Nitrosamines: A class of compounds that contain a -NH2 and a -NO radical. Many members of this group have carcinogenic and mutagenic properties.Butylhydroxybutylnitrosamine: A substituted carcinogenic nitrosamine.Dimethylnitrosamine: A nitrosamine derivative with alkylating, carcinogenic, and mutagenic properties. It causes serious liver damage and is a hepatocarcinogen in rodents.Carcinogens: Substances that increase the risk of NEOPLASMS in humans or animals. Both genotoxic chemicals, which affect DNA directly, and nongenotoxic chemicals, which induce neoplasms by other mechanism, are included.N-Nitrosopyrrolidine: Carcinogenic nitrosamine that may be formed from preservatives in meats during their preparation or in the liver during metabolism.Sulfadimethoxine: A sulfanilamide that is used as an anti-infective agent.Rubber: A high-molecular-weight polymeric elastomer derived from the milk juice (LATEX) of HEVEA brasiliensis and other trees and plants. It is a substance that can be stretched at room temperature to at least twice its original length and after releasing the stress, retract rapidly, and recover its original dimensions fully.Rats, Inbred F344Diethylnitrosamine: A nitrosamine derivative with alkylating, carcinogenic, and mutagenic properties.Tobacco: A plant genus of the family SOLANACEAE. Members contain NICOTINE and other biologically active chemicals; its dried leaves are used for SMOKING.Plants, Toxic: Plants or plant parts which are harmful to man or other animals.Urinary Bladder Neoplasms: Tumors or cancer of the URINARY BLADDER.Tobacco, Smokeless: Powdered or cut pieces of leaves of NICOTIANA TABACUM which are inhaled through the nose, chewed, or stored in cheek pouches. It includes any product of tobacco that is not smoked.Nitrites: Salts of nitrous acid or compounds containing the group NO2-. The inorganic nitrites of the type MNO2 (where M=metal) are all insoluble, except the alkali nitrites. The organic nitrites may be isomeric, but not identical with the corresponding nitro compounds. (Grant & Hackh's Chemical Dictionary, 5th ed)Biotransformation: The chemical alteration of an exogenous substance by or in a biological system. The alteration may inactivate the compound or it may result in the production of an active metabolite of an inactive parent compound. The alterations may be divided into METABOLIC DETOXICATION, PHASE I and METABOLIC DETOXICATION, PHASE II.Cocarcinogenesis: The combination of two or more different factors in the production of cancer.DimethylaminesNitroso CompoundsTars: Viscous materials composed of complex, high-molecular-weight compounds derived from the distillation of petroleum or the destructive distillation of wood or coal. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Cytochrome P-450 CYP2E1: An ethanol-inducible cytochrome P450 enzyme that metabolizes several precarcinogens, drugs, and solvents to reactive metabolites. Substrates include ETHANOL; INHALATION ANESTHETICS; BENZENE; ACETAMINOPHEN and other low molecular weight compounds. CYP2E1 has been used as an enzyme marker in the study of alcohol abuse.Opisthorchiasis: Infection with flukes of the genus Opisthorchis.Neoplasms, Experimental: Experimentally induced new abnormal growth of TISSUES in animals to provide models for studying human neoplasms.Nitrates: Inorganic or organic salts and esters of nitric acid. These compounds contain the NO3- radical.SmokeNose Neoplasms: Tumors or cancer of the NOSE.United States Federal Trade Commission: An independent administrative agency concerned with maintaining competitive free enterprise by prohibiting unfair methods of competition and unfair deceptive acts or practices.Food Preservation: Procedures or techniques used to keep food from spoiling.Meat Products: Articles of food which are derived by a process of manufacture from any portion of carcasses of any animal used for food (e.g., head cheese, sausage, scrapple).Nicotine: Nicotine is highly toxic alkaloid. It is the prototypical agonist at nicotinic cholinergic