Experimental Venous Thrombosis in the Rat

Summary

1. The effect of erythremia and thrombocythemia on thrombus formation has been examined in rats using a standardized operation on the jugular vein. In control animals the incidence of thrombosis was 30’% ( ± 4.6 S. E.).

2. Hypoxic induced erythremia increased the incidence of thrombosis (53% — p <C 0.05). The mean hematocrit value in this group was 62.

3. An increase in the thrombocyte count with 34%, produced by giving a thermostable human plasma fraction to normal rats, did not significantly increase the incidence of thrombosis (40%).

4. An increase in the thrombocyte count with 26% in erythremic animals increased the incidence of thrombosis nearly twice (56%, p <C 0.05).

5. The global tests for plasma coagulation, the fibrinogen levels and the antifibrinolytic activity of plasma were not significantly influenced by the conditions examined.

6. The number of adhesive platelets measured in vitro increased in the animals with erythremia.

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