Staining of Paneth Cells with Best's Carmine After Methylation

When sections are methylated (cone. HC1, 0.8 ml in absolute methanol, 100 ml; at 58 C) prior to staining with Best's carmine, the granules of Paneth cells of man, rat and mouse stain a bright red, but they do not stain at all with this stain without prior methylation. With paraffin sections after neutral formalin fixation, the required 2-hr methylation did not prevent the staining of neutral mucosubstances and glycogen, but after methylation for 12 hr, these substances no longer stained although the reaction of the granules of Paneth cells became still more intense. The advantages of this staining technique are: (1) There is good contrast because the background stains faintly and, of the structures in the intestinal wall, only eosinophilic leukocytes and a part of the collagen fibrils stain in addition to the granules of Paneth cells. (2) The result is more reliable and the staining easier to perform than with the majority of other techniques, since no differentation is necessary. The method is especially suited for detecting Paneth cells in pathological conditions and in altered tissues or areas in which these cells are scanty.