Silymarin: A mixture of flavonoids extracted from seeds of the MILK THISTLE, Silybum marianum. It consists primarily of silybin and its isomers, silicristin and silidianin. Silymarin displays antioxidant and membrane stabilizing activity. It protects various tissues and organs against chemical injury, and shows potential as an antihepatoxic agent.Prostatic Neoplasms: Tumors or cancer of the PROSTATE.Prostate: A gland in males that surrounds the neck of the URINARY BLADDER and the URETHRA. It secretes a substance that liquefies coagulated semen. It is situated in the pelvic cavity behind the lower part of the PUBIC SYMPHYSIS, above the deep layer of the triangular ligament, and rests upon the RECTUM.Milk Thistle: The plant Silybum marianum in the family ASTERACEAE containing the bioflavonoid complex SILYMARIN. For centuries this has been used traditionally to treat liver disease. Silybum marianum (L.) Gaertn. = Carduus marianus L.Cell Line, Tumor: A cell line derived from cultured tumor cells.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.Mice, Nude: Mutant mice homozygous for the recessive gene "nude" which fail to develop a thymus. They are useful in tumor studies and studies on immune responses.Plasminogen Activator Inhibitor 1: A member of the serpin family of proteins. It inhibits both the tissue-type and urokinase-type plasminogen activators.1-Methyl-3-isobutylxanthine: A potent cyclic nucleotide phosphodiesterase inhibitor; due to this action, the compound increases cyclic AMP and cyclic GMP in tissue and thereby activates CYCLIC NUCLEOTIDE-REGULATED PROTEIN KINASESMedroxyprogesterone: (6 alpha)-17-Hydroxy-6-methylpregn-4-ene-3,20-dione. A synthetic progestational hormone used in veterinary practice as an estrus regulator.Plasminogen Inactivators: Important modulators of the activity of plasminogen activators. The inhibitors belong to the serpin family of proteins and inhibit both the tissue-type and urokinase-type plasminogen activators.Urokinase-Type Plasminogen Activator: A proteolytic enzyme that converts PLASMINOGEN to FIBRINOLYSIN where the preferential cleavage is between ARGININE and VALINE. It was isolated originally from human URINE, but is found in most tissues of most VERTEBRATES.Quinacrine: An acridine derivative formerly widely used as an antimalarial but superseded by chloroquine in recent years. It has also been used as an anthelmintic and in the treatment of giardiasis and malignant effusions. It is used in cell biological experiments as an inhibitor of phospholipase A2.Endotoxins: Toxins closely associated with the living cytoplasm or cell wall of certain microorganisms, which do not readily diffuse into the culture medium, but are released upon lysis of the cells.Confined Spaces: A space which has limited openings for entry and exit combined with unfavorable natural ventilation such as CAVES, refrigerators, deep tunnels, pipelines, sewers, silos, tanks, vats, mines, deep trenches or pits, vaults, manholes, chimneys, etc.Occupational Diseases: Diseases caused by factors involved in one's employment.Occupational Health: The promotion and maintenance of physical and mental health in the work environment.Occupational Health Services: Health services for employees, usually provided by the employer at the place of work.Toxicology: The science concerned with the detection, chemical composition, and biological action of toxic substances or poisons and the treatment and prevention of toxic manifestations.Database Management Systems: Software designed to store, manipulate, manage, and control data for specific uses.Occupational Medicine: Medical specialty concerned with the promotion and maintenance of the physical and mental health of employees in occupational settings.Magnesium Silicates: A generic term for a variety of compounds that contain silicon, oxygen, and magnesium, and may contain hydrogen. Examples include TALC and some kinds of ASBESTOS.Anilino Naphthalenesulfonates: A class of organic compounds which contain an anilino (phenylamino) group linked to a salt or ester of naphthalenesulfonic acid. They are frequently used as fluorescent dyes and sulfhydryl reagents.Salmonella typhimurium: A serotype of Salmonella enterica that is a frequent agent of Salmonella gastroenteritis in humans. It also causes PARATYPHOID FEVER.Mutagenicity Tests: Tests of chemical substances and physical agents for mutagenic potential. They include microbial, insect, mammalian cell, and whole animal tests.Benzene: Toxic, volatile, flammable liquid hydrocarbon byproduct of coal distillation. It is used as an industrial solvent in paints, varnishes, lacquer thinners, gasoline, etc. Benzene causes central nervous system damage acutely and bone marrow damage chronically and is carcinogenic. It was formerly used as parasiticide.Ethylene Oxide: A colorless and flammable gas at room temperature and pressure. Ethylene oxide is a bactericidal, fungicidal, and sporicidal disinfectant. It is effective against most micro-organisms, including viruses. It is used as a fumigant for foodstuffs and textiles and as an agent for the gaseous sterilization of heat-labile pharmaceutical and surgical materials. (From Reynolds, Martindale The Extra Pharmacopoeia, 30th ed, p794)4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid: An inhibitor of anion conductance including band 3-mediated anion transport.