Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 25
Filtrar
Más filtros










Intervalo de año de publicación
1.
Sci Rep ; 12(1): 11083, 2022 06 30.
Artículo en Inglés | MEDLINE | ID: mdl-35773451

RESUMEN

Heavy metals are natural and essential elements of the environment and living beings, produced from natural (e.g. volcanic activity and cosmic ray-induced spallation) and anthropogenic processes (e.g. industrial and fossil fuel combustion). High-concentrations of heavy metals and radionuclides are also originated from anthropogenic activities in urban and industrial areas. In this preliminary study, we analyzed the levels of heavy metals and Polonium-210 (210Po) in lung tissues in autopsies from residents of the city of Sao Paulo, SP, Brazil. In order to identify the link among sources of the heavy metals in lungs, factor analysis was performed. Of the first four factors, which explain 66% of the total variability, three were associated with vehicular sources. The fitting of a regression model with 210Po as the response variable and with the four factors as explanatory variables, controlling for age, sex and tobacco, showed a significant association between the concentration of polonium and the first factor that is generated by catalysts and brakes (coefficient = 0.90, standard error = 0.33, p = 0.016). Our findings suggest an association between traffic-related trace metals and 210Po in lung autopsies.


Asunto(s)
Contaminación del Aire , Metales Pesados , Oligoelementos , Contaminación del Aire/análisis , Brasil , Ciudades , Monitoreo del Ambiente , Pulmón/química , Metales Pesados/análisis , Oligoelementos/análisis
2.
Bull Environ Contam Toxicol ; 107(1): 29-36, 2021 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-33877373

RESUMEN

The control of air pollution remains a challenge to the planning of cities and fossil fuel burning is the main cause of air degradation. Particulate matter (PM) is the contaminant commonly used as an indicator of pollution, but environmental agencies may face difficulties in operating surveillance networks due to the lack of resources and infrastructure. As an alternative to conventional networks, scientific studies have pointed out that nature itself can contribute to the diagnosis and reduction of air pollution. Nature-based solutions (NbS) are proposals that use natural processes and structures to meet different environmental challenges. In this study, biomonitoring with Tillandsia usneoides was applied as a NbS tool to evaluate air quality in an important port urban area in the city of Guarujá, Brazil, affected by industrial and vehicular emissions. It was observed that cadmium mass fractions were at least forty times higher than the control area with one-month exposition.


Asunto(s)
Contaminantes Atmosféricos , Contaminación del Aire , Contaminantes Atmosféricos/análisis , Contaminación del Aire/análisis , Monitoreo Biológico , Brasil , Ciudades , Monitoreo del Ambiente , Material Particulado/análisis , Salud Pública
3.
Sci Rep ; 10(1): 180, 2020 01 13.
Artículo en Inglés | MEDLINE | ID: mdl-31932745

RESUMEN

The accumulation of detectable amounts of radon progeny in human tissues may be a risk factor for development and progression of chronic diseases. In this preliminary study, we analyzed the levels of alpha-emitting radon progeny Polonium-210 (210Po) in the olfactory epithelium, olfactory bulb, frontal lobe, and lung tissues in cadavers from the city of Sao Paulo, SP, Brazil. We also assessed the association between 210Po levels and exposure parameters for urban air pollution using linear regression models adjusted for age, sex, smoke, time living in Sao Paulo, daily commuting, socioeconomic index, and anthracosis (traffic-related black carbon accumulation in the pleural region and in lymph). Our findings show that the concentration of 210Po was associated with anthracosis in lungs of non-smokers (coefficient = 6.0; standard error = 2.9; p = 0.04). Individuals with lower socioeconomic status also had significantly higher 210Po levels in lungs (coefficient = -1.19; standard error = 0.58; p = 0.042). The olfactory bulb had higher 210Po levels than either olfactory epithelium (p = 0.071), frontal lobe (p < 0.001), or lungs (p = 0.037). Our findings of the deposition of 210Po in autopsy tissues suggest that airborne radionuclides may contribute to the development of chronic diseases, including neurodegenerative diseases.


