibrin; Fibrinogen; Hemorrhage; Hemostasis; Humans; Infections; Inflammation; Mice; Mice, Knockout; Wound Healing; Wounds and Injuries

The hemostatic balance in patients with liver diseases is relatively well preserved due to concomitant alterations in pro- and antihemostatic pathways. Thrombin generation studies support the notion of hemostatic competence in liver diseases, but in such tests alterations in fibrinogen level and function are not taken into account. We have recently studied structural and functional properties of the fibrin clot in patients with liver diseases. Although we have confirmed previous findings that hypersialylation of the fibrinogen molecule in patients with liver diseases contributes to a defective fibrinogen-to-fibrin conversion, we have found that once the clot has been formed, it has a thrombogenic nature as assessed by permeability assays. These thrombogenic properties of the fibrin clot in cirrhosis relate to incompletely characterized intrinsic changes in the fibrinogen molecule, which may include oxidation and hypersialylation. In addition, in patients with nonalcoholic fatty liver disease thrombogenic properties of the fibrin clot are not only due to liver disease but also to obesity and the metabolic syndrome. During liver transplantation, the clot normalizes and becomes increasingly permeable, and the functional properties of the fibrin clot are markedly normalized by fibrinogen concentrate, when added to plasma samples in vitro. These new insights in the functional properties of the fibrin clot in patients with liver diseases facilitate a more rational approach to treatment and prevention of both bleeding and thrombotic complications.

Topics: Fibrin; Fibrinogen; Hemorrhage; Humans; Liver Cirrhosis; Protein Processing, Post-Translational; Thrombosis

Fibrin formed from fibrinogen is the main component of thrombi. Clot structure is characterized by fiber thickness and pore size, which differs within a given clot and between individuals. Plasma clot architecture is largely determined by the quantity and quality of fibrinogen. Plasma fibrinogen concentrations are most commonly measured in citrated plasma using the Clauss method. However, several factors, including instrument type and reagent, may affect results. Other approaches to express the ability of fibrinogen to clot involve prothrombin time-derived or clottable protein assays, while fibrinogen antigen levels in clinical settings are measured using immunological or precipitation assays. Fibrin clot permeability (reflected by the Darcy constant, K s) being proportional to a buffer volume percolating through a clot under a given hydrostatic pressure is now the most commonly used measure of clot structure. Low K s values indicating tightly packed fibrin structure have been shown to be associated with venous and arterial thrombotic complications, while high K s might contribute to bleeding disorders. The measurement of K s, however, is not standardized and validated. This review summarizes the current knowledge on practical aspects of the measurement of fibrinogen levels and K s in patients.

Topics: Fibrin; Fibrinogen; Hemorrhage; Humans; Prothrombin Time

The structure and function of the blood clot has been associated with altered risk of thrombosis. Dense fibrin structures with small pores increase the risk of thrombosis, and have major functional consequences by increasing the resistance to fibrinolysis and altering the visco-elastic properties of the clot. However, while the structural changes to the overall fibrin network have been extensively characterised, little is known regarding the intrafibrillar structure of fibrin, the way protofibrils are arranged inside the fibrin fibers and the functional consequences of this. This brief paper aims to review recent findings regarding novel mechanisms that regulate fibrin intrafibrillar structure, including the degree of protofibril packing, their functional consequences, and the effects of FXIII activation on clot structure and thrombosis. It is concluded that fibrin intrafibrillar structure represents a major novel mechanism that influences clot structure and stability. Future studies are required to investigate the role of fibrin intrafibrillar structure in the functional characteristics of the blood clot, and in diseases of bleeding and thrombosis.

Topics: Animals; Blood Coagulation; Factor XIII; Fibrin; Fibrinogen; Hemorrhage; Humans; Thrombosis

Coagulation is a complex cascade whose intact functioning is essential in helping control hemorrhage after injury. While traditionally ascribed to the combined effects of acidosis, hypothermia, factor consumption and factor dilution, coagulopathy is also directly related to injury as well as hypofibrinogenemia and hyperfibrinolysis. Low fibrinogen concentration is readily determined with standard laboratory profiling, but direct analysis of hyperfibrinolysis relies on either thromboelastography or rotational thromboelastometry. Both conditions offer opportunities for therapeutic intervention, and inhibition or abrogation of hyperfibrinolysis in particular may significantly improve survival in patients with injury and massive hemorrhage. Herein, we explore the underpinnings of trauma associated coagulopathy, the basic science behind the role of fibrinogen in acute traumatic coagulopathy, and the rationale behind and the data derived from management of hypofibrinogenemia as well as hyperfibrinolysis.

Topics: Afibrinogenemia; Animals; Antifibrinolytic Agents; Blood Component Transfusion; Fibrin; Fibrinogen; Fibrinolysis; Hemorrhage; Hemostasis; Hemostatic Techniques; Humans; Multicenter Studies as Topic; Plasma; Randomized Controlled Trials as Topic; Tranexamic Acid; Wounds and Injuries

Within Canada, 2.6 million in-hospital surgical procedures are completed annually. Significant bleeding following is the most common surgical complication, occurring in up to 25% of all surgeries. Bleeding causes increased mortality and morbidity, by increasing the number of transfusions required, secondary to increased cumulative blood loss, and by causing hemodynamic instability. A solution to this issue encountered during surgery is the use of hemostatic products. The objectives of this manuscript are (1) to review the spectrum of hemostatic products available in cardiovascular surgery and (2) to provide an update on new topical products soon available, or in development, for optimizing hemostasis during surgical procedures.

Topics: Blood Loss, Surgical; Blood Transfusion; Canada; Cardiac Surgical Procedures; Chitin; Chitosan; Collagen; Cyanoacrylates; Fibrin; Hemodynamics; Hemorrhage; Hemostasis; Hemostatics; Humans; Polysaccharides; Thrombin

Although mortality rates from coronary heart disease in the western countries have declined in the last few decades, morbidity caused by this disease is increasing and a substantial number of patients still suffer acute coronary syndrome (ACS) and sudden cardiac death. Acute coronary syndrome occurs as a result of myocardial ischaemia and its manifestations include acute myocardial infarction and unstable angina. Culprit plaque morphology in these patients varies from thrombosis with or without coronary occlusion to sudden narrowing of the lumen from intraplaque haemorrhage. The coronary artery plaque morphologies primarily responsible for thrombosis are plaque rupture, and plaque erosion, with plaque rupture being the most common cause of acute myocardial infarction, especially in men. Autopsy data demonstrate that women <50 years of age more frequently have erosion, whereas in older women, the frequency of rupture increases with each decade. Ruptured plaques are associated with positive (expansive) remodelling and characterized by a large necrotic core and a thin fibrous cap that is disrupted and infiltrated by foamy macrophages. Plaque erosion lesions are often negatively remodelled with the plaque itself being rich in smooth muscle cells and proteoglycans with minimal to absence of inflammation. Plaque haemorrhage may expand the plaque rapidly, leading to the development of unstable angina. Plaque haemorrhage may occur from plaque rupture (fissure) or from neovascularization (angiogenesis). Atherosclerosis is now recognized as an inflammatory disease with macrophages and T-lymphocytes playing a dominant role. Recently at least two subtypes of macrophages have been identified. M1 is a pro-inflammatory macrophage while M2 seems to play a role in dampening inflammation and promoting tissue repair. A third type of macrophage, termed by us as haemoglobin associated macrophage or M(Hb) which is observed at site of haemorrhage also can be demonstrated in human atherosclerosis. In order to further our understanding of the specific biological events which trigger plaque instability and as well as to monitor the effects of novel anti-atherosclerotic therapies newer imaging modalities in vivo are needed.

Topics: Acute Coronary Syndrome; Cardiac Imaging Techniques; Chronic Disease; Coronary Artery Disease; Coronary Thrombosis; Female; Fibrin; Hemorrhage; Humans; Macrophages; Male; Necrosis; Plaque, Atherosclerotic; Platelet Aggregation; Risk Factors; Rupture, Spontaneous; Vascular Calcification

Acquired factor XIII (FXIII) deficiency, arising from an autoantibody against factor XIII, is a rare bleeding disorder. This autoimmune disorder most commonly occurs in the elderly. Patients who develop such acquired FXIII inhibitors may present with catastrophic bleeding events and are hard to be diagnosed with the normal general coagulation tests. Though the disease is relatively rare, it is known to cause significant mortality. In this article we briefly describe a patient who presented with extensive bleeding and a normal activated partial thromboplastin time and prothrombin time (PT), but had an acquired inhibitor to FXIII; her primary disease was systemic lupus erythematosus (SLE). Also, we will focus on the clinical features, treatment modalities, fibrin structure and epitope identification for acquired factor XIII inhibitor with a review of the literature.

Topics: Adult; Blood Coagulation Disorders; Blood Coagulation Factor Inhibitors; Epitopes; Factor VIII; Factor XIII Deficiency; Female; Fibrin; Hemorrhage; Hemorrhagic Disorders; Humans; Immunosuppressive Agents; Lupus Erythematosus, Systemic

Direct fibrinolytics are proteolytic enzymes that degrade fibrin without requiring an intermediate step of plasminogen activation. This review summarizes the current information available for five such agents, namely, plasmin (the prototypical form), three derivatives of plasmin (mini-plasmin, micro-plasmin, and delta-plasmin), and alfimeprase, a recombinant variant of a snake venom alpha-fibrinogenase, fibrolase. Biochemical attributes of molecular size, fibrin binding and inhibitor neutralization are compared. Preclinical investigations that assess the potential for thrombolytic efficacy in vitro and in animal models of vascular occlusion and for hemostatic safety in animal models of bleeding are detailed. Clinical potential has been assessed in patients with peripheral arterial and graft occlusion, acute ischemic stroke, and access catheter and hemodialysis shunt occlusions. The direct fibrinolytic agents have impressive biochemical and preclinical foundations for ultimate clinical application. However, clinical trial results for micro-plasmin and alfimeprase have not measured up to their anticipated benefit. Plasmin has thus far shown encouraging hemostatic safety, but efficacy data await completion of clinical trials. Whether direct fibrinolytics will provide clinical superiority in major thrombotic disorders over currently utilized indirect fibrinolytics such as tissue plasminogen activator remains to be determined.

Topics: Animals; Cardiovascular Diseases; Disease Models, Animal; Fibrin; Fibrinolysin; Fibrinolysis; Fibrinolytic Agents; Hemorrhage; Humans; Metalloendopeptidases; Peptide Fragments; Thrombolytic Therapy

A variety of local haemostatic agents is now available to stop troublesome bleeding. These agents are indicated for use during surgical interventions where conventional methods of haemostasis are not applicable because of the site of surgery or the degree of bleeding.. A literature search using the PubMed and ISI Web of Knowledge databases identified relevant studies on topical haemostatic agents. Manufacturers' recommendations were also sought through commercial websites.. A significant body of evidence now exists to support the use of topical haemostatic agents in a wide variety of clinical situations. The advantages and disadvantages of many of these agents are highlighted.

Topics: Administration, Topical; Albumins; Cellulose; Collagen; Drug Delivery Systems; Fibrin; Gelatin; Hemorrhage; Hemostatics; Humans; Polysaccharides; Surgical Mesh

Generation of a hemostatic clot requires thrombin-mediated conversion of fibrinogen to fibrin. Previous in vitro studies have demonstrated that the thrombin concentration present at the time of gelation profoundly influences fibrin clot structure. Clots formed in the presence of low thrombin concentrations are composed of thick fibrin fibers and are highly susceptible to fibrinolysis; while, clots formed in the presence of high thrombin concentrations are composed of thin fibers and are relatively resistant to fibrinolysis. While most studies of clot formation have been performed by adding a fixed amount of purified thrombin to fibrinogen, clot formation in vivo occurs in a context of continuous, dynamic changes in thrombin concentration. These changes depend on the local concentrations of pro- and anti-coagulants and cellular activities. Recent studies suggest that patterns of abnormal thrombin generation produce clots with altered fibrin structure and that these changes are associated with an increased risk of bleeding or thrombosis. Furthermore, it is likely that clot structure also contributes to cellular events during wound healing. These findings suggest that studies explicitly evaluating fibrin formation during in situ thrombin generation are warranted to explain and fully appreciate mechanisms of normal and abnormal fibrin clot formation in vivo.

Topics: Blood Coagulation; Fibrin; Hemorrhage; Humans; Macromolecular Substances; Protein Conformation; Thrombin; Thrombosis

Bleeding episodes in patients with hemophilia and inhibitors must be managed using agents that are hemostatically active in the absence of factor VIII or IX. Activated prothrombin complex concentrates have long been used in this context. However, the search for safer and more effective agents has led to the development of recombinant activated factor VII (rFVIIa; NovoSeven, Novo Nordisk, Bagsvaerd, Denmark). This paper presents an update on the mechanism of action of rFVIIa, and describes how pharmacologic doses of this agent enhance thrombin production and thus contribute to the development of a stable, lysis-resistant fibrin plug at the site of vessel damage. This mechanism explains the reported efficacy of rFVIIa in a range of clinical situations characterized by impaired thrombin generation.

Topics: Blood Coagulation; Dose-Response Relationship, Drug; Factor VII; Factor VIIa; Factor XI Deficiency; Fibrin; Hemophilia A; Hemorrhage; Humans; Recombinant Proteins; Thrombin

Topics: Animals; Factor XIa; Fibrin; Fibrinolytic Agents; Hemorrhage; Humans; Platelet Activation; Thrombosis

Alpha2-antiplasmin (alpha2AP) is the primary inhibitor of plasmin, a proteinase that digests fibrin, the main component of blood clots. Two forms of alpha2AP circulate in human plasma: a 464-residue protein with methionine as the amino-terminus (Met-alpha2AP) and an N-terminally-shortened 452-residue form with asparagine as the amino-terminus (Asn-alpha2AP). Human plasma alpha2AP concentration is 1 micro M and consists of approximately 30% Met-alpha2AP and approximately 70% Asn-alpha2AP. The major form (Asn-alpha2AP) is rapidly crosslinked to fibrin during blood clotting by activated coagulation factor XIII and as a consequence, fibrin becomes more resistant to fibrinolysis. It is apparent that alpha2AP is important in modulating the effectiveness and persistence of fibrin with respect to its susceptibility to digestion and removal by plasmin. Hence, the physiologic role of alpha2AP suggests that it may be a useful target for developing more effective treatment of thrombotic diseases. Research on alpha2AP appears to be moving in two main directions: (1) efforts to use variant forms of alpha2AP to reduce bleeding secondary to thrombolytic therapy while not slowing thrombolysis; and (2) efforts to use variant forms to diminish the activity of alpha2AP as a plasmin inhibitor so that fibrinolysis becomes enhanced. Methods to accomplish these two goals mostly involve manipulation of defined functional domains within the molecular structure of alpha2AP, or inhibition of a newly described novel plasma proteinase, termed antiplasmin-cleaving enzyme, that generates the more favorable form of alpha2AP, Asn-alpha2AP, for crosslinking to fibrin. The antiplasmin-cleaving enzyme has similarity in primary structure and catalytic properties to fibroblast activation protein/seprase. This review summarizes recent studies that may hold promise for modulating alpha2AP activity and its interactions with certain proteins as new therapeutic strategies for preventing and treating thrombotic disorders.

Topics: alpha-2-Antiplasmin; Fibrin; Hemorrhage; Humans; Thrombolytic Therapy; Treatment Outcome

Topics: Controlled Clinical Trials as Topic; Dose-Response Relationship, Drug; Fibrin; Fibrinolytic Agents; Hemorrhage; Humans; Metabolic Clearance Rate; Myocardial Infarction; Myocardial Reperfusion; Recombinant Proteins; Treatment Outcome

Current thrombolytic therapy fails to induce early, complete, and sustained reperfusion in +/-50% of the patients with ST-segment elevation acute coronary syndromes. There are two complementary approaches to improve thrombolytic therapy: the development of new fibrinolytics with enhanced fibrin specificity and/or reduced plasma clearance and the coadministration of new antithrombotic agents. The results obtained so far suggest that single-bolus fibrinolytic therapy is likely to replace the current infusions in the near future. This may result in a significantly earlier (prehospital) treatment of patients. The concomitant intravenous administration of a glycoprotein IIb/IIIa receptor antagonist (in combination with a reduced dose of a fibrinolytic) appears to be able to further enhance the efficacy for clot lysis without increasing the risk for bleeding complications.

Topics: Coronary Disease; Fibrin; Fibrinolytic Agents; Hemorrhage; Humans; Injections, Intravenous; Metabolic Clearance Rate; Myocardial Infarction; Myocardial Reperfusion; Platelet Glycoprotein GPIb-IX Complex; Platelet Glycoprotein GPIIb-IIIa Complex; Platelet Membrane Glycoproteins; Receptors, Antigen, B-Cell; Receptors, Cell Surface; Substrate Specificity; Thrombolytic Therapy; Time Factors; Tissue Plasminogen Activator

Pulmonary vascular inflammatory disorders may involve all components of the pulmonary vasculature, including capillaries. The principal histopathologic features of pulmonary capillaritis include capillary wall necrosis with infiltration by neutrophils, interstitial erythrocytes, and/or hemosiderin, and interalveolar septal capillary occlusion by fibrin thrombi. Immune complex deposition is variably present. Patients often present clinically with diffuse alveolar hemorrhage, which is characterized by dyspnea and hemoptysis; diffuse, bilateral, alveolar infiltrates on chest radiograph; and anemia. Pulmonary capillaritis has been reported with variable frequency and severity as a manifestation of Wegener's granulomatosis, microscopic polyarteritis, systemic lupus erythematosus, Goodpasture's syndrome, idiopathic pulmonary renal syndrome, Behçet's syndrome, Henoch-Schönlein purpura, IgA nephropathy, antiphospholipid syndrome, progressive systemic sclerosis, and diphenylhydantoin use. In addition to history, physical examination, and routine laboratory studies, certain ancillary laboratory tests, such as antineutrophil cytoplasmic antibodies, antinuclear antibodies, and antiglomerular basement membrane antibodies, may help diagnose an underlying disease. Diagnosis of pulmonary capillaritis can be made by fiberoptic bronchoscopy with transbronchial biopsy, but thoracoscopic biopsy is often employed. Since many disorders can result in pulmonary capillaritis with diffuse alveolar hemorrhage, it is crucial for clinicians and pathologists to work together when attempting to identify an underlying disease. Therapy depends on the disorder that gave rise to the pulmonary capillaritis and usually includes corticosteroids and cyclophosphamide or azathioprine. Since most diseases that result in pulmonary capillaritis are treated with immunosuppression, infection must be excluded aggressively.

Topics: Anemia; Bronchoscopy; Capillaries; Diagnosis, Differential; Dyspnea; Erythrocytes; Fibrin; Hemoptysis; Hemorrhage; Hemosiderin; Humans; Immunosuppressive Agents; Lung; Lung Diseases; Necrosis; Neutrophils; Pulmonary Alveoli; Pulmonary Embolism; Thoracoscopy; Vasculitis

Congenital factor XIII deficiency is a rare disease, but has provided valuable information on the physiological role of factor XIII and the benefit of factor XIII replacement therapy. It could be shown that not only homozygous patients but also heterozygotes are at risk for bleeding complications. Acquired factor XIII deficiency, however, is much more common, and preliminary studies suggest a lack of factor XIII to be an important feature of various diseases. In acute states and severe hemorrhages, replacement therapy with factor XIII concentrates is recommended. Recent progress in assay methods and future clinical studies should help to evaluate the therapeutic potential of factor XIII.

Topics: Autoantibodies; Autoimmune Diseases; Epitopes; Factor XIII; Factor XIII Deficiency; Female; Fibrin; Fracture Healing; Hemorrhage; Humans; Isoantibodies; Isoniazid; Male; Pregnancy; Pregnancy Complications, Hematologic; Wound Healing

Topics: Fibrin; Fibrinolysis; Fibrinolytic Agents; Hemorrhage; Humans; Isoantibodies; Plasma; Plasminogen Activators; Recurrence; Reference Standards; Streptokinase; Thrombelastography; Thromboembolism

Liver pathology is one of the main features of HELLP syndrome and develops on the basis of a generalised activation of intravascular coagulation. Fibrin deposits and haemorrhagic necrosis predominantly develop in the periportal areas and may eventually lead to subcapsular haematomas or even rupture of the liver. While the compensated form of activation of intravascular coagulation, which is diagnosed by a decrease in antithrombin III and an increase in thrombin-antithrombin III complex (TAT) and the appearance of fibrin, monomers and D-dimers, is found in almost all cases of HELLP syndrome, the decompensated form of intravascular coagulation with prolonged bleeding time (PT, PTT) and drop in fibrinogen is found only in the most severe forms. The development of a decompensation of coagulation correlates with the appearance of severe complications such as liver haematoma, abruptio placentae, renal failure and pulmonary oedema. The best prophylaxis against the development of life-threatening complications is early diagnosis and termination of pregnancy after stabilisation of the maternal condition, consisting of magnesium sulphate infusion, antihypertensive treatment with dihydralazine or calcium antagonists, steroids etc. Severe complications of HELLP syndrome have occasionally been observed in the postpartum period. As prophylaxis against postpartal worsening of HELLP syndrome, curettage of the uterus and continuation of the treatment with calcium antagonists and dexamethasone have been recommended.

Topics: Biopsy; Blood Coagulation Tests; Disseminated Intravascular Coagulation; Female; Fibrin; HELLP Syndrome; Hemorrhage; Humans; Infant, Newborn; Liver; Necrosis; Pregnancy; Rupture, Spontaneous

We reviewed the histopathologic characteristics of DIC in autopsy cases. Typical hyaline microthrombi preferentially occurred in renal glomeruli, pulmonary microvasculature, splenic sinuses, adrenocortical capillaries and others, occasionally associated with degenerative or necrotic changes of parenchymal cells of respective organs partly due to ischemic effects of microthrombi and thromboemboli. Investigating the pathogenesis of microthrombi in hepatic sinusoids of rats intravenously injected with LPS (5 mg/kg B.W.) using double immunohistochemical reactions for LPS and fibrinogen, and electron microscopic observations, fibrin thrombi were largely formed around small necrotic foci of hepatocytes 1 hr after injection, which occurred in the very close vicinity to Kupffer cells phagocytizing LPS, and on the cytoplasmic surface of swollen Kupffer cells lading LPS 3 hr after injection. Neutrophils always aggregated in the necrotic foci. Thus, activated Kupffer cells by LPS seemed to play a central role in the development of fibrin thrombi in hepatic sinusoids of endotoxemic rats, through the activation of coagulation system probably via the expression of tissue factor by activated Kupffer cells.

Topics: Animals; Disseminated Intravascular Coagulation; Fibrin; Hemorrhage; Humans; Ischemia; Kidney Glomerulus; Lipopolysaccharides; Macrophages; Microcirculation; Thrombosis

Activation and inhibition of the haemostatic system was reviewed including the interaction between the four biological systems involved in haemostasis: the vessel wall, the platelets, the coagulation system and the fibrinolytic system. The haemostatic mechanism is initiated at the site of injury through local activation of surfaces and release of tissue thromboplastin, resulting in formation and deposition of fibrin. The coagulation process is regulated by physiological anticoagulants. Activation of fibrinolysis is triggered by the presence of fibrin, and the role of tissue-type plasminogen activators (t-PA) at the site of fibrin formation in particular is emphasized. The process is regulated by physiological inhibitors, of which alpha 2-antiplasmin, histidine-rich glycoprotein and plasminogen activator inhibitor are reported to be of major physiological significance. The role of fibrinolysis in the regulation of the dynamic haemostatic balance is discussed, elucidated through examples of congenital deficiencies of the coagulation and the fibrinoytic system. Pharmacological inhibitors of fibrinolysis (i.e. epsilon-aminocaproic acid and tranexamic acid) and their possible effect on the haemostatic system are described. The systemic effects on the fibrinolytic system of surgery and oral surgery is reviewed, and it is concluded, that oral surgery has insignificant effects on blood fibrinolysis. In contrast, oral surgery induces changes of fibrinolysis in the oral environment; initially the fibrinolytic activity of saliva is reduced, due to the presence of inhibitors of fibrinolysis originating from the blood and the wound exudate. When bleeding and exudation cease, the fibrinolytic activity of the saliva will increase. Plasminogen and plasminogen activator, identified as t-PA are present in the oral environment under physiological conditions. Plasminogen is secreted in the saliva and the sources of t-PA include oral epithelial cells and gingival crevicular fluid. The presence of plasminogen and t-PA in the oral environment implies that when fibrin is present (i.e. after surgery), fibrinolysis is triggered. Haemorrhagic complications to oral surgery in patients without known defects of the coagulation system is reviewed. It is concluded that the investigations conducted to the present day do not permit final conclusions with respect to the pathophysiological role of defects in the coagulation and the fibrinolytic systems for the development of bleeding after

Topics: Anticoagulants; Blood Coagulation; Blood Platelets; Deamino Arginine Vasopressin; Fibrin; Fibrinolysis; Gingiva; Hemophilia A; Hemorrhage; Hemostasis; Hemostasis, Surgical; Humans; Mouth Mucosa; Saliva; Surgery, Oral; Tissue Plasminogen Activator; von Willebrand Diseases

Topics: Animals; Disease Models, Animal; Fibrin; Glomerulonephritis; Hemorrhage; Humans; Kidney Glomerulus; Tissue Plasminogen Activator

The use of clotting substances from blood for hemostasis dates back to 1909. In 1972, modern fibrin sealing (FS) was developed in Vienna. For application, the two components, i.e., a sealer protein solution (mainly fibrinogen) and a thrombin solution, are mixed to produce the fibrin clot. The sealant may be applied with a needle, as a spray, or by premixing (e.g., with antibiotics, bone chips) for subsequent sealant application in cavities. While the positive effect of FS in normal wound healing has been conclusively demonstrated, its influence on bone healing remains controversial. The positive experimental results mostly refer to the early phase of bone healing in rabbits (cortical drill hole, autologous and heterologous (Kiel) cancellous transplants, osteotomies, osteochondral fractures) and dogs (cortical bone and spongiosa defects). Some authors observed no effects (in dogs, osteotomy) or delayed healing in artificial bone growth chambers with the use of heterologous sealant. FS was also applied in combination with implantation material (tricalcium phosphate and bone gelatin) to facilitate application. Clinical results are especially convincing as to osteochondral fractures, repair of the Achilles tendon, and in hemophiliacs. Fibrin sealant facilitates hemostasis, permits tissue fixation, enhances plasticity of granular implant material, and stimulates fibroblast growth. Although its direct osteogenic effect remains questionable, fibrin sealant is known to be an excellent tool in orthopedic and trauma surgery.

Topics: Animals; Aprotinin; Bone and Bones; Cartilage; Dogs; Drug Combinations; Factor XIII; Fibrin; Fibrin Tissue Adhesive; Fibrinogen; Fractures, Bone; Hemophilia A; Hemorrhage; Hemostasis; Humans; Rabbits; Tendon Injuries; Thrombin; Tissue Adhesives; Wound Healing

Topics: Animals; Blood Coagulation Factors; Blood Coagulation Tests; Blood Platelets; Drug Evaluation; Fibrin; Fibrin Fibrinogen Degradation Products; Fibrinogen; Fibrinolysin; Fibrinolytic Agents; Hemorrhage; Humans; Myocardial Infarction; Plasminogen Activators; Streptokinase; Thrombin; Thromboembolism

Physiologic thrombolysis is efficient, while pathologic aberrations in the fibrinolytic system may result in either thrombotic or hemorrhagic disease. This review considers the molecular interactions involved in fibrinolysis, discusses the normal control mechanisms that provide for localized activation without systemic effects, and describes the molecular mechanism of plasmic degradation of fibrinogen and of cross-linked fibrin. The consequences of excessive or deficient fibrinolysis are discussed and specific examples cited of pathologic hemostasis directly related to abnormalities in the fibrinolytic system.

Topics: alpha-2-Antiplasmin; Animals; Blood Coagulation; Blood Coagulation Disorders; Disseminated Intravascular Coagulation; Dogs; Fibrin; Fibrin Fibrinogen Degradation Products; Fibrinogen; Fibrinolysin; Fibrinolysis; Fibrinolytic Agents; Hemorrhage; Homeostasis; Humans; Iatrogenic Disease; Plasminogen; Plasminogen Activators; Rabbits; Streptokinase; Thrombosis; Urokinase-Type Plasminogen Activator

Topics: Actins; Adenosine Triphosphate; Blood Platelets; Blood Proteins; Clot Retraction; Disseminated Intravascular Coagulation; Energy Metabolism; Fibrin; Fibrinolysis; Hemorrhage; Hemostasis; Humans; Kinetics; Myosins; Regeneration; Thrombelastography

Disturbances of the hemostatic system which may be caused by chemicals include hemorrhagic diathesis, caused by inhibition of blood clotting, impairment of platelet function, and hyperactivity of fibrinolysis. Activation of the plasmatic clotting system, platelet aggregation, and inhibition of fibrinolysis may lead to thromboembolic complications. Although much is known about the functions of the hemostatic system a rational and cost-effective approach for its assessment in industrial toxicology is lacking. In this review the physiology of hemostasis and the available laboratory tests are discussed, current regulatory requirements are described, and industry practice is analyzed based on experience accumulated over the last 23 years. Proposals for a more flexible and scientific approach to testing of hemostatic mechanisms in toxicology are made.

Topics: Animals; Blood Coagulation; Blood Coagulation Tests; Drug Industry; Fibrin; Government Agencies; Hemorrhage; Hemostasis; Humans; Platelet Function Tests; Toxicology; United States

Topics: Aminocaproic Acid; Antifibrinolytic Agents; Aprotinin; Caseins; Fibrin; Fibrinolysin; Fibrinolysis; Hemorrhage; Humans; Tranexamic Acid

Topics: Blood Coagulation; Fibrin; Fibrinogen; Fibrinolysis; Hemorrhage; Heparin; Humans; Neoplasm Metastasis; Neoplasms; Thromboplastin; Thrombosis

Topics: Animals; Blood Coagulation; Blood Protein Electrophoresis; Calcium; Enzyme Activation; Factor XII; Factor XIII; Factor XIII Deficiency; Fibrin; Fibrinogen; Fibrinolysin; Half-Life; Hemorrhage; Hemorrhagic Disorders; Hemostasis; Heparin; Humans; Molecular Weight; Rats; Sulfhydryl Compounds; Thrombin

Topics: Abortion, Spontaneous; Blood; Blood Coagulation Tests; Blood Platelets; Cerebral Hemorrhage; Ecchymosis; Factor XIII; Factor XIII Deficiency; Female; Fetal Death; Fibrin; Hematoma; Hemorrhage; Hemorrhagic Disorders; Humans; Infant, Newborn; Placenta; Pregnancy; Pregnancy Complications, Hematologic; Umbilical Cord

Topics: Anemia, Hemolytic; Animals; Blood Coagulation; Blood Coagulation Factors; Blood Platelets; Blood Viscosity; Drug Resistance; Female; Fibrin; Fibrinogen; Fibrinolysis; Fibrinolytic Agents; Hemorrhage; Heparin; Humans; Hydrolysis; Iodine Radioisotopes; Peptide Hydrolases; Plasminogen; Pregnancy; Snake Venoms; Thrombin; Thromboembolism; Urokinase-Type Plasminogen Activator; Wound Healing

Topics: Adult; Afibrinogenemia; Blood Coagulation; Blood Protein Disorders; Blood Transfusion; Child; Child, Preschool; Factor XIII; Female; Fibrin; Fibrinogen; Glutaminase; Hemorrhage; Humans; Infant, Newborn; Male; Prothrombin Time

Topics: Animals; Aorta; Arteriosclerosis; Blood Platelets; Calcinosis; Child; Cholesterol; Collateral Circulation; Coronary Disease; Coronary Vessels; Erythrocytes; Female; Fibrin; Fibroblasts; Glycosaminoglycans; Hemorrhage; Histocytochemistry; Humans; Lipids; Macrophages; Male; Middle Aged; Muscle, Smooth; Necrosis; Rabbits; Rupture; Thrombosis

Topics: Animals; Antibodies; Arteries; Blood Platelets; Capillaries; Coronary Disease; Coronary Vessels; Cortisone; Dogs; Endocarditis; Fibrin; Graft Rejection; Heart Failure; Heart Transplantation; Hemorrhage; Humans; Immunosuppression Therapy; Immunosuppressive Agents; Infections; Kidney Transplantation; Male; Microscopy, Electron; Middle Aged; Myocarditis; Myocardium; Necrosis; Rabbits; Shwartzman Phenomenon; Time Factors; Transplantation Immunology; Transplantation, Homologous

Topics: Adult; Aged; Autopsy; Brain; Central Venous Pressure; Colitis; Colon; Enteritis; Female; Fibrin; Heart Ventricles; Hemorrhage; Humans; Kidney; Kidney Glomerulus; Kidney Tubules; Liver; Lung; Male; Middle Aged; Myocardium; Necrosis; Pancreas; Shock; Thrombosis

Topics: Acetylcholine; Antimetabolites; Aspirin; Autonomic Nervous System; Blood Circulation; Blood Coagulation Disorders; Blood Coagulation Factors; Blood Platelets; Calcium; Cell Aggregation; Clot Retraction; Dicumarol; Epinephrine; Factor IX; Factor V; Factor VII; Factor VIII; Factor X; Fibrin; Fibrinogen; Hemorrhage; Hemostasis; Humans; Prothrombin; Prothrombin Time; Surgical Procedures, Operative; Thrombin; Vasoconstrictor Agents; Vasodilator Agents; Vitamin K

Topics: Abruptio Placentae; Adrenal Glands; Aminocaproates; Animals; Basement Membrane; Biopsy; Blood Coagulation Disorders; Blood Coagulation Factors; Blood Platelets; Brain; Female; Fibrin; Fibrinogen; Fibrinolysis; Fluorescent Antibody Technique; Hemorrhage; Hemorrhagic Disorders; Heparin; Humans; Hypertension, Malignant; Kidney Cortex Necrosis; Kidney Failure, Chronic; Kidney Glomerulus; Liver; Maternal Mortality; Microscopy, Electron; Myocardium; Placental Extracts; Pre-Eclampsia; Pregnancy; Rabbits; Shwartzman Phenomenon; Thromboplastin; Thrombosis

Topics: Anticoagulants; Blood Cell Count; Blood Coagulation Tests; Blood Platelets; Diagnosis, Differential; Fibrin; Fibrinogen; Hemorrhage; Hemorrhagic Disorders; Humans; Prothrombin; Prothrombin Time; Thromboplastin; Vascular Resistance

Topics: Blood Coagulation; Blood Coagulation Disorders; Blood Coagulation Factors; Blood Platelets; Blood Vessels; Capillary Permeability; Fibrin; Fibrinogen; Hemorrhage; Hemostasis; Humans

Topics: Animals; Aorta; Arteriosclerosis; Blood Coagulation; Blood Coagulation Disorders; Blood Vessels; Endocrine Glands; Fibrin; Fibrinogen; Fibrinolysis; Hemorrhage; Heparin; Heparin Antagonists; Hepatitis; Humans; Lipid Metabolism; Lipoprotein Lipase; Liver; Liver Cirrhosis; Stress, Physiological; Thrombin; Thrombosis; Triglycerides

Topics: Blood Coagulation Factors; Blood Platelets; Diagnosis, Differential; Factor VII Deficiency; Fibrin; Fibrinolysis; Hemophilia A; Hemophilia B; Hemorrhage; Humans; Hypoprothrombinemias; Prothrombin Time; Thrombin; Vitamin K Deficiency

Compare the effect of apixaban and warfarin on coagulation and primary haemostasis biomarkers in atrial fibrillation (AF).. The biomarker substudy from the Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation trial included 4850 patients with AF randomised to treatment with apixaban or warfarin. Sixty per cent of patients used vitamin K antagonist (VKA) within 7 days before randomisation. Prothrombin fragment 1+2 (F1+2), D-dimer, soluble CD40 ligand (sCD40L) and von Willebrand factor (vWF) antigen were analysed at randomisation and after 2 months of study treatment.. In patients not on VKA treatment at randomisation, F1+2 and D-dimer levels were decreased by 25% and 23%, respectively, with apixaban, and by 59% and 38%, respectively, with warfarin (p<0.0001 for treatment differences for both). In patients on VKA at randomisation, F1+2 and D-dimer levels increased by 41% and 10%, respectively, with apixaban and decreased by 37% and 11%, respectively, with warfarin (p<0.0001 for treatment differences for both). sCD40L levels were slightly increased at 2 months, regardless of VKA or randomised treatment. Apixaban and warfarin also both reduced vWF antigen regardless of VKA treatment. The efficacy (stroke) and safety (bleeding) of apixaban compared with warfarin was similar irrespectively of biomarker levels at 2 months.. Treatment with apixaban compared with warfarin for stroke prevention in patients with AF was associated with less reduction in thrombin generation and fibrin turnover. This effect of apixaban could contribute to the clinical results where apixaban was superior to warfarin both in stroke prevention and in reducing bleeding risk.. NCT00412984.

