title: A simple method for simultaneous interphase-metaphase chromosome analysis in biodosimetry.
abstract: OBJECTIVE
  To find a simple protocol for measuring chromosome damage both in G1 and in G2/M chromosomes, to overcome problems related to low mitotic index and cell-cycle alterations in biodosimetric tests.
  
  
  METHODS
  The protocol is based on the use of calyculin A to induce premature chromosome condensation in human peripheral blood lymphocytes in different phases of the cell cycle. Chromosome exchanges were measured by fluorescence in situ hybridization (chromosomes 2 and 4) in lymphocytes from four different donors. Cells were exposed to 4Gy X-rays and the results were compared to aberrations in M phase (colcemid block) and G0 (premature chromosome condensation induced by fusion to mitotic hamster cells).
  
  
  RESULTS
  Treatment with calyculin A produced a high fraction of chromosome condensation in different phases of the cell cycle. Cells in G1 and G2/M could be scored simultaneously for biodosimetry by chromosome painting. The condensation index was 5-20 times higher than the mitotic index (colcemid alone). The calyculin A treatment did not produce a significant increase in the background of chromosomal aberrations or modify the yield of chromosomal aberrations scored after exposure to X-rays.
  
  
  CONCLUSIONS
  Induction of chromosome condensation by calyculin A is a powerful biodosimetric tool, which provides a high number of spreads for analysis and overcomes problems related to poor in vitro growth or cell-cycle alterations.
authors.affiliation: Space and Particle Radiation Group, National Institute of Radiological Sciences, Chiba, Japan. durante@nirs.go.jp
authors.forename: M
authors.initials: M
authors.lastname: Durante
authors.forename: Y
authors.initials: Y
authors.lastname: Furusawa
authors.forename: E
authors.initials: E
authors.lastname: Gotoh
mesh_terms: D002453:Cell Cycle / Q000528:radiation effects; D002869:Chromosome Aberrations / Q000235:genetics; D002875:Chromosomes / Q000528:radiation effects*; D006801:Humans; D007399:Interphase / Q000235:genetics* / Q000528:radiation effects; D008214:Lymphocytes / Q000473:pathology; D008387:Marine Toxins; D008677:Metaphase / Q000235:genetics*; D008856:Microscopy, Fluorescence; D008938:Mitosis / Q000528:radiation effects; D010080:Oxazoles / Q000494:pharmacology; D011874:Radiometry / Q000379:methods*; D014965:X-Rays / Q000009:adverse effects
chemical_list: D008387:Marine Toxins; D010080:Oxazoles; C059041:calyculin A