Ultrastructure of human leukocytes after simultaneous fixation with glutaraldehyde and osmium tetroxide and "postfixation" in uranyl acetate.

Human leukocytes in suspension or in monolayer cultures have been processed for electron microscopy by fixation in a freshly made cold mixture of glutaraldehyde and osmium tetroxide and by "postfixation" in uranyl acetate. Simultaneous exposure to glutaraldehyde and osmium tetroxide eliminates many of the shortcomings seen when either of these agents is used alone as the initial fixative. Specimens are processed to the stage of dehydration as single cell suspensions or as very small clumps to assure rapid penetration of fixatives and efficient washing. The technique is rapid and reproducible. Electron micrographs presented in this report illustrate the ultrastructural features of human white cells prepared by this method.