Removal of extracellular materials by HCL-tween treatment

Glutaraldehyde-fixed tissues were treated with HCl and tween 20 to remove such extracellular materials as collagen fibers and basal laminae. In the HCl-treatment the collagen fibers were digested, while in the tween-treatment the basal laminae were removed. By this method the basal interdigitations of cells of the proximal tubule and the pericytes on th capillary wall were clearly demonstrable by scanning electron microscopy (SEM).