Eliane Tigre Guimarães

Chronic Exposure to Ambient Levels of Urban Particles Affects Mouse Lung Development

RATIONALE Chronic exposure to air pollution has been associated with adverse effects on childrens lung growth. OBJECTIVES We analyzed the effects of chronic exposure to urban levels of particulate matter (PM) on selected phases of mouse lung development. METHODS The exposure occurred in two open-top chambers (filtered and nonfiltered) placed 20 m from a street with heavy traffic in São Paulo, 24 hours/day for 8 months. There was a significant reduction of the levels of PM(2.5) inside the filtered chamber (filtered = 2.9 +/- 3.0 microg/m(3), nonfiltered = 16.8 +/- 8.3 microg/m(3); P = 0.001). At this exposure site, vehicular sources are the major components of PM(2.5) (PM <or= 2.5 microm). Exposure of the parental generation in the two chambers occurred from the 10th to the 120th days of life. After mating and birth of offspring, a crossover of mothers and pups occurred within the chambers, resulting in four groups of pups: nonexposed, prenatal, postnatal, and pre+postnatal. Offspring were killed at the age of 15 (n = 42) and 90 (n = 35) days; lungs were analyzed by morphometry for surface to volume ratio (as an estimator of alveolization). Pressure-volume curves were performed in the older groups, using a 20-ml plethysmograph. MEASUREMENTS AND MAIN RESULTS Mice exposed to PM(2.5) pre+postnatally presented a smaller surface to volume ratio when compared with nonexposed animals (P = 0.036). The pre+postnatal group presented reduced inspiratory and expiratory volumes at higher levels of transpulmonary pressure (P = 0.001). There were no differences among prenatal and postnatal exposure and nonexposed animals. CONCLUSIONS Our data provide anatomical and functional support to the concept that chronic exposure to urban PM affects lung growth.

Exploring the clastogenic effects of air pollutants in São Paulo (Brazil) using the Tradescantia micronuclei assay

This study was designed to determine the clastogenicity of particulate matter (aerodynamic diameter smaller than 10 microm) in the urban polluted air in the city of São Paulo. The Tradescantia-micronucleus (Trad-MCN) assay was used throughout this study to evaluate the clastogenicity of the extracts of the particulate matter. Tradescantia pallida (Rose) Hunt. cv. purpurea, an indigenous cultivar, was used in the Trad-MCN assay. The efficacy of this plant material for the Trad-MCN assay was validated with dose-response studies using formaldehyde and beta radiation. Dose-response curves were established with these known mutagens. The extracts of the PM10 particles at concentrations between 5 and 50 ppm induced a dose-related increase in MCN frequencies. The results indicate that T. pallida is equally sensitive to mutagens as the standard Tradescantia clone 4430 or 03 and the particulate matter in the urban air are clastogenic to the chromosomes of this plant. Inhalation of these particles by urban dwellers may affect their health by inducing similar genetic damage.

Effects of a heat and moisture exchanger and a heated humidifier on respiratory mucus in patients undergoing mechanical ventilation.

Objective: To evaluate the effects of a heat and moisture exchanger and a heated humidifier on respiratory mucus and transportability by cilia and cough in patients undergoing invasive mechanical ventilation (up to 72 hrs). Design: Prospective, randomized, clinical study. Setting: General intensive care unit and university research laboratory. Patients: A total of 32 consecutive patients with acute respiratory failure, who were intubated and mechanically ventilated in the intensive care unit setting, were enrolled in the study. Interventions: Patients were randomly assigned to receive as a humidifying system a heat and moisture exchanger (HME) or heated humidified water (HHW) at the onset of mechanical ventilation (time 0). Respiratory mucus samples were collected by suction using a sterile technique at time 0, 24, 48, and 72 hrs of mechanical ventilation. Measurements and Main Results: Eleven patients were excluded from this study because of either extubation or death before 72 hrs of mechanical ventilation, leaving 12 patients in the HME group and nine patients in the HHW group. Ventilatory variables including minute volume, mean airway pressure, positive end‐expiratory pressure, FIO2, as well as PaO2/FIO2 ratio, fluid balance (last 6 hrs), furosemide, and inotrope administration (last 4 hrs) were recorded. In vitro mucus transportability by cilia was evaluated on the mucus‐depleted frog palate model, and the results were expressed as the mucus transport rate. Cough clearance (an estimation of the interaction between the flow of air and the mucus lining the bronchial walls) was measured using a simulated cough machine, the results being expressed in millimeters. Mucus wettability was measured by the contact angle between a mucus sample drop and a flat glass surface. Mucus rheologic properties (mechanical impedance [log G*] and the ratio between viscosity and elasticity [tan δ]) were measured using a magnetic microrheometer at 1 and 100 cGy/sec deformation frequency. The two humidification groups were comparable in terms of the Acute Physiology and Chronic Health Evaluation II score, age, gender, ventilatory variables, fluid balance, use of inotropes, and furosemide. Conclusion: Ours results indicate that air humidification with either HME or HHW at 32°C (89.6°F) has similar effects on mucus rheologic properties, contact angle, and transportability by cilia in patients undergoing mechanical ventilation, except for transportability by cough, which diminished after 72 hrs of mechanical ventilation in the HME group (p = .0441).

