Respiratory Exposure Research Articles

Spatial distribution of the size-fractional PNC and Pedestrian exposure to PM at an urban signalized intersection

To evaluate the respiratory health risk of pedestrians at signalized intersections, it is crucial to accurately investigate their spatial distribution of particulate matter (PM) in the air and the respiratory exposure dose to the public. The particle number concentrations (PNCs) of different sizes (10–2500 nm) along the horizontal and vertical vibrations of the intersection were measured in Xi'an, China, and the respiratory deposition dose (RDD) rate of pedestrians was calculated to estimate the pedestrian exposure level. The mean PNC at the intersection's entrance (1.59 × 104 # cm−3) was larger than at its exit (1.34 × 104 # cm−3) irrespective of the particle mode. At the exit, moreover, the PNC values decreased exponentially with increasing distance from the parking baseline of the intersection, while no such damping characterized the entrance to it. Concerning the vertical vibration of the intersection, both nucleation and Aitken modes of PNC peaked at a 0.4-m height and the maximum PNC in the accumulation mode and coarse mode appeared at a height of 3.4–4.5 m. Average RDD rate at the signalized intersection's entrance and exit was respectively 8.103 μg h−1 and 7.523 μg h−1. For this same intersection, the highest PM exposure dose was 8.444 μg h−1 for the elderly, followed by 8.061 μg h−1 for adults, and 3.221 μg h−1 for children.

Indoor house dust-borne fungi and risk of allergic respiratory diseases in Baghdad city

BackgroundIndoor allergens are important components of airborne allergens, and studies have linked allergic respiratory diseases (ARDs) and exposure to aeroallergens. ObjectivesThis study sought to identify fungi in house dust from four regions in Baghdad city, and to assess the risks of ARD and asthma associated with indoor fungi. MethodsHouse dust was collected from 84 homes located in four major areas in Baghdad; locations 1, 2, 3 and 4 (north, west, south-west and south of Baghdad, respectively). The dust samples were cultured to identify fungal genera. ResultsSeventy-nine mold isolates belong to nine genera (Aspergillus, Rhizopus, Penicillium, Chrysonilia, Mucor, Fusarium, Cladosporium, Alternaria and Helminthosporium), as well as five yeast isolates, were identified. Aspergillus was the most common type of mold (56.0%), while Alternaria and Helminthosporium were the least frequent (each with 1%). The distribution of these fungi showed variation according to location, but the difference was not significant. ARD in general and asthma in particular were detected in 50.0 and 14.3% of households, respectively. Both types of allergy were significantly associated with mold genera and with the number of households and rooms, as well as the availability of gardens and trees. ConclusionsThe study indicated that fungi are significant indoor determinants of ARD and asthma in the city of Baghdad.

Cytotoxicity and genotoxicity of low-dose vanadium dioxide nanoparticles to lung cells following long-term exposure

Vanadium dioxide nanoparticles (VO2 NPs) have been massively produced and widely applied due to their excellent metal-insulator transition property, making it extremely urgent to evaluate their safety, especially for low-dose long-term respiratory occupational exposure. Here, we report a comprehensive cytotoxicity and genotoxicity study on VO2 NPs to lung cell lines A549 and BEAS-2B following a long-term exposure. A commercial VO2 NP, S-VO2, was used to treat BEAS-2B (0.15–0.6 μg/mL) and A549 (0.3–1.2 μg/mL) cells for four exposure cycles, and each exposure cycle lasted for 4 consecutive days; then various bioassays were performed after each cycle. Significant proliferation inhibition was observed in both cell lines after long-term exposure of S-VO2 at low doses that did not cause apparent acute cytotoxicity; however, the genotoxicity of S-VO2, characterized by DNA damage and micronuclei, was only observed in A549 cells. These adverse effects of S-VO2 were exposure time-, dose- and cell-dependent, and closely related to the solubility of S-VO2. The oxidative stress in cells, i.e., enhanced reactive oxygen species (ROS) generation and suppressed reduced glutathione, was the main toxicity mechanism of S-VO2. The ROS-associated mitochondrial damage and DNA damage led to the genotoxicity, and cell proliferation retard, resulting in the cellular viability loss. Our results highlight the importance and urgent necessity of the investigation on the long-term toxicity of VO2 NPs.

