Biomedical subjects
Publications and source records attributed to G Triebig.
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We examined eighteen workers (three women, 15 men) in a pentachlorophenol (PCP) processing factory, with a mean activity of 12 years. PCP in blood and urine samples was analyzed by gas chromatography. To evaluate the peripheral nervous system the maximal motor as well as sensory nerve conduction velocities of the ulnar and/or median nerve were measured. The PCP-levels in plasma ranged between 0.02 and 1.5 ng/l, median 0.25 ng/l, and in urine between 13 and 1,224 micrograms/l, median 112 micrograms/l, or between 11 and 2,111 micrograms/g creatinine, median 111 micrograms/g creatinine. The median values of the neurophysiological parameters showed a mild degree of slowing in the PCP-collective. In the case of the sensory nerve conduction velocities, this decrease was significant. A dose-effect relationship between internal PCP-load and the different nerve conduction velocities could not be demonstrated. The individual evaluation of the toxicological and neurophysiological results gave hints that in some cases decreased nerve conduction velocity is caused by chronic exposure to PCP.
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Halogenated hydrocarbons with over 150 toxicological relevant substances represent a considerable group among the numerous noxes at the working-places. Tri- and perchloroethylene are industrially widely used solvents for cleaning, degreasing and extraction. At the workplace the main amount of intake occurs via lung. Hepato-, nephro-, neuro- and cardiotoxicological effects are important solvent-induced health impairments. If the valid maximum concentrations in the work area (MAK-value) for the specific substance is not exceeded, altogether health hazards are impropable. With information of the "Unfallverhütungsbericht" only 23 cases of intoxications at the workplace were indemnified in 1977 for the first time. The causes for this low number are: installation of closed equipments, automation of the procedures and improvement of the personal hygiene. However praxis in occupational medicine shows, that there is a great number of persons in small firms that has contact with these solvents. For the surveillance and judgement of these solvent-exposed persons exist two methods. First the airborne concentration of the chemical compound can be determined at the working area. Second the solvent and/or its metabolites can be quantitative analyzed in the biological material. This method, called "biological Monitoring (BM)" has important advantages. BM should be prefered in cases of non-continuous, short-term exposures to concentrations of high degree. The judgement has to be done in relation to biological permissible limits (Biologische Arbeitsstoff-Toleranz-Werte, BAT, biological threshold limit values, BTLV's). Based on our longtime experience this specific and sensitive method should be used with priority.
A simple, reliable and efficient enzymatic assay for the analysis of formic acid in urine is described. The principle of the method is the quantitative oxidation of the acid with the enzyme formate dehydrogenase (FDH) in the presence of NAD. The detection limit was 0.5 mg/l, the recovery rates ranged from 66% to 74% and the coefficient of variation was 5%. The results obtained with this method correlated well with the values measured with two different gas chromatographic procedures. Normal formic acid excretion in urine is between 2.0 and 30.0 mg/l, with a mean of 13.0 +/- 7.4 mg/l and between 1.2 and 17.5 mg/g creatinine, the mean being 7.7 +/- 4.0 mg/g creatinine. The determination of formic acid concentration in urine may be an important means to quantify the degree of exposure to or intoxication of persons with methanol, formaldehyde and acetone.
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Seven clinical healthy volunteers were exposed to trichloroethylene concentration in air with 520 mg/m3 (100 ppm) at an average 6 hours a day on 5 consecutive days. Corresponding volunteers were exposed to a placebo for the same period. --The persons were examined psychopathometrically and biochemically at the beginning and after every day of exposure. The trichloroethylene-metabolites in blood and urine were dated in order to quantify the loads. --Purpose of the psychopathometrical testing methods was the observation, whether a psychological impairment in the sense of a "psychoorganic syndrome" may occur under these exposition-conditions. --Standardized achievement-tests and self-report rating scales were used in order to demonstrate reversible physical provable psychosis that may be possible. Comparing the psychopathometrical results of the exposed and non-exposed volunteers no statistical significant difference was visible in spite of the analytically proved considerable incorporation of the solvent.
Seven healthy volunteers were exposed to approximately 100 ppm (=520 mg/m3) trichloroethylene for six hours daily during a period of five consecutive days. A corresponding group was exposed a placebo in the same manner. -Biochemical and psychological examinations were accomplished in the beginning and the end of each day respectively the whole period. Thereby the intraindividual as well as the interindividual loads were taken to judge the health impairment. - For this purpose trichloroethylene, trichloroethanol and trichloracetic acid were determined in blood, as well as total trichloroethanol and trichloroacetic acid in urine. For the measurement of the biochemical parameters gaschromatography is considered the best method. The combination of the "intern standard" with the synchronous determination of the metabolites of trichloroethylene is described as a new treatment. These time-efficient and practicable procedures are the most important suppositions for "biological monitoring". Results are confirmed as far as known in literature as well as the course of trichloroethylene in blood is described for the first time. The modern methods of psychology applied to tests and standardized questionaires served to quantify the intellectual and psychological conditions of the solvent exposed volunteers and of their corresponding group. The group results were compared. Thereby no significative differences were visible. Altogother the results show that during the 5 days exposition to 100 ppm (=520 mg/m3) trichloroethylene no impairments of the examined persons' mental and psychological capacities could be determined in spite of the biochemically quantified incorporation of the solvent.
The results of two field studies in painters and spray painters, the outcomes of examinations of workers with suspected work-related disease due to solvents, as well as data from an evaluation of an epidemiologic study in painters with confirmed occupational disease, are presented and discussed. The results of these studies and the experiences in occupational medicine in the Federal Republic of Germany do not support the assumption of high neurotoxic risks in solvent-exposed workers, which can be postulated from various epidemiologic studies from Scandinavian countries. Several factors may explain the different conclusions: 1) lower solvent exposures of German painters in the past decades; 2) false positive diagnosis of a toxic encephalopathy; 3) aetiological misclassification; 4) differences in legislation relevant for the acknowledgement of occupational diseases. In conclusion, there is a need for further well-designed epidemiologic studies in occupationally solvent-exposed workers. Suggestions regarding assessment of exposure and neurobehavioral tests are given.
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Mercury levels in blood and urine and several nerve conduction velocities (CV) were measured in two groups of workers exposed to mercury (Hg) and in a reference group. Furthermore neuropsychiatric examination and psychological tests were performed. There was a significant mild degree of slowing of sensory CV, but no dose-effect relationship was evaluated on a group basis. The individual assessment showed in some cases hints of abnormal CV caused by mercury exposure. Significant correlations were found between duration of exposure and decrease of short-term memory. However there was no relationship in the case of the other psychological tests. In conclusion, results indicate that there are no disorders of central and/or peripheral nervous system function if the valid Biological Threshold Limit Values in FRG (50 micrograms Hg/l blood and/or 200 micrograms Hg/l urine) are not exceeded.