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Biomedical subjects

E Kiesswetter

Publications and source records attributed to E Kiesswetter.

At least 19 recordsLinked to original sources
PubMed2003

Longitudinal study examining the neurotoxicity of occupational exposure to aluminium-containing welding fumes.

OBJECTIVES: The neurotoxicity of occupational exposure to aluminium (Al)-containing welding fumes has been discussed with controversial results. The aim of the longitudinal study was to examine a group of Al welders for significant central nervous changes in comparison with a non-exposed cohort. METHODS: A group of 98 Al welders (mean age 37 years) in the car-body construction industry, with a median of 6 years of occupational exposure to Al welding fumes, and an education-matched, gender-matched, age-matched control group of 50 car-production workers (mean age 36 years) at the same plant, were included in this longitudinal study. Two cross-sectional studies were done in 1999 and 2001. In the second cross-sectional study 97 welders and 50 controls could be examined. The examination programme consisted, for example, of a standardised anamnesis, focussing on occupational history, education, illnesses, medication, accidents and current alcohol consumption, a physical examination that included neurological status, and the assessment of Al concentration in plasma and urine. The neurobehavioral methods included a symptom questionnaire, modified Q16, and computerised and non-computerised tests: psychomotor performance (steadiness, line tracing, aiming, tapping), verbal intelligence (WST), simple reaction time, digit span, block design (HAWIE), symbol-digit substitution, digit span, switching attention (European neurobehavioral evaluation system, EURO-NES), and standard progressive matrices. The data were analysed by multivariate analysis of covariance (MANCOVA) for repeated measurements with covariates age, education, and carbohydrate-deficient transferrin in plasma (CDT). RESULTS. The median Al urine concentration (mean preshift/postshift) was 52.4 microg/g creatinine (2001) and 57.6 microg/g creatinine (1999). Median respirable air dust was 0.67 mg/m(3) (2001) and 0.47 mg/m(3) (1999). Welders and controls did not report significantly more symptoms in the modified Q16. Furthermore, no significant differences in psychomotor performance and other neurobehavioral tasks, except for reaction time, were seen between welders and non-welders. Regression analyses reveal a significant relationship between reaction time and Al excretion in urine that was confounded by other factors. CONCLUSIONS: At present the outcome for reaction time has to be interpreted as a single result. However, as the modified Q16 questionnaire and the rest of the psychomotor performance showed no significant changes, the next cross-sectional study, in 2003, will provide further information on which a final conclusion can be based.

Adult↗
PubMed2003

Physiological and psychological approaches to chemosensory effects of solvents.

Workplace related standard settings for solvents are based in a remarkable extent on information about sensory irritations. However, data from controlled human exposure studies are seldom available. Therefore, the aim of this study was to present the association of self-reported symptoms and physiological processes leading to sensory irritations. Three series of laboratory experiments each with 24 young male subjects were performed. Ethyl benzene (EB), 2-butanone (methyl ethyl ketone or MEK), isopropyl alcohol (IPA), 1-octanol (OCT), and 2-ethylhexanol (EHEX) were investigated in low and high concentrations. Ratings for sensory irritations (eyes and nose), olfactory symptoms, and annoyance were assessed repeatedly before, during and after the 4-h-exposures. The anterior active rhinomanometry (AAR) was employed measuring the nasal flow. The nasal lavage was used for the analysis of the neuropeptide substance P as indicator of nasal chemosensory irritations. Goodness-of-fit was calculated for non-linear regression analyses by fitting the sine function on the data of the ratings given during the 4-h-exposure. In general, ratings for annoyance and odor symptoms were fitted on a higher level than those for sensory irritations. However, a high fit could be shown for nasal irritations due to EHEX. In these experiments, a significant reduction of the nasal flow and a significant increase of substance P could be proved.

Administration, Inhalation↗
PubMed2000

Subjective symptoms due to solvent mixtures, dioxin, and toluene: impact of exposure versus personality factors.

