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Influence of Helicobacter hepaticus Infection on the Chronic Toxicity and Carcinogenicity of Triethanolamine in B6C3F1 MiceNational Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA Correspondence: Dr. John R. Bucher, NIEHS, PO Box 12233, MD EC-34, Research Triangle Park, NC 27709, USA; e-mail:bucher{at}niehs.nih.gov. Helicobacter hepaticus (H. hepaticus) infection causes hepatitis and increased hepatocellular neoplasms in male mice; although females are also infected, liver lesions are not typically expressed. In the 1990s, B6C3F1 mice from some chronic National Toxicology Program (NTP) studies were found to be infected with H. hepaticus. In these studies, there was hepatitis in many of the males, and there were more hepatocellular neoplasms in control males compared to studies with uninfected mice. In one of these studies, increased hepatocellular neoplasms at the high doses in male and female mice exposed topically to triethanolamine (TEA) provided the only evidence of carcinogenic activity. This study was repeated in mice free of H. hepaticus.However, the NTP mouse production colony and the diet differed between studies; these differences were the result of NTP programmatic decisions. In repeat study males, although control incidences were similar between studies, exposure did not result in increased hepatocellular neoplasms. In repeat study females, the control incidence of hepatocellular neoplasms was half that observed in the initial study, and these neoplasms were increased over controls at all doses. These data suggest that in the initial study, H. hepaticusinfluenced the induction of hepatocellular neoplasms in males, but not in females.
Key Words: National Toxicology Program triethanolamine Helicobacter hepaticus mice hepatocellular neoplasms Abbreviations: H. hepaticus, Helicobacter hepaticus NTP, National Toxicology Program TEA, triethanolamine eosinophilic foci, eosinophilic foci of altered hepatocytes
This version was published on October
1, 2008 Toxicologic Pathology, Vol. 36, No. 6,
783-794 (2008) |
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