Effects after inhalation of (1-->3)-beta-D-glucan in healthy humans

Derivation of an occupational exposure limit for β-glucans

β-Glucans are abundant bacterial, yeast, and fungal cell wall polysaccharides that have been shown to activate the immune system. Establishment of an occupational exposure limit (OEL) for β-glucan exposure is critical to the protection of worker health, as these exposures have been linked to immunosuppressive and inflammatory reactions and possibly the development of respiratory diseases. Detectable concentrations of β-glucans have been identified in common occupational inhalation exposure scenarios, such as in the agricultural and waste management sectors. However, no published exposure benchmarks for inhalation of β-glucans are available for workers or the general population. Thus, a health-based OEL for inhalation exposure of workers to β-glucans was derived based on consideration of human and non-human effect data for this class of compounds and contemporary risk assessment methods. The weight of the evidence indicated that the available data in humans showed significant methodological limitations, such as lack of a representative study size, appropriate control population, and clear dose-response relationship. Thus, an OEL of 150 ng/m³ was derived for β-glucans based on the most relevant nonclinical study. This OEL provides an input to the occupational risk assessment process, allows for comparisons to worker exposure, and can guide risk management and exposure control decisions.

Nasal lavage as analytical tool in assessment of exposure to particulate and microbial aerosols in wood pellet production facilities

Occupational exposure to wood dust and bioaerosols may lead to numerous respiratory tract diseases. We aimed to assess a degree of workplace contamination with dust, bacteria, fungi, endotoxins, and (1 → 3)-β-D-glucans released into the air during wood processing in pellet production facilities and to check against this background the usefulness of nasal lavage (NAL) as analytical tool for assessment of combined workers' exposure to airborne dust and microbiological contaminants. In 10 pellet plants, the particulate (wood dust) aerosol concentrations were determined by using Grimm aerosol spectrometer and CIS filter sampler. The collected CIS samples were subsequently used to evaluate endotoxin and (1 → 3)-β-D-glucan concentrations. Simultaneously with particulate aerosol, bioaerosol samples were collected by using 6-stage Andersen and single-stage MAS impactors. Bacterial and fungal aerosol concentrations were calculated and all isolated microorganisms were taxonomically identified. NAL fluid samples were collected from workers exposed to studied aerosols and the concentrations of proinflammatory mediators (IL-1β, IL-6, IL-8, and TNFα) and cytological image of nasal mucosa (expressed as cell counts) were established. The dynamics of production activities resulted in wide range of observed wood dust, microorganism, endotoxin and (1 → 3)-β-D-glucan concentrations reaching periodically extremely high values up to 65 mg m^-3, 19,320 CFU m^-3, 215 ng m^-3 and 1525 ng m^-3, respectively. Environmental stress caused by exposure to particulate and microbial aerosols stimulated immune response among workers of pellet production facilities. Correlation analysis revealed that interleukin levels and the number of cells in NAL were significantly affected by both wood dust and bioaerosol concentrations. As nasal mucosa serves as the primary barrier against inhaled pollutants, NAL seems a reliable analytical material to assess work-related adverse respiratory health outcomes derived from such exposure.

Inhalable dust, endotoxins and (1-3)-β-d-glucans as indicators of exposure in waste sorting plant environment

The aim of the study was to assess the levels of inhalable dust, endotoxins and (1-3)-β-d-glucans as agents harmful to the respiratory tract of workers of municipal waste sorting plants and interaction between these agents based on the measurements taken in two plants with different processing capacities. The study was conducted in summer season in two waste sorting plants (WSPs) differing in processing capacity. Samples of bioaerosol for inhalable dust (gravimetric method), endotoxins (LAL test in kinetic, chromogenic version) and (1-3)-β-d-glucans (Glucatell test in kinetic version) were collected from 42 sorting workers using individual aspirators with glass fiber filters during the work shift. Average geometric concentrations (geometric standard deviation; min-max) of inhalable dust, endotoxins and (1-3)-β-d-glucans were: WSP1: 1.7 mg m^-3 (2.2; 0.6-6.9 mg m^-3); 15.9 ng m^-3 (2.1; 5.4-78.9 ng m^-3), 55.1 ng m^-3 (1.8; 20.7-188.6 ng m^-3) and WSP2: 0.8 mg m^-3 (2.2; 0.2-3.8 mg m^-3), 9.8 ng m^-3 (2.4; 1.6-29.7 ng m^-3), 45.0 ng m^-3 (3.2, 5.7-212.9 ng m^-3), respectively. A significantly higher concentration of inhalable dust was recorded in WSP1 with bigger processing capacity compared to WSP2 (less processing capacity). Significant (p < 0.05) and very high correlations (Spearman rank R > 0.7) were found between the concentrations of all analyzed harmful agents. Processing capacity of waste sorting plants differentially affects the concentrations of inhalable dust, whereas concentrations of endotoxins and glucans are less clearly affected. This suggests that relative concentrations of endotoxin and glucan are depending on the waste sorting capacity.