Topics: Aged; Anticoagulants; Atrial Fibrillation; Biomarkers; Blood Coagulation; Female; Fibrin; Fibrin Fibrinogen Degradation Products; Hemorrhage; Humans; Male; Middle Aged; Pyrazoles; Pyridones; Risk Assessment; Stroke; Thrombin; Treatment Outcome; Warfarin

To determine whether fibrin clot properties are associated with clinical outcomes following acute coronary syndrome (ACS).. Plasma samples were collected at hospital discharge from 4354 ACS patients randomized to clopidogrel or ticagrelor in the PLATelet inhibition and patient Outcomes (PLATO) trial. A validated turbidimetric assay was employed to study plasma clot lysis time and maximum turbidity (a measure of clot density). One-year rates of cardiovascular (CV) death, spontaneous myocardial infarction (MI) and PLATO-defined major bleeding events were assessed after sample collection. Hazard ratios (HRs) were estimated using Cox proportional hazards models. After adjusting for CV risk factors, each 50% increase in lysis time was associated with CV death/spontaneous MI [HR 1.17, 95% confidence interval (CI) 1.05-1.31; P < 0.01] and CV death alone (HR 1.36, 95% CI 1.17-1.59; P < 0.001). Similarly, each 50% increase in maximum turbidity was associated with increased risk of CV death (HR 1.24, 95% CI 1.03-1.50; P = 0.024). After adjustment for other prognostic biomarkers (leukocyte count, high-sensitivity C-reactive protein, high-sensitivity troponin T, cystatin C, N-terminal pro B-type natriuretic peptide, and growth differentiation factor-15), the association with CV death remained significant for lysis time (HR 1.2, 95% CI 1.01-1.42; P = 0.042) but not for maximum turbidity. These associations were consistent regardless of randomized antiplatelet treatment (all interaction P > 0.05). Neither lysis time nor maximum turbidity was associated with major bleeding events.. Fibrin clots that are resistant to lysis independently predict adverse outcome in ACS patients. Novel therapies targeting fibrin clot properties might be a new avenue for improving prognosis in patients with ACS.

Topics: Acute Coronary Syndrome; Aged; Blood Coagulation; Clopidogrel; Double-Blind Method; Female; Fibrin; Fibrin Clot Lysis Time; Hemorrhage; Humans; Male; Middle Aged; Myocardial Infarction; Platelet Aggregation Inhibitors; Ticagrelor; Treatment Outcome

We evaluated hemostatic markers in patients who underwent major orthopedic surgery, including total hip and total knee arthroplasty, and were treated for the prophylaxis of deep vein thrombosis (DVT) with or without fondaparinux (anti-Xa group, n = 98 and without anti-Xa group, n = 20). The frequency of DVT was significantly higher in the without anti-Xa group than in the anti-Xa group, but the reduction of hemoglobin and fibrinolytic marker levels was significantly lower in the without anti-Xa group than in the anti-Xa group. Eighteen patients in the anti-Xa group showed a reduction in hemoglobin of more than 2 g/dl, and those individuals were considered to be the increased bleeding (IB) group. The concentration of fibrinolytic markers in the anti-Xa group was significantly higher in the IB group than in the non-IB group. There were also no significant differences in the levels of anti-Xa activity, plasminogen activator inhibitor-I, soluble fibrin and antithrombin between the IB and non-IB groups. In conclusion, elevated fibrinolysis induced by increased bleeding may lead to further increases in bleeding in patients receiving thromboprophylaxis with fondaparinux following major orthopedic surgery.

Topics: Aged; Anticoagulants; Arthroplasty, Replacement, Hip; Arthroplasty, Replacement, Knee; Biomarkers; Factor Xa Inhibitors; Female; Fibrin; Fibrin Fibrinogen Degradation Products; Fibrinogen; Fibrinolysis; Fondaparinux; Hemorrhage; Humans; Male; Middle Aged; Polysaccharides; Postoperative Complications; Venous Thrombosis

Enoxaparin was superior to unfractionated heparin (UFH), regardless of fibrinolytic agent in ST-elevation myocardial infarction (STEMI) patients receiving fibrinolytic therapy in ExTRACT-TIMI 25 (Enoxaparin and Thrombolysis Reperfusion for Acute Myocardial Infarction Treatment - Thrombolysis in Myocardial Infarction 25) trial.. This post hoc analysis compared outcomes with streptokinase plus enoxaparin to the standard regimen of fibrin-specific lytic (FSL) plus UFH and to the newer combination of FSL plus enoxaparin.. In ExTRACT-TIMI 25, STEMI patients received either streptokinase or a FSL (alteplase, reteplase or tenecteplase) at the physician's discretion and were randomized to enoxaparin or UFH, stratified by fibrinolytic type. Thirty-day outcomes were adjusted for baseline characteristics, region, in-hospital percutaneous coronary intervention (PCI) and a propensity score for the choice of lytic.. The primary trial endpoint of 30-day death/myocardial infarction (MI) occurred in fewer patients in the streptokinase-enoxaparin cohort (n = 2083) compared with FSL-UFH (n = 8141) [10.2% vs 12.0%, adjusted odds ratio [OR(adj)] 0.76; 95% CI 0.62, 0.93; p = 0.008]. Major bleeding was significantly increased with streptokinase-enoxaparin compared with FSL-UFH (OR(adj) 2.74; 95% CI 1.81; 4.14; p < 0.001) but intracranial haemorrhage (ICH) was similar (OR(adj) 0.90; 95% CI 0.40, 2.01; p = 0.79). Net clinical outcomes, defined as either death/MI/major bleeding or as death/MI/ICH tended to favour streptokinase-enoxaparin compared with FSL-UFH (OR(adj) 0.88; 95% CI 0.73, 1.06; p = 0.17; and OR(adj) 0.77; 95% CI 0.63, 0.93; p = 0.008, respectively). Patients receiving FSL-enoxaparin (n = 8142) and streptokinase-enoxaparin therapies experienced similar adjusted rates of the primary endpoint (OR(adj) 1.08; 95% CI 0.87, 1.32; p = 0.49) and net clinical outcomes.. Our results suggest that fibrinolytic therapy with the combination of streptokinase and the potent anticoagulant agent enoxaparin resulted in similar adjusted outcomes compared with more costly regimens utilizing a FSL.

Topics: Adult; Aged; Angioplasty, Balloon, Coronary; Cohort Studies; Drug Therapy, Combination; Endpoint Determination; Enoxaparin; Female; Fibrin; Fibrinolytic Agents; Hemorrhage; Humans; Male; Middle Aged; Myocardial Infarction; Plasminogen Activators; Recombinant Proteins; Streptokinase; Tenecteplase; Thrombolytic Therapy; Time Factors; Tissue Plasminogen Activator; Treatment Outcome; Young Adult

In trauma patients, resuscitation to endpoints below normal blood pressure (BP) levels may reduce further blood loss due to the rebleeding often caused by more aggressive resuscitation. However, patients whose BP is maintained at lower levels for extended periods are at increased risk for organ failure. The purpose of this study was to determine whether recombinant activated factor VII (rFVIIa) raises the BP level at which rebleeding occurs in a prospective, randomized, blinded study using a porcine model of uncontrolled hemorrhage and resuscitation. Thirty anesthetized 40-kg pigs were assigned to three groups (n = 10/group): control, low-dose rFVIIa (180 microg/kg), or high-dose (720 microg/kg). Vehicle or drug was infused 5 min before creating a 2.0-mm infrarenal aortotomy. Ten minutes later, resuscitation with lactated Ringer's (LR) solution at 100 mL/min was begun. Hemorrhage and LR volumes and BP were recorded continuously. We found that pretreatment with rFVIIa increased the mean arterial pressure at which rebleeding occurred during resuscitation (45 +/- 3, 69 +/- 5, and 66 +/- 6 mmHg in the control, low-dose, and high-dose groups, respectively, P = 0.003). Rebleed hemorrhage volume was reduced with rFVIIa (39 +/- 9, 22 +/- 7, and 26 +/- 5 mL/kg for control, and low and high dose, respectively; P = 0.055). This is the first study to show that rFVIIa increases the BP at which rebleeding occurs during resuscitation in an injury to a major artery, suggesting the formation of a tight, stronger fibrin plug in the presence of high concentrations of rFVIIa.

Topics: Animals; Antithrombins; Aorta; Aortic Diseases; Blood Pressure; Body Weight; Disease Models, Animal; Factor VII; Factor VIIa; Female; Fibrin; Hemorrhage; Pressure; Prospective Studies; Recombinant Proteins; Resuscitation; Secondary Prevention; Swine; Thrombin; Time Factors; Treatment Outcome

Despite the efficacy of antifibrinolytic drugs in reducing bleeding after cardiac surgery, concerns remain regarding their potential to promote thrombosis. We examined the effect of the antifibrinolytic drug, epsilon-aminocaproic acid (EACA) on fibrinolysis and thrombin generation during cardiac surgery. Forty-one adults undergoing primary coronary artery bypass graft surgery requiring cardiopulmonary bypass (CPB) were prospectively randomized in a double-blind trial to receive either saline or EACA. A loading dose of 150 mg/kg EACA was given before anesthetic induction, followed by a 15 mg x kg(-1) x h(-1) infusion, which continued until 3 h after CPB. Plasma samples for the measurement of D-dimer, thrombin-antithrombin III, and soluble fibrin were obtained before surgery, 1 h on CPB, and 3 and 20 h after CPB. In the EACA group, fibrinolytic activity, as measured by D-dimer, was significantly decreased 3 h after CPB, (0.51 +/- 0.15 mg/L vs 1.13 +/- 0.14 mg/L, P < 0.005). Decreased fibrinolytic activity was accompanied by decreased bleeding in the EACA group (660 +/- 127 mL vs 931 +/- 113 mL, P < 0.05). No differences in the generation of thrombin or soluble fibrin were apparent between the two groups. Suppression of fibrinolytic activity in the absence of concomitant reductions in thrombin generation suggests that EACA could potentiate a hypercoagulable prethrombotic state in the perioperative setting.. In a randomized, prospective trial of primary cardiac surgery, we demonstrated that the synthetic antifibrinolytic drug epsilon-aminocaproic acid suppresses fibrinolysis with no effects on thrombin generation. These results suggest the potential for synthetic antifibrinolytic drugs to induce a hypercoagulable prethrombotic state in the perioperative setting.

Topics: Aminocaproic Acid; Antifibrinolytic Agents; Antithrombin III; Cardiopulmonary Bypass; Coronary Artery Bypass; Double-Blind Method; Female; Fibrin; Fibrinolysis; Hemorrhage; Humans; Male; Middle Aged; Peptide Hydrolases; Postoperative Complications; Prospective Studies; Thrombin

The aim of this study was to assess the hemorrhagic risk associated with fibrin-specific thrombolytic therapy and invasive procedures with acute myocardial infarction.. Successful coronary artery reperfusion has important prognostic implications. Because immediate coronary angiography is the only method proved to differentiate early fibrinolytic success from failure, its use may be important for selected patients.. Five hundred seventy-five patients were evaluated with six combined thrombolytic and catheterization strategies. Patients were randomized to intravenous urokinase alone, recombinant tissue-type plasminogen activator (rt-PA) alone, or both; simultaneously they were randomized to an immediate versus a deferred catheterization strategy. Hemorrhagic events were assessed. The correlation of hemorrhage with clinical and hemostatic variables was evaluated. Prespecified transfusion criteria were employed.. No difference in baseline characteristics or in hemorrhagic complications was noted among the three thrombolytic regimens. Although mild (< 250 ml) bleeding was more common in the group with immediate catheterization, no clinically significant difference among catheterization groups was seen in moderate to life-threatening hemorrhagic events. Most bleeding occurred at vascular access sites, yet severe and life-threatening hemorrhage occurred in < 1% of patients. Baseline and nadir fibrinogen levels, change in baseline fibrinogen levels and peak fibrin and fibrinogen degradation products did not correlate with bleeding risk. A clinical predisposition for bleeding was observed in women as well as older (> or = 65 years) and lighter (< or = 70 kg) patients. With prespecified transfusion criteria, only a minimal increase in blood product usage was noted with immediate catheterization.. Immediate cardiac catheterization can be accomplished without a clinically significant difference in bleeding risk. Fibrin specificity offers no clear advantage in reducing hemorrhagic risk. Bleeding risk correlates best with baseline patient characteristics. Finally, the amount of blood transfused can be reduced with lower transfusion criteria.

Topics: Cardiac Catheterization; Female; Fibrin; Hemorrhage; Humans; Male; Middle Aged; Myocardial Infarction; Risk Factors; Thrombolytic Therapy; Time Factors; Tissue Plasminogen Activator; Urokinase-Type Plasminogen Activator

A method for instilling a two-component fibrin adhesive into the prostatic cavity after transurethral resection of the prostate is described. In a prospective, controlled study, 30 consecutive patients undergoing transurethral prostatectomy (TURP) were randomised either to receive treatment with the local instillation of fibrin adhesive into the prostatic cavity or to a control group that received no special treatment post-operatively. There were no complications either during application of the fibrin adhesive or in the follow-up period. Post-operative blood loss was significantly reduced in the fibrin group (P less than 0.01).

Topics: Fibrin; Hemorrhage; Hemostasis, Surgical; Humans; Male; Postoperative Complications; Prostatectomy; Time Factors; Tissue Adhesives

Bleeding is a serious complication of cardiopulmonary bypass (CPB) in neonates. Blood product transfusions are often needed to adequately restore hemostasis, but are associated with significant risks. Thus, neonates would benefit from other effective, and safe, hemostatic therapies. The use of fibrinogen concentrate (FC; RiaSTAP, CSL Behring, Marburg, Germany) is growing in popularity, but has not been adequately studied in neonates. Here, we characterize structural and degradation effects on the neonatal fibrin network when FC is added ex vivo to plasma obtained after CPB.. After approval by the institutional review board and parental consent, blood samples were collected from neonates undergoing cardiac surgery and centrifuged to yield platelet poor plasma. Clots were formed ex vivo from plasma obtained at several time points: (1) baseline, (2) immediately post-CPB, and (3) post-transfusion of cryoprecipitate. In addition, we utilized post-CPB plasma to construct the following conditions: (4) post-CPB +0.5 mg/mL FC, and (5) post-CPB +0.9 mg/mL FC. The resultant fibrin networks were imaged using confocal microscopy to analyze overall structure, fiber density, and alignment. Clots were also analyzed using a microfluidic degradation assay. Fibrinogen content was quantified for all plasma samples.. The addition of 0.5 or 0.9 mg/mL FC to post-CPB samples significantly enhanced the median fiber density when compared to untreated post-CPB samples (post-CPB = 0.44 [interquartile range {IQR}: 0.36-0.52], post-CPB +0.5 mg/mL FC = 0.69 [0.56-0.77], post-CPB +0.9 mg/mL FC = 0.87 [0.59-0.96]; P = .01 and P = .006, respectively). The addition of 0.9 mg/mL FC to post-CPB samples resulted in a greater fiber density than that observed after the in vivo transfusion of cryoprecipitate (post-transfusion = 0.54 [0.45-0.77], post-CPB +0.9 mg/mL FC = 0.87 [0.59-0.96]; P = .002). Median fiber alignment did not differ significantly between post-CPB samples and samples treated with FC. Degradation rates were not statistically significant from baseline values with either 0.5 or 0.9 mg/mL FC. In addition, we found a significant correlation between the difference in the baseline and post-CPB fibrinogen concentration with patient age ( P = .033) after controlling for weight.. Our results show that clots formed ex vivo with clinically relevant doses of FC (0.9 mg/mL) display similar structural and degradation characteristics compared to the in vivo transfusion of cryoprecipitate. These findings suggest that FC is effective in restoring structural fibrin clot properties after CPB. Future studies after the administration of FC in vivo are needed to validate this hypothesis.

Topics: Cardiopulmonary Bypass; Fibrin; Fibrinogen; Hemorrhage; Hemostatics; Humans; Infant, Newborn; Thrombosis

 Catheter-directed thrombolysis (CDT) is an effective therapy for acute deep vein thrombosis (DVT). However, predicting the CDT outcomes remains elusive. We hypothesized that the thrombus signal on T1-weighted black-blood magnetic resonance (MR) can provide insight into CDT outcomes in acute DVT patients..  A total of 117 patients with acute iliofemoral DVT were enrolled for T1-weighted black-blood MR before CDT in this prospective study. Based on the signal contrast between thrombus and adjacent muscle, patients were categorized into the iso-intense thrombus (Iso-IT), hyper-intense thrombus (Hyper-IT), and mixed iso-/hyper-intense thrombi (Mixed-IT) groups. Immediate treatment outcome (i.e., vein patency) and long-term treatment outcome (i.e., the incidence rate of postthrombotic syndrome) were accessed by the same expert. Histological analysis and iron quantification were performed on thrombus samples to characterize the content of fibrin, collagen, and the ratio of Fe.  Compared to Mixed-IT and Hyper-IT groups, the Iso-IT group had the best lytic effect (90.5 ± 1.6% vs. 78.4 ± 2.6% vs. 46.5 ± 3.3%,.  Thrombus signal characteristics on T1-weighted black-blood MR is associated with CDT outcomes and possesses potential to serve as a noninvasive approach to guide treatment decision making in acute DVT patients.. · Thrombus signal on T1-weighted black-blood MR is associated with lytic therapeutic outcome in acute DVT patients.. · Presence of iso-intense thrombus revealed by T1-weighted black-blood MRI is associated with successful thrombolysis, low bleeding ratio, and low incidence of the postthrombotic syndrome.. · T1-weighted thrombus signal characteristics may serve as a noninvasive imaging marker to predict CDT treatment outcomes and therefore guide treatment decision making in acute DVT patients..

Topics: Catheters; Femoral Vein; Fibrin; Hemorrhage; Humans; Iliac Vein; Magnetic Resonance Imaging; Magnetic Resonance Spectroscopy; Postphlebitic Syndrome; Postthrombotic Syndrome; Prospective Studies; Retrospective Studies; Thrombolytic Therapy; Treatment Outcome; Venous Thrombosis

Primary hemostasis (platelet plug formation) and secondary hemostasis (fibrin clot formation) are intertwined processes that occur upon vascular injury. Researchers have sought to target wounds by leveraging cues specific to these processes, such as using peptides that bind activated platelets or fibrin. While these materials have shown success in various injury models, they are commonly designed for the purpose of treating solely primary or secondary hemostasis. In this work, a two-component system consisting of a targeting component (azide/GRGDS PEG-PLGA nanoparticles) and a crosslinking component (multifunctional DBCO) is developed to treat internal bleeding. The system leverages increased injury accumulation to achieve crosslinking above a critical concentration, addressing both primary and secondary hemostasis by amplifying platelet recruitment and mitigating plasminolysis for greater clot stability. Nanoparticle aggregation is measured to validate concentration-dependent crosslinking, while a 1:3 azide/GRGDS ratio is found to increase platelet recruitment, decrease clot degradation in hemodiluted environments, and decrease complement activation. Finally, this approach significantly increases survival relative to the particle-only control in a liver resection model. In light of prior successes with the particle-only system, these results emphasize the potential of this technology in aiding hemostasis and the importance of a holistic approach in engineering new treatments for hemorrhage.

Topics: Azides; Blood Platelets; Fibrin; Hemorrhage; Hemostasis; Humans; Thrombosis; Vascular Diseases

Several studies have demonstrated the clinical utility of tranexamic acid (TXA) for use in trauma patients presenting with significant hemorrhage. Tranexamic acid is an antifibrinolytic that inhibits plasminogen activation, and plasmin activity has been shown to mitigate blood loss and reduce all-cause mortality in the absence of adverse vascular occlusive events. Recent clinical developments indicate TXA is safe to use in patients with concomitant traumatic brain injury (TBI); however, the prehospital effects are not well understood. Importantly, TXA has been associated with seizure activity. Therefore, this study sought to evaluate the effects of early administration of TXA on neurological recovery and electroencephalogram (EEG) abnormalities following penetrating TBI with concomitant hypoxemia and hemorrhagic shock. We hypothesized that early administration of TXA will provide hemodynamic stabilization and reduce intracerebral hemorrhage, which will result in improved neurological function. To test this hypothesis, Sprague-Dawley rats received a unilateral, frontal penetrating ballistic-like brain injury by inserting a probe into the frontal cortex of the anesthetized rat. Five minutes following brain injury, animals underwent 30 min of respiratory distress and 30 min of hemorrhage. Upon completion of the hemorrhage phase, animals received the initial dose of drug intravenously over 10 min after which the prehospital phase was initiated. During the prehospital phase, animals received autologous shed whole blood as needed to maintain a MAP of 65 mm Hg. After 90 min, "in-hospital" resuscitation was performed by administering the remaining shed whole blood providing 100% oxygen for 15 min. Upon recovery from surgery, animals were administered their second dose of vehicle or TXA intravenously over 8 h. Tranexamic acid induced an early improvement in neurologic deficit, which was statistically significant compared with vehicle at 24, 48, and 72 h at three doses tested. Analysis of cerebral hemoglobin content and intracerebral lesion progression revealed 100 mg/kg provided the optimal effects for improvement of neuropathology and was continued for determination of adverse treatment effects. We observed no exacerbation of cerebral thrombosis, but TXA treatment caused an increased risk of EEG abnormalities. These results suggest that TXA following polytrauma with concomitant brain injury may provide mild neuroprotective effects by preventing lesion progression

Topics: Animals; Antifibrinolytic Agents; Brain Injuries; Brain Injuries, Traumatic; Electroencephalography; Fibrin; Head Injuries, Penetrating; Hemorrhage; Multiple Trauma; Rats; Rats, Sprague-Dawley; Tranexamic Acid

Early hemorrhagic death is still the main obstacle for the successful treatment of acute promyelocytic leukemia (APL). However, the mechanisms underlying hemostatic perturbations in APL have not been fully elucidated. Here, we report that CD44 on the membrane of APL blasts and NB4 cells ligated bound fibrinogen, resulting in in situ deposition of fibrin and abnormal fibrin distribution. Clots formed by leukemic cells in response to CD44 and fibrinogen interaction exhibited low permeability and resistance to fibrinolysis. Using flow cytometry and confocal microscopy, we found that CD44 was also involved in platelet and leukemic cell adhesion. CD44 bound activated platelets but not resting platelets through interaction with P-selectin. APL cell-coated fibrinogen-activated platelets directly induce enhanced procoagulant activity of platelets. In vivo studies revealed that CD44 knockdown shortened bleeding time, increased the level of fibrinogen, and elevated the number of platelets by approximately twofold in an APL mouse model. Moreover, CD44 expression on leukemic cells in an APL mouse model was not only associated with bleeding complications but was also related to the wound-healing process and the survival time of APL mice. Collectively, our results suggest that CD44 may be a potential intervention target for preventing bleeding complications in APL.

Topics: Animals; Estrone; Fibrin; Fibrinogen; Hemorrhage; Leukemia, Promyelocytic, Acute; Mice

Bioadhesive performance can be compromised due to bleeding. Bleeding increases mortality. Adhesives with hemostatic function are of great significance. A sustainable and robust hemostatic bioadhesive from okra is reported. The adhesive strength reaches around three and six-fold higher than commercial fibrin on pigskin and glass, respectively. The okra gel presents high-pressure resistance and great underwater adhesive strength. In human blood experiments, the okra gel can activate platelets, enhance the adhesion of activated platelets, and release coagulation factors XI and XII. By forming a fast gel layer and closely adhering to the wound, it can quickly stop bleeding in the liver and heart of rabbits and dogs. Meanwhile, okra gel can cause platelet activation at the wound site and further strengthen its hemostatic performance. It is biocompatible, biodegradable, and can promote wound healing and shows potential as a sustainable bioadhesive, especially in the scenario of significant hemorrhage.

Topics: Abelmoschus; Adhesives; Animals; Blood Coagulation Factors; Dogs; Fibrin; Hemorrhage; Hemostatics; Humans; Liver; Rabbits

Enhanced oxidative stress occurs in atrial fibrillation (AF), however its impact on the efficacy and safety of anticoagulation is unknown. We sought to evaluate whether 8-isoprostaglandin F2 (8-isoprostane) levels are associated with clinical outcomes in anticoagulated AF patients.. In a study involving 243 AF patients (median age 69 years), we measured serum 8-isoprostane, along with prothrombotic markers, including plasma fibrin clot permeability, clot lysis time (CLT), endogenous thrombin potential (ETP), von Willebrand factor (VWF), and fibrinolytic proteins. Ischemic cerebrovascular events, major bleeding, and death were recorded during a median follow-up of 53 months while on anticoagulation, largely on non-vitamin K antagonist oral anticoagulants (NOACs).. Increased 8-isoprostane levels partly through altered fibrin clot structure are associated with thromboembolic events despite anticoagulant therapy in AF patients.

Topics: Administration, Oral; Aged; Anticoagulants; Atrial Fibrillation; Dinoprost; Female; Fibrin; Hemorrhage; Humans; Risk Factors; Stroke; Thromboembolism; Thrombosis; von Willebrand Factor

Complement lectin pathway components, in particular mannan-binding lectin (MBL) and MBL-associated serine proteases (MASPs) have been shown to interact with coagulation factors and contribute to clot formation. Here we investigated the role of MBL and MASP-1 in the haemostatic response following mechanical vessel injury in a human microfluidic bleeding model.. We studied haemostasis in a microvascular bleeding model in the presence of human endothelial cells and human whole blood under flow conditions. We monitored incorporation of proteins into the clot with fluorescently labelled antibodies and studied their effects on clot formation, platelet activation, and bleeding time with specific inhibitors. Platelet activation was also studied by flow cytometry.. Upon vessel injury, MBL accumulated at the injury site in a well-defined wall-like structure. MBL showed partial colocalisation with fibrin, and strong colocalisation with von Willebrand factor and (activated) platelets. Flow cytometry ruled out direct binding of MBL to platelets, but confirmed a PAR4- and thrombin-dependent platelet-activating function of MASP-1. Inhibiting MBL during haemostasis reduced platelet activation, while inhibiting MASP-1 reduced platelet activation, fibrin deposition and prolonged bleeding time.. We show in a microvascular human bleeding model that MBL and MASP-1 have important roles in the haemostatic response triggered by mechanical vessel injury: MBL recognises the injury site, while MASP-1 increases fibrin formation, platelet activation and shortens bleeding time. While the complement lectin pathway may be harmful in the context of pathological thrombosis, it appears to be beneficial during the physiological coagulation response by supporting the crucial haemostatic system.

Topics: Blood Coagulation; Complement System Proteins; Endothelial Cells; Fibrin; Hemorrhage; Hemostatics; Humans; Mannose-Binding Lectin; Mannose-Binding Protein-Associated Serine Proteases; Thrombosis

Scanning Electron Microscopy (SEM) is a powerful, high-resolution imaging technique widely used to analyze the structure of fibrin networks. Currently, structural features, such as fiber diameter, length, density, and porosity, are mostly analyzed manually, which is tedious and may introduce user bias. A reliable, automated structural image analysis method would mitigate these drawbacks. We evaluated the performance of DiameterJ (an ImageJ plug-in) for analyzing fibrin fiber diameter by comparing automated DiameterJ outputs with manual diameter measurements in four SEM data sets with different imaging parameters. We also investigated correlations between biophysical fibrin clot properties and diameter, and between clot permeability and DiameterJ-determined clot porosity. Several of the 24 DiameterJ algorithms returned diameter values that highly correlated with and closely matched the values of the manual measurements. However, optimal performance was dependent on the pixel size of the images-best results were obtained for images with a pixel size of 8-10 nm (13-16 pixels/fiber). Larger or smaller pixels resulted in an over- or underestimation of diameter values, respectively. The correlation between clot permeability and DiameterJ-determined clot porosity was modest, likely because it is difficult to establish the correct image depth of field in this analysis. In conclusion, several DiameterJ algorithms (M6, M5, T3) perform well for diameter determination from SEM images, given the appropriate imaging conditions (13-16 pixels/fiber). Determining fibrin clot porosity via DiameterJ is challenging.

Topics: Adult; Blood Coagulation; Female; Fibrin; Hemorrhage; Humans; Microscopy, Electron, Scanning; Plasma; Porosity; Pregnancy; Thrombosis

Pre-existing comorbidities such as obesity or metabolic diseases can adversely affect the clinical outcome of COVID-19. Chronic metabolic disorders are globally on the rise and often a consequence of an unhealthy diet, referred to as a Western Diet. For the first time in the Syrian hamster model, we demonstrate the detrimental impact of a continuous high-fat high-sugar diet on COVID-19 outcome. We observed increased weight loss and lung pathology, such as exudate, vasculitis, hemorrhage, fibrin, and edema, delayed viral clearance and functional lung recovery, and prolonged viral shedding. This was accompanied by an altered, but not significantly different, systemic IL-10 and IL-6 profile, as well as a dysregulated serum lipid response dominated by polyunsaturated fatty acid-containing phosphatidylethanolamine, partially recapitulating cytokine and lipid responses associated with severe human COVID-19. Our data support the hamster model for testing restrictive or targeted diets and immunomodulatory therapies to mediate the adverse effects of metabolic disease on COVID-19.

Topics: Animals; COVID-19; Cricetinae; Cytokines; Diet, High-Fat; Dietary Carbohydrates; Disease Models, Animal; Edema; Fibrin; Hemorrhage; Humans; Interleukin-10; Interleukin-6; Lipid Metabolism; Lipidomics; Lipids; Liver; Lung; Male; Mesocricetus; Obesity; SARS-CoV-2; Severity of Illness Index; Sugars; Vasculitis; Virus Shedding

Topics: Animals; Biocompatible Materials; Bleeding Time; Blood Coagulation; Chitosan; Female; Fibrin; Hemorrhage; Hemostasis; Male; Mice; Oligopeptides; Rats; Rats, Wistar; Thrombin

Current thrombolytic agents activate plasminogen to plasmin which triggers fibrinolysis to dissolve thrombi. Since plasmin is a nonspecific proteolytic enzyme, all of the current plasmin-dependent thrombolytics lead to serious hemorrhagic complications, demanding a new class of fibrinolytic enzymes independent from plasmin activation and undesirable side effects. We speculated that the mammalian version of bacterial heat-shock proteins could selectively degrade intravascular thrombi, a typical example of a highly aggregated protein mixture.. The objective of this study is to identify enzymes that can dissolve intravascular thrombi specifically without affecting fibrinogen and fibronectin so that the wound healing processes remain uninterrupted and tissues are not damaged. In this study, HtrA (high-temperature requirement A) proteins were tested for its specific proteolytic activity on intravascular thrombi independently from plasmin activation.. HtrA1 and HtrA2/Omi proteins, collectively called as HtrAs, lysed ex vivo blood thrombi by degrading fibrin polymers. The thrombolysis by HtrAs was plasmin-independent and specific to vascular thrombi without causing the systemic activation of plasminogen and preventing nonspecific proteolysis of other proteins including fibrinogen and fibronectin. As expected, HtrAs did not disturb clotting and wound healing of excised wounds from mouse skin. It was further confirmed in a tail bleeding and a rebleeding assay that HtrAs allowed normal clotting and maintenance of clot stability in wounds, unlike other thrombolytics. Most importantly, HtrAs completely dissolved blood thrombi in tail thrombosis mice, and the intravenous injection of HtrAs to mice with pulmonary embolism completely dissolved intravascular thrombi and thus rescued thromboembolism.. Here, we identified HtrA1 and HtrA2/Omi as plasmin-independent and highly specific thrombolytics that can dissolve intravascular thrombi specifically without bleeding risk. This work is the first report of a plasmin-independent thrombolytic pathway, providing HtrA1 and HtrA2/Omi as ideal therapeutic candidates for various thrombotic diseases without hemorrhagic complications.

Topics: Animals; Disease Models, Animal; Female; Fibrin; Fibrinolysis; Fibrinolytic Agents; Hemorrhage; High-Temperature Requirement A Serine Peptidase 1; High-Temperature Requirement A Serine Peptidase 2; Humans; Kinetics; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Pulmonary Embolism; Recombinant Proteins; Thrombosis; Wound Healing

We identified a patient with a novel heterozygous variant fibrinogen, γp.C352R (Niigata II; N-II), who had a bleeding episode and failed infertility treatment and was suspected to have hypodysfibrinogenemia based on low and discordant fibrinogen levels (functional assay 0.33 g/L, immunological assay 0.91 g/L). We analyzed the mechanism of this rare phenotype of a congenital fibrinogen disorder.. Patient plasma fibrinogen was purified and protein characterization and thrombin-catalyzed fibrin polymerization performed. Recombinant fibrinogen-producing Chinese hamster ovary (CHO) cells were established and the assembly and secretion of variant fibrinogen analyzed by ELISA and western blotting.. Purified N-II plasma fibrinogen had a small lower molecular weight band below the normal γ-chain and slightly reduced fibrin polymerization. A limited proportion of p.C352R fibrinogen was secreted into the culture medium of established CHO cell lines, but the γ-chain of p.C352R was synthesized and variant fibrinogen was assembled inside the cells.. We demonstrated that fibrinogen N-II, γp.C352R was associated with markedly reduced secretion of variant fibrinogen from CHO cells, that fibrin polymerization of purified plasma fibrinogen was only slightly affected, and that fibrinogen N-II produces hypodysfibrinogenemia in plasma.

Topics: Afibrinogenemia; Alleles; Amino Acid Substitution; Animals; Blood Coagulation; Blood Coagulation Tests; Catalysis; CHO Cells; Cricetulus; Fibrin; Fibrinogen; Hemorrhage; Humans; Infertility; Mutation; Polymerization; Thrombin

Platelets crucially facilitate wound healing but can become depleted in traumatic injury or chronic wounds. Previously, our group developed injectable platelet-like particles (PLPs) comprised of highly deformable, ultralow crosslinked pNIPAm microgels (ULCs) coupled to fibrin binding antibodies to treat post-trauma bleeding. PLP fibrin-binding facilitates homing to sites of injury, promotes clot formation, and, due to high particle deformability, induces clot retraction. Clot retraction augments healing by increasing clot stability, enhancing clot stiffness, and promoting cell migration into the wound bed. Because post-traumatic healing is often complicated by infection, the objective of these studies was to develop antimicrobial nanosilver microgel composite PLPs to augment hemostasis, fight infection, and promote healing post-trauma. A key goal was to maintain particle deformability following silver incorporation to preserve PLP-mediated clot retraction. Clot retraction, antimicrobial activity, hemostasis after trauma, and healing after injury were evaluated via confocal microscopy, colony-forming unit assays, a murine liver trauma model, and a murine full-thickness injury model in the absence or presence of infection, respectively. We found that nanosilver incorporation does not affect base PLP performance while bestowing significant antimicrobial activity and enhancing infected wound healing outcomes. Therefore, Ag-PLPs have great promise for treating hemorrhage and improving healing following trauma.

Topics: Acrylic Resins; Animals; Anti-Infective Agents; Bacterial Infections; Blood Platelets; Clot Retraction; Colony-Forming Units Assay; Fibrin; Gels; Hemorrhage; Hemostasis; Liver; Male; Metal Nanoparticles; Mice; Mice, Inbred C57BL; Microgels; Silver; Wound Healing

Topics: Antifibrinolytic Agents; Blood Coagulation; Fibrin; Fibrinolysin; Fibrinolysis; Hemorrhage; Humans; Randomized Controlled Trials as Topic; Time Factors; Tranexamic Acid; Wounds and Injuries

Understanding the coagulation process is critical to developing treatments for trauma and coagulopathies. Clinical studies on tranexamic acid (TXA) have resulted in mixed reports on its efficacy in improving outcomes in trauma patients. The largest study, CRASH-2, reported that TXA improved outcomes in patients who received treatment prior to 3 hours after the injury, but worsened outcomes in patients who received treatment after 3 hours. No consensus has been reached about the mechanism behind the duality of these results. In this paper we use a computational model for coagulation and fibrinolysis to propose that deficiencies or depletions of key anti-fibrinolytic proteins, specifically antiplasmin, a1-antitrypsin and a2-macroglobulin, can lead to worsened outcomes through urokinase-mediated hyperfibrinolysis.

Topics: alpha 1-Antitrypsin; Antifibrinolytic Agents; Blood Coagulation; Blood Coagulation Disorders; Computer Simulation; Fibrin; Fibrin Clot Lysis Time; Fibrinolysin; Fibrinolysis; Hemorrhage; Humans; Membrane Proteins; Mortality; Pregnancy-Associated alpha 2-Macroglobulins; Thrombin; Tranexamic Acid; Urokinase-Type Plasminogen Activator; Wounds and Injuries

We identified two heterozygous dysfibrinogenemias, Bβp.Gly45Cys (Kyoto VII; K-VII) and Bβp.Arg74Cys (Iida II; I-II). The impairment of polymerization of Bβp.G45C has been well analyzed; however, that of Bβp.R74C has not. Thus, we compared fibrin polymerization between these variants. To determine the structural and functional characterization of purified fibrinogens, we performed immunoblotting analysis, kinetic analyses of fibrinopeptide A and B release, and thrombin- or batroxobin-catalyzed fibrin or fibrin monomer polymerization. Immunoblotting analysis showed that both variant fibrinogens had variant fibrinogen-albumin complexes and variant fibrinogen multimers, and the amounts of fibrinogen-albumin complexes with fibrinogen K-VII was more than with fibrinogen I-II. Moreover, fibrinopeptide B release from fibrinogen K-VII was about 50% of the control, whereas the others were normal. The maximum slopes of polymerization for variant fibrinogens were reduced, but fibrinogen K-VII was reduced more than fibrinogen I-II. The present study demonstrated that both Bβp.G45C and Bβp.R74C variants showed the presence of variant fibrinogen-albumin complexes and variant fibrinogen multimers, and polymerization of Bβp.G45C was impaired more than Bβp.R74C. Our study and several previous reports concerning the clinical phenotype of both variants suggested the risks of bleeding for patients with Bβp.G45C and thrombosis for patients with Bβp.R74C.

