title: A semi-automated micronucleus-centromere assay to assess low-dose radiation exposure in human lymphocytes.
abstract: OBJECTIVE
  The in vitro micronucleus (MN) assay is a reliable method to assess radiation-induced chromosomal damage in human peripheral blood lymphocytes. It is used to evaluate in vivo radiation over-exposure and to assess in vitro chromosomal radiosensitivity. A limitation of the MN assay is the relatively high and variable spontaneous MN frequency that restricts low-dose estimation to doses of about 0.3 gray (Gy). As radiation-induced MN mainly contain acentric fragments and spontaneous MN originate from lagging chromosomes, both MN types can be distinguished from each other by using fluorescence in situ hybridisation (FISH) with a pan-centromeric probe. The aim of this study was to investigate if the sensitivity, reliability and processing time of the MN assay can be enhanced by combining the automated MN assay with pan-centromere scoring.
  
  
  METHODS
  Blood samples from 10 healthy donors were irradiated in vitro with low doses of gamma-rays. Dose response curves were determined for fully-automated and semi-automated MN scoring and semi-automated scoring of centromere negative MN (MNCM-).
  
  
  RESULTS
  A good correlation was obtained between fully-automated and semi-automated MN scoring (r(2) = 0.9973) and between fully automated MN scoring and semi-automated scoring of MNCM- (r(2) = 0.998). With the Wilcoxon test, a significant p value was obtained between 0 and 0.2 Gy for the fully-automated MN analysis, between 0 and 0.1 Gy for semi-automated MN analysis and between 0 and 0.05 Gy for semi-automated scoring of MNCM-.
  
  
  CONCLUSIONS
  The semi-automated micronucleus-centromere assay combines high-speed MN analysis with a more accurate assessment in the low-dose range which makes it of special interest for large-scale radiation applications.
authors.affiliation: National Research Foundation - iThemba LABS, Somerset West, South Africa. ansbaeyens@hotmail.com
authors.forename: Ans
authors.initials: A
authors.lastname: Baeyens
authors.forename: Rosemary
authors.initials: R
authors.lastname: Swanson
authors.forename: Olivia
authors.initials: O
authors.lastname: Herd
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Ainsbury
authors.forename: Thulani
authors.initials: T
authors.lastname: Mabhengu
authors.forename: Pascale
authors.initials: P
authors.lastname: Willem
authors.forename: Hubert
authors.initials: H
authors.lastname: Thierens
authors.forename: Jacobus P
authors.initials: JP
authors.lastname: Slabbert
authors.forename: Anne
authors.initials: A
authors.lastname: Vral
mesh_terms: D000328:Adult; D001331:Automation; D002503:Centromere / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007211:Indoles / Q000378:metabolism; D008214:Lymphocytes / Q000166:cytology* / Q000378:metabolism / Q000528:radiation effects*; D015162:Micronucleus Tests / Q000379:methods*; D008875:Middle Aged; D015203:Reproducibility of Results; D013997:Time Factors; D055815:Young Adult
chemical_list: D007211:Indoles; C007293:DAPI