Selective electronmicroscopical contrast of the ring canals joining germ cells by ethanolic phosphotungstic acid and uranyl-EDTA-lead

Differential staining of mucin granules from epoxy resin sections by a phosphotungstic acid-methyl green procedure

After treatment of epoxy resin semithin sections from glutaraldehyde fixed rat large intestine with 5% aqueous phosphotungstic acid (PTA), staining with unpurified 0.2% solutions of methyl green at 60 C for 5 min produces a color differentiation between mucin granules of goblet cells. Some mucin granules and the glycocalyx appear deep green while the remaining granules, luminal mucin and collagen fibers are pink. The known contamination of unpurified methyl green with crystal violet seems to be responsible for the pink staining reaction of the latter structures, which also present an orange-red fluorescence under green exciting light. Electron microscopic observations show selective contrast of mucin granules which appear with a different amount of PTA deposits. This procedure is useful to reveal the heterogeneity of mucin granules in light and electron microscopy.

Chronic intoxication by heroin; histopathological effects on seminiferous tubules

Seminiferous tubules from heroin abusers and from rats chronically intoxicated by heroin samples presented a striking reduction in the thickness of the germinal epithelium. Light and electron microscopical studies showed a considerable increase of lipids and phagosomes in Sertoli cells, disorganization of their junction complexes, detachment of immature germ cells which appeared free in the tubular lumen, and formation of giant multinucleate spermatids. These alterations point out that Sertoli cells could be the target element for the toxic effect of heroin samples on the seminiferous epithelium.