The effect of mitomycin C on developing chicken embryos.

The mitomycins were isolated from the broth of Streptomyces caespitosus by Hata, Shimada & Ishu (1957). Mitomycin C, one of a series of chemically related substances, has been most frequently used in experimental and clinical studies. It was found to have a marked antibacterial, antiviral and antitumor activity in animals and man. In humans, mitomycin C has been used with varying success in the palliative treatment of osteogenic sarcoma, carcinoma of stomach, chronic myelogenous leukemia, reticulum cell sarcoma and other malignancies (Cancer Chemotherapy. Rep., 1959; Frank & Osterberg, 1960; Evans, 1961). The teratogenic activity of mitomycin C has been only briefly noted (Yamura, 1961; Takaya, 1965). The purpose of these experiments is to study the effects of mitomycin C in chicken embryos after yolk-sac injection during an early period of development. To study the teratogenic activity of drugs in chicken embryos, the optimal times of yolk-sac injection are the 3rd and 4th days of development. If the drugs are injected during the first 48 h of development, the teratogenic and lethal doses are so similar that the embryos usually die shortly after injection. By the 3rd and 4th days, however, when development is more advanced, but still in the active phase of organogenesis, a number of affected embryos may survive longer or until hatching. By the end of the 4th day the organ systems are well established; although the action of many drugs can be demonstrated up to the 8th day of development or later, the chances of producing malformations are reduced.