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PubMed2005

Immunochemical detection of nitric oxide and nitrogen dioxide trapping of the tyrosyl radical and the resulting nitrotyrosine in sperm whale myoglobin.

We demonstrate herein that nitric oxide (*NO) and nitrogen dioxide (*NO2) both react with the tyrosyl radical formed in sperm whale myoglobin (swMb) by reaction with hydrogen peroxide. The tyrosyl radical was detected by Western blotting using a novel anti-5,5-dimethyl-1-pyrroline N-oxide (DMPO) polyclonal antiserum that specifically recognizes protein radical-derived DMPO nitrone adducts. In the presence of DMPO, hydrogen peroxide reacts with swMb to form the DMPO tyrosyl radical as is known from both electron spin resonance and immuno-spin trapping investigations. Both *NO and NO2- significantly suppressed DMPO-Mb formation under the physiological oxygen tension of 30 mm Hg. If this inhibition of DMPO trapping of the tyrosyl radical is due, at least in part, to the reaction of the tyrosyl radical with *NO and *NO2, then nitrotyrosine should be formed. In line with this expectation, swMb treated with low concentrations of *NO or NO2- formed nitrotyrosine when hydrogen peroxide was added under 30 mm Hg oxygen tension as detected by Western blotting. The amount of nitrotyrosine generated with *NO was higher than with NO2-, implying that there are two different peroxynitrite-independent nitrotyrosine formation mechanisms and that *NO is not just a source of *NO2.

Aerobiosis↗

PubMedDate not supplied

Exposure to nitrogen dioxide (NO2) and respiratory disease risk.

Epidemiological evidence suggests that exposure to nitrogen dioxide (NO2) through the use of unvented gas cookers in homes is associated with respiratory symptoms. Toxicological evidence, mainly in animal models, suggests that NO2 may increase the susceptibility to infection by viruses and bacteria. This review examines the evidence and proposes mechanisms whereby such exposure may occur, in particular how NO2 may aggravate respiratory symptoms in the presence of coexistent infection.

Adult↗

PubMed1981

Effect of acute nitrogen dioxide exposure on the prostacyclin synthesis in lung.

The effect of acute nitrogen dioxide (NO2) exposure on prostacyclin synthesis in the rat lung was studied. Male Wistar rats were exposed to 5, 10, 15, 20 and 25 ppm NO2 for 24 h. Dose-dependent decrease in prostacyclin-synthesizing activities of both homogenized and intact lung was observed. This decrease in prostacyclin synthesis following NO2 exposure may be related to formation of lipid peroxides due to NO2 exposure and to damage of pulmonary epithelial cells and endothelial cells by NO2 exposure.

Air Pollutants↗

PubMed1984

Indoor nitrogen dioxide pollution and respiratory symptoms of schoolchildren.

The influence of indoor nitrogen-dioxide exposure on respiratory symptoms of schoolchildren was investigated in a case-control study. The election method used was useful in obtaining symptomatic children, but insufficient in defining cases and controls without additional information. No relationship between indoor NO2 and respiratory symptoms was found. Bias may have been present, especially because of the high mobility of the study population. Attempts to estimate historical exposure were inaccurate. Therefore the results do not exclude that an association between indoor NO2 and respiratory symptoms exists.

Air Pollutants↗

PubMed2004

Street-level concentrations of suspended particulate matter (SPM), nitrogen dioxide (NO2) and sulphur dioxide (SO2) in Pune City.

The concentration of suspended particulate matter (SPM), nitrogen dioxide (NO,) and sulphur dioxide (SO2) were measured at 13 important traffic intersections in Pune city. In order to study the contribution of these pollutants from motor vehicles, attention was focused on the roadside, street-level concentration. The statistical analysis of the sampling results indicates that there is not only high correlation between SPM and NO2 but the levels of these pollutants are above the National Ambient Air Quality Standards (NAAQS) laid down by the Central Pollution Control Board (CPCB), India. The SO, concentrations are found to be well below the NAAQS.

Air Pollutants↗

PubMedDate not supplied

A study of respiratory illnesses in infants and nitrogen dioxide exposure.

Toxicologic and epidemiologic studies have elevated concern that exposure to nitrogen dioxide (NO2) in outdoor and indoor air may increase the frequency and severity of respiratory infections. We have developed and implemented a prospective cohort study to test the hypothesis that exposure to NO2 increases the incidence and severity of respiratory infections during the first 18 mo of life. This study, which was based on extensive pilot research, was designed to address the potential limitations of misclassification, confounding, and inadequate power. Enrollment of 1,315 subjects has been completed. This paper reviews the methods used in the study, characteristics of the enrolled subjects, NO2 concentrations in the homes of study participants, and rates of illness occurrence.

Air Pollution, Indoor↗

PubMed1981

A quantitative study of ciliary injury in the small airways of mice: the effects of nitrogen dioxide.

