MANOTA: a promising bifunctional chelating agent for copper-64 immunoPET

A comparison of four bifunctional chelating agents showed superior behaviour of a new NOTA derivative for ⁶⁴Cu labelling of antibody fragments.

Exposure to carcinogenic polycyclic aromatic compounds and health risk assessment for diesel-exhaust exposed workers

OBJECTIVES

Workers' exposure to diesel exhaust in a bus depot, a truck repair workshop and an underground tunnel was determined by the measuring of elemental carbon (EC) and 15 carcinogenic polycyclic aromatic compounds (PACs) proposed by the US Department of Health and Human Services/National Toxicology Program (NTP). Based on these concentration data, the genotoxic PAC contribution to the diesel-exhaust particle (DEP) lung-cancer risk was calculated.

METHOD

Respirable particulate matter was collected during the summer and winter of 2001 (except for in the underground situation) and analysed by coulometry for EC and by GC-MS methods for PACs. The use of potency equivalence factors (PEFs) allowed the studied PAC concentrations to be expressed as benzo[a]pyrene equivalents (B[a]P(eq)). We then calculated the lung-cancer risk due to PACs and DEPs by multiplying the B[a]P(eq) and EC concentrations by the corresponding unit risk factor. The ratio of these two risks values has been considered as an estimate of the genotoxic contribution to the DEP cancer risk.

RESULTS

For the bus depot and truck repair workshop, exposure to EC and PACs has been shown to increase by three to six times and ten times, respectively, during winter compared to summer. This increase has been attributed mainly to a decrease in ventilation during the cold. With the PEF approach, the B[a]P(eq) concentration is five-times higher than if only benzo[ a]pyrene (B[a]P) is considered. Dibenzopyrenes contribute an important part to this increase. A simple calculation based on unit risk factors indicates that the studied PAC contribution to the total lung-cancer risk attributed to DEPs is in the range of 3-13%.

CONCLUSIONS

The 15 NTP PACs represent a small but non-negligible part of lung-cancer risk with regard to diesel exposure. From this point of view, the dibenzopyrene family are important compounds to be considered.

Sampling and analysis of carbon in diesel exhaust particulates--an international comparison

OBJECTIVES

The European Co-ordination on Diesel Soot Exposure (ECDSE) working group organised a laboratory inter-comparison which integrated both the sampling and the analytical determination. The aim was to gain more information on the performance of the methods for the determination of diesel particulate matter at workplaces and on their comparability, and to also confirm that the requirements of the European standard EN 482 are fulfilled for this analytical procedure.

METHODS

Sampling was carried out in a diesel aerosol test chamber where participants used their own sampling devices. Overall, ten sampling exercises at two different concentration levels were performed and both personal air sampling systems and stationary samplers were used. The analytical determination was performed according to the laboratory's own standard procedure.

RESULTS

There was good agreement between the laboratories for the determination of organic carbon (OC), elemental carbon (EC) and total carbon (TC). Almost all the results when expressed as a coefficient of variation were in the range +/-30% of the overall means. The results also showed that the coefficient of variation for OC was approximately twice the coefficient of variation for EC. This is not too critical, because existing occupational exposure levels (OELs) are based on the measurement of EC.

CONCLUSIONS

The inter-comparison showed that existing analytical procedures for the determination of diesel particulate matter at workplaces fulfil the requirements of European standard EN 482. Both personal air samplers and stationary samplers give comparable results. The parameters for the analytical determination are not critical within the range of parameter values presented in this article. Additionally, it may be concluded that the diesel aerosol test chamber used in this exercise is well suited for producing an atmosphere containing a constant and reproducible level of diesel particulate matter.

[Bidirectional cell traffic between mother and fetus: new insights in pediatric and adult disorders]

There is a heavy traffic of cells and DNA through the placenta during pregnancy. The rate of fetal cells in the maternal blood is correlated with abnormalities, such as aneuploidy and pre-eclampsia. Studying and quantifying these cells could improve antenatal diagnosis techniques, especially for Down syndrome. Maternal-fetal microchimerism is frequently observed in several auto-immune diseases in adulthood, such as systemic scleroderma. Studies suggest a rather allo-immune pathophysiology, involving maternal-fetal HLA compatibility. Microchimerism is also found in auto-immune diseases in children. Thus, the cells traffic offers new insights for antenatal diagnosis techniques and pathophysiology of auto-immune diseases.

Further round-robin tests to improve the comparability between laboratories of the measurement of carbon in diesel soot and in environmental samples

OBJECTIVES

An informal European coordination group organized two round-robin tests on filters collected from environmental, workplace and diluted diesel emissions. Previous inter-laboratory comparisons have shown that experimental samples give reasonably good results in terms of the dispersion around the mean, from all the participating laboratories. However, there were significant differences between the laboratories owing to a narrow distribution of the results within a single laboratory. In order to gain a better understanding of the differences obtained between the laboratories, it was decided to carry out more round-robin tests and to investigate further the possible factors which may influence the results.

