[Cytochemical study of Mg2(+)-ATPase and ALPase activity in human meningiomas]

Ultracytochemical features of microvessels and tumor cells of the human meningiomas were examined by light and electron microscopy with special reference to the distribution of Mg2(+)-ATPase and alkaline phosphatase (ALPase) activity on the walls of the vessels and tumor cell surfaces. Materials used were 4 cases of meningiomas, 2 of which were meningotheliomatous type, one fibroblastic type and one malignant meningioma respectively. For ultracytochemistry, specimens were quickly fixed in an ice-cold 0.1 M cacodylate buffer containing 8% sucrose (pH 7.2) for one hour and transferred to a substrate solution for detection of Mg2(+)-ATPase and ALPase. The preparations were incubated at 37 degrees C for 15-30 min in the medium described by Mayahara et al. for ALPase and for 15-20 min in the medium described by Wachstein and Meisel. The control samples were incubated in a medium containing 1 mM Bromotetramisole for ALPase and also in a substrate free medium for Mg2(+)-ATPase. At the light microscopy, Mg2(+)-ATPase and ALPase activities appeared to be mainly restricted to the capillary wall and around or in the tumor cell nest showing whorl formation. Both enzyme activities were negative in the control study. By electron microscopy, reaction products representing Mg2(+)-ATPase activity were distributed in the basolateral plasma membrane of the endothelial cells on the surface of the pericytes and on the surface of the tumor cells. Reaction products of ALPase activity located mainly on the abluminal surfaces of the endothelial cells and in some specimen on both luminal and abluminal surfaces of those cells. Intense reaction products were distributed evenly on all round surfaces of the tumor cells.(ABSTRACT TRUNCATED AT 250 WORDS)