Effects of Air Pollution on Lung Innate Lymphoid Cells: Review of In Vitro and In Vivo Experimental Studies.

Outdoor air pollution is associated with respiratory infections and allergies, yet the role of innate lymphoid cells (ILCs) in pathogen containment and airway hyperresponsiveness relevant to effects of air pollutants on ILCs is poorly understood. We conducted a systematic review to evaluate the available evidence on the effect of outdoor air pollutants on the lung type 1 (ILC1) and type 2 ILCs (ILC2) subsets. We searched five electronic databases (up to Dec 2018) for studies on the effect of carbon monoxide (CO), sulfur dioxide (SO2), nitrogen dioxide (NO2), diesel exhaust particles (DEP), ozone (O3), and particulate matter (PM) on respiratory ILCs. Of 2209 identified citations, 22 full-text papers were assessed for eligibility, and 12 articles describing experimental studies performed in murine strains (9) and on human blood cells (3) were finally selected. Overall, these studies showed that exposure to PM, DEP, and high doses of O3 resulted in a reduction of interferon gamma (IFN-γ) production and cytotoxicity of ILC1. These pollutants and carbon nanotubes stimulate lung ILC2s, produce high levels of interleukin (IL)-5 and IL-13, and induce airway hyperresponsiveness. These findings highlight potential mechanisms by which human ILCs react to air pollution that increase the susceptibility to infections and allergies.

Analysis of the effects of mesoporous silica particles SBA-15 and SBA-16 in Streptococcus pneumoniae transformation process.

Streptococcus pneumoniae are natural competent bacteria which requires the presence of a pheromone-like molecule to do the transformation process. This study verified the influence of mesoporous silica (SBA-15 and SBA-16) on the transformation process in S. pneumoniae using a donor DNA obtained from a mutant strain of this microorganism (Sp360∆luxS). The results showed that mesoporous silica SBA-15 and SBA-16 particles doubled the transformation ratio frequency compared with negative control (without nanoparticles) in using SBA-15 (ratio 1.81 ± 0.04) and SBA-16 (ratio 2.18 ± 0.22). We demonstrated the how mesoporous silica nanoparticles were able to increase the pneumococcus transformations, which could possibly lead to the acquisition of virulence factor genes and resistance of antibiotics.

Drosophila melanogaster as model organism for monitoring and analyzing genotoxicity associated with city air pollution.

This study evaluated the genotoxic potential of atmospheric pollution associated with urbanization using the model organism Drosophila melanogaster and the Comet assay with hemolymph cells. Larvae were exposed to atmospheric compounds in an urban and a rural area in the municipality of Vitória de Santo Antão, Pernambuco, Brazil, for 6 days (from the embryo stage to the third larval stage) in April 2015 and April 2017. The results were compared to a negative environmental control group exposed to a preserved area (Catimbau National Park) and to a negative control exposed to the laboratory room conditions. The Comet assay demonstrated significant genetic damage in the organisms exposed to the urban area compared with those exposed to the rural area and negative control groups. The evidences were supported by particulate matter analysis showing higher photopeaks of chemical elements such as aluminum, silicon, sulfur, potassium, calcium, titanium, and iron, associated to road dust fraction in urban environment. Once again, the results confirm D. melanogaster an ideal bioindicator organism to monitor genotoxic hazard associated with atmospheric pollution.

Carbonaceous particulate matter on the lung surface from adults living in São Paulo, Brazil.

OBJECTIVES: We therefore sought to identify the exposures associated with lung surface in long-term residents of São Paulo, Brazil. METHODS: Lung surface carbon were analyzed in 72 autopsy specimens by image analysis. Smoking history, measured PM10 nearest to the home, distance to main road, and distance-weighted traffic density were used as exposure variables. Data are summarized as median (IQR), and compared by Mann Whitney Test, with correlations done by Spearman's correlation. RESULTS: There was no association between lung surface and age or gender. There was no statistically significant association in lung surface between smokers and non-smokers 6.74 cm2 (3.47 to 10.02) versus 5.20cm2 (2.29 to 7.54), and there was no significant association between lung surface carbon and exposure to environmental PM and markers of traffic exposure. CONCLUSION: We did not find a statistically significant association between lung surface and smokers and non-smokers, and no statistically significant association between lung surface carbon and environmental exposure variables. These results suggest that lung surface carbon in long-term residents of São Paulo may predominately be from environmental PM, but the most appropriate environmental exposure marker remains unclear.