METHODS

The first round-robin (RRT3) was performed on six different samples (eight replicates) analyzed by ten laboratories. The range of loading was 40 to 138 micrograms cm-2 of total carbon (TC). Laboratories used their own thermal procedure parameters. The second round-robin test (RRT4) was performed on three different diluted diesel emissions (two replicates) samples analyzed by 13 laboratories. The range of loading was 21 to 37 micrograms cm-2 TC. Laboratories analyzed samples using imposed temperatures (500, 650 and 800 degrees C) and imposed duration (12 min).

RESULTS

Inter-laboratory coefficients of variation for diluted diesel emission samples were 10% for RRT3 and ranged from 6 to 19% for RRT4. The influence of the desorption temperature was clearly demonstrated and the results tended to show that a desorption temperature of 650 degrees C could be an acceptable compromise. The influence of the organic carbon/elemental carbon (OC/EC) ratio was shown to be insignificant with pure diesel soot samples.

CONCLUSIONS

It was expected that a significant improvement would be seen in the inter-laboratory dispersion by the use of a common standardized thermal desorption program, but the objectives of these RRTs were only partly reached. This paper provides new information that will be useful in the elaboration of a standardized procedure for the European Normalisation Centre (CEN TC 137 WG2--General requirements for measuring procedures).

Switzerland: the status of silicosis from the past to the end of the 20th century. Control and prevention

The silicosis issue in Switzerland is reviewed on the basis of data provided by Suva, the Swiss National Insurance Fund, in charge of law enforcement and of prevention. Pictures of the past period and nowadays consecutively to the occupational medicine surveillance and industrial hygiene practice showed that major improvements have been realized. In the 30's, a constant rise of new cases of silicosis has been observed every year. From 1940 to end of the 60's, a plateau was reached with about 200 to 300 cases per year. Since 1974, a significant decrease is observed, the annual number of new cases being about 100. Since 1989, the new cases level off at 30-50 per year due to drastic control measures and present announced cases are residuals of previous exposures. The number of annual deaths ranges at the unit level with a patient's life expectancy nearly equal to that of the general population. Prevention efforts however should be continued since the activities of concern have changed. Small enterprises with a limited number of personnel dispersed throughout the country, working in the sectors of stone cutting and grinding, civil engineering and cleaning of building surfaces make prevention difficult and may lower its efficiency. In addition, information should also reach categories of individual workers like professional pottery crafstmen or leisure-exposed persons.

Assessment of occupational exposure to diesel fumes--parameter optimization of the thermal coulometric measurement method for carbon

'Elemental' carbon (EC) is used as a surrogate to assess occupational exposure to diesel soot. EC thermal analysis needs complete desorption of organic compounds from the soot particles prior to analysis in order to minimize positive interferences and artefacts. The desorption of the organic compounds can be considered as the major step which influences the reliability of the EC determination. A systematic study was carried out to investigate the different parameters of influence such as desorption temperature, desorption duration, heating rate and type of the sample on the desorption efficiency. It was found that temperature and duration are the major parameters of influence on the desorption efficiency. The influence of the sample load can be seen as a measure of the pyrolysis susceptibility of the sample. An optimized temperature program is proposed.

International round robin tests on the measurement of carbon in diesel exhaust particulates

OBJECT

Diesel soot has been recognized as probably carcinogenic to humans. Elemental carbon (also called black carbon) in soot is considered at the moment as the most significant surrogate to be measured for assessing the exposure to this pollutant. Its analysis is done by combustion in an oven and determination of the CO2 formed, after elimination of the organic fraction of the soot by heating and/or by solvent extraction. The analysis allows determination of both fractions of the soot: "elemental carbon" (EC) and organic carbon (OC). The sum of EC and OC is called TC (total carbon).

METHOD

An informal European coordination group organized two round robin tests on filter samples collected from diluted diesel emissions. The first round (RRT1) was performed on 13 different samples analyzed by ten laboratories. The range of loading was 2.5 to 150 micrograms/cm2 of EC. No evaluation of the precision within laboratories could be made since each laboratory gave only one result per sample. Therefore a second round (RRT2) was organized with two samples and a blank filter sent in several portions to 11 laboratories. It should be stressed that each laboratory used its own method and that no standardization was planned at this stage.

