[Health protection and climate change require ambitious limit values for air pollutants in Europe : Opinion on the revision of the Directive on Air Quality and Clean Air for Europe of the Environmental Public Health commission of the Robert Koch Institute and the Federal Environment Agency]

Based on scientific findings, the World Health Organization (WHO) has recommended stricter guideline values for air quality in 2021. Significant reductions in the annual mean values of particulate matter (particle size 2.5 µm or smaller, PM2.5) and long-term exposure to nitrogen dioxide (NO2) and ozone (O3) were put forward. The risk of mortality already increases above the WHO guideline values, as shown in studies investigating low concentrations of air pollutants. In Germany, the 2021 WHO guideline values for PM2.5 and NO2 were clearly exceeded in 2022.In this position paper we give the following recommendations for the European Air Quality Directive: (1) set binding limit values according to WHO 2021, (2) apply the limit values to the whole of Europe, (3) continue and expand the established country-based monitoring networks, (4) expand air quality measurements for ultrafine particles and soot particles, and (5) link air pollution control and climate protection measures.Stricter limits for air pollutants require societal and political changes in areas such as mobility, energy use and generation, and urban and spatial planning. Implementation according to WHO 2021 would lead to a net economic benefit of 38 billion euros per year.Ambitious limit values for air pollutants also have an impact on climate change mitigation and its health impacts. The Environmental Public Health commission concludes that more ambitious limit values are crucial to enable effective health protection in Germany and calls for air pollutant limit values in line with the 2021 WHO recommendations to become binding in Europe.

[Occupational obstructive airway diseases: How can early diagnosis be made to avoid chronic courses?]

Since abolishing the obligation to terminate the harmful professional activity from January 1st, 2021 onwards for some occupational diseases including obstructive respiratory diseases in Germany, the recognition of occupational diseases coded under 4301, 4302 and 1315 according the Occupational Diseases Ordinance has increased significantly. By the time these diseasese are recognized, they are usually already at an advanced stage. Therefore, early detection will play a greater role in the future, as the statutory accident insurance can offer individual preventive measures in order to minimize the consequences of illness and thus also the socio-economic burden. However, precursors of such obstructive airway diseases are often overlooked. For optimizing early detection, the statutory accident insurance worked out an early notification procedure for the respiratory tract - comparable to the already well-established dermatological procedure. "Early cases" from the pilot regions can be reported there; to qualify for being reported as early cases, patients must persue insured professional activity with potential effects on the respiratory tract and suffer from a disease of the upper or lower respiratory tract according to the ICD-10 code (e.g. J31.0 chronic rhinitis).

Intestinal epithelial barrier integrity investigated by label-free techniques in ulcerative colitis patients

The intestinal epithelial barrier, among other compartments such as the mucosal immune system, contributes to the maintenance of intestinal homeostasis. Therefore, any disturbance within the epithelial layer could lead to intestinal permeability and promote mucosal inflammation. Considering that disintegration of the intestinal epithelial barrier is a key element in the etiology of ulcerative colitis, further assessment of barrier integrity could contribute to a better understanding of the role of epithelial barrier defects in ulcerative colitis (UC), one major form of chronic inflammatory bowel disease. Herein, we employ fast, non-destructive, and label-free non-linear methods, namely coherent anti-Stokes Raman scattering (CARS), second harmonic generation (SHG), two-photon excited fluorescence (TPEF), and two-photon fluorescence lifetime imaging (2P-FLIM), to assess the morpho-chemical contributions leading to the dysfunction of the epithelial barrier. For the first time, the formation of epithelial barrier gaps was directly visualized, without sophisticated data analysis procedures, by the 3D analysis of the colonic mucosa from severely inflamed UC patients. The results were compared with histopathological and immunofluorescence images and validated using transmission electron microscopy (TEM) to indicate structural alterations of the apical junction complex as the underlying cause for the formation of the epithelial barrier gaps. Our findings suggest the potential advantage of non-linear multimodal imaging is to give precise, detailed, and direct visualization of the epithelial barrier in the gastrointestinal tract, which can be combined with a fiber probe for future endomicroscopy measurements during real-time in vivo imaging.

