Micronucleus frequency in children exposed to biomass burning in the Brazilian Legal Amazon region: a control case study

<p>Abstract</p> <p>Background</p> <p>The Amazon represents an area of 61% of Brazilian territory and is undergoing major changes resulting from disorderly economic development, especially the advance of agribusiness. Composition of the atmosphere is controlled by several natural and anthropogenic processes, and emission from biomass burning is one with the major impact on human health. The aim of this study was to evaluate genotoxic potential of air pollutants generated by biomass burning through micronucleus assay in exfoliated buccal cells of schoolchildren in the Brazilian Amazon region.</p> <p>Methods</p> <p>The study was conducted during the dry seasons in two regions of the Brazilian Amazon. The assay was carried out on buccal epithelial cells of 574 schoolchildren between 6-16 years old.</p> <p>Results</p> <p>The results show a significant difference between micronucleus frequencies in children exposed to biomass burning compared to those in a control area.</p> <p>Conclusions</p> <p>The present study demonstrated that in situ biomonitoring using a sensitive and low cost assay (buccal micronucleus assay) may be an important tool for monitoring air quality in remote regions. It is difficult to attribute the increase in micronuclei frequency observed in our study to any specific toxic element integrated in the particulate matters. However, the contribution of the present study lies in the evidence that increased exposure to fine particulate matter generates an increased micronuclei frequency in oral epithelial cells of schoolchildren.</p

Sidestream cigarette smoke effects on cardiovascular responses in conscious rats: involvement of oxidative stress in the fourth cerebral ventricle

Background: Cigarette exposure increases brain oxidative stress. The literature showed that increased brain oxidative stress affects cardiovascular regulation. However, no previous study investigated the involvement of brain oxidative stress in animals exposed to cigarette and its relationship with cardiovascular regulation. We aimed to evaluate the effects of central catalase inhibition on baroreflex and cardiovascular responses in rats exposed to sidestream cigarette smoke (SSCS). Methods: We evaluated males Wistar rats (320-370 g), which were implanted with a stainless steel guide cannula into the fourth cerebral ventricle (4th V). Femoral artery and vein were cannulated for mean arterial pressure (MAP) and heart rate (HR) measurement and drug infusion, respectively. Rats were exposed to SSCS during three weeks, 180 minutes, 5 days/week (CO: 100-300 ppm). Baroreflex was tested with a pressor dose of phenylephrine (PHE, 8 mu g/kg, bolus) to induce bradycardic reflex and a depressor dose of sodium nitroprusside (SNP, 50 mu g/kg, bolus) to induce tachycardic reflex. Cardiovascular responses were evaluated before, 5, 15, 30 and 60 minutes after 3-amino-1,2,4-triazole (ATZ, catalase inhibitor, 0.001 g/100 mu L) injection into the 4th V. Results: Central catalase inhibition increased basal HR in the control group during the first 5 minutes. SSCS exposure increased basal HR and attenuated bradycardic peak during the first 15 minutes. Conclusion: We suggest that SSCS exposure affects cardiovascular regulation through its influence on catalase activity.Foundation of Support to Research of Sao Paulo State (Fundacao de Amparo a Pesquisa do Estado de Sao Paulo-FAPESP [07/59127-9

Joint effect of heat and air pollution on mortality in 620 cities of 36 countries

Background The epidemiological evidence on the interaction between heat and ambient air pollution on mortality is still inconsistent. Objectives To investigate the interaction between heat and ambient air pollution on daily mortality in a large dataset of 620 cities from 36 countries. Methods We used daily data on all-cause mortality, air temperature, particulate matter ≤ 10 μm (PM10), PM ≤ 2.5 μm (PM2.5), nitrogen dioxide (NO2), and ozone (O3) from 620 cities in 36 countries in the period 1995–2020. We restricted the analysis to the six consecutive warmest months in each city. City-specific data were analysed with over-dispersed Poisson regression models, followed by a multilevel random-effects meta-analysis. The joint association between air temperature and air pollutants was modelled with product terms between non-linear functions for air temperature and linear functions for air pollutants. Results We analyzed 22,630,598 deaths. An increase in mean temperature from the 75th to the 99th percentile of city-specific distributions was associated with an average 8.9 % (95 % confidence interval: 7.1 %, 10.7 %) mortality increment, ranging between 5.3 % (3.8 %, 6.9 %) and 12.8 % (8.7 %, 17.0 %), when daily PM10 was equal to 10 or 90 μg/m3, respectively. Corresponding estimates when daily O3 concentrations were 40 or 160 μg/m3 were 2.9 % (1.1 %, 4.7 %) and 12.5 % (6.9 %, 18.5 %), respectively. Similarly, a 10 μg/m3 increment in PM10 was associated with a 0.54 % (0.10 %, 0.98 %) and 1.21 % (0.69 %, 1.72 %) increase in mortality when daily air temperature was set to the 1st and 99th city-specific percentiles, respectively. Corresponding mortality estimate for O3 across these temperature percentiles were 0.00 % (-0.44 %, 0.44 %) and 0.53 % (0.38 %, 0.68 %). Similar effect modification results, although slightly weaker, were found for PM2.5 and NO2. Conclusions Suggestive evidence of effect modification between air temperature and air pollutants on mortality during the warm period was found in a global dataset of 620 cities.Massimo Stafoggia, Francesca K. de’ Donato, Masna Rai and Alexandra Schneider were partially supported by the European Union’s Horizon 2020 Project Exhaustion (Grant ID: 820655). Jan Kyselý and Aleš Urban were supported by the Czech Science Foundation project (22-24920S). Joana Madureira was supported by the Fundação para a Ciência e a Tecnologia (FCT) (grant SFRH/BPD/115112/2016). Masahiro Hashizume was supported by the Japan Science and Technology Agency (JST) as part of SICORP, Grant Number JPMJSC20E4. Noah Scovronick was supported by the NIEHS-funded HERCULES Center (P30ES019776). South African Data were provided by Statistics South Africa, which did not have any role in conducting the study. Antonio Gasparrini was supported by the Medical Research Council-UK (Grants ID: MR/V034162/1 and MR/R013349/1), the Natural Environment Research Council UK (Grant ID: NE/R009384/1), and the European Union’s Horizon 2020 Project Exhaustion (Grant ID: 820655)

