Timed acid bath effects on kidney podocytes prepared for scanning electron microscopy.

In perfusion fixation of dog kidney glomeruli, observation of tear fractured surfaces by scanning electron microscopy reveals the deposition of "debris" on the surface of glomerular visceral epithelium (podocytes) that is not deposited on other kidney tissue surfaces. It is of concern to remove this debris without damage to tissue surfaces. A 5 minute bath in 8N HCl (hydrochloric acid) following postfixation in 1% OsO4 (osmium tetroxide) removes only some of the debris. A 10 minute acid bath removes this debris without visible damage to podocyte surface structures such as cilia, plicae or blebs. A 20 minute acid bath is destructive to these surface features.