warfarin and Vitamin-K-Deficiency

Chronic kidney disease (CKD) patients have a higher risk of cardiovascular (CVD) morbidity and mortality compared to the general population. The links between CKD and CVD are not fully elucidated but encompass both traditional and uremic-related risk factors. The term CKD-mineral and bone disorder (CKD-MBD) indicates a systemic disorder characterized by abnormal levels of calcium, phosphate, PTH and FGF-23, along with vitamin D deficiency, decreased bone mineral density or altered bone turnover and vascular calcification. A growing body of evidence shows that CKD patients can be affected by subclinical vitamin K deficiency; this has led to identifying such a condition as a potential therapeutic target given the specific role of Vitamin K in metabolism of several proteins involved in bone and vascular health. In other words, we can hypothesize that vitamin K deficiency is the common pathogenetic link between impaired bone mineralization and vascular calcification. However, some of the most common approaches to CKD, such as (1) low vitamin K intake due to nutritional restrictions, (2) warfarin treatment, (3) VDRA and calcimimetics, and (4) phosphate binders, may instead have the opposite effects on vitamin K metabolism and storage in CKD patients.

Topics: Calcium; Fibroblast Growth Factor-23; Fibroblast Growth Factors; Humans; Hyperparathyroidism; Osteocalcin; Phosphates; Renal Insufficiency, Chronic; Risk Factors; Vascular Calcification; Vitamin K; Vitamin K Deficiency; Warfarin

Vascular calcification is a known complication of chronic kidney disease (CKD). The prevalence of vascular calcification in patients with non-dialysis-dependent CKD stages 3-5 has been shown to be as high as 79% (20). Vascular calcification has been associated with increased risk for mortality, hospital admissions, and cardiovascular disease (6, 20, 50, 55). Alterations in mineral and bone metabolism play a pivotal role in the pathogenesis of vascular calcification in CKD. As CKD progresses, levels of fibroblast growth factor-23, parathyroid hormone, and serum phosphorus increase and levels of 1,25-(OH)

Topics: Animals; Anticoagulants; Arteries; Dietary Supplements; Humans; Iatrogenic Disease; Renal Dialysis; Renal Insufficiency, Chronic; Risk Factors; Signal Transduction; Vascular Calcification; Vitamin K; Vitamin K Deficiency; Warfarin

Vitamin K is a composite term referring to a group of fat-soluble vitamins that function as a cofactor for the enzyme γ-glutamyl carboxylase (GGCX), which activates a number of vitamin K-dependent proteins (VKDPs) involved in haemostasis and vascular and bone health. Accumulating evidence demonstrates that chronic kidney disease (CKD) patients suffer from subclinical vitamin K deficiency, suggesting that this represents a population at risk for the biological consequences of poor vitamin K status. This deficiency might be caused by exhaustion of vitamin K due to its high requirements by vitamin K-dependent proteins to inhibit calcification.

Topics: Bone and Bones; Carbon-Carbon Ligases; Dietary Supplements; Humans; Nutritional Status; Randomized Controlled Trials as Topic; Renal Insufficiency, Chronic; Vitamin K; Vitamin K Deficiency; Warfarin

The incidence of venous thromboembolism (VTE) is increasing in the pediatric population. Individuals with cystic fibrosis (CF) have an increased risk of thrombosis due to central venous catheters (CVCs), as well as acquired thrombophilia secondary to inflammation, or deficiencies of anticoagulant proteins due to vitamin K deficiency and/or liver dysfunction. CVC-associated thrombosis commonly results in line occlusion, but may develop into serious life-threatening conditions such as deep venous thrombosis (DVT), superior vena cava syndrome or pulmonary embolism (PE). Post-thrombotic syndrome (PTS) may be a long complication. Local occlusion of the catheter tip may be managed with instillation of thrombolytics (such as tPA) within the lumen of the catheter; however, CVC-associated thrombosis involving the proximal veins is most often is treated with systemic anticoagulation. Initial treatment with heparin is a standard approach, but thrombolytic therapy, which may carry higher bleeding risks, should be considered for life and limb threatening episodes of VTE. Recommended duration of anticoagulation with low molecular weight heparin (LMWH) or warfarin ranges from 3 to 6 months for major removable thrombotic risks; longer anticoagulation is considered for recurrent thrombosis, major persistent thrombophilia, or the continued presence of a major risk factor such as a CVC. While CVCs are the most common risk for development of VTE in children, studies have not demonstrated a clear benefit with routine use of systemic thromboprophylaxis. The incidence and risk factors of VTE in CF patients will be reviewed and principles of diagnosis and management will be summarized.

Topics: Anticoagulants; Catheterization, Central Venous; Child; Cystic Fibrosis; Heparin, Low-Molecular-Weight; Humans; Incidence; Risk; Thrombophilia; Treatment Outcome; Venous Thromboembolism; Vitamin K Deficiency; Warfarin

The considerable variability in the warfarin dose-response relationship between individuals, is explained mainly by genetic variation in its major metabolic (CYP2C9) and target (VKORC1) enzymes. Despite the predominance of pharmacogenetics, environmental factors also affect the pharmacokinetics and pharmacodynamics of warfarin, and are often overlooked. Among these factors, dietary and supplemental vitamin K consumption is a controllable contributor to within-, and between-patient variability of warfarin sensitivity. In this commentary we review the current role of vitamin K in warfarin anticoagulation therapy, with emphasis on the following: 1 The effect of dietary and supplemental vitamin K on warfarin anticoagulation, beyond the impact of genetic variability in CYP2C9 and VKORC1. We deal separately with the effects of vitamin K on warfarin dose requirements during the induction of therapy, as opposed to its effect on stability of anticoagulation control during maintenance therapy. 2 The role of vitamin K supplementation in warfarin treated patients with vitamin K deficiency as well as in patients with unstable warfarin anticoagulation, and 3 The role of therapeutic vitamin K in cases of warfarin over-anticoagulation.

Topics: Anticoagulants; Aryl Hydrocarbon Hydroxylases; Blood Coagulation; Cytochrome P-450 CYP2C9; Dietary Supplements; Dose-Response Relationship, Drug; Drug Interactions; Humans; Mixed Function Oxygenases; Mutation; Vitamin K; Vitamin K Deficiency; Vitamin K Epoxide Reductases; Warfarin

The interaction potential between warfarin and cranberry juice is discussed.. Reports from the United Kingdom have raised concern over the interaction potential between cranberry juice and warfarin. Warfarin is the most commonly prescribed oral medication for anticoagulation therapy. Cranberry juice is a flavonoid, which has been shown to induce, inhibit, or act as a substrate for the biosynthesis of several cytochrome P-450 (CYP) isoenzymes. Specifically, cranberry juice may inhibit the activity of CYP2C9, the primary isoenzyme involved in the metabolism of S-warfarin. A search of the medical literature identified three peer-reviewed case reports and two peer-reviewed, prospective, randomized, placebo-controlled clinical trials using metabolic surrogates of warfarin (flurbiprofen and cyclosporine) that described possible interactions between cranberry juice and warfarin. Two case reports suggested that cranberry juice increased the International Normalized Ratio (INR) of patients taking warfarin, but neither clearly identified cranberry juice as the sole cause of INR elevation. One case report appeared to show a correlation between the effects of cranberry juice and warfarin metabolism. Both clinical trials indicated the lack of an interaction between cranberry juice and CYP isoenzymes 2C9 and 3A, both of which are necessary in warfarin metabolism. More studies are required to determine the potential interaction between cranberry juice and warfarin.. The available data do not seem to show a clinically relevant interaction between cranberry juice and warfarin; however, patients taking warfarin with cranberry juice should be cautioned about the potential interaction and monitored closely for INR changes and signs and symptoms of bleeding.

Topics: Anticoagulants; Aryl Hydrocarbon Hydroxylases; Beverages; Clinical Trials as Topic; Cytochrome P-450 CYP2C9; Drug Monitoring; Female; Flavonoids; Food-Drug Interactions; Hemorrhage; Humans; International Normalized Ratio; Male; Vaccinium macrocarpon; Vitamin K Deficiency; Warfarin

Vitamin K, discovered in the 1930s, functions as cofactor for the posttranslational carboxylation of glutamate residues. Gammacarboxy glutamic acid (Gla)-residues were first identified in prothrombin and coagulation factors in the 1970s; subsequently, extra-hepatic Gla proteins were described, including osteocalcin and matrix Gla protein (MGP). Impairment of the function of osteocalcin and MGP due to incomplete carboxylation results in an increased risk for developing osteoporosis and vascular calcification, respectively, and is an unexpected side effect of treatment with oral anticoagulants. It is conceivable that other side effects, possible involving growth-arrest-specific gene 6 (Gas6) protein will be identified in forthcoming years. In healthy individuals, substantial fractions of osteocalcin and MGP circulate as incompletely carboxylated species, indicating that the majority of these individuals is subclinically vitamin K-deficient. Potential new application areas for vitamin K are therefore its use in dietary supplements and functional foods for healthy individuals to prevent bone and vascular disease, as well as for patients on oral anticoagulant treatment to offer them protection against coumarin-induced side effects and to reduce diet-induced fluctuations in their INR values.

Topics: Animals; Blood Coagulation; Calcium-Binding Proteins; Drug Therapy, Combination; Extracellular Matrix Proteins; Humans; Matrix Gla Protein; Vitamin K; Vitamin K Deficiency; Warfarin

Topics: Animals; Anticoagulants; Calcinosis; Chronic Disease; Humans; Renal Dialysis; Renal Insufficiency; Vascular Diseases; Vitamin K; Vitamin K Deficiency; Warfarin

Topics: Anticoagulants; Blood Coagulation Tests; Coagulation Protein Disorders; Disseminated Intravascular Coagulation; Drug Monitoring; Humans; Liver Diseases; Reference Values; Specimen Handling; Vitamin K Deficiency; Warfarin

Topics: Anemia, Iron-Deficiency; Copper; Folic Acid Deficiency; Hematologic Diseases; Humans; Nutrition Assessment; Nutritional Physiological Phenomena; Vitamin B 12 Deficiency; Vitamin K Deficiency; Warfarin

Topics: Abnormalities, Drug-Induced; Abnormalities, Multiple; Calcinosis; Diagnosis, Differential; Epiphyses; Female; Fetal Diseases; Humans; Infant, Newborn; Nose; Pregnancy; Prenatal Exposure Delayed Effects; Prognosis; Syndrome; Vitamin K Deficiency; Warfarin

Topics: Anti-Bacterial Agents; Anticoagulants; Diagnosis, Differential; Digestive System Diseases; Female; Hemorrhage; Humans; Infant; Infant, Newborn; Pregnancy; Prognosis; Vitamin K Deficiency; Warfarin

Dicoumarol was found to be the causative agent of a haemorrhagic disease in cattle following the ingestion of spoiled sweet clover. Vitamin K deficiency in chickens caused bleeding. Dicoumarol was later determined to be a vitamin K antagonist. A more potent form of the drug was produced synthetically and, following its initial use as rat poison, was recognized as a potential anti-thrombotic treatment in humans. The mode of action of a coumarin derivative (i.e. warfarin) is described. The overall effect of high-dose and low-dose warfarin and the possibility of a transient state of hypercoagulability on the introduction and withdrawal of treatment is considered.

Topics: Animals; Anticoagulants; Blood Coagulation Factors; Coumarins; Hemostasis; Humans; Protein C; Protein S; Vitamin K; Vitamin K Deficiency; Warfarin

The microsomal mixed function oxidase system metabolizes xenobiotics (Phase I) to products that, if not activated and conjugated for excretion (Phase II), are capable of forming conjugates with cellular macromolecules, including DNA, resulting in toxic, mutagenic, or carcinogenic events. Benzo(a)pyrene (BP), a polycyclic aromatic hydrocarbon, is a model carcinogen for this system. Vitamin K1 (phylloquinone) is a regulator of BP metabolism. These studies demonstrate that K1 is capable of increasing Phase I metabolism and decreasing glutathione transferase activity (Phase II) in chick embryo liver; that deprivation of K1 reduces BP/DNA adducts in mouse liver and reduces tumor formation in mice given intraperitoneal BP; and that K1 supplementation increases BP induced tumor formation in mice. However, epidemiologic studies indicate that children of mothers who smoke during pregnancy may not be at increased risk of cancer. It is known that the placentas from these pregnancies exhibit markedly increased levels of arylhydrocarbon hydroxylase induced by the polycyclic aromatic hydrocarbons in tobacco smoke, but there is no corresponding increase in this enzyme activity in the fetus in such pregnancies. We suggest that the low vitamin K level is a secondary protective mechanism for xenobiotics, such as BP, that may escape the primary placental screen. The recently described role of vitamin K-dependent Gla protein as ligands for receptor tyrosine kinases, also establishes K as a link in cell growth and transformation. It is proposed that the small total body pool of K1 in the adult, which is sufficient only to meet continuing needs, and the even smaller pool in the fetus are protective. This protective effect of low K1 levels is particularly important in the presence of the high mitotic rates and rapid cell turnover in the avian embryo and mammalian fetus.

Topics: 7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide; Adult; Animals; Biotransformation; Carcinogens; Chick Embryo; Cocarcinogenesis; DNA Adducts; Female; Fetal Diseases; Fetus; Humans; Infant, Newborn; Liver; Maternal Exposure; Maternal-Fetal Exchange; Mice; Mice, Inbred ICR; Microsomes, Liver; Mixed Function Oxygenases; Neoplasms; Neoplasms, Experimental; Placenta; Pregnancy; Prenatal Exposure Delayed Effects; Smoking; Vitamin K; Vitamin K 1; Vitamin K Deficiency; Warfarin; Xenobiotics

Punctate epiphyses are caused by a diverse group of conditions. They may be an inherited part of certain bone dysplasias or an incidental finding occurring occasionally in various disorders. The pattern of the puncta together with other radiologic findings aid in making the correct diagnosis.

