The kinetics of vascular thermotolerance in SCK tumors of A/J mice.
Development of thermotolerance has been observed in diverse biological systems. Despite the important role of blood circulation in heat-induced tissue damage, little is known about vascular thermotolerance. The kinetics of vascular thermotolerance in SCK tumors of A/J mice was investigated in this study. A single heating at 43.5 degrees C or 44.5 degrees C for 1 hr caused marked damage in tumor vasculature, as demonstrated by a marked decrease in Rb-86 uptake (% of injected dose/g of dried tissue). The tumor vasculature became resistant or tolerant to subsequent heatings at those temperatures when the tumors were preheated at 42.5 degrees C for 1 hr. Vascular thermotolerance became significant at 5 hr and reached its maximum at 18 hr after preheating at 42.5 degrees C. When the vascular thermotolerance was at its peak, heating at temperatures as high as 44.5 degrees C for 1 hr could not reduce the tumor blood flow. The vascular thermotolerance decayed considerably but not completely at 72 hr after the preheating. The vascular thermotolerance may exert a profound implication on the response of tissues, including tumors, to multiple heatings.
University of Minnesota Medical School, Department of Therapeutic Radiology-Radiation Oncology, Minneapolis 55455.
C W
CW
Song
J C
JC
Lin
L M
LM
Chelstrom
S H
SH
Levitt
D000222:Adaptation, Physiological; D000818:Animals; D006979:Hyperthermia, Induced; D007700:Kinetics; D008297:Male; D051379:Mice; D008805:Mice, Inbred A; D008833:Microcirculation; D009374:Neoplasms, Experimental / Q000098:blood supply* / Q000628:therapy