The Photosensitivity of Chick-Embryo Cells Growing in Media Containing Certain Carcinogenic Substances

Abstract

When certain cancer-producing hydrocarbons were added to cultures of chick-embryo tissue, the cells developed photosensitivity to the electric light used for the study of cells in tissue cultures. The photo-dynamic action caused definite changes in the state of the cell protoplasm, which were often accompanied by inhibited cell division. This brought about a later occurrence of abnormalities of mitosis that duplicated many of the types of abnormal mitosis characteristic of malignant growths (Lewis and Lewis, 1932; Lewis and Strong, 1934). Method Four samples of hydrocarbons were used in these experiments: two of 1: 2: 5: 6-dibenzanthracene (one obtained from Dr. A. Grollman and one from Dr. H. B. Andervont), one of 1: 2-benzpyrene and one of methylcholanthrene (both obtained from Dr. G. O. Grey). The electric light was reflected from a W. Mazda 100 W. 115 V. round, frosted bulb covered with a green shade, the edge of which was placed against the stage of the microscope in such a manner as to shield the eyes of the observer from the glare. The light, reflected by the mirror of the microscope, served to illuminate the field under observation and the heat from the bulb kept the stage of the microscope at a temperature of 38° C.