Asunto(s)
Contaminantes Radiactivos del Aire/análisis , Encéfalo/metabolismo , Pulmón/metabolismo , Polonio/análisis , Adulto , Anciano , Anciano de 80 o más Años , Autopsia , Brasil , Femenino , Humanos , Masculino , Persona de Mediana Edad , Factores de Riesgo , Adulto Joven
4.
Environ Pollut ; 263(Pt A): 114583, 2020 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-33618488

RESUMEN

Although air pollution decreased in some cities that shifted from an industrial to a service-based economy, and vehicular emission regulation became more restrictive, it is still a major risk factor for mortality worldwide. In central São Paulo, Brazil, air quality monitoring stations and tree-ring analyses revealed a decreasing trend in the concentrations of particulate matter and metals. Such trends, however, may not be observed in industrial districts located in the urban periphery, where the usual mobile sources may be combined with local stationary sources. To evaluate environmental pollution in an industrial district in southeastern São Paulo, we assessed its spatial variability, by measuring magnetic properties and concentrations of Al, Ba, Ca, Cl, Cu, Fe, K, Mg, Mn, P, S, Sr, Zn in the bark of 62 trees, and its temporal trends, by measuring Cd, Cu, Ni, Pb, V, Zn in tree rings of three trees. Source apportionment analysis based on tree barks revealed two clusters with high concentrations of metals, one related to vehicular and industrial emissions (Al, Ba, Cu, Fe, Zn) in the east side of the industrial cluster, and the other related to soil resuspension (Cu, Zn, Mn) in its west side. These patterns are also supported by the magnetic properties of bark associated with iron oxides and titanium-iron alloy concentrations. Dendrochemical analyses revealed that only the concentrations of Pb consistently decreased over the last four decades. The concentrations of Cd, Cu, Ni, V, and Zn did not significantly decrease over time, in contrast with their negative trends previously reported in central São Paulo. This combined biomonitoring approach revealed spatial clusters of metal concentration in the vicinity of this industrial cluster and showed that the local population has not benefited from the decreasing polluting metal concentrations in the last decades.


Asunto(s)
Monitoreo del Ambiente , Metales Pesados , Brasil , Ciudades , Contaminación Ambiental , Metales/análisis , Metales Pesados/análisis
6.
Sci Rep ; 8(1): 12636, 2018 08 22.
Artículo en Inglés | MEDLINE | ID: mdl-30135462

RESUMEN

Work-exacerbated asthma (WEA) is defined as preexisting asthma that worsens with exposure to irritants [e.g., chlorine (Cl2) derivatives] in the workplace. The maximum allowable concentration in the workplace of Cl2 exposure is 3 mg/ m3 (described in OSHA). We investigated in an experimental asthma model in mice the effects of a single exposure to a sodium hypochlorite dose with this allowed chlorine concentration and a tenfold higher dose. Acute chlorine exposure at 3.3 mg/m3 in the OVA-sensitized group increased eosinophils in the peribronquial infiltrate, cytokine production, nasal mucus production and the number of iNOS positive cells in the distal lung compared to only sensitized mice. The exposure to a higher dose of 33.3 mg/m3 in the OVA-sensitized group resulted in an increase in respiratory system elastance, in the total and differential numbers of inflammatory cells in bronchoalveolar lavage fluid, IL-4, IL-5, and IL-17 in the lungs, eosinophils in peribronquial infiltrate and mucus content in nasal compared to non-exposed and sensitized animals. In this asthma model, chorine exposures at an allowable dose, contributed to the potentiation of Th2 responses. The functional alterations were associated with increased iNOS and ROCK-2 activation in the distal lung.


