In vitro and in vivo studies on the effects of Defibrase (snake venom, Bothrops Marajoensis) on coagulation, fibrinolysis and platelets, and its defibrinogenating activity, compared with those of thrombin

In vitro and in vivo studies obtained on the effects of Defibrase on coagulation, fibrinolysis and platelets, and its defibrinogenating activity, compared with those of thrombin were performed.The following results were:1) Normal citrated human plasma clotting activity with Defibrase was weaker than that with thrombin on the basis of the same NIH units.2) There were no effects on coagulation and fibrinolysis of plasma by Defibrase, but the decrease of factor V and factor VIII activity were observed dy thrombin as a serine protease. 0.16units/ml of Defibrase and thrombin in final concentration were used in this experiment.3) There was found that the susceptibility of fibrin clotted by Defibrase by fibrinolytic enzymes (urokinase, streptokinase and plasmin) was stronger than that of fibrin clotted by thrombin.These facts were observed by fibrin plate method using plasminogen rich fibrinogen and plasminogen free fibrinogen, and platelet aggregation examined by using EL-aggregometer.4) In vivo studies using rabbit, there were observed decreases of factor VIII, fibrinogen, platelets and ratio of platelet retention to glass beads column.From these results it was concluded that Defibrase would be effective in defibrination of blood without making hypercoagulation and hyperfibrinolysis. And also decreases of factor VIII, platelet count and platelet retention ratio were observed in vivo study by infusion of Defibrase into rabbits.