Label-free multimodal imaging of infected Galleria mellonella larvae

Non-linear imaging modalities have enabled us to obtain unique morpho-chemical insights into the tissue architecture of various biological model organisms in a label-free manner. However, these imaging techniques have so far not been applied to analyze the Galleria mellonella infection model. This study utilizes for the first time the strength of multimodal imaging techniques to explore infection-related changes in the Galleria mellonella larvae due to massive E. faecalis bacterial infection. Multimodal imaging techniques such as fluorescent lifetime imaging (FLIM), coherent anti-Stokes Raman scattering (CARS), two-photon excited fluorescence (TPEF), and second harmonic generation (SHG) were implemented in conjunction with histological HE images to analyze infection-associated tissue damage. The changes in the larvae in response to the infection, such as melanization, vacuolization, nodule formation, and hemocyte infiltration as a defense mechanism of insects against microbial pathogens, were visualized after Enterococcus faecalis was administered. Furthermore, multimodal imaging served for the analysis of implant-associated biofilm infections by visualizing biofilm adherence on medical stainless steel and ePTFE implants within the larvae. Our results suggest that infection-related changes as well as the integrity of the tissue of G. mellonella larvae can be studied with high morphological and chemical contrast in a label-free manner.

Revealing the Chemical Composition of Birch Pollen Grains by Raman Spectroscopic Imaging

The investigation of the biochemical composition of pollen grains is of the utmost interest for several environmental aspects, such as their allergenic potential and their changes in growth conditions due to climatic factors. In order to fully understand the composition of pollen grains, not only is an in-depth analysis of their molecular components necessary but also spatial information of, e.g., the thickness of the outer shell, should be recorded. However, there is a lack of studies using molecular imaging methods for a spatially resolved biochemical composition on a single-grain level. In this study, Raman spectroscopy was implemented as an analytical tool to investigate birch pollen by imaging single pollen grains and analyzing their spectral profiles. The imaging modality allowed us to reveal the layered structure of pollen grains based on the biochemical information of the recorded Raman spectra. Seven different birch pollen species collected at two different locations in Germany were investigated and compared. Using chemometric algorithms such as hierarchical cluster analysis and multiple-curve resolution, several components of the grain wall, such as sporopollenin, as well as the inner core presenting high starch concentrations, were identified and quantified. Differences in the concentrations of, e.g., sporopollenin, lipids and proteins in the pollen species at the two different collection sites were found, and are discussed in connection with germination and other growth processes.

Outdoor air pollution from industrial chemicals causing new onset of asthma or COPD: a systematic review protocol

Background

Until today, industrial sources contribute to the multifaceted contamination of environmental air. Exposure to air pollutants has the potential to initiate and promote asthma and chronic obstructive pulmonary disease (COPD). At global scale, both entities cause the majority of about 4 million annual deaths by respiratory disease. However, we identified industrial contamination as a subgroup of air pollution that may be associated with this burden and is underinvestigated in research. Therefore, the aim of this study is to investigate associations between substances industrially released into environmental air and the occurrence of asthma and COPD in the human population. Here we present the protocol for our systematic review of the current evidence.

Methods

The following determinations will be applied during the systematic review process and are specified in the protocol that complies with the PRISMA-P statement. Populations of children and adults, as well as outdoor workers, exposed to industrially released air pollutants are of interest. Eligible studies may include subjects as controls who are non- or less exposed to the investigated air pollutants. The outcomes new-onset asthma and/or COPD investigated with risk ratio, odds ratio, hazard ratio, incidence rate ratio, cumulative incidence, and incidence rate are eligible. We will search the electronic literature databases EMBASE, MEDLINE, and Web of Science for peer-reviewed reports of incidence studies and incidence case-control studies. After systematic sorting of initial records, included studies will be subjected to quality assessment. Data will be synthesized qualitatively and, if appropriate, quantitatively for risk ratio and odds ratio. We will maintain and provide a PRISMA report.

Discussion

Results of this systematic review may indicate alterations of incidence and risk of asthma and/or COPD in populations within industrial exposure radiuses including outdoor workplaces. Specific causal substances and compositions will be identified, but results will depend on the exposure assessment of the eligible studies. Our approach covers effects of industrial contributions to overall air pollution if studies reportedly attribute investigated emissions to industry. Results of this study may raise the question wether the available higher-level evidence sufficiently covers the current scale of industrial exposure scenarios and their potential harm to respiratory health.