Topics: Adult; Afibrinogenemia; Child; Female; Fibrin; Fibrinogen; Genetic Variation; Hemorrhage; Heterozygote; Humans; Male; Molecular Structure; Polymerization; Risk; Thrombosis

The role of vascular endothelium in acute promyelocytic leukaemia (APL) remains unknown. We aimed to investigate the mechanisms by which APL cells interact with endothelial cells (ECs) and to further explore how the endothelium affects bleeding as well as therapeutic interventions.. APL cells and an original APL cell line, NB4 cells, were used for experiments. The effects of leukaemic cells on ECs were analyzed in vitro and in vivo. Moreover, the endothelial barrier function and procoagulant activity were detected. An APL mouse model was established for in vivo studies.. APL cells interacted with ECs via ICAM-1 and VCAM-1 receptors to disrupt endothelial integrity. This binding activated MLCK signaling, resulting in the trans-endothelial passage of protein and red blood cells (RBCs). Combined treatment with asiatic acid or anti-adhesion receptor antibody inhibited the response of ECs to APL cells, thereby preventing APL-associated haemorrhage in vitro and in vivo. Activated ECs exhibited a procoagulant phenotype after phosphatidylserine exposure. Plasma from APL patients formed a thin fibrin network between procoagulant ECs, and this intercellular fibrin decreased the passage of albumin and RBCs. Ex vivo addition of fibrinogen further enhanced this barrier function in a dose-dependent manner.. Endothelial damage induced by leukaemic cell adherence promotes haemorrhaging in APL. Stabilization of ECs, decreasing adhesion receptor expression, and increasing fibrinogen transfusion levels may be a new therapeutic avenue to alleviate this fatal bleeding complication.. National Science Foundation of China (81670128, 81873433).

Topics: Adult; Aged; Animals; Biomarkers; Capillary Permeability; Cell Adhesion; Cell Communication; Cell Line; Disease Models, Animal; Disease Susceptibility; Endothelial Cells; Endothelium, Vascular; Female; Fibrin; Fluorescent Antibody Technique; Hemorrhage; Humans; Intracellular Space; Leukemia, Promyelocytic, Acute; Male; Mice; Middle Aged; Models, Biological

We examined the link between gestational biomarkers and breast cancer in 9169 daughters born into the Child Health and Development Studies from 1959 to 1967. We identified 137 breast cancer cases diagnosed by age 52 as of 2012. Markers of increased risk included higher placental volume and rapid 2nd trimester gestational weight gain. Protective markers were placental hemorrhage and fibrin deposition, indicators of resistance to placental trophoblast invasion. Paradoxically, higher ponderal index at birth was protective suggesting that fetal and placental pathways to breast cancer are multiple and distinct. Results link placental and fetal phenotypes to breast cancer, characterizing some as restrictive and others as permissive markers of tumor development. We found new biomarkers of breast cancer risk that can be mined to discover 'omic correlates in the pregnancy exposome using archived and contemporary pregnancy samples. This line of investigation may discover new pathways to risk and new opportunities for prevention.

Topics: Biomarkers; Breast Neoplasms; California; Child; Child Development; Child Health; Female; Fetal Development; Fibrin; Hemorrhage; Humans; Nuclear Family; Phenotype; Placenta; Pregnancy; Pregnancy Trimester, Second; Risk Factors; Weight Gain

Topics: Aged; Female; Fibrin; Fibrinolysis; Hemorrhage; Humans; Male; Middle Aged; Permeability; Severity of Illness Index

Blood loss remains a major concern during surgery and can increase the morbidity of the intervention. The use of topical haemostatic agents to overcome this issue therefore becomes necessary. Fibrin sealants are promising haemostatic agents due to their capacity to promote coagulation, but their effectiveness and applicability need to be improved. We have compared the haemostatic efficacy of a novel nanostructured fibrin-agarose hydrogel patch, with (c-NFAH) or without cells (a-NFAH), against two commercially available haemostatic agents in a rat model of hepatic resection. Hepatic resections were performed by making short or long incisions (mild or severe model, respectively), and haemostatic agents were applied to evaluate time to haemostasis, presence of haematoma, post-operative adhesions to adjacent tissues, and inflammation factors. We found a significantly higher haemostatic success rate (time to haemostasis) with a-NFAH than with other commercial haemostatic agents. Furthermore, other relevant outcomes investigated were also improved in the a-NFAH group, including no presence of haematoma, lower adhesions, and lower grades of haemorrhage, inflammation, and necrosis in histological analysis. Overall, these findings identify a-NFAH as a promising haemostatic agent in liver resection and likely in a range of surgical procedures.

Topics: Animals; Fibrin; Hemorrhage; Hemostatics; Hydrogels; Inflammation; Liver; Male; Nanostructures; Necrosis; Rats, Wistar; Sepharose

Zeolite is a multifunctional material, which recently exhibited promising prospects in emerging biological and medical applications. This study reported a new bio-inorganic hybrid of zeolite-fibrin clot composite serving as haemostatic agent in haemophilia A. The zeolite-fibrin clot composite promoted haemocompatibility and helped to achieve short clotting time both in vitro (22 ± 3 s vs. >600 s) and in vivo (4.5 min vs. >60 min) compared to control in coagulation factor VIII deficiency bleeding model. Therefore, in situations of surgical operation or accidental injury, this effective and ready-to-use haemostatic agent may provide rapid haemostasis for haemophilia A patients.

Topics: Animals; Biocompatible Materials; Fibrin; Hemophilia A; Hemorrhage; Hemostasis; Hemostatics; Humans; Male; Mice; Zeolites

Improved treatments are needed for hemophilia A and B, bleeding disorders affecting 400 000 people worldwide. We investigated whether targeting protein S could promote hemostasis in hemophilia by rebalancing coagulation. Protein S (PS) is an anticoagulant acting as cofactor for activated protein C and tissue factor pathway inhibitor (TFPI). This dual role makes PS a key regulator of thrombin generation. Here, we report that targeting PS rebalances coagulation in hemophilia. PS gene targeting in hemophilic mice protected them against bleeding, especially when intra-articular. Mechanistically, these mice displayed increased thrombin generation, resistance to activated protein C and TFPI, and improved fibrin network. Blocking PS in plasma of hemophilia patients normalized in vitro thrombin generation. Both PS and TFPIα were detected in hemophilic mice joints. PS and TFPI expression was stronger in the joints of hemophilia A patients than in those of hemophilia B patients when receiving on-demand therapy, for example, during a bleeding episode. In contrast, PS and TFPI expression was decreased in hemophilia A patients receiving prophylaxis with coagulation factor concentrates, comparable to osteoarthritis patients. These results establish PS inhibition as both controller of coagulation and potential therapeutic target in hemophilia. The murine PS silencing RNA approach that we successfully used in hemophilic mice might constitute a new therapeutic concept for hemophilic patients.

Topics: Animals; Blood Coagulation; Calcium-Binding Proteins; Carrier Proteins; Fibrin; Gene Silencing; Hemophilia A; Hemorrhage; Humans; Mice; Mice, Knockout; Thrombin

The transglutaminase factor XIII (FXIII) stabilizes clots against mechanical and biochemical disruption and is essential for hemostasis. In vitro and in vivo models of venous thrombosis demonstrate that FXIII mediates clot size by promoting red blood cell (RBC) retention. However, the key source of FXIII and whether FXIII activity can be reduced to suppress thrombosis without imposing deleterious hemostatic consequences are 2 critical unresolved questions. FXIII is present in multiple compartments, including plasma (FXIII

Topics: Animals; Blood Platelets; Erythrocytes; Factor XIII; Fibrin; Hemorrhage; Mice; Plasma; Thrombin; Thrombosis; Venous Thrombosis

The success of replantation following traumatic amputation is determined by the quality of the vascular anastomoses. The purpose of this study was to assess the vascularity of injured arteries from traumatically amputated digits using arteriographic and histopathological analysis.. 25 amputated digits were included in the study. Crush and avulsion injuries were evaluated according to the Venkatramani classification. The amputated arteries were dissected under a microscope, and the arterial route determined with a transducer. Arteriography using fluoroscopy was evaluated by a radiologist. The area thought to be damaged was dissected and 2-mm slices taken for histopathological examination, and scored using the parameters of fibrin accumulation, oedema, separation, and bleeding.. Arterial flow was observed in 6 of 7 in the avulsion group. In the crush group, arterial flow was observed in 11 of 16 cases. On histopathological examination in all cases there were 2 or more findings of either oedema, fibrin formation, bleeding or hernia. These findings were more common in the crush group then the avulsion group.. The intravascular introduction of radio contrast agents to amputated digit prior to replantation may give further information particularly in avulsion amputations.

Topics: Adult; Amputation, Traumatic; Angiography; Contrast Media; Crush Injuries; Degloving Injuries; Edema; Female; Fibrin; Finger Injuries; Fingers; Fluoroscopy; Hemorrhage; Hernia; Humans; Male; Microscopy; Middle Aged; Prospective Studies; Regional Blood Flow; Triiodobenzoic Acids

Essentials The standard of care (SOC) for treating neonatal bleeding is transfusion of adult blood products. We compared neonatal clots formed with cryoprecipitate (SOC) to two procoagulant therapies. The current SOC resulted in clots with increased stiffness and decreased fibrinolytic properties. Procoagulant therapies may be a viable alternative to SOC treatment for neonatal bleeding. SUMMARY: Background Bleeding is a serious complication of neonates undergoing cardiopulmonary bypass (CPB) and associated with substantial morbidity and mortality. Bleeding is addressed through the transfusion of adult blood products, including platelets and cryoprecipitate. However, significant differences exist between neonatal and adult clotting components, specifically fibrinogen. Our recent ex vivo studies have shown that neonatal fibrinogen does not fully integrate with adult fibrinogen, leading to decreased susceptibility to fibrinolysis. These differences may contribute to ineffective clot formation and/or an increased risk of thrombosis. A need exists to identify more effective and safer methods to promote clotting in neonates. Objectives Procoagulant agents, such as prothrombin complex concentrates (PCCs) and recombinant activated factor VII (rFVIIa), are being used off-label to treat excessive bleeding in neonates after CPB. Because these agents stimulate endogenous fibrin formation, we hypothesize that their addition to post-CPB neonatal plasma will better recapitulate native clot properties than cryoprecipitate. Methods We analyze the structural, mechanical and degradation properties of fibrin matrices formed by neonatal plasma collected after CPB in the presence of an activated four-factor (F) PCC (FEIBA), rFVIIa, or cryoprecipitate using confocal microscopy, atomic force microscopy and a fluidics-based degradation assay. Results The ex vivo addition of FEIBA and rFVIIa to post-CPB neonatal plasma resulted in enhanced clot networks with differences in fibrin alignment, mechanics and degradation properties. Conclusions Our results suggest that these procoagulant agents could be used as an alternative to the transfusion of adult fibrinogen for the treatment of bleeding after CPB in neonates.

Topics: Blood Coagulation; Blood Coagulation Factors; Blood Coagulation Tests; Blood Transfusion; Cardiopulmonary Bypass; Coagulants; Factor VIIa; Fibrin; Fibrinogen; Fibrinolysis; Hemorrhage; Hemostatics; Humans; Infant, Newborn; Neonatology; Recombinant Proteins; Risk

Therapeutic polymers have the potential to improve the standard of care for hemorrhage, or uncontrolled bleeding, as synthetic hemostats. PolySTAT, a fibrin-crosslinking peptide-polymer conjugate, has the capacity to rescue fibrin clot formation and improve survival in a model of acute traumatic bleeding. PolySTAT consists of a synthetic polymer backbone to which targeting fibrin-binding peptides are linked. For translation of PolySTAT, the optimal valency of peptides must be determined. Grafting of fibrin-binding peptides to the poly(hydroxyethyl methacrylate)-based backbone was controlled to produce peptide valencies ranging from 0 to 10 peptides per polymer. PolySTATs with valencies of ≈4 or greater resulted in increased clot firmness, kinetics, and decreased breakdown as measured by thromboelastometry. A valency of ≈4 increased clot firmness 57% and decreased clot breakdown 69% compared to phosphate-buffered saline. This trend was characterized by neutron scattering, which probed the structure of clots formed in the presence of PolySTAT. Finally, PolySTAT with valencies of 4 (100% survival; p = 0.013) and 8 (80% survival; p = 0.063) improved survival compared to an albumin control in a femoral artery injury model (20% survival). This work demonstrates tunability of hemostatic polymers and the ability of in vitro assays to predict in vivo efficacy.

Topics: Animals; Blood Coagulation; Blood Coagulation Tests; Chitosan; Cross-Linking Reagents; Fibrin; Hemorrhage; Hemostasis; Humans; Peptides; Rats; Rats, Sprague-Dawley; Thrombelastography; Thrombosis; Wounds and Injuries

Fine needle aspiration biopsy (FNAB) can cause reactive histopathological changes, commonly including haemorrhage and granulation tissue. The literature describing vascular proliferation after FNAB is sparse. We aimed to describe neovascularisation in thyroid gland specimens as a consequence of FNAB.. We analysed all thyroid histopathological specimens from the Fimlab Laboratories collected between 2010 and 2013 for neovascularisation and distortions in the accompanying tissue. We evaluated HE-stained slides and CD31-, podoplanin-, and Ki-67-immunostained slides.. We observed vascular proliferation in 64 out of 787 specimens (8.1%). In these patients, the mean age was 62 years, 43 were female and 21 were male. Previous FNAB data were available in 49 cases (76.6%). In 51 cases (79.7%), the neovascularisation occupied less than 5% of the thyroid gland area. The vessel dilatation was moderate in 28 cases (43.8%) and low in 20 cases (31.3%). In tumours, neovessels were detected within the tumour and in the surrounding tissue.. Post-FNAB tissue samples include dilated newly formed vessels, which pathologists should differentiate from rare thyroid vascular tumours. The proposed mechanism is a traumatically induced haemorrhage followed by haematoma and thrombosis that resolves by recanalisation. A knowledge of tissue alteration is needed to avoid misdiagnoses.

Topics: Adult; Aged; Aged, 80 and over; Biopsy, Fine-Needle; Cell Proliferation; Edema; Female; Fibrin; Hemangioma; Hemorrhage; Humans; Immunohistochemistry; Male; Middle Aged; Neovascularization, Pathologic; Thyroid Gland

Formation of denser fiber networks has been reported in atrial fibrillation and ischemic stroke. In this longitudinal cohort study, we evaluated whether fibrin clot density may predict thromboembolic and bleeding risk in patients with atrial fibrillation on vitamin K antagonists.. In 236 patients with atrial fibrillation receiving vitamin K antagonists treatment, we measured ex vivo plasma clot permeability (K. During a median follow-up of 4.3 (interquartile range, 3.7-4.8) years, annual rates of ischemic stroke or transient ischemic attack and major bleeds were 2.96% and 3.45%, respectively. In multivariate Cox regression analysis, patients with lower K. This study is the first to show that unfavorable fibrin properties reflected by formation of denser fibrin networks determine, in part, the efficacy and safety of anticoagulation with vitamin K antagonists in patients with atrial fibrillation.

Topics: Aged; Anticoagulants; Atrial Fibrillation; Blood Coagulation; Capillary Permeability; Cohort Studies; Female; Fibrin; Follow-Up Studies; Hemorrhage; Humans; Longitudinal Studies; Male; Middle Aged; Predictive Value of Tests; Stroke; Thrombosis

Perioperative bleeding is a potentially devastating complication in neurosurgical patients, and plasma fibrinogen concentration has been identified as a potential modifiable risk factor for perioperative bleeding. The aim of this study was to evaluate preconditioning with Crotalus atrox venom (Cv-PC) as potential preventive therapy for reducing perioperative hemorrhage in the rodent model of surgical brain injury (SBI). C. atrox venom contains snake venom metalloproteinases that cleave fibrinogen into fibrin split products without inducing clotting. Separately, fibrinogen split products induce fibrinogen production, thereby elevating plasma fibrinogen levels. Thus, the hypothesis was that preconditioning with C. atrox venom will produce fibrinogen spilt products, thereby upregulating fibrinogen levels, ultimately improving perioperative hemostasis during SBI. We observed that Cv-PC SBI animals had significantly reduced intraoperative hemorrhage and postoperative hematoma volumes compared to those of vehicle preconditioned SBI animals. Cv-PC animals were also found to have higher levels of plasma fibrinogen at the time of surgery, with unchanged prothrombin time. Cv-PC studies with fractions of C. atrox venom suggest that snake venom metalloproteinases are largely responsible for the improved hemostasis by Cv-PC. Our findings indicate that Cv-PC increases plasma fibrinogen levels and may provide a promising therapy for reducing perioperative hemorrhage in elective surgeries.

Topics: Animals; Brain Injuries; Crotalus; Disease Models, Animal; Fibrin; Fibrin Fibrinogen Degradation Products; Fibrinogen; Hematoma; Hemorrhage; International Normalized Ratio; Intraoperative Complications; Male; Prothrombin Time; Rats; Rats, Sprague-Dawley; Snake Venoms

Bioactive peptide research has experienced considerable therapeutic interest owing to varied physiological functions, efficacy in excretion, and tolerability of peptides. Colostrum is a rich natural source of bioactive peptides with many properties elucidated such as anti-thrombotic, anti-hypertensive, opioid, immunomodulatory, etc. In this study, a variant peptide derived from β-lactoglobulin from buffalo colostrum was evaluated for the anti-ophidian property by targeting snake venom metalloproteinases. These are responsible for rapid local tissue damages that develop after snakebite such as edema, hemorrhage, myonecrosis, and extracellular matrix degradation. The peptide identified by LC-MS/MS effectively neutralized hemorrhagic activity of the Echis carinatus venom in a dose-dependent manner. Histological examinations revealed that the peptide mitigated basement membrane degradation and accumulation of inflammatory leucocytes at the venom-injected site. Inhibition of proteolytic activity was evidenced in both casein and gelatin zymograms. Also, inhibition of fibrinolytic and fibrinogenolytic activities was seen. The UV-visible spectral study implicated Zn

Topics: Amino Acid Sequence; Animals; Buffaloes; Caseins; Colostrum; Computer Simulation; Edema; Fibrin; Fibrinogen; Hemorrhage; Hydrolysis; Lactoglobulins; Metalloproteases; Mice; Molecular Docking Simulation; Molecular Dynamics Simulation; Oligopeptides; Peptide Fragments; Protease Inhibitors; Protein Conformation; Proteolysis; Skin; Viper Venoms; Viperidae

Resistance of snakes and some other animals to snake envenomation has been attributed to soluble factors present in their tissues. Here we report the isolation of a novel metalloprotease inhibitor from Bothrops alternatus snake serum (named BaltMPI) with high purity, using a four-step chromatographic method. BaltMPI has molecular weights of 60.5 and 42.4kDa, as determined by SDS-PAGE and mass spectrometry, respectively, and pI=5.27. The first 60 amino acids from the N-terminal region of BaltMPI, determined by Edman's degradation, showed high homology (97%) with the snake venom metalloprotease inhibitor (SVMPI) BJ46a and other SVMPIs (78-82%). The chromatographic fractions and purified BaltMPI exhibited anti-hemorrhagic activity against Batroxase and BjussuMP-I. BaltMPI was stable over wide ranges of pH (1, 5, 8, and 9) and temperature (-80, -20, 4, 60, and 100°C), and suppressed the fibrinogenolytic, fibrinolytic, and azocaseinolytic activities of Batroxase. BaltMPI specifically inhibited the activity of metalloproteases, without affecting the activity of serine proteases. Together, our results suggest that BaltMPI and other SVMPIs are promising molecules for the treatment of snake envenomation, in particular that caused by Bothrops sp.

Topics: Amino Acid Sequence; Animals; Bothrops; Caseins; Fibrin; Fibrinogen; Hemorrhage; Metalloendopeptidases; Mice; Protease Inhibitors; Proteolysis

Positively-charged chitosan gauzes stop bleeding from wounds by electrostatically interacting with negatively-charged cell membranes of erythrocytes to cause erythrocyte agglutination and by sealing wounds through tissue adhesion. In the following work, nonwoven chitosan gauze was impregnated with PolySTAT, a synthetic polymer that enhances coagulation by cross-linking fibrin, to generate PolySTAT/chitosan gauzes with improved hemostatic efficacy. When comparing nonwoven chitosan and PolySTAT/chitosan to a commercially-available chitosan-containing gauze (Celox® Rapid), no appreciable differences were observed in fiber size, morphology, and pore size. However, PolySTAT/chitosan demonstrated more rapid blood absorption compared to Celox® Rapid. In a rat model of femoral artery injury, PolySTAT/chitosan gauzes reduced blood loss and improved survival rate compared to non-hemostatic controls and Celox® Rapid. While Celox® Rapid had stronger adherence to tissues compared to PolySTAT/chitosan gauzes, blood loss was greater due to hematoma formation under the Celox® dressing. Animals treated with PolySTAT/chitosan gauzes required less saline infusion to restore and maintain blood pressure above the target blood pressure (60mmHg) while other treatment groups required more saline due to continued bleeding from the wound. These results suggest that PolySTAT/chitosan gauzes are able to improve blood clotting and withstand increasing arterial pressure with the addition of a fibrin cross-linking hemostatic mechanism.. Blood loss remains one of the leading causes of death after traumatic injury in civilian populations and on the battlefield. Advanced biomaterials that interact with blood components and/or accelerate the clotting process to form a hemostatic plug are necessary to staunch bleeding after injury. Chitosan-based gauzes, which stop bleeding by causing red blood cell aggregation, are currently used on the battlefield and have shown variable performance under high pressure arterial blood flow in animal studies, suggesting that red blood cell aggregates require further mechanical stabilization for more reliable performance. In this work, we investigate the binding and cross-linking of fibrin, a major component in blood clots, on chitosan gauze fiber surfaces to structurally reinforce red blood cell aggregates.

Topics: Animals; Arterial Pressure; Bandages; Biopolymers; Blood Coagulation; Cell Adhesion; Chitosan; Cross-Linking Reagents; Disease Models, Animal; Erythrocyte Membrane; Erythrocytes; Femoral Artery; Fibrin; Hemorrhage; Hemostasis; Hemostatics; Polymers; Porosity; Rats

Although many attempts have been made to design advanced hemoglobin-based oxygen carriers (HBOCs), no clinically viable product has been widely approved, because they do not perform normal blood functions, such as coagulation, hematologic reactions and stability. Additionally, the in vivo oxygenation of hemoglobin-loaded nanoparticles (HbPs) encapsulated with polymers has seldom been proved. Herein, HbPs of approximately 200nm with good stability were successfully fabricated and exhibited oxygen-carrying capacity. The HbPs preserve the biological and structure features of hemoglobin according to UV-vis spectrophotometry, Fourier transform infrared (FTIR) spectroscopy and circular dichroism (CD) spectral analysis. In vitro, the HbPs showed a viscosity comparable to that of blood with no obvious effects on red blood cell aggregation. At the same time, blood compatibility was characterized in terms of platelet function, clot strength, speed of clot formation, degree of fibrin cross-linking and hemolysis rate. After intravenous administration of HbPs to mice with controlled hemorrhages, blood flow recovery and maintenance of systemic oxygenation were observed.

Topics: Administration, Intravenous; Animals; Blood Platelets; Blood Substitutes; Cattle; Erythrocyte Aggregation; Fibrin; Hemoglobins; Hemolysis; Hemorrhage; Male; Mice; Mice, Inbred BALB C; Nanoparticles; Oxygen; Particle Size; Rabbits; Rats; Rats, Wistar; Viscosity; Whole Blood Coagulation Time

Essentials Plasma of factor XI-deficient patients (FXI-dp) displays enhanced fibrinolysis. We investigated the role of thrombin activatable fibrinolysis inhibitor (TAFI) in 18 FXI-dp. FXI-dp generated less activated TAFI (TAFIa) on clotting challenge and were resistant to TAFIa. TAFI activation and TAFIa resistance correlated with bleeding score and bleeding phenotype.. Background Factor XI (FXI) deficiency, a rare disorder with unpredictable bleeding, has been associated with reduced fibrinolytic resistance as a result of abnormal fibrin density. Objective We investigated the involvement of thrombin-activatable fibrinolysis inhibitor (TAFI) in the increased lysability of FXI-deficient (FXI-def) clots and the role of thrombin. Patients/Methods Eighteen patients with FXI deficiency (1-58%) and 17 matched controls were investigated for fibrinolytic resistance to t-PA, thrombin generation, TAFI activation and response to TAFIa. Results When clotting was induced by 0.5 pm tissue factor (TF), FXI-def plasmas displayed less thrombin and TAFIa generation and shorter lysis time than controls. A 100-fold higher TF concentration (to bypass FXI) abolished the difference in thrombin generation but not in lysis time between patients and controls. Normalization of FXI levels by a FXI concentrate increased thrombin generation but had no effect on the lysis time of FXI-def plasma. Moreover, when clots were induced by purified thrombin and high concentrations of FXa inhibitor, FXI-def plasma still generated less TAFIa and displayed a shorter lysis time than controls. Finally, upon TAFIa addition, the lysis time of FXI-def plasma was prolonged significantly less than that of control plasma, suggesting a TAFIa resistance. TAFIa generation and TAFIa resistance were correlated with the bleeding score, displaying a considerable capacity to discriminate between patients with and without bleeding. Conclusions TAFI pathway impairment, largely caused by a hitherto unknown TAFIa resistance, appears to be one main cause of decreased fibrinolytic resistance in FXI deficiency and might be clinically useful for assessing the bleeding risk of FXI-def patients.

Topics: Adolescent; Adult; Aged; Blood Coagulation; Case-Control Studies; Child; Child, Preschool; Factor XI; Factor XI Deficiency; Female; Fibrin; Fibrinolysis; Follow-Up Studies; Hemorrhage; Humans; Male; Middle Aged; Phenotype; Thrombin; Thrombolytic Therapy; Thrombomodulin; Thrombosis; Tissue Plasminogen Activator; Young Adult

Victims of trauma often develop impaired blood clot formation (coagulopathy) that contributes to bleeding and mortality. Fibrin polymerization is one critical component of clot formation that can be impacted by post-translational oxidative modifications of fibrinogen after exposure to oxidants. In vitro evidence suggests that Aα-C domain methionine sulfoxide formation, in particular, can induce conformational changes that prevent lateral aggregation of fibrin protofibrils during polymerization. We used mass spectrometry of plasma from trauma patients to find that fibrinogen Aα-C domain methionine sulfoxide content was selectively-increased in patients with coagulopathy vs. those without coagulopathy. This evidence supports a novel linkage between oxidative stress, coagulopathy, and bleeding after injury.

Topics: Adult; Blood Coagulation; Female; Fibrin; Fibrinogen; Hemorrhage; Humans; Male; Methionine; Middle Aged; Oxidative Stress; Thrombosis; Wounds and Injuries

Rivaroxaban is currently used to prevent stroke in patients with atrial fibrillation. Measuring coagulation function may help clinicians to understand the effects of this drug and the associated risk of bleeding.. Rivaroxaban was given to 136 patients with non-valvular atrial fibrillation. Mean age was 74.5±9.0 years (men: 63.2%) and mean CHADS2 score (±SD) was 1.8±1.2. Prothrombin times (PTs) and plasma soluble fibrin (SF) levels were examined in 84 out of 136 patients at baseline and at least 2 weeks thereafter. In 48 patients we were able to collect blood at exact times, namely just before and 3h after rivaroxaban administration, corresponding to the trough and peak concentrations. Mean peak PT in 48 patients was 17.1±3.6s and median peak SF level was 1.46μg/mL. Multiple regression analysis showed that female sex, high brain natriuretic peptide, and high dose were independent factors prolonging the peak PT. Patients with peak PTs ≥20s experienced significantly more bleeding events. Among 29 of 46 patients newly treated with rivaroxaban without any previous anticoagulant, we examined coagulation function at the exact trough and peak times. In 29 patients, peak PT was significantly more prolonged than the baseline or trough PT (p<0.001 for both), whereas trough PT was comparable to the baseline PT. In contrast, both trough and peak SF levels in these newly treated patients were significantly reduced than at baseline (p=0.003 and p<0.001, respectively).. In Japanese patients with non-valvular atrial fibrillation receiving rivaroxaban, a prolonged peak PT (≥20s) could indicate increased risk of bleeding, and both trough and peak SF levels were reduced relative to baseline. PT and SF are both valuable measures of coagulation status in patients receiving rivaroxaban, regardless of prior anticoagulant history.

Topics: Aged; Atrial Fibrillation; Factor Xa Inhibitors; Female; Fibrin; Hemorrhage; Humans; Japan; Male; Middle Aged; Prothrombin Time; Risk; Rivaroxaban; Stroke

Snake venom metalloproteinases (SVMPs) are the most abundant components in snake venoms. They are important in the induction of systemic alterations and local tissue damage after envenomation. CcMP-II, which is a metalloproteinase purified from Cerastes cerastes snake venom, was obtained by a combination of gel filtration, ion-exchange and affinity chromatographies. It was homogeneous on SDS-PAGE, with a molecular mass estimated to 35kDa and presents a pI of 5.6. CcMP-II has an N-terminal sequence of EDRHINLVSVADHRMXTKY, with high levels of homology with those of the members of class P-II of SVMPs, which comprises metalloproteinase and disintegrin-like domains together. This proteinase displayed a fibrinogenolytic and hemorrhagic activities. The proteolytic and hemorrhagic activities of CcMP-II were inhibited by EDTA and 1,10-phenanthroline. However, these activities were not affected by aprotinine and PMSF, suggesting that CcMP-II is a zinc-dependent hemorrhagic metalloproteinase with an α-fibrinogenase activity. The hemorrhagic metalloproteinase CcMP-II was also able to hydrolyze extracellular matrix components, such as type IV collagen and laminin. These results indicate that CcMP-II is implicated in the local and systemic bleeding, contributing thus in the toxicity of C. cerastes venom.

Topics: Amino Acid Sequence; Animals; Caseins; Fibrin; Fibrinogen; Hemorrhage; Metalloproteases; Mice; Viper Venoms; Viperidae

Non-specific hemostatic agents, namely activated prothrombin complex concentrate (aPCC), PCC and recombinant activated factor (F) VII (rFVIIa), can be used, off-label, to reverse the effects of FXa inhibitors in the rare cases of severe hemorrhages, as no approved specific antidote is available. We have evaluated the ability of aPCC, PCC and rFVIIa to reverse apixaban.. Healthy volunteer whole blood was spiked with therapeutic or supra-therapeutic apixaban concentrations and two doses of aPCC, PCC or rFVIIa. Tests performed included a turbidimetry assay for fibrin polymerization kinetics analysis, scanning electron microscopy for fibrin network structure observation, thrombin generation assay (TGA), thromboelastometry, prothrombin time and activated partial thromboplastin time.. aPCC generated a dense clot constituting thin and branched fibers similar to those of a control without apixaban, increased fibrin polymerization velocity and improved quantitative (endogenous thrombin potential and peak height) as well as latency (clotting and lag times) parameters. Adding PCC also improved the fibrin and increased quantitative parameters, but fibrin polymerization kinetics and latency parameters were not corrected. Finally, rFVIIa improved latency parameters but failed to restore the fibrin network structure, fibrin polymerization velocity and quantitative parameters.. aPCC was more effective than PCC or rFVIIa in reversing in vitro the effects of apixaban. aPCC rapidly triggered the development of an apparently normal fibrin network and corrected latency and quantitative parameters, whereas PCC or rFVIIa had only a partial effect.

Topics: Antidotes; Blood Coagulation; Blood Coagulation Factors; Factor VIIa; Factor Xa Inhibitors; Fibrin; Healthy Volunteers; Hemorrhage; Hemostasis; Hemostatics; Humans; Kinetics; Microscopy, Electron, Scanning; Partial Thromboplastin Time; Polymerization; Prothrombin Time; Pyrazoles; Pyridones; Recombinant Proteins; Thrombelastography; Thrombin

We present a silica nanoparticle (SNP) functionalized with polyphosphate (polyP) that accelerates the natural clotting process of the body. SNPs initiate the contact pathway of the blood-clotting system; short-chain polyP accelerates the common pathway by the rapid formation of thrombin, which enhances the overall blood-clotting system, both by accelerating fibrin generation and by facilitating the regulatory anticoagulation mechanisms essential for hemostasis. Analysis of the clotting properties of bare SNPs, bare polyP, and polyP-functionalized SNPs in plasma demonstrated that the attachment of polyP to SNPs to form polyP-SNPs creates a substantially enhanced synergistic effect that lowers clotting time and increases thrombin production at low concentrations. PolyP-SNP even retains its clotting function at ambient temperature. The polyP-SNP system has the potential to significantly improve trauma-treatment protocols and outcomes in hospital and prehospital settings.

Topics: Blood Coagulation; Fibrin; Hemorrhage; Hemostasis; Magnetic Resonance Spectroscopy; Nanoparticles; Particle Size; Polyphosphates; Silicon Dioxide; Spectrophotometry, Atomic; Temperature; Thrombin; Whole Blood Coagulation Time; Zirconium

Blood dilution after transfusion fluids leads to diminished coagulant activity monitored by rotational thromboelastometry, assessing elastic fibrin clot formation, or by thrombin generation testing. We aimed to determine the contributions of blood cells (platelets, red blood cells) and plasma factors (fibrinogen, prothrombin complex concentrate) to fibrin clot formation under conditions of haemodilution in vitro or in vivo.Whole blood or plasma diluted in vitro was supplemented with platelets, red cells, fibrinogen or prothrombin complex concentrate (PCC). Thromboelastometry was measured in whole blood as well as plasma; thrombin generation was determined in parallel. Similar tests were performed with blood from 48 patients, obtained before and after massive fluid infusion during cardiothoracic surgery.Addition of platelets or fibrinogen, in additive and independent ways, reversed the impaired fibrin clot formation (thromboelastometry) in diluted whole blood. In contrast, supplementation of red blood cells or prothrombin complex concentrate was ineffective. Platelets and fibrinogen independently restored clot formation in diluted plasma, resulting in thromboelastometry curves approaching those in whole blood. In whole blood from patients undergoing dilution during surgery, elastic clot formation was determined by both the platelet count and the fibrinogen level. Thrombin generation in diluted (patient) plasma was not changed by fibrinogen, but improved markedly by prothrombin complex concentrate. In conclusion, in dilutional coagulopathy, platelets and fibrinogen, but not red blood cells or vitamin K-dependent coagulation factors, independently determine thromboelastometry parameters measured in whole blood and plasma. Clinical decisions for transfusion based on thromboelastometry should take into account the platelet concentration.

Topics: Aged; Blood Coagulation; Blood Platelets; Cardiopulmonary Bypass; Erythrocytes; Female; Fibrin; Fibrinogen; Hemodilution; Hemorrhage; Humans; Male; Middle Aged; Platelet Count; Prothrombin; Thrombelastography; Thrombin; Transfusion Reaction

The aim of the paper was to perform a chronological assessment of the phenomenon of delayed rupture of the spleen, to assess the phenomenological order about the sub-capsular hematoma transformation to determine the causal relationship with trauma as hypothetical cause of death. 80 cases of blunt trauma with splenic capsular hematoma and subsequent rupture of the spleen were evaluated: 38 had an acute rupture of the spleen, 42 presented a break in days or weeks after the traumatic injury. Time between the traumatic event and delayed rupture of the spleen is within a range of time from one day to more than one month. Data recorded included age, sex, type of trauma, injury severity score, grade of splenic injury, associated intra-abdominal injuries, pathologic specimen evaluation. Immunohistochemical investigation of perisplenic hematoma or laceration was performed utilizing polyclonal antibodies anti-fibrinogen, CD61 and CD68, and showed structural chronological differences of sub-capsular hematoma. Expression of modification and organization of erythrocytes, fibrinogen, platelets and macrophages provides an informative picture of the progression of reparative phenomena associated with sub-capsular hematoma and subsequent delayed splenic rupture. Sub-capsular splenic hematoma dating, which we divided into 4 phases, is representing a task in both clinical practice and forensic pathology.

