Fibrinolytic activity in thrombosed veins.

• Since Virchow's observation o idity and incoagulability of cadaver capillaries and veins, a number of re indicated that this phenomenon is cau postmortem fibrinolysis. Mole suggest the vascular endothelium is a source fibrinolytic activity in cadaver blood. Kwaan et al.' applied stimuli to in man and in rabbits and obse lease of fibrinolytic activity thr< cholinergic mechanism. Release o activity from the human vein wall chanical trauma was reported by C et al. More specifically, Astrup et onstrated a plasminogen activator in the adventitia of arteries and veins, and in the intima of veins. The latter finding was also reported by Messer et al. Using a histochemical method, Todd" found the plasminogen activator in tissues localized to the small veins and the venous endothelium. This finding has been confirmed.' The recent demonstration that plasminogen activator is brought into an area of tissue repair by the newly formed capillaries suggested that such a situation could exist in an organizing thrombus. Presumably, in a venous thrombus, capillaries originating from the venous endothelium would invade the thrombus, bringing with them fibrinolytic active endothelial cells, thus assisting in the resolution of fibrin. The present