Blocking of lead tetraacetate-Schiff reactions in tissue sections by boric acid.

Abstract

CURRENT histochemical techniques for carbohydrates depend on the fact that many of these substances possess groupings capable of being oxidized to yield aldehyde residues, which can then be made visible with Schiff's reagent. Glegg, Clermont and Leblond1 showed that when lead tetraacetate (in glacial acetic acid) replaced periodic acid as the oxi-dant, the histological distribution of the reaction with Schiff's reagent was similar although the intensity at some sites differed. If this difference in the intensity of the Schiff reactions were due to preferential oxidation of cis α-glycol groupings by lead tetraacetate2, then boric acid, which readily complexes with cis-hydroxyl groups (for example, in carbohydrates)3, might be expected to block the oxidation of such groups and thus modify the subsequent Schiff reaction.