Intracellular GSH/GST antioxidants system change as an earlier biomarker for toxicity evaluation of iron oxide nanoparticles

Glutathione (GSH) and glutathione-S-transferases (GSTs) are two frontlines of cellular defense against both acute and chronic toxicity of xenobiotics-induced oxidative stress. The contribution of GSH and GST enzymes to signaling pathways and the regulation of GSH homeostasis play a central role in the detoxification of numerous environmental toxins and impurities. Iron oxide nanoparticles stemmed from traffic exhaust, steel manufacturing, or welding as a potential environmental pollution can lead to adverse respiratory outcomes and aggravate the risk of chronic health conditions via persistent oxidative stress. In this work, two kinds of acute exposure experiments of iron oxide (Fe2O3 and Fe3O4) nanoparticles in cells and in vivo were conducted to evaluate the GSH levels and GST activity. Our current research presented Fe3O4 nanoparticles at lower concentrations (≤100 μg/ml) seem to be more toxic to the human bronchial epithelial cells as their consumption of GSH and decrease of GST activity. The catalysis activity of Fe3O4 nanoparticles per se may contribute to the intracellular GSH consumption along with inhibition of glutathione-S-transferase class mu 1 and P (GSTM1 and GSTP1) active site and expression decrease of GSTM1 and GSTP1. Accordingly, the GSH consumption and decrease in GST activity directed to the further lipid peroxidation regarded as an earlier marker for toxicity evaluation of iron oxide nanoparticles, and relevant intervention may be effective for prevention of respiratory exposure induced damage from iron oxide nanoparticles.

Relationship between metabolic syndrome and pulmonary function in workers with respiratory dust exposure in Iran

Aimswe designed a study to investigate the relationship between metabolic syndrome (MetS) and lung function in workers with dust exposure based on five years of longitudinal study data. MethodsIn this historical cohort study that conducted in iron ore mine, non-smoker male workers who exposed to dust, were enrolled. MetS was determined according to the National Cholesterol Education Program Adult Treatment Panel III. New spirometry parameters and spirometry from 5 years ago, were compared. ResultsIn this study 192 workers were identified without MetS and 77 with MetS. The mean of all lung parameters was lower in subjects with MetS, but it was not statistically significant. The median decline in FEV1 and FVC in 5 years was greater in subjects with MetS but were only significant for a decline in FEV1 (P-Value = 0.04). Linear regression analysis showed a significant relationship between a decline in FEV1 and waist circumference (P-Value = 0.001) when adjusted for age, BMI, physical activity level. ConclusionIn this study, a significant association between mean decline in FEV1 in 5 years and MetS in dust-exposed workers was demonstrated. Decline in FEV1 in 5 years was significantly associated with a Waist circumference as one of the components of MetS.

Pathophysiological profile of awake and anesthetized pigs following systemic exposure to the highly lethal ricin toxin

Ricin, a plant-derived toxin originating from the seeds of Ricinus communis (castor bean plant), is one of the most lethal toxins known. To date, no in-depth study of systemic exposure to ricin in a standardized large animal model has been reported. This study details for the first time the pathophysiological hemodynamic profile following systemic/intramuscular exposure to the ricin toxin in a porcine model by comprehensive cardiorespiratory monitoring of awake and anesthetized pigs. Unlike respiratory exposure to ricin, which is characterized by the development of acute respiratory distress syndrome, following intramuscular exposure to ricin respiratory parameters were grossly unaffected, however the hemodynamics of both awake and anesthetize pigs were unsustainably compromised. We show that in the early phase until approximately 24 h post-exposure, cardiac output is not impaired although one of its components, stroke volume, is relatively low. This is due to compensatory increase in heart rate, which eventually becomes insufficient. Later, distributive shock develops, characterized by severe vasodilatation (decreased systemic vascular resistance), low central venous oxygen saturation and elevation of venous-to-arterial carbon dioxide difference indicating increase in tissue oxygen demand not met by cardiac supply. These findings serve as a basis for further studies to evaluate the ability of supportive treatments such as vasoactive and inotropic drugs, to postpone the hemodynamic deterioration and thus expand the therapeutic window for the anti-ricin treatment. Such studies are of crucial importance for judicious treatment of victims of acts of bioterrorism or of intentional self-poisoning.

