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Results for “NITROGEN DIOXIDE”

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PubMed1993

Desferrioxamine treatment reduces histological evidence of lung damage in rats after acute nitrogen dioxide (NO2) intoxication.

1. In previous studies a rat inhalation model was developed to investigate the efficacy of treatment in acute NO2 intoxication. 2. Desferrioxamine was administered intravenously to study its effect on histological alterations in lung tissue in rats after acute NO2 exposure. 3. Twenty four hours after exposure to 175 ppm NO2 for 10 minutes the lung injury observed by light microscopy in the desferrioxamine treated rats was less pronounced than in the saline treated rats. 4. Desferrioxamine appeared to provide more protection with a dose of 100 mg kg-1 24 h-1 than with 200 mg kg-1 24 h-1.

Administration, Inhalation↗

PubMedDate not supplied

Biochemical changes in rat lungs after exposure to nitrogen dioxide.

Sixty-day-old male, specific pathogen-free rats were exposed continuously to 5 or 15 ppm NO2 for 1-7 d. Lung tissue from exposed and control rats was then analyzed for biochemical and enzymatic parameters. The exposure resulted in increased lung enzymatic activities, including elevated protein and DNA contents and nonprotein sulfhydryl levels. Biochemical and enzymatic parameters generally increased maximally after 4 d and remained elevated for up to 7 d of continued exposure. The magnitude of these increases was higher for 15 than for 4 ppm NO2. The increases in biochemical and enzymatic parameters may have occurred in response to NO2-induced lung injury.

Animals↗

PubMed1991

[A comparative evaluation of the methods for determining nitrogen dioxide in an industrial environment].

The present work has the purpose to make a comparative evaluation of the different types detector tubes--for analysis, long-term and passive for determination of NO2 and the results to be compared, with those received by the spectrophotometric method and the reagent of Zaltsman. Studies were performed in the hall of the garage for repair of diesel buses during one working shift. The results point out that the analysing tubes for NO2 give good results with the spectrophotometric method. The measured average-shift concentrations of NO2 by long-term and passive tubes are juxtaposed with the average-received values with the analytical tubes and with the analytical method.

Air Pollutants, Occupational↗

PubMedDate not supplied

[Nitrogen dioxide in the environmental air as a precursor of endogenous synthesis of carcinogenic nitrosamines].

The experiment was conducted on white noninbred rats receiving different concentrations of the nitrosamine (NA) precursors NO2 and amidopyrinum. Carcinogenic NAs were determined in the organs of the animals that had inhaled them at concentrations of 0.4, 0.8, and 4.0 mg/m3. There was an increase in tumors in chronic experiments on exposure to NA in the same doses as compared with the controls. It was found that the ambient air NO2 level of 0.4 mg/m3 (MAC 10 mg/m3) should be considered to be hazardous due to the fact that there might be exogenous and endogenous syntheses and that the NA might exert a carcinogenic effect.

Animals↗

PubMed1989

Spleen cellularity shifts from the inhalation of 0.25-0.35 PPM nitrogen dioxide.

The effects of ambient level (0.25-0.35 ppm)NO2 on percent spleen cell counts, relative percentages of spleen lymphocyte subpopulations, spleen lymphoid nodule size, and differential peripheral blood cell counts were investigated in 170 young adult male mice following various NO2 exposure periods. The total spleen cell counts, surface IgM-positive lymphocytes and spleen mean lymphoid nodule area were all significantly decreased in the groups exposed to NO2 following extended time periods. The relative percentages of peripheral blood lymphocytes were also significantly decreased in the groups exposed to NO2 for 8 weeks. The mechanism for these observed spleen changes following ambient level NO2 exposure remains unclear, but the results warrant further investigation and concern, especially since such changes may reflect altered immune responsiveness.

Animals↗

PubMed2004

A field evaluation of a piezo-optical dosimeter for environmental monitoring of nitrogen dioxide.

Measurements of 8-hour time-weighted average NO(2) concentrations are reported at 7 different locations in the region of Dunkirk over 5 consecutive days using PiezOptic monitoring badges previously calibrated for the range 0-70 ppb together with data from chemiluminescent analysers in 5 sites (4 fixed and one mobile). The latter facilities also provided data on ozone and NO concentrations and meteorological conditions. Daily averages from the two pairs of badges in different types of sampling cover in each site have been compared with data from the chemiluminescent analysers, and found largely to agree within error margins of +/-30%. Although NO(2) and ozone concentrations were low, rendering detailed discussion impossible, the general features followed expected patterns.

Air Pollutants↗

PubMed1990

Exposure of pulmonary artery endothelial cells to nitrogen dioxide activates phospholipase A1.

Phospholipase A1, A2, and C and diacylglycerol lipase activities were measured in cell sonicates after exposing confluent monolayers of porcine pulmonary artery endothelial cells to 5 ppm NO2, a toxic constituent of environmental pollution, for 24 and 48 hr. There was a significant increase (2.25-fold) in phospholipase A1 activity in 24 and 48 hr NO2-exposed cells, whereas activities of phospholipases A2 and C and diacylglycerol lipase were comparable to control cells at both time points. When endothelial cells were prelabeled with [3H]-arachidonic acid and then exposed to NO2 for 48 hr, increased counts were recovered from cell lysophospholipids with concomitant decreased recovery of counts from cell phosphatidylcholine and phosphatidylethanolamine. These results demonstrate that NO2 exposure results in specific activation of phospholipase A1.

