RESEARCH ON THE NITRATES AND NITRITES CONTENT IN SOME VEGETABLE SPECIES, CLUJ COUNTY, ROMANIA AND ANTWERPEN, BELGIUM

BACKGROUND: Nitric oxide is a multifunctional signaling molecule that regulates processes such as vasodilation, platelet aggregation, immunotoxicity, and carcinogenesis. Currently, nitric oxide is believed to be involved in the development and progression of tumor lesions. Depending on the concentration, nitric oxide can affect tumor cell apoptosis, metastasis, and angiogenesis intensity. It also demonstrates anti-tumor and cytotoxic properties. Additionally, being the end products of nitric oxide, the total concentration of nitrites and nitrates can be considered diagnostic and prognostic markers for subclinical forms and recurrent cancer. AIM: This study aimed to compare total nitrite and nitrate concentrations in the saliva of healthy volunteers and patients with tumors localized at different sites, depending on sex and age. METHODS: The study included 106 patients, with 74 in the comparison group (healthy volunteers) and 32 in the cancer group. The study participants provided fasting saliva samples (5.0 ± 0.5 mL) in the morning. The samples were collected in plastic test tubes. The total concentration of nitrites and nitrates was determined by spectrophotometry using the colorimetric nitrite diazotization reaction with sulfanilamide and 1-naphthylamine. Nitrates were reduced to nitrites using zinc powder in an alkaline medium containing a copper sulfate-ammonia complex. Next, nitrite ions were quantified. RESULTS: The total concentration of nitrites and nitrates in the saliva samples of healthy volunteers was 129 [59; 261] μM, with nitrites at 109 [36.4; 254.0] μM and nitrates at 6.4 [2.1; 20.9] μM. Nitrate and nitrite concentrations in saliva did not differ statistically between men and women. Nitrate and nitrite concentrations also increased with age. The total concentration of nitrites and nitrates in the saliva samples of patients with tumors at different sites was 14.5 [6.5; 80.1] μM, with nitrites at 9.2 [3.0; 79.4] μM and nitrates at 3.9 [1.5; 7.7] μM. The concentrations were statistically significantly lower compared with those in healthy volunteers. Additionally, patients with cancer aged 40 to 69 years demonstrated the most significant decrease in the total concentration of nitrites and nitrates. CONCLUSION: The results suggest significant differences in nitrite and nitrate concentrations in saliva between healthy volunteers and patients with cancer. Further research could lead to new approaches for diagnosing cancer by using nitrite and nitrate concentrations in saliva as signal markers.

Background:Nitrite (NO2−) and nitrate (NO3−) contaminations of groundwater are considered as one of the major health challenges in recent decades. This study aimed to evaluate the nitrite and nitrate concentrations in the drinking groundwater of Shiraz, South-central Iran by statistical models.Methods:From 43 active wells of Shiraz drinking water supplies, 344 samples were collected in the high and low precipitation seasons from 2010 to 2014. Nitrate and nitrite concentrations were tested by a DR6000 spectrophotometer, and the results were analyzed by different software, including SPSS ver. 20, ArcView GIS 9.3. It was done by variable and multivariate regression models. In all tests, the level of significance was set at 5%.Results:Nitrate concentrations in the samples were in the range of 5 to 72 mg/l, and 38 (11%) of the samples had nitrate concentrations above the standard level 10 mg/L as nitrogen. The annual mean concentration of nitrite varied from 0 to 0.025 mg/l. There was an inverse correlation between nitrate and nitrite concentrations and well depths.Conclusion:The most important reason for the high concentration of nitrate in Shiraz drinking groundwater supplies were lack of health privacy of wells, the impact of residential construction around drinking water wells, and placement of wells in the direction of groundwater flow.