RESULTS

Results of RRT1 showed that the coefficient of variation between laboratories decreased with higher loading and was around 10% to 15% for EC above about 20 micrograms/cm2. Dispersion of the results varied and it appeared that the way OC is removed from the soot is probably the most important factor of influence. The correlation between the laboratories was good as a whole but some systematic differences could be detected. Besides the different techniques to remove the organic carbon, the pretreatment of the filter by HCl (either as a vapor or as a solution) to remove the inorganic carbonates (potential interference sources), is probably also a significant factor of influence in the dispersion of the results between laboratories. It is not yet clear from these results whether the "environmental" laboratories give different results from the "occupational" laboratories, but it is clear that their objectives differ since for the "environmentalists", EC is not a specific marker of diesel emmissions, in contrast to the "occupationalists".

CONCLUSION

It can be concluded that, although significant differences exist between laboratories they can be attributed mainly to the narrow distribution of the results within a single laboratory, and that the overall agreement of the results for EC and TC is fairly good. These results obtained with pure diesel engine emissions, should be complemented by field samples, but they have already achieved relevant findings in the performance of the procedures used to assess exposure to diesel soot.

Ubiquitous fiber exposure in selected sampling sites in Europe

OBJECTIVES

This study evaluates personal exposure to respirable inorganic and organic fibers during normal human lifetimes and assesses the order of magnitude of the contribution of inorganic fibers other than asbestos to total fiber exposure from man-made and natural sources.

METHODS

Four groups (suburban schoolchildren, rural retired persons, office workers, and taxi drivers), with five persons per group, were monitored for 24 h four times during one year. Personal sampling pumps collected airborne dust on gold-precoated Nuclepore filters. The fibers were analyzed for fiber sizes specified by the World Health Organization.

RESULTS

The geometric mean concentrations ranged from 9000 fibers.m-3 (office workers) to 20000 fibers.m-3 (schoolchildren) for organic fibers, and from 600 fibers.m-3 (taxi drivers) to 4000 fibers.m-3 (schoolchildren) for gypsum fibers. For other inorganic fibers the concentrations were around 5000 fibers.m-3. The contribution of fibers with an elemental composition similar to that of man-made vitreous fibers (MMVF) was less than about one-quarter of the content of other inorganic fibers. The fiber size distributions were uniform across the groups, and the organic fibers were the longest and thinnest nonasbestos fibers.

CONCLUSIONS

Lifetime exposure to fibers can be ranked as organic fibers > other inorganic fibers > fibers with an elemental composition similar to MMVF > MMVF. Information on the biological effects of fibers is difficult to interpret for use in assessing the health risk from exposure to low levels of ubiquitous fibers, and there is a lack of knowledge on the effects of organic fibers.

Time trend and determinants of blood lead levels in a Swiss population over a transition period (1984-1993) from leaded to unleaded gasoline use

This study analyzes the trend and determinants of blood lead levels in a Swiss region (population 770,000) over the 10-year period following the introduction of unleaded gasoline in 1985. The consumption of unleaded fuel increased rapidly, accounting in 1988 for 36% and in 1992 for 65% of all gasoline sales. Blood lead levels were measured in three representative samples (n = 1700) of the adult population within the framework of a health examination survey carried out in 1984/1985, 1988/1989, and 1992/1993. The geometric mean blood lead levels were, respectively, 0.59, 0.42, and 0.33 mumole/liter in men, 0.41, 0.29, and 0.25 mumole/liter in women. Similar trends have been observed across all age groups, occupational classes, and categories based on smoking, drinking, and dietary habits. The overexposure of city residents, in comparison to village residents, fades out over the observation period. These findings suggest that the changeover from leaded to unleaded gasoline has been the major cause of the blood lead decline. Wine drinking, cigarette smoking, and age appear to be significant determinants of blood lead for both sexes in all three surveys. In contrast, the association is inverse for milk consumption. The multivariate regression analysis shows that wine drinking remains the most important predictor of blood lead, whereas the influence of age increases with time and overcomes the effect of smoking in the third survey.

Hydrocarbon exposure, hypertension and kidney function tests

Control and hydrocarbon exposed workers participated in a cross-sectional study about the nephrotoxicity of chronic hydrocarbon exposure. Different markers of glomerular and tubular function as well as the celluria were examined and compared. The results show that the interaction between hypertension and hydrocarbon exposure has an influence on the kidney function. For the clearance the interaction age-exposure seems to play a more important role than age or exposure alone. The most useful markers appear to be the albuminuria, the N-acetyl-beta-D-glucosaminidase activity, the retinol-binding-protein concentration and the creatinine clearance.

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.

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.

[Analysis of tremor: methodology and clinical perspectives. Preliminary results]

A method of hand tremor measurement is presented in which tremor is recorded as a vibration and analyzed by Fourier transformation. The spectral analysis is then processed by computer. This technique is applied to two groups of volunteers in order to study its reproducibility in various conditions.

[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.

