Lior Z. Braunstein, MD; Elizabeth D. Kantor, PhD; Kelli O’Connell, MSPHc; Amber Jessop Hudspeth, MSc; Qian Wu, Nicola Zenzola, David Y. Light, BSc

The rates of elimination of N-nitrosodimethylamine (NDMA) and its fully deuterated analogue (N-nitrosodi[2H6]methylamine, [2H6]NDMA) were studied in vivo to explore the origins of the difference in their carcinogenicity. Male Fischer 344 rats, 7.5 weeks of age, were given nitrosamine bolus doses of 1.35 mumol/kg by tail vein injection and 2.02 or 4.05 mumol/kg by p.o. gavage. Animals were sacri...

Short-term exposure to diethyl ether strongly inhibits the metabolism of N-nitrosodimethylamine (NDMA). Twenty-six 6-week-old male Fischer 344 rats were exposed to ether vapor until their righting reflex was lost (approximately 2 min). The animals were removed from the ether and NDMA was immediately administered by i.v. bolus injection at a dose of 300 microgram/kg via a cannula surgically inse...

The water contaminant N-nitrosodimethylamine (NDMA) is a probable human carcinogen whose appearance in the environment is related to the release of rocket fuel and to chlorine-based disinfection of water and wastewater. Although this compound has been shown to be biodegradable, there is minimal information about the organisms capable of this degradation, and little is understood of the mechanis...

This study investigates two aspects of NDMA formation reactions: (i) evaluation of the potential effect of formaldehyde on NDMA formation, particularly in reactions of dimethylamine (DMA) and nitrite, and (ii) assessment of potential NDMA formation from a range of polymeric coagulants and flocculants upon exposure to disinfection oxidants. The results show that the presence of formaldehyde can ...

N-Nitrosodimethylamine (NDMA) is a potent carcinogen and an emerging contaminant in groundwater and drinking water. The metabolism of NDMA in mammalian cells has been widely studied, but little information is available concerning the microbial transformation of this compound. The objective of this study was to elucidate the pathway(s) of NDMA biotransformation by Pseudomonas mendocina KR1, a st...

Aberrant crypt foci can be identified in the colons of rodents treated 3 wk earlier with azoxymethane, a known colon carcinogen. These crypts can easily be visualized in the unsectioned methylene blue-stained colons under light microscopy, where they are distinguished by their increased size, more prominent epithelial cells, and pericryptal space. They occur as single aberrant crypts or as two,...

The metabolism of several N-nitrosamines (N-nitrosodimethylamine, N-nitrosoethylmethylamine, N-nitrosodiethylamine, N-nitrosobenzylmethylamine, and N-nitrosopyrrolidine) in cultured human and rat esophagus has been investigated by measuring (a) CO2, (b) metabolites with an oxo group, and (c) metabolites bound to DNA. Both acyclic and cyclic N-nitrosamines were metabolized by rat esophagus. The ...

We examined the potential for the widely consumed xenobiotic ethanol to transplacentally induce fetal rat CYP2E1. Throughout gestation, rat dams were fed a liquid diet containing 5% ethanol or two separate control diets. At 2 days before term, the dams were killed, and maternal and embryonic tissues were collected. Immunoblot analysis of microsomes from fetal liver, placenta and maternal brain ...