BackgroundDietary nitrate consumption can increase concentrations of nitrate and nitrite in blood, saliva, and urine. Whether the change in concentrations is influenced by age is currently unknown. ObjectivesWe aimed to measure changes in nitrate and nitrite concentrations in plasma, urine, and saliva and exhaled NO concentrations after single incremental doses of dietary nitrate in young and older healthy adults. MethodsTwelve young (18–35 y old) and 12 older (60–75 y old) healthy, nonsmoking participants consumed single doses of 100 g, 200 g, 300 g whole beetroot (BR) and 1000 mg potassium nitrate (positive control) ≥7 d apart in a crossover, randomized clinical trial. Plasma nitrate and nitrite concentrations and exhaled NO concentrations were measured over a 5-h period. Salivary nitrate and nitrite concentrations were measured over a 12-h period and urinary nitrate over a 24-h period. Time, intervention, age, and interaction effects were measured with repeated-measures ANOVAs. ResultsDose-dependent increases were seen in plasma, salivary, and urinary nitrate after BR ingestion (all P ≤ 0.002) but there were no differences between age groups at baseline (all P ≥ 0.56) or postintervention (all P ≥ 0.12). Plasma nitrite concentrations were higher in young than older participants at baseline (P = 0.04) and after consumption of 200 g (P = 0.04; +25.7 nmol/L; 95% CI: 0.97, 50.3 nmol/L) and 300 g BR (P = 0.02; +50.3 nmol/L; 95% CI: 8.57, 92.1 nmol/L). Baseline fractional exhaled NO (FeNO) concentrations were higher in the younger group [P = 0.03; +8.60 parts per billion (ppb); 95% CI: 0.80, 16.3 ppb], and rose significantly over the 5-h period, peaking 5 h after KNO3 consumption (39.4 ± 4.5 ppb; P < 0.001); however, changes in FeNO were not influenced by age (P = 0.276). ConclusionsBR is a source of bioavailable dietary nitrate in both young and older adults and can effectively raise nitrite and nitrate concentrations. Lower plasma nitrite and FeNO concentrations were found in older subjects, confirming the impact of ageing on NO bioavailability across different systems.This trial was registered at www.isrctn.com as ISRCTN86706442.

Nitric oxide (NO) is an endogenous mediator of many physiological processes, many of which are mediated by cyclic guanosine 3',5'-monophosphate (cGMP). Much effort has been made to validate clinical markers of NO production or bioavailability. While the measurement of plasma nitrate, nitrite, and cGMP concentrations have been suggested to reflect endogenous production of NO, there is no study showing whether there is correlation between these three markers. In the present study, we investigate whether there is correlation between the plasma concentrations of nitrate, nitrite, and cGMP in a relatively homogeneous group of 141 healthy subjects. Venous blood samples were collected from healthy male subjects and plasma aliquots were then immediately removed and stored at -70 degrees C until analysed in duplicate for their nitrite and nitrate content using ozone-based chemiluminescence assays. Plasma cGMP levels were determined by using a commercial enzyme immunoassay. While we found no significant correlation between plasma nitrite and nitrate concentrations (P = 0.747), or between plasma nitrate and cGMP concentrations (P = 0.221), a significant positive correlation was found between plasma cGMP and nitrite concentrations (P = 0.017, r(s) = 0.270). The significant correlation we found between plasma nitrite and cGMP concentrations is consistent with the notion that nitrite or cGMP concentrations in plasma may be useful clinical markers of NO formation in healthy subjects.

