Sheet preparations of the stratum granulosum from mammalian skin and oral epithelium.

Acetic acid has been used to obtain sheet preparations of the stratum granulosum from epidermis and oral epithelium of mouse, rat, hamster and man. Clear differences exist in the appearance of nuclei and keratohyalin granules and in the extent of cell overlapping. In the ventral surface of mouse tongue, the number of granular cells in a sheet preparation is relatively constant (average +/- S.D. = 1633 +/- 160/mm2). Cell suspensions show a greater variation in the area and maximum diameter of the cells in ventral tongue compared to mouse ear epidermis. As might be expected, this is reflected in the pattern of stacking of suprabasal cells into discrete columns in ear, but not in ventral tongue epithelium. The ratio of granular to basal cells for different sites and species is fairly constant, with an average of approximately 10:1. The pattern of nuclear breakdown can be followed, beginning in the middle of the nucleus and gradually extending outwards, often in an irregular manner until the entire nucleus is removed.