[Occupational diseases of the nervous system caused by chemicals].
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Air Pollutants, Occupational↗
Biomedical subjects
G Triebig
Publications and source records attributed to G Triebig.
The ototoxicity of styrene: a review of occupational investigations.
OBJECTIVES: The objective of this study was to review critically a number of occupational investigations of the exposure and effect relation between inhaled styrene vapour and hearing loss. There is concern that workers' hearing may be impaired by exposure to styrene, as used in industries making plastics and fibreglass-reinforced products. METHODS: Seven occupational studies, each dealing with the ototoxicity of styrene, were examined. Factors assessed included the experimental design and number of subjects within exposure groups, measurement of the styrene-in-air concentration, confirmation of the styrene exposure by blood or urine analysis, determination of the hearing threshold levels for the exposure and control groups, and measurement of any occupational noise in the subjects' workplaces. Consideration was also given to statistical relations between high-frequency hearing loss and lifetime exposure indices for styrene and noise. RESULTS: The results are equivocal. Four investigations failed to find any effect of styrene on hearing thresholds. In contrast, other investigations claimed to have demonstrated styrene-induced hearing loss in industrial populations, with synergism between styrene and noise. However, these reports exhibited shortcomings of experimental design and data analysis. CONCLUSIONS: Considering the body of evidence as a whole, hearing deficits due to occupational exposure to styrene at low concentrations have not been demonstrated by scientifically reliable argument. There is some suggestion of an association between styrene exposure, occupational noise, and hearing dysfunction. Further studies in humans are necessary to clarify this question.
Denmark↗
[Occupational aziridine asthma in an engineer at a printing office].
We report on a case of an allergic bronchial asthma of an engineer in a printing office caused by polyfunctional aziridines. The causal relationship between exposure and symptoms could be demonstrated with a specific bronchoprovocation challenge testing. The consequences of the disease are discussed with respect to medical and legal aspects of the system of social security in Germany.
Adult↗
Chemosensory irritation and the setting of occupational exposure limits.
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Dose-Response Relationship, Drug↗
[Persistent chlorinated organic compounds and their relevance to environmental medicine].
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Adolescent↗
[Current aspects of hepatotoxicity in occupational medicine].
A large number of chemical agents encountered occupationally are known as potential hepatotoxins. The practical relevance of these results should be considered critically for the individual case and under usual work layout. In this paper the current state of knowledge for hepatotoxicity in occupational medicine is described. Different diagnostical methods and criteria for suspected chemical-induced liver injury are shown. The paper focuses on the potential hepatotoxic effects of chronic exposures to solvents, since these substances are used in a large variety of modern places of work. On the basis of field studies in occupationally exposed workers the potential hepatotoxical effects of mixtures of solvents are discussed. Recommendations for medical surveillance places of work are proposed.
Air Pollutants, Occupational↗
Results of magnetic resonance imaging in long-term manganese dioxide-exposed workers.
Within a cross-sectional study, the neurotoxic effects of occupational exposure to manganese were examined. From a group of 90 (58 male and 32 female) workers, 11 men with long-term and high exposure to manganese dioxide (MnO2) dust were defined as exposed workers. Eleven age-matched workers of similar socioeconomic status were used as a reference group. Ambient air and biological monitoring (blood, urine, hair), clinical (Webster Rating Scale, WRS), neurophysiological (visual evoked potentials (VEP), nerve conduction velocity (NCV), electroencephalography (EEG)), and motor performance (Wiener Testsystem) examinations were performed. The pallidal index (PI), the ratio of globus pallidus to subcortical frontal white-matter signal intensity in T1-weighted magnetic resonance imaging (MRI) planes multiplied by 100, was used. For the individual body burden, manganese in blood was the most reliable biomarker. A "job-exposure matrix" for the cumulative Mn-exposure index (CEI) was calculated for each worker. The results of WRS, VEP, NCV, EEG, and motor performance tests showed no significant group differences. However, the pallidal index was increased in Mn-exposed persons. Furthermore, a statistically significant positive correlation was found between CEI and pallidal index. The results of other studies are discussed. The meaning of MRI findings for health status as well as gender-specific differences should be examined in further follow-up studies.
Adult↗
Adverse health effects related to mercury exposure from dental amalgam fillings: toxicological or psychological causes?