β-Glucans in standardized allergen extracts

Background: Allergen extracts contain variable quantities of bacterial endotoxin. Recent studies have suggested that (1→3)-β-D-glucans (β-glucans), also microbial cell wall components, may have adjuvant properties that could affect allergen immunotherapy.

Objective: To determine the quantities of β-glucans in standardized allergen extracts.

Materials and Methods : Ninety-four lots of 13 standardized allergen extracts were tested for β-glucan content by Glucatell assay, and for endotoxin content by a specific, chromogenic formulation of the Limulus amebocyte lysate test.

Results: Standardized allergen extracts contain variable quantities of endotoxins and β-glucans. As in our previous work, endotoxin activity was greatest in cat pelt and Dermatophagoides farinae, and least in the pollens. There was no correlation between endotoxin and β-glucan levels ( r = 0.1887; P = 0.07). β-Glucan content was highest for grass pollen (median content, 10.6 ng/ml; range, 0.4—41.8 ng/ml), ragweed pollen (32.9 ng/ml; range, 6.5—41.2 ng/ml), and cat pelt (25.5 ng/ml; range, 16.7—41.1 ng/ml), and lowest for cat hair (4.9 ng/ml; range, 1.2—10.3 ng/ml), D. farinae (1.2 ng/ml; range, 0.4—5.2 ng/ml) and Dermatophagoides pteronyssinus (1.8 ng/ml; range, 0.4—6.7 ng/ml).

Conclusions: β-Glucans are present in standardized allergen extracts. The effects of these quantities of β-glucans on allergen immunotherapy and allergen skin testing require further study.

Urban Enhancement of PM10 Bioaerosol Tracers Relative to Background Locations in the Midwestern United States

Bioaerosols are well-known immune-active particles that exacerbate respiratory diseases. Human exposures to bioaerosols and their resultant health impacts depend on their ambient concentrations, seasonal and spatial variation, and co-pollutants, which are not yet widely characterized. In this study, chemical and biological tracers of bioaerosols were quantified in respirable particulate matter (PM10) collected at three urban and three background sites in the Midwestern United States across four seasons in 2012. Endotoxins from gram negative bacteria (and a few gram positive bacteria), water-soluble proteins, and tracers for fungal spores (fungal glucans, arabitol and mannitol) were ubiquitous and showed significant seasonal variation and dependence on temperature. Fungal spores were elevated in spring and peaked in summer, following the seasonal growing cycle, while endotoxins peaked in autumn during the row crop harvesting season. Paired comparisons of bioaerosols in urban and background sites revealed significant urban enhancements in PM10, fungal glucans, endotoxins and water-soluble proteins relative to background locations, such that urban populations have a greater outdoor exposure to bioaerosols. These bioaerosols contribute, in part, to the urban excesses in PM10. Higher bioaerosol mass fractions in urban areas relative to background sites indicate that urban areas serve as a source of bioaerosols. Similar urban enhancements in water-soluble calcium and its correlation with bioaerosol tracers point towards wind-blown soil as an important source of bioaerosols in urban areas.