Organic compounds present in airborne particles stimulate superoxide production and DNA fragmentation: role of NOX and xanthine oxidase in animal tissues.

Suspended particulate matter trigger the production of reactive oxygen species. However, most of the studies dealing with oxidative damage of airborne particles focus on the effects of individual compounds and not real mixtures. In order to study the enzymatic superoxide production resulting from the exposition to a complex mixture, we derived organic extracts from airborne particles collected daily in an urban area and exposed kidney, liver, and heart mammal tissues. After that, we measured DNA damage employing the comet assay. We observed that in every tissue, NADPH oxidase and xanthine oxidase were involved in O2 (-) production when they were exposed to the organic extracts, as the lucigenin's chemiluminescence decays when enzymes were inhibited. The same trend was observed with the percentage of cells with comets, since DNA damage was higher when they were exposed to same experimental conditions. Our data allow us to hypothesize that these enzymes play an important role in the oxidative stress produced by PAHs and that there is a mechanism involving them in the O2 (-)generation.

[The effect of air pollutants on birth weight in medium-sized towns in the state of São Paulo]. / O papel dos poluentes atmosféricos sobre o peso ao nascer em cidade de médio porte Paulista.

OBJECTIVE: To investigate the effect of air pollution on birth weight in a medium-sized town in the State of São Paulo, Southeast Brazil. METHODS: Cross-sectional study using data of live births to mothers residing in São José dos Campos from 2005 to 2009. Data was obtained from the Department of Information and Computing of the Brazilian Unified Health System. Air pollutant data (PM, SO and O) and daily averages of their concentrations were obtained from the Environmental Sanitation & Technology Company. Statistical analysis was performed by linear and logistic regressions using the Excel and STATA v.7 software programs. RESULTS: Maternal exposure to air pollutants was not associated with low birth weight, with the exception of exposure to SO within the last month of pregnancy (OR=1,25; IC95% 1,00-1,56). Maternal exposure to PM and SO during the last month of pregnancy led to lower weight at birth (0.28 g and 3.15 g, respectively) for each 1mg/m(3) increase in the concentration of these pollutants, but without statistical significance. CONCLUSIONS: This study failed to identify a statistically significant association between the levels of air pollutants and birth weight, with the exception of exposure to SO within the last month of pregnancy.

Altered gene expression in HepG2 cells exposed to a methanolic coal dust extract.

Exposure to coal dust has been associated with different chronic diseases and mortality risk. This airborne pollutant is produced during coal mining and transport activities, generating environmental and human toxicity. The aim of this study was to determine the effects of a coal dust methanolic extract on HepG2, a human liver hepatocellular carcinoma cell line. Cells were exposed to 5-100ppm methanolic coal extract for 12h, using DMSO as control. MTT and comet assays were used for the evaluation of cytotoxicity and genotoxicity, respectively. Real time PCR was utilized to quantify relative expression of genes related to oxidative stress, xenobiotic metabolism and DNA damage. Coal extract concentrations did not induce significant changes in HepG2 cell viability after 12h exposure; however, 50 and 100ppm of the coal extract produced a significant increase in genetic damage index with respect to negative control. Compared to vehicle control, mRNA CYP1A1 (up to 163-fold), NQO1 (up to 4.7-fold), and GADD45B (up to 4.7-fold) were up regulated, whereas PRDX1, SOD, CAT, GPX1, XPA, ERCC1 and APEX1 remained unaltered. This expression profile suggests that cells exposed to coal dust extract shows aryl hydrocarbon receptor-mediated alterations, changes in cellular oxidative status, and genotoxic effects. These findings share some similarities with those observed in liver of mice captured near coal mining areas, and add evidence that living around these industrial operations may be negatively impacting the biota and human health.

Impaired cardiac mitochondrial function and contractile reserve following an acute exposure to environmental particulate matter.

