Benzo(a)pyrene: A potent mutagen and carcinogen. It is a public health concern because of its possible effects on industrial workers, as an environmental pollutant, an as a component of tobacco smoke.Pyrenes: A group of condensed ring hydrocarbons.7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide: 7,8,8a,9a-Tetrahydrobenzo(10,11)chryseno (3,4-b)oxirene-7,8-diol. A benzopyrene derivative with carcinogenic and mutagenic activity.Benzopyrenes: A class of chemicals that contain an anthracene ring with a naphthalene ring attached to it.Dihydroxydihydrobenzopyrenes: Benzopyrenes saturated in any two adjacent positions and substituted with two hydroxyl groups in any position. The majority of these compounds have carcinogenic or mutagenic activity.Benzopyrene Hydroxylase: A drug-metabolizing, cytochrome P-448 (P-450) enzyme which catalyzes the hydroxylation of benzopyrene to 3-hydroxybenzopyrene in the presence of reduced flavoprotein and molecular oxygen. Also acts on certain anthracene derivatives. An aspect of EC 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)DNA Adducts: The products of chemical reactions that result in the addition of extraneous chemical groups to DNA.Polycyclic Compounds: Compounds consisting of two or more fused ring structures.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.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.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.Epoxy Compounds: Organic compounds that include a cyclic ether with three ring atoms in their structure. They are commonly used as precursors for POLYMERS such as EPOXY RESINS.Methylcholanthrene: A carcinogen that is often used in experimental cancer studies.Benz(a)Anthracenes: Four fused benzyl rings with three linear and one angular, that can be viewed as a benzyl-phenanthrenes. Compare with NAPHTHACENES which are four linear rings.Mutagenicity Tests: Tests of chemical substances and physical agents for mutagenic potential. They include microbial, insect, mammalian cell, and whole animal tests.Cytochrome P-450 CYP1A1: A liver microsomal cytochrome P-450 monooxygenase capable of biotransforming xenobiotics such as polycyclic hydrocarbons and halogenated aromatic hydrocarbons into carcinogenic or mutagenic compounds. They have been found in mammals and fish. This enzyme, encoded by CYP1A1 gene, can be measured by using ethoxyresorufin as a substrate for the ethoxyresorufin O-deethylase activity.Coal Tar: A by-product of the destructive distillation of coal used as a topical antieczematic. It is an antipruritic and keratoplastic agent used also in the treatment of psoriasis and other skin conditions. Occupational exposure to soots, tars, and certain mineral oils is known to be carcinogenic according to the Fourth Annual Report on Carcinogens (NTP 85-002, 1985) (Merck Index, 11th ed).Glycols: A generic grouping for dihydric alcohols with the hydroxy groups (-OH) located on different carbon atoms. They are viscous liquids with high boiling points for their molecular weights.Benzoflavones: Organic compounds containing a BENZENE ring attached to a flavone group. Some of these are potent arylhydrocarbon hydroxylase inhibitors. They may also inhibit the binding of NUCLEIC ACIDS to BENZOPYRENES and related compounds. The designation includes all isomers; the 7,8-isomer is most frequently encountered.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.Carcinogens, Environmental: Carcinogenic substances that are found in the environment.Chrysenes: 1,2-Benzphenanthrenes. POLYCYCLIC COMPOUNDS obtained from coal tar.Antimutagenic Agents: Agents that reduce the frequency or rate of spontaneous or induced mutations independently of the mechanism involved.Cytochrome P-450 Enzyme System: A superfamily of hundreds of closely related HEMEPROTEINS found throughout the phylogenetic spectrum, from animals, plants, fungi, to bacteria. They include numerous complex monooxygenases (MIXED FUNCTION OXYGENASES). In animals, these P-450 enzymes serve two major functions: (1) biosynthesis of steroids, fatty acids, and bile acids; (2) metabolism of endogenous and a wide variety of exogenous substrates, such as toxins and drugs (BIOTRANSFORMATION). They are classified, according to their sequence similarities rather than functions, into CYP gene families (>40% homology) and subfamilies (>59% homology). For example, enzymes from the CYP1, CYP2, and CYP3 gene families are responsible for most drug metabolism.PhenanthrenesStereoisomerism: The phenomenon whereby compounds whose molecules have the same number and kind of atoms and the same atomic arrangement, but differ in their spatial relationships. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)Spectrometry, Fluorescence: Measurement of the intensity and quality of fluorescence.DNA: A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).Biodegradation, Environmental: Elimination of ENVIRONMENTAL POLLUTANTS; PESTICIDES and other waste using living organisms, usually involving intervention of environmental or sanitation engineers.Creosote: A greasy substance with a smoky odor and burned taste created by high temperature treatment of BEECH and other WOOD; COAL TAR; or resin of the CREOSOTE BUSH. It contains CRESOLS and POLYCYCLIC AROMATIC HYDROCARBONS which are CARCINOGENS. It has been widely used as wood preservative and in PESTICIDES and had former use medicinally in DISINFECTANTS; LAXATIVES; and DERMATOLOGIC AGENTS.Trichloroepoxypropane: A potent epoxide hydrase and aryl hydrocarbon hydroxylase inhibitor. It enhances the tumor-initiating ability of certain carcinogens.beta-Naphthoflavone: A polyaromatic hydrocarbon inducer of P4501A1 and P4501A2 cytochromes. (Proc Soc Exp Biol Med 1994 Dec:207(3):302-308)Aroclors: Industrial chemicals which have become widespread environmental pollutants. Each aroclor is a mixture of chlorinated biphenyls (1200 series) or chlorinated terphenyls (5400 series) or a combination of both (4400 series).Epoxide Hydrolases: Enzymes that catalyze reversibly the formation of an epoxide or arene oxide from a glycol or aromatic diol, respectively.Receptors, Aryl Hydrocarbon: Cytoplasmic proteins that bind certain aryl hydrocarbons, translocate to the nucleus, and activate transcription of particular DNA segments. AH receptors are identified by their high-affinity binding to several carcinogenic or teratogenic environmental chemicals including polycyclic aromatic hydrocarbons found in cigarette smoke and smog, heterocyclic amines found in cooked foods, and halogenated hydrocarbons including dioxins and polychlorinated biphenyls. No endogenous ligand has been identified, but an unknown natural messenger with a role in cell differentiation and development is suspected.