Topics: Child; Child, Preschool; Chondrodysplasia Punctata; Epiphyses; Female; Genetic Linkage; Humans; Infant; Infant, Newborn; Male; Pregnancy; Prenatal Exposure Delayed Effects; Radiography; Vitamin K Deficiency; Warfarin; X Chromosome; Zellweger Syndrome

Topics: Adult; Animals; Blood Coagulation Factors; Drug Interactions; Humans; Male; Vitamin E; Vitamin K; Vitamin K 1; Vitamin K Deficiency; Warfarin

Topics: Administration, Oral; Animals; Anticoagulants; Blood Coagulation; Blood Coagulation Factors; Blood Proteins; Clofibrate; Coumarins; Dicumarol; Disulfiram; Ethyl Biscoumacetate; Female; Heparin; Intestinal Absorption; Liver; Phenylbutazone; Protein Binding; Prothrombin; Prothrombin Time; Rabbits; Rats; Salicylates; Sulfonamides; Vitamin K; Vitamin K Deficiency; Warfarin

Topics: Amino Acids; Animals; Cycloheximide; Enzyme Precursors; Liver; Microsomes, Liver; Models, Chemical; Prothrombin; Vitamin K; Vitamin K Deficiency; Warfarin

Topics: Administration, Oral; Animals; Anticoagulants; Barbiturates; Biological Transport; Blood Coagulation Factors; Clofibrate; Cycloheptanes; Depression, Chemical; Dicumarol; Disulfiram; Drug Interactions; Drug Synergism; Feces; Female; Half-Life; Humans; Hypoprothrombinemias; Infant, Newborn; Phenylbutazone; Pregnancy; Prothrombin Time; Rats; Receptors, Drug; Serum Albumin; Vitamin K Deficiency; Warfarin

Topics: Animals; Calcium; Cattle; Coumarins; Cross Reactions; Enzyme Activation; Enzyme Precursors; Ethers, Cyclic; Humans; Hypoprothrombinemias; Liver; Microsomes, Liver; Protein Binding; Prothrombin; Rats; Snakes; Venoms; Vitamin K; Vitamin K Deficiency; Warfarin

Topics: Anticoagulants; Biopsy; Blood Coagulation; Blood Coagulation Disorders; Blood Coagulation Factors; Blood Coagulation Tests; Drug Resistance; Drug Synergism; Factor IX; Factor VII; Factor X; Fibrinolysis; Humans; Liver; Liver Diseases; Prothrombin; Vitamin K; Vitamin K Deficiency; Warfarin

Use of chronic vitamin K antagonist (VKA) induces a long-term deficiency of vitamin K, which may cause arterial stiffness and bone-related disease. Switching from VKA to rivaroxaban could induce rapid sufficiency of vitamin K and improvement of arterial stiffness. The K2 SUMMIT-3 study is a multicenter, open-label, prospective, and randomized design. Patients with atrial fibrillation who have been taking VKA for more than 6 months but less than 10 years were randomly assigned to two groups; those switching from VKA to rivaroxaban and those continuing with VKA medication. The primary endpoint was the percentage difference of brachial-ankle pulse wave velocity (baPWV) in 3 months. A total of 77 patients were randomly assigned to receive rivaroxaban (n = 38) or VKA (n = 39). The average age was 74 ± 9 years. The duration for which VKA was prescribed prior to randomization was 90 ± 87 months.Abnormally high levels of Des-gamma carboxyprothrombin (PIVKA-II) or uncarboxylated osteocalcin (ucOC) indicating vitamin K insufficiency were observed in 100% or 82% of the patients at baseline but it reduced to 2% (p < 0.0001) or 55% (p = 0.01) at 3 months in the rivaroxaban group. To the contrary, theses data had no changes in the VKA group. The percentage difference in baPWV was - 1.4 ± 10.0% vs. 3.5 ± 14.7% in the rivaroxaban and the VKA groups, respectively. (p = 0.02). Switching from VKA to rivaroxaban resulted in rapid sufficiency of vitamin K and reduction of arterial stiffness in 3 months.

Topics: Aged; Aged, 80 and over; Anticoagulants; Atrial Fibrillation; Drug Substitution; Factor Xa Inhibitors; Female; Humans; Japan; Male; Middle Aged; Prospective Studies; Rivaroxaban; Time Factors; Treatment Outcome; Vascular Stiffness; Vitamin K Deficiency; Warfarin

Most multivitamin supplements contain far less vitamin K(1) than thought to affect warfarin anticoagulation. Having described 3 patients with multivitamin-warfarin interactions, we hypothesized that vitamin K(1)-depleted patients are sensitive to even small increments. Therefore, we compared the effect of a vitamin K(1)-containing multivitamin on warfarin anticoagulation between patients with low versus normal vitamin K(1) status. We screened 102 warfarin-treated patients and recruited nine with "low" (< 1.5 mcg/L, 10(th) percentile) (group 1) and 7 with "normal" (>4.5 mcg/L, median) (group 2) total vitamin K(1) plasma levels (vitamin K(1) + vitamin K(1) 2,3-epoxide). Patients received one multivitamin tablet containing 25 mcg of vitamin K(1) daily, for 4 weeks (period 1). A predefined algorithm was used to adjust warfarin doses if the INR was outside the therapeutic range. Patients requiring warfarin increments were then switched to 4 weeks of a vitamin K(1)-free multivitamin supplement (period 2). During period 1, subtherapeutic INRs occurred in 9/9 and 1/7 patients in group 1 and 2, respectively (p <0.001). In group 1, INR decreased by a median of 0.51 (p <0.01), and warfarin dose had to be raised by 5.3% (p <0.01), whereas INR and warfarin dose did not change significantly in group 2. During period 2 (7 patients), there were trends towards decreased total vitamin K(1) and rising INRs associated with significantly lower warfarin doses. We conclude that vitamin K(1)-containing multivitamins reduce INR in patients with low vitamin K(1) status. Our study suggests that vitamin K-depleted patients are sensitive to even small changes in vitamin K(1) intake.

Topics: Adult; Aged; Aged, 80 and over; Anticoagulants; Dietary Supplements; Drug Antagonism; Drug Monitoring; Female; Humans; International Normalized Ratio; Male; Middle Aged; Nonprescription Drugs; Vitamin K 1; Vitamin K Deficiency; Warfarin

This randomized, controlled study evaluated the bioavailability of phylloquinone from an intravenous lipid emulsion. A mild vitamin K deficiency was induced in 12 healthy adult men and women by dietary restriction of phylloquinone (40 microg/d, days 1-11) and by administration of warfarin (1.0 mg/d, days 5-11). On day 11, subjects received a 500-mL intravenous solution of either lipid or saline, both of which contained 154 microg phylloquinone. Bioavailability was assessed by serial measurements of plasma phylloquinone, vitamin K1-2,3-epoxide. PIVKA-II (proteins induced by vitamin K absence or antagonists-II), and percentage undercarboxylated osteocalcin. As a result of vitamin K deficiency and minidose warfarin, vitamin K1-2,3-epoxide, PIVKA-II, and percentage undercarboxylated osteocalcin increased significantly between days 1 and 11 (P = 0.05, 0.016, and 0.001, respectively). With the infusions, plasma phylloquinone increased in both groups (P = 0.001). After the infusions vitamin K,-2,3-epoxide decreased in both groups (P = 0.002). Changes in plasma phylloquinone and vitamin K1-2,3-epoxide were no different in the two groups (mean areas under the curves +/- SEM: 116+/-13 nmol x h/L for the saline group and 102+/-20 nmol x h/L for the lipid group for phylloquinone; 38.6+/-7.5 nmol x h/L for the saline group and 31.3+/-9.0 nmol x h/L for the lipid group for vitamin K1-2,3-epoxide). PIVKA-II decreased significantly from baseline values (P = 0.005) in both groups after the infusions. Intravenous lipid reversed the effects of minidose warfarin and of dietary restriction of phylloquinone on hemostasis and vitamin K nutritional status. This reversal was no different from that seen with the infusion of phylloquinone in a saline solution.

Topics: Adult; Biological Availability; Biomarkers; Diet; Fat Emulsions, Intravenous; Female; Humans; Male; Osteocalcin; Protein Precursors; Prothrombin; Vitamin K 1; Vitamin K Deficiency; Warfarin

Rats rendered lightly vitamin K deficient with warfarin (0.01 mg/100 g, IP) and given the equivalent of 1000 units of vitamin E/kg IM for 7 days, showed a marked reduction in functional factor II activity, but normal factor II levels using Echis venom on coagulation analysis. In 12 humans receiving warfarin, vitamin E was administered in doses of 100 or 400 units/day orally for 4 wk. The results in these patients showed no significant change in the prothrombin time, factor II coagulant activity, or factor II antigen (by electroimmunoassay). However, by using a ratio of factor II coagulant activity to immunoreactive protein, significant reduction was observed when compared to pretreatment ratios. These data suggest that vitamin E acts at the step mediated by vitamin K and not in the synthesis of the factor II precursor. Although the administration of high doses of vitamin E in animals, and possibly humans, with vitamin K deficiency potentiates the vitamin K deficiency, this effect is not clinically obvious with 400 IU/day or less.

Topics: Adult; Animals; Blood Coagulation; Humans; Male; Prothrombin; Rats; Vitamin E; Vitamin K Deficiency; Warfarin

We present the case of an adult man with cardiofaciocutaneous syndrome, who initially presented to the emergency department with severe abdominal pain and distension, but was diagnosed with cardiac tamponade on CT after distended neck veins and tachycardia were identified on examination. He had emergency pericardial drainage to relieve the haemopericardium and was treated with colchicine. He was further found to be deficient in factors II, VII and X despite not being on warfarin, and was therefore supplemented with vitamin K. This confirms a diagnosis of vitamin K deficiency, likely multifactorial from malabsorption due to chronic intestinal pseudo-obstruction, small bowel obstruction and possibly exacerbated by subsequent ciprofloxacin use for small intestine bacterial overgrowth. This is the first report of spontaneous haemopericardium secondary to vitamin K deficiency in an adult patient not on anticoagulation, and is an important learning point due to the life-threatening progression of the haemopericardium and cardiac tamponade.

Topics: Adult; Cardiac Tamponade; Humans; Male; Pericardial Effusion; Vitamin K Deficiency; Warfarin

Vitamin K deficiency is known to cause impaired coagulation. We report a case of marked prolongation of the prothrombin time-international normalized ratio (PT-INR) associated with warfarin and vitamin K deficiency caused by endoscopic nasobiliary drainage (ENBD).. Oral administration of warfarin was initiated in a 67-year-old man after left hemihepatectomy. He developed a biliary fistula after surgery that was treated by ENBD, which resulted in significant prolongation of the PT-INR.. The effect of warfarin was enhanced in this patient due to reduced absorption of vitamin K as a result of external biliary drainage.

Topics: Aged; Biliary Fistula; Drainage; Drug Interactions; Endoscopy; Hepatectomy; Humans; International Normalized Ratio; Male; Prothrombin Time; Vitamin K Deficiency; Warfarin

Vitamin K (VK) is a co-factor in the post-translational gamma glutamic carboxylation of Gla-proteins. VK-dependent coagulation factors are carboxylated in the liver by VK1. Osteocalcin and Matrix-Gla protein (MGP) are carboxylated in extrahepatic tissues by VK2. A model of VK deficiency would be suitable for studying extrahepatic Gla-proteins provided that severe bleeding is prevented.. The aim of this work was to adapt an established protocol of vascular calcification by warfarin-induced inactivation of MGP as a calcification inhibitor, in an attempt to create a broader state of subclinical VK deficiency and to verify its safety.. Two consecutive experiments, each lasting 4 weeks, were required to modify the dosing schedule of warfa-rin and VK1 and to adapt it to the Wistar rats used. The original high doses of warfarin used initially had to be halved and the protective dose of VK1 to be doubled, in order to avoid treatment-induced hemorrhagic deaths. The second experiment aimed to confirm the efficacy and safety of the modified doses. To verify the VK deficiency, blood vessels were examined histologically for calcium deposits and serum osteocalcin levels were mea-sured.. The original dosing schedule induced VK deficiency, manifested by arterial calcifications and dramatic changes in carboxyl-ated and uncarboxylated osteocalcin. The modified dosing regimen caused similar vascular calcification and no bleeding.. The modified protocol of carefully balanced warfarin and VK1 doses is an effective and safe way to induce subclinical VK deficiency that can be implemented to investigate VK-dependent proteins like osteocalcin.

Topics: Animals; Anticoagulants; Antifibrinolytic Agents; Arteries; Asymptomatic Diseases; Calcium-Binding Proteins; Carbon-Carbon Ligases; Disease Models, Animal; Extracellular Matrix Proteins; Matrix Gla Protein; Osteocalcin; Rats; Vascular Calcification; Vitamin K 1; Vitamin K 2; Vitamin K Deficiency; Warfarin

Vitamin K is present in the testes though its actual function in male reproduction is poorly understood. This study investigated the harmful effect of extrahepatic vitamin K insufficiency on the testicular structure. Sprague-Dawley rats were fed with a diet containing warfarin for 2, 4 and 8 weeks; control animals received a standard diet without warfarin. It was found that extrahepatic vitamin K deficiency that is induced by warfarin results in histopathological features that range from delayed spermiation, presence of multinucleated giant cells in the seminiferous tubules, germ cells degeneration, asthenozoospermia, oligozoospermia and increase in the percentage of abnormal sperm morphology when compared to the controls. Data obtained from the two groups were analysed using the Student t test. It is concluded that warfarin-induced vitamin K deficiency has a negative impact on spermatogenesis.

Topics: Administration, Oral; Animals; Disease Models, Animal; Humans; Infertility, Male; Male; Rats; Rats, Sprague-Dawley; Seminiferous Tubules; Spermatogenesis; Spermatozoa; Vitamin K; Vitamin K Deficiency; Warfarin

Vitamin K is a vital component within both the intrinsic and extrinsic coagulation cascade as certain factors (II, VII, IX, X and protein C and S) utilize vitamin K as a cofactor during post translational modification. Deficiency of vitamin K can result in the inability to properly form blood clots, both in vivo and in vitro, due to reduced vitamin K dependent factor levels and function. Vitamin K deficiency can result from congenital causes, such as VKOR or CYP2C9 mutations, or acquired causes, such as nutritional deficiencies, antibiotic therapy, or supra-therapeutic warfarin dosing.. In this case we present a patient with multifactorial vitamin K deficiency (due to nutritional defects and multiple genetic mutations in VKOR and CYP2C9) that was exacerbated by antibiotic and warfarin therapy during her hospital admission.. This case displays the importance of genetic testing prior to warfarin dosing and the role antibiotics play in the coagulation cascade.