Asunto(s)
Asma/fisiopatología , Cloro/efectos adversos , Alérgenos , Animales , Líquido del Lavado Bronquioalveolar/citología , Citocinas , Modelos Animales de Enfermedad , Eosinófilos/inmunología , Inflamación , Pulmón/inmunología , Masculino , Ratones , Ratones Endogámicos BALB C , Mucosa Nasal/efectos de los fármacos , Óxido Nítrico Sintasa de Tipo II/metabolismo , Pruebas de Función Respiratoria , Células Th2/metabolismo , Quinasas Asociadas a rho/metabolismo
7.
Nanotechnology ; 29(20): 205704, 2018 May 18.
Artículo en Inglés | MEDLINE | ID: mdl-29504515

RESUMEN

In the investigation reported in this paper a modified thermal decomposition method was developed to produce very small Er2O3 nanoparticles (NPs). Particles structure, shape and size were characterized by x-ray diffraction and transmission electron microscopy which showed that the synthesis by thermal decomposition under O2 atmosphere produced very small and monodisperse NPs, allowing the investigation of finite-size and surface effects. Results of magnetization measurements showed that the smallest particles present the highest values of susceptibility that decrease as particle size increases. Specific heat measurements indicate that the sample with the smallest NPs (diameter ∼5 nm) has a Néel temperature of 0.54 K. The local structure of particles was investigated by measurements of hyperfine interactions with perturbed angular correlation spectroscopy using 111Cd as probe nuclei replacing the cationic sites. Results showed that the relative population of sites 8b increases in both the core and surface layer of particles.

8.
Front Plant Sci ; 8: 1575, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28979271

RESUMEN

Industrialization in developing countries associated with urban growth results in a number of economic benefits, especially in small or medium-sized cities, but leads to a number of environmental and public health consequences. This problem is further aggravated when adequate infrastructure is lacking to monitor the environmental impacts left by industries and refineries. In this study, a new protocol was designed combining biomonitoring and geostatistics to evaluate the possible effects of shale industry emissions on human health and wellbeing. Futhermore, the traditional and expensive air quality method based on PM2.5 measuring was also used to validate the low-cost geostatistical approach. Chemical analysis was performed using Energy Dispersive X-ray Fluorescence Spectrometer (EDXRF) to measure inorganic elements in tree bark and shale retorted samples in São Mateus do Sul city, Southern Brazil. Fe, S, and Si were considered potential pollutants in the study area. Distribution maps of element concentrations were generated from the dataset and used to estimate the spatial behavior of Fe, S, and Si and the range from their hot spot(s), highlighting the regions sorrounding the shale refinery. This evidence was also demonstrated in the measurements of PM2.5 concentrations, which are in agreement with the information obtained from the biomonitoring and geostatistical model. Factor and descriptive analyses performed on the concentrations of tree bark contaminants suggest that Fe, S, and Si might be used as indicators of industrial emissions. The number of cases of respiratory diseases obtained from local basic health unit were used to assess a possible correlation between shale refinery emissions and cases of repiratory disease. These data are public and may be accessed on the website of the the Brazilian Ministry of Health. Significant associations were found between the health data and refinery activities. The combination of the spatial characterization of air pollution and clinical health data revealed that adverse effects were significant for individuals over 38 years of age. These results also suggest that a protocol designed to monitor urban air quality may be an effective and low-cost strategy in environmentally contaminated cities, especially in low- and middle-income countries.

9.
Sci Total Environ ; 575: 1438-1444, 2017 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-27720253

RESUMEN

Urban gardening is a growing global phenomenon with a positive impact on society. Despite several associated benefits, growing vegetables in urban gardens that are localized in highly polluted areas poses questions about the safety of the produced food. Therefore, the identification of risk factors that result in possible deleterious effects to human health is important for realizing all of the benefits to society. We evaluated the use of two biomonitoring methods in ten urban gardens of Sao Paulo city and one control site: the micronuclei frequencies for early tetrads of Tradescantia pallida (Rose) Hunt. cv. "Purpurea" Boom (hereafter, Trad-MCN) as a short-term indicator of genotoxic response and tree barks to quantify the accumulation of traffic-related chemical elements as a long-term biomarker of air pollution in urban gardens. Mature plants of Tradescantia pallida were exposed in each garden, and their inflorescences were sampled over three months. A random set of 300 early tetrads in 13 to 21 slides per garden were evaluated for micronuclei frequencies. Elemental concentrations in 428 tree barks samples from 107 different trees in the areas surrounding urban gardens were quantified using an energy dispersive X-ray fluorescence spectrometer. The frequency of Trad-MCN has a significant correlation with traffic variables and chemical elements related to road dust and tailpipe emissions deposited in tree barks. Negative associations between Trad-MCN and both the distance through traffic and the presence of vertical obstacles were observed in the community gardens. The Mn/Zn concentrations in tree barks were associated with increased Trad-MCN.