BACKGROUND: It has been suggested that mitochondrial function plays a central role in cardiovascular diseases associated with particulate matter inhalation. The aim of this study was to evaluate this hypothesis, with focus on cardiac O2 and energetic metabolism, and its impact over cardiac contractility. METHODS: Swiss mice were intranasally instilled with either residual oil fly ash (ROFA) (1.0 mg/kg body weight) or saline solution. After 1, 3 or 5 h of exposure, O2 consumption was evaluated in heart tissue samples. Mitochondrial respiration, respiratory chain complexes activity, membrane potential and ATP content and production rate were assessed in isolated mitochondria. Cardiac contractile reserve was evaluated according to the Langendorff technique. RESULTS: Three hours after ROFA exposure, tissue O2 consumption was significantly decreased by 35% (from 1180 +/- 70 to 760 +/- 60 ng-at O/min g tissue), as well as mitochondrial rest (state 4) and active (state 3) respiration, by 30 and 24%, respectively (control state 4: 88 +/- 5 ng-at O/min mg protein; state 3: 240 +/- 20 ng-at O/min mg protein). These findings were associated with decreased complex II activity, mitochondrial depolarization and deficient ATP production. Even though basal contractility was not modified (control: 75 +/- 5 mm Hg), isolated perfused hearts failed to properly respond to isoproterenol in ROFA-exposed mice. Tissue O2 consumption rates positively correlated with cardiac contractile state in controls (r2 = 0.8271), but not in treated mice (r2 = 0.1396). GENERAL SIGNIFICANCE: The present results show an impaired mitochondrial function associated with deficient cardiac contractility, which could represent an early cardiovascular alteration after the exposure to environmental particulate matter.

In utero exposure to air pollution lowers erythrocyte antioxidant defense and decreases weight in adult mice.

In this study, we tested the influence of ambient air pollution on different phases of development of adult mice. With respect to adult weight, the animals that had spent their in utero period exposed to pollution showed less weight gain over their lifetime, as well as lower activity levels of the antioxidant enzymes catalase, superoxide dismutase (SOD) and glutathione peroxidase (GPx). Our study suggests that contact with atmospheric pollutants during the foetal period produces important changes on enzymatic erythrocyte antioxidant defense and weight in adult mice.

Air pollution in autoimmune rheumatic diseases: a review.

Air pollution consists of a heterogeneous mixture of gasses and particles that include carbon monoxide, nitrates, sulfur dioxide, ozone, lead, toxic by-product of tobacco smoke and particulate matter. Oxidative stress and inflammation induced by inhaled pollutants may result in acute and chronic disorders in the respiratory system, as well as contribute to a state of systemic inflammation and autoimmunity. This paper reviews the mechanisms of air contaminants influencing the immune response and autoimmunity, and it focuses on studies of inhaled pollutants triggering and/or exacerbating rheumatic diseases in cities around the world. Remarkably, environmental factors contribute to the onset of autoimmune diseases, especially smoking and occupational exposure to silica in rheumatoid arthritis and systemic lupus erythematosus. Other diseases such as scleroderma may be triggered by the inhalation of chemical solvents, herbicides and silica. Likewise, primary vasculitis associated with anti-neutrophil cytoplasmic antibody (ANCA) may be triggered by silica exposure. Only few studies showed that air pollutants could trigger or exacerbate juvenile idiopathic arthritis and systemic lupus erythematosus. In contrast, no studies of tropospheric pollution triggering inflammatory myopathies and spondyloarthropathies were carried out. In conclusion, air pollution is one of the environmental factors involved in systemic inflammation and autoimmunity. Further studies are needed in order to evaluate air pollutants and their potentially serious effects on autoimmune rheumatic diseases and the mechanisms involved in the onset and the exacerbation of these diseases.

How the redox state of tobacco 'Bel-W3' is modified in response to ozone and other environmental factors in a sub-tropical area?

This study intended to determine whether the redox state in plants of Nicotiana tabacum 'Bel-W3' fluctuates in response to the environmental factors in a sub-tropical area contaminated by ozone (São Paulo, SE-Brazil) and which environmental factors are related to this fluctuation, discussing their biomonitoring efficiency. We comparatively evaluated the indicators of redox state (ascorbic acid, glutathione, superoxide dismutase, ascorbate peroxidase, and glutathione reductase) and leaf injury in 17 field experiments performed in 2008. The redox state was explained by the combined effects of chronic levels of O(3) and meteorological variables 4-6 days prior to the plant sampling. Moderate leaf injury was observed in most cases. The redox state of tobacco decreases few days after their placement in the sub-tropical environment, causing them to become susceptible to oxidative stress imposed by chronic doses of O(3). Its bioindicator efficiency would not be diminished in such levels of atmospheric contamination.

