Hyperthermic radiosensitization of synchronous Chinese hamster cells: relationship between lethality and chromosomal aberrations. [X rays]

Journal Article · Sun Oct 01 04:00:00 EDT 1978 · Radiat. Res.; (United States)

DOI:https://doi.org/10.2307/3574926· OSTI ID:6801905

Dewey, W C; Sapareto, S A; Betten, D A

Synchronous Chinese hamster cells in vitro were obtained by mitotic selection. The cells were heated at 45.5/sup 0/C for 4 min in mitosis, 11 min in G/sub 1/, or 7 min in S sphase and then x-irradiated immediately thereafter. Colony survival from heat alone was 0.30 to 0.45, and the frequency of chromosomal aberrations induced by heat was 0.00, 0.14, or 0.97 for heat treatments during M, G/sub 1/, or S, respectively. As shown previously, lethality from hyperthermia alone is due to chromosomal aberrations only when the cells are heated during S phase. The log survival (D/sub 0//sup approximately/ = 80 rad) and aberration frequency curves for cells irradiated during mitosis were linear, and the only effect of hyperthermia was to shift the curves in accord with the effect from heat alone. Thus, hyperthermia did not radiosensitize the mitotic cells. The cells irradiated in G/sub 1/ were more resistant (D/sub 0//sup approximately/ = 100 rad) than those irradiated in mitosis, and the survival and aberration frequency curves both had shoulders. The primary effect of hyperthermia was to greatly reduce the shoulders of the curves and to increase the slopes by about 23%. The cells irradiated in S were the most resistant (D/sub 0//sup approximately/ = 140 rad), and the survival and aberration frequency curves both had large shoulders. For both end points of lethality and chromosomal aberrations, heat selectively radiosensitized S-phase cells relative to G/sub 1/ cells by removing most of the shoulder and increasing the slope by about 45%. For cells treated in G/sub 1/ or S, the increase in radiosensitization following hyperthermia can be accounted for by an increase in the frequency of chromosomal aberrations.

• Research Organization: Colorado State Univ., Fort Collins
• OSTI ID: 6801905
• Journal Information: Radiat. Res.; (United States), Journal Name: Radiat. Res.; (United States) Vol. 76:1; 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 CULTURES
CELL CYCLE
CELL KILLING
CHROMOSOMAL ABERRATIONS
CHROMOSOMES
CORRELATIONS
ELECTROMAGNETIC RADIATION
HAMSTERS
HYPERTHERMIA
IONIZING RADIATIONS
IRRADIATION
MAMMALS
MUTATIONS
RADIATION EFFECTS
RADIATIONS
RADIOINDUCTION
RADIOSENSITIVITY
RADIOSENSITIVITY EFFECTS
RODENTS
SURVIVAL TIME
SYNCHRONOUS CULTURES
VERTEBRATES
X RADIATION