Topics: Aged; Anti-Bacterial Agents; Anticoagulants; Automation, Laboratory; Blood Coagulation; Female; Humans; Thrombosis; Vitamin K Deficiency; Warfarin

Vitamin K intake is considered as a controllable contributor to warfarin sensitivity. It is restricted in warfarin-treated patients. However, little study has assessed the vitamin K status in warfarin-treated patients. We directly measured plasma vitamin K in warfarin-treated patients and evaluated its effect on anticoagulation.. A total of 302 plasma vitamin K concentrations were assessed using high-performance liquid chromatography for 203 outpatients with atrial fibrillation under warfarin treatment. Clinical and laboratory information including warfarin dosage, plasma warfarin concentrations, prothrombin time international normalized ratio (PT INR) and CYP2C9/VKORC1 genotypes was reviewed retrospectively. The anticoagulation stability (intra-individual variability, frequency of PT INR tests and complications) was investigated in 163 patients with long-term warfarin therapy. Plasma vitamin K was measured in 40 healthy subjects and in 40 patients before and after initial warfarin treatment.. Vitamin K concentrations were significantly decreased after the initiation of warfarin treatment (before treatment: 1.72 ng/ml; after treatment: 0.59 ng/ml, P<0.05). There was a large inter-individual variability in vitamin K levels (0.2-4.2 ng/ml) in warfarin-treated patients. PT INR was more frequently checked in patients with low plasma vitamin K levels than in those with high vitamin K levels (9.5 times/year vs 7.5 times/year, P=0.029). Two patients with gross hematuria showed very low vitamin K levels (<0.4 ng/ml).. We found high inter- and intra-individual variability in vitamin K concentration in warfarin-treated patients. Low vitamin K concentration in warfarin-treated patients suggested excessive dietary restriction. Plasma vitamin K measurement would be helpful for dietary control and anticoagulation stability.

Topics: Adult; Aged; Aged, 80 and over; Anticoagulants; Atrial Fibrillation; Diet; Drug Monitoring; Enzyme Inhibitors; Female; Food-Drug Interactions; Hematuria; Humans; International Normalized Ratio; Male; Middle Aged; Nutritional Status; Republic of Korea; Retrospective Studies; Vitamin K; Vitamin K Deficiency; Vitamin K Epoxide Reductases; Warfarin

We report a case of absolute vitamin K deficiency (VKD) diagnosed by measuring serum VK levels in an elderly woman undergoing warfarin therapy. A 78-year-old woman was admitted to our hospital because of dyspnea and sore throat diagnosed as pharyngitis 1 week before admission. On admission, the sore throat had exacerbated and dyspnea developed. She had history of atrial fibrillation, for which warfarin 1.5 mg/d was started approximately 10 years prior and her international normalized ratio (INR) had been maintained at an acceptable therapeutic level. Blood results revealed unmeasurable INR and abnormally prolonged activated partial thromboplastin time (APTT). She was diagnosed with adenoiditis and warfarin-related coagulopathy and administered intravenous VK (20 mg) and fresh frozen plasma (FFP; 4 U), which improved INR and APTT. Since the coagulopathy responded to intravenous VK administration, the patient was clinically diagnosed with warfarin-related relative VKD. Approximately 1 month later, she returned with complaints of sore throat. Blood results indicated abnormal INR (7.22) and APTT (N80.0 s). She was diagnosed with recurrent adenoiditis and VK deficient coagulopathy. The patient’s serum VK levels were low (VK1 level, 0.13 ng/mL; VK2 levels, 0.85 ng/mL). Initial treatment of VK (20 mg) and FFP followed by intravenous VK (20 mg/d) for 6 days, her symptoms dissipated. Warfarin was suspected to have caused absolute VKD. Severe coagulopathy in patients undergoing warfarin therapy is primarily caused by, relative VKD. However, the possibility of warfarin-related absolute VKD should be suspected when INRis not sufficiently improved by intravenous VK administration.

Topics: Aged; Anticoagulants; Atrial Fibrillation; Emergency Service, Hospital; Female; Humans; Vitamin K; Vitamin K Deficiency; Vitamins; Warfarin

Serum des-γ-carboxy prothrombin (DCP) levels using a newly developed electrochemiluminescence immunoassay (ECLIA, novel DCP [NX-DCP]) were measured, and the utility of NX-DCP and DCP/NX-DCP ratio for the diagnosis of hepatocellular carcinoma (HCC) was investigated. Antigenic differences in DCP between HCC and non-HCC patients were elucidated.. The subjects included 170 patients with HCC, 61 with benign liver disease, 12 with obstructive jaundice, and 10 warfarin users. NX-DCP was quantitated by sandwich ECLIA employing novel anti-DCP monoclonal antibodies, P11 and P16. Conventional DCP was quantitated by standard ECLIA. DCP extracted from serum by affinity-chromatography was analyzed by Western blotting.. Conventional serum DCP levels were high in patients with HCC and obstructive jaundice, and in warfarin users, consistent with previous reports. Serum NX-DCP levels were high only in warfarin users and obstructive jaundice patients (vitamin K-deficient patients) but not in HCC patients. The DCP/NX-DCP ratio was significantly higher in the HCC group than in the benign liver disease, obstructive jaundice, and warfarin groups (P < 0.001). Receiver operating characteristic analysis showed significant superiority of the DCP/NX-DCP ratio over conventional DCP as a marker for HCC diagnosis (P < 0.05). Western blot analysis showed that P11 and P16 reacted strongly with DCP from a warfarin user and an obstructive jaundice patient but very faintly with DCP from an HCC patient. Immunohistochemistry on HCC samples and autopsied normal liver tissues from warfarin users showed similar results.. The DCP/NX-DCP ratio is very useful for diagnosing HCC. DCP in HCC patients is distinct from that in vitamin K-deficient patients.

Topics: Adult; Aged; Aged, 80 and over; Biomarkers; Biomarkers, Tumor; Carcinoma, Hepatocellular; Diagnosis, Differential; Female; Humans; Immunoassay; Jaundice, Obstructive; Liver Neoplasms; Male; Middle Aged; Protein Precursors; Prothrombin; Vitamin K Deficiency; Warfarin

Coronary artery calcification is a recognised risk factor for ischaemic heart disease and mortality. Evidence is now strong that Mönckeberg's arteriosclerosis, a form of vascular calcification, can be attributable to vitamin K deficiency, but that vitamin K-2, especially the MK-4 form from foods like cheese can be protective. Warfarin blocks the recycling of hepatic and peripheral vitamin K leading to secondary vitamin K deficiency with adverse effects on vasculature, bone, kidneys, brain and other tissues and systems (inflammatory, immune function and neoplasia at least). There is individual susceptibility to vitamin K deficiency and warfarin sensitivity, partly explicable in terms of genetic polymorphisms, epigenetics, diet and pharmacotherapy. The emergence of extensive coronary calcification in a man with atrial fibrillation treated for a decade with warfarin is described by way of illustration and to raise the present clinical management conundrums. Finally, a putative set of recommendations is provided.

Topics: Calcinosis; Coronary Artery Disease; Diet; Factor Xa Inhibitors; Humans; Male; Middle Aged; Monckeberg Medial Calcific Sclerosis; Vitamin K 1; Vitamin K 2; Vitamin K Deficiency; Warfarin

Neonatal chondrodysplasia punctata (CDP) is characterized by epiphyseal stippling and midfacial hypoplasia. CDP is usually inherited, but can be acquired because of maternal vitamin K deficiency. We describe an infant with CDP born to a teenager with sickle cell anemia and transfusional iron overload. The mother had severe liver fibrosis, elevated liver iron concentration (34 mg Fe/g), and coagulopathy, but no gestational use of warfarin. Fetal abnormalities were attributed to vitamin K deficiency secondary to liver dysfunction from iron toxicity. Treatment of iron overload among women with sickle cell anemia of childbearing potential is important to avoid possible CDP in newborns.

Topics: Abnormalities, Drug-Induced; Adolescent; Anemia, Sickle Cell; Chondrodysplasia Punctata; Female; Humans; Infant, Newborn; Iron Overload; Liver Diseases; Male; Nasal Bone; Pregnancy; Pregnancy Complications; Transfusion Reaction; Vitamin K Deficiency; Warfarin

A 53 year old female who was maintained on long-term warfarin therapy due to history of pulmonary embolism, repeatedly presents with an abnormally prolonged Prothrombin Time (PT) and Activated Partial Thromboplastin Time (APTT). After many asymptomatic episodes were corrected with Vitamin K therapy to temporarily reverse the effects of the warfarin, the cause of the apparent coagulopathy was further investigated. Factor Activity Assays of the common pathway factors II, IX, and X all revealed critically low values; below the threshold even a loading dose of warfarin is typically capable of eliciting. The patient tested strongly positive for Tissue Transglutaminase IgA, which is highly suggestive of a gluten-sensitive enteropathy. One effect of this condition is malabsorption due to flattened intestinal villi. The patient was determined to have an acquired vitamin K deficiency secondary to gluten-sensitive enteropathy. Her condition was exacerbated by the long-term warfarin therapy, resulting in the prolonged PT and PTT. The patient was treated with vitamin K therapy, which reversed the deficiency and corrected her abnormal coagulation results.

Topics: Anticoagulants; Blood Coagulation; Blood Coagulation Disorders; Celiac Disease; Drug Hypersensitivity; Female; Humans; International Normalized Ratio; Middle Aged; Partial Thromboplastin Time; Prothrombin Time; Treatment Outcome; Vitamin K; Vitamin K Deficiency; Warfarin

Topics: Aged, 80 and over; Anticoagulants; Atrial Fibrillation; Blood Coagulation; Dietary Supplements; Drug Combinations; Drug Interactions; Female; Humans; International Normalized Ratio; Vitamin K Deficiency; Vitamins; Warfarin

Use of a coagulation panel [prothrombin time (PT), partial thromboplastin time (PTT), thrombin time (TT) and fibrinogen], intended for evaluation of bleeding, tripled over 6 years, out of proportion to admissions, surgery, or transfusions. To determine whether the panels were ordered appropriately, we classified 28,737 sets of panel results into groups followed by chart reviews to determine typical patient histories. In 39% of panels, PT/PTT was normal. Prolonged PT occurred in 33% of results, due to liver failure (8%), warfarin (23%), and presumed vitamin K deficiency (69%). Prolonged PTT occurred in 34% of results and was primarily associated with long PT or lupus inhibitors. Prolonged PTT and TT (15% of panels) indicated heparin therapy. Fibrinogen was normal in 98% and low in 1.4%. Critical fibrinogen (below 100 mg/dl, 0.6% of panels) was associated with bleeding in 90% of patients. Only 8% of panel orders were clinically indicated based on patient history. Clinician interviews indicated many were unaware the panel included fibrinogen and TT. Interventions included an education program and an order form change. The education program had no effect on overall order volume or test selection. A later order form change made TT and fibrinogen a separate order. This reduced TT and fibrinogen testing by 90% without complaints or changes in blood transfusion statistics. We conclude that many coagulation test panel orders were not clinically indicated, that PT more often diagnosed vitamin K deficiency than bleeding risk, and that order-based restriction of testing was more effective than educational programs at introducing change in clinical test utilization.

Topics: Anticoagulants; Biomarkers; Blood Coagulation; Blood Coagulation Disorders; Fibrinogen; Hemorrhage; Humans; Partial Thromboplastin Time; Prothrombin Time; Risk Factors; Thrombin Time; Vitamin K Deficiency; Warfarin

There is a lack of guidelines regarding the selection of patients who need intravenous heparin, duration of intravenous heparin, and future use of warfarin in prevention and treatment of warfarin-induced skin necrosis. This case report emphasizes the challenges in dealing with vitamin K antagonists (VKA) therapy.

Topics: Aged; Anticoagulants; Combined Modality Therapy; Drug Administration Schedule; Heparin; Humans; Male; Necrosis; Skin; Systemic Inflammatory Response Syndrome; Thrombophilia; Vitamin K Deficiency; Warfarin

Topics: Alzheimer Disease; Anticoagulants; Atrial Fibrillation; Dementia, Vascular; Humans; Incidence; Risk Factors; Vitamin K Deficiency; Warfarin

Topics: Aged; Anticoagulants; Brassica; Diet; Dyspnea; Female; Food-Drug Interactions; Hemorrhage; Humans; International Normalized Ratio; Pulmonary Embolism; Recurrence; Vitamin K Deficiency; Warfarin

Vitamin K (K) inadequacy may cause bone loss. Thus, K deficiency induced by anticoagulants (e.g., warfarin) may be an osteoporosis risk factor. The skeletal impact of long-term warfarin anticoagulation was evaluated in male monkeys. No effect on BMD or bone markers of skeletal turnover was observed. This study suggests that warfarin-induced K deficiency does not have skeletal effects.. The skeletal role of vitamin K (K) remains unclear. It is reasonable that a potential role of vitamin K in bone health could be elucidated by study of patients receiving oral anticoagulants that act to produce vitamin K deficiency. However, some, but not all, reports find K deficiency induced by warfarin (W) anticoagulation to be associated with low bone mass. Additionally, epidemiologic studies have found W use to be associated with either increased or no change in fracture risk. Such divergent results may imply that human studies are compromised by the physical illnesses for which W was prescribed.. To remove this potential confounder, we prospectively assessed skeletal status during long-term W anticoagulation of healthy nonhuman primates. Twenty adult (age, 7.4-17.9 yr, mean, 11.7 yr) male rhesus monkeys (Macaca mulatta) were randomized to daily W treatment or control groups. Bone mass of the total body, lumbar spine, and distal and central radius was determined by DXA at baseline and after 3, 6, 9, 12, 18, 24, and 30 mo of W treatment. Serum chemistries, urinary calcium excretion, bone-specific alkaline phosphatase, and total and percent unbound osteocalcin were measured at the same time-points. Prothrombin time and international normalized ratio (INR) were monitored monthly. Serum 25-hydroxyvitamin D was measured at the time of study conclusion.. W treatment produced skeletal K deficiency documented by elevation of circulating undercarboxylated osteocalcin (8.3% W versus 0.4% control, p<0.0001) but did not alter serum markers of skeletal turnover, urinary calcium excretion, or BMD.. In male rhesus monkeys, long-term W anticoagulation does not alter serum markers of bone turnover or BMD. Long-term W therapy does not have adverse skeletal consequences in primates with high intakes of calcium and vitamin D.

