Mepacrine labelling test and uranaffin cytochemical reaction in human megakaryocytes
Hourdillé, P.; Fialon, P.; Belloc, F.; Boisseau, M.R.; Andrieu, J.M.
Thrombosis and Haemostasis 47(3): 232-235
1982
ISSN/ISBN: 0340-6245 PMID: 7112496 Document Number: 191934
5-HT [5-hydroxytryptamine] storage organelles were observed by EM analysis in human megakaryocytes. They were less numerous per unit of surface than in platelets. Their number depended on the visualization technique employed. Thus, after fixation with Ca-enriched glutaraldehyde, a higher number of very opaque organelles was observed than of uranaffin-positive organelles after the cytochemical uranaffin reaction. With conventional EM deep black granules characteristic of dense bodies were not observed. Fluorescent microscopy showed greenish yellow granules distributed throughout the whole cytoplasm in 96 .+-. 1.4% of normal megacaryocytes incubated with mepacrie. In 85.6 .+-. 5%, 5.28 .+-. 1.28 granules/10 .mu.m2 were observed. With the mepacrine labeling test, 74% of the megakaryocytes of a patient with Hermansky-Pudlak syndrome contained no granules. A similar finding was made in the platelets of the same patient. Mepacrine also stains the dense bodies in the megakaryocytes and in the Hermansky-Pudlak syndrome the platelet anomaly is apparently secondary to a megakaryocyte anomaly.