The frequency and types of abnormal cilia prior to and following nitrogen dioxide (NO2) exposure in the small airways of an inbred strain of mice was quantitated by transmission electron microscopy. Age-matched male and female mice were exposed to 20 ppm NO2 for 28 days. In both sexes, exposures to NO2 resulted in a significant increase (P less than 0.01) in abnormal cilia characterized by (1) decreased number of ciliary structures on cell surface, (2) focal swelling of the cytoplasmic matrix of the ciliary shaft, and (3) occasional compound cilium. The basal bodies of the ciliated cells from which atypical cilia arose appeared normal. In mice killed 30 days after termination of NO2 exposure, the ciliary morphology returned to normal and the incidence of abnormal cilia decreased to levels observed in controls. These observations indicate that subacute exposure to NO2 causes injury to the ciliary shaft; these changes are reversible within 30 days following removal from NO2.

Animals↗

PubMed2002

Validation of the Willems badge diffusive sampler for nitrogen dioxide determinations in occupational environments.

The Willems badge, a diffusive sampler for nitrogen dioxide, has previously been validated for ambient air measurements. This paper describes the laboratory and field validation of the Willems badge for personal sampling under working environment conditions. The mean sampling rate in the laboratory tests was 46 ml min(-1), with an RSD of 12%. No statistically significant effects on sampling rate of the sampling time, concentration of NO2 or relative humidity were found. A slightly decreased sampling rate was observed at low wind velocity. This was also confirmed during static sampling, which makes the sampler less appropriate for static sampling indoors. No back diffusion was observed. Storage of the samplers for two weeks before or after exposure did not affect the sampling rate. Our analysis is based on a modified colorimetric method, performed by FIA (flow injection analysis). This technique was compared to ion chromatography analysis. The use of ion chromatography lowered the detection limit from 11 to 2 microg m(-3) for an 8 h sample, and furthermore enabled the detection of other anions. In conclusion, the diffusive sampler was found to perform well for personal measurements in industrial environments.

Air Pollutants↗

PubMed2005

Detection of nitrogen dioxide by cavity attenuated phase shift spectroscopy.

We present initial results obtained from an optical absorption sensor for the monitoring of ambient atmospheric nitrogen dioxide concentrations (0-200 ppb). This sensor utilizes cavity attenuated phase shift spectroscopy, a technology related to cavity ringdown spectroscopy. A modulated broadband incoherent light source (a 430-nm LED) is coupled to an optically resonant cavity formed by two high-reflectivity mirrors. The presence of NO(2) in the cell causes a phase shift in the signal received by a photodetector that is proportional to the NO(2) concentration. The sensor, which employed a 0.5-m cell, was shown to have a sensitivity of 0.3 ppb in the photon (shot) noise limit. Improvements in the optical coupling of the LED to the resonant cavity would allow the sensor to reach this limit with integration times of 10 s or less (corresponding to a noise equivalent absorption coefficient of <1 x 10(-8) cm(-1) Hz(-1/2)). Over a 2-day-long period of ambient atmospheric monitoring, a comparison of the sensor with an extremely accurate and precise tunable diode laser-based absorption spectrometer showed that the CAPS-based instrument was able to reliably and quantitatively measure both large and small fluctuations in the ambient nitrogen dioxide concentration.

Journal Article↗

PubMed1989

Nitrogen dioxide (NO2) inhalation, formation of microthrombi in lungs and cancer metastasis.

It is recognized that cancer cells may be introduced into circulation during surgical removal of a malignant neoplasm. The fate of these cells depends upon many factors. In this paper we present findings from an animal model which indicate that inhalation of nitrogen dioxide facilitates blood-borne cancer cell metastasis to lungs by injuring lung capillary endothelium and formation of microthrombi. Lung capillaries were evaluated by light and electron microscopy. The main lesions observed were microthrombi and injury to capillary endothelial cells, following 6 weeks of 0.35 +/- 0.05 ppm NO2 exposure. The blood-borne cancer cell metastasis was studied utilizing B16 melanoma cells in C57Bl/6J mice. A correlation was observed between increased incidence of microthrombi, endothelial cell injury and lung metastasis in exposed animals. Other adverse NO2 effects such as impairment of immune system may also participate. Inhalation of nitrogen dioxide and other air pollutants may play a significant role in enhancement of metastasis and blood vessel associated disorders.

Administration, Inhalation↗

PubMed1986

Estimation of risk of glucose 6-phosphate dehydrogenase-deficient red cells to ozone and nitrogen dioxide.

