[The changes in alpha-granule membrane protein (GMP-140) on plasma membrane of platelets during cardiopulmonary...

The degree of activation and damage of platelets during various stages of cardiopulmonary bypass (CPB) was studied with monoclonal antibody SZ-51 specific for an alpha-granule membrane protein (GMP-140) on the surface of activated platelets. The number of platelets fell significantly at the commencement of CPB and reached the minimum at the end of CPB; GMP-140 molecules on the platelet surface increased significantly after the commencement of CPB and reached the peak between the ending of bypass and administration of protamine and returned to normal level at 2 hours postoperatively, however, the concentration of GMP-140 in plasma began increasing at the end of CPB and reached the peak at 2 hours postoperatively and became normal at 24 to 48 hours after operation. The results indicate that platelet activation and damaging occur during CPB.