Urban Enhancement of PM10 Bioaerosol Tracers Relative to Background Locations in the Midwestern United States

Bioaerosols are well-known immune-active particles that exacerbate respiratory diseases. Human exposures to bioaerosols and their resultant health impacts depend on their ambient concentrations, seasonal and spatial variation, and co-pollutants, which are not yet widely characterized. In this study, chemical and biological tracers of bioaerosols were quantified in respirable particulate matter (PM₁₀) collected at three urban and three background sites in the Midwestern United States across four seasons in 2012. Endotoxins from gram negative bacteria (and a few gram positive bacteria), water-soluble proteins, and tracers for fungal spores (fungal glucans, arabitol and mannitol) were ubiquitous and showed significant seasonal variation and dependence on temperature. Fungal spores were elevated in spring and peaked in summer, following the seasonal growing cycle, while endotoxins peaked in autumn during the row crop harvesting season. Paired comparisons of bioaerosols in urban and background sites revealed significant urban enhancements in PM₁₀, fungal glucans, endotoxins and water-soluble proteins relative to background locations, such that urban populations have a greater outdoor exposure to bioaerosols. These bioaerosols contribute, in part, to the urban excesses in PM₁₀. Higher bioaerosol mass fractions in urban areas relative to background sites indicate that urban areas serve as a source of bioaerosols. Similar urban enhancements in water-soluble calcium and its correlation with bioaerosol tracers point towards wind-blown soil as an important source of bioaerosols in urban areas.

Microbial Ligand Costimulation Drives Neutrophilic Steroid-Refractory Asthma

Asthma is a heterogeneous disease whose etiology is poorly understood but is likely to involve innate responses to inhaled microbial components that are found in allergens. The influence of these components on pulmonary inflammation has been largely studied in the context of individual agonists, despite knowledge that they can have synergistic effects when used in combination. Here we have explored the effects of LPS and β-glucan, two commonly-encountered microbial agonists, on the pathogenesis of allergic and non-allergic respiratory responses to house dust mite allergen. Notably, sensitization with these microbial components in combination acted synergistically to promote robust neutrophilic inflammation, which involved both Dectin-1 and TLR-4. This pulmonary neutrophilic inflammation was corticosteroid-refractory, resembling that found in patients with severe asthma. Thus our results provide key new insights into how microbial components influence the development of respiratory pathology.

Assessment of the total inflammatory potential of bioaerosols by using a granulocyte assay

Occupational health symptoms related to bioaerosol exposure have been observed in a variety of working environments. Bioaerosols contain microorganisms and microbial components. The aim of this study was to estimate the total inflammatory potential (TIP) of bioaerosols using an in vitro assay based on granulocyte-like cells. A total of 129 bioaerosol samples were collected in the breathing zone of workers during their daily working routine at 22 biofuel plants. The samples were analyzed by traditional assays for dust, endotoxin, fungal spores, (1-->3)-beta-d-glucan, total number of bacteria, the enzyme N-acetyl-beta-d-glucosaminidase (NAGase; primarily originating from fungi), Aspergillus fumigatus, and mesophilic and thermophilic actinomycetes; the samples were also assayed for TIP. In a multilinear regression four factors were significant for the TIP values obtained: endotoxin (P < 0.0001), fungal spores (P < 0.0001), (1-->3)-beta-d-glucan (P = 0.0005), and mesophilic actinomycetes (P = 0.0063). Using this model to estimate TIP values on the basis of microbial composition, the correlation to the measured values was r = 0.91. When TIP values obtained in the granulocyte assay were related to the primary working area, we found that bioaerosol samples from personnel working in straw storage facilities showed high TIP values ( approximately 50 times the TIP of unstimulated controls). In contrast, bioaerosol samples from personnel with work functions in offices or laboratories showed low TIP values ( approximately 5 times the TIP of the unstimulated control). This indicates, as expected, that these areas were less contaminated. In conclusion, the granulocyte assay reacts to multiple contaminants in the environmental samples and can be used to obtain a measurement of TIP. Therefore, potential occupational health effects related to inflammation of the airways in a working environment can be estimated using this assay.

The biocontaminants and complexity of damp indoor spaces: more than what meets the eyes

