topical treatment of hairless hamster skin with crude coal tar has been shown to induce epidermal thickening , an increased labelling index in the basal cell layer , an elevation in nadp-dependent glucose-6-phosphate dehydrogenase activity throughout the epidermis , an increased squame count , comedo formation , and atrophy of the sebaceous glands .
C0221925
basal cell
C0014520
epidermis