[Thermal sensitivity of Ehrlich ascites cancer cells forming colonies in agar cultures in diffusion chambers]

Thermosensitivity of clonogenic ascites Ehrlich carcinoma cells (AEC), forming colonies in agar cultures in diffusion chambers was studied when heating them in vitro at 41-44 degrees C. The clonogenic cells of AEC are shown not to essentially differ both in the colony-forming efficiency (CFE) and in the proliferative status on the 3rd and 7th days. No essential differences are revealed in thermosensitivity of such cells. The heating time-survival curves are exponential or S-shaped with a small "shoulder". The temperature increase by 1 degree C resulted in a 2-2.5-fold decrease in the time of effective hyperthermia treatment. The values of D0 for cells treated with 42 degrees C in different experiments varied from 20.1 min to 24.6 min. Only one type of thermal damage reaction with the energy of inactivation about 150 kcal/M was observed in AEC cells in the temperature range studied.