Human Inhalation Study with Zinc Oxide: Analysis of Zinc Levels and Biomarkers in Exhaled Breath Condensate.

Workers in the zinc processing, for example, welding or hot-dip galvanizing, are exposed to aerosols consisting of particles and gases, including zinc oxide (ZnO), which can affect human health. In this study, we addressed the effects of short-term controlled exposure to nano-sized ZnO on the airway inflammatory markers in healthy volunteers. To this end, we determined the influence of ZnO inhalation on the content of zinc and biomarkers (leukotriene B4 (LTB4), peptide leukotrienes (LTC4/D4/E4), 8-iso-PGF2α, pH, and prostaglandin E2 (PGE2)) in exhaled breath condensate (EBC). Sixteen non-smoking subjects (8 females, 8 men) were exposed to filtered air (sham) or ZnO nanoparticles (0.5, 1.0, and 2.0 mg/m3) for 4 h. EBC samples were collected according to specific study design. We found that the peptide leukotrienes were below the limit of quantification (LOQ) in all the EBC samples. ZnO exposure showed no detectable effect on any other parameters investigated when comparing the two groups. The content of Zn in EBC was unaffected by ZnO inhalation at any concentration used. Therefore, we conclude that the evaluation of Zn and biomarker content in EBC would not be a suitable way to assess the exposure to inhaled ZnO.

Cell-biological effects of zinc oxide spheres and rods from the nano- to the microscale at sub-toxic levels.

Zinc oxide particles were synthesized in various sizes and shapes, i.e., spheres of 40-nm, 200-nm, and 500-nm diameter and rods of 40∙100 nm2 and 100∙400 nm2 (all PVP-stabilized and well dispersed in water and cell culture medium). Crystallographically, the particles consisted of the hexagonal wurtzite phase with a primary crystallite size of 20 to 100 nm. The particles showed a slow dissolution in water and cell culture medium (both neutral; about 10% after 5 days) but dissolved within about 1 h in two different simulated lysosomal media (pH 4.5 to 4.8). Cells relevant for respiratory exposure (NR8383 rat alveolar macrophages) were exposed to these particles in vitro. Viability, apoptosis, and cell activation (generation of reactive oxygen species, ROS, release of cytokines) were investigated in an in vitro lung cell model with respect to the migration of inflammatory cells. All particle types were rapidly taken up by the cells, leading to an increased intracellular zinc ion concentration. The nanoparticles were more cytotoxic than the microparticles and comparable with dissolved zinc acetate. All particles induced cell apoptosis, unlike dissolved zinc acetate, indicating a particle-related mechanism. Microparticles induced a stronger formation of reactive oxygen species than smaller particles probably due to higher sedimentation (cell-to-particle contact) of microparticles in contrast to nanoparticles. The effect of particle types on the cytokine release was weak and mainly resulted in a decrease as shown by a protein microarray. In the particle-induced cell migration assay (PICMA), all particles had a lower effect than dissolved zinc acetate. In conclusion, the biological effects of zinc oxide particles in the sub-toxic range are caused by zinc ions after intracellular dissolution, by cell-to-particle contacts, and by the uptake of zinc oxide particles into cells. Graphical headlights • The cytotoxicity of zinc oxide particles is mainly due to the intracellular release of zinc ions. • The size and shape of zinc oxide micro- and nanoparticles has only small effects on lung cells in the sub-toxic range. • Zinc oxide particles are rapidly taken up by cells, regardless of their size and shape. • Zinc oxide particles rapidly dissolve after cellular uptake in endolysosomes.

Discrimination Between Atopic, Allergic, and Asthmatic Volunteers for Human Exposure Studies on Sensory Irritation.

