title: Estimation of distributions of time to appearance of tumor and time to death from tumor after appearance in mice fed 2-acetylaminofluorene.
abstract: A recently-developed statistical technique is employed to estimate parameters of the distributions of time to appearance of tumors and time to death from tumors after their appearance using both interval sacrifice and survival information. Estimates are obtained for three types of tumors at each of eight dose levels of 2-AAF, namely, 0, 30, 35, 60, 75, 100 and 150 ppm, which were administered to a total of 20880 female BALB/cStCrlfC3Hf/Nctr mice. For bladder neoplasms, the estimated median times to tumor ranged from 19.8 months at 150ppm to 1876.6 months at 0 ppm, while for liver neoplasms the extremes were 25.2 months at 150 ppm and 37.7 months at 0 ppm. Reticulum cell sarcomas occurred on the average at 24.7 months in all dose groups except 150 ppm, where the average time to appearance was 22.9 months. Although a pronounced dose-response for time-to-tumor was expressed for both bladder and liver neoplasms, the time required for death from either neoplasm following its appearance was not dose-related. The estimated median times to death after appearance of tumors were as follows: bladder neoplasm, 6.8 months; liver neoplasm, 5.7 months; reticulum cell sarcoma, 3.0 months.
mesh_terms: D015073:2-Acetylaminofluorene / Q000633:toxicity*; D000818:Animals; D005260:Female; D008113:Liver Neoplasms / Q000139:chemically induced / Q000401:mortality; D051379:Mice; D008807:Mice, Inbred BALB C; D009374:Neoplasms, Experimental / Q000139:chemically induced* / Q000401:mortality; D013223:Statistics as Topic; D013997:Time Factors; D001749:Urinary Bladder Neoplasms / Q000139:chemically induced / Q000401:mortality
chemical_list: D015073:2-Acetylaminofluorene