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Biomedical subjects

P O Droz

Publications and source records attributed to P O Droz.

At least 19 recordsLinked to original sources
PubMed1992

Occupational exposure of truck drivers to dust and polynuclear aromatic hydrocarbons: a pilot study in Geneva, Switzerland.

The exposure to dust and polynuclear aromatic hydrocarbons (PAH) of 15 truck drivers from Geneva, Switzerland, was measured. The drivers were divided between "long-distance" drivers and "local" drivers and between smokers and nonsmokers and were compared with a control group of 6 office workers who were also divided into smokers and nonsmokers. Dust was measured on 1 workday both by a direct-reading instrument and by sampling. The local drivers showed higher exposure to dust (0.3 mg/m3) and PAH than the long-distance drivers (0.1 mg/m3), who showed no difference with the control group. This observation may be due to the fact that the local drivers spend more time in more polluted areas, such as streets with heavy traffic and construction sites, than do the long-distance drivers. Smoking does not influence exposure to dust and PAH of professional truck drivers, as measured in this study, probably because the ventilation rate of the truck cabins is relatively high even during cold days (11-15 r/h). The distribution of dust concentrations was shown in some cases to be quite different from the expected log-normal distribution. The contribution of diesel exhaust to these exposures could not be estimated since no specific tracer was used. However, the relatively low level of dust exposure dose not support the hypothesis that present day levels of diesel exhaust particulates play a significant role in the excess occurrence of lung cancer observed in professional truck drivers.

Air Pollutants, Occupational↗
PubMed1992

Quantification of biological variability.

Pharmacokinetic models are usually developed to describe the kinetic behaviour of the chemical compounds in an average human body. There are however many situations were the effects of variations in a given pharmacokinetic parameter would be of interest. For example, in biological monitoring, the variability of biological data is a critical parameter when relating air and biological measures of an individual exposure. This paper reviews two possible approaches for the simulation of such variability in occupational pharmacokinetics. In the first, a simple one-compartment model is used together with statistical distributions for the intake and elimination of the compounds involved. Based on realistic distributions, this simple model is applied to the comparison of biological and air monitoring to estimate workers' exposure. The second involves a seven-compartment physiologically based pharmacokinetic model, which includes provision of the means to input satistical distributions for some of the parameters: exposures, physical workload, body height, body weight, liver function and renal function. It makes it possible to predict the pharmacokinetic response of groups of workers, who differ in their exposures and in their physiological parameters. Realistic statistical distributions are then used to describe biological monitoring variability. The advantages and disadvantages of both the simple pharmacokinetic model and the physiological model are discussed in the context of predicting and understanding variability in occupational situations. Other potential developments are also considered.

Environmental Monitoring↗
PubMed1990

Dermal absorption potential of industrial chemicals: criteria for skin notation.

A dermal penetration rate (flux), predicted from physical properties of 132 chemicals, is suggested as an index of the dermal absorption potential of industrial chemicals. The prediction is designed for organic nonelectrolytes. Two reference values are recommended as criteria for skin notation: 1) dermal absorption potential, which relates to dermal absorption raising the dose of nonvolatile chemicals or biological levels of volatile chemicals 30% above those observed during inhalation exposure to TLV-TWA only--dermal absorption of chemicals belonging to this category should be considered when data obtained by biological monitoring are interpreted; and 2) dermal toxicity potential, which relates to dermal absorption that triples biological levels as compared with levels observed during inhalation exposure to TLV-TWA only. Chemicals belonging in this category should carry a skin notation. The toxicity criteria may not be valid for chemicals whose TLVs are based on preventing irritation and discomfort.

Environmental Exposure↗
PubMed1989

Variability in biological monitoring of solvent exposure. I. Development of a population physiological model.

Biological indicators of exposure to solvents are often characterised by a high variability that may be due either to fluctuations in exposure or individual differences in the workers. To describe and understand this variability better a physiological model for differing workers under variable industrial environments has been developed. Standard statistical distributions are used to simulate variability in exposure concentration, physical workload, body build, liver function, and renal clearance. For groups of workers exposed daily, the model calculates air monitoring indicators and biological monitoring results (expired air, blood, and urine). The results obtained are discussed and compared with measured data, both physiological (body build, cardiac output, alveolar ventilation) and toxicokinetic for six solvents: 1,1,1-trichloroethane, trichloroethylene, tetrachloroethylene, benzene, toluene, styrene, and their main metabolites. Possible applications of this population physiological model are presented.

Adipose Tissue↗
PubMed1989

Variability in biological monitoring of organic solvent exposure. II. Application of a population physiological model.

A physiological population model is used to study the variability associated with the biological monitoring of solvent exposure. The model consists of a combination of a physiological compartmental model and statistical simulation technique. Variable components considered are: exposure concentration, physical workload, body build, liver function, and renal function. The model is applied to six solvents: trichloroethylene, tetrachloroethylene, methylchloroform, benzene, toluene, and styrene. Biological indicators and air monitoring are compared as predictors of exposure, both external and internal (uptake, brain concentration, reactive metabolite formation). It appears that the choice of the best indicator depends on the type of exposure which is to be predicted. The effects of the various factors, environmental, physiological, or metabolic, are quantified and discussed. It is shown that fluctuation in exposure plays a large part in the final variability of biological indicator results. Further improvements and applications of this population model are considered.

Benzene↗
PubMed1988

A direct reading method for chlorinated hydrocarbons in breath.