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.Micronucleus Tests: Induction and quantitative measurement of chromosomal damage leading to the formation of micronuclei (MICRONUCLEI, CHROMOSOME-DEFECTIVE) in cells which have been exposed to genotoxic agents or IONIZING RADIATION.Harmine: Alkaloid isolated from seeds of Peganum harmala L., Zygophyllaceae. It is identical to banisterine, or telepathine, from Banisteria caapi and is one of the active ingredients of hallucinogenic drinks made in the western Amazon region from related plants. It has no therapeutic use, but (as banisterine) was hailed as a cure for postencephalitic Parkinson disease in the 1920's.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.Skin Irritancy Tests: Tests or bioassays that measure the skin sensitization potential of various chemicals.Mass Spectrometry: An analytical method used in determining the identity of a chemical based on its mass using mass analyzers/mass spectrometers.Tandem Mass Spectrometry: A mass spectrometry technique using two (MS/MS) or more mass analyzers. With two in tandem, the precursor ions are mass-selected by a first mass analyzer, and focused into a collision region where they are then fragmented into product ions which are then characterized by a second mass analyzer. A variety of techniques are used to separate the compounds, ionize them, and introduce them to the first mass analyzer. For example, for in GC-MS/MS, GAS CHROMATOGRAPHY-MASS SPECTROMETRY is involved in separating relatively small compounds by GAS CHROMATOGRAPHY prior to injecting them into an ionization chamber for the mass selection.Spectrometry, Mass, Electrospray Ionization: A mass spectrometry technique used for analysis of nonvolatile compounds such as proteins and macromolecules. The technique involves preparing electrically charged droplets from analyte molecules dissolved in solvent. The electrically charged droplets enter a vacuum chamber where the solvent is evaporated. Evaporation of solvent reduces the droplet size, thereby increasing the coulombic repulsion within the droplet. As the charged droplets get smaller, the excess charge within them causes them to disintegrate and release analyte molecules. The volatilized analyte molecules are then analyzed by mass spectrometry.Patents as Topic: Exclusive legal rights or privileges applied to inventions, plants, etc.Conductometry: Determination of the quantity of a material present in a mixture by measurement of its effect on the electrical conductivity of the mixture. (Webster, 3d ed)Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization: A mass spectrometric technique that is used for the analysis of large biomolecules. Analyte molecules are embedded in an excess matrix of small organic molecules that show a high resonant absorption at the laser wavelength used. The matrix absorbs the laser energy, thus inducing a soft disintegration of the sample-matrix mixture into free (gas phase) matrix and analyte molecules and molecular ions. In general, only molecular ions of the analyte molecules are produced, and almost no fragmentation occurs. This makes the method well suited for molecular weight determinations and mixture analysis.Chromatography, Liquid: Chromatographic techniques in which the mobile phase is a liquid.Hair Preparations: Hair grooming, cleansing and modifying products meant for topical application to hair, usually human. They include sprays, bleaches, dyes, conditioners, rinses, shampoos, nutrient lotions, etc.Petroleum: Naturally occurring complex liquid hydrocarbons which, after distillation, yield combustible fuels, petrochemicals, and lubricants.Clothing: Fabric or other material used to cover the body.Interior Design and Furnishings: The planning of the furnishings and decorations of an architectural interior.BooksLice Infestations: Parasitic attack or subsistence on the skin by members of the order Phthiraptera, especially on humans by Pediculus humanus of the family Pediculidae. The hair of the head, eyelashes, and pubis is a frequent site of infestation. (From Dorland, 28th ed; Stedman, 26th ed)Drugs, Generic: Drugs whose drug name is not protected by a trademark. They may be manufactured by several companies.Therapeutic Equivalency: The relative equivalency in the efficacy of different modes of treatment of a disease, most often used to compare the efficacy of different pharmaceuticals to treat a given disease.Biosimilar Pharmaceuticals: BIOLOGIC PRODUCTS that are imitations but not exact replicas of innovator products.Therapies, Investigational: Treatments which are undergoing clinical trials or for which there is insufficient evidence to determine their effects on health outcomes; coverage for such treatments is often denied by health insurers.Awards and PrizesDiffusion of Innovation: The broad dissemination of new ideas, procedures, techniques, materials, and devices and the degree to which these are accepted and used.Interinstitutional Relations: The interactions between representatives of institutions, agencies, or organizations.

