HID-AB2.5-PAS and HID-PAS methods for the histochemical analyses of a variety of carbohydrates.

The high iron diamine (HID) staining procedure was combined with alcian blue pH 2.5 (AB2.5) and periodic acid-Schiff (PAS) methods for the simultaneous demonstration of carbohydrates containing sulfate esters, carboxyl groups and oxidizable vicinal diols, whereas it was sequentially employed with PAS alone to differentiate sulfate esters from oxidizable vicinal diols. A variety of rat tissues and the epidermis of four fish species were utilized to test the specificity or selectivity of these methods. The HID-AB2.5-PAS sequence largely coloured carbohydrates containing sulfate esters, carboxyl groups and oxidizable vicinal diols in brownish black, turquoise and magenta shades respectively. The HID-PAS sequence coloured sulfate esters brownish black and oxidizable vicinal diols magenta. On the basis of the experimental and control studies on the both staining techniques, these staining methods could be postulated to represent efficient and useful techniques for precise histochemical analyses and simultaneous differentiations of a variety of carbohydrates in light microscopy.