BACKGROUND: Possible adverse health effects due to mercury released by amalgam fillings have been discussed in several studies of patients who attribute various symptoms to the effects of amalgam fillings. No systematic relation of specific symptoms to increased mercury levels could be established in any of these studies. Thus, a psychosomatic aetiology of the complaints should be considered and psychological factors contributing to their aetiology should be identified. METHODS: A screening questionnaire was used to identify subjects who were convinced that their health had already been affected seriously by their amalgam fillings (N = 40). These amalgam sensitive subjects were compared to amalgam non-sensitive subjects (N = 43). All participants were subjected to dental, general health, toxicological and psychological examinations. RESULTS: The two groups did not differ with respect to the number of amalgam fillings, amalgam surfaces or mercury levels assessed in blood, urine or saliva. However, amalgam sensitive subjects had significantly higher symptom scores both in a screening instrument for medically unexplained somatic symptoms (SOMS) and in the SCL-90-R Somatization scale. Additionally, more subjects from this group (50% versus 4.7%) had severe somatization syndromes. With respect to psychological risk factors, amalgam sensitive subjects had a self-concept of being weak and unable to tolerate stress, more cognitions of environmental threat, and increased habitual anxiety. These psychological factors were significantly correlated with the number and intensity of the reported somatic symptoms. CONCLUSIONS: While our results do not support an organic explanation of the reported symptoms, they are well in accord with the notion of a psychological aetiology of the reported symptoms and complaints. The findings suggest that self-diagnosed 'amalgam illness' is a label for a general tendency toward somatization.
Adult↗
Intervention study on acquired color vision deficiencies in styrene-exposed workers.
The main aim of the study was to examine the possible effects of occupational exposure to styrene on color vision function and the course after reduction of exposure. Color vision function was examined in 22 styrene-exposed laminators and 11 control subjects at a boat manufacturing plant. The Lanthony D-15 desaturated panel was used to test acquired dyschromatopsia. In all, six examinations were performed: Monday morning and Thursday afternoon of the same week, before and immediately after a vacation of 4 weeks (altogether, phase 1), and approximately 10 months later (phase 2), after the exposure level of styrene had been reduced. Styrene uptake was objectified by biological monitoring measuring the metabolites mandelic acid and phenylglyoxcylic acid in urine samples taken on Thursday afternoon. In both Thursday examinations, styrene-exposed workers had higher color confusion index (CCI) values compared with controls, which indicated quantitative color vision loss. After an exposure-free period of 4 weeks, a significant decrease of CCI values to normal range was found in laminators. Reexamination 10 months later showed also lower CCI values in exposed workers, indicating a dose-effect relationship. Abnormal CCI values occurred primarily in subjects with an excretion of approximately 500 to 600 mg mandelic acid plus phenylglyoxcylic acid per gram creatinine or more. We concluded that styrene-induced color vision dysfunction is reversible after an exposure-free interval of 4 weeks. The current Biological Tolerance Value of 600 mg mandelic acid plus phenylglyoxcylic acid per gram creatinine, as used in Germany, protects styrene-exposed workers from this subclinical effect.
Adult↗
Evaluation of a modified German version of the Q16 questionnaire for neurotoxic symptoms in workers exposed to solvents.
OBJECTIVES: To assess sensitivity and specificity of a questionnaire designed to detect neurotoxic symptoms in workers exposed to solvents and in patients with a psycho-organic syndrome. METHODS: The Swedish Q16 is a self administered questionnaire for neurotoxic symptoms. The modified German version consists of 18 questions. The results were analysed from 1166 questionnaires which were completed by adults belonging to the following groups; 483 workers with occupational exposure to solvents and 193 non-exposed controls, 25 patients with a psycho-organic syndrome, 25 sex and age matched patients with a lung disease, and a sample of 440 people from the general population. RESULTS: The German Q18 was easy to handle and quick to perform. Workers exposed to solvents reported significantly more complaints than controls (2.9 v 2.5). All patients with a psycho-organic syndrome had five or more complaints. This was true for only 32% of patients with lung disease. These comparisons showed that chronic exposure to solvents was associated with subjective complaints related particularly to cognitive functions. In the sample of the general population, age, education level, smoking habits, and time of performance showed no significant influence on the Q18 result. Women had significantly more complaints than men (3.2 v 2.3). People who reported drinking alcohol occasionally or moderately had significantly fewer complaints than teetotalers. CONCLUSIONS: The German Q18 has an acceptable sensitivity and reliability, a reasonable specificity, and a good practicability. It is a useful instrument for screening workers exposed to solvents. A cut off point of 5 for men is recommended, and a cut off point of 6 for women is proposed.
Adult↗
Survey of solvent related chronic encephalopathy as an occupational disease in European countries.