Topics: Adult; Aged; Aged, 80 and over; Case-Control Studies; Erythrocytes; Female; Fibrin; Fibrinogen; Forensic Pathology; Hematoma; Hemorrhage; Hemosiderin; Humans; Immunohistochemistry; Lacerations; Macrophages; Male; Middle Aged; Monocytes; Platelet Aggregation; Retrospective Studies; Spleen; Splenic Diseases; Splenic Rupture; Staining and Labeling; Time Factors; Wounds, Nonpenetrating

Many types of hemostatic agents have been studied for the effective control of bleeding. In this study, a powdery medical adhesive composed of aldehyded dextran and ε-poly (L-lysine) was used with the recombinant batroxobin. Batroxobin is a venomous component from the snake Bothrops atrox moojeni and catalyzes fibrinogen conversion to form soluble fibrin clots. This research aims to examine the performance of the batroxobin-containing adhesive for hemostasis, and evaluate its potential as a novel hemostatic adhesive. The fibrinogen conversion ability of batroxobin was evaluated by a fibrinogen clotting assay and a whole blood clotting assay. Both experiments demonstrated the effectiveness of the batroxobin-containing adhesive for blood clot formation. Animal experiments were also conducted. After a pricking wound was made in an ICR (imprinting control region) mouse liver, the adhesive and various concentrations of batroxobin were applied. The total amount of blood loss was reduced with increasing concentrations of batroxobin. For excessive bleeding conditions, the femoral artery wound model of SD (Sprague-Dawley) rats was adopted. With higher concentrations of batroxobin, hemostasis was more rapidly achieved. Histological analysis of the liver model also supports the hemostatic effects through fibrin clot formation. In conclusion, batroxobin and medical adhesive effectively facilitate blood coagulation, and could be developed for clinical use.

Topics: Adhesives; Aldehydes; Animals; Bandages; Batroxobin; Blood Coagulation; Bothrops; Dextrans; Femoral Artery; Fibrin; Fibrinogen; Hemorrhage; Hemostasis; Hemostatics; Humans; Liver; Male; Mice; Mice, Inbred ICR; Polylysine; Rats; Rats, Sprague-Dawley; Recombinant Proteins

Here we report the antithrombotic functions of pyrimidinethiol-capped gold nanoparticles (Au_DAPT NPs). They can prolong coagulation parameters when injected intravenously in normal mice. Applied in two typical thrombosis models, mice tail thrombosis and pulmonary thromboembolism, gold NPs can inhibit both thrombosis and improve the survival rates of mice tremendously, without increasing the bleeding risk. The anticoagulant mechanisms include inhibiting the platelet aggregation as well as interfering with thrombin and fibrin generation.

Topics: Animals; Anticoagulants; Blood Coagulation; Blood Platelets; Fibrin; Fibrinolytic Agents; Gold; Hemorrhage; Lung Diseases; Male; Metal Nanoparticles; Mice; Pyrimidines; Rats; Rats, Sprague-Dawley; Sulfhydryl Compounds; Thrombin; Thrombosis; Whole Blood Coagulation Time

Platelet Endothelial Cell Adhesion Molecule 1 (PECAM-1) deficient mice in the FVB/n strain exhibit fatal chronic pulmonary fibrotic disease. The illness occurs in the absence of a detectable pro-inflammatory event. PECAM-1 is vital to the stability of vascular permeability, leukocyte extravasation, clotting of platelets, and clearance of apoptotic cells. We show here that the spontaneous development of fibrotic disease in PECAM-1 deficient FVB/n mice is characterized by early loss of vascular integrity in pulmonary capillaries, resulting in spontaneous microbleeds. Hemosiderin-positive macrophages were found in interstitial spaces and bronchoalveolar lavage (BAL) fluid in relatively healthy animals. We also observed a gradually increasing presence of hemosiderin-positive macrophages and fibrin deposition in the advanced stages of disease, corresponding to the accumulation of collagen, IL-10 expression, and myofibroblasts expressing alpha smooth muscle actin (SMA). Together with the growing evidence that pulmonary microbleeds and coagulation play an active part in human pulmonary fibrosis, this data further supports our hypothesis that PECAM-1 expression is necessary for vascular barrier function control and regulation of homeostasis specifically, in the pulmonary environment.

Topics: Animals; Bleeding Time; Disease Models, Animal; Fibrin; Hemorrhage; Hemosiderin; Interleukin-10; Macrophages, Alveolar; Mice; Mice, Inbred Strains; Myofibroblasts; Platelet Endothelial Cell Adhesion Molecule-1; Pulmonary Fibrosis

Epidemiological, biological and clinical links between periodontal and cardiovascular diseases are now well established. Several human studies have detected bacterial DNA corresponding to periodontal pathogens in cardiovascular samples. Intraplaque hemorrhage has been associated with a higher risk of atherosclerotic plaque rupture, potentially mediated by neutrophil activation. In this study, we hypothesized that plaque composition may be related to periodontal pathogens.. Carotid culprit plaque samples were collected from 157 patients. Macroscopic characterization was performed at the time of collection: presence of blood, lipid core, calcification and fibrosis. Markers of neutrophil activation released by carotid samples were quantified (myeloperoxidase or MPO, cell-free DNA and DNA-MPO complexes). PCR analysis using specific primers for Porphyromonas gingivalis, Aggregatibacter actinomycetemcommitans, Treponema denticola, Prevotella intermedia and Tannerella forsythia was used to detect DNA from periodontal pathogens in carotid tissues. In addition, bacterial lipopolysaccharide (LPS) and Immunoglobulins G against T. forsythia were quantified in atherosclerotic carotid conditioned medium.. Intraplaque hemorrhage was present in 73/157 carotid samples and was associated with neutrophil activation, reflected by the release of MPO, cell-free DNA and MPO-DNA complexes. LPS levels were also linked to intraplaque hemorrhage but not with the neutrophil activation markers. Seventy-three percent of the carotid samples were positive for periodontal bacterial DNA. Furthermore, hemoglobin levels were associated with the detection of T. forsythia and neutrophil activation/inflammation markers.. This study suggests a potential role of periodontal microorganisms, especially T. forsythia, in neutrophil activation within hemorrhagic atherosclerotic carotid plaques.

Topics: Aged; Aged, 80 and over; Antibodies, Bacterial; Bacteroidaceae; Carotid Artery Diseases; Carotid Artery Thrombosis; Dental Plaque; DNA, Bacterial; Endarterectomy, Carotid; Extracellular Traps; Female; Fibrin; Hemorrhage; Humans; Lipids; Male; Middle Aged; Neutrophil Infiltration; Neutrophils; NF-kappa B; Periodontitis; Peroxidase; Plaque, Atherosclerotic; Respiratory Burst

The classical antivenom therapy has appreciably reduced snakebite mortality rate and thus is the only savior drug available. Unfortunately, it considerably fails to shield the viper bite complications like hemorrhage, local tissue degradation and necrosis responsible for severe morbidity. Moreover, the therapy is also tagged with limitations including anaphylaxis, serum sickness and poor availability. Over the last decade, snake venom metalloproteases (SVMPs) are reported to be the primary component responsible for hemorrhage and tissue degradation at bitten site. Thus, antivenom inability to offset viper venom-induced local toxicity has been a basis for an insistent search for SVMP inhibitors. Here we report the inhibitory effect of compound 5d, an apigenin based molecule against SVMPs both in silico and in vivo. Several apigenin analogues are synthesized using multicomponent Ugi reactions. Among them, compound 5d effectively abrogated Echis carinatus (EC) venom-induced local hemorrhage, tissue necrosis and myotoxicity in a dose dependant fashion. The histopathological study further conferred effective inhibition of basement membrane degradation, and accumulation of inflammatory leucocytes at the site of EC venom inoculation. The compound also protected EC venom-induced fibrin and fibrinogen degradation. The molecular docking of compound 5d and bothropasin demonstrated the direct interaction of hydroxyl group of compound with Glu146 present in hydrophobic pocket of active site and does not chelate Zn2+. Hence, it is concluded that compound 5d could be a potent agent in viper bite management.

Topics: Animals; Apigenin; Crotalid Venoms; Fibrin; Fibrinogen; Hemorrhage; Metalloendopeptidases; Metalloproteases; Mice; Molecular Docking Simulation; Snake Bites; Snake Venoms; Viperidae

To test the hypothesis that thrombus-specific tissue plasminogen activator (tPA)-loaded nanocarriers enhance thrombolytic efficacy and attenuate hemorrhagic complications.. A series of pegylated and non-pegylated tPA-loaded liposomes were prepared and their surfaces were decorated with the peptide sequence (CQQHHLGGAKQAGDV) of fibrinogen gamma-chain that binds with GPIIb/IIIa expressed on activated platelets. All formulations were characterized for physical properties, stability and in vitro release profile. The thrombolytic activities of tPA-loaded liposomes were tested by visual end-point detection, fibrin agar-plate and human blood clot-lysis assays. The thrombus-specificity of the peptide-modified-liposomes was evaluated by studying the binding of fluorescent peptide-liposomes with activated platelets. The pharmacokinetic profile and thrombolytic efficacy were evaluated in healthy rats and an inferior vena-cava rat model of thrombosis, respectively.. Both pegylated and non-pegylated peptide-modified-liposomes showed favorable physical characteristics and colloidal stability. Formulations exhibited an initial burst release (40-50% in 30 min) followed by a continuous release of tPA (80-90% in 24 h) in vitro. Encapsulated tPA retained >90% fibrinolytic activity as compared to that of native tPA. Peptide-grafted-liposomes containing tPA demonstrated an affinity to bind with activated platelets. The half-life of tPA was extended from 7 to 103 and 141 min for non-pegylated and pegylated liposomes, respectively. Compared to native tPA, liposomal-tPA caused a 35% increase in clot-lysis, but produced a 4.3-fold less depletion of circulating fibrinogen.. tPA-loaded homing-peptide-grafted-liposomes demonstrate enhanced thrombolytic activity with reduced hemorrhagic risk.

Topics: Animals; Blood Coagulation; Blood Platelets; Chemistry, Pharmaceutical; Drug Carriers; Fibrin; Fibrinogen; Fibrinolytic Agents; Half-Life; Hemorrhage; Humans; Liposomes; Male; Nanoparticles; Peptides; Platelet Glycoprotein GPIIb-IIIa Complex; Rats; Rats, Sprague-Dawley; Thrombolytic Therapy; Thrombosis; Tissue Plasminogen Activator

Complex, interrelated systems exist to maintain the fluidity of the blood in the vascular system while allowing for the rapid formation of a solid blood clot to prevent hemorrhaging subsequent to blood vessel injury. These interrelated systems are collectively referred to as haemostasis. The components involved in the haemostatic mechanism consist of vessel walls, platelets, coagulation factors, inhibitors, and the fibrinolytic system. In the broadest sense, a series of cascades involving coagulation proteins and enzymes, as well as cell surfaces (platelets and endothelial cells), work together to generate thrombin, the key enzyme in coagulation, subsequently leading to the formation of a fibrin clot. However, there also exist direct and indirect inhibitors of thrombin to ensure that clot formation does not go uncontrolled. Once the fibrin clot is formed, the fibrinolytic system ensures that the clot is lysed so that it does not become a pathological complication. Taken together, the systems exist to balance each other and maintain order. The balance of coagulation and fibrinolysis keeps the haemostatic system functioning efficiently.

Topics: Blood Coagulation; Blood Coagulation Factors; Blood Platelets; Fibrin; Fibrinolysis; Hemorrhage; Hemostasis; Humans; Thrombin

Topics: Female; Fibrin; Hemodilution; Hemorrhage; Humans; Male; Thrombin

To assess whether Haemocomplettan(®) (fibrinogen concentrate) or Fibrogammin(®) (Factor XIII concentrate) can be used to manage bleeding complications of antithrombotic treatment, we examined a normal plasma pool spiked with AR-H067637 (thrombin inhibitor) or rivaroxaban (activated factor X-inhibitor), to which one of the concentrates was added. Fibrin network permeability (Ks), images of Scanning Electron Microscopy (SEM) and Clot Lysis Time (CLT) were examined. Both inhibitors increased the Ks levels, which could be fully or partly reversed by Haemocomplettan(®) or Fibrogammin(®) respectively. However, these modified clots with tightened network remained non-resistant to fibrinolysis, shown as unaffected CLT. Tranexamic acid at a very low concentration (0·4 mg/ml) aided the two concentrates to stabilize the clots, where the prolongation of CLT was more pronounced for a lower dose than a higher dose of Haemocomplettan(®) while Fibrogammin(®) brought the greatest delay to CLT out of all additions. These observations were partly supported by SEM images, displaying alterations of fibrin fibre arrangement known to influence fibirinolysis. The in vitro data suggest that Haemocomplettan(®) or Fibrogammin(®) given in combination with a mini dose of tranexamic acid may slow down the natural clearance of fibrin clot by plasmin and thus prevent patients from haemorrhagic complications during antithrombotic therapy.

Topics: Factor XIII; Female; Fibrin; Fibrinogen; Fibrinolysin; Fibrinolysis; Fibrinolytic Agents; Hemorrhage; Humans; Male; Thrombin; Tranexamic Acid

Topics: Adult; Deamino Arginine Vasopressin; Female; Fibrin; Fibrinogen; Hemorrhage; Hemostatics; Humans; Male; Thrombelastography; Treatment Outcome

Hepatic fibrin(ogen) has been noted to occur after acetaminophen (APAP)-induced liver injury in mice. Deficiency in plasminogen activator inhibitor-1 (PAI-1), an endogenous inhibitor of fibrinolysis, increases APAP-induced liver injury in mice. However, the roles of fibrinogen and fibrinolysis in APAP-induced liver injury are not known. We tested the hypothesis that hepatic fibrin(ogen) deposition reduces severity of APAP-induced liver injury. APAP-induced (300 mg/kg) liver injury in mice was accompanied by thrombin generation, consumption of plasma fibrinogen, and deposition of hepatic fibrin. Neither fibrinogen depletion with ancrod nor complete fibrinogen deficiency [via knockout of the fibrinogen alpha chain gene (Fbg(-/-))] affected APAP-induced liver injury. PAI-1 deficiency (PAI-1(-/-)) increased APAP-induced liver injury and hepatic fibrin deposition 6 hours after APAP administration, which was followed by marked hemorrhage at 24 hours. As in PAI-1(-/-) mice, administration of recombinant tissue plasminogen activator (tenecteplase, 5 mg/kg) worsened APAP-induced liver injury and hemorrhage in wild-type mice. In contrast, APAP-induced liver injury was reduced in both plasminogen-deficient mice and in wild-type mice treated with tranexamic acid, an inhibitor of plasminogen activation. Activation of matrix metalloproteinase 9 (MMP-9) paralleled injury, but MMP-9 deficiency did not affect APAP-induced liver injury. The results indicate that fibrin(ogen) does not contribute to development of APAP-induced liver injury and suggest rather that plasminogen activation contributes to APAP-induced liver injury.

Topics: Acetaminophen; Alanine Transaminase; Animals; Antithrombin III; Blood Coagulation; Chemical and Drug Induced Liver Injury; Drug Synergism; Fibrin; Fibrinogen; Fibrinolysis; Hemorrhage; Liver; Male; Matrix Metalloproteinase 9; Mice; Mice, Inbred C57BL; Peptide Hydrolases; Plasminogen Activators; Serpin E2; Thrombin; Tissue Plasminogen Activator

Endothelial cells form the inner lining of vascular networks and maintain blood fluidity by inhibiting blood coagulation and promoting blood clot dissolution (fibrinolysis). Plasmin, the primary fibrinolytic enzyme, is generated by the cleavage of the plasma protein, plasminogen, by its activator, tissue plasminogen activator. This reaction is regulated by plasminogen receptors at the surface of the vascular endothelial cells. Previous studies have identified the plasminogen receptor protein S100A10 as a key regulator of plasmin generation by cancer cells and macrophages. Here we examine the role of S100A10 and its annexin A2 binding partner in endothelial cell function using a homozygous S100A10-null mouse. Compared with wild-type mice, S100A10-null mice displayed increased deposition of fibrin in the vasculature and reduced clearance of batroxobin-induced vascular thrombi, suggesting a role for S100A10 in fibrinolysis in vivo. Compared with wild-type cells, endothelial cells from S100A10-null mice demonstrated a 40% reduction in plasminogen binding and plasmin generation in vitro. Furthermore, S100A10-deficient endothelial cells demonstrated impaired neovascularization of Matrigel plugs in vivo, suggesting a role for S100A10 in angiogenesis. These results establish an important role for S100A10 in the regulation of fibrinolysis and angiogenesis in vivo, suggesting S100A10 plays a critical role in endothelial cell function.

Topics: Animals; Annexin A2; Cells, Cultured; Endothelial Cells; Female; Fibrin; Fibrinolysin; Fibrinolysis; Hemorrhage; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Neovascularization, Physiologic; S100 Proteins

To compare the efficacy of a fibrin preparation supplemented with tranexamic acid (Adhexil) with that of established devices, and to determine whether its effect is limited to the site of application.. Rabbit uterine horns were abraded in nonbleeding and bleeding variants of an established adhesions model. In a separate study, a sidewall excision with approximation of the abraded cecum was added. Animals randomly received Adhexil at both, neither, or either loci.. Laboratory study.. Seventy-two female New Zealand White rabbits (Oryctolagus cuniculus).. Adhexil, Seprafilm or SprayGel and Interceed.. The extent of adhesions was evaluated 13 to 16 days after surgery.. Adhexil reduced adhesions (15 +/- 7%; 15 +/- 4%) compared with controls (74 +/- 13%; 78 +/- 9%) in the bleeding and nonbleeding models, respectively. The reductions resulting from the use of Seprafilm (39 +/- 17%; 34 +/- 14%) or SprayGel (61 +/- 18%; 43 +/- 14%) (n = 4) were not statistically significant. In the bleeding model, Interceed (48 +/- 15%) reduced adhesions only modestly.. In the combined uterine and sidewall model, Adhexil reduced selectively the extent and incidence of adhesions. The absolute and relative performance of Adhexil in an established adhesions model and in the presence of bleeding justifies its further investigation.

Topics: Animals; Disease Models, Animal; Drug Combinations; Drug Evaluation, Preclinical; Female; Fibrin; Hemorrhage; Hyaluronic Acid; Postoperative Hemorrhage; Rabbits; Tissue Adhesions; Tranexamic Acid; Uterine Hemorrhage; Uterus

A girl aged 21 months and a boy aged 3 years both died of hemorrhage from intestinal and mesenteric lacerations due to inflicted blunt abdominal trauma. Histologic examination of sections from the areas of duodenal and mesenteric lacerations confirmed changes of acute injury with hemorrhage, acute inflammatory infiltrates, and surface fibrin deposition. In addition, in both cases, there was also evidence of much longer-standing trauma with mesenteric fibrosis and hemosiderin-containing macrophages (the latter in keeping with previous hemorrhage). In the absence of a history of surgery and local inflammatory disease, these findings suggest that these children had suffered previous abdominal trauma, possibly from similar types of injuries. Scarring of the mesentery and intestine in cases of lethal childhood blunt abdominal trauma may provide evidence of previous similar, significant although sublethal tissue damage. Extensive histologic sampling of abdominal organs and tissues including the mesentery can, therefore, be extremely useful in such cases.

Topics: Cell Proliferation; Child, Preschool; Contusions; Female; Fibrin; Fibroblasts; Fibrosis; Forensic Pathology; Hemorrhage; Hemosiderin; Humans; Infant; Intestines; Macrophages; Male; Mesentery; Neutrophils; Pancreas; Recurrence; Wounds, Nonpenetrating

Patients subjected to haemodilution during surgery are at increased risk of bleeding. We hypothesised that, in the acquired dilutional coagulopathy, insufficient haemostasis is due to either insufficient thrombin generation or insufficient fibrin clot formation. In tissue factor-activated plasmas from patients with coagulation deficiency, we measured time curves of thrombin generation and fibrin clot formation (thromboelastography). Investigated were in study A: 10 patients treated with vitamin K antagonist and five healthy subjects; in study B: 30 patients undergoing cardiopulmonary bypass (CPB) surgery and infused with on average 2,000 ml crystalloids and colloids (no major bleeding); in study C: 58 patients undergoing major general surgery, and transfused with >5,000 ml crystalloids, colloids and red cell concentrates, who experienced major bleeding and were post-transfused with fresh frozen plasma. The treatment with vitamin K antagonist led to a progressive reduction in thrombin generation but not fibrin clot formation. In CPB patients, plasma factor levels post-surgery were 53-60% of normal. This was accompanied by moderate reduction in both haemostatic processes. In plasmas from patients undergoing major surgery, factor levels were 38-41% of normal, and these levels increased after plasma transfusion. Taking preset thresholds for normal thrombin generation and fibrin clot formation, at least one of these processes was low in 88-93% of the patients with (persistent) bleeding, but only in 40-53% of the patients without bleeding. In conclusion, the ability of thrombin generation and fibrin clot formation is independently reduced in acquired dilutional coagulopathy, while minimal levels of both are required for adequate haemostasis.

Topics: Aged; Blood Coagulation; Blood Coagulation Disorders; Blood Loss, Surgical; Blood Transfusion; Crystalloid Solutions; Female; Fibrin; Hemodilution; Hemorrhage; Hemostasis; Humans; Isotonic Solutions; Kinetics; Male; Middle Aged; Perioperative Care; Postoperative Hemorrhage; Thrombin; Vitamin K

We report the isolation and structure-function relationship of a 23kDa metalloproteinase named atroxlysin-I from the venom of the Peruvian Bothrops atrox (Jergón). Atroxlysin is a P-I metalloproteinase and contains 204 residues. Its proteolytic activity towards dimethylcasein is enhanced by Ca2+ but inhibited by EDTA, dithiothreitol, excessive Zn2+ and alpha2-macroglobulin. Unlike other structurally homologous P-I metalloproteinases, atroxlysin-I causes hemorrhages. To examine its hemorrhagic activity mechanistically, we studied its function in vitro and in vivo. It cleaved the Ala14-Leu15 and Tyr16-Leu17 bonds in oxidized insulin B-chain and specifically hydrolyzed the alpha-chains of fibrin(ogen) in a dose- and time-dependent manner. Atroxlysin-I cleaved plasma fibronectin and other extracellular matrix proteins (collagens I and IV) and the triple-helical fragment CB3 of collagen IV, but did not degrade laminin-111. Complementarily, the laminin and collagen binding integrins alpha7beta1 and alpha1beta1 were cleaved by atroxlysin. Even without catalytic activity atroxlysin-I inhibited collagen- and ADP-triggered platelet aggregation.

Topics: Amino Acid Sequence; Animals; Blood Platelets; Blood Vessels; Bothrops; Extracellular Matrix; Fibrin; Fibrinogen; Fibronectins; Hemorrhage; Hemostasis; Humans; Integrins; Macroglobulins; Metalloproteases; Molecular Sequence Data; Snake Venoms; Substrate Specificity

In Venezuela, Bothrops snakes are responsible for more than 80% of all recorded snakebites. This study focuses on the biological and hemostatic characteristics of Bothrops isabelae venom along with its comparative characteristics with two other closely related Bothrops venoms, Bothrops atrox and Bothrops colombiensis. Electrophoretic profiles of crude B. isabelae venom showed protein bands between 14 and 100 kDa with the majority in the range of 14-31 kDa. The molecular exclusion chromatographic profile of this venom contains five fractions (F1-F5). Amidolytic activity evaluation evidenced strong thrombin-like followed by kallikrein-like activities in crude venom and in fractions F1 and F2. The fibrinogenolytic activity of B. isabelae venom at a ratio of 100:1 (fibrinogen/venom) induced a degradation of A alpha and B beta chains at 15 min and 2 h, respectively. At a ratio of 100:10, a total degradation of A alpha and B beta chains at 5 min and of gamma chains at 24 h was apparent. This current study evidences one of rarely reported for Bothrops venoms, which resembles the physiologic effect of plasmin. B. isabelae venom as well as F2 and F3 fractions, contain fibrinolytic activity on fibrin plate of 36, 23.5 and 9.45 mm(2)/microg, respectively using 25 microg of protein. Crude venom and F1 fraction showed gelatinolytic activity. Comparative analysis amongst Venezuelan bothropoid venoms, evidenced that the LD(50) of B. isabelae (5.9 mg/kg) was similar to B. atrox-Puerto Ayacucho 1 (6.1 mg/kg) and B. colombiensis-Caucagua (5.8 mg/kg). B. isabelae venom showed minor hemorrhagic activity, whereas B. atrox-Parguasa (Bolivar state) was the most hemorrhagic. In this study, a relative high thrombin-like activity was observed in B. colombiensis venoms (502-568 mUA/min/mg), and a relative high factor Xa-like activity was found in B. atrox venoms (126-294 mUA/min/mg). Fibrinolytic activity evaluated with 10 microg protein, showed that B. isabelae venom contained higher specific activity (50 mm(2)/microg) than B. colombiensis and B. atrox venoms, which should encourage the isolation of these fibrinolytic molecules to improve the quality of immunotherapy.

Topics: Amidohydrolases; Animals; Blood Coagulation; Bothrops; Crotalid Venoms; Electrophoresis, Polyacrylamide Gel; Fibrin; Fibrinolysis; Fibrinolytic Agents; Gelatin; Hemorrhage; Hemostasis; Lethal Dose 50; Male; Mice; Species Specificity; Venezuela

Recombinant factor VIIa (rFVIIa) has been successfully used in various clinical conditions to treat severe coagulopathy, but its efficacy may be affected by the underlying conditions. We therefore investigated the efficacy of rFVIIa treatment under conditions of hypofibrinogenaemia in a pig model of blunt liver injury.. Severe haemodilution was instigated in four groups of seven anaesthetized pigs. Before inflicting liver injury, animals were assigned to receive either 70 mg kg(-1) fibrinogen (fibrinogen group) or placebo (control group). Thirty seconds after injury, rFVIIa (180 µg kg(-1)) (rFVIIa and fibrinogen+rFVIIa groups) or vehicle (control and fibrinogen groups) was administered. Haemodynamic variables, coagulation parameters, and blood loss were monitored for 2 h. Histology was examined to evaluate the presence of thrombi and the consistency of liver injury.. At the end of the observation period, total blood loss [median (range)] decreased in all intervention groups [fibrinogen: 1275 (1221-1439) ml, P=0.036; rFVIIa: 966 (923-1136) ml, P=0.008; fibrinogen+rFVIIa: 678 (475-756) ml, P=0.008] when compared with control animals [blood loss: 1752 (1735-2221) ml]. The mortality rate in the control group was 100%, whereas only 42% of fibrinogen-substituted animals died (P=0.023). All animals treated with rFVIIa or fibrinogen+rFVIIa (P<0.001) survived and no signs of thromboembolism were observed.. rFVIIa under conditions of hypofibrinogenaemia exhibited a positive impact on coagulation parameters and a reduction in blood loss. These effects were significantly improved after prior substitution with fibrinogen.

Topics: Animals; Blood Coagulation Disorders; Disease Models, Animal; Drug Evaluation, Preclinical; Factor VIIa; Fibrin; Fibrinogen; Hemodilution; Hemodynamics; Hemorrhage; Hemostatics; Liver; Male; Pilot Projects; Prothrombin Time; Recombinant Proteins; Sus scrofa; Thrombelastography; Wounds, Nonpenetrating

Topics: Blood Coagulation; Factor XIII; Fibrin; Hemorrhage; Humans; Intraoperative Complications; Neoplasms; Perioperative Care; Thrombin

To gain insight into the contribution of platelet-dependent thrombin formation in haemostasis and thrombosis, we investigated under flow conditions the haemostatic functions of platelets from a patient with Scott syndrome. Scott platelets are characterised by a diminished platelet-dependent thrombin generation. Thrombin generation was determined by calibrated automated thrombography and flow-based experiments were performed to reveal collagen-mediated platelet activation and fibrin deposition. Our studies indicate that adherent Scott platelets do not differ from control platelets in the formation of stable platelet aggregates under static and flow conditions. While for adherent control platelets a shape change, e.g. balloon formation, and externalisation of phosphatidylserine (PS) is associated with an increase in intracellular calcium concentration, this is not the case for Scott platelets. The calcium-induced morphological changes in control platelets are accompanied with a diminished recruitment of free flowing platelets. Scott platelets, not showing a calcium-induced shape change, also lost the ability to recruit free flowing platelets. These findings rebut the hypothesis that the mild bleeding tendency of Scott syndrome patients is due to a preserved adhesive activity of patient's platelets. Perfusion of tissue factor (TF)-activated control blood over immobilised collagen results in the formation of fibrin fibers that radiate from platelet aggregates. Although platelet aggregates were also observed after perfusion with TF-activated Scott blood, fibrin deposition was not observed. In conclusion, our findings indicate that platelet adhesion and spreading on a collagen matrix in the absence of fibrin formation is sufficient to sustain haemostasis under non-traumatic conditions.

Topics: Blood Coagulation; Blood Coagulation Disorders; Blood Platelets; Calcium; Female; Fibrin; Hemorrhage; Humans; Middle Aged; Platelet Aggregation; Regional Blood Flow; Syndrome; Thrombin; Thromboplastin

Preeclampsia (PE) is a placenta-mediated pregnancy complication that results in high maternal and neonatal mortality and morbidity worldwide. Currently, there is no satisfactory pharmacotherapeutic treatment to stop the PE progression. In this study, we investigated the therapeutic effects of anticoagulant agents, including annexin V, heparin, and a fusion protein of annexin V and hirudin (AND), in a murine PE model induced by intravenous injection of phosphatidylserine/phosphatidylcholine (PS/PC) microvesicles. Compared with the control pregnant animals, the pregnant mice injected with PS/PC presented PE-like symptoms, including elevated systolic blood pressure, proteinuria, and reduction of antithrombin III and blood platelets. However, the PE-like symptoms were significantly alleviated after the PS/PC-injected mice were treated with annexin V, AND, or heparin. Furthermore, fibrin deposition in the placentas in the anticoagulant treated mice was remarkably improved, compared with that in the mice injected with PS/PC alone. The data demonstrate that anticoagulants are effective to prevent the occurrence of PE in the murine model and also suggest that hypercoagulation in the placenta is a contributing factor in the pathogenesis of PE.

Topics: Animals; Annexin A5; Anticoagulants; Antithrombin III; Blood Pressure; Female; Fetal Death; Fetal Weight; Fibrin; Hemorrhage; Heparin; Hirudin Therapy; Hirudins; Intestines; Liposomes; Male; Mice; Mice, Inbred ICR; Organ Size; Phosphatidylcholines; Phosphatidylserines; Placenta; Platelet Count; Pre-Eclampsia; Pregnancy; Proteinuria

Bothrops colombiensis venom from two similar geographical locations were tested for their hemostatic functions and characterized by gel-filtration chromatography and SDS-PAGE electrophoresis. The snakes were from Caucagua and El Guapo towns of the Venezuelan state of Miranda. Fibrino(geno)lytic, procoagulant, hemorrhagic, lethal activities, gel-filtration chromatography and SDS-PAGE profiles were analyzed and compared for both venoms. The highest hemorrhagic activity of 5.3 mug was seen in El Guapo venom while Caucagua venom had the lowest LD(50) of 5.8 mg/kg. Both venoms presented similar thrombin-like activity. El Guapo showed a factor Xa-like activity two times higher than Caucagua. Differences were observed in kallikrein-like and t-PA activities, being highest in El Guapo. Caucagua venom showed the maximum fibrin lysis. Both crude venom runs on Sephadex G-100 chromatography gave fraction SII with the high fibrinolytic activity. Proteases presented in SII fractions and eluted from Benzamidine-Sepharose (not bound to the column) provoked a fast degradation of fibrinogen alpha chains and a slower degradation of beta chains, which could possibly be due to a higher content of alpha fibrinogenases in these venoms. The fibrinogenolytic activity was decreased by metalloprotease inhibitors. The results suggested that metalloproteases in SII fractions were responsible for the fibrinolytic activity. The analysis of samples for fibrin-zymography of SII fractions showed an active band with a molecular mass of approximately 30 kDa. These results reiterate the importance of using pools of venoms for antivenom immunization, to facilitate the neutralization of the maximum potential number of toxins.

Topics: Animals; Blood Coagulation; Bothrops; Chromatography, Gel; Crotalid Venoms; Dextrans; Electrophoresis, Polyacrylamide Gel; Factor Xa; Fibrin; Fibrinogen; Fibrinolysis; Hemorrhage; Humans; Kallikreins; Lethal Dose 50; Metalloproteases; Mice; Molecular Weight; Peptide Hydrolases; Protease Inhibitors; Skin Diseases; Thrombin; Tissue Plasminogen Activator; Venezuela

The annexin A2 (A2) heterotetramer, consisting of two copies of A2 and two copies of S100A10/p11, promotes fibrinolytic activity on the surface of vascular endothelial cells by assembling plasminogen and tissue plasminogen activator (tPA) and accelerating the generation of plasmin. In humans, overexpression of A2 by acute promyelocytic leukemia cells is associated with excessive fibrinolysis and hemorrhage, whereas anti-A2 autoantibodies appear to accentuate the risk of thrombosis in patients with anti-phospholipid syndrome. Complete deficiency of A2 in mice leads to a lack of tPA cofactor activity, accumulation of intravascular fibrin, and failure to clear arterial thrombi. Within the endothelial cell, p11 is required for Src kinase-mediated tyrosine phosphorylation of A2, which signals translocation of both proteins to the cell surface. Here we show that p11 is expressed at very low levels in the absence of A2 both in vitro and in vivo. We demonstrate further that unpartnered p11 becomes polyubiquitinated and degraded via a proteasome-dependent mechanism. A2 stabilizes intracellular p11 through direct binding, thus masking an autonomous p11 polyubiquitination signal that triggers proteasomal degradation. This interaction requires both the p11-binding N-terminal domain of A2 and the C-terminal domain of p11. This mechanism prevents accumulation of free p11 in the endothelial cell and suggests that regulation of tPA-dependent cell surface fibrinolytic activity is precisely tuned to the intracellular level of p11.

Topics: Animals; Annexin A2; Antiphospholipid Syndrome; Autoantibodies; Cell Line, Tumor; Endothelial Cells; Fibrin; Fibrinolysin; Fibrinolysis; Hemorrhage; Humans; Leukemia, Promyelocytic, Acute; Mice; Mice, Knockout; Oncogene Protein pp60(v-src); Proteasome Endopeptidase Complex; Protein Binding; Protein Transport; S100 Proteins; Thrombosis; Tissue Plasminogen Activator; Ubiquitin; Ubiquitination

Various dysfibrinogenemias have been described worldwide. This paper describes two new cases of dysfibrinogenemia identified in the Czech Republic.. The proposita of fibrinogen Nový Jicín, a 12-year-old girl, presented with hemorrhagic complications, low Clauss fibrinogen level (0.3 g/l) and prolonged both thrombin (70.8 s) and reptilase (>180 s) time. Her mother and sister both presented with normal coagulation tests, normal fibrinogen level and reported no history of bleeding. The carriers of the fibrinogen Praha II were a 31-year-old man and his 11-year-old daughter. They both presented with low fibrinogen Clauss level (0.88 g/l) and prolonged thrombin and reptilase time. To identify the genetic mutation responsible for these dysfibrinogens, genomic DNA extracted from the blood was analyzed. The presence of the mutant chains in the circulation was determined by MALDI-TOF mass spectroscopy. Scanning electron micrographs of the patients' fibrin clots were obtained.. The kinetics of fibrinopeptide release and fibrin polymerization were impaired for both fibrinogen Nový Jicín and Praha II. DNA sequencing showed heterogeneous fibrinogen Aalpha R16C mutation in the fibrinogen Nový Jicín case and heterogeneous fibrinogen Aalpha R16H in the fibrinogen Praha II case. The mutant chains were found to be expressed to the circulation by MALDI-TOF mass spectroscopy. Scanning electron micrographs of the patient's fibrin clot were found to be abnormal.. The case of dysfibrinogenemia Aalpha R16C-fibrinogen Nový Jicín and the case of dysfibrinogenemia Aalpha R16H were found by routine coagulation testing and were genetically identified.

Topics: Adult; Afibrinogenemia; Blood Coagulation Tests; Child; Czech Republic; DNA Mutational Analysis; Family Health; Female; Fibrin; Fibrinogens, Abnormal; Hemorrhage; Humans; Kinetics; Male; Mutation, Missense

We report here the antiproteolytic and antihemorrhagic properties of triterpenoid saponin inhibitors, named macrolobin-A and B, from Pentaclethra macroloba, against Bothrops snake venoms. The inhibitors were able to neutralize the hemorrhagic, fibrin(ogen)olytic, and proteolytic activities of class P-I and P-III metalloproteases isolated from B. neuwiedi and B. jararacussu venoms. Clotting and fibrinogenolytic activities induced by snake venoms and isolated thrombin-like enzymes were partially inhibited. Furthermore, the potential use of these inhibitors to complement antivenom therapy as an alternative treatment and/or used as molecular models for development of new therapeutical agents in the treatment of snake bite envenomations needs to be evaluated in future studies.

