Increased intima-media thickness in rayon workers after long-term exposure to carbon disulfide.

INTRODUCTION: Long-term exposure to carbon disulfide (CS2) is associated with increased cardiovascular mortality. However, previous studies on actual vascular changes showed heterogeneous results. Intima-media thickness of the carotid arteries (IMT) represents an established marker of atherosclerosis and a reasonable surrogate marker for cardiovascular risk. IMT was examined in a large cohort of CS2 exposed workers and the association with cumulative CS2 exposure analysed. METHODS: In a cross-sectional examination, 290 exposed and 137 non-exposed workers in a German rayon-manufacturing plant were assessed. Individual cumulative exposure was calculated from this assessment combined with the results of two cross-sectional studies in 1992 and 1999 and department-specific annual means of ambient (CECS2) and individual biological (CETTCA) monitoring results obtained 1992-2009. Furthermore, cumulative duration of working in CS2-exposed departments (CEYEARS) was calculated. Examination included assessment of a broad set of known cardiovascular risk factors and IMT measurement of the carotid arteries on both sides. Multiple linear regression analyses were performed with IMT as outcome and three variants of cumulative exposure (duration of exposure, cumulative CS2, and cumulative TTCA) as well as categorised maximum CS2 exposure, all adjusted for cardiovascular risk factors. RESULTS: All models of cumulative exposure showed a significant increase in IMT in the group with the highest level of exposure: CEYEARS > 20 years, ß = 0.045 mm; CECS2 > 270 ppm × years, ß = 0.052 mm; CETTCA > 33 mg/g creatinine × years, ß = 0.038 mm. Alternatively, addressing maximum exposure, workers with CS2 exposure of >10 ppm in at least 3 years exhibited a significant IMT increase (ß = 0.068 mm). CONCLUSION: Long-term CS2 exposure is an independent risk factor concerning IMT changes. The amount of IMT increase, in a similar range as that associated with other cardiovascular risk factors, might be clinically relevant.

Current and historical individual data about exposure of workers in the rayon industry to carbon disulfide and their validity in calculating the cumulative dose.

INTRODUCTION: The objective of the study was to investigate how exposure to carbon disulfide (CS2) in a rayon-manufacturing plant has changed within two decades and whether it is possible to calculate valid data for the individual cumulative exposure. METHODS: The data for CS2 concentration in air and biological exposure monitoring (2-thio-1,3-thiaxolidine-4-carboxylic acid (TTCA) in urine) from two cross-sectional studies, performed in 1992 (n = 362) and 2009 (n = 212) in a German rayon-manufacturing plant, were compared to data obtained from company-internal measurements between the studies. RESULTS: Using the data from the cross-sectional studies and company-internal data, cumulative external exposure and the cumulative internal exposure were calculated for each worker. External and internal CS2 exposure of the employees decreased from 1992 (medians 4.0 ppm and 1.63 mgTTCA/g creatinine) to 2009 (medians 2.5 ppm and 0.86 mg/g). However, company-internal CS2 data do not show a straight trend for this period. The annual medians of the company-internal measurement of external exposure to CS2 have varied between 2.7 and 8.4 ppm, in which median values exceeded 5 ppm generally since 2000. The annual medians for the company-internal biomonitoring assessment ranged between 1.2 and 2.8 mg/g creatinine. The cumulative CS2 exposure ranged from 8.5 to 869.5 ppm years for external exposure and between 1.30 and 176.2 mg/g creatinine years for the internal exposure. Significant correlations were found between the current air pollution and the internal exposure in 2009 but also between the cumulative external and internal CS2 exposure. CONCLUSIONS: Current exposure data, usually collected in cross-sectional studies, rarely allow a reliable statement on the cumulative dose, because of higher exposure in the past and of fluctuating courses of exposure. On the other hand, company-internal exposure data may be affected by non-representative measurement strategies. Some verification of the reliability of cumulative exposure data may be possible by testing the correlation between cumulative exposure data of external assessment and biological monitoring.

On the lookout for precursor lesions: where does dry skin end and slight hand eczema begin?

BACKGROUND: The prognosis of occupational hand eczema is strongly associated with its duration, severity, and the onset of treatment. OBJECTIVES: The study was aimed at characterizing skin eruptions that might be potential precursors of occupational hand eczema, their pattern, and typical sites in a population at moderate risk of hand eczema. PATIENTS/MATERIALS/METHODS: Eight hundred German male metal workers took part in a structured interview focused on their medical history combined with a dermatological examination of their hands, by use of the quantitative Hand Eczema Score for Occupational Screenings, with follow-up 1 year later. RESULTS: The most frequent lesions were erythema (91.8%), lichenification (98.8%), crusting (70%), and scaling (35%); all other lesions were relatively rare (15%). The distribution of lesions remained stable between baseline and follow-up. The areas most affected were knuckles, palms, and finger shafts (excluding tips). Interdigital regions were uncommonly affected in this sample. CONCLUSIONS: Erythema, lichenification, and crusting, indicating constant skin 'strain', can be regarded as precursor lesions for slight hand eczema, and should be monitored quantitatively. As other occupations, for example hairdressing, have different predilection sites, it can be concluded that the pattern of occupational hand eczema is strongly influenced by the distinct strain profile of an occupation.

