12 rezultate
The kinetics of nornicotine and anabasine nitrosation, studied in aqueous solution, obeyed equations typical for the nitrosation of aliphatic secondary amines, with third-order stoichiometric rate constants of 1.15 (nornicotine) and 0.86 (anabasine) M-2 sec-1. The similarity of the two rate
The inhibition of estrogen biosynthesis by the use of aromatase inhibitors is emerging as a valuable approach to breast cancer therapy. Because smoking has a profound effect on estrogen-related processes we examined the ability of tobacco constituents to suppress estrogen production by breast cancer
In a study of the effect of N-n-octanoylnornicotine and other acyl derivatives of nornicotine on the aromatization of androstenedione by human placental microsomal aromatase, we found that N-n-octanoylnornicotine, a component of cigarette smoke, exhibited competitive inhibition with an apparent Ki
BACKGROUND
Snuff dipping as practiced in North America and Western Europe is causally associated with cancer of the oral cavity and pharynx. In the Sudan, natives use local Nicotiana rustica, a tobacco species with high levels of nicotine and nornicotine, to prepare their own snuff which they call
NNN is the first organic carcinogen isolated from unburned tobacco. It has been found in smoking tobaccos, chewing tobaccos and in snuff in concentrations between 0.3 and 90.0 mug. This appears to be an unusually high concentration for a nitrosamine in an environmental agent. We have presented data
Tobacco contains specific carcinogenic nitrosamines which are derived from nicotine. These compounds may be among the causative agents for the various cancers (lung, oral cavity, oesophagus, bladder and pancreas) which are associated with tobacco usage. The major tobacco specific nitrosamine is
Carcinogenic tobacco-specific nitrosamines are present in tobacco products and are believed to play a significant role in human cancers associated with tobacco use. Additional amounts of tobacco-specific nitrosamines could be formed endogenously. We tested this hypothesis by treating rats with
During tobacco processing and smoking, nicotine and nornicotine give rise to N'-nitrosonornicotine (NNN), a highly abundant, strong carcinogen. NNN is known to exert carcinogenic activity in mice, rats and hamsters. Major target organs for NNN carcinogenicity in the rat are the esophagus and the
Human data indicate an increased risk for cancer of the oral cavity for snuff dippers. Popular snuff products from the United States, Germany, Sweden, and Denmark were analyzed for tobacco-specific N-nitrosamines (TSNA). These compounds are formed during tobacco processing from nicotine,
N'-Nitrosonornicotine was added to the drinking water of outbred Sprague-Dawley rats. Adenocarcinomas of the olfactory epithelium occurred in all 15 rats, squamous papillomas o- the esophagus in 1, squamous papillomas of the nonglandular stomach in 1, and a hepatacellular tumor in 1. The possible
N'-Nitrosonornicotine (NNN) is one of the most abundant strong carcinogens in unburned tobacco and cigarette smoke and is classified by the International Agency for Research on Cancer as carcinogenic to humans. Human exposure to NNN mainly occurs upon use of tobacco products. It is also possible
Betel-quid ingredients were found to produce reactive oxygen species, such as superoxide anion and hydrogen peroxide, in vitro. We demonstrated that N'-nitrosonornicotine (NNN) can be converted to its active metabolite, hydrogen peroxide, nonenzymatically in the presence of ferrous ions and