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Sample records for carcinogenic agents uv

  1. Environmental carcinogenic agents and cancer prevention. Risk assessment and management

    International Nuclear Information System (INIS)

    Many agents in our environment have been established as being carcinogenic, and in most cases, the carcinogenic properties of these agents were identified because of high-dose occupational or accidental exposure. Risk characterization, taking into account the dose-response relationship, and exposure assessment are essential for risk assessment and subsequent cancer prevention. Based on scientific risk assessment, risk management should be conducted practically by considering the economic, social, political, and other technical issues and by balancing the risks and benefits. Asbestos and environmental tobacco smoke are typical examples of established carcinogenic agents in the general environment, contributing to low-dose exposure. Further epidemiological studies are required to investigate the carcinogenicity of low-dose exposure to known carcinogenic agents such as arsenic and cadmium through dietary intake, radiation via medical and natural exposure, and air pollution due to diesel exhaust. In contrast, occupational chemical exposure to 1,2-dichloropropane and/or dichloromethane, whose carcinogenicity had not been established, was suggested to cause cholangiocarcinoma among workers involved in offset color proof-printing only after a rare situation of high-dose exposure was unveiled. Continuous monitoring of unusual cancer occurrences in target populations such as workers in occupational and regional settings as well as exposure reduction to suspected carcinogenic agents to levels as low as reasonably achievable is essential for reducing the risk of cancer due to environmental carcinogens. (author)

  2. Carcinogenic risks associated with radiation pollution. [UV radiation, sunlight

    Energy Technology Data Exchange (ETDEWEB)

    Latarjet, R.

    1976-01-01

    The cancerogenic pollution by non-ionizing radiations is limited to the case of solar ultraviolet, whose activity at ground level may be increased as a consequence of the stratospheric depletion of ozone, produced by certain chemical pollutants: nitrogen oxides from supersonic aircrafts, freon. As regards ionizing radiations, the discussion is focused on the fundamental problem of the threshold, and on the means by which one may obtain some quantitative data related to carcinogenesis by small radiation doses in man. A new concept, that of a practical threshold, is proposed. A theory which links radiocancerogenesis, as well as chemical cancerogenesis, to errors produced in the repair of lesions in the DNA is discussed. The rads-equivalent project for chemical mutagens and carcinogens is described.

  3. Strategies of reducing the carcinogenic risk of cytostatic agents on the basis of bioassay evaluation.

    Science.gov (United States)

    Berger, M R

    1991-01-01

    This article described strategies that can be used to reduce the carcinogenic risk of cytostatic chemotherapy and summarizes our recent experimental results. Reduction of neoplasms caused by the carcinogenic potency inherent in cytostatic agents can be obtained. (A) by chemical modifications such as: (1) exchanging a chlorine atom in N, N'-bis-(2-chloroethyl)-N-nitrosourea (BCNU) in the chloroethyl group at N'-position for a hydroxyl group to form the less carcinogenic analog N-(2-chloroethyl)-N'-(2-hydroxyethyl)-N-nitrosourea (HECNU); (2) linking chlorambucil to the steroid prednisolone to obtain a conjugate (prednimustine) with distinctly lower carcinogenic potential than chlorambucil; (3) progressive ring halogenation of phenyl-triazenes to generate agents with decreased long-term toxic risk; (B) by replacing cyclophosphamide within the carcinogenic drug combination of cyclophosphamide, methotrexate and 5-fluorouracil (CMF) by vincristine to form the combination VMF which has no detectable carcinogenic potential; (C) by coadministration of cyclophosphamide and mesna to achieve a dose-related reduction of cyclophosphamide-induced urinary bladder carcinomas; (D) by administration of dinaline, a compound which reduces the spontaneous incidence of malignant tumors in rats. These examples demonstrate that the carcinogenic risk of single agents and drug combinations used for antineoplastic chemotherapy has successfully been reduced, as assessed in long-term bioassays. Such strategies should be considered in the treatment of patients with long life expectancy following cytotoxic chemotherapy.

  4. Screening tests for determination of cytotoxic agent, mutagens and carcinogens

    Energy Technology Data Exchange (ETDEWEB)

    Spiegelberg, T.; Koerdel, W.; Goertz, T.; Thriemer, A.

    1983-01-01

    It is supposed that chemical substances are the primary factors responsible for the development of tumors and genetic damages. From this results the urgend demand to examine at least the frequently applied and suspicious substances on possibly health-affecting effects. The performance of these examinations with experimental animals requires a lot of time and financial support and has increasingly been criticised in public with regard to protection of animals. Experience gained in the U.S.A. revealed that the carcinogenicity test of one single substance performed with animal experiments takes approximately 3 years and costs about 300,000 Dollars. Therefore the application of cell cultures for such examinations and tests has been postulated and discussed for several years. Cell cultures require only little space and generally the observed effects develop after only a short time. Objectification and statistical assessment (due to high cell amounts per test) can be performed without any problems.

  5. Rodent carcinogenicity with the thiazolidinedione antidiabetic agent troglitazone.

    Science.gov (United States)

    Herman, J R; Dethloff, L A; McGuire, E J; Parker, R F; Walsh, K M; Gough, A W; Masuda, H; de la Iglesia, F A

    2002-07-01

    Carcinogenic potential of the thiazolidinedione antidiabetic troglitazone was assessed in 104-week studies in mice and rats. Mice were given 50, 400, or 800 mg/kg, male rats 100, 400, or 800 mg/kg, and female rats 25, 50, or 200 mg/kg. Vehicle and placebo controls were included. Survival was significantly decreased in both sexes of both species at high doses, but was adequate for valid evaluation of carcinogenicity. Hypertrophy and hyperplasia of brown adipose tissue was observed in both species at all doses, and fatty change and hypocellularity of bone marrow was noted in mice at all doses and in female rats at 50 and 200 mg/kg. Hepatocellular vacuolation was observed in mice at 400 and 800 mg/kg, and centrilobular hepatocellular hypertrophy occurred in rats at > or = 200 mg/kg. Ventricular dilatation, myocardial fibrosis, and atrial myocyte karyomegaly in male rats at 400 and 800 mg/kg and female rats at all doses were morphologically similar to spontaneous lesions, but incidence and severity were increased compared with controls. In mice, the incidence of hemangiosarcoma was increased in females at 400 mg/kg and in both sexes at 800 mg/kg. The incidence of hepatocellular carcinoma was increased in female mice at 800 mg/kg. Troglitazone exposure [AUC((0-24))] at the lowest dose associated with increased tumor incidence in mice was 16 times human therapeutic exposure at 400 mg daily. No tumors of any type were increased in rats at exposures up to 47 times therapeutic exposure.

  6. Chemical carcinogenic and mutagenic agents in the workplace, Poland, 2008–2010

    Directory of Open Access Journals (Sweden)

    Katarzyna Konieczko

    2013-04-01

    Full Text Available Background: The aim of this paper is to present a concise but comprehensive information on the occurrence of carcinogenic or mutagenic agents in Polish enterprises and the number of workers exposed to those agents reported to the central register by employers. Objectives and responsibilities of the register, as well as the range and methods of data gathering are discussed. Material and Methods: Data concerning carcinogenic or mutagenic chemical substances and technological processes reported to central register in 2008-2010 were analyzed. Results: In 2008-2010 more than 300 carcinogenic or mutagenic chemical substances were reported to the register. Approximately 2500 plants reported above 150 000 per-person-exposures annually. Among all technological processes regarded as occupational carcinogens, hardwood dusts exposure (about 660 companies; 11 000-13 000 exposed workers each year and exposure to polycyclic aromatic hydrocarbons (PAHs present in coal products (117-125 plantsl 3000 exposed per year were reported. Conclusions: The most widespread carcinogenic/mutagenic substances were: benzene, chromium(VI compounds: potassium dichromate and chromate, chromium(VI trioxide and other chromium compounds, ethylene oxide, asbestos, benzo[a]pyrene and gasoline. The highest number of men was exposed to particular PAHs and benzene , and the majority of women was exposed to benzene, potassium dichromate and chromate, acrylamide, ethylene oxide and gasoline. The lack of clear-cut definitione of occupational exposure to carcinogen creates a problem faced by employers in defining the accurate number of exposed workers. Med Pr 2013;64(2:181–192

  7. Abnormal regulation of DNA replication and increased lethality in ataxia telangiectasia cells exposed to carcinogenic agents

    Energy Technology Data Exchange (ETDEWEB)

    Jaspers, N.G.; de Wit, J.; Regulski, M.R.; Bootsma, D.

    1982-01-01

    The effect of different carcinogenic agents on the rate of semiconservative DNA replication in normal and ataxia telangiectasis (AT) cells was investigated. The rate of DNA synthesis in all AT cell strains tested was depressed to a significantly lesser extent than in normal cells after exposure to X-rays under oxia or hypoxia or to bleomycin, agents to which AT cells are hypersensitive. In contrast, inhibition of DNA replication in normal human and AT cells was similar after treatment with some DNA-methylating agents or mitomycin C. Colony-forming ability of AT cells treated with these agents was not different from normal cells. Treatment with 4-nitroquinoline 1-oxide elicited a variable response in both AT and normal cell strains. In some strains, including those shown to be hypersensitive to the drug by other workers, the inhibition of DNA synthesis was more pronounced than in other cell strains, but no significant difference between AT and normal cells could be detected. The rejoining of DNA strand breaks induced by X-rays, measured by DNA elution techniques, occurred within l2 hr after treatment and could not be correlated with the difference in DNA synthesis inhibition in AT and normal cells. After low doses of X-rays, AT cells rejoined single-strand breaks slightly more slowly than did normal cells. The rate of DNA replication in X-irradiation AT and normal cells was not affected by nicotinamide, an inhibitor of poly(adenosine diphosphate ribose) synthesis. These data indicate that the diminished inhibition of DNA replication in carcinogen-treated AT cells (a) is a general characteristic of all AT cell strains, (b) correlates with AT cellular hypersensitivity, (c) is not directly caused by the bulk of the DNA strand breaks produced by carcinogenic agents, and (d) is not based on differences in the induction of poly(adenosine diphosphate ribose) synthesis between X-irradiated AT and normal cells.

  8. Occupational UV exposure of environmental agents in Valencia, Spain

    OpenAIRE

    Serrano Jareño, María Antonia; Cañada, Javier; Moreno Esteve, Juan Carlos; Gurrea Ysasi, Gonzalo

    2014-01-01

    The aim of this paper is to measure UV exposure of environmental agents in their occupational schedules in summer in Valencia province (Spain) using VioSpor personal dosimeters attached to several parts of their bodies. Due to its geographical situation, Valencia receives large UVR doses throughout the year, and the work of environmental agents is directly related to the protection, care, and custody of natural, often in mountainous areas. Comparison with the occupational UV exposure limit sh...

  9. Matrix of occupational exposures to carcinogenic agents and pesticides in Costa Rica

    International Nuclear Information System (INIS)

    The European data system CAREX converts national numbers of workers in 55 sectors and estimated proportions of workers exposed to carcinogenic agents into numbers of workers exposed to each agent. CAREX is applied and modified in Costa Rica (TICAREX) for the first time outside Europe. 27 carcinogenic agents and 7 groups of pesticides were included. Numbers of exposed were estimated separately for men and women. The most frequent agents in the 1.3 million labor force of Costa Rica were solar radiation (333,000 workers); diesel engine emissions (278,000); paraquat and diquat (175,000); environmental tobacco smoke (71,000); chromium (VI) compounds (55,000); benzene (52,000); mancozeb, maneb and zineb (49,000); chlorothalonil (38,000); wood dust (32,000); silica dust (27,000); benomyl (19,000); lead and its inorganic compounds (19,000); tetrachloroethylene (18,000); and polycyclic aromatic hydrocarbons (17,000). Owing to the different occupational distribution between the genders, formaldehyde, radon and methylene chloride were more frequent than pesticides, chromium (VI), wood dust, and silica dust in women. Agriculture, construction, personal and domestic services, land and water transport and allied services, pottery and similar industries, manufacture of wood products, mining, forestry, fishing, manufacture of electric products, and bars and restaurants were sectors with frequent exposures. Substantial reduction of occupational and environmental exposures to these agents would improve considerably public and occupational health. Reduction of occupational exposures is usually also followed by improvement of environmental quality. Monitoring of exposures and health of workers and the general public is essential in the control of environmental contamination and human exposures. This report presents details of the exposures matrix, which is the basis of TICAREX. (author)

  10. Detection and impact on cancer causation of persons exhibiting abnormal susceptibility to carcinogenic agents

    International Nuclear Information System (INIS)

    The so-called 'late biological effects', like cancer and genetic consequences and cytotoxic effects (cell killing, at higher doses), were once thought to be an inevitable consequence of a given level of exposure, whether to background radiation, to chemicals in our biosphere, or form spontaneous damage, the 'wear and tear' of living. The measurement of exposure, which results in living organisms in the formation of a related amount of DNA damage, became a surrogate for the end-effects that constitute risk. This may not be entirely appropriate. The concept of 'equal exposure -- equal risk' assumes a homogeneous response of individuals. However, there are subgroups within the human population of persons whose cultured cells exhibit abnormal sensitivity to specific carcinogenic agents and who may be at increased risk of cancer induced by these of similar agents. Modern molecular biology has shown that the majority of the damage in DNA is repaired by enzymatic DNA repair processes that restitute or ameliorate the lesions and restore normal DNA structure and function. In this view, it is not the initial damage that is of consequence but rather the residual damage left after the repair processes have acted. Since the vast majority of the initial DNA damage undergoes repair normally, variation in the efficiency of these processes in different persons may affect the actual risk of exposure. The human side of the cancer causation formula, that is, considerable importance. To understand how human DNA repair processes function, our laboratories at Chalk River have studied 'mutant' human cell strains in tissue culture. Generally, these DNA repair-defective cell strains are derived from individual donors with heritable disorders that are associated with carcinogen-hypersensitivity and cancer-proneness. Such studies, together with related epidemiological research, have highlighted the importance of this new 'human' factor in carcinogenesis

  11. Exposure of Finnish population to solar UV radiation and consequent carcinogenic effects

    Energy Technology Data Exchange (ETDEWEB)

    Huurto, L.; Jansen, C. [Turku Univ. Hospital, Turku (Finland); Jokela, K. [Finnish Centre for Radiation and Nuclear Safety, Helsinki (Finland)

    1996-12-31

    Depletion of stratospheric ozone increases irradiance of terrestrial ultraviolet (UV) radiation at short wavelengths, which may be harmful to the human health. To understand quantitatively the risks caused by increasing UV radiation to the Finnish population, the actual UV exposure of the population has to be assessed. It was shown that the snow reflection increases the UV exposure to the face and eyes particularly in the northern Finland. In 1993 exceptionally low ozone levels persisted up to the end of May, which resulted in a theoretical increase in the annual UV dose ranging from 8 % to 13 % in Finland. The maximal increase in the measured erythemally effective dose rate was 34 % on 23 April, when compared with the theoretical normal value. During this study exposure models have been developed. The models have been combined them with Green`s radiation transfer model to estimate annual facial UV doses received by different groups of Finnish population. Also, an updated estimate for increase in skin cancer incidence due to the ozone depletion is presented. It is estimated that the maximal increase in UV doses caused by the depletion of the stratospheric ozone will be 12 % in the first years of the next century in Finland. This may result in increase in skin carcinomas by 20-30 % if the people do not improve their protection against solar UV radiation. At the moment the annual facial UV dose of the Finnish indoor worker varies from 3 % to 6 % of the annual ambient dose. In the worst case an outdoor worker may receive even 16% of the annual ambient dose. However, the doses received by indoor workers during vacation to an untanned skin may be more harmful due to the increased risk of malignant melanoma.