Asunto(s)
Contaminación del Aire , Ciudades , Monitoreo del Ambiente , Jardines , Contaminantes Atmosféricos , Humanos , Pruebas de Micronúcleos , Tradescantia/efectos de los fármacos , Tradescantia/genética
10.
Environ Int ; 99: 161-169, 2017 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-27866722

RESUMEN

The majority of epidemiological studies correlate the cardiorespiratory effects of air pollution exposure by considering the concentrations of pollutants measured from conventional monitoring networks. The conventional air quality monitoring methods are expensive, and their data are insufficient for providing good spatial resolution. We hypothesized that bioassays using plants could effectively determine pollutant gradients, thus helping to assess the risks associated with air pollution exposure. The study regions were determined from different prevalent respiratory death distributions in the Sao Paulo municipality. Samples of tree flower buds were collected from twelve sites in four regional districts. The genotoxic effects caused by air pollution were tested through a pollen abortion bioassay. Elements derived from vehicular traffic that accumulated in tree barks were determined using energy-dispersive X-ray fluorescence spectrometry (EDXRF). Mortality data were collected from the mortality information program of Sao Paulo City. Principal component analysis (PCA) was applied to the concentrations of elements accumulated in tree barks. Pearson correlation and exponential regression were performed considering the elements, pollen abortion rates and mortality data. PCA identified five factors, of which four represented elements related to vehicular traffic. The elements Al, S, Fe, Mn, Cu, and Zn showed a strong correlation with mortality rates (R2>0.87) and pollen abortion rates (R2>0.82). These results demonstrate that tree barks and pollen abortion rates allow for correlations between vehicular traffic emissions and associated outcomes such as genotoxic effects and mortality data.


Asunto(s)
Contaminantes Atmosféricos/análisis , Monitoreo del Ambiente/métodos , Neoplasias Pulmonares/mortalidad , Corteza de la Planta/química , Polen/química , Enfermedad Pulmonar Obstructiva Crónica/mortalidad , Emisiones de Vehículos/análisis , Anciano , Anciano de 80 o más Años , Brasil/epidemiología , Humanos , Neoplasias Pulmonares/inducido químicamente , Persona de Mediana Edad , Enfermedad Pulmonar Obstructiva Crónica/inducido químicamente
11.
Environ Pollut ; 216: 125-134, 2016 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-27249450

RESUMEN

Although urban horticulture provides multiple benefits to society, the extent to which these vegetables are contaminated by the absorption of chemical elements derived from atmospheric deposition is unclear. This study was designed to evaluate the influence of air pollution on leafy vegetables in community gardens of Sao Paulo, Brazil. Vegetable seedlings of Brassica oleracea var. acephala (collard greens) and Spinacia oleracea (spinach) obtained in a non-polluted rural area and growing in vessels containing standard uncontaminated soil were exposed for three consecutive periods of 30, 60 and 90 days in 10 community gardens in Sao Paulo and in one control site. The concentrations of 17 chemical elements (traffic-related elements and those essential to plant biology) were quantified by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Tillandsia usneoides L. specimens were used as air plant biomonitors. The concentrations of As, Cd, Cr and Pb found in vegetables were compared to the recommended values for consumption. Principal Component Analysis (PCA) was used to cluster the elemental concentrations, and Generalized Linear Models (GLMs) were employed to evaluate the association of the factor scores from each PCA component with variables such as local weather, traffic burden and vertical barriers adjacent to the gardens. We found significant differences in the elemental concentrations of the vegetables in the different community gardens. These differences were related to the overall traffic burden, vertical obstacles and local weather. The Pb and Cd concentrations in both vegetables exceeded the limit values for consumption after 60 days of exposure. A strong correlation was observed between the concentration of traffic-related elements in vegetables and in Tillandsia usneoides L. An exposure response was observed between traffic burden and traffic-derived particles absorbed in the vegetables. Traffic-derived air pollution directly influences the absorption of chemical elements in leafy vegetables, and the levels of these elements may exceed the recommended values for consumption.


