fibrin and Amyloidosis

Fibrinogen, a 340-kDa plasma protein, is composed of two identical molecular halves each consisting of three non-identical A alpha-, B beta- and gamma-chain subunits held together by multiple disulfide bonds. Fibrinogen is shown to have a trinodular structure; that is, one central nodule, the E domain, and two identical outer nodules, the D-domains, linked by two coiled-coil regions. After activation with thrombin, a pair of binding sites comprising Gly-Pro-Arg is exposed in the central nodule and combines with its complementary binding site a in the outer nodule of another molecules. By using crystallographic analysis, the alpha-amino group of alpha Gly-1 is shown to be juxtaposed between gamma Asp-364 and gamma Asp-330, and guanidino group of alpha Arg-3 between the carboxyl group of gamma Asp-364 and gamma Gln-329 in the a site. Half molecule-staggered, double-stranded protofibrils are thus formed. Upon abutment of two adjacent D domains on the same strand, D-D self association takes place involving Arg-275, Tyr-280, and Ser-300 of the gamma-chain on the surface of the abutting two D domains. Thereafter, carboxyl-terminal regions of the alpha-chains are untethered and interact with those of other protofibrils leading to the formation of thick fibrin bundles and networks. Although many enigmas still remain concerning the exact mechanisms of these molecular interactions, fibrin assembly proceeds in a highly ordered fashion. In this review, these molecular interactions of fibrinogen and fibrin are discussed on the basis of the data provided by hereditary dysfibrinogens on introducing representative molecules at each step of fibrin clot formation.

Topics: Amino Acid Sequence; Amyloidosis; Base Sequence; Fibrin; Fibrinogen; Humans; Kidney Diseases; Microscopy, Electron, Scanning; Molecular Sequence Data

Cardiovascular imaging is evolving in response to systemwide trends toward molecular characterization and personalized therapies. The development of new radiotracers for PET and SPECT imaging is central to addressing the numerous unmet diagnostic needs that relate to these changes. In this 2-part review, we discuss select radiotracers that may help address key unmet clinical diagnostic needs in cardiovascular medicine. Part 1 examined key technical considerations pertaining to cardiovascular radiotracer development and reviewed emerging radiotracers for perfusion and neuronal imaging. Part 2 covers radiotracers for imaging cardiovascular inflammation, thrombosis, fibrosis, calcification, and amyloidosis. These radiotracers have the potential to address several unmet needs related to the risk stratification of atheroma, detection of thrombi, and the diagnosis, characterization, and risk stratification of cardiomyopathies. In the first section, we discuss radiotracers targeting various aspects of inflammatory responses in pathologies such as myocardial infarction, myocarditis, sarcoidosis, atherosclerosis, and vasculitis. In a subsequent section, we discuss radiotracers for the detection of systemic and device-related thrombi, such as those targeting fibrin (e.g.,

Topics: Amyloidosis; Calcinosis; Fibrin; Fibrosis; Humans; Inflammation; Positron-Emission Tomography; Thrombosis

Gingival hyperplasia may be genetic, may be acquired as a consequence of exposure to drugs and other agents or may appear as part of a more widespread disorder. Five patients who acquired gingival hyperplasia due to amyloidaceous deposits staining only for fibrin are presented. This appears to be a new entity related to ligneous conjunctivitis.

Topics: Adolescent; Adult; Amyloidosis; Child; Child, Preschool; Conjunctivitis; Female; Fibrin; Gingival Hyperplasia; Humans; Male

Topics: alpha-2-Antiplasmin; Amyloidosis; Chemical Phenomena; Chemistry, Physical; Disseminated Intravascular Coagulation; Fibrin; Humans; Lupus Erythematosus, Systemic; Plasminogen; Protein Binding

25 cases of primary cutaneous amyloidosis are studied. 16 patients had macular amyloidosis (MPA) and 9 lichen amyloidosus (LPA). gamma-Globulins were increased in 50% of the patients. IgG and IgA were increased in the serum of 5 and 3 patients with MPA and 4 and 2 patients with LPA, respectively. Volume of amyloid deposits was similar in both forms. By direct immunofluorescence we demonstrated IgG in the amyloid deposits of 21 of the 25 cases and C3 in 13; IgM was present in 9 cases of MPA and in 3 cases of LPA. MPA was more frequent than LPA; histologically, it was impossible to distinguish MPA from LPA; correlation between serum levels of gamma-globulins and their presence in amyloid deposits was weak; MPA and LPA seem to be distinct clinical manifestations of the same disease and itching does not cause transformation of MPA in LPA.

