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At least 19 recordsLinked to original sources
PubMedDate not supplied

[Disorders of various links in heme synthesis in subjects with occupational exposure to nitrogen oxides].

In 35 male subjects with long-standing exposure to low concentrations of nitrogen oxides the morphotic elements of peripheral blood, the activity of delta-aminolaevulinic acid dehydratase(ALA-D) in erythrocytes and urinary elimination of delta-aminolaevulinic acid (ALA), coproporphyrin (CP) and porphobilinogen (PBG) were determined. The control group comprised 29 healthy men not exposed to toxic substances. Statistically significant methaemoglobinaemia, decreased heamoglobin concentration and reduced mean heamoglobin weight in erythrocytes were found in the exposed subjects. At the same time the activity of ALA-D in erythrocytes was increased and urinary elimination of coproporphyrin was increased while that of ALA was decreased. Decreased haemoglobin concentration in peripheral blood in cases of chronic exposure to nitrogen oxides may depend on their effect on the enzymes participating in haeme synthesis. However, increased ALA-D activity in erythrocytes found in these cases may be of some importance in evaluation of exposure to nitrogen oxides.

Adult↗
PubMed1976

Inhibition of methanogenesis in salt marsh sediments and whole-cell suspensions of methanogenic bacteria by nitrogen oxides.

Hydrogen-dependent evolution of methane from salt marsh sediments and whole-cell suspensions of Methanobacterium thermoautotrophicum and Methanobacterium fornicicum ceased or decreased after the introduction of nitrate, nitrite, nitric oxide, or nitrous oxide. Sulfite had a similar effect on methanogenesis in the whole-cell suspensions. In salt marsh sediments, nitrous oxide was the strongest inhibitor, followed by nitric oxide, nitrite, and nitrate in decreasing order of inhibition. In whole-cell suspensions, nitric oxide was the strongest inhibitor, followed by nitrous oxide, nitrite, and nitrate. Consideration of the results from experiments using an indicator of oxidation potential, along with the reversed order of effectiveness of the nitrogen oxides in relation to their degree of reduction ,suggests that the inhibitory effect observed was not due to a redox change. Evidence is also presented that suggests that the decrease in the rate of methane production in the presence of oxides of nitrogen was not attributable to competition for methane-producing substrates.

Bacteria↗
PubMed1979

Studies on the biological effects of nitrogen oxides and photochemical oxidants.

The animal studies in mice resulted as follows. Long-term exposure to NO2 at or above 0.5 ppm affected primarily the respiratory organs. The pulmonary effect of NO was slighter than NO2. Nitrosylhemoglobin formation in vivo was much smaller than in vitro strong affinity of NO with hemoglobin. The components other than O3 contained in the photochemically formed oxidant mixtures enhanced the effect of O3 alone. Symptoms of the patients seriously injured by photochemical smog in Japan suggested the different type in quality from the Los Angeles-type smog.

Air Pollution↗
PubMed1978

Rapid formation of N-nitrosamines from nitrogen oxides under neutral and alkaline conditions.

The formation of carcinogenic N-nitrosamines in neutral and alkaline aqueous solutions (pH 6-14) at 25 degrees C is reported using dissolved N2O3 and N2O4 gases. These reactions are very much faster than those with acidified nitrite: typically, 2 X 10(-3) M amine gives ca. 10-50% N-nitrosamine in a few seconds with 5-20 fold excess of nitrogen oxide. The N-nitrosamine yield in 0.1 M sodium hydroxide is independent of amine basicity from pKA 11.2-0.99, but decreases with decreasing pH of the reaction solution for the more basic amines. Significantly, N-nitrosamine yields are not lowered with diluted nitrogen oxides (1000 ppm) and moderately basic amines (eg. N-methylpiperazine) react readily at physiological pH. The mechanism by which these reactions occur is discussed, with particular reference to the existence of two reactive tautomeric forms of N2O3 and N2O4. The formation of carcinogenic N-nitrosamines from NO in ethanol at 25 degrees C is also reported. These reactions are slow in the absence of air (oxygen), I2 or metal salts. Oxygen accelerates nitrosation by converting NO via NO2 to either N2O3 or N2O4, but both I2 and metal salts are effective under anaerobic conditions, where reaction rates are virtually independent of amine basicity but depend on the nature of the added reagent. The most effective substance is I2, which gives quantitative yields of N-nitrosamine in a few minutes at 25 degrees C by forming the reactive nitrosyl iodide (NOI) reagent. Acceleration in ethanol at 25 degrees C is also observed with AgI, CuI, CuII, ZnII, FeIII and CoII salts, among others, with substantial amounts of N-nitrosamine being produced in ca. 30-300 min. Metal iodides intervene by way of the NOI reagent, as for I2, but other salts require a mechanism involving reaction between a metal-amine complex and NO, itself. The results show that carcinogenic N-nitrosamines may form under a much wider range of experimental conditions than suspected hitherto. Their relevance to human exposure is discussed, with particular reference to urban pollution and the effect of dietary antioxidants.

