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PubMed2006

Carbon and nitrogen composition and stable isotope as potential indicators of source and fate of organic matter in the salt marsh of the Changjiang Estuary, China.

Elemental (TOC, TN, C/N) and stable carbon and nitrogen isotopic (delta(13)C, delta(15)N) compositions were measured for surface sediments, three sediment vibrocores, plants, and suspended particulate matter (SPM) collected from salt marsh of the Changjiang Estuary. The purpose of this study is to characterize the sources of organic matter in sediments and to further elucidate the factors influencing the isotope signature in the salt marsh. Our results indicate that organic matter preserved in the sediments is predominantly controlled by the particulate organic matter in the Changjiang Estuary. The in situ contribution of marsh plants carbon to sediment organic matter is clearest in the high marsh, where the low delta(13)C of the plants (-28.1 per thousand) is reflected by a sediment delta(13)C (-24.7 per thousand) lower than values found for the low marsh and bare flat sediments (-23.4 per thousand and -23.0 per thousand, respectively). The effect of grain size on the spatial difference of isotope composition in the marsh sediments is insignificant, based on the observation that similar isotope values are found in different size particles, both for delta(13)C and delta(15)N. Nutrient utilization by plant assimilation, however, shows great impact on the surface sediment delta(15)N composition, due to the isotope fractionation. With extensive plant coverage and the consequent low surface water nitrate concentration, delta(15)N values of the high marsh surface sediments show (15)N enrichment.

Carbon↗

PubMed2025

Epigenome-Wide Analysis Identifies Pollution-Sensitive Loci in Fibrotic Interstitial Lung Disease.

Rationale: Particulate matter ⩽2.5 μm (PM2.5) adversely impacts patients with fibrotic interstitial lung disease (fILD). Objectives: We sought to determine whether PM2.5-associated epigenetic alterations contribute to the environmental pathogenesis of fILD. Methods: A retrospective two-cohort study applied satellite-derived PM2.5 and constituent exposure matching to the residential location of patients with fILD. Robust linear regressions were used to evaluate cohort-specific, epigenome-wide differential blood DNA methylation with increasing pollutant exposures (Illumina MethylationEPIC BeadChip). Cox and linear regressions were used to evaluate associations of cytosine-phosphate-guanine (CpG) loci with transplant-free survival and lung function. A Wilcoxon test was used to evaluate cartilage-associated protein (CRTAP) levels in fILD and control lungs. Measurements and Main Results: The University of Pittsburgh cohort (n = 306) had 5-year median PM2.5 exposures of 12.1 μg/m3 compared with 5.1 μg/m3 in the University of British Columbia cohort (n = 170). Higher pollutant exposures in the University of Pittsburgh cohort were associated with lower methylation at cg25354716, annotated to CRTAP, a critical extracellular matrix remodeling enzyme. Higher exposures in the University of British Columbia cohort were associated with higher methylation at cg01019301, annotated to TLN2 (talin-2), a cytoskeletal protein involved in fibroblast migration. A 10% increase in cg25354716 methylation was associated with a hazard ratio of 0.81 for death or lung transplantation in the meta-analyzed cohorts (95% confidence interval = 0.69-0.96; P = 0.01), whereas the same change in cg01019301 was associated with a hazard ratio of 1.36 (95% confidence interval = 1.07-1.74; P = 0.01). CRTAP protein was more abundant in lungs from patients with fILD compared with those from donor controls (P < 0.001). Conclusions: PM2.5 is associated with altered blood DNA methylation in fILD. This work identifies novel pollution-sensitive targets that hold potential for therapeutic modulation in fILD.

Humans↗

PubMed2005

Comparison of marine copepod outfluxes: nature, rate, fate and role in the carbon and nitrogen cycles.

