[Thrombotic complications in the blocking effect of protamine sulfate on nonenzymatic fibrinolysis in the blood of animals during activation of the anticoagulation system].

Protamine-sulfate blocked non-enzymatic fibrinolysis not only in vitro but also in vivo through binding of heparin and dissociation of its complexes, which are of great importance as humoral components of the anticoagulation system. Almost complete blocking of humoral agents of the anticoagulation system, caused either by a single intravenous administration of protamine-sulfate at large doses or by repeated administration of the substance at moderate doses within 14 days, led to death of the animals as a result of thrombotic complications related to appearance of additional thrombin in blood circulation. In these cases thrombosis occurred into coronary blood vessels. The non-enzymatic fibrinolytic effect was not observed in extracts from lungs, auricula atrii and liver tissue of experimental animals, treated with protamine-sulfate, as compared with the controls, administered with physiologic solution.