Nine types of biocontaminants in damp indoor environments from microbial growth are discussed: (1) indicator molds; (2) Gram negative and positive bacteria; (3) microbial particulates; (4) mycotoxins; (5) volatile organic compounds, both microbial (MVOCs) and non-microbial (VOCs); (6) proteins; (7) galactomannans; (8) 1-3-β-D-glucans (glucans) and (9) lipopolysaccharides (LPS — endotoxins). When mold species exceed those outdoors contamination is deduced. Gram negative bacterial endotoxins, LPS in indoor environments, synergize with mycotoxins. The gram positive Bacillus species, Actinomycetes (Streptomyces, Nocardia and Mycobacterium), produce exotoxins. The Actinomycetes are associated with hypersensitivity pneumonitis, lung and invasive infections. Mycobacterial mycobacterium infections not from M. tuberculosis are increasing in immunocompetent individuals. In animal models, LPS enhance the toxicity of roridin A, satratoxins G and aflatoxin B1 to damage the olfactory epithelium, tract and bulbs (roridin A, satratoxin G) and liver (aflatoxin B1). Aflatoxin B1 and probably trichothecenes are transported along the olfactory tract to the temporal lobe. Co-cultured Streptomyces californicus and Stachybotrys chartarum produce a cytotoxin similar to doxorubicin and actinomycin D (chemotherapeutic agents). Trichothecenes, aflatoxins, gliotoxin and other mycotoxins are found in dust, bulk samples, air and ventilation systems of infested buildings. Macrocyclic trichothecenes are present in airborne particles <2 μm. Trichothecenes and stachylysin are present in the sera of individuals exposed to S. chartarum in contaminated indoor environments. Haemolysins are produced by S. chartarum, Memnoniella echinata and several species of Aspergillus and Penicillium. Galactomannans, glucans and LPS are upper and lower respiratory tract irritants. Gliotoxin, an immunosuppressive mycotoxin, was identified in the lung secretions and sera of cancer patients with aspergillosis produced by A. fumigatus, A. terreus, A. niger and A. flavus.

Airborne fungal and bacterial components in PM1 dust from biofuel plants

Fungi grown in pure cultures produce DNA- or RNA-containing particles smaller than spore size (<1.5 microm). High exposures to fungi and bacteria are observed at biofuel plants. Airborne cultivable bacteria are often described to be present in clusters or associated with larger particles with an aerodynamic diameter (d(ae)) of 2-8 microm. In this study, we investigate whether airborne fungal components smaller than spore size are present in bioaerosols in working areas at biofuel plants. Furthermore, we measure the exposure to bacteria and fungal components in airborne particulate matter (PM) with a D(50) of 1 microm (called PM(1) dust). PM(1) was sampled using Triplex cyclones at a working area at 14 Danish biofuel plants. Millipore cassettes were used to sample 'total dust'. The PM(1) particles (29 samples) were analysed for content of 11 different components and the total dust was analysed for cultivable fungi, N-acetyl-beta-D-glucosaminidase (NAGase), and (1 --> 3)-beta-D-glucans. In the 29 PM(1) samples, cultivable fungi were found in six samples and with a median concentration below detection level. Using microscopy, fungal spores were identified in 22 samples. The components NAGase and (1 --> 3)-beta-D-glucans, which are mainly associated with fungi, were present in all PM(1) samples. Thermophilic actinomycetes were present in 23 of the 29 PM(1) samples [average = 739 colony-forming units (CFU) m(-3)]. Cultivable and 'total bacteria' were found in average concentrations of, respectively, 249 CFU m(-3) and 1.8 x 10(5) m(-3). DNA- and RNA-containing particles of different lengths were counted by microscopy and revealed a high concentration of particles with a length of 0.5-1.5 microm and only few particles >1.5 microm. The number of cultivable fungi and beta-glucan in the total dust correlated significantly with the number of DNA/RNA-containing particles with lengths of between 1.0 and 1.5 microm, with DNA/RNA-containing particles >1.5 microm, and with other fungal components in PM(1) dust. Airborne beta-glucan and NAGase were found in PM(1) samples where no cultivable fungi were present, and beta-glucan and NAGase were found in higher concentrations per fungal spore in PM(1) dust than in total dust. This indicates that fungal particles smaller than fungal spore size are present in the air at the plants. Furthermore, many bacteria, including actinomycetes, were present in PM(1) dust. Only 0.2% of the bacteria in PM(1) dust were cultivable.

