AIM AND METHODSNew method to analyse nitrate and nitrite concentrations in saliva, serum and urine was developed using high performance liquid chromatography.

RESULTSThe whole isolation process was completed in less than 7 minutes, the determination linearity of nitrate and nitrite were 0.7 ng-100 ng and 5 ng-100 ng, respectively. MINIMUM: Detectable limits of nitrate and nitrite were 0.3 ng and 2 ng, respectively. Nitrate recovery ratio was 99%-102% and nitrite recovery ratio was 99%-104%. The RSD of nitrate and nitrite was 0.8% and 1.7%, respectively.

CONCLUSIONIn comparison with other methods available, the present method seems to be simpler, more sensitive and specific.

Body Fluids ; chemistry ; Chromatography, High Pressure Liquid ; methods ; Nitrates ; analysis ; Nitrites ; analysis

The performance of internal-loop air-lift nitrifying bioreactor was good with strong tolerance to influent ammonia concentration (78.49 mmol/L), high volume converting rate (163.18 mmol/L.d) and obvious working stability (ammonia removal > 94.42%). During operation of internal-loop air-lift bioreactor, the nitrifying activated sludge was granulated. The nitrifying granular activated sludge began to appear on day 45. Its average diameter was 0.83 mm, settling velocity was 55.53 m/h and specific ammonia removal rate was 0.95 mmol (NH4(+)-N)/g (VS).d. The nitrifying granular activated sludge had the activity for anaerobic ammonia oxidation with ammonia oxidation rate of 0.23 mmol (NH4(+)-N)/g(VS).d and nitrite reduction rate of 0.24 mmol (NO2(-)-N)/g(VS).d.
Ammonia ; metabolism ; Anaerobiosis ; Bioreactors ; Nitrites ; metabolism ; Nitrogen ; metabolism ; Oxidation-Reduction ; Sewage ; analysis

OBJECTIVETo determine the cause of acute poisoning occurred in a factory in Yangjiang city, Guangdong province.

METHODSIn a cross-sectional study, interviews were conducted with the administrators of the factory and the local physician. A review was conducted on the water system used for industrial purposes and a separate system used by workers for drinking water. Treatment and discharge of industrial waste water were examined. Face-to-face interview was conducted to identify risk of exposure for illness among workers.

RESULTSA total number of 36 cases were identified in the plant and the attack rate was 16.4% (36/220). The incubation period (time between drinking polluted water and the onset of symptoms) had a median of 90 minutes (range: 30 - 230 minutes). Consuming water at the factory increased the attack rate and a dose-response effect was identified (chi(2)(trend) = 79.115, P < 0.01). The nitrite content of residuals in drinking water exceeded the WHO standard (1 ppm).

CONCLUSIONSThe accident of acute poisoning was due to drinking water contaminated with sodium nitrite. The prevention of drinking water contaminated by toxic chemicals like sodium nitrite, and the design of industrial and potable water supply system need to be carefully reviewed. Regulations should be developed and enforced to minimize the impact of industrial waste water discharges to guarantee the access to clean drinking water.

Acute Disease ; Adolescent ; Adult ; Female ; Humans ; Industrial Waste ; Male ; Middle Aged ; Nitrites ; poisoning ; Water Pollutants, Chemical ; poisoning ; Water Supply ; analysis

OBJECTIVETo determine the expressions of endothelial nitric oxide synthase traffic inducer (NOSTRIN) and endothelial nitric oxide synthase (eNOS) in the testis tissue of azoospermia patients, and investigate their correlation with the pathogenesis of azoospermia.

METHODSWe detected the expressions of NOSTRIN and NOSTRIN mRNA by immunohistochemistry and RT-PCR respectively, determined the activity of eNOS by spectrophotometry, and measured the stable metabolic end product NO, NO2- / NO3-, by nitrate reductase assay in the testis tissues of 17 patients with idiopathic azoospermia (the azoospermia group) and 10 normal men (the normal group).

