Evidence from animal studies indicates that various N-nitroso compounds are carcinogenic. We investigated whether consumption of foods and beverages containing nitrosodimethylamine, nitrites, and nitrates affected the risk of laryngeal, esophageal, and oral cancer. In a population-based case-control study in western Washington state, dietary consumption of these substances was measured in 645 c...

The aim of this study was to investigate the possible effects of sulphite oxidase (SOX, E.C. 1.8.3.1) deficiency on xenobiotic metabolism. For this purpose, SOX deficiency was produced in rats by the administration of a low molybdenum diet with concurrent addition of 200 ppm tungsten to their drinking water. First, hepatic SOX activity in deficient groups was measured to confirm SOX deficiency....

BACKGROUND The major potential site of acid nitrosation is the proximal stomach, an anatomical site prone to a rising incidence of metaplasia and adenocarcinoma. Nitrite, a pre-carcinogen present in saliva, can be converted to nitrosating species and N-nitroso compounds by acidification at low gastric pH in the presence of thiocyanate. AIMS To assess the effect of lipid and ascorbic acid on t...

A sensitive and selective method was developed and validated to detect six volatile nitrosamines (N-nitrosodimethylamine, N-nitrosomethylethylamine, N-nitrosodiethylamine, N-nitrosopiperidine, N-nitrosopyrrolidine and N-nitrosomorpholine) in human urine. This method uses a liquid-liquid extraction cartridge followed by analysis with gas chromatography-tandem mass spectrometry (GC-MS-MS) and qua...

Ozonation followed by biological activated carbon (O3/BAC) is being considered as a key component of reverse osmosis-free advanced treatment trains for potable wastewater reuse. Using a laboratory-scale O3/BAC system treating two nitrified wastewater effluents, this study characterized the effect of different ozone dosages (0-1.0 mg O3/mg dissolved organic carbon) and BAC empty bed contact time...

Metabolic activation may be a key step in determining the tissue specificity of carcinogenic nitrosamines. In previous work, we characterized P450IIE1 (an acetone/ethanol-inducible form of cytochrome P-450) as the major enzyme for the metabolic activation of N-nitrosodimethylamine. In this work, we investigated the metabolism of other N-nitrosodialkylamines in rat liver microsomes and in recons...

BACKGROUND Dietary N-nitroso compounds and endogenous nitrosation are important carcinogenic factors, but human evidence of their role is scarce for esophageal cancer and inconsistent for gastric cancer. OBJECTIVE We studied the relation between risks of esophageal and gastric cancer subtypes and dietary intake of N-nitrosodimethylamine, heme iron, nitrite, and nitrate in the Netherlands Coho...