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Biomedical subjects

R Plass

Publications and source records attributed to R Plass.

At least 55 records · Page 3Linked to original sources
PubMed1984

[Transformation reactions of special metals in organisms and in the environment. 3. In vivo reactions between mercury II chloride and monomethyltin trichloride in rats].

Following the comments on the metabolism and the toxicity of methylmercury compounds as well as on the interaction with food components and a few environmental chemicals from literature study, the results of the in vivo experiments for examining the reaction between HgCl2 and CH3SnCl3 in the gastrointestinal tract and the subsequent distribution of the formed methylmercury are reported. The reaction between both of the substances proceeding in aqueous solution with immediate formation of methylmercury also leads in the intestinal tract very rapidly to the formation of methylmercury and its distribution into various organs. An increase in the relative weight of liver and kidneys was evident.

Animals↗
PubMed1984

Contrasting effects of ethylenethiourea on hepatic monooxygenases in rats and mice.

The effects of ethylenethiourea (ETU) on the hepatic xenobiotic metabolizing system in rats and mice were investigated. Male rats and male mice were given oral doses of 50 and 75, or 50, 75, 100, 500, and 1,000 mg/kg for 3 days. The microsomal enzymes studied were aminopyrine N-demethylase, aniline hydroxylase, and cytochrome P-450. In rats, the activity of aminopyrine N-demethylase was reduced to values between 60 and 70% of controls 24 h after treatment. A decrease in aniline hydroxylase activity and cytochrome P-450 content was observed on the 3rd day after exposure. In mice, treatment with ETU resulted in an increase of cytochrome P-450 at all dose levels. The activity of aniline hydroxylase was significantly elevated in the groups receiving doses of 100 mg/kg and higher. Aminopyrine N-demethylase was unaffected by the treatment. The results suggest that there are qualitative differences between rats and mice after ETU exposure with respect to the response of the hepatic mono-oxygenases.

Aminopyrine N-Demethylase↗
PubMed1981

[Significance and importance of enzyme diagnosis in the framework of toxicological studies of plant protectives, pesticides and agents for biological process control].

In toxicological experimentation, clinico-chemical and biochemical data are increasingly involved in the comprehensive evaluation of adverse effects of plant protectives, pesticides and agents for the biological process control on the mammalian organism. Blood serum and urine or organic homogenates from experimental animals kept under standardized conditions are chiefly used for enzymodiagnostic analyses. Changes in enzyme activity occurring under the influence of the bioactive test substances must be regarded as indicative of direct effects on the biocatalyst, metabolic changes or impairments of certain organs.

Animals↗
PubMed1980

[Synergism of selected pesticides. 1. Acute oral toxicity in combined administration].

Comparative studies with male rats were performed to investigate the coergism of single oral doses of selected pesticides, the comparison being based on the lethal effects observed. The quantitative analysis of the dose-mortality relationship and the determination of the coergistic index evidenced a slight increase of the lethal effect with lindane-phosmet and lindane-carbaryl combinations. The combined administration of lindane and ethylenethiourea resulted in an additive lethal effect.

Animals↗
PubMed1980

[Effect of cadmium on the microsomal liver enzymes of the rat].

Action of cadmium on microsomal liver enzymes of rat was tested by determination of aniline-hydroxylase and aminopyrine-N-demethylase activities as well as of the cytochrome-P-450 level and measurement of hexobarbital sleep. Rats which had 0.88 mg/kg body weight, 4.4 mg/kg, and 8.8 mg/kg cadmium chloride (CdCl2) orally applied exhibited significant stimulation of aniline-hydroxylase on the first day following application. That stimulation effect remained to be detectable from the group with the highest cadmium dose on the third and even seventh days from application. Aminopyrine-N-demethylase activities were changed by differentiated patterns under the above conditions. Cytochrome-P-450 levels in liver microsomes went down after one single oral application of cadmium chloride. Hexobarbital sleep was prolonged with significance in rats, one day after oral application of 8.8 mg CdCl2/kg body weight. The effects on the above liver enzymes produced by CdCl2 administration in drinking water were identical with those following the above oral application. However, the differences were less strongly pronounced, and hexobarbital sleep was not affected at all.

Administration, Oral↗
PubMed1978

[The effect of ethylenethiorea on microsomal liver enzymes in the rat].

The effect of ethylene thiourea on microsomal liver enzymes of rat has been studied by measuring hexobarbital sleeping time and determining aminopyrine-N-demethylase and aniline-hydroxilase activities. Single oral doses of 50, 100 and 200 mg/kg body mass caused significant prolongation of the sleeping time in males. The same effect was caused by 200 mg/kg in females. When ethylene thiourea was administered in the diet at a level of 200 ppm sleeping time in males increased with duration of administration. The duration of narcosis of females increased up to the third week and remained almost constand over the following feeding period. The aminopyrine-N-demethylase and aniline-hydroxylase activities in the liver of male rats were inhibited by single doses of 20 mg/kg or more. Inhibition and subsequent enzyme change depended on dosage.

Aminopyrine N-Demethylase↗
PubMed1976

The metabolism of lindance and its metabolites gamma-2,3,4,5,6-pentachlorocyclohexene, pentachlorobenzene, and pentachlorophenol in rats and the pathways of lindance metabolism.

The metabolism of lindane and its metabolites, gamma-PCCH, PCB, and PCP, has been studied in rats. Urine, faeces, blood and important organs were analyzed for free metabolities and those bound as beta-glucuronides. TeCCOL was identified as a main metabolite by GC/MS and gamma-PCCH has been evaluated toxicologically. A degradation scheme, based on experimental results and comprising only one hypothetical metabolite is proposed and discussed.

Animals↗