Triggering of DNA strand breaks by 45/sup 0/C hyperthermia and its influence on the repair of. gamma. -radiation damage in human white blood cells

Journal Article · Wed May 01 04:00:00 EDT 1985 · Cancer Res.; (United States)

OSTI ID:5964403

Mitchel, R E.J.; Birnboim, H C

Human peripheral white blood cells, freshly isolated from normal individual donors, were exposed to hyperthermia. Heat-generated DNA strand break damage and white blood cell capacity to repair radiation-induced breaks were determined by a fluorometric alkaline unwinding assay. Strand breaks could be readily detected when white blood cells were incubated in a physiological salt solution at temperatures between 41/sup 0/ and 46/sup 0/C, for times up to 90 min. The time course of strand break induction at 45/sup 0/C was characterized by a short initial lag, followed by a period of rapid break induction and subsequently a lower rate. Evidence is presented which suggests that the induction of DNA damage involved a triggering mechanism; a short treatment at 45/sup 0/C (10 to 20 min) initiated a cellular event which led to a rapid increase in the number of stand breaks during subsequent incubation of 37/sup 0/C. Continuous incubation at 45/sup 0/C produced less DNA damage than an initial period at 45/sup 0/C followed by incubation at 37/sup 0/C. This apparent triggering phenomenon was not due to a triggering of the respiratory burst in phagocytic cells, since no O/sub 2//sup -/ could be detected; in fact, a 30-min treatment at 45/sup 0/C largely blocked the capacity of the cells to respond normally to a soluble stimulator of the respiratory burst. Unlike ..gamma..-ray-induced breaks, 45/sup 0/C hyperthermia-induced breaks did not rejoin during subsequent incubation for up to 1 h at 37/sup 0/C. Additionally, 45/sup 0/C hyperthermia treatment progressively inhibited the ability of the cells to repair subsequent ..gamma..-ray-induced breaks (4 Gy). 17 references, 1 table.

• Research Organization: Atomic Energy of Canada Ltd., Chalk River, Ontario
• OSTI ID: 5964403
• Journal Information: Cancer Res.; (United States), Journal Name: Cancer Res.; (United States) Vol. 42; ISSN CNREA
• 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.
BIOLOGICAL EFFECTS
BIOLOGICAL MATERIALS
BIOLOGICAL RADIATION EFFECTS
BLOOD
BLOOD CELLS
BODY FLUIDS
BODY TEMPERATURE
DATA
DNA
ELECTROMAGNETIC RADIATION
EXPERIMENTAL DATA
GAMMA RADIATION
GENETIC EFFECTS
GENETIC RADIATION EFFECTS
HYPERTHERMIA
INFORMATION
IONIZING RADIATIONS
LEUKOCYTES
MATERIALS
NUCLEIC ACIDS
NUMERICAL DATA
ORGANIC COMPOUNDS
RADIATION EFFECTS
RADIATIONS
RADIOINDUCTION
STRAND BREAKS