Induction and repair of DNA breaks in rat epidermis irradiated with electrons

Journal Article · Thu Jan 01 04:00:00 EST 1981 · Radiat. Res.; (United States)

DOI:https://doi.org/10.2307/3575547· OSTI ID:5238138

Burns, F J; Sargent, E V

The dependence of DNA strand breaks (alkali-labile sites) on radiation dose and the rate of repair of such breaks were determined by means of an alkaline unwinding technique. The epidermal DNA was labeled with /sup 3/H prior to irradiation by giving intraperitoneal injections of (/sup 3/H)thymidine. After irradiation the epidermal cells were removed and incubated in an alkaline solution. After the incubation in alkali, S/sub 1/ nuclease was added to digest the single-stranded portion of the DNA. The amount of undigested double-stranded DNA was determined by using a liquid scintillation counter to count the /sup 3/H in the precipitated DNA. Plots of percentage double-stranded DNA versus time in alkali, referred to as unwinding curves, were utilized to estimate the number of strand breaks (alkali-labile sites) per unit DNA. The strand breaks were found to increase in proportion to radiation dose within the 300- to 2400-rad dose range employed in the experiment. When the skin was given 1200 rad, the strand breaks were found to be removed with a halftime of about 21 min. This halftime implies a rate of removal much too rapid for single-strand breaks to be the major repairable component of carcinogenic injury, since the latter was found in separate experiments to be removed with a halftime between 110 and 240 min.

• Research Organization: New York Univ. Medical Center, New York
• DOE Contract Number: AC02-76EV03380
• OSTI ID: 5238138
• Journal Information: Radiat. Res.; (United States), Journal Name: Radiat. Res.; (United States) Vol. 87; ISSN RAREA
• Country of Publication: United States
• Language: English

Related Subjects

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560114 -- Radiation Effects on Biochemicals-- In Animals-- (-1987)
560152* -- Radiation Effects on Animals-- Animals
59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMAL TISSUES
ANIMALS
AZINES
BIOLOGICAL EFFECTS
BIOLOGICAL PATHWAYS
BIOLOGICAL RADIATION EFFECTS
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
BODY
DNA
DOSE-RESPONSE RELATIONSHIPS
DOSES
EPIDERMIS
EPITHELIUM
EXTERNAL IRRADIATION
HETEROCYCLIC COMPOUNDS
IRRADIATION
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MAMMALS
NUCLEIC ACIDS
NUCLEOSIDES
NUCLEOTIDES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
PYRIMIDINES
RADIATION DOSES
RADIATION EFFECTS
RADIOINDUCTION
RATS
RECOVERY
REPAIR
RIBOSIDES
RODENTS
SKIN
STRAND BREAKS
THYMIDINE
TISSUES
TRACER TECHNIQUES
TRITIUM COMPOUNDS
VERTEBRATES