[Ultrastructural studies on the effect of roentgen rays and quinacrine (atebrin)--alone or in combination--on Ehrlich ascites tumor cells in monolayer culture].

Already two days after an X-ray irradiation with 8 Gy performed during the phase of exponential growth, the cells of an Ehrlich ascitic carcinoma in monolayer culture showed remarkable ultrastructural modifications, e.g. a markedly vacuolized endoplasmic reticulum, swollen mitochondria, increase of lysosome-like structures, and a decrease of microvilli in number and size. Ehrlich ascitic carcinoma cells submitted to an X-ray irradiation with 8 Gy and subsequently incubated with quinacrine (Atebrin) in a concentration of 4 x 10(-6) M, which alone had no significant effects on growth or ultrastructure, showed severe cellular lesions. The endoplasmic reticulum was still more vacuolized, the mitochondria were severely damaged, lysosome-like structures and residual bodies were increased, and the cellular surfaces had still less microvilli. Microtubules and microfilaments, however, seemed rather increased. The effects of quinacrine (Atebrin) on cells exposed to X-rays were discussed with respect to the known inhibiting action of this substance on DNA synthesis, especially with regard to DNA reparation. The modifications of the microtubule-microfilament system could be correlated to increased intracellular digestive processes involved in the catabolism of radiodamaged structures.