title: Chromosomal radiosensitivity study of temporary nuclear workers and the support of the adaptive response induced by occupational exposure.
abstract: OBJECTIVE
  To study chromosomal radiosensitivity in a population of radiation workers and investigate the possibility of an adaptive response in lymphocytes of workers after short-term occupational exposure to ionizing radiation.
  
  
  METHODS
  The studied group comprised 41 workers temporarily employed at the Nuclear Power Plant Doel (Belgium) for reactor maintenance. A blood sample was taken before and directly after the exposure period of about 1 month. Chromosomal radiosensitivity was assessed in vitro by the G2 assay and the G0 micronucleus (MN) assay. For the MN assay, a low dose-rate (LDR) in vitro irradiation protocol was applied in addition to high dose-rate (HDR) irradiation of the blood samples in order to determine the dose-rate sparing (DRS) effect.
  
  
  RESULTS
  No statistically significant effect of the occupational exposures (up to 10 mSv) on the baseline MN frequencies without in vitro irradiation was observed. A comparison of the number of chromatid aberrations pre- and post-exposure shows no effect of the occupational exposure. On the other hand, the G0-MN assay with the LDR irradiation protocol reveals a systematic reduction in chromosomal radiosensitivity by the exposure, increasing with dose. For workers who received the highest dose (4-10 mSv) a statistically significant (p <0.05) decrease of the in vitro induced MN yields and increase of the dose-rate sparing was observed.
  
  
  CONCLUSIONS
  Short-term low-dose occupational exposure may act as an in vivo adaptive dose and stimulate repair in G0 lymphocytes.
authors.affiliation: Department of Anatomy, Embryology, Histology and Medical Physics, Ghent University, Proeftuinstraat 86, Belgium. hubert.thierens@rug.ac.be
authors.forename: H
authors.initials: H
authors.lastname: Thierens
authors.forename: A
authors.initials: A
authors.lastname: Vral
authors.forename: M
authors.initials: M
authors.lastname: Barbé
authors.forename: M
authors.initials: M
authors.lastname: Meijlaers
authors.forename: A
authors.initials: A
authors.lastname: Baeyens
authors.forename: L De
authors.initials: LD
authors.lastname: Ridder
mesh_terms: D000293:Adolescent; D000328:Adult; D002875:Chromosomes / Q000528:radiation effects* / Q000648:ultrastructure*; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D015162:Micronucleus Tests; D008875:Middle Aged; D009152:Mutagenicity Tests; D016273:Occupational Exposure / Q000009:adverse effects*; D011210:Power Plants; D011829:Radiation Dosage; D013997:Time Factors