Hydrogen sulfide prevents ethanol-induced gastric damage in mice: role of ATP-sensitive potassium channels and capsaicin-sensitive primary afferent neurons.

The aim of this study was to evaluate the protective effect of hydrogen sulfide (H(2)S) on ethanol-induced gastric lesions in mice and the influence of ATP-sensitive potassium (K(ATP)) channels, capsaicin-sensitive sensory afferent neurons, and transient receptor potential vanilloid (TRPV) 1 receptors on such an effect. Saline and L-cysteine alone or with propargylglycine, sodium hydrogen sulfide (NaHS), or Lawesson's reagent were administrated for testing purposes. For other experiments, mice were pretreated with glibenclamide, neurotoxic doses of capsaicin, or capsazepine. Afterward, mice received L-cysteine, NaHS, or Lawesson's reagent. After 30 min, 50% ethanol was administrated by gavage. After 1 h, mice were sacrificed, and gastric damage was evaluated by macroscopic and microscopic analyses. L-cysteine, NaHS, and Lawesson's reagent treatment prevented ethanol-induced macroscopic and microscopic gastric damage in a dose-dependent manner. Administration of propargylglycine, an inhibitor of endogenous H(2)S synthesis, reversed gastric protection induced by L-cysteine. Glibenclamide reversed L-cysteine, NaHS, or Lawesson's reagent gastroprotective effects against ethanol-induced macroscopic damage in a dose-dependent manner. Chemical ablation of sensory afferent neurons by capsaicin reversed gastroprotective effects of L-cysteine or H(2)S donors (NaHS or Lawesson's reagent) in ethanol-induced macroscopic gastric damage. Likewise, in the presence of the TRPV1 antagonist capsazepine, the gastroprotective effects of L-cysteine, NaHS, or Lawesson's reagent were also abolished. Our results suggest that H(2)S prevents ethanol-induced gastric damage. Although there are many mechanisms through which this effect can occur, our data support the hypothesis that the activation of K(ATP) channels and afferent neurons/TRPV1 receptors is of primary importance.

Increased levels of outdoor air pollutants are associated with reduced bronchodilation in children with asthma.

BACKGROUND: Increased outdoor air pollution levels are associated with more frequent use of rescue inhalers in subjects with asthma. However, it is unknown whether this phenomenon is explained by an air pollution-mediated increase in respiratory symptom severity or whether air pollutants decrease the efficacy of short-acting beta-agonists (SABAs). METHODS: We examined the relationship between the percentage change in FEV(1) after SABA use with outdoor air pollution exposure in 85 children with asthma who were 7 to 12 years of age. Outdoor air pollution exposure was determined by measuring nitrogen dioxide (NO(2)), ozone (O(3)), and fine particulate matter (ie, particulate matter with an aerodynamic diameter < 2.5 microm [PM(2.5)]) levels. These measurements were obtained from the Mexico City Automated Monitoring Network from network sites located within a 5-km radius of each child's home and school. RESULTS: We found that a same-day interquartile increase of 10 parts per billion (ppb) in NO(2) concentration was associated with a reduced response of FEV(1) to SABA therapy (-15%; 95% CI, -29 to -0.5). This association was also significant when considering NO(2) levels in each of the preceding 3 days. An interquartile O(3) increase (16 ppb) in the preceding fifth day was associated with a reduced response to SABA (-11%; 95% CI, -23 to -1); an interquartile PM(2.5) increase (14 microg/m(3)) was not associated with any significant reductions in the response to SABA therapy. These associations were not observed in children receiving therapy with inhaled corticosteroids. CONCLUSIONS: Our results suggest that recent exposure to NO(2) and possibly O(3) may reduce the response to SABAs in producing bronchodilation in children with asthma. The association between NO(2) and FEV(1) response to SABA administration may have important implications in understanding how outdoor air pollution levels relate to asthma control.