RESULTSNOSTRIN and NOSTRIN mRNA were expressed in the spermatogonia, sertoli cells, stromal cells and vascular endothelial cells, more lowly in the azoospermia than in the normal group (0.312 +/- 0.076 versus 0.793 +/- 0.082, P < 0.01). The activity of eNOS was significantly increased in the idiopathic azoospermia patients ([33.727 +/- 3.58] U/mg) compared with the normal men ([17.69 +/- 3.84] U/mg) (P < 0.01). The level of NO2- / NO3- was significantly higher in the azoospermia than in the normal group ([48.56 +/- 8.49] micromol/L versus [25.37 +/- 9.61] micromol/L, P < 0.01). The expression of NOSTRIN showed a significant negative correlation with the activity of eNOS (r = -0.57, P < 0.01) as well as with the level of NO2- / NO3- (r = -0.61, P < 0.01) in the testis tissue of the idiopathic azoospermia patients.

CONCLUSIONThe expression of NOSTRIN is decreased, while the activity of eNOS and the level of NO2- / NO3- increased in the testis tissue of azoospermia patients, which may be associated with the pathogenesis of azoospermia.

Adult ; Azoospermia ; metabolism ; Humans ; Intracellular Signaling Peptides and Proteins ; metabolism ; Male ; Nitrates ; analysis ; Nitric Oxide Synthase Type III ; metabolism ; Nitrites ; analysis ; Spermatogenesis ; Testis ; metabolism

Start-up and process control of a pilot-scale anaerobic ammonium-oxidizing (Anammox) bioreactor were studied at ambient temperature. Inoculated with a mixture of nitrification-denitrification sludge, nitritation sludge, anaerobic floc sludge and anaerobic granular sludge, the pilot-scale Anammox bioreactor was successfully started up within 255 days at 5 degrees C-27 degrees C. The nitrogen removal rate reached 1.30 kg/(m3 x d). Three facets were taken into account to facilitate the process initiation. First, in terms of alkalization in Anammox, influent pH was kept at about 6.8. Besides, nitrite concentration was kept as low as 13-36 mg/L. Finally, 2% (volumetric ratio) of Anammox sludge from lab-scale bioreactors was supplemented to the pilot-scale one.
Ammonia ; chemistry ; metabolism ; Bacteria, Anaerobic ; metabolism ; Bioreactors ; microbiology ; Nitrites ; analysis ; Nitrogen ; metabolism ; Oxidation-Reduction ; Sewage ; microbiology ; Waste Disposal, Fluid ; instrumentation ; methods

OBJECTIVETo explore the relationship between nitrite levels in the exhaled breath condensates (EBC) and the severity of asthma.

METHODSSixty asthmatic patients with exacerbation (including 23 with mild, 21 with moderate, and 16 with severe asthma) and 23 healthy nonsmokers were enrolled in this study. The lung function tests were performed and nitrite levels measured in the EBC by the spectrophotometry and nitric oxide assay kit in these subjects. The percentage of eosinophils was also measured in induced sputum by Wright staining.

RESULTSThe concentrations of nitrites in the EBC and the percentage of eosinophils in induced sputum in the asthmatic patients were significantly higher than those of the healthy subjects (P<0.01), and showed positive correlations to the disease severity. A significant positive correlation was found between nitrites in the EBC and percentage of eosinophils in induced sputum (r=0.706, P<0.01). The concentration of exhaled nitrites was inversely correlated to MEF50% (r=-0.806, P<0.01) and FEV1% (r=-0.724, P<0.01).

CONCLUSIONNitrite level in the EBC may serve as useful indicators for estimating the severity of asthma.

Adult ; Asthma ; metabolism ; Breath Tests ; methods ; Case-Control Studies ; Exhalation ; Female ; Forced Expiratory Volume ; Humans ; Male ; Middle Aged ; Nitrites ; analysis ; Respiratory Function Tests ; Severity of Illness Index ; Young Adult

BACKGROUNDMaternal exposure to nitrate, nitrite, and N-nitroso compounds from drinking water or diet has been associated with an increased risk of neural tube defects (NTDs) in some studies. Pickled vegetables contain relatively large amounts of nitrite and N-nitroso compounds. We examined the association between maternal periconceptional consumption of pickled vegetables and NTDs in Shanxi Province of northern China.