Topics: Animals; Anticoagulants; Biomarkers; Bone Density; Bone Resorption; Calcium; Fractures, Bone; Lumbar Vertebrae; Macaca mulatta; Male; Radius; Risk Factors; Time Factors; Vitamin D; Vitamin K Deficiency; Warfarin

Human coagulation factor VII (FVII) has two N-glycosylation sites (N145 and N322) and two O-glycosylation sites (S52 and S60). In transiently transfected COS-7 cells, all combinations of N- and O-glycosylation knock-out mutations reduced the release of FVII to the medium. Pulse-chase analysis of CHO-K1 cell lines expressing recombinant FVII demonstrated that virtually all wild-type FVII synthesized was secreted from the cells, whereas both N- and O-glycosylation knock-out mutations induced partial intracellular degradation of the synthesized FVII. Likewise, two thirds of the FVII synthesized in vitamin K-depleted and warfarin-treated CHO cells was degraded intracellularly, demonstrating the importance of gamma-carboxylation for the secretion of FVII. The furin inhibitor decanoyl-R-V-K-R-chloromethylketone inhibited propeptide cleavage, but FVII with propeptide appeared to be secreted equally well as FVII without propeptide. Propeptide cleavage was not inhibited by vitamin K depletion and warfarin treatment, suggesting that for FVII, correct gamma-carboxylation is not required for optimal processing of the propeptide. In conclusion, all post-translational modifications of FVII except propeptide cleavage were important for complete secretion of the synthesized FVII and to avoid intracellular degradation. Thus, the extensive post-translational modification of FVII seems critical for the intracellular stability of the protein and is required for keeping the protein in the secretory pathway.

Topics: Animals; CHO Cells; Cricetinae; Cricetulus; Factor VII; Glycosylation; Humans; Mutation; Protein Processing, Post-Translational; Vitamin K Deficiency; Warfarin

Alterations in vitamin K availability can significantly influence anticoagulation response to warfarin. Apolipoprotein E (APOE) plays a part in the hepatic uptake of lipid-soluble vitamin K. This study aimed to determine the influence of common polymorphisms in the APOE gene on warfarin dose requirements. patients with stable anticoagulation control and with a target International Normalized Ratio (INR) 2.0-3.0 were genotyped for the APOE epsilon2, epsilon3 and epsilon4 variants. Mean +/- SD daily warfarin doses were significantly lower in patients carrying at least one epsilon4 allele compared to the epsilon3epsilon3 reference genotype (3.3 +/- 1.9 versus 4.0 +/- 1.8; P = 0.03; 95% CI: 0.1-1.2). Multivariate regression analysis showed that patient age, height and CYP2C9, VKORC1 and APOE genotypes significantly contributed to warfarin dose requirement (R = 57%). only the epsilon4 allele of APOE was found to make a significant (P = 0.002) but small contribution to warfarin dose requirement. There was no significant difference in fasted plasma vitamin K concentration between patients with the different APOE genotypes. This study suggests that APOE genotype is unlikely to have a clinically significant effect on warfarin dose requirements.

Topics: Adult; Aged; Aged, 80 and over; Anticoagulants; Apolipoproteins E; Blood Coagulation Disorders; Dose-Response Relationship, Drug; Drug Administration Schedule; Female; Humans; Male; Middle Aged; Polymorphism, Genetic; Vitamin K Deficiency; Warfarin

Topics: Anticoagulants; Arthritis, Juvenile; Child; Diagnosis, Differential; Epistaxis; Female; Hematuria; Humans; Infant; Kidney; Low Back Pain; Male; Prognosis; Urinalysis; Vitamin K Deficiency; Warfarin

Resistance to warfarin has been connected to an increase in dietary requirement for vitamin K in British strains of the Norway rat, Rattus norvegicus (Berk). This study examines vitamin K requirement of Danish anticoagulant-resistant Norway rats using a vitamin K deficient feeding test. Wild bromadiolone-resistant rats sampled from different localities in Denmark and rats from bromadiolone-resistant and susceptible laboratory strains were fed on a vitamin K deficient diet over a maximum period of 15 days. Development of vitamin K deficiency, measured as reduced blood-clotting capacity, took place in 43% of the Danish resistant rats and was independent of sex, treatment with supplementary vitamin K3 and sampling locality. Development of deficiency was slower for resistant rats that were supplemented with vitamin K3 prior to the feeding test, suggesting storage of the vitamin K in a vitamin body pool. Intraperitoneal administration of vitamin K1 revealed that 80 microg vitamin K1 kg(-1) bodyweight was sufficient to restore normal blood clotting activity in deficient rats, while 60 microg vitamin K1 kg(-1) bodyweight was insufficient. We conclude that vitamin K requirement is moderately increased in Danish homozygous resistant rats whereas heterozygous resistant rats only have a minor increase in vitamin K requirement compared with susceptible rats. We found no indication of different resistance types being present in our test material since vitamin K requirement was not different between rats from separate sampling localities.

Topics: 4-Hydroxycoumarins; Animals; Anticoagulants; Antifibrinolytic Agents; Blood Coagulation; Drug Resistance; Female; Male; Rats; Vitamin K; Vitamin K Deficiency; Warfarin

There is evidence from knock-out mice that the extrahepatic vitamin K-dependent protein, matrix gla protein, is necessary to prevent arterial calcification. The aim of this study was to determine if a warfarin treatment regimen in rats, designed to cause extra-hepatic vitamin K deficiency, would also cause arterial calcification. Sprague-Dawley rats were treated from birth for 5-12 weeks with daily doses of warfarin and concurrent vitamin K1. This treatment causes an extrahepatic vitamin K deficiency without affecting the vitamin K-dependent blood clotting factors. At the end of treatment the rats were killed and the vascular system was examined for evidence of calcification. All treated animals showed extensive arterial calcification. The cerebral arteries and the veins and capillaries did not appear to be affected. It is likely that humans on long-term warfarin treatment have extrahepatic vitamin K deficiency and hence they are potentially at increased risk of developing arterial calcification.

Topics: Animals; Arterial Occlusive Diseases; Calcinosis; Rats; Rats, Sprague-Dawley; Vitamin K Deficiency; Warfarin

To further characterize the skeletal role of vitamin K (K), markers of bone turnover, density, and strength were evaluated in rats with diet- or warfarin (W)-induced K insufficiency. One hundred two, 7-week-old, female rats were randomly assigned to low K (phylloquinone [K1], 20 microg/kg diet), control K (K1, 1300 microg/kg diet), low-dose W (W, 1.5 mg/kg control diet), or high-dose W plus K (W/K1, 10/100 mg/kg diet). Femur bone mineral content (BMC) and bone mineral density (BMD), plasma prothrombin time (PT) and prothrombin concentration (PC), and serum total alkaline phosphatase (ALP) and skeletal alkaline phosphatase (sALP) were measured at baseline and days 20, 40, 60, and 80. Serum total osteocalcin (OC) and undercarboxylated osteocalcin (ucOC) and femur length (FL) were measured at baseline and day 80. Left femur OC was measured and biomechanical testing of the right femur and third lumbar vertebral body was performed at day 80. Low dietary K elevated circulating ucOC (17% higher than control; p < 0.0001) at day 80. Furthermore, in both W groups, essentially all circulating OC was undercarboxylated and femur OC was lower than control (p < 0.0001). However, there was no change in femur percent ucOC, suggesting deposition of less newly synthesized OC. No between group differences were observed in PT, ALP, sALP, FL, BMC, BMD, or bone strength. In conclusion, skeletal K insufficiency can be induced by W or diet manipulation. This does not hinder peak bone mass attainment in female rats; however, W causes less newly synthesized OC to be deposited in bone.

Topics: Absorptiometry, Photon; Animals; Anticoagulants; Bone and Bones; Bone Density; Bone Development; Carboxylic Acids; Diet; Female; Osteocalcin; Rats; Vitamin K; Vitamin K Deficiency; Warfarin

Atrophic gastritis patients have intestinal bacterial overgrowth which could produce menaquinones. The aim of this study was to evaluate the interaction between a diet low in phylloquinone and minidoses of warfarin in subjects with and without bacterial overgrowth. Subjects with atrophic gastritis (indicated by serum pepsinogen ratio) and healthy volunteers were studied while fed a restrictive phylloquinone diet and while receiving a minidose of warfarin. Coagulation times, serum osteocalcin, serum undercarboxylated osteocalcin, plasma phylloquinone, plasma K-epoxide, plasma undercarboxylated prothrombin (PIVKA)-II and urinary gamma-carboxyglutamic acid (Gla) were measured. At baseline, there were no differences between groups for any variable measured. Comparisons between baseline and post intervention in both groups, showed significant increases in circulating levels of K-epoxide, PIVKA II and undercarboxylated osteocalcin. However, no differences were observed when comparisons were made between groups. Our data do not support the hypothesis that bacterial synthesis of menaquinones in patients with bacterial overgrowth due to atrophic gastritis confers considerable resistance to the effect of warfarin.

Topics: Aged; Anticoagulants; Bacteria, Anaerobic; Diet; Female; Food-Drug Interactions; Gastritis, Atrophic; Humans; Hydrogen-Ion Concentration; Intestines; Male; Middle Aged; Vitamin K; Vitamin K 1; Vitamin K Deficiency; Warfarin

Because of the emergence of warfarin resistance in rodents, second-generation anticoagulants named "superwarfarins" were developed and marketed in over-the-counter rodenticide products. The availability of these compounds has resulted in accidental or intentional human ingestions, which cause severe bleeding. The methods for diagnosis and treatment of patients using superwarfarins are different from those for patients taking the regular warfarins. We report a case of intentional superwarfarin ingestion that caused petechiae and hematuria. Although the patient denied taking anticoagulant, the persistence of vitamin K-dependent factor deficiency led us to investigate the serum for anticoagulant rodenticides. We found high levels of brodifacoum, a superwarfarin compound. This case emphasizes the need for suspicion of superwarfarin poisoning in patients who show unexplained bleeding due to deficiency of vitamin K-dependent factors and resistance to treatment.

Topics: 4-Hydroxycoumarins; Adult; Blood Coagulation Tests; Hematuria; Humans; Male; Poisoning; Rodenticides; Vitamin K Deficiency; Warfarin

Racemic sodium warfarin, Coumadin, is widely used in the prevention of thromboembolic disease. The present study was undertaken to characterize three novel classes of warfarin analogs, and to compare them with the warfarin enantiomers. All three classes of compounds inhibit vitamin K epoxide reductase, the enzyme inhibited by racemic warfarin. The alcohol and the ester analogs have reduced protein binding compared with R-(+)-warfarin. The ester and the fluoro-derivatives have similar in vivo anticoagulant activity in the rat to that of S-(-)-warfarin. Thus, it is possible to synthesize novel warfarin analogs that differ from racemic warfarin or its enantiomers in certain selected properties.

Topics: Animals; Anticoagulants; Humans; Male; Microsomes, Liver; Mixed Function Oxygenases; Rats; Rats, Sprague-Dawley; Stereoisomerism; Structure-Activity Relationship; Vitamin K; Vitamin K Deficiency; Vitamin K Epoxide Reductases; Warfarin

Three unrelated infants presented with radiographic punctate calcifications, nasal hypoplasia, and abnormalities of the spine. Additional anomalies included cupped ears in 2 patients and one each with Dandy-Walker malformation with hydrocephaly, congenital cataracts, and peripheral pulmonary artery stenosis. The mothers of these 3 patients had chronic conditions associated with intestinal malabsorption requiring total parenteral nutrition for varying periods of time. The underlying causes of malabsorption were celiac disease, short bowel syndrome secondary to surgical resection, and jejuno-ileal bypass, respectively. Bleeding diathesis occurred in one mother requiring vitamin K supplementation during the second and third trimesters of pregnancy. We speculate that the chondrodysplasia punctata and other abnormalities in these children were caused by an acquired maternal vitamin K deficiency manifested during early pregnancy. However, the involvement of other vitamin deficiencies cannot be excluded. Thus, vitamin K deficiency of the embryo secondary to maternal malabsorption appears to be a third vitamin K-related mechanism leading to chondrodysplasia punctata in addition to warfarin embryopathy and epoxide reductase deficiency (pseudo-warfarin embryopathy).

Topics: Abnormalities, Drug-Induced; Anticoagulants; Child, Preschool; Chondrodysplasia Punctata; Female; Fetal Diseases; Humans; Infant; Infant, Newborn; Magnetic Resonance Imaging; Malabsorption Syndromes; Pregnancy; Pregnancy Complications; Radiography; Vitamin K; Vitamin K Deficiency; Warfarin

To clarify the origin of organ menaquinone-4 (MK-4), the distributions of phylloquinone and MK-4 were investigated in rats fed diets containing phylloquinone, MK-4 or menadione (1.1, 2.2 and 31 mumol/kg diet, respectively, 6 rats per group). Warfarin (2 x 1 mg/kg subcutaneously) was given (3 rats per group) to study the effect of vitamin K cycle blockage. In rats fed phylloquinone the vitamin accumulated mainly in liver and heart. Additionally, the diet resulted in significantly higher organ MK-4 concentrations compared with the vitamin K-deficient controls. The epoxide of MK-4 also was significantly higher in some organs. The MK-4 diet increased MK-4 concentration primarily in the heart, liver and lung. Rats fed menadione had significantly higher MK-4 and MK-4 epoxide concentrations in all organs examined. The greatest accumulations were in nonhepatic organs, particularly the pancreas, salivary gland and brain. Generally, liver and plasma had low MK-4 concentrations. Warfarin treatment lowered significantly the MK-4 concentrations, whereas MK-4 epoxide accumulated. The study shows the following: 1) dietary phylloquinone is accumulated mainly in the heart and liver, 2) the MK-4 accumulation in nonhepatic organs is due to synthesis rather than uptake and 3) MK-4 rather than phylloquinone may be the functional vitamin in nonhepatic organs.

Topics: Animals; Brain Chemistry; Liver; Lung; Male; Myocardium; Pancreas; Rats; Rats, Wistar; Salivary Glands; Vitamin K; Vitamin K 1; Vitamin K Deficiency; Warfarin

A cDNA encoding vitamin K-dependent gamma-glutamyl carboxylase was cloned from a human Hep G2 cDNA library. The RNA transcript of the enzyme was found to be widely distributed in various human and rat tissues with liver showing the highest level. The carboxylase transcription in liver was not affected in rats treated with a single dose of warfarin (10 mg/kg) when measured up to 48 hours after the dose, though, at 12 hours, carboxylase activity measured in liver microsomes was elevated 5.4 fold over controls (p < 0.001). In rats fasted for 72 hours there was no affect on transcription in the liver while hepatic carboxylase activity increased 4.1 fold (p < 0.001). These data suggest that the increase in activity of the liver carboxylase in warfarin treated or fasted rats was not regulated by transcription but more likely was due to a posttranscriptional mechanism.