Asymptomatic carriage of canine infectious respiratory disease complex pathogens among healthy dogs.

The objectives of this study were to determine the prevalence of canine infectious respiratory disease pathogens among asymptomatic client-owned dogs, and to compare the risks of asymptomatic pathogen carriage between client-owned dogs and dogs in an animal shelter. Pooled tonsillar, conjunctival and nasal cavity swabs from asymptomatic client-owned dogs (n=133) were tested using a real-time polymerase chain reaction canine respiratory panel. Identical samples from asymptomatic dogs in an animal shelter (n=295) were similarly tested for selected pathogens. Risk differences were calculated between client-owned dogs and shelter dogs for each of the respiratory pathogens included in the analyses. A total of 15 of 133 (11.3%) asymptomatic client-owned dogs were positive for at least one pathogen in the complex. Seven dogs (6.1%) were positive for M. cynos, six (5.2%) were positive for B. bronchiseptica, two (1.7%) were positive for canine herpesvirus type 1 and two (1.7%) were positive for canine respiratory coronavirus. For all eight pathogens tested in both groups, the proportion of positive cases was higher among shelter dogs than among client-owned dogs. Shelter dogs had a higher risk for M. cynos (0.18, 95% confidence interval: 0.12 to 0.25), canine respiratory coronavirus (0.15, 95% confidence interval: 0.10 to 0.19), canine distemper virus (0.06, 95% confidence interval: 0.03 to 0.09), and canine pneumovirus (0.05, 95% confidence interval: 0.03 to 0.08) than client-owned dogs. Odds ratios for M. cynos (0.31, 95% confidence interval: 0.08 to 0.92) and canine respiratory coronavirus (0.05, 95% confidence interval: 0.01 to 0.18) were significantly different between client-owned and shelter dogs. In all cases except for canine herpesvirus type 1, dogs within the shelter population were observed to be at higher risk of exhibiting asymptomatic carriage of a respiratory pathogen as compared to client-owned dogs. The strength of this association was strongest for M. cynos and canine respiratory coronavirus. The risk of canine infectious respiratory disease pathogen exposure posed by asymptomatic client-owned dogs is poorly defined. This study also corroborates previous reports of high canine infectious respiratory disease prevalence among clinically healthy shelter dogs, and further determined that the overall prevalence of canine infectious respiratory disease pathogen carriage among clinically healthy client-owned dogs is low but is highest for the traditional pathogen B. bronchiseptica and the emerging pathogen M. cynos.

Metabolomics screening of serum biomarkers for occupational exposure of titanium dioxide nanoparticles

Although nanotoxicology studies have shown that respiratory exposure of titanium dioxide nanoparticles (TiO2 NPs) could induce adverse health effects, limited biomarkers associated with occupational exposure of TiO2 NPs were reported. The purpose of this study is to screen serum biomarkers among workers occupationally exposed to TiO2 NPs using metabolomics. Compared with the control group, a total of 296 serum metabolites were differentially expressed in the TiO2 NPs-exposed group, of which the relative expression of 265 metabolites increased, and the remaining 31 decreased. Three machine learning methods including random forest (RF), support vector machines (SVM), and boruta screened eight potential biomarkers and simultaneously selected a metabolite, Liquoric acid. Through multiple linear regression analysis to adjust the influence of confounding factors such as gender, age, BMI, smoking and drinking, occupational exposure to TiO2 NPs was significantly related to the relative expression of the eight potential biomarkers. Meanwhile, the receiver operating characteristic curves (ROCs) of these potential biomarkers had good sensitivity and specificity. These potential biomarkers were related to lipid peroxidation, and had biological basis for occupational exposure to TiO2 NPs. Therefore, it was demonstrated that the serum metabolites represented by Liquoric acid were good biomarkers of occupational exposure to TiO2 NPs.