Genotoxic potential generated by biomass burning in the Brazilian Legal Amazon by Tradescantia micronucleus bioassay: a toxicity assessment study

<p>Abstract</p> <p>Background</p> <p>The Brazilian Amazon has suffered impacts from non-sustainable economic development, especially owing to the expansion of agricultural commodities into forest areas. The Tangará da Serra region, located in the southern of the Legal Amazon, is characterized by non-mechanized sugar cane production. In addition, it lies on the dispersion path of the pollution plume generated by biomass burning. The aim of this study was to assess the genotoxic potential of the atmosphere in the Tangará da Serra region, using <it>Tradescantia pallida </it>as <it>in situ </it>bioindicator.</p> <p>Methods</p> <p>The study was conducted during the dry and rainy seasons, where the plants were exposed to two types of exposure, active and passive.</p> <p>Results</p> <p>The results showed that in all the sampling seasons, irrespective of exposure type, there was an increase in micronucleus frequency, compared to control and that it was statistically significant in the dry season. A strong and significant relationship was also observed between the increase in micronucleus incidence and the rise in fine particulate matter, and hospital morbidity from respiratory diseases in children.</p> <p>Conclusions</p> <p>Based on the results, we demonstrated that pollutants generated by biomass burning in the Brazilian Amazon can induce genetic damage in test plants that was more prominent during dry season, and correlated with the level of particulates and elevated respiratory morbidity.</p

Variations of respiratory mechanics in the rat during the day

We applied the end-inflation occlusion method to measure resistive and elastic properties of the rat's respiratory system at two different hours of the day, 8.00 a.m. and 4.00 p.m. Contextually lung hysteresis surface areas were also measured. We found a significant reduction of resistive pressure necessary for the movement of air in the airways and for the movement of lung and chest wall tissue, hence of respiratory and lung resistances, in the afternoon with respect to morning hours (Rrs, min 0.037 vs 0.117 cm H(2)O/ml sec(-1), p = 0.008, Rl, min 0.021 vs 0.068 cm H(2)O/ml sec(-1), p = 0.001). The areas of hysteresis were significantly higher in the afternoon compared to the morning (3.71 vs 2.51 cm H(2)Oml, p = 0.039). No other significant differences in respiratory mechanical parameters were found. Thus we show in the rat that airways and lung and chest wall resistances exhibit variations during the day, confirming previously reported data describing a circadian rhythm of resistance in other animal species. Hysteretic behaviour of the lungs also changes during the day, suggesting diurnal variations of alveolar surfactant activity

Queima de biomassa e efeitos sobre a saúde Biomass burning and its effects on health

A primeira idéia que se forma na mente das pessoas e do pesquisador é associar a poluição do ar aos grandes centros urbanos, com a imagem de poluentes sendo eliminados por veículos automotores ou pela chaminé de suas fábricas. Entretanto, uma parcela considerável da população do planeta convive com uma outra fonte de poluição, que atinge preferencialmente os países em desenvolvimento: a queima de biomassa. Este artigo tem como objetivo chamar a atenção do pneumologista, da comunidade e das autoridades para os riscos à saúde da população exposta a essa fonte geradora de poluentes, seja em ambientes internos, seja em ambientes abertos. O presente trabalho caracteriza as principais condições que levam à combustão de biomassa, como a literatura tem registrado os seus efeitos sobre a saúde humana, discutindo os mecanismos fisiopatológicos envolvidos, e finaliza com a apresentação de dois estudos recentes que enfatizam a importância da queima de um tipo específico de biomassa, a palha da cana-de-açúcar, prática comum no interior do Brasil, e sua interferência no perfil de morbidade respiratória da população exposta.<br>The first thought that comes to mind concerning air pollution is related to urban centers where automotive exhausts and the industrial chimneys are the most important sources of atmospheric pollutants. However a significant portion of the earth’s population is exposed to still another source of air pollution, the burning of biomass that primarily affects developing countries. This review article calls the attention of lung specialists, public authorities and the community in general to the health risks entailed in the burning of biomass, be it indoors or outdoors to which the population is exposed. This review describes the main conditions that lead to the burning of biomass and how the literature has recorded its effects on human health discussing the psychopathological mechanisms. Finally two recent studies are presented that emphasize an important type of biomass burning that of the sugar cane straw. This is a common practice in several regions of Brazil changing the respiratory morbidity standards of the population exposed