Topics: Actins; Animals; Blotting, Northern; Carbon-Carbon Ligases; Cell Line; Chlorocebus aethiops; Cloning, Molecular; Fasting; Gene Library; Humans; Kinetics; Ligases; Microsomes, Liver; Rats; Rats, Sprague-Dawley; Recombinant Proteins; RNA, Messenger; Time Factors; Transcription, Genetic; Transfection; Tumor Cells, Cultured; Vitamin K Deficiency; Warfarin

This report describes a patient who had significant postoperative bleeding 4 days after undergoing surgery while using a tranexamic acid (4.8%) mouth rinse protocol for local control of hemostatis. Patients undergoing dentoalveolar surgery who are receiving chronic oral anticoagulants are treated with a tranexamic acid mouth rinse at our hospital. No systemic modification of their coagulation status is attempted. The postoperative bleeding problem that developed was determined to be caused by an antibiotic-induced vitamin K deficiency rather than a failure of the tranexamic acid protocol.

Topics: Aged; Amoxicillin; Anticoagulants; Antifibrinolytic Agents; Dental Care for Chronically Ill; Drug Interactions; Heart Valve Prosthesis; Humans; Male; Penicillins; Postoperative Hemorrhage; Tooth Extraction; Tranexamic Acid; Vitamin K Deficiency; Warfarin

We developed a RIA involving a polyclonal antibody against bovine osteocalcin, which has a carboxy-terminal epitope. Although the antibody recognizes both native and descarboxy osteocalcin, the two forms of osteocalcin were differentiated by adsorption to barium sulfate, taking advantage of the calcium-binding properties of the vitamin K-dependent gla domain. To test the clinical application of undercarboxylated osteocalcin, we examined the effect of minidose warfarin on this measure in nine healthy subjects, ages 60 to 80 years. The percentage of undercarboxylated osteocalcin increased by 170% +/- 36% (mean +/- SE) after 7 days of treatment with warfarin, 1 mg/day. The effectiveness of undercarboxylated osteocalcin as a sensitive measure of vitamin K nutritional status was further established when concentrations dropped to 17% +/- 14% below baseline with 2 days of repletion with vitamin K1, 5 mg/day, during which prothrombin times did not leave the normal range.

Topics: Adsorption; Aged; Barium Sulfate; Female; Humans; Male; Middle Aged; Nutritional Status; Osteocalcin; Vitamin K; Vitamin K Deficiency; Warfarin

Topics: Anticoagulants; Blood Loss, Surgical; Cardiopulmonary Bypass; Humans; Plasma; Preanesthetic Medication; Vitamin K 1; Vitamin K Deficiency; Warfarin

After optimizing conditions for maximal production of menaquinones (MK), S. aureus and B. vulgatus were grown in batches, harvested and extracted for qualitative and quantitative MK content utilizing HPLC (high performance liquid chromatography) until a total of 6 mg was available. Five normal healthy male volunteers were placed on a vitamin K1 deficient diet (< or = 25 micrograms/day) and were subsequently warfarinized to maintain a prothrombin time (PT) 1.5-2 times control. Following stabilization of daily warfarin dosage 1 mg doses of the extracted MK were orally administered. As a control, the same volunteers were later warfarinized but no MK was given. Within 24 h of MK administration the prothrombin time (PT) decreased (mean +/- SEM) 3.6 +/- 1.0 s (p < 0.005) and the Factor VII level increased 0.36 +/- 0.3 u/ml (p < 0.005) vs a PT increase of 1.0 +/- 1.0 s (p > 0.1) and a Factor VII level increase of 0.03 +/- 0.1 u/ml (p > 0.1) in the control phase. Within 48 h of MK administration the PT was normal in all subjects but remained > or = 1.5 times control in the control phase. These data demonstrate for the first time the absorption and bioactivity of bacterially synthesized vitamin K in humans.

Topics: Administration, Oral; Adult; Bacteroides; Factor VII; Humans; Intestinal Absorption; Male; Prothrombin; Prothrombin Time; Staphylococcus aureus; Vitamin K; Vitamin K 1; Vitamin K Deficiency; Warfarin

Sprague-Dawley rats were given daily subcutaneous doses of sodium warfarin (100 mg/kg) and vitamin K1 (10 mg/kg) for up to 12 weeks, starting on the day after birth. This dosing regimen creates an extrahepatic vitamin K deficiency while preserving the vitamin K-dependent processes of the liver. Control rats received either vitamin K1 only or were untreated. All rats survived without any signs of hemorrhage. The warfarin-treated rats developed a marked maxillonasal hypoplasia associated with a 11-13% reduction in the length of the nasal bones compared with controls. The length of the posterior part of the skull was not significantly different from controls. In the warfarin-treated rats, the septal cartilage of the nasal septum showed large areas of calcification, not present in controls, and abnormal calcium bridges in the epiphyseal cartilages of the vertebrae and long bones. The ectopic calcification in the septal cartilage may have been the cause of the reduced longitudinal growth of the nasal septum and the associated maxillonasal hypoplasia. It is proposed that (1) the facial features of the human warfarin embryopathy are caused by reduced growth of the embryonic nasal septum, and (2) the septal growth retardation occurs because the warfarin-induced extrahepatic vitamin K deficiency prevents the normal formation of the vitamin K-dependent matrix gla protein in the embryo.

Topics: Animals; Animals, Newborn; Calcinosis; Cartilage Diseases; Female; Growth Plate; Male; Maxilla; Models, Biological; Nasal Bone; Nasal Septum; Rats; Rats, Sprague-Dawley; Skull; Species Specificity; Vitamin K 1; Vitamin K Deficiency; Warfarin

There is evidence that vitamin K-deficiency during human pregnancy can be caused by the therapeutic use of warfarin or phenytoin. The pregnancy histories of three cases of Binder's syndrome are reported. One was associated with warfarin exposure, one with phenytoin exposure and one with alcohol abuse. It is proposed that Binder's syndrome can be caused by prenatal exposure to agents that cause vitamin K-deficiency. Sprague-Dawley rats were treated from postnatal day 1 to 12 weeks with daily doses of warfarin (100 mg/kg) and concurrent vitamin K1 (10 mg/kg). This regimen creates a net extra-hepatic vitamin K-deficiency. The treated rats developed with a distinct facial appearance characterized by a markedly reduced snout. Histological examination showed that the normally non-calcified septal cartilage was extensively calcified. It is proposed that normal growth of the septal cartilage is necessary for the development of the profile of the nose and midface and that normal growth will only take place while the septal cartilage is uncalcified.

Topics: Adolescent; Alcoholism; Aneurysm, Ruptured; Animals; Cartilage; Child, Preschool; Female; Humans; Infant; Intracranial Aneurysm; Male; Maxilla; Nasal Bone; Nasal Septum; Phenytoin; Pregnancy; Pregnancy Complications, Cardiovascular; Prenatal Exposure Delayed Effects; Rats; Rats, Sprague-Dawley; Thrombophlebitis; Vitamin K; Vitamin K Deficiency; Warfarin

The cause of a fatal condition characterized by hemorrhagic cardiomyopathy, hemothorax, and coagulation defects in hysterectomy-derived male mice was investigated. Microscopic heart alterations included multifocal hemorrhage and necrosis with variable degrees of acute inflammation and fibroplasia that were most severe in the region of the atrioventricular junction. A spontaneous outbreak was arrested by increasing menadione Na-bisulfite (vitamin K) in the feed to 20 ppm. The complete syndrome including hemorrhagic cardiomyopathy was readily reproduced in germ-free male mice given a vitamin K-free diet, and in conventional male and female mice given Warfarin in the diet. We concluded that the cause of this condition was vitamin K deficiency.

Topics: Animals; Blood Coagulation Disorders; Cardiomyopathies; Female; Hemorrhagic Disorders; Hemothorax; Male; Mice; Mice, Inbred C3H; Mice, Inbred C57BL; Mice, Inbred CBA; Myocardium; Vitamin K; Vitamin K Deficiency; Warfarin

Skin necrosis is a well-known yet rare complication of oral anticoagulant therapy. We report the unusual recurrence of lesions typical of warfarin skin necrosis in the absence of anticoagulant therapy. A 59-year-old woman developed skin necrosis while receiving prophylactic warfarin following the detection of a large left ventricular thrombus. The warfarin was discontinued and the lesions improved. One month later new areas of skin necrosis developed although the patient had received no further warfarin. Progressive congestive heart failure, poor nutrition, and prolonged oral antibiotic therapy preceded the recurrence. Vitamin K deficiency was present on admission. The potential role of vitamin K-dependent coagulation factors in the pathogenesis of anticoagulant-associated skin necrosis is discussed.

Topics: Female; Humans; Middle Aged; Necrosis; Skin Diseases; Vitamin K Deficiency; Warfarin

Anticoagulation instability due to a change in intake of vitamin K after dietary modification was observed in 2 patients on long-term oral anticoagulants. One patient developed diffuse bruises treated conservatively with fresh frozen plasma transfusion and the other had a thrombosed aortic prosthesis which required emergency operation. To prevent such complications, dietary modification especially with food rich in vitamin K should be undertaken with care in patients on long-term oral anticoagulants.

Topics: Adult; Aortic Valve; Blood Coagulation; Diet; Drug Interactions; Female; Heart Valve Prosthesis; Humans; Male; Middle Aged; Skin Diseases; Thrombosis; Vitamin K; Vitamin K Deficiency; Warfarin

The modulation of phosphosphingolipid synthesis by vitamin K depletion has been observed in the vitamin K-dependent microorganism, Bacteriodes levii. When cultured briefly without the vitamin, a reduction occurred in the activity of the first enzyme of the sphingolipid pathway, 3-ketodihydrosphingosine synthase. In this report, 16-day-old mice were treated with the vitamin K antagonist, warfarin. Brain microsomes from these animals showed a 19% reduction in synthase activity. Mice treated with warfarin for 2 weeks showed a major reduction in sulfatide level (42%), with a lesser degree or no reduction in levels of gangliosides and cerebrosides. In further experiments, mice were treated with warfarin for 2 weeks and a group was then injected with vitamin K1 (aquamephyton) for 3 days. Enzyme activity returned to a normal level within 2-3 days. Sulfatide levels had increased 33% in the vitamin K-injected group and ganglioside levels also increased, where levels of cerebrosides and sphingomyelin declined. Sulfatide synthesis determined by [35S] sulfate incorporation, showed a 52% increase in incorporation following administration of vitamin K for 3 days. These results suggest a role for vitamin K in the biosynthesis of sulfatides and other sphingolipids in brain. This putative role could be by post-translational protein modification analogous to the role of vitamin K in other systems.

Topics: Animals; Brain; Glycosphingolipids; Mice; Mice, Inbred ICR; Oxo-Acid-Lyases; Phospholipids; Sphingolipids; Sulfoglycosphingolipids; Vitamin K; Vitamin K Deficiency; Warfarin

We have evaluated a boy who had excessive bleeding and bruising from birth and showed markedly prolonged prothrombin times, partially correctable by oral vitamin K administration. Additional laboratory studies demonstrated decreased activities of plasma factors II, VII, IX, and X; near normal levels of immunologically detected and calcium binding-independent prothrombin; undercarboxylation of prothrombin; excess circulating vitamin K epoxide; decreased excretion of carboxylated glutamic acid residues; and abnormal circulating osteocalcin. These results all are consistent with effects resulting from decreased posttranslational carboxylation secondary to an inborn deficiency of vitamin K epoxide reductase. This individual also had nasal hypoplasia, distal digital hypoplasia, and epiphyseal stippling on infant radiographs, all of which are virtually identical to features seen secondary to first-trimester exposure to coumarin derivatives. Therefore, by inference, the warfarin embryopathy is probably secondary to warfarin's primary pharmacologic effect (interference with vitamin K-dependent posttranslational carboxylation of glutamyl residues of various proteins) and may result from undercarboxylation of osteocalcin or other vitamin K-dependent bone proteins.

Topics: 1-Carboxyglutamic Acid; Abnormalities, Drug-Induced; Calcium-Binding Proteins; Child; Chromatography, High Pressure Liquid; Female; Fetal Diseases; Fingers; Humans; Male; Nose; Osteocalcin; Phenotype; Pregnancy; Prothrombin; Radiography; Vitamin K; Vitamin K 1; Vitamin K Deficiency; Warfarin

Mouse Lewis lung (LL) carcinoma cells possess a factor X activator (procoagulant) that is inhibited in vivo by warfarin treatment or diet-induced vitamin K deficiency. This inhibition suggests that vitamin-K-dependent proteins are involved in LL cell activation of factor X. A LL primary tumor clone (LL13) was isolated which contained a warfarin-sensitive vitamin-K cycle of metabolism and expressed factor X procoagulant activity. LL13 cells exposed to media containing warfarin or deficient in vitamin K grew as well as cells in normal media, and activated factor X to similar extents. In contrast, administration of warfarin to mice bearing LL13 cells inhibited factor X procoagulant activity as well as the vitamin K cycle of metabolism in the primary tumors. In relation to LL13 cells grown in media containing fetal bovine serum, those incubated for 20 hr in media containing mouse serum or the sera from LL13-bearing mice exhibited 9- to 10-times higher levels of factor X procoagulant activity. However, LL13 cells exposed to media containing the sera of warfarin-treated LL-13-bearing mice or to barium-sulfate-adsorbed normal mouse serum activated factor X much less efficiently. Collectively, these data suggest that inhibition of vitamin K function in LL cells does not affect the extent of factor X activation and thus the intrinsic factor X procoagulant is not a vitamin-K-dependent protein. They further suggest that both a warfarin-sensitive (vitamin-K-dependent) protein present in normal mouse serum and a LL13 cell component participate in factor X procoagulant activity.

Topics: Animals; Biotransformation; Blood Coagulation Factors; Cell Line; Culture Media; Factor X; Lung Neoplasms; Male; Mice; Mice, Inbred C57BL; Neoplasm Metastasis; Vitamin K; Vitamin K Deficiency; Warfarin

Descarboxyprothrombin (PIVKA II) is a precursor of prothrombin without biological activity, and it increases with vitamin K deficiency. We studied the time course changes in liver and plasma levels of PIVKA II during the progress of vitamin K deficiency in rats. Good correlation was observed between liver PIVKA II and plasma PIVKA II and between liver or plasma PIVKA II and plasma prothrombin in experiments in which rats were fed a vitamin K-deficient diet. Feeding of a vitamin K-deficient diet or fasting caused marked increases in liver and plasma PIVKA II in male rats and a weaker response in female rats. Warfarin, a vitamin K antagonist, caused an abrupt increase in liver PIVKA II, but the increase in plasma PIVKA II was delayed about 3 hr. Plasma prothrombin decreased from about 30 min later. Factor VII decreased similarly to prothrombin, and changes in the prothrombin time and activated partial thromboplastin time were slower than the changes in these substances. Sex differences were not seen in these warfarin actions. These observations indicate that liver and plasma PIVKA II are sensitive markers of vitamin K deficiency in rats, and assay of PIVKA II can be useful for analyzing the action mechanism of drugs which influence blood coagulation.