Atopic, allergic, and especially asthmatic subjects might be particularly susceptible to sensory irritation induced by airborne chemicals compared to healthy individuals. Therefore, a good characterization of subjects is essential in inhalation exposure studies on sensory irritants. A total of 105 volunteers, 87% of whom reported to be non-allergic, participated in a medical examination that included skin prick test (SPT), measurements of total IgE, specific IgE (sIgE) to an ubiquitous allergen mix (sx1), and fractionated exhaled nitric oxide (FeNO), as well as pulmonary function and methacholine test. The median value of sIgE to sx1 was 0.20 kU/L (0.07-91.3 kU/L) and correlated significantly with total IgE (28.8 kU/L (2-756 kU/L)) and FeNO (14 ppb (5-100 ppb)). Forty-three subjects (41%) had sIgE to sx1 ≥ 0.35 kU/L and were classified as atopic. Thirty-five subjects, all also sx1-positive, were positive in SPT. Obstruction, small airway disease, and/or bronchial hyperreactivity were diagnosed in 18 subjects. Receiver operating characteristics (ROC) were performed to check whether signs of sensitization are useful to discriminate subjects with and without airway diseases. However, sx1, total IgE, FeNO, and SPT reached only low areas under the curve (AUC: 0.57-0.66). Although predominantly young and, according to their own statements, mostly non-allergic subjects participated in the study, almost half of them were atopic, and 10% had airway disease or bronchial hyperreactivity. This indicates that the validity of self-reported data might be inaccurate. In summary, diversified investigations of the allergy-related health status appear necessary for a thorough characterization of subjects for exposure studies on sensory irritants.

How Healthy Is Healthy? Comparison Between Self-Reported Symptoms and Clinical Outcomes in Connection with the Enrollment of Volunteers for Human Exposure Studies on Sensory Irritation Effects.

Controlled human exposure studies on sensory irritation effects are usually performed with healthy volunteers. Therefore, in most studies pre-screening by a health questionnaire and a detailed medical examination are combined. The aim of this report is to investigate whether self-reported information about smoking and health status is sufficient or whether additional clinical tests are necessary for a successful and safe enrollment of healthy volunteers. There were 409 volunteers (55% female; 17-57 years; 79% non-smokers) who declared interest in participation in the study. However, 87 subjects failed to meet specific inclusion criteria, and further 138 had to be excluded due to the presence of chronic health problems. In effect, 184 subjects passed the initial questionnaire screening and proceed to further examination. Medical examination included electrocardiogram, blood and urine screening, and an olfactory function test. Atopy status was assessed by skin prick or specific IgE testing. Lung function and a methacholine challenge test were performed to assess respiratory health and bronchial hyperresponsiveness. Overall, only 107 non-smoking subjects (58% female; 19-40 years) who had no respiratory diseases, allergies, or chronic illnesses could be finally selected. Out of the 107 subjects, 8 were excluded due to positive cotinine tests, laboratory test results outside the reference range, or atypical ECGs. In another 12 subjects, obstruction or a bronchial hyperreactivity was diagnosed. Among the remaining 87 healthy subjects, 26 were classified as atopic and further two as hyposmic. In conclusion, although young and non-smoking volunteers considered themselves healthy by questionnaire, 20% showed signs of a heart, liver, or airway disease, and additional 24% were classified as atopics. This suggests that more detailed clinical testing may be necessary to safely exclude those who may adversely react to controlled exposure with sensory irritants.

Methodological Implications and Repeatability of Nasal Nitric Oxide: Relevance for Challenge Studies.

There is an interest in assessing changes in nasal NO (nNO) levels as an effect marker of upper airways. In this study, we examined methodologic influences on short and long term repeatability of nNO levels assessed by a portable electrochemical analyzer. Nine atopic and eighteen healthy subjects were exposed for 4 h to ethyl acrylate concentration of 0.05 ppm (sham) and mean concentrations of 5 ppm (either constant 5 ppm or variable 0 to 10 ppm). Sampling of nNO was performed by using passive aspiration during both breath-holding (634 ppb) or calm tidal breathing (364 ppb, p < 0.0001). The intra-session (between-session) repeatability in terms of coefficient of variation was 16.4% (18.5%) using the tidal-breathing and 8.6% (13.0%) using the breath-holding method, respectively. Atopic subjects demonstrated a significant increase in nNO (breath-holding mean 16%, tidal-breathing mean 32%) after applying a constant ethyl acrylate concentration (5 ppm). Our findings suggest that the less elaborate tidal-breathing method might be sufficient to detect significant changes at a group level. Given a lower coefficient of variation of breath-holding we assume there is an advantage of that approach at an individual level. Further research is needed to validate the usefulness of nNO in the evaluation of irritative, non-allergic responses.

