Oncogenic potential of inhaled XXXX in the nose of @entity35 and hamsters after 1 or 10 1-hr exposures.

@entity1 @entity39 @entity5 @entity75 @entity1373 @entity2490 @entity7228 @entity7783 @entity329 @entity35 @entity652
@entity7783 ( @entity7228 ) is used as a fuel for missiles and standby power systems of operational military aircraft. Maintenance of missiles and aircraft may result in accidental @entity1 exposure to high concentrations for brief periods of time. The purposes of this study were to assess the oncogenic potential of @entity7228 in @entity35 and male hamsters exposed to a high concentration of @entity7228 for repeated short exposures and to investigate the relationships of acute and subchronic effects of @entity7228 to nasal tumorigenesis. In phase 1 (acute and subchronic) and Phase 2 (lifetime experiments, groups of male and female Fischer 344 @entity35 and male @entity329 were exposed by inhalation to 0, 75 (Phase 2 only), or 750 ppm @entity7228 for 1 (acute) or 10 (subchronic) 1-hr weekly exposures. Rodents were euthanized 24 hr after exposures 1 and 10 and 24 to 30 months poststudy initiation. Significant reductions in body weight were observed in @entity7228 -treated rodents compared to controls during the exposure interval. No @entity7783 -induced mortality was detected. Histopathologic examination after the acute and subchronic exposures revealed @entity39 of transitional, respiratory, and olfactory epithelia in the anterior nose and, in @entity35 exposed subchronically, squamous metaplasia of the transitional epithelium. Minimal to mild @entity2490 resulted from @entity7228 exposures. Apoptosis was observed in olfactory and squamous metaplastic transitional epithelium. Lesions occurred at sites reportedly having high air-flow and generally appeared to be more severe in the anterior portion of the nose. By 24 months, the squamous metaplastic transitional epithelium reverted back to normal-appearing transitional epithelium. By 24+ months, low incidences (sexes combined) of @entity1373 (5/194, 2.6%) and @entity5 (11/194, 5.7%) were detected, principally in the transitional epithelium of the 750 ppm @entity7228 -treated @entity35 . A similar incidence of @entity1373 (2/94, 2%) and @entity5 (5/94, 5.3%) was detected in the high-exposure group of hamsters. The location and type of @entity7228 -induced @entity75 were similar to those reported in a chronic @entity7228 -exposure study (5.0 ppm x 6 hr/day x 5 days/week for 1 year) conducted in our laboratory, but the chronic study had much higher incidences ( @entity35 , sexes combined: @entity1373 15.5% vs 2.6% and polypoid @entity652 44.6% vs 5.2%). The product (CD) of concentration + time was the same (750 ppm hours) for the high-dose groups for both studies, but the duration of exposure was 150 x longer and the concentration was 150 x lower in the chronic study.(ABSTRACT TRUNCATED AT 400 WORDS)