Asunto(s)
Jardines , Metales Pesados/análisis , Tillandsia/química , Verduras/química , Brassica/química , Brassica/metabolismo , Brasil , Ciudades , Monitoreo del Ambiente , Contaminación Ambiental/análisis , Modelos Lineales , Espectrometría de Masas , Metales Pesados/metabolismo , Análisis de Componente Principal , Suelo/química , Spinacia oleracea/química , Spinacia oleracea/metabolismo , Tillandsia/metabolismo , Verduras/metabolismo
12.
Environ Int ; 91: 271-5, 2016 May.
Artículo en Inglés | MEDLINE | ID: mdl-26995269

RESUMEN

It is of great interest to evaluate if there is a relationship between possible sources and trace elements using biomonitoring techniques. In this study, tree bark samples of 171 trees were collected using a biomonitoring technique in the inner city of São Paulo. The trace elements (Al, Ba, Ca, Cl, Cu, Fe, K, Mg, Mn, Na, P, Rb, S, Sr and Zn) were determined by the energy dispersive X-ray fluorescence (EDXRF) spectrometry. The Principal Component Analysis (PCA) was applied to identify the plausible sources associated with tree bark measurements. The greatest source was vehicle-induced non-tailpipe emissions derived mainly from brakes and tires wear-out and road dust resuspension (characterized with Al, Ba, Cu, Fe, Mn and Zn), which was explained by 27.1% of the variance, followed by cement (14.8%), sea salt (11.6%) and biomass burning (10%), and fossil fuel combustion (9.8%). We also verified that the elements related to vehicular emission showed different concentrations at different sites of the same street, which might be helpful for a new street classification according to the emission source. The spatial distribution maps of element concentrations were obtained to evaluate the different levels of pollution in streets and avenues. Results indicated that biomonitoring techniques using tree bark can be applied to evaluate dispersion of air pollution and provide reliable data for the further epidemiological studies.


Asunto(s)
Contaminantes Atmosféricos/análisis , Contaminación del Aire/análisis , Ciudades , Monitoreo del Ambiente/métodos , Corteza de la Planta/química , Oligoelementos/análisis , Árboles , Brasil , Humanos , Análisis de Componente Principal , Espectrometría por Rayos X , Emisiones de Vehículos/análisis
13.
J Mater Sci Mater Med ; 24(4): 863-76, 2013 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-23371768

RESUMEN

The corrosion stability of a W-DLC coated surgical AISI 316L stainless steel in Hanks' solution has been evaluated. Particle induced X-ray emission (PIXE) measurements were performed to evaluate the incorporation of potentially bioactive elements from the physiological solution. The film structure was analyzed by X-ray diffractometry and micro-Raman spectroscopy. The wear behavior was assessed using the sphere-on-disc geometry. The in vitro biocompatibility of the W-DLC film was evaluated by cytotoxicity tests. The corrosion resistance of the stainless steel substrate decreased in the presence of the PVD layer. EIS measurements suggest that this behavior was closely related to the corrosion attack through the coating pores. PIXE measurements revealed the presence of Ca and P in the W-DLC film after immersion in Hanks' solution. This result shows that the PIXE technique can be applied to identify and evaluate the incorporation of bioactive elements by W-DLC films. The film showed good wear resistance and biocompatibility.


Asunto(s)
Materiales Biocompatibles , Análisis Espectral/métodos , Acero Inoxidable , Soluciones , Propiedades de Superficie
14.
J Environ Radioact ; 102(10): 906-10, 2011 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-20421141

RESUMEN

This paper examines the viability of using Canoparmelia texana lichen species as a bioindicator of air pollution by radionuclides and rare earth elements (REEs) in the vicinity of a tin and lead industry. The lichen and soil samples were analyzed for uranium, thorium and REEs by instrumental neutron activation analysis. The radionuclides (226)Ra, (228)Ra and (210)Pb were determined either by Gamma-ray spectrometry (GRS) (soils) or by radiochemical separation followed by gross alpha and beta counting using a gas flow proportional counter (lichens). The lichens samples concentrate radionuclides (on the average 25-fold higher than the background for this species) and REEs (on the average 10-fold higher), therefore they can be used as a fingerprint of contamination by the operation of the tin industry.


