RESUMO
El ozono (O3) troposférico es el principal oxidante del esmog fotoquímico. Como es un contaminante aéreo, sus efectos están relacionados con la dosis efectiva = [Concentración] x [tiempo de exposición] x [ventilación minuto]. Objetivo: Determinar si el ejercicio físico -que aumenta la ventilación minuto- puede aumentar el daño pulmonar inducido por la exposición a O3 en ratas en reposo. Material y Métodos: Se usó 4 series de ratas Sprague-Dawley juveniles. Dos series fueron expuestas a 0,5 ppm de O3 (4 h diarias por 2 días) en reposo (n = 13) o durante ejercicio (n = 12). Dos series control respiraron aire filtrado (AF) en reposo (n = 13) o durante sesiones de ejercicio (n = 13), en una rueda vertical giratoria (15 min de ejercicio alternados con 15 min de descanso hasta completar 4 h diarias durante 2 días). Las ratas fueron eutanasiadas y se determinó la razón peso húmedo/peso seco (PH/PS) en el pulmón izquierdo. En el lavado broncoalveolar (LBA) del pulmón derecho, se determinó recuento total de células, proteínas totales y actividad de gamma-glutamiltraspeptidasa (GGT). Resultados: la razón PH/PS y el recuento de células y las proteínas del LBA aumentaron en las ratas en reposo expuestas a O3 comparadas con las ratas en reposo que respiraron AF (p < 0,05 ANOVA & Newman-Keuls). La actividad de GGT en el LBA fue mayor en las ratas que en ejercicio respiraron AF en comparación con las ratas que respiraron AF en reposo (p < 0,05). Hubo aumento de GGT, proteínas y recuento de células en el LBA de la serie [ejercicio + O3] comparada con la serie [reposo + O3] (p < 0,05). Conclusión: El ejercicio físico aumenta el daño pulmonar inducido por la exposición aguda e intermitente a 0,5 ppm de O3 en ratas juveniles.
Tropospheric ozone (O3) is the major oxidant of photochemical smog. Being an air pollutant, its effects are related to effective dose = [Concentration] x [exposure time] x [pulmonary ventilation]. Objective: Determine whether physical exercise -that increases pulmonary ventilation- is able to augment the pulmonary damage induced by O3 exposure in resting rats. Material and Methods: Four series of juvenile Sprague-Dawley rats were used. Two series were exposed to 0.5 ppm O3 (4 hours a day for 2 days) at rest (n=13) or during exercise (n=12). Two control series breathed filtered air (FA) at rest (n=13) or during exercise sessions (n=13), in a vertical rotary wheel (15 min exercise alternated with 15 min resting until to completing 4 hours a day for 2 days). Rats were euthanized and wet weight / dry weight ratio (W/D ratio) was determined in left lung. Total cell counting, total protein content and γ-glutamyltraspeptidase (GGT) activity were determined in the right lung bronchoalveolar lavage fluid (BALF). Results: W/D weight ratio as well as total cell counting and protein content increased in BALF from resting rats exposed to O3 as compared with resting rats breathing FA (p < 0.05 ANOVA & Newman-Keuls test). GGT activity in BALF increased in rats under exercise breathing FA as compared with resting rats breathing FA (p<0.05). GGT, proteins and cells counting increased in BALFfrom series [exercise + O3] as compared to series [resting + O3] (p< 0.05). Conclusion: Physical exercise increases lung damage induced by intermittent and acute 0.5 ppm O3 exposure in juvenile rats.
Assuntos
Animais , Ratos , Exercício Físico , Pneumopatias/induzido quimicamente , Oxidantes Fotoquímicos/efeitos adversos , Ozônio/efeitos adversos , Análise de Variância , Pneumopatias/fisiopatologia , Fatores de Tempo , Lavagem Broncoalveolar , Ratos Sprague-Dawley , gama-GlutamiltransferaseRESUMO
OBJECTIVE: To evaluate the cytological damage and glutathione peroxidase (GPX) content in the nasal epithelium of residents of Southwest Metropolitan Mexico City (SWMMC) along 1 year of ozone and PM(10) exposure. METHOD: Four nasal scrapings were obtained in 20 volunteers from a control low polluted city and SWMMC permanent residents (n = 20) during 1 year. The scrapings were obtained in September and December 2004, and February and May 2005. One part of the scraping was stained by hematoxylin-eosin technique for cytological evaluation and a second part was stained by immunocytochemistry method to evaluate GPX concentration by morphometry. RESULTS: Control subjects: in total, 30% had no cytological alterations and 70% showed only mild or moderate inflammation in four nasal scrapings. All SWMMC residents showed moderate to severe inflammatory processes in some scrapings. Additionally, dysplasia was found once (in 2 cases) or more than on scraping in five cases (25%). GPX concentration in the control group remained highest in median values throughout the study. SWMMC residents with the highest median values of GPX content were found in the May and September scrapings, and the lowest median values were found in December and February when Ozone and PM(10) levels are increased (P < or = 0.05). A lower GPX content was found as the cytological damage increased (P < or = 0.001). CONCLUSION: Cytological evaluation of nasal epithelium and GPX immunodetection are satisfactory methods to evaluate the earliest damage produced by atmospheric pollution in heavily contaminated cities.
