A STUDY OF POTASSIUM-OSMIUM-CYANIDE COMPLEX

APPLICATION TO ULTRASTRUCTURAL CYTOCHEMISTRY WITH DIAMINOBENZIDINE

Abstract

Potassium-osmium-cyanide complex (POCC) was substituted for osmium tetroxide procedures for the ultrastructural demonstration of cytochrome oxidase and peroxidase with diaminobenzidine (DAB).
POCC reacted with DAB polymer resulting from the oxidation reaction producing electron opaque deposits. POCC produced fine homogeneous staining and more contrast than did the usual osmication method. This suggests a means of making the methods more sensitive. Careful controls are necessary since POCC alone stains smooth membrane elements, thereby possibly obscuring true reaction products in some cases.