Health inequalities according to plant size--comparison of small- and medium-sized enterprises.

OBJECTIVES: Assessing plant size-related differences based on self-reported working conditions and their influence on perceived symptoms at workplace. METHODS: A total of 799 metal workers from 9 small-sized enterprises (SE) and 10 medium-sized enterprises (ME) German metal working plants were interviewed in 2007/2008. Inclusion criteria were "wet work" and willingness to participate (response rate: 58% in ME, 67.7% in SE). RESULTS: Workers in SE complained more often of hand eczema (20.2% vs 13.8%) whereas workers in ME more frequently reported breathing problems (4.2% vs 0.9%). Work safety was higher in ME. CONCLUSIONS: The higher rate of skin impairment in SE might be explained by a lower level of work safety. However, the higher frequency of perceived respiratory symptoms in ME seems to contradict this assumption and except plant size there might exist another potential confounder, especially for breathing impairment.

Non-invasive bioengineering methods in an intervention study in 1020 male metal workers: results and implications for occupational dermatology.

BACKGROUND: Measurements of transepidermal water loss (TEWL) as an indicator of skin barrier function and colorimetry for quantifying erythema have been recommended for monitoring persons at risk of occupational hand dermatitis. OBJECTIVE: This study examines the practicability and usefulness of biophysical measurements at the workplace. PATIENTS/MATERIAL/METHODS: A sample of 1020 male metal workers was enrolled; 800 participants were followed up for 1 year. TEWL results and colorimetry (a* value), respectively, were used as effectiveness outcomes, comparing the findings in the four study arms (skin care, skin protection, both combined, and control group). RESULTS: At 1 year follow-up, the TEWL was slightly but significantly lower in the group of participants randomized for application of barrier cream alone, indicating a protective effect. However, addressing both the individual absolute change of a* value and the differences of TEWL (delta-TEWL) of the dominant hand over the study period, no significant difference was found between the four groups. CONCLUSIONS: Dermatological examinations at the workplace cannot be replaced by bioengineering techniques. The supplementary benefit is apparently low, possibly because of difficulties in achieving standardized measurement conditions and other technical reasons.

Spoilt for choice--evaluation of two different scoring systems for early hand eczema in teledermatological examinations.

BACKGROUND: Besides improving working conditions and using personal protective equipment, early detection is most important in managing work-related hand eczema. Implementing regular teledermatological skin screenings could be helpful, but none of the published hand eczema-scores has hitherto been used in teledermatology. OBJECTIVE: Testing and comparing two validated scores [Osnabrück hand eczema severity index (OHSI); hand eczema severity index (HECSI)] for their suitability in an occupational telemedical screening. PATIENTS/MATERIALS/METHODS: One hundred and twenty photographic records of the hands of 30 male wet workers were examined twice with each score. Results were tested for reproducibility, intra-observer reliability and inter-score-correlation. RESULTS: Examination time, mean score values, and score ranges reached did not differ significantly. The inter-score-correlation was moderate (correlation coefficients: 0.651 for first examination; 0.642 for second examination). In the qualitative assessment, the HECSI showed a better overall agreement between results of first and second examinations. CONCLUSIONS: Both scores are suitable for assessing the skin condition in a teledermatological setting. The comparability is limited to qualitative assessment, as the strictly objective OHSI measures the extent of hand eczema and the finer graduated HECSI measures the intensity of hand eczema, adding a subjective component. For assessing minimal skin changes, a scoring system that reduces subjective elements while at the same time it offers a differentiated grading is advisable.

Prevention of work-related skin diseases: teledermatology as an alternative approach in occupational screenings.

BACKGROUND: Prevention of occupational skin diseases is of high socio-economic impact. Implementing teledermatology into preventive occupational screenings holds obvious advantages; nevertheless, studies concerning this subject are scarce. OBJECTIVES: The present cross-sectional study was aimed at determining if results of a teledermatological examination are equally sensitive and specific at detecting minimal skin lesions as the conventional face-to-face examination. METHODS: The skin condition of the hands of 100 male wet workers was assessed in a face-to-face examination and a tele-examination by means of a score for minimal skin lesions. RESULTS: The comparison of the total score values that each participant received in face-to-face examination with those obtained in tele-examination proved the skin condition to be estimated significantly worse when seen in tele-examination (P < 0.0001). The median values of the sum totals and the median values for secondary lesions were higher in the tele-examination than in the face-to-face examination. CONCLUSIONS: Our findings show a tendency in tele-examination to assess the skin condition more critically in comparison with face-to-face examination. The teledermatological examination is sufficiently sensitive in detecting early signs of hand eczema, whereas signs for chronicity may get overestimated.