To measure cerebrospinal fluid and plasma nitrite and nitrate concentrations as indicators of nitric oxide production in adults after severe closed-head injury. To determine if there is an association between cerebrospinal fluid and plasma nitrite and nitrate concentrations, and cerebral blood flow, arterio-jugular oxygen content difference, injury severity, and outcome after severe closed-head injury. A prospective, clinical study. Multidisciplinary intensive care unit. Fifteen comatose (Glasgow Coma Scale score of < or = 7) adult patients with severe closed-head injury were studied during the prospective, randomized evaluation of the effect of moderate hypothermia (32 degrees C for 24 hrs) on neurologic outcome after closed-head injury. Seven patients were in the hypothermic group and eight patients were in the normothermic treatment group. None. Patients were examined sequentially, every 12 hrs for 2 days. Intraventricular cerebrospinal fluid was assayed for nitrite and nitrate concentrations. Cerebral blood flow was measured by the 133xenon intravenous method. Simultaneous blood samples were obtained for measurements of arterio-jugular oxygen content difference and plasma nitrite and nitrate concentrations. Cerebral metabolic rate for oxygen was calculated. Cerebrospinal fluid nitrite and nitrate concentrations were highest at 30 to 42 hrs vs. 6 to 18, 18 to 30, and 42 to 54 hrs (26.4 +/- 3.3 vs. 17.3 +/- 2.1, 20.0 +/- 2.2, and 18.8 +/- 2.4 microM, respectively, p < .05). There was no difference over time in plasma nitrite and nitrate concentrations. Cerebral blood flow was increased and arterio-jugular oxygen content difference was reduced at 18 to 30, 30 to 42, and 42 to 54 hrs vs. 6 to 18 hrs (p < .05). At 30 to 42 hrs, cerebrospinal fluid nitrite and nitrate concentrations were 80% higher in patients who died vs. survivors (36.4 +/- 3.2 vs. 20.2 +/- 3.6, p < .05). Using a generalized, multivariate, linear regression model, both plasma nitrite and nitrate concentrations and injury Severity Score independently predicted cerebrospinal fluid nitrite and nitrate concentrations (p < .00001 and p = .0053, respectively). Cerebral blood flow and arterio-jugular oxygen content difference were not associated with cerebrospinal fluid or plasma nitrite and nitrate concentrations using this model. Cerebrospinal fluid nitrite and nitrate concentrations were increased over time in hypothermic vs. normothermic patients. But, where this difference occurred could not be determined by multiple comparisons (p = .03). The hypothermic patients had lower admission Glasgow Coma Scale scores than normothermic patients (p = .04) and tended to have higher injury Severity Scores (p = .09). Increases in cerebrospinal fluid nitrite and nitrate concentrations peaked at 30 to 42 hrs after severe closed-head injury. This increase in cerebrospinal fluid nitrite and nitrate concentrations was greater in nonsurvivors. Also, cerebrospinal fluid and plasma nitrite and nitrate concentrations were associated with injury Severity Score, suggesting that increased nitric oxide production in the brain is associated with injury severity and death. Hypothermia did not prevent the increase in cerebrospinal fluid nitrite and nitrate concentrations. Further study is required to determine the source of this increase in cerebrospinal fluid nitrite and nitrate concentrations and to further define the relationship to outcome and the effect of hypothermia on this process.

Nitrate and nitrite concentrations in human saliva: Variations with salivary flow-rate

P36: Nitrite and nitrate concentrations and metabolism in breast milk, artificial milk, and parenteral nutrition of term and preterm infants

Preliminary nitrite, nitrate and colour analysis of Malaysian edible bird’s nest

Changes in nitrate and nitrite concentrations over 24 h for sweet basil and scallions

Impact of food processing and storage conditions on nitrate content in canned vegetable-based infant foods.

Dietary nitrate has been reported to lower oxygen consumption in moderate- and severe-intensity exercise. To date, it is unproven that sodium nitrate (NaNO3(-); NIT) and nitrate-rich beetroot juice (BR) have the same effects on oxygen consumption, blood pressure, and plasma nitrate and nitrite concentrations or not. The aim of this study was to compare the effects of different dosages of NIT and BR on oxygen consumption in male athletes. Twelve healthy, well-trained men (median [minimum; maximum]; peak oxygen consumption: 59.4 mL·min(-1)·kg(-1) [40.5; 67.0]) performed 7 trials on different days, ingesting different nitrate dosages and placebo (PLC). Dosages were 3, 6, and 12 mmol nitrate as concentrated BR or NIT dissolved in plain water. Plasma nitrate and nitrite concentrations were measured before, 3 h after ingestion, and postexercise. Participants cycled for 5 min at moderate intensity and further 8 min at severe intensity. End-exercise oxygen consumption at moderate intensity was not significantly different between the 7 trials (p = 0.08). At severe-intensity exercise, end-exercise oxygen consumption was ~4% lower in the 6-mmol BR trial compared with the 6-mmol NIT (p = 0.003) trial as well as compared with PLC (p = 0.010). Plasma nitrite and nitrate concentrations were significantly increased after the ingestion of BR and NIT with the highest concentrations in the 12-mmol trials. Plasma nitrite concentration between NIT and BR did not significantly differ in the 6-mmol (p = 0.27) and in the 12-mmol (p = 0.75) trials. In conclusion, BR might reduce oxygen consumption to a greater extent compared with NIT.

