The influence of embedding media and fixation on the postembedment ultrastructural demonstration of complex carbohydrates. III. High iron diamine staining for sulfated glycoconjugates.

The high iron diamine (HID) method for detection of sulfated complex carbohydrate has been applied directly on thin sections of variably fixed tissues embedded in epoxy and nonepoxy resins. Results with postembedment HID staining in mouse intestinal epithelium are compared to those previously obtained using preembedment methods. Sections from epoxy-embedded tissues have been found to exhibit the weakest staining intensity. Intense, specific staining was obtained in tissues not postfixed with osmium tetroxide and embedded in polystyrene, polyester resins, styrene-methacrylate, and especially the styrene-Vestopal W embedding mixture. Postosmication of tissues abolished HID staining in epoxy resins and the styrene-Spurr's resin embedding mixture, but only reduced the staining intensity in tissues embedded in nonepoxy resins.