Case-based e-learning in occupational medicine--The NetWoRM Project in Germany.

The aim of the NetWoRM Project is the development, evaluation and implementation of a case-based e-learning tool for occupational medicine to increase the knowledge in clinical aspects of occupational medicine. To date, 19 e-learning cases have been developed. Cases were validated by 2 experts and user evaluated. Results of the user evaluation at 3 German Medical Schools are presented. Of 557 medical students registered for the online course 377 answered the online evaluation form (68%). Depending on the case, the median time spent on a case ranged from 25-43 minutes. Students enjoyed working with the cases and asked to replace more seminars by case-based e-learning. The level of knowledge required to work on the cases was rated high. This was supported by the fact that on median only 47-71% of the questions were answered correctly. Cases focusing on occupational health problems such as needle stick injuries were rated highest with respect to fun, importance for future career and the overall score. Students enjoy working on e-learning cases as an add-on to traditional teaching. Because of the high international interest the NetWoRM project is currently shared on an international base.

IL-4 supports the generation of a dendritic cell subset from murine bone marrow with altered endocytosis capacity.

Dendritic cells (DC) of myeloid origin can be generated from mouse bone marrow (BM) using granulocyte macrophage-colony stimulating factor (GM-CSF). Immature major histocompatibility complex (MHC) II(low) DC are known to bear a high endocytosis capacity, in contrast to DC precursors and mature DC. Now we found that a subset of MHC II(low) DC in BM-DC cultures is unable to exert mannose receptor-mediated endocytosis of fluorescein isothiocyanate (FITC)-dextran (DX) and resembles immature Langerhans cells (LC). The FITC-DX endocytosis activity of LC-like cells occurs at an earlier stage of development, where the surface MHC II expression is absent or very weak. This LC-like subset expresses higher levels of E-cadherin but lower amounts of the markers Gr-1, scavenger receptor 2F8, and CD11b, when compared with the highly endocytic DC subset. The latter myeloid DC resemble monocyte-derived DC (MoDC). The sorted LC-like population develops completely and exclusively into mature MHC IIhigh DC, and the MoDC-like cells remain immature MHC II(low) DC or develop into adherent MHC IIneg macrophages or mature into MHC IIhigh DC. The development of LC-like cells is promoted by interleukin-4. Thus, we show here that the simultaneous development of LC-like and MoDC-like DC subsets occurs in standard bulk cultures with GM-CSF, suggesting the existence of two different precursors for LC and MoDC in BM.

Interleukin-3Ralpha+ myeloid dendritic cells and mast cells develop simultaneously from different bone marrow precursors in cultures with interleukin-3.

The distinct developmental routes of dendritic cells and mast cells from murine bone marrow cultures with interleukin-3 are unclear. We found that short-term bone marrow cultures with interleukin-3 after 8-10 d consist of about 10%-30% dendritic cells and 70%-90% mast cell precursors, and only after 4-6 wk do homogeneous populations of mast cells emerge. Phenotypical and functional analysis of interleukin-3/dendritic cells revealed a high similarity with myeloid dendritic cells generated with granulocyte-macrophage colony stimulating factor in the expression of myeloid dendritic cell markers (CD11c+ B220- CD8alpha- CD11b+), major histocompatibility complex II and costimulatory molecules, endocytosis, maturation potential, interleukin-12 production, and T cell priming. Interleukin-3/dendritic cells expressed higher levels of interleukin-3 receptor, however. To dissect the interleukin-3/dendritic cell and mast cell development, we sorted fresh bone marrow cells into six subsets by the antibodies ER-MP12 (CD31) and ER-MP20 (Ly-6C). Both interelukin-3/dendritic cells and granulocyte-macrophage colony stimulating factor/dendritic cells develop from the same bone marrow populations, including the ER-MP12neg, ER-MP20high bone marrow monocytes. In contrast, mast cells only developed from ER-MP12(int+high), ER-MP20neg bone marrow cell subsets, indicating that different precursors exist for interleukin-3/dendritic cells and mast cells. Established mast cell cultures could not be converted to dendritic cells or stimulated to express major histocompatibility complex II molecules in vitro or home to lymph node T cell areas in vivo. In summary, we show that dendritic cells generated from bone marrow precursors with interleukin-3 are clearly myeloid and develop via a different pathway compared to bone marrow mast cells.