Airway and Blood Inflammatory Markers in Waste Collectors.

Waste collectors are exposed to a heterogeneous mixture of bioaerosols able to induce health effects. The study aim was to evaluate inflammatory processes in blood and in the respiratory tract via analysis of atopy and club cell secretory protein 16 (CC16) in serum, exhaled nitric oxide (FeNO), and cellular and soluble mediators in nasal lavage fluid (NALF) and induced sputum (IS). Sixty nine current waste collectors (48% smokers) and 28 former waste collectors (25% smokers) were included in the cross-sectional study. In both groups, 63 and 64% of workers reported complaints of the eyes, nose and/or upper airways. Thirty two percent of the current and 25% of the former workers were classified as atopics. More atopics suffered from rhinitis and conjunctivitis than non-atopics (64% vs. 40% in current workers; 71% vs. 40% in former workers). CC16 values of present non-smokers were significantly higher compared to smokers. In total, FeNO values of 31 participants were lower than 10 ppb, 94% of them were smokers and 85% had respiratory symptoms of lower airways. Most of the IS biomarkers were significantly higher in smokers than in non-smokers. Non-smoking workers with respiratory symptoms of lower airways had slightly elevated mediator IS concentrations compared to asymptomatic non-smokers. We conclude that inflammatory changes in waste collectors are detectable in the content of IS biomarkers, exhaled NO, and serum CC16, which all are influenced by the smoking habit. No significant differences in biomarkers are detectable between current and former waste collectors.

Impact of Internal and External Factors on EBC-pH and FeNO Changes in Humans Following Challenge with Ethyl Acrylate.

Acute effects of ethyl acrylate exposure at 5 ppm for 4 h include changes of pH in exhaled breath condensate (EBC-pH) and exhaled nitric oxide (FeNO). So far, few data have been reported for atopic persons or the impact of the exposure conditions on biomarkers, e.g., constant versus variable application of irritants. Nine atopic and eighteen healthy volunteers without bronchial hyperresponsiveness were exposed for 4 h to ethyl acrylate concentrations of 0.05 ppm (sham), 5 ppm (constant concentration), and 0-10 ppm (variable, mean concentration of 5 ppm) in an exposure laboratory. A positive atopic status was defined according to specific IgE concentrations to common inhalant allergens (sx1 ≥ 0.35 kU/L). Biomarker levels were assessed before and after challenge and adjusted for levels after sham exposure (net response). Ethyl acrylate at constant, but not at variable concentrations induced a significant change in the net responses of EBC-pH and FeNO. Concerning FeNO, this could be observed only for atopic persons. The changes of biomarker levels were related to their baseline values. Biomarker responses to challenge with ethyl acrylate may be influenced by the patterns of application as well as baseline airway inflammation and atopic status of the volunteers.

Effects of bioaerosol exposure on respiratory health in compost workers: a 13-year follow-up study.