Trial registration

This protocol was registered in PROSPERO, registration number CRD42020151573.

Seroprevalence of Chlamydophila Psittaci among Employees of Two German Duck Farms

Psittacosis is a zoonotic infectious disease that is caused by Chlamydophila psittaci. To determine the occupational risk of getting the infection, we investigated the seroprevalence of C. psittaci among employees of two German duck farms and two slaughterhouses according to their level of exposure to the pathogen during the years 2010, 2007, and 2004. In summary, we found low seroprevalence (≈ 8%) throughout the study population almost irrespective of the duty of a given worker. Surprisingly, in 2010, the anti-C. psittaci-specific antibody prevalence in the group of slaughterer (38.9%) was significantly increased in comparison to the non-exposed employees (p = 0.00578). This indicates that individuals in the surrounding of slaughterhouses exposed especially to aerosols containing C. psittaci elementary bodies bear a greater occupational risk of getting infected.

Seroprevalence of Campylobacter-Specific Antibodies in two German Duck Farms - A Prospective Follow-Up Study

Several studies have shown that about 60-100% of farmed ducks are colonized by Campylobacter species. Because of this, a higher risk of campylobacteriosis among duck farm workers can be assumed. To estimate the risk of Campylobacter infections in duck farm workers, we investigated the prevalence of Campylobacter spp. in ducks of two duck farms and the seroprevalence of anti-Campylobacter antibodies (IgA and IgG) in two cohorts of workers. The first cohort consisted of high-exposed stable workers and slaughterers, which was compared to a second cohort of non-/low-exposed persons. Duck caecal swabs and serum samples were collected in 2004, 2007, and 2010. The colonization rate in the examined ducks was found to be 80-90%. The seroprevalence of anti-Campylobacter IgA and IgG antibodies among the non-exposed cohort was found to be 0.00% in all 3 years. In contrast, the exposed cohort demonstrated an IgA seroprevalence of 4.17% in 2004, 5.71% in 2007, and 0.00% in 2010 and an IgG seroprevalence of 8.33% in 2004, 0.00% in 2007, and 4.29% in 2010. In conclusion, in 2004, we observed a significantly higher anti-Campylobacter antibody seroprevalence in the exposed cohort followed by a steady reduction in 2007 and 2010 under occupational health and safety measures.

Cytotoxicity of carbon nanohorns in different human cells of the respiratory system

One of the new synthetic carbon-based nanomaterials is carbon nanohorns (CNH). A potential risk for employees of production processes is an unintentional intake of these nanomaterials via inhalation. Once taken up, nanoparticles might interact with cells of different tissues as well as with intercellular substances. These interactions may have far-reaching consequences for human health. Currently, many gaps in available information on the CNH toxicological profile remain. The aim of this study was to determine the cytotoxicity of CNH particles on human epithelial cells of the respiratory system with special consideration given to different particle sizes. In all cell lines, cell viability was reduced after 24 h of exposure up to 60% and metabolic activity as evidenced by mitochondrial activity was lowered to 9% at a concentration of 1 g/L. The three respiratory cell lines differed in their sensitivity. The most robust cells were the bronchial epithelial cells. Further, particle size fractions induced different adverse effect strength, whereby no correlation between particle size fraction and toxicity was found. These findings demonstrate the need for further information regarding the behavior and effect strength of nanomaterial. To avoid the production of new harmful materials, a more comprehensive integration of results from toxicity studies in the development processes of engineered nanomaterials is recommended not only from an occupational viewpoint but also from an environmental perspective.

Use of density centrifugation for delayed cryopreservation of stallion sperm: perform sperm selection directly after collection or after storage?