OBJECTIVES: To obtain information about solvent related chronic encephalopathy (SRCE) in the countries of the European Union (EU). METHOD: A survey was conducted in 1998 and 1999 among medical experts, authorities for health and safety, and social security institutions. RESULTS: SRCE is an acknowledged occupational disease in most of the participating countries. However, the numbers of compensated cases differ considerably. This is mainly a consequence of national social law rather than of differences in the criteria of diagnosis. In countries with relatively high reported incidences-such as Denmark, Finland, Norway, and Sweden-the number of acknowledged cases has declined over the past 5-10 years, although the most important criteria of diagnosis and causality, according to expert opinion, equivalent diagnostic procedures, and measures for prevention within the EU are not comparable. CONCLUSIONS: There is a need for common guidelines for early diagnosis and the evaluation of causality. Actual figures of SRCE are not suitable to estimate prospective numbers of cases. For this reason a multicentre study in EU states is necessary after a consensus of diagnostic procedure. It is likely that the number of cases will decrease as a result of changes in legislation and preventive measures-such as substitution or reduction of solvents in the products, improvement of technical equipment, and regular health surveillance. Future research activities should focus on follow up studies of prognosis, randomised clinical trials of treatment, investigation of neurotoxic mechanisms, and of the interaction of solvent mixtures.
Europe↗
Chlorinated dibenzo-p-dioxins and dibenzofurans and the human immune system: 3. Plasma immunoglobulins and cytokines of workers with quantified moderately-increased body burdens.
The concentrations of immunoglobulins (IgA, IgD, IgG, IgM) and of several cytokines were measured in the plasma of volunteers with clearly, but moderately, increased body burdens of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/PCDF), using monoclonal antibodies and an enzyme-linked immuno-sorbant assay. Two groups of workers with different body burdens of PCDD/PCDF were studied: (trial I) persons with mainly 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), and (trial II) persons with mainly penta- and hexachlorinated dibenzofurans (P5CDF/H6CDF) in their blood fat. Including the reference group, 158 volunteers were investigated. A slight but statistically significant decrease was observed in the plasma concentration of IgG1 in persons exposed to TCDD, but not in persons exposed to P5CDF/H6CDF. When the data of both groups were pooled and a multi-regression analysis against international TCDD toxicity equivalencies (I-TEq, NATO/CCMS) was performed, taking several confounding factors into account, no influence of the dioxin exposure could be revealed. There were no changes in the plasma concentrations of the other immunoglobulins studied. In the same volunteers, no deviation from the reference range was found for the concentrations of the cytokines: IL-1alpha, IL-1beta, IL-6 and TNFalpha in blood plasma.
Adult↗
Solvent related chronic encephalopathy.
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Brain Damage, Chronic↗
[Magnetic resonance tomography of the brain in workers with chronic occupational manganese dioxide exposure].
AIM: Changes within the brain detected by MRI after chronic manganese poisoning raised the question whether morphological changes of the basal ganglia, particularly of the globus pallidus, could be detected after chronic occupational exposure to manganese dioxide. METHOD: In a cross-sectional study, healthy workers (48 male and 27 female) at a dry cell battery factory were examined. Actual internal exposure was quantified by the analysis of manganese in the blood using atomic absorption spectrometry. Chronic exposure was defined as a cumulative index (CBI) including duration of exposure, individual workplace factors, and previously measured concentrations of MnO2 in dust samples. A Philips Gyroscan T5-II (0.5 T) was used for the MRI of the brain. The following indicators were taken to ascertain possible manganese-induced changes; Pallidum-Index (PI), width of 3rd ventricle and cella media index in addition to clinical examinations. RESULTS: No cases of parkinsonism were detected in clinical examinations or by other means. The mean manganese concentration in blood was 12 micrograms/l (range: 3.9-23.3 micrograms/l). In comparison to the upper reference value of 10 micrograms/l, 42 workers (56%) had a higher body burden. A significant positive correlation between manganese levels in blood and the PI (indicated by T1-shortening) was observed as well as between the CBI and workplace-specific exposure. Brain atrophy was not detected in any of the observed cases. CONCLUSIONS: Long-term exposure to manganese dioxide dust correlates with the Pallidum-Index in MRI scans. Although the MRI findings have no current clinical relevance for individuals, further studies are necessary to evaluate specificity and potential prognostic value.
Adult↗
Neuropsychiatric symptoms in active construction painters with chronic solvent exposure.
A cross-sectional study was performed to assess whether chronic solvent exposure of painters is associated with increased neuropsychologic symptoms. 401 painters and 209 construction workers without solvent exposure, both groups with at least 10 years of employment, were subjected to extensive clinical examinations. Standardized questionnaires were used for medical and occupational history. Painters reported an excess of specific symptoms that could be assigned to mood and behaviour. The differences between specific and unspecific questionnaire outcomes as well as the positive correlation between chronic exposure index and symptom scores support the hypothesis of solvent induced effects. These symptoms are related to life-long solvent exposure rather than current exposure levels. At present the questions of time course and reversibility or irreversibility of symptoms cannot be answered. The predictive value of these symptoms for subsequent neuropsychiatric morbidity remains to be elucidated in a future follow-up study.