Treatment of fungal bioaerosols by a high-temperature, short-time process in a continuous-flow system

Airborne fungi, termed fungal bioaerosols, have received attention due to the association with public health problems and the effects on living organisms in nature. There are growing concerns that fungal bioaerosols are relevant to the occurrence of allergies, opportunistic diseases in hospitals, and outbreaks of plant diseases. The search for ways of preventing and curing the harmful effects of fungal bioaerosols has created a high demand for the study and development of an efficient method of controlling bioaerosols. However, almost all modern microbiological studies and theories have focused on microorganisms in liquid and solid phases. We investigated the thermal heating effects on fungal bioaerosols in a continuous-flow environment. Although the thermal heating process has long been a traditional method of controlling microorganisms, the effect of a continuous high-temperature, short-time (HTST) process on airborne microorganisms has not been quantitatively investigated in terms of various aerosol properties. Our experimental results show that the geometric mean diameter of the tested fungal bioaerosols decreased when they were exposed to increases in the surrounding temperature. The HTST process produced a significant decline in the (1-->3)-beta-d-glucan concentration of fungal bioaerosols. More than 99% of the Aspergillus versicolor and Cladosporium cladosporioides bioaerosols lost their culturability in about 0.2 s when the surrounding temperature exceeded 350 degrees C and 400 degrees C, respectively. The instantaneous exposure to high temperature significantly changed the surface morphology of the fungal bioaerosols.

Inflammatory and allergic responses to airborne office dust in five human provocation experiments

Five studies on the effects of dust have been published from The Department of Environmental and Occupational Medicine, the University of Aarhus, Denmark. These five studies support that exposures to normal office dust for up to 5 h at concentration ranges occasionally seen in non-occupational indoor environments may cause health effects which can be measured both objectively and subjectively in healthy subjects and subjects with different types of hypersensitivity. In these five studies, the lowest observed effect level was indicated to be 75 microg/m3 (total suspended particulates). However, dust from different buildings may have different toxicity and some of the five studies had higher No Observed Effect Level (NOEL) than this value. The studies give strong evidence that dust exposures cause decreased tear film stability or break-up time and increased number of eosinophil cells in nasal lavages. There is also strong evidence that general well-being decrease during exposures. This is also reflected in increasing general irritation in eyes, nose, and throat. The combined findings support the theory that the subjects' responses to indoor dust exposures are caused by sensory perceptions, weak allergic, or weak inflammatory responses at or in the exposed tissues. More than one biological mechanism may be involved at the same time or subsequently. No signs of effects in non-exposed organs or tissues were seen, not even in sensitive persons.

PRACTICAL IMPLICATIONS

The studies indicate that dust exposures indoors may explain many reported symptoms and health effects and underlines the importance of source reduction.

Development of a two-site enzyme immunoassay based on monoclonal antibodies to measure airborne exposure to (1-->3)-beta-D-glucan

(1-->3)-beta-D-glucan is found in cell walls of some fungi, bacteria and plants. It plays a crucial role in bioaerosol-induced inflammatory reactions. To estimate the level of airborne (1-->3)-beta-D-glucan exposure, a monoclonal antibody-based two-site enzyme immunoassay (mAb-EIA) was developed. The results obtained with the mAb-EIA were compared with the results of a Limulus amoebocyte lysate-based assay for (1-->3)-beta-D-glucan. Three mAbs produced by mouse immunization with bovine serum albumin-conjugated laminarin were enriched by in vitro production in a modular mini-fermenter and affinity purified. Two mAbs were selected for the development of a two-site EIA specific for (1-->3)-beta-D-glucan. Different polysaccharides, fungal and plant seed extracts, and airborne inhalable dust from workplaces (poultry farms, pig stables, grain storage houses, and a laboratory animal facility) were sampled with portable pumps and measured with both the mAb-EIA and Glucatell assay. Using carboxymethylated curdlan as a standard, the mAb-EIA gave a steep dose-response curve for concentrations between 0.36-15 ng/ml. The mAb-EIA was specific for (1-->3)-beta-D-glucan and was sufficiently sensitive to detect (1-->3)-beta-D-glucan in airborne dust samples. In comparing the EIA results to the values obtained with the Glucatell assay, the correlation was found to be high (coefficient of correlation r(2)=0.91), and the mean ratio of the values was 1.7. Depending on the dust source, either the Glucatell assay or the mAb-EIA gave higher results. The mAb-EIA is sensitive enough to detect (1-->3)-beta-D-glucan in airborne dust samples collected with portable pumps. Thus, the assay is suited for the investigation of the health effects induced by exposure to this class of biologically active molecules.