Topics: Animals; Barium; Barium Compounds; Biomarkers; Chlorides; Diet; Factor VII; Fasting; Female; Liver; Male; Microsomes, Liver; Partial Thromboplastin Time; Protein Precursors; Prothrombin; Rats; Rats, Inbred Strains; Sex Factors; Time Factors; Vitamin K Deficiency; Warfarin

This study reports an increased susceptibility to warfarin anticoagulation in mice bearing an experimental tumour, the Lewis lung carcinoma. In these animals, following a single i.v. injection of warfarin, the prothrombin complex activity decreased normally but recovered far slower than in controls, while the rate of degradation of the clotting factors was not modified. At the level of the vitamin K-dependent liver carboxylase, it was possible to demonstrate an increase in the endogenous substrate (reflecting an impairment of the carboxylase vitamin K dependent system). This abnormality was reversed by vitamin K administration and can be reasonably ascribed to a vitamin K deficiency in association with tumour growth.

Topics: Animals; Blood Coagulation; Carbon-Carbon Ligases; Ligases; Lung Neoplasms; Male; Mice; Mice, Inbred C57BL; Neoplasms, Experimental; Prothrombin; Vitamin K Deficiency; Warfarin

Vitamin K deficiency, either dietary or pharmacologically induced by warfarin, was unable to affect the metastatic capacity of cells from a benzopyrene-induced fibrosarcoma in C57BL/6J mice. The same cells had a procoagulant activity, of tissue thromboplastin type, which was also completely unaffected by vitamin K antagonism or deficiency. In another murine model of spontaneous metastasis we previously suggested that depression of a particular procoagulant such as a direct factor X activator might contribute to the antimetastatic activity of warfarin. The failure of vitamin K deficiency to affect both the procoagulant and the metastatic capacity of the model reported here offers strong negative support to the same concept.

Topics: Animals; Fibrosarcoma; Male; Mice; Mice, Inbred C57BL; Neoplasm Metastasis; Thromboplastin; Vitamin K Deficiency; Warfarin

Anecdotal observations of the behavior of rats with a vitamin K-deficiency suggested that this deficiency was associated with hypoactivity, general malaise, and a lack of exploratory behavior. These observations were pursued by assessing locomotor activity in a circular photocell-monitored track, open-field activity, and radial-arm maze performance in rats rendered vitamin K-deficient by dietary depletion or by warfarin treatment. There was a significant reduction (approximately 25% at the median) in the locomotor activity of dietary vitamin K-deficient rats compared with rats fed a control diet. In the open-field, warfarin administration was associated with a significant shift from more exploratory behaviors to less exploratory behaviors. Consistent with these findings, radial-arm maze assessment showed a comparative reduction in locomotor activity in the dietary vitamin K-deficient rats with no alteration in performance, i.e., short-term memory. These animal behavioral studies suggest that sub-clinical and clinical vitamin K-deficiency may contribute to physical and psychiatric symptomatology.

Topics: Animals; Behavior, Animal; Exploratory Behavior; Male; Memory, Short-Term; Motor Activity; Rats; Rats, Inbred Strains; Vitamin K Deficiency; Warfarin

Plasma and hepatic microsomal forms of rat prothrombin have been compared by sodium dodecyl sulfate-polyacrylamide electrophoresis and isoelectric focusing. The major prothrombin species that accumulated in the microsomes of rats treated with warfarin had a molecular weight of 78 500 and a pI in 8 M urea of 6.3-6.5. Plasma prothrombin had a molecular weight of 83 500 and a pI of 5.3-5.7. Microsomes from normal rat liver contain a second pool of precursor with a molecular weight of 83 500, and digestion with the glycosidase Endo H indicated that this form has been processed to contain complex carbohydrates, while the Mr 78 500 form is a high mannose form and is the substrate for the vitamin K dependent carboxylase. Treatment of rats with tunicamycin revealed that glycosylation was not essential for carboxylation or secretion from the liver. Comparison of the aglyco forms of prothrombin and its precursors suggests that the intracellular forms contain a basic, Mr approximately 1500 peptide that is missing from the plasma form of prothrombin.

Topics: Animals; Electrophoresis, Polyacrylamide Gel; Isoelectric Focusing; Male; Microsomes, Liver; Molecular Weight; Prothrombin; Rats; Tunicamycin; Vitamin K Deficiency; Warfarin

Munchausen by proxy has been reported involving children who have been given various drugs or toxins. In addition, there is a body of adult literature regarding covert anticoagulant ingestion. This is a case of an 11-month-old female who appears to combine features of both of these syndromes. This child presented with an acute left hemorrhagic otitis media. The physical examination was unremarkable except for the following: weight, fifth percentile; left external auditory canal filled with blood with the right external canal and tympanic membrane being normal; and several scattered 1 X 2 cm firm, movable, nontender, purple nodules on extremities, chest and forehead. The coagulation studies were consistent with Vitamin K deficiency secondary to anticoagulant ingestion. A serum warfarin study confirmed our suspicions. The mother was noted to have a dependent relationship with her child and characteristics of those involved in Munchausen by proxy: falsifying information and thwarting medical assessment. In addition, she displayed some of the characteristics found commonly in anticoagulant malingerers. She was depressed, with limited medical knowledge, and had access to warfarin. The mother was admitted for inpatient psychiatric care and the patient placed with an extended family member. This case report describes the use of an anticoagulant to induce illness in a child by a psychologically ill mother. This form of child abuse must be considered in the differential diagnoses of hemorrhagic disorders.

Topics: Adult; Blood Coagulation Disorders; Child Abuse; Diagnosis, Differential; Female; Humans; Infant; Munchausen Syndrome; Vitamin K Deficiency; Warfarin

Vitamin K is required for the post-translational formation of gamma-carboxyglutamyl residues in the vitamin K-dependent plasma clotting factors. Interference with vitamin K action results in the appearance of undercarboxylated, "abnormal," forms of prothrombin in bovine and human plasma, but the extent of this response in the rat has been controversial. Development of amidolytic and immunochemical assays for rat prothrombin have now shown that plasma from vitamin K-deficient or Warfarin-treated rats contains a non-BaSO4 adsorbable (undercarboxylated) pool of prothrombin that is equivalent to between 5 and 10% of the normal plasma prothrombin concentration.

Topics: Animals; Biomarkers; Male; Protein Precursors; Prothrombin; Rats; Rats, Inbred Strains; Vitamin K Deficiency; Warfarin

Hydroxy vitamin K [3(2)-hydroxy-2,3- dihydrovitamin K1] has been identified as a quantitatively important metabolite of injected vitamin K epoxide in vivo. The metabolite has been isolated and identified by comparison of its UV, mass spectra and high-performance liquid chromatography (HPLC) retention times with those of synthetic standards, and by its characteristic conversion to vitamin K quinone on treatment with the base triethylamine. This metabolite is formed from the vitamin K epoxide, not from the vitamin K quinone and can represent up to 3.5% of dose and 13% of hexane-extractable metabolites present in liver 1 hour after injection of 330 micrograms vitamin K1 epoxide per kilogram body weight. It is formed in both normal and warfarin-resistant rat strains, but to a significantly greater extent in the latter. Unlike the hydroxy vitamin K formed by warfarin-resistant rat liver microsomes in vitro, the metabolite formed from racemic vitamin K epoxide in vivo was not optically active, nor was its formation inhibited by coumarin anticoagulants under conditions that completely blocked vitamin K epoxide reduction in vivo. On this basis, hydroxy vitamin K formation in vivo differs from its formation in vitro; it is not a product of vitamin K epoxide reductase in vivo, but of some other possibly non-enzymatic reaction.

Topics: Animals; Chromatography, High Pressure Liquid; Drug Resistance; Liver; Male; Mixed Function Oxygenases; Rats; Vitamin K; Vitamin K 1; Vitamin K Deficiency; Vitamin K Epoxide Reductases; Warfarin

Topics: Animals; Drug Contamination; Papio; Skin; Skin Absorption; Talc; Vitamin K Deficiency; Warfarin

Chronic vitamin K deficiency, either dietary or pharmacologically induced with warfarin, depressed significantly the growth of lung secondaries in a spontaneously metastasizing murine tumor, the Lewis Lung Carcinoma. This effect was associated with a marked depression of the procoagulant activity of cancer cells, which could contribute to fibrin deposition around the tumor. Cellular anticoagulation may thus be an important mechanism in the antimetastatic effect of warfarin.

Topics: Animals; Blood Coagulation; Blood Coagulation Factors; Lung Neoplasms; Mice; Mice, Inbred C57BL; Neoplasm Metastasis; Neoplasms, Experimental; Vitamin K Deficiency; Warfarin

During prothrombin biosynthesis, glutamyl residues in prothrombin precursor proteins are carboxylated to gamma-carboxyglutamyl residues by a vitamin K dependent carboxylase. Calcium-dependent and calcium-independent rat prothrombin antibody subpopulations have been produced and utilized to study the liver microsomal precursors of prothrombin that accumulate when vitamin K action is blocked. A substantial portion of the precursor pool accumulating in the vitamin K deficient or warfarin-treated rat will react with a Ca2+-dependent antibody at high calcium concentration and appears to be partially carboxylated. During in vitro incubation in the presence of vitamin K, the fraction of the precursor pool which is tightly bound to the microsomal membrane appears to be the preferred substrate for the vitamin K dependent carboxylation. A small amount of completely carboxylated rather than a large amount of partially carboxylated products are produced during these incubations. Treatment with a Sepharose-bound prothrombin antibody demonstrated that about 20-25% of the total carboxylated microsomal protein precursor pool consists of prothrombin precursors. This treatment removes an equal amount of total carboxylase activity, and the enzyme is active in this carboxylase precursor-antibody complex.

Topics: Animals; Antibodies; Calcium; Carboxy-Lyases; Immunosorbent Techniques; Male; Microsomes, Liver; Protein Precursors; Prothrombin; Rats; Vitamin K; Vitamin K Deficiency; Warfarin

The dithiothreitol-dependent vitamin K and vitamin K 2,3-epoxide hepatic microsomal reductase activities of warfarin-susceptible and warfarin-resistant rats were compared to gain insight into the role(s) of these activities in vitamin K metabolism and function. In microsomes from resistant rats, 3- to 4-fold more warfarin was required to produce 50% inhibition (I50) of vitamin K reduction to vitamin K hydroquinone than in microsomes from susceptible rats. For the reduction of vitamin K 2,3-epoxide to vitamin K a 6-fold higher warfarin concentration was required. In microsomes from resistant rats, the I50 warfarin concentration required to inhibit gamma-carboxylation of microsomal precursor protein was also 4-fold higher with vitamin K as substrate and was 6-fold higher with the epoxide as substrate than in microsomes from susceptible rats. Collectively, these data suggest that the vitamin K reductase contributes to the metabolism of vitamin K in intact rats and that warfarin inhibition of both the vitamin K and vitamin K 2,3-epoxide reductases is involved in its anticoagulant effect.

Topics: Animals; Dithiothreitol; Drug Resistance; Kinetics; Male; Microsomes, Liver; Mixed Function Oxygenases; NAD(P)H Dehydrogenase (Quinone); Quinone Reductases; Rats; Vitamin K; Vitamin K Deficiency; Vitamin K Epoxide Reductases; Warfarin

Vitamin K-deficient animals and humans developed a more severe coagulopathy when treated with vitamin E, which was due to further reduction in the vitamin K-dependent coagulation factors (II, VII, IX, and X). This phenomenon was not seen in normal vitamin K-sufficient animals or human subjects. The mechanism by which vitamin E causes this effect is not known. These coagulation factors are produced by the liver in precursor forms and are converted to functional proteins by a vitamin K-dependent reaction. Analysis of one of these coagulation factors, prothrombin (factor II), in plasma of vitamin K-deficient animals and humans treated with vitamin E was done in this study. The precursor of factor II is antigenically similar to biologically active factor II and can be activated to form thrombin by Echis carinatus venom. The data showed that functional factor II coagulant activity was reduced below base in warfarin-treated humans and animals given vitamin E. Factor II antigen as determined by electroimmunoassay in humans and factor II coagulant activity as measured using Echis venom in animals were unchanged and no different from untreated controls. The data suggest that vitamin E acts at the vitamin K-carboxylase step of carboxylation of precursor prothrombin and not in the synthesis of the precursor protein.

Topics: Animals; Blood Coagulation; Dogs; Humans; Male; Prothrombin; Prothrombin Time; Rats; Rats, Inbred Strains; Vitamin E; Vitamin K Deficiency; Warfarin

Vitamin K-1 epoxide, the major metabolite of vitamin k-1, has similar activity to vitamin K-1 in inducing prothrombin synthesis and protein carboxylation. The high activity of K-1 epoxide could be due to its conversion to vitamin K-1 hydroquinone without going through vitamin K-1. A logical intermediate in this conversion would be vitamin K-1 epoxide-1,4-diol. The epoxide diol was synthesized and clearly stimulated prothrombin synthesis in vitamin K deficient rats at a minimum dose of 100 micrograms/kg body weight. Since vitamin K-1 produced a similar response at a minimum dose of 1 microgram/kg, the epoxide diol had about 1% of the activity of vitamin K-1. [3H]K-1 or [3H]epoxide could not be detected as metabolites of [3H]epoxide diol indicating that the activity of epoxide diol was probably not due to its conversion to K-1 hydroquinone, since any [3H]hydroquinone formed would be oxidized in air to [3H]K-1 during analysis. Vitamin K-1 epoxide diol represents a new type of structure possessing vitamin K activity. It is probably not active itself but has to be converted to an active compound since there is a delay in the response to the diol and the activity is completely blocked by Warfarin.

