Induction during G1 of heat radiosensitization in Chinese hamster ovary cells following single and fractionated heat doses

Journal Article · Tue Jun 01 04:00:00 EDT 1982 · NIDA Res. Monogr.; (United States)

OSTI ID:6220811

Holahan, E V; Highfield, D P; Dewey, W C

When G1 Chinese hamster ovary cells were heated at 42.2 degrees C and X-irradiated, heat radiosensitization increased slightly with cell killing. However, when thermo-tolerance was allowed to develop by continuous heating for periods longer than 4 hours, which reduces survival to 0.18, heat radiosensitization no longer increased with continued heating or cell killing. When cells were heated with single doses at 45.5 degrees C, heat radiosensitization increased as a function of heat killing. However, if acute heat doses at 45.5 degrees C were fractionated and cells incubated for 10 hours at 37 degrees C between fractions, significant tolerance to heat radiosensitization was observed. For example, heating cells at 45.5 degrees C for 15 minutes reduced survival to 0.40 and decreased the D0 to 0.45 gray, whereas 2 fractionated 15-minute doses at 45.5 degrees C, separated by 10 hours at 37 degrees C, resulted in a D0 of 0.65 gray. Thus if heat killing increased without the development of thermotolerance, heat radiosensitization also increased continually, whereas when thermotolerance developed after continuous or fractionated heating without cell progression, some tolerance to continued heat radiosensitization also was observed. This tolerance to both heat killing and heat radiosensitization indicates that both involve similar target(s).

• Research Organization: Department of Radiology and Radiation Biology, Colorado State University, Ft. Collins
• OSTI ID: 6220811
• Journal Information: NIDA Res. Monogr.; (United States), Journal Name: NIDA Res. Monogr.; (United States) Vol. 61; ISSN MIDAD
• 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
ANIMALS
BODY
BODY TEMPERATURE
CELL CULTURES
COMPARATIVE EVALUATIONS
DOSE-RESPONSE RELATIONSHIPS
DOSES
ELECTROMAGNETIC RADIATION
FEMALE GENITALS
FRACTIONATED IRRADIATION
GONADS
HAMSTERS
HYPERTHERMIA
IONIZING RADIATIONS
IRRADIATION
MAMMALS
NORTH AMERICA
ORGANS
OVARIES
RADIATION DOSES
RADIATIONS
RADIOSENSITIVITY
RADIOSENSITIVITY EFFECTS
RESPONSE MODIFYING FACTORS
RODENTS
SURVIVAL CURVES
TEMPERATURE DEPENDENCE
TOLERANCE
USA
VERTEBRATES
X RADIATION