Interaction of hyperthermia and radiation in CHO cells: recovery kinetics

Journal Article · Tue Jun 01 04:00:00 EDT 1976 · Radiat. Res.; (United States)

DOI:https://doi.org/10.2307/3574455· OSTI ID:7356537

Henle, K J; Leeper, D B

The sensitivity to hyperthermic damage (45/sup 0/C +- 0.05/sup 0/) and the interaction of hyperthermic damage with radiation damage was determined in Chinese hamster ovary (CHO) fibroblasts in monolayer culture. The survival curve for asynchronous cells heated at 45/sup 0/C was exponential with a shoulder (D/sub 0/ = 3.6 min, D/sub q/ = 7.5 min, n = 7.3). Recovery of the capacity to accumulate sublethal damage (return of extrapolation number to 7.3) was complete and occurred within the first 4 hr. By 72 hr the D/sub 0/ returned to normal although the D/sub q/ persisted at 20 min at 45/sup 0/C. Heating (17.5 min at 45/sup 0/C) followed immediately by radiation (450 rad) or radiation followed immediately by heating did not produce significantly different survival values. Hyperthermia reduced the D/sub 0/ of the radiation--survival curve by a factor of 1.9 and increased the extrapolation number by a factor of 3. The D/sub q/ remained unchanged. For intervals up to 48 hr, prior hyperthermia increased the extrapolation number and D/sub q/ of the radiation--survival curve to approximately 1000 and 650 rad, respectively. However, the D/sub 0/ remained unchanged at approximately 83 rad over the entire interval of 0 to 72 hr. For the sequence of radiation followed by hyperthermia, the D/sub q/ of the hyperthermia--survival curve was reduced to 2.9 min at 45/sup 0/C by simultaneous irradiation but returned to near-normal values after a fractionation interval of 2 hr. The D/sub 0/ of the hyperthermia--survival curve was unaffected by prior irradiation.

• Research Organization: Thomas Jefferson Univ., Philadelphia
• OSTI ID: 7356537
• Journal Information: Radiat. Res.; (United States), Journal Name: Radiat. Res.; (United States) Vol. 66:3; ISSN RAREA
• Country of Publication: United States
• Language: English

Related Subjects

560121* -- Radiation Effects on Cells-- External Source-- (-1987)
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMAL CELLS
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
BIOLOGICAL RECOVERY
CELL CULTURES
ELECTROMAGNETIC RADIATION
HEAT TREATMENTS
IONIZING RADIATIONS
IRRADIATION
RADIATION EFFECTS
RADIATIONS
RADIOSENSITIVITY EFFECTS
RECOVERY
SURVIVAL CURVES
SURVIVAL TIME
X RADIATION