[Demonstration of an alkali PAS-effect using periodic acid at low concentration (author's transl)].

It has been shown that an isolated KOH PAS-effect of epithelial mucosubstances in the colonic mucosae of the rat can be demonstrated also without the conventionally used preliminary oxidation/reduction step. The method is based on the use of strongly diluted periodic acid after previous treatment of tissue sections with ethanolic KOH. As the positive reacting material has been proven to be sensitive against treatment with neuraminidase the modified KOH PAS-reaction should be related to the presence of acylated sialic acid residues in mucosubstances of the colonic mucosae of the rat.