Regulation of Th17 CD4 T Cell Responses During Pulmonary Group A Streptococcus (GAS) Infections by Dendritic cells

Abstract The respiratory mucosa serves as the first line of cellular immune defense against respiratory pathogen exposure. Prior to the use of antibiotics, GAS accounted for 2–5% of pulmonary bacterial infections and has been associated with secondary bacterial pneumonia following influenza virus infections particularly during pandemics. While studies examining the immune response within the lower airways of the lung during GAS pneumonia have been limited, current findings suggest that nasal infections that elicit both Th17 and antibody (Ab) responses reduce disease and colonization. Given the role that local dendritic cell (DC): T cell interactions within the lungs have been demonstrated to have in other infections, our hypothesis is that pulmonary DC contribute to protective Th17 CD4 T cell responses during GAS infections. Our findings suggest that GAS infection induces the recruitment of a novel dendritic cell subset into the lungs from the blood whose accumulation correlates with local Th17 responses. Depletion of the DC subset results in reduced pulmonary Th17 responses and increased mortality. Therefore, our result suggest that this DC subset is critical for local Th17 responses and control of pulmonary GAS infections. An improved understanding of the contribution of these DC to the regulation of Th17 and other CD4 T cell responses during GAS infection may allow targeted therapy to boost and shape the local CD4 T cell response and anti-GAS immunity.

Respiratory exposure to putative Gulf War toxins induces phenotypic and transcriptional alterations with effector dysfunction in alveolar macrophages

Abstract Respiratory disorders including chronic obstructive pulmonary disease, asthma, and increased susceptibility to lung infections are a prominent component of Gulf War Illness (GWI). Although the mechanisms of GWI are unknown, chronic immune dysfunction is a consistent factor of this multi-symptomatic disorder. Alveolar macrophages (AMs) represent the predominant mononuclear phagocytes of the pulmonary mucosa, orchestrating the host response to pathogens and environmental stimuli via balanced induction of inflammatory, anti-inflammatory, and pro-resolution mediators. Utilizing commercially available instrumentation, we evaluated the effect of aerosolized exposure to two putative GW toxins, the pesticide malathion and diesel exhaust particulate (DEP), on the immune composition and inflammatory response of the lung in FVB/N mice. Toxin exposure resulted in gross lung pathology with variable increases in protein, lactose dehydrogenase, and cytokines in bronchoalveolar lavage (BAL). Aerosolized toxin exposure reduced AMs in the lung and BAL, associated with a shift to wound-healing phenotypes and concomitant influx of monocyte-derived progenitors from the circulation. Exposure to DEP and malathion, either alone or in combination, induced varying levels of dysfunction in flow-sorted AMs ex vivo as determined by inhibited migration, cytokine production, and phagocytosis. Toxin-induced alterations were associated with unique transcriptional profiles following RNA sequencing analysis. Collectively, these findings suggest that respiratory toxin-induced macrophage dysfunction may establish a state of frustrated immune resolution underlying the chronic immunopathology of respiratory GWI.