  12. Immunological detection and quantification of DNA components structurally modified by alkylating carcinogens, mutagens and chemotherapeutic agents

    International Nuclear Information System (INIS)

    The detection and quantification of defined reaction products of chemical mutagens and carcinogens (and of many cancer chemotherapeutic agents) with DNA require highly sensitive analytical techniques. The exceptional capability of immunoglobulins to recognize subtle alterations of molecular structure (especially when monoclonal antibodies are used to maximize specificity), outstanding sensitivity of immunoanalysis by high-affinity antibodies, and the fact that radioactively-labelled agents are not required suggest the utility of a radioimmunoassay to recognize and quantitate alkylated DNA products. We have recently developed a set of high-affinity monoclonal antibodies (secreted by mouse x mouse as well as by rat x rat hybridomas; antibody affinity constants, 109 to > 1010 lmol) specifically directed against several DNA alkylation products with possible relevance in relation to both mutagenesis and malignant transformation of mammalian cells. These alkylation products include 06-N-butyldeoxyguanosine, and 04-ethyldeoxythymidine. When used in a radioimmunassay, an antibody specific for 06-ethyldeoxyguanosine, for example, will detect this product at an 06-ethyldeoxyguanosine/deoxyguanosine molar ratio of approx. 3 x 10-7 in a hydrolysate of 100 ug of DNA. The limit of detection can be lowered further if the respective alkyldeoxynucleosides are separated by HPLC from the DNA hydrolysate prior to the RIA. The anti-alkyldeoxynucleoside monoclonal antibodies can also be used to visualize, by immunostaining and fluorescence microscopy combined with electronic image intensification, specific alkylation products in the nuclear DNA of individual cells, and to localize structurally modified bases in double-stranded DNA molecules by transmission electron microscopy

  13. Fire fighting trainers' exposure to carcinogenic agents in smoke diving simulators.

    Science.gov (United States)

    Laitinen, Juha; Mäkelä, Mauri; Mikkola, Jouni; Huttu, Ismo

    2010-01-15

    It is well known that fire fighters are potentially exposed to various carcinogenic agents at a fire scene. An almost unheeded issue, however, is fire fighters' exposure to carcinogenic agents in smoke diving simulators. Biomonitoring (urinary muconic acid, 1-naphthol and 1-pyrenol), dermal (polycyclic aromatic hydrocarbons) and occupational hygiene measurements (cyanides, hydrogen cyanide, polycyclic aromatic hydrocarbons, volatile organic compounds and formaldehyde) were used to determine how the burning material, the type of simulator and protective clothing used affect fire fighting trainers' exposure. The highest excretion of 1-pyrenol (sampled 6h after end of exposure, in average 4.3-9.2nmol/L) and emissions of benzene (1.0-2.5mg/m(3)) and hydrogen cyanide (0.2-0.9mg/m(3)) were measured during the burning of conifer plywood and chipboard, and the lowest when pure pine and spruce wood (1.5nmol/L, 0.6mg/m(3), and 0.05mg/m(3)) was burned. However the safest burning material seemed to be propane (1.0nmol/L, 0.2mg/m(3), and not measured). The type of simulator used affected trainers' exposure very clearly. The highest dermal whole body exposures to polycyclic aromatic hydrocarbons were measured in the fire house simulator (in average 1200ng/cm(2)). Clearly lower exposure levels were measured in container training sessions (760ng/cm(2)), where the average dermal exposure level was 35% lower than in the fire house. The exposure levels (30ng/cm(2)) in the gas simulator in turn, were only 4% of the levels in container training sessions. The amount of polycyclic aromatic hydrocarbons decreased by 80% on trainers' hands when they used under gloves (in average 8.7ng/cm(2)) compared to those (48.4ng/cm(2)) who did not. There was not difference in protection efficiency against polycyclic aromatic hydrocarbons between tested fire suits (Brage and Bristol). PMID:19576276

  14. Sensitivity to DNA-damaging agents and mutation induction by UV light in UV-sensitive CHO cells

    International Nuclear Information System (INIS)

    Three UV-sensitive (UVs) mutants isolated from a CHO cell line were analyzed for survival after exposure to H2O2, EMS, MMC, CCNU, X-rays and for mutation induction after UV-irradiation. The UVs mutants showed normal sensitivities to EMS and H2O2, whereas they were hypersensitive to the bifunctional alkylating agents MMC and CCNU and to hypoxic X-irradiation. Compared to parental cells, one of the UV-sensitive clones showed approximately 3- and 7-fold enhancement in the mutagenic response per unit UV dose for 6-thioguanine and ouabain resistance, respectively. (Auth.)

  15. An investigation of carcinogenic agents at the Mississippi Sandhill Crane National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report summarizes a study with the following results: 1. Three of the metals reported as carcinogens, arsenic, chromium, and nickel, were found within the...

  16. The Carcinogenic Agent Azoxymethane (AOM) Enhances Early Inflammation-induced Colon Crypt Pathology

    DEFF Research Database (Denmark)

    Venning, Freja Albjerg; Claesson, Mogens Helweg; Kissow, Hannelouise

    2013-01-01

    Severe combined immunodeficiency (SCID) mice transplanted with CD4+ T cells depleted of CD25+ regulatory T cells develop colitis within 2-3 weeks after the T cell transfer. In the present study we studied the effect of the carcinogen azoxymethane (AOM) on the colon crypt pathology of normal SCID...... mice and SCID mice with transfer colitis. AOM by itself did result in neither weight loss nor inflammation although treatment affected crypt widths and numbers. Although AOM together with T cell transfer did not increase the level of gut inflammation including COX-2 expression, AOM increased crypt...

  17. Ferns and lycopods--a potential treasury of anticancer agents but also a carcinogenic hazard.

    Science.gov (United States)

    Tomšík, Pavel

    2014-06-01

    Many species of seedless vascular plants-ferns and lycopods-have been used as food and folk medicine since ancient times. Some of them have become the focus of intensive research concerning their anticancer properties. Studies on the anticancer effect of crude extracts are being increasingly replaced by bioactivity-guided fractionation, as well as detailed assessment of the mechanism of action. Numerous compounds-especially flavonoids such as amentoflavone and protoapigenone, and also simpler phenolic compounds, steroids, alkaloids and terpenoids-were isolated and found to be cytotoxic, particularly pro-apoptotic, or to induce cell cycle arrest in cancer cell lines in vitro. In in vivo experiments, some fern-derived compounds inhibited tumour growth with little toxicity. On the other hand, many ferns-not only the well-known Bracken (Pteridium)-may pose a significant hazard to human health due to the fact that they contain carcinogenic sesquiterpenoids and their analogues. The objective of this review is to summarise the recent state of research on the anticancer properties of ferns and lycopods, with a focus on their characteristic bioactive constituents. The carcinogenic hazard posed by ferns is also mentioned. PMID:24123573

  18. Ferns and lycopods--a potential treasury of anticancer agents but also a carcinogenic hazard.

    Science.gov (United States)

    Tomšík, Pavel

    2014-06-01

    Many species of seedless vascular plants-ferns and lycopods-have been used as food and folk medicine since ancient times. Some of them have become the focus of intensive research concerning their anticancer properties. Studies on the anticancer effect of crude extracts are being increasingly replaced by bioactivity-guided fractionation, as well as detailed assessment of the mechanism of action. Numerous compounds-especially flavonoids such as amentoflavone and protoapigenone, and also simpler phenolic compounds, steroids, alkaloids and terpenoids-were isolated and found to be cytotoxic, particularly pro-apoptotic, or to induce cell cycle arrest in cancer cell lines in vitro. In in vivo experiments, some fern-derived compounds inhibited tumour growth with little toxicity. On the other hand, many ferns-not only the well-known Bracken (Pteridium)-may pose a significant hazard to human health due to the fact that they contain carcinogenic sesquiterpenoids and their analogues. The objective of this review is to summarise the recent state of research on the anticancer properties of ferns and lycopods, with a focus on their characteristic bioactive constituents. The carcinogenic hazard posed by ferns is also mentioned.

  19. Carcinogenicity study of the emulsifier TOSOM and the release agent TOS in Wistar rats

    DEFF Research Database (Denmark)

    Meyer, Otto A.; KRISTIANSEN, E.; GRY, J.;

    1993-01-01

    Groups of 60 Wistar rats of each sex were fed diets containing 3, 6 or 12% of the margarine emulsifier TOSOM (thermally oxidized soybean oil interacted with mono- and diglycerides of fatty acids) for 2.5 yr. In addition, three groups of 60 rats of each sex were fed two products of the release agent...... TOS (thermally oxidized soybean oil) in dietary levels of 1.2% TOS(G) (TOS from Grindsted Product A/S, Denmark) and 0.3 and 1.2% TOS(N) (TOS from Nexus Aps, Denmark), respectively for 2.5 yr. 120 rats of each sex fed a diet containing mono- and diglycerides served as controls. The diets given to all...... groups were isocaloric. Clinical appearance, food consumption, body weight and weight gain, survival, haematology, and clinical chemistry parameters were examined. Gross and histopathological examinations, including neoplastic and non-neoplastic lesions, were performed on all groups. Time to occurrence...

  20. /sup 32/P-Postlabeling test for covalent DNA binding of chemicals in vivo: Application to a variety of aromatic carcinogens and methylating agents

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, M.V.; Gupta, R.C.; Randerath, E.; Randerath, K.

    1984-02-01

    Carcinogen--DNA adducts were detected and determined by /sup 32/P-postlabeling assay after exposure of mouse or rat tissues in vivo to a total of 28 compounds comprising 7 arylamines and derivatives, 3 azo compounds, 2 nitroaromatics, 12 polycyclic aromatic hydrocarbons, and 4 methylating agents. DNA was isolated from mouse skin, mouse liver, and rat liver after treatment with the individual carcinogens, then digested enzymatically to deoxyribonucleoside 3'-monophosphates, which were converted to 5'-/sup 32/P-labeled deoxyribonucleoside 3',5'-bisphosphates by T4 polynucleotide kinase-catalyzed (/sup 32/P)phosphate transfer from (gamma-/sup 32/P)ATP. The nucleotides were resolved by anion-exchange t.l.c. on polyethyleneimine-cellulose and detected by autoradiography. The determination of low levels of DNA binding of the aromatic carcinogens entailed the removal of normal nucleotides prior to the resolution of adduct nucleotides. For this purpose, an alternative procedure employing reversed-phase t.l.c. was devised which offered advantages for the detection of quantitatively minor adducts. The procedures described enabled the detection of 1 aromatic DNA adduct in approximately 10(/sup 8/) normal nucleotides, while the limit of detection of methylated adducts was 1 adduct in approximately 6 X 10(/sup 5/) nucleotides. The results show that a great number of carcinogen-DNA adducts of diverse structure are substrates for /sup 32/P-labeling by polynucleotide kinase-catalyzed phosphorylation. Because covalent DNA adduct formation in vivo appears to be an essential property of the majority of chemical carcinogens, /sup 32/P-postlabeling analysis of carcinogen--DNA adducts in mammalian tissues may serve as a test for the screening of chemicals for potential carcinogenicity.

  1. 32P-Postlabeling test for covalent DNA binding of chemicals in vivo: Application to a variety of aromatic carcinogens and methylating agents

    International Nuclear Information System (INIS)

    Carcinogen--DNA adducts were detected and determined by 32P-postlabeling assay after exposure of mouse or rat tissues in vivo to a total of 28 compounds comprising 7 arylamines and derivatives, 3 azo compounds, 2 nitroaromatics, 12 polycyclic aromatic hydrocarbons, and 4 methylating agents. DNA was isolated from mouse skin, mouse liver, and rat liver after treatment with the individual carcinogens, then digested enzymatically to deoxyribonucleoside 3'-monophosphates, which were converted to 5'-32P-labeled deoxyribonucleoside 3',5'-bisphosphates by T4 polynucleotide kinase-catalyzed [32P]phosphate transfer from [gamma-32P]ATP. The nucleotides were resolved by anion-exchange t.l.c. on polyethyleneimine-cellulose and detected by autoradiography. The determination of low levels of DNA binding of the aromatic carcinogens entailed the removal of normal nucleotides prior to the resolution of adduct nucleotides. For this purpose, an alternative procedure employing reversed-phase t.l.c. was devised which offered advantages for the detection of quantitatively minor adducts. The procedures described enabled the detection of 1 aromatic DNA adduct in approximately 10(8) normal nucleotides, while the limit of detection of methylated adducts was 1 adduct in approximately 6 X 10(5) nucleotides. The results show that a great number of carcinogen-DNA adducts of diverse structure are substrates for 32P-labeling by polynucleotide kinase-catalyzed phosphorylation. Because covalent DNA adduct formation in vivo appears to be an essential property of the majority of chemical carcinogens, 32P-postlabeling analysis of carcinogen--DNA adducts in mammalian tissues may serve as a test for the screening of chemicals for potential carcinogenicity

  2. Carcinogenicity of the antineoplastic agent, 5-(3,3-dimethyl-1-triazeno)-imidazole-4-carboxamide, and its metabolites in rats.

    Science.gov (United States)

    Beal, D D; Skibba, J L; Croft, W A; Cohen, S M; Bryan, G T

    1975-04-01

    Chronic oral administration of the antineoplastic agent, 5-(3,3-dimethyl-1-triazeno)imidazole-4-carboxamide (NSC-45388, DTIC), induced predominantly thymic and mammary tumors as demonstrated previously. Male and female Sprague-Dawley and female Buffalo rats were susceptible to the carcinogenicity of DTIC. A 50% incidence of mammary adenocarcinomas was induced in males within 18 weeks. Type of tumor and tumor incidence were dose dependent. Single and multiple intraperitoneal injections of DTIC did not alter organ specificity. DTIC-induced thymic lymphosarcomas and mammary adenocarcinomas were transplantable. Tissue distribution studies revealed no correlation between uptake of DTIC by a given tissue and its susceptibility to carcinogenicity. Metabolites of DTIC were tested for carcinogenic activity. Animals administered 5-diazoimidazole-4-carboxamide orally, intraperitoneally, or intragastrically developed low incidences of thymic, stomach, bladder, or mammary tumors. A low incidence of mammary tumors developed in rats fed 2-azahypoxanthine. A variety of tumors, including several ependymoblastomas, were induced in rats that received 5-aminoimidazole-4-carboxamide orally. 5-(3-Methyl-1-triazeno)imidazole-4-carboxamide (MTIC), when fed or given in single or multiple intraperitoneal injections, induced a high incidence of mammary adenofibromas and a low incidence of uterine leiomyosarcomas. Control rats had low incidences of mammary adenocarcinomas and adenofibromas after 52 weeks. These data show that the carcinogenic properties of DTIC resemble those of carcinogenic N-nitroso compounds, hydrazine, azo, and azoxy-alkanes and aryltriazenes and thus suggest similar mechanism(s) of action. These data also indicate that MTIC is involved in the induction of mammary adenofibromas and uterine leiomyosarcomas by DTIC.

  3. Father's occupational exposure to carcinogenic agents and childhood acute leukemia: a new method to assess exposure (a case-control study

    Directory of Open Access Journals (Sweden)

    Rodriguez-Rivera Maria

    2008-01-01

    Full Text Available Abstract Background Medical research has not been able to establish whether a father's occupational exposures are associated with the development of acute leukemia (AL in their offspring. The studies conducted have weaknesses that have generated a misclassification of such exposure. Occupations and exposures to substances associated with childhood cancer are not very frequently encountered in the general population; thus, the reported risks are both inconsistent and inaccurate. In this study, to assess exposure we used a new method, an exposure index, which took into consideration the industrial branch, specific position, use of protective equipment, substances at work, degree of contact with such substances, and time of exposure. This index allowed us to obtain a grade, which permitted the identification of individuals according to their level of exposure to known or potentially carcinogenic agents that are not necessarily specifically identified as risk factors for leukemia. The aim of this study was to determine the association between a father's occupational exposure to carcinogenic agents and the presence of AL in their offspring. Methods From 1999 to 2000, a case-control study was performed with 193 children who reside in Mexico City and had been diagnosed with AL. The initial sample-size calculation was 150 children per group, assessed with an expected odds ratio (OR of three and a minimum exposure frequency of 15.8%. These children were matched by age, sex, and institution with 193 pediatric surgical patients at secondary-care hospitals. A questionnaire was used to determine each child's background and the characteristics of the father's occupation(s. In order to determine the level of exposure to carcinogenic agents, a previously validated exposure index (occupational exposure index, OEI was used. The consistency and validity of the index were assessed by a questionnaire comparison, the sensory recognition of the work area, and an

  4. Interaction and UV-Stability of Various Organic Capping Agents on the Surface of Anatase Nanoparticles

    Directory of Open Access Journals (Sweden)

    Mohsin Raza

    2014-04-01

    Full Text Available Anatase nanoparticles synthesized by the sol-gel method were surface-functionalized with long alkyl chain coupling agents as compatibilizers for a nonpolar environment, containing different anchor groups for surface interaction namely phosphonate (dodecyl phosphonate, carboxylate (dodecanoic acid, sulfate (sodium dodecyl sulphate, and amine (dodecyl amine. It was shown that the surface of the nanoparticles can be functionalized with the various surface groups applying similar reaction conditions. The kind of surface interaction was analyzed applying FTIR spectroscopy. The phosphonate and the carboxylate groups interact with the surface via quite strong covalent or coordinative interactions, respectively. The sulfate and amine based coupling agents on the other hand exhibit electrostatic interactions. UV stability studies of the surface bound groups revealed different degradation mechanisms for the various functionalities and moreover showed that phosphonates are the most stable among the investigated surface capping groups.

  5. UV-generated free radicals (FR) in skin: Their prevention by sunscreens and their induction by self-tanning agents

    Science.gov (United States)

    Jung, K.; Seifert, M.; Herrling, Th.; Fuchs, J.

    2008-05-01

    In the past few years, the cellular effects of ultraviolet (UV) irradiation induced in skin have become increasingly recognized. Indeed, it is now well known that UV irradiation induces structural and cellular changes in all the compartments of skin tissue. The generation of reactive oxygen species (ROS) is the first and immediate consequence of UV exposure and therefore the quantitative determination of free radical reactions in the skin during UV radiation is of primary importance for the understanding of dermatological photodamage. The RSF method (radical sun protection factor) herein presented, based on electron spin resonance spectroscopy (ESR), enables the measurement of free radical reactions in skin biopsies directly during UV radiation. The amount of free radicals varies with UV doses and can be standardized by varying UV irradiance or exposure time. The RSF method allows the determination of the protective effect of UV filters and sunscreens as well as the radical induction capacity of self-tanning agents as dihydroxyacetone (DHA). The reaction of the reducing sugars used in self-tanning products and amino acids in the skin layer (Maillard reaction) leads to the formation of Amadori products that generate free radicals during UV irradiation. Using the RSF method three different self-tanning agents were analyzed and it was found, that in DHA-treated skin more than 180% additional radicals were generated during sun exposure with respect to untreated skin. For this reason the exposure duration in the sun must be shortened when self-tanners are used and photoaging processes are accelerated.