Topics: Amyloidosis; Complement C3; Female; Fibrin; Fibrinogen; Fluorescent Antibody Technique; Humans; Immunoglobulin A; Immunoglobulin E; Immunoglobulin G; Immunoglobulin M; Male; Middle Aged; Skin Diseases

Topics: Amyloidosis; Arthritis, Juvenile; Blood Platelets; Child; Disseminated Intravascular Coagulation; Fibrin; Fibrinogen; Hemorrhagic Disorders; Humans

The urinary concentration of fibrin-fibrinogen degradation products (F.D.P.) was measured in 90 patients with proteinuria above 2 g/1 and correlated with proteinuria, differential protein clearances, serum urea and creatinine, and renal biopsy findings. There was a linear correlation (r equals 0-7; P less than 0-001) between the urinary F.D.P. excretion and the selectivity of the proteinuria such that patients with highly selective proteinuria excreted only small amounts of F.D.P. whereas those with non-selective proteinuria excreted much higher levels. There was a significant correlation between the urinary F.D.P. excretion and the urine:serum (U:S) ratio of IgG excretion but not with the U:S ratio or urinary excretion of albumin or transferrin. Sephadex G200 column chromatography of the concentrated urine in 26 cases showed that patients with highly selective proteinuria excreted predominantly F.D.P. of low molecular weight in the urine whereas those with non-selective proteinuria excreted mainly fibrinogen and products of high molecular weight. Hence the type and quantity of F.D.P. in the urine are determined primarily by the differential filtration of fibrinogen and the various degradation products from the plasma through the glomerular basement membrane, which in turn is determined by the "pore size" of the basement membrane. In clinical nephrology measurement of the urinary F.D.P. level provides a rapid and convenient means of estimating the differential protein clearance.

Topics: Albuminuria; Amyloidosis; Chromatography; Fibrin; Fibrinogen; Filtration; Glomerular Filtration Rate; Glomerulonephritis; Humans; Hypersensitivity; Hypertension, Malignant; Immunodiffusion; Immunoglobulin G; Lupus Erythematosus, Systemic; Molecular Weight; Nephrotic Syndrome; Proteinuria; Purpura; Thrombosis; Transferrin

This describes the sodium sulphate-Alcian Blue (SAB) method for staining amyloid in paraffin sections. Its value lies in the possibility of subsequent counterstaining and thus of revealing the structural relationships of amyloid. In the kidney the topical disposition of amyloid closely resembles the disposition of fibrin in the kidney of diabetics; this suggests that upset in vascular permeability plays a part in determining the site of the amyloid deposits. Furthermore, an aging process in amyloid can now be envisaged resembling the aging of extraluminal fibrin. Both materials proceed to a hyalin material that, staining like collagen, merits the name pseudo-collagen. This term we apply to a hyalin, staining like collagen, for which, we can postulate a specific precursor.

Topics: Amyloid; Amyloidosis; Collagen; Diabetes Mellitus; Diabetic Angiopathies; Fibrin; Histological Techniques; Humans; Hyalin; Kidney; Kidney Diseases; Microscopy; Staining and Labeling

Topics: Amyloid; Amyloidosis; Biopsy; Fibrin; Fluorescent Antibody Technique; Histocytochemistry; Humans; Intestinal Mucosa; Microscopy, Electron; Rectum; Staining and Labeling; Tryptophan; Tyrosine

Topics: Aged; Amyloid; Amyloidosis; Diffuse Cerebral Sclerosis of Schilder; Fibrin; Fluorescent Antibody Technique; gamma-Globulins; Humans

Topics: Agglutination; Amyloidosis; Antigen-Antibody Reactions; Arthus Reaction; Chemical Precipitation; Fibrin; Glomerulonephritis; Humans; Hypersensitivity, Delayed; Hypersensitivity, Immediate; Lysogeny; Microscopy, Electron

Topics: Amyloid; Amyloidosis; Animals; Antigen-Antibody Reactions; Chemical Precipitation; Fibrin; Fibrinogen; Fluorescent Antibody Technique; Kidney; Rabbits; Spleen

Topics: Amyloidosis; Animals; Fibrin; Fluorescent Antibody Technique; Rabbits; Spleen