receptors where it dramatically stimulates neurons and ultimately blocks synaptic transmission. Nicotine is also important medically because of its presence in tobacco smoke.Erythrocebus patas: A species of the genus ERYTHROCEBUS, subfamily CERCOPITHECINAE, family CERCOPITHECIDAE. It inhabits the flat open arid country of Africa. It is also known as the patas monkey or the red monkey.ButanonesUrinary Bladder Calculi: Stones in the URINARY BLADDER; also known as vesical calculi, bladder stones, or cystoliths.Urinary Bladder: A musculomembranous sac along the URINARY TRACT. URINE flows from the KIDNEYS into the bladder via the ureters (URETER), and is held there until URINATION.Isothiocyanates: Organic compounds with the general formula R-NCS.Silica Gel: A non-crystalline form of silicon oxide that has absorptive properties. It is commonly used as a desiccating agent and as a stationary phase for CHROMATOGRAPHY. The fully hydrated form of silica gel has distinct properties and is referred to as SILICIC ACID.Aminopyrine: A pyrazolone with analgesic, anti-inflammatory, and antipyretic properties but has risk of AGRANULOCYTOSIS. A breath test with 13C-labeled aminopyrine has been used as a non-invasive measure of CYTOCHROME P-450 metabolic activity in LIVER FUNCTION TESTS.Mutagens: Chemical agents that increase the rate of genetic mutation by interfering with the function of nucleic acids. A clastogen is a specific mutagen that causes breaks in chromosomes.Cotinine: The N-glucuronide conjugate of cotinine is a major urinary metabolite of NICOTINE. It thus serves as a biomarker of exposure to tobacco SMOKING. It has CNS stimulating properties.Sodium Nitrite: Nitrous acid sodium salt. Used in many industrial processes, in meat curing, coloring, and preserving, and as a reagent in ANALYTICAL CHEMISTRY TECHNIQUES. It is used therapeutically as an antidote in cyanide poisoning. The compound is toxic and mutagenic and will react in vivo with secondary or tertiary amines thereby producing highly carcinogenic nitrosamines.Legislation, Food: Laws and regulations concerned with industrial processing and marketing of foods.Food Additives: Substances which are of little or no nutritive value, but are used in the processing or storage of foods or animal feed, especially in the developed countries; includes ANTIOXIDANTS; FOOD PRESERVATIVES; FOOD COLORING AGENTS; FLAVORING AGENTS; ANTI-INFECTIVE AGENTS (both plain and LOCAL); VEHICLES; EXCIPIENTS and other similarly used substances. Many of the same substances are PHARMACEUTIC AIDS when added to pharmaceuticals rather than to foods.Volatilization: A phase transition from liquid state to gas state, which is affected by Raoult's law. It can be accomplished by fractional distillation.Food Analysis: Measurement and evaluation of the components of substances to be taken as FOOD.Pyridines: Compounds with a six membered aromatic ring containing NITROGEN. The saturated version is PIPERIDINES.Respiratory Tract NeoplasmsDNA Adducts: The products of chemical reactions that result in the addition of extraneous chemical groups to DNA.Lung Neoplasms: Tumors or cancer of the LUNG.Anticarcinogenic Agents: Agents that reduce the frequency or rate of spontaneous or induced tumors independently of the mechanism involved.Mesocricetus: A genus of the family Muridae having three species. The present domesticated strains were developed from individuals brought from Syria. They are widely used in biomedical research.GuanineCarcinoma, Transitional Cell: A malignant neoplasm derived from TRANSITIONAL EPITHELIAL CELLS, occurring chiefly in the URINARY BLADDER; URETERS; or RENAL PELVIS.Meat: The edible portions of any animal used for food including domestic mammals (the major ones being cattle, swine, and sheep) along with poultry, fish, shellfish, and game.Beer: An alcoholic beverage usually made from malted cereal grain (as barley), flavored with hops, and brewed by slow fermentation.Polycyclic Hydrocarbons, Aromatic: A major group of unsaturated cyclic