Amines↗
PubMed1977

[Quantitative determination of nitrogen oxide in cigarette smoke by means of chemiluminescence (author's transl)].

A measuring method with a chemiluminescence-analyzer is developed for determining the content of nitrogen oxide in cigarette smoke. This method is suitable for puff/puff analysis. It could be demonstrated that a determination of fresh smoke is necessary as nitrogen oxides react very quickly with other constituents of the vapor phase. Measured values have to be corrected for a quench factor in analogy to the CO2 concentration, as carbon dioxide shows an influence on the measuring sensitivity of the chemiluminescence-analyzer.

Luminescent Measurements↗
PubMedDate not supplied

Changes of beta-glucuronidase activity in peripheral blood lymphocytes in rats exposed to a mixture of nitrogen oxides and chlorine.

The activity of beta-glucuronidase (BG) was tested cytochemically in the lymphocytes of peripheral blood of rats exposed to a mixture of nitrogen oxides (1.22 mg/m3) and chlorine (1.02 mg/m3) for 12 weeks. The number of lymphocytes was reduced, the activity of BG was depressed and the enzyme was shifted from the lysosomes to the cytoplasm of these cells. A relation between the changes in the lymphocytes at the subcellular level and the immunological responses of the organism are discussed.

Animals↗
PubMed1979

Activity of N-acetyl-beta-glucosaminidase in lymphocytes of rats exposed to mixture of nitrogen oxides and chlorine.

Activity of N-acetyl-beta-glucosaminidase (GS) has been cytochemically studied in peripheral blood lymphocytes of rats exposed to the mixture of nitrogen oxides (1.22 mg/m3) and chlorine (1.02 mg/m3) during a period of 12 weeks. The decrease of the total lymphocyte count and in increase of the count of GS-positive lymphocytes with cytoplasmatic but not exclusively lysosomal localization have been noted after exposure. The increase of the count of lymphocytes containing the enzyme within both lysosomal granules and cytoplasm has been correlated with the exposure time and accompanied by diminishing the count of lymphocytes containing the enzyme within the lysosomal granules exclusively. The authors believe the changes noted above may result from toxic damage of lysosomes or the immune response of lymphocytes against antigens released from the damaged tissues.

Acetylglucosaminidase↗
PubMed1978

[Electron paramagnetic resonance study of the products of the reaction between nitrogen oxides and several organic compounds].

A method of electron paramagnetic resonance was applied to the study of a possibility of paramagnetic centres formation in the nitrogen oxide reaction with saturated and unsaturated fatty acids and aromatic amino acids. Several paramagnetic centres are formed in interaction of NO2 with oleic acid at 20 degrees C. Saturated fatty acids formed no paramagnetic centres in the reaction with NO2. NO formed no paramagnetic centres not only with butyric, palmitic, and stearic acids, but also with oleic acid. The capacity of NO2 to form paramagentic centres with tyrosine in its saturated solution was revealed. In case of interaction between NO and NO2 with saturated phenylalanine and tryptophane solutions no formation of paramagnetic centres was observed. It is suggested that unsaturated fatty acids and tyrosine remnants of the membrane lipoprotein complexes could serve as peculiar targets with which NO2 interacted, and that formation of paramagnetic centres in the NO2 reaction with the mentioned substances was the primary act of the membrane damage.

Amino Acids↗
PubMed1979

Influence of nitrous oxide, nitrogen, neon, and helium on the beating frequency of the mouse sinus node at high pressure.

The beating frequency (BF) reducing effect of 150 atm of hydrostatic pressure on mammalian cardiac pacemaker tissue (hyperbaric bradycardia) was counteracted by dissolved gas only if the gas was added after hydrostatic compression. The effect on BF seemed to be related to the narcotic potency of the gas and the effect was reversible. The gases tested were N2O, N2, Ne, and He, in decreasing order of potency. If N2O was added at a moderately raised ambient pressure prior to hydrostatic compression to 150 atm, there was no difference in the degree of hyperbaric bradycardia, compared to compression without gas. During decompression, however, experiments performed with gas showed a significantly higher gain in BF compared to experiments without gas. Autonomic blockade seemed to eliminate the difference between decompression with and without N2O. The results demonstrate that N2O, N2, and Ne, and to a small extent He, may counteract the retarding effect that increased hydrostatic pressure has on cardiac pacemaker activity. These effects on the cardiac pacemaker are similar both to the effects of increased hydrostatic pressure and of gases at elevated pressures on the central nervous system, but some important differences remain to be explained.

Animals↗