Topics: Animals; Prothrombin; Rats; Vitamin K; Vitamin K 1; Vitamin K Deficiency; Warfarin

Two siblings with m ild hemorrhagic symptoms had combined functional deficiencies of vitamin K-dependent clotting factors. Prothrombin (0.18-0.20 U/ml) and Stuart factor (Factor X, 0.18-0.20 U/ml) and Stuart factor (Factor X, 0.18-0.20 U/ml) were most severely affected. Antigenic amounts of affected coagulation factors were normal and normal generation of thrombin activity occurred in the patients' plasmas after treatment with nonophysiologic activators that do not require calcium for prothrombin activation. Hepatobilary disease, malabsorptive disorders, and plasma warfarin were not present. Both parents had normal levels of all coagulation factors. The patients' plasmas contained prothrombin that reacted both with antibody directed against des-gamma-carboxyprothrombin and native prothrombin. Crossed immunoelectrophoresis of patients' plasmas and studies of partially purified patient prothrombin suggested the presence of a relatively homogeneous species of dysfunctional prothrombin, distinct from the heterologous species found in the plasma of warfarin-treated persons. These studies are most consistent with a posttranslational defect in hepatic carboxylation of vitamin K-dependent factors. This kindred uniquely possesses an autosomal recessive disorder of vitamin K-dependent factor formation that causes production of an apparently homogeneous species of dysfunctional prothrombin; the functional deficiencies in clotting factors are totally corrected by oral or parenteral administration of vitamin K1.

Topics: Adolescent; Adult; Binding Sites; Calcium; Factor X Deficiency; Female; Hemophilia B; Humans; Hypoprothrombinemias; Immunoelectrophoresis, Two-Dimensional; Male; Partial Thromboplastin Time; Prothrombin; Prothrombin Time; Vitamin K Deficiency; Warfarin

gamma-Carboxyglutamic acid residues on prothrombin are synthesized from glutamic acid on a prothrombin precursor in the liver through a vitamin K-dependent carboxylase. In the absence of vitamin K or in the presence of vitamin K antagonists, an inert form of prothrombin - abnormal prothrombin - circulates in the blood. We have developed specific immunoassays for native and abnormal human prothrombin. The prothrombin concentration in our normal subjects was 108 +/- 19 microgram per milliliter. The abnormal-prothrombin concentration varied over four orders of magnitude between the limits of detection in normal plasma and the level in patients with cirrhosis (0 to 5 microgram per milliliter), acute hepatitis (0 to 33 microgram per milliliter), or vitamin K deficiency (32 to 100 microgram per milliliter) and in those treated with sodium warfarin (12 to 65 microgram per milliliter). These studies indicate that abnormal prothrombin is not a component of normal plasma but appears in a variety of hepatic and nutritional disorders characterized by impaired hepatic vitamin-K-dependent carboxylation.

Topics: Adult; Aged; Carbon-Carbon Ligases; Epitopes; Female; Hepatitis; Humans; Ligases; Liver; Liver Cirrhosis; Liver Diseases; Male; Middle Aged; Prothrombin; Prothrombin Time; Vitamin K Deficiency; Warfarin

Topics: Animals; Blood Coagulation Factors; Factor X; Lung Neoplasms; Mice; Mice, Inbred C57BL; Neoplasm Metastasis; Neoplasms, Experimental; Vitamin K; Vitamin K Deficiency; Warfarin

Four coagulation factors (II, VII, IX, X) are synthesized in the liver as precursor forms. Vitamin K is necessary for their conversion to functional factors. Factor II precursor is antigenically similar to factor II and can be activated to form thrombin by Echis carinatus venom. Forty-one patients with liver disease and 30 patients with vitamin K deficiency (Warfarin treated), were compared with 51 normal patients. Rats with CCl4-induced hepatic necrosis and animals given Warfarin were also studied. The following measurements were made: standard prothrombin time; Echis clotting time; factor II coagulant assay with thromboplastin; factor II assay with Echis venom; and factor II antigen (human) by electroimmunoassay. In animals and humans with liver disease, factor II was reduced, as measured by all techniques. With vitamin K deficiency functional factor II was reduced, but factor II antigen and Echis factor II activity were normal. THe data suggest that the prothrombin time and Echis coagulation methods can be used to differentiate whether the coagulopathy in liver disease is due to reduced precursor levels of factor II, vitamin K deficiency (ie, impaired formation of functional from precursor factor II), or both.

Topics: Animals; Antigens; Blood Coagulation Tests; Humans; Immunodiffusion; Liver Diseases; Prothrombin; Rats; Vitamin K Deficiency; Warfarin

Vitamin K-dependent carboxylation activity measured with pentapeptide substrate (Phe-Leu-Glu-Glu-Leu) gradually decreases upon in vivo injection of vitamin K to vitamin K-deficient rats. A decrease in pentapeptide carboxylation can also be observed by the in vitro addition of antibodies against prothrombin and other vitamin K-dependent proteins to the soluble system derived from vitamin K-deficient rat liver microsomes. In both cases, adding back in vitro partially decarboxylated vitamin K-dependent proteins or purified hepatic prothrombin precursor restores the level of pentapeptide carboxylation. After warfarin treatment, a 3-fold increase in carboxylation results, which can be abolished by giving cycloheximide along with the warfarin. However, the resulting decreased activity is restored by the in vitro addition of partially decarboxylated vitamin K-dependent proteins. These data are consistent with the hypothesis that (after warfarin treatment) increased peptide carboxylation is primarily due to activation of the system by precursor proteins, rather than synthesis of an increased amount of enzyme.

Topics: Animals; Antigen-Antibody Reactions; Carbon Dioxide; Cycloheximide; Hypoprothrombinemias; Immune Sera; Kinetics; Male; Microsomes, Liver; Oligopeptides; Proteins; Prothrombin; Rats; Vitamin K; Vitamin K Deficiency; Warfarin

Resistance to the anticoagulant rodenticide warfarin and an increased vitamin K requirement appear to be pleiotropic effects of the gene Rw2. A comparison of pup mortality in F2 (Rw1Rw2 x Rw1Rw2) and backcross (Rw1Rw2 x Rw1Rw1 or reciprocal) matings of wild brown rats in the laboratory revealed significantly greater losses in the F2 litters at 4-8 weeks of age. Some deaths could be attributed directly to haemorrhage resulting from vitamin K deficiency. A newborn warfarin-resistant rat from an F2 litter showed bleeding from the umbilicus and the anus, and died from internal haemorrhage at 18 weeks of age. Another warfarin-resistant male rat dying at the same age had a grossly enlarged skull.

Topics: Alleles; Animals; Animals, Newborn; Drug Resistance; Female; Male; Mortality; Pregnancy; Rats; Rodent Diseases; Vitamin K Deficiency; Warfarin

The cis and trans isomers of vitamin K1 have been prepared at a purity of better than 99.5% and tested for effect on plasma level of factor VII in coumarin anticoagulant-pretreated and vitamin K-deficient rats. Both isomers show activity, but in coumarin anticoagulant-pretreated animals the cis isomer has approximately 10% and in vitamin K-deficient approximately 1% of the activity of the trans isomer. The cis isomer also shows slower onset and rate of increase of the response. Reduction of the 2',3'-double bond of the phytyl side chain of either isomer to the same 2',3'-dihydro derivative of vitamin K1 leaves the activity of the trans isomer unchanged but increases the activity of the cis isomer to that of the trans isomer. The results suggest that the phytyl side chain not only serves to increase lipid solubility, but may play a more direct functional role.

Topics: Animals; Dose-Response Relationship, Drug; Drug Interactions; Factor VII; Oxidation-Reduction; Rats; Stereoisomerism; Time Factors; Vitamin K 1; Vitamin K Deficiency; Warfarin

Topics: 1-Carboxyglutamic Acid; Amino Acids; Animals; Blood Coagulation Disorders; Cycloheximide; Female; Half-Life; In Vitro Techniques; Male; Microsomes, Liver; Protein Biosynthesis; Prothrombin; Rats; Sex Factors; Vitamin K; Vitamin K Deficiency; Warfarin

Topics: Animals; Carbonates; Carboxylic Acids; Kinetics; Male; Microsomes, Liver; Oligopeptides; Pyridoxal Phosphate; Rats; Vitamin K Deficiency; Warfarin

Topics: Animals; Carbon-Carbon Ligases; Cattle; Chickens; Cricetinae; Drug Resistance; Glutamates; Guinea Pigs; Ligases; Male; Mice; Microsomes, Liver; Peptides; Prothrombin; Rabbits; Rats; Species Specificity; Swine; Vitamin K; Vitamin K Deficiency; Warfarin

The vitamin K-dependent hemostatic factors are present in reduced quantities at birth and may decrease further in the first few days of life. Administration of vitamin K1 on day 1 prevents hemorrhagic disease of the newborn. Maternal ingestion of anticonvulsants puts the newborn at greater risk from hemorrhage, possibly as a result of induction of fetal microsomal enzymes with a resultant increased oxidative degradation of vitamin K which gives rise to a vitamin K deficiency and other concomitant clinical results, for example skeletal defects. Evidence for this sequence of events is presented and the widespread effect of vitamin K deficiency on the fetus is discussed.

Topics: Abnormalities, Drug-Induced; Animals; Blood Coagulation Factors; Bone and Bones; Chick Embryo; Female; Hemostasis; Humans; Maternal-Fetal Exchange; Microsomes, Liver; Oxidation-Reduction; Phenytoin; Pregnancy; Vitamin K 1; Vitamin K Deficiency; Vitamin K Deficiency Bleeding; Warfarin

In the studies outlined in this report, normal dogs receiving megadoses of vitamin E displayed no abnormalities in their coagulation mechanisms. However, when made mildly vitamin-K-deficient by using warfarin, the introduction of vitamin E produced a profound coagulopathy. This coagulopathy was characterized by a further reduction in the vitamin-K-dependent coagulation factors and did not influence the levels of the non-vitamin K coagulation factors. Only one human case has been described to date, and this particular patients was vitamin-K-deficient at the time he was receiving vitamin E. Further studies are necessary to ascertain the usefulness of this vitamin in trombotic disease and to define the possible hematological toxicity in those patients with concomitant vitamin K deficiency.

Topics: Animals; Blood Coagulation; Dogs; Dose-Response Relationship, Drug; Humans; Injections, Intravenous; Middle Aged; Vitamin E; Vitamin K Deficiency; Warfarin

Topics: Animals; Drug Resistance; Glutamates; Ligases; Male; Microsomes, Liver; Mixed Function Oxygenases; Models, Biological; Oxidation-Reduction; Prothrombin; Rats; Vitamin K; Vitamin K Deficiency; Warfarin

When rats were given single or multiple doses of warfarin, the levels of prothrombin and factors VII, IX, and X were depressed, as expected. However, modest reductions of factors V, VIII, XI, and XII, but not of fibrinogen, also occurred. The levels of all eight factors promptly returned to normal when vitamin K1 was given. Warfarin-resistant rats had no depression of any of the eight factors. When vitamin K deficiency was induced by internal or external biliary fistula, factors II-VII-IX-X decreased sharply and factors V-VIII-XI-XII decreased modestly. Again, all depression were promptly reversed by vitamin K1. Isolated livers from warfarinized rats did not generate the classic vitamin K-dependent factors during 5 h of perfusion but did generate small amounts of factors V, XI, and XII, although less than normal. The isolated rat liver apparently does not generate factor VIII.

Topics: Animals; Dose-Response Relationship, Drug; Factor V; Factor VIII; Factor XI; Factor XII; Liver; Male; Perfusion; Rats; Vitamin K; Vitamin K Deficiency; Warfarin

Vitamin K is a component of a membrane-bound enzyme complex which catalyzes the posttranslational carboxylation of peptide-bound glutamate to form the gamma-carboxyglutamate (Gla) residues of prothrombin. The reaction requires reduced vitamin K, bicarbonate, oxygen, and a carboxylase, and does not require ATP. In a Triton X-100 solubilized carboxylase system, it was found that the naphthoquinone ring structure is essential for activity, as is the 2-methyl group. Menaquinone homologs from MK-1 to MK-4 all had carboxylase activity, whereas menadione was inactive. However, dithiothreitol and other thiols form thioethers with menadione, which restores considerable carboxylation activity to the provitamin. Hydrogenation of the beta-gamma double bond in phylloquinone reduced its activity only slightly. The active species of "CO2" utilized in this carboxylation is CO2 and not bicarbonate. Ribosomes contain Gla residues and are labeled with CO2 when whole microsomes are incubated with CO2 in the presence of NADH and vitamin K. About 25% of the activity is releasable with puromycin, suggesting that Gla residues are formed on both the nascent chains and the structural proteins of ribosomes. The deoxycholate-solubilized carboxylase system can be dialyzed to yield membranous vesicles with enhanced carboxylase activity. The warfarin-binding protein from normal rats, but not that from warfarin-resistant rats, further enhances the carboxylase activity of these reformed vesicles.

Topics: 1-Carboxyglutamic Acid; Animals; Carbon Dioxide; Carboxy-Lyases; Carrier Proteins; Glutamates; Intracellular Membranes; Microsomes, Liver; Peptides; Rats; Ribosomal Proteins; Structure-Activity Relationship; Vitamin K; Vitamin K Deficiency; Warfarin

Topics: Animals; Cytochrome P-450 Enzyme System; Cytosol; Kinetics; Liver; Male; Mass Spectrometry; Microsomes, Liver; Mixed Function Oxygenases; Prothrombin; Rats; Vitamin K; Vitamin K Deficiency; Warfarin

Vitamin K is required for an enzymatic carboxylation of glutamyl residues in a microsomal protein precursor of plasma prothrombin to form gamma-carboxyglutamic acid. The enzyme system (carboxylase) which catalyzes this reaction has now been solubilized by extraction of the microsomes with Triton X-100 and has been shown to fix H14CO3- as gamma-carboxyglutamic acid residues in biologically active prothrombin. Enzyme activity requires O2 and vitamin K hydroquinone or vitamin K + NADH. Unlike the microsomal-bound carboxylase, soluble carboxylase activity is independent of either ATP or Mg2+ addition and is unaffected by either the ATP analog, adenyl-5'-yl imidodiphosphate (AMP-P(NH)P, or EDTA. These observations suggest that the energy required to drive the carboxylation reaction is derived from the oxidation of the reduced form of vitamin K. Although the membrane-bound carboxylase is inhibited by Warfarin, this anticoagulant is ineffective as an inhibitor of the soluble enzyme. A second anticoagulant, 2-chloro-3-phytyl-1,4-natpthoquinone (chloro-K), differs from Warfarin in that it effectively inhibits both the membrane-bound and soluble carboxylases.

