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TSNA
Tobacco-specific nitrosamines (TSNAs) comprise one of the most important groups of carcinogens in tobacco products, particularly cigarettes (traditional and electronic) and fermented dipping snuff. Background These nitrosamine carcinogens are formed from nicotine and related compounds by a nitrosation reaction that occurs during the curing and processing of tobacco. Essentially the plant's natural alkaloids combine with nitrate forming the nitrosamines. They are called tobacco-specific nitrosamines because they are found only in tobacco products, and possibly in some other nicotine-containing products. 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. They are present in trace amounts in snus. They are important carcinogens in cigarette smoke, along with combustion ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrosamine
Nitrosamines (or more formally ''N''-nitrosamines) are organic compounds produced by industrial processes. The chemical structure is , where R is usually an alkyl group. Nitrosamines have a nitroso group () that are "probable human carcinogens", bonded to a deprotonated amine. Most nitrosamines are carcinogenic in animals. A 2006 systematic review supports a "positive association between nitrite and nitrosamine intake and gastric cancer, between meat and processed meat intake and gastric cancer and oesophageal cancer, and between preserved fish, vegetable and smoked food intake and gastric cancer, but is not conclusive". Chemistry The organic chemistry of nitrosamines is well developed with regard to their syntheses, their structures, and their reactions. They usually are produced by the reaction of nitrous acid () and secondary amines, although other nitrosyl sources (e.g. , , Alkyl nitrite, RONO) have the same effect: : The nitrous acid usually arises from protonation of a nit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nicotine-derived Nitrosamine Ketone
Nicotine-derived nitrosamine ketone (NNK) is one of the key tobacco-specific nitrosamines derived from nicotine. It plays an important role in carcinogenesis. The conversion of nicotine to NNK entails opening of the pyrrolidine ring. Synthesis and occurrence NNK can be produced by standard methods of organic synthesis. Tobacco NNK is both found in cured tobacco and is produced during its burning (pyrolysis). The amount of NNK delivered in cigarette smoke ranged from 30 to 280 ng/cigarette in one study and 12 to 110 ng/cigarette in another. Sun-cured tobaccos (a.k.a. "Oriental") contain very little NNK and other TSNAs due to low-nitrate soil, lack of nitrate fertilizer, and sun-curing. Flue-cured tobacco (a.k.a. "Virginia" tobacco), especially when using an open flame, contains most of the NNK in American blended tobaccos although Marlboro's "virginia blend" had the lowest levels of NNK per nicotine out of many tested with the exception of Natural American Spirit. e- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
N-Nitrosonornicotine
''N''-Nitrosonornicotine (NNN) is a tobacco-specific nitrosamine produced during the curing and processing of tobacco. Toxicity It has been classified as a List of IARC Group 1 carcinogens, Group 1 carcinogen. Although no adequate studies of the relationship between exposure to NNN and human cancer have been reported, there is sufficient evidence that NNN causes cancer in experimental animals. Sources NNN is found in a variety of tobacco products including smokeless tobacco like chewing tobacco and snuff (tobacco), snuff, cigarettes, and cigars. It is present in smoke from cigars and cigarettes, in the saliva of people who chew betel, betel quid with tobacco, and in the saliva of oral-snuff and e-cigarette users. NNN is produced by the nitrosation of nornicotine during the curing, aging, processing, and smoking of tobacco. Roughly half of the NNN originates in the unburnt tobacco, with the remainder being formed during burning. NNN can be produced in the acidic environment of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Snus
Snus (, ; ) is a Swedish smokeless tobacco, tobacco product. It is consumed by placing a pouch of powdered tobacco leaves under the lip for nicotine to be absorbed through the Mucous membrane, oral mucosa. Snus, not to be confused with Nicotine pouch, nicotine pouches, consists of ground up tobacco leaves, salt, an alkalizer (e.g. sodium carbonate, sodium bicarbonate) and (optionally) flavorings. The final product is sold as both loose tobacco, and in portions with the tobacco mixture contained in a small teabag-like pouch. The manufacturing process of snus differs from that of other oral tobacco products. Snus tobacco is heated and pasteurized rather than cured or fermented, resulting in a less harmful product which contains a lower concentration of TSNA carcinogens in comparison to other traditional tobacco products. Though research on the connection between snus and disease such as cancer is not conclusive, and some studies find no associations between snus consumptio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tobacco
Tobacco is the common name of several plants in the genus '' Nicotiana'' of the family Solanaceae, and the general term for any product prepared from the cured leaves of these plants. More than 70 species of tobacco are known, but the chief commercial crop is ''N. tabacum''. The more potent variant ''N. rustica'' is also used in some countries. Dried tobacco leaves are mainly used for smoking in cigarettes and cigars, as well as pipes and shishas. They can also be consumed as snuff, chewing tobacco, dipping tobacco, and snus. Tobacco contains the highly addictive stimulant alkaloid nicotine as well as harmala alkaloids. Tobacco use is a cause or risk factor for many deadly diseases, especially those affecting the heart, liver, and lungs, as well as many cancers. In 2008, the World Health Organization named tobacco use as the world's single greatest preventable cause of death. Etymology The English word 'tobacco' originates from the Spanish word ''taba ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol
A coxless four, abbreviated as a 4- and also called a straight four, is a racing shell used in the sport of competitive rowing. It is designed for four persons who propel the boat with sweep oars, without a coxswain. The crew consists of four rowers, each having one oar. There are two rowers on the stroke side (rower's right hand side) and two on the bow side (rower's lefthand side). As there is no coxswain, the rudder is controlled by one of the crew, normally with the rudder cable attached to the toe of one of their shoes which can pivot about the ball of the foot, moving the cable left or right. The steersman may row at bow, who has the best vision when looking over their shoulder, or on straighter courses stroke may steer, since they can point the stern of the boat at some landmark at the start of the course. The equivalent boat when it is steered by a coxswain is called a "coxed four". Racing boats (often called "shells") are long, narrow, and broadly semi-circular i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nicotine