Influence of roadside pollution on the phylloplane microbial community of Alnus nepalensis (Betulaceae)

The North Eastern region of India is undergoing industrial development at a faster rate than expected. Roads form the main system of transportation and communication owing to the hilly topography of the region. Automobiles discharge a number of gaseous and trace metal contaminants. Human activities like stone grinding, road construction and sand milling also increase the atmospheric dust and heavy metal contaminant level. These contaminants get settled on leaf surfaces at roadsides and enter in contact with phylloplane microorganisms. This study compares microorganisms on leaf surfaces of alder (Alnus nepalensis (Betulaceae)) on roadside and non-roadside environments. Two sites dominated by alder were selected. One at a busy road intersection on the National Highway no. 44 in Shillong with high traffic density (8 000-9 000 heavy vehicles/day), taken as the polluted site and the other one in a forest approximately 500 m away from the roadside considered as the unpolluted site. Analysis of phylloplane microorganisms, lead, zinc, copper, cadmium and sulphur was carried out from leaves. The bacterial population was higher at the unpolluted site. Bacterial population showed a significant negative correlation with lead, zinc, copper, cadmium and sulphur. Similarly, fungal population was higher at the unpolluted site. A total of 29 fungal species were isolated from the phylloplane of A. nepalensis (polluted site 16 species; unpolluted site 28 species). Some fungal forms like Mortierella sp., Fusarium oxysporum and Aureobasidium pollulans were dominant in the polluted site. Numbers of phylloplane fungi and bacteria were significantly reduced in the polluted site. The correlation coefficient indicated a detrimental effect of metals like lead, zinc, copper, cadmium and sulphur on the microbial community of leaf surfaces. The specificity of certain fungi to the unpolluted site may be attributed to their sensitivity to pollution. The predominance of Aureobasidium pollulans, Fusarium oxysporum and Mortierella sp. in the polluted site may be due to their resistance to pollutants in roadside conditions. Rev. Biol. Trop. 56 (3): 1521-1529. Epub 2008 September 30.

La región nororiental de la India está experimentando un rápido desarrollo industrial y debido a la topografía montañosa de la región, los automóviles descargan variedad de contaminantes. Actividades humanas como moler piedra y construir caminos también aumentan el polvo atmosférico y la contaminación con metales pesados. Este estudio compara microorganismos en superficies foliares del árbol Alnus nepalensis (Betulaceae). Se estudió uno sitio en una intersección de Shillong, con alta densidad de tráfico (8 000-9 000 vehículos pesados/día), tomada como el sitio contaminado, y otro en un bosque aproximadamente a 500 m de la carretera (sitio no contaminado). Se contabilizaron bacterias, hongos, plomo, zinc, cobre, cadmio y sulfuro. La población bacteriana era más alta en el sitio no contaminado. La población bacteriana mostró una correlación negativa significativa con el contenido de plomo, cinc, cobre, cadmio y sulfuro foliares en el sitio contaminado, mientras que en el sitio no contaminado la correlación fue insignificante. La población de hongos también fue más alta en el sitio no contaminado. Un total de 29 especies de hongos fueron aislados A. nepalensis: 16 en el sitio contaminado y 28 en el no contaminado. Algunas especies de hongos como Mortierella sp., Fusarium oxysporum y Aureobasidium pollulans fueron dominantes en el sitio contaminado. El número de hongos y bacterias fue significativamente menor en el sitio contaminado. El coeficiente de correlación indicó un efecto perjudicial de metales como el plomo, el zinc, el cobre, el cadmio y el sulfuro en esta comunidad que habitan superficies de hojas. La especificidad de ciertos hongos al sitio no contaminado se puede atribuir a su sensibilidad a la contaminación. El predominio de Aureobasidium pollulans, Fusarium oxysporum y Mortierella sp. en el sitio contaminado puede ser debido a su resistencia a los agentes contaminadores.

Influence of roadside pollution on the phylloplane microbial community of Alnus nepalensis (Betulaceae).

The North Eastern region of India is undergoing industrial development at a faster rate than expected. Roads form the main system of transportation and communication owing to the hilly topography of the region. Automobiles discharge a number of gaseous and trace metal contaminants. Human activities like stone grinding, road construction and sand milling also increase the atmospheric dust and heavy metal contaminant level. These contaminants get settled on leaf surfaces at roadsides and enter in contact with phylloplane microorganisms. This study compares microorganisms on leaf surfaces of alder (Alnus nepalensis (Betulaceae)) on roadside and non-roadside environments. Two sites dominated by alder were selected. One at a busy road intersection on the National Highway no. 44 in Shillong with high traffic density (8 000-9 000 heavy vehicles/day), taken as the polluted site and the other one in a forest approximately 500 m away from the roadside considered as the unpolluted site. Analysis of phylloplane microorganisms, lead, zinc, copper, cadmium and sulphur was carried out from leaves. The bacterial population was higher at the unpolluted site. Bacterial population showed a significant negative correlation with lead, zinc, copper, cadmium and sulphur. Similarly, fungal population was higher at the unpolluted site. A total of 29 fungal species were isolated from the phylloplane of A. nepalensis (polluted site 16 species; unpolluted site 28 species). Some fungal forms like Mortierella sp., Fusarium oxysporum and Aureobasidium pollulans were dominant in the polluted site. Numbers of phylloplane fungi and bacteria were significantly reduced in the polluted site. The correlation coefficient indicated a detrimental effect of metals like lead, zinc, copper, cadmium and sulphur on the microbial community of leaf surfaces. The specificity of certain fungi to the unpolluted site may be attributed to their sensitivity to pollution. The predominance of Aureobasidium pollulans, Fusarium oxysporum and Mortierella sp. in the polluted site may be due to their resistance to pollutants in roadside conditions.

