Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.21.5 (thrombin)
 33,306 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The protein C activity assay of Francis and Patch (Thromb Res 1983; 32: 605-613) is based on the prolongation of the activated partial thromboplastin time in the presence of activated protein C isolated from the test samples. The assay was modified and standardized by Rapaport et al. (Am J Clin Pathol 1987; 87: 491-497), but could still only be used in patients on heparin therapy after chromatographic removal of the heparin. In this study we attempted to eliminate the heparin separation step without losing the advantages of the modified (Rapaport) method. Heparin was added to the isolated protein C to obtain a rapid and complete antithrombin effect after the thrombin activation step and polybrene was subsequently used to neutralize the excess heparin. Using this modified assay protein C activity ranged from 67 to 133% in the normal population, and from 9 to 25% in coumarin-treated patients. Precision of the modified method was acceptable in both normal and pathological PC ranges: within- and between-batch variations were 5.6 and 3.6%, and 8 and 14%, respectively. The assay correlated well (r = 0.84) with the ELISA technique in both healthy donors and non-coumarin-treated patients.
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PMID:The use of polybrene for heparin neutralization in protein C activity assay. 213 12

The efficacy of three different protein C activity assays and of protein C antigen determination for the diagnosis of protein C deficiency was studied in 13 protein C deficient patients (11 with type I, 2 with type II deficiency) and in 51 presumably non-deficient patients (control group), both groups being on oral anticoagulant (OAC) treatment. For protein C activity measurement (1) the assay according to Francis (slightly modified) with thrombin activation and measurement of activated protein C in the aPTT system, (2) an assay using Protac activation and chromogenic substrate (Protac-CS) and (3) an assay using Protac activation and the aPTT system (Protac-PTT) were used. Protein C antigen was determined by Laurell immunoelectrophoresis. The three activity assays gave different results, with the highest values obtained by the Protac-CS assay and the lowest values by the Protac-PTT assay. The Francis assay gave intermediate results. Protein C activity and antigen values were significantly lower in protein C deficient patients compared to the control group. Protein C activity tests had a higher discriminative power than the antigen determination. After taking into account the intensity of treatment, by the Francis assay all deficient and non-deficient patients were correctly classified, by the Protac-CS and the Protac-PTT assay 2 and 4 patients, respectively, were misclassified and by the antigen assay 8 patients were misclassified. Calculation of the ratios of protein C activity to factor II activity was of high discriminative power. We conclude that for diagnosis of protein C deficiency protein C activity tests are superior to antigen determination not only in type II but also in type I deficient patients.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Diagnosis of protein C deficiency in patients on oral anticoagulant treatment: comparison of three different functional protein C assays. 240 42

Advances in vascular biology and drug development, as well as improved interventional techniques, are yielding multiple new treatments for patients with venous and/or arterial thrombosis. Hematologists who are providing consultations for these patients often participate in a multidisciplinary approach to provide optimal care. New anticoagulants, simplified and validated tests for detecting vascular disease, and improved interventional procedures can all reduce the morbidity and mortality that result from venous and arterial thrombosis. In this chapter, different aspects of the diagnosis and treatment of these disorders are addressed by a hematologist, an expert in vascular medicine, and a vascular surgeon. The key to the prevention and treatment of venous and arterial thrombosis is anticoagulant and antiplatelet therapy. In Section I, Dr. Charles Francis, a hematologist with expertise in thrombosis and hemostasis, describes the clinical trials that have resulted in the approval of newer anticoagulants such as fondaparinux and the thrombin- specific inhibitors. He also reviews the clinical trials that have shown the efficacy of the new oral anticoagulant ximelagatran. Although currently under study primarily for the prevention and treatment of venous thrombosis, these anticoagulants are likely to undergo evaluation for use in arterial thrombosis. Peripheral arterial disease (PAD), which affects as many as 12% of individuals over the age of 65 years, provides a diagnostic and therapeutic challenge to physicians across multiple subspecialties. Dr. William Hiatt, a specialist in vascular medicine, discusses in Section II the epidemiology and manifestations of PAD, the best ways in which to diagnose this disorder and determine its severity, and the most appropriate pharmacologic treatment. In Section III, Dr. Mark Jackson, a vascular surgeon, describes interventional procedures that have been developed or are under development to treat arterial thrombosis. He also reviews the status of inferior vena caval filters that are retrievable.
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PMID:Consultations on patients with venous or arterial diseases. 1463 98

Vitamin K, heparin and their antagonists remain the basis of coagulation therapies today, more than half a century after their discovery. Failure of blood clotting in chicks that were fed a fat-depleted diet was observed by William McFarlane, William Graham Jr. and Frederick Richardson of the Ontario Agricultural College; it led to the search that yielded vitamin K. Investigation of hemorrhagic disease in cattle by Francis Schofield of the Ontario Veterinary College found an anti-thrombin substance in spoiled clover which was later characterized as dicoumarol, a vitamin K antagonist, and led to the development of warfarin. In Toronto, a systematic approach lead by Charles Best resulted in the world's first plentiful supply of purified heparin. Clinical usefulness of heparin in thrombosis, embolism, cardiovascular surgery, dialysis and transplantation was demonstrated first by Gordon Murray and Louis Jaques. The roles and the careers of Canadian coagulation research pioneers are briefly presented in this review, which shows how clinical medicine benefited by the systematic development of agricultural science in Guelph, Ontario.
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PMID:Control of coagulation: a gift of Canadian agriculture. 1733 Apr 53