A cross-sectional study of sensory-motor neuropsychological function among sewage plant and sewage net workers exposed to hydrogen sulphide when handling wastewater.

OBJECTIVES: Workers at sewage treatment plants are exposed to a complex mixture of toxins, including hydrogen sulphide (H2S). An issue of concern among sewage workers, is possible negative nervous system effects from low-level H2S exposure. Empirical neuropsychological evidence indicates both that low-dose exposure to H2S exposure affects the nervous system, and the contrary, that such exposure may facilitate nervous system function, since H2S is an endogenously produced central nervous system (CNS) gasotransmitter. The aim of this study is to describe a possible association between the H2S component of the total exposure and long-term effects on neuropsychological motor function among wastewater workers. METHODS: Workers (N = 138) treating wastewater in 6 sewage-treatment plants, or in the sewer net system participated in a cross-sectional study. H2S exposure was expressed in a dichotomous exposure variable defining currently H2S-exposed (N = 112) and unexposed referent workers (N = 26), and a variable defining a job-exposure matrix for long-term total typical workplace H2S exposure. The participants went through neuropsychological tests for hand coordination, reaction time (SRT), and balance, and completed questionnaires. Pearson chi-square test or independent samples t-test was used when comparing the currently H2S-exposed workers with the unexposed control group. Multiple linear regression was used to assess associations between the independent variables age, smoking and exposure variables, and the neuropsychological tests. RESULTS: The analyses indicate increased SRT in the currently H2S-exposed group compared to controls (mean [SD] = 225.8 [29.9] versus 210.7 [26.3] ms, P = 0.019), and an association between increased SRT and current H2S-exposure in the total study sample (ß = 14.7, P = 0.026, R2 = 0.06, P = 0.050). Blindfolded balance testing indicates a nonsignificant trend in the total study sample, of reduced balance in the highest versus lowest H2S total long-term exposure-index group (Sway area [mean {SD}, mm2: 702 [410] versus 581 [278]), and a significant association between total long-term H2S exposure and reduced balance among smokers (Sway area, mm2 [ß = 38.7, P = 0.039], mean sway, mm [ß = 0.3, P = 0.015]). CONCLUSION: The observed trends and associations may be due to exposure peaks in certain work operations and pinpoint the importance of minimizing and avoiding exposure peaks, also when H2S time-weighted average measurements do not exceed an occupational exposure limit of 5 ppm.

Detailed Multiplex Analysis of SARS-CoV-2 Specific Antibodies in COVID-19 Disease.

A detailed understanding of the antibody response against SARS-CoV-2 is of high importance, especially with the emergence of novel vaccines. A multiplex-based assay, analyzing IgG, IgM, and IgA antibodies against the receptor binding domain (RBD), spike 1 (S1), and nucleocapsid proteins of the SARS-CoV-2 virus was set up. The multiplex-based analysis was calibrated against the Elecsys® Anti-SARS-CoV-2 assay on a Roche Cobas® instrument, using positive and negative samples. The calibration of the multiplex based assay yielded a sensitivity of 100% and a specificity of 97.7%. SARS-CoV-2 specific antibody levels were analyzed by multiplex in 251 samples from 221 patients. A significant increase in all antibody types (IgM, IgG, and IgA) against RBD was observed between the first and the third weeks of disease. Additionally, the S1 IgG antibody response increased significantly between weeks 1, 2, and 3 of disease. Class switching appeared to occur earlier for IgA than for IgG. Patients requiring hospital admission and intensive care had higher levels of SARS-CoV-2 specific IgA levels than outpatients. These findings describe the initial antibody response during the first weeks of disease and demonstrate the importance of analyzing different antibody isotypes against multiple antigens and include IgA when examining the immunological response to COVID-19.

Endotoxin and Hydrogen Sulphide Exposure and Effects on the Airways Among Waste Water Workers in Sewage Treatment Plants and Sewer Net System.

