Disease relevance of NO-Pro

• Urinary excretion levels of nitrate and N-nitrosoproline were determined in 160 individuals in a Colombian population at high risk for gastric cancer [1].
• A highly significant correlation (r = 0.56, P = 0.0002) was noted for urinary nitrate and N-nitrosoproline excretion in individuals with intestinal metaplasia and dysplasia [1].
• Studies of the disappearance of nitrosoproline from the circulating plasma indicated an apparent volume of distribution of 52% of the total body weight, suggesting some penetration by the compound into the intracellular space [2].
• N-nitrosoproline excretion in the presence and absence of gastric disease [3].
• By applying the nitrosoproline (NPRO) test in ecological studies on esophageal cancer causation in China some support was obtained for the involvement of N-nitroso compounds [4].

High impact information on NO-Pro

• Extracts of betel nut (Areca catechu) were tested for their capacity to inhibit the endogenous formation of nitrosamines by measurement of the amount of urinary N-nitroso-L-proline (NPRO) following ingestion of sodium nitrate (300 mg) and L-proline (300 mg) by 2 volunteers [5].
• Excretion of N-nitrosoproline in 12-h overnight urine after intake of 500-mg L-proline was used to quantify the rate of endogenous nitrosation in 285 individuals in an area in northern Denmark with large variation in nitrate concentration of the drinking water [6].
• Gas chromatography-high resolution mass spectrometry methods were developed for quantifying nitrosodimethylamine (NDMA) and nitrosoproline (NPRO) in human urine [7].
• Endogenous formation of N-nitrosoproline using the NPRO-test was determined in two groups with low (healthy control and proximal gastral vagotomy patients) and high (Billroth I and II patients) gastric nitrite concentrations [8].
• In this group, nitrosoproline excretion was highly correlated with nitrate excretion in the subpopulation with advanced gastric pathology, but not in control subpopulations with more normal stomachs [9].

Chemical compound and disease context of NO-Pro

• The levels of nitrite, N-nitrosoproline and total N-nitroso compounds, when expressed as the amount per mol creatinine, were also significantly increased in patients with bacteriuria [10].
• Comparison of urinary nitrate, N-nitrosoproline, 7-methylguanine and 3-methyladenine levels in a human population at risk for gastric cancer [11].
• We have measured the urinary excretion of nitrate, N-nitrosoproline, 3-methyladenine and 7-methylguanine in a human population at high risk for gastric cancer [11].

Biological context of NO-Pro

• Quantitative estimation of endogenous nitrosation in humans by monitoring N-nitrosoproline excreted in the urine [12].
• The NPRO test has been applied to human subjects in clinical and epidemiological studies, and the kinetics and dietary modifiers of endogenous nitrosation have been investigated [13].
• An alkaline hydrolysis method is described for the release of bound N-nitrosoproline (NPRO) from cured meats that is more efficient than an enzymic method reported previously [14].
• Urinary nitrosoproline excretion as an index of in vivo nitrosamine formation was shown to be unaffected by bacterial decontamination of the alimentary tract, and proceeded in the absence of detectable nitrate reductase activity in the intestinal contents [15].
• Endogenous formation of N-nitrosoproline upon cigarette smoke inhalation [16].

Anatomical context of NO-Pro

• In order to resolve this controversy, we have assessed endogenous nitrosation by the independent N-nitrosoproline excretion test in subjects who had previously undergone gastric juice analysis by one of these methods [17].
• Results obtained after application of the NPRO test to subjects at high risk for cancers of the stomach, oesophagus, oral cavity and urinary bladder are summarized [13].
• Results obtained after application of the NPRO test to subjects at high risk for cancers of the stomach, esophagus, oral cavity and urinary bladder are summarized [18].
• The metabolism of the non-carcinogenic N-nitrosoproline (NPRO) was investigated in vitro using both S9 preparations and isolated hepatocytes from F344 rats [19].
• Metabolic studies of 15N-labeled N-nitrosoproline in isolated rat hepatocytes and subcellular fractions [19].

Associations of NO-Pro with other chemical compounds

• Nitrate exposure was assessed by measurement of urinary nitrate excretion over 12 hr, and endogenous nitrosation was assessed using the N-nitrosoproline test (NPRO-test) [20].
• Studies with human volunteers showed inhibiting effects of intake of ascorbic acid and green tea consumption on nitrosation using the N-nitrosoproline test [21].
• The syn and anti conformers of N-nitrosoproline, N-nitrososarcosine and N-nitroso-2-(ethylamino)-ethanol, have been separated by liquid chromatography [22].
• In the second system, the volatile methyl ester of the intact nitrosoproline is prepared, then detected by gas-liquid chromatography (GLC), and confirmed by combined gas-liquid chromatography and mass spectrometry (GLC-MS) [23].
• These data suggest that L-proline, after endogenous nitrosation, became nitrosoproline and suppressed CA, and that, as a result of in vivo nitrosation of tyramine and MTCAs, they became mutagenic nitroso compounds showing positive results [24].

Gene context of NO-Pro

• N-Nitrosoproline (NPRO) and eighteen other N-nitrosodialkylamines were irradiated with UVA in the presence of phi X174 RFI DNA [25].
• Effects of N-nitrosopyrrolidine and N-nitrosoproline on the incorporation of 3H-thymidine into the DNA of various organs of the mouse: tissue specificity and effects of ethanol consumption [26].

Analytical, diagnostic and therapeutic context of NO-Pro

• To elucidate the factors governing the formation of N-nitrosamines in the stomach, the formation of N-nitrosoproline (NPro) was studied under controlled conditions, using a dog equipped with a Thomas cannula [27].
• N-nitrosoproline (NPRO) excretion, an indicator of endogenous nitrosation, was measured in a group of hospital inpatients who were identified by endoscopy and gastric biopsy as either having gastric lesions or having healthy stomachs [3].
• High-performance liquid chromatography of N-nitrosoproline in urine [28].
• 2. Decreased urinary excretion of N-nitrosoproline (NPRO) was observed in rats fed on fat-supplemented diets compared with those fed on low-fat diets, with butterfat having the greatest effect of the fats tested [29].
• Patients who had undergone a Billroth II gastrectomy (PG) or had pernicious anaemia (PA) and healthy matched control subjects (MC) participated in 24-h studies in which bacteria, nitrite and N-nitroso compounds (NOC) were measured in gastric juice and N-nitrosoproline (NPRO) in urine [30].

References