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)Enzyme Induction: An increase in the rate of synthesis of an enzyme due to the presence of an inducer which acts to derepress the gene responsible for enzyme synthesis.Neoplasms, Experimental: Experimentally induced new abnormal growth of TISSUES in animals to provide models for studying human neoplasms.Ethers, Cyclic: Compounds of the general formula R-O-R arranged in a ring or crown formation.Chlorodiphenyl (54% Chlorine)Anisoles: A group of compounds that are derivatives of methoxybenzene and contain the general formula R-C7H7O.Metabolic Detoxication, Drug: Reduction of pharmacologic activity or toxicity of a drug or other foreign substance by a living system, usually by enzymatic action. It includes those metabolic transformations that make the substance more soluble for faster renal excretion.Coke: A residue of coal, left after dry (destructive) distillation, used as a fuel.Cocarcinogenesis: The combination of two or more different factors in the production of cancer.Deoxyguanosine: A nucleoside consisting of the base guanine and the sugar deoxyribose.Soil Pollutants: Substances which pollute the soil. Use for soil pollutants in general or for which there is no specific heading.Environmental Pollutants: Substances or energies, for example heat or light, which when introduced into the air, water, or land threaten life or health of individuals or ECOSYSTEMS.Butylated Hydroxyanisole: Mixture of 2- and 3-tert-butyl-4-methoxyphenols that is used as an antioxidant in foods, cosmetics, and pharmaceuticals.Tetrachlorodibenzodioxin: A chemical by-product that results from burning or incinerating chlorinated industrial chemicals and other hydrocarbons. This compound is considered an environmental toxin, and may pose reproductive, as well as, other health risks for animals and humans.Kinetics: The rate dynamics in chemical or physical systems.Fluorenes: A family of diphenylenemethane derivatives.Chlorophyllides: Products of the hydrolysis of chlorophylls in which the phytic acid side chain has been removed and the carboxylic acids saponified.2-Acetylaminofluorene: A hepatic carcinogen whose mechanism of activation involves N-hydroxylation to the aryl hydroxamic acid followed by enzymatic sulfonation to sulfoxyfluorenylacetamide. It is used to study the carcinogenicity and mutagenicity of aromatic amines.9,10-Dimethyl-1,2-benzanthracene: 7,12-Dimethylbenzanthracene. Polycyclic aromatic hydrocarbon found in tobacco smoke that is a potent carcinogen.Phenols: Benzene derivatives that include one or more hydroxyl groups attached to the ring structure.Fluorescent Dyes: Agents that emit light after excitation by light. The wave length of the emitted light is usually longer than that of the incident light. Fluorochromes are substances that cause fluorescence in other substances, i.e., dyes used to mark or label other compounds with fluorescent tags.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.Fundulidae: Family of small, surface-dwelling fish that inhabit fresh and brackish waters, and coastal marine areas.Liver: A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.MaleimidesStructure-Activity Relationship: The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups.Salmonella typhimurium: A serotype of Salmonella enterica that is a frequent agent of Salmonella gastroenteritis in humans. It also causes PARATYPHOID FEVER.Water Pollutants, Chemical: Chemical compounds which pollute the water of rivers, streams, lakes, the sea, reservoirs, or other bodies of water.DNA Damage: Injuries to DNA that introduce deviations from its normal, intact structure and which may, if left unrepaired, result in a MUTATION or a block of DNA REPLICATION. These deviations may be caused by physical or chemical agents and occur by natural or unnatural, introduced circumstances. They include the introduction of illegitimate bases during replication or by deamination or other modification of bases; the loss of a base from the DNA backbone leaving an abasic site; single-strand breaks; double strand breaks; and intrastrand (PYRIMIDINE DIMERS) or interstrand crosslinking. Damage can often be repaired (DNA REPAIR). If the damage is extensive, it can induce APOPTOSIS.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)Petroleum: Naturally occurring complex liquid hydrocarbons which, after distillation, yield combustible fuels, petrochemicals, and lubricants.Cricetinae: A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.SmokeMycobacterium: A genus of gram-positive, aerobic bacteria. Most species are free-living in soil and water, but the major habitat for some is the diseased tissue of warm-blooded hosts.Phenobarbital: A barbituric acid derivative that acts as a nonselective central nervous system depressant. It potentiates GAMMA-AMINOBUTYRIC ACID action on GABA-A RECEPTORS, and modulates chloride currents through receptor channels. It also inhibits glutamate induced depolarizations.Lung: Either of the pair of organs occupying the cavity of the thorax that effect the aeration of the blood.Poly G: A group of guanine ribonucleotides in which the phosphate residues of each guanine ribonucleotide act as bridges in forming diester linkages between the ribose moieties.