We compare the nature of copepod outfluxes of nonliving matter, the factors controlling their rate and their fate, and finally their role, particularly their relative importance in the carbon and nitrogen cycle. Copepods release dissolved matter through excretion and respiration and particulate matter through production of faecal pellets, carcasses, moults, and dead eggs. Excretion liberates several organic C, N, and P compounds and inorganic N and P compounds, with inorganic compounds constituting the larger part. The faecal pellets of copepods are covered by a peritrophic membrane and have a highly variable size and content. There is less information on the nature of other copepod particulate products. The weight-specific rates of posthatch mortality, respiration, excretion, and faecal pellet production have similar C or N levels and are higher than those of moulting and egg mortality. In general, most important factors controlling these rates are temperature, body mass, food concentration, food quality, and faunistic composition. Physical and biological factors govern the vertical fate of copepod products by affecting their sedimentation speed and concentration gradient. The physical factors are sinking speed, advection, stratification, turbulent diffusion, and molecular diffusion. They influence the sedimentation speed and degradation of the copepod products. The biological factors are production, biodegradation (by zooplankton, nekton, and microorganisms) and vertical migration of copepods (diel or seasonal). Physical degradation and biodegradation by zooplankton and nekton are faster than biodegradation by microorganisms. The most important copepod outfluxes are excretion and faecal pellet production. Excretion offers inorganic nutrients that can be directly used by primary producers. Faecal pellets have a more important role in the vertical transport of elements than the other particulate products. Most investigation has focused on carbon burial in the form of copepod faecal pellets, measured by sediment traps, and on the role of ammonia excretion in nutrient recycling. Full evaluation of the role of copepod products in the transport and recycling of elements and compounds requires a quantification of all copepod products and their different fates, particularly detritiphagy, remineralization, and integration as marine snow.

Animals↗

PubMed2002

Electrocardiographic changes during exposure to residual oil fly ash (ROFA) particles in a rat model of myocardial infarction.

Epidemiological studies have reported a positive association of short-term increases in ambient particulate matter (PM) with daily mortality and hospital admissions for cardiovascular disease. Although patients with cardiopulmonary disease appear to be most at risk, particulate-related cardiac effects following myocardial infarction (MI) have not been examined. To improve understanding of mechanisms, we developed and tested a model for investigating the effects of inhaled PM on arrhythmias and heart rate variability (HRV), a measure of autonomic nervous system activity, in rats with acute MI. Left-ventricular MI was induced in 31 Sprague-Dawley rats by thermocoagulation of the left coronary artery; 32 additional rats served as sham-operated controls. Diazepam-sedated rats were exposed (1 h) to residual oil fly ash (ROFA), carbon black, or room air at 12-18 h after surgery. Each exposure was immediately preceded and followed by a 1-h exposure to room air (baseline and recovery periods, respectively). Lead-II electrocardiograms were recorded. In the MI group, 41% of rats exhibited one or more premature ventricular complexes (PVCs) during the baseline period. Exposure to ROFA, but not to carbon black or room air, increased arrhythmia frequency in animals with preexisting PVCs. Furthermore, MI rats exposed to ROFA, but not to carbon black or room air, decreased HRV. There was no difference in arrhythmia frequency or HRV among sham-operated animals. These results underscore the usefulness of this model for elucidating the physiologic mechanisms of pollution-induced cardiovascular arrhythmias and contribute to defining the specific constituents of ambient particles responsible for arrhythmias.

Administration, Inhalation↗

PubMed2006

Partitioning and source diagnostics of polycyclic aromatic hydrocarbons in rivers in Tianjin, China.

Water, suspended particulate matter (SPM), and sediment samples were collected from ten rivers in Tianjin and analyzed for 16 polycyclic aromatic hydrocarbons (PAHs), dissolved organic carbon (DOC), particulate organic carbon (POC) in SPM and total organic carbon (TOC) in sediment. The behavior and fate of PAHs influenced by these parameters were examined. Generally, organic carbon was the primary factor controlling the behavior of the 16 PAH species. Partitioning of PAHs between SPM and water phase was studied, and K(OC) for some PAH species were found to be significantly higher than the predicted values. The source of PAHs contamination was diagnosed by using PAH isomer ratios. Coal combustion was identified to be a long-term and prevailing contamination source for sediment, while sewage/wastewater source could reasonably explain a short-term PAHs contamination of SPM.