Asunto(s)
Contaminantes Radiactivos del Aire/análisis , Elementos Radiactivos/análisis , Monitoreo del Ambiente/métodos , Radioisótopos de Plomo/análisis , Líquenes/química , Metales de Tierras Raras/análisis , Contaminantes Radiactivos del Suelo/análisis , Brasil , Metalurgia , Metales Pesados/análisis , Suelo/análisis
15.
Toxicon ; 56(8): 1443-58, 2010 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-20816886

RESUMEN

Different clinical manifestations have been reported to occur in patients bitten by newborn and adult Bothrops jararaca snakes. Herein, we studied the chemical composition and biological activities of B. jararaca venoms and their immunoneutralization by commercial antivenin at these ontogenetic stages. Important differences in protein profiles were noticed both in SDS-PAGE and two-dimensional electrophoresis. Newborn venom showed lower proteolytic activity on collagen and fibrinogen, diminished hemorrhagic activity in mouse skin and hind paws, and lower edematogenic, ADPase and 5'-nucleotidase activities. However, newborn snake venom showed higher l-amino oxidase, hyaluronidase, platelet aggregating, procoagulant and protein C activating activities. The adult venom is more lethal to mice than the newborn venom. In vitro and in vivo immunoneutralization tests showed that commercial Bothrops sp antivenin is less effective at neutralizing newborn venoms. These findings indicate remarkable differences in biological activities of B. jararaca venom over its development. We suggest that not only venom from adult specimens, but also from specimens at other ontogenetic stages should be included in the venom pool used for raising antibodies. Thus, Bothrops antivenin can efficaciously neutralize proteins lacking in the adult venom pool, especially those that promote more intense hemostatic disturbances in victims of newborn snakes.


Asunto(s)
Bothrops/crecimiento & desarrollo , Venenos de Crotálidos/química , Factores de Edad , Animales , Animales Recién Nacidos , Antivenenos/química , Coagulación Sanguínea/efectos de los fármacos , Bothrops/metabolismo , Creatina Quinasa/sangre , Venenos de Crotálidos/aislamiento & purificación , Venenos de Crotálidos/toxicidad , Hemorragia/inducido químicamente , Dosificación Letal Mediana , Ratones , Agregación Plaquetaria/efectos de los fármacos
16.
Toxicon ; 56(8): 1443-1458, September 8 ,2010.
Artículo en Inglés | Sec. Est. Saúde SP, SESSP-IBPROD, Sec. Est. Saúde SP, SESSP-IBACERVO | ID: biblio-1068264

RESUMEN

Different clinical manifestations have been reported to occur in patients bitten by newborn and adult Bothrops jararaca snakes. Herein, we studied the chemical composition and biological activities of B. jararaca venoms and their immunoneutralization by commercialantivenin at these ontogenetic stages. Important differences in protein profiles were noticed both in SDS-PAGE and two-dimensional electrophoresis. Newborn venom showed lower proteolytic activity on collagen and fibrinogen, diminished hemorrhagic activity in mouse skin and hind paws, and lower edematogenic, ADPase and 50-nucleotidase activities. However, newborn snake venom showed higher L-amino oxidase, hyaluronidase,platelet aggregating, procoagulant and protein C activating activities. The adult venom is more lethal to mice than the newborn venom. In vitro and in vivo immunoneutralization tests showed that commercial Bothrops sp antivenin is less effective at neutralizing newborn venoms. These findings indicate remarkable differences in biological activities ofB. jararaca venom over its development. We suggest that not only venom from adult specimens, but also from specimens at other ontogenetic stages should be included in the venom pool used for raising antibodies. Thus, Bothrops antivenin can efficaciouslyneutralize proteins lacking in the adult venom pool, especially those that promote more intense hemostatic disturbances in victims of newborn snakes.