Platelet high affinity low density lipoprotein binding and import of lipoprotein derived phospholipids. (1/624)

The binding of low density lipoprotein (LDL) to the platelet cell membrane could facilitate the transfer of phospholipids from LDL to the platelets. A polyclonal antibody against the platelet glycoproteins IIb/IIIa inhibited the high affinity binding of 125I-LDL by up to 80%. The transfer of pyrene (py)-labeled sphingomyelin (SM), phosphatidylcholine and phosphatidylethanolamine from LDL to the platelets was unaffected by the antibody. The lectin wheat germ agglutinin (WGA) reduced the binding of 125I-LDL to the platelets by approximately 80%. In contrast, the lectin stimulated the transfer of SM from LDL into the platelets by about three-fold. WGA also specifically augmented the transfer of py-SM between lipid vesicles and the platelets, the stimulation being abolished in the presence of N-acetylglucosamine. Dextran sulfate (DS) increased the specific binding of 125I-LDL to the platelets by up to 2.8-fold. On the other hand, the import of LDL-derived py-phospholipids was unaffected by DS. Together, the results indicate that the phospholipid transfer from LDL to the platelets is independent of the high affinity LDL binding to the platelets and is specifically stimulated by WGA. Thus, the interactions of platelets with LDL phospholipids differ markedly from those with the apoprotein components of the lipoproteins.  (+info)