Animals↗

PubMed1999

Effect of beta-carotene on the transformation of tyrosine by nitrogen dioxide and peroxynitrous acid.

In the NO2-exposure of tyrosine in 70% dioxane/phosphate buffer (pH 7.4), beta-carotene enhanced the degradation of tyrosine and/or 3-nitrotyrosine produced, whereas alpha-tocopherol and ascorbyl palmitate inhibited the transformation of tyrosine into 3-nitrotyrosine. Generation of certain active species in the interaction of beta-carotene with NO2 was suggested. Ascorbyl palmitate effectively and alpha-tocopherol slightly inhibited the transformation of tyrosine in the NO2-exposure in the presence of beta-carotene. In the reaction of tyrosine with ONOO-/ONOOH, beta-carotene enhanced the degradation of 3-nitrotyrosine produced suggesting generation of certain active species, whereas alpha-tocopherol and ascorbyl palmitate completely suppressed the transformation of tyrosine into 3-nitrotyrosine.

Ascorbic Acid↗

PubMed1984

Changes of cardiac and respiratory rhythm in non- and tracheostomized rats exposed to nitrogen dioxide.

Cardiac and respiratory changes in non- and tracheostomized rats were examined during exposure to 20 ppm of NO2 for 150 min. The abnormal respiratory pattern consisted of rapid shallow breathing, deep breathing, and apnea, and the bradyarrhythmias were observed in the tracheostomized rats during exposure. Also, similar changes were seen in the nontracheostomized rats. A decrease in the heart rate (HR) was observed in both non- and tracheostomized rats. The decrease in HR was depressed by atropine injection, and the abnormal respiratory patterns were almost abolished by this drug. It was suggested, from these results, that the cardiac and respiratory abnormalities could be induced without the irritation to upper respiratory tracts, and that the vagal efferent pathway had an important role in the appearance of the abnormalities during exposure.

Air Pollutants↗

PubMed1981

Biosynthesis of dimethylnitrosamine in dimethylamine-treated mice after exposure to nitrogen dioxide.

These studies demonstrate the nitrosating potential of NO2 in vivo in ICR mice. Groups of mice were gavaged with 2 mg dimethylamine (DMA) and exposed to NO2 at levels from 0.04 to 44.5 ppm for periods up to 4 hours. Mice were individually frozen and blended to a powder, aliquots of which were homogenized in ice-cold dicholoromethane and 35% aqueous methanol. Concentrates of organic extracts were analyzed or dimethylnitrosamine (DMN) by a Thermal Energy Analyzer with a gas chromatograph interface. Biosynthesis of DMN was dose- and time-dependent with relation to NO2 exposure, reaching a maximum yield of 60-70 ng/mouse (0.0035% DMA conversion) at 2 hours. DMN biosynthesis was inhibited by sodium ascorbate and, more effectively, by ammonium sulfamate.

Animals↗

PubMed2000

The nitration of pyrene adsorbed on silica particles by nitrogen dioxide.

Conversion of NO2, HNO2 gas, their mixture and a mixed gas of HNO2 and HNO3 on silica particles was investigated under simulated atmospheric conditions. Both HNO2 and HNO3 were detected as the products from conversion of NO2 on silica particles. However, unlike HNO3, which increased with conversion time, HNO2 underwent an increase-decrease time course due to the increased HNO3 further transformed HNO2 into NO+ on silica particles. Considering the catalytic effect of HNO3 and HNO2 on the nitration of pyrene adsorbed on silica particles by NO2, another electrophilic nitration path, analogous to the one that we previously reported, with NONO2+ and NON2O4+ as electrophiles was suggested. The two paths together gave an appropriate explanation for the catalytic effect of HNO2, HNO3 and their mixed gas on the nitration of the adsorbed pyrene by NO2.

Adsorption↗

PubMed1977

Comparison of three instrumental methods to monitor nitrogen dioxide.

Three commercially available automated NO2-monitors, based on amperometry, chemiluminescence and coulometry respectively, were compared under simulated field conditions over a period of 45 days of continuous operation. The main purpose of this programme was the study of the reliability of the overall system, sampling line-monitors-data acquisition and handling system (PDP-8/E), the correlation between the individual half-hour averages given by the three monitors in the range 0--700 mug NO2/m3 and the comparison of the global statistics for the same NO2-pollution simultaneously seen by the three different monitors over a period of 45 days. Based on more than 1200 valid half-hour averages, a highly significant correlation between the different monitors was obtained, while the statistics of the simulated NO2-pollution were in good agreement.

Air Pollutants↗

PubMed1999

Development of a personal monitoring method for nitrogen dioxide and sulfur dioxide with Sep-Pak C18 cartridge sampling and ion chromatographic determination.

