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Biomedical subjects

H Vainio

Publications and source records attributed to H Vainio.

At least 289 records · Page 16Linked to original sources

Mutagenicity in urine of workers in rubber industry.

Epidemiological studies have shown that those who work in rubber industry have an increased risk of cancer. In the working environment they are exposed, probably, to several hundred different chemicals some of them being known or suspected carcinogens and mutagens. The bacterial fluctuation test was used to detect the mutagenicity in the urines of exposed workers. A group of unexposed office clerks served as controls. Both groups consisted of smokers and non-smokers, and that was taken into consideration in the results. Rubber workers, either smokers or non-smokers, exhibited significantly higher mutagenic activity in their urine than the occupationally unexposed controls when the base-pair substitution strain E. coli WP2 uvrA was used as indicator organism. Use of the frameshift strain S. typhimurium TA98 revealed increased mutagenicity in the urine of occupationally exposed smokers, nonsmokers and unexposed smokers. The extent of mutagenicity in the urine of workers who smoked suggested a synergistic effect of smoking and occupational exposure. The bacterial fluctuation test with urine samples as sources of mutagenicity is able to detect chemical exposure if the excreted compounds are still in active form or can be activated. The method can be used to identify hazardous working conditions long before the manifestation of possible pathological changes in exposed individuals.

Escherichia coli↗

Dose-related hepatotoxicity of 1,1,2-trichloro-1,2,2-trifluoroethane in short-term intermittent inhalation exposure in rats.

Male Wistar rats were exposed to 200, 1000 or 2000 ppm of 1,1,2-trichloro-1,2,2-trifluoroethane vapor 5 days a week 6 h daily for 1 or 2 weeks. Proliferation and vacuolisation of the smooth endoplasmic reticulum (SER) of the liver was seen electron microscopically after 1 and 2 weeks in the rats exposed to 1000 and 2000 ppm. Among the hepatic drug metabolizing enzymes, NADPH cytochrome c reductase activity showed a dose-related decrease whereas the tightly membrane-bound UDPglucuronosyltransferase exhibited a dose-dependent enhancement in its measurable activity. The overall drug oxidation reaction, 7-ethoxycoumarin O-deethylase was not affected by the 1,1,2-trichloro-1,2,2,-trifluoroethane inhalation at all, either in the liver or in the kidneys. 1,1,2-Trichloro-1,2,2-trifluoroethane binds to cytochrome P-450 with the production of a type I difference spectrum, suggesting that it may act as a substrate for this enzyme. The binding affinity is increased by phenobarbital-treatment of the rats.

Animals↗

Chromosomal aberrations in bone marrow of Chinese hamsters exposed to styrene and ethanol.

No significant increase was detected in the number of chromosomally damaged cells in bone marrow of Chinese hamsters after either inhalation exposure to 300 ppm styrene or oral intake of 15% ethanol in drinking water (exposure time 4 days or 3 weeks). In combined exposure, a slight increase of chromosomal aberrations was observed in the group exposed for 4 days (2.0% aberrant cells vs. 0.0% in controls). The group exposed for 3 weeks to combined treatment showed no response (0.3% aberrant cells vs. 0.7% in controls).

Animals↗

Inability of styrene to induce nondisjunction in Drosophila or a positive micronucleus test in the Chinese hamster.

Styrene produced no effect on induction of sex-chromosome nondisjunction in Drosophila melanogaster fed on 500 ppm styrene for 24 h. No increase in the frequency of micronuclei from chromosome fragments or from nondisjunction of whole chromosomes was seen in the bone marrow of Chinese hamsters (Cricetulus griseus) injected (i.p.) with a single dose of 1.0 g/kg b.wt. styrene or with 250 mg/kg b.wt. of the primary metabolite, styrene oxide.

Animals↗

Styrene and styrene oxide induce SCEs and are metabolised in human lymphocyte cultures.

Both styrene and its presumed active metabolite styrene oxide show dose response as potent inducers of sister chromatid exchanges (SCEs) in human lymphocyte cultures. The SCE inducing and clastogenic capacity of styrene in lymphocytes in vitro can be explained by gas chromatographically measurable increase of styrene oxide in styrene treated cultures.

Biotransformation↗

Spontaneous abortions by occupation and social class in Finland.