A direct reading method is described for the measurement of tetrachloroethylene and 1,1,1-trichloroethane in breath for concentrations ranging from 2.5 to 30 ppm. It is based on colorimetric detector tube technology and consists of a two-step procedure: 1) total breath sampling in a bag and 2) analysis of the bag's content by detector tubes for the solvent and carbon dioxide. The latter is used to take into account dead space dilution and possible hyper- or hypoventilation. The method is tested in volunteers experimentally exposed to tetrachloroethylene and 1,1,1-trichloroethane and in workers occupationally exposed to tetrachloroethylene. Its results are compared with a reference gas chromatographic method. The agreement between the methods is good, with a systematic proportional error of less than +13% for tetrachloroethylene. Repeated measurements show standard deviations ranging from 6% to 39% of the tested concentrations.

Breath Tests↗
PubMed1986

[Monitoring of persons exposed to perchloroethylene or styrene].

Forty-nine employees exposed to perchloroethylene (dry cleaning) and 41 employees exposed to styrene (fiber reinforced polyester) are compared to a control group of 68 persons. Symptoms such as dizziness, mouth dryness, fatigue, mucous membranes and skin irritation appear more frequently among the exposed groups, while liver and kidney functions remain unchanged. This study demonstrates that medical examination, industrial hygiene survey and biological monitoring can complement each other in the evaluation of work conditions.

Adult↗
PubMed1986

[Preventive examinations in the rotogravure printing industry].

One hundred and sixty rotogravure printing workers exposed mainly to toluene are compared (clinical examination, liver and kidney tests) to 38 unexposed workers. The exposure to toluene is assessed by personal air sampling at the workplace (mean: 54 ppm) and by analysis of hippuric acid in urine (mean: 1.86 g/g creatinine). Fatigue, alcohol intolerance, mouth dryness appear more frequently among the exposed subjects. Differences observed in liver tests are difficult to relate to toluene exposure. The additional eight-year health surveillance of 18 workers shows no significant changes in liver and kidney functions.

Adult↗
PubMed1986

Occupational exposure monitoring using breath analysis.

Breath analysis has been proposed on numerous occasions for monitoring solvent exposure. Nevertheless, it is still rarely used routinely because of difficulties in the methodology itself (sampling and analysis) and lack of data concerning its relationship to exposure dose. The various methods available today are briefly reviewed, compared, and discussed. Emphasis is on the simultaneous use of CO2 as a respiratory index. Two methods using this approach are presented. The advantages and limitations of breath analysis for occupational exposure monitoring are discussed using data obtained in experimental, field, and simulation studies. Benzene toluene, styrene, 1,1,1-trichloroethylene, and tetrachloroethylene are taken as examples of solvents showing various toxicokinetic properties. Finally, breath analysis is compared with other biological monitoring methods.

Air Pollutants, Occupational↗
PubMed1985

Human exposure to styrene. VI. Percutaneous absorption in human volunteers.

In order to estimate the importance of skin resorption of styrene, as compared to pulmonary absorption, nine male volunteers were exposed for 10 to 30 min by dipping one hand in liquid styrene. Urine and breath were sampled periodically for metabolites (mandelic and phenylglyoxylic acids) and styrene analyses respectively. The results obtained show that the rate of absorption of styrene through the skin is very low, averaging 1 +/- 0.5 micrograms/cm2 X min. This rate seems to be affected by the duration of exposure. In conclusion, this study shows that skin resorption plays only a minor role in most practical situations.

Adult↗
PubMed1984

[Industrial hygiene in hospitals].

This paper emphasizes the importance of occupational hygiene in the hospital. By taking into account the differences between hospital hygiene and industrial hygiene one realizes that these sciences are quite complementary. A few occupational stresses or hazards are described some of them being unspecific to the hospital and the other ones being specific i.e. they are not usually present in other industrial situations. Among these are anesthetic gases, ethylene oxide and cytostatic agents. Examples of results obtained during field surveys are given and briefly commented. The occupational hygienist is an important member of the team aiming at the protection of the workers' health in the hospital.

Anesthetics↗
PubMed1983

Human styrene exposure. V. Development of a model for biological monitoring.

The use of biological indicators to monitor workers' exposure to styrene requires a good understanding of the kinetics of the solvent in the organism. The absorption, distribution and elimination of styrene (STY), as well as the kinetics of formation and excretion of its metabolites (mandelic [MA] and phenylglyoxylic [PGA] acids) are simulated using a mathematical model. The results obtained compare well with experimental data for pulmonary (STY) and urinary (MA and PGA) excretion obtained during controlled human exposures. The model is then used to predict the behaviour of STY, MA and PGA during repeated occupational exposure. It is shown that the results are comparable to the data collected during field surveys in the polyester industry, if the level of physical activity of the workers is taken into account. This latter parameter appears to have a great influence on the urinary excretion of the metabolites. Based on the results obtained, biological limits of exposure are proposed (referenced to a TLV [threshold limit value] of 50 ppm) for MA and MA + PGA excretions in urine collected at the end of the shift (800 and 1000 mg/g creat.) and the next morning (150 and 300 mg/g creat.). Their validity is tested against experimental data obtained under field conditions.

Environmental Exposure↗
PubMed1982

1,1,1-Trichloroethane exposure, biologic monitoring by breath and urine analyses.

Absorption and excretion of 1,1,1-trichloroethane, as well as the kinetics of formation and elimination of trichloroethanol (TCE) and trichloroacetic acid (TCA) were simulated by a mathematical model. The results of this model were compared with experimental one on pulmonary elimination of the solvent and urinary excretion of the metabolites. The influences of duration and repetition of exposure on the pulmonary and urinary eliminations were studied. A tentative method of biologic monitoring is proposed. Theoretically, the most suitable method of biologic monitoring is proposed. Theoretically, the most suitable method to estimate the exposure is by two determinations, before and after a work shift. Following this procedure, analysis of TCE in the urine is more sensitive than determination of 1,1,1-trichloroethane in the breath. As an indicator of exposure risk, TCA is not considered sensitive enough if variations in the inspired concentration occur.

Breath Tests↗