Role of ILC2 in Viral-Induced Lung Pathogenesis

Innate lymphoid type-2 cells (ILC2) are a population of innate cells of lymphoid origin that are known to drive strong Type 2 immunity. ILC2 play a key role in lung homeostasis, repair/remodeling of lung structures following injury, and initiation of inflammation as well as more complex roles during the immune response, including the transition from innate to adaptive immunity. Remarkably, dysregulation of this single population has been linked with chronic lung pathologies, including asthma, chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrotic diseases (IPF). Furthermore, ILC2 have been shown to increase following early-life respiratory viral infections, such as respiratory syncytial virus (RSV) and rhinovirus (RV), that may lead to long-term alterations of the lung environment. The detrimental roles of increased ILC2 following these infections may include pathogenic chronic inflammation and/or alterations of the structural, repair, and even developmental processes of the lung. Respiratory viral infections in older adults and patients with established chronic pulmonary diseases often lead to exacerbated responses, likely due to previous exposures that leave the lung in a dysregulated functional and structural state. This review will focus on the role of ILC2 during respiratory viral exposures and their effects on the induction and regulation of lung pathogenesis. We aim to provide insight into ILC2-driven mechanisms that may enhance lung-associated diseases throughout life. Understanding these mechanisms will help identify better treatment options to limit not only viral infection severity but also protect against the development and/or exacerbation of other lung pathologies linked to severe respiratory viral infections.

Assessment of home care aides’ respiratory exposure to total volatile organic compounds and chlorine during simulated bathroom cleaning: An experimental design with conventional and “green” products

Home care (HC) aide visits to clients’ homes often involve cleaning and disinfecting (C&D) bathrooms. Some ingredients in C&D household products are associated with respiratory illness, including sodium hypochlorite (bleach) and quaternary ammonium compounds (quats). “Green” products may be safer for the environment, however there are limited quantitative evaluations of their respiratory risks. This study assessed airborne concentrations and time profiles of total volatile organic compounds (TVOC) and chlorine generated during typical bathroom cleaning performed by aides using conventional and green products. Aides performed cleaning tasks in a simulated residential bathroom constructed in an environmental air sampling laboratory. A balanced experimental design involved each aide coming to the lab for four visits during which she performed two 20-min cleaning sessions using one of three C&D products (bleach-based, 1–5% sodium hypochlorite by weight; quats-based, 0.1–1% by weight quaternary ammonium compounds; and “green,” 0.05% by weight thymol, a component of botanical thyme oil) or distilled water as a control. TVOC and chlorine direct reading instruments were attached to aides with sample inlets located in the breathing zone. Ten-second averages of TVOC and chlorine gas concentrations and instantaneous peak concentrations were recorded for the sessions’ duration. TVOC concentrations by methods of C&D application (spraying, streaming, wiping) also were evaluated. The study completed 169 air sampling sessions with 22 aides. The quats-based product generated more than twice the average TVOC concentrations (mean = 1,210 ppb) than the bleach-based (mean = 593 ppb) or green (mean = 498 ppb) products. Each product generated TVOC concentrations that rose rapidly within the first few minutes of application. Spraying produced the highest TVOC exposures, wiping the lowest. Thirteen aides (65%) experienced peak chlorine exposures above the OSHA PEL ceiling limit (1 ppm) when using the bleach-based product. HC aides may experience respiratory hazards from use of conventional or green C&D products formulated with bleach or other respiratory irritants and sprayed in small, poorly ventilated spaces typical of bathrooms. Spraying should be avoided.

Evaluating spatial patterns of seasonal ozone exposure and incidence of respiratory emergency room visits in Dallas-Fort Worth.

BackgroundIn urban environments, environmental air pollution poses significant risks to respiratory health. Moreover, the seasonal spatial variability of the air pollutant ozone, and respiratory illness within Dallas-Fort Worth (DFW) is not well understood. We examine the relationships between spatial patterns of long-term ozone exposure and respiratory illness to better understand impacts on health outcomes. We propose that this study will establish an enhanced understanding of the spatio-temporal characteristics of ozone concentrations and respiratory emergency room visits (ERV) incidence.MethodsAir pollution data (ozone) and ERV incidence data from DFW was used to evaluate the relationships between exposures and outcomes using three steps: (1) develop a geostatistical model to produce quarterly maps of ozone exposure for the DFW area; (2) use spatial analysis techniques to identify clusters of zip codes with high or low values of ozone exposure and respiratory ERV incidence; and (3) use concentration-response curves to evaluate the relationships between respiratory ERV incidence and ozone exposure.ResultsRespiratory ERV incidence was highest in quarters 1 and 4, while ozone exposure was highest in quarters 2 and 3. Extensive statistically significant spatial clusters of ozone regions were identified. Although the maps revealed that there was no regional association between the spatial patterns of high respiratory ERV incidence and ozone exposure, the concentration-response analysis suggests that lower levels of ozone exposure may still contribute to adverse respiratory outcomes.

