Prothrombin blocking

Mechanism of Action A blood modifier that interferes with blood coagulation by blocking conversion of prothrombin to thrombin and fibrinogen to fibrin Therapeutic Effect Prevents further extension of existing thrombi or new clot formation. Has no effect on existing clots. 

Second generation anticoagulant rodenticide which also blocks prothrombin formation... 

Blocks prothrombin formation and uncouples oxidative phosphorylation... 

In this equation, kd is the apparent first-order degradation rate constant (also called out). This constant can be obtained experimentally from the slope of a ln(P) versus time plot, after administration of a synthesis-blocking dose of coumarin anticoagulant (Nagashima et al., 1969 Pitsui et al., 1993). P0 is the baseline value of the prothrombin time, Cw(S) is the concentration of ( -warfarin and IC50s is the concentration of warfarin at 50% of maximal blocking effect. It was also possible to estimate the half-life of the apparent first-order degradation. 

Warfarin is active orally. Il is a coumiirin derivative with a siniciure similar 10 that of vitamin K. Warfarin blocks vitamin K-dependent 7-carboxylaiion of glutamate residues (top. shaded). resulting in the production of modified factors VI I. IX. X and prothrombin (U). These arc inactive in promoting coagulation because the y-carbo.xylaiion confers Ca -hinding properties that are essential for the proteins to assemble... 

Platelets in the blood send a message to constrict blood vessels in the area surrounding a wound. Platelets gather to block the flow of blood coming out. At the same time, a chemical messenger called prothrombin activates an enzyme called thrombin, which then produces a species called fibrin. Fibrin forms threads to block the wound even better. 

The coumarin anticoagulants are employed in therapy to depress blood coagulation and to prevent thrombosis in diseases of the coronary artery and in other conditions [419]. These compounds act only in vivo by blocking the synthesis of four proteins in the prothrombin complex (factors II = prothrombin, VII = proconvertin, IX = plasma thromboplastin component, and X = Stuart-Prower factor) necessary for the normal blood coagulation process. These proteins are... 

Blocking the action of thrombin prevents conversion of fibrinogen to fibrin (52). Thrombin inhibitors are produced by the salivary glands of Ixodes holocyclus 61), Ixodes ricinus 62), A. americanum 63), and 0. savignyi 64). Dermacentor andersoni salivary glands contain inhibitors of factor V, an integral part of the complex with Xa that converts prothrombin to thrombin, and factor Vn, a component of the extrinsic pathway 65). Omithodoros moubata produces inhibitor of the intrinsic pathway component,... 

Prothrombin is produced in the liver by a process which requires vitamin K. The drug dicumarol blocks the action of vitamin K consequently little prothrombin is made available and the clotting time is prolonged. 

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