EXPERIMENTAL EPIDERMAL METHYLCHOLANTHRENE CARCINOGENESIS IN MICE - 2ND SUMMARIZING REPORT

[摘要] The author briefly reviews observations of the response of the epidermis of mice to the carcinogen methylcholanthrene made during the period 1938-1942. The studies of the response to the carcinogen during the 1942-1945 period revealcd an increase in mitotic frequency in the epidermis 12 hrs. or more after an application with the greatest % frequency occurring in the spinous layer; earliest chromosome enlargement was found 48 hrs. after the application; a rise in the cytoplasmic ribonucleic acid followed by a partial recession; the alkaline phosphatase activity of the nuclei of basal cells is in the reticular layer increased greatly and equally in papillomata and carcinomata; a new equilibrium is established in the mg. cholesterol/gm. protein ratio; the number of mast cells increased with the epidermal hyperplasia reaching a maximum just before cancer developed after which it was sharply reduced in the cancer; certain mineral ratio disturbances during the precancerous hyperplasia, and the sebaceous glands appear to be protective against the carcinogen.