  6. Mutational interactions between near-UV radiation and DNA damaging agents in Escherichia coli: the role of near-UV-induced modifications in growth and macromolecular synthesis

    International Nuclear Information System (INIS)

    The mutational interactions between near-ultraviolet (334 nm, 365 nm) radiation and DNA damaging agents (far-UV (254 nm) and ethyl-methanesulphonate (EMS)) were studied in strains of Escherichia coli B/r trp thy with different susceptibilities to near-UV-induced growth delay (wild-type, rel and sr). Far-UV induced reversion to tryptophan independence is reduced while forward mutation to streptomycin is enhanced by prior exposure of the rel+ srd+ strains to near-UV radiation. The observed interactions are reduced (rel) or absent (srd) in the two mutant strains as are the corresponding growth and macromolecular synthesis delays normally observed after near-UV treatment. Quantitatively, the degree of interaction induced by near-UV pre-treatment correlates closely with the degree of protein synthesis inhibition. A mechanism is proposed for the contrasting interactions at the two genetic loci based on the different pathways by which pre-mutagenic lesions may be processed. The primary chromophore for the mutational interactions would appear to be 4-thiouracil-containing transfer RNA. (author)

  7. Chemopreventive Effects of the p53-Modulating Agents CP-31398 and Prima-1 in Tobacco Carcinogen-Induced Lung Tumorigenesis in A/J Mice

    Directory of Open Access Journals (Sweden)

    Chinthalapally V. Rao

    2013-09-01

    Full Text Available Lung cancer is the leading cause of cancer deaths worldwide. Expression of the p53 tumor suppressor protein is frequently altered in tobacco-associated lung cancers. We studied chemopreventive effects of p53-modulating agents, namely, CP-31398 and Prima-1, on 4-(methylnitrosamino-1-(3-pyridyl-1-butanone (NNK-induced lung adenoma and adenocarcinoma formation in female A/J mice. Seven-week-old mice were treated with a single dose of NNK (10 µmol/mouse by intraperitoneal injection and, 3 weeks later, were randomized to mice fed a control diet or experimental diets containing 50 or 100 ppm CP-31398 or 150 or 300 ppm Prima-1 for either 17 weeks (10 mice/group or 34 weeks (15 mice/group to assess the efficacy against lung adenoma and adenocarcinoma. Dietary feeding of 50 or 100 ppm CP-31398 significantly suppressed (P < .0001 lung adenocarcinoma by 64% and 73%, respectively, after 17 weeks and by 47% and 56%, respectively, after 34 weeks. Similarly, 150 or 300 ppm Prima-1 significantly suppressed (P < .0001 lung adenocarcinoma formation by 56% and 62%, respectively, after 17 weeks and 39% and 56%, respectively, after 34 weeks. Importantly, these results suggest that both p53 modulators cause a delay in the progression of adenoma to adenocarcinoma. Immunohistochemical analysis of lung tumors from mice exposed to p53-modulating agents showed a significantly reduced tumor cell proliferation and increased accumulation of wild-type p53 in the nucleus. An increase in p21- and apoptotic-positive cells was also observed in lung tumors of mice exposed to p53-modulating agents. These results support a chemopreventive role of p53-modulating agents in tobacco carcinogen-induced lung adenocarcinoma formation.

  8. Multiple functional UV devices based on III-Nitride quantum wells for biological warfare agent detection

    Science.gov (United States)

    Wang, Qin; Savage, Susan; Persson, Sirpa; Noharet, Bertrand; Junique, Stéphane; Andersson, Jan Y.; Liuolia, Vytautas; Marcinkevicius, Saulius

    2009-02-01

    We have demonstrated surface normal detecting/filtering/emitting multiple functional ultraviolet (UV) optoelectronic devices based on InGaN/GaN, InGaN/AlGaN and AlxGa1-xN/AlyGa1-yN multiple quantum well (MQW) structures with operation wavelengths ranging from 270 nm to 450 nm. Utilizing MQW structure as device active layer offers a flexibility to tune its long cut-off wavelength in a wide UV range from solar-blind to visible by adjusting the well width, well composition and barrier height. Similarly, its short cut-off wavelength can be adjusted by using a GaN or AlGaN block layer on a sapphire substrate when the device is illuminated from its backside, which further provides an optical filtering effect. When a current injects into the device under forward bias the device acts as an UV light emitter, whereas the device performs as a typical photodetector under reverse biases. With applying an alternating external bias the device might be used as electroabsorption modulator due to quantum confined Stark effect. In present work fabricated devices have been characterized by transmission/absorption spectra, photoresponsivity, electroluminescence, and photoluminescence measurements under various forward and reverse biases. The piezoelectric effect, alloy broadening and Stokes shift between the emission and absorption spectra in different InGaN- and AlGaN-based QW structures have been investigated and compared. Possibilities of monolithic or hybrid integration using such multiple functional devices for biological warfare agents sensing application have also be discussed.

  9. Investigating the stability of gadolinium based contrast agents towards UV radiation.

    Science.gov (United States)

    Birka, Marvin; Roscher, Jörg; Holtkamp, Michael; Sperling, Michael; Karst, Uwe

    2016-03-15

    Since the 1980s, the broad application of gadolinium(Gd)-based contrast agents for magnetic resonance imaging (MRI) has led to significantly increased concentrations of Gd in the aqueous environment. Little is known about the stability of these highly polar xenobiotics under environmental conditions, in wastewater and in drinking water treatment. Therefore, the stability of frequently applied Gd-based MRI contrast agents towards UV radiation was investigated. The hyphenation of hydrophilic interaction liquid chromatography (HILIC) with inductively coupled plasma mass spectrometry (ICP-MS) and of HILIC with electrospray ionization mass spectrometry (ESI-MS) provided quantitative elemental information as well as structural information. The contrast agents Gd-DTPA, Gd-DOTA and Gd-BT-DO3A showed a high stability in irradiation experiments applying a wavelength range from 220 nm to 500 nm. Nevertheless, the degradation of Gd-BOPTA as well as the formation of Gd-containing transformation products was observed by means of HILIC-ICP-MS. Matrix-dependent irradiation experiments showed a degradation of Gd-BOPTA down to 3% of the initial amount in purified water after 300 min, whereas the degradation was slowed down in drinking water and surface water. Furthermore, it was observed that the sum of species continuously decreased with proceeding irradiation in all matrices. After irradiation in purified water for 300 min only 16% of the sum of species was left. This indicates a release of Gd(III) ions from the complex in course of irradiation. HILIC-ESI-MS measurements revealed that the transformation products mostly resulted from O-dealkylation and N-dealkylation reactions. In good correlation with retention times, the majority of transformation products were found to be more polar than Gd-BOPTA itself. Based on accurate masses, sum formulas were obtained and structures could be proposed. PMID:26802476

  10. UV-induced immune suppression and photocarcinogenesis: Chemoprevention by dietary botanical agents

    OpenAIRE

    Santosh K. Katiyar

    2007-01-01

    Studies of immune-suppressed transplant recipients and patients with biopsy-proven skin cancer have confirmed that ultraviolet (UV) radiation-induced immune suppression is a risk factor for the development of skin cancer in humans. UV radiation suppresses the immune system in several ways. The UVB spectrum inhibits antigen presentation, induces the release of immunosuppressive cytokines, and elicits DNA damage that is a molecular trigger of UV-mediated immunosuppression. It is therefore impor...

  11. Oxidative Stress in the Carcinogenicity of Chemical Carcinogens

    Directory of Open Access Journals (Sweden)

    Hideki Wanibuchi

    2013-10-01

    Full Text Available This review highlights several in vivo studies utilizing non-genotoxic and genotoxic chemical carcinogens, and the mechanisms of their high and low dose carcinogenicities with respect to formation of oxidative stress. Here, we survey the examples and discuss possible mechanisms of hormetic effects with cytochrome P450 inducers, such as phenobarbital, a-benzene hexachloride and 1,1-bis(p-chlorophenyl-2,2,2-trichloroethane. Epigenetic processes differentially can be affected by agents that impinge on oxidative DNA damage, repair, apoptosis, cell proliferation, intracellular communication and cell signaling. Non-genotoxic carcinogens may target nuclear receptors and induce post-translational modifications at the protein level, thereby impacting on the stability or activity of key regulatory proteins, including oncoproteins and tumor suppressor proteins. We further discuss role of oxidative stress focusing on the low dose carcinogenicities of several genotoxic carcinogens such as a hepatocarcinogen contained in seared fish and meat, 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline, arsenic and its metabolites, and the kidney carcinogen potassium bromate.

  12. Oxidative Stress in the Carcinogenicity of Chemical Carcinogens

    Energy Technology Data Exchange (ETDEWEB)

    Kakehashi, Anna; Wei, Min [Department of Pathology, Osaka City University Graduate School of Medicine, 1-4-3 Asahi-machi, Abeno-Ku, Osaka 545-8585 (Japan); Fukushima, Shoji [Japan Bioassay Research Center, Japan Industrial Safety and Health Association, 2445 Hirasawa, Hadano, Kanagawa 257-0015 (Japan); Wanibuchi, Hideki, E-mail: wani@med.osaka-cu.ac.jp [Department of Pathology, Osaka City University Graduate School of Medicine, 1-4-3 Asahi-machi, Abeno-Ku, Osaka 545-8585 (Japan)

    2013-10-28

    This review highlights several in vivo studies utilizing non-genotoxic and genotoxic chemical carcinogens, and the mechanisms of their high and low dose carcinogenicities with respect to formation of oxidative stress. Here, we survey the examples and discuss possible mechanisms of hormetic effects with cytochrome P{sub 450} inducers, such as phenobarbital, α-benzene hexachloride and 1,1-bis(p-chlorophenyl)-2,2,2-trichloroethane. Epigenetic processes differentially can be affected by agents that impinge on oxidative DNA damage, repair, apoptosis, cell proliferation, intracellular communication and cell signaling. Non-genotoxic carcinogens may target nuclear receptors and induce post-translational modifications at the protein level, thereby impacting on the stability or activity of key regulatory proteins, including oncoproteins and tumor suppressor proteins. We further discuss role of oxidative stress focusing on the low dose carcinogenicities of several genotoxic carcinogens such as a hepatocarcinogen contained in seared fish and meat, 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline, arsenic and its metabolites, and the kidney carcinogen potassium bromate.

  13. Degradation of sunscreen agent p-aminobenzoic acid using a combination system of UV irradiation, persulphate and iron(II).

    Science.gov (United States)

    Xue, Yicen; Dong, Wenbo; Wang, Xiaoning; Bi, Wenlong; Zhai, Pingping; Li, Hongjing; Nie, Minghua

    2016-03-01

    Increased usage and discharge of sunscreens have led to ecological safety crisis, and people are developing the advanced oxidation processes (AOPs) to treat them. The present study aimed to determine the degradation efficiency and mechanism of the sunscreen agent p-aminobenzoic acid (PABA) using the UV/Fe(2+)/persulphate (PS) method. A series of irradiation experiments were conducted to optimise the system conditions and to study the impacts of the natural anion. Free radicals and degradation products were identified in order to clarify the degradation mechanism. Initial PS and Fe(2+) concentrations showed significant impacts on PABA degradation. Natural anions, such as Cl(-), NO3 (-), H2PO4 (-) and HCO3 (-), impeded PABA degradation because of ion (Fe(2+)) capture, radical scavenging or pH effects. Hydroxyl (HO·) and sulphate (SO4 (·-)) radicals were two main radicals observed in the UV/Fe(2+)/PS system; of these, SO4 (·-) showed greater effects on PABA degradation. Over 99 % of the available PABA was completely degraded into carbon dioxide (CO2) and water (H2O) by the UV/Fe(2+)/PS system, and the remaining PABA participated in complex radical reactions. By-products were identified by total ion chromatography and mass spectrometry. Our research provides a treatment process for PABA with high degradation efficiency and environmental safety and introduces a new strategy for sunscreen degradation.

  14. Using carcinogenic agents in the research laboratories. Rules and procedure; Norme e procedure per l'utilizzo di agenti cancerogeni nei laboratori di ricerca

    Energy Technology Data Exchange (ETDEWEB)

    Lombard, C.C.; Mancini, C. [ENEA, Centro Ricerche Casaccia, Rome (Italy). Dipt. Ambiente

    1999-07-01

    The carcinogenic risk represents a main problem of Health and Safety at Work Act. Chemical carcinogens regulation has been recently improved by the Italian Decree No. 626/94. The aim of the present work is to outline the criteria for the protection of working people in a complex workplace such as research laboratories, focusing on its peculiar occupational health factors, such as the hazardous exposure to a vast array of chemicals also due to the frequent turnover in the personnel activities. [Italian] Il tema dell'esposizione ad agenti cancerogeni costituisce un vasto e complesso problema di igiene del lavoro e medicina preventiva. Limitatamente ai cancerogeni chimici, un impulso importante in materia di prevenzione e' venuto dalla promulgazione del D.lgs. 626/94 e successive modificazioni. Il presente lavoro ha lo scopo di fornire indicazioni concrete per la messa in atto delle misure di prevenzione e protezione dei lavoratori, ponendo particolare attenzione ai laboratori di ricerca che costituiscono ambienti lavorativi, particolari caratterizzati dal gran numero di agenti manipolati e dal continuo mutamento delle attivita' e del personale.

  15. Final LDRD report : development of advanced UV light emitters and biological agent detection strategies.

    Energy Technology Data Exchange (ETDEWEB)

    Figiel, Jeffrey James; Crawford, Mary Hagerott; Banas, Michael Anthony; Farrow, Darcie; Armstrong, Andrew M.; Serkland, Darwin Keith; Allerman, Andrew Alan; Schmitt, Randal L.

    2007-12-01

    We present the results of a three year LDRD project which has focused on the development of novel, compact, ultraviolet solid-state sources and fluorescence-based sensing platforms that apply such devices to the sensing of biological and nuclear materials. We describe our development of 270-280 nm AlGaN-based semiconductor UV LEDs with performance suitable for evaluation in biosensor platforms as well as our development efforts towards the realization of a 340 nm AlGaN-based laser diode technology. We further review our sensor development efforts, including evaluation of the efficacy of using modulated LED excitation and phase sensitive detection techniques for fluorescence detection of bio molecules and uranyl-containing compounds.

  16. Carcinogenic effects of radiation-introduction

    International Nuclear Information System (INIS)

    The weight of experimental evidence reviewed indicates that UV damage to DNA, probably pyrimidine dimers, is the best molecular candidate for the initiating damage that leads to skin cancer. It is postulated that the carcinogenic action spectrum should be similar to the DNA action spectrum filtered through the upper layer of skin

  17. Carcinogenicity and teratogenicity vs. psychogenicity: Psychological characteristics associated with self-reported Agent Orange exposure among Vietnam combat veterans who seek treatment for substance abuse

    Energy Technology Data Exchange (ETDEWEB)

    Robinowitz, R.; Roberts, W.R.; Dolan, M.P.; Patterson, E.T.; Charles, H.L.; Atkins, H.G.; Penk, W.E. (Univ. of Texas Health Science Center, Dallas (USA))

    1989-09-01

    This study asked, What are the psychological characteristics of Vietnam combat veterans who claim Agent Orange exposure when compared with combat-experienced cohorts who do not report such contamination The question was researched among 153 heroin addicts, polydrug abusers, and chronic alcoholics who were seeking treatment: 58 reported moderate to high defoliant exposure while in combat; 95 reported minimal to no exposure while in Vietnam. The null hypothesis was accepted for measures of childhood and present family social climate, premilitary backgrounds, reasons for seeking treatment, patterns and types of illicit drug and alcohol use, interpersonal problems, intellectual functioning, and short-term memory. The null hypothesis was rejected for personality differences, however, those who self-reported high Agent Orange exposure scored significantly higher on MMPI scales F, Hypochondriasis, Depression, Paranoia, Psychasthenia, Schizophrenia, Mania, and Social interoversion. The results suggest that clinicians carefully assess attributional processing of those who report traumatic experience.

