title: Heritable non-lethal damage to cultured human cells irradiated with heavy ions.
abstract: During interplanetary flights the nuclei of all of a crew member's cells could be traversed by at least one high-LET (Linear Energy Transfer) cosmic-ray particle. In mammalian cells irradiated in vitro about 1 in 10,000 of the surviving cells traversed by heavy particles is transformed to malignancy or mutated. What, if anything, happens to the remaining >99% of surviving cells? A retrospective analysis of archived data and samples from heavy-ion irradiation experiments with cultured human cells in vitro indicated that heavy ions caused a dose- and LET-dependent reduction in growth rates of progeny of irradiated cells, based on colony-size distributions. The maximum action cross section for this effect is between 100 and 300 microm2, at least as large as the cell nuclear area and up to 3 times the cross section for cell killing. Thus, heritable slow growth is the most prevalent effect of high-LET radiations on cultured animal cells, which may have implications for crew health during deep space travel.
  
  
  CONCLUSIONS
  The views expressed in this article are those of the author(s) and do not necessarily reflect the views or policies of the USEPA.
authors.affiliation: U. S. Environmental Protection Agency, National Center for Environmental Assessment, Mail Code 8623-D, 1200 Pennsylvania Avenue, Washington, DC 20460, USA. Walker.James-Doctor@epa.gov
authors.forename: James T
authors.initials: JT
authors.lastname: Walker
authors.forename: Paul
authors.initials: P
authors.lastname: Todd
authors.forename: Olivia A
authors.initials: OA
authors.lastname: Walker
mesh_terms: D002477:Cells / Q000473:pathology* / Q000528:radiation effects*; D002478:Cells, Cultured; D004307:Dose-Response Relationship, Radiation; D020450:Heavy Ions; D006801:Humans; D018499:Linear Energy Transfer; D012189:Retrospective Studies