Summary and Conclusions
Dogs and rabbits were infused with acetylated thrombin (thrombin E) and clotting thrombin
(thrombin C). Similar effects were noted in both animal series. Very large amounts
of thrombin E could be tolerated, but resulted in defibrination. Following a transient
hypercoagulable state, the blood became unclottable. The platelets and factors I,
V, and VIII were markedly decreased. Factor II was moderately affected and factor
VII-X showed no significant changes in most experiments. The presence of fibrinogen
degradation products was indicated by a delay in the polymerization of fibrin monomers.
Based on the shortening of the euglobulin lysis time, a decrease in the proactivator,
and the appearance of inhibitors of fibrin monomer polymerization, it is concluded
that transient fibrinolysis is induced by the infusion of thrombin. Its immediate
mechanism could not be determined.