Fine Structure of Cerebral Fluid Accumulation

I Introduction NTRACEREBRALimplants of cryptococcal or pneumococcal polysaccharides caused intense vacuolation in white matter.1Light microscopic and immunofluorescent studies indicated that the polysaccharides spread in white matter for considerable distances.1,2In the late stage, the vacuoles were clearly intracellular, and the same location was erroneously inferred for the early stage.1Electronmicroscopic studies of the early stage proved that the vacuoles actually constituted greatly distended extracellular spaces filled with polysaccharide-rich fluid.3Only small amounts of fluid entered cells, either by direct invasion through ruptured cell walls (only in the neighborhood of the implant), or by engulfment in relatively rare phagocytes.4The present work is an electron microscopic study of the subacute and chronic phases of the experiment, phases in which the bulk of the fluid and foreign polysaccharide leave the extracellular spaces to become intracellular. In this work, we focus attention on the oligodendrocyte. Materials