Assuntos
Poluentes Atmosféricos/efeitos adversos , Glutationa Peroxidase/metabolismo , Mucosa Nasal/efeitos dos fármacos , Oxidantes Fotoquímicos/efeitos adversos , Ozônio/efeitos adversos , Material Particulado/efeitos adversos , Adulto , Cidades , Feminino , Humanos , Inflamação/induzido quimicamente , Inflamação/epidemiologia , Inflamação/patologia , Masculino , México/epidemiologia , Mucosa Nasal/enzimologia , Mucosa Nasal/patologia , Estações do Ano , Saúde da População Urbana , População Urbana , Adulto JovemRESUMO
Oxidative stress is implicated in the premature death of dopamine neurons in substantia nigra in Parkinson's disease. The incidence of Parkinson's disease is higher in men than in women, and estrogen may provide neuroprotection against oxidative damage. We examined the protective effects of estrogen on rat nigral death after chronic ozone inhalation. Ozone inhalation produced impaired nigral cell morphology and loss of dopamine neurons in ovariectomized rats. This was counteracted after 60 days of 17beta-estradiol treatment, when blood levels were highest. These results indicate that ozone exposure may be a useful Parkinson's disease model and neuroprotection afforded by 17beta-estradiol is dependent on the high levels achieved after its prolonged administration.
Assuntos
Estradiol/farmacologia , Neurônios/efeitos dos fármacos , Oxidantes Fotoquímicos/efeitos adversos , Estresse Oxidativo/efeitos dos fármacos , Ozônio/efeitos adversos , Substância Negra/citologia , Animais , Western Blotting/métodos , Contagem de Células/métodos , Morte Celular/efeitos dos fármacos , Interações Medicamentosas , Estradiol/sangue , Feminino , Imuno-Histoquímica/métodos , Peroxidação de Lipídeos/efeitos dos fármacos , Ratos , Ratos Wistar , Fatores de Tempo , Tirosina 3-Mono-Oxigenase/metabolismoRESUMO
BACKGROUND: High levels of albumin in some biological fluids are generally associated with abnormal process of permeation during an inflammatory response. In some cases, the nasal albumin levels can be used as an indirect molecular marker of epithelial damage. METHODS: We carried out an evaluation study of nasal albumin from a population (14 volunteers), exposed for 15 days to high urban pollution (O(3) 10.644 ppm/h average 10.2 h/day) in Mexico City for the first time, and when they returned to their original non-polluted city (Veracruz, State of Veracruz, Mexico) 13 days later. The nasal albumin samples were fractionated by gel electrophoresis techniques, and albumin determination analyses were done by gel scanning. The densitometry values obtained from the albumin-stained bands were compared with an internal standard and the average values compared with other groups used as reference, under conditions of non-polluted and polluted cities. RESULTS: Our findings showed in the group exposed to pollution for the first time a significant increment 2 days after entering Mexico City urban pollution. They, subsequently, had a progressive recovery 4 days later up to day 13 in their original place of residence. The reference groups for comparison were from a non-polluted city (at sea level on the Pacific Ocean) Manzanillo, Colima, Mexico, and a very polluted urban metropolis (Mexico City). The group showed a significant difference of protein levels about 2.5 higher apparently at the expense of albumin. These populations were permanent residents of environmental conditions we wanted to evaluate. Our approach was to monitor quantitatively the time course of the change of a biochemical parameter in normal mucus from a population never exposed to Mexico City urban pollution. CONCLUSIONS: Our conclusions from this study point out that pollution causes diverse mucosal damage that can be followed by biochemical monitoring.
Assuntos
Poluição do Ar/efeitos adversos , Albuminas/metabolismo , Exposição por Inalação/efeitos adversos , Mucosa Nasal/metabolismo , Oxidantes Fotoquímicos/efeitos adversos , Ozônio/efeitos adversos , Adulto , Biomarcadores , Humanos , População UrbanaRESUMO
Daily counts of non-accidental deaths in Santiago, Chile, from 1988 to 1996 were regressed on six air pollutants--fine particles (PM2.5), coarse particles (PM10-2.5), CO, SO2, NO2, and O3. Controlling for seasonal and meteorological conditions was done using three different models--a generalized linear model, a generalized additive model, and a generalized additive model on previously filtered data. Single- and two-pollutant models were tested for lags of 1-5 days and the average of the previous 2-5 days. The increase in mortality associated with the mean levels of air pollution varied from 4 to 11%, depending on the pollutants and the way season of the year was considered. The results were not sensitive to the modeling approaches, but different effects for warmer and colder months were found. Fine particles were more important than coarse particles in the whole year and in winter, but not in summer. NO2 and CO were also significantly associated with daily mortality, as was O3 in the warmer months. No consistent effect was observed for SO2. Given particle composition in Santiago, these results suggest that combustion-generated pollutants, especially from motor vehicles, may be associated with increased mortality. Temperature was closely associated with mortality. High temperatures led to deaths on the same day, while low temperatures lead to deaths from 1 to 4 days later.