Estudo anatômico foliar do clone híbrido 4430 de Tradescantia: alterações decorrentes da poluição aérea urbana

The relationship between the urban air pollution and respiratory diseases of human populations have been confirmed through several epidemiological studies. Continuous monitoring of air pollutant concentrations is perfomed by CETESB (The State Agency of Air Quality Control) in the city of Sao Paulo. However, biomonitoring programs using plants are other complementary and important ways to measure and prevent the effects of air pollutants on the biological systems and to a certain extent human health. The clone 4430 of Tradescantia has been used in biossays (Trad-MCN, Trad-SH) to monitor the genotoxic potential of several substances. However, the possibility of using the changes in some features of plants from these clones, which are indicators of air pollution effects, has never been explored. Thus, after establishing the structural pattern of these plants, the present study intended to select, among their anatomical characteristics, the most adequate as bioindicators of air quality. Plants of clone 4430 from EMBRAPA-Jaguariuna (out of the influence of air pollution of Sao Paulo city - control) were cultivated in parts under standardised conditions and exposed for three months to the environment of three polluted sites of Sao Paulo: Instituto de Botânica, Cerqueira Cesar and Congonhas. The structural analysis of the leaves revealed the presence of an unstratified epidermis with glandular and non-glandular trichomes in both surfaces, diacytic stomata, mesophyll with only spongy parenchyma, angular collenchyma near to colateral vascular bundles, and water storing cells near the central bundle. No qualitative changes were observed among the leaves from the four studied sites, but significant reductions in the stomata size, metaxylem diameter, and leaf thickness were detected in plants from the polluted sites. The results showed that some structural aspects of the clone 4430 can be used as bioindicators of the effects of the air pollution.

Biomonitoring genotoxic risks under the urban weather conditions and polluted atmosphere in Santo André, SP, Brazil, through Trad-MCN bioassay.

The present study was made to check if the Trad-MCN bioassay, developed with inflorescences of Tradescantia pallida cv. Purpurea, might discriminate genotoxic risks in areas of the city of Santo André (SE Brazil) contaminated by different air pollutants, and periods of the year when risks are higher, and to determine if the variations in the frequency of micronuclei (MCN) can be explained by environmental factors that characterize the stressful situation in each site. Potted plants were exposed in sites highly contaminated by ozone (Capuava and School) and in sites reached by high vehicular emissions (downtown and Celso Daniel Park). Pedroso Park, far from the polluted areas, was taken as reference. From September 2003 to September 2004, 20 young inflorescences were collected twice a week from each place and the frequencies of MCN were estimated. The environmental conditions observed in the polluted sites were stressful enough to promote an increase of MCN, mainly in sites reached by high vehicular emissions. But MCN rates in Capuava and at Celso Daniel Park could not be predicted only by pollutants which characterized the air contamination in these sites. More severe weather conditions, mainly low temperature, relative humidity and rainfall, caused an increase of MCN. Improvement of the biomonitoring system is recommended to minimize this negative influence of weather factors.

Pollen mother cells of Tradescantia clone 4430 and Tradescantia pallida var. purpurea are equally sensitive to the clastogenic effects of X-rays

The Tradescantia micronucleus test is a sensitive bioassay for mutagenesis that may be employed both under field and laboratory conditions. This test has been standardized mostly on the basis of the results obtained with clone 4430. However, this clone is not well adapted to tropical weather, frequently showing problems with growth and flowering. In addition, it is attacked by parasites and insects, a fact that limits its use in field studies aiming at the biomonitoring of air pollution. In the city of São Paulo, Tradescantia pallida (Rose) Hunt. var. purpurea Boom is widely distributed as an ornamental plant in gardens and along roadsides and streets, mostly because of its natural resistance and its easy propagation. In this report, we present dose-response curves indicating that the sensitivity of T. pallida and clone 4430 to X-radiation (1, 10, 25 and 50 cGy) is similar. The results confirm our previous suggestion that T. pallida represents a good alternative for in situ mutagenesis testing in tropical regions, especially biomonitoring studies in which the exposure conditions may not be fully controllable.

