title: Adaptive response and dose-response plateaus for initiation in a state-vector model of carcinogenesis.
abstract: OBJECTIVE
  To investigate whether it is possible to explain dose-response plateaus for in-vitro X-ray irradiation of different cell lines with radioprotective mechanisms such as radiologically induced expression of scavengers and repair enzymes.
  
  
  METHODS
  A biomathematical model was developed based on a previous state-vector model. New features of the model are a mathematical description of enhanced repair and radical scavenging as a result of irradiation.
  
  
  RESULTS
  The model produces a plateau in the dose-response for in-vitro tranformations between 0.5 and 1 Gy and for chromosome aberrations and it predicts an inverse-fractionation effect within a selected range of doses.
  
  
  CONCLUSIONS
  Adaptive response mechanisms within a state-vector model provide a coherent explanation of the dose-response characteristics for in-vitro transformations and chromosomal aberrations. These results suggest the need for new experimental studies described in the paper.
authors: Institute for Environmental Studies, University of North Carolina at Chapel Hill, 27599-1105, USA.
authors: H
authors: H
authors: Schöllnberger
authors: M
authors: M
authors: Kotecki
authors: D
authors: D
authors: Crawford-Brown
authors: W
authors: W
authors: Hofmann
authors: P
authors: P
authors: Eckl
mesh_terms: D000220:Adaptation, Biological / Q000502:physiology*; D000818:Animals; D002471:Cell Transformation, Neoplastic / Q000528:radiation effects; D004247:DNA / Q000528:radiation effects; D004249:DNA Damage; D004307:Dose-Response Relationship, Radiation; D008432:Mathematical Computing; D051379:Mice; D008954:Models, Biological; D015233:Models, Statistical; D009381:Neoplasms, Radiation-Induced / Q000209:etiology* / Q000235:genetics; D011836:Radiation Tolerance / Q000502:physiology*; D014965:X-Rays
chemical_list: D004247:DNA