OBJECTIVES: To determine the risk of German compost workers developing chronic respiratory effects from long-term exposure to bioaerosols. METHODS: Respiratory health was determined in 74 currently exposed compost workers and 37 non-exposed controls after 13 years of follow-up. In addition, 42 former compost workers (drop-outs) who left their work during the follow-up period were also examined. Respiratory symptoms and working conditions were assessed using identical questionnaires as at baseline. In addition, lung function was measured using the same spirometer as in the initial study. Sera from both surveys were tested for specific IgE and IgG antibodies to moulds and the risk of work-related symptoms was evaluated using regression approaches for prospective studies with binary data. RESULTS: In the follow-up period, the number of participants reporting cough significantly increased in compost workers and drop-outs compared to the controls. Working as a compost worker for at least 5 years increased the relative risk for cough (RR 1.28; 95% CI 1.2 to 1.4) and for cough with phlegm (RR 1.32; 95% CI 1.2 to 1.5). Current and former compost workers had slightly lower predicted percentage of forced expiratory volume in 1 s and predicted percentage of forced vital capacity than controls, but decrease in lung function during follow-up was not different among the 3 groups. In addition, no significant changes could be detected in antibody concentrations. CONCLUSIONS: Our results suggest that chronic exposure to bioaerosols in composting plants is related to a significantly higher risk for cough with phlegm, indicating chronic bronchitis. However, compost workers showed no higher incidence of deterioration of pulmonary function over the study.

Kinetics of chemotaxis, cytokine, and chemokine release of NR8383 macrophages after exposure to inflammatory and inert granular insoluble particles.

Accumulation of macrophages and neutrophil granulocytes in the lung are key events in the inflammatory response to inhaled particles. The present study aims at the time course of chemotaxis in vitro in response to the challenge of various biopersistent particles and its functional relation to the transcription of inflammatory mediators. NR8383 rat alveolar macrophages were challenged with particles of coarse quartz, barium sulfate, and nanosized silica for one, four, and 16h and with coarse and nanosized titanium dioxide particles (rutile and anatase) for 16h only. The cell supernatants were used to investigate the chemotaxis of unexposed NR8383 macrophages. The transcription of inflammatory mediators in cells exposed to quartz, silica, and barium sulfate was analyzed by quantitative real-time PCR. Challenge with quartz, silica, and rutile particles induced significant chemotaxis of unexposed NR8383 macrophages. Chemotaxis caused by quartz and silica was accompanied by an elevated transcription of CCL3, CCL4, CXCL1, CXCL3, and TNFα. Quartz exposure showed an earlier onset of both effects compared to the nanosized silica. The strength of this response roughly paralleled the cytotoxic effects. Barium sulfate and anatase did not induce chemotaxis and barium sulfate as well caused no elevated transcription. In conclusion, NR8383 macrophages respond to the challenge with inflammatory particles with the release of chemotactic compounds that act on unexposed macrophages. The kinetics of the response differs between the various particles.

Clinical Effects, Exhaled Breath Condensate pH and Exhaled Nitric Oxide in Humans After Ethyl Acrylate Exposure.

Ethyl acrylate is an irritant known to affect the upper airways and eyes. An increase of the eye blink frequency in humans was observed during exposure to 5 ppm. Studies on the lower airways are scant and our study objective was the evaluation of pH in exhaled breath condensate (EBC-pH) and nitric oxide in exhaled breath (FeNO) as markers of inflammation. Sixteen healthy volunteers were exposed for 4 h to ethyl acrylate at a concentration of 5 ppm and to sham (0.05 ppm) in an exposure laboratory. Clinical irritation symptoms, EBC-pH (at a pCO2 of 5.33 kPa) and FeNO were assessed before and after exposure. Differences after ethyl acrylate exposure were adjusted for those after sham exposure. 5 ppm ethyl acrylate induced clinical signs of local irritation in the nose and eyes, but not in lower airways. Exposure produced a subtle, but statistically significant, decrease in breathing frequency (1 breath/min; p = 0.017) and a lower EBC-pH (by 0.045 units; p = 0.037). Concerning FeNO, we did not observe significant changes compared to sham exposure. We conclude that local effects induced by 5 ppm ethyl acrylate consist of sensory irritation of eyes and nose. In addition, acute ethyl acrylate exposure to 5 ppm resulted in a net decrease of EBC-pH. Whether that can be interpreted in terms of additional lower airway irritation or already inflammatory alterations set in needs further investigations.

How to diagnose mould allergy? Comparison of skin prick tests with specific IgE results.

