The effects of the use of Paritol administered intravenously to 35 individuals are herein reported. This synthetic anticoagulant produces a prolongation of the clotting time similar to that produced by heparin but of longer duration, if appropriate dosage is used. As with heparin, at therapeutic clotting time levels, the prothrombin time is slightly prolonged. Certain untoward effects have been...

The development of portable instruments for measuring the prothrombin time (PT) in capillary whole blood has made it possible for patients on lifelong coumarin therapy to monitor the effect of the anticoagulant themselves (patient self-testing) and to adjust the dosage if necessary on their own (patient self-management). Dosage variations between individual patients and the narrow therapeutic r...

AIMS To evaluate an easier alternative method to orthogonal regression analysis for calculating International Sensitivity Indexes (ISI). METHODS ISI for 18 reagents were estimated from reference and test reagent prothrombin times using plasma from 60 stabilised patients undergoing anticoagulation therapy and 20 normal subjects. ISI were also derived for 12 systems (instrument/reagent combinat...

Thrombin generation was studied in paediatric patients with congenital heart disease (CHD) undergoing cardiac surgery using the calibrated automated thrombography (CAT) in terms of the lag time until the onset of thrombin formation, time to thrombin peak maximum (TTP), endogenous thrombin potential (ETP), and thrombin peak height. The suitability to determine the coagulation status of these pat...

The prothrombin gene mutation G20210A is a common risk factor for thrombosis and is associated with increased prothrombin levels. However, the mechanism whereby hyperprothrombinemia predisposes to thrombosis remains unclear. Because thrombin is the physiologic activator of TAFI (thrombin activatable fibrinolysis inhibitor), the precursor of an antifibrinolytic carboxypeptidase (TAFIa), we evalu...

To study the specific role of gamma-carboxyglutamic acid (Gla) residues in prothrombin, we have isolated a series of partially carboxylated prothrombin variants from a patient with a hereditary defect in vitamin K-dependent carboxylation (Goldsmith, G. H., Pence, R. E., Ratnoff, O. D., Adelstein, D. A., and Furie, B. (1982) J. Clin. Invest. 69, 1253-1260). The three variant prothrombins, purifi...

AIMS To examine the magnitude of thromboplastin and coagulometer interactions on the precision of International Normalised Ratio (INR) values when the manufacturers' recommended instrument specific International Sensitivity Index (ISI) values are adopted for the INR calculation. METHODS The variability of INR values obtained from four automated phototopical coagulometers frequently used in No...

Recombinant hirudin (r-hirudin) is being used increasingly for therapeutic anticoagulation in patients with heparin-induced thrombocytopenia undergoing cardiovascular surgery. Although multiple laboratory methods are available for measuring r-hirudin, the ecarin clotting time (ECT) is the most commonly used for this purpose. Ecarin (extracted from snake venom) converts prothrombin to meizothrom...