Topics: Animals; Baccharis; Blood Coagulation; Carbohydrate Sequence; Circular Dichroism; Crotalid Venoms; Fibrin; Fibrinogen; Hemorrhage; Magnetic Resonance Spectroscopy; Male; Mice; Molecular Sequence Data; Phospholipases A; Plant Extracts; Plants; Saponins; Serine Proteinase Inhibitors; Snake Venoms; Spectrophotometry, Ultraviolet; Triterpenes

The recombinant protein SAK-RGD-K2-Hir is characterized by its fibrin-specific properties of plasminogen activation combined with antithrombin and antiplatelet activities. It was previously shown in our in-vitro studies to be a more potent and faster-acting thrombolytic agent compared with standard r-SAK. In order to document the effects of the thrombolytic potential of SAK-RGD-K2-Hir we examined this protein in an electrically induced carotid artery thrombosis model and stasis-induced venous model in rats. In the arterial thrombosis model, a bolus injection of SAK-RGD-K2-Hir was less effective than rt-PA and r-SAK. However, the most effective in the improvement and maintenance of carotid patency and in arterial thrombus mass reduction was SAK-RGD-K2. In contrast, all r-SAK derivatives reduced venous thrombus weight significantly in comparison to r-SAK and r-Hir. However, the most observable decrease in thrombus weight was obtained after application of recombinant proteins containing the r-Hir. The bleeding time was significantly prolonged in the animals treated with proteins containing r-Hir at a dose of 1.0 mg/kg. There were no observable changes in plasma fibrinogen concentration. In conclusion, our findings show thrombolytic activity in intravenous bolus injection of the novel thrombolytic agent SAK-RGD-K2-Hir in rats. Although this protein compares favourably with r-SAK in rat venous thrombolysis, we were unable to confirm the beneficial effects of SAK-RGD-K2-Hir over r-SAK and rt-PA in the carotid artery thrombolysis model. Furthermore, our results also suggest that SAK-RGD-K2-Hir bears a risk of bleeding, but this may be true for higher doses.

Topics: Animals; Bleeding Time; Blood Coagulation; Carotid Artery Thrombosis; Disease Models, Animal; Dose-Response Relationship, Drug; Electric Stimulation; Fibrin; Fibrinolytic Agents; Hemorrhage; Hirudins; Ligation; Male; Metalloendopeptidases; Partial Thromboplastin Time; Rats; Rats, Wistar; Recombinant Fusion Proteins; Thrombin Time; Time Factors; Tissue Plasminogen Activator; Vascular Patency; Venae Cavae; Venous Thrombosis

Urokinase plasminogen activator (uPA) is strongly expressed in atherosclerotic lesions, but the overall effect of the protease on plaque composition and growth remains controversial. In the present study, apolipoprotein E-deficient (apoE(-/-)) mice were intercrossed with mice which were lacking the uPA gene (doubleknockout; DKO). In ferric chloride-induced carotid artery lesions in chow-fed mice, uPA deficiency increased neointimal size (P = 0.015) and luminal stenosis (P = 0.014), while reducing media thickness (P = 0.002). A lack of uPA also increased the size of and the luminal obstruction from atherosclerotic plaques at the coronary and brachiocephalic arteries of apoE(-/-) mice. Plaques were characterised by a higher fibrinogen/fibrin content and a decrease in cellularity and collagen content. When apoE(-/-) and DKO mice were analysed as a single group, a significant correlation was found between the alpha-actin (smooth muscle cell) and collagen content of atherosclerotic lesions (r = 0.554; P < 0.05), and a negative correlation existed between the alpha-actin and fibrin/fibrinogen immunopositive area (r = -0.791; P < 0.001). Further analysis of brachiocephalic atherosclerosis, a predilection site for plaque rupture in the apoE(-/-) mouse, revealed signs of plaque vulnerability, including a reduced cap-to-intima ratio (0.21 +/- 0.04 vs. 0.37 +/- 0.05; P = 0.03) and more frequent detection of intraplaque haemorrhage (56% vs. 13%; P < 0.01) and buried fibrous caps (1.8 +/- 0.5 vs. 0.5 +/- 0.2; P = 0.02) in DKO compared to apoE(-/-) mice. These results indicate that, at least at (patho)physiologic concentrations, uPA is essential for maintaining the cellularity and collagen content and, possibly, the stability of lesions, both by preventing excessive intramural fibrin accumulation and by facilitating cell migration and invasion.

Topics: Animals; Apolipoproteins E; Atherosclerosis; Carotid Artery Diseases; Cell Movement; Collagen; Disease Progression; Fibrin; Hemorrhage; Mice; Mice, Knockout; Urokinase-Type Plasminogen Activator

Acute thrombosis is a threat in patients undergoing percutaneous coronary intervention with stent implantation. Our objective was to determine if stent-induced thrombus formation could be inhibited by oral treatment with a thromboxane A(2)/prostaglandin H(2) receptor antagonist (TPr; S18886) as an alternative to standard therapy. Pigs were allocated in the following treatment (p.o) groups: I) clopidogrel (CLOP); II) ASA; III) S18886; IV) ASA+CLOP; and V) placebo-control. Damaged vessel was placed in the Badimon chamber containing a stent and perfused at 212/s. Antithrombotic effects were assessed as (111)In-platelet deposition (PD) in two series (60 and 180 min after drug intake). Fibrin(ogen) deposition, light transmittance aggregometry (LTA; collagen, U46619, and ADP), and bleeding time (BT) were also evaluated. After 60 min S18886 reduced PD < or =48%, 40%, and 35% vs placebo, CLOP-, and ASA-treated animals, respectively (P < 0.05), while ASA+CLOP showed a 58% reduction versus placebo (P < 0.01). After 3 hours, ASA+CLOP decreased PD by 55%, S18886 by 40%, CLOP alone by 28% (P < 0.05), and ASA showed no inhibition versus placebo. Similar effects were found in S18886- and ASA+CLOP-treated animals at both times. Fibrin(ogen) deposition followed the same pattern. Collagen-induced LTA was significantly reduced by ASA, ASA+CLOP, and S18886; S18886 abolished U46619-induced LTA; and, CLOP +/- ASA reduced ADP-induced LTA in a time-dependent manner. TPr blockade did not prolong BT, whereas CLOP +/- ASA significantly did (P < 0.0001). In conclusion, blockade of the TPr provided a fast and potent platelet inhibitory effect in a porcine model of in-stent thrombosis comparable to that of blocking both the ADP receptor and cyclooxygenase activation; in addition, TPr provided a more favorable bleeding risk profile.

Topics: Administration, Oral; Animals; Aorta; Aspirin; Bleeding Time; Blood Coagulation; Clopidogrel; Disease Models, Animal; Fibrin; Fibrinogen; Fibrinolytic Agents; Hemorrhage; Naphthalenes; Platelet Activation; Platelet Aggregation Inhibitors; Propionates; Prosthesis Design; Receptors, Thromboxane A2, Prostaglandin H2; Stainless Steel; Stents; Swine; Thrombosis; Ticlopidine; Time Factors

In thoracic surgery, although infrequent, we encounter unexpected damage to the pulmonary artery (PA). In the present study, we evaluated the hemostatic efficacy of a newly developed fibrin-based sheet material, thrombin sheet, coupled with liquid fibrinogen (TSF), in an experimental model of PA hemorrhage.. Female beagles (n = 8) were used for the study. Left thoracotomy was performed under general anesthesia. PA injury (approximately 4 x 2 mm) was created, and repaired by TSF (TSF group) or TachoComb (TC group). The animals were allowed to survive, and the repaired site was evaluated 4 weeks after the experiment.. The number of sheet application and compression procedures required for hemostasis was increased in the TC group compared with in the TSF group (TC vs. TSF, 4 +/- 1 vs. 1 +/- 0.5, p = 0.01, unpaired t test). The time required to achieve hemostasis was increased in the TC group compared with in the TSF group (TC vs. TSF, 7 +/- 3 vs. 1 +/- 0.5 minutes, p = 0.01, unpaired t test). The amount of bleeding during the hemostasis procedure was increased in the TC group compared with in the TSF group (TC vs. TSF, 48 +/- 22 vs. 3 +/- 3 g, p = 0.01, unpaired t test). At 4 weeks, rethoracotomy revealed no apparent indication of delayed bleeding, such as intrathoracic hematoma formation or excessive adhesion formation in the vicinity of PA, in either group. Histologically, the vessel lumen was well sustained in both groups, with no apparent stenosis or thrombus formation.. The hemostatic efficacy of TSF was superior to TC in this particular experiment. Single application of TSF was sufficient to achieve hemostasis in all but one animal. Compression time of approximately 1 minute was also very short albeit that the bleeding was from the PA and not an artery. These results were presumably because the adhesion was stronger, faster, and the sheet was more pliable in TSF compared with TC.

Topics: Animals; Bandages; Blood Pressure; Disease Models, Animal; Dogs; Female; Fibrin; Fibrinogen; Hemorrhage; Hemostasis, Surgical; Hemostatics; Lacerations; Polyglycolic Acid; Pulmonary Artery; Recombinant Proteins; Thrombin; Treatment Outcome

Varicella (chickenpox) is one of the most frequent highly infectious diseases in childhood. It is caused by varicella-zoster virus. Lethal complications are rare. Focused on histological findings, we present a case of a sudden unexpected death of an otherwise healthy 18-month-old girl due to varicella-induced pneumonia. The histological and immunohistochemical investigations of the lung tissue revealed typical findings of a varicella pneumonia: haemorrhagic and necrotic nodules, intra-alveolar fibrin, numerous neutrophilic granulocytes, lymphocytes, plasmacells, macrophages, multinucleated giant cells and hyaline membranes. Varicella-related deaths are preventable by vaccine. To prevent complications and lethal outcome of varicella as reported here, the recommendations concerning vaccination against varicella must be taken into account in paediatric practice.

Topics: Adolescent; Chickenpox; Death, Sudden; Female; Fibrin; Forensic Pathology; Hemorrhage; Humans; Lung; Lymphocytes; Macrophages, Alveolar; Necrosis; Neutrophils; Plasma Cells; Pneumonia, Viral

While coagulation often causes pathology during infectious disease, we recently demonstrated that fibrin, a product of the coagulation pathway, performs a critical protective function during acute toxoplasmosis (L. L. Johnson, K. N. Berggren, F. M. Szaba, W. Chen, and S. T. Smiley, J. Exp. Med. 197:801-806, 2003). Here, we investigate the mechanisms regulating the formation of this protective fibrin. Through comparisons of Toxoplasma-infected wild-type and cytokine-deficient mice we dissociate, for the first time, the relative fibrin-regulating capacities of pathogen products, host cytokines, and infection-stimulated hemorrhage. Remarkably, neither the pathogen burden nor hemorrhage is a primary regulator of fibrin levels. Rather, two type 1 cytokines exert dominant and counterregulatory roles: tumor necrosis factor alpha (TNF-alpha), acting via the type 1 TNF-alpha receptor, promotes fibrin deposition, while gamma interferon (IFN-gamma), acting via STAT1 and IFN-gamma receptors expressed on radioresistant cells, suppresses fibrin deposition. These findings have important clinical implications, as they establish that cytokines known to regulate pathological coagulation also dictate levels of protective fibrin deposition. We present a novel model depicting mechanisms by which the immune system can destroy infected tissue while independently restraining hemorrhage and promoting tissue repair through the deliberate deposition of protective fibrin.

Topics: Acute Disease; Animals; Fibrin; Gene Expression Regulation; Hemorrhage; Humans; Interferon-gamma; Mice; Mice, Inbred C57BL; Toxoplasma; Toxoplasmosis; Tumor Necrosis Factor-alpha

We present a method to produce vascular disruptions within rat brain parenchyma that targets single microvessels. We used two-photon microscopy to image vascular architecture, to select a vessel for injury and to measure blood-flow dynamics. We irradiated the vessel with high-fluence, ultrashort laser pulses and achieved three forms of vascular insult. (i) Vessel rupture was induced at the highest optical energies; this provides a model for hemorrhage. (ii) Extravasation of blood components was induced near the lowest energies and was accompanied by maintained flow in the target vessel. (iii) An intravascular clot evolved when an extravasated vessel was further irradiated. Such clots dramatically impaired blood flow in downstream vessels, in which speeds dropped to as low as approximately 10% of baseline values. This demonstrates that a single blockage to a microvessel can lead to local cortical ischemia. Lastly, we show that hemodilution leads to a restoration of flow in secondary downstream vessels.

Topics: Animals; Blood Coagulation; Blood Flow Velocity; Brain Edema; Brain Ischemia; Capillary Permeability; Cerebral Cortex; Dextrans; Disease Models, Animal; Erythrocytes; Fibrin; Fluoresceins; Hemodilution; Hemorrhage; Heparin; Hypoxia, Brain; Lasers; Light; Male; Microcirculation; Microscopy, Confocal; Microtubule-Associated Proteins; Rats; Rats, Sprague-Dawley; Regional Blood Flow; Rupture; Sodium Chloride; Stroke; Tissue Plasminogen Activator; Vimentin

Topics: Adolescent; Afibrinogenemia; Codon, Nonsense; Female; Fibrin; Fibrinogen; Fibrinogens, Abnormal; Hemorrhage; Humans

Fibrinolysis has a critical role in the development of bleeding after insertion of a ventricular assist device (VAD). However, chronically, VAD-mediated fibrinolysis may also diminish thromboembolic events. Management of VADs involves fluid administration. It was hypothesized that the fluid administered could modulate fibrinolysis.. Human plasma was diluted (0% to 30%) with 0.9% NaCl, 5% albumin or Voluven (6% hydroxyethyl-starch [HES], mean molecular weight 130 kD) and exposed to tissue-type plasminogen activator (tPA). Plasma obtained from rabbits just before and after 30% dilution with PentaLyte (6% HES, 220 kD), Voluven or Hextend (6% HES, 450 kD) were exposed to tPA. Thrombelastographic clot strength and onset/rate of fibrinolysis were determined.. In human plasma, 0.9% NaCl significantly decreased clot strength, but either prolonged or maintained the onset of fibrinolysis, with the rate of fibrinolysis significantly increased only at 30% dilution. Five percent albumin significantly decreased clot strength and did not affect the onset of fibrinolysis, but it did decrease the rate of fibrinolysis. Voluven significantly decreased clot strength to the greatest extent compared with the other fluids, and decreased the time of onset of fibrinolysis. Rabbit plasma after hemodilution demonstrated significantly decreased clot strength and decreased time of onset of fibrinolysis as compared with Voluven in human plasma.. Compared with crystalloid or albumin, HES solutions enhance fibrinolysis by decreasing clot strength and decreasing the time of onset of fibrinolysis. Further studies are warranted to determine whether the fluid administered to patients with VADs can impact hemorrhagic and thrombotic morbidity.

Topics: Albumins; alpha-2-Antiplasmin; Animals; Blood Coagulation; Factor XIIIa; Fibrin; Fibrinolysis; Heart-Assist Devices; Hemodilution; Hemorrhage; Humans; Hydroxyethyl Starch Derivatives; Kinetics; Male; Plasma; Rabbits; Sodium Chloride; Thrombosis; Time Factors; Tissue Plasminogen Activator

Acid aspiration causes direct lung damage and secondary inflammatory response involving several cytokines and accumulation of neutrophils. Activated protein C (APC) exhibits antithrombotic and anti-inflammatory properties. We examined the effect and mechanism of pre-treatment APC on acid-aspirated lung injury in rats. Anesthetized rats were instilled intratracheally with normal saline (NS, 2 ml kg(-1)) or hydrochloric acid (HCl, 0.1 N, 2 ml kg(-1)). Thirty minutes before HCl instillation, APC (200 U kg(-1) h(-1)) was infused continuously into the right jugular vein. Animals were ventilated during the experiments. Five hours after HCl or NS instillation, bronchoalveolar lavage fluid (BALF) and lung tissue samples were obtained. Total and differential cell count, absorbance, albumin concentration, concentrations of tumor necrosis factor (TNF)-alpha, interleukin (IL)-6 and cytokine-induced neutrophil chemoattractant (CINC) in BALF, wet and dry weight (W/D) ratio were measured. Platelet count and fibrin degradation product (FDP) in peripheral blood were also measured. HCl instillation markedly increased these values in BALF as well as W/D ratio. APC attenuated the parameters increased by HCl-induced lung injury in rats. However, HCl instillation and APC treatment did not cause significant changes in platelet count and FDP compared with the control. We conclude that APC treatment protected the rats against HCl-induced lung injury and that this action seemed to be due to the anti-inflammatory properties of this protein rather than its anti-coagulant effects.

Topics: Albumins; Animals; Anticoagulants; Cell Count; Cytokines; Fibrin; Hemorrhage; Hydrochloric Acid; Leukocyte Elastase; Lung; Male; Neutrophils; Organ Size; Platelet Count; Pneumonia, Aspiration; Protein C; Pulmonary Alveoli; Rats; Rats, Sprague-Dawley; Respiratory Insufficiency

Bacterial infections are major causes of human mortality. The activation of coagulation pathways leading to the deposition of insoluble fibrin frequently accompanies bacterial infection, and much attention has focused upon the pathological attributes of infection-stimulated fibrin deposition. Nevertheless, here we present conclusive evidence that infection-stimulated fibrin deposition can perform critical protective functions during bacterial infection. Specifically, we demonstrate that coagulation-impaired fibrin(ogen)-deficient mice, in comparison with genetically matched control mice, display increased mortality upon peritoneal infection with the gram-positive facultative intracellular bacterium Listeria monocytogenes. To distinguish effects of fibrinogen from those of fibrin, we treat wild-type mice with warfarin, an anticoagulant that suppresses fibrin formation without impacting fibrinogen levels. Warfarin treatment exacerbates listeriosis, suggesting that fibrin is the key mediator of protection. With regard to the underlying protective mechanisms, we demonstrate that fibrin(ogen) suppresses anemia, reduces hemorrhagic pathology, and limits bacterial growth during listeriosis. Despite confirming a prior report that fibrin(ogen) promotes the peritoneal clearance of the extracellular bacterium Staphylococcal aureus, we demonstrate that fibrin(ogen) plays little role in controlling peritoneal numbers of L. monocytogenes bacteria or the dissemination of L. monocytogenes bacteria from the peritoneal cavity. Rather, fibrin(ogen) primarily limits the growth of these intracellular bacteria within hepatic tissue. While the pathological potential of excessive infection-stimulated fibrin deposition is well appreciated, our findings reveal that fibrin can function protectively, via multiple mechanisms, during bacterial infection.

Topics: Animals; Fibrin; Hemorrhage; Interferon-gamma; Listeria monocytogenes; Listeriosis; Liver; Mice; Mice, Inbred C57BL; Nitric Oxide Synthase; Nitric Oxide Synthase Type II; RNA, Messenger; Tumor Necrosis Factor-alpha

HBOC-201, a bovine polymerized hemoglobin, has been proposed as a novel oxygen-carrying resuscitative fluid for patients with hemorrhagic shock (HS). Herein, we evaluated the hemostatic effects of HBOC-201 in an animal model of HS. A 40% blood loss-controlled hemorrhage and soft tissue injury were performed in 24 invasively monitored Yucatan mini-pigs. Pigs were resuscitated with HBOC-201 (HBOC) or hydroxyethyl starch (HEX), or were not resuscitated (NON) based on cardiac parameters during a 4-h prehospital phase. Afterward, animals received simulated hospital care for 3 days with blood or saline transfusions. Hemostasis measurements included in vivo bleeding time (BT), thromboelastography (TEG), in vitro bleeding time (platelet function; PFA-CT), prothrombin time (PT), and partial thromboplastin time (PTT). Serum lactate was measured and lung sections were evaluated for microthrombi by electron microscopy. During the prehospital phase, BT remained unchanged in the HBOC group. TEG reaction time increased in HBOC pigs during the late prehospital phase and was greater than in NON or HEX pigs at 24 h (P = 0.03). TEG maximum amplitude was similar for the two fluid-resuscitated groups. PFA-CT increased in both resuscitated groups but less with HBOC (P = 0.02) in the prehospital phase; this effect was reversed by 24 h (P = 0.02). In the hospital phase, PT decreased (P < 0.02), whereas PTT increased above baseline (P < 0.01). Lactic acidosis in HBOC and HEX groups was similar. Aspartate aminotransferase was relatively elevated in the HBOC group at 24 h. Electron microscopy showed no evidence of platelet/fibrin clots or microthrombi in any of the animals. Twenty-four-hour group differences mainly reflected the fact that all HEX animals (8/8) received blood transfusions compared with only one HBOC animal (1/8). In swine with HS, HBOC resuscitation induced less thrombopathy than HEX during the prehospital phase. Mild delayed effects on platelet and clot formation during the hospital phase are transient and likely related to fewer blood transfusions. In swine with HS, HBOC resuscitation induced less thrombopathy than HEX during the prehospital phase but more thrombopathy in the hospital phase. The delayed effects on platelet and clot formation during the hospital phase are transient and may be related to the need for fewer blood transfusions.

Topics: Acidosis, Lactic; Animals; Bleeding Time; Blood Coagulation; Blood Platelets; Cattle; Fibrin; Hematocrit; Hemoglobins; Hemorrhage; Hemostasis; Hydrogen-Ion Concentration; Hydroxyethyl Starch Derivatives; Lactates; Lung; Microscopy, Electron; Myocardium; Necrosis; Oxygen; Partial Thromboplastin Time; Polymers; Prothrombin Time; Shock, Hemorrhagic; Sodium Chloride; Swine; Thrombelastography; Time Factors

Recently, a wide variety of bandages have been formulated to attempt to improve the effectiveness of emergency intervention in situations of uncontrolled bleeding. The best of these dressings contain a mixture of human thrombin and fibrinogen. The presence of human components in these bandages, although effective, increases the cost of the dressing and raises questions of availability of raw materials and transmission of pathogens. The purpose of this study was to investigate the efficacy of dressings composed of salmon thrombin and fibrinogen in a swine aortotomy model.. A 4.4-mm aortotomy was produced in the abdominal aorta of 19 anesthetized, splenectomized swine. The United States Army standard field gauze was applied to 8 animals, and the salmon thrombin-fibrin dressing (SFD) was applied to 11 animals. Survival, blood loss, and other parameters were measured over a 60-minute period.. All 11 animals that received the SFD survived the aortotomy injury, and bleeding stopped within 7.5 +/- 1.5 min. Seven of 8 animals in the control group were killed when bleeding continued and blood pressures decreased to the cutoff values as outlined in the animal protocol. Bleeding was significantly less in the SFD group compared with the gauze group (241 +/- 65.3 vs. 932.7 +/- 142.4 mL).. Fibrin dressing using salmon-derived thrombin and fibrinogen is effective in controlling severe, uncontrolled bleeding. This dressing may offer an alternative to dressings composed of human coagulation proteins.

Topics: Animals; Aorta, Abdominal; Bandages; Fibrin; Hemodynamics; Hemorrhage; Hemostatics; Salmon; Swine; Thrombin

Our objective was to compare the efficacy of adjunctive intrapleural fibrinolytic agents (IPFA) (streptokinase, urokinase) on fibrinopurulent stage empyema and chronic stage empyema in children. IPFA were used in 78 pediatric patients with empyema (36 fibrinopurulent stage empyemas, 42 chronic stage empyemas) between December 1994 and September 2002. Pleural biopsy was done for staging in all cases. Streptokinase 250,000 units in 100 ml normal saline (62 patients) or 100,000 units urokinase in 100 ml normal saline (16 patients) was instilled daily into the patient's chest tube, and the tube was clamped for 4 h, followed by suction. This treatment was continued daily for 2-8 days until resolution was demonstrated by chest radiographs and/or computed chest tomography. Success of treatment was 97.2% (complete response 24/36, partial response 11/36) in the fibrinopurulent stage and 9.4% (complete response 2/42, partial response 2/42) in chronic empyema cases. In one patient with fibrinopurulent empyema, the treatment was stopped due to allergic reaction and pleural hemorrhage; this patient died 1 day later in a septic condition. Although an invasive method, the pleural biopsy technique may be an alternative way of more properly staging thoracic empyema in selected children in whom staging based on radiographic and biochemical findings is doubtful. Intrapleural fibrinolytic treatment is an effective and safe therapy of choice and may have significant benefit in most children with fibrinopurulent phase empyema, except for those with bronchopleural fistula. IPFA do not seem to be effective in children with chronic phase empyema.

Topics: Adolescent; Biopsy; Chest Tubes; Child; Child, Preschool; Chronic Disease; Drug Hypersensitivity; Empyema, Pleural; Female; Fibrin; Fibrinolytic Agents; Hemorrhage; Humans; Infant; Male; Pleural Diseases; Staphylococcal Infections; Streptokinase; Suction; Tomography, X-Ray Computed; Treatment Outcome; Urokinase-Type Plasminogen Activator

The features of radiation or chemotherapy cystitis mimicking invasive urothelial cancer are not widely known.. A search of the consultation files from our institution between January 1996 and September 2003 identified 20 patients with bladder biopsies showing cystitis mimicking invasive urothelial cancer.. The mean age at diagnosis was 69 years (range, 40-85 years); 80% were males. Complete history was not available in 1 patient. Seventeen patients had a history of pelvic irradiation (15 prostate cancer and 2 endometrial cancer). Two patients had systemic chemotherapy (1 metastatic colon cancer and 1 mixed connective tissue disease). All patients presented with hematuria. The mean time from radiation and/or chemotherapy to presentation was 27 months (range, 0-84 months). All cases showed epithelial proliferation that mimicked invasive cancer within the lamina propria, with marked proliferation seen in 45% of cases. Mild to moderate nuclear pleomorphism was seen in all cases. A characteristic feature was the presence of pseudoinvasive urothelial nests wrapping around the vessels associated with fibrin deposition. Most cases did not show any mitoses (75%). Ulceration was seen in 39% of cases. All cases showed some degree of hemorrhage, fibrin deposition and fibrin thrombi, fibrosis, and acute and chronic inflammation, with hemosiderin identified in 60% of cases. Edema and vascular congestion were common features (95% and 80%, respectively). Thickened vessels and vascular changes associated with radiation injury were identified in 75% of cases. Seventeen patients were followed for a mean of 9 months (range, 0.25-37 months), and none developed bladder cancer.. Radiation or chemotherapy cystitis can show epithelial proliferations that may be confused with invasive urothelial carcinomas. Other findings characteristic of radiation or chemotherapy cystitis, such as hemorrhage, fibrin, and vascular changes, are often seen in association with the epithelial proliferations and are helpful in distinguishing it from invasive cancer. Pathologists must be aware that these changes may be seen with a remote radiation or chemotherapy history, where this information may not be provided or known at the time of the biopsy evaluation.

Topics: Adult; Aged; Aged, 80 and over; Antineoplastic Agents; Colonic Neoplasms; Cystitis; Diagnosis, Differential; Endometrial Neoplasms; Epithelium; Female; Fibrin; Follow-Up Studies; Hemorrhage; Histocytochemistry; Humans; Male; Middle Aged; Mixed Connective Tissue Disease; Prostatic Neoplasms; Radiation Injuries; Radiotherapy; Thrombosis; Time Factors; Urinary Bladder; Urinary Bladder Neoplasms

An abnormal fibrinogen was identified in a 10-year-old male with a mild bleeding tendency; several years later, the patient developed a thrombotic event. Fibrin polymerization of plasma from the propositus and his mother, as measured by turbidity, was impaired. Plasmin digestion of fibrinogen and thrombin bound to the clot were both normal. The structure of clots from both plasma and purified fibrinogen was characterized by permeability, scanning electron microscopy and rheological measurements. Permeability of patients' clots was abnormal, although some measurements were not reliable because the clots were not mechanically stable. Consistent with these results, the stiffness of patients' clots was decreased approximately two-fold. Electron microscopy revealed that the patients' clots were very heterogeneous in structure. DNA sequencing of the propositus and his mother revealed a new unique point mutation that gives rise to a fibrinogen molecule with a missing amino acid residue at Aalpha-Asn 80. This new mutation, which would disrupt the alpha-helical coiled-coil structure, emphasizes the importance of this part of the molecule for fibrin polymerization and clot structure. This abnormal fibrinogen has been named fibrinogen Caracas VI.

Topics: Asparagine; Child; Fibrin; Fibrinogens, Abnormal; Hemorrhage; Humans; Male; Microscopy, Electron, Scanning; Protein Structure, Secondary; Sequence Deletion

Goodpasture's, or anti-glomerular basement membrane (GBM), disease presents with rapidly progressive glomerulonephritis and lung haemorrhage, and is caused by autoimmunity to the NC1 domain of the alpha3 chain of type IV collagen (alpha3(IV)NC1). This study examines the development of crescentic nephritis and alveolar haemorrhage in a model of Goodpasture's disease, experimental autoimmune glomerulonephritis (EAG), induced in WKY rats by immunization with rat GBM in adjuvant. An increase in circulating anti-GBM antibodies and albuminuria was observed by week 2, which increased further by weeks 3 and 4, while a decrease in creatinine clearance was observed by week 2, which decreased further by weeks 3 and 4. The kidneys of animals with EAG showed linear deposits of IgG on the GBM and a transient glomerular infiltration by CD4+ T cells at week 2. By week 3 there were large deposits of fibrin in Bowman's space, and glomerular infiltration by CD8+ T cells and macrophages, accompanied by focal necrotizing glomerulonephritis with crescent formation. Ultrastructural studies showed glomerular endothelial cell swelling and epithelial cell foot process effacement at week 2. As the lesion progressed, capillary loops became occluded and the mesangium became expanded by mononuclear cells. By week 3 there was detachment of the endothelium from the GBM, and accumulation of fibrin beneath the disrupted endothelial cells and in Bowman's space. Occasional breaks were observed in the continuity of the basement membrane, and cytoplasmic projections from infiltrating mononuclear cells could be seen crossing the capillary wall between the lumen and the crescent. The lungs of animals with EAG showed patchy binding of IgG to the alveolar basement membrane (ABM) at week 2, and infiltration of the interstitium by CD8+ T cells and macrophages by weeks 3 and 4, accompanied by both interstitial and alveolar haemorrhage. Ultrastructural studies showed focal mononuclear cell infiltrates in alveolar walls at week 2. Occasional breaks were observed in the basement membrane and adjacent endothelium by weeks 3 and 4, together with accumulation of surfactant and erythrocytes within the alveolar spaces. This study defines for the first time the relationship between the immunological and pathological events during the evolution of EAG, and provides the basis for further work on the pathogenesis of Goodpasture's disease.

Topics: Animals; Anti-Glomerular Basement Membrane Disease; Antibodies; Autoantibodies; Autoimmune Diseases; Autoimmunity; Basement Membrane; Creatinine; Disease Models, Animal; Fibrin; Glomerulonephritis; Hemorrhage; Kidney Glomerulus; Lung Diseases; Male; Microscopy, Electron; Nephritis; Pulmonary Alveoli; Rats; Rats, Inbred WKY

Polyvalent (Crotalinae) and anticoral (Elapidae) antivenoms produced by Instituto Clodomiro Picado, Costa Rica, were assessed for their ability to neutralize various toxic activities of the venoms of North American snakes of the genera Crotalus, Agkistrodon and Micrurus, in assays involving preincubation of venom and antivenom. When the intraperitoneal route of injection was utilized, polyvalent (Crotalinae) antivenom was effective in the neutralization of the venoms of Crotalus atrox, Crotalus adamanteus, Crotalus viridis viridis, Crotalus horridus atricaudatus, Agkistrodon contortrix contortrix and Agkistrodon piscivorus piscivorus, whereas the venom of Crotalus scutulatus was not neutralized. When the intravenous route was used, results differed depending on the "challenge dose" of venom employed. Polyvalent antivenom neutralized all venoms when mice were challenged with 2 LD(50)s of venom. When 5 LD(50)s were used, antivenom neutralized the venoms of C. atrox, C. adamanteus, C. v. viridis and C. h. atricaudatus, being ineffective in the neutralization of C. scutulatus, A. c. contortrix and A. p. piscivorus. Polyvalent antivenom was effective in the neutralization of hemorrhagic and myotoxic activities of all venoms studied. It also neutralized coagulant activity of C. adamanteus venom, whereas most of the venoms were devoid of clotting activity on plasma in vitro. Moreover, it neutralized defibrinating activity of the only three venoms that induced this effect (i.e. C. adamanteus, A. c. contortrix and A. p. piscivorus). Anticoral (Elapidae) antivenom neutralized lethality induced by the venom of Micrurus fulvius, using either the intravenous or the intraperitoneal routes of injection. Moreover, it neutralized myotoxic effect of this venom as well. It is concluded that polyvalent antivenom neutralizes lethality and other activities of most of the crotaline venoms tested. However, since it is ineffective in neutralizing the lethal effect of C. scutulatus venom, it is suggested that a venom containing presynaptically-active neurotoxic phospholipases A(2) related to "mojave toxin" needs to be introduced in the immunizing mixture in order to increase the neutralizing scope of this product in North America. Anticoral antivenom is highly effective in the neutralization of the venom of M. fulvius.

Topics: Animals; Antivenins; Blood Coagulation; Costa Rica; Crotalid Venoms; Elapid Venoms; Fibrin; Hemolysis; Hemorrhage; Infusions, Intravenous; Injections, Intradermal; Injections, Intramuscular; Injections, Intraperitoneal; Lethal Dose 50; Mice; Neutralization Tests; Snakes; United States

Although hirudin is better than heparin at preventing recurrent ischemia in patients with unstable angina, hirudin produces more bleeding. The purpose of this study was to use a rabbit arterial thrombosis prevention and ear bleeding model to determine whether for equivalent efficacy, melagatran, a synthetic direct thrombin inhibitor, is safer than hirudin. A combination of balloon injury and stasis was used to induce thrombosis in the distal aorta, and patency and blood flow were continuously monitored with ultrasonic flow probes. Rabbits were randomized to melagatran (in total doses of 78-313 nmol kg(-1)), hirudin (in total doses of 18-107 nmol kg(-1)), or saline over 90 min. To assess safety, blood loss from standardized ear incisions was measured. Both melagatran and hirudin produced dose-dependent increases in patency and blood flow. At doses that maintained the highest levels of patency, however, melagatran produced 2-3-fold less bleeding than hirudin. Thus, at maximally effective doses, melagatran causes less bleeding than hirudin in this model. These findings raise the possibility that some direct thrombin inhibitors are safer than others.

Topics: Animals; Arteries; Azetidines; Benzylamines; Dose-Response Relationship, Drug; Fibrin; Fibrinolytic Agents; Glycine; Hemorrhage; Hirudin Therapy; Hirudins; Male; Rabbits; Risk Assessment; Thrombin; Thrombosis

Monocrotaline (MCT) is a pyrrolizidine alkaloid (PA) plant toxin that produces hepatotoxicity in people and animals. Human exposure to PAs occurs through consumption of contaminated grains and herbal remedies. Injection (ip) of MCT in rats produced dose-dependent hepatic parenchymal cell injury that was significant at 200 mg/kg. Injection of 300 mg/kg MCT produced time-dependent hepatotoxicity with significant injury beginning by 12 h after treatment. Histopathologic examination of liver sections revealed coagulative hepatocellular necrosis, widening of sinusoids and hemorrhage in centrilobular regions. MCT-induced damage to central venular endothelial cells (CVECs) and sinusoidal endothelial cells (SECs) in the liver was quantified using immunohistochemical staining and by increased plasma hyaluronic acid concentration. MCT damaged CVECs and SECs in the liver by 8 h after treatment. Extensive endothelial cell injury was restricted to centrilobular regions. To determine if damage to endothelial cells in the liver stimulated activation of the coagulation system, fibrin deposition was quantified using immunohistochemistry. Extensive fibrin deposition occurred in the liver after MCT treatment and was restricted to centrilobular regions. Interestingly, both endothelial cell damage and fibrin deposition preceded the onset of hepatic parenchymal cell injury. These results suggest that endothelial cell damage and fibrin deposition in centrilobular regions of the liver are prominent features of MCT-induced liver injury.

Topics: Animals; Dose-Response Relationship, Drug; Endothelium, Vascular; Fibrin; Fluorescent Antibody Technique, Indirect; Hemorrhage; Hyaluronic Acid; Immunohistochemistry; Liver; Male; Microcirculation; Monocrotaline; Necrosis; Rats; Rats, Sprague-Dawley

Prourokinase (proUK) is a zymogenic plasminogen activator that at pharmacological doses is prone to nonspecific activation to urokinase. This has handicapped therapeutic exploitation of its fibrin-specific physiological properties. To attenuate this susceptibility without compromising specific activation of proUK on a fibrin clot, a Lys300-->His mutation (M5) was developed. M5 had a lower intrinsic activity and, therefore, remained stable in plasma at a 4-fold higher concentration than did proUK. M5 had a higher 2-chain activity and induced more rapid plasminogen activation and fibrin-specific clot lysis in vitro. Sixteen dogs embolized with radiolabeled clots were infused with saline, proUK, tissue plasminogen activator, or M5. The lower intrinsic activity allowed a higher infusion rate with M5, which induced the most rapid and efficient clot lysis (50% clot lysis by approximately 600 microg/kg M5 versus approximately 1200 microg/kg proUK). In association with this, M5 caused neither a significant increase in the primary bleeding time nor secondary bleeding (total blood loss). By contrast, these measurements increased 4-fold and 5-fold, respectively, with proUK and >5-fold and 8-fold, respectively, with tissue plasminogen activator. Clot lysis by M5 and hemostasis were further evaluated in 6 rhesus monkeys. M5 again induced rapid clot lysis without a significant increase in the primary bleeding time, and secondary bleeding did not occur. In conclusion, a site-directed mutation designed to improve the stability of proUK in blood at therapeutic concentrations induced superior clot lysis in vitro and in vivo without causing significant interference with hemostasis.

