Effect of hyperthermia on vascular functions of normal tissues and experimental tumors; brief communication.

The effect of hyperthermia on vascular volume and vascular permeability of the Walker carcinoma 256, skin, and muscle of inbred SD male rats was investigated. Whereas heating at 43 degrees C for 1 hour induced a significant increase in the functional vascular volume and vascular permeability in the skin and muscle, it did not change these vascular functions in the tumors. The increased vascular volume in the normal tissues suggested an increased circulation, which may enhance the dissipation of heat and result in a differential effect of hyperthermia on normal tissues and tumors.