Anthracenes↗

PubMed2004

Genotoxicity of environmental air pollution in three European cities: Prague, Kosice and Sofia.

The genotoxic potential of extractable organic matter (EOM) associated with the respirable particulate matter (PM <10 microm) of atmospheric pollution has been determined in three European cities--Prague (Czech Republic, two monitoring sites, Libus and Smíchov), Kosice (Slovak Republic) and Sofia (Bulgaria) using the alkaline single-cell gel electrophoresis (the comet assay). The EOM samples were extracted by dichloromethane from ambient airborne particles collected daily (24 h intervals) during 3-month sampling periods in winter and summer seasons. The human metabolically competent cell line Hep G2 was used as a test system and benzo[a]pyrene (BaP), a known carcinogen, was applied as a positive control (internal standard) in each electrophoretic run. Two-hour exposure of Hep G2 cells to equivalent EOM concentrations ranging from 5 to 150 microg EOM/ml resulted in a linear dose-dependent increase of DNA migration (r > 0.9, P < 0.01). A less significant dose-response (r = 0.61) was only induced by the EOM sample from the locality Prague-Libus (PRG-LB) in the winter. Generally, a 1.5 to four-fold increase of DNA strand breaks over the background control level was determined in EOM-exposed cells. In order to compare the genotoxic potential of individual EOMs, a mathematical model was used to correct the 'real' data. No substantial location- or season-related differences were found in EOM genotoxicity (EOM microg/ml), except for the EOM sample from Sofia, collected in the summer. This EOM sample induced a nearly two-fold lower level of DNA damage in comparison with other EOMs. On the other hand, clear statistically significant location- and season-related differences (P < 0.001) in ambient air genotoxicity were determined when the EOM quantity per cubic meter of air (microg/m3) was taken into account. In that case, the genotoxicity of winter air pollution was six- to 10-fold higher in comparison with summer air. The air pollution genotoxicity in individual localities rose during the winter season in the order: PRG-LB < Kosice < Prague-Smíchov (PRG-SM) < Sofia, while during the summer season the highest ambient air genotoxicity was revealed in the locality Prague-Smíchov and approximately equal air pollution genotoxicity was determined among localities Prague-Libus, Kosice and Sofia (PRG-LB approximately Kosice approximately Sofia < PRG-SM). The greatest overall air pollution genotoxicity was determined in the locality Sofia during the winter season. In a time course study to evaluate the kinetics of DNA strand break rejoining it was shown that the level of DNA strand breaks in EOM-exposed cells has returned to near the background level within 24 h after the treatment.

Air Pollutants↗

PubMed2001

Increase in inhalable particulates' concentration by commercial and industrial activities in the ambient air of a select Indian metropolis.

Inhalable particulates (particulates less than 10 micron) present in ambient air find passage into the respiratory system due to their small size and impair the health. Surveillance of inhalable particulates is, therefore, essential for assessing an inhalation health hazard. The activity also provides guidance for appropriate protection against the ill effects. Monitoring of inhalable particulates requires a high-volume sampler retrofitted with a size selective inlet (SSI) to separate and sample specified size-range fractions of suspended particulate matter in air. Measurement of inhalable particulates indirectly represents anthropogenic activity. In view of this, surveillance of inhalable particulates was conducted in select metropolitan cities of India during 1995-1997 to find out changes in their concentration. The inhalable particulates were measured by retrofitting a suitably designed SSI to the standard high-volume sampler. The study revealed that the concentration of inhalable particulates in the ambient air increased due to industrial activities up to 320, 168, and 546% and due to commercial activities up to 406, 198, and 140% in Ahmedabad, Mumbai, and Delhi, respectively. An increase in inhalable particulates' concentration during the above period also showed a marked seasonal variation. The increase due to commercial activity, however, did not show a definite tendency.