Determinants of Skin and Respiratory Exposure to Lufenuron During Spraying and Re-entry in Italian Ornamental Plants Greenhouses.

The aim of this study was to evaluate dermal and respiratory exposure of workers to Lufenuron during spraying and re-entry on ornamental plants (stapling) in greenhouses. Potential and real skin exposure were evaluated using filter paper pads, hand contamination by washing, and respiratory exposure by personal air sampling. Dislodgeable foliar residues (DFRs) during re-entry were determined in order to calculate the dermal transfer factor (DTF). Lufenuron was analysed by liquid chromatography-mass detection. Respiratory dose (ReD) was calculated on the basis of a lung ventilation of 15-20 l min-1 and absorbed doses assuming a skin penetration of 13% and a respiratory retention of 100%. During stapling, from the dependence of exposure of hands from DFRs, the mean DTF was 0.575 cm2 h-1 (geometric mean). The ReD was 68.7-74.6 and 0.022-0.636% of the total real dose during spraying and stapling, respectively. The absorbed doses, 0.144-0.171 and 0.005-0.124 µg kg bw-1 during spraying and stapling, respectively, were less than the acceptable operator exposure level of 10 µg kg bw-1. Proper use of equipment and personal protective equipment and personal hygiene are aspects of fundamental importance on which workers must be trained. Adequate occupational hygiene studies are needed to support and verify working practices.

Assessment of respiratory dust exposure and lung functions among workers in textile mill (Thamine), Myanmar: a cross-sectional study

BackgroundAirborne dusts are being potentially harmful for workers in occupational environment. Exposure to respirable dust is the most important concern in textile workers for the widespread of occupational lung diseases, especially more serious in developing countries. The aim of the study was to assess the respirable dust exposure and associated factors of lung functions among textile workers.MethodsA cross-sectional study was carried out at a textile mill (Thamine), Yangon Region, from April to December, 2018 and a total of 207 textile workers were randomly selected by using a multistage sampling procedure. Data were collected by using a structured questionnaire for respiratory symptoms, an air sampling pump for assessment of respirable dust exposure, and a spirometer for testing the lung functions. Logistic regression analysis was performed to assess the associated factors of lung functions. Odds ratios with a 95% confidence interval were computed for strength of associations at the significance level of α ≤ 0.05.ResultsThe mean (± standard deviation, SD) respirable dust exposure was 3.3 mg/m3 (± 0.69) and the prevalence of increased respirable dust exposure (> 3 mg/m3) was 50.7%. The level of respirable dust exposure was highest in the textile workers involving at twisting department. The means (± SD) spirometry values were FVC 82.8% (± 17.8), FEV1 83.6% (± 18.5), and FEV1/FVC 0.9 (± 0.1). Overall magnitude of reduced lung functions was 40.1%, and the prevalence of reduced FVC, FEV1, and FEV1/FVC were 36.7, 34.3 and 3.9% respectively. The current working at twisting department, > 5 years of service duration, respiratory symptoms and increased respirable dust exposure were associated with reduction in FVC and FEV1.ConclusionsThe current working department, service duration, respiratory symptoms and exposure to respirable dust were predictors of lung functions in textile workers. An adequate ventilation, good work practices, hygienic workplace, safety and health training regarding potential health effects, and periodically assessment of lung functions are the critical elements for control of respirable dust exposure and reduction of occupational lung diseases.

