[Morphological changes of platelets in disturbed cerebral microcirculation--a clinical study using a scanning electron microscope (author's transl)].
Many factors are known that contribute to the pathogenesis of the cerebral microcirculatory disturbances, but, there are few reports investigating the roles of the intravascular components directly. The present study was undertaken to evaluate morphological changes of platelets in patients with cerebral damage, in relation to neurological signs, especially consciousness levels. Morphological changes of platelets were observed in 72 patients with intracranial organic lesions. These lesions included subarachnoid hemorrhages, hypertensive cerebral hemorrhages, cerebral infarctions, brain tumors, chronic subdural hematomas, and acute epidural hematomas. Two blood samples were taken, one from the internal jugular vein (the blood after cerebral perfusion), the other from the cubital vein (systemic blood). After fixative procedures with 1% glutaraldehyde, the differences in the three-dimensional structures of platelets were compared, using a scanning electron microscope. In general, remarkably activated forms of platelets were found in the blood after cerebral perfusion in cases with severely impaired consciousness in the acute stage. But, in cases without severe neurological deficits, such changes of platelet forms were rarely seen. A close relationship was suggested between the degree of neurological damage (especially consciousness levels) and that of platelet activation in the acute stage. In the chronic stage, these changes of platelets in the cerebral blood disappeared. Changes of platelet forms were not found in the systemic blood from the cubital vein, even in the acute stage. It is clinically suggested that morphological changes of platelets play an important role in the pathogenesis of the disturbed cerebral microcirculation. Obstruction of cerebral microvasculature may be caused, mechanically by the activated platelets themselves, and/or chemically by vasoconstrictive substances released from these platelets. Therefore, in the treatment of these intracranial organic lesions, it is concluded that the possible roles of activated platelets should be taken into consideration.
D000293:Adolescent; D000328:Adult; D000368:Aged; D001792:Blood Platelets / Q000648:ultrastructure*; D002561:Cerebrovascular Disorders / Q000097:blood*; D005260:Female; D006801:Humans; D008297:Male; D008577:Meningeal Neoplasms / Q000097:blood; D008579:Meningioma / Q000097:blood; D008833:Microcirculation; D008855:Microscopy, Electron, Scanning; D008875:Middle Aged; D013345:Subarachnoid Hemorrhage / Q000097:blood