[Silicosis. Current problems. Evaluation of dust in the occupational environment]

The evaluation of airborne dust in the occupational environment is one of the most important tasks of the industrial hygienist. The topic is reviewed in three parts. First, the main properties of the hazard to be evaluated (in this case airborne particulates) are outlined, a knowledge of these being a basic prerequisite. A few aspects of this wide field are described. The second part deals with the sampling problem, which is extremely tricky due to the difficulty of sampling airborne particulates without altering their initial state in some way (size distribution, chemical composition etc.). The problem of sampling representativity is illustrated by a few examples. Thirdly, actual evaluation (including methods of detection and analysis, and interpretation of results) is dealt with in the same way, i.e. by demonstrating its complexity with the aid of a few examples. In conclusion, assessment of exposure to airborne solid or liquid contaminants, to determine, for example, whether a health hazard exists, can only be carried out by a specialist with the necessary knowledge and experience.

Value of the simultaneous determination of PCO2 in monitoring exposure to 1,1,1-trichloroethane by breath analysis

Eight volunteers were exposed for eight hours to about 200 ppm of 1,1,1-trichloroethane. On the next morning five series of five alveolar samples were collected for the simultaneous determination of PCO2 and 1,1,1-trichloroethane concentration. Three different methods of sampling were used: voluntary hyperventilation, 10-s breathholding, and "standard." A linear relationship between the alveolar concentrations of both gases was observed in all subjects. Expired air was also collected in two subjects and an analogous relationship was observed. Also the Bohr dead space was found to be of similar size for CO2 and for 1,1,1-trichloroethane. In the monitoring of solvent exposure by breath analysis it is suggested that the results should be corrected for hyperventilation or hypoventilation and for dilution of alveolar air with dead space air by a proportional adjustment of the solvent concentration at the mean normal adveolar PCO2 or by disregarding the samples with a PCO2 outside normal range. The PCO2 determination in 40 unselected workers has shown that in more than a third of them, to monitor exposure by breath analysis would have been of little meaning without such an adjustment or rejection criteria.

[Problems caused by asbestos]

Asbestos has become a pollutant of ambiant air and there is a lack of informations allowing a reliable evaluation of the health risk related to the levels of concentrations found in the community. Biological significance of short fibres, analytical methodology and permissible levels are discussed under the view of the future needs for research.

[Evaluation of occupational chromium exposure through the determination of urinary chromium]

Determinations of urinary chromium on 26 workers from 6 chromium electroplating workshops are presented and discussed in relation with results of airborne chromium. Rapid apparition of chromium in urine after the beginning of exposure tends to show that urinary analysis are a convenient test for the biological monitoring of chromium exposure.

[The new center for environmental research at the Institute for Social and Preventive Medicine, University of Lausanne]

The organisation and the services of the new Research Center for Occupational Environment and Chemical Pollutants are described and commented. The advantages of this original structure for the monitoring and the prevention of health hazards on a community level are emphasized.

[Application of industrial hygiene principles as exemplified in a chromium plating plant]

Recognition, evaluation and control of hazards were carried out in a typical case where chromium was the major pollutant. It was also emphasized that industrial hygiene is necessary in the prevention of occupational diseases.

[Mercury levels found in fishermen of Lake Geneva]

This paper presents an evaluation of the mercury levels found in a population eating principally fish coming from the Lake of Geneva. A good correlation exists between the blood mercury level and the amount of fish ingested weekly. Interpretation of the results shows that the threshold of fish comsumption should be about 1.4 kg per week and per person.

Simple method to determine the efficiency of a cream used for skin protection against solvents

Guillemin, M., Murset, J. C., Lob, M., and Riquez, J. (1974).British Journal of Industrial Medicine,31, 310-316. Simple method to determine the efficiency of a cream used for skin protection against solvents. Most of the industrial organic solvents coming into contact with the skin are absorbed through it and enter the blood. They can then be detected in the breath, the analysis of which makes it easy to evaluate skin absorption. Such an evaluation can be made with and without the use of a skin protective (barrier) cream. A comparison of the results allows the efficiency of the cream to be tested. An example of the application of this method is described. The solvent was toluene and the cream tested was composed mainly of talc, glycerol, and water. Ten male volunteers exposed their hands to liquid toluene for 10 minutes. The elimination of the solvent was followed by breath analysis up to 3 hours after the exposure. Two or more sets of exposure were made under different conditions with and without the protective cream. The results show a good standard of efficiency when the cream is carefully and deeply applied. The efficiency of the cream was determined by testing the difference between the decay curves obtained with and without the barrier cream. A relative efficiency was estimated as a percent diminution of solvent excretion by taking the excretion after exposure of unprotected skin as 100%. It is shown that skin absorption for toluene compared with lung absorption may be important and has to be estimated where total exposure is concerned. The method devised here appears to offer simplicity. It is presented as a laboratory test to show the intrinsic value of the cream but its applicability in the field is also considered.