A new histochemical method for detection of sialic acids using a physical development procedure.

We have established an efficient histochemical method for demonstration of sialic acids in light microscopy. The method consists of a selective periodate oxidation-phenylhydrazine blockade and a thiocarbohydrazide-silver protein sequence followed by a physical development procedure. From the results obtained by the present experimental and control studies in tissue sections from a series of rat and mouse organs, such as stomach, duodenum, colon, liver, sublingual gland, lung, and kidney, the specificity and sensitivity of the method were sufficient. In the tissues tested, sialic acids were visualized as distinct brownish and blackish reaction products. Comparisons of the new method with the periodic acid-phenylhydrazine-Schiff (PA-P-S) or selective periodate oxidation-Schiff (PA*-S) method employed hitherto have confirmed that the new method reported here is higher in efficiency and visibility of reaction products than the latter two methods.