Dietary copper, manganese and iron affect the formation of aberrant crypts in colon of rats administered 3,2'-dimethyl-4-aminobiphenyl. (1/127)

Aberrant crypt foci (ACF) are preneoplastic lesions for colon cancer. Altered amounts of copper-zinc (CuZnSOD) and manganese (MnSOD) superoxide dismutases have been implicated in multistage carcinogesis of both rodents and humans. Dietary factors are potential modulators of both CuZnSOD and MnSOD activity. The purpose of this study was to investigate the interactive effects of dietary copper, manganese, and iron on 3,2'-dimethyl-4-aminobiphenyl (DMABP)-induced ACF and superoxide dismutase activities in weanling rats fed low or adequate copper (0.8 or 5.1 microg Cu/g diet), low or adequate manganese (0.6 or 17 microg Mn/g diet), and adequate or high iron (37 or 140 microg Fe/g diet). Twelve rats were allowed free access to each of these eight diets for 3.5 wk prior to DMABP administration and for an additional 8 wk after the first DMABP injection. Rats fed low dietary copper had 105% (P < 0.0001) higher formation of DMABP-induced ACF than those fed adequate dietary copper. Rats ingesting low rather than adequate dietary manganese had 23% higher formation of ACF, and rats ingesting high rather than adequate dietary iron had 18% higher formation of ACF. Heart total superoxide dismutase activity was significantly correlated with the number of ACF (r = -0.43, P < 0.0001) in rats administered DMABP. These results suggest that dietary alterations that affect superoxide dismutase activity may affect cancer susceptibility.  (+info)

Molecular and genetic damage from environmental tobacco smoke in young children. (2/127)