  18. The ISS Carcinogens Data Bank (BDC).

    Science.gov (United States)

    Binetti, Roberto; Ceccarelli, Federica; Costamagna, Francesca Marina; D'Angiolini, Antonella; Fabri, Alessandra; Ferri, Maurizio; Riva, Giovanni; Roazzi, Paolo; Trucchi, Daniela; Marcello, Ida

    2008-01-01

    The Data Bank on Carcinogens (Banca Dati Cancerogeni, BDC) is a factual data bank, available on the Istituto Superiore di Sanità website, aimed at supporting the risk management decision making of central and local administrators. It can also represent a valuable tool for industry. The available information on carcinogenicity evaluations/classifications produced by European Union and by other institutions (IARC, USEPA, NTP, CCTN) is presented in a concise form accompanied by bibliographic references enabling the users to consult the original sources and, in some cases, to be directly connected to the relevant website. The classifications carried out by each organization in accordance with its own criteria assign the examined agents to specific qualitative categories and do not include quantitative assessment. BDC intends to provide an easy tool for experts, researchers and risk managers dealing with carcinogenic agents. PMID:18469374

  19. Pretreatment with UV light renders the chromatin in human fibroblasts more susceptible to the DNA-damaging agents bleomycin, gamma radiation and 8-methoxypsoralen

    International Nuclear Information System (INIS)

    Confluent human fibroblast cultures were pretreated with either 254 nm UV light (UV) or methyl methanesulphonate (MMS), incubated at 370C and subsequently challenged on ice with bleomycin (BLM), gamma-radiation or 8-methoxy-psoralen (MOP). The resulting number of challenge-induced DNA damages (measured as DNA strand breaks or cross-links) were compared with the numbers induced in similarly challenged but non-pretreated control cells. It was found that the timing of the subsequent challenge of cells pretreated with UV did significantly affect the amount of induced DNA damage. When the challenging agents were administered after a 10-20 min incubation period following UV pretreatment, the amount of induced DNA damage was increased 50% over control cells. In contrast, the timing of the subsequent challenge of cells pretreated with MMS has no influence on the level of challenge-induced damage. It is hypothesized that UV-irradiated chromatin undergoes a time-dependent decondensation that renders it more susceptible to the induction of strand breaks and cross-links by BLM, gamma-radiation and MOP. A possible role for chromatin decondensation in UV-induced excision repair is discussed. (author)

  20. [Leather azo dyes: mutagenic and carcinogenic risks].

    Science.gov (United States)

    Clonfero, E; Venier, P; Granella, M; Levis, A G

    1990-01-01

    The paper reviews the carcinogenicity and mutagenicity data on azo dyes used in the leather industry. Two water soluble benzidine-based dyes were classified as "probably carcinogenic to humans" by the International Agency for Research on Cancer (IARC). No other dyes have been evaluated by the IARC. Of the 48 azo dyes assayed in the Salmonella/microsome test, 20 gave positive results. Attention is drawn to the important role of the in vivo metabolism of azo compounds, which includes a preliminary reduction of the azo bonds and subsequent release of the aromatic amines of the dye. A useful assay (Prival test) for evaluating the mutagenic properties of azo dyes involves a reductive step that permits the release of any genotoxic agents present in the compounds. A list of leather azo dyes is furnished that are considered as potentially harmful due to the presence of a carcinogenic aromatic amine (benzidine, p-aminobenzene and derivatives) in their formulae.

  1. Food derived carcinogenic amnoimidazoazaarenes

    DEFF Research Database (Denmark)

    Frandsen, Henrik

    Carcinogenic aminoimidazoazaarenes are formed during cooking of meat and fish. Important factors for the formation of these compounds are meat type, cooking temperature and time. The compounds are genotoxic in bacterial and mammalian cells. In animal feeding studies the compounds tested so far we...... of the exocyclic amino group. Estimations of human cancer risk have indicated that ingestion of food containing aminoimidazoazaarenes are of importance....... found to be multiple organ carcinogens. The aminoimidazoazaarenes are metabolically activated by hydroxylation of the exocyclic aminogroup to the N-hydroxyamino derivative. The resultant proximate mutagens often need further activation by phase II transferases for formation of reactive species that form...

  2. Carcinogen risk assessment

    International Nuclear Information System (INIS)

    This article describes the methods by which risk factors for carcinogenic hazards are determined and the limitations inherent in the process. From statistical and epidemiological studies, the major identifiable factors related to cancer in the United States were determined to be cigarette smoking, diet, reproductive and sexual behavior, infections, ultraviolet and ionizing radiation, and alcohol consumption. The incidence of lung cancer due to air pollutants was estimated to be less than 2%. Research needs were discussed

  3. The carcinogenicity of chromium

    OpenAIRE

    Norseth, Tor

    1981-01-01

    The carcinogenicity of chromium compounds is reviewed with specific attention to the gaps in knowledge for risk estimation and research needs. The most important problems at present are whether trivalent chromium compounds cause cancer, and whether there is a difference in cancer causing effects between the soluble and the slightly soluble hexavalent compounds in the practical exposure situation. Dose estimates for risk estimation based on epidemiological investigations are also lacking. Pres...

  4. Chemistry of carcinogenic metals.

    OpenAIRE

    Martell, A E

    1981-01-01

    The periodic distribution of known and suspected carcinogenic metal ions is described, and the chemical behavior of various types of metal ions is explained in terms of the general theory of hard and soft acids and bases. The chelate effect is elucidated, and the relatively high stability of metal chelates in very dilute solutions is discussed. The concepts employed for the chelate effect are extended to explain the high stabilities of macrocyclic and cryptate complexes. Procedures for the us...

  5. Response of human epidermal keratinocytes to UV light

    International Nuclear Information System (INIS)

    This thesis presents a study on the response of human epidermal keratinocytes to UV light as well as to other agents like 4-NQO and TPA. The effects of ultraviolet (UV) light on the protein synthesis in cultured keratinocytes are presented in ch. III. The next chapter describes the construction of a cDNA library using mRNA isolated from UV irradiated kernatinocytes. This library was differentially screened with cDNA probes synthesized on mRNA from either UV irradiated or nonirradiated cells. Several groups of cDNA clones corresponding to transcripts whose level in the cytoplasm seem to be affected by exposure to UV light have been isolated and characterized by cross-hybridization, sequencing and Northern blot analysis. More detailed analysis of some of the cDNA clones is presented in the two chapters following ch. IV. The complete cDNA sequence of the proteinase inhibitor cystatin A and the modulation of its expression by UV light and the carcinogen 4-nitroquinoline 1-oxide (4-NQO) in keratinocytes are described in ch. V. Two other groups of cDNA clones have been isolated which do not cross-hybridize with each other on Southern blots. However, the primary structures of the proteins deduced from the nucleotide sequences of these two groups of cDNA clones are very similar. 212 refs.; 33 figs.; 2 tabs

  6. Cytotoxic and mutagenic effects of carcinogenic aromatic amides and polycyclic hydrocarbons and ultraviolet irradiation in normally repairing and repair-deficient (xeroderma pigmentosum) diploid human skin fibroblasts

    International Nuclear Information System (INIS)

    The cloning ability of fibroblasts taken from a xeroderma pigmentosum patient proved 2.5 to 3.5 times more sensitive to the cytotoxic effect of active derivatives of carcinogens or to uv irradiation than that of normal cells. They also exhibited a corresponding 2.5- to 3.5-fold greater increase in the frequency of induced mutations to 8-azaguanine resistance per survivor, which might have been expected since these XP cells exhibit less than 20 percent of the DNA-repairing capacity of the normal cells following exposure to such DNA-damaging agents

  7. Comparison of rat olfactory mucosal responses to carcinogenic and non-carcinogenic chloracetanilides

    Science.gov (United States)

    Genter, M.B.; Warner, B.M.; Medvedovic, M.; Sartor, M.A.

    2009-01-01

    Alachlor and butachlor are chloracetanilide herbicides that induce olfactory tumors in rats, whereas propachlor does not. The mechanism by which alachlor induces tumors is distinct from many other nasal carcinogens, in that alachlor induces a gradual de-differentiation of the olfactory mucosa (OM) to a more respiratory-like epithelium, in contrast to other agents that induce cytotoxicity, followed by an aberrant regenerative response. We studied biochemical and genomic effects of these compounds to identify processes that occur in common between alachlor- and butachlor-treated rats. Because we have previously shown that matrix metalloproteinase-2 (MMP2) is activated in OM by alachlor, in the present studies we evaluated both MMP2 activation and changes in OM gene expression in response to carcinogenic and non-carcinogenic chloracetanilide treatments. All three chloracetanilides activated MMP2, and > 300 genes were significantly up- or downregulated between control and alachlor-treated rats. The most significantly regulated gene was vomeromodulin, which was dramatically upregulated by alachlor and butachlor treatment (>60-fold), but not by propachlor treatment. Except for similar gene responses in alachlor- and butachlor-treated rats, we did not identify clear-cut differences that would predict OM carcinogenicity in this study. PMID:19425180

  8. HPLC-UV Method for the Identification and Screening of Hydroquinone, Ethers of Hydroquinone and Corticosteroids Possibly Used as Skin-Whitening Agents in Illicit Cosmetic Products.

    Science.gov (United States)

    Gimeno, Pascal; Maggio, Annie-Françoise; Bancilhon, Marjorie; Lassu, Nelly; Gornes, Hervé; Brenier, Charlotte; Lempereur, Laurent

    2016-03-01

    Corticosteroids, hydroquinone and its ethers are regulated in cosmetics by the Regulation 1223/2009. As corticosteroids are forbidden to be used in cosmetics and cannot be present as contaminants or impurities, an identification of one of these illicit compounds deliberately introduced in these types of cosmetics is enough for market survey control. In order to quickly identify skin-whitening agents present in illegal cosmetics, this article proposes an HPLC-UV method for the identification and screening of hydroquinone, 3 ethers of hydroquinone and 39 corticosteroids that may be found in skin-whitening products. Two elution gradients were developed to separate all compounds. The main solvent gradient (A) allows the separation of 39 compounds among the 43 compounds considered in 50 min. Limits of detection on skin-whitening cosmetics are given. For compounds not separated, a complementary gradient elution (B) using the same solvents is proposed. Between 2004 and 2009, a market survey on "skin-whitening cosmetic" was performed on 150 samples and highlights that more than half of the products tested do not comply with the Cosmetic Regulation 1223/2009 (amending the Council Directive 76/768/EEC). PMID:26462503

  9. Alternative strawberry disease management strategy: combing low UV-C irradiation in dark, disabling pathogen’s UV-C repair mechanism, and preventing pathogen establishment with biocontrol agents

    Science.gov (United States)

    The limitations of current fungicides necessitate a search for new approaches. Low-dose or sub-lethal UV-C irradiation (12.36 J/m2) alone is not effective in controlling fungal diseases, especially when the plants are exposed to UV-C irradiation during the day. We found, however, that application ...

  10. Utilização de linhagens diplóides uvsH//uvsH de Aspergillus nidulans (Ascomycetes para a avaliação do potencial recombinagênico de agentes químicos e físicos uvsH//uvsH diploid strain favors an efficient method to evaluate the recombinagenic effect of chemical and physical agents in Aspergillus nidulans (Ascomycetes

    Directory of Open Access Journals (Sweden)

    Francielle Baptista

    2001-05-01

    Full Text Available O ascomiceto Aspergillus nidulans apresenta-se como um excelente sistema para o estudo da recombinação somática, por passar grande parte de seu ciclo celular em G2 e por apresentar mutações uvs que promovem aumento das freqüências normais de recombinação mitótica (uvsF e uvsH. O presente trabalho teve como objetivo obter uma nova linhagem diplóide de A. nidulans, com características apropriadas para estudos da recombinagênese, tais como: hetererozigose para marcadores nutricionais e de coloração de conidios e homozigose para a mutação uvsH. A maior sensibilidade do diplóide uvsH//uvsH no monitoramento de eventos de recombinação mitótica foi demonstrada através dos mais altos índices de recombinação mitótica espontânea por ele apresentados, em comparação com o diplóide uvsH+//uvsH +. A nova linhagem apresenta-se como uma ferramenta versátil, podendo ser utilizada em diferentes estudos relacionados à recombinação mitótica em A. nidulansAscomycete Aspergillus nidulans is an excellent system for mitotic crossing-over studies. This is due to the fact that much of its cell cycle is passed in G2 and presents uvs mutations that increase frequencies of normal mitotic recombinations (uvsF and uvsH. The aim of this research was to obtain a new diploid strain of A. nidulans with proper characteristics for recombinagenesis investigations, or rather, heterozygous for nutritional markers and conidia coloration and homozygous for uvsH mutation. Higher sensitivity of diploid uvsH//uvsH in the monitoring of mitotic recombination events was shown by higher indexes of the diploid’s spontaneous mitotic recombination when compared with diploid uvsH+//uvsH +. New strain is a versatile tool that may be used in different studies on mitotic recombination in A. nidulans

  11. Carcinogenicity of hair dye components.

    Science.gov (United States)

    Van Duuren, B L

    1980-03-01

    The available animal carcinogenicity data on hair dye components was reviewed. From this review it became clear that certain hair dye components, some of which are still in hair dye formulations now on the market, are animal carcinogens. The compounds of concern that are still in use are: 3-amino-4-methoxyaniline, 2-nitro-4-aminoaniline and 3-nitro-4-hydroxyaniline. Certain azo dyes formerly used, and related compounds still in use, contain the benzidine moiety. Two of these compounds, Direct Blue 6 and Direct Black 38, have been shown to be metabolized in animals to the human carcinogen benzidine. Furthermore, skin absorption studies carried out with radiolabeled hair dye components applied to animal or human skin have conclusively shown that these compounds are systemically absorbed and excreted. Known cocarcinogens such as catechol and pyrogallol, which enhance benzo(a)pyrene carcinogenicity on mouse skin, are used as hair dye components. It is not known whether such compounds will enhance the carcinogenicity of substituted aniline hair dye chemicals. The available epidemiologic data are not sufficient to link hair dye use with an increased incidence in human cancer.

  12. Occurrence, uses, and carcinogenicity of arylamines.

    Science.gov (United States)

    Chung, King-Thom

    2015-01-01

    Arylamines are chemically synthesized and contained in oxidants, epoxy polymers, explosives, fungicides, pesticides, colorants, polyurethanes, and used in rubber, pharmacology, cosmetics, and other chemical industries. Many arylamines are ubiquitously present in cigarette smoke, cooking fume hoods, foods, automobile exhaust, industrial sites, etc. Some arylamines can be generated through azo reduction by intestinal, skin, and environmental microorganisms from azo dyes that are widely used. Arylamines can also be generated by reduction of the nitro-group containing polyhydrated hydrocarbons including muntions. Some arylamines are released by burning nitrogen containing organic materials at high temperatures. Some medical drugs are also arylamines. Furthermore, many arylamines are essential constituents of normal metabolism or the result of abnormal metabolism or dietary sources. Some arylamines are mutagenic, carcinogenic or the cause of other kinds of maladies. Some arylamine are considered the major etiological agents of bladder tumors in humans and animals but may also induce other types of cancers in various organs. The organ, tissue, and species specificity of the arylamine-inducing carcinogenesis may be determined by their availability, distribution, and the presence of metabolic activation/detoxicification enzymes of each organ or tissue of different species. The ubiquitous arylamines, therefore, pose serious hazards to human health and environment. This article will address the occurrence, uses, carcinogenicity, and other arylamines-induced diseases.

  13. EVALUATION OF THE POTENTIAL CARCINOGENICITY OF CYCLOPHOSPHAMIDE

    Science.gov (United States)

    Cyclophosphamide is a probable human carcinogen, classified as weight-of-evidence Group B1 under the EPA Guidelines for Carcinogen Risk Assessment (U.S. EPA, 1986a).Evidence on potential carcinogenicity from animal studies is "Sufficient," and the evidence from human studies is "...

  14. Evidence that uv-inducible error-prone repair is absent in Haemophilus influenzae Rd, with a discussion of the relation to error-prone repair of alkylating-agent damage

    Energy Technology Data Exchange (ETDEWEB)

    Kimball, R.F.; Boling, M.E.; Perdue, S.W.

    1977-01-01

    Haemophilus influenzae Rd and its derivatives are mutated either not at all or to only a very small extent by ultraviolet (uv) radiation, x rays, methyl methanesulfonate, and nitrogen mustard, though they are readily mutated by such agents as N-methyl-N'-nitro-N-nitrosoguanidine, ethyl methanesulfonate, and nitrosocarbaryl (NC). In these respects H. influenzae Rd resembles the lexA mutants of Escherichia coli that lack the SOS or reclex uv-inducible error-prone repair system. This similarity is further brought out by the observation that chloramphenicol has little or no effect on post-replication repair after uv irradiation. In E. coli, chloramphenicol has been reported to considerably inhibit post-replication repair in the wild type but not in the lexA mutant. Earlier work has suggested that most or all the mutations induced in H. influenzae by NC result from error-prone repair. Combined treatment with NC and either x rays or uv shows that the NC error-prone repair system does not produce mutations from the lesions induced by these radiations even while it is producing them from its own lesions. It is concluded that the NC error-prone repair system or systems and the reclex error-prone system are different.

  15. Carcinogenesis related to intense pulsed light and UV exposure

    DEFF Research Database (Denmark)

    Hedelund, L; Lerche, C; Wulf, H C;

    2006-01-01

    This study examines whether intense pulsed light (IPL) treatment has a carcinogenic potential itself or may influence ultraviolet (UV)-induced carcinogenesis. Secondly, it evaluates whether UV exposure may influence IPL-induced side effects. Hairless, lightly pigmented mice (n=144) received three...

