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Biomedical subjects

S Dally

Publications and source records attributed to S Dally.

At least 19 recordsLinked to original sources

Subclinical impairment of colour vision among workers exposed to styrene.

The effects of exposure to styrene were studied among 60 men aged 20 to 56 (mean 29.5) employed in shipbuilding. Exposure was due to the handling of glass reinforced polyester materials. The study was cross sectional and the workers were compared with a control group matched for age, social and occupational state, and ethnic origin. During the study, the mean atmospheric exposure to styrene was 24.3 ppm. Mean urinary elimination was 230 mg/g creatinine for mandelic acid and 57.4 mg/g creatinine for phenylglyoxylic acid. The Farnsworth 100 hue test showed no significant differences between the exposed and control groups for error scores. A significant difference was found, however, for the number of subjects with errors axis in the red-green, or blue-yellow ranges, or both, which was larger among the exposed workers (32/60 v 20/60 for the controls (p < 0.05)). Psychometric tests were also conducted, using the World Health Organisation (WHO) neurobehavioural core test battery. Of the seven tests it included, anomalies were only found for the aiming test. These results suggest that exposure to moderate styrene concentrations of the order of 25 ppm can lead to impairment of colour vision.

Adult

Emmetropisation, squint, and reduced visual acuity after treatment.

In a sample of children used to assess the value of optical correction of hypermetropia from the age of 6 months the refraction of the most hypermetropic meridian frequently became less than 3.5 D as the children grew. When this occurred, the incidence of squint was significantly less (p less than 0.001) and the last known acuity after treatment was significantly better (p less than 0.001) than when it did not. This process of emmetropisation appears to have been impeded by the consistent wearing of hypermetropic spectacle correction from the age of 6 months.

Eyeglasses

Effect of abstinence from alcohol on the depression of glutathione peroxidase activity and selenium and vitamin E levels in chronic alcoholic patients.

Glutathione peroxidase activity and selenium and vitamin E levels were measured in the plasma and erythrocytes of 25 chronic alcoholic patients without liver cirrhosis before and after 14 days of abstinence from alcohol, and compared with the levels in 25 sex- and age-matched healthy controls. Before abstinence, all three levels were shown significantly depressed in the alcoholic patients compared with the controls, in both plasma (80, 71, and 89% of control values) and erythrocytes (68, 70, and 83% of control values). After a 14-day abstinence period with no dietary supplementation, a trend towards normalization was noted in erythrocyte (vitamin E and glutathione peroxidase 74 and 91% of control values respectively), in whole blood selenium (82%) and plasma in vitamin E (74%). However, plasma selenium and glutathione peroxidase values were lower than pre-abstinence values (76% and 86% of control values respectively). Our results point to a deficiency in the antioxidant defense system of chronic alcoholics before the occurrence of severe liver disease. This lack of protection against lipoperoxides is all the more important in circumstances like chronic alcohol consumption, in which lipid peroxidation is known to increase. However, the present study also demonstrated that during 14 days of a normal diet free of ethanol, a rapid trend occurred towards the normalization of the factors.

Adult

Factors relating to visual acuity in children who have been treated for convergent squint.

Retrospective analysis of a selected sample of children who presented with convergent squint has shown that abnormal meridional hypermetropia (3.5 D or more) at age 1 was the principal factor associated with severe amblyopia (6/24 or less) remaining after conventional treatment. Neither the reported age of onset nor delay in presentation influenced the final visual outcome.

Amblyopia

Results of a randomised trial of treating abnormal hypermetropia from the age of 6 months.

Children who were abnormally hypermetropic at the age of 6 months were randomly allocated treatment with spectacles or no treatment. The eventual incidence of squint was the same in both groups (approximately 24%). The last known visual acuity of the two groups was not significantly different either. Therefore there is no indication to screen infants with a view to preventing squint/amblyopia by optical correction of hypermetropia. If, however, the children allocated treatment are divided into two subgroups--those who wore glasses consistently and those who probably or certainly did not do so--the incidence of squint was the same, but the last known acuities of those who consistently wore glasses may be better than those who did not do so. This suggests that it may yet prove possible to prevent severe amblyopia.

Eyeglasses

Sensory and cognitive event related potentials in workers chronically exposed to solvents.