Topics: Amino Acid Substitution; Animals; Bleeding Time; Blood Coagulation; Disease Models, Animal; Dogs; Drug Evaluation, Preclinical; Drug Stability; Enzyme Activation; Femoral Vein; Fibrin; Fibrinolysis; Hemorrhage; Hemostasis; Humans; Macaca mulatta; Male; Mutagenesis, Site-Directed; Plasma; Plasminogen; Recombinant Proteins; Thrombolytic Therapy; Thrombosis; Tissue Plasminogen Activator; Urokinase-Type Plasminogen Activator

Various topical hemostatic agents or devices have been employed to address the challenges associated with hemorrhage from parenchymal organs during surgery or trauma. Their relative efficacy, however, has not been assessed in a single animal model. The objective of this study was to develop a small animal renal hemorrhage model for comparing hemostatic efficacy of various topical agents, and then to compare fibrin sealant (FS) to an existing standard of care for topical hemostasis. A left heminephrectomy was performed in anesthetized adult male Sprague-Dawley rats. Animals were anticoagulated with 2000 IU/kg heparin IV and various topical hemostatic agents were applied to the injury. Treatment groups included FS applied as a spray; FS applied through a cannula; gelatin sponge (GS) soaked in 1000 IU/mL thrombin solution; GS soaked in 300 IU/mL thrombin; dry GS; and fibrinogen without thrombin applied as a spray. The main endpoints of the study were incidence of hemostasis, blood loss, acute survival trends, and maintenance of mean arterial pressure (MAP). Three treatment groups, the two FS groups and the GS soaked in 1000 IU/mL thrombin, afforded significant hemostasis compared to the controls (P < 0.01). Both FS groups had significantly less blood loss, longer survival times, and maintained higher MAPs than the GS-treated groups. Quantitative dose effects and functional deficiencies in topical hemostatic products could be assessed using this animal model. The study demonstrated that liquid FS was significantly more efficacious than a GS soaked in thrombin for abating hemorrhage from a renal excision in a heparinized rat.

Topics: Administration, Topical; Animals; Disease Models, Animal; Fibrin; Hemorrhage; Hemostatics; Heparin; Kidney Diseases; Male; Nephrectomy; Rats; Rats, Sprague-Dawley; Renal Circulation; Thrombin; Time Factors

Active site-inhibited factor VIIa (FFR-rFVIIa) competes with factor VIIa (FVIIa) for binding to tissue factor (TF) and exerts an anti-thrombotic effect. We report an evaluation of the anti-thrombotic properties of FFR-rFVIIa in a model of thrombosis involving two thrombogenic surfaces. Uncoated glass capillaries or glass capillaries coated with TF were incorporated into an arterioarterial shunt in the rat and the occlusion time (OT) of the shunt was determined. An anti-thrombotic activity of FFR-rFVIIa was shown only on the TF-coated surface: the OT of the shunt was significantly prolonged, from 167 +/- 34 s in control animals to 312 +/- 42 s after i.v. bolus administration of 4 mg/kg FFR-rFVIIa. This OT was similar to those observed with the uncoated shunts in untreated animals (353 +/- 84 s). In vitro preincubation of the TF-coated shunt with FFR-rFVIIa significantly prolonged the OT to 245 +/- 45 s in the absence of detectable amounts of FFR-rFVIIa in the plasma. rFFR-rFVIIa weakly prolonged the tail template bleeding time by a factor of 1.5. This effect was more pronounced in animals pretreated with heparin. The anti-thrombotic and prohaemorrhagic effects of FFR-rFVIIa were totally reversed by administration of an equidose of rFVIIa. These results provide new information on the pharmacological properties of FFR-rFVIIa that will be useful for its clinical development.

Topics: Animals; Bleeding Time; Blood Platelets; Factor VIIa; Fibrin; Fibrinolytic Agents; Hemorrhage; Male; Models, Animal; Rats; Rats, Wistar; Recombinant Proteins; Thromboplastin; Thrombosis

To determine the effect of fibrinogen concentration of dry fibrin bandages on blood loss after grade V liver injury.. Twenty-four pigs were used. Grade V liver injuries were induced and treated with dry fibrin bandages containing 0, 4, 8, or 15 mg fibrinogen/cm2. Animals were monitored for 60 minutes. Blood loss, fluid use, hematological data, and hemostasis were assessed.. Post-treatment blood losses (mean and 95% confidence interval [CI]) were 1,560 mL (356-6,844), 372 mL (65-2,134), 225 mL (51-992), and 127 mL (22-732) in the 0-, 4-, 8-, and 15-mg groups, respectively. Only the 15-mg group had results significantly lower than the 0-mg group (p < 0.05). Blood loss was negatively related to fibrinogen concentration (p < 0.05).. Fibrinogen concentration was inversely related to blood loss after grade V liver injury. The 15-mg formulation was the only one that significantly reduced blood loss.

Topics: Animals; Bandages; Disease Models, Animal; Drug Evaluation, Preclinical; Female; Fibrin; Fibrinogen; Hemoglobins; Hemorrhage; Injury Severity Score; Liver; Partial Thromboplastin Time; Platelet Count; Prothrombin; Swine

Paclitaxel can inhibit vascular smooth muscle proliferation in vitro, and early studies suggest that paclitaxel may be useful in preventing restenosis. Early and late intimal growth and local vascular pathological changes associated with paclitaxel delivered via stents have not been fully explored.. Localized drug delivery was accomplished with balloon-expandable stainless steel stents coated with a cross-linked biodegradable polymer, chondroitin sulfate and gelatin (CSG), containing various doses of paclitaxel. CSG-coated stents with paclitaxel (42.0, 20.2, 8.6, or 1.5 microgram of paclitaxel per stent), CSG-coated stents without paclitaxel, and uncoated stents (without paclitaxel or CSG) were deployed in the iliac arteries of New Zealand White rabbits, which were killed 28 days after implant. Mean neointimal thickness at stent strut sites was reduced 49% (P<0.0003) and 36% (P<0.007) with stents containing 42.0 and 20.2 microgram of paclitaxel per stent, respectively, versus CSG-coated stents without paclitaxel. However, histological findings suggested incomplete healing in the higher-dose (42.0 and 20.2 microgram) paclitaxel-containing stents consisting of persistent intimal fibrin deposition, intraintimal hemorrhage, and increased intimal and adventitial inflammation. Stents coated with CSG alone (without paclitaxel) had similar neointimal growth as uncoated stents. In a separate group of rabbits killed at 90 days, neointimal growth was no longer suppressed by CSG-coated stents containing 42.0 or 21.0 microgram of paclitaxel. CSG coating appears to be a promising medium for localized drug delivery. Paclitaxel polymer-coated stents reduce neointima formation but are associated with evidence of incomplete healing at 28 days. However, neointimal suppression was not maintained at 90 days.

Topics: Angiogenesis Inhibitors; Animals; Cell Division; Chondroitin Sulfates; Dose-Response Relationship, Drug; Drug Delivery Systems; Fibrin; Gelatin; Hemorrhage; Iliac Artery; Inflammation; Male; Paclitaxel; Polymers; Rabbits; Stents; Time Factors; Tunica Intima

From the venom of Trimeresurus jerdonii, a distinct thrombin-like enzyme, called jerdonobin, was purified by DEAE A-25 ion-exchange chromatography, Sephadex G-75 gel filtration, and fast protein liquid chromatography (FPLC). SDS-PAGE analysis of this enzyme shows that it consists of a single polypeptide chain with a molecular weight of 38,000. The NH(2)-terminal amino acid sequence of jerdonobin has great homology with venom thrombin-like enzymes documented. Jerdonobin is able to hydrolyze several chromogenic substrates. The enzyme directly clots fibrinogen with an activity of 217 NIH units/mg. The fibrinopeptides released, identified by HPLC, consisted of fibrinopeptide A and a small amount of fibrinopepide B. The activities of the enzyme were inhibited by phenylmethylsulfonyl fluoride (PMSF) and p-nitrophenyl-p-guanidinobenzoate (NPGB). However, metal chelator (EDTA) had no effect on it, indicating it is venom serine protease.

Topics: Amino Acid Sequence; Animals; Blood Coagulation; Chromatography, High Pressure Liquid; Crotalid Venoms; Electrophoresis, Polyacrylamide Gel; Factor XIII; Fibrin; Fibrinogen; Hemorrhage; Mice; Molecular Sequence Data; Molecular Weight; Platelet Aggregation; Serine Endopeptidases; Serine Proteinase Inhibitors; Spectrophotometry, Ultraviolet; Substrate Specificity; Thrombin; Trimeresurus

Topics: Acute Disease; Animals; Antithrombin III; Blood Coagulation Disorders; Complement Activation; Cytokines; Disseminated Intravascular Coagulation; Endotoxemia; Fibrin; Gene Expression Regulation; Hemorrhage; Humans; Lipoproteins; Lung Injury; Primates; Protein C; Reactive Oxygen Species; Respiratory Distress Syndrome; Sepsis; Thromboplastin; Transcription, Genetic; Tumor Necrosis Factor-alpha

The bleeding syndrome of acute promyelocytic leukemia (APL) is complex and consists of disseminated intravascular coagulation (DIC) and hyperfibrinolysis. Elastase, derived from malignant promyelocytes, is believed to mediate the fibrinogeno- and fibrinolysis by aspecific proteolysis. In this study we measured the role of elastase in fifteen patients with APL by using an assay for elastase degraded fibrin(ogen) and the results were compared with those obtained in patients with sepsis induced DIC. High levels of elastase were observed in sepsis and APL. The levels of fibrinogen and fibrin degradation products were significantly higher in APL patients compared to patients with sepsis induced DIC. Nevertheless, the level of elastase degraded fibrin(ogen) was higher in the sepsis group (635.3 ng/ml, compared to 144.3 ng/ml in APL; p <0.0001). So, the enormous increase in fibrin and fibrinogen degradation products in APL cannot be explained by elastase activity. This study suggests a minor role for elastase mediated proteolysis in the hemorrhagic diathesis in APL patients.

Topics: Adult; Aged; Aged, 80 and over; Antibodies, Monoclonal; Blood Coagulation Tests; Disease Susceptibility; Disseminated Intravascular Coagulation; Female; Fibrin; Fibrin Fibrinogen Degradation Products; Fibrinogen; Fibrinolysis; Hemorrhage; Humans; Leukemia, Promyelocytic, Acute; Male; Middle Aged; Neoplasm Proteins; Pancreatic Elastase; Sepsis

Fibrin(ogen) is the major matrix ligand for beta3 integrins. If alpha(v)beta3 is the major receptor for fibrin(ogen) on intimal smooth muscle cells, we might expect to see this integrin associated with fibrin(ogen). Eighty-four specimens obtained from endarterectomies of 14 patients were studied. Fibrin was frequently observed in carotid intima even at the non-atherosclerotic areas. As for beta1 and beta3 integrins, beta1 was predominant in intima. The alpha(v)beta3 integrin expression was less frequent than alpha5beta1, another receptor for fibrin(ogen), in diffuse intimal thickening, fibrous cap and advanced plaques. Furthermore, alpha(v)beta3 was generally negative on smooth muscle cells in recent plaque ruptures. In conclusion, we suggest more attention should be paid on abundant fibrin matrix in intima. Histologically, the alpha5beta1 integrin rather than the alpha(v)beta3 is the major receptor for fibrin in intimal smooth muscle cells.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Antibodies, Monoclonal; Antibody Specificity; Blotting, Western; Carotid Arteries; Carotid Artery Injuries; Carotid Stenosis; Endarterectomy, Carotid; Fibrin; Fibrinogen; Hemorrhage; Humans; Immunohistochemistry; Integrins; Ligands; Male; Middle Aged; Muscle, Smooth, Vascular; Receptors, Fibronectin; Receptors, Vitronectin; Thromboplastin; Tunica Intima

The zinc endopeptidases mutalysin I (100 kDa) and mutalysin II (22.5 kDa) have been previously isolated from bushmaster (Lachesis muta muta) snake venom. Hemorrhagic activity was observed with as little as 0.5 microg (2000 units/mg) and 17.8 microg (56.2 units/mg) for mutalysin I and II, respectively. Additionally, the proteases hydrolyse the Aalpha>Bbeta chain of fibrinogen without clot formation. The specific fibrinogenolytic activity was estimated as 5. 25 and 16.3 micromol fibrinogen/min/micromol protein for mutalysin I and II, respectively. In vitro, the enzymes act directly on fibrin and are not inhibited by serine proteinase inhibitors (SERPINS). Analysis by SDS-PAGE of fibrin hydrolysis by both enzymes showed that mutalysin II (0.22 microM) completely digested the alpha- and gamma-gamma chains and partially the beta-chain (in 120 min incubation). In contrast, mutalysin I (three fold higher concentration than mutalysin II) hydrolyzed selectively the alpha-chain of fibrin leaving the beta and gamma-gamma chains unaffected. Unlike with the plasminogen activator-based thrombolytic agents (e.g., streptokinase), mutalysins do not activate plasminogen. Neither enzyme had an effect on protein C activation. Mutalysin II does not inhibit platelet aggregation in human PRP induced by collagen or ADP. However, mutalysin I showed a selective inhibitory effect on collagen-induced aggregation of human PRP; it did not affect platelet aggregation with ADP as the agonist. The present investigation demonstrates that both native and EDTA-inactivated mutalysin I dose dependently blocked aggregation of human PRP elicited by 10 microg/mL of collagen with an IC(50) of 180 and 580 nM, respectively. These studies suggest that, in addition to the metalloprotease region of mutalysin I, the disintegrin-like domain also participates in the inhibitory effect. The proteolytic activity of mutalysin II against dimethylcasein and fibrin was completely abolished by alpha2-macroglobulin (alpha2-M). The stoichiometry of inhibition was 1.0 mol of enzyme per mol of alpha2-M. In contrast, the proteolytic effect of mutalysin I against the same substrates was not significantly inhibited by alpha2-M. Therefore, the data explain why mutalysin I contributes significantly not only to local but also to systemic bleeding associated with the observed pathological effects of the venom.

Topics: alpha-Macroglobulins; Animals; Enzyme Inhibitors; Fibrin; Fibrin Fibrinogen Degradation Products; Fibrinogen; Fibrinolysis; Hemorrhage; Hemostasis; Humans; Metalloendopeptidases; Plasminogen; Platelet Aggregation; Platelet Function Tests; Protein C; Protein Structure, Tertiary; Rabbits; Viper Venoms

The plasma concentration of soluble adhesion receptors is increased under pathological circumstances, but their function remains enigmatic. Soluble P-selectin (sP-sel) is shed from activated platelets and endothelial cells. Mice genetically engineered to express P-selectin without the cytoplasmic tail (DeltaCT) constitutively show a 3- to 4-fold increase of sP-sel in plasma. We observed that the DeltaCT mice formed fibrin very readily. In an ex vivo perfusion chamber, there was more fibrin deposited at the site of platelet thrombus formation than in wild type (WT), whereas no fibrin deposits were detected using P-selectin-deficient blood during the same interval. Similarly, in vivo, the hemorrhage produced by local Shwartzman reaction was smaller in the DeltaCT mice than in WT. In contrast, we previously showed hemorrhage to be more prominent in P-selectin knock-out mice. Infusion of mouse P-sel-Ig chimera produced the same protective effect in WT mice as seen in the DeltaCT mice, indicating that the effect was due to increased levels of sP-sel. Mice infused with P-sel-Ig showed significantly more fibrin deposited on the luminal face of the injured vessels than control mice. Plasma from DeltaCT mice or mice infused with P-sel-Ig contained higher concentration of pro-coagulant microparticles and clotted one minute faster than WT. This pro-coagulant phenotype of DeltaCT mice could be reversed by a 4-day treatment with PSGL-Ig, a P-selectin inhibitor. We propose that sP-sel should no longer be considered only as a marker of inflammation or platelet activation, but also as a direct inducer of pro-coagulant activity associated with vascular and thrombotic diseases.

Topics: Animals; Blood Coagulation; Fibrin; Hemorrhage; Mice; Mice, Inbred C57BL; Mice, Knockout; P-Selectin; Thrombosis

Structure and content of atherosclerotic plaque varies between patients and may be indicative of their risk for embolisation. This study aimed to construct parametric images of B-scan texture and assess their potential for predicting plaque morphology. Sequential transverse in vitro scans of 10 carotid plaques, excised during endarterectomy, were compared with macrohistology maps of plaque content. Multidiscriminant analysis combined the output of 157 statistical and textural algorithms into five separate texture classes, displayed as ultrasound (US) texture classification images (UTCI). Visual comparison between corresponding UTCI and histology maps found the five texture classes matched with the location of fibrin, elastin, calcium, haemorrhage or lipid. However, histology preparation removes calcium and lipid and, so, can affect the structural integrity of atherosclerotic plaques. Soft tissue regions smaller than the UTCI kernel, (0.87 mm x 0.85 mm x 3.9 mm), such as blood clots, are also difficult to detect by UTCI. These factors demonstrate limitations in the use of histology as a "gold standard" for US tissue characterisation.

Topics: Arteriosclerosis; Calcium; Carotid Arteries; Carotid Stenosis; Elastin; Endarterectomy, Carotid; Fibrin; Hemorrhage; Humans; Image Processing, Computer-Assisted; In Vitro Techniques; Lipids; Ultrasonography

We conducted this study to determine whether the dry fibrin sealant dressing (DFSD) would stop bleeding from a grade V liver injury and to evaluate the effects of leaving the absorbable DFSD in survival animals.. Twenty-four swine (40+/-3.0 kg) received a uniform grade V liver injury and were randomized to one of four 1-hour treatment groups: (1) gauze packing, (2) DFSD, (3) immunoglobulin G placebo dressing, and (4) no treatment. All animals were resuscitated with lactated Ringer's solution. Total blood loss (TBL), mean arterial pressure, resuscitation volume, and laboratory data were monitored for 1 hour after injury. Four swine were treated with the DFSD after grade V injury and allowed to survive for 7 or 14 days.. The TBL was 1,104+/-264 mL (mean +/- SEM), 544+/-104 mL, 4,223+/-1,555 mL, and 6,026+/-1,020 mL for groups 1, 2, 3, and 4 respectively. TBL in DFSD animals was less than that in animals treated with gauze packing (p = 0.06). Grade V injuries were uniform among the 1-hour groups, and no evidence of intrahepatic abscess, unusual adhesions, or hepatic vein, vena caval, or pulmonary thromboses were noted in the long-term survival animals.. In this model of grade V liver injury, blood loss with the DFSD was 51% of that observed with standard gauze packing (not statistically different). Initial survival data revealed no complications attributable to the fibrin dressing. DFSD may provide simple, rapid, and definitive hemorrhage control in life-threatening liver injuries without the need for reoperation.

Topics: Animals; Female; Fibrin; Fluid Therapy; Hemorrhage; Liver; Occlusive Dressings; Random Allocation; Swine

To evaluate the acute effects of the Amplatz thrombectomy device (ATD) on peripheral venous valves in a canine model.. ATD thrombectomy was performed in 17 veins, and control experiments with use of an 8-F sheath-dilator were performed in four veins. Prethrombectomy ascending venography was performed, followed by device passage across the vein segment. Post-thrombectomy ascending venography was then performed, followed by heparinization and euthanasia. The treated veins were carefully explanted and stored in formaldehyde for histopathologic examination. Severity of valve injury was graded on a scale of 0 to 4.. In ATD-treated veins: 10 veins sustained no injury [grade 0] (diameter, 6.7 mm +/- 1.7; antegrade/retrograde approach, 5/5), five veins sustained mild injury [grade 1-2] (diameter, 5.2 mm +/- 0.8; antegrade/retrograde, 3/2), while the remaining two veins sustained moderate-to-severe injury [grade 3-4] (diameter, 5 and 6 mm; antegrade/retrograde, 1/1). In sheath-dilator treated veins: no injury [grade 0] in any of the four treated veins (mean diameter, 5.5 mm +/- 0.6; all retrograde). In ATD-treated veins, valve injury (of any grade) was significantly more frequent in veins 6 mm or less in diameter than in veins at least 7 mm in diameter (seven of 12 vs zero of five; P < .03). There was no significant association between thrombectomy approach and injury grade.. Veins 7 mm or greater in diameter were associated with no significant valve injury during ATD thrombectomy. However, long-term and short-term effects on valvular function will need to be assessed.

Topics: Animals; Anticoagulants; Axillary Vein; Catheterization; Chi-Square Distribution; Collagen; Dogs; Endothelium, Vascular; Equipment Design; Femoral Vein; Fibrin; Fixatives; Formaldehyde; Hemorrhage; Heparin; Phlebography; Saphenous Vein; Surface Properties; Thrombectomy

We observed the healing process under rigid external fixation after Salter-Harris type-1 or type-2 physeal separation at the proximal tibia in immature rabbits. Metaphyseal vessels grew across the gap with little delay; the site of separation then came to lie in the metaphysis and was bridged by endochondral ossification. Union was achieved within two days in all rabbits. Progression of endochondral ossification repaired the separated physis, thus showing 'primary healing of physeal separation'. This depends on accurate reduction and stable fixation to allow the survival of vessels across the gap.

Topics: Animals; Bone Nails; Epiphyses; Epiphyses, Slipped; External Fixators; Female; Fibrin; Follow-Up Studies; Growth Plate; Hemorrhage; Hypertrophy; Osteogenesis; Rabbits; Stainless Steel; Tibia; Wound Healing

Fibrinogen Caracas I is a dysfibrinogenemia with a mild bleeding diathesis and a defective wound healing. We have characterized this abnormal fibrinogen using transmission electron microscopy (TEM) in combination with turbidity and permeation studies. Turbidometric and permeability analysis showed that the abnormal fibrin had a significantly decreased mass:length ratio and fiber diameter. In addition, the permeability studies of plasma fibrin clots showed that the gel porosity of the abnormal fibrinogen was reduced. Images of the abnormal fibrin structure obtained using TEM showed that the fibers were thinner, much less branched and less ordered than normal fibers. Diminished fibrin fiber diameter and reduced fibrin gel porosity have been taken as hallmarks of thrombophilic dysfibrinogenemias. The results of the present study show that these features are not necessarily predictive of thrombophilia. Further studies performed on a larger number of dysfibrinogenemias need to be conducted in order to establish the implications of these parameters on the clinical outcome.

Topics: Coagulation Protein Disorders; Female; Fibrin; Fibrinogens, Abnormal; Hemorrhage; Humans; Least-Squares Analysis; Microscopy, Electron; Porosity; Wound Healing

Lung fragments from 12 patients were collected immediately after death and studied by light and electron microscopy and by immunohistochemistry to describe the main morphologic and ultrastructural aspects of the lung and platelets in leptospirosis (Weil's syndrome), to search for the possibility of disseminated intravascular coagulation (DIC), and to assess the relationship between endothelial lesions and local platelet aggregation and the leptospiral antigen distribution, as well as its relationship with the intensity of the lesions. The immunohistochemical results for fibrin aggregates were positive in the lumen and/or on the vascular endothelium in nine cases and on the alveolar surface in seven cases, leading to the diagnosis of the adult respiratory distress syndrome in these seven cases. Test results for leptospiral antigen by immunohistochemistry were positive in eight cases with no direct relationship between antigen deposits in the pulmonary vascular endothelium and intensity of the lesions. The ultrastructural findings were uniform and constant. Capillary lesions were characterized by swelling of endothelial cells, an increase in pinocytotic vesicles, and giant dense bodies in the cytoplasm of these cells. No necrosis, rupture, nor exposed subendothelial collagen was observed outside the hemorrhagic areas, and the intercellular junctions were preserved. The lung involvement in severe human leptospirosis presents as hemorrhagic pneumopathy with septal capillary lesions that are the usual cause of death. The thrombocytopenia that was verified in 11 of 12 patients in our study seems to bear no relationship to DIC and seems to be determined by activation, adhesion, and aggregation of platelets to the stimulated vascular endothelium, with an amorphous electron-dense substance between the endothelial cells and the adherent platelets in places where the subendothelial collagen was not exposed.

Topics: Adult; Antigens, Bacterial; Blood Platelets; Capillaries; Cell Adhesion; Endothelium, Vascular; Female; Fibrin; Hemorrhage; Humans; Immunohistochemistry; Leptospira interrogans; Lung; Lung Diseases; Male; Microscopy, Electron; Middle Aged; Platelet Aggregation; Thrombocytopenia; Weil Disease

Blood coagulation in vivo is initiated by factor VII (FVII) binding to its cellular receptor tissue factor (TF). FVII is the only known ligand for TF, so it was expected that FVII-deficient embryos would have a similar phenotype to TF-deficient embryos, which have defective vitello-embryonic circulation and die around 9.5 days of gestation. Surprisingly, we find that FVII-deficient (FVII-/-) embryos developed normally. FVII-/- mice succumbed perinatally because of fatal haemorrhaging from normal blood vessels. At embryonic day 9.5, maternal-fetal transfer of FVII was undetectable and survival of embryos did not depend on TF-FVII-initiated fibrin formation. Thus, the TF-/- embryonic lethal and the FVII-/- survival-phenotypes suggest a role for TF during embryogenesis beyond fibrin formation.

Topics: Animals; Blood Coagulation; Culture Techniques; Embryonic and Fetal Development; Factor VII; Female; Fetal Death; Fibrin; Gene Targeting; Hemorrhage; Hemostasis; Maternal-Fetal Exchange; Mice; Mice, Inbred C57BL; Mutagenesis; Pregnancy; Thromboplastin

Clinical experience suggests that thrombolytic-induced bleeding is associated with systemic activation of the thrombolytic system. Using fibrin specific variants of tissue-type plasminogen activator (t-PA) and making use of the apparent fibrin specificity of streptokinase (SK) in the rabbit we tested the hypothesis that minimizing systemic plasmin production and fibrinogenolysis will decrease hemorrhages in models of peripheral bleeding and embolic stroke. t-PA consumed 51% of the available fibrinogen; caused cerebral bleeds and increased peripheral bleeding time. Fibrin-specific variants of t-PA depleted less than 20% of the fibrinogen and did not cause peripheral or cerebral bleeding. However, an equipotent dose of SK converted only 12% of the available fibrinogen but increased bleeding time and caused hemorrhagic conversion in 75% of embolic stroke model animals treated. The data suggest that bleeding associated with tissue-type plasminogen activators is linked to systemic plasmin generation and subsequent fibrinogenolysis. This hypothesis does not explain the mechanism(s) of SK-induced bleeding.

Topics: Animals; Bleeding Time; Fibrin; Hemorrhage; Plasminogen; Rabbits; Streptokinase; Tissue Plasminogen Activator

The strongest fibrinolytic protease (F-III-2) in the six enzyme proteins purified from earthworm, Lumbricus rubellus [N. Nakajima et al., Biosci. Biotech. Biochem., 57, 1726-1730 (1993)] has been modified chemically with fragmented human serum albumin (mol. wt., 10,000-30,000). The modified enzyme lost the antigenicity of the native enzyme and reacted with the antisera against human serum albumin, the human serum albumin fragments, and the conjugate with the native enzyme to form precipitation lines, which fused with each other. The conjugate was significantly more resistant to inactivation by protease inhibitors in rat plasma. The enzyme was a non-hemorrhagic protein and did not induce platelet aggregation. The enzyme kept potent proteolytic activity for fibrin and fibrinogen than that of human plasmin. The enzyme easily solubilized actual fibrin clots (thrombi) of whole blood induced by thrombin in a rat's vena cava. The continuous fibrinolysis for fibrin suspension in an enzyme reactor system using the modified enzyme immobilized to oxirane-activated acrylic beads has been achieved without any inactivation of the activity at least for more than 1 month. The N-terminal amino acid sequence of the protein was also investigated and the sequence showed local similarity to those of the serine proteases such as plasmin and chymotrypsin.

Topics: Amino Acid Sequence; Animals; Cattle; Enzyme Activation; Enzymes, Immobilized; Fibrin; Fibrinolytic Agents; Hemorrhage; Humans; Male; Mice; Molecular Sequence Data; Oligochaeta; Peptide Fragments; Platelet Aggregation; Protease Inhibitors; Rabbits; Rats; Rats, Sprague-Dawley; Sequence Homology, Amino Acid; Serine Endopeptidases; Serum Albumin

Cuticle bleeding time (CBT) measurements in anesthetized rabbits were performed to assess the potential bleeding risks which may accompany the administration of tissue-type plasminogen activator (tPA) or vampire bat salivary plasminogen activator (BatPA). The dose of BatPA or tPA used in this study, 42 nmol/kg, was previously shown to be efficacious using a rabbit femoral artery thrombosis model (Gardell et al, Circulation 84:244, 1991). CBT was determined by severing the apex of the nail cuticle and monitoring the time to cessation of blood flow. CBT was minimally elevated (1.6-fold, p = NS) following bolus intravenous administration of BatPA; in contrast, bolus intravenous administration of tPA dramatically elevated CBT (6.2-fold, p < 0.05). Rabbits treated with tPA, but not BatPA, displayed profound activation of systemic plasminogen and consequent degradation of Factor VIII and fibrinogen. Elevations in CBT after the administration of tPA were reversed by the replenishment of plasma Factor VIII activity to 40% of control, but were unaffected by complete replenishment of plasma fibrinogen. The results of this study suggest that the administration of BatPA, at a dose that promotes thrombolysis, may evoke a minimal bleeding risk, relative to an equi-efficacious dose of tPA. In addition, the tPA-provoked proteolytic consumption of Factor VIII may be a key contributor to the heightened bleeding risk.

Topics: alpha-2-Antiplasmin; Animals; Bleeding Time; Chiroptera; Drug Evaluation, Preclinical; Factor VIII; Fibrin; Fibrinogen; Hemorrhage; Humans; Male; Plasminogen; Plasminogen Activators; Rabbits; Recombinant Proteins; Tissue Plasminogen Activator

This investigation compared the ability of six Latin American antivenoms (monovalent antibothropic INS, Santafé de Bogotá; polyvalent INS; polyvalent probiol, Santafé de Bogotá; antibothropic Instituto Butantan, IB, São Paulo, Brazil; polyvalent Instituto Clodomiro Picado, ICP, San José, Costa Rica; polyvalent MYN, Mexico) to neutralize various pharmacological and enzymatic effects of Bothrops atrox venom from Antioquia and Chocó, north-west of Colombia. Our results demonstrated conspicuous differences in the ability of the six antivenoms. In terms of neutralization of lethality, the highest efficacy was observed in the polyvalent INS and the lowest in the polyvalent MYN antivenom. All antivenoms were highly effective in the neutralization of hemorrhage, polyvalent INS and probiol being the highest. In the neutralization of edema-forming activity, the most effective antivenom was the polyvalent (ICP); monovalent (INS) and polyvalent (MYN) were the least effective. All antivenoms were effective in the neutralization of the myotoxic activity of B. atrox venom, the most effective being the polyvalent (INS) and antibothropic (IB). Defibrinating activity was neutralized by all antivenoms; polyvalent (MYN) showed the lowest efficiency. Polyvalent (ICP) antivenom had the highest neutralizing ability against the indirect hemolytic effect of B. atrox venom; polyvalent (MYN) did not neutralize this enzymatic activity. Overall, the polyvalent antivenom (INS) showed the highest neutralizing ability.

Topics: Animals; Antivenins; Blood Coagulation; Colombia; Crotalid Venoms; Edema; Fibrin; Hemolysis; Hemorrhage; Lethal Dose 50; Mice; Necrosis; Neutralization Tests

The activity of several proteins involved in fibrinolysis and the morphological changes in the blood vessel walls of pigs infected with highly virulent (Malawi'83) and moderately virulent (Dominican Republic '78-DR'78) ASF virus isolates were determined. Pigs infected with the Malawi'83 virus developed an increased fibrinolytic activity due to high plasma levels of tissue-plasminogen activator (t-PA) of 71.3 +/- 22.8 IU/ml (mean +/- SD), which correlated well with an increased activation of interstitial capillary endothelial cells and high levels of 1150 +/- 73.6 nM of fibrin monomer in the circulation. Animals infected with DR'78 virus, in contrast, showed an inhibition of fibrinolysis in the late stages of disease with almost a 5-fold increase of plasminogen activator inhibitor (PAI) activity of 196.0 AU/ml. These results suggest that activation of the fibrinolytic system in pigs infected with the Malawi'83 virus is probably due to increased formation and deposition of fibrin in the circulation, contributing to an increased bleeding tendency and higher mortality. On the contrary, animals infected with DR'78 virus developed an inhibition of fibrinolysis and thus a reduction in bleeding.

Topics: Acute Disease; African Swine Fever; African Swine Fever Virus; Animals; Edema; Fibrin; Fibrinolysis; Hemorrhage; Kidney; Liver; Plasminogen Inactivators; Swine; Syndrome; Thrombosis; Tissue Plasminogen Activator; Virulence

A non-hemorrhagic metalloprotease (protease L4) was purified from the venom of Chinese Mamushi (Agkistrodon halys brevicaudus) by gel filtration and anion-exchange chromatography. Protease L4 has the molecular weight of 22,000 and its optimum pH was 8.5. The protein was stable in the pH range of 5-9 and below 40 degrees C. The proteolytic activity was inhibited by metal-chelating agents and some metal ions. Calcium ion activated the activity dose-dependently, but had only a minor effect on the thermal and pH stability. L4 showed fibrinogenase activity, hydrolyzing only the A alpha chain of fibrinogen. The protease cleaved preferentially at the N-terminal of Leu and His residues of some peptides.

Topics: Agkistrodon; Amino Acid Sequence; Amino Acids; Animals; Cations; Chelating Agents; Chromatography; Enzyme Stability; Fibrin; Fibrinogen; Hemorrhage; Hydrolysis; Metalloendopeptidases; Mice; Mice, Inbred Strains; Molecular Sequence Data; Substrate Specificity; Viper Venoms

In order to study the effects of cardiopulmonary bypass (CPB) on fibrinolysis and platelet function and the possible relationship of these effects on post-operative blood loss, 127 patients undergoing CPB were examined. There was a significant reduction in the median levels of fibrinogen, plasminogen, alpha 2-antiplasmin, fibrinolytic potential and platelet aggregation during CPB (P < or = 0.001). Median levels of soluble fibrin, fibrinogen degradation products, D-dimer and PAI-1 were increased, while the level of t-PA activity remained constant. Post-CPB levels of fibrinogen and plasminogen correlated negatively with blood loss (P = 0.003 and P < 0.001, respectively) and interestingly, lower levels of alpha 2-antiplasmin and higher levels of t-PA activity before CPB were associated with greater blood loss after CPB (P < 0.001 and P = 0.004, respectively). Better pre-CPB platelet function correlated with lower levels of D-dimer before and after CPB. As expected, haemodilution had a significant effect on fibrinolytic and coagulation parameters post-CPB; the greater the haemodilution, the more the concentration of fibrinogen, plasminogen and alpha 2-antiplasmin fell post-CPB and the greater the blood loss. The increase in PAI-1 levels intra-CPB appeared to result in mean t-PA activity remaining unchanged 1 h post-CPB. Post-CPB increases in soluble fibrin were paralleled by increases in fibrinogen degradation products and D-dimer, suggesting that intra-operative contact activation is related to activation of the fibrinolytic system. The present findings indicate the greater the fibrinolytic activation, the greater the post-CPB blood loss.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; alpha-2-Antiplasmin; Blood Platelets; Cardiopulmonary Bypass; Female; Fibrin; Fibrin Fibrinogen Degradation Products; Fibrinogen; Fibrinolysis; Hemodilution; Hemorrhage; Humans; Male; Middle Aged; Plasminogen; Plasminogen Activator Inhibitor 1; Platelet Aggregation; Tissue Plasminogen Activator

Five distinct fibrin(ogen)olytic proteinases PofibC1, C2, C3, H and S were isolated by gel filtration and ion-exchange chromatographies. PofibC1, C2, C3 and H are metalloproteinases inhibited by ethylenediamine tetracetic acid (EDTA) or 1,10-phenanthroline. Only PofibH had hemorrhagic activity. PofibS is a serine proteinase, inhibited by phenylmethylsulfonyl fluoride (PMSF) or Torresea cearensis trypsin inhibitor (TCTI). All five enzymes were inhibited by dithiothreitol (DTT) or dithioerythritol (DTE). PofibC1 and C2 presented the same mol. wt of 47,000 and are acidic proteins of pI 6.2 PofibC3 is a basic proteinase of pI 8.5 and mol. wt 45,000. The hemorrhagic proteinase PofibH had a mol. wt of 58,000 and pI of 4.6 and PofibS had a mol. wt of 36,000 and pI of 4.5. The five proteinases degraded fibrin and fibrinogen. PofibC1, C2, C3 and H degraded preferentially A alpha-chains while PofibS cleaved concomitantly A alpha and B beta-chains of fibrinogen. None of these enzymes cleaved the gamma-chain of fibrinogen. When correlated with the thrombin delay time, the most active was PofibS, while PofibH and PofibC1 showed almost no activity. The proteinases also differed in the peptide cleavage of B-chain of insulin. Philodryas olfersii venom promoted in vivo a loss of the circulant plasma fibrinogen, as was observed in experiments with rats.

