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Biomedical subjects

G Triebig

Publications and source records attributed to G Triebig.

At least 37 records · Page 2Linked to original sources

Effects of dioxins and furans on liver enzymes, lipid parameters, and thyroid hormones in former thermal metal recycling workers.

A cross-sectional study was performed to examine the internal exposure of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDF) in former workers in a nonferrous metal recycling facility. Liver enzymes, lipid parameters, and thyroid hormones were measured to check possible biologic effects. Compared to background levels, the international toxicity equivalent levels of exposed workers were slightly elevated (median 42 ppt, range 13-281 ppt). The workers also had higher total PCDF concentrations (median 128 ppt, range 30-1138 ppt). Correlation analyses demonstrate significant associations with only one liver enzyme, alanine aminotransferase. There were no such associations with serum cholesterol levels or with serum thyroid hormones. Because of the cross-sectional design of the study, firm conclusions cannot be drawn. For further evaluation, a follow-up examination appears necessary.

Adult↗

Multiple choice vocabulary test MWT as a valid and short test to estimate premorbid intelligence.

The discrepancy between current and premorbid ability is a relevant indicator of acquired mental impairment, which itself is closely related to general cerebral dysfunction. The use of tests sensitive to cerebral dysfunction, raises relatively few problems compared with tests being resistant that are used to estimate premorbid mental ability. For premorbid ability, verbal tests assessing knowledge, especially vocabulary, have been shown to be valid. A test, possibly more insensitive to brain dysfunction than the ones usually administered, is the multiple choice vocabulary test (MWT = Mehrfachwahl-Wortschatz-Test). At present only German versions are available. They are presented in some detail because of their advantages. Construction of the MWT is simple, and it can be easily administered in about five minutes. The results correlate fairly well with global IQ in healthy adults (median of r = 0.72 in 22 samples) and are more insensitive to current disturbances than such tests as the WAIS vocabulary test. The limitations of premorbid tests with respect to diagnostic validity are discussed. It is concluded, that studies which do not control premorbid intelligence have to be considered as a "malpractice" and should not be accepted by scientists.

Adolescent↗

Hepatotoxic effects of solvent exposure around permissible limits and alcohol consumption in printers over a 4-year period.

Two field studies were carried out in 1987 and 1991 in order to evaluate the effect of chronic exposure to solvent mixture on liver enzyme patterns. The results in 33 workers who participated in both studies and had complete sets of data are presented. The magnitude of chemical workload was assessed by means of ambient air monitoring and biomonitoring of solvent concentrations. Alanine aminotransferase, aspartate aminotransferase and gamma-glutamyl transpeptidase were used as markers for possible biological effects. No dose-response relationship was found between exposure to complex solvent mixtures in ambient air, reaching and sometimes even exceeding the threshold limit values for mixtures, and liver enzyme activities. Self-reported alcohol intake was the only factor identified as statistically related to increased liver enzyme activity.

Adult↗

Brain imaging techniques applied to chronically solvent-exposed workers: current results and clinical evaluation.

The application of neuroimaging techniques such as cerebral blood flow (CBF), single photon emission tomography (SPECT), X-ray computed tomography (CAT), and magnetic resonance imaging (MRI) on solvent-exposed workers and patients with toxic encephalopathy results in different and somewhat inconclusive pictures. The aim of this paper is to therefore critically review the current knowledge on chronic neurotoxicity of solvent exposures with respect to neuroimaging technique. CAT measurements of 86 house or construction painters, 82 spray painters, and 81 nonpainters showed no abnormal diffuse brain atrophy due to chronic solvent exposure after controlling for confounding variables such as age, alcohol consumption, or former disease. Correlation analyses did not show any consistent, biologically plausible exposure-effect relationship. Neuropsychologic test results did not correlate significantly with CAT parameters, whereas a strong age dependency exists. It is concluded that long-term exposure to solvent concentrations not exceeding permissible occupational limit values does not cause increased brain atrophy.

Brain↗

Neurotoxicity of solvent mixtures in spray painters. I. Study design, workplace exposure, and questionnaire.

A multidisciplinary cross-sectional study was carried out in 105 spray painters with long-term solvent exposure (10-44 years) and in 58 control subjects not exposed to solvents. By means of air monitoring the solvent concentrations in the ambient air during spray painting were determined using charcoal and silicagel tubes with pumps and passive samplers. In general, the air concentrations of the individual compounds did not exceed the current limit values (MAK values). Aromatic hydrocarbons like toluene, xylene, ethylbenzene, trimethylbenzene, aliphatic hydrocarbons (e.g., heptane) and acetates (ethylacetate, butylacetate) were determined to be important components of paint solvents. However, in unfavorable work conditions the "exposure index" could exceed the permissible limits two or three times. To assess the body solvent load at the time of examination, biological monitoring (BM) was performed. The main finding was that there was no evidence of neurotoxicologically relevant solvent exposure. Only in the case of methyl hippuric acid in urine spot samples did the spray painters show a higher mean value (80 mg/l) than control subjects (below 20 mg/l), indicating recent xylene exposure. Elevated urinary chromium concentrations (maximum value 29 micrograms/l) were found in 28 spray painters as a result of using zinc chromate-containing wash primers without taking protective measures. To assess the degree of past solvent exposure a special questionnaire was used. This included variables like duration and amount of solvent exposure, the presence of a technical ventilation system, health complaints during painting, etc. Additionally, three "solvent exposure indices'' (SEI) were calculated and used for evaluation of "dose-effect relationships.''(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Neurotoxicity of solvent mixtures in spray painters. II. Neurologic, psychiatric, psychological, and neuroradiologic findings.