METHODSData were derived from a population based case-control study of major external birth defects in four counties of Shanxi Province. Participants included 519 NTDs cases identified between 2003 and 2007 and 694 healthy controls. Exposure information was collected within 1 week after delivery. Multivariable non-conditional Logistic regression model was used to estimate the adjusted odds ratio (OR) controlling for potential confounding variables.

RESULTSThe risk of NTDs was positively associated with the frequency of the consumption of pickled vegetables by the mother. Compared with pickled vegetables consumption at < 1 meal/week, the adjusted OR for consumption at 1 - 3, 4 - 6, and > 6 meals/week were 1.3 (95% confidence interval (CI): 1.0, 1.8), 1.9 (1.1, 3.2), and 3.6 (1.9, 6.9), respectively. A protective effect was found for maternal meat consumption at ≥ 1 meal/week (adjusted OR: 0.6, 95%CI: 0.4, 0.7) and egg or milk consumption at ≥ 1 meal/week (adjusted OR: 0.6, 95%CI: 0.4, 0.8).

CONCLUSIONMaternal periconceptional consumption of pickled vegetables may increase the risk for NTDs in Shanxi Province.

Adult ; Case-Control Studies ; Female ; Humans ; Infant, Newborn ; Logistic Models ; Maternal Exposure ; adverse effects ; Multivariate Analysis ; Neural Tube Defects ; etiology ; Nitrites ; adverse effects ; Nitroso Compounds ; adverse effects ; Pregnancy ; Risk Factors ; Vegetables ; adverse effects ; chemistry ; Young Adult

Tumor target-derived soluble secretary factor has been known to influence macrophage activation to induce nitric oxide (NO) production. Since heme oxigenase-1 (HO-1) is induced by a variety of conditions associated with oxidative stress, we questioned whether soluble factor from tumor cells induces HO-1 through NO-dependent mechanism in macrophages. We designated this factor as a tumor-derived macrophage-activating factor (TMAF), because of its ability to activate macrophages to induce iNOS. Although TMAF alone showed modest activity, TMAF in combination with IFN-gamma significantly induced iNOS expression and NO synthesis. Simultaneously, TMAF induced HO-1 and this induction was slightly augmented by IFN-gamma. Surprisingly, however, induction of HO-1 by TMAF was not inhibited by the treatment with the highly selective iNOS inhibitor, 1400 W, indicating that TMAF induces the HO-1 enzyme by a NO-independent mechanism. While rIFN-gamma alone induced iNOS, it had no effect on HO-1 induction by itself. Collectively, the current study reveals that soluble factor from tumor target cells induces HO-1 enzyme in macrophages. However, overall biological significance of this phenomenon remains to be determined.
Animals ; Antineoplastic Agents/pharmacology ; Bladder Neoplasms/metabolism/pathology ; Cell Line ; Drug Interactions ; Gene Expression Regulation, Enzymologic/drug effects ; Heme Oxygenase (Decyclizing)/analysis/*genetics ; Human ; Interferon Type II/pharmacology ; Macrophage Activation/drug effects ; Macrophages, Peritoneal/*metabolism ; Mice ; Mice, Inbred C57BL ; Nitric Oxide/biosynthesis/*metabolism ; Nitric-Oxide Synthase/genetics/metabolism ; Nitrites/analysis ; Tumor Cells, Cultured