A hospital discharge registry covering all general hospitals in Finland was used in the study of spontaneous abortions. Spontaneous abortions were analysed by the women's occupation and socio-economic class for 1973-75 inclusive. The risk of spontaneous abortion increased from social class 1 to 4 by about 50%. The occupational groups with an increased frequency of spontaneous abortions included industrial and construction work, agriculture, forestry and fishing, sales, transport and communication, services, and students and trainees. Decreased frequency of spontaneous abortions was noted among housewives, and in managerial and clerical occupations. The results suggest that socio-economic factors contribute to the rate of spontaneous abortions analogous to their known adverse effects on pre-term birth, birth weight and perinatal mortality.

Abortion, Spontaneous↗

The effect of maternally inhaled styrene on embryonal and foetal development in mice and Chinese hamsters.

Pregnant mice and Chinese hamsters were exposed to styrene 6 hrs daily during the period of major organogenesis via inhalation in concentrations 250 p.p.m., and 300, 500, 750 and 1000 p.p.m., respectively. Both in mice and in Chinese hamsters embryotoxicity was raised. Some minor skeletal malformations (rib fusions, extra ribs) were noted in mice but not in Chinese hamsters.

Animals↗

Enhancement of hepatic drug biotransformation by a short-term intermittent turpentine exposure in the rat.

An inhalation exposure of male rats to 300 p.p.m. of a commercial turpentine 6 hrs daily 5 days a week for 8 weeks enhanced the activities of drug biotransformation enzymes of liver microsomes considerably. The activities of NADPH cytochrome c reductase and 7-ethoxycoumarin deethylase, and microsomal content of cytochrome P-450 were increased 35-60% during the first weeks of the experiment, but had a tendency to return towards the control values later on. A similar enhancement of activities was also found in liver microsomal epoxide hydratase and UDP glucuronosyltransferase, but these enzyme activities tended to adapt less during the experiment. The turpentine treatment increased the affinity of liver microsomal cytochrome P-450 to alpha-pinene (the main component of the turpentine). The present data suggests that exposure to turpentine is able to modify considerably the biotransformation of drugs.

7-Alkoxycoumarin O-Dealkylase↗

The combined toxicity of technical grade xylene and ethanol in the rat.

1. Inhalation exposure to xylene of technical grade (300 p.p.m. in air, 6 h a day, 5 days a week, up to 18 weeks) enhanced the overall mono-oxygenation reactions (7-ethoxycoumarin O-deethylase and 2,5-diphenyloxazole hydroxylase( as well as the UDP-glucuronyltransferase activity in rat liver microsomes. 2. The simultaneous ingestion of aqueous 15-20% ethanol as drinking fluid increased the cytochrome P-450 concn. and the mono-oxygenation activity even more than the xylene exposure alone. 3. Xylene-ethanol treatment resulted in additive or less than additive effects on the measured hepatic enzyme activities. 4. Renal ethoxycoumarin deethylase activity was enhanced both by ethanol ingestion and by xylene inhalation, and the response was additive after the combined exposure. 5. Liver histology revealed that even though the xylene exposure alone did not produce detectable liver damage, the xylene-ethanol treatment produced more severe liver damage than did ethanol ingestion alone.

Animals↗

Increased sister chromatid exchange frequencies in lymphocytes of nurses handling cytostatic drugs.

In oncology units, personnel handling chemotherapeutic drugs may occasionally be exposed to small amounts of genotoxic agents. This exposure was obviously the cause of the increased frequencies of sister chromatid exchange (SCE) observed in nurses in daily contact with cytostatics (N = 20, mean SCEs/cell +/- SE 9.4 +/- 0.3) as compared to a group of office workers (N = 10, mean SCEs/cell 8.1 +/- 0.3). The oncology nurses also had a higher SCE frequency than other hospital nurses (N = 10, mean SCEs/cell 8.7 +/- 0.2), but this difference was not statistically significant. The SCEs of patients under chemotherapy were about five times higher (mean SCEs/cell 36.8 +/- 0.6) than those of healthy subjects.

Antineoplastic Agents↗

[Dioxins].

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Animals↗

Effects of subacute toluene inhalation on its metabolism and disposition in rat.

Exposure of adult male rats to 300 ppm of toluene for 1 to 15 weeks 6 h daily caused accumulation of the solvent in brain and in perirenal fat. The body solvent content tended to decrease during extended exposure which might be explained by the enhanced activity of drug-metabolizing enzymes in liver. Our findings also indicate that metabolic and functional adaptation takes place in longer exposures to low levels of toluene vapour.

Adipose Tissue↗