A multidisciplinary cross-sectional study was performed to examine the chronic neurotoxicity of organic solvents. Participating in the study were 105 persons employed as spray painters and having long-term solvent exposure (10-44 years) and a control group consisting of 58 construction workers, electricians, and plumbers without occupational contact to solvents. Samples were matched for age, preexposure intelligence level, occupation, and socioeconomic status. After controlling for potentially non occupational confounding factors (neuropsychiatric diseases, metabolic disorders, high blood pressure, alcohol intake) 83 spray painters and 42 controls were entered finally into the study. The evaluation included work history, self-rating questionnaire, neurologic investigation, psychiatric analysis using the Present State Examination (PSE), psychological testing, and computerized axial tomography (CAT) of the brain. Physical and neurologic examinations demonstrated no case of overt disorders of the central or peripheral nervous system. An important result of the psychiatric analysis was that the syndromes "special features of depression" and "loss of interest and concentration" occurred significantly more frequently among spray painters than among controls. Further analyses demonstrated an association with chronic exposure over 30 years and repeated acute neurotoxic effects during solvent exposures. Neither psychological nor performance tests demonstrated any statistically significant differences in the performance sets after adjustment according to premorbid intelligence level; this finding supports the presumption of only a low grade of mental dysfunction. Correlation analyses indicated a relationship between subjective health complaints and long-term solvent exposure; however, the effect of age cannot be completely ruled out.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

[Pilot study of the prevalence of a hyperreactive bronchial system in various occupationally-induced lung diseases].

A pilot study was performed to assess the prevalence of hyperreactive bronchial system (HBS) in various occupational lung diseases. 204 patient records were evaluated with the following diagnosis: Allergic rhinitis: (N = 25, 12%), allergic bronchial asthma (N = 70, 34%), toxic asthma (N = 22, 11%), silicosis (N = 12, 6%), asbestosis (N = 15, 7%), farmer's lung (N = 12, 6%), chronic unspecific respiratory syndrome (N = 48, 24%). In each case an inhalative methacholine test (MCHT) was performed. HBS was considered to be present whenever there was a resistance increase of more than 100% of the baseline values. The prevalence of HBS varied between 50% (asbestosis) and 77% (toxic asthma); the average was 68%. Allergic diseases showed a higher prevalence of 71% in comparison to nonallergic diseases with 65%. Patients with silicosis or asbestosis and without additional chronic bronchitis or emphysema demonstrate a "normal" prevalence of HBS of 11%. Age, gender, smoking, alcohol, family history of allergy and repeated bronchitis, the number of eosinophils in the blood. IgE concentration in serum showed no significant association with an increased prevalence of HBS. The coincidence of anamnestically affirmed or denied bronchial hypersensitivity to environmental factors, and the positive or negative result of the MCHT test, was relatively low, being only 43% in case of a "positive" test and 17% in case of a "negative" test.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

Formaldehyde exposure at various workplaces.

The results of formaldehyde determinations in the air at various workplaces in the period 1980-1988 are presented. The airborne concentrations varied between less than 0.01 and 10.9 mg m-3 (mean 0.7 mg m-3). For ambient air monitoring, active sampling and capillary gas chromatography are reliable and sensitive methods. Formic acid excretion in urine is an unspecific and insensitive biological indicator for monitoring low-dose formaldehyde exposure.

Air Pollutants, Occupational↗

Clinical and neurobehavioural study of the acute and chronic neurotoxicity of styrene.

A cross sectional field study of workers exposed to styrene was performed to evaluate possible acute and chronic neurotoxic effects. A total of 36 workers of four companies handling polyester resin materials for one to 16 years (median: 7 years) and two control groups were each examined on a Monday. The control group 1 (formed to compare acute effects) consisted of 20 men from two companies with no exposure to neurotoxic chemicals. To compare chronic effects, a second control group was formed by "one to one matching" with respect to age, socioeconomic status, and pre-exposure intelligence level. Ambient air monitoring using active sampling (short time) and passive samplers (long time) showed styrene in air concentrations as follows: range 3-251 ppm (median: 18 ppm) and concentrations 140-600 ppm during lamination of the inside of boats. For biological monitoring the results were as follows (postshift samples: range/median): styrene in blood: 5-482 micrograms/dl (39 micrograms/dl), mandelic acid urine: 0.01-3.64 g/l (0.21 g/l), and phenylglyoxylic acid urine: 0.01-0.87 g/l (0.19 g/l). The clinical examination found no signs or symptoms of peripheral neuropathy or encephalopathy. The principal work related health complaints were acute, reversible irritation of the eyes that occurred after exposure to styrene concentrations of 200 ppm or more. The neurobehavioural tests showed no significant differences in acute effects (p greater than 0.05) between the two groups or between preshift and postshift testing. Nor were there any significant differences in the relevant neurobehavioural variables between the styrene workers and the controls. It is concluded that occupational exposure to styrene concentrations in air up to 100 ppm causes no adverse acute or chronic effects on the central nervous system.

