The Effects of Elevated Temperature on Carcinogenesis.
Ohio State University, Columbus, Ohio :19 pages
To study the effects of elevated temperatures on carcinogenesis, 7 to 9 week old C3H-mice maintained at either 23 or 30 degrees-C were divided into four groups: a no treatment control; high level carcinogen, 2.0 milligrams/week (mg/wk) benzo(a)pyrene (50328) (B(a)P); low level carcinogen, 0.2mg/wk B(a)P; and vehicle (toluene). Tumors appeared suddenly at the fifth week of treatment and in large numbers in the high dose group with the warmer climate group experiencing the greater incidence rate and possessing tumors of larger size. At the low dose level, tumors also occurred at the fifth week but much more gradually; a lower incidence of tumors was noted at 30 degrees-C as the trial progressed and became significant by the 24th week. Tumors occurring in the low dose group were also smaller in size. Control and vehicle control groups showed no evidence of skin tumors at any time or either temperature. Survival in the high dose treatment group decreased significantly between week 12 and week 14, with 50 percent survival noted by 22 weeks. No temperature effects were noted on survival in this group. Excessive mortality at the low level dosages occurred at 22 to 24 weeks and 50 percent survival was noted at week 36 at 23 degrees and at week 41 at 30 degrees, a significant difference. The tumors found were all squamous cell carcinomas which metastasized generally to the lungs. The authors conclude that the potentially beneficial effects noted for warmer temperatures on B(a)P carcinogenicity may be useful when applied to the activity of other carcinogens.
NIOSH-Contract; Contract-210-76-0132; Laboratory-animals; Carcinogenesis; Polycyclic-hydrocarbons; Pyrenes; Temperature-effects;
NTIS Accession No.
Ohio State University, Columbus, Ohio