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Biomedical subjects

A Aitio

Publications and source records attributed to A Aitio.

At least 19 recordsLinked to original sources
PubMed1998

Exposure of gasoline road-tanker drivers to methyl tert-butyl ether and methyl tert-amyl ether.

Organic oxygenates, namely, methyl tert-butyl ether (MTBE) and methyl tert-amyl ether (MTAE), are added to gasoline to reduce carbon monoxide in exhausts and to enhance the octane number. The aim of this study was to investigate road-tanker drivers' exposure to oxygenate vapors during road-tanker loading and unloading as well as to evaluate the measurements of these ethers and their metabolites in the urine as a means of assessing the uptake of the ethers. A total of 11 drivers in different parts of Finland were trained to monitor their exposure with personal samplers, to report their working conditions, and to collect their whole-day urine samples. Charcoal tubes of the air samples were analyzed for MTBE, MTAE, benzene, toluene, and aliphatic hydrocarbons. For biological monitoring purposes the two main oxygenates, tertiary ethers MTBE and MTAE, as well as their main metabolites, tertiary alcohols tert-butanol (TBA) and tert-amyl alcohol (TAA), were determined in urine specimens. On average the drivers were exposed to vapors for short periods (21 +/- 14 min) three times during a work shift. The mean concentrations of MTBE and MTAE (mean +/- SD) were 8.1 +/- 8.4 and 0.3 +/- 0.4 mg/m3. The total MTBE uptake during the shift was calculated to be an average of 106 +/- 65 mumol. The mean concentrations of MTBE, TBA, MTAE and TAA detected in the first urine after the work shift were 113 +/- 76, 461 +/- 337, 16 +/- 21, and 40 +/- 38 nmol/l, and those found the next morning, 16 h later, were 18 +/- 12, 322 +/- 213, 9 +/- 10, and 20 +/- 27 nmol/l. The good relationship (r = 0.84) found between MTBE exposure and postshift excretion suggests that urinary MTBE can be used for biological monitoring of exposure, but at the present low level of exposure the corresponding metabolite TBA is not equally reliable. The determination of MTAE and its metabolite TAA in urine is sensitive enough to detect the low degree of exposure to MTAE, but in this study the data were too scarce to allow calculation of the correlations due to very low levels of MTAE exposure.

Adult↗
PubMed1997

Biological monitoring of exposure to benzene in the production of benzene and in a cokery.

The purpose of this study was to compare different biological methods in current use to assess benzene exposure. The methods involved in the study were: benzene in blood, urine and exhaled air, and the urinary metabolites t,t-muconic acid (MA) and S-phenylmercapturic acid (S-PMA). Blood, urine and exhaled air samples were collected from workers in a benzene plant (pure benzene exposure) and cokery (mixed exposure, e.g. polycyclic aromatic hydrocarbons--PAHs) in an Estonian shale oil petrochemical plant. The benzene in these samples was analysed with a head-space gas chromatograph, and the metabolites MA and S-PMA with a liquid chromatograph using methods developed from published procedures. Some of the values measured in the Estonian shale oil area were high in comparison with those published during the last few years, whereas the values measured in the control group did not show any exposure to benzene except in the smokers group. The highest median exposure was in the benzene factory, 0.9 cm3/m3 TWA (2.9 mg/m3) and the highest individual value was 15 cm3/m3 TWA (49 mg/m3). All biological measurements in this study gave the same assessment about exposure to benzene and correlated highly significantly with each other and with the air measurements (r = 0.8 or more). In the benzene factory the correlation was good even when calculated from samples with air concentration < 1 cm3/m3 (3.2 mg/m3) in the case of blood benzene and urinary MA. However, for S-PMA it was weak (r = 0.4) and for benzene in urine and exhaled air it did not exist any more. In the cokery, with mixed exposure, the correlation at low levels was weaker even for blood benzene and urinary MA (r = 0.6). According to the results in the benzene factory the exposure to pure benzene at the level 1 cm3/m3 (3.25 mg/m3) TWA gave: the blood benzene value about 110 nmol/l (8.6 micrograms/l), MA 23 mumol/l (3.3 micrograms/l) or 2.0 mg/g creatinine, S-PMA 58 micrograms/g creatinine or 0.4 mumol/l (95.7 micrograms/l), benzene in urine 499 nmol/l (39 micrograms/l), and benzene in the exhaled air 2.8 nmol/l (0.2 microgram/l). In general, the measurement of benzene in blood and in exhaled air, as well as benzene and its metabolites MA and S-PMA in urine, all gave similar results. However, at low exposure level (< 1 cm3/m3) the most reliable analyses were MA in urine and benzene in blood.