Topics: Adenosine Triphosphate; Animals; Carboxy-Lyases; Enzyme Activation; Kinetics; Liver; Magnesium; Oxygen Consumption; Polyethylene Glycols; Prothrombin; Rats; Solubility; Vitamin K; Vitamin K Deficiency; Warfarin

Topics: Amino Acids; Animals; Carbohydrates; Factor V; Factor X; Male; Microsomes, Liver; Phospholipids; Protein Precursors; Prothrombin; Rats; Thrombin; Vitamin K Deficiency; Warfarin

The incorporation of 14C-glucosamine and 3H-leucine into PIVKA-X and factor X has been studied in Macaca mulatta by means of a monospecific precipitating antiserum. No difference in the incorporation into PIVKA-X and factor X was found. The half-lives of PIVKA-X and factor X were similar (about 30-35 h and 27-31 h respectively) indicating that the vitamin K-induced modifications did not alter the survival of protein. A Russell's-viper venom/cephalin test system for factor X was more sensitive to inhibition by PIVKA-X than was a tissue thromboplastin-based system.

Topics: Adsorption; Animals; Barium Sulfate; Drug Stability; Factor X; Glucosamine; Half-Life; Haplorhini; Leucine; Macaca mulatta; Phosphatidylethanolamines; Protein Precursors; Vitamin K; Vitamin K Deficiency; Warfarin

The bovine plasma zymogen prothrombin contains a number of gamma-carboxyglutamic acid residues which are not found in an abnormal prothrombin produced when cattle are given the vitamin K antagonist dicoumarol. These modified glutamic acid residues appear to be formed post-translationally by a reaction which requires vitamin K. It has been shown that postmitochondrial supernates from vitamin K-deficient rats incorporate added H-14-CO3- minus into microsomal proteins upon the addition of vitamin K. This incorporation is dependent upon the presence of the prothrombin precursor in the microsomal preparations, and upon factors which are present in the postmicrosomal supernatant. Most of the radioactive protein which can be obtained from the microsomal pellet by extraction with 0.25% Triton X-100 has been identified as prothrombin and it can be shown that all of the radioactivity is in the amino-terminal activation fragment of prothrombin. This portion of the protein has previously been shown to contain the gamma-carboxyglutamic acid residues. Hydrolysis of the purified radioactive prothrombin resulted in a loss of 50% of the radioactivity and subsequent chromatography of the amino acid hydrolyzate demonstrated that the remaining radioactivity was entirely in glutamic acid. These results are consistent with the hypothesis that all of the H-14-CO3- minus was incorporated into the carboxyl groups of gamma-carboxyglutamic acid residues.

Topics: Animals; Bicarbonates; Carbon Radioisotopes; Cattle; Cytosol; Liver; Male; Prothrombin; Rats; Vitamin K; Vitamin K Deficiency; Warfarin

Two-week-old chicks adequate in vitamin K showed a relative lack of vitamin K-dependent clotting factors when compared with the rat, cow, and man. Chick prothrombin was 50%, IX 8%, and X 6% of respective levels in the rat. Factor VII was not detectable in chick plasma. When 1-day-old chicks were fed a vitamin K-deficient diet, prothrombin levels fell to 5% in 5 days, whereas factors IX and X fell to only 60% of normal. After warfarin administration to normal chicks, prothrombin levels fell to 20% in 6 hours, whereas factors IX and X fell to 60%. When cycloheximide was given to normal chicks, all vitamin K-dependent factors fell at the same relative rate with a half time of 2 hours. Cycloheximide also completely blocked the effect of physiological doses (10 mug) of phylloquinone upon prothrombin synthesis, but only partially blocked the effect of pharmacological doses (2.5 mg) of phylloquinone, suggesting an antagonism between cycloheximide and vitamin K at the ribosomal level. Puromycin was effective in blocking the action of vitamin K at both physiological and pharmacological doses. In the chick, unlike the rat, it appears that (1) cycloheximide is fully effective in blocking the action of physiological doses of vitamin K and (2) the regulatory systems for factors IX and X appear to have a higher affinity for vitamin K and a lower affinity for warfarin than the regulatory system for prothrombin.

Topics: Animals; Blood Coagulation Tests; Chickens; Cycloheximide; Dactinomycin; Factor IX; Factor X; Protein Biosynthesis; Prothrombin; Puromycin; Species Specificity; Time Factors; Vitamin K; Vitamin K 1; Vitamin K Deficiency; Warfarin

A dietary deficiency of vitamin K has been demonstrated in the Syrian hamster. This species has also been shown to be relatively resistant to the action of the indirect anticoagulant Warfarin, and very sensitive to the anticoagulant action of the vitamin K antagonist chloro-K. These observations, and the hamster's apparently high requirement for the vitamin, indicate that it responds to vitamin K and vitamin K antagonists in the same fashion as Warfarin-resistant strains of rats.

Topics: Animals; Anticoagulants; Blood Coagulation; Cricetinae; Diterpenes; Drug Tolerance; Male; Naphthoquinones; Prothrombin; Species Specificity; Vitamin K; Vitamin K 1; Vitamin K Deficiency; Warfarin

The oxidation of phylloquinone to the 2,3-epoxide (by phylloquinone epoxidase) was studied in liver from control and warfarin-resistant rats. The reaction requires microsomal fraction, soluble protein, a heat-stable soluble factor and O(2). It is not inhibited by CO or CN(-). Epoxidase activity was stimulated if plasma prothrombin was lowered either by anticoagulants or the absence of vitamin K. The activity of the enzyme rapidly returned to normal values after the administration of vitamin K to hypoprothrombinaemic rats. These differences in the activity of the enzyme occur in the microsomal fraction and not the cytosol. A thrombin-generating polypeptide that accumulates in microsomal fraction of hypothrombinaemic rats correlated directly with epoxidase activity. These data support the view that enzymic interconversion of phylloquinone and its 2,3-epoxide participates in the biological activity of vitamin K.

Topics: Animals; Anticoagulants; Blood Coagulation; Carbon Monoxide; Cyanides; Drug Resistance; Edetic Acid; Epoxy Compounds; Female; Flavin-Adenine Dinucleotide; Hypoprothrombinemias; Kinetics; Male; Microsomes, Liver; NAD; NADP; Oxidoreductases; Oxygenases; Proteins; Prothrombin; Rats; Vitamin K; Vitamin K 1; Vitamin K Deficiency; Warfarin

Topics: Amino Acids; Aminopeptidases; Animals; Bicarbonates; Carbon Dioxide; Carbon Radioisotopes; Chromatography, Ion Exchange; Electrophoresis, Disc; Glutamates; Hydrogen-Ion Concentration; Kinetics; Peptide Fragments; Pronase; Prothrombin; Rats; Time Factors; Trypsin; Vitamin K; Vitamin K Deficiency; Warfarin

Topics: Animals; Antimetabolites; Cycloheximide; Kinetics; Liver; Magnesium; Male; Potassium; Prothrombin; Rats; Subcellular Fractions; Time Factors; Vitamin K; Vitamin K Deficiency; Warfarin

Topics: Animals; Carbon Radioisotopes; Epoxy Compounds; Half-Life; Liver; Male; Proadifen; Prothrombin; Rats; Tritium; Vitamin K; Vitamin K Deficiency; Warfarin

Topics: Animals; Endoplasmic Reticulum; Liver; Male; Microscopy, Electron; Polyribosomes; Prothrombin; Rats; Ribosomes; RNA; Vitamin K 1; Vitamin K Deficiency; Warfarin

Topics: Blood Coagulation Disorders; Blood Coagulation Factors; Blood Coagulation Tests; Clofibrate; Hemorrhage; Humans; Male; Methods; Middle Aged; Prothrombin Time; Pulmonary Embolism; Sodium; Vitamin E; Vitamin K; Vitamin K Deficiency; Warfarin

Topics: Animals; Anticoagulants; Coumarins; Ethers, Cyclic; Hypoprothrombinemias; Male; Microsomes, Liver; Prothrombin; Rats; Structure-Activity Relationship; Tritium; Vitamin K; Vitamin K 1; Vitamin K Deficiency; Warfarin

Topics: Animals; Antibodies; Antigens; Biomarkers; Chromatography, Affinity; Cross Reactions; gamma-Globulins; Microsomes, Liver; Molecular Weight; Protein Precursors; Prothrombin; Rats; Sodium Dodecyl Sulfate; Thrombin; Vitamin K Deficiency; Warfarin

Topics: Albinism; Animals; Blood Coagulation Tests; Chromosome Mapping; Crosses, Genetic; Drug Resistance; Female; Genotype; Heterozygote; Homozygote; Liver; Male; NADH, NADPH Oxidoreductases; Quinones; Rats; Recombination, Genetic; Time Factors; Vitamin K; Vitamin K Deficiency; Warfarin

Topics: Animals; Blood Coagulation Tests; Chromatography, DEAE-Cellulose; Electrophoresis, Disc; Hirudins; Hypoprothrombinemias; Immunodiffusion; Liver; Male; Microsomes, Liver; Protein Precursors; Prothrombin; Rabbits; Rats; Snakes; Spectrophotometry, Ultraviolet; Thrombin; Time Factors; Venoms; Vitamin K; Vitamin K Deficiency; Warfarin

Topics: Animals; Blood Coagulation Tests; Drug Resistance; Female; Homozygote; Hybridization, Genetic; Hypoprothrombinemias; Injections, Subcutaneous; Male; Nutritional Requirements; Rats; Rodent Diseases; Vitamin K; Vitamin K Deficiency; Warfarin

Topics: Animals; Chlorine; Drug Resistance; Female; Hypoprothrombinemias; Male; Naphthoquinones; Prothrombin; Rats; Rats, Inbred Strains; Sex Factors; Vitamin K; Vitamin K Deficiency; Warfarin

Topics: Adult; Aged; Alcoholism; Evaluation Studies as Topic; Fatty Liver; Female; Hemorrhage; Humans; Hypoprothrombinemias; Liver Cirrhosis; Male; Middle Aged; Prospective Studies; Prothrombin; Prothrombin Time; Vitamin K Deficiency; Warfarin

Topics: Amino Acids; Animals; Barium Sulfate; Blood Protein Electrophoresis; Blood Proteins; Chromatography, DEAE-Cellulose; Electrophoresis, Disc; Hypoprothrombinemias; Male; Prothrombin; Rats; Rats, Inbred Strains; Time Factors; Vitamin K Deficiency; Warfarin

Topics: Animals; Binding Sites; Carbon Isotopes; Centrifugation, Density Gradient; Chlorine; Male; Membranes; Microsomes, Liver; Osmolar Concentration; Phospholipases; Phospholipids; Protein Binding; Rats; Rats, Inbred Strains; Ribosomes; RNA; Vitamin K 1; Vitamin K Deficiency; Warfarin

Topics: Adsorption; Animals; Barium Sulfate; Cycloheximide; Electrophoresis, Disc; Kinetics; Male; Microsomes, Liver; Prothrombin; Prothrombin Time; Rats; Vibration; Vitamin K; Vitamin K Deficiency; Warfarin

Topics: Animal Nutritional Physiological Phenomena; Animals; Carbon Isotopes; Cell-Free System; Coumarins; Dactinomycin; In Vitro Techniques; Iodine Isotopes; Male; Microsomes, Liver; Peptide Chain Elongation, Translational; Peptide Chain Initiation, Translational; Prothrombin; Radioimmunoassay; Rats; Time Factors; Vitamin K; Vitamin K Deficiency; Warfarin

Topics: Adult; Animals; Drug Resistance; Female; Humans; Hypoprothrombinemias; Male; Middle Aged; Prothrombin Time; Rats; Vitamin K; Vitamin K Deficiency; Warfarin

Topics: Antibodies; Antigen-Antibody Reactions; Antigens; Blood Coagulation Tests; Blood Proteins; Factor VII; Factor VII Deficiency; Humans; Immune Sera; Liver Diseases; Neutralization Tests; Vitamin K Deficiency; Warfarin

Topics: Amino Acids; Animals; Barium Sulfate; Blood Proteins; Carbon Isotopes; Electrophoresis, Disc; Glucosamine; Male; Mannose; Metabolism; Prothrombin; Rats; Tritium; Vitamin K; Vitamin K Deficiency; Warfarin

Topics: Animals; Carbon Isotopes; Male; Oxides; Prothrombin; Rats; Time Factors; Tritium; Vitamin K; Vitamin K 1; Vitamin K Deficiency; Warfarin

Topics: Animals; Blood Coagulation Factors; Cycloheximide; Factor IX; Factor VII; Factor VIII; Factor X; Liver; Male; Methods; Oxygen Consumption; Puromycin; Rats; Vitamin K; Vitamin K Deficiency; Warfarin

Topics: Animals; Blood Coagulation Tests; Cycloheximide; Dactinomycin; Depression, Chemical; Liver; Male; Metabolism; Naphthoquinones; Protein Biosynthesis; Prothrombin; Rats; RNA; Stimulation, Chemical; Time Factors; Tritium; Vitamin K; Vitamin K 1; Vitamin K Deficiency; Warfarin

Coumarin anticoagulants inhibit the release of plasma clotting factor VII by vitamin K in liver slices from vitamin K-deficient animals without inhibition of protein synthesis. When the ratio of vitamin K to coumarin anticoagulant is kept constant, but the concentrations are increased, the inhibition disappears. This suggests that the pharmacological action of coumarin anticoagulants depends on irreversible inhibition of normal vitamin K transport to its site of action. At higher concentrations of vitamin K the inhibition can be surmounted, because vitamin K can enter the cell by an alternate route that is not inhibited by coumarin anticoagulants.

Topics: Animals; Anticoagulants; Biological Transport; Carbon Isotopes; Coumarins; Depression, Chemical; Factor VII; In Vitro Techniques; Leucine; Liver; Protein Biosynthesis; Rats; Vitamin K; Vitamin K 1; Vitamin K Deficiency; Warfarin

Topics: Animals; Cell Nucleus; Centrifugation; Chromatography; Detergents; Endoplasmic Reticulum; Liver; Microsomes; Mitochondria, Liver; Naphthoquinones; Prothrombin; Rats; Ribosomes; Solubility; Spleen; Time Factors; Tritium; Vitamin K; Vitamin K 1; Vitamin K Deficiency; Warfarin

Topics: Amino Acids; Animals; Carbon Isotopes; Cycloheximide; Dactinomycin; Dicumarol; Liver; Male; Microsomes; Mitochondria, Liver; Protein Biosynthesis; Prothrombin; Prothrombin Time; Puromycin; Rats; Time Factors; Ultrasonics; Vitamin K; Vitamin K Deficiency; Warfarin

Topics: Antibodies; Antigens; Coagulase; Humans; Immune Sera; Immunodiffusion; Prothrombin; Vitamin K Deficiency; Warfarin

Topics: Animals; Dicumarol; In Vitro Techniques; Lipid Metabolism; Liver; Microsomes; NADP; Oxygen Consumption; Peroxides; Polarography; Rats; Vitamin K Deficiency; Warfarin