Effect of pH on hyperthermic and x ray induced cell killing

Journal Article · Sun Feb 01 04:00:00 EST 1981 · Int. J. Radiat. Oncol., Biol. Phys.; (United States)

DOI:https://doi.org/10.1016/0360-3016(81)90439-9· OSTI ID:6525917

Freeman, M L ^[1]; Holahan, E V; Highfield, D P; Raaphorst, G P; Spiro, I J; Dewey, W C

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1. Columbia Univ., New York, NY

Chinese hamster ovary cells in vitro were heated (42.5/sup 0/C) before, during, or after X-irradiation (5 Gy). First, a slight degree of radioprotection was observed when cells were irradiated in acidic medium compared to irradiation in alkaline medium; i.e., 10 Gy reduced survival to 0.0035 at pH 6.75 compared to 0.0010 at pH 7.45. Second, survival increased independent of pH as the time between irradiation and subsequent heat treatment was increased. Third, both heat treatments alone and combined heat and irradiation treatments in acidic medium produced more cell killing than treatments in alkaline medium; the amount of recovery from heat damage which subsequently interacted with radiation damage decreased as the pH was decreased from 7.40 to 6.70. Furthermore, inhibition of recovery was reflected primarily as an increase in the slope of the radiation survival curve; i.e., heating for 60 min 150 min before irradiation decreased the D/sub 0/ from 1.00 Gy for cells heated and irradiated under alkaline conditions and to 0.70 Gy for cells treated under acidic conditions. The extrapolation numbers were 5 and 6 for the respective curves.

• OSTI ID: 6525917
• Journal Information: Int. J. Radiat. Oncol., Biol. Phys.; (United States), Journal Name: Int. J. Radiat. Oncol., Biol. Phys.; (United States) Vol. 7:2; ISSN IOBPD
• 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 TEMPERATURE
CELL CULTURES
CELL KILLING
DATA
DOSES
ELECTROMAGNETIC RADIATION
EXPERIMENTAL DATA
HAMSTERS
HYPERTHERMIA
INFORMATION
IONIZING RADIATIONS
MAMMALS
NUMERICAL DATA
PH VALUE
RADIATION DOSES
RADIATIONS
RADIOINDUCTION
RADIOSENSITIVITY EFFECTS
RODENTS
SURVIVAL CURVES
TEMPERATURE EFFECTS
TIME DEPENDENCE
VERTEBRATES
X RADIATION