[Inhibition of cancer cell stickiness, a model for the testing of in vivo thrombocyte aggregation inhibitors. IV. Effect of sulfinpyrazone].

It has been shown that sulfinpyrazone is able to interfere with the dynamic interaction between sticky Walker-256-carcinosarcoma cells and the vascular endothelium. This effect is due to a dose-dependent inhibition of platelet adhesiveness and aggregation to sticky circulating tumor cells and their consequent attachment to the vascular endothelium as observed by means of intravital capillary microscopy in the mesentery of rats. Further proof of these investigations was that sulfinpyrazone led to a dose-dependent inhibition of the immediate drop of circulating platelets and reduced significantly the lethal pulmonary tumor cell embolism which occurred in 57.5% of the controls within 5-10 minutes after intravenous transplantation of 1 X 10(6) Walker-256-carcinosarcoma cells. These results are interpreted in an inhibition of platelet adhesiveness and aggregation in vivo by sulfinpyrazone.