Acetylcysteine↗
PubMed1997

Analysis of aluminium in serum and urine for the biomonitoring of occupational exposure.

A reliable and sensitive graphite furnace atomic absorption spectrometry (GFAAS) method with Zeeman background correction was developed for the analysis of aluminium in serum and urine in the biological monitoring of aluminium exposure. The method is based on platform atomisation in pyrolytically coated graphite tubes after fourfold dilution with nitric acid. For serum analysis, a matrix matched standard curve is prepared and for urine the method of standard additions is used. The within-run imprecision (C.V.) for serum and urine was 3% and 5%, and the between-day imprecision, 6% and 7.2%, at a concentration level of 4.0 mumol/l. The between-day imprecision for urinary aluminium was 15.7% at a concentration level of 0.24 mumol/l. The detection limits were 0.02 mumol/l for serum and 0.07 mumol/l for urine. During 1 year of participation in TEQAS external quality assessment scheme of the Robens Institute for Health and Safety (Guildford, UK) for serum aluminium the maximum cumulative performance score was achieved. For urinary aluminium a certificate in the external quality control scheme of the German Society of Occupational Medicine was obtained. The mean concentration of aluminium in a non-exposed population, who did not use antacid drugs, was 0.06 mumol/l (S.D. 0.03, range 0.02-0.13, n = 21) in serum, and 0.33 mumol/l (S.D. 0.18, range 0.07-0.82, n = 44) in urine. The upper reference limit for aluminium in a healthy, non-exposed population was estimated to be 0.1 mumol/l in serum and 0.6 mumol/l in urine.

Adult↗
PubMed1997

Exposure to soluble nickel in electrolytic nickel refining.

Past and present exposure to nickel was studied in an electrolytic nickel refinery, where an increased incidence of nasal cancer had been reported, using nickel analyses in air, blood and urine. Genotoxic effects were studied using analysis of micronuclei from acridine orange-stained smears from the buccal mucosa of the workers. Workers used respirators or masks in tasks where the exposure was expected to be high. Inside the mask, nickel concentrations were 0.9-2.4 micrograms m-3 in such tasks. In those tasks where masks were not used, nickel concentrations in the breathing zone were 1.3-21 micrograms m-3. Air-borne nickel concentrations (stationary sampling) varied between 230 and 800 micrograms m-3 in 1966-1988 with no systematic change; thereafter lower concentrations (170-460 micrograms m-3) have been observed. After-shift urinary concentrations of nickel were 0.1-2 mumol l-1; they showed no correlation with nickel concentrations in the air. Concentrations of nickel in the urine were still elevated after a 2-4 week vacation. The frequency of micronucleated epithelial cells in the buccal mucosa of nickel refinery workers was not significantly elevated by comparison with referents. No relationship was observed between micronucleus frequencies and levels of nickel in air, urine or blood.

Air Pollutants, Occupational↗
PubMed1997

Occupational exposure to nickel salts in electrolytic plating.

An occupational hygiene survey was made in 38 nickel plating shops in Finland and exposure to nickel was studied by means of biological measurements and, in three shops, by using air measurements. The average after-shift urinary nickel concentration of 163 workers was 0.16 mumol l.-1 (range 0.001-4.99 mumol l.-1). After the 1-5 week vacation the urinary nickel concentration was higher than the upper reference limit of non-exposed Finns indicating that a part of water-soluble nickel salts is accumulated in the body. Urinary nickel concentrations in the shops considered clean in the industrial hygiene walk-through were not different from those observed in the shops considered dirty. The correlation between the concentrations of nickel in the air and in the urine was low, and the amount of nickel excreted in the urine exceeded the calculated inhaled amounts, indicating exposure by other routes such as ingestion.

Adult↗
PubMed1997

Hand dermatitis and allergic patch test reactions caused by nickel in electroplaters.

