Susceptibility to Thrombosis in Normal Young, Aging, Cortisone-treated, Heparinized and X-irradiated Hamsters as Tested by Topical Application of Thrombin

Abstract

Abstract 1. Thrombin applied topically to the everted cheek pouch of the hamster produced platelet and not red thrombi in exposed, uninjured blood vessels with circulating blood. Red thrombi were produced in stagnant blood. Thrombus formation occurred in the venules for the most part and seldom in arterioles or capillaries. 2. An in vivo test for platelet thrombus susceptibility, based on the thrombin reaction and the resistance of the hamster to thrombosis, has been described. 3. Thrombus susceptibility, measured by the thrombin test, increased with age and during cortisone treatment, and decreased after heparin injection and following large doses of whole body x-irradiation. 4. The thrombin susceptibility test could be correlated with the platelet count in x-irradiated hamsters, showing a relatively critical minimum concentration of blood platelets (100,000/cu.mm.) required for platelet thrombosis. 5. The relationship of platelet concentration to platelet thrombus formation and predisposition to hemorrhage has been discussed.