Health effects of mold in children

Mold is ubiquitous, and exposure to mold and its products of metabolism is unavoidable, whether indoors or outdoors. Mold can produce a variety of adverse health outcomes by four scientifically validated pathophysiologic mechanisms: hypersensitivity, toxicity, infection, and irritation. Some adverse health outcomes have been attributed to mold for which mechanisms of injury are not well defined or are implausible. This article discusses these adverse health outcomes, focusing predominantly on those for which valid associations have been established.

(1-->3)-beta-D-glucan does not induce acute inflammation after nasal deposition

To assess if (1→3)-β-D-glucan, a microbial cell wall agent normally present in pollen, has the ability to produce pollenlike response, sensitive persons received a nasal deposition of two doses of (1→3)-β-D-glucan. The percentage of eosinophils and amount of eotaxin were measured in nasal lavage 30 minutes and 24 hours after challenge. No effect could be demonstrated. The absence of an inflammatory response after (1→3)-β-D-glucan application confirms earlier findings in inhalation studies.

Mycotoxins as harmful indoor air contaminants

Fungal metabolites (mycotoxins) that pose a health hazard to humans and animals have long been known to be associated with mold-contaminated food and feed. In recent times, concerns have been raised about exposures to mycotoxin-producing fungi in indoor environments, e.g., damp homes and buildings. The principal mycotoxins that contaminate food and feed (alfatoxins, fumonisins, ochratoxin A, deoxynivalenol, zearalenone) are rarely if ever found in indoor environments, but their toxicological properties provide an insight into the difficulties of assessing the health effects of related mycotoxins produced by indoor molds. Although the Penicillium and Aspergillus genera of fungi are major contaminants of both food and feed products and damp buildings, the particular species and hence the array of mycotoxins are quite different in these environments. The mycotoxins of these indoor species and less common mycotoxins from Stachybotrys and Chaetomium fungi are discussed in terms of their health effects and the need for relevant biomarkers and long-term chronic exposure studies.

Indoor airborne fungal spores and home characteristics in asthmatic children from Edirne region of Turkey

BACKGROUND

The contribution of indoor fungal exposure to childhood asthma is not completely clear.

OBJECTIVE

To investigate airborne fungal flora within the homes of asthmatic and control children, and to assess the influence of housing characteristics regarding indoor fungi.

METHODS

Forty-seven atopic asthmatic and 23 nonatopic control children were studied. Allergen sensitivity was determined by skin prick tests. A thorough assessment, using a questionnaire and inspection surveys, was carried out. Home visits were made between October 2000 and February 2001. Samples of airborne fungal spores were collected from four rooms by the "open Petri dish" method. Indoor temperature and humidity were measured.

RESULTS

The total indoor fungal colony counts from the living rooms and bedrooms were significantly higher in the asthma group than in controls (p = .012 and p = .003, respectively). The most commonly isolated genus was Cladosporium. Twelve of the asthmatic patients (25.53 %) were found to be sensitive to fungal allergens. The factors found to be associated with indoor fungal growth in logistic regression were visible fungal patches in the bathrooms [(odds ratio (OR) = 5.75; 95 % CI 1.19 to 27.70)], and the age of the house [OR = 4.24; 95 % CI 1.34 to 13.45]. Total fungal colony numbers did not correlate with indoor temperature or humidity.

CONCLUSION

Fungal colony numbers were higher in the homes of asthmatic children than in those of controls. Therefore, indoor fungal exposure may contribute to childhood asthma. Bathrooms were the main source of fungal propagules. Old houses were more prone to fungal growth.

Stachybotrys chartarum: cause of human disease or media darling?

This is a review of the literature of associations of the saprotrophic fungus Stachybotrys chartarum sensu lato with human and animal illnesses. This fungus grows on very wet cellulose-based building materials. S. chartarum has been the subject of considerable media attention because of temporal associations of exposure with unexpected and dramatic outcomes such as infant pulmonary hemosiderosis and neurocognitive damage. It is generally accepted that living or working in mouldy environments is associated with building related asthma, exacerbating asthma in mould-sensitive asthmatics and increased rates of upper respiratory disease. However, such relationships are with building-associated moulds, comprising many species that colonize wet or damp building materials, and are not specific to S. chartarum. There is limited evidence that severe lung damage can occur from building exposure to S. chartarum but possibly only under conditions of exposure that approach those associated with handling contaminated straw. There is no positive evidence in the literature to account for putative neurological damage resulting from exposure to this mould.