BACKGROUND: Diagnosis of mould allergy is complicated due to the heterogeneity of the test material and the decrease in the number of commercial mould skin test solutions that are currently available. OBJECTIVES: The aim of this study was to compare skin prick tests (SPT) from different manufacturers to one another and concurrently with sIgE tests for Aspergillus fumigatus (Asp f), Cladosporium herbarum (Cla h), Penicillium chrysogenum (Pen ch), Alternaria alternata (Alt a) and Aspergillus versicolor (Asp v) to ascertain a feasible diagnostic procedure for mould sensitization. METHODS: In this multi-centre study, 168 patients with mould exposure and/or mould-induced respiratory symptoms were included. Mould SPT solutions were analysed biochemically and tested in duplicate on patients' arms. Specific IgE (sIgE) concentrations to corresponding mould species and mould mix (mx1) were measured by ImmunoCAP. SPTs in accordance with one another and with sIgE were further considered. The test efficiency was calculated using receiver-operating characteristic (ROC) analysis. RESULTS: Mould sensitization was more frequently detected by the SPT (90 of 168) than by the sIgE tests (56 of 168). Concordances of double SPT positives were only sufficient (≥ 80%) for environmental allergens, two Asp f and three Alt a SPT solutions, whereas all other mould solutions revealed concordances < 80%. The antigen content of SPT solutions was positively associated with concordant SPT double values as well as with sIgE. Taking sIgE as the 'positive standard', all mould SPT solutions revealed test efficiencies > 80%, but varied up to 20% in sensitivity and positive predictive value with the exception of Alt a. CONCLUSIONS: SPT solutions are sensitive and essential diagnostic tools for the detection of mould sensitization. Our recommendation for diagnosis would be to test at least Alt a, Asp f and Pen ch using SPT and additional sIgE test to mx1.

Methodological implications in pH standardization of exhaled breath condensate.

The variable amount of dissolved carbon dioxide is one of the main confounding factors of exhaled breath condensate (EBC) pH measurements. There have been many attempts at identifying the optimal approach to displace CO2 as a way to gain reproducible and valid pH values in EBC samples. The aim of the present study was to assess the correlation of pH and pCO2 in untreated, neat EBC samples and, after deaeration, to reevaluate the standardization of CO2 as a means to obtain valid pH values. A further aim was to evaluate the impact of deaeration on the acid-base balance in EBC samples. EBC was collected from seven female and 31 male subjects. The pH and pCO2 values immediately determined in untreated, neat EBC samples were strongly correlated (rp = -0.723, p < 0.0001). This correlation was not observed after deaeration with argon (rs = 0.264, p = 0.109). Based on a regression function for the pH/pCO2 relationship, the calculated pH at a pCO2 of 5.33 kPa was 6.07 (IQR 5.99, 6.20). No significant difference was observed between the pH measured in neat EBC samples and those calculated after deaeration with regression function and measured neat pCO2. Our data suggest that pCO2 is the most important confounder of pH measurement in EBC samples and, when adjusting for pCO2, the acid-base balance of EBC samples is not significantly influenced by the process of deaeration. Furthermore, measurement with a blood-gas analyzer and standardization of pH for pCO2 allows sensitive assaying of EBC samples. Therefore, this method provides a basis for detection of even small changes in airway pH due to inhalative exposure or respiratory disease.

Evaluation of Airway Inflammation in Compost Workers Exposed to Bioaerosols Using Exhaled Breath Condensate and Fractional Exhaled Nitric Oxide.

