Triggering of DNA strand breaks by 45 degrees 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:5227998

Mitchel, R E; 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 degrees and 46 degrees C, for times up to 90 min. The time course of strand break induction at 45 degrees 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 degrees C (10 to 20 min) initiated a cellular event which led to a rapid increase in the number of strand breaks during subsequent incubation of 37 degrees C. Continuous incubation at 45 degrees C produced less DNA damage than an initial period at 45 degrees C followed by incubation at 37 degrees C. This apparent triggering phenomenon was not due to a triggering of the respiratory burst in phagocytic cells, since no O/sub 2/- could be detected; in fact, a 30-min treatment at 45 degrees 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 degrees C hyperthermia-induced breaks did not rejoin during subsequent incubation for up to 1 h at 37 degrees C.

• Research Organization: Chalk River Nuclear Labs., Ontario
• OSTI ID: 5227998
• Journal Information: Cancer Res.; (United States), Journal Name: Cancer Res.; (United States) Vol. 5; 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
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
BLOOD
BLOOD CELLS
BODY FLUIDS
BODY TEMPERATURE
DNA
DNA REPAIR
ELECTROMAGNETIC RADIATION
GAMMA RADIATION
GENETIC EFFECTS
GENETIC RADIATION EFFECTS
HYPERTHERMIA
IN VITRO
IONIZING RADIATIONS
LEUKOCYTES
MATERIALS
NUCLEIC ACIDS
ORGANIC COMPOUNDS
RADIATION EFFECTS
RADIATIONS
RECOVERY
REPAIR
STRAND BREAKS
TEMPERATURE EFFECTS