Topics: Amino Acid Sequence; Animals; Caseins; Colubridae; Electrophoresis, Polyacrylamide Gel; Fibrin; Fibrinogen; Hemorrhage; Humans; Insulin; Isoelectric Focusing; Male; Mice; Molecular Sequence Data; Rats; Snake Venoms; Thrombin Time

We compared the activity of a new long-half-life, fibrin-specific tissue-type plasminogen activator (TPA) variant with that of wild-type TPA in rabbit models of embolic stroke and peripheral bleeding.. In the embolic stroke model. TPA-induced clot lysis is followed by continuous monitoring of a radiolabeled clot lodged in the middle cerebral artery. Twenty-four hours after embolization and treatment with either thrombolytic agent or excipient, the brains are removed, fixed, and evaluated for cerebral hemorrhage. In a parallel template bleeding time experiment, the effects of equipotent doses of the two TPA molecules were measured.. Infusion of wild-type TPA or bolus administration of the TPA variant resulted in dose-dependent clot lysis. The TPA variant was found to be an order of magnitude more potent than wild-type TPA on a milligram-per-kilogram basis. Unlike wild-type TPA, the variant caused less systemic activation of plasminogen (P < .05) and fewer hemorrhagic transformations in this model (P < .05). The TPA variant did not extend template bleeding times.. These findings show that by combining increased fibrin specificity with decreased plasma clearance, it is possible to produce a thrombolytic agent that is more convenient and more potent than wild-tpe TPA. At the same time the significant reduction in hemorrhagic conversions may be attributable to the conservation of systemic plasminogen seen with this molecule.

Topics: alpha-2-Antiplasmin; Animals; Blood Coagulation; Cerebral Hemorrhage; Cerebrovascular Disorders; Dose-Response Relationship, Drug; Fibrin; Fibrinogen; Fibrinolysis; Half-Life; Hemorrhage; Intracranial Embolism and Thrombosis; Male; Plasminogen; Rabbits; Thrombolytic Therapy; Tissue Plasminogen Activator

The effects of plasminogen activator inhibitor-1 (PAI-1) gene inactivation on hemostasis, thrombosis and thrombolysis were studied in homozygous PAI-1-deficient (PAI-1-/-) mice, generated by homologous recombination in D3 embryonic stem cells. Diluted (10-fold) whole blood clots from PAI-1-/- and from PAI-1 wild type (PAI-1+/+) mice underwent limited but significantly different (P < 0.001) spontaneous lysis within 3 h (6 +/- 1 vs 3 +/- 1%, respectively). A 25-microliters 125I-fibrin-labeled normal murine plasma clot, injected into a jugular vein, was lysed for 47 +/- 5, 66 +/- 3, and 87 +/- 7% within 8 h in PAI-1+/+, heterozygous PAI-1-deficient (PAI-1+/-), and PAI-1-/- mice, respectively (P = 0.002 for PAI-1+/+ vs PAI-1-/- mice). Corresponding values after pretreatment with 0.5 mg/kg endotoxin in PAI-1+/+ and PAI-1-/- mice, were 35 +/- 5 and 91 +/- 3% within 4 h, respectively (P < 0.001). 11 out of 26 PAI-1+/+ but only 1 out of 25 PAI-1-/- mice developed venous thrombosis (P = 0.004) within 6 d after injection of 10 or 50 micrograms endotoxin in the footpad. Spontaneous bleeding or delayed rebleeding could not be documented in PAI-1-/- mice after partial amputation of the tail or of the caecum. Thus, disruption of the PAI-1 gene in mice appears to induce a mild hyperfibrinolytic state and a greater resistance to venous thrombosis but not to impair hemostasis.

Topics: Analysis of Variance; Animals; Cecum; Endotoxins; Erythrocyte Count; Fibrin; Fibrinolysis; Hematocrit; Hemoglobins; Hemorrhage; Hemostasis; Mice; Mice, Inbred Strains; Plasminogen Activator Inhibitor 1; Platelet Count; Pulmonary Embolism; Thrombosis

The two main maternal vessels that are a major, if not the entire, source of maternal blood for the mouse placenta are unique in possessing intraluminal valvular projections. The morphologic configuration of these projections suggests their potential to converge, diverge, and rotate blood currents flowing under systolic pressure. The intravascular occurrence of circular fibrin bodies composed of concentric fibrin strands coagulated from the plasma and almost no blood cellular elements in these strands lends credence to this concept. Histopathologic changes in the extraembryonic and embryonic tissues induced by an intraperitoneal injection of 250 or 500 mg/kg of 2-methoxyethanol, or its metabolite, 2-methoxyacetic acid, via oral gavage were determined 48 hr after dosing CD-1 mice on day 11 of pregnancy. Both compounds caused 1) marked congestion and dilatation, associated with or without fibrinous occlusions, of the main maternal vessel of the placenta, 2) serosanguinous exudation and maternal hemorrhages from the placental periphery, 3) necrosis and desquamation involving the mesometrial surface or peripheral edge of the placenta, 4) translabyrinthine embryonic hemorrhage into the maternal circulation, and 5) embryonic hemorrhages into the exocoelomic, amniotic, and pericardial cavities. These lesions signify a disordered maternal circulation in the placenta suggestive of potentially serious pathologic effects. These lesions may play a role in the resorption, reduction in fetal body weight, and syndactyly or oligodactyly attributed to 2-methoxyethanol and 2-methoxyacetic acid.

Topics: Acetates; Animals; Ethylene Glycols; Female; Fetal Diseases; Fibrin; Hemodynamics; Hemorrhage; Mice; Placenta; Pregnancy; Pregnancy Complications, Cardiovascular; Regional Blood Flow; Uterine Hemorrhage

Circulating lupus anticoagulant (LA) is associated with thrombosis in large and small vessels. To determine how often the presence of LA is associated with thrombosis within the renal microcirculation, 33 patients with systemic lupus erythematosus (SLE), renal dysfunction, and LA were identified over a 25-year period (LA group) and 32 patients with renal SLE but with normal gross coagulation screen were matched for age, sex, and biopsy timing (C group). Prevalences of serositis, neuropsychiatric illness, leukopenia, thrombocytopenia, hemolysis, anti-DS-DNA elevation, and complement reduction were similar. Arthritis was less and biologic false-positive (BFP) syphilis serology more common in LA. More LA patients had thrombotic events (LA 39% v C 13%; P = 0.014); bleeding episodes, including postbiopsy, were similar. At biopsy, hypertension (LA 55%, C 41%), serum creatinine (mean +/- SD: LA 186 +/- 168 mumol/L [2.1 +/- 1.9 mg/dL] v C 150 +/- 168 mumol/L [1.7 +/- 1.9 mg/dL]) and proteinuria (LA 2.6 +/- 3.1 g/24 h v C 3.1 +/- 2.7) were similar. Lesions by World Health Organization (WHO) class, activity, and chronicity indices, as well as immunofluorescence (IF) and electron microscopy (EM) findings, were not significantly different. Occlusive glomerular, arteriolar, and arterial fibrin thrombi, along with varying degrees of renal thrombotic microangiopathy, were seen in five of 33 patients with LA, but zero of 32 C patients (P = 0.053); three of these five patients died soon after biopsy. Overall, mortality was not different between LA and C. We conclude that the majority of patients with SLE, renal dysfunction, and LA exhibit renal morphologic findings indistinguishable from patients without LA. However, a significant minority of LA patients have thrombotic microangiopathy in their biopsy, which is accompanied by a worse prognosis.

Topics: Adolescent; Adult; Blood Coagulation; Capillaries; Female; Fibrin; Hemorrhage; Humans; Kidney; Kidney Glomerulus; Lupus Coagulation Inhibitor; Lupus Erythematosus, Systemic; Lupus Nephritis; Male; Middle Aged; Thrombosis

We describe a 50-year-old man with a severe acquired haemorrhagic syndrome. He had slightly prolonged clotting times using bovine thrombin, human thrombin and reptilase. His plasma contained a polyclonal IgG which interfered with the generation of fibrin monomers without inhibiting the aggregation of preformed monomers. The inhibitor delayed thrombin-induced fibrinopeptide A release. The IgG bound to insolubilized synthetic fibrinopeptide A (one binding site per molecule) and, with higher affinity, to fibrinogen (two binding sites per molecule). It did not bind to insolubilized fibrin monomers. The IgG did not impair the catalytic activity of thrombin toward a small synthetic substrate but inhibited the binding of thrombin to fibrinogen without binding to thrombin. The binding of the anti-fibrinopeptide A autoantibody to fibrinogen might have impaired thrombin-induced fibrinogen to fibrin conversion in vivo. This may have favoured the reported haemorrhagic syndrome which was associated with severe chronic renal insufficiency.

Topics: Autoantibodies; Binding Sites; Blood Coagulation Disorders; Fibrin; Fibrinogen; Fibrinopeptide A; Hemorrhage; Humans; Immunoglobulin G; Kidney Failure, Chronic; Male; Middle Aged; Thrombin

The purpose of this study was to determine whether a defect in hemostasis might be a factor in the etiology of exercise-induced pulmonary hemorrhage (EIPH). Hemostatic parameters were evaluated in 22 EIPH-positive and ten EIPH-negative racing horses while in a rested state. Nineteen EIPH-positive and ten EIPH-negative horses were further evaluated just before and immediately after a 15 min exercise period on a 260 m oval track. When EIPH-positive and EIPH-negative horses were compared at rest, there was no significant difference in any of the coagulation and fibrinolytic parameters studied. There was however, a significant difference in platelet function as assessed by aggregometry. The platelets from affected horses were significantly less responsive than those from nonaffected horses when exposed in vitro to the platelet agonists adenosine diphosphate, collagen and platelet activating factor. Exercise tended to increase the packed cell volume and factor VIII/von Willebrand factor and to decrease platelet aggregation responses to low concentrations of adenosine diphosphate. These effects of exercise however were quantitatively similar in both EIPH-positive and EIPH-negative horses. Reduced platelet function may therefore be a contributing factor in the bleeding characteristic of horses with EIPH.

Topics: Adenosine Diphosphate; Animals; Antithrombin III; Collagen; Factor VIII; Fibrin; Fibrin Fibrinogen Degradation Products; Fibrinogen; Hematocrit; Hemorrhage; Hemostasis; Horse Diseases; Horses; Lung Diseases; Partial Thromboplastin Time; Physical Exertion; Platelet Activating Factor; Platelet Aggregation; Platelet Count; Prothrombin Time; Thrombin Time; von Willebrand Factor

The coagulation abnormalities in 20 cases of acute promyelocytic leukemia (APL) treated at a single institution were reviewed. A remarkably uniform picture of defibrination and increased FDPs with well-preserved levels of other coagulation factors including AT-III was seen. Our data, together with those available in the literature, do not support DIC as the underlying mechanism of bleeding but seem rather to point to increased proteolysis as the cause.

Topics: Adult; Blood Coagulation Disorders; Female; Fibrin; Fibrinolysis; Hemorrhage; Humans; Leukemia, Promyelocytic, Acute; Male; Retrospective Studies

Human recombinant tissue plasminogen activator (25 micrograms) was injected into seven eyes of six patients who had developed massive fibrin deposition after vitrectomy surgery for diabetes. Six eyes had developed pupillary membranes and recurrence of tractional retinal detachment from fibrin membranes, and one eye had developed only a pupillary membrane. All pupillary membranes resolved within one hour of administration of tissue plasminogen activator, and five tractional retinal detachments resolved within 24 hours. All eyes developed evidence of intraocular bleeding after tissue plasminogen activator injection. Subsequently, six of seven eyes developed recurrence of fibrin accumulation and tractional retinal detachment.

Topics: Adult; Diabetic Retinopathy; Eye Diseases; Female; Fibrin; Hemorrhage; Humans; Male; Middle Aged; Postoperative Care; Postoperative Complications; Retinal Detachment; Tissue Plasminogen Activator; Vitrectomy

A case of infective endocarditis which was complicated with hemorrhagic fibrinous pericarditis was reported. The hemorrhagic fibrinous pericarditis is a rare complication of infective endocarditis of the aortic root and is observed massive hemorrhage into the pericardial space. These patients should be considered for the aortic valve replacement early in the course of the disease.

Topics: Aortic Valve; Aortic Valve Insufficiency; Endocarditis, Bacterial; Fibrin; Heart Valve Prosthesis; Hemorrhage; Humans; Male; Middle Aged; Pericarditis

Topics: Catheterization, Central Venous; Catheters, Indwelling; Female; Fibrin; Hemorrhage; Humans; Middle Aged

In Burma, clinicopathological studies were carried out in three young farmers who died 15, 52 and 36 h after being bitten by Russell's vipers. Clinical features included local swelling, spontaneous systemic bleeding, defibrination, shock, cardiac arrhythmia, hypoglycaemia, coma and oliguria. On admission to hospital, 15, 48 and 21 h after the bites, serum venom antigen concentrations ranged from 50 to 130 ng/ml. Autopsies revealed widespread congestion and bleeding in the lungs, gastrointestinal and renal tracts, adrenals, heart, brain and anterior pituitary. There was histopathological evidence of focal haemorrhage and fibrin deposition at the site of the bite and in the pituitary, lungs and kidneys and acute tubular necrosis. Deposition of fibrin microthrombi results from the action of venom procoagulants. Shock was attributed to increased capillary permeability, revealed clinically by conjunctival oedema. Acute pituitary/adrenal failure in one case was explained by fibrin deposition and haemorrhage in the anterior pituitary--resembling Sheehan's syndrome. Acute tubular necrosis resulted from ischaemia caused by fibrin deposition and to prerenal factors. An intractable cardiac tachyarrhythmia may have been caused by subendocardial and myocardial haemorrhages.

Topics: Adolescent; Adrenal Glands; Adult; Animals; Female; Fibrin; Hemorrhage; Humans; Kidney; Male; Microcirculation; Microscopy, Electron; Myanmar; Myocardium; Pituitary Gland; Snake Bites; Viper Venoms

Topics: Animals; Antithrombin III; Blood Coagulation; Blood Coagulation Factors; Fibrin; Hemorrhage; Heparin; Humans; Thrombosis

Fibrinolytic and fibrinase properties of the most of human organs and tissues have been studied. It has been established that fibrinolytic activity of the tissues highly varied. Fibrinolytic agents of the tissues are rather unstable to dilution, in contrast to thromboplastin, that is stable to dilutions as 1:10000 and 1:100000 and higher. All the tissues contain both activators and inhibitors of fibrinolysis. In some of them inhibitors prevail, that proves their antifibrinolytic properties. Tissue fibrinase decreasing fibrinolysis effectiveness, is detected almost in all tissues. The experiments with intravenous injection of extracts from different tissues have demonstrated that regardless of their fibrinolytic activity, the course of hemostasis impairment is of the same type: at the moment of the extract injection fibrinolysis is sharply inhibited, and then intravasal blood coagulation develops under the influence of strong tissue thromboplastin; the phase of hypercoagulemia is changed by that of hypocoagulemia attended by a secondary increase of fibrinolysis. The author believes that when "juices" of different tissues enter the blood flow the impairment of blood coagulation, by the mechanism of thrombohemorrhage syndrome (THS) takes place, and fibrinolysis is secondary-activated and represents a reaction of the second phase of THS.

Topics: Coagulants; Fibrin; Fibrinolysis; Fibrinolytic Agents; Hemorrhage; Humans; In Vitro Techniques; Thromboplastin; Thrombosis; Tissue Extracts

To evaluate potential clinical applications of nonautologous fibrin glue (FG) as a hemostatic agent in vascular surgery, we compared its efficacy to oxidized regenerated cellulose (OC) in hemostatically sealing polytetrafluoroethylene (PTFE) vascular graft anastomoses. PTFE grafts (4 mm wide and 4 to 6 cm in length) were placed to each femoral artery in a heparinized canine model, in end-to-end fashion in half of the dogs and in end-to-side fashion in the remaining dogs. Each set of graft-arterial anastomoses was then sealed with either FG or OC, determined randomly, followed by simultaneous measurement of blood loss through the graft anastomoses and needle holes. There was significantly less bleeding from anastomoses sealed with FG compared with those sealed with OC, regardless of whether the anastomoses sealed with FG compared with those sealed with OC, regardless of whether the anastomosis was constructed in end-to-end (p less than 0.03) or end-to-side (p less than 0.004) fashion; overall, the operative blood loss for grafts sealed with FG was 14 +/- 6 (mean +/- standard error of the mean) vs 99 +/- 27 ml/min for those sealed with OC (p less than 0.001). In the early postoperative period, significant groin hematomas occurred more frequently in grafts sealed with OC compared with those sealed with FG. Microscopic examination of graft-arterial specimens harvested at postoperative intervals ranging from 1 day to 3 months revealed no significant inflammatory reaction with either hemostatic agent; after 2 to 3 weeks, paired specimens appeared histologically similar despite previous treatment with either FG or OC.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Anastomosis, Surgical; Animals; Aprotinin; Biocompatible Materials; Blood Vessel Prosthesis; Cellulose; Cellulose, Oxidized; Dogs; Drug Combinations; Factor XIII; Femoral Artery; Fibrin; Fibrin Tissue Adhesive; Fibrinogen; Hemorrhage; Polytetrafluoroethylene; Postoperative Complications; Random Allocation; Thrombin; Tissue Adhesives; Vascular Patency; Wound Healing

Topics: Aprotinin; Cardiac Surgical Procedures; Drainage; Drug Combinations; Factor XIII; Female; Fibrin; Fibrin Tissue Adhesive; Fibrinogen; Hemorrhage; Humans; Male; Mediastinum; Middle Aged; Postoperative Complications; Thrombin; Tissue Adhesives

Control of bleeding from bone tissue may sometimes be difficult to maintain. Existing methods of haemorrhage control with standard bone wax can interfere with subsequent healing. This paper presents clinical and experimental results of the use of a new absorbable bone sealant, Absele a paste made from stabilised fibrin and soluble collagen.

Topics: Adolescent; Adult; Aged; Animals; Bone Diseases; Collagen; Female; Fibrin; Hemorrhage; Hemostatic Techniques; Humans; Male; Mandible; Middle Aged; Mouth; Rabbits

The sites and relative rates of peptide bond hydrolysis of the oxidized B chain of bovine insulin by two hemorrhagic proteinases, Ht-a and Ht-b, isolated from the venom of the Western Diamondback Rattlesnake, Crotalus atrox, were investigated. The results were compared with previous results on the digestion of the same substrate by the C. atrox hemorrhagic proteinases Ht-c, d, and e. Both toxins, Ht-a and Ht-b, were found to cleave the His5-Leu6, His10-Leu11, Ala14-Leu15, and Tyr16-Leu17 bonds of the oxidized insulin B chain. In addition, Ht-a cleaves the Asn3-Gln4 bond, whereas Ht-b cleaves the Gly23-Phe24 bond. The cleavage specificity of Ht-b on the insulin B chain is identical to that of the weakly hemorrhagic isoenzymes Ht-c and Ht-d. Hemorrhagic proteinase Ht-a cleaves the Ala14-Leu15 bond most rapidly, having a turnover number of 12.6 min-1 which was approximately twice as fast as the Tyr16-Leu17 bond turnover of cleavage. Hemorrhagic proteinase Ht-b, on the other hand, cleaves the Tyr16-Leu17 bond fastest, having a turnover number of 61.3 min-1. The Ala14-Leu15 bond is the peptide bond cleaved the second fastest by Ht-b, with a turnover number of 48.2 min-1. The five hemorrhagic toxins from Crotalus atrox venom were also examined for their capability to hydrolyse basement membrane preparations, and the identities of the digested proteins comprising the basement membrane were determined. From the results it is concluded that all five hemorrhagic toxins cleave laminin and the component of the basement membrane referred to as band a.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Amino Acid Sequence; Animals; Basement Membrane; Crotalid Venoms; Fibrin; Fibronectins; Hemorrhage; Hydrolysis; Insulin; Laminin; Molecular Sequence Data; Peptide Hydrolases

We evaluated 40 consecutive carotid endarterectomy specimens for the presence of fibrin. Intraplaque hemorrhage was noted in 93% of specimens. At the plaque surface, there were two patterns of fibrin distribution. Type I, suggesting a lumen thrombus, was found in 7 specimens. Type II, suggesting an intraplaque hemorrhage at the lumen surface, was found in 15 specimens. These changes were not significantly associated with the presence of ischemic symptoms or the use of antiplatelet or anticoagulant medications. All specimens with Type I change had arteriographic evidence of at least 70% diameter stenosis. The frequent lack of fibrin at the plaque surface suggests that there may be inherent limitations of standard medical treatment for carotid artery disease.

Topics: Arteriosclerosis; Carotid Arteries; Carotid Artery Diseases; Carotid Artery Thrombosis; Endarterectomy; Female; Fibrin; Hemorrhage; Histocytochemistry; Humans; Immunoenzyme Techniques; Male; Middle Aged; Prospective Studies

Formation of a hemostatic plug represents one of the earliest responses to vessel wall injury. Platelets react to any discontinuity in the vascular endothelium through initial contact, spreading, and formation of a thrombus (or aggregate). This development of a primary hemostatic plug requires platelet membrane receptors through which the adhesive macromolecules, von Willebrand factor (vWF) and fibrinogen, anchor platelets to the vessel wall and link them to each other. There are two receptor pathways--classic and alternative--for the binding of vWF to platelets; the latter induced by thrombin, and adenosine diphosphate (ADP) is shared with fibrinogen. Synthetic peptides, patterned after known binding domains of adhesive molecules, have been designed to inhibit their interactions with platelet receptors. A secondary hemostatic plug, composed of platelets enmeshed in fibrin, results from the action of thrombin, which is not only essential for formation of fibrin but also for exposure of platelet receptors for adhesive molecules and for "activation" of factors V and VIII. Thrombin generation is greatly enhanced through the activity of the prothrombinase complex formed on the surface of platelets, perturbed endothelial cells, and leukocytes. A pivotal event is activation of factor X through the intrinsic and extrinsic coagulation pathways. Binding of factors IXa and VIIa to the vascular endothelium represents a localized mechanism for factor Xa generation. Formation of a platelet and fibrin thrombus is controlled by regulatory mechanism: prostacyclin, endogenous heparin-antithrombin III complex, thrombomodulin-protein C-protein S system, and the fibrinolytic system. The balance of all components--vessel wall, platelets, adhesive and coagulation proteins, regulatory mechanisms--determines the effectiveness of the hemostatic plug in maintaining the structural and functional integrity of the circulatory system. An approach to detection of hemostatic derangements in patients at risk evolves from a full understanding of inherited and acquired deficiencies affecting each step of hemostatic plug formation and from selective use of laboratory tests.

Topics: Blood Coagulation Tests; Blood Platelets; Endothelium; Fibrin; Fibrinolysis; Hemorrhage; Hemostasis; Platelet Adhesiveness; Platelet Aggregation; Risk; Thrombosis

This study reviews liver disease in toxemia of pregnancy based on 102 cases submitted to the Armed Forces Institute of Pathology. The common clinical features were right upper quadrant and epigastric pain, nausea, vomiting, and elevation of the serum transaminases. Jaundice occasionally developed. These occurred in severe preeclampsia or eclampsia and their cause was usually recognized. However, hepatic symptoms and signs did result in inappropriate diagnoses and misdirected therapy. Such confusion occurred when these were the initial problems confronting the clinician in women presenting with advanced toxemia due to poor prenatal care. They were also likely to be misleading when other more classic parameters, such as blood pressure and proteinuria, were only midly abnormal. Central nervous system complications were the common cause of death but liver disease could be partially or wholly responsible. Extensive periportal lesions, hepatic hematomas, spontaneous rupture, and infarction all contributed to hepatic injury and to morbidity. Fibrin deposition, hemorrhage, or both in the periportal areas was characteristic of the histopathology. Scanning electron microscopy validated this spectrum of change. A toxemic vasculopathy related to severe vasospasm in the hepatic arterial circulation may be responsible.

Topics: Eclampsia; Female; Fibrin; Hemorrhage; Humans; Infarction; Liver; Liver Diseases; Necrosis; Pre-Eclampsia; Pregnancy

This investigation was undertaken to determine the relationship, if any, between peripheral placental separation and idiopathic premature labor. Ninety placentas from prematurely delivered patients (who had had no antepartum bleeding) were examined grossly and microscopically. Criteria for antepartum peripheral placental separation included adherent clot, with fibrin deposition and lamination, as well as polymorphonuclear infiltration and marginal decidual necrosis. Forty-nine placentas showed unequivocal evidence of previous peripheral separation. Another three placentas showed presumptive evidence of previous peripheral separation. It is suggested that this separation is of venous origin, and that it may play a role in the process of premature labor. This is not necessarily a cause and effect relationship.

Topics: Abruptio Placentae; Decidua; Female; Fibrin; Hemorrhage; Humans; Obstetric Labor, Premature; Placenta; Placenta Diseases; Pregnancy

Fibrin glue Beriplast was used during cardiovascular surgery in 97 patients. The fibrin seal was used for hemostasis on anastomoses, patches and suture lines. Moreover, the glue was applied for epicardial fixation of aorto-coronary vein grafts to prevent postoperative graft kinking. Following extrapleural ligation of patent duct in premature infants, the parietal pleura was fastened to the thoracic wall to prevent extrapleural pneumothorax or hemorrhage. After accidental dissection of the thoracic duct in infants, leakage of chyle could be sealed successfully in 6 cases. Hemorrhage from the sealed surfaces of suture lines was not observed. Viral hepatitis occurred postoperatively in 2 patients (3% of the operations for acquired heart disease), both of whom had also received clotting factor concentrate and blood transfusion because of postoperative hemorrhage not related to fibrin sealed surfaces. A causal relation between the hepatitis and application of the pasteurized fibrin glue seems very unlikely. Although fibrin glue certainly cannot replace the surgical suture, it appears to be a valuable aid under special conditions.

Topics: Adult; Ductus Arteriosus, Patent; Female; Fibrin; Fistula; Hemorrhage; Humans; Intraoperative Complications; Male; Middle Aged; Thrombin; Tissue Adhesives

Topics: Antifibrinolytic Agents; Emergencies; Fibrin; Fibrinolysin; Fibrinolysis; Hemorrhage; Humans; Protease Inhibitors

Fibrin sealant (FS) is a biologic adhesive containing highly concentrated human fibrinogen that is effective in the face-to-face sealing of tissues, and in establishing hemostasis. We evaluated FS in 32 experimentally produced splenic injuries in six adult mongrel dogs. Complete hemostasis was achieved in all animals prior to closure. The dogs were reexplored postoperatively at intervals varying from four hours to six weeks (mean +/- SD, 21 +/- 20 days). When the dogs were killed, there was no gross evidence of splenic disruption or recurrent bleeding; all of the spleens had developed well-healed capsules. Histologic examination demonstrated a regenerated fibrous capsule extending over the superficial injuries as well as into the deep injuries, without significant inflammatory response. We conclude the following: that FS provides adequate hemostatic control of superficial and deep splenic injuries, FS has good systemic and local compatibility, it can be applied to bleeding parenchymal wounds, it reduces the need for parenchymal sutures that may be traumatic, and it promotes splenic wound healing.

Topics: Animals; Dogs; Fibrin; Hemorrhage; Hemostasis; Splenic Diseases; Tissue Adhesives

Topics: Animals; Eye; Eye Diseases; Fibrin; Hemorrhage; Rabbits; Time Factors

In the last year fibrin glue Tissucol was used for local hemostasis in 21 patients subjected to correction of tetralogy of Fallot (ToF) and in 10 patients subjected to Senning-procedure in transposition of the great arteries (TGA). The postoperative blood loss was compared with the blood loss of 20 ToF-patients and 10 TGA-patients who had undergone correction one year ago without fibrin glue. Between the 2 groups were no differences in age, sex, bodyweight (BW), coagulation state or operative management. Two hours postoperatively the blood loss with fibrin glue was 2.2 ml/hr/kg BW in ToF-patients and 2.4 ml/hr/kg BW in TGA-patients, whereas without fibrin glue it was 4.2 ml/hr/kg BW in ToF (p less than 0.01) and 4.5 ml/hr/kg BW in TGA (p less than 0.01). The same significant difference (p less than 0.01) was found 6 hours postoperatively with 1.4 versus 2.2 ml/hr/kg BW in ToF and 1.9 versus 2.5 ml/hr/kg BW in TGA. Over the following 18 hours the secretion from the chest tubes was identical in both groups. Six patients with ToF and one patient with TGA required reoperation for bleeding. The blood loss per kg BW per hour at reoperation was 6.9 ml with and 8.2 ml without fibrin glue (N.S.). The blood loss of patients who did not require reoperation at the same time was 4.6 times lower with fibrin glue and only 3.7 times lower without fibrin glue. Fibrin glue reduces blood loss after intracardiac repair of ToF and TGA by local hemostasis at patches and suture lines. The application of fibrin glue can facilitate differentiation of surgical bleedings and the indication for reoperations.

Topics: Child; Child, Preschool; Female; Fibrin; Hemorrhage; Hemostasis; Humans; Infant; Infant, Newborn; Male; Reoperation; Tetralogy of Fallot; Tissue Adhesives; Transposition of Great Vessels

Topics: Disseminated Intravascular Coagulation; Electrophoresis, Polyacrylamide Gel; Fibrin; Fibrin Fibrinogen Degradation Products; Fibrinopeptide A; Fibrinopeptide B; Hemorrhage; Humans; Models, Chemical; Molecular Weight; Thrombosis

The effects of minimal intermittent heparinization and of conventional heparinization on endogen fibrinogen concentration as well as on fibrin deposits were studied on 17 on patients hemodialysis. It was shown that the minimal intermittent heparinization did non reduce dialysis efficiency and that a total heparin dosage of 6,000 units is the lowest safe limit.

Topics: Adult; Female; Fibrin; Fibrinogen; Hemorrhage; Heparin; Humans; Male; Microscopy, Electron, Scanning; Middle Aged; Renal Dialysis

Ten of 11 patients undergoing peritoneovenous (LeVeen) shunt placement for intractable ascites had disseminated intravascular coagulation (DIC) following the shunt procedure. Intraoperative ascitic fluid specimens revealed fibrin split products (FSP) in high titer (1:100-1:1600) in all patients. Endotoxin was found in 6 of 11 ascitic fluid samples but in no plasma samples. Activated clotting factors, clot inhibitors, excess protein, and fibrinolytic activity were not found in ascitic fluid. Clotting factor levels were much lower than in plasma. Bleeding occurred after operation in two patients; this appeared to be related to the severity of liver dysfunction as demonstrated by elevations of bilirubin, serum glutamic oxalocetic transaminase (SGOT), serum glutamic pyruvic transaminase (SGPT), and preoperative DIC. It is concluded that the LeVeen shunt coagulopathy is DIC, and may be related to exposure of the systemic circulation to FSP-rich ascitic fluid that may activate the coagulation mechanism. Bleeding complications do not appear to be related to the severity of the post shunt coagulopathy, but rather to the severity of liver dysfunction and presence of preoperative DIC (probably caused by the liver disease).

Topics: Adult; Aged; Ascites; Ascitic Fluid; Blood Coagulation Tests; Disseminated Intravascular Coagulation; Fibrin; Hemorrhage; Humans; Liver Function Tests; Male; Middle Aged; Peritoneovenous Shunt; Vascular Surgical Procedures

Topics: Blood Vessel Prosthesis; Bone Transplantation; Bronchial Fistula; Fibrin; Hemorrhage; Splenic Rupture; Surgery, Plastic; Tissue Adhesives

Bleeding is a common complication in patients suffering from multiple myeloma. In some cases a defect in fibrin formation has been suggested as one possible cause of haemorrhagic tendency. As shown in this investigation the defect in fibrin formation, ascertained using PAGE, is due to a lack of alpha-chain polymerization of fibrin monomers in 5/11 patients with IgG myeloma and in 2/5 patients with IgM paraproteinaemia. No disturbed fibrin polymerization could be observed in IgA myeloma (n = 6). Factor XIII concentrations of subunit A and to a lesser extent of subunit S (Laurell technique) were highly elevated in all cases with regular fibrin formation. comparable values were obtained by measuring the transamidase activity of factor XIII by incorporation of 14C-labelled purtrescin into casein. Levels up to 600% of normal could be recorded. In contrast, all patients with a lack of alpha-chain polymerization had a factor XIII activity within the normal range. Addition of factor XIII concentrate to plasma from patients with defective fibrin formation led in 5/8 cases to a partial cross-linking of alpha-monomers. we conclude that in some cases paraproteins can inhibit the factor XIII and prevent its action on fibrin.

Topics: Blood Coagulation Tests; Electrophoresis, Polyacrylamide Gel; Factor XIII; Fibrin; Hemorrhage; Humans; Immunodiffusion; Immunoglobulins; Multiple Myeloma; Paraproteinemias

The intratracheal injection into rabbits of low molecular weight C5-derived chemotactic fragments (C5fr), prepared from zymosan-activated serum, induced an acute pulmonary inflammation characterized by intraalveolar accumulation of neutrophils, erythrocytes, and edema fluid. In separate experiments, depletion of circulating pulmonary neutrophils and absorption of C5fr with immobilized antibody to homogenous human C5a prevented the observed inflammatory changes, indicating a requirement for these two elements in initiating this reaction. When examined by transmission and scanning electron microscopy, lungs of C5fr-injected rabbits revealed pulmonary neutrophils, often appearing partially degranulated, in alveolar, pulmonary capillary, and interstitial spaces. Alveolar spaces and, less often, the interstitial compartment contained fibrinoid deposits with leukocytes and erythrocytes enmeshed in the fibrin strands. Injury to the pulmonary vascular endothelium consisted of bleb formation in capillaries and endothelial basement membrane separation with subendothelial accumulation of inflammatory cells in venules. Type I, but not type II, epithelial cell damage included blebbing and epithelial cell basement membrane detachment. Endothelial and epithelial layer damage was always associated with pulmonary neutrophils continguous to the injured structures. These studies indicate the potential for alveolar epithelial and capillary injury in neutrophil-associated pulmonary inflammation resulting from intraalveolar accumulation of chemotactic substances.

Topics: Animals; Chemotaxis, Leukocyte; Complement C5; Edema; Female; Fibrin; Hemorrhage; Inflammation; Lung; Lung Diseases; Male; Microscopy, Electron, Scanning; Neutrophils; Rabbits

Topics: Blood Coagulation; Blood Coagulation Disorders; Blood Transfusion; Calcium; Disseminated Intravascular Coagulation; Factor XIII; Factor XIII Deficiency; Female; Fibrin; Fibrinogen; Half-Life; Hemorrhage; Humans; Leukemia; Liver Diseases; Male; Plasma; Pregnancy; Thrombin; Time Factors

Old calcified fibrin coagula are frequently found in simple bone cysts. They provide a scaffold on which new bone is laid down, in a process analogous to endochondral ossification. It is suggested that these coagula are derived in substantial part from the plasma-like contents of the cyst, after the release of plasma-clotting factors as the result of injury. Major haemorrhage is not involved and in many cases there is no antecedent fracture. The phenomenon is not seen in other common cystic conditions of bone and its recognition is thus helpful in the histological diagnosis of simple bone cyst. Cystic bone infarcts and their possible confusion with simple bone cysts are also briefly discussed.

Topics: Blood Coagulation; Bone Cysts; Fibrin; Fractures, Bone; Hemorrhage; Humans; Osteogenesis; Radiography

184 autopsy cases with liver diseases were examined clinicopathologically with special reference to the incidence and distribution of microthrombi and classic thrombi in various organs. Microthrombi and/or classic thrombi were found in one or more organs in 50.0% to 59.4% of the patients with various liver diseases. But only 4 among 184 patients had many microthrombi in more than three organs and the incidence of disseminated intravascular coagulation seemed to be low in autopsy cases with liver diseases. Incidence of microthrombi showed no significant difference in the groups with and without portal vein thrombosis. Hemorrhage in the upper alimentary tracts of the patients with liver cirrhosis did not seem to develop by disseminated intravascular coagulation. Consumption of clotting factors in liver diseases seemed to occur by thrombus formation in portal vein and esophageal varices and by hemorrhage in various organs.

Topics: Autopsy; Blood Platelets; Disseminated Intravascular Coagulation; Fibrin; Fibrinolysis; Hemorrhage; Humans; Kidney; Liver Diseases; Lung; Spleen

We undertook an ultrastructural study of the dual processes of hemolysis and vitreous membrane formation during the resolution of vitreous blood clots in rabbits. Red blood cell degradation began within 24 hours before the onset of the inflammatory response and occurred mainly in the extracellular matrix. Macrophage activity was directed at clearing lysed RBC debris, rather than engulfing whole RBCs. Hemolysis in the vitreous may have been initiated by the unfavorable microenvironment. Two types of vitreous membranes occurred during vitreous clot lysis. Cellular membranes were composed of aggregates of giant macrophages enclosed within a thin collagen sheet. Acellular membranes developed from coaggregated vitreous collagen fibers. A prominent acellular membrane surrounded the blood clot as a pseudocapsule. No fibroblasts or fresh collagen deposition were observed.

