Assessment of the Oxidative Potential and Oxidative Burden from Occupational Exposures to Particulate Matter.

Oxidative potential (OP) is a toxicologically relevant metric that integrates features like mass concentration and chemical composition of particulate matter (PM). Although it has been extensively explored as a metric for the characterization of environmental particles, this is still an underexplored application in the occupational field. This study aimed to estimate the OP of particles in two occupational settings from a construction trades school. This characterization also includes the comparison between activities, sampling strategies, and size fractions. Particulate mass concentrations (PM4-Personal, PM4-Area, and PM2.5-Area) and number concentrations were measured during three weeks of welding and construction/bricklaying activities. The OP was assessed by the ascorbate assay (OPAA) using a synthetic respiratory tract lining fluid (RTLF), while the oxidative burden (OBAA) was determined by multiplying the OPAA values with PM concentrations. Median (25th-75th percentiles) of PM mass and number concentrations were 900 (672-1730) µg m-3 and 128 000 (78 000-169 000) particles cm-3 for welding, and 432 (345-530) µg m-3 and 2800 (1700-4400) particles cm-3 for construction. Welding particles, especially from the first week of activities, were also associated with higher redox activity (OPAA: 3.3 (2.3-4.6) ρmol min-1 µg-1; OBAA: 1750 (893-4560) ρmol min-1 m-3) compared to the construction site (OPAA: 1.4 (1.0-1.8) ρmol min-1 µg-1; OBAA: 486 (341-695) ρmol min-1 m-3). The OPAA was independent of the sampling strategy or size fraction. However, driven by the higher PM concentrations, the OBAA from personal samples was higher compared to area samples in the welding shop, suggesting an influence of the sampling strategy on PM concentrations and OBAA. These results demonstrate that important levels of OPAA can be found in occupational settings, especially during welding activities. Furthermore, the OBAA found in both workplaces largely exceeded the levels found in environmental studies. Therefore, measures of OP and OB could be further explored as metrics for exposure assessment to occupational PM, as well as for associations with cardiorespiratory outcomes in future occupational epidemiological studies.

Indoor concentrations of particulate matter 2.5 in a pediatric emergency service / Concentrações indoor de material particulado 2,5 em Serviço de Emergência Pediátrica

Abstract Objective: To evaluate air quality in the waiting room of a pediatric emergency service considering the serial concentrations of particulate matter (PM2.5), and to determine if the number of people present in the room can have an influence on the pollutant concentrations. Methods: Cross-sectional study, carried out in the waiting room of a reference pediatric hospital in the city of Porto Alegre, conducted in a one-year period, in a continuous-time sample including all of the four seasons of the year. The monitoring of PM2.5 was performed using a real-time aerosol monitor (DustTrak II). The number of people in the room was determined every hour and the climatic characteristics per daily mean. The concentration of PM2.5 and the number of people were expressed by mean and standard deviation. The means were compared by Analysis of Variance and Pearson's correlation coefficient. Results: There was a significant increase in the concentration of PM2.5 in the autumn, when compared to other seasons (p<0.001). The pollutant increase, in this season, was accompanied by the higher number of people in the emergency room (p=0.026). The association between PM2.5 and the number of people is confirmed by the positive correlation between these two variables (r=0.738; p<0.001). Conclusions: The pediatric emergency waiting room showed elevated PM2.5 in all seasons. The number of people in the room had a positive correlation with the concentration of the pollutant in the environment.

Resumo Objetivo: Avaliar a qualidade do ar na sala de espera de um serviço de emergência pediátrica pelas concentrações ambientais seriadas de material particulado (MP2,5) e determinar se o número de pessoas presentes no ambiente influencia as concentrações do poluente. Métodos: Estudo transversal, realizado na sala de espera de um hospital pediátrico de referência na cidade de Porto Alegre, conduzido ao longo de um ano, com um período de amostragem temporal contínua com duração de uma semana, em todas as quatro estações do ano. O monitoramento do MP2,5 foi realizado por meio de um monitor de aerossol em tempo real (DustTrak II). O número de pessoas no ambiente foi determinado a cada hora e as características climáticas por média diária. As concentrações de MP2,5 e o número de pessoas foram expressos por médias e desvio padrão. As médias foram comparadas por análise de variância e pelo coeficiente de correlação de Pearson. Resultados: Houve aumento significativo na concentração do MP2,5 no outono, quando comparado com as outras estações (p<0,001). O aumento desse poluente, nessa estação, esteve acompanhado de maior número de pessoas na emergência (p=0,026). A associação entre MP2,5 e número de pessoas é ratificado pela correlação positiva entre essas duas variáveis (r=0,738; p<0,001). Conclusões: A sala de espera da emergência pediátrica apresentou concentrações elevadas de MP2,5 durante todas as estações do ano. O número de pessoas no ambiente guardou correlação positiva com as concentrações do poluente no ambiente.

Indoor concentrations of particulate matter 2.5 in a pediatric emergency service.