Air Pollution↗

PubMed2002

Evaluation of artificial neural networks for fine particulate pollution (PM10 and PM2.5) forecasting.

Multi-layer perceptron (MLP) artificial neural network (ANN) models are compared with traditional multiple regression (MLR) models for daily maximum and average O3 and particulate matter (PM10 and PM2.5) forecasting. MLP particulate forecasting models show little if any improvement over MLR models and exhibit less skill than do O3 forecasting models. Meteorological variables (precipitation, wind, and temperature), persistence, and co-pollutant data are shown to be useful PM predictors. If MLP approaches are adopted for PM forecasting, training methods that improve extreme value prediction are recommended.

Air Pollutants↗

PubMed1995

Quality of cefotaxime sodium preparations.

Cefotaxime sodium (CAS 64485-93-4) is a semisynthetic cephalosporin derivative belonging to the third-generation cephalosporins. Owing to its broad antibacterial activity and its high resistance to beta-lactamases it can be used for a large variety of infections. In the present study the quality standard of 15 different cefotaxime sodium manufacturers from 9 different countries has been examined. The best results were received for the preparation Claforan. None of the 14 other products showed comparable results especially with respect to particulate matter and by-products. The particulate contamination of the 14 foreign products showed relatively high values although they still comply with the limits set by the pharmacopoeias. In contrast, in Claforan very few particles were found in the solution. This is of importance as the drug has to be administered either i.v. as an infusion or i.m. as an injection. Also the amount of by-products measured in the 14 foreign preparations was about 1.5 times higher than the one measured for Claforan. Although these are not critical results, they do indicate that there are marked differences between the quality of the products from different countries which should be taken into account.

Acetates↗

PubMed2004

Dynamics of particulate major and trace elements in the lower reaches of the Daugava River and adjacent area of the Gulf of Riga (Baltic Sea).

Suspended particulate matter (SPM) was collected in the freshwater-seawater mixing zone in the lower reaches of the Daugava River (Latvia) and adjacent marine area, during five cruises in 1998-2001. The study focused on biogeochemical phase exchange processes. SPM in the freshwater was found to be mainly allochthonous with a high content of organic matter, Mn and sorbed phosphate. Property-salinity plots suggested flocculation of humic-Fe complexes across the salinity gradient. The variability of sorbed phosphate was related to particulate Fe, although no dependence on pH and ionic strength was observed. The Mn contents of SPM mainly follow conservative mixing, but there are also indications of interface exchange of Mn in the mixing zone. The geochemical behaviour of particulate Al appears to differ from that of Fe. In early spring, trace element contents in SPM (Cr, Ni, Cu, Zn, Cd, Pb) correlate tightly with particulate organic matter, whose distribution is linked to phytoplankton distributions.

Baltic States↗

PubMed2004

Gaseous and particulate air pollution in the Lanzhou Valley, China.

Gaseous and particulate matter measurements were performed from January 1999 to December 2001 to assess seasonal and diurnal patterns of air pollutions in the Lanzhou Valley, China. The objectives are the determination of the temporal variability of total suspended particulate (TSP) matter and PM10 levels, and their relationship with the SO2 and NOx emissions and desert dust intrusions from the dust sources in the Hexi Corridor in Gansu Province. The results showed that concentrations of gaseous and particulate pollutants undergo seasonal variations characterized by a winter maximum levels for SO2 (0.094-0.208 mg/m3) and NO2 (0.068-0.089 mg/m3) and a spring maximum levels for TSP (0.885-1.037 mg/m3). Linear regression analysis indicated that the diurnal mean TSP/PM10 ratio may approximate to 3.0, and that the annual NO2/NOx ratio was approximately 0.86, with its highest monthly average of 0.91 in June and its lowest monthly average of 0.788 in January. The origin of PM10 episodes was investigated by correlating the PM10 episodes in the Lanzhou Valley with the high wind speeds in Jinchang (dust sources) in the Hexi Corridor, and also, by comparing the PM10 levels with the SO2 and NOx concentrations. Most of the 'high PM10 episodes' (1-h mean maximum >1.0 mg/m3) were attributed to the desert dust intrusions from the Hexi Corridor. The influence of the industrial and domestic emissions in the PM10 levels was evidenced during most of the periods with the PM10 levels less than 1.0 mg/m3.