hydrocarbons containing two or more rings. The vast number of compounds of this important group, derived chiefly from petroleum and coal tar, are rather highly reactive and chemically versatile. The name is due to the strong and not unpleasant odor characteristic of most substances of this nature. (From Hawley's Condensed Chemical Dictionary, 12th ed, p96)p-Dimethylaminoazobenzene: A reagent used mainly to induce experimental liver cancer. According to the Fourth Annual Report on Carcinogens (NTP 85-002, p. 89) published in 1985, this compound "may reasonably be anticipated to be a carcinogen." (Merck, 11th ed)Mutagenicity Tests: Tests of chemical substances and physical agents for mutagenic potential. They include microbial, insect, mammalian cell, and whole animal tests.Smoking: Inhaling and exhaling the smoke of burning TOBACCO.Alkylating Agents: Highly reactive chemicals that introduce alkyl radicals into biologically active molecules and thereby prevent their proper functioning. Many are used as antineoplastic agents, but most are very toxic, with carcinogenic, mutagenic, teratogenic, and immunosuppressant actions. They have also been used as components in poison gases.Glucuronates: Derivatives of GLUCURONIC ACID. Included under this heading are a broad variety of acid forms, salts, esters, and amides that include the 6-carboxy glucose structure.Microsomes, Liver: Closed vesicles of fragmented endoplasmic reticulum created when liver cells or tissue are disrupted by homogenization. They may be smooth or rough.Liver Neoplasms, Experimental: Experimentally induced tumors of the LIVER.Aryl Hydrocarbon Hydroxylases: A large group of cytochrome P-450 (heme-thiolate) monooxygenases that complex with NAD(P)H-FLAVIN OXIDOREDUCTASE in numerous mixed-function oxidations of aromatic compounds. They catalyze hydroxylation of a broad spectrum of substrates and are important in the metabolism of steroids, drugs, and toxins such as PHENOBARBITAL, carcinogens, and insecticides.Hydroxylation: Placing of a hydroxyl group on a compound in a position where one did not exist before. (Stedman, 26th ed)Mixed Function Oxygenases: Widely distributed enzymes that carry out oxidation-reduction reactions in which one atom of the oxygen molecule is incorporated into the organic substrate; the other oxygen atom is reduced and combined with hydrogen ions to form water. They are also known as monooxygenases or hydroxylases. These reactions require two substrates as reductants for each of the two oxygen atoms. There are different classes of monooxygenases depending on the type of hydrogen-providing cosubstrate (COENZYMES) required in the mixed-function oxidation.Methylnitrosourea: A nitrosourea compound with alkylating, carcinogenic, and mutagenic properties.Esophageal Neoplasms: Tumors or cancer of the ESOPHAGUS.Microsomes: Artifactual vesicles formed from the endoplasmic reticulum when cells are disrupted. They are isolated by differential centrifugation and are composed of three structural features: rough vesicles, smooth vesicles, and ribosomes. Numerous enzyme activities are associated with the microsomal fraction. (Glick, Glossary of Biochemistry and Molecular Biology, 1990; from Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)Papilloma: A circumscribed benign epithelial tumor projecting from the surrounding surface; more precisely, a benign epithelial neoplasm consisting of villous or arborescent outgrowths of fibrovascular stroma covered by neoplastic cells. (Stedman, 25th ed)Hyperplasia: An increase in the number of cells in a tissue or organ without tumor formation. It differs from HYPERTROPHY, which is an increase in bulk without an increase in the number of cells.Tobacco Smoke Pollution: Contamination of the air by tobacco smoke.Precancerous Conditions: Pathological processes that tend eventually to become malignant. (From Dorland, 27th ed)Nitrosation: Conversion into nitroso compounds. An example is the reaction of nitrites with amino compounds to form carcinogenic N-nitrosamines.