  16. UV-induced skin damage

    International Nuclear Information System (INIS)

    Solar radiation induces acute and chronic reactions in human and animal skin. Chronic repeated exposures are the primary cause of benign and malignant skin tumors, including malignant melanoma. Among types of solar radiation, ultraviolet B (290-320 nm) radiation is highly mutagenic and carcinogenic in animal experiments compared to ultraviolet A (320-400 nm) radiation. Epidemiological studies suggest that solar UV radiation is responsible for skin tumor development via gene mutations and immunosuppression, and possibly for photoaging. In this review, recent understanding of DNA damage caused by direct UV radiation and by indirect stress via reactive oxygen species (ROS) and DNA repair mechanisms, particularly nucleotide excision repair of human cells, are discussed. In addition, mutations induced by solar UV radiation in p53, ras and patched genes of non-melanoma skin cancer cells, and the role of ROS as both a promoter in UV-carcinogenesis and an inducer of UV-apoptosis, are described based primarily on the findings reported during the last decade. Furthermore, the effect of UV on immunological reaction in the skin is discussed. Finally, possible prevention of UV-induced skin cancer by feeding or topical use of antioxidants, such as polyphenols, vitamin C, and vitamin E, is discussed

  17. Electrophoretic mobility of PM2 DNA treated with ultimate chemical carcinogens or with ultraviolet light

    International Nuclear Information System (INIS)

    Superhelical DNA of the Pseudomonas phage PM2 was irradiated with UV-light or reacted with covalently binding carcinogens, such as 7-bromomethyl-benz[a]anthracene, (Ac)2ONFln, K-region epoxides, and alkylating agents. Migration velocity of the DNA products was determined using agarose gel electrophoresis. In gels of more than 1.3%-1.9% agarose, modified PM2 DNA exhibited a dose-(concentration-)dependent decrease of migration velocity. This phenomenon is probably due to a decrease in superhelix density which caused the compact DNA coil to assume eventually an open-circular conformation. Comparison of the extent of DNA modification with the decrease of migration velocity revealed that the superhelical structure sensitively reflected the chemical DNA alterations. DNA species exhibiting in 1.6% agarose gels, a migration velocity of up to 30% of that of control DNA showed an increase of velocity in 0.4% agarose. Therefore, in 1.3%-1.9% agarose gels, the decrease of superhelix density is accompanied by an increase of the frictional coefficient, whereas in 0.4%-0.9% agarose gels the same decrease of superhelix density apparently led to a higher degree of flexibility of the macromolecule and/or exposure of additional electric charges. (orig.)

  18. Antiradiation UV Vaccine: UV Radiation, Biological effects, lesions and medical management - immune-therapy and immune-protection.

    Science.gov (United States)

    Popov, Dmitri; Jones, Jeffrey; Maliev, Slava

    moderate and high doses of UV and ionizing radiation induce cell death by necrosis and generate systemic inflammatory response syndrome (SIRS), toxic multiple organ injury (TMOI), toxic multiple organ dysfunction syndromes (TMODS),and finally, toxic multiple organ failure (TMOF). [D.Popov et al.2012, Fliedner T.et al. 2005, T. Azizova et al. 2004] UV-B is a complete carcinogen that is absorbed by DNA and directly damages DNA. DNA damage induced by UV-B irradiation typically includes the formation of cyclobutane pyrimidine dimmers (CPD) and 6-4 photoproducts (6-4P)[IARC, Working Group Reports, M.Saraiya et al. 2004]. The pre-vaccinated animals seem to have a blunted injury response relative to the unvaccinated animals, presumably by reduction in the inflammatory response and secondary injury effects. The mechanism of action of the antiradiation vaccine, needs further evaluation. Conclusion: A UV antiradiation vaccine appears to demonstrate efficacy as a prophylactic agent for acute solar burns and toxicity. An antiradiation UV vaccine could be used in conjunction with adjunctive measures, e.g. antioxidants and UV barriers to reduce UV radiation toxicity. The authors of this experiments would like to propose further development work of the antiradiation UV vaccine to enhance the armamentarium for prophylaxis and prevention of the various forms skin cancer.

  19. Analysis of mutagenic and carcinogenic risks: nitrates, nitrites, N-Nitroso compounds. Comparison with radioactive risks

    International Nuclear Information System (INIS)

    This report comes within the scope of the general studies on mutagenic and carcinogenic agents other than ionizing radiations. Through feeding, way of life and working activities, man is exposed to genotoxic risks of N-nitroso compounds (NNC). In spite of differences in the molecular modes of action, there exists some analogy between the effects of radiation exposures and those of NNC: DNA is the target in either instance. Unlike radiations, NNC are alkylating agents. The whole activation process of carcinogens arises from mechanisms leading to DNA repair

  20. UV Radiation and the Skin

    Directory of Open Access Journals (Sweden)

    Timothy Scott

    2013-06-01

    Full Text Available UV radiation (UV is classified as a “complete carcinogen” because it is both a mutagen and a non-specific damaging agent and has properties of both a tumor initiator and a tumor promoter. In environmental abundance, UV is the most important modifiable risk factor for skin cancer and many other environmentally-influenced skin disorders. However, UV also benefits human health by mediating natural synthesis of vitamin D and endorphins in the skin, therefore UV has complex and mixed effects on human health. Nonetheless, excessive exposure to UV carries profound health risks, including atrophy, pigmentary changes, wrinkling and malignancy. UV is epidemiologically and molecularly linked to the three most common types of skin cancer, basal cell carcinoma, squamous cell carcinoma and malignant melanoma, which together affect more than a million Americans annually. Genetic factors also influence risk of UV-mediated skin disease. Polymorphisms of the melanocortin 1 receptor (MC1R gene, in particular, correlate with fairness of skin, UV sensitivity, and enhanced cancer risk. We are interested in developing UV-protective approaches based on a detailed understanding of molecular events that occur after UV exposure, focusing particularly on epidermal melanization and the role of the MC1R in genome maintenance.

  1. Enhancement of DNA repair capacity of mammalian cells by carcinogen treatment

    International Nuclear Information System (INIS)

    To determine whether DNA excision repair is enhanced in mammalian cells in response to DNA damage, as it is in bacteria as part of the SOS response, we used an expression vector-host cell reactivation assay to measure cellular DNA repair capacity. When UV-damaged chloramphenicol acetyltransferase (CAT) vector DNA was introduced into monkey cells (CV-1), the level of CAT activity was inversely related to the UV fluence due to inhibition of CAT gene expression by UV photoproducts. When CV-1 cells were treated with either UV radiation or mitomycin C, 24-48 h before transfection, CAT expression from the UV-irradiated plasmid was increased. This increase also occurred in a line of normal human cells, but not in repair-deficient human xeroderma pigmentosum cells. We confirmed that this increase in CAT expression was due to repair, and not to production of damage-free templates by recombination; the frequency of generation of supF+ recombinants after transfection with UV-irradiated pZ189 vectors carrying different point mutations in the supF gene did not significantly increase in carcinogen-treated CV-1 cells. From these results we conclude that carcinogen treatment enhances the excision-repair capacity of normal mammalian cells

  2. 一种水性聚氨酯防紫外线涂层剂的应用%The application of an anti-UV waterborne polyurethane coating agent

    Institute of Scientific and Technical Information of China (English)

    李晓霞

    2014-01-01

    Coating method and nanotechnology was used to add the ultraviolet screening agent into water-PU coating. A thin nanoparticles film was formed on the fabric surface, in order to achieve the required anti-UV radiation performance;meanwhile, the fabric display air permeable and moisture permeable properties.%应用涂层方法和纳米技术将紫外线屏蔽剂添加到水性聚氨酯涂层胶中,在织物表面形成一层含有纳米微粒的薄膜用以达到所需的紫外线屏蔽效果;同时,织物具有透气、透湿性能。

  3. Foreign Brand Higher In Carcinogen

    Institute of Scientific and Technical Information of China (English)

    MATT; YOUNG

    2006-01-01

    It's no secret that cigarettes contain a lot of cancer-causing agents. Compared to local Chinese cigarettes, Marlboros contain a higher percentage according to a study published in a 2003 issue of Nicotine & Tobacco Research. "People not [involved] in the field believe a cigarette is a cigarette," said chief study author Dr. David Ashley. "In

  4. Development of HPLC and UV spectrophotometric methods for the determination of ascorbic acid using hydroxypropyl-{beta}-cyclodextrin and triethanolamine as photostabilizing agents

    Energy Technology Data Exchange (ETDEWEB)

    Garnero, Claudia [Departamento de Farmacia, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba, Ciudad Universitaria, 5000 Cordoba (Argentina); Longhi, Marcela, E-mail: mrlcor@fcq.unc.edu.ar [Departamento de Farmacia, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba, Ciudad Universitaria, 5000 Cordoba (Argentina)

    2010-02-05

    In this study, the effect of complex formation with triethanolamine (TEA) alone and in combination with hydroxypropyl-{beta}-cyclodextrin (HP-{beta}-CD) on the photostability of ascorbic acid was evaluated for exposure to artificial and diffuse daylight. The first-order rate constants for the photodegradation reactions were determined. The data obtained showed that these complexes strongly reduced the photodegradation process with an 11- and 35-fold increase in the photostability of ascorbic acid, depending of the ligand concentration and the irradiation source. The multicomponent complex gave a significantly better stabilization for exposure to light than TEA alone. Due to the fact that the complexation extended the exposure of ascorbic acid to light (without molecular changes), UV spectrophotometric and reversed phase high performance liquid chromatographic (HPLC) methods were developed for the quantitative determination of the vitamin in pure form and in pharmaceutical preparations. These methods were statistically validated, all the validation parameters were found to be within the acceptance range. These results demonstrate that the proposed methods are suitable for the quality control of ascorbic acid, providing simple, rapid, precise, accurate and convenient approaches for routine analysis of bulk drug and pharmaceutical formulations.

  5. Skin Cancer and UV Protection

    Directory of Open Access Journals (Sweden)

    Tarbuk Anita

    2016-03-01

    Full Text Available The incidence of skin cancer is increasing by epidemic proportions. Basal cell cancer remains the most common skin neoplasm, and simple excision is generally curative. On the other hand, aggressive local growth and metastasis are common features of malignant melanoma, which accounts for 75% of all deaths associated with skin cancer. The primary cause of skin cancer is long exposure to solar ultraviolet radiation (UV-R crossed with the amount of skin pigmentation and family genetics. It is believed that in childhood and adolescence, 80% of UV-R gets absorbed while in the remaining, 20 % gets absorbed later in the lifetime. This suggests that proper and early photoprotection may reduce the risk of subsequent occurrence of skin cancer. Reducing the exposure time to sunlight, using sunscreens and protective textiles are the three ways of UV protection. Most people think that all the clothing will protect them, but it does not provide full sun screening properties. Literature sources claim that only 1/3 of the spring and summer collections tested give off proper UV protection. This is very important during the summer months, when UV index is the highest. Fabric UV protection ability highly depends on large number of factors such as type of fiber, fabric surface, construction, porosity, density, moisture content, type and concentration of dyestuff, fluorescent whitening agents, UV-B protective agents (UV absorbers, as well as nanoparticles, if applied. For all of these reasons, in the present paper, the results of UV protecting ability according to AS/NZS 4399:1996 will be discussed to show that standard clothing materials are not always adequate to prevent effect of UV-R to the human skin; and to suggest the possibilities for its improvement for this purpose enhancing light conversion and scattering. Additionally, the discrepancy in UV protection was investigated in distilled water as well as Adriatic Sea water.

  6. The liver fluke Opisthorchis felineus: biology, epidemiology and carcinogenic potential.

    Science.gov (United States)

    Pakharukova, Mariya Y; Mordvinov, Viatcheslav A

    2016-01-01

    The liver fluke Opisthorchis felineus is a member of the triad of epidemiologically important liver fluke species belonging to the family Opisthorchiidae and the major agent causing opisthorchiasis over a vast territory, covering Russia, Kazakhstan and several European countries. The similarity between the diseases caused by O. felineus and other liver flukes, O. viverrini and Clonorchis sinensis, in clinical manifestations and course suggests that the scenarios of their development and, possibly, complications have much in common. The International Agency for Research on Cancer classified O. viverrini and C. sinensis as group 1 agents and the major factors inducing cholangiocarcinoma in endemic regions. However, a carcinogenic potential of O. felineus is poorly studied. This review characterizes O. felineus, briefs the epidemiological situation in Western Siberia, the world's largest opisthorchiasis focus, and assesses the carcinogenic potential of this liver fluke. The review is based on a comprehensive analysis of the published medical data on opisthorchiasis and its complications in Western Siberia. Results of performed analysis reflect the actual epidemiological situation in opisthorchiasis focus and suggest an association of this disease with bile duct cancer. PMID:26740360

  7. Chromosomal aberrations in lymphocytes predict human cancer independently of exposure to carcinogens. European Study Group on Cytogenetic Biomarkers and Health

    DEFF Research Database (Denmark)

    Bonassi, S; Hagmar, L; Strömberg, U;

    2000-01-01

    in the regression model. The risk for high versus low levels of CAs was similar in subjects heavily exposed to carcinogens and in those who had never, to their knowledge, been exposed to any major carcinogenic agent during their lifetime, supporting the idea that chromosome damage itself is involved in the pathway...... to cancer. The results have important ramifications for the understanding of the role played by sporadic chromosome damage for the origin of neoplasia-associated CAs....

  8. Appraisal of alternative skin model for the study of epidermal restoration following exposure to various environmental stress agents: ionising radiation and UV B

    International Nuclear Information System (INIS)

    Human skin is a major target tissue for ionising radiation (IR) and UV B. We developed a skin explant model and used 2 types of keratinocytes to study survival and oxidative stress induced by these radiations. We examined oxidative damages by measuring R.O.S. produced and cellular anti-oxidant defenses induced. We observed into skin exposed to IR a modulation of genes expression implied in the control of oxidative stress, confirmed by the decrease of catalase, glutathione peroxidase and superoxide dismutase enzymatic activities. The imbalance observed between anti- and pro-apoptotic genes expression shows that keratinocytes apoptosis may be partly dependent on radio-induced R.O.S. production. We showed the difference of radiosensitivity between N.H.E.K. and Ha Ca.T., which may be linked to their differential oxidative responses. In addition, during re-epithelialising, we demonstrated that activated N.H.E.K. after IR express keratin 6, release pro-inflammatory cytokines and proliferate, without modification of their differentiation. Treatment of N.H.E.K. with geranyl geranylacetone (G.G.A.) has a beneficial effect on their radio-induced activation by increasing IL-1 release, their migration in scrapped area and their survival. G.G.A. has an anti apoptotic ability (induction of Hsp70- caspase-3 pathway) and migratory properties (P38/RhoA activation) on N.H.E.K., but after IR, only caspase-3 pathway is induced. This work thus contributes to the understanding of cutaneous damages after IR and G.G.A. mechanism of action which accelerates re-epithelialising. (author)

  9. Carcinogenic effects of benzene: Cesare Maltoni's contributions.

    Science.gov (United States)

    Mehlman, Myron A

    2002-12-01

    Cesare Maltoni's contributions to understanding, identifying, and characterizing widely used commercial chemicals in experimental animals are among the most important methods developed in the history of toxicology and serve to protect working men and women, the general population, and our environment from hazardous substances. Maltoni developed experimental methods that have reached the "platinum standard" for protection of public health. Benzene was among the 400 or more chemicals that Maltoni and his associates tested for carcinogenicity. In 1976, Maltoni reported that benzene is a potent experimental carcinogen. Maltoni's experiments clearly demonstrated that benzene is carcinogenic in Sprague-Dawley rats, Wistar rats, Swiss mice, and RF/J mice when administered by inhalation or ingestion. Benzene caused carcinomas of the Zymbal gland, oral cavity, nasal cavities; cancers of the skin, forestomach, mammary glands, and lungs; angiosarcomas and hepatomas of the liver; and hemolymphoreticular cancers. Thus, benzene was shown to be a multipotential carcinogen that produced cancers in several species of animals by various routes of administration. On November 2, 1977, Chemical Week reported that Maltoni provided a "bombshell" when he demonstrated the "first direct link" between benzene and cancer. In this paper, I shall summarize early experiments and human studies and reports; Maltoni's experimental contribution to understanding the carcinogenicity of benzene in humans and animals; earlier knowledge concerning benzene toxicity; and benzene standards and permissible exposure levels.

  10. Small Molecules Target Carcinogenic Proteins

    Science.gov (United States)

    Gradinaru, Claudiu

    2009-03-01

    An ingenious cellular mechanism of effecting protein localization is prenylation: the covalent attachment of a hydrophobic prenyl group to a protein that facilitates protein association with cell membranes. Fluorescence microscopy was used to investigate whether the oncogenic Stat3 protein can undergo artificial prenylation via high-affinity prenylated small-molecule binding agents and thus be rendered inactive by localization at the plasma membrane instead of nucleus. The measurements were performed on a home-built instrument capable of recording simultaneously several optical parameters (lifetime, polarization, color, etc) and with single-molecule sensitivity. A pH-invariant fluorescein derivative with double moiety was designed to bridge a prenyl group and a small peptide that binds Stat3 with high affinity. Confocal fluorescence images show effective localization of the ligand to the membrane of liposomes. Stat3 predominantly localizes at the membrane only in the presence of the prenylated ligand. Single-molecule FRET (fluorescence resonance energy transfer) between donor-labeled prenylated agents and acceptor-labeled, surface tethered Stat3 protein is used to determine the dynamic heterogeneity of the protein-ligand interaction and follow individual binding-unbinding events in real time. The data indicates that molecules can effect protein localization, validating a therapeutic design that influences protein activity via induced localization.