Journal Article↗

PubMed1996

Induction of prostaglandin H synthase 2 in human airway epithelial cells exposed to residual oil fly ash.

Exposure to ambient air containing respirable particulate matter at concentrations below the current National Ambient Air Quality Standard has been associated with increased rates of pulmonary-related morbidity and mortality. To identify mechanisms involved in pulmonary responses to such exposure, we studied the effects of the emission source particulate air pollutant residual oil fly ash (ROFA) on prostaglandin metabolism in cultured human airway epithelial cells. Epithelial cells exposed to ROFA for 24 hr secreted substantially increased amounts of the prostaglandin H synthase (PHS) products prostaglandins E2 and F2 alpha. The ROFA-induced increase in prostaglandin synthesis was correlated with a marked increase in PHS activity. Western blots showed that ROFA exposure induced dose-dependent increases in PHS2 protein levels. Reverse transcriptase-PCR analyses demonstrated accompanying increases in PHS2 mRNA which were evident by 2 hr of continuous exposure. In contrast, expression of PHS1 was not affected by ROFA treatment of airway epithelial cells. There were no alterations in arachidonic acid release, incorporation, or availability in ROFA-exposed cells. These data show that exposure to ROFA induces PHS2 expression, leading to increased prostaglandin synthesis in cultured airway epithelial cells. These findings suggest that prostaglandins may play a role in the toxicology of air pollution particle inhalation.

Air Pollutants↗

PubMed2006

Multivariate statistical analysis of meteorological and air pollution data in the 'Campo de Gibraltar' region, Spain.

A complete statistical analysis of meteorological and air pollution data was carried out in the 'Campo de Gibraltar' region (in the South of Spain) from 1999 to 2002. This is a heavy industrialized area where, up to date, very few air pollution studies have been made. The main objectives of the study presented here have been the characterization of the meteorological and (gaseous and particulate) air pollution conditions in the area, and the relations between them. Multivariate statistical techniques, such as Principal Component Analysis (PCA), have been applied to the data. The results show that air quality in the area is highly dependent on meteorological conditions such as wind persistence and direction, dispersion capability of the atmosphere, and humidity content. On average, sulphur dioxide and nitrogen oxide air pollution, mainly caused by fuel-oil combustion and traffic, respectively, is not very high. However, an important number of exceedences of the limits established by the EU Directive 1999 for PM10 (particulate matter with a diameter less than 10 microm) have been observed in some points of the area. A significant percentage of these exceedences (about 22% on average) are likely caused by African dust intrusions, which usually take place from May to August. From gaseous and particulate air correlations, it seems that anthropogenic activities contribute with about 19% on average.

Air Pollutants↗

PubMed2003

Responses of cultured human airway epithelial cells treated with diesel exhaust extracts will vary with the engine load.