Asunto(s)
Masculino , Femenino , Humanos , Recién Nacido , Antídotos , Bothrops , Mordeduras de Serpientes , Protrombina , Viperidae , Factor X , Hemostasis
17.
Inhal Toxicol ; 22(1): 84-8, 2010 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-20017596

RESUMEN

Epidemiological studies have demonstrated the adverse effects of particulate matter (PM) inhalation on the respiratory and cardiovascular systems. It has been reported that air pollution may affect the central nervous system and decrease cognitive function. In rats, residual oil fly ash (ROFA) instillation causes decreased motor activity and increased lipid peroxidation in the striatum and the cerebellum. Our objective was to determine whether chronic instillation of particles induces changes in learning and memory in rats and whether oxidants in the hippocampus may contribute to these adverse effects. Forty-five-day-old male Wistar rats were exposed to ROFA by intranasal instillation and were treated with N-acetylcysteine (NAC) at 150 mg/kg i.p. for 30 days. Control groups were exposed to ROFA, NAC, or neither. On days 1, 8, and 30 of the protocol, rats were submitted to the open field test to evaluate habituation. After the last open field session, the rats were killed by decapitation. The hippocampus was used to determine lipid peroxidation (LP) by the thiobarbituric acid-reactive substances test. ROFA instillation induced an increase in LP in the hippocampus compared to all treatment groups (p = .012). NAC treatment blocked these changes. All of the treatment groups presented a decrease in the frequency of peripheral walking (p = .001), rearing (p = .001), and exploration (p = .001) over time. Our study demonstrates that exposure to particles for 30 days and/or NAC treatment do not modify habituation to an open field, a simple form of learning and memory in rats, and that oxidative damage induced by ROFA does not modulate these processes.


Asunto(s)
Contaminantes Atmosféricos/toxicidad , Conducta Animal/efectos de los fármacos , Carbono/toxicidad , Habituación Psicofisiológica/efectos de los fármacos , Hipocampo/efectos de los fármacos , Peroxidación de Lípido/efectos de los fármacos , Material Particulado/toxicidad , Acetilcisteína/farmacología , Administración Intranasal , Animales , Conducta Animal/fisiología , Ceniza del Carbón , Antagonismo de Drogas , Conducta Exploratoria/efectos de los fármacos , Conducta Exploratoria/fisiología , Depuradores de Radicales Libres/farmacología , Habituación Psicofisiológica/fisiología , Hipocampo/metabolismo , Masculino , Malondialdehído/metabolismo , Memoria/efectos de los fármacos , Actividad Motora/efectos de los fármacos , Actividad Motora/fisiología , Estrés Oxidativo/efectos de los fármacos , Desempeño Psicomotor/efectos de los fármacos , Desempeño Psicomotor/fisiología , Ratas , Ratas Wistar
18.
Gen Dent ; 57(4): 363-7, 2009.
Artículo en Inglés | MEDLINE | ID: mdl-19903616

RESUMEN

This study used the radiotracer method to measure the initial enamel wear caused by low- and high-fusing porcelains after glazing or polishing. It also tested the correlation between enamel wear and porcelain surface roughness (Ra). Surface morphology was assessed by optical microscopy. Cylindrical specimens of three porcelains (two high-fusing, one low-fusing) were either autoglazed or polished. Flattened enamel specimens were irradiated with neutrons and submitted to the wear assay for 2,500 cycles in distilled water using a 285 g load; the released beta 32P particles were measured for 10 minutes. For all samples, Ra was recorded with a profilometer before and after testing. Enamel wear was not significantly different for porcelain or finishing method but there was a trend of interaction between the two variables (p = 0.08). A positive correlation was found between enamel wear and the initial Ra of porcelain (r = 0.71). The glazed surfaces of high-fusing porcelains were wavy and had a greater Ra, while the polished surfaces had grooves and pores prior to wear testing. The low-fusing porcelain demonstrated lower Ra and a more homogeneous surface. All abraded surfaces had similar morphology after the wear assay.