It has been suggested that the more than 1 million black Americans with the A- variant of glucose-6-phosphate dehydrogenase deficiency (G6PD) are at risk for adverse hematologic effects due to inhalation of ambient levels of oxidant gases. To evaluate this hypothesis studies were performed that included direct exposure of human G6PD-deficient red cells, and of mouse strains with different G6PD levels, to the oxidant gases ozone and nitrogen dioxide. Using the oxidant drug phenylhydrazine in part as a point of comparison, conservative extrapolation of the data indicates that exposure to levels of ozone or nitrogen dioxide at least one and probably two orders of magnitude above the LD50 would be required for any hematologic effect to be observed of pertinence to G6PD deficiency. It is concluded that there is no reason to remove or preclude from the workplace black employees with the common A- variant of red cell G6PD deficiency who potentially are exposed to oxidant gases.

Animals↗

PubMed2005

Exposure to particles and nitrogen dioxide among taxi, bus and lorry drivers.

AIM: The aims of this study have been to investigate the occurrence of systematic differences in the personal exposure to motor exhaust between different groups of taxi, bus and lorry drivers, and to study if these are influenced by the choice of exposure indicator. METHODS: We used one indicator of the gaseous phase, nitrogen dioxide (NO(2)), and one of the particle phase (measured by DataRAM), of the exhausts. A total of 121 drivers were included in the study: 39 taxi drivers, 42 bus drivers and 40 lorry drivers. Personal measurements were performed during one working day. Nitrogen dioxide was measured with passive diffusive samplers and particles with Data-RAM, a logging instrument using nephelometric monitoring. The instrument measures particles between 0.1 and 10 microm in size. RESULTS: The average exposure to NO(2) for lorry drivers was 68 microg/m(3); for bus drivers 60 microg/m(3) and for taxi drivers 48 microg/m(3). For particles the exposure was 57 microg/m(3) for lorry drivers, 44 microg/m(3) for bus drivers and 26 microg/m(3) for taxi drivers. The result remained unchanged when exposures were adjusted for variation in urban background levels of NO(2) and particulate matter with an aerodynamic diameter <10 microm (PM(10)). CONCLUSION: Lorry drivers experienced the highest exposure and taxi drivers the lowest with bus drivers in an intermediate position, regardless of whether NO(2) or particles were used as exposure indicator. The levels of both NO(2) and particles were higher for bus drivers in the city than for them driving in the suburbs. Using diesel or petrol as a fuel for taxis had no influence on the exposure for the drivers, indicating that the taxi drivers' exposure mainly depends on exhaust from surrounding traffic.

Air Pollutants, Occupational↗

PubMed2004

Effects of a novel gaseous antioxidative system containing a rosemary extract on the oxidation induced by nitrogen dioxide and ultraviolet radiation.

Rosemary is commonly used as a spice and a flavoring agent in food processing. Although the antioxidative properties of its extracts have been investigated, there have been few reports on the volatile components of rosemary. We designed a novel antioxidative system which can generate the volatile constituents in the gaseous phase from a rosemary extract and evaluated the gaseous antioxidative activities against both lipid peroxidation and cell death induced by nitrogen dioxide and ultraviolet radiation. The antioxidative effects of the major volatile components on the oxidation of linoleic acid induced by azo compounds were also investigated in a solution. The volatile components in the novel antioxidative system suppressed the Jurkat cell death induced by nitrogen dioxide and the intracellular formation of reactive oxygen species in fibroblast cells induced by ultraviolet radiation. 1,8-Cineole among the volatile components exerted an antioxidative effect against the oxidation of linoleic acid in a solution induced by azo compounds and ultraviolet radiation. These data suggest that the volatile constituents of a rosemary extract had antioxidative properties and that gaseous exposure antioxidant is a promising method for promoting health.

Antioxidants↗

PubMed1990

Short-term exposure to 0.3 ppm nitrogen dioxide does not potentiate airway responsiveness to sulfur dioxide in asthmatic subjects.

Whether short-term exposure to low levels of nitrogen dioxide (NO2) enhances airway responsiveness in asthmatic subjects is controversial. Because it is well established that asthma is associated with increased airway responsiveness to another common air pollutant, sulfur dioxide (SO2), we examined whether short-term exposure of asthmatic subjects to 0.3 ppm NO2 potentiates airway responsiveness to inhaled SO2. We exposed nine subjects with clinically stable asthma to 0.3 ppm NO2 or filtered air in an environmental room for 30 min on 2 separate days at least 1 wk apart in a double-blind, randomized fashion. A questionnaire about common symptoms related to inhaled irritants was completed before and immediately after each exposure. Each subject exercised (60 to 80 W) on a cycloergometer during the first 20 min of each exposure. We measured specific airway resistance (SRaw) and FEV1/FVC before, 5 min after, and 1 h after completion of the air or NO2 exposure. The single-breath nitrogen test (SBN2) was also performed before and 1 h after completion of the air or NO2 exposures and closing volume was determined; subsequently, SO2 dose-response curves (0.25 to 4.0 ppm) were performed via a mouthpiece. Each dose of SO2 was inhaled at a minute ventilation of 20 L/min for 4 min and was doubled until SRaw increased by at least 8 U above baseline. The dose of SO2 required to provoke an increase in SRaw of 8 U above baseline was determined by linear interpolation from the dose-response curve (PD8Uso2).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed2002

Nitrous acid, nitrogen dioxide, and ozone concentrations in residential environments.

