Plasma prothrombin

Poot S. R Rosendaal F. R., Reitsma P. H Bertina R. M. A common genetic variation in the 3 -untranslated region of the prothrombin gene is associated with elevated plasma prothrombin levels and an increase in venous thrombosis. Blood 1996 88,3698-703. 

The fibrates potentiate the actions of the coumarin anticoagulants, such as warfarin, so care should be taken to reduce the dose of simultaneously administered anticoagulants, and plasma prothrombin should be frequently measured until the level stabilizes. As mentioned earlier, great care should be given to combining a statin with a fibrate, since this combination may increase the risk of myositis and perhaps rhabdomyolysis. Table 23.4 summarizes major interactions of drugs that lower cholesterol. 

Potentates coumarin anticoagulants. Therefore, reduce dose of anticoagulant and monitor plasma prothrombin. 

Soria JM, Almasy L, Souto JC, et al. Linkage analysis demonstrates that the prothrombin G20210A mutation jointly influences the plasma prothrombin levels and risk of thrombosis. Blood 2000 95(9) 2780-2785. 

NS) Cont. Hemato 0.13 (increased plasma prothrombin and fibrinogen) U02(N03)2 6H20... 

Vitamin E therapy in vitamin K-deficient subjects and subjects taking anticoagulants reduces active plasma prothrombin concentrations (44). 

Cattaneo M, Chantarangkul V, Tailoi E, Santos JH, Tagliabue L. The G20210A mutation of the prothrombin gene in patients with previous first episodes of deep-vein thrombosis prevalence and association with factor V G1691 A, methylenetetrahy-drofolate reductase C677T and plasma prothrombin levels. Thrombo Res 1999 93 1-8. 

Tl. Tocantins, L. M., and O Neill, J. F., Increased plasma prothrombin activity after epinephrine injections relation to hyperglycemia. Proc. Soc. ExpU. Biol. Med. 47, 477-479 (1941). 

Ul. Unv s, B., The plasma prothrombin level in cats and rabbits after excluding the liver from the circulation, after stimulation of the splanchnic nerve and after intravenous injection of adrenalin. Acta Physiol. Scand. 8, 97-110 (1942). 

Alcoholic and aqueous extracts of safflower inhibited ADP-and collagen-induced aggregation of rabbit and rat platelets (Zhu 1998). The food colorant safflower yellow inhibited ADP-induced platelet aggregation in rabbit blood platelets and prolonged the rabbit plasma prothrombin time (Zang et al. 2002). 

Compound Action, day Onset Peak Duration Peak plasma prothrombin level % ... 

Ac-globulin thrombogen factor V labile factor component A of prothrombin prothrombin accelerator proacce-lerin accelerator factor plasma prothrombin conversion factor plasmatic cofactor of thromboplastin prothrom-binase... 

Prothrombin, the precursor of thrombin, is present in plasma only in small amounts (0.2% of the protein content of plasma) and can be purified by acid precipitation by adsorption on magnesium hydroxide and fractionation with ammonium sulfate. The purified protein contains glucose (6.5%), neuraminic acid (5%), and unidentified amino sugars. A study of the amino acid composition reveals that the molecule contains 19 different amino acids. Prothrombin has only one N-terminal amino acid (alanine), and no carboxy C-terminal can be detected by hydrolyzing the molecule with carboxypeptidase A or B. Prothrombin is an ellipsoid molecule (119 A x 34 A) with a molecular weight of 62,700. On electrophoresis of plasma, prothrombin migrates between the a2- and the jS-globulin. 

NaOH treatment could significantly enhance the blood compatibility of PHBHHx by prolonging plasma recalcification time, plasma prothrombin time, and kinetic clotting time and by decreasing platelet activation. By comparison, PHBHHx exhibited a substantially better blood compatibility than poly(L-lactic acid) [58]. 

Interesting findings were recently reported by S0rbye and associates in a study of the factors concerned in the normal clotting mechanism. They isolated from the plasma of vitamin K-deficient chicks a protein factor, designated the kappa factor which reduced plasma prothrombin time in animals treated with bishydroxycoumarin (dicumarol) but which had no effect upon prothrombin time in vitamin K deficiency. A second factor, the delta factor, was isolated from plasma of chicks treated with dicumarol which reduced prothrombin time of plasma of vitamin K-deficient chicks but not that of plasma from chicks receiving dicumarol. They postulated that at least four factors are necessary in the clotting mechanism prothrombin proper, the kappa and delta factors, and the labile factor of fresh plasma (factor V). Deficiency of vitamin K apparently produced a defect in the delta factor, while administration of dicumarol produced a deficiency of the kappa factor. 

Genetically determined resistance to warfarin has been observed both in man and rats. Although absorption, plasma concentration and protein binding as well as the metabolism of the drug are all within the normal range, doses 10 times higher must be administered in order to obtain the same decrease in plasma prothrombin as in normal individuals. 

The blood clotting time and plasma prothrombin time prolongation in GrII and Grill 60 min. p.i. (Table 2) may be attributed to the hemolysin factors present in the crude venom Shiomi etai, 1986 Al-Lahhame a/., 1987 Al-Hassan a/., 1987b andKhoo 1992). 

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