Takuo Yokose

Filterability and the Shape of Platelets: The Effect of Stimulant

Hemorheological studies on the cellular component of blood have hitherto centered on erythrocytes and leukocytes. However, all possible factors affecting the flow behavior of whole blood should be considered to improve our understanding as to the pathophysiology of microcirculation in various diseases. For example, the shape of platelets has been proved to be changed from discoid to spheroid in the presence of platelet aggregation inducers, such as ADP [1, 4]. This morphological change, which occurs at the initial stage of platelet aggregation, also deserves rheological consideration. The present study was performed in search of the optimal conditions under which the in vitro filterability of platelets will reflect their in vivo flexibility in microcirculation. The varying clinical significance of platelet filterability in accordance with the change in their shape will also be discussed.

Ionized Free Calcium Concentration and Deformability in Platelets

Platelets may play an important role in the pathogenesis of cerebral infarction in many ways, for example by forming occlusive thrombi and by releasing vasoconstrictor substances such as serotonin and thromboxane A2 (TXA2). It has been found that the platelet function in thrombotic disease is exacerbated, and the significance of this finding is being debated [2, 7].