Occupational bioaerosol exposures are capable to cause respiratory diseases. We studied the relationship between exposure to bioaerosols and biomarkers' concentration in exhaled breath condensate (EBC) and fractional exhaled nitric oxide (FeNO) in 119 bioaerosol-exposed compost workers taking into account atopy and smoking habits. Atopy was classified according to specific IgE concentrations to common inhalant allergens (sx1). Bioaerosol exposure was estimated according to job title, duration of employment, results of ambient monitoring at the workplaces, and shift time worked under protection of filtered air supply. Concentrations of 8-iso-prostaglandin F2α (8-iso-PGF2α), prostaglandin E2 (PGE2), leukotriene B4 (LTB4), and acid-base balance (pH) in EBC and FeNO were assessed in 59 never-smoking (NS) and 60 smoking (S) compost workers. We found that atopic subjects were equally distributed among NS and S (n=16 each). Levels of 8-iso-PGF2α were significantly higher in workers considered highly exposed to bioaerosols than in low exposed workers (86.6 (66.1; 128.8) pg/mL vs. 74.4 (56.3; 96.7) pg/mL, p=0.047). No associations could be observed between exposures and biomarkers concerning compost workers in total, but there were some in atopic workers (duration of employment and FeNO: r=0.376, p=0.041; filtered air supply and FeNO: r=-0.335, p=0.071). Smokers had significantly lower pH values compared to NS (non-atopic, p=0.041; atopic p=0.050). In conclusion, EBC and FeNO might be useful tools for monitoring of inflammation due to bioaerosol exposures, especially in atopic subjects. Besides smoking also atopy should be considered when investigating airway inflammation.

Cellular and Soluble Inflammatory Markers in Induced Sputum of Composting Plant Workers.

Inflammatory processes, including respiratory symptoms, can be induced among workers in composting plants exposed to bioaerosols containing microorganisms and their compounds. We evaluated inflammatory processes in the lower respiratory tract via cellular and soluble mediator profiles in induced sputum (IS). IS samples of 140 current (35% smokers) and 49 former compost workers (29% smokers) as well as 29 white-collar workers (17% smokers) were collected and analyzed for the cell count and composition, and for soluble biomarkers. Significant differences between current and former compost workers and white-collar workers were detected for total cell count (p=0.0004), neutrophils (p=0.0045), sCD14 (p=0.008), and 8-isoprostane (p<0.0001). IS of non-smoking former compost workers showed lower concentrations of IL-8, total protein, immunoreactive MMP-9 and sCD14, compared with non-smoking current compost workers. 10.1% of the study population was suffering from chronic bronchitis with significant differences (p=0.018) between former compost workers (24.5%), current workers (5%), and white-collar workers (10.3%). Significantly lower IL-8 (p=0.0002), neutrophils (p=0.001), and MMP-9 (p=0.0023) values were measured in healthy subjects compared with subjects with chronic bronchitis. In conclusion, changes in lower airways were detected by analysis of biomarkers in IS of current exposed and, to a lesser extent, in IS of former compost workers. These effects are especially pronounced in subjects with chronic bronchitis.

Different Patterns in Changes of Exhaled Breath Condensate pH and Exhaled Nitric Oxide After Ozone Exposure.

Study objective was the evaluation of pH in exhaled breath condensate (EBC-pH) and nitric oxide in exhaled breath (FeNO) as biomarkers of ozone induced inflammation. We recently demonstrated that an ozone exposure of 240 ppb is sufficient to reduce lung function indices. We enrolled ten healthy subjects exposed in an intermittent exercise protocol to ozone concentrations of 240 ppb and 40 ppb (sham exposure). EBC-pH and FeNO were assessed before (pre), immediately post (post), and 16 h after exposure (16 h). Findings are that compared to baseline, EBC-pH was significantly higher immediately after sham and ozone exposures, but not 16 h later. There was a negative net change in EBC-pH after adjusting for effects after sham exposure (net-ΔpHpost -0.38%, net-ΔpH16h -0.23%). Concerning FeNO, we observed no changes of values after sham exposure compared to baseline, but measured a significant lower net response at the end of exposure (net-ΔFeNOpost -17.5%) which was transient within 16 h (net-ΔFeNO16h -9.4%). We conclude that exercise known to enhance EBC-pH may compensate for EBC acidification associated with inflammation resulting in diminished change of this biomarker. Ozone imposes an oxidative burden and reactions between reactive oxygen species and NO might be an explanation for reduced FeNO levels.