  11. Evaluation of damage to DNA induced by UV-C radiation and chemical agents using electrochemical biosensor based on low molecular weight DNA and screen-printed carbon electrode

    International Nuclear Information System (INIS)

    Highlights: ► Evaluation of damage to DNA induced by UV-C radiation and chemical agents. ► Utilization of an electrochemical DNA biosensor based on low molecular weight DNA. ► Utilization of screen-printed carbon electrode as an electrical transducer. ► Complex detection of double-stranded DNA damage. - Abstract: There is great interest and need to detect and evaluate damage to DNA by environmental factors. In the present paper, simple electrochemical DNA biosensors composed of commercially available screen-printed carbon electrode (SPCE) and low molecular weight double-stranded DNA (dsDNA) recognition layer are reported and applied to the detection of damage to DNA by UV-C radiation and reactive oxygen species produced by the Fenton type reaction in model as well as mineral water samples with additives. Complex DNA biosensor response is based on square-wave voltammetric intrinsic signal of the guanine moiety as well as that of the intercalative indicator thioridazine, cyclic voltammetric response of the [Fe(CN)6]3−/4− indicator in solution and on electrochemical impedance spectroscopy when the measurements can be performed in the same solution. For the last two types of measurements, the biosensor was also used with an interface between the SPCE and DNA formed by a composite of carboxylated single-walled carbon nanotubes and chitosan to enhance the transducer conductivity. Individual electrochemical/electrical signals depend on the time of biosensor incubation in a cleavage medium and their profiles characterize process of deep DNA degradation.

  12. Mutagenicity, carcinogenicity and teratogenicity of beryllium.

    Science.gov (United States)

    Léonard, A; Lauwerys, R

    1987-07-01

    The carcinogenicity of a number of beryllium compounds has been confirmed in experiments on laboratory animals and this metal has to be treated as a possible carcinogenic threat to man. These carcinogenic properties are associated with mutagenic activity as shown by the results of short-term tests performed in vitro with beryllium chloride and beryllium sulfate. These soluble beryllium compounds can produce some infidelity of in vitro synthesis, forward gene mutations in microorganisms and in mammalian cells. They are also able to induce cell transformation. In addition to the positive results obtained in several short-term assays beryllium compounds have been found to bind to nucleoproteins, to inhibit certain enzymes needed for DNA synthesis, to bind nucleic acids to cell membranes and to inhibit microtubule polymerization. The teratogenicity of beryllium salts is relatively unknown and needs additional investigation.

  13. In Silico Methods for Carcinogenicity Assessment.

    Science.gov (United States)

    Golbamaki, Azadi; Benfenati, Emilio

    2016-01-01

    Screening compounds for potential carcinogenicity is of major importance for prevention of environmentally induced cancers. A large sequence of alternative predictive models, ranging from short-term biological assays (e.g. mutagenicity tests) to theoretical models, have been attempted in this field. Theoretical approaches such as (Q)SAR are highly desirable for identifying carcinogens, since they actively promote the replacement, reduction, and refinement of animal tests. This chapter reports and describes some of the most noted (Q)SAR models based on the human expert knowledge and statistically approach, aiming at predicting the carcinogenicity of chemicals. Additionally, the performance of the selected models has been evaluated and the results are interpreted in details by applying these prediction models to some pharmaceutical molecules.

  14. Occupational exposures to carcinogens in developing countries.

    Science.gov (United States)

    Pearce, N; Matos, E; Boffetta, P; Kogevinas, M; Vainio, H

    1994-09-01

    There have been very few studies of exposure to occupational carcinogens in developing countries, and even fewer studies of the health consequences of such exposures. However, all industrial chemicals, occupations and industrial processes classified by the International Agency for Research on Cancer (IARC) as Group 1 or Group 2A (carcinogenic or possibly carcinogenic to humans) have been described in developing countries, and there is growing concern that the health impact of many chemicals used in the developing world has been underestimated. In all regions a very large workforce is employed in the construction industry, in which substantial exposure to asbestos may occur, and there has been a rapid increase in production in countries such as Brazil and India. There is, for instance, a similar pattern for tyre production with a large increase in production in developing countries in the 1980s. Thus, the number of workers in industries entailing a carcinogenic risk is increasing in developing countries, partly as a result of the transfer of hazardous industry from industrialized countries. There is much that could be achieved in the prevention of occupational cancer in developing countries, and there have been a number of successful initiatives. However, the greatest progress in the prevention of occupational cancer in developing countries is most likely to come from political and economic changes. PMID:7847748

  15. Carcinogenic compounds in alcoholic beverages: an update.

    Science.gov (United States)

    Pflaum, Tabea; Hausler, Thomas; Baumung, Claudia; Ackermann, Svenja; Kuballa, Thomas; Rehm, Jürgen; Lachenmeier, Dirk W

    2016-10-01

    The consumption of alcoholic beverages has been classified as carcinogenic to humans by the International Agency for Research on Cancer (IARC) since 1988. More recently, in 2010, ethanol as the major constituent of alcoholic beverages and its metabolite acetaldehyde were also classified as carcinogenic to humans. Alcoholic beverages as multi-component mixtures may additionally contain further known or suspected human carcinogens as constituent or contaminant. This review will discuss the occurrence and toxicology of eighteen carcinogenic compounds (acetaldehyde, acrylamide, aflatoxins, arsenic, benzene, cadmium, ethanol, ethyl carbamate, formaldehyde, furan, glyphosate, lead, 3-MCPD, 4-methylimidazole, N-nitrosodimethylamine, pulegone, ochratoxin A, safrole) occurring in alcoholic beverages as identified based on monograph reviews by the IARC. For most of the compounds of alcoholic beverages, quantitative risk assessment provided evidence for only a very low risk (such as margins of exposure above 10,000). The highest risk was found for ethanol, which may reach exposures in ranges known to increase the cancer risk even at moderate drinking (margin of exposure around 1). Other constituents that could pose a risk to the drinker were inorganic lead, arsenic, acetaldehyde, cadmium and ethyl carbamate, for most of which mitigation by good manufacturing practices is possible. Nevertheless, due to the major effect of ethanol, the cancer burden due to alcohol consumption can only be reduced by reducing alcohol consumption in general or by lowering the alcoholic strength of beverages.

  16. UV Light Induces Dedoping of Polyaniline

    Directory of Open Access Journals (Sweden)

    Yuki Kaitsuka

    2016-01-01

    Full Text Available UV (Ultra-Violet light-driven change in optical absorption of polyaniline (PANI is reported. Irradiation of UV light to PANI/camphor sulfonic acid prepared by electrochemical polymerization allows dedoping of the PANI. Especially, UV light irradiation in the presence of a radical trap agent effectively reduces (dedoping the PANI. The result in this study is quite simple; however, this may be a first report for light-induced dedoping (color change of a conductive polymer.

  17. Carcinogens formed when Meat is Cooked

    Energy Technology Data Exchange (ETDEWEB)

    Felton, J S; Salmon, C P; Knize, M G

    2003-05-30

    Diet has been associated with varying cancer rates in human populations for many years, yet the causes of the observed variation in cancer patterns have not been adequately explained (Wynder et al. 1977). Along with the effect of diet on human cancer incidence is the strong evidence that mutations are the initiating events in the cancer process (Vogelstein et al. 1992). Foods, when heated, are a good source of genotoxic carcinogens that very likely are a cause for some of these events(Doll et al. 1981). These carcinogens fall into two chemical classes: heterocyclic aromatic amines (HAA) and polycyclic aromatic hydrocarbons (PAH). There is ample evidence that many of these compounds are complete carcinogens in rodents(El-Bayoumy et al. 1995; Ohgaki et al. 1991). Heterocyclic aromatic amines are among the most potent mutagenic substances ever tested in the Ames/Salmonella mutagenicity test (Wakabayashi et al. 1992). Both classes of carcinogen cause tumors in rodents at multiple sites, (El-Bayoumy et al. 1995; Ohgaki et al. 1991) many of which are common tumor sites in people on a Western diet. An HAA, PhIP (2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine), and a PAH, B[a]P (benzo[a]pyrene), of comparable carcinogenic potency caused mammary gland tumors in a feeding study in female rats (El-Bayoumy et al. 1995). In addition, PhIP has recently been shown to cause carcinomas in the prostate of the male rat (Shirai et al. 1997). Complementing the rodent cancer studies are numerous human case-control and prospective studies suggesting a relationship between overheated beef, chicken, and lamb, and cancer of the colon, breast, prostate, and stomach (Sinha et al. 1999; Ward et al. 1997; Zheng et al. 1998).

  18. The comet assay with multiple mouse organs: comparison of comet assay results and carcinogenicity with 208 chemicals selected from the IARC monographs and U.S. NTP Carcinogenicity Database.

    Science.gov (United States)

    Sasaki, Y F; Sekihashi, K; Izumiyama, F; Nishidate, E; Saga, A; Ishida, K; Tsuda, S

    2000-11-01

    The comet assay is a microgel electrophoresis technique for detecting DNA damage at the level of the single cell. When this technique is applied to detect genotoxicity in experimental animals, the most important advantage is that DNA lesions can be measured in any organ, regardless of the extent of mitotic activity. The purpose of this article is to summarize the in vivo genotoxicity in eight organs of the mouse of 208 chemicals selected from International Agency for Research on Cancer (IARC) Groups 1, 2A, 2B, 3, and 4, and from the U.S. National Toxicology Program (NTP) Carcinogenicity Database, and to discuss the utility of the comet assay in genetic toxicology. Alkylating agents, amides, aromatic amines, azo compounds, cyclic nitro compounds, hydrazines, halides having reactive halogens, and polycyclic aromatic hydrocarbons were chemicals showing high positive effects in this assay. The responses detected reflected the ability of this assay to detect the fragmentation of DNA molecules produced by DNA single strand breaks induced chemically and those derived from alkali-labile sites developed from alkylated bases and bulky base adducts. The mouse or rat organs exhibiting increased levels of DNA damage were not necessarily the target organs for carcinogenicity. It was rare, in contrast, for the target organs not to show DNA damage. Therefore, organ-specific genotoxicity was necessary but not sufficient for the prediction of organ-specific carcinogenicity. It would be expected that DNA crosslinkers would be difficult to detect by this assay, because of the resulting inhibition of DNA unwinding. The proportion of 10 DNA crosslinkers that was positive, however, was high in the gastrointestinal mucosa, stomach, and colon, but less than 50% in the liver and lung. It was interesting that the genotoxicity of DNA crosslinkers could be detected in the gastrointestinal organs even though the agents were administered intraperitoneally. Chemical carcinogens can be classified

  19. Detection of genotoxic and non-genotoxic carcinogens in Xpc−/−p53+/− mice

    International Nuclear Information System (INIS)

    An accurate assessment of the carcinogenic potential of chemicals and pharmaceutical drugs is essential to protect humans and the environment. Therefore, substances are extensively tested before they are marketed to the public. Currently, the rodent two-year bioassay is still routinely used to assess the carcinogenic potential of substances. However, over time it has become clear that this assay yields false positive results and also has several economic and ethical drawbacks including the use of large numbers of animals, the long duration, and the high cost. The need for a suitable alternative assay is therefore high. Previously, we have proposed the Xpa*p53 mouse model as a very suitable alternative to the two-year bioassay. We now show that the Xpc*p53 mouse model preserves all the beneficial traits of the Xpa*p53 model for sub-chronic carcinogen identification and can identify both genotoxic and non-genotoxic carcinogens. Moreover, Xpc*p53 mice appear to be more responsive than Xpa*p53 mice towards several genotoxic and non-genotoxic carcinogens. Furthermore, Xpc*p53 mice are far less sensitive than Xpa*p53 mice for the toxic activity of DNA damaging agents and as such clearly respond in a similar way as wild type mice do. These advantageous traits of the Xpc*p53 model make it a better alternative for in vivo carcinogen testing than Xpa*p53. This pilot study suggests that Xpc*p53 mice are suited for routine sub-chronic testing of both genotoxic and non-genotoxic carcinogens and as such represent a suitable alternative to possibly replace the murine life time cancer bioassay. Highlights: ► The Xpc*p53 mouse model is able to identify genotoxic and non-genotoxic carcinogens. ► Time, animals and cost can be significantly reduced compared to the 2-year bioassay. ► Xpc*p53 mice are more advantageous for carcinogen identification than Xpa*p53 mice. ► Xpc*p53 mice exhibit a wild type response upon exposure to genotoxicants.

  20. Predictions for the outcome of rodent carcinogenicity bioassays: identification of trans-species carcinogens and noncarcinogens.

    OpenAIRE

    Tennant, R W; Spalding, J.

    1996-01-01

    Thirty chemicals or substances currently undergoing long-term carcinogenicity bioassays in rodents have been used in a project to further evaluate methods and information that may have the capability of predicting potential carcinogens. In our predictions the principal information used includes structural alerts and in vitro test results for Salmonella mutagenicity, relative subchronic toxicity, and the sites and types of pathology found in subchronic (90-day) studies. This group of chemicals...

  1. Emissions and air exposure of carcinogens and co-carcinogens in four Nordic countries

    DEFF Research Database (Denmark)

    Fauser, Patrik; Plejdrup, Marlene Schmidt; Ketzel, Matthias;

    . A list of carcinogenic andco-carcinogenic pollutants (particles, heavy metals and organic compounds) emittedfrom energy production, industrial activities, road transport, navigation, agriculture, residential heating and product use was compiled. Pollutant emissions levels for 2010and trends for 1990...... sources, traffic and residential wood combustion. An overview of local studies on exposure for cities or communities with emphasis on wood combustion and traffic and a discussion of existing epidemiological studies on cancer and environment were given...

  2. EVALUATION OF THE POTENTIAL CARCINOGENICITY OF COKE OVEN EMISSIONS

    Science.gov (United States)

    Coke oven emissions are known human carcinogens, classified as weight-of-evidence Group A under the EPA Guidelines for Carcinogen Risk Assessment (U.S. EPA, 1986a). vidence on potential carcinogenicity from animal studies is "Sufficient,". and the evidence rom human studies is "S...

  3. Health protection: Toxic agent and radiation control.

    Science.gov (United States)

    1983-01-01

    It is estimated that of the four million chemical compounds which have been synthesized or isolated from natural materials, more than 55,000 are produced commercially. Approximately 1,000 new compounds are introduced annually; pesticide formulations alone contain about 1,500 active chemical ingredients. Diagnostic x-rays are used extensively in medicine and dentistry. Over 2,000 chemicals are suspected carcinogens in laboratory animals--epidemiologic evidence suggests that 26 of these chemicals and/or industrial processes are carcinogenic in humans. More than 20 agents are known to be associated with birth defects in humans; 47 atmospheric contaminants have been identified in animal studies as recognized carcinogens and 128 as mutagens; and, of the 765 contaminants identified in drinking water, 12 were recognized carcinogens, 31 suspected carcinogens, and 59 mutagens. Radiation has known carcinogenic and genetic effects at significant levels of exposure. Problems with toxic agents and radiation sources occur not only in industry, but also in medical and dental care (x-rays and drugs), agriculture (pesticides and herbicides), Government activities (biological and chemical agents), consumer products (incorrect use of consumer products which contain toxic substances), and natural sources (fungal products).

  4. STAT3 as a chemoprevention target in carcinogen-induced head and neck squamous cell carcinoma.

    OpenAIRE

    Peyser, ND; Wang, L.; Zeng, Y.; Acquafondata, M.; Freilino, ML; Li, H.; M. Sen; Gooding, WE; Satake, M; Wang, Z.; Johnson; Grandis, JR

    2016-01-01

    Head and neck squamous cell carcinoma (HNSCC) is a frequently fatal disease due in large part to a high rate of second primary tumor (SPT) formation. The 4-nitroquinoline 1-oxide (4-NQO) mouse model of oral carcinogenesis provides a robust system in which to study chemopreventive agents in the context of chemically-induced HNSCC tumors. Signal transducer and activator of transcription 3 (STAT3) is a potent oncogene that is hyperactivated by tyrosine phosphorylation early in HNSCC carcinogenes...

