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Biomedical subjects

M Hite

Publications and source records attributed to M Hite.

6 recordsLinked to original sources
PubMed1979

Mutagenic evaluation of nitroparaffins in the Salmonella typhimurium/mammalian-microsome test and the micronucleus test.

Three nitroparaffins (nitroethane, 1-nitropropane, and 2-nitropropane) were studied in the Salmonella typhimurium/mammalian microsome (Ames) test, with and without microsomal activation systems. Nitroethane and 2-nitropropane also were studied in an in vivo mutagenic (micronucleus) test. These studies were undertaken because these solvents are widely used in the chemical and pharmaceutical industries and 2-nitropropane was reported to cause liver cancer in rats exposed by the inhalation route. Neither nitroethane nor 1-nitropropane was active in the Ames test with Salmonella tester-strains TA1537, TA92, TA98, or TA100. However, 2-nitropropane produced a significant increase in revertants in all of these tester strains, particularly strain TA100, where 3 microliter/plate doubled the number of revertants in the presence of microsomal enzymes. Negative results were obtained with both nitroethane and 2-nitropropane in micronucleus tests. These studies have shown that 2-nitropropane has the potential for causing point mutations in a microbial test system. However, this compound probably will not cause a chromosome mutation of the clastogenic type.

Alkanes↗
PubMed1979

Acute toxicity of methyl fluorosulfonate (Magic Methyl).

Methyl fluorosulfonate (Magic Methyl), an active methylating agent used by research chemists, was studied for acute oral toxicity, acute inhalation toxicity, ocular irritation, and dermal irritation. This compound is very hazardous and may have been responsible for at least one human death. The results of these studies confirmed that Magic Methyl is markedly toxic by all routes studied and particularly by the inhalation route since the LC50 value for rats was found to be between 5 and 6 ppm.

Administration, Oral↗
PubMed1977

The effect of cyproheptadine on the chromosomes of human lymphocytes in vitro.

The effect of 4-[5-dibenzo(alpha,alpha)-cyclohepten-5-ylidene]-1-methylpiperidine (cyproheptadine, Periactinol) on the chromosomes of human lymphocytes in vitro was investigated. Cell cultures that had been established for 48 h from lymphocytes obtained from the peripheral blood of four volunteers were exposed for an additional 24 h to drug concentrations of 2.54 X 10(-5), 5.09 X 10(-5), 1.02 X 10(-4), or 2.03 X 10(-4) Mol/l. No variations or aberrations were seen in the chromosomes of human lymphocytes that could be definitely related to treatment with cyproheptadine.

Age Factors↗
PubMed1977

Effect of cage size on patterns of activity and health of beagle dogs.

Thirty-two male beagle dogs were assigned at random, 16 to standard size cages (30 X 30 X 30 inches) and 16 to large cages (90 X 30 X 30 inches) for a period of 13 weeks, and then were "crossed-over" for an additional period of 13 weeks. The dogs were observed daily and weighed weekly. Electrocardiographic and ophthalmologic examinations were made once and hematologic and biochemical measurements were made twice during the control period and at monthly intervals during the study. Photographs were taken of each dog every 60 seconds, 7 days a week, for about 8.5 hours each day. The film was processed and analyzed for the acf standing sitting, lying, or sleeping. In addition, dogs in the large cages were scored for the region (front, middle, or back) occupied. No statistically significant differences were found between dogs in the standard or large cages with respect to weight gain, percent of time standing, and percent of time sleeping. Statistically significant (p less than 0.05) differences were found for percent of time sitting (standard cages 12.7%; large cages 9.4%) and percent of time lying (standard cages 6.6%; large cages 8.3%); however, the differences were not large enough to be of any practical concern. Transient patterns of response over 13-week periods of the study were essentially the same (statistically verified) for dogs in either size cage. Also statistical results showed that there was no significant carryover (residual) effect associated with any of the parameters measured. No beneficial or adverse effects were noted that could be related to the size of the two cages. The size of the standard cage appeared adequate for laboratory beagle dogs and no advantage was found when the dogs were in larger cages with respect to behavior, patterns of activity, or health.

Animals↗
PubMed1976

Mutagenic evaluation of ronidazole.

Ronidazole was evaluated for mutagenic potential using in vitro microbial tests and in vivo studies in mice. The microbial test used the histidine requiring mutants of Salmonella typhimurium with and without a rat liver microsomal activation system (Ames test). The studies in mice included the dominant lethal test, micronucleus test and cytogenetic assays. Ronidazole was given orally in doses of 50, 100 and 200 mg/kg/day in the in vivo studies. In the dominant lethal test, groups of male mice were treated for five consecutive days before being mated with untreated females. In the micronucleus test, the mice were administered the compound for 2 or 5 consecutive days; they were killed 6 h after the last dose and bone marrow was examined for the presence of micronuclei in developing erythrocytes. In the cytogenetic assays, bone marrow cells in metaphase were examined for chromosome aberrations, 6, 24 and 48 h after mice were treated acutely with the test compound. In addition, similar examinations of chromosomes were made on mice given five consecutive dosages of ronidazole and killed 6 h after the last dose. The results of the various in vivo studies did not suggest that ronidazole would be mutagenic for the mammal. Ronidazole at concentrations of 10 and 50 mug/plate was found to increase the number of back mutations of missense mutants in the in vitro bacterial test. This finding confirms the results of Voogd et al. [19]. Incorporation of the microsomal activation system had no effect on the mutagenic capability of the test compound. In conclusion, although ronidazole was shown to be mutagenic in in vitro bacterial systems, the in vivo systems did not suggest that the compound would be mutagenic for the mammal.

Animals↗