Radiation and hypothermia: changes in DNA supercoiling in human diploid fibroblasts

• The influence of hypothermia (2 degrees, 15 degrees and 28 degrees C) upon the effect of X-irradiation on chromatin from human diploid fibroblast cells (AG1518) was studied using the fluorescent halo assay. Rewinding of supercoils was inhibited in a dose-dependent manner when cells were irradiated with 4, 8 or 16 Gy. This inhibition of rewinding was reduced when cells were irradiated at subnormal temperatures compared with cells irradiated at 37 degrees C. One hour's preincubation at low temperature did not influence rewinding. When AG1518 cells were irradiated at 37 degrees C in the presence of the radical scavenger DMSO (0.5 M), the radiation-induced damage was reduced. No additional protection of DMSO in hypothermic cells (2 degrees C) was found, possibly indicating that OH-radical-mediated effects are more temperature dependent. These results are similar to those recently found for the malignant MCF-7 cell line.

Subject headings

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Cancer och onkologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Cancer and Oncology (hsv//eng)

NATURVETENSKAP  -- Biologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences (hsv//eng)

Keyword

*Cold

DNA

Superhelical/chemistry/*radiation effects

Dimethyl Sulfoxide/chemistry

*Diploidy

Fibroblasts/metabolism

Free Radical Scavengers/chemistry

Humans

Nucleic Acid Conformation/*radiation effects

radiation

Publication and Content Type

ref (subject category)

art (subject category)