To assess the risks of early life exposure to environmental tobacco smoke (ETS), we tested whether four biomarkers in peripheral blood were associated with home ETS exposure in Hispanic and African-American children. The biomarkers included cotinine (a metabolite of nicotine) and three indicators of molecular and genetic damage from mutagens/carcinogens, protein adducts formed by the carcinogens 4-aminobiphenyl (4-ABP) and polycyclic aromatic hydrocarbons (PAHs), and sister chromatid exchanges (SCEs). We also explored possible ethnic differences in biomarkers. The study cohort comprised 109 Hispanic and African-American preschool children (1-6 years of age). Plasma cotinine was analyzed by gas chromatography, 4-ABP-hemoglobin adducts by gas chromatography-mass spectroscopy, PAH-albumin adducts by ELISA, and SCEs by cytogenetic techniques. Data on the amount of smoking by mothers (average 10.5 cigarettes per day) and other household members and regular visitors (average 6.5 cigarettes per day) were obtained by interview-administered questionnaires. Cotinine, 4-ABP-hemoglobin adducts, and PAH-albumin were significantly higher (P < 0.05) in the ETS-exposed children compared with the unexposed. SCEs were marginally higher (P = 0.076). African-American children had higher levels of cotinine (P = 0.059) and PAH-albumin (P = 0.02) than Hispanic children, after controlling for exposure to ETS. These results indicate molecular and genetic damage in minority children with  (+info)

Quantitative analysis of 4-aminobiphenyl-C8-deoxyguanosyl DNA adducts produced in vitro and in vivo using HPLC-ES-MS. (3/127)

Electrospray mass spectrometry (ES-MS) is a powerful tool for analysis of carcinogen-adducted DNA. In this study, we developed a quantitative isotope dilution method for analysis of N-(deoxyguanosine-8-yl)-4-aminobiphenyl (dG-C8-4-ABP), the principal nucleoside adduct derived from enzymatic hydrolysis of 4-aminobiphenyl (4-ABP)-modified DNA. The method used column switching valves to perform on-line sample concentration and cleanup, which permitted direct analysis of enzymatic DNA hydrolysates using narrow-bore liquid chromatography (LC). ES-MS detection was performed using a single quadrupole instrument by monitoring M+H+ and two fragment ions characteristic for dG-C8-4-ABP, along with M+H+ and a fragment ion for the deuterated internal standard. The detection limit for dG-C8-4-ABP in DNA hydrolysates was approximately 10 pg on-column, equivalent to 0.7 dG-C8-4-ABP adducts in 10(7) normal nucleotides for a sample containing 100 microg DNA. The method was applied to the analysis of calf thymus DNA modified in vitro through reaction with N-hydroxy-4-ABP and of hepatic DNA isolated from mice treated in vivo with two dose levels of 4-ABP.  (+info)

Human and Escherichia coli beta-glucuronidase hydrolysis of glucuronide conjugates of benzidine and 4-aminobiphenyl, and their hydroxy metabolites. (4/127)

Individuals exposed to carcinogenic aromatic amines excrete arylamine N- and O-glucuronide metabolites. This study assessed the susceptibility of selected glucuronides to hydrolysis by human and Escherichia coli beta-glucuronidase. N- or O-glucuronides were prepared with the following aglycones: benzidine, N-acetylbenzidine, N'-hydroxy-N-acetylbenzidine, N-hydroxy-N-acetylbenzidine, N-hydroxy-N,N'-diacetylbenzidine, 3-hydroxy-N,N'-diacetylbenzidine, 3-hydroxy-benzidine, 4-aminobiphenyl, N-hydroxy-4-aminobiphenyl, and N-hydroxy-N-acetyl-4-aminobiphenyl. The (3)H- and (14)C-labeled glucuronides were prepared with human or rat liver microsomes using UDP-glucuronic acid as cosubstrate. Each of the 10 glucuronides (6-12 microM) was incubated at pH 5.5 or 7.0 with either human recombinant (pure) or E. coli (commercial preparation) beta-glucuronidase for 30 min at 37 degrees C. Hydrolysis was measured by HPLC. Reaction conditions were optimized, using the O-glucuronide of N-hydroxy-N,N'-diacetylbenzidine. Both enzymes preferentially hydrolyzed O-glucuronides over N-glucuronides and distinguished between structural isomers. With E. coli beta-glucuronidase at pH 7.0, selectivity was demonstrated by the complete hydrolysis of N-hydroxy-N-acetyl-4-aminobiphenyl O-glucuronide in the presence of N-acetylbenzidine N-glucuronide, which was not hydrolyzed. Metabolism by both enzymes was completely inhibited by the specific beta-glucuronidase inhibitor saccharic acid-1,4-lactone (0.5 mM). The concentration of human beta-glucuronidase necessary to achieve significant hydrolysis of glucuronides was substantially more than the amount of enzyme reported previously to be present in urine under either normal or pathological conditions. The bacterial enzyme may hydrolyze O-glucuronides, but not N-glucuronides, in urine at neutral pH. Thus, the nonenzymatic hydrolysis of N-glucuronides by acidic urine is likely a more important source of free amine than enzymatic hydrolysis.  (+info)

