title: A cytogenetic approach to the effects of low levels of ionizing radiation (IR) on the exposed Tunisian hospital workers.
abstract: OBJECTIVE
  The aim of this study is to assess chromosomal damage in Tunisian hospital workers occupationally exposed to low levels of ionizing radiation (IR).
  
  
  METHODS
  The cytokinesis-block micronucleus (CBMN) assay in the peripheral lymphocytes of 67 exposed workers compared to 43 controls matched for gender, age and smoking habits was used. The clastogenic/aneugenic effect of IR was evaluated using the CBMN assay in combination with fluorescence in situ hybridization with human pan-centromeric DNA in all the exposed subjects and controls.
  
  
  RESULTS
  The study showed a significant increase of the micronucleus (MN) frequency in the lymphocytes of the exposed workers compared to the control group (13.63 ± 4.9‰ vs. 6.52 ± 4.21‰, p < 0.05). The centromere analysis performed in our study showed that MNs in hospital staff were predominantly centromere negative (72%) and the mean negative labeled micronucleus (C-MN) frequency was significantly higher in the exposed subjects than in the controls (9.04 ± 4.57‰ vs. 1.17 ± 0.77‰). The multivariate regression analysis, taking into account all confounding factors, showed that only the time of exposure to IR had a significant effect on the level of MNs and C-MN.
  
  
  CONCLUSIONS
  The present study shows that chromosomal damage leading to the formation of micronucleated lymphocytes is more frequent in the hospital workers exposed to IR than in the controls, despite the low levels of exposure. The results of the study confirm the well-known clastogenic properties of ionizing radiation. In regards to health monitoring, detection of early genotoxic effects may allow for the adoption of preventive biological control measures, such as hygienic improvements in the workplace or reduction of hours of occupational exposure.
authors.affiliation: Department of Cytogenetic and Reproductive Biology, Farhat Hached University Teaching Hospital, Sousse, Tunisia. sana_bouraoui@yahoo.fr
authors.forename: Sana
authors.initials: S
authors.lastname: Bouraoui
authors.forename: Soumaya
authors.initials: S
authors.lastname: Mougou
authors.forename: Afef
authors.initials: A
authors.lastname: Drira
authors.forename: Faten
authors.initials: F
authors.lastname: Tabka
authors.forename: Nouha
authors.initials: N
authors.lastname: Bouali
authors.forename: Najib
authors.initials: N
authors.lastname: Mrizek
authors.forename: Hatem
authors.initials: H
authors.lastname: Elghezal
authors.forename: Ali
authors.initials: A
authors.lastname: Saad
mesh_terms: D000328:Adult; D003582:Cytogenetics / Q000379:methods*; D004249:DNA Damage; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009784:Occupational Diseases / Q000453:epidemiology / Q000235:genetics*; D016273:Occupational Exposure / Q000009:adverse effects*; D010564:Personnel, Hospital; D011829:Radiation Dosage; D011832:Radiation Injuries / Q000453:epidemiology / Q000235:genetics*; D011839:Radiation, Ionizing; D014416:Tunisia / Q000453:epidemiology