Tolerability of individual chemotherapy regimens in children suffering from respiratory tuberculosis and exposed to multiple and extensive drug resistant tuberculosis

The objective of the study: to assess the tolerability of anti-tuberculosis drugs (TB drugs) in children with respiratory tuberculosis and exposure to multiple and extensive drug resistant tuberculosis treated by individual chemotherapy (CT) regimens.Subjects and methods: Totally, 89 children (2-12 years old) with respiratory tuberculosis, they all were exposed to multiple and extensive drug resistant tuberculosis. Patients were divided into three groups: Group 1 (17 patients) – minor forms, the chemotherapy regimen consisted of 3 TB drugs, Group 2 (35 patients) – limited lesions, the chemotherapy regimen consisted of 4 TB drugs, Group 3 (37 patients) – the disseminated disease, the chemotherapy regimen consisted of 5 TB drugs. The following TB drugs were used in Group 1: Pto ‒ in 94.1%, Z ‒ in 76.5%, PAS ‒ in 76.5%, Am – in 35.3%, E – in 17.6%, and Cs – in 5.9% of cases. In Group 2: PAS – in 94.3%, Z – in 80.0%, Pto – in 68.6%, Am – in 48.6% and Fq – in 45.7%, Cs ‒ in 37.1%, and E – in 25.7% of cases. In Group 3: Z – in 97.3%, PAS – in 89.2%, Pto – in 81.1%, Fq ‒ in 73.0%, Am – in 70.3%, Cs – in 51.4%, and E – in 37.8% of cases.Results. In general, chemotherapy was well tolerated by 50.6% (45 people) of children, and poorly - by 49.4% (44 people), p> 0.05. Toxic reactions were observed statistically significantly more often versus allergic ones: 63.6 ± 7.3% (28 persons) and 36.4 ± 7.3% (16 persons), p < 0.05. The culprits drugs causing toxic reactions were prothionamide (24 patients), pyrazinamide (2 patients), cycloserine (1 patients), and levofloxacin (1 patients), toxic reactions - amikacin (16 patients). Adverse reactions statistically significantly more often occurred when five-component regimen (67.6 ± 7.7%) was used versus three- and four-component regimens (29.4 ± 11.4 and 40.0 ± 8.3%, respectively), p <0.05.

Effectiveness of Personal Protective Equipment in Reducing Skin Exposure to Soluble Platinum

Various forms of personal protective equipment (PPE), including disposable coveralls and gloves, are used to help reduce skin exposure to soluble platinum in precious metals refineries. We aimed to investigate the effectiveness of PPE in reducing workers' skin exposure to soluble platinum. Thirty precious metals refinery workers were divided into two groups according to their use of PPE and related procedures. Group A (n = 13) used disposable coveralls worn over standard overalls along with long-sleeved rubber gloves, while Group B (n = 17) used standard overalls only and surgical nitrile gloves. The skin (palm, wrist, neck, and forehead) and respiratory exposure of these groups to soluble platinum were concurrently measured (using Ghostwipes™ and MDHS 46/2, respectively) along with their urinary platinum excretion. Both groups of workers experienced comparable geometric mean (GM) respiratory exposure to soluble platinum (Group A = 0.744 µg m-3 versus Group B = 0.711 µg m-3) (P = 0.789), but significantly lower skin exposure (average of all measured anatomical areas) was found for Group A (Group A = 0.005 µg cm-2 versus Group B = 0.033 µg cm-2) (P = 0.018). Significantly lower skin exposure was measured on the palm (P = 0.017), wrist (P = 0.017), forehead (P = 0.027) of Group A workers compared with Group B. No significant difference was found for the urinary platinum excretion of the two groups (Group A GM = 0.208 µg g-1 creatinine versus Group B GM = 0.361 µg g-1 creatinine) (P = 0.273). The use of disposable coveralls and long-sleeved rubber gloves, along with strict usage procedures, proved effective in reducing precious metals refinery workers' skin exposure to soluble platinum.

Assessment of respiratory exposure to cypermethrin among farmers and farm workers of Shiraz, Iran.

