Comparison of the relative fibrinogenolytic, fibrinolytic and thrombolytic properties of XXXX and urokinase in vitro.

@entity1 @entity1456 @entity320
The relative fibrinogenolytic, fibrinolytic and thrombolytic properties of @entity1 @entity1456 and @entity1 urokinase were compared in purified systems, in whole @entity1 plasma and in a system composed of a radioactive @entity1 blood clot (125I-fibrinogen) hanging in circulating @entity1 plasma. The @entity1 @entity1456 was highly purified from the culture fluid of a @entity1 @entity320 cell line. In purified systems composed of fibrinogen of fibrin, plasminogen and alpha 2-antiplasmin as well as in whole plasma, @entity1456 digested fibrin without degrading fibrinogen significantly. Urokinase did not have this specific fibrinolytic effect. In the circulating plasma system, the degree of fibrinolysis was proportional to the amount of activator added, @entity1456 being about 10 times more efficient than urokinase. In addition, @entity1456 appeared to cause negligible fibrinogen degradation. @entity1456 still induced significant thrombolysis at a concentration of 10 IU per ml whereas no effect of urokinase was observed at 20 IU per ml. Infusion of 100 IU (1 microgram) of @entity1456 per ml resulted in moderate activation of the fibrinolytic system as judged from a decrease of plasminogen and alpha 2-antiplasmin to 40-50 percent. Nevertheless, extensive fibrinolysis (50 to 80 percent of radioactivity released after 12 hrs) and only very limited fibrinogenolysis were observed. An equivalent amount of urokinase (100 IU per ml) only induced approximately 15 percent lysis in 12 hrs. At higher concentrations of urokinase (260 IU per ml or more) extensive activation of the fibrinolytic system was obtained as evidenced by a depletion of plasminogen, alpha 2-antiplasmin and fibrinogen. This was associated with extensive fibrinolysis (approximately 60 percent after 12 hrs). It is concluded that @entity1 @entity1456 is a more specific and effective fibrinolytic-thrombolytic agent than @entity1 urokinase.