Adult↗
[Polyneuropathy and encephalopathy caused by organic solvents and mixed solvent solutions. Occupational medicine and neurologic aspects of a new occupational disease].
Solvent induced polyneuropathy and encephalopathy have been acknowledged quite recently as occupational diseases in Germany. For compensation first of all the diagnosis has to be proven. For differential diagnosis other known causes as well as non-organic mental diseases must be taken into consideration. The causality between proven exposures and diagnosed disease has at least to be probable. To evaluate causation extensive experience of the experts is needed. In this context scientific criteria regarding neurotoxicity of the solvent, duration of exposure, individual aspects of non-occupational influences, time course of the disease are important within a through synoptic evaluation. Possibilities and limitations of sensitive diagnostic measures such as neurographic, neuropsychologic and neuroimaging examinations are discussed. The prognosis of toxic polyneuropathy and encephalopathy is in general favorable if exposure has stopped. Additionally, adequate therapy and rehabilitation measures are supportive for a good prognosis.
Brain Damage, Chronic↗
A multidisciplinary cross-sectional study on solvent-related health effects in painters compared with construction workers.
OBJECTIVES: The main aim of the study was to examine possible solvent-associated effects on the nervous system in currently employed painters. Special attention was paid to evaluate subtle health effects. MATERIALS AND METHODS: A total of 401 painters and 209 construction workers without solvent exposure with at least 10 years of professional experience were subjected to a clinical, neurological, psychiatric, neuropsychological and neurophysiological examination. For personal medical and occupational history, standardized questionnaires were used. A quantitative rating of exposure was obtained by expert rating of the respective occupational history without knowledge of the individual test results. RESULTS: There was no excess of somatic disorders or solvent-associated adverse effects on the nervous system. No distinct effects of solvent exposure on nerve conduction velocities (NCV) or cognition were found. Discrete NCV deficits in painters were not considered a sign of subclinical polyneuropathy. Painters, however, reported an excess of specific symptoms that could be assigned to "mood and behaviour". The differences between specific and non-specific questionnaire outcomes on the one hand and the positive correlation between chronic exposure index and symptom scores on the other hand support the hypothesis of solvent-induced effects. Because data is lacking on past solvent exposure, it is not possible to relate these effects to current exposure limits. CONCLUSIONS: Currently employed painters differ from controls not exposed to solvents with respect to the frequency of certain symptoms in mood and behaviour. These symptoms are related to life-long solvent exposure rather than to current exposure. At present, the issue of time course and reversibility or irreversibility of these symptoms cannot be answered. The predictive value for subsequent neuropsychiatric morbidity remains to be elucidated in follow-up studies.
Construction Materials↗
Biomonitoring of manganese in blood, urine and axillary hair following low-dose exposure during the manufacture of dry cell batteries.
OBJECTIVES: A cross-sectional study was carried out on 100 workers from three different workplace areas in a dry cell battery manufacturing plant and on 17 currently nonexposed referents, to examine the relationship between the external exposure to manganese dioxide (MnO(2)) and the body burden of manganese in blood, urine and hair. METHODS: Inhalable dust was measured gravimetrically after stationary active sampling. Manganese was analyzed in dust samples, blood, urine and axillary hair by atomic absorption spectro- metry. RESULTS: The average air concentrations of manganese in the three workplace areas were 4 microg/m(3) (range: 1-12 microg/m(3)), 40 microg/m(3) (12-64 microg/m(3)) and 400 microg/m(3) (137-794 microg/m(3)). Manganese in blood and axillary hair correlated with airborne manganese in group-based calculations but not on an individual level. The manganese concentrations varied between 3.2 microg/l and 25.8 microg/l in the blood (mean: 12.2 +/- 4.8 microg/l) and between 0.4 microg/g and 49.6 microg/g in hair (mean: 6.2 +/- 6.2 microg/g in the proximal sequence), respectively. The results for the nonexposed referents were 7.5 +/- 2.7 microg/l (mean) in the blood (range: 2.6-15.1 microg/l) and 2.2 +/- 1.8 microg/g (mean) in axillary hair (range: 0.4-6.2 microg/g). In these matrices, manganese differed significantly between the highly exposed workers and both the reference and the low-exposure group. Manganese in blood revealed the lowest background variance. No differences for manganese in urine were observed between workers (mean: 0.36 +/- 0.42 microg/l, range: 0.1-2.2 microg/l) and referents (mean: 0.46 +/- 0.47 microg/l, range: 0.1-1.7 microg/l). CONCLUSIONS: Manganese in blood is a specific and suitable parameter for the biomonitoring of MnO(2) exposure, although its validity is limited to group-based calculations. Urinary manganese failed to allow a differentiation between exposed workers and referents. The suitability of manganese analysis in hair for biomonitoring purposes suffers from a relatively great background variation as well as from analytical problems.
Adult↗