Characterization of mannooligosaccharide caps in mycobacterial lipoarabinomannan by capillary electrophoresis/electrospray mass spectrometry. (2/624)

A new analytical approach based on capillary electrophoresis-electrospray mass spectrometry (CE/ESI-MS) has provided new insight into the characterization of mannooligosaccharide caps from lipoarabinomannans (LAMs), which are key molecules in the immunopathogenesis of tuberculosis. This analytical approach requires oligosaccharide labeling with the fluorophore 1-aminopyrene-3,6,8-trisulfonate (APTS) by reductive amination at the reducing termini. Optimization of the separation and ionization conditions, such as the choice of capillary electrophoresis (CE) electrolyte buffers, is presented and discussed. Anionic separation of the mono and oligosaccharide APTS derivatives was finally achieved with aqueous triethylammonium formate buffer. It was found that in contrast to the triethylammonium phosphate buffer, the triethylammonium formate buffer was appropriate for CE/ESI-MS coupling analysis of APTS-carbohydrate derivatives. In this case, negative ESI-mass spectra of APTS-carbohydrate adducts showed mainly (M-2H)2-pseudomolecular ions and some sequence fragment ions allowing their non-ambiguous structural characterization at the picomolar level. This analytical approach was successfully applied to more complex mixtures of carbohydrates released by mild acid hydrolysis of the lipoarabinomannans from Mycobacterium bovis BCG. The APTS-mannooligosaccharide cap adducts were separated by CE and their structural characterization achieved by CE/ESI-MS analyses. Mannooligosaccharide caps were routinely analyzed by capillary electrophoresis-laser induced fluorescence (CE-LIF) from 50 fmol of lipoarabinomannans with mannosyl capping (ManLAMs) but sensitivity was about 50 times lower using ESI-MS detection.  (+info)

HPLC/fluorescence determination of anti-BPDE-DNA adducts in mononuclear white blood cells from PAH-exposed humans. (3/624)

The aim of this study was to compare (+/-)-r-7,t-8-dihydroxy-t-9,10-oxy-7,8,9,10-tetrahydrobenzo[a]pyrene (anti-BPDE)-DNA adduct levels in groups of humans subjected to various levels of polycyclic aromatic hydrocarbon (PAH) (benzo[a]pyrene) exposure. An HPLC/fluorescence method was applied to detect specifically anti-BPDE-DNA adducts in mononuclear white blood cells [lymphocyte plus monocyte fraction (LMF)] from humans exposed to PAHs. A total of 130 subjects comprised the sample population: 26 psoriatic patients (3 days after clinical coal tar treatment of the skin), 15 coke oven workers, 19 chimney sweeps, 36 aluminium anode plant workers and 34 non-occupationally PAH-exposed subjects (controls). PAH exposure was assessed in each group by means of the urinary excretion of 1-pyrenol (mean group levels: 1.2, 0.7, 0.3, 65.0 and 0.1 micromol/mol creatinine in coke oven workers, chimney sweeps, aluminium plant anode workers, psoriatic patients and non-occupationally PAH-exposed subjects, respectively). HPLC/fluorescence analysis of BPDE-DNA adducts showed that the percentage of subjects with adduct levels exceeding the 95 percentile control subject value (8.9 adducts/10(8) nucleotides) was significantly high in coke oven workers (46.7%) and chimney sweeps (21.0%) (chi2 test, P < 0.01 and P < 0.05, respectively) but not in aluminium plant workers (11.1%) and psoriatic patients (0%). The increase in BPDE-DNA adduct levels in LMF (Ln values) was significantly related to chronic inhalatory and high PAH exposure (linear multiple regression analysis, F = 6.37, P < 0.01; t = 4.2, P < 0.001). Skin acute (or short-term) and high PAH exposure, charcoal-grilled meat consumption and smoking habit did not seem to influence BPDE-DNA adduct formation in LMF.  (+info)

