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National Cancer Institute... 1978A bioassay of technical-grade mexacarbate for possible carcinogenicity was conducted using Osborne-Mendel rats and B6C3F1 mice. Mexacarbate was administered in the feed,...
A bioassay of technical-grade mexacarbate for possible carcinogenicity was conducted using Osborne-Mendel rats and B6C3F1 mice. Mexacarbate was administered in the feed, at either of two concentrations, to groups of 50 male and 50 female animals of each species. The time-weighted average high and low dietary concentrations of mexacarbate were 418 and 209 ppm for male rats, 678 and 339 ppm for female rats, 654 and 327 ppm for male mice and 135 and 68 ppm for female mice. After a 78-week period of chemical administration, observation of rats continued for an additional 33 to 34 weeks and observation of mice continued for 14 to 15 additional weeks. For each species, 20 animals of each sex were placed on test as controls. All groups except the male control mice survived sufficiently long to be at risk from late-appearing tumors. Because of poor survival of the male control mice, a pooled control group was used for statistical analysis of tumor incidence in male mice. The possibility that female mice in this study did not receive maximum tolerated dosages of mexacarbate should be considered. Administration of mexacarbate had no significant effect on survival or body weights of female mice. No neoplasms occurred in statistically significant increased incidences when dosed rats were compared to controls. Among male mice surviving at least 56 weeks, significant associations with dietary concentrations were indicated by the Cochran-Armitage test for hepatocellular carcinomas, for subcutaneous fibrosarcomas and for fibromas of the skin. In none of these cases, however, were these results supported by significant Fisher exact tests. Under the conditions of this bioassay, sufficient evidence was not obtained for the carcinogenicity of mexacarbate for Osborne-Mendel rats or B6C3F1 mice.
PubMed: 12799715
DOI: No ID Found -
Bulletin of the World Health... 1965In view of the increasing importance of carbamic acid esters in insect control, the authors have conducted studies on the inheritance of carbamate-resistance in the...
In view of the increasing importance of carbamic acid esters in insect control, the authors have conducted studies on the inheritance of carbamate-resistance in the housefly Resistance to Isolan (1-isopropyl-3-methyl-5-pyrazolyl dimethylcarbamate) in carbamate-selected strains is inherited as a partially dominant major single factor, without sex linkage or appreciable cytoplasmic influence. Inclusion of piperonyl butoxide as a synergist with Sevin (1-naphthyl methylcarbamate), Zectran (4-dimethylamino-3,5-xylyl methylcarbamate), or m-isopropylphenyl methylcarbamate also produced evidence of monofactorial inheritance.In contrast, resistance to Isolan and to a combination of Sevin and piperonyl butoxide in a ronnel-selected strain is inherited in a pattern suggestive of a polygenic system.The results obtained are discussed in the light of previously established data on the rate of development, stability and regression of carbamate-resistance.
Topics: Animals; Carbamates; Genetics; Houseflies; Insect Control; Insecticide Resistance; Insecticides; Organothiophosphorus Compounds; Research
PubMed: 14310905
DOI: No ID Found