Personal monitoring methods for the determination of hourly integrated concentrations of NO2 and SO2 in ambient air have been developed. Triethanolamine (TEA)-impregnated C18 Sep-Pak cartridges were used to collect NO2 and SO2 simultaneously. After sampling, NO2 and SO2 as their nitrite, nitrate, sulfite and sulfate analogues were stripped from the cartridges with a solution of 5% methanol in distilled, deionized water (DDW) and then determined by ion chromatography. Laboratory tests were conducted to evaluate the sampling rate, collection and recovery efficiencies, breakthrough volumes, absorption capacity, interference and sample stability on the cartridge during storage. NO2 and SO2 detection limits of 0.3 and 0.4 ppb respectively for 1 h samples were obtained. Recoveries for both NO2 and SO2 exceeded 85%.

Air Pollutants↗

PubMed1990

Nitro reaction in mice injected with pyrene during exposure to nitrogen dioxide.

We have previously reported that the beta-glucuronidase-treated urine of mice injected intraperitoneally with pyrene during exposure to NO2 contained highly mutagenic compounds such as nitropyrene metabolites when tested by the Ames assay using Salmonella typhimurium strain TA98. In the present study, we found that the formation of these mutagens was dose-dependent between 10 and 200 mg of pyrene per kg of body weight at 5 and 10 ppm of NO2. Further, to elucidate the substrate of nitration in vivo, we injected 1-hydroxypyrene, which is the metabolite of pyrene, to mice intraperitoneally during exposure to NO2. Since the results were the same as those obtained by injection with pyrene, we suggest that the pyrene was not nitrated directly but after its hydroxylation.

Animals↗

PubMed2001

Dietary uptake of lycopene protects human cells from singlet oxygen and nitrogen dioxide - ROS components from cigarette smoke.

There is current interest in the health benefits of dietary carotenoids and the possible deleterious effects on certain sub-populations such as smokers. Here we report in vivo protection of human lymphocytes, conferred by dietary supplementation of lycopene rich foods against the reactive oxygen species, NO(2)(*) radical (by electron transfer) and 1(O)(2) (by energy transfer). It was found that a lycopene rich diet, maintained for 14 days, increased the serum lycopene level 10 fold compared to serum obtained after the same period, where a typical western European diet had been consumed. Relative lymphocyte protection factors of 17.6 and 6.3 against NO(2)(*) radical and 1(O)(2), respectively, were obtained, which re-enforce epidemiological data, showing protection against several chronic diseases by tomato lycopene.

Antioxidants↗

PubMed1980

Effect of acute nitrogen dioxide exposure on the composition of fatty acids in lung and liver phospholipids.

In order to examine the effects of NO2 on the fatty acid content of the lung and liver phospholipids, the phospholipid fractions of rats exposed to 20 ppm NO2 for 20 and 40 h were extracted and analyzed using gas chromatography. Among the ftty acid species in the lung, the relative amount of palmitic acid, palmitoleic acid and linoleic acid increased significantly, whereas myristic acid, stearic acid and oleic acid decresed significantly after exposure to NO2. These changes in the composition of fatty acids are discussed in comparison with the results of acute, subacute and chronic exposure to NO2 reported by other workers. In the case of the fatty acid species in the liver, a significant increase for stearic acid and arachidonic acid and a decrease in oleic acid were observed.

Animals↗

PubMed2000

Impact of microenvironmental nitrogen dioxide concentrations on personal exposures in Australia.

Indoor and outdoor NO2 concentrations were measured and compared with simultaneously measured personal exposures of 57 office workers in Brisbane, Australia. House characteristics and activity patterns were used to determine the impacts of these factors on personal exposure. Indoor NO2 levels and the presence of a gas range in the home were significantly associated with personal exposure. The time-weighted average of personal exposure was estimated using NO2 measurements in indoor home, indoor workplace, and outdoor home levels. The estimated personal exposures were closely correlated, but they significantly underestimated the measured personal exposures. Multiple regression analysis using other nonmeasured microenvironments indicated the importance of transportation in personal exposure models. The contribution of transportation to the error of prediction of personal exposure was confirmed in the regression analysis using the multinational study database.

Adult↗

PubMed1985

Indoor air pollution and its effect on pulmonary function of adult non-smoking women: I. Exposure estimates for nitrogen dioxide and passive smoking.

The potential effects of indoor NO2 and tobacco smoke on the respiratory system were studied using pulmonary function data from a longitudinal study. In 1982, NO2 was measured in 163 homes of non-smoking adult women and detailed information on smoking inside the house was gathered over the period 1965-1982. Personal exposure to NO2 was calculated from the measured levels and the activity pattern of the study population (range 11-139 micrograms NO2/m3). Historical exposure was estimated using regression models of NO2 on house characteristics. It is shown that estimation of historical exposure to indoor NO2 on the basis of house characteristics only is, at present, too inaccurate for use in epidemiological studies. Actual measurement of NO2 is unavoidable for exposure assessment in health effect studies of indoor exposure to NO2.

Adult↗