Prevalence of work-related rhino-conjunctivitis and respiratory symptoms among domestic waste collectors.

Waste collectors may suffer from acute and chronic health effects caused by organic dust (bioaerosols). Pathophysiological symptoms may originate either from allergic or irritative pathomechanisms, but an explicit distinction of the etiology is often complicated although crucial for proper risk assessment and workplace prevention. In this cross-sectional study, a total of 69 male waste collectors from the Ruhr area in Germany underwent a customized testing protocol including a modified questionnaire, basic clinical examination, spirometry, and immunologic parameters. Subjects were classified according to their work tasks into loaders (n=27), floaters (n=29), and drivers (n=13). We found that a high percentage of the workers had complaints (eyes 29.0%, nose 39.1%, and cough 34.8%) which were strongly work-related. Multiple logistic regression analyses indicated that duration of employment in waste collection (per 10 years) was associated with an increased prevalence of cough (OR=1.64, 95% CI 0.81; 3.35) and chronic bronchitis (OR=2.18, 95% CI 0.80; 5.92). An association between rhinitis and cough (OR=2.62, 95% CI 0.94; 7.27) was found, which supports the association between the prevalence of upper and lower airway disease. Furthermore, when adjusting for smoking status, atopic subjects suffered more frequently from irritation of the lower airways as indicated by cough (OR=2.71, 95% CI 0.91; 8.08). In conclusion, the study demonstrates associations between the prevalence of upper and lower airway disease in waste collectors. Notably, an underlying allergic disease in waste collectors could be suspected more commonly than previously reported.

Occupational allergic respiratory diseases in garbage workers: relevance of molds and actinomycetes.

Exposures to molds and bacteria (especially actinomycetes) at workplaces are common in garbage workers, but allergic respiratory diseases due to these microorganisms have been described rarely. The aim of our study was a detailed analysis of mold or bacteria-associated occupational respiratory diseases in garbage workers. From 2002 to 2011 four cases of occupational respiratory diseases related to garbage handling were identified in our institute (IPA). Hypersensitivity pneumonitis (HP) was diagnosed in three subjects (cases 1-3, one smoker, two non-smokers), occupational asthma (OA) was diagnosed in one subject (case 4, smoker), but could not be excluded completely in case 2. Cases 1 and 2 worked in composting sites, while cases 3 and 4 worked in packaging recycling plants. Exposure periods were 2-4 years. Molds and actinomycetes were identified as allergens in all cases. Specific IgE antibodies to Aspergillus fumigatus were detected exclusively in case 4. Diagnoses of HP were essentially based on symptoms and the detection of specific IgG serum antibodies to molds and actinomycetes. OA was confirmed by bronchial provocation test with Aspergillus fumigatus in case 4. In conclusion, occupational HP and OA due to molds occur rarely in garbage workers. Technical prevention measures are insufficient and the diagnosis of HP is often inconclusive. Therefore, it is recommended to implement the full repertoire of diagnostic tools including bronchoalveolar lavage and high resolution computed tomography in the baseline examination.

Pulmonary lesions and serum levels of soluble Fas (sCD95) in former hard coal miners.

