The British Journal of Radiology, Vol 52, Issue 620 657-662, Copyright © 1979 by British Institute of Radiology

ARTICLES

The effect of local hyperthermia on the small intestine of the mouse

SP Hume, JC Marigold and SB Field

Small loops of mouse jejunum were exteriorized and heated by immersion in a bath of Krebs-Ringer salt solution. Crypts were lost in the heated regions with a half-time of approximately six hours and reached a steady level of damage by 10--16 hours. There was no recovery in crypt number for one week after hyperthermia. Using a 24 hour assay, crypt survival curves were obtained using various heating times in the temperature range 37.5 degrees C--44.5 degrees C. These curves were qualitatively similar to those resulting from radiation damage, showing a shoulder followed by exponential killing. As the temperature was increased, progressive changes in shape of the curves indicated a proportional inhibition of accumulation of sublethal heat damage combined with increased rate of expression of lethal damage. Over the temperature range 42.3 degrees C--44.5 degrees C, a linear relationship was found between the rate of crypt loss and the reciprocal of the absolute temperature. An activation energy of 600 +/- 70 kJ mole-1 was calculated using the Arrhenius equation. In this temperature range, doubling the heating time had the same effect as increasing the temperature by 1 degree C. At temperatures below about 42.3 degrees C, the tissue became relatively less sensitive to increasing the treatment time.