Pathophysiological implications of the vascular nitric oxide (NO)/cGMP pathway were investigated in various rat models of hypertension. The expression of brain and endothelial constitutive NO synthases (bNOS, ecNOS) was determined by Western blot analysis, and the biochemical activity of soluble and particulate guanylate cyclases (GC) was assessed by the amount of cGMP generated in the thoracic aortae of rats with deoxycorticosterone acetate (DOCA)-salt, two-kidney, one dip (2K1C), and spontaneous hypertension (SHR). Plasma nitrite/ nitrate levels were decreased in DOCA-salt and 2K1C hypertension, and increased in SHR. The vascular expression of bNOS as well as that of ecNOS was decreased along with tissue nitrite/nitrate contents in DOCA-salt and 2K1C hypertension. The expression of both bNOS and ecNOS was increased in SHR with concomitant changes of tissue nitrite/nitrate contents. The activity of soluble GC was decreased, and that of particulate GC was increased in DOCA-salt hypertension. The soluble GC activity was increased, while the particulate GC activity was not affected in 2K1C hypertension. The soluble GC activity was not significantly changed, but the particulate GC activity was decreased in SHR. These results indicate that the high blood pressure is associated with differentially-altered vascular NO/cGMP pathway in different models of hypertension.
Animal ; Aorta, Thoracic/enzymology ; Atrial Natriuretic Factor/blood ; Blotting, Western ; Desoxycorticosterone ; Guanylate Cyclase/metabolism ; Guanylate Cyclase/analysis* ; Hypertension/enzymology* ; Hypertension/chemically induced ; Isoenzymes/metabolism ; Isoenzymes/analysis* ; Male ; Nitrates/blood ; Nitric-Oxide Synthase/metabolism ; Nitrites/blood ; Rats ; Rats, Inbred SHR ; Rats, Inbred WKY ; Rats, Sprague-Dawley ; Solubility

BACKGROUNDSalivary nitrate is positively correlated with plasma nitrate and its level is 9 times the plasma level after nitrate loading. Nitrate in saliva is known to be reduced to nitrite by oral bacteria. Nitrate and nitrite levels in saliva are 3 - 5 times those in serum in physiological conditions respectively in our previous study. The biological functions of high salivary nitrate and nitrite are still not well understood. The aim of this in vitro study was to investigate the antimicrobial effects of nitrate and nitrite on main oral pathogens under acidic conditions.

METHODSSix common oral pathogens including Streptococcus mutans NCTC 10449, Lactobacillus acidophilus ATCC 4646, Porphyromonas gingivalis ATCC 33277, Capnocytophaga gingivalis ATCC 33624, Fusobacterium nucleatum ATCC 10953, and Candida albicans ATCC 10231 were cultured in liquid medium. Sodium nitrate or sodium nitrite was added to the medium to final concentrations of 0, 0.5, 1, 2, and 10 mmol/L. All of the microorganisms were incubated for 24 to 48 hours. The optical densities (OD) of cell suspensions were determined and the cultures were transferred to solid nutrient broth medium to observe the minimum inhibitory concentration and minimum bactericidal/fungicidal concentration for the six tested pathogens.

RESULTSNitrite at concentrations of 0.5 to 10 mmol/L had an inhibitory effect on all tested organisms at low pH values. The antimicrobial effect of nitrite increased with the acidity of the medium. Streptococcus mutans NCTC 10449 was highly sensitive to nitrite at low pH values. Lactobacillus acidophilus ATCC 4646 and Candida albicans ATCC 10231 were relatively resistant to acidified nitrite. Nitrate at the given concentrations and under acidic conditions had no inhibitory effect on the growth of any of the tested pathogens.

CONCLUSIONNitrite, at a concentration equal to that in human saliva, is both cytocidal and cytostatic to six principal oral pathogens in vitro, whereas nitrate at a similar concentration has no antimicrobial effect on these organisms.

Anti-Infective Agents ; pharmacology ; Candida albicans ; drug effects ; Fusobacterium nucleatum ; drug effects ; Hydrogen-Ion Concentration ; Lactobacillus acidophilus ; drug effects ; Microbial Sensitivity Tests ; Mouth ; microbiology ; Nitrates ; analysis ; blood ; pharmacology ; Nitrites ; analysis ; blood ; pharmacology ; Porphyromonas gingivalis ; drug effects ; Saliva ; chemistry ; Streptococcus mutans ; drug effects