抄録
The authors studied on the role of factor VIII and platelet membrane glycoproteins implicated in ristocetin-induced platelet aggregation.
The residual levels of factor VIII procoagulant activity, factor VIII-like antigen and von Willebrand factor in plasma after aggregation of platelet-rich plasma by ristocetin (final concentration; 1.5mg/ml) were assayed. The level of factor VIII-like antigen was found to be significantly decreased and that of von Willebrand factor was slightly decreased, whereas there was no changes in factor VIII procoagulant activity.
The level of factor VIII-like antigen in plasma of patients with DIC was found to be markedly increased.
Analysis by SDS polyacrylamide gel electrophoresis of platelets treated with ristocetin revealed no remarkable changes in the distribution of membrane glycoproteins except that glycoprotein II was slightly reduced. Normal human washed platelets treated with low concentration of trypsin had reduced membrane glycoprotein I and did not respond in ristocetin-and bovine fibrinogen-induced platelet aggregation.
These data suggest that a small amount of factor VIII in plasma is utilized during ristocetin-induced platelet aggregation and that human factor VIII and platelet membrane glycoprotein I may play a functional role in ristocetin-induced platelet aggregation.