OBJECTIVE: To evaluate air quality in the waiting room of a pediatric emergency service considering the serial concentrations of particulate matter (PM2.5), and to determine if the number of people present in the room can have an influence on the pollutant concentrations. METHODS: Cross-sectional study, carried out in the waiting room of a reference pediatric hospital in the city of Porto Alegre, conducted in a one-year period, in a continuous-time sample including all of the four seasons of the year. The monitoring of PM2.5 was performed using a real-time aerosol monitor (DustTrak II). The number of people in the room was determined every hour and the climatic characteristics per daily mean. The concentration of PM2.5 and the number of people were expressed by mean and standard deviation. The means were compared by Analysis of Variance and Pearson's correlation coefficient. RESULTS: There was a significant increase in the concentration of PM2.5 in the autumn, when compared to other seasons (p<0.001). The pollutant increase, in this season, was accompanied by the higher number of people in the emergency room (p=0.026). The association between PM2.5 and the number of people is confirmed by the positive correlation between these two variables (r=0.738; p<0.001). CONCLUSIONS: The pediatric emergency waiting room showed elevated PM2.5 in all seasons. The number of people in the room had a positive correlation with the concentration of the pollutant in the environment.

Micronucleus count in nasal epithelial cells from patients with chronic rhinosinusitis and polyps / Contagem de micronúcleos em células epiteliais nasais de pacientes com rinossinusite crônica e pólipos

Abstract Introduction: Chronic rhinosinusitis with nasal polyps, a prevalent disease affecting around 2% of the world population, is characterized by symptomatic inflammation of the nasal mucosa and impairment of quality of life. Chronic rhinosinusitis with nasal polyps has a multifactorial etiology, involving a dysfunctional host response to environmental factors. Thus, inflammatory models may be useful to shed light on the pathophysiology of this disease. Micronucleus count has been used to screen DNA damage in various tissues. Objective: To investigate the association between frequency of micronucleus in exfoliated cells from the nasal cavity of patients with chronic rhinosinusitis with nasal polyps and disease severity. Methods: This cross-sectional study included 21 patients with chronic rhinosinusitis with nasal polyps and 19 controls without disease. None of the participants were smokers. Results: Mean micronucleus count was 3.690 per 1000 cells (±2.165) in individuals with vs. 1.237 per 1000 cells (±0.806) in controls; (Student's t test = 4.653, p< 0.001). Nasal surgery in the past 5 years and aspirin-exacerbated respiratory disease were not associated with nicronucleus count (p= 0.251). Conclusion: Micronucleus count seems to be linked to chronic rhinosinusitis with nasal polyps, providing a new perspective for the evaluation of this disorder.

Resumo Introdução: A rinossinusite crônica com pólipos nasais, doença prevalente que afeta cerca de 2% da população mundial, é caracterizada por inflamação sintomática da mucosa nasal e comprometimento da qualidade de vida. A rinossinusite crônica com pólipos nasais tem etiologia multifatorial, envolvendo resposta disfuncional do hospedeiro a fatores ambientais. Assim, modelos inflamatórios podem ser úteis para esclarecer a fisiopatologia dessa doença. A contagem de micronúcleos tem sido usada para rastrear danos no DNA em vários tecidos. Objetivo: Investigar a associação entre a frequência de micronúcleos em células esfoliadas da cavidade nasal de pacientes com rinossinusite crônica com pólipos nasais e a gravidade da doença. Método: Estudo transversal que incluiu 21 pacientes com rinossinusite crônica com pólipos nasais e 19 controles sem doença. Nenhum dos participantes era fumante. Resultados: A contagem média de micronúcleos foi de 3,690 por 1.000 células (± 2,165) nos indivíduos doentes e 1,237 por 1.000 células (± 0,806) nos controles (teste t de Student = 4,653; p < 0,001). A cirurgia nasal nos últimos 5 anos e a doença respiratória exacerbada por aspirina não foram associadas à contagem de micronúcleos (p = 0,251). Conclusão: A contagem de micronúcleos parece estar ligada à rinossinusite crônica com pólipos nasais, proporcionando uma nova perspectiva para a avaliação dessa doença.

Micronucleus count in nasal epithelial cells from patients with chronic rhinosinusitis and polyps.

INTRODUCTION: Chronic rhinosinusitis with nasal polyps, a prevalent disease affecting around 2% of the world population, is characterized by symptomatic inflammation of the nasal mucosa and impairment of quality of life. Chronic rhinosinusitis with nasal polyps has a multifactorial etiology, involving a dysfunctional host response to environmental factors. Thus, inflammatory models may be useful to shed light on the pathophysiology of this disease. Micronucleus count has been used to screen DNA damage in various tissues. OBJECTIVE: To investigate the association between frequency of micronucleus in exfoliated cells from the nasal cavity of patients with chronic rhinosinusitis with nasal polyps and disease severity. METHODS: This cross-sectional study included 21 patients with chronic rhinosinusitis with nasal polyps and 19 controls without disease. None of the participants were smokers. RESULTS: Mean micronucleus count was 3.690 per 1000 cells (±2.165) in individuals with vs. 1.237 per 1000 cells (±0.806) in controls; (Student's t test = 4.653, p < 0.001). Nasal surgery in the past 5 years and aspirin-exacerbated respiratory disease were not associated with nicronucleus count (p = 0.251). CONCLUSION: Micronucleus count seems to be linked to chronic rhinosinusitis with nasal polyps, providing a new perspective for the evaluation of this disorder.