In this study, we analyse the impact of personality factors on the frequency of self-reported symptoms for workers under different exposure conditions. Reported symptoms may depend on the level and type of exposure, as well as on personality factors such as trait anxiety of the worker or his general sensitivity with regard to the environment. The employed data stems from three studies: The first study contains information of 60 workers who suspected to be exposed to polychlorined dibenzodioxins and dibenzofuranes (Lifetime Weighted Average Exposure, LWAE, as an index for contact with the substances). The second study concerns 40 workers who are exposed to different concentrations of solvent mixtures in paint manufacturing (LWAE of total hydrocarbons about 10 ppm). The third study includes repeated measurements of two subgroups of workers from rotogravure printing plants who are exposed to different concentrations of toluene: a "high" exposure group (n = 129, LWAE about 46 ppm, current exposure 25 ppm) and a "low" exposure group (n = 96, LWAE for toluene about 9 ppm, current exposure 3 ppm). Trait anxiety, environmental sensitivity, and self-reported symptoms are measured by validated questionnaires and age as well as verbal intelligence are controlled. To determine the effect of the individual characteristics and the different exposures on self-reported symptoms, frequency analyses and variance analyses are conducted and linear models are fitted. For all analyses, trait anxiety explains the highest share of the variance. If there is no effect of the exposure on the reported symptoms (dioxin and low-level toluene study), trait anxiety seems to have a larger explanatory power in comparison with those studies where the exposure has an effect on the reported symptoms (solvent-mixture and high-level toluene study). Neurotoxicological risk analysis has to account for the detected dependence of self-reported symptoms on personality traits: assessments for elevated symptoms should not only be linked to the intensity of exposure but also related to benchmarks derived from the normal variability of personality factors.

Adaptation, Psychological↗
PubMed2000

Neurobehavioral study on the interactive effects of age and solvent exposure.

Initial research revealed interaction effects on health measures between exposure to neurotoxicants and age. Symptom reports of workers were conspicuously increased if high-concentration occupational exposure (e.g. to organic solvents, lead) was combined with age above 54 years. The symptom increase in elderly workers was interpreted as a possible indicator of a biological vulnerable phase or delayed response of former high exposure. A second study of the hypothesized age-exposure interaction was performed with a group of workers who had homogenous exposure to a single organic solvent using a neurobehavioral performance evaluation (the EURO-NES). Workers in the rotogravure printing industry who were exposed to toluene were examined two times with an interval of one year (n =333/278). The sample was stratified by workers with significantly different toluene exposure, printers and end-processing operators, and four age classes (< 31, 31-40, 41-50, > 50). The mean lifetime weighted average exposure (LWAE) varied depending on age classes and years of employment with exposure between 7 and 17 ppm in the operators and between 35 to 62 ppm toluene in the printers. Multivariate analyses revealed a significant performance decrease with age (simple reaction time, symbol digit, switching attention, digit span). Again an interaction between age and exposure was found depending on diverging psychometric performance trends with older age. However, contrary to the hypothesis the group with higher exposures (printers) and older age revealed better performance and less symptoms than the group with lower exposure (end-processing operators). The paradoxical results are explained by differences in the intellectual capability in the oldest strata and a possible reversibility of neurobehavioral effects of former high toluene exposure under the condition of later low exposure. There are no hints of adverse delayed effects of former toluene exposure in a possible vulnerable phase in age over 50 years. The different interaction findings of the initial and present study seem to depend mainly on exposure differences in quality and quantity.

Adult↗
PubMed1999

'Multiple chemical sensitivity', the relevance of toxic, neurobiological and psychic effect mechanisms.

The review deals mainly with the key question of chemical causation of multiple chemical sensitivity (MCS). There are only few human studies with valid information on chemical exposure and in no study the chemical toxic causation hypothesis is supported. The animal model of olfactory-limbic/neural sensitization is of heuristic value to explain MCS phenomena and includes both chemical and non-chemical stressors. However, in animal studies seldom chemical substances and exposure levels were used which might be of relevance in the formation of MCS. The problem is demonstrated for toluene exposures in human and animal sensitization studies. In accordance with the sensitization hypotheses, human studies prove a generalized vulnerability to environmental stimuli in subjects with self-reported MCS. However, study designs do not allow to deduce whether the strong responsivity is a premorbid or comorbid phenomenon or is related to exposure. Alternative study approaches to evaluate dose-response relationships are proposed.

Animals↗
PubMed1998

Effects of sleep loss, time of day, and extended mental work on implicit and explicit learning of sequences.

Tacit knowledge is part of many professional skills and can be studied experimentally with implicit-learning paradigms. The authors explored the effects of 2 different stressors, loss of sleep and mental fatigue, on implicit learning in a serial-response time (RT) task. In the 1st experiment, 1 night of sleep deprivation was shown to impair implicit but not explicit sequence learning. In the 2nd experiment, no impairment of both types of sequence learning was found after 1.5 hr of mental work. Serial-RT performance, in contrast, suffered from both stressors. These findings suggest that sleep deprivation induces specific risks for automatic, skill-based behavior that are not present in consciously controlled performance.

Adolescent↗
PubMed1997

Solvent exposure and ratings of well-being: dose-effect relationships and consistency of data.