Comparative metabolism of 1-, 2-, and 4-nitropyrene by human hepatic and pulmonary microsomes. (4/624)

Determining the capability of humans to metabolize the mononitropyrene (mono-NP) isomers 1-, 2-, and 4-NP and understanding which human cytochrome P450 (P450) enzymes are involved in their activation and/or detoxification is important in the assessment of individual susceptibility to these environmental carcinogens. We compared the ability of 15 human hepatic and 8 pulmonary microsomal samples to metabolize each of the three isomers. Human hepatic microsomes were competent in metabolizing all three isomers. Qualitatively similar metabolic patterns were observed, although at much lower levels, upon incubating mono-NP with pulmonary microsomes. Ring-oxidized metabolites (phenols and trans-dihydrodiols) were produced from all three isomers. However, the nitroreductive metabolism leading to the formation of aminopyrene was evident only with 4-NP. The role of specific P450 enzymes in the human hepatic microsomal metabolism of mono-NP was investigated by correlating the P450-dependent catalytic activities in each microsomal sample with the levels of individual metabolites formed by the same microsomes and by examining the effects of agents that can either inhibit or stimulate specific P450 enzymes in mono-NP metabolism. On the basis of these studies, we attribute most of the hepatic microsomal metabolism of 1- and 4-NP to P450 3A4, although a minor role for P450 1A2 cannot be ruled out. Specifically, P450 3A4 was responsible for the formation of 3-hydroxy-1nitropyrene from 1-NP and the formation of trans-9,10-dihydro-9,10dihydroxy-4-nitropyrene, 9(10)-hydroxy-4-nitropyrene, and 4-aminopyrene from 4-NP. None of the P450 enzymes examined (P450s 3A4, 1A2, 2E1, 2A6, 2D6, and 2C9) appeared to be involved in catalyzing the formation of trans-4,5-dihydro-4,5-dihydroxy-2-nitropyrene and 6-hydroxy-2-nitropyrene from 2-NP in human hepatic microsomes. These results, the first report on the comparative metabolism of mono-NP in humans, clearly demonstrate that the role of specific human P450 enzymes in catalyzing oxidative and reductive pathways of mono-NP is dependent upon the position of the nitro group.  (+info)

Genotoxic exposures of potroom workers. (5/624)

OBJECTIVES: Potroom workers in aluminum reduction plants have increased risks for bladder and lung cancer due to exposure from polycyclic aromatic hydrocarbons (PAH). In this study correlations between measures of the external, internal, and biological effective dose have been studied for PAH. METHODS: Venous blood samples were obtained from 98 male potroom workers and 55 unexposed male blue-collar workers, for the analysis of aromatic adducts to DNA (deoxyribonucleic acid) in lymphocytes, using the 32P-postlabeling technique. 1-Hydroxypyrene in urine was analyzed with high-pressure liquid chromatography. Personal sampling of both particulate and gas phase PAH was performed during a full workday for the potroom workers and for 5 referents. Individual PAH congeners were determined with liquid chromatographic-mass spectrometric and gas chromatographic-mass spectrometric techniques. RESULTS: The respiratory-zone airborne level of the sum of 22 particulate (median 13.2 micro/m3) and the 7 gas phase PAH-congeners (median 16.3 microg/m3) among the potroom workers was a hundred times higher than among the referents. The urinary concentration of 1-hydroxypyrene before work was 30 times higher for the potroom workers (median 3.43 micromol/mol creatinine) than for the referents. Most airborne PAH congeners correlated with the excretion of 1-hydroxypyrene in urine. The frequency of aromatic DNA adducts did not, however, differ between the potroom workers and the referents, and no correlation was found for 1-hydroxypyrene in urine. CONCLUSIONS: Despite an obvious occupational exposure to PAH, no increase in aromatic DNA adducts in lymphocytes was found among the potroom workers.  (+info)