A worksite survey was conducted in all 38 Finnish electroplating plants. All workers (n = 163) who worked with nickel plating (bath workers, hangers and solution makers) were interviewed with a questionnaire about symptoms of nickel dermatitis, hand dermatitis, and about protective measures, atopy, etc. Patch testing with nickel sulfate was done with the TRUE TestTM method. All the workers, 94 men and 69 women, answered the questionnaire. The mean age of women was 41.1 years, and of men 43.1 years, respectively. Men had longer occupational exposure to nickel (14 years) than women (10 years). Most workers used protective gloves. 35% of women and 30% of men reported present or past hand dermatosis. 19% reported a history of atopic dermatitis. 15% of women (n = 8) and 4% (n = 2) of men had an allergic patch test reaction to nickel sulfate. 70% of those with an allergic patch test reaction to nickel reported past or present hand eczema. The prevalence of nickel allergy among the electroplaters was similar to that of patients in patch test clinics in Finland. An allergic patch test reaction to nickel sulfate does not necessarily oblige an electroplater to change jobs.

Adult↗
PubMed1997

Effects of low level exposure to lead on neurophysiological functions among lead battery workers.

OBJECTIVES: Assessment of neurophysiological functions in workers with low level exposure to lead and evaluation of the efficacy of bone lead measurements in the prediction of effects of lead. METHODS: Exposure to lead of 60 workers from a lead battery battery factory was estimated from historical blood lead measurements and analysis of lead in the tibial and calcaneal bones with x ray fluorescence. Peripheral and central nervous system functions were assessed by measuring conduction velocities, sensory distal latencies, sensory amplitudes, and vibration thresholds as well as by quantitative measurement of the absolute and relative powers and mean frequencies of different electroencephalograph (EEG) channels. RESULTS: Sensory amplitudes, and to a smaller degree sensory or motor conduction velocities, showed a negative correlation with long term exposure to lead, most clearly with integrated blood lead concentration and exposure time. Vibration thresholds measured in the arm were related to recent exposure to lead, those measured in the leg to long term exposure. The alpha and beta activities of the EEG were more abundant in subjects with higher long term exposure to lead. Calcaneal lead content reflected short term exposure, tibial lead content reflected long term exposure. Blood lead history showed a closer relation with effects of lead than the tibial or calcaneal lead concentrations. CONCLUSIONS: Vibratory thresholds, quantitative EEG, and to a smaller extent the sensory amplitude, provide sensitive measures of effects of lead in occupationally exposed adults. Most accurate estimates of health risks induced by lead can be obtained from a good history of blood lead measurements. If such a history of blood lead concentrations is not available, analysis of bone lead may be used for the assessment of health risks.

Adult↗
PubMed1996

Respiratory health of workers exposed to low levels of chromium in stainless steel production.

OBJECTIVES: To determine whether occupational exposure to chromite, trivalent chromium, or hexavalent chromium causes respiratory diseases, an excess of respiratory symptoms, a decrease in pulmonary function, or signs of pneumoconiosis among workers in an integrated chain of stainless steel production. METHODS: This cross sectional study was carried out in 1993 and the inclusion criterion was a minimum of eight years of employment in the same production department. A self administered questionnaire was collected, and spirometry, measurement of diffusing capacity, chest radiography, and laboratory tests were carried out by a mobile research unit. RESULTS: There were 221 workers in the exposure groups and 95 in the control group. The average duration of employment was 18 years. No significant differences in the odds ratios (ORs) of the symptoms were found between the exposure and the control groups. In a logistic regression analysis age and smoking significantly explained the occurrence of most of the respiratory symptoms. The smokers in the chromite group had significantly lower forced vital capacity (FVC), forced expiratory volume in one second (FEV1), and diffusing capacity than the corresponding values of the control group. The analysis of variance between study groups, smoking, and exposure time, without modelling for interactions, showed that the chromite group had lower values for FVC, FEV1, and diffusing capacity than the other groups. The occurrence of small opacities was more frequent on the chest radiographs of the workers in the chromite group. CONCLUSIONS: An average exposure time of 18 years in ferrochromium and stainless steel production and exposure to dusts containing low concentrations of hexavalent or trivalent chromium do not lead to any respiratory changes detectable by lung function tests or radiography nor to any increase in symptoms of respiratory diseases. The lung function values were lower and the occurrence of radiological findings was more frequent among the workers from the chromite mine than among the controls. The difference was partly caused by differences in age and smoking habits, but evidently also partly by higher exposures more than two decades ago or by the fibrous components of the dust.

Adult↗
PubMed1996

Quality assurance in occupational and environmental laboratory medicine.

