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Issues in Risk Assessment (1993) / Chapter Skim
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3.2 Range of Possible TD50 Values
Pages 125-125

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From page 125...
... The absence of points in the upper left hand region is due to the lower limit on the number of tumors observed in the exposed groups in order to demonstrate a statistically significant increase in tumor occurrence. This implies that highly toxic chemicals of weak carcinogenic potency would likely go undetected in a standard bioassay, since such agents would not yield a measurable excess of tumors at the MTD.
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Key Terms

  • hand region
  • weibull model
  • correlation arises
  • toxic chemicals
  • design constraints

  • lower limit
  • tumors observed
  • scattergrams similar
  • print version
  • triangular regions

  • model allows
  • carcinogenic potency
  • highly toxic
  • constraints preclude
  • significant increase

  • left hand
  • weak carcinogenic
  • tumor occurrence
  • latter conclusion
  • experimental design

  • multistage models
  • observed tumor
  • background tumor
  • tumor rate
  • tumor occurring

  • tumor response
  • statistically significant
  • bioassay data
  • lowest correlation
  • standard bioassay


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