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Biomedical subjects

N Cherry

Publications and source records attributed to N Cherry.

At least 19 recordsLinked to original sources

Neurotoxic effects of styrene: further evidence.

The relation of exposure to styrene to measures of nervous system function was investigated in 70 men working in four factories in the Montreal area of Quebec. Mild sensory nerve conduction deficits were found, the proportion with such deficits rising from 23% in those exposed to less than 50 ppm to 71% in those exposed to more than 100 ppm. Reaction time was slower for those with a larger body burden, as indicated by area under the excretion curve, and for those who failed to clear the metabolite during the weekend. No slowing in conduction time was found among a small group of five men exposed to more than 100 ppm for less than four weeks. There was some evidence that both central and peripheral slowing recovered when workers were removed from exposure. Uptake, storage, or elimination of styrene was influenced by the physical demands of the work, skinfold thickness, cumulative exposure, and alcohol consumption. Nevertheless, only the wearing of a mask and current consumption of alcohol were associated with a lower risk of sensory conduction deficit. While there was no clear indication that neurotoxic effects were related to individual differences in the capacity to metabolise high concentrations of styrene, measurement of urinary metabolites may be helpful in identifying those at highest risk.

Adolescent

Work with visual display units in pregnancy.

Data from the Montreal survey on occupational factors in pregnancy were used to test the hypothesis that visual display units (VDUs) constitute a hazard to reproduction. Use of a VDU was recorded in 4712 current and 2164 previous pregnancies of women in full time employment at time of conception. After allowance for seven confounding variables, the risk of spontaneous abortion in current pregnancies relative to all working women was 1.19 (90% CI 1.09-1.30) and in previous pregnancies, 0.97. In an analysis by occupational title, in which 60 occupational groups were aggregated into eight categories according to use of VDUs, the relative risk for spontaneous abortion was 1.06 (90% CI 0.8-1.4) in current pregnancies and 1.01 (90% CI 0.7-1.3) in previous pregnancies. This suggests that the small excess of spontaneous abortions among individual women reporting the use of VDUs in current pregnancies may have been due to recall bias. Relative risks for stillbirth, preterm birth, and low birth weight all had 90% confidence limits which included unity. In an analysis of congenital defects the number of pregnancies was increased to include women who worked 15 or more hours a week. In all but one of nine groups of congenital defect examined confidence limits for the relative risk included unity in both current and previous pregnancies. The relative risks for the renal urinary group of defects were raised in both current (1.84, 90% CI 1.07-3.15) and previous pregnancies (1.66, 90% CI 0.82-3.25). There being no prior reason to suspect a causal link with this type of defect, interpretation remains open to question.

Abortion, Spontaneous

Occupation and pregnancy outcome.

Over a two year period, 1982-4, 56067 women, delivered or treated for a spontaneous abortion in 11 Montreal hospitals covering 90% of such admissions, were interviewed in detail regarding their occupational, social, and personal characteristics in their most recent and past pregnancies--104,649 in all. These data were analysed in relation to four main adverse outcomes--spontaneous abortion, stillbirth (without defect), congenital defect, and low birth weight (less than or equal to 2500 g). For comparison with observed numbers, expected figures were calculated by logistic regression using up to eight potentially confounding variables. Sixty occupational groups in six main industrial sectors were examined in current and previous pregnancies, with tests for heterogeneity between these two estimates of risk. Women in managerial, health, and clerical sectors had little evidence of excess of any of the four outcomes, by contrast with those in sales, service, and manufacturing sectors. Substantial and statistically significant excesses of spontaneous abortion were observed in nursing aides, women in sales occupations and food and beverage service; of stillbirth in agriculture and horticulture, leatherwork, and certain sales occupations; of congenital defects in women in child care, certain service occupations, and the manufacture of metal and electrical goods; and of low birth weight in chambermaids, cleaners, and janitors, and in women employed in the manufacture of food and drink, metal and electrical goods, and clothing.

Abortion, Spontaneous

Neurobehavioural effects of repeated occupational exposure to toluene and paint solvents.

In studies of two workforces 44 men exposed to paint solvents and 52 men working with toluene were compared with age matched comparison groups of non-exposed workers. Scores on a series of performance tests were examined, the solvent exposed in each study functioning less well than their comparison group. The apparent deficit among the paint exposed workers was substantial, but this was reduced after allowance for estimated intellectual capacity. No deficit was apparent on rematching with a second comparison group of more appropriate measured capacity. No evidence was found of impaired nerve conduction in the ulnar or median nerves, and few clinical signs of neurological damage were apparent. Nevertheless, in an associated inquiry of neuropsychological symptoms among 236 painters and 128 non-exposed workers a highly significant excess of symptoms was found among those exposed to paint solvents.

Adult

The prevalence of psychiatric morbidity in solvent workers in Britain.

Using data originally collected in Britain as part of the study of morbidity in general practice in 1970-71, we have made an estimate of the prevalence of minor psychiatric illness amongst workers exposed to organic solvents. No differences were found between the rates of consultation for mental illness in any solvent exposed group either male or female. Nor was any difference found in the prevalence of mental illness found between workers exposed to solvents and non-exposed referents when we examined data from two smaller studies.

Adolescent

The effects of ethanol on blood toluene concentrations.

The metabolism of toluene was found to be inhibited by a large dose of alcohol in seven volunteers exposed to 80 ppm of toluene under experimental conditions. When alcohol was taken during exposure, blood toluene concentrations were 42.5% greater on average than during exposure with no alcohol. This is probably due to competition for alcohol dehydrogenase which is required for the breakdown of both ethanol and toluene. In men exposed to toluene at work, it was found that blood toluene concentrations were lowest in those who drank regularly. These results suggest that continued alcohol intake increases the metabolism of toluene, presumably by inducing the microsomal oxidising enzyme system in the liver.

Adult

Effects of trace levels of nitrous oxide on psychomotor performance.

Twenty-four male student volunteers were exposed to 50 ppm of nitrous oxide or air in an exposure chamber for 4 h in two experimental sessions. The subjects completed a battery of psychomotor tests during the final 40 min of the exposure sessions. Nitrous oxide, at this low concentration, did not produce any statistically significant changes in performance.

Acoustic Stimulation