The metabolism of nitrosamines by microsomal cytochrome P-450 (P-450) isozymes was studied in a reconstituted monooxygenase system. P-450 LM2, LM3a, LM3b and LM3c, LM4, and LM6 were purified, respectively, from the livers of phenobarbital-treated, ethanol-treated, untreated, isosafrole-treated, and imidazole-treated rabbits. Of these isozymes, LM3a had the highest N-nitrosodimethylamine demethy...

Nitrogenous disinfection by-products (N-DBPs) are far more cytotoxic and genotoxic than carbonaceous DBPs (Plewa & Wagner 2009). Among the N-DBPs, nitrosamines have been shown to be probable human carcinogens associated with 10–6 lifetime cancer risk at ng/L levels (USEPA 2002). An increasing number of water treatment plants (WTPs) in the United States have been using or considering chloraminat...

1. Problem Various starting substances and additives are needed to produce consumer products based on natural and synthetic rubber. They include vulcanisation accelerators from the group of dithiocarbamates and thiurames which are converted during the vulcanisation process into N-nitrosamines and nitrosatable amines. Migratable levels of N-nitrosamines and nitrosatable amines have been repeated...

Due to their high carcinogenicity, the control of nitrosamines, a group of disinfection by-products (DBPs), is an important issue for drinking water supplies. In this study, a method using ultra-performance liquid chromatography-electrospray ionization tandem mass spectrometry was improved for simultaneously analyzing nine nitrosamines in source water and finished water samples of twelve drinki...

A new method for the detection of indirect alkylating agents, such as the nitrosamines, using 3,4-dichlorothiophenol as t rapping agent in the presence of rat liver microsomes is reported. 3,4-Dichlorophenyl alkyl thioethers thus formed dur ing the incubation are detected by the use of a gas chromatography-mass spectrometry combinat ion unit and are quanti f ied by use of external standards. A ...

Bronchogenic carcinomas arise from bronchial epithelial cells (BECs). Inhalation exposure of BECs to nitrosamines in cigarette smoke is an important exogenous risk factor for malignant transformation of BECs. Thus, an important endogenous risk factor is likely to be the capacity of BECs to metabolize nitrosamines. Among the cytochrome P450 enzymes capable of metabolizing nitrosamines, CYP2A6, C...

A sensitive and selective method was developed and validated for the determination of nine N-nitrosamines in meat products. The N-nitrosamines were extracted with NaOH/methanol, partitioned into dichloromethane on a ChemElut column and cleaned-up by solid-phase extraction. All samples were spiked with (2)H isotope-labelled N-nitrosamine internal standard prior to extraction. After purification ...

Abstract. The atmospheric chemistry of organic nitrogen compounds (ONCs) is great importance for understanding the formation carcinogenic nitrosamines, and ONC oxidation products might influence aerosol particle growth. Indole a polyfunctional heterocyclic secondary amine with global emission quantity almost equivalent to that trimethylamine, highest emission. However, indole remains unclear. H...

Organic nitrogen (ON) compounds are present in atmospheric particulate matter (PM), but compared to their inorganic, hydrocarbon, and oxygenated counterparts, they are difficult to characterize due to their low concentrations in complex matrices. Nitrosamines are a class of ON compounds known to be highly carcinogenic and include species formed from nicotine degradation, but there are no detail...