Document Detail


Bayesian estimation of pharmacokinetic and pharmacodynamic parameters in a mode-of-action-based cancer risk assessment for chloroform.
MedLine Citation:
PMID:  18093051     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Chloroform is a carcinogen in rodents and its carcinogenicity is secondary to events associated with cytotoxicity and regenerative cell proliferation. In this study, a physiologically based pharmacokinetic/pharmacodynamic (PBPK/PD) model that links the processes of chloroform metabolism, reparable cell damage, cell death, and regenerative cellular proliferation was developed to support a new cancer dose-response assessment for chloroform. Model parameters were estimated using Markov Chain Monte Carlo (MCMC) analysis in a two-step approach: (1) metabolism parameters for male and female mice and rats were estimated against available closed chamber gas uptake data; and (2) PD parameters for each of the four rodent groups were estimated from hepatic and renal labeling index data following inhalation exposures. Subsequently, the resulting rodent PD parameters together with literature values for human age-dependent physiological and metabolism parameters were used to scale up the rodent model to a human model. The human model was used to predict exposure conditions under which chloroform-mediated cytolethality is expected to occur in liver and kidney of adults and children. Using the human model, inhalation Reference Concentrations (RfCs) and oral Reference Doses (RfDs) were derived using an uncertainty factor of 10. Based on liver and kidney dose metrics, the respective RfCs were 0.9 and 0.09 ppm; and the respective RfDs were 0.4 and 3 mg/kg/day.
Authors:
Kai H Liao; Yu-Mei Tan; Rory B Conolly; Susan J Borghoff; Michael L Gargas; Melvin E Andersen; Harvey J Clewell
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Risk analysis : an official publication of the Society for Risk Analysis     Volume:  27     ISSN:  0272-4332     ISO Abbreviation:  Risk Anal.     Publication Date:  2007 Dec 
Date Detail:
Created Date:  2007-12-20     Completed Date:  2008-02-27     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8109978     Medline TA:  Risk Anal     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1535-51     Citation Subset:  IM    
Affiliation:
Center for Human Health Assessment, The Hamner Institutes for Health Sciences, Research Triangle Park, NC 27709, USA.
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MeSH Terms
Descriptor/Qualifier:
Animals
Bayes Theorem
Biological Transport, Active
Carcinogens / pharmacokinetics,  pharmacology,  toxicity*
Chloroform / pharmacokinetics*,  pharmacology,  toxicity*
Environmental Exposure
Female
Humans
Kidney / metabolism
Liver / metabolism
Male
Markov Chains
Mice
Models, Biological
Monte Carlo Method
Neoplasms / chemically induced
Neoplasms, Experimental / chemically induced*,  metabolism
Rats
Rats, Inbred F344
Risk Assessment
Chemical
Reg. No./Substance:
0/Carcinogens; 67-66-3/Chloroform

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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