Bioassay of XXXX for possible carcinogenicity.

@entity5585 @entity706 @entity19 @entity5 @entity35 @entity3127 @entity2401
A bioassay of the tuberculostatic drug @entity5585 for possible carcinogenicity was conducted by administering the test chemical in feed to Fischer 344 @entity35 and B6C3F1 @entity19 . Groups of 35 @entity35 and 35 @entity19 of each sex were administered @entity5585 at one of two doses, either 5,000 or 10,000 ppm, for 78 weeks, and then observed for an additional 26 or 27 weeks. Matched controls consisted of groups of 15 untreated @entity35 and 15 untreated @entity19 of each sex. High-dose male @entity19 died or were killed by week 92; all other surviving animals were killed at weeks 104 or 105. Mean body weights of the dosed male @entity35 were slightly lower than those of the matched controls, while mean body weights of the dosed females were more nearly comparable to those of the controls. A sufficient number of @entity35 in each group was at risk to termination of the study at weeks 104-105 for the development of late-appearing @entity5 . In @entity19 , administration of @entity5585 had no consistent effect on mean body weights. Survival to termination of the study was low, particularly among the control groups. In @entity35 , no lesions could clearly be related to administration of the chemical. In @entity19 , interstitial and suppurative @entity2401 in the dosed animals and @entity3127 in both dosed and matched control @entity19 of each sex were associated with increased deaths. In the females, there was a significant positive dose-related trend (P=0.037) in the incidence of @entity706 (matched controls 0/13, low-dose 2/25, high-dose 6/29); however, the incidences in each of the dosed groups were not significant when compared with that in the matched controls. In addition, the poor survival and the small size of the control group precluded making a clear association of the incidence of these @entity5 with administration of the chemical. It is concluded that under the conditions of this bioassay, the early deaths and small size of the control group precluded a conclusion regarding the carcinogenicity of @entity5585 in female B6C3F1 @entity19 . @entity5585 was not carcinogenic for Fischer 344 @entity35 or for male @entity19 .