P46: Low sodium nitrite (but not nitrate) concentrations attenuate MMP-9 production by endothelial cells

Our purpose was to evaluate whether maternal and fetal nitric oxide synthesis in pregnancies with small for gestational age (SGA) infants are different from those in pregnancies with appropriate for gestational age (AGA) infants. Maternal and fetal circulating nitrate and nitrite concentrations were compared between 30 pregnancies with AGA and 10 pregnancies with SGA at birth. End-products of nitric oxide synthesis were measured in maternal and cord venous blood samples using a fluorometric assay. Umbilical artery blood pH and PO2 were also measured. Maternal circulating nitrite and nitrate concentrations (6.91 +/- 1.27 microM) in pregnancies with SGA were significantly lower than those (11.69 +/- 1.33 microM) in pregnancies with AGA (P = 0.015). Fetal circulating nitrite and nitrate concentrations (7.54 +/- 1.09 microM) in pregnancies with SGA were also significantly lower than those (11.24 +/- 1.08 microM) in pregnancies with AGA (P = 0.024). There were no significant differences in umbilical artery blood pH and PO2 between the two groups. These results suggest that maternal and fetal nitric oxide synthesis are decreased in pregnancies with SGA infants.

The consumption of beetroot, a food rich in nitrate, has been recommended to enhance blood perfusion, restore endothelial function, and improve exercise performance. These properties may be explained by the possible effect of nitrate present in beetroot in stimulating the endogenous syn- thesis of nitric oxide, a potent vasodilator. However, there is limited evidence giving detailed information about how ni- trate contents from beetroot used in studies have been ana- lyzed. The purpose of this study was to evaluate nitrate and nitrite contentsofbeetrootfromdifferentregions ofBrazil and from the USA. Nitrate and nitrite contents were quantified by using a reversed-phase high-performance liquid chromatogra- phy system with fluorescence detection. Beetroots from the USA showed the highest nitrate (31.2±0.010 mmol.L �1 )a nd nitrite (0.45±0.005 mmol.L �1 ) contents when compared to beetroots from Brazil. Rio de Janeiro was the region that showed the highest nitrate content (17.1±0.020 mmol.L �1 ), while Rio Grande do Norte presented the highest nitrite con- tent (0.13±0.010 mmol.L �1 ). The reversed-phase high-perfor- mance liquid chromatography-fluorescence method may be applied for the quantification of nitrate and nitrite contents in beetroot samples. The results of the present study demonstrate that beetroots may vary in their nitrate and nitrite contents.

The influence of pollution from petroleum refining activities on the levels of nitrates and nitrites in five edible vegetable species was investigated. Besides, the kinetics of nitrite and nitrate was studied in vivo using albino rats with focus on the possible influence of concentration difference on kinetics and implications to toxicity. Leaf samples of the five vegetable species were collected randomly from various locations within Eleme, a host community of Port Harcourt Refinery Company and the Indorama Petrochemical Company. Also, samples were collected from Umuahia, which served as pollution-free control. The leaf samples were analyzed for their nitrite and nitrate contents. Nitrite was determined spectrophotometrically while nitrate was determined after cadmium column reduction. Results showed that samples from Eleme had higher mean nitrate (349.20 mg/100g dry leaf mass; P 0.05) as compared to the same samples from Umuahia. Solutions of nitrate and nitrite, equivalent in concentration to mean nitrate and nitrite content of the vegetable samples from the two locations were administered enterally to four groups of albino rats. Analysis of their blood levels were monitored five times at 30 minutes intervals following administration. Rates of change of blood nitrites and nitrates were found to be fairly constant in absorption as well as in the elimination phase. Their peak blood concentrations varied proportionately with their concentrations in administered solutions. However, peak blood nitrate was attained later in group of animals receiving higher amount of nitrate solution. Refining activities may pre-dispose people living within Eleme community to health hazards through contamination of edible vegetables.