Demonstration of Alkaline Phosphatase in Gross Specimens of Small Intestine

Abstract

The Burstone azo-dye coupling technique for the demonstration of alkaline phosphatase has been applied successfully to gross specimens of small intestine. Guts are opened and washed in cold saline; fixed 2 hr or longer in cold 10% saline-formol, 10% Ca-formol, or 10% neutral formalin; washed in cold distilled water and Tris-HCl buffer (pH 8.6); incubated for 20 min or longer in Burstone medium (Enzyme Histochemistry, 1962) containing naphtol AS-MX phosphate and red violet LB salt; washed in water and stored in formalin. After incubation, tissues fixed for 18 hr or more may be embedded in paraffin, cut and stained for routine histologic study. Regions of the intestine that have alkaline phosphatase activity in the striated border are stained red, with an intensity proportional to the enzymatic activity present. Lesions in the mucosa usually show light staining or none. The distribution of alkaline phosphatase activity as revealed by gross staining has been confirmed by the study of representative fresh frozen sections stained in the same medium. Staining in toto is recommended to demonstrate variations of the activity of alkaline phosphatase in large specimens either normal or pathologic, and to facilitate recognition and photography of even small lesions in pathologic guts.