In a medical laboratory service, quality assurance (QA) concerns all those actions necessary to provide confidence that the results of laboratory tests will satisfy defined standards for quality. Taking into account the type of testing concerned and the techniques involved, quality assurance will encompass all steps taken to ensure that laboratory results are reliable. It covers the use of scientifically and technically sound practices for laboratory investigations, including selection, collection, transport, identification, storage, preparation and manipulation of specimens and recording, reporting and interpretation of the results. QA refers also to other activities designed to improve the reliability of investigations such as staff training and management, evaluation of the adequacy of the laboratory environment, maintenance and calibration of instruments and the use of technically validated and properly documented methods. All these activities should be described in a quality manual. This document is a prerequisite to obtain certification of the quality system or laboratory accreditation, according to the International Standard ISO 29000 series or the European Standard EN 45001, respectively.

Accreditation↗
PubMed1996

FIOH external quality assurance scheme for organic solvent metabolites.

The scheme consists of analyses for phenol,2,5-hexanedione, and mandelic, trichloroacetic and methylhippuric acids in urine. The present participants are 31 laboratories from 14 countries. Samples are prepared by pooling urine obtained from occupationally exposed workers or by spiking with appropriate pure metabolites. Four sets of samples at two concentration levels for each analyte are distributed annually. The report includes information on the arithmetic means, standard deviations and CVs for overall results and separately for different methods. During the last three years, the CVs have varied rather non systematically, being 21-31% for mandelic acid, 24-26% for trichloroacetic acid, 24-35% for phenol, 55-110% for 2,5-hexanedione and 44-50% for methylhippuric acid.

Environmental Monitoring↗
PubMed1995

Effect of cytochrome P450 isozyme induction and glutathione depletion on the metabolism of CS2 to TTCA in rats.

Analysis of 2-thiothiazolidine-4-carboxylic acid (TTCA), a metabolite of carbon disulfide (CS2), is used in the biological monitoring exposure to CS2 at work. In order to clarify the metabolic reasons for individual variation in the urinary excretion of TTCA, the latter was studied in rats pretreated with model cytochrome P450 (CYP) enzyme inducers or glutathione (GSH) depletors. Ethanol, phenobarbital (PB) or 3-methylcholanthrene (MC) did not increase 24-h TTCA output following CS2 inhalation (50 or 500 ppm, 6h). After oral dosing (10 mg/rat), PB had an inhibiting effect on the excretion rate of TTCA. Tissue GSH depletors phorone, L-buthionine-(RS)-sulfoximine (BSO) and diethylmaleate (DEM) decreased TTCA excretion in rats given an oral dose (10 mg/rat) of CS2. The initial inhibition by phorone and DEM was reversed after 6 h and from 12 h onward the TTCA in urine exceeded the control level, an effect not seen with BSO. The proportion of CS2 excreted in urine as TTCA within 24 h was 1.7% in control rats and 1% after BSO treatment, 1.3% after PB, 1.7% after acetone, 1.8% after MC, 2.0% after phorone and 2.5% after DEM treatment. The amount of TTCA in urine increased with the CS2 dose in a non-linear fashion: 1.6 mumol (50 ppm/6 h) vs. 4.9 mumol (500 ppm/6 h), and 0.2 mumol (1 mg/kg) versus 3.6 mumol (100 mg/kg).(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Inhalation↗
PubMed1995

Quality assurance in biomarker measurement.

Quality assurance (QA) concerns the validity of all the analytical processes (from collection of the samples to interpretation of the results). It is not an abstract concept but must be adapted to the different situations such as the different exposure levels, the different analytical methods, and the context of use (risk assessment procedures, research, routine determinations). The main requirements in QA programmes regard the control of all the known sources of preanalytical and analytical variations, while the instruments with which adequate QA can be implemented are the certified materials and the quality control programmes (quality manual, internal and external quality controls). Another important concept in QA is that measurements must be placed a different metrological levels: at the highest there are the methods (definitive, reference) to be used for assessing accuracy of routine methods. QA programmes should enable a grading of biomarkers (from experimental only to full evaluated) and of the laboratories in order to identify the significance of the test and to assess the level at which a laboratory could operate.

Biomarkers↗
PubMed1994

Biological monitoring today and tomorrow.