Nicotine is a natural product, naturally produced alkaloid in the nightshade family of plants (most predominantly in tobacco and ''Duboisia hopwoodii'') and is widely used recreational drug use, recreationally as a stimulant and anxiolytic. As a pharmaceutical drug, it is used for smoking cessation to relieve drug withdrawal, withdrawal symptoms. Nicotine acts as a receptor agonist at most nicotinic acetylcholine receptors (nAChRs), except at two nicotinic receptor subunits (nAChRα9 and nAChRα10) where it acts as a receptor antagonist. Nicotine constitutes approximately 0.6–3.0% of the dry weight of tobacco. Nicotine is also present at Parts-per notation, ppb concentrations in edible plants in the family Solanaceae, including potatoes, tomatoes, and eggplants, though sources disagree on whether this has any biological significance to human consumers. It functions as an plant defense against herbivory, antiherbivore toxin; consequently, nicotine was widely used as an insecti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polycyclic Aromatic Hydrocarbons
A Polycyclic aromatic hydrocarbon (PAH) is any member of a class of organic compounds that is composed of multiple fused aromatic rings. Most are produced by the incomplete combustion of organic matter— by engine exhaust fumes, tobacco, incinerators, in roasted meats and cereals, or when biomass burns at lower temperatures as in forest fires. The simplest representative is naphthalene, having two aromatic rings, and the three-ring compounds anthracene and phenanthrene. PAHs are uncharged, non-polar and planar. Many are colorless. Many of them are also found in fossil fuel deposits such as coal and in petroleum. Exposure to PAHs can lead to different types of cancer, to fetal development complications, and to cardiovascular issues. Polycyclic aromatic hydrocarbons are discussed as possible starting materials for abiotic syntheses of materials required by the earliest forms of life. Nomenclature and structure The terms polyaromatic hydrocarbon, or polynuclear aromat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cancer Induction
Carcinogenesis, also called oncogenesis or tumorigenesis, is the formation of a cancer, whereby normal cells are transformed into cancer cells. The process is characterized by changes at the cellular, genetic, and epigenetic levels and abnormal cell division. Cell division is a physiological process that occurs in almost all tissues and under a variety of circumstances. Normally, the balance between proliferation and programmed cell death, in the form of apoptosis, is maintained to ensure the integrity of tissues and organs. According to the prevailing accepted theory of carcinogenesis, the somatic mutation theory, mutations in DNA and epimutations that lead to cancer disrupt these orderly processes by interfering with the programming regulating the processes, upsetting the normal balance between proliferation and cell death. This results in uncontrolled cell division and the evolution of those cells by natural selection in the body. Only certain mutations lead to cancer wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DNA Adduct
In molecular genetics, a DNA adduct is a segment of DNA bound to a Carcinogen, cancer-causing chemical. This process could lead to the development of cancerous cells, or carcinogenesis. DNA adducts in scientific experiments are used as biomarkers of exposure. They are especially useful in quantifying an organism's exposure to a carcinogen. The presence of such an adduct indicates prior exposure to a potential carcinogen, but it does not necessarily indicate the presence of cancer in the subject animal. DNA adducts are researched in laboratory settings. A typical experimental design for studying DNA adducts is to induce them with known carcinogens. A scientific journal will often incorporate the name of the carcinogen with their experimental design. For example, the term "DMBA-DNA adduct" in a scientific journal refers to a piece of DNA that has DMBA (7,12-dimethylbenz(a)anthracene) attached to it. Carcinogens' impact Several diseases, including cancer, develop from mutated DN ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oral Cancer
Oral cancer, also known as oral cavity cancer, tongue cancer or mouth cancer, is a cancer of the lining of the lips, mouth, or upper throat. In the mouth, it most commonly starts as a painless red or white patch, that thickens, gets ulcerated and continues to grow. When on the lips, it commonly looks like a persistent crusting ulcer that does not heal, and slowly grows. Other symptoms may include difficult or painful swallowing, new lumps or bumps in the neck, a swelling in the mouth, or a feeling of numbness in the mouth or lips. Risk factors include tobacco and alcohol use. Those who use both alcohol and tobacco have a 15 times greater risk of oral cancer than those who use neither. Other risk factors include betel nut chewing and sun exposure on the lip. HPV infection may play a limited role in some oral cavity cancers. Oral cancer is a subgroup of head and neck cancers. Diagnosis is made by sampling (biopsy) of the lesion, followed by an imaging workup (called staging) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Esophageal Cancer
Esophageal cancer (American English) or oesophageal cancer (British English) is cancer arising from the esophagus—the food pipe that runs between the throat and the stomach. Symptoms often include dysphagia, difficulty in swallowing and weight loss. Other symptoms may include odynophagia, pain when swallowing, a hoarseness, hoarse voice, Lymphadenopathy, enlarged lymph nodes ("glands") around the clavicle, collarbone, a dry cough, and possibly hemoptysis, coughing up or hematemesis, vomiting blood. The two main Histopathology, sub-types of the disease are esophageal squamous-cell carcinoma (often abbreviated to ESCC), which is more common in the developing world, and esophageal adenocarcinoma (EAC), which is more common in the developed world. A number of less common types also occur. Squamous-cell carcinoma arises from the squamous epithelium, epithelial cells that line the esophagus. Adenocarcinoma arises from glandular cells present in the lower third of the esophagus, ofte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