CYP1A2 is not the primary enzyme responsible for 4-aminobiphenyl-induced hepatocarcinogenesis in mice. (5/127)

4-Aminobiphenyl (4-ABP), a potent carcinogen in rodents (liver cancer) and human (bladder cancer), is found as an environmental contaminant and in tobacco smoke. Hemoglobin adducts and lung DNA adducts of 4-ABP are found in tobacco smokers. In vitro metabolism studies with human and rat liver microsomes have shown that CYP1A2 is primarily responsible for catalyzing N-hydroxylation, the initial step in the metabolic activation of 4-ABP. To determine whether this P450 is a rate limiting pathway for hepatocarcinogenesis, CYP1A2-null mice were analyzed at 16 months of age and were compared with wild-type mice in their response to 4-ABP using the neonatal mouse bioassay and two different doses of the carcinogen. Overall differences in incidences of hepatocellular adenoma, carcinoma and preneoplastic foci were not significant between either genotypes or 4-ABP doses used, whereas small, but significant, differences were found for specific types of foci. These results suggest that while CYP1A2 levels may not be rate limiting for 4-ABP metabolism to produce tumors and foci, it may modulate the induction process of some types of liver foci in either a positive or negative manner. In vitro studies using CYP1A2-null and wild-type mouse liver microsomes revealed that CYP1A2 is not the sole P450 required for 4-ABP N-hydroxylation and that another, yet to be identified, P450 is likely to be involved.  (+info)

Mortalities of workers at the Nitro plant with exposure to 2-mercaptobenzothialzole. (6/127)

OBJECTIVES: An update of a study of workers exposed to 2-mercaptobenzothiazole (MBT) at a rubber chemicals plant in Nitro, West Virginia is reported. The earlier study found high rates of lung cancer, prostate cancer, and bladder cancer in these workers who also had potential exposure to 4-aminobiphenyl (PAB), a potent bladder carcinogen. METHODS: This cohort mortality study examines the mortalities of 1059 full time white male production workers employed at the plant from 1955 to 1977. A detailed exposure assessment was done on the 600 workers with exposure to MBT. Nine years of additional follow up to the previous study are added. RESULTS: It was found that MBT workers have expected rates of lung (standardised mortality ratio (SMR) = 1.0 95% confidence interval (95% CI) 0.7 to 1.5) and prostate (SMR = 0.9, 95% CI 0.2 to 2.3) cancer. There was an excess of bladder cancer among MBT workers who had definite exposure to PAB (SMR = 27.1, 95% CI 11.7 to 53.4), and MBT workers with potential exposure to PAB (SMR = 4.3, 95% CI 1.4 to 10.0). However, there were no deaths from bladder cancer among workers with no exposure to PAB (SMR = 0.0, 95% CI 0.0 to 24.7), although there were only 0.2 deaths expected. CONCLUSIONS: The potential confounding of exposure to an unknown portion of PAB in the MBT workers makes it impossible to evaluate risk of bladder cancer in this population at this time. However, exposure to MBT does not seem to increase the risk of most cancers including cancers of the lung and prostate.  (+info)

Redoxal as a new lead structure for dihydroorotate dehydrogenase inhibitors: a kinetic study of the inhibition mechanism. (7/127)