BACKGROUND: The purpose of this study is to investigate whether airborne exposure to endotoxins, hydrogen sulphide (H2S), and inhalable particles negatively impacts the respiratory system and inflammatory blood proteins in sewage plant and sewer net system workers and, further, to determine dose-response associations between exposure and health outcomes. METHODS: In total, 148 waste water workers (WWWs) from urban and rural sewage plants and the sewer net system participated. One hundred and twenty-one workers were exposed to sewage, 46 from sewage plants and 75 from the sewer net system. Twenty-seven workers were characterized as little or not exposed and served as an internal reference group. Personal inhalable samples were analysed for endotoxins (Limulus assay), particle dust (gravimetrically) and Salmonella and Yersinia spp. (polymerase chain reaction method, PCR). Levels of H2S were measured using personal electro chemical sensors. Intercellular adhesion molecule 1 (ICAM-1), interleukin 8 (IL-8), surfactant protein D (SP-D), club cell protein 16 (CC16), and macrophage inflammatory protein (MIP) were determined by enzyme-linked immunosorbent assay and C-reactive protein (CRP) by an HS-MicroCRP assay in blood samples. RESULTS: Workers in sewage plants were exposed to significantly higher levels of endotoxins compared to workers in the sewer net system [median 55 EU m-3 (4-262 EU m-3) and median 27 EU m-3 (1-304 EU m-3), respectively]. The estimated H2S index showed higher values when working in the sewer net system [median 3.1 (0.5-78.1)] compared to workers at the sewage plants [median 1.3 (0.5-9.3)], and the most excessive exposure was collecting sewage from cesspools (273 p.p.m.). No viable airborne Salmonella and Yersinia spp. were detected. The exposed workers had significantly higher CRP compared to the referents [1.2 µg ml-1 (0.1-19.0 µg ml-1) and 0.8 µg ml-1 (0.1-5.0 µg ml-1), respectively] and lower forced expiratory volume in 1 s (FEV1)% [92.6%, standard deviation (SD) 14.6 and 102.0%, SD 10.1, respectively], with numbers given as mean and SD. The serum concentration of CRP was significantly and negatively associated with FEV1% (ß = -7.7, R2 = 0.05) and forced vital capacity % (ß = -8.5, R2 = 0.08), and the serum concentration of ICAM-1 with the estimated exposure to H2S (ß = -19.9, R2 = 0.07). CONCLUSION: Despite moderate levels of endotoxin and H2S exposure, the results indicate an impact of these agents on lung function and the adhesion molecule ICAM-1, and a low-grade systemic inflammation was indicated in increased levels of CRP.

Inflammation in the pleural cavity following injection of multi-walled carbon nanotubes is dependent on their characteristics and the presence of IL-1 genes.

Upon inhalation, multi-walled carbon nanotubes (MWCNTs) may reach the subpleura and pleural spaces, and induce pleural inflammation and/or mesothelioma in humans. However, the mechanisms of MWCNT-induced pathology after direct intrapleural injections are still only partly elucidated. In particular, a role of the proinflammatory interleukin-1 (IL-1) cytokines in pleural inflammation has so far not been published. We examined the MWCNT-induced pleural inflammation, gene expression abnormalities, and the modifying role of IL-1α and ß cytokines following intrapleural injection of two types of MWCNTs (CNT-1 and CNT-2) compared with crocidolite asbestos in IL-1 wild-type (WT) and IL-1α/ß KO (IL1-KO) mice. Histopathological examination of the pleura 28 days post-exposure revealed mesothelial cell hyperplasia, leukocyte infiltration, and fibrosis occurring in the CNT-1 (Mitsui-7)-exposed group. The pleura of these mice also showed the greatest changes in mRNA and miRNA expression levels, closely followed by CNT-2. In addition, the CNT-1-exposed group also presented the greatest infiltrations of leukocytes and proliferation of fibrous tissue. WT mice were more prone to development of sustained inflammation and fibrosis than IL1-KO mice. Prominent differences in genetic and epigenetic changes were also observed between the two genotypes. In conclusion, the fibrotic response to MWCNTs in the pleura depends on the particles' physico-chemical properties and on the presence or absence of the IL-1 genes. Furthermore, we found that CNT-1 was the most potent inducer of inflammatory responses, followed by CNT-2 and crocidolite asbestos.

Physical activity initiated by employer induces improvements in a novel set of biomarkers of inflammation: an 8-week follow-up study.

PURPOSE: We investigated the level of pro- and anti-inflammatory biomarkers before and after 8 weeks of unsupervised physical activity (PA) initiated by employer. METHODS: During autumn 2014, background data, blood samples and self-reported exercise level were collected from 76 men and 41 women in a Norwegian road maintenance company. Monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), leptin, adiponectin, p-selectin and CD40 ligand (CD40L) were analyzed. [Formula: see text] was measured in a subgroup of 50 subjects. RESULTS: With reference point of exercise ≤1 time/week, we found that participants who exercised 2-3 times/week had higher [Formula: see text] values (5.6 mL kg-1 min-1; 95% CI [1.3, 9.9]). MCP-1 was lower in those who exercised ≥ 4 times/week (-81.98 pg/ml [-142.9, -21.0]). IL-6 and p-selectin levels were lower in females who exercised ≥4 times/week (-1.04 pg/ml [-2.04, -0.03] and -13.75 ng/ml [-24.03, -3.48]). Leptin was lower in participants who exercised 2-3 times/week (-0.39 µg/ml ln [-0.68, -0.09]) and ≥4 times/week (-0.69 µg/ml ln [-1.10, -0.28]). During follow-up, [Formula: see text] increased (2.9 mL kg-1 min-1 [1.5, 4.3]), while p-selectin and CD40L decreased (-2.33 ng/ml [-3.78, -0.87] and 718.14 ng/ml [-1368, -68]). MCP-1 levels decreased among men (-32.70 pg/ml [-51.21, -14.19]). A joint analysis of all biomarkers (inversed adiponectin) showed that those who exercised ≥4 times/week at baseline had lower total levels of biomarkers and that total biomarker levels decreased during follow-up. CONCLUSIONS: Exercising several times a week was associated with less inflammation compared to exercising once a week or less. During the 8-week follow-up, total levels of biomarkers of inflammation improved.