Topics: Animals; Blood Coagulation; Erythrocytes; Fibrin; Hemolysis; Hemorrhage; Membranes; Rabbits; Time Factors; Vitreous Body

Topics: Amino Acid Oxidoreductases; Animals; Blood Coagulation; Electrophoresis, Disc; Fibrin; Hemorrhage; Hot Temperature; Humans; Hydrogen-Ion Concentration; In Vitro Techniques; Isoelectric Point; Molecular Weight; Phospholipases; Phosphoric Diester Hydrolases; Prothrombin; Rabbits; Rats; Snake Venoms

Topics: Animals; Cell Membrane; Cell Nucleus; Ciliary Body; Cytoplasm; Eye Diseases; Fibrin; Hemorrhage; Microscopy, Electron; Pigment Epithelium of Eye; Rabbits; Thrombocytopenia

Using selectively immunological methods, it was possible, through FSP determination, for plasmin activities and plasminogen concentrations to be occasionally and exclusively detected in inflammatorily altered liquores and in bloody liquores, respectively. Thus, bloody cerebrospinal fluid, in contrast with inflammatorily altered liquor, usually shows free fibrinolytic activity, so that antifibrinolytic therapy of intracranial aneurysmal hemorrhage is pathophysiologically justifiable.

Topics: Central Nervous System Diseases; Cerebrospinal Fluid Proteins; Chronic Disease; Fibrin; Fibrin Fibrinogen Degradation Products; Fibrinogen; Fibrinolysin; Hemorrhage; Humans; Inflammation; Plasminogen

Fibrin clots may form in the biliary tract from hemobilia or in inflammatory disease. There is a wide variation in the clinical course of such clots which is exemplified by 9 patients. They may either dissolve through fibrinolysis, get ejected into the intestine, remain and obstruct the biliary tract, or may even transform into gallstones. In order to elucidate the mechanisms involved, the behavior of blood clots in bile was studied in vitro. A model was constructed of the biliary tract and, drained by a T-tube, where human bile circulated with a flow rate resembling that in vivo. When a small amount of human blood was injected, it flowed immiscibly to the lowest level, displaced the bile, and formed a clot of pure blood. Even a minor bleeding may thus form a coagulum. This is different from the mixed clot of blood and bile that forms in experiments simulating major hemorrhage. These findings are related to clinical experience and especially to the disappearance of "retained stones" with or without the use of dissolving agents.

Topics: Biliary Tract; Biliary Tract Diseases; Blood Coagulation; Cholangiography; Cholecystectomy; Cholelithiasis; Cholestasis; Diagnostic Errors; Female; Fibrin; Fibrinolysis; Gallstones; Gastrointestinal Hemorrhage; Hemorrhage; Humans; Male; Models, Biological; Postoperative Complications

Complete inhibition of vitreous fibrinolytic activity with 4-amino-methylcyclohexane carbonic acid was associated with significantly delayed resolution of vitreous hemorrhages in rabbits. However, polyacrylamide gel electrophoresis indicated but a slight delay in the removal of the fibrin component of vitreous clots, and most of the residual vitreous opacity comprised intact red blood cells. Fibrin degradation products may act as chemotactic agents, promoting the removal of red blood cells by leukocytes; hence, their absence in treated rabbits might explain in part the delayed red blood cell clearance.

Topics: Absorption; Animals; Chemotaxis, Leukocyte; Cyclohexanecarboxylic Acids; Erythrocytes; Eye Diseases; Fibrin; Fibrin Fibrinogen Degradation Products; Fibrinolysis; Hemorrhage; Phagocytosis; Rabbits; Tranexamic Acid; Vitreous Body

When injury of a major vessel can be ruled out as the cause of bleeding after tonsillectomy, a discrete disturbance of hemostasis must be considered. These are mainly slight thrombopathies or a pathologically increased fibrinolysis, which were not detected by routine tests and the past history. In former times severe bleeding disorders were a strict contra-indication for tonsillectomy. Under the supposition of an exact coagulogram and the substitution of highly purified factor concentrates the risk of severe post-tonsillectomy hemorrhages in such patients today is nearly the same as in patients with a normal hemostase.

Topics: Antifibrinolytic Agents; Blood Coagulation Factors; Blood Platelet Disorders; Fibrin; Hemorrhage; Hemorrhagic Disorders; Humans; Postoperative Complications; Tissue Adhesives; Tonsillectomy

Topics: Animals; Eye Diseases; Fibrin; Fibrin Fibrinogen Degradation Products; Fibrinolysis; Hemolysis; Hemorrhage; Plasminogen Activators; Rabbits; Vitreous Body

We wished to know if excision of artificially produced intravitreal vessels would cause bleeding and if the hemorrhage could be controlled by increasing the intraocular pressure. In 17 rabbit eyes, the distal end of several intravitreal blood vessels was excised and removed by the Peyman vitrophage. No significant bleeding occurred from the vessels in 13 eyes, and in the remaining four bleeding stopped after 30 seconds or less of increased intraocular pressure. In one month of observation after surgery, there was no evidence of delayed hemorrhage. Electron microscopy of several transected intravitreal vessels revealed that vessel constriction, platelets and fibrin strands contributed to the prevention of immediate and delayed hemorrhage.

Topics: Ammonium Chloride; Animals; Disease Models, Animal; Endothelium; Erythrocytes; Eye Diseases; Fibrin; Hemorrhage; Hemostasis; Intraocular Pressure; Microscopy, Electron; Postoperative Complications; Rabbits; Retinal Diseases; Retinal Vessels; Time Factors; Vitreous Body

In a prospective study of 13 patients undergoing open-heart surgery with extracorporeal circulation, marked qualitative platelet function defects were observed in addition to the usually occurring drop of the thrombocyte count. At the end of bypass, the following test results were significantly abnormal: concentration of fibrinogen and of circulating fibrin degradation products, platelet count, platelet adhesiveness to glass beads, and platelet aggregation induced by low and high doses of ADP. One to 2 hours after neutralization of heparin with protamine sulfate all abnormal test results improved, but the template bleeding time was markedly prolonged in 10 patients. There was no correlation between length of bypass and platelet fall and between concentration of circulating fibrin degradation products and extent of platelet dysfunction. An apparent correlation was found between the length of the postoperative bleeding time and the number of units of blood transfued during surgery. The results of this study suggest that dilution of the patient's own platelets by nonviable platelets contained in 3-day-old transfused ACD blood and the production of a refractory state of the patient's circulating platelets to ADP induced aggregation played a significant role in the development of platelet function abnormalities during extracorporeal circulation.

Topics: Adenosine Diphosphate; Blood Cell Count; Blood Platelet Disorders; Blood Platelets; Blood Proteins; Cardiac Surgical Procedures; Collagen; Epinephrine; Extracorporeal Circulation; Fibrin; Fibrinogen; Hemorrhage; Humans; Platelet Adhesiveness; Platelet Aggregation; Platelet Factor 3; Postoperative Complications; Prospective Studies; Protamines; Time Factors

The effects of various combinations of streptokinase-induced hyperfibrinolysis, electric shock, myocardial ischemia, and ventricular fibrillation on cat pericardial and epcardial fibrinolytic activity were studied. Streptokinase alone or electric shock alone slightly increased the periepicardial fibrinolytic activity but epicardial rebleeding did not occur. However, streptokinase infusions followed by electric shock and/or myocardial ischemia and/or ventricular fibrillation significantly incrased the periepicardial fibrinolytic activity and rebleeding of the epicardium occurred. Topical application of the fibrinolytic inhibitor epsilonaminocaproic acid (EACA) prevented the epicardial rebleeding.

Topics: Aminocaproates; Animals; Blood Coagulation; Blood Coagulation Tests; Cardiac Surgical Procedures; Cardiopulmonary Bypass; Cats; Electric Stimulation; Fibrin; Fibrinogen; Fibrinolysis; Heart Diseases; Hemorrhage; Injections, Intravenous; Ischemia; Pericardium; Postoperative Complications; Streptokinase; Ventricular Fibrillation

Topics: Blood Coagulation Factors; Disseminated Intravascular Coagulation; Fever; Fibrin; Fibrinolysis; Hemorrhage; Heparin; Humans; Liver; Sunstroke; Temperature; Thrombocytopenia

Topics: Fibrin; Fibrinogen; Hemorrhage; Humans; Liver Cirrhosis; Liver Diseases

Fibrosing uremic pleuritis is a newly recognized late complication of uremia. Extreme incarceration of the lining and chest wall can occur with disabling restriction of pulmonary function. Decortication of the chest wall and the lung can be carried out safely with minimal bleeding and restoration of pulmonary function.

Topics: Adult; Female; Fibrin; Hemorrhage; Humans; Lung; Lung Diseases; Pleurisy; Radiography; Time Factors; Uremia; Wound Healing

Topics: Acute Disease; Antithrombins; Blood Cell Count; Blood Coagulation Tests; Disseminated Intravascular Coagulation; Fibrin; Fibrinogen; Fibrinolysis; Hemorrhage; Humans; Leukemia; Leukemia, Monocytic, Acute; Leukemia, Myeloid; Leukemia, Myeloid, Acute; Liver Cirrhosis; Lymphatic Diseases; Platelet Adhesiveness; Prothrombin Time; Retinal Detachment; Thrombin; Thrombophlebitis

Topics: Blood Coagulation Tests; Craniocerebral Trauma; Disseminated Intravascular Coagulation; Fibrin; Fibrinogen; Hemorrhage; Humans; Thrombocytopenia

Multiple components of the fibrinolytic mechanism (plasminogen, plasmin, antiplasmin, fibrinogen, fibrin degradation products) and factor II (prothrombin) levels were studied in 40 children with cyanotic congenital heart disease (CCHD) prior to corrective surgery. Seven of these were also studied post-operatively. A further 17 children were studied after corrective surgery only. Pre-operatively, increased fibrinolysis could bedemonstrated in only 7.5-12% of patients, and there was no correlation between the levels of fibrinolytic components and the severity of polycythemia or post-operative blood loss. There was no evidence of fibrinolysis post-operatively. Pre-operatively, low prothrombin levels were common (25%), were correlated with the amount of post-operative bloodloss and were restored to normal by corrective surgery. Hypoprothrombinaemia is one of the most significant haematological abnormalities in CCHD.

Topics: Child; Fibrin; Fibrinogen; Fibrinolysin; Fibrinolysis; Heart Defects, Congenital; Hemorrhage; Humans; Hypoprothrombinemias; Plasminogen; Prothrombin

Topics: Administration, Oral; Animals; Constriction; Dyspnea; Female; Fibrin; Growth; Heart Ventricles; Hemorrhage; Hypertrophy; Inclusion Bodies; Injections, Intraperitoneal; Iron; Liver; Lung; Lymphocytes; Mast Cells; Muscle, Smooth; Organ Size; Pulmonary Artery; Pulmonary Edema; Pulmonary Veins; Pyrrolizidine Alkaloids; Rats; Time Factors

Rats were inoculated with viable Salmonella dublin organisms, or a crude S dublin endotoxin, at the fourteenth and nineteenth days of pregnancy. They were killed at intervals up to 96 hours after inoculation, and the pathogenesis of the lesions was compared. At each stage of pregnancy the initial lesions produced by live bacteria and crude endotoxin showed important similarities, confirming the significance of endotoxin in the pathogenesis of placental damage. There were differences in the later stages of the pathogenic process. Comparisons of the process of placental damage at the two stages of pregnancy have suggested that the same mechanism acts throughout the last third of pregnancy and that thrombosis and disseminated intravascular coagulation are not an important part of the mechanism of placental damage.

Topics: Animals; Disseminated Intravascular Coagulation; Endotoxins; Female; Fetal Death; Fibrin; Granulation Tissue; Hemorrhage; Necrosis; Neutrophils; Placenta; Placenta Diseases; Pregnancy; Pregnancy Complications, Infectious; Rats; Salmonella Infections, Animal; Sodium Chloride; Thrombosis; Time Factors; Toxemia; Uterus

Topics: Animals; Arteries; Blood Coagulation Tests; Dermatologic Surgical Procedures; Digestive System Surgical Procedures; Fibrin; Fibrinolysis; Hemorrhage; Humans; Kidney; Liver; Muscles; Postoperative Complications; Rabbits; Streptokinase; Time Factors; Veins

Topics: Adult; Arm; Biopsy; Blood Coagulation; Blood Platelets; Blood Transfusion; Blood Vessels; Collagen; Endothelium; Erythrocytes; Female; Fibrin; Granulation Tissue; Hemorrhage; Humans; Male; Microscopy, Electron; Middle Aged; Platelet Adhesiveness; Platelet Aggregation; Time Factors; von Willebrand Diseases; Wounds and Injuries

Topics: Adult; Basement Membrane; Biopsy; Collagen; Cytoplasm; Diagnosis, Differential; Epithelial Cells; Erythrocytes; Fibrin; Fluorescent Antibody Technique; Glycogen; Hemorrhage; Hemosiderin; Hemosiderosis; Humans; Leukocytes; Lung; Lung Diseases; Macrophages; Male; Microscopy, Electron; Pulmonary Alveoli; Pulmonary Edema

Topics: Adrenal Gland Diseases; Animals; Botulinum Toxins; Botulism; Capillary Permeability; Dysentery, Bacillary; Fibrin; Hemorrhage; Male; Monocytes; Platelet Adhesiveness; Rats; Salmonella Infections; Salmonella typhimurium; Shigella dysenteriae

Topics: Afibrinogenemia; Animals; Basement Membrane; Blood Coagulation; Blood Coagulation Tests; Blood Platelets; Capillaries; Capillary Fragility; Capillary Permeability; Clot Retraction; Ecchymosis; Fibrin; Fibrinogen; Hemorrhage; Humans; Methods; Platelet Adhesiveness; Thrombocytopenia; Wound Healing

Topics: Aged; Autopsy; Blood Coagulation; Cadaver; Erythrocytes; Fibrin; Hemorrhage; Humans; Male; Microscopy, Electron, Scanning; Middle Aged; Postmortem Changes; Skin; Streptokinase; Thrombosis; Time Factors

Topics: Blood Coagulation; Carotid Arteries; Disseminated Intravascular Coagulation; Female; Fibrin; Forensic Medicine; Hemorrhage; Humans; Microscopy, Electron, Scanning; Postmortem Changes; Punctures; Thrombosis

Topics: Adenosine Diphosphate; Adult; Aged; Antithrombins; Blood Cell Count; Blood Coagulation; Blood Coagulation Factors; Blood Coagulation Tests; Blood Platelets; Clot Retraction; Collagen; Disseminated Intravascular Coagulation; Epinephrine; Female; Fibrin; Fibrinogen; Fibrinolysis; Hemorrhage; Humans; Male; Middle Aged; Plasminogen; Platelet Adhesiveness; Polycythemia Vera; Prothrombin Time; Thrombin; Thrombophlebitis

Topics: Animals; Biopsy; Bronchi; Cilia; Dogs; Epithelial Cells; Exudates and Transudates; Fibrin; Graft Rejection; Hemorrhage; Lung; Lung Transplantation; Methods; Microscopy, Electron; Microscopy, Electron, Scanning; Necrosis; Pulmonary Alveoli; Pulmonary Edema; Replantation; Time Factors; Transplantation, Homologous

Topics: Afibrinogenemia; Blood Coagulation Tests; Diagnosis, Differential; Fibrin; Fibrinogen; Fibrinolysis; Hemorrhage; Hemorrhagic Disorders; Humans; Methods; Prothrombin Time; Time Factors

Topics: Animals; Blood Cell Count; Blood Coagulation; Blood Coagulation Tests; Blood Platelets; Endothelium; Female; Fibrin; Fibrinogen; Hemorrhage; Injections, Intradermal; Microscopy, Electron; Necrosis; Prothrombin Time; Rabbits; Spider Bites; Spiders; Thrombosis; Time Factors; Venoms

Topics: Administration, Oral; Biopsy; Blood Coagulation; Buttocks; Child, Preschool; Cyclohexanecarboxylic Acids; Fibrin; Fibrinogen; Fibrinolysis; Hemorrhage; Humans; Infant; Infant, Newborn; Injections, Intravenous; Lymphangioma; Male; Postoperative Complications; Surgical Wound Infection

Topics: Abdominal Injuries; Animals; Blood Coagulation; Blood Platelets; Blood Vessels; Erythrocytes; Fibrin; Hemorrhage; Hemostasis; Microscopy, Electron, Scanning; Platelet Adhesiveness; Prothrombin Time; Rats; Skin

Topics: Animals; Blood Coagulation; Blood Coagulation Factors; Blood Platelets; Cell Aggregation; Dogs; Fibrin; Fibrinogen; Fibrinolytic Agents; Hemorrhage; Hemostasis; Leukocytes; Mesentery; Microcirculation; Thrombin

Topics: Animals; Aorta; Blood Cell Count; Blood Flow Velocity; Blood Platelets; Capillary Permeability; Cats; Cell Adhesion; Cell Aggregation; Constriction; Fibrin; Hemorrhage; Hindlimb; Leukocyte Count; Leukocytes; Microcirculation; Microscopy, Electron; Muscles

Topics: Acute Disease; Adult; Aged; Blood Coagulation Factors; Blood Coagulation Tests; Blood Platelets; Chronic Disease; Disseminated Intravascular Coagulation; Ecchymosis; Ethanol; Female; Fibrin; Fibrinolysis; Hemorrhage; Hemostasis; Humans; Male; Middle Aged; Mucous Membrane; Protamines; Prothrombin Time; Syndrome; Thrombocytopenia

Topics: Aged; Aminosalicylic Acids; Antibodies; Antigen-Antibody Reactions; Binding Sites; Binding, Competitive; Blood Coagulation; Blood Coagulation Tests; Calcium; Enzyme Activation; Factor XIII; Female; Fibrin; Hemorrhage; Humans; Isoniazid; Male; Middle Aged; Peptides; Tuberculosis

Topics: Blood Coagulation; Blood Platelets; Cadaverine; Child; Cross Reactions; Dansyl Compounds; Enzyme Activation; Factor XIII; Factor XIII Deficiency; Female; Fibrin; Glutamine; Hematoma; Hemorrhage; Heterozygote; Humans; Immunodiffusion; Immunoelectrophoresis; Male; Polymorphism, Genetic; Pregnancy; Transferases; Umbilical Cord

Topics: Afibrinogenemia; Animals; Antibodies; Fibrin; Fibrinogen; Hemorrhage; Humans; Immune Sera; Immunoelectrophoresis; Rabbits; Thromboembolism; Thrombosis

Topics: Adult; Aged; Arteriosclerosis; Autopsy; Blood Platelets; Calcinosis; Cholesterol; Coronary Disease; Coronary Vessels; Embolism; Erythrocytes; Female; Fibrin; Heart Ventricles; Hemorrhage; Humans; Leukocytes; Male; Middle Aged; Myocardial Infarction; Myocardium; Thrombosis; Time Factors

Topics: Acute Disease; Adolescent; Adult; Aged; Blood Coagulation Disorders; Blood Coagulation Tests; Child; Child, Preschool; Exchange Transfusion, Whole Blood; Factor V Deficiency; Factor VII Deficiency; Female; Fibrin; Fibrinolysis; Hemorrhage; Hemostasis; Hepatitis A; Humans; Hypoprothrombinemias; Liver Diseases; Liver Function Tests; Male; Middle Aged; Plasminogen; Prothrombin Time

Topics: Blood Coagulation Tests; Cardiac Surgical Procedures; Disseminated Intravascular Coagulation; Extracorporeal Circulation; Fibrin; Fibrinogen; Hemorrhage; Heparin; Humans; Time Factors

Topics: Abortion, Legal; Afibrinogenemia; Amnion; Blood Coagulation; Blood Platelets; Cell Count; Female; Fibrin; Fibrinogen; Hemorrhage; Humans; Hypertonic Solutions; Injections; Pregnancy; Prothrombin Time; Sodium Chloride

Topics: Adolescent; Adult; Aged; Burns; Child; Child, Preschool; Clot Retraction; Fibrin; Fibrinogen; Hemagglutination Inhibition Tests; Hemorrhage; Humans; Immunoassay; Length of Stay; Middle Aged; Prothrombin

Topics: Animals; Antigens; Bacterial Infections; Brain; Cross Reactions; Demyelinating Diseases; Disease Models, Animal; Edema; Encephalomyelitis, Autoimmune, Experimental; Exudates and Transudates; Fibrin; Guinea Pigs; Haplorhini; Hemorrhage; Heparin; Humans; Immunization, Passive; Inflammation; Leukocytes; Lymphocytes; Multiple Sclerosis; Myelin Sheath; Pertussis Vaccine; Proteins; Rats; Virus Diseases

Topics: Adrenal Glands; Asphyxia Neonatorum; Blood Cell Count; Blood Coagulation Disorders; Blood Platelets; Disseminated Intravascular Coagulation; Embryonic and Fetal Development; Fibrin; Fibrinogen; Hemorrhage; Humans; Hypothermia; Infant, Newborn; Liver; Respiration, Artificial; Thromboembolism; Vitamin K Deficiency

Topics: Aged; Anticoagulants; Autopsy; Capillaries; Dextrans; Embolism; Female; Fibrin; Hemorrhage; Humans; Infusions, Parenteral; Kidney Glomerulus; Male; Postoperative Complications; Transfusion Reaction

Topics: Autopsy; Blood Cell Count; Blood Coagulation Factors; Blood Coagulation Tests; Blood Platelets; Blood Vessels; Cerebral Hemorrhage; Disseminated Intravascular Coagulation; Erythroblastosis, Fetal; Female; Fibrin; Fibrinogen; Hemoglobins; Hemorrhage; Humans; Infant, Newborn; Liver; Lung; Pregnancy; Retrospective Studies; Subarachnoid Hemorrhage; Thrombin; Thromboplastin

Topics: Adrenal Glands; Adrenal Medulla; Autopsy; Blood Cell Count; Child; Child, Preschool; Disseminated Intravascular Coagulation; Female; Fibrin; Hemorrhage; Heparin; Histocytochemistry; Humans; Infant; Kidney; Kidney Glomerulus; Length of Stay; Male; Shock; Waterhouse-Friderichsen Syndrome

Topics: Animals; Bone Marrow; Chemical and Drug Induced Liver Injury; Feces; Femur; Fibrin; Hemorrhage; Indium; Ions; Kidney; Kidney Tubules; Liver; Lung; Male; Mercury; Mice; Muscles; Necrosis; Oxides; Phagocytosis; Protein Binding; Spleen; Thrombocytopenia; Thrombosis; Water

Topics: Blood Coagulation Tests; Fibrin; Fibrinogen; Fibrinolysis; Hemorrhage; Humans; Male; Relapsing Fever; Tetracycline

Topics: Animals; Blood Coagulation; Blood Coagulation Factors; Blood Transfusion; Disseminated Intravascular Coagulation; Endotoxins; Female; Fibrin; Fibrinogen; Fibrinolysis; Hemorrhage; Humans; Pregnancy; Pregnancy Complications, Cardiovascular; Shock; Surface-Active Agents; Surgical Procedures, Operative; Thrombosis; Venoms

Topics: Adolescent; Adult; Blood Coagulation Disorders; Bone Marrow; Brain; Disseminated Intravascular Coagulation; Female; Fibrin; Fibrinogen; Hemorrhage; Humans; Kidney Glomerulus; Leukemia, Myeloid, Acute; Liver; Lymph Nodes; Male; Middle Aged; Pulmonary Edema; Skin; Spleen

Topics: Autopsy; Blister; Blood Coagulation Disorders; Duodenal Ulcer; Fibrin; Hemorrhage; Histocytochemistry; Humans; Infant; Kidney Glomerulus; Lung Diseases; Male; Mast Cells; Peptic Ulcer Hemorrhage; Shock, Hemorrhagic; Skin; Thrombosis; Urticaria Pigmentosa

Topics: Autopsy; Blood Coagulation Disorders; Blood Coagulation Factors; Blood Coagulation Tests; Fibrin; Fibrinogen; Fibrinolysis; Hemorrhage; Hepatitis A; Humans; Thrombocytopenia

Topics: Autopsy; Blood Cell Count; Blood Coagulation Disorders; Blood Coagulation Tests; Blood Platelets; Cytopathogenic Effect, Viral; Erythrocytes; Fibrin; Fibrinogen; Hemorrhage; Herpes Simplex; Humans; Infant, Newborn; Infant, Newborn, Diseases; Prothrombin Time

Topics: Aminocaproates; Animals; Blood Cell Count; Blood Coagulation Disorders; Blood Coagulation Factors; Blood Coagulation Tests; Blood Platelets; Chickens; Comb and Wattles; Disseminated Intravascular Coagulation; Fibrin; Hemorrhage; Heparin; Influenza in Birds; Liver; Lung; Myocardium; Spleen; Thrombelastography; Virus Diseases

Topics: Animals; Blood; Blood Coagulation; Chlorides; Chromium Isotopes; Erythrocytes; Fibrin; Fibrinogen; Hemoglobins; Hemorrhage; Humans; Iodine Isotopes; Iron; Iron Isotopes; Photography; Rabbits; Vitreous Body

Topics: Asphyxia; Bronchitis; Chloramphenicol; Endoscopy; Fibrin; Hemorrhage; Humans; Mucous Membrane; Tracheal Diseases; Tracheotomy

Topics: Aminocaproates; Antifibrinolytic Agents; Benzoates; Blood Coagulation Disorders; Blood Coagulation Tests; Blood Platelet Disorders; Cyclohexanecarboxylic Acids; Factor V; Factor V Deficiency; Factor VIII; Fibrin; Fibrinolysis; Hemagglutination Tests; Hemorrhage; Heparin; Humans; Immunodiffusion; Immunoelectrophoresis; Plasminogen; Streptokinase; Thrombocytopenia

Topics: Adolescent; Adult; Age Factors; Aged; Animals; Anticoagulants; Arthritis, Rheumatoid; Blood Coagulation Disorders; Blood Coagulation Factors; Blood Coagulation Tests; Blood Platelets; Cardiovascular Diseases; Cattle; Child; Child, Preschool; Dogs; Electrophoresis; Female; Fibrin; Fibrinolysin; Fibrinolysis; Fibrinolytic Agents; Hemorrhage; Hemorrhagic Disorders; Humans; Infant; Male; Menstruation; Methods; Middle Aged; Neoplasms; Plasminogen; Pregnancy; Rabbits; Sex Factors; Thromboembolism; Thrombosis; Uremia

Topics: Acute Kidney Injury; Esophagus; Extracorporeal Circulation; Fibrin; Fibrinolysis; Hemorrhage; Hemorrhagic Disorders; Humans; Kidney; Lung; Pleura; Pneumonectomy; Postoperative Complications; Splenectomy; Thrombosis

Topics: Birth Weight; Blood; Blood Coagulation Factors; Cesarean Section; Female; Fibrin; Hemorrhage; Humans; Immunoelectrophoresis; Infant, Newborn; Infant, Newborn, Diseases; Infant, Premature; Infections; Labor Presentation; Labor, Obstetric; Maternal-Fetal Exchange; Pregnancy; Respiratory Distress Syndrome, Newborn; Time Factors; Umbilical Cord

Topics: Adrenal Cortex Hormones; Afibrinogenemia; Asphyxia Neonatorum; Ecchymosis; Exchange Transfusion, Whole Blood; Fibrin; Hemorrhage; Heparin; Humans; Infant, Newborn; Infant, Newborn, Diseases; Male; Penicillins; Respiration, Artificial

Topics: Arteriosclerosis; Blood Coagulation; Blood Coagulation Tests; Blood Platelets; Extracorporeal Circulation; Fibrin; Fibrinolysis; Hemorrhage; Heparin; Heparin Antagonists; Humans; Hyperlipidemias; Hypersensitivity; Natriuresis; Osteoporosis; Protamines; Prothrombin Time; Thromboembolism; Thrombophlebitis; Thromboplastin

Lewis et al. recently reported on a patient who died of hemorrhages attributable to an acquired inhibitor of fibrin-stabilizing factor. They indicated that the inhibitor was associated with the immune globulins. Using the postmortem serum in the isolated fibrin cross-linking system, we have now further localized the site of inhibition in the scheme of blood coagulation. The interference occurs at the transpeptidation step catalyzed by the thrombin-activated fibrin-stabilizing factor. The patient's serum also uniquely delayed the clotting time of Homarus plasma, a test for specific inhibitors of transpeptidation. Since the inhibitor was effective in two such widely different systems, it probably is not an antibody, but falls into the category of cross-linking inhibitors which we have previously described (4, 5, 10, 12-17). While the exact nature of the inhibitor remains unknown, we raise the question whether some unusual metabolic transformation of isonicotinic acid hydrazide (with which the patient was treated and which itself we found to be a potent inhibitor fibrin cross-linking), in combination with a macromolecule, might not have given rise to an inhibitory compound.

Topics: Animals; Blood Coagulation Disorders; Cross-Linking Reagents; Fatal Outcome; Fibrin; Hemorrhage; Humans; Nephropidae

Topics: Adolescent; Adult; Aortic Valve Insufficiency; Biological Assay; Blood Coagulation; Cardiac Surgical Procedures; Child; Child, Preschool; Extracorporeal Circulation; Female; Fibrin; Fibrinolysis; Heart Septal Defects; Hemorrhage; Humans; Male; Middle Aged; Mitral Valve Insufficiency

Topics: Anemia, Aplastic; Child; Eye Diseases; Female; Fibrin; Hemorrhage; Humans; Retina; Retinal Detachment; Retinal Hemorrhage; Vitreous Body

Topics: Death, Sudden; Fibrin; Fibrinolysis; Fluorescent Antibody Technique; Forensic Medicine; Hemorrhage; Histocytochemistry; Humans; Immunochemistry; Phosphotungstic Acid; Skin

Topics: Aminocaproates; Antifibrinolytic Agents; Aprotinin; Culture Techniques; Decidua; Endometrium; Female; Fibrin; Fibrinolysis; Genital Diseases, Female; Genital Neoplasms, Female; Hemorrhage; Humans; Methods; Placenta; Pregnancy; Thrombelastography; Uterine Cervical Neoplasms; Uterine Neoplasms; Uterus

Topics: Afibrinogenemia; Blood Coagulation Tests; Blood Platelets; Embolism; Factor V; Factor VIII; Female; Fibrin; Fibrinogen; Hemorrhage; Humans; Immunoelectrophoresis; Pregnancy; Pregnancy Complications, Hematologic; Thrombelastography

Topics: Animals; Fibrin; Fluorescent Antibody Technique; Hemorrhage; Humans; Rabbits

Topics: Blood Coagulation Disorders; Child; Female; Fibrin; Hemorrhage; Humans

Topics: Adaptation, Biological; Afibrinogenemia; Blood Coagulation Factors; Blood Platelet Disorders; Blood Platelets; Capillaries; Fibrin; Hemophilia A; Hemorrhage; Humans; Physiology; Thrombocytopenia; Thrombocytosis

Topics: Fibrin; Fibrin Foam; Hemorrhage; Hemostatics; Humans; Jugular Veins; Postoperative Complications; Stapes Surgery

Topics: Aminocaproates; Aminocaproic Acid; Amniotic Fluid; Blood Coagulation Disorders; Blood Coagulation Tests; Blood Transfusion; Embolism; Embolism, Amniotic Fluid; Female; Fibrin; Fibrinolysin; Fibrinolysis; Gastrointestinal Hemorrhage; Hemorrhage; Humans; Male; Physiology; Plasminogen; Pregnancy; Prostatic Neoplasms

Topics: Blood Platelets; Capillaries; Cardiovascular System; Dogs; Fibrin; Heart, Artificial; Hemorrhage; Lung Injury; Pathology; Pulmonary Atelectasis; Pulmonary Embolism; Research

Topics: Abortion, Induced; Afibrinogenemia; Blood Transfusion; Curettage; Female; Fibrin; Genital Diseases, Female; Gynecology; Hemorrhage; Humans; Postpartum Hemorrhage; Postpartum Period; Pregnancy; Thrombin; Uterine Hemorrhage

Topics: Deoxyribonuclease I; Dogs; Endopeptidases; Fibrin; Fibrinolysin; Fibrinolytic Agents; Hemorrhage; Heparin; Pharmacology; Plasminogen; Research; Streptodornase and Streptokinase; Streptokinase; Thrombosis

Topics: Aging; Coloring Agents; Fibrin; Hemorrhage; Humans; Pathology; Research; Staining and Labeling; Wound Healing

Topics: Capillary Permeability; Female; Fibrin; Fibrinolysin; Fibrinolysis; Hemorrhage; Histamine; Humans; Postpartum Hemorrhage; Postpartum Period

Topics: Female; Fibrin; Hemorrhage; Humans; Polymerization; Postpartum Hemorrhage; Postpartum Period; Pregnancy

Topics: Afibrinogenemia; Female; Fibrin; Hemorrhage; Humans; Postpartum Hemorrhage; Postpartum Period; Pregnancy; Pregnancy Complications; Thromboplastin

Topics: Embolism; Embolism, Fat; Female; Fibrin; Hemorrhage; Hemorrhagic Disorders; Humans; Postpartum Hemorrhage; Postpartum Period; Pulmonary Embolism

Topics: Abruptio Placentae; Female; Fibrin; Fibrinolysis; Hemorrhage; Humans; Pregnancy; Pregnancy Complications

Topics: Fibrin; Fibrinolysis; Hemorrhage; Humans; Male; Prostatectomy

Topics: Fibrin; Hemorrhage; Surgical Procedures, Operative

Topics: Female; Fibrin; Fibrinogen; Hemorrhage; Hemostatics; Humans; Labor, Obstetric; Pregnancy

Topics: Fibrin; Fibrinolysis; Glycine max; Hemorrhage; Humans; Trypsin Inhibitors

Topics: Female; Fibrin; Hemorrhage; Hemorrhagic Disorders; Humans; Labor, Obstetric; Pregnancy

Topics: Fibrin; Fibrinolysis; Hemorrhage; Humans; Postoperative Hemorrhage

Topics: Coagulants; Female; Fibrin; Fibrinogen; Fibrinolysis; Hemorrhage; Hemostatics; Humans; Labor, Obstetric; Pregnancy

Topics: Amniotic Fluid; Embolism; Embolism, Amniotic Fluid; Female; Fibrin; Hemorrhage; Humans; Labor, Obstetric; Obstetrics; Pregnancy

Topics: Fibrin; Fibrinolysis; Hemorrhage; Humans; Kidney; Nephrectomy

Topics: Coagulants; Fibrin; Fibrinogen; Fibrinolysis; Hemorrhage; Hemostatics; Obstetrics; Surgical Procedures, Operative

Topics: Afibrinogenemia; Delivery, Obstetric; Female; Fibrin; Fibrinogen; Fibrinolysis; Hemorrhage; Hemorrhagic Disorders; Humans; Pregnancy

Topics: Amniotic Fluid; Fibrin; Hemorrhage; Hemorrhagic Disorders; Obstetric Labor Complications

Topics: Female; Fibrin; Hemorrhage; Hemorrhagic Disorders; Humans; Placenta; Pregnancy

Topics: Fibrin; Fibrinolysis; Hemorrhage; Humans; Male; Neoplasms; Prostatic Neoplasms; Syndrome

Topics: Abdomen; Fibrin; Hemorrhage; Humans; Leukemia; Leukemia, Myeloid; Spleen; Splenomegaly

Topics: Diagnostic Tests, Routine; Digestive System Surgical Procedures; Fibrin; Fibrinolysis; Gastrectomy; Hemorrhage; Humans; Stomach

Topics: Blood Coagulation; Fibrin; Hemorrhage; Hemorrhagic Disorders; Humans

Topics: Female; Fibrin; Hemorrhage; Hemorrhagic Disorders; Humans; Obstetric Labor Complications; Obstetrics; Pregnancy

Topics: Female; Fibrin; Hemorrhage; Humans; Menorrhagia; Metrorrhagia; Pregnancy; Syndrome; Thrombosis; Uterine Hemorrhage; Uterus

Topics: Abortion, Induced; Abortion, Spontaneous; Female; Fibrin; Hemorrhage; Humans; Pregnancy; Pregnancy Complications

Topics: Abruptio Placentae; Female; Fibrin; Hemorrhage; Humans; Placenta; Pregnancy; Stroke; Uterine Hemorrhage; Uterus

Topics: Fibrin; Fibrinolysis; Hemorrhage; Humans; Leukemia; Leukemia, Myeloid; Syndrome

Topics: Fibrin; Fibrinolysis; Hemorrhage; Hemorrhagic Disorders; Humans; Syndrome; Thrombolytic Therapy

Topics: Erythroblastosis, Fetal; Fetus; Fibrin; Fibrinogen; Hematologic Diseases; Hemorrhage; Humans; Infant, Newborn; Prothrombin

Topics: Blood Coagulation; Female; Fibrin; Fibrinolysis; Hemorrhage; Humans; Postpartum Hemorrhage; Postpartum Period; Pregnancy

Topics: Abortion, Induced; Abortion, Spontaneous; Female; Fibrin; Hemorrhage; Humans; Obstetrics; Pregnancy

Topics: Animals; Cattle; Fibrin; Fibrin Foam; Hemorrhage; Thromboplastin

Topics: Blood Coagulation; Fibrin; Hemorrhage; Hemostatics; Humans; Prothrombin

Topics: Blood; Fibrin; Hemorrhage; Humans

Topics: Blood; Blood Coagulation; Fibrin; Fibrin Foam; Hemorrhage; Hemostasis; Humans; Plasma; Thrombin