Neonatal exposure to bisphenol A modifies the abundance of estrogen receptor alpha transcripts with alternative 5'-untranslated regions in the female rat preoptic area.

The xenoestrogen bisphenol A (BPA) is commonly ingested by humans. We examined the effects of neonatal exposure to low versus high doses of BPA over the control of estrogen receptor alpha (ERalpha) expression in the preoptic area (POA) of prepubertal female rats. Pups received s.c. injections every 48 h of BPA (high dose, 20 mg/kg and low dose, 0.05 mg/kg) or diethylstilbestrol (DES, 0.02 mg/kg) from postnatal day (PND) 1 to PND7 and were killed at PND8 or PND21. Relative expression of ERalpha transcripts containing alternative 5'-untranslated regions OS, ON, O, OT, and E1 in POA were evaluated by RT-PCR. Methylation status of ERalpha promoters was determined by bisulfited DNA restriction analysis and ERalpha protein by immunohistochemistry. In PND8, the high dose of BPA and DES diminished total ERalpha mRNA levels, mediated by the decreased expression of ERalpha-O and ERalpha-OT variants. In contrast, the low dose of BPA augmented total ERalpha mRNA by increasing the expression of the ERalpha-E1 variant. In PND21, both BPA doses increased total ERalpha mRNA by means of the augmented expression of ERalpha-O and ERalpha-OT variants. In PND21, the methylation status of the ERalpha promoters and the circulating levels of estradiol were similar in all experimental groups. At PND8 and PND21, DES and the high dose of BPA decreased, while the low dose of BPA increased ERalpha protein in the POA. These findings show that neonatal BPA exposure alters the abundance of hypothalamic ERalpha transcript variants and protein in a dose-dependent manner.

[Lichens as rapid bioindicators of pollution and habitat disturbances in the tropics]. / Líquenes como bioindicadores inmediatos de contaminación y cambios medio-ambientales en los trópicos.

Lichens have value as bioindicators of environmental pollution, climate change, and ecological continuity. Extensive work has been undertaken in temperate areas, but in only few cases have the techniques been applied in the tropics. Most tropical studies to date are in relation to air pollution and forest disturbance, but these are scattered geographically and remain to be undertaken in most tropical regions. The potential of lichens as rapid bioindicators in the tropics can start to be realized even where the species described are not fully identified as they are perennial and separable by eye or hand lens, and a lack of training is identified as the main constraint. An extensive bibliography is included.

Sensitization to soybean hull allergens in subjects exposed to different levels of soybean dust inhalation in Argentina.

