[Ultrastructural changes in thrombocytes of patients with idiopathic thrombocytopenic purpura during the treatment with vincristine].

Electron-microscopic and electron-histochemical data have been presented on platelet ultrastructural shifts in patients with idiopathic thrombocytopenic purpura 1 h, 1, 4 and 8 days after one injection of vincristine. Vincristine induces depolymerization of microtubules+, appearance of crystalloid structures in platelet cytoplasm alters the biogenesis of lysosomal enzymes; for the first time the activity of acid phosphatase has been shown in cisterns of the dense tubular system. Electron-microscopic signs of thrombocytopoiesis stimulation are revealed on day 4 after the injection. The mechanism has been shown of platelet number growth. The duration of the effect of a single low dose of vincristine is eight days, that has been evidenced by the state of the microtube structure.