Mitochondrial dihydroorotate dehydrogenase (DHOdehase; EC is a target of anti-proliferative, immunosuppressive and anti-parasitic agents. Here, redoxal, (2,2'-[3,3'-dimethoxy[1, 1'-biphenyl]-4,4'-diyl)diimino]bis-benzoic acid, was studied with isolated mitochondria and the purified recombinant human and rat enzyme to find out the mode of kinetic interaction with this target. Its pattern of enzyme inhibition was different from that of cinchoninic, isoxazol and naphthoquinone derivatives and was of a non-competitive type for the human (K(ic)=402 nM; K(iu)=506 nM) and the rat enzyme (K(ic)=116 nM; K(iu)=208 nM). The characteristic species-related inhibition of DHOdehase found with other compounds was less expressed with redoxal. In human and rat mitochondria, redoxal did not inhibit NADH-induced respiration, its effect on succinate-induced respiration was marginal. This was in contrast to the sound effect of atovaquone and dichloroallyl-lawsone, studied here for comparison. In human mitochondria, the IC(50) value for the inhibition of succinate-induced respiration by atovaquone was 6.1 microM and 27.4 microM for the DHO-induced respiration; for dichlorallyl-lawsone, the IC(50) values were 14.1 microM and 0.23 microM.  (+info)

N-acetyltransferase 2 phenotype but not NAT1*10 genotype affects aminobiphenyl-hemoglobin adduct levels. (8/127)

Aminobiphenyls (ABPs) in tobacco have been implicated in bladder cancer etiology in smokers. N-Acetylation of ABPs in the liver, predominantly by the N-acetyltransferase 2 (NAT2) isozyme, represents a detoxification pathway, whereas O-acetylation of N-hydroxy-ABPs in the bladder, predominantly by the N-acetyltransferase 1 (NAT1) isozyme, represents a bioactivation pathway. We and others have demonstrated that NAT2 phenotype affects 3- and 4-ABP-hemoglobin adduct levels (higher levels in slow acetylators), which are considered valid biomarkers of the internal dose of ABP to the bladder. We have also shown that NAT1 genotype (NAT1*10 allele) is associated with increased DNA adduct levels in urothelial tissue and higher risk of bladder cancer among smokers. It is not known whether NAT1*10 genotype influences ABP-hemoglobin adduct levels. Therefore, we assessed 403 primarily non-Hispanic white residents of Los Angeles County for their NAT2 acetylator phenotype, NAT1*10 acetylator genotype, and 3- and 4-ABP-hemoglobin adduct levels. Eighty-two subjects were current tobacco smokers of varying intensities. Tobacco smokers had significantly higher mean 3- and 4-ABP-hemoglobin adduct levels relative to nonsmokers. The levels increased with increased amounts smoked per day (two-sided, P < 0.0001 in all cases). With adjustment for NAT1 genotype and race, the smoking-adjusted geometric mean level of 3-ABP-hemoglobin adducts in NAT2 slow acetylators was 47% higher than that in NAT2 rapid acetylators (P = 0.01). The comparable value for 4-ABP-hemoglobin adducts was 17% (P = 0.02). In contrast, no association between NAT1*10 genotype and 3- or 4 ABP-hemoglobin adduct levels was observed after adjustment for NAT2 phenotype, smoking, and race. The present study suggests that the impact of the NAT1*10 genotype on 3- and 4-ABP-hemoglobin adducts is noninformative on the possible association between NAT1 activity and bladder cancer risk.  (+info)