Molecular mechanisms of peptide loading by the tumor rejection antigen/heat shock chaperone gp96 (GRP94). (6/624)

Complexes of gp96/GRP94 and peptides have been shown to elicit immunogenicity. We used fluorescence to understand peptide association with gp96. A pyrene-peptide conjugate was complexed with gp96 under a variety of conditions. At room temperature in low salt (20 mM NaCl), the peptide binds gp96 with a strong affinity (approximately 100-150 nM) and forms pyrene excimers, suggesting that the peptides were assembled as dimers. In high salt (2.2 M NaCl), although peptide binding was stronger (Ka approximately 55 nM) than in low salt, pyrene excimers were absent, implying that peptides were farther apart in the complex. Heat shock-activated peptide binding exhibited characteristics of both low salt and high salt modes of binding. Anisotropy and average lifetime of the bound pyrene suggested that peptides were probably located in a solvent-accessible hydrophobic binding pocket in low salt, whereas in high salt, the peptide may be buried in a less hydrophobic (more hydrophilic) environment. These results suggested that peptide-gp96 complexes were assembled in several different ways, depending on the assembly conditions. Resonance energy transfer between the intrinsic tryptophan(s) in gp96 and pyrene suggested that one or more tryptophan residues were within the critical Forster distance of 27-30 A from the pyrene in the bound peptide. It is proposed that peptides are assembled within higher order gp96 complexes (dimers, etc.) in a hydrophobic pocket and that there may be a conformational change in gp96 leading to an open configuration for peptide loading.  (+info)

Pathologic changes induced in respiratory tract mucosa by polycyclic hydrocarbons of differing carcinogenic activity. (7/624)

Seven aromatic polycyclic hydrocarbons (PCHs) were investigated for their toxic effects on respiratory mucosa: benzo(e)pyrene (BeP), pyrene, anthracene, benz(a)anthracene(BaA), dibenz(a,c)anthracene(DBacA), benzo (a)pyrene (BaP), and dimethylbenz(a)anthracene (DMBA). The compounds were chosen because they comprise a spectrum of PCHs ranging from noncarcinogens, to initiators, to weak and strong carcinogens. All of them except DMBA are environmentally relevant chemicals. The chemicals were tested over an 8-week period. Heterotopic tracheal transplants were continously exposed and the histopathologic effects induced by the various PCHs were periodically assessed semiquantitatively. All PCHs exhibited varying degrees of toxicity for respiratory epithelium and submucosa. BeP clearly showed the least toxicity followed by pyrene and anthracene. BaA and DBacA caused marked epithelial and submucosal changes. In addition to epithelial hyperplasia, undifferentiated epithelium and squamous metaplasia developed. Marked mononuclear infiltration occurred in the subepithelial connective tissue. With BaP the epithelial and submucosal changes were similar but were much stronger. DMBA was the most toxic substance, causing epithelial necrosis followed by generalized keratinizing squamous metaplasia; the subepithelial changes consisted of an early acellular exudate and, later (at 8 weeks), marked condensation and hyalinization of the lamina propria. The toxic response pattern of the tracheal mucosa to carcinogenic agents was characterized by the chronicity of epithelial and connective tissue damage, as opposed to the short-lived hyperplastic and inflammatory response elicited by the noncarcinogens and weak initiators.  (+info)

2'-Pyrene modified oligonucleotide provides a highly sensitive fluorescent probe of RNA. (8/624)