Biological monitoring is important in the assessment of both occupational exposure to chemical agents and the health risks involved. For some chemicals data from biological monitoring can be reliably translated into health risks, while for the majority it only indicates uptake. Several workplace chemicals can be analyzed from biological specimens, but no interpretation of health risk or exposure is possible. For such chemicals, comparing the results to data from similar industries may help to determine whether smaller levels of exposure are possible. The biggest problem with most biological monitoring is that no good interpretation is immediately available. This statement is equally true for classical specific analytical chemical analyses, nonspecific assays of exposure, and almost all effect monitoring. Health-based interpretation of biological monitoring will never become possible unless biological monitoring is performed (even in the absence of immediate interpretation) and the results are stored for future analysis in a retrievable and usable form.

DNA Damage↗
PubMed1994

Reference limits in occupational toxicology.

Two categories of reference limits can be discerned in biological monitoring: The first category identifies individuals who have been exposed to a toxic agent at work, and is based on the distribution of the concentration of the agent or its metabolite in the population that has not been exposed to the agent at work. The second category, for which the term biological action level (BAL) is proposed, provides a guideline on the level of exposure that is acceptable. These levels may be either directly health-based or derived from good working practices. Thus BAL is a biological equivalent for the generic term occupational exposure limit. BAL should be independent of legal overtones, and implies that workers' exposure should be reduced.

Environmental Monitoring↗
PubMed1993

Analysis and stability of phenylglyoxylic and mandelic acids in the urine of styrene-exposed people.

In this work a high-performance liquid chromatographic method is described that is reliable and practical for use in routine biological monitoring of exposure to styrene. The method uses a modern diode array detection technique by which mandelic and phenylglyoxylic acids can be measured simultaneously using different wavelengths. The liquid chromatographic method was compared to a gas chromatographic method developed for the analysis of mandelic, phenylglyoxylic and para-hydroxymandelic acids. The methods gave results consistent with each other. These two methods were then used to check the stability of the main metabolites of styrene, especially of phenylglyoxylic acid, in urine samples stored at +6 degrees C or at -18 degrees C for periods up to 70 days. None of the frozen samples showed any significant decrease in the phenylglyoxylic acid concentration, whereas at 6 degrees C one of the samples showed a reduction of 46% after 1 month.

Chromatography, Gas↗
PubMed1993

Normal concentrations of chromium in serum and urine--a TRACY project.

The validity of "normal" concentrations for total chromium in serum and urine (S-Cr and U-Cr, respectively) in papers published mainly in the last decade were evaluated and graded by two investigators according to TRACY criteria. The results were in close agreement. Because of possible contamination during sampling from stainless steel needles, the description of the sample collection method was considered important. Documentation of analytical quality control was emphasized. The chromium concentrations were categorized according to nonoccupational conditions that could influence the levels. Eighty-seven publications reporting chromium concentrations in blood and 58 on U-Cr were evaluated, 53 dealing with S-Cr and 41 with U-Cr being found suitable for the TRACY project. In selected publications the arithmetic mean values presented for S-Cr and U-Cr in individuals with no known exposure were within the following ranges: 1-3 nmol.1-1 for S-Cr and 2-10 nmol.1-1 or 0.2-1 mumol.mol creatinine-1 for U-Cr.

Chromium↗
PubMed1992

Assessment of exposure to carbon disulfide in viscose production workers from urinary 2-thiothiazolidine-4-carboxylic acid determinations.

The follow-up of environmental carbon disulfide (CS2) exposure and urinary excretion of 2-thiothiazolidine-4-carboxylic acid (TTCA) among 20 operatives over a 4-day working week in two viscose producing factories confirmed earlier observations that TTCA is a sensitive and reliable indicator of exposure to CS2. Exposure to as low as 0.5-1.0 ppm (1.6-3.2 mg/m3) of CS2 (8-hour time-weighted average [TWA]) was associated with detectable amounts of TTCA in end-of-shift urine. Moreover, the excretion of TTCA, relative to estimated CS2 uptake, appeared surprisingly constant in the studied work force. Approximately 3% (range 2-6.5%) of absorbed CS2 was detected in urine as TTCA. The proportional TTCA excretion did not show dose dependency in the estimated CS2 dose range which varied by about 20-fold. TTCA elimination exhibited both a fast (T 1/2 6 hour) and a slow (T 1/2 68 hour) phase. The slow elimination is compatible with a high lipid solubility and reversible protein binding of CS2. Consequently, urinary excretion of TTCA, relative to CS2 exposure, increased by about a third during the workweek. Urinary TTCA concentration of 4.5 mmol/mol creatinine in a postshift sample corresponded to a TWA exposure to 10 ppm CS2 towards the end of the working week.

Adult↗