Thermotolerance in human glioma cells

Human glioma cells held in plateau phase were tested for the development of chronic and acute thermotolerance. Long duration, mild hyperthermia at 39-42 degrees C for up to 48 h showed no development of chronic thermotolerance. Heating at 45 degrees C immediately after mild hyperthermia showed that acute thermotolerance did develop for 40-42 degrees C heating. This thermotolerance developed at about the same rate for the three inducing temperatures (40-42 degrees C) but the decay characteristics were temperature dependent. In fact, for 42 degrees C heating thermosensitization to subsequent 45 degrees C heating was achieved after 48 h of heating. These data show that chronic and acute thermotolerance may be different in human glioma cells.