Effects of a second heating on blood flow in tumors.
The blood flow in RIF-1 tumors of C3H mice, as measured with the 86Rb uptake method, declined markedly after a single heating at 43.5 degrees C or 44.5 degrees C for 1 h. However, preheating at 42.5 degrees C for 1 h significantly lessened the decrease in tumor blood flow caused by subsequent heating at 43.5 degrees C or 44.5 degrees C for 1 h. Such an influence of preheating on the effect of reheating in decreasing the tumor blood flow was significant as early as 6 h after the preheating, peaked at 36 h, and then decayed the following 2-3 days. In fact, a reheating at 43.5 degrees C for 1 h applied 36 h after a preheating at 42.5 degrees C for 1 h resulted in an increase rather than a decrease in blood flow. The cause of such a profound impact of preheating on the effect of reheating on the blood flow is unclear. However, circumstantial evidence including the histopathological appearance of tumors suggests that thermotolerance is induced in the blood vessels of the tumor as a result of preheating.
Song
C W
CW
University of Minnesota Medical School, Department of Therapeutic Radiology-Radiation Oncology, Minneapolis.
Chelstrom
L M
LM
Sung
J H
JH
D000818:Animals; D001783:Blood Flow Velocity; D002460:Cell Line; D006614:Hindlimb; D006979:Hyperthermia, Induced; D051379:Mice; D008809:Mice, Inbred C3H; D009368:Neoplasm Transplantation; D009369:Neoplasms / Q000098:blood supply; D012212:Rheology; D012414:Rubidium Radioisotopes; D013696:Temperature; D013997:Time Factors
D012414:Rubidium Radioisotopes