Effects of Ancrod (Arvin) in mice: studies of plasma fibrinogen and fibrinolytic activity.

Abstract

Summary.Plasma fibrinogen and its degradation products (FDP) were examined in mice given single injections of Ancrod, the purified coagulative fraction of Malayan pit viper venom previously called Arvin. Clottable fibrinogen had disappeared completely 5 min after the injection and slowly reappeared 12 hr later. At least 2 FDP appeared in the plasma 30 min after the injections while 5 hr later only one FDP was present which corresponded to human fragment E. This was in contrast to in vitro lysis of mouse fibrinogen which yielded two late FDP corresponding to human fragments D and E.The fibrinolytic system also was examined in the plasma of these animals. 30 min after the injection, plasminogen was decreased in amount but increased in susceptibility to activation by urokinase. Transient, modest increases in fibrinolytic activity were evident in diluted plasma samples 1 hr and again 8 hr after the injections. Inhibitors of fibrinolysis did not differ from those in normal mice.These observations are correlated with our previous immunofluorescent and histochemical studies on these and other animals. The present data support our earlier conclusion that fibrinolysis within small vessels of the tissues is of major importance in the reaction to Ancrod.