Oligonucleotide 9mers containing 2'-O-(1-pyrenylmethyl)uridine [U(pyr)] at the center position were synthesized by using a protected U(pyr) phosphoramidite. The UV melting behaviors indicate that the pyrene-modified oligonucleotides can bind to both their complementary DNA and RNA in aqueous solution. When compared with the unmodified oligonucleotides, the pyrene-modified oligonucleotides showed higher affinity for DNA while exhibiting lower affinity for RNA. The pyrene-modified oligonucleotides in diluted solution exhibited fluorescence typical of pyrene monomer emission [lambdamax 378 (band I) and 391 nm (band III)]. When these oligomers bound to DNA, the fluorescence intensity ratio of band III/band I was increased. With this fluorescence change, a new broad emission (lambdamax 450 nm) due to exciplex between the pyrene and an adjacent nucleobase appeared. In contrast, addition of RNA to the pyrene oligonucleotides resulted in enhancement of the pyrene monomer emission with decrease in the fluorescence band ratio. The extent of the emission enhancement was found to be highly dependent on the nucleobase adjacent to the U(pyr) in the pyrene oligomers. The pyrene oligonucleotide containing dC at the 3'-site of the modification showed remarkable increase (approximately 250 times) in fluorescence (375 nm) upon binding to complementary RNA. The present findings would open the way to the design of a highly sensitive fluorescent probe of RNA.  (+info)