Equipment for cryopreservation of stallion sperm is not always available. In such cases, diluted semen can be shipped to a facility for later cryopreservation. The aim of this study was to evaluate if selection of sperm via density centrifugation yields higher survival rates when cryopreservation is to be delayed (i.e. carried out after 1 day of storage at 5°C). Two-layer iodixanol as well as single-layer Androcoll density centrifugation were tested and compared with samples prepared with standard centrifugation. Special emphasis was placed on comparing centrifugation on the day of semen collection with centrifugation after 1-day refrigerated storage. Sperm morphology and motility as well as membrane and chromatin integrity were evaluated before and after centrifugation. Sperm motility and membrane integrity were also assessed after cryopreservation. It was found that both two- and single-layer density centrifugation processing resulted in higher percentages of morphologically normal and motile sperm with higher membrane and chromatin integrity, as compared to standard centrifugation or diluted samples. Differences were only in the order of magnitude of 5%. Recovery rates after density centrifugation were only approximately 30-40%. When cryopreservation was carried out after 1-day refrigerated storage, centrifugation processing of sperm directly after semen collection resulted in higher percentages of plasma membrane intact sperm post-thaw as compared to performing centrifugation processing of stored sperm just prior to cryopreservation. No significant differences in progressively motile sperm post-thaw were seen. Taken together, for delayed cryopreservation, it is best to perform density centrifugation directly after collection rather than immediately prior to cryopreservation.

Testing for cattle allergy: modified diagnostic cutoff levels improve sensitivity in symptomatic claw trimmers

Background

The diagnosis of cattle-related sensitization is complicated by the variability and complexity of cattle allergen extracts.

Objective

To evaluate a modified diagnostic procedure leading to more accurate results especially in the early phase of sensitization.

Methods

We tested 27 claw trimmers with and 65 without cattle-related symptoms using two commercially available cattle allergen extracts. We also used a self-prepared cattle allergen mix designed to represent the full spectrum of cattle allergens from a typical agricultural workplace.

Results

More than 50% of symptomatic claw trimmers showed negative test results with commercial extracts and a sensitization cutoff point of 0.35 kU/l. In contrast, with the self-prepared cattle allergen mix, positive results were observed for almost all of them. Evaluating the results of the commercial test kits at different cutoff levels, we found an ideal cutoff point to improve the sensitivity at 0.2 kU/l.

Conclusion

Additional tests with self-made cattle hair extracts can help to bridge the diagnostic gap seen in patients showing cattle-related symptoms, but negative results in commercially available tests. For early-stage sensitization screening, we propose to lower the cutoff level indicating sensitization to 0.2 kU/l.

Volatile organic compounds in dwelling houses and stables of dairy and cattle farms in Northern Germany

Farmers are exposed to a complex mixture of airborne substances which can represent a health hazard. Especially animal production on a farm can be a risk factor for respiratory diseases. Most studies in this context focused on bioaerosols, compounds attached to bioaerosols or on gases such as ammonia or hydrogen sulfide. Less attention was paid to volatile organic compounds (VOCs) which may also cause respiratory diseases. This pilot study presents results of measuring VOCs in the air of the dwellings and stables, as well as in the outdoor environment, of cattle farms in Northern Germany in spring and autumn. Farmers on all selected farms complained of symptoms such as asthma, rhinitis and conjunctivitis which occurred especially during work in the stable but also in the dwellings. The mean concentration of total VOC (TVOC) for the outdoor environment, the dwellings, and the stables were 100 microg m(-3), 763 microg m(-3), 322 microg m(-3) in spring and 143 microg m(-3), 544 microg m(-3), 595 microg m(-3) in autumn, respectively. There was no significant difference in season. TVOC concentrations in dwellings on farms were elevated when compared to dwellings in other environments, probably because of an additional exposure to fuels and chemicals used in agriculture. Aliphatic and alicyclic hydrocarbons, aromatic compounds, and terpenes were main compounds of the dwellings and ketones, alcohols, and esters of the stables. Terpene concentrations in the stables were low probably because straw, which was not a strong terpene emitter, was used instead of sawdust as floor covering. Large amounts of methylethylketone were encountered in the air of one stable, probably from animal exhalation caused by increased animal activity. However, it was unlikely that this caused respiratory symptoms. Generally it was likely that the concentrations of VOCs were too low to have health effects on their own. On the other hand, the VOC concentrations were in a multifactor concentration range in which health effects could occur depending on the interaction with other exposure factors. Fungal spores and bacteria were observed in addition to VOCs at the examined locations. Therefore it is possible that the observed VOCs played a role in exacerbating respiratory symptoms in this multifactor exposure.