Rheological determinants of mucociliary transport in the nose of the rat

The present work was designed to investigate whether the rheological determinants for nasal mucociliary transport are the same in the intact preparation (in situ), as they are when the mucus is added exogenously to the isolated, mucus-depleted frog palate (in vitro). We evaluated the association between estimators of mucociliary transport in both conditions and rheological parameters using multiple regression techniques. Two kinds of rats were used: (a) specific pathogen free (SPF) rats, representing the normal condition of respiratory epithelium; (b) non-SPF rats (NSPF), which have a chronic inflammatory process in the airways. In situ mucociliary clearance (MCC) was determined by measuring the displacement of charcoal particles placed in the nasal septum. In vitro mucociliary transport (MCT) of rat nasal mucus was measured using the isolated frog palate preparation. Mucus rheologic properties were determined by magnetic microrheometry, in oscillatory deformations performed at 1, 10 and 100 radians/sec. No differences were detected between SPF and NSPF rats in terms of rheological parameters. A decreased MCC was found in NSPF in comparison with the SPF group, but no differences were observed between groups in terms of MCT, as could be predicted by rheological data. When all animals were pooled, in situ transport was significantly associated with the viscosity/elasticity ratio, whereas in vitro transport was dependent on the total mechanical impedance of the mucus sample. In conclusion, in situ mucus transport is influenced by other rheological parameters than those associated with in vitro transportability.

Methods for studying mucociliary transport

UNLABELLED Mucociliary transport dysfunctions can impair the quality of life of patients suffering from chronic rhinossinusitis and lead to severe consequences such as alterations in respiratory physiology or even death as in cases of cystic fibrosis and primary ciliary dyskinesia. Therefore, it is crucial to understand the physiology of the mucociliary apparatus and how its components (cilia, mucus-periciliary layer and its interaction) affect the clearance of respiratory secretions. AIMS This paper aims to review and to discuss different techniques for studying mucociliary transport and their clinical and experimental applicability. CONCLUSIONS The methods listed in this revision provide us with valuable information about different aspects of the mucociliary transport. Some of the methods listed are more suitable for clinical practice and present reproducible results. Others, show only applicability in experimental settings due to technical difficulties or financial limitations. However, it is important to emphasize that up to now there is no method that can evaluate ciliary beating frequency (CBF) in vivo and in situ. Such a method would become a valuable tool in the scientific scenario and in the clinical practice, supporting the diagnosis of ciliary dyskinesias and avoiding the use of invasive procedures to corroborate the clinical suspicion.

Métodos de estudo do transporte mucociliar

Mucociliary transport dysfunctions can impair the quality of life of patients suffering from chronic rhinossinusitis and lead to severe consequences such as alterations in respiratory physiology or even death as in cases of cystic fibrosis and primary ciliary dyskinesia. Therefore, it is crucial to understand the physiology of the mucociliary apparatus and how its components (cilia, mucus-periciliary layer and its interaction) affect the clearance of respiratory secretions. AIMS: This paper aims to review and to discuss different techniques for studying mucociliary transport and their clinical and experimental applicability. CONCLUSIONS: The methods listed in this revision provide us with valuable information about different aspects of the mucociliary transport. Some of the methods listed are more suitable for clinical practice and present reproducible results. Others, show only applicability in experimental settings due to technical difficulties or financial limitations. However, it is important to emphasize that up to now there is no method that can evaluate ciliary beating frequency (CBF) in vivo and in situ. Such a method would become a valuable tool in the scientific scenario and in the clinical practice, supporting the diagnosis of ciliary dyskinesias and avoiding the use of invasive procedures to corroborate the clinical suspicion

Tradescantia pallida cv. purpurea Boom in the Characterization of Air Pollution by Accumulation of Trace Elements

Abstract Tradescantia pallida cv. purpurea, a plant species widely employed for ornamentation in Brazil, has been successfully used for monitoring the genotoxicity of various agents by the micronucleus assay. To amplify knowledge about its suitability as a bioindicator species, its capacity for accumulating trace elements from urban air pollution was evaluated. T. pallida was rooted using standardized soil, and the vases were distributed in two highly polluted sites of the urban area of São Paulo, Brazil (Cerqueira César and Congonhas districts), and in one unpolluted control site situated approximately 50 km from downtown São Paulo (in Caucaia do Alto). Approximately six months after exposure to pollutants, adult leaves of this plant were collected monthly for 12 months. The leaves were washed with deionized water, dried, and ground for analyses. Characterization of element levels was carried out by neutron activation analysis. Powdered samples and standards were irradiated at the IEA-R1 nuclear reactor for short and long periods, and concentrations of As, Ba, Br, Ca, Ce, Cl, Cr, Co, Fe, K, La, Mn, Na, Rb, Sb, Sc, Sr, Th, and Zn were determined. Analysis of variance applied to the results indicated that samples from polluted sites present the highest concentrations of Ba, Ce, Cr, Co, Fe, La, Sb, and Sc (p < 0.05). Discriminant analysis revealed that it was possible to distinguish the two polluted areas with a precision of 97.5%, based on the amount of pollutant elements measured in the plants at each site. The results indicated the potential use of T. pallida as an accumulator plant for air pollution biomonitoring.