  5. Modulation of immune function by UV radiation

    International Nuclear Information System (INIS)

    In addition to its carcinogenic activity, ultraviolet (UV) radiation is capable of modifying certain immunologic reactions. Immunologic alterations induced in mice by UV radiation include both local and distant effects. Local alterations result from a direct effect of UV radiation on an immune reaction that takes place at the site of irradiation. Distant alterations are those in which exposure of skin to UV radiation at one site modifies an immune reaction occurring at a distant, unexposed site. Based on recent studies, the authors propose that there may be two types of distant alterations. One is nonspecific, may be due to accumulation of leukocytes at the site of UV-induced inflammation, and is exemplified by the suppression of delayed hypersensitivity and local graft-versus-host (GVH) reactions. The second may result from DNA damage, may involve a soluble mediator, and is manifested by the systemic suppression of contact hypersensitivity and the formation of antigen-specific suppressor T lymphocytes. These immunologic effects of exposure to UV radiation may be important in the pathogenesis of skin cancer and other cutaneous diseases

  6. [Carcinogenic activity of the pesticide propoxur].

    Science.gov (United States)

    Pylev, L N; Vasil'eva, L A; Smirnova, O V; Khrustalev, S A; Trukhina, G M

    2010-01-01

    Wistar rats were fed propoxur in their diet at 0, 500, 3000, and 8000 ppm during throughout their life. The number of tumors was equal in the control and experimental groups. These were hemoblastoses and breast and uterine tumors. All tumors occurred spontaneously in the rats. A few experimental animals were found to have bladder epithelial hyperplasia that might be pretumorous; however, no bladder tumors were detected. It is concluded that the investigations revealed no carcinogenic activity of propoxur.

  7. RADON AND CARCINOGENIC RISK IN MOSCOW

    Directory of Open Access Journals (Sweden)

    S. M. Golovanev

    2015-01-01

    Full Text Available Objective: comparative evaluation of carcinogenic risk inMoscowfrom radon in indoor and atmospheric pollutants.Materials and methods: the lung cancer incidence in Moscow; radiation-hygienic passport of the territory; .U.S. EPA estimated average age at all and radon induced deaths, years of life lost; Report of UNSCEAR 2006 and WHO handbook on indoor radon, 2009. Trend analysis of incidence; evaluation of the excess relative risk; assessment of ratio radon-induced population risk and published values оf total population carcinogenic risk from chemical carcinogens.Results: it is shown that the 304 cases of lung cancer per year (1. 85 10-3 on average from 2006 to 2011 (21280diseases for 70 years in addition to background level induced by radon; the differences in average trends of all lungcancer incidence in the districts can exceed 25%.Conclusion. The potential of risk reduction by measures of mitigation radon concentration exceeds 5 times the cost efficiency to reduce emissions from vehicles and can reduce cancer incidence, on average 236 cases per year; population risk 16520 cases over 70 years or save not less than 2832 person-years of life per year. The annual effect of reducing losses from not-survival of 12 years as a result of radon-induced lung cancer deaths exceeds 14160000 dollars. The evaluating of the carcinogenic risk from radon in accordance with the definition of population risk increases the predictive evaluation of the effectiveness of preventive measures more than twice.

  8. The multitude and diversity of environmental carcinogens.

    OpenAIRE

    Belpomme, Dominique; Irigaray, Philippe; Hardell, Lennart; Clapp, Richard; Montagnier, Luc; Epstein, Slava; Sasco, Annie

    2007-01-01

    We have recently proposed that lifestyle-related factors, screening and aging cannot fully account for the present overall growing incidence of cancer. In order to propose the concept that in addition to lifestyle related factors, exogenous environmental factors may play a more important role in carcinogenesis than it is expected, and may therefore account for the growing incidence of cancer, we overview herein environmental factors, rated as certainly or potentially carcinogenic by the Inter...

  9. Temporal aspects of tumorigenic response to individual and mixed carcinogens. Progress report, October 1, 1978-September 30, 1979

    International Nuclear Information System (INIS)

    The research proposed here is designed to obtain a better understanding of the temporal kinetics of tumor induction when one or more carcinogens are present simultaneously or sequentially for prolonged periods of time. Studies done to date under this contract have shown that carcinogenesis in mouse skin by polycyclic aromatic hydrocarbon carcinogens is consistent with the induction of dependent and autonomous cell transformations by the carcinogen followed by the conversion of autonomous tumor cells into malignancies at a rate which is determined by the level of carcinogen exposure. Dependent cell transformations remain latent in the skin unless expressed by a promoting agent. Dependent neoplasia appears to follow one-hit kinetics while malignancy is a multihit endpoint. Dose-related and time-related aspects of tumor induction are separable in the initiation-promotion system of mouse skin which along with rat skin and hamster lung is being used as a model for testing hypotheses. Results to date provide the basis for a new interpretation of the linear non-threshold extrapolation model. The broad aim of the study is to provide a basis or rationale for estimating risks associated with prolonged exposures to carcinogens found in the environment and to predict how different tissues and species respond to the carcinogens, promoters, and cocarcinogens

  10. Temporal aspects of tumorigenic response to individual and mixed carcinogens. Progress report, October 1, 1978-September 30, 1979

    Energy Technology Data Exchange (ETDEWEB)

    Albert, R.E.; Burns, F.J.; Altshuler, B.

    1979-06-01

    The research proposed here is designed to obtain a better understanding of the temporal kinetics of tumor induction when one or more carcinogens are present simultaneously or sequentially for prolonged periods of time. Studies done to date under this contract have shown that carcinogenesis in mouse skin by polycyclic aromatic hydrocarbon carcinogens is consistent with the induction of dependent and autonomous cell transformations by the carcinogen followed by the conversion of autonomous tumor cells into malignancies at a rate which is determined by the level of carcinogen exposure. Dependent cell transformations remain latent in the skin unless expressed by a promoting agent. Dependent neoplasia appears to follow one-hit kinetics while malignancy is a multihit endpoint. Dose-related and time-related aspects of tumor induction are separable in the initiation-promotion system of mouse skin which along with rat skin and hamster lung is being used as a model for testing hypotheses. Results to date provide the basis for a new interpretation of the linear non-threshold extrapolation model. The broad aim of the study is to provide a basis or rationale for estimating risks associated with prolonged exposures to carcinogens found in the environment and to predict how different tissues and species respond to the carcinogens, promoters, and cocarcinogens.

  11. The evolving definition of carcinogenic human papillomavirus

    Directory of Open Access Journals (Sweden)

    Castle Philip E

    2009-05-01

    Full Text Available Abstract Thirteen human papillomavirus (HPV genotypes have been judged to be carcinogenic or probably carcinogenic, and the cause of virtually all cervical cancer worldwide. Other HPV genotypes could possibly be involved. Although the inclusion of possibly carcinogenic HPV genotypes may hurt test specificity, it may indirectly increase the reassurance following a negative HPV test (i.e. the negative predictive value of an HPV test for cervical precancer and cancer. The future of cervical cancer screening in low-resource setting, however, may include once-in-a-lifetime, low-cost and rapid HPV testing. However, the tradeoff of more false positives for greater reassurance may not be acceptable if the local infrastructure cannot manage the screen positives. Now is the time for the community of scientists, doctors, and public health advocates to use the data presented at the 100th International Agency for Research on Cancer monograph meeting to rationally decide the target HPV genotypes for the next generation of HPV tests for use in high-resource and low-resource settings. The implications of including possibly HPV genotypes on HPV test performance, also for guidance on the use of these tests for cervical cancer prevention programs, are discussed.

  12. Impact and compliance: OSHA Carcinogen Policy

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, A.F. Jr.; Crowder, C.; Wisniewski, S.; Russell, T.; Senn, K.

    1980-06-26

    This document provides an examination of various aspects of the Occupational Safety and Health Administration (OSHA)Carcinogen Policy. To satisfy the dimensions of the Policy's broad, general nature, a two-fold approach was taken. Throughout, the focus is on the possible effects of the Policy's implementation, but this is first approached as it generally will effect research and compliance activities across broad industry sectors, while specific impacts on DOE are addressed separately. To overview and integrate these approaches, and to provide a quick reference for further information, an outline of information is presented. General or industry-wide applications are addressed both in the Summary and Overview of the Policy (Chapters I and II) and in the discussion of the Model Standard (Chapter V). Also included is a copy of the Policy itself in the General Industry Standards and interpretations Change 10. Sections specifically addressed to the major concerns of DOE and its contractors are a discussion of implications for action regarding the synthetic fuels program, a comparison of the OSHA Model Regulations and the FE OSH Manual Standards for Carcinogens, and finally, a list of known carcinogens in coal gasification/liquefaction. Together, these elements illustrate the broad scope of the policy's impact, which economic and other constraining consequences begin to become visible. Measures to minimize these consequences are a common underlying theme to each of the sections.

  13. IARC Monographs: 40 Years of Evaluating Carcinogenic Hazards to Humans

    Science.gov (United States)

    Blair, Aaron; Vineis, Paolo; Ahrens, Wolfgang; Andersen, Aage; Anto, Josep M.; Armstrong, Bruce K.; Baccarelli, Andrea A.; Beland, Frederick A.; Berrington, Amy; Bertazzi, Pier Alberto; Birnbaum, Linda S.; Brownson, Ross C.; Bucher, John R.; Cantor, Kenneth P.; Cardis, Elisabeth; Cherrie, John W.; Christiani, David C.; Cocco, Pierluigi; Coggon, David; Comba, Pietro; Demers, Paul A.; Dement, John M.; Douwes, Jeroen; Eisen, Ellen A.; Engel, Lawrence S.; Fenske, Richard A.; Fleming, Lora E.; Fletcher, Tony; Fontham, Elizabeth; Forastiere, Francesco; Frentzel-Beyme, Rainer; Fritschi, Lin; Gerin, Michel; Goldberg, Marcel; Grandjean, Philippe; Grimsrud, Tom K.; Gustavsson, Per; Haines, Andy; Hartge, Patricia; Hansen, Johnni; Hauptmann, Michael; Heederik, Dick; Hemminki, Kari; Hemon, Denis; Hertz-Picciotto, Irva; Hoppin, Jane A.; Huff, James; Jarvholm, Bengt; Kang, Daehee; Karagas, Margaret R.; Kjaerheim, Kristina; Kjuus, Helge; Kogevinas, Manolis; Kriebel, David; Kristensen, Petter; Kromhout, Hans; Laden, Francine; Lebailly, Pierre; LeMasters, Grace; Lubin, Jay H.; Lynch, Charles F.; Lynge, Elsebeth; ‘t Mannetje, Andrea; McMichael, Anthony J.; McLaughlin, John R.; Marrett, Loraine; Martuzzi, Marco; Merchant, James A.; Merler, Enzo; Merletti, Franco; Miller, Anthony; Mirer, Franklin E.; Monson, Richard; Nordby, Karl-Cristian; Olshan, Andrew F.; Parent, Marie-Elise; Perera, Frederica P.; Perry, Melissa J.; Pesatori, Angela Cecilia; Pirastu, Roberta; Porta, Miquel; Pukkala, Eero; Rice, Carol; Richardson, David B.; Ritter, Leonard; Ritz, Beate; Ronckers, Cecile M.; Rushton, Lesley; Rusiecki, Jennifer A.; Rusyn, Ivan; Samet, Jonathan M.; Sandler, Dale P.; de Sanjose, Silvia; Schernhammer, Eva; Costantini, Adele Seniori; Seixas, Noah; Shy, Carl; Siemiatycki, Jack; Silverman, Debra T.; Simonato, Lorenzo; Smith, Allan H.; Smith, Martyn T.; Spinelli, John J.; Spitz, Margaret R.; Stallones, Lorann; Stayner, Leslie T.; Steenland, Kyle; Stenzel, Mark; Stewart, Bernard W.; Stewart, Patricia A.; Symanski, Elaine; Terracini, Benedetto; Tolbert, Paige E.; Vainio, Harri; Vena, John; Vermeulen, Roel; Victora, Cesar G.; Ward, Elizabeth M.; Weinberg, Clarice R.; Weisenburger, Dennis; Wesseling, Catharina; Weiderpass, Elisabete; Zahm, Shelia Hoar

    2015-01-01

    Background: Recently, the International Agency for Research on Cancer (IARC) Programme for the Evaluation of Carcinogenic Risks to Humans has been criticized for several of its evaluations, and also for the approach used to perform these evaluations. Some critics have claimed that failures of IARC Working Groups to recognize study weaknesses and biases of Working Group members have led to inappropriate classification of a number of agents as carcinogenic to humans. Objectives: The authors of this Commentary are scientists from various disciplines relevant to the identification and hazard evaluation of human carcinogens. We examined criticisms of the IARC classification process to determine the validity of these concerns. Here, we present the results of that examination, review the history of IARC evaluations, and describe how the IARC evaluations are performed. Discussion: We concluded that these recent criticisms are unconvincing. The procedures employed by IARC to assemble Working Groups of scientists from the various disciplines and the techniques followed to review the literature and perform hazard assessment of various agents provide a balanced evaluation and an appropriate indication of the weight of the evidence. Some disagreement by individual scientists to some evaluations is not evidence of process failure. The review process has been modified over time and will undoubtedly be altered in the future to improve the process. Any process can in theory be improved, and we would support continued review and improvement of the IARC processes. This does not mean, however, that the current procedures are flawed. Conclusions: The IARC Monographs have made, and continue to make, major contributions to the scientific underpinning for societal actions to improve the public’s health. Citation: Pearce N, Blair A, Vineis P, Ahrens W, Andersen A, Anto JM, Armstrong BK, Baccarelli AA, Beland FA, Berrington A, Bertazzi PA, Birnbaum LS, Brownson RC, Bucher JR, Cantor KP

  14. RADON AND CARCINOGENIC RISK IN MOSCOW

    OpenAIRE

    S. M. Golovanev

    2015-01-01

    Objective: comparative evaluation of carcinogenic risk inMoscowfrom radon in indoor and atmospheric pollutants.Materials and methods: the lung cancer incidence in Moscow; radiation-hygienic passport of the territory; .U.S. EPA estimated average age at all and radon induced deaths, years of life lost; Report of UNSCEAR 2006 and WHO handbook on indoor radon, 2009. Trend analysis of incidence; evaluation of the excess relative risk; assessment of ratio radon-induced population risk and published...

  15. Indoor air-assessment: Indoor concentrations of environmental carcinogens

    International Nuclear Information System (INIS)

    In the report, indoor concentration data are presented for the following general categories of air pollutants: radon-222, environmental tobacco smoke (ETS), asbestos, gas phase organic compounds, formaldehyde, polycyclic aromatic hydrocarbons (PAH), pesticides, and inorganic compounds. These pollutants are either known or suspect carcinogens (i.e., radon-222, asbestos) or more complex mixtures or classes of compounds which contain known or suspect carcinogens. Concentration data for individual carcinogenic compounds in complex mixtures are usually far from complete. The data presented for complex mixtures often include compounds which are not carcinogenic or for which data are insufficient to evaluate carcinogenicity. Their inclusion is justified, however, by the possibility that further work may show them to be carcinogens, cocarcinogens, initiators or promotors, or that they may be employed as markers (e.g., nicotine, acrolein) for the estimation of exposure to complex mixtures

  16. Radiation equivalency: A conceptual relationship for indexing the carcinogenic properties of radiation and environmental pollutants

    International Nuclear Information System (INIS)

    A Tier-Two type of bioassay complimentary to the National Cancer Institute whole-animal protocol has been proposed based upon relating the antitumor cell-mediated immune responses induced by the test substance to those immune effects induced by a localized exposure to X-rays, a concept which termed the substance's Radiation Equivalency. The conceptual principle for the Radiation Equivalency entails the hypothesis that a mutagenic/carcinogenic insult results in the development of transformed ''foreign-like'' cells which then initiate their specific recognition by the host's immune system. This immune sensitization can then be quantitated by measuring the increased injury and killing of cultured tumor cells by the now so-called educated peripheral blood lymphoid-cells obtained from the exposed animals. The authors proposed that all carcinogenic agents will interact with their particular organoismal components in a constant fashion to induce such antitumor immune responses, thus permitting the experimental results to be interpreted according to the Law of Mass Action. The findings have been accordingly described in terms of Michaelis-Menton kinetics with specific experimental comparisons in the rate presented between the colon carcinogen, 1,2-dimethylhydrazine (DMH), and the X-irradiation effects upon the localized hypoxic small bowel to obtain a Radiation Equivalency value for the chemical. Similar measurements have also been utilized for the analysis of mutagens/carcinogens present in the urine obtained from DMH-exposed rats such to arrive at its Radiation Equivalency. Previous findings have been summarized together, all of which suggest that the Radiation Equivalency concept may readily serve as a method for indexing the carcinogenic properties of various environmental pollutants

  17. Carcinogenicity/tumour promotion by NDL PCB

    Energy Technology Data Exchange (ETDEWEB)

    Schrenk, D. [Kaiserslautern Univ. (Germany). Food Chemistry and Environmental Toxicology

    2004-09-15

    Polychlorinated biphenyls (PCBs) belong to the group of persistent environmental pollutants exhibiting neurotoxic, teratogenic and tumour-promoting effects in experimental animal models. PCB congeners can be divided into 'dioxinlike' and 'non-dioxinlike' congeners on the basis of their ability to act as aryl hydrocarbon receptor (AhR) agonists. Like the most toxic dioxin congener 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) 'dioxinlike' PCBs bind to the AhR and show characteristic effects on the expression of AhR-regulated genes including the induction of cytochrome P450 (CYP) 1A1. On the other hand, 'non-dioxinlike' PCB congeners have a lower or no binding affinity to the AhR, but exhibit a 'phenobarbital-type' induction of CYP 2B1/2 activity. A carcinogenic potential of PCBs has been demonstrated with technical mixtures such as Aroclors or Clophens. In these studies the liver and the thyroid gland were found to be the principal target organs of PCB-mediated carcinogenesis in rodents. No studies have been published, however, on the carcinogenicity of individual congeners. In two-stage initiation-promotion protocols in rats, both technical mixtures and individual 'dioxinlike' and 'non-dioxinlike' congeners were reported to act as liver tumour promoters.

