Electron probe microanalysis of calcium and phosphorus in dense bodies isolated from human platelets

Electron probe microanalysis has been used to examine the calcium and phosphorous content of human platelet dense bodies in intact cells and following isolation. In both preparations, differences in the net X-ray counts for phosphorus were not significant, although the isolated dense bodies produced an average of 31% higher net calcium counts than those in intact cells. In addition, the size of the dense-body core in each of the two preparations was not significantly different. Thus, human-platelet dense bodies can apparently undergo biochemical isolation without appreciable loss of their calcium or phosphorus content, and critical examination of storage and transport in the isolated organelles may produce conclusions relevant to similar processes in the intact platelet.