Ratings on analog scales for dimensions of well-being provide information about the acute state of well-being during solvent exposure. In a study of volunteers and workers exposed to solvents, tension, tiredness, complaints, and annoyance were rated on seven-point scales. Dose-effect relationships were analyzed for several scenarios; data were collected in diaries during work hours. In two studies, 40 volunteers in an exposure laboratory were exposed to ethanol by inhalation at levels between 80 and 1900 parts per million (ppm). In two other studies, 32 volunteers were exposed to acetone and ethyl acetate in single exposures (1000 and 500 ppm, respectively) and combined exposures (500 ppm acetone + 200 ppm ethyl acetate). A field study of 8 exposed workers and 8 nonexposed controls involved exposures of up to 2100 ppm acetone. Dose-effect relationships were shown for ratings of annoyance by correlations of 0.36 (ethanol) and 0.58 (acetone). Similar coefficients were found for ratings of complaints. The dimensions tension and tiredness showed no stable relationship with exposure. The consistency of ratings was assessed by means of correlations between the ratings given during periods of nearly equal exposures. Ratings of annoyance for the different studies between the periods of nearly equal exposure showed average correlations from 0.68 to 0.84. For the ratings of complaints, the coefficients were 0.53 to 0.81. The coefficients for tension had similar stabilities; those for tiredness were lower.

Acetates↗
PubMed1997

Standardization of a questionnaire for neurotoxic symptoms.

A new version of the "Psychological-Neurological Questionnaire," designed for screening purposes, was investigated concerning its sensitivity to detect early signs of occupational exposure to potential neurotoxicants. A study population of 361 subjects was stratified into four age groups (<34, 35-44, 45-54, and >54 years) and three exposure groups (no, low, and high). According to dose and exposure history, workers exposed to dioxins and furans in combustion products, to volatile organic compounds, and to chromates were classified as low exposure. Workers exposed to alkyl lead, single solvents, and solvent mixtures were classified as high exposure. Only the group with the oldest age and highest exposure could be separated clearly from other groups, indicating an interaction effect between exposure and age. The low-exposure group could not be separated from the nonexposed controls. The most effective discriminators were neurologic symptoms. Psycho- and neurovegetative lability and irritative disturbances contributed less to the differentiation. Gastrointestinal and sleep disorders, as well as alcohol intolerance, showed no differentiation quality. The observed type of interaction effect fits models of delayed neurotoxicity.

Adult↗
PubMed1997

Solvent Exposure, Shiftwork, and Sleep.

The effects of different conditions of occupational exposure to organic solvents on subjective sleep quality were studied with and without shiftwork. Laboratory studies showed that four hours of daytime exposure to ethanol (400, 800 ppm) by inhalation led to blood ethanol levels below 0.01 per thousand and had marginal effects on the following night's sleep. Exposures to acetone (1,000 ppm), ethyl acetate (400 ppm), and a solvent mixture (acetone 500 ppm, ethyl acetate 200 ppm) increased the subjective depth of sleep. In a field study with eight hours of exposure, during three different work shifts, dose-response relationships between acetone concentrations during the shiftwork and the depth of sleep were found. Nevertheless, the solvent-exposed shift workers reported a reduced sleep quality, mainly in connection with daytime sleep, in comparison with non-exposed shift workers. The effects of solvent exposure during shiftwork on sleep varied with time of day of the exposure.

Journal Article↗
PubMed1994

Acute exposure to acetone in a factory and ratings of well-being.

Eight workers occupationally exposed to acetone and eight nonexposed controls were investigated on nine shift days both during work and leisure. The mean exposure to acetone was near 1000 ppm (2400 mg/m3). Acetone in urine was moderately correlated to acetone in the air. Ratings on scales of well-being and acute symptoms (SPES) correlated significantly with concentrations of acetone in urine but not with concentrations of acetone in the air.

Acetone↗
PubMed1992

Correlations between subjective disturbances due to acute exposure to organic solvents and internal dose.

A general tendency to minor subjective disturbances ("susceptibility") were measured by questionnaire scores of psycho-/neurovegetative lability in 32 subjects independent of any experience with solvents. In series of experiments interrelations between subjective and biological variables during experimental exposures for 4 or 8 hr to acetone (1000 ppm), ethyl acetate (400 ppm), acetone/ethyl acetate mixture (500/200 ppm), or filtered air were investigated. Every two hr ratings of "tension", "tiredness", "complaints" and "annoyance" were reported and samples of urine were collected in order to analyse the internal dose of the substances. In exposures to ethyl acetate and to the mixture, the mean levels of urinary excretions of the substances show significant cross-correlations to rated complaints and annoyance, but not to rated tension and tiredness. Those subjects who showed higher susceptibility reported higher ratings of complaints and annoyance in those exposure conditions containing ethyl acetate. In exposures to acetone these relations were not found. Both, the quality of the substances and the individual tendency to report slight health impairments influence the variability of subjective reactions on exposure to solvents.