  • Pyrene and its derivatives are used commercially to make dyes and dye precursors, for example pyranine and naphthalene-1,4,5,8-tetracarboxylic acid. (
  • It is shown by 1 H NMR that this ratiometric change is due to the conformational changes of the pyrenes during the chelation of Mg 2+ by the amide functions to form a 1:1 complex. (
  • It is shown by 1H NMR that this ratiometric change is due to the conformational changes of the pyrenes during the chelation of Mg2+ by the amide functions to form a 1:1 complex. (
  • Most studies reviewed here measured tetraols released from DNA or protein by hydrolysis of adducts derived from (7R,8S)-dihydroxy-(9S,10R)-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (BPDE), a major ultimate carcinogen of BaP. (
  • DeBruyn, Jennifer M., "Distribution and dynamics of pyrene-degrading Mycobacteria in freshwater sediments contaminated with polycyclic aromatic hydrocarbons. (
  • To investigate the specificity of biological monitoring variables (excretion of phenanthrene and pyrene metabolites in urine) and the usefulness of some biomarkers of effect (alkaline filter elution, {sup}32{end}P postlabeling assay, measurement of sister chromatid exchange)in workers exposed to polycyclic aromatic hydrocarbons (PAHs). (
  • Pyrene forms during incomplete combustion of organic compounds. (
  • The highest mineralization of [14C] pyrene was detected in straw cultures of T. versicolor (34.1%), which suggested that mineralization of both compounds by fungi may be independent of the number of aromatic rings. (
  • A new class of dual fluorescent chemosensors for nitroaromatic compounds (NACs) based on phosphonated pyrene derivatives is reported, showing high selectivity towards trinitrotoluene (TNT). (
  • This compound belongs to the class of organic compounds known as pyrenes. (
  • These are compounds containing a pyrene moiety, which consists four fused benzene rings, resulting in a flat aromatic system. (
  • Pyrene used as a model PAH due to its specific volatility and miscibility characteristics, relatively soluble yet hydrophobic to explore the potential of sepiolite (Turkish origin) to sorb hydrophobic organic compounds from aqueous solution. (
  • However, its intracrystalline interactions with pyrene were more favorable than the surface Si-OH groups which could react directly with pyrene to form compounds with true covalent bonds (chemical interactions) between sepiolite and pyrene. (
  • These compounds exhibit unusual photophysical properties such as emission in the green region of the electromagnetic spectrum in hexane, whereas all other previously reported pyrene derivatives substituted at the 2,7-positions show blue luminescence. (
  • More than 20% of the carbon in the universe may be associated with PAHs, including pyrene. (
  • These PAHs are naphthalene, fluorene, phenanthrene, and pyrene , all present in high concentrations in the complex Superfund-derived PAH mixture. (
  • This work demonstrates the prevalence of pyrene-degrading organisms in contaminated sediments and implicates an integral role in natural attenuation of HMW PAHs. (
  • A. S. Oliveira, L. F. Vieira Ferreira, J. P. Da Silva, and J. C. Moreira, "Surface photochemistry: Photodegradation study of pyrene adsorbed onto microcrystalline cellulose and silica," International Journal of Photoenergy , vol. 6, no. 4, pp. 205-213, 2004. (
  • The document reports on such a study of pyrene and in addition, compares the pressure-enhanced electronic relaxation for the monomeric and excimeric forms of pyrene. (
  • Effects on 7,8-dihydroxy-9, 10-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (BPDE)-DNA adduct formation were evaluated in DNA from mice treated with isothiocyanates and B[a]P, and killed 2-120h later. (
  • A pyrene-functionalized polymer was patterned via electron beam lithography onto a silicon wafer and shown to selectively bind with carbon nanotubes . (
  • This review exposes the current poor understanding of the internal segmental chain dynamics of dendrimers in solution probed by monitoring the process of excimer formation between pyrene labels covalently attached to the chain ends of dendrimers. (
  • The review begins by covering the bases of fluorescence and the kinetics of pyrene excimer formation before describing a procedure based on the Model Free (MF) analysis that is used to analyze quantitatively the fluorescence decays acquired for dendrimers, the ends of which have been fully and covalently labeled with pyrene. (
  • AKL99 ) has been modified to contain covalently linked pyrene at the cysteine 374 residue. (
  • In recent years, pyrene‐based porous materials have been widely used in various fields, such as photo‐catalysis, photoelectric devices, chemical sensing, gas storage and separation, and degradation of nerve agent simulants due to their excellent rigidity and photophysical properties. (
  • Influence of contact time on extractability and degradation of pyrene in sons. (
  • Fourier transform infrared spectroscopy (FT-IR), ultraviolet and visible spectroscopy (UV-Vis), and fluorescence spectroscopy were used to characterize the nanocomposites of pyrene clicked MWCNTs. (
  • The nonsterile pasture soil was the only incubation to show significant loss of [C-b>pyrene -associated activity over the 24-week incubation. (
  • Significant decreases in methanol:water and n-butanol extractability were observed with increasing soil-pyrene contact time. (
  • After 8 weeks soil-pyrene contact time, there was a significant increase in the rate and extent of sequestration of pyrene in the biologically active soils. (
  • This indicated that the aging of pyrene was initially a physical process, with active microbial communities increasing the rate and extent of residue formation after 8 weeks soil-pyrene contact time. (
  • The humin fraction of the soil organic matter contained the majority of the 14C-pyrene associated activity which was not extractable using the scheme of sequential solvents. (
  • Saponification of the soil humin resulted in the release of similar amounts of 14C-pyrene associated activity from sterile and non-sterile soils. (
  • In this study, temporal changes in the extractability of 14C-pyrene, at native concentrations, were followed in two soils with differing organic matter contents, under sterile and non-sterile conditions over 24 weeks by a sequential solvent extraction scheme. (
  • Pyrene punctata, common name : the telescoped dove shell, is a species of sea snail, a marine gastropod mollusk in the family Columbellidae, the dove snails. (
  • Cyclopenta[c,d]pyrene (CAS 27208-37-3) Market Research Report 2017 contents were worked out and placed on the website in December, 2017. (
  • Please note that Cyclopenta[c,d]pyrene (CAS 27208-37-3) Market Research Report 2017 is a half ready publication and contents are subject to change. (
  • To study the possible reduction by eugenol of the mutagenicity and genotoxicity of benzoja]pyrene (B[a]P) in vivo, the X-lacZ-transgenic mouse strain 40.6 (Muta(TM)Mouse) was used. (
  • The review points out that the MF analysis of the fluorescence decays acquired with pyrene-labeled dendrimers enables one to account for the presence of unattached pyrene and to retrieve information about the internal segmental dynamics of the dendrimer. (
  • In this study, temporal changes in extractability of [C-b>pyrene were followed in two soils with differing organic matter contents under sterile and nonsterile conditions over 24 weeks. (
  • Temporal changes in the availability of pyrene in two soils under sterile and non-sterile conditions. (
  • Winkelmann J. (2018) Diffusion coefficient of pyrene in octane at infinite dilution. (
  • The results of these studies indicate the pyrene-degrading Mycobacteria have broad, cosmopolitan distribution in contaminated sediments and suspended particles. (
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