BACKGROUND: Soybean hulls (SHs) have been identified as the source of aeroallergens responsible for soybean asthma outbreaks. However, the prevalence of sensitization to SH allergens in subjects from Argentina, a country where soybeans are produced, is unknown. OBJECTIVE: The purpose of this study was to determine the prevalence of sensitization to SH by in vivo and in vitro tests in subjects with asthma or allergic rhinitis and in control subjects from Argentina who have been exposed to different levels of soybean dust inhalation (SDI). METHODS: Exposure to SDI is defined as follows: (1) direct = occupational, (2) indirect = proximity to soybean fields or grain elevators, and (3) urban = urbanized areas without a known source of SDI. Two groups were studied. Group 1 consisted of 365 subjects with asthma or allergic rhinitis and group 2 (control group) of 50 healthy individuals. Subjects from both groups were classified according to their exposure to SDI. All subjects completed standard questionnaires. Prick skin tests (STs) with an SH extract and with common allergens were performed on all subjects. Specific IgE and IgG4 to SH were measured in sera of 51 of 56 subjects from group 1 who had a positive ST to SH and in all sera from group 2. RESULTS: Fifty-six (15.3%) subjects from group 1 and no subjects from group 2 had a positive ST to SH (wheal SH/wheal histamine >/=0.5). In group 1, positive STs to SH were 38.7%, 20.3%, and 8.2% in subjects with direct, indirect, and urban exposures, respectively (P <.001). Monosensitization to SH is absent in all subjects from group 1. The percent of subjects with positive STs to mites, pollen, and molds was highest in those with a positive ST to SH versus those with a negative ST to SH (P <.01). Asthmatic patients with a positive ST to SH, compared with those exclusively sensitized to mites, had a higher frequency of daily or weekly symptoms (59.4% vs 25.7%, respectively, P <.001) and a higher percent of glucocorticoid dependence (52.8% vs 34%, respectively, P <.01). Percent positive IgE in group 1 and group 2 were 39.2% and 10% (P <.001) and percents positive IgG4 are 27.4% and 12%, respectively (not significant). In subjects from group 1 and group 2 with direct exposure percents positive IgE are 58.3% and 13.3% (P < .001) and percents positive IgG4 were 75% and 20%, respectively (P < .02). IgG4 in group 1 was significantly higher in subjects with direct exposure compared with subjects with indirect or urban exposure. CONCLUSION: This study demonstrated that there was (1) a high prevalence of sensitivity to SH in subjects with asthma or allergic rhinitis from Argentina and (2) an association between sensitivity to SH and severity of asthma and level of exposure to SDI.

Induction of the lung myofibroblast PDGF receptor system by urban ambient particles from Mexico City.

Platelet-derived growth factor (PDGF) and its receptor system regulate mesenchymal cell proliferation. We recently reported that emission-source fly-ash particles and asbestos fibers induce the PDGF alpha-receptor through a macrophage-dependent pathway, and upregulation of this receptor greatly enhances the mitogenic response of lung myofibroblasts to PDGF (Lindroos and colleagues, Am. J. Respir. Cell Mol. Biol. 1997;16:283-292). In the present study we investigated the effect of particulate matter <= 10 micrometers in size (PM10) from the southern, central, and northern regions of Mexico City on PDGF receptor induction and compared these urban, ambient particles with Mt. St. Helen's volcanic ash particles as a negative control. All Mexico City PM10 samples, but not volcanic ash, stimulated rat alveolar macrophages to secrete a soluble, upregulatory factor(s) for the PDGF alpha-receptor on early passage rat lung myofibroblasts. The macrophage-derived upregulatory activity was blocked by the interleukin (IL)-1 receptor antagonist. The ability of PM10 to stimulate IL-1beta release was blocked in part by a recombinant endotoxin neutralizing protein (rENP). Lipopolysaccharide/endotoxin (LPS) and vanadium, both constituents that were present within these PM10 samples, also stimulated macrophages to secrete factor(s) that upregulated PDGF-Ralpha on lung myofibroblasts. Direct exposure of myofibroblasts to PM10 also elicited upregulation of the PDGF alpha-receptor, and this effect was blocked by rENP and mimicked by LPS, but not vanadium. These findings suggest that PM10 particles induce expression of the PDGF receptor system through macrophage-dependent and -independent mechanisms involving endotoxin and metals.

Changes in human serum antioxidant capacity and peroxidation after four months of exposure to air pollutants.

Twenty-one adult volunteers (aged 27-32 years), who had been living in Mexico City for four continuous months (physicians working as fellows) were studied the first and sixteenth week of their stay in order to learn the effects of the pollutants contained in Mexico City's atmosphere on some serum biochemical parameters. The activity of serum superoxide dismutase (SOD) decreased after 16 weeks in comparison with the values obtained the first week (109.6 to 56.9 mU/mg protein; 50% less). In contrast, the inhibitory capacity of serum vs. induced in vitro lipoperoxidation increased in relation to the length of stay (22%). The serum levels of thiobarbituric-reactive material also decreased in almost 30% (from 6.10 to 4.12 nmol). The other lipoperoxides measured were unchanged (chromolipids and diene conjugation). We propose that this may be as a result of the adaptative capacity of the human organism, within a pollutant atmosphere in which the ozone levels might participate in a decrease of SOD activity during chronic exposure, to air pollution.