Nitrous acid (HONO) may be generated by heterogeneous reactions of nitrogen dioxide and direct emission from combustion sources. Interactions among nitrogen oxides and ozone are important for outdoor photochemical reactions. However, little is known of indoor HONO levels or the relationship between residential HONO, NO(2), and O(3) concentrations in occupied houses. Six-day integrated indoor and outdoor concentrations of the three pollutants were simultaneously measured in two communities in Southern California using passive samplers. The average indoor HONO concentration was 4.6 ppb, compared to 0.9 ppb for outdoor HONO. Average indoor and outdoor NO(2)concentrations were 28 and 20.1 ppb, respectively. Indoor O(3) concentrations were low (average 14.9 ppb) in comparison to the outdoor levels (average 56.5 ppb). Housing characteristics, including community and presence of a gas range, were significantly associated with indoor NO(2) and HONO concentrations. Indoor HONO levels were closely correlated with indoor NO(2) levels and were about 17% of indoor NO(2) concentrations. Indoor HONO levels were inversely correlated with indoor O(3) levels. The measurements demonstrated the occurrence of substantial residential indoor HONO concentrations and associations among the three indoor air pollutants.

Air Pollution, Indoor↗

PubMed2001

Nitrogen dioxide induces death in lung epithelial cells in a density-dependent manner.

Nitrogen dioxide (*NO2) is commonly known as an indoor and outdoor air pollutant. Inhalation of *NO2 is associated with epithelial cell injury, inflammation, and the aggravation of asthma. *NO2 can also be formed during inflammation, by the metabolism of nitric oxide. We describe a gas-phase exposure system for in vitro exposure of lung epithelial cells to *NO2. Immunofluorescence revealed 3-nitrotyrosine immunoreactivity of rat alveolar type II epithelial cells exposed to 5 parts per million of *NO2 for 4 h. Comparative analysis of log-phase and confluent cultures demonstrated that cell death occurred extensively in log-phase cells, whereas minimal death was observed in confluent cultures. Peroxynitrite (ONOO-) or the ONOO- generator 3-morpholinosydnonimine (SIN-1) caused similar amounts of death. Further, exposure of wounded cell cultures to *NO(2) or SIN-1 revealed that death was restricted to cells repopulating a wounded area. Cycloheximide or actinomycin D, inhibitors or protein and messenger RNA synthesis, respectively, significantly reduced terminal transferase reactivity, suggesting that a new protein(s) may be required for cell death. These results suggest that during restitution after pulmonary injury, epithelium may be sensitive to cell death by reactive nitrogen species.

Cell Count↗

PubMed1987

Ion chromatographic determination of nitrogen dioxide and sulphur dioxide in the atmosphere using tri-ethanolamine-potassium hydroxide-coated cartridges.

Nitrogen dioxide (NO2) and sulphur dioxide (SO2) in air were sampled by the use of a Sep-Pak C18 cartridge impregnated with triethanolamine-potassium hydroxide. The trapped NO2 and SO2 were eluted with a 8 mM sodium carbonate-3 mM sodium hydrogencarbonate solution and simultaneously determined by ion chromatography. In the active sampling mode, NO2 was determined with 5.2% relative standard deviation at 95 ppb and SO2 was determined with 2.4-5.3% relative standard deviation at 54-184 ppb. The recoveries were 85-98% for NO2 and 91-105% for SO2. In the passive sampling mode, the average concentrations of NO2 and SO2 were determined with 2.4-6.8 and 2.8-7.9% relative standard deviation, respectively, at atmospheric levels for 6-24 days.

Air Pollutants, Occupational↗

PubMed1994

An automated system for animal exposure to nitrogen dioxide.

We have designed an automated system for controlled exposure of rodents to nitrogen dioxide (NO2). The system consists of 1) two stainless-steel exposure chambers (3.96 m3), for control and treated animals, in which temperature, humidity, and air changes are consistent with current guidelines for rodent housing; 2) a cylinder containing 1% NO2 in N2; 3) a detector connected with a personal computer system that monitors the NO2 concentration, and regulates the NO2 influx, using a closed-loop feedback; and 4) a fan system to distribute the gas uniformly within the chambers. In a typical experiment rats were exposed to 15 ppm of NO2, and changes in the differential count of polymorphonuclear leukocytes, macrophages, and lymphocytes in bronchoalveolar lavage fluid were investigated.

Animals↗