Acetates↗
PubMed1989

[Effect of performance and state orientation on achievement and attention indicators in a simple stimulus-response task with and without performance feedback].

In formulating his theory of action control, Kuhl (1983) proposed two motivational states: action orientation and state orientation. People who are action oriented are able to ignore all informations in concrete situations which are irrelevant with regard to the preferred goals. Persons who are state oriented tend to focus sooner on the outlast aspects of a special state. Kuhl introduced a questionnaire HAKEMP to record these tendencies. Further on, there occurs the general assumption that in a particular state of state orientation, people have only a limited processing capacity for given tasks. This hypothesis was tested in an experiment (n = 88) with a stimulus-reaction task. The conditions were varied by the type of the task (fixed or variable stimulus interval) and feedback for the subjects' ability to react. It was expected that for the fixed stimulus interval condition, state-oriented people would be less efficient than action-oriented subjects; with feedback there should be increasing results. The experiment however, shows no significant difference between the performance of state- and action-oriented subjects. These results are discussed in relation to modifications of the HAKEMP questionnaire.

Adolescent↗
PubMed1986

Algorithms for the computerised construction of shift systems which meet ergonomic criteria.

A search algorithm is presented to generate all shift systems according to a given set of constraints, including physiological and social requirements. The generated shift systems are weighted according to such criteria as the time distribution of the shifts, the length of the weekend leisure time and the regularity of the shift system. The use of this algorithm is restricted to the construction of shift systems for a maximum of five crews, as is usual in industry. A heuristic algorithm for the construction of more complex shift systems, as used in the services sector, is also described. The user of the program may consider all criteria simultaneously. He must assign priorities to the criteria according to his wishes.

Journal Article↗
PubMed1984

[Effect and adverse effects of epidural anesthesia during labor. With special reference to changes in the cardiotocogram].

In an Obstetric Department with approximately 2,000 deliveries yearly, offry third mother is delivered under epidural anesthesia. In a group of 600 maternity patients, the effectiveness, the side effects and the changes in the fetal cardiotocogram were examined during labour and delivery under epidural anesthesia. Evaluated were questionnaire to the mothers with mainly subjective impressions, the anesthetic protocol, and the protocol of labour and delivery including the internal cardiotocogram. 85% of the mothers would have a future delivery under an epidural anesthesia. The incidence of headaches and its independence of the type of obstetric analgesia and anesthesia is mentioned. The number of punctures, the technique of epidural anesthesia, the concentration of the local anesthetic used, failures and side effects are described. The incidence of cesarian sections, fetal morbidity and changes in the cardiotocogram are discussed in detail. The incidence of transilent silent decelerations and alarm dips in the cardiotocogram are mentioned. This study shows that epidural anesthesia is free of risks and a highly effective method for the conduct of obstetric analgesia.

Anesthesia, Epidural↗
PubMed1983

Time-budget studies of policemen in weekly or swiftly rotating shift systems.

For 8 days 120 policemen kept special diaries including working time, travelling to and from work, leisure time and sleeping time. By analysing the data of leisure and sleep in relation to the time of day and the type of shift it is possible to find out critical points within a shift system. The mean duration of sleep was reduced before morning shifts, between night shifts and after a morning shift that was followed by a night shift on the same day. The leisure time was limited in connection with afternoon shifts and between the combined morning and night shift. It is recommended not to have double shifts on one day. Rapidly rotated shift systems had more advantages referring to the total amount of night sleep than weekly rotated shift systems. The backward rotation of shifts was unfavourable because of the short time off between the last afternoon shift and the first morning shift. Furthermore, short nightwork periods and a start of the morning shift which is not too early seem to be preferable.

Journal Article↗
PubMedDate not supplied

Neurobehavioral effects of a long-term exposure to tetraalkyllead.

Employees of a factory producing antiknock additives for gasoline were examined psychologically after an exposure of an average of 14 years. A neurobehavioral symptom questionnaire, tests of single and choice reaction time, a cancellation task and a digit symbol test were the neurobehavioral variables. Total lead in urine and trimethyllead in urine showed different patterns of correlation with the neurobehavioral measures. Intellectual abilities (logical reasoning), age, and job years were controlled by partial correlation statistics as possible confounders. Referring to the low level of 21 micrograms lead per 100 ml blood and regarding the dose-response relations reported in the literature, the results support the hypothesis of a special neurotoxicity of the alkyllead compounds.

Adult↗