A Study on Some Problems in PFAAB-PAS-OG Staining Method

Abstract

The most critical and imporant step in PFAAB-PAS-OG staining method is the oxidation in the strong acidic solution. Although alternative oxidants such as peracetic acids, periodic acids and acid perrnanganate could be employed instead of performic acid, many investigators prefer the latter because of its better staining results. Since performic acid is made of formic acid, cone. sulfuric acid and hydrogen peroxide, it makes the tissue swollen unfortunately and finally let the sections come off the slide. Celloidin, which have been used as an embedding media, have good physical and chemical character in many respects. One of them is the fact that celloidin passes staining dyes and other chemical solutions easily without disturbing the effect of the solutions. In our experiments, some mucoid cells were oxidized across the celloidin film and appeared as alcian blue stained blue granules, while the remains which were intact to the oxidants and which contains either no cystine or an insufficient amount of cystine to give a positive alcian blue reaction appeared as PAS-positive magenta granules. With the alcian blue stain, celloidin has been colored as deep blue and the color was remained even after 24 hours rinsing in the running tap water, or in the acidic solutions. To overcome the difficulties of oxidation step in PFAAB-PAS-OG reaction, tissue sections were coated with celloidin film before immersing in acidic solution and obtained good staining results.