To obtain objective measures of possible impairment due to organic solvents, auditory, visual and somatosensory evoked potentials and cognitive event related potentials were recorded in a group of 13 workers occupationally exposed to a mixture of various solvents. The patients were compared to healthy subjects and to chronic alcoholics seen during post-alcohol withdrawal. Auditory and visual evoked potentials were almost normal but somatosensory evoked potentials showed a slight decrease of peripheral conduction velocities and an increase of central conduction times more marked in the solvent exposed workers who were also alcoholics. The late "cognitive" components reflecting attention processes (N2 and P3) were normal. Solvent-exposed workers and alcoholics were both characterized by some difficulty in modulating their attentional resources according to task demands, as reflected by a tendency to responses (N1, N2 and P3) of similar amplitudes whether the stimulus was or was not the target. These findings support the presence, in solvent exposed workers, of minor dysfunction of the nervous system at both peripheral and cortical levels potentiated by alcohol as well as of mild cognitive impairments concerning attention processes.

Adult

High blood lead level in alcoholics: wine vs. beer.

One hundred and sixty one alcoholics (121 men and 40 women) were studied during a social rehabilitation program. All had a daily intake of ethanol higher than 1 g/kg/day. The mean lead blood level was 28 micrograms/100 ml and was as high as 72.5 micrograms/100 ml in one subject. Wine drinkers had a higher blood lead level (29.8 micrograms/100 ml) than beer or spirit drinkers (23.8 micrograms/100 ml). A significant correlation was found between the blood lead level and systolic and diastolic arterial blood pressure and this relation was independent of sex, weight or age. We conclude that a high blood lead level can be a risk factor for hypertension in alcoholics.

Adult

[Presence of benzodiazepines in the serum of patients after accidents. Relation to alcoholism].

In a study of 2.021 injured persons (accidents at home or at work, road accidents), qualitative assays of serum benzodiazepines by the EMIT method were positive in 9.6 per cent of the cases, including 3.2 per cent who had blood alcohol levels in excess of 0.10 g/l. Benzodiazepines were more frequently found in accidents at home and on roads than in accidents at work. These results raise the question of the role played by benzodiazepines as a possible risk factor of accidents, notably road accidents.

Accidents

Detection of blood benzodiazepines in injured people. Relationship with alcoholism.

In 2021 accident victims (household, work and road accidents) the qualitative test for benzodiazepines in the serum by the EMIT method was positive in 9.6% of cases, including 3.2% of subjects who also had a blood alcohol level greater than 0.10 milligram. Benzodiazepines were detected with a particularly high frequency in household accidents and road accidents and rarely in work accidents. These results raise the problem of the role of benzodiazepines as a possible risk factor for accidents, particularly road accidents.

Accidents

Effects of lead and mercury intoxications on evoked potentials.

Pattern reversal, brain stem auditory and somatosensory evoked potentials (PREPs, BAEPs, SEPs) have been recorded on 13 patients occupationally exposed to inorganic lead compounds, in 9 patients occupationally or accidentally exposed to inorganic mercury compounds and in 26 chronic alcoholics. The results were compared to those of a normal control group. Peripheral conduction velocities were decreased in lead exposed workers and in alcoholics, but not modified in the mercury exposed patients. In the three exposed groups, an amplitude increase (PREPs and upper limb SEP cortical components), more important in the mercury group and an increase of central conduction time in case of lower limb stimulation, could be interpreted as early signs of nervous cortical impairment.

Adult

[Increase of blood lead in alcoholism. Relation with blood pressure].

Blood lead levels and blood pressure were measured on admission in 161 chronic alcoholic patients (121 men and 40 women) hospitalized for detoxification. The mean lead level was 280 micrograms/l and the highest value, in one patient, was 725 micrograms/l. These figures were as high as those of subjects under occupational exposure to lead. Blood lead level was correlated with blood pressure, and the statistical correlation appeared to be independent. Blood lead level was also correlated with serum gamma-glutamyl-transferase concentration and with the mean corpuscular volume. Wine drinkers had higher blood lead level than beer and/or liquor drinkers (mean: 298 micrograms/l versus 225 micrograms/l respectively), which fits with the higher lead content of wine.

Adult

Prediction of amblyopia and squint by means of refraction at age 1 year.

In this series amblyopia, uncorrectable by spectacles and occlusion, was highly likely (48%) if a child had +3.50 or more dioptres of meridional hypermetropia at age 1 year. 45% of children with this refraction also had a squint. All those who remained with severely defective acuity in spite of treatment had either +3.50 or more dioptres of meridional hypermetropia or 4 or more dioptres of meridional myopia at age 1 year. These children were identifiable in the 3.7% of the population at age 1 year who showed high refractive errors. Squint as such was not so accurately predictable. Of those children with squint 71% had less than +3.50 dioptres of meridional hypermetropia at age 1 year--an incidence of 4.4% of the population. Apart from two 'congenital myopes' only 16% of these had residual amblyopia after treatment, and their last known acuity was never less than 6/12. Astigmatism in infancy or later is not significantly associated with squint or amblyopia.

Amblyopia