CHANGES OF PLATELET CYTOSKELETAL PROTEINS FOLLOWING PLATELET-AGGREGATION INDUCED BY COLLAGEN AND PLATELET MEMBRANE GLYCOPROTEIN IN JAPANESEBLACK CATTLE WITH DELTA-STORAGE POOL DEFICIENCY

Five Japanese Black cattle showing the tendency of persistent hemorrha ge were diagnosed as delta-storage pool deficiency because of lack of dense bodies in platelets. There was no significant difference in the platelet count, fibrinogen concentration, prothrombin time and activat ed partial thromboplastin time between the cases and normal control ca ttle. However, the maximum platelet aggregation rate and the values of myosin in the cytoskeletons during platelet aggregation induced by co llagen were significantly lower in the cases compared with those in no rmal control cattle. The quantities of platelet membrane glycoprotein were in the range of 94-160 kDa and were not different between the cas es and control cattle. However, a decrease of thrombospondin in alpha- granules in platelet cytoplasm were suspected in two of the 5 cases.