Organic dust exposure and work-related effects among recycling workers

OBJECTIVE

Organic dust exposure and work-related symptoms and effects among household waste recycling workers in Materials Recovery Facilities (MRFs) are a concern. MRFs are a central operation where source-segregated, dry, recyclable materials (paper, plastics, cans, etc.) are sorted, mechanically or manually, to market specifications for processing into secondary materials.

METHODS

One hundred and fifty-nine MRF workers (91%) from nine MRFs participated. Measurements of airborne total dust, endotoxin, (1-->3)-beta-D-glucan, and a questionnaire survey were carried out. Blood data was restricted to MRFs 3, 6, and 9 (45 workers). Blood sampling investigated differential cell counts, erythrocyte sedimentation rate (ESR), and immunoglobulin (Ig)E.

RESULTS

Workers exposed to higher amounts of endotoxin and (1-->3)-beta-D-glucan had an increased risk for respiratory symptoms as compared to those with lower exposure. Stomach problems was associated to higher (1-->3)-beta-D-glucan exposure. MRF 3 had a higher (1-->3)-beta-d-glucan exposure compared to 6 and 9, and respiratory symptoms, unusual tiredness, and vomiting were reported more often in MRF 3. Monocyte numbers and ESR were significantly decreased in MRF 3 compared to MRF 6 and 9, but all measured values were within normal ranges.

CONCLUSIONS

The results suggest that MRF workers exposed to higher levels of endotoxin and (1-->3)-beta-D-glucan at their work sites exhibit various work-related symptoms, and that the longer a worker is in the MRF environment, the more likely he is to become affected by various respiratory and gastrointestinal symptoms.

An update on pollen and fungal spore aerobiology

Changes in climate are altering pollen distribution. Predictive modeling can be used to forecast long- and short-term changes in pollen concentrations. Increasing evidence confirms the presence of pollen allergens on small, respirable particles in the air, explaining the occurrence of pollen-season increases in asthma. Like pollens, aboveground indoor fungal aerosols primarily reflect outdoor concentrations. Basement spore concentrations might be higher and reflective of local sources. Fungal presence in the indoor or outdoor air can be monitored on an area basis or with personal monitors. The samples can be analyzed by means of microscopy, culture, DNA probes, HPLC, or immunodetection. Total fungal biomass can be estimated on the basis of measurements of ergosterol or glucan in environmental samples. Unfortunately, there are no generally accepted standards for interpretation of fungal levels in indoor or outdoor air. At present, the best approach to indoor fungal control is moisture control in the indoor environment. This will essentially prevent fungal growth, except from extraordinary events.

Effects after inhalation of (1-->3)-beta-D-glucan and relation to mould exposure in the home

BACKGROUND

Damp conditions indoors favour the growth of microorganisms, and these contain several agents that may cause inflammation when inhaled. Moulds contain a polyglucose in their cell wall, defined as (1-->3)-beta-D-glucan, exhibiting effects on inflammatory cells.

AIM

The aim of the present study was to evaluate whether an inhalation challenge to purified (1-->3)-beta-D-glucan (grifolan) in humans could induce effects on inflammatory markers in blood, and to evaluate whether the reactions were related to the home exposure to (1-->3)-beta-D-glucan.

METHODS

Seventeen subjects in homes with high levels of airborne (1-->3)-beta-D-glucan (G-high) and 18 subjects in homes with low levels of (1-->3)-beta-D-glucan (G-low) underwent two randomised, double-blind inhalation challenges, one to (1-->3)-beta-D-glucan suspended in saline and one to saline alone. A blood sample was taken before and after the challenges, and differential cell count, granulocyte enzymes in serum and the secretion of cytokines from peripheral blood mononuclear cells (PBMC) were measured.

RESULTS

Inhalation challenge with (1-->3)-beta-D-glucan induced a decrease in the secretion of tumour necrosis factor alpha from endotoxin-stimulated PBMC in the G-high group as well as in the G-low group. In the G-high group, the inhalation of (1-->3)-beta-D-glucan induced an increase in blood lymphocytes that was significantly different from the saline-induced effect.

CONCLUSIONS

The results suggest that an inhalation challenge to (1-->3)-beta-D-glucan has an effect on inflammatory cells and this effect may be related to a chronic exposure to moulds at home.