The relationship between manganism and the workplace environment in China.

Manganese is a trace element and a cofactor of many enzymes, so it is essential for physiologic functioning, but it is also a neurotoxin at high doses. Manganism is most often caused by occupational exposure. It is manifested by a myriad of signs and symptoms ranging from the neurasthenia syndrome, such as headache and dizziness, to the Parkinson-like syndrome, depending on the blood manganese levels as well as the duration of exposure. We are reporting a case of manganism using both clinical and occupational hygiene investigation methods. The patient presented the neurasthenia syndrome accompanied by hypertonicity of arm muscles and was diagnosed to have mild chronic manganism. Finally, the patient was discharged from the hospital after the treatment had improved her condition. In China, there are many chronic manganese cases, partly due to a rapid industrial development with great use of Mn and the low self-protection awareness among the workers and the factories management that cannot catch up with the speed of the economical development. Therefore, factories are responsible for improving the conditions at the workplace.

Neurotoxic effects in workers of the clinical thermometer manufacture plant.

OBJECTIVES: Occupational exposure to mercury can induce adverse health effects, and the central nervous system is the major target of its toxic action. This problem especially arises in plants involved in the manufacture of mercury-containing products, where an appropriate protection against mercury exposure is not ensured. The aim of this study was to assess health effects of mercury, especially neurotoxic effects and oral disorders, in workers employed in a clinical thermometer manufacture plant and to determine mercury concentrations in the workplace ambient air. MATERIALS AND METHODS: The study population comprised 143 workers, including 51 (35.7%) men and 92 (64.3%) women employed in the plant. Mean age in the whole group was 29 years (range, 18-55 years). It was divided into three groups: control, mercury absorption and mercury poisoning. A questionnaire-based interview was used to collect data on medical history, occupational exposure and employment. For clinical diagnosis, all subjects underwent physical, neurological and oral examinations. Mercury concentrations in the air were recorded by Hg monitoring instrument and mercury levels in collected urine samples were determined by cold vapor atomic absorption spectrophotometry. RESULTS: Neurasthenic symptoms were found in 51.75% of the subjects, emotional changes in 27.27%, tremors in 11.19%, and inflammations in 21.68%. The case percentage of neurological symptoms in the control and mercury absorption groups did not show significant difference, but it was significantly higher in the mercury poisoning group. CONCLUSIONS: The high occupational exposure to mercury, found in the plant and evidenced by urinary Hg concentration > or = 0.05 mg/l, can result in chronic quantitative neurotoxic effects and qualitative health changes. Therefore, constant monitoring of the work environment and checking of workers' health status should be ensured. In addition, appropriate steps should be taken to improve work conditions and promote health among the employees.

[Psychoemotional disorders in those working with epoxy compounds]. / Psikhoémotsional'nye rasstroistva u rabotaiushchikh s époksidnymi soedineniiami.

Psychoemotional status was studied in 125 female workers 21 to 50 years old having been exposed to epoxide resins and their compounds for 5 to 25 years. We undertook to carry out multifactor questionnaire survey together with pathopsychological testing, and determining levels of personal constitutional and reactive anxiety. Occupation-related neurotic disorders (neurasthenic-, obsessive and phobic-, and, to a lesser extent, hysterical type manifestations) were found out to develop during the stage of prenosologic forms against the background of high level of both constitutional and reactive anxiety. It is psychoconstitutional traits of workers being predisposing factors for the disorders in question that affect the epoxide-related origination and development of psychoemotional derangement. The following traits can be regarded as predisposing factors for derangement: excitability, bias towards anxiety, deestiming, demonstrable behaviour.

Alterations in heart rate and pupillary response in persons with organic solvent exposure.

Cardiac and pupillary reactivity were examined in 25 persons with a history of exposure to organic solvents and 19 nonexposed controls during performance of a counting and a choice reaction task. The solvent-exposed group demonstrated an atypical pattern of responding across tasks. While control subjects showed a decline in heart rate across the two conditions (e.g., habituation), exposed persons had an increase in heart rate. Initial pupil diameter was similar for both groups, but only the control subjects exhibited habituation across the two tasks. In the exposed group, higher heart rate was not associated with higher levels of self-reported anxiety. Anticipatory cardiac deceleration preceding unpredictable events was significantly less in the exposed group, but there were no significant group differences on poststimulus acceleration. The results suggest that persons with solvent exposure have a deficiency in the allocation of attention (reduced anticipatory deceleration and decreased pupillary dilation). It is further suggested that difficulty in the allocation of attention produces an increase in tonic sympathetic levels when confronted with a cognitively challenging task. In this experiment, in which the choice reaction task was purposely presented last, and was apparently more challenging for exposed persons, a failure to exhibit autonomic habituation over the course of the session characterized the solvent-exposed group.

Neurasthenic fatigue, chemical sensitivity and GABAa receptor toxins.

Following observation of fatigue syndromes in people who have been occupationally exposed to pesticides and insecticides which exert their toxicity through the GABAa receptor, we have formulated the hypothesis that fatigue syndromes in general may be secondary to altered sensitivity of the GABAa receptor. We discuss the possible involvement of organochlorine compounds which are widespread in the environment. Organophosphate compounds may have similar toxic effects through damaged cholinergic input to the dentate gyrus of the hippocampus where cholinergic and GABAergic transmission are closely linked.

[Health effects on workers exposed to low concentration carbon monoxide at high altitude].

