Sensitivity of hyperthermia-treated human cells to killing by ultraviolet or gamma radiation

Journal Article · Fri Nov 01 04:00:00 EST 1985 · Radiat. Res.; (United States)

DOI:https://doi.org/10.2307/3576619· OSTI ID:5805234

Mitchel, R E; Smith, B P; Wheatly, N; Chan, A; Child, S; Paterson, M C

Human xeroderma pigmentosum (XP) or Fanconi anemia (FA) fibroblasts displayed shouldered 45/sup 0/C heat survival curves not significantly different from normal fibroblasts, a result similar to that previously found for ataxia telangiectasia (AT) cells, indicating heat resistance is not linked to either uv or low-LET ionizing radiation resistance. Hyperthermia (45/sup 0/C) sensitized normal and XP fibroblasts to killing by gamma radiation but failed to sensitize the cells to the lethal effects of 254 nm uv radiation. Thermal inhibition of repair of ionizing radiation lesions but not uv-induced lesions appears to contribute synergistically to cell death. The thermal enhancement ratio (TER) for the synergistic interaction of hyperthermia (45/sup 0/C, 30 min) and gamma radiation was significantly lower in one FA and two strains (TER = 1.7-1.8) than that reported previously for three normal strains (TER = 2.5-3.0). These XP and FA strains may be more gamma sensitive than normal human fibroblasts. Since hyperthermia treatment only slightly increases the gamma-radiation sensitivity of ataxia telangiectasia (AT) fibroblasts compared to normal strains, it is possible that the degree of thermal enhancement attainable reflects the genetically inherent ionizing radiation repair capacity of the cells. The data indicate that both repair inhibition and particular lesion types are required for lethal synergism between heat and radiation. We therefore postulate that the transient thermal inhibition of repair results in the conversion of gamma-induced lesions to irrepairable lethal damage, while uv-type damage can remain unaltered during this period.

• Research Organization: Atomic Energy of Canada Limited, Chalk River, Ontario
• OSTI ID: 5805234
• Journal Information: Radiat. Res.; (United States), Journal Name: Radiat. Res.; (United States); ISSN RAREA
• Country of Publication: United States
• Language: English

Related Subjects

560121* -- Radiation Effects on Cells-- External Source-- (-1987)
560201 -- Thermal Effects-- Cells-- (-1987)
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMAL CELLS
ANIMALS
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
BODY TEMPERATURE
CELL KILLING
DISEASES
ELECTROMAGNETIC RADIATION
GAMMA RADIATION
HYPERTHERMIA
IONIZING RADIATIONS
MAMMALS
MAN
PRIMATES
RADIATION EFFECTS
RADIATIONS
RADIOSENSITIVITY EFFECTS
SENSITIVITY
SKIN DISEASES
TEMPERATURE EFFECTS
ULTRAVIOLET RADIATION
VERTEBRATES
XERODERMA PIGMENTOSUM