  • Twice as much nicotine is emitted in sidestream as in mainstream smoke, yet the carcinogen 4-aminobiphenyl is enriched about 30-fold in sidestream smoke. (
  • These include procedures for converting DNA adducts formed by 4-aminobiphenyl (92671), 4-aminofluorene (7083638), benzo(a)pyrene (50328), 4- (hydroxypyridyl)butanone, malondialdehyde (542789), 2- phosphoglycolate, and uracil (66228) into electrophores. (
  • With increasing demand for antioxidant supply in the food, honey had gained vitality since it is rich in phenolic compounds and other antioxidants like ascorbic acid, amino acids, and proteins. (
  • Considerable differences in both composition and content of phenolic compounds have been found in different unifloral honeys [ 18 ]. (
  • Compounds of the above formula I, in which R.sup.16 or R.sup.20 is an acidic substituent or a group COOP.sup.1, and pharmaceutical salts thereof, are useful as pharmaceuticals. (
  • Monitoring 4-aminobiphenyl (92671), 4-nitrobiphenyl (92933), and 4- dimethylaminoazobenzene (60117) in air was described. (
  • Due to the same cancer-causing compounds as Yellow #5, it causes tumors in the kidneys and adrenal glands of laboratory animals. (
  • However, on longer incubation, both the compounds were degraded further, resulting in reduction in toxicity and mutagenicity of the dye. (
  • Two monoclonal antisera, 4C11 and 3C8, recognizing 4-aminobiphenyl (4-ABP)--DNA adducts were developed and characterized by competitive enzyme-linked immunosorbent assay (ELISA). (
  • The enzyme related to the tumorigenicity of these compounds was characterized by a highly specific capacity to form adducts from the acetyl and propionyl derivatives. (
  • These findings suggest that the weak carcinogenicity of 3-aminobiphenyl may be attributed to the lack of genotoxicity of its N-hydroxyderivative, whereas in the case of 2-aminobiphenyl it may be due to the inability of the hepatic preparations to catalyse its N-hydroxylation, which is in agreement with published in vivo metabolic studies. (
  • Of the three isomers only 4-aminobiphenyl exhibited mutagenicity and only in the presence of an activation system. (
  • It is interesting that of the three isomers only 2-aminobiphenyl is non-planar, forming a dihedral angle of 40 degrees, and this may preclude it from acting as a substrate of the P-450I family of haemoproteins, which selectively catalyses the N-hydroxylation of many aromatic amines including 4-aminobiphenyl. (
  • 1 This study was partially supported by USPHS Grants CA-34627 and CA-48032 (to T. P. P.). A preliminary report of this work was presented at the annual meeting of the American Association for Cancer Research, March, 1995 (57) and the Sixth International Conference on Carcinogenic and Mutagenic N -Substituted Aryl Compounds, November, 1995 (58). (
  • Nitrate, which is introduced to the growing tobacco plant through the application of fertilizer, can be converted to ammonia, which, in turn, is converted to other nitrogenous organic compounds such as amino acids. (
  • Mechanisms involving steroid hormones seem plausible because there are fundamental gender differences in production and response to these compounds, and the androgen receptor (AR), estrogen receptors (ER), and progesterone receptors (PR) are expressed in the human bladder ( 7-12 ). (
  • Cyclooxygenase-2 expression is up-regulated by 2-aminobiphenyl in a ROS and MAPK-dependent signaling pathway in a bladder cancer cell line. (
  • In this study, we have demonstrated that 2-aminobiphenyl (2-ABP) up-regulated the expression of COX-2 in a dose- and time-dependent manner in TSGH-8301 bladder cancer cells. (
  • The figures below show the boiling and melting point for organic nitrogen compounds as amines, diamines, pyrroles, pyridines, piperidines and quinolines , together with the molecular structures of the different compounds. (
  • AAS are present in mainstream and side stream tobacco smoke, with the latter containing up to thirty times as much 4-aminobiphenyl (4-ABP) as mainstream smoke (Bryant MS, et al. (
  • Intermediate NH2 radicals, forming during the pyrolysis of ammonia during tobacco combustion, may react with aromatic CH groups (from compounds already present in the tobacco leaves) to form the AAs (Patrianakos, C., et. (