Direct contact with particulate matter increases oxidative stress in different brain structures.

INTRODUCTION: Several experimental and epidemiological studies have demonstrated the neurological adverse effects caused by exposure to air pollution, specifically in relation to pollutant particulate matter (PM). The objective of this study was to investigate the direct effect of PM in increased concentrations in different brain regions, as well as the mechanisms involving its neurotoxicity, by evaluating oxidative stress parameters in vitro. METHODS: Olfactory bulb, cerebral cortex, striatum, hippocampus and cerebellum of rats were homogenized and incubated with PM < 2.5 µm of diameter (PM2.5) at concentrations of 3, 5 and 10 µg/mg of tissue. The oxidative damage caused by lipid peroxidation of these structures was determined by testing the thiobarbituric acid reactive species (TBA-RS). In addition, we measured the activity of antioxidant enzyme catalase (CAT) and superoxide dismutase (SOD). RESULTS: All PM concentrations were able to damage the cerebellum and hippocampus, strongly enhancing the lipid peroxidation in both structures. PM incubation also decreased the CAT activity of the hippocampus, cerebellum, striatum and olfactory bulb, though it did not generate higher levels of lipid peroxidation in either of the last two structures. PM incubation did not alter any measurement of the cerebral cortex. CONCLUSION: The cerebellum and hippocampus seem to be more susceptible than other brain structures to in vitro direct PM exposure assay and the oxidative stress pathway catalyzes the neurotoxic effect of PM exposure, as evidenced by high consumption of CAT and high levels of TBA-RS. Thus, PM direct exposure seems to activate toxic neurological effects.

A comparison of the human buccal cell assay and the pollen abortion assay in assessing genotoxicity in an urban-rural gradient.

Air pollution is exacerbated near heavy traffic roads in cities. Air pollution concentration and composition vary by region and depend on urban-rural gradients. The aim of this study was to evaluate the distribution of air pollution in areas of varying population densities and to compare plant biomonitoring with an established biomarker of human exposure to traffic-related air pollution in children. The areas of study were selected near a major street in 3 different regions. Areas A, B and C represent high, intermediate and low population densities, respectively. Micronucleus assay, an established biomarker of human exposure, was performed in children from these areas. For a plant biomonitoring assay, the pollen abortion assay was performed on Bauhinia variegata in these areas. NO2 and O3 concentrations were determined by passive sampling. We report here that the pollen abortion frequency in Bauhinia variegata is correlated with NO2 concentration (P = 0.004) and is strongly associated with vehicular flow and population density in the studied areas. Micronuclei frequency in buccal cells of children was higher in the regions with more degree of urbanization (P < 0.001) following the same pattern of O3 concentrations (P = 0.030). In conclusion, our results demonstrate that high concentrations of air pollutants in Porto Alegre are related to both human and plant genotoxicity. Areas with different concentration of pollutants demonstrated to have an urbanization gradient dependent pattern which also reflected on genotoxic damage among these areas.

Trace elements concentration in nails and association with airway inflammation in adolescents.

Asthma is a multifactorial disease and its severity varies with the inflammatory status of the patient. It has been hypothesized that deficiency of trace elements has an important role in the etiology of asthma. The aim of the study was to evaluate the concentration of trace elements in nails of adolescents with different degrees of airway inflammation. We assessed the prevalence of active and severe asthma in adolescents (n = 106) through the ISAAC questionnaire. Subjects were allocated into two different groups according to the value of fraction exhaled nitric oxide (FeNO) measured. Also, nail specimens were collected in order to determine the concentration of accumulated trace elements (Cu, Zn, Mn, Se) by ICP-MS. It was performed Student's t test to evaluate statistical differences between inflammatory groups considering normally distributed data. On the other hand, when data presented non-normal distribution, Mann-Whitney U test was utilized. Spearman coefficients were calculated to investigate correlations between FeNO and mineral concentrations. Exhaled NO was increased in male subjects. We found association between active asthma and elevated exhaled NO. There was no significant difference in Cu (4.40 vs. 4.52), Zn (84.66 vs. 79.48), Mn (0.59 vs. 0.76), and Se (0.18 vs. 0.19) concentrations (µg/g) among distinct FeNO groups as well as was not observed correlation between exhaled NO levels and any element. Deficiency of trace elements in nails were not associated with increased FeNO.