Assuntos
Poluição do Ar/efeitos adversos , Causas de Morte , Mortalidade/tendências , Adolescente , Adulto , Idoso , Monóxido de Carbono/efeitos adversos , Criança , Pré-Escolar , Chile/epidemiologia , Atestado de Óbito , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Veículos Automotores , Dióxido de Nitrogênio/efeitos adversos , Oxidantes Fotoquímicos/efeitos adversos , Ozônio/efeitos adversos , Tamanho da Partícula , Estações do Ano , Dióxido de Enxofre/efeitos adversos , Temperatura , População UrbanaRESUMO
In a panel study of Mexican children (5-13 y of age) with mild asthma, the authors studied the relationship between ozone exposure and the course of childhood asthma. Decrements in peak expiratory flow rate were associated with ozone, and respiratory symptoms were associated with both ozone level and ambient particulate matter (< 10 microm) level. After the authors adjusted for minimum temperature and autocorrelation in the data, they determined that an increase of 50 ppb in a daily ozone 1-h maximum was related to an 8% increase in cough (95% confidence interval = 2, 15); a 24% increase in phlegm (95% confidence interval = 13, 35); and an 11% increase in low respiratory symptoms index (95% confidence interval = 5, 19). The authors concluded that children with mild asthma who resided in the south of Mexico City were affected adversely by the high ozone ambient levels observed in this area.
Assuntos
Asma/fisiopatologia , Exposição Ambiental/efeitos adversos , Oxidantes Fotoquímicos/efeitos adversos , Ozônio/efeitos adversos , Doença Aguda , Adolescente , Asma/complicações , Criança , Pré-Escolar , Tosse/etiologia , Exposição Ambiental/análise , Feminino , Humanos , Estudos Longitudinais , Masculino , México , Oxidantes Fotoquímicos/análise , Ozônio/análise , Pico do Fluxo Expiratório , Prevalência , Escarro , Saúde da População UrbanaRESUMO
To evaluate methods of reducing exposure of school children in southwest Mexico City to ambient ozone, outdoor ozone levels were compared to indoor levels under three distinct classroom conditions: windows/doors open, air cleaner off; windows/doors closed, air cleaner off; windows/doors closed, air cleaner on. Repeated two-minute average measurements of ozone were made within five minutes of each other inside and outside of six different school classrooms while children were in the room. Outdoor ozone two-minute average levels varied between 64 and 361 ppb; mean outdoor levels were above 160 ppb for each of the three conditions. Adjusting for outdoor relative humidity, for a mean outdoor ozone concentration of 170 ppb, the mean predicted indoor ozone concentrations were 125.3 (+/- 5.7) ppb with windows/doors open; 35.4 (+/- 4.6) ppb with windows/doors closed, air cleaner on. The mean predicted ratios of indoor to outdoor ozone concentrations were 0.71 (+/- 0.03) with windows/doors open; 0.18 (+/- 0.02) ppb with windows/doors closed, air cleaner off; and 0.15 (+/- 0.02) ppb with windows/doors closed, air cleaner on. As outdoor ozone concentrations increased, indoor ozone concentrations increased more rapidly with windows and doors open than with windows and doors closed. Ozone exposure in Mexican schools may be significantly reduced, and can usually be kept below the World Health Organization (WHO) guideline of 80 ppb, by closing windows and doors even when ambient ozone levels reach 300 ppb or more.
Assuntos
Poluição do Ar/análise , Exposição Ambiental , Oxidantes Fotoquímicos/análise , Ozônio/análise , Poluição do Ar em Ambientes Fechados/análise , Criança , Humanos , México , Oxidantes Fotoquímicos/efeitos adversos , Ozônio/efeitos adversosRESUMO
Glutathione S-transferases (GSTs) are principally involved in detoxication. These enzymes can be induced by an increased flux of substrate, such as occurs during pro-oxidative stress or antioxidant deficiency. We tested the hypothesis that the postulated oxidative stress in severe malnutrition would result in induction of GSTs in erythocytes. Erythrocyte GST activity towards 1-chloro-2, 4-dinitrobenzene (CDNB) was measured in 271 malnourished children (22 undernourished; 92 marasmic; 82 kwashiorkor; 75 marasmic-kwashiorkor) and 48 healthy children. GST activity in the malnourished children was significnatly higher than the control group (p < 0.01). The GST activity in the four classes of malnutrition did not differ. There was a weak relationship between GST activity and the height deficit, but not with the weight deficit, or the clinical features displayed by the children. The 11 children that died had a higher value than the survivors. There was no change in GST with anthropometric recovery. We conclude that erythrocyte GST has been induced in children with malnutrition. Induction of erythrocyte GST may be the result of exposure of the children to oxidative stress during the months prior to their presentation with severe malnutrition (AU)