Cypermethrin, a member of the synthetic pyrethroids group, is a popular insecticide used to eliminate a broad range of common bugs in agricultural lands and households. However, studies of farmers' exposure to this insecticide are limited. The present study aimed to measure the respiratory exposure to cypermethrin among farmers and farm workers of Shiraz, as one of the biggest cities in Fars province, Iran. Totally, nine target regions were selected, where 42 individual samples were taken using XAD-2 sorbents and were analyzed by gas chromatography-electron capture detector (GC-ECD). This is the first study on farmers' exposure to insecticides during spraying in Iran. The average concentration of cypermethrin vapor in farmers' respiratory area during spraying was 0.982 ± 0.421mg/m3, which was lower than the permitted threshold value for cypermethrin recommended by the Occupational Safety and Health Administration (OSHA). The mean time-weighted average (TWA) was also evaluated in two distinct occupational groups (tree operators and field operators). The exposure was significantly higher in tree operators than in field operators. A direct correlation was also found between the height of the workers and the amount of cypermethrin (Spearman's r = 0.555). Findings support that farm workers' respiratory exposure to cypermethrin was within the permissible range, but this situation cannot guarantee workers' safety. Total respiratory exposure and skin exposure studies are recommended in future research.

O037 / #606: NON-INVASIVE VENTILATION PRACTICE FOR PRIMARY RESPIRATORY MANAGEMENT IN THE PEDIATRIC INTENSIVE CARE UNITS: AN INTERNATIONAL STUDY

Aims & Objectives: To describe current practices and outcomes of Non-Invasive Ventilation (NIV) in PICUs internationally. Methods: IRB approved point prevalence study over 10 study weeks at 52 PICUs in 12 countries. Children were included if NIV was newly initiated on screening days, including high flow nasal cannula [HFNC: > 3LPM (Term / <1 year), > 4LPM (1-3 years), or >5LPM (>3 years)], continuous (CPAP) or bilevel positive airway pressure (BiPAP), or other NIV mode. We excluded post-operative cardiac surgery, post-extubation, and home NIV. The risk factor analysis used mixed effects logistic regression with stepwise addition/deletion (retention cutoff: p=0.15) Results: Of 15,310 patients screened, 695 met inclusion criteria, including 472 (68%) HFNC, 158 (23%) BiPAP, 62 (9%) CPAP, and 3 other modes. Median age was 15.4 months (IQR: 5.1-63.3). Main NIV indications were acute hypoxemia (51%) and respiratory distress (27%). NIV interface was nasal cannula 399 (58%), nasal mask/prongs 111 (16%), bucco-nasal mask 18 (3%), full-face mask 154 (22%), or other 3 (0.4%). NIV duration was 2.1 days (1-4). NIV failure (endotracheal intubation) occurred in 18.6% cases, 69.8% of them before 48h of NIV (Figure). After adjustment for severity of illness, risk factors for NIV failure included meeting at-risk criteria for Pediatric Acute Respiratory Distress Syndrome (p=0.02) and exposure to parenteral nutrition (p=<0.001). Factors predictive of NIV success were respiratory admission category (p=0.001) and exposure to enteral nutrition (p=0.001).Conclusions: NIV is frequently used in PICUs, with heterogenous practice. NIV failure occurs in 18.6% cases, most frequently within the first 48hrs

Etiologies of Rheumatoid Arthritis: Update on Mucosal, Genetic, and Cellular Pathogenesis.

Purpose of ReviewOver the last few years, the scientific community has made significant progress in understanding the etiology of rheumatoid arthritis (RA). In this review, we summarize those key findings and trends.Recent FindingsNew data strongly implicates respiratory exposures, obesity, diet and microbiome, genetics, and their interactions in the etiology of RA. Furthermore, anti-posttranslationally modified protein antibodies (AMPAs) and abnormal glycosylation may be additional biomarkers for RA. Finally, functional genomics techniques implicate loss of certain macrophage populations and proliferation of synovial fibroblasts in RA.SummaryThese findings support the notion that RA originates at mucosal sites, augmented by genetic predisposition, and mediated by certain cell types including macrophages and fibroblasts. Weight loss, physical activity, and diet are additional modifiable factors beyond smoking cessation that can reduce risk of RA. Future epidemiologic and translational studies leveraging multi-omics approaches will help map the precise sequence of events in RA pathogenesis.