Search results
Results from the WOW.Com Content Network
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]
Generally, people should not be exposed to a lifetime risk of cancer exceeding 1 in 100,000 from nitrosamines in their medicines. [12] EU regulators first became aware of nitrosamines in medicines in mid-2018, and took regulatory actions, including recalling medicines and stopping the use of active substances from certain manufacturers. [12]
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]
Among the tobacco-specific nitrosamines, nicotine-derived nitrosamine ketone (NNK) and N-nitrosonornicotine (NNN) are the most carcinogenic. [1] Others include N ′-nitrosoanatabine (NAT) and N-nitrosoanabasine (NAB). NNK and its metabolite 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) are potent systemic lung carcinogens in rats ...
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]
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]
In cigarette smoke, NNN has been found in levels between 2.2 and 6.6 parts per million (ppm). The FDA has put limits of nitrosamines in other consumable products (such as cured meats) at levels below 10 parts per billion (ppb). [14]
This article about an organic compound is a stub. You can help Wikipedia by expanding it.