Exposure temperature, but not donor age, is a confounding factor for in vitro translocation production by chronic irradiation

Int J Radiat Biol. 1999 Jun;75(6):673-80. doi: 10.1080/095530099140005.

Abstract

Purpose: To assess the effects of incubation temperature during irradiation, and of donor age, on the in vitro induction of chromosomal translocations in human lymphocytes.

Material and methods: Lymphocytes from six human male donors were scored, using fluorescence in situ hybridization, for the presence of chromosomal translocations involving chromosomes 1 to 6 after in vitro, chronic exposure (delivered continuously over 48 h at 37 degrees C or at 20 degrees C) to tritium beta-rays or 60Co gamma-rays.

Results: No age-related difference in the alpha coefficients of the fitted induction curves was observed for gamma-ray-exposed lymphocytes obtained from four donors whose ages ranged from 24 to 79 years, or for tritium beta-ray-exposed lymphocytes from two donors aged 36 and 62 years. Duplicate samples from one donor, irradiated concurrently at 20 degrees C or 37 degrees C, gave significantly different alpha coefficients: 0.128+/-0.008 and 0.053+/-0.004, respectively (p<0.0001). The S-ratio (the ratio of induced complete to incomplete translocations) was found to be independent of radiation dose, donor age and exposure temperature.

Conclusions: For biodosimetry in chronic irradiation situations, the use of alpha coefficients derived from the dose-response curves of cells chronically irradiated in vitro at body temperature is recommended. With respect to induction rates, donor age does not appear to be a confounding factor. The S-ratio is independent of radiation doses, exposure temperatures, or donor ages.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adult
  • Age Factors
  • Aged
  • DNA Damage
  • DNA Repair
  • Dose-Response Relationship, Radiation
  • Humans
  • Lymphocytes / radiation effects*
  • Lymphocytes / ultrastructure
  • Male
  • Middle Aged
  • Relative Biological Effectiveness
  • Temperature
  • Translocation, Genetic / radiation effects*