Epidemiologic evidence suggests that increased morbidity and mortality are associated with the concentrations of ambient air particulate matter (PM). Many sources contribute to the particulate fraction of ambient air pollution, including diesel exhaust particulates (DEP). Diesel exhaust also contributes gas-phase pollutants to the atmosphere, and gaseous copollutants may influence the toxicity of PM. The composition of diesel exhaust varies greatly depending on the engine load conditions as well as other factors. To determine whether different diesel exhaust composition can affect lung cell resposes, the effects of of diesel exhaust extracts derived from different engine loads were examined on normal human bronchial epithelial cells (NHBE) in vitro. Diesel exhaust was collected into chilled impingers containing phosphate-buffered saline (PBS). Cultured NHBE cells were treated with 0 to 500 microg/well extract from approximately 0% engine load (termed low load or LL) or extract from approximately 75% engine load (termed high load or HL) for 24 h. The HL extract was cytotoxic at 500 microg compared to controls as measured by (51)Cr release. Production of the neutrophil chemotaxin interleukin 8 (IL-8) was decreased 4.7-fold in cells treated with 500 microg LL extract, whereas cells treated with 500 microg HL extract showed a 2.4-fold increase in IL-8 release. Production of the inflammatory and immune system mediator prostaglandin E(2) (PGE(2)) was increased up to 2.5-fold in cells treated with HL extract, but unchanged with other treatments. Melittin stimulation of cells showed that the LL extract had an inhibitory effect on PGE(2) release at 500 microg. Differences in carbonyl content of the extracts were found by high performance liquid chromatography/mass spectroscopy HPLC/MS, with the HL extract having more intermediate size carbonyls (i.e. with six to nine carbons). The data suggest that the response of NHBE cells to treatment with diesel exhaust will vary depending on the constituent components of the exhaust.

Air Pollutants↗

PubMed1983

Estimating the hazards of "less hazardous" cigarettes. III. A study of the effect of various smoking conditions on yields of hydrogen cyanide and cigarette tar.

A brand of cigarette with nominal tar and nicotine yields of 4.0 mg and 0.4 mg, respectively, was examined under various machine-smoked conditions that reflect the wide range of human smoking behavior. Three levels of each of five smoking parameters--butt length, puff duration, puff interval, puff volume, and ventilation occlusion--were examined, and the effects on puff number and total particulate matter (TPM) as well as gas phase, particulate phase, and total HCN yields were estimated. Yields of hydrogen cyanide (a ciliatoxic agent) and TPM varied significantly under different smoking conditions. Ventilation occlusion had the most pronounced effect, accounting for 34% of the response variation of TPM yields and 42% of the response variation for total hydrogen cyanide yields. In the survey of available brands, total hydrogen cyanide yields varied from 2 to 233 micrograms/cigarette for the 115 brands tested, a range less than that observed for a single brand smoked under various nonstandard conditions, providing a possible explanation for the previously noted lack of correspondence between HCN yields under standard conditions and levels of thiocyanate in samples of smokers' plasma and saliva. In addition, hydrogen cyanide yields and efficiency of filters in removing HCN were examined under standard smoking conditions. Acetate filters, the most common variety, were found to remove an average of about 14% of the hydrogen cyanide from the mainstream smoke.

Analysis of Variance↗

PubMed1980

Enrichment and association of bacteria and particulates in salt marsh surface water.

Elevated counts of bacteria were found during outgoing tides in surface microlayers ( approximately 300 mum) of Sippewissett salt marsh, Falmouth, Massachusetts, and Palo Alto salt marsh, Palo Alto, California. At both sampling sites, the degrees by which bacteria were concentrated into the surface microlayer were linearly dependent upon surface concentration of particulate material. A significant percentage of bacteria in the microlayer were found to be attached to particulate material, while bacterial populations in the subsurface water were largely planktonic. Proportions of the bacterial populations which could be grown on seawater nutrient agar were also greater in the microlayer than in the subsurface waters and were positively correlated with the fraction of bacteria attached to particulate matter. Data from these studies suggest that particulates in the microlayer waters of the salt marsh influenced the observed increase in both the readily grown and the total numbers of bacteria.

Journal Article↗

PubMed2001

Air pollution particles mediated oxidative DNA base damage in a cell free system and in human airway epithelial cells in relation to particulate metal content and bioreactivity.