OBJECTIVE: Fas/APO-1 (CD95) and Fas Ligand (FasL) is a major mediator system that activates programmed cell death (apoptosis) and is most important for pulmonary cellular homeostasis. Another form of Fas, circulating soluble Fas (sCD95), produced by alternative mRNA splicing antagonizes the cell-surface Fas function. It was the aim of the study to test the hypothesis that the Fas/FasL system is implicated in the development of silica-induced pulmonary nodular lesions. MATERIAL AND METHODS: We investigated the serum levels of sCD95 in 55 former hard coal miners. Coal workers' pneumoconiosis (CWP) was assumed when the profusion of small round opacities according to the ILO 2000 classification system was 1/1 or greater. Analyses of sCD95 were performed by a sandwich ELISA. RESULTS: Radiologic CWP was found in 34 of the 55 individuals. The age of subjects with and without CWP was similar (73.5 (SD 7.2) years vs. 73.5 (7.1) years; P = 0.924). sCD95 could be quantified in all samples; significantly higher levels were observed in subjects with radiologic signs of CWP (914 (752-1251) pg/ml vs. 632 (509-804) pg/ml, P < 0.001). However, there was no relationship between sCD95 serum concentrations and the quantity of profusion according to ILO. CONCLUSIONS: The hypothesis of elevated sCD95 concentrations in CWP was corroborated. The usefulness of sCD95 for prevention and diagnosis of CWP and other forms of silica-induced fibrosis needs to be established by epidemiological studies.

Factors controlling bacterial attachment and biofilm formation on medium-chain-length polyhydroxyalkanoates (mcl-PHAs).

Polyhydroxyalkanoate (PHA) is a versatile class of biodegradable and biocompatible biopolyesters accumulated by many bacteria as intracellular carbon storage compound. The largest subclass consists of medium-chain-length (mcl) PHA which has a large potential in medical applications where flexible or elastomeric materials are required. Different extraction and purification methods for mcl-PHA are known to result in variations of polymer purities. In this study it was assessed whether this difference in quality may increase risk of failure of the implant material by enhanced colonization by Gram-negative and Gram-positive model pathogens (Staphylococcus aureus and Escherichia coli curli). Two types of mcl-PHA copolymers, poly(3-hydroxyoctanoate) (PHO) and the less known poly(3-hydroxyundecanoate) (PHUA), were evaluated for an impact of monomeric unit composition and degree of polymer purity on colonization by the model pathogens. It was found that film formation by bacteria on purified PHO and PHUA coatings was lower or similar to the one observed for polystyrene controls. The presence of proteins and lipopolysaccharide impurities originating from biotechnological production contributed to an increase in biofilm development probably by triggering the attachment of bacterial cells. In addition it was found that the model strains used differed significantly in colonizing the surfaces. For both types of mcl-PHAs E. coli curli was always a better biofilm former than S. aureus, which could be explained by the presence of curli (protein) fibers and a less hydrophilic cell wall.

Ether oxygenate additives in gasoline reduce toxicity of exhausts.

UNLABELLED: Fuel additives can improve combustion and knock resistance of gasoline engines. Common additives in commercial fuels are "short-chain, oxygen containing hydrocarbons" such as methyl tert-butyl ether (MTBE) and ethyl tert-butyl ether (ETBE). Since these additives change the combustion characteristics, this may as well influence toxic effects of the resulting emissions. Therefore we compared toxicity and BTEX emissions of gasoline engine exhaust regarding addition of MTBE or ETBE. Non-reformulated gasoline served as basic fuel. This fuel was supplemented with 10%, 20%, 25% and 30% ETBE or 15% MTBE. The fuels were combusted in a gasoline engine at idling, part load and rated power. Condensates and particulate matter (PM) were collected and PM samples extracted with dichloromethane. Cytotoxic effects were investigated in murine fibroblasts (L929) using the neutral red uptake assay and mutagenicity using the bacterial reverse mutation assay. BTEX emissions were analyzed by gas chromatography. RESULTS: PM-extracts showed mutagenicity with and without metabolic activation. Mutagenicity was reduced by the addition of MTBE and ETBE, 10% ETBE being most effective. The condensates produced no significant mutagenic response. The cytotoxicity of the condensates from ETBE- and MTBE-reformulated fuels was reduced as well. The BTEX content in the exhaust was lowered by the addition of MTBE and ETBE. This effect was significantly related to the ETBE content at rated power and part load. CONCLUSIONS: Addition of MTBE and ETBE to fuels can improve combustion and leads to decreased toxicity and BTEX content of the exhaust. Reduction of mutagenicity in the PM-extracts is most probably caused by a lower content of polycyclic aromatic hydrocarbons.