Search results
Results from the WOW.Com Content Network
The effects of nitroso compounds vary dramatically across the gastrointestinal tract, and with diet. Nitroso compounds present in stool do not induce nitrosamine formation, because stool has neutral pH. [7] [8] Stomach acid catalyzes nitrosamine compound formation and is the main location of the reaction during digestion. [9]
In 1956, two British scientists, John Barnes and Peter Magee, reported that a simple member of the large class of N-nitrosamines, dimethylnitrosamine, produced liver tumours in rats. Subsequent studies showed that approximately 90% of the 300 nitrosamines tested were carcinogenic in a wide variety of animals. [15]
The tobacco-specific nitrosamines are present in cigarette smoke and to a lesser degree in "smokeless" tobacco products such as dipping tobacco and chewing tobacco; additional information has shown that trace amounts of NNN and NNK have been detected in e-cigarettes. [3] They are present in trace amounts in snus. They are important carcinogens ...
An alternative possible formation of diazonium and carbenium ions is through the enzymatic reaction of nitrosamines. [ 5 ] Typical accompanying symptoms during the medical cancer treatment via N -nitroso ureas are the impairment of bone marrow (damage of the stem cell compartment), lymphatic tissue and the gastrointestinal tract.
Main page; Contents; Current events; Random article; About Wikipedia; Contact us; Pages for logged out editors learn more
The mechanisms of carcinogenesis are not completely clear in humans. NMOR and its metabolites may induce DNA damage by directly forming reactive oxygen species or compounds which crosslink DNA. In a rat model in 2013, it was observed that NMOR is hydroxylated, probably by a P450 enzyme, alpha to the N-nitroso moiety. [17]
Indeed, (meta)stable nitrosation products (alkyl nitrites or nitrosamines) can also nitrosate under such conditions; and the equilibria can be driven in any desired direction. Absent a driving force, thionitrosos form out of nitrosamines, which form out of nitrite esters, which form out of nitrous acid. [3]
NNN is found in a variety of tobacco products including smokeless tobacco like chewing tobacco and snuff, [3] cigarettes, and cigars.It is present in smoke from cigars and cigarettes, in the saliva of people who chew betel quid with tobacco, and in the saliva of oral-snuff and e-cigarette [4] users.