  18. CORAL software: prediction of carcinogenicity of drugs by means of the Monte Carlo method.

    Science.gov (United States)

    Toropova, Alla P; Toropov, Andrey A

    2014-02-14

    Methodology of building up and validation of models for carcinogenic potentials of drugs by means of the CORAL software is described. The QSAR analysis by the CORAL software includes three phases: (i) definition of preferable parameters for the optimization procedure that gives maximal correlation coefficient between endpoint and an optimal descriptor that is calculated with so-called correlation weights of various molecular features; (ii) detection of molecular features with stable positive correlation weights or vice versa stable negative correlation weights (molecular features which are characterized by solely positive or solely negative correlation weights obtained for several starts of the Monte Carlo optimization are a basis for mechanistic interpretations of the model); and (iii) building up the model that is satisfactory from point of view of reliable probabilistic criteria and OECD principles. The methodology is demonstrated for the case of carcinogenicity of a large set (n = 1464) of organic compounds which are potential or actual pharmaceutical agents.

  19. Mechanisms underlying UV-induced immune suppression

    Energy Technology Data Exchange (ETDEWEB)

    Ullrich, Stephen E. [Department of Immunology, University of Texas, MD Anderson Cancer Center, South Campus Research Building 1, 7455 Fannin St., P.O. Box 301402, Houston, TX 77030-1903 (United States)]. E-mail: sullrich@mdanderson.org

    2005-04-01

    Skin cancer is the most prevalent form of human neoplasia. Estimates suggest that in excess of one million new cases of skin cancer will be diagnosed this year alone in the United States (www.cancer.org/statistics). Fortunately, because of their highly visible location, skin cancers are more rapidly diagnosed and more easily treated than other types of cancer. Be that as it may, approximately 10,000 Americans a year die from skin cancer. The cost of treating non-melanoma skin cancer is estimated to be in excess of US$ 650 million a year [J.G. Chen, A.B. Fleischer, E.D. Smith, C. Kancler, N.D. Goldman, P.M. Williford, S.R. Feldman, Cost of non-melanoma skin cancer treatment in the United States, Dermatol. Surg. 27 (2001) 1035-1038], and when melanoma is included, the estimated cost of treating skin cancer in the United States is estimated to rise to US$ 2.9 billion annually (www.cancer.org/statistics). Because the morbidity and mortality associated with skin cancer is a major public health problem, it is important to understand the mechanisms underlying skin cancer development. The primary cause of skin cancer is the ultraviolet (UV) radiation found in sunlight. In addition to its carcinogenic potential, UV radiation is also immune suppressive. In fact, data from studies with both experimental animals and biopsy proven skin cancer patients suggest that there is an association between the immune suppressive effects of UV radiation and its carcinogenic potential. The focus of this manuscript will be to review the mechanisms underlying the induction of immune suppression following UV exposure. Particular attention will be directed to the role of soluble mediators in activating immune suppression.

  20. Biological effects of mutagenic agents

    International Nuclear Information System (INIS)

    There is an increasing body of evidence that mutagenic agents (biological, chemical and physical) play an important role in the etiology of human diseases. Mutations may occur in the germinal as well as in the somatic cells. Mutations of the germ cells may result on infertility or fertilization of damaged cells, the later leading to abortion or birth of a malformed fetus. Somatic-cells mutations may have various biological effects, depending on the period of the human life at which the mutation occurs. If it occurs during the prenatal life, a teratogenic or carcinogenic effect will be observed. If the somatic cell is damaged during the postnatal life, this will lead to neoplastic transformation. Therefore it is extremely important to know the mutagenic, teratogenic and carcinogenic effects of various biological, chemical and physical agents in order to eliminate them from our environment. (author). 13 refs, 4 figs, 1 tab

  1. Comparison of N-nitrosodiethylamine degradation in water by UV irradiation and UV/O3: Efficiency, product and mechanism

    International Nuclear Information System (INIS)

    N-Nitrosodiethylamine (NDEA) is a member of nitrosamines, which is strong carcinogenic. In order to explore an effective treatment method for NDEA removal from water, sole UV irradiation and UV/O3 were carried out in this study. The removal efficiency, degradation products and pathways were compared between those two processes. Results showed that NDEA removal efficiency achieved 99% within 15 min by both UV and UV/O3. Degradation reaction well followed pseudo-first-order kinetics. Water pH had different effect on NDEA degradation in those two processes. Acidic and neutral conditions were good for NDEA degradation by sole UV irradiation. However, NDEA underwent rapid degradation under various pH conditions in the UV/O3 process. Though the ozone introduction in the UV/O3 process had little effect on NDEA degradation efficiency, it had significant effect on its degradation products and pathways. Methylamine, dimethylamine, ethylamine and diethylamine were observed as aliphatic amine products of NDEA degradation in both two processes. They were assumed to arise due to N-N bond fission under UV irradiation, or due to the reaction of NDEA and hydroxyl radicals in the UV/O3 process.

  2. Comparison of N-nitrosodiethylamine degradation in water by UV irradiation and UV/O3: efficiency, product and mechanism.

    Science.gov (United States)

    Xu, Bingbing; Chen, Zhonglin; Qi, Fei; Ma, Jun; Wu, Fengchang

    2010-07-15

    N-nitrosodiethylamine (NDEA) is a member of nitrosamines, which is strong carcinogenic. In order to explore an effective treatment method for NDEA removal from water, sole UV irradiation and UV/O(3) were carried out in this study. The removal efficiency, degradation products and pathways were compared between those two processes. Results showed that NDEA removal efficiency achieved 99% within 15 min by both UV and UV/O(3). Degradation reaction well followed pseudo-first-order kinetics. Water pH had different effect on NDEA degradation in those two processes. Acidic and neutral conditions were good for NDEA degradation by sole UV irradiation. However, NDEA underwent rapid degradation under various pH conditions in the UV/O(3) process. Though the ozone introduction in the UV/O(3) process had little effect on NDEA degradation efficiency, it had significant effect on its degradation products and pathways. Methylamine, dimethylamine, ethylamine and diethylamine were observed as aliphatic amine products of NDEA degradation in both two processes. They were assumed to arise due to N-N bond fission under UV irradiation, or due to the reaction of NDEA and hydroxyl radicals in the UV/O(3) process.

  3. Researchers exploring faster alternatives to 2-year test for carcinogenicity.

    OpenAIRE

    Schmidt, Charlie

    2006-01-01

    KEYWORDS - CLASSIFICATION: Animals;Animals,Laboratory;biomarkers of exposure & effect: validation;Carcinogenicity Tests;Carcinogens;Female;metabolism;methods;Male;Mice;Pharmaceutical Preparations;Predictive Value of Tests;Prognosis;Rats;standards;Species Specificity;trends;Time Factors;Tumor Markers,Biological;United States;United States Environmental Protection Agency;United States Food and Drug Administration.

  4. Carcinogens in the Workplace: A Scientific, Political and Social Problem

    OpenAIRE

    Atherley, Gordon; Whiting, Robert

    1982-01-01

    Investigation, assessment, and management of carcinogenic risks are not only scientific but also political responsibilities. In Canada, this becomes cumbersome, since local, provincial and federal policies are involved. The process also involves workers and management. This article outlines Canadian legislative experience, the principles involved, the methods of risk assessment, and the classification of carcinogens in the workplace.

  5. Workshop on problem areas associated with developing carcinogen guidelines

    Energy Technology Data Exchange (ETDEWEB)

    1984-06-01

    A workshop was conducted to discuss problem areas associated with developing carcinogen guidelines. Session topics included (1) definition of a carcinogen for regulatory purposes; (2) potency; (3) risk assessment; (4) uncertainties; (5) de minimis quantity; and (6) legal and regulatory issues. Separate abstracts have been prepared for individual papers. (ACR)

  6. Carcinogenic risk of copper gluconate evaluated by a rat medium-term liver carcinogenicity bioassay protocol

    Energy Technology Data Exchange (ETDEWEB)

    Abe, Masayoshi; Usuda, Koji; Hayashi, Seigo; Ogawa, Izumi; Furukawa, Satoshi [Nissan Chemical Industries Limited, Toxicology and Environmental Science Department, Biological Research Laboratories, Saitama (Japan); Igarashi, Maki [Tokyo University of Agriculture, Laboratory of Protection of Body Function, Department of Food and Nutritional Science, Graduate School of Agriculture, Tokyo (Japan); Nakae, Dai [Tokyo University of Agriculture, Laboratory of Protection of Body Function, Department of Food and Nutritional Science, Graduate School of Agriculture, Tokyo (Japan); Tokyo Metropolitan Institute of Public Health, Tokyo (Japan)

    2008-08-15

    Carcinogenic risk and molecular mechanisms underlying the liver tumor-promoting activity of copper gluconate, an additive of functional foods, were investigated using a rat medium-term liver carcinogenicity bioassay protocol (Ito test) and a 2-week short-term administration experiment. In the medium-term liver bioassay, Fischer 344 male rats were given a single i.p. injection of N-nitrosodiethylamine at a dose of 200 mg/kg b.w. as a carcinogenic initiator. Starting 2 weeks thereafter, rats received 0, 10, 300 or 6,000 ppm of copper gluconate in diet for 6 weeks. All rats underwent 2/3 partial hepatectomy at the end of week 3, and all surviving rats were killed at the end of week 8. In the short-term experiment, rats were given 0, 10, 300 or 6,000 ppm of copper gluconate for 2 weeks. Numbers of glutathione S-transferase placental form (GST-P) positive lesions, single GST-P-positive hepatocytes and 8-oxoguanine-positive hepatocytes, and levels of cell proliferation and apoptosis in the liver were significantly increased by 6,000 ppm of copper gluconate in the medium-term liver bioassay. Furthermore, hepatic mRNA expression of genes relating to the metal metabolism, inflammation and apoptosis were elevated by 6,000 ppm of copper gluconate both in the medium-term liver bioassay and the short-term experiments. These results indicate that copper gluconate possesses carcinogenic risk toward the liver at the high dose level, and that oxidative stress and inflammatory and pro-apoptotic signaling statuses may participate in its underlying mechanisms. (orig.)

  7. Lymphocyte reactivity of workers exposed to carcinogenic and non-carcinogenic chemicals.

    OpenAIRE

    Kumar, S.; Taylor, G; Hurst, W; Wilson, P.; Costello, C B

    1981-01-01

    Immunological studies have shown an increased lymphocyte reactivity in patients with early stage bladder cancer and individuals with pre-stage T1 exposed to bladder carcinogens (2-naphthylamine and industrial 1-naphthylamine containing 4-8% 2-naphthylamine) before 1952-that is, those at high risk of developing bladder cancer. Because of the close chemical similarity of Tobias acid (2-naphthylamine-1 sulphonic acid) to 2-naphthylamine, the lymphocytotoxicity of workers exposed to this chemical...

  8. [MATline, a job-exposure matrix for the prevision of exposure to carcinogens: new functions and potential applications].

    Science.gov (United States)

    Falcone, Umberto; Gilardi, Luisella; Santoro, Silvano; Orengia, Manuela; Marighella, Massimo; Coffano, Maria Elena

    2013-01-01

    MATline, the job-exposure matrix for carcinogenic agents, is a data bank free accessible online. It provides data as classification and toxicological properties of carcinogenic agents, and a list of industrial processes with potential exposure to each carcinogen agent, and an up-to-date estimation of the number of activities and workers related to the industrial process on Regional basis. It also lists the target organs for which a causal relationship with the agent has been established. MATline was recently updated with the new classifications introduced by Regulation EC No. 1272/2008 (CLP). The Authorisation List or the Restriction of the Registration, Evaluation, Authorization of Chemicals (REACh) regulation specifically mark chemicals. The matrix is helpful for professionals in the public health sector to identify in advance the potential sources of exposure, and prioritise intervention plans; for occupational physicians to help identifying causes of occupational cancer cases; for health professionals in the private sector to address chemical risks; for company physicians to validate health surveillance plans; for trade unions to independently check formation contents provided to workers potentially exposed to such risks. PMID:23585435

  9. Detection of genotoxic and non-genotoxic carcinogens in Xpc{sup −/−}p53{sup +/−} mice

    Energy Technology Data Exchange (ETDEWEB)

    Melis, Joost P.M. [Laboratory for Health Protection Research, National Institute for Public Health and the Environment (RIVM), Bilthoven (Netherlands); Leiden University Medical Center, Department of Toxicogenetics, Leiden (Netherlands); Speksnijder, Ewoud N. [Leiden University Medical Center, Department of Toxicogenetics, Leiden (Netherlands); Kuiper, Raoul V. [Laboratory for Health Protection Research, National Institute for Public Health and the Environment (RIVM), Bilthoven (Netherlands); Dutch Molecular Pathology Center, Department of Pathobiology, Faculty of Veterinary Medicine, Utrecht University, Utrecht (Netherlands); Salvatori, Daniela C.F. [Leiden University Medical Center, Central Animal Facility, Leiden (Netherlands); Schaap, Mirjam M. [Laboratory for Health Protection Research, National Institute for Public Health and the Environment (RIVM), Bilthoven (Netherlands); Leiden University Medical Center, Department of Toxicogenetics, Leiden (Netherlands); Maas, Saskia [Leiden University Medical Center, Central Animal Facility, Leiden (Netherlands); Robinson, Joke; Verhoef, Aart; Benthem, Jan van; Luijten, Mirjam [Laboratory for Health Protection Research, National Institute for Public Health and the Environment (RIVM), Bilthoven (Netherlands); Steeg, Harry van, E-mail: Harry.van.Steeg@rivm.nl [Laboratory for Health Protection Research, National Institute for Public Health and the Environment (RIVM), Bilthoven (Netherlands); Leiden University Medical Center, Department of Toxicogenetics, Leiden (Netherlands)

    2013-01-15

    An accurate assessment of the carcinogenic potential of chemicals and pharmaceutical drugs is essential to protect humans and the environment. Therefore, substances are extensively tested before they are marketed to the public. Currently, the rodent two-year bioassay is still routinely used to assess the carcinogenic potential of substances. However, over time it has become clear that this assay yields false positive results and also has several economic and ethical drawbacks including the use of large numbers of animals, the long duration, and the high cost. The need for a suitable alternative assay is therefore high. Previously, we have proposed the Xpa*p53 mouse model as a very suitable alternative to the two-year bioassay. We now show that the Xpc*p53 mouse model preserves all the beneficial traits of the Xpa*p53 model for sub-chronic carcinogen identification and can identify both genotoxic and non-genotoxic carcinogens. Moreover, Xpc*p53 mice appear to be more responsive than Xpa*p53 mice towards several genotoxic and non-genotoxic carcinogens. Furthermore, Xpc*p53 mice are far less sensitive than Xpa*p53 mice for the toxic activity of DNA damaging agents and as such clearly respond in a similar way as wild type mice do. These advantageous traits of the Xpc*p53 model make it a better alternative for in vivo carcinogen testing than Xpa*p53. This pilot study suggests that Xpc*p53 mice are suited for routine sub-chronic testing of both genotoxic and non-genotoxic carcinogens and as such represent a suitable alternative to possibly replace the murine life time cancer bioassay. Highlights: ► The Xpc*p53 mouse model is able to identify genotoxic and non-genotoxic carcinogens. ► Time, animals and cost can be significantly reduced compared to the 2-year bioassay. ► Xpc*p53 mice are more advantageous for carcinogen identification than Xpa*p53 mice. ► Xpc*p53 mice exhibit a wild type response upon exposure to genotoxicants.

  10. The Influences of SiO2 Flatting Agent (UV 55C) on the Properties of Epoxidized Soybean Oil Acrylate%SiO2消光剂(UV 55C)对环氧豆油丙烯酸酯性能的影响

    Institute of Scientific and Technical Information of China (English)

    谢慕华; 耿云华

    2002-01-01

    考察了SiO2消光剂(UV 55C)对环氧豆油丙烯酸酯及其涂膜性能的影响.试验结果表明:SiO 2消光剂(UV 55C)的加入,降低了环氧豆油丙烯酸酯的固化速率和其涂膜的光泽度,但提高了其涂膜的硬度、耐磨性和附着力.

  11. Comparison of the oncogenic potential of several chemotherapeutic agents

    International Nuclear Information System (INIS)

    Several chemotherapeutic drugs that have been routinely used in cancer treatment were tested for their carcinogenic potential. Two antitumor antibiotics (adriamycin and vincristine), an alkalating agent (melphalan), 5-azacytidine and the bifunctional agent cis-platinum that mimics alkylating agents and/or binds Oxygen-6 or Nitrogen