Workers exposed to carbon monoxide (CO) at a concentration of 26.8mg/m3 at an altitude of 2,300 metres above sea level were compared with a control group of local inhabitants. There were significant differences in symptoms of headache, vertige fatigue and weakness memory impairment, insomnia, palpitation and neurobehavioral functions. CO concentration in respiratory air and HbCO in blood was higher but partial pressure of oxygen (PO2) and saturation of oxygen (SaO2) in blood was lower in the exposed group than the control group. Self-comparison of CO in respiratory air and HbCO in blood was higher after work than before work. Neurasthenia rate was significantly higher but PO2 and SaO2 significantly lower at high altitude than in the plain. The results indicated that under same CO concentrations the hazards to workers at high altitude were greater than to those working in the plain. The author recommends that at high altitude the CO permissible level should be appropriately lowered.

Dose-related subclinical neurobehavioral effects of chronic exposure to low levels of organic solvents.

One hundred eight-seven workers (mean age +/- SD; 42 +/- 8.8 years) in two paint manufacturing plants were examined to determine if sustained low-level exposure to mixed organic solvents resulted in the painters' syndrome (a psycho-organic syndrome). The test battery consisted of a medical and occupational questionnaire, the Present State Examination, the Zung Depression Scale, the Scandinavian Questionnaire 16, a neuropsychological battery, and vibration thresholds. Solvent exposure, expressed as total hydrocarbon of combined selected solvents, was quantitated using 13-15 years of personal breathing zone samplings. Linear regression analysis controlling for several confounding variables demonstrated significant correlations between increasing exposure to mixed organic solvents and neurobehavioral performance for vibration threshold and several neuropsychological tests. Dose-related effects of chronic solvent exposure on neurobehavioral outcomes (all subclinical) were shown, but "typical" symptoms characteristic of the painter's syndrome were not found.

Subclinical neuropsychiatric effects of chronic low-level solvent exposure in US paint manufacturers.

In the present study, 187 workers at two US paint manufacturing plants were assessed for symptoms of painters syndrome using the Zung Depression Index, Scandinavian Questionnaire 16, and the Present State Exam. No significant associations were found between solvent exposure and total scores, although a sum of individual questions related to depression on the Present State Exam was found to be related to both health status and exposure. The clinical relevance of these findings is discussed. Overall, exposure was not associated with the constellation of symptoms characteristic of the painters' syndrome.

Neuropsychiatric effects of low exposure to styrene.

Workers exposed to styrene concentrations of about 50 mg/m3 at a plant manufacturing reinforced polyester boats were examined for neuropsychiatric symptoms both in close connection with exposure and also seven months after exposure had ceased. Physical workload is important for the uptake of styrene and was about 50 W at this plant. On the first occasion, after one week with no exposure, the workers reported a high frequency of neuropsychiatric symptoms such as fatigue, irritation, and forgetfulness whereas seven months later the frequency of these symptoms was low. These observations indicate that exposure to styrene at about 50 mg/m3 may induce reversible neuraesthenic symptoms. Even the relatively low Swedish standard (110 mg/m3 = 25 ppm) may, therefore, need revising.

Prenarcotic and neuraesthenic symptoms among Dutch workers exposed to organic solvents.

A population of 379 Dutch workers exposed to organic solvents was compared with a non-exposed population of 443 workers with regard to the prevalence of prenarcotic and neuraesthenic symptoms. Participants completed a questionnaire to collect information about their occupational history, exposure to organic solvents, and the occurrence of symptoms. The results of the study indicated that workers exposed to solvents have a higher reporting rate of prenarcotic symptoms than workers not exposed to solvents. The prevalence of chronic neurotoxic effects, however, in the form of neuraesthenic symptoms was only weakly associated with reported exposure to organic solvents. The influence of work stress in the development of these symptoms is perhaps more important than the role of exposure to organic solvents. It is concluded that the organic solvent syndrome type I, as defined by an international workshop, is not an important health hazard among Dutch painters.

Do Vietnam veterans suffer from toxic neurasthenia?

This paper evaluates the claim that Vietnam veterans with psychiatric disorders are suffering from toxic neurasthenia--a neurasthenic syndrome caused by exposure to pesticides while serving in Vietnam.

[State of the nervous system of workers engaged in painting with bituminous lacquers]. / Stan ukladu nerwowego pracowników zatrudnionych przy malowaniu lakierami bitumicznymi.

The neurological and electroencephalographic examinations involved a group of 82 workers dealing with the protection of railway carriage assemblies against corrosion. For anamnesis "The Höck and Hess ailments questionnaire" was used to evaluate the neurotic syndrome. The results have been compared in varnishing workers under better and worse toxicological conditions. The evaluation of the varnishing workers' nervous system did not reveal any specific clinical picture. More frequent neurotic ailments and EEG deviations in those working under worse toxicological conditions may be indicative of enhanced neurotoxic effects of organic solvents, used for lacquers dilution, upon the brain disfunction.

Effects on the regional cerebral blood flow of long-term exposure to organic solvents.

Regional cerebral blood flow (rCBF, 133Xe inhalation method) was measured in 50 male paint-factory workers with a mean of 18 years of exposure to a mixture of organic solvents. A group of 50 workers in a sugar-refinery, matched for age and education, served as controls. The measurements were made during resting and during activation by mental tasks (4%; P less than 0.05) in the exposed group. Largest differences were seen in frontotemporal areas. The difference between the exposed group and and controls increased at higher dose levels. The largest rCBF-increases during mental activation were seen in the exposed group, especially in the highest exposed subjects. This finding might indicate mechanisms compensating for a somewhat defective brain function. Although the differences between the groups were generally small with considerable overlap, the results give some evidence of disturbances of brain blood flow and brain function likely related to the influence of organic solvents.