Asunto(s)
Esmalte Dental , Porcelana Dental/efectos adversos , Abrasión de los Dientes/etiología , Silicatos de Aluminio , Análisis de Varianza , Pulido Dental/efectos adversos , Porcelana Dental/química , Calor/efectos adversos , Humanos , Tamaño de la Partícula , Estadísticas no Paramétricas , Propiedades de Superficie
19.
Inhal Toxicol ; 20(9): 795-800, 2008 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-18645718

RESUMEN

Several epidemiological studies have linked particulate matter exposure to numerous adverse health effects on the respiratory, cardiovascular, and reproductive systems (Braga et al., 1999; Zanobetti et al., 2000; Anderson et al., 2001; Farhat et al., 2005). More recently, ambient levels of black carbon were associated to impaired cognitive function in children (Suglia et al., 2008), suggesting that the central nervous system (CNS) may be a target of air pollutants. The present study was conducted to (a) determine whether chronic residual oil fly ash (ROFA) exposure promotes behavioral changes and lipid peroxidation in rat brain areas, and (b) determine whether N-acetylcysteine (NAC), a general antioxidant, prevents these effects. Forty-five-day-old male Wistar rats were exposed or not to ROFA by intranasal instillation and were treated or not with NAC (150 mg/kg) ip for 30 days. One day later, rats were submitted to the open field test to evaluate the motor/exploratory activities and emotionality followed by decapitation. Striatum and cerebellum were dissected to determine lipid peroxidation by the accumulation of thiobarbituric acid-reactive substances (TBARS). ROFA instillation induced an increase in lipid peroxidation level in striatum (p = .033) and cerebellum (p = .030), as compared with the control group. NAC treatment blocked these changes. ROFA promoted a decrease in the frequency of peripheral walking (p = .006) and a decrease in exploration (p = .001), which were not blocked by N-acetylcysteine. The present study provides evidence that toxic particles, administered by the respiratory route, induce oxidative stress in structures of the central nervous system, as well as behavioral alterations. The administration of NAC reduces lipid peroxidation at the striatum and cerebellum levels, but does not influence behavioral disturbances.


Asunto(s)
Contaminantes Atmosféricos/toxicidad , Conducta Animal/efectos de los fármacos , Encéfalo/efectos de los fármacos , Carbono/toxicidad , Peroxidación de Lípido/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos , Material Particulado/toxicidad , Acetilcisteína/farmacología , Administración Intranasal , Animales , Encéfalo/metabolismo , Ceniza del Carbón , Modelos Animales de Enfermedad , Conducta Exploratoria/efectos de los fármacos , Depuradores de Radicales Libres/farmacología , Masculino , Actividad Motora/efectos de los fármacos , Ratas , Ratas Wistar , Sustancias Reactivas al Ácido Tiobarbitúrico/metabolismo
20.
Environ Pollut ; 151(2): 334-40, 2008 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-17669566

RESUMEN

The Canoparmelia texana epiphytic lichenized fungi was used to monitor atmospheric pollution in the São Paulo metropolitan region, SP, Brazil. The cluster analysis applied to the element concentration values confirmed the site groups of different levels of pollution due to industrial and vehicular emissions. In the distribution maps of element concentrations, higher concentrations of Ba and Mn were observed in the vicinity of industries and of a petrochemical complex. The highest concentration of Co found in lichens from the São Miguel Paulista site is due to the emissions from a metallurgical processing plant that produces this element. For Br and Zn, the highest concentrations could be associated both to vehicular and industrial emissions. Exploratory analyses revealed that the accumulation of toxic elements in C. texana may be of use in evaluating the human risk of cardiopulmonary mortality due to prolonged exposure to ambient levels of air pollution.


Asunto(s)
Contaminantes Atmosféricos/análisis , Ciudades , Monitoreo del Ambiente/métodos , Líquenes/química , Metales Pesados/análisis , Bario/análisis , Brasil , Bromo/análisis , Cobalto/análisis , Residuos Industriales , Manganeso/análisis , Análisis de Activación de Neutrones , Emisiones de Vehículos , Zinc/análisis
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...