The plasminogen activator of the arterial wall.

The plasminogen activator in 645 specimens of various human arteries--thoracic, abdominal aorta, carotic, pulmonary, renal, basilar, coronary - was studied using Todd's histochemical method. 92 cadavers were used, 1--18 hours post mortem from subjects aged from 272 days to 83 years. 45 specimens of pulmonary, renal and splenic arteries were obtained during surgery. The greatest fibrinolytic activity was within the adventitia. Intima occasionally showed very little fibrinolytic activity, or none at all. No statistically significant differences in plasminogen activator activity were found between the various arteries examined. A statistically significant increase in fibrinolysis in adventitia of atherosclerotic arteries was established. No correlation was found between the fibrinolytic activity of the arteries and their alkaline phosphatase content. Some properties of the plasminogen activator of the arterial vessel wall were evaluated. Influence of storage, inactivation with epsilonaminocaproic acid and extracted with potassium thiocyanate was studied.