Epidemiological studies demonstrate an association between increased human morbidity and mortality with exposure to air pollution particulate matter. We hypothesized that such effects may be associated with the ability of the particles to mediate generation of reactive oxygen species (ROS), either directly, via interaction with ambient oxygen or indirectly through initiation of an oxidative burst in phagocytes. To test this hypothesis, we determined 8-oxo-dG formation as a measure of direct generation of ROS, in response to particulate exposures to 2'-deoxyguanosine (dG), free and in calf thymus DNA in aerated solutions as the target molecule and cell culture, to assess the relationship between induction of oxidative damage, particulate metal content and metal bioreactivity. The HPLC-ECD technique was employed for separation and quantification of 8-oxo-dG, the most widely recognized marker of DNA oxidation. Particles used in this study include: Arizona desert dust (AZDD), coal fly ash (CFA and ECFA), oil fly ash (OFA and ROFA), and ambient air [SRM 1649 and Dusseldorf (DUSS), Germany]. The major difference between these particles is the concentration of water-soluble metals. The fly ash particulates OFA and ROFA showed a significant dose-dependent increase in dG hydroxylation to 8-oxo-dG formation over the control dG (p < 0.05), with yields 0.03 and 1.25% at the highest particulate concentration (1 mg/mL). Metal ion chelators and DMSO, a hydroxyl radical scavenger, inhibited this hydroxylation. In contrast, desert dust, coal fly ash and urban air particles induced 8-oxo-dG with yields ranging from 0.003 to 0.006%, respectively, with levels unaffected by pretreatment of the particles with metal ion chelators or addition of DMSO to the incubation mixture. When calf thymus DNA was used as a substrate, all the particles induced 8-oxo-dG in a pattern similar to that observed for dG hydroxylation, but with relatively less yield. Treatment of the particles with metal ion chelator before reacting with DNA or addition of catalase in the incubation mixture, suppressed 8-oxo-dG formation significantly (p < 0.05) in oil-derived fly ash particles only. To determine whether the oxidative responses of these particulates as shown in cell-free systems were consistent with responses using a more biologically relevant environment, human airway epithelial cells were treated with the particulates and induction of 8-oxo-dG was determined. All particles induced 8-oxo-dG in the DNA of cells above culture control, except CFA. Cells exposed to 10-400 mg/mL of ROFA for 2 h induced a dose-dependent increase in 8-oxo-dG formation. Treatment of ROFA with metal ion chelator attenuated these effects. Overall, damage enhancement by particulates in dG, calf thymus, and cellular DNA as determined by 8-oxo-dG formation under aerobic conditions is consistent with the concentration of water-soluble, not the total metal content of the particle.

8-Hydroxy-2'-Deoxyguanosine↗

PubMedDate not supplied

Increased expression of cyclooxygenase 2 mediates oil fly ash-induced lung injury.

We have previously shown that in vitro exposure to the combustion-derived ambient air pollutant residual oil fly ash (ROFA) induces the expression of prostaglandin H synthase 2 (COX2) in human airway epithelial cells. To determine the role of prostaglandins and COX2 expression in ROFA-induced lung injury in vivo, we have examined the effect of intratracheal ROFA instillation on COX2 expression, prostaglandin synthesis, and indices of pulmonary injury and inflammation in adult Sprague-Dawley rats. ROFA treatment induced a marked increase in the level of prostagladin E2 (PGE2) recovered in the bronchoalveolar lavage fluid (BALF), which was effectively decreased by pretreating the animals with the specific COX2 inhibitor NS398. Immunohistochemical analyses of rat airways showed concomitant expression of COX2 in the proximal airway epithelium of rats treated with ROFA. Increases in BALF protein, but not interleukin 6 (IL-6) increases or ROFA-induced polymorphonuclear neutrophils (PMN) influx into the airway, were blunted by administration of NS398 prior to ROFA instillation. These data demonstrate that prostaglandins mediate lung injury induced by exposure to ROFA and implicate increased expression of COX2 as a mechanism that contributes to the toxicity of metal-laden ambient particulate matter.

Air Pollutants↗