Acute Disease↗

[Formaldehyde determination in tobacco smoke--studies under experimental and actual conditions].

The estimation of an external exposure to formaldehyde in tobacco smoke requires a reliable analytical method. The gas chromatographic determination of formaldehyde shows in comparison to photometric methods a higher sensitivity and specificity. In the main stream smoke of various kinds of cigarettes the amount of formaldehyde vary between 3.4 micrograms to 8.8 micrograms/cigarette, this is equal to concentration between 2.3 to 6.1 ppm. In the air of lounges in hospitals formaldehyde concentrations up to 0.19 ppm can be detected after smoking of 15 cigarettes over a period of 1.5 h. In kindergartens without tobacco smoke the formaldehyde concentrations in air range from 0.005 to 0.01 ppm. The smoking of 30 cigarettes and one pipe in a non ventilated room over 1.5 h exceeded formaldehyde concentrations between 0.21 to 0.45 ppm. The concentration declines to 0.08 ppm within 2h after termination of smoking. The MAK-value of 0.5 ppm is not exceeded; in contrast to this the indoor limit of 0.1 ppm recommended by the German Bundesgesundheitsamt is exceeded in the vicinity of the smoker. The formaldehyde concentrations in tobacco smoke reported in the older literature can not be confirmed; this is due to the nonspecificity of the photometric methods. On the basis of our results can be concluded that the irritating effects of tobacco smoke to the mucous membranes are the result of the sum of irritating effects caused by several compounds and particles in the smoke and not only the impact of formaldehyde.

Air Pollutants↗

Cross-sectional epidemiological study on neurotoxicity of solvents in paints and lacquers.

In a multi-disciplinary retrospective study we examined 105 house painters employed for at least ten years (median 27 years, range 10-36 years). Fifty-three workers from various professions (non-painters), who were matched with regard to age, occupational training and socio-economic status served as the control group. In both groups no cases of a clinically manifest polyneuropathy or encephalopathy were found. The neurophysiological examinations (EEG and NCV-measurement) showed no differences in painters and controls that would indicate adverse effects of organic solvents. There were no cases with neuroradiological findings of a diffuse cerebral atrophy. Furthermore the evaluation of certain brain structures (ventricular diameter, cella media index) of the CAT films did not reveal any significant differences. In the neurobehavioral tests significant differences in the results were only found in the subtests "change of personality" and "short term memory capacity" in a subgroup of painters with repeated prenarcotic symptoms at the workplace. Ambient air monitoring measurements at 30 representative workplaces showed that the concentrations of the main components of the solvent-mixtures were well below the MAK-values. The results of the "Erlangen Painter Study" does not confirm former epidemiologic findings from other countries, mainly Denmark. However, there are some aspects, such as minor solvent exposure in German house painters, insufficient diagnostic and etiological procedures as well as misclassifications which may explain the different experiences.

Adolescent↗

Pentachlorophenol and the peripheral nervous system: a longitudinal study in exposed workers.

A longitudinal study was performed to examine whether chronic occupational exposure to pentachlorophenol (PCP) or its compounds causes measurable alterations in the conduction velocity in peripheral nerves as an "adverse effect." In total, the results of nerve conduction velocity (NCV) determinations in 1980 and 1984 in 10 subjects (7 men, 3 women) who had been exposed for an average of 16 years (range 4-24) were available. The concentrations of PCP in the air at the workplace varied between 0.3 and 180 micrograms/m3 and were thus below the maximum allowed concentration (MAK value) of 500 micrograms/m3. The biological monitoring carried out showed the following results: PCP in the serum: 38-1270 micrograms/l; PCP in the urine: 8-1224 micrograms/l. Compared with the upper normal limits (PCP in the serum 150 micrograms/l, PCP in the urine 60 micrograms/l), distinct internal exposure to PCP has resulted in some of the employees. Determinations of the NCV of motor and sensory nerve fibres (ulnar, median, peroneal, and sural nerve) were always in the normal range. A significant difference in the NCV for the period 1980-4 could not be detected. In addition, the correlation analyses did not show any hints of "dose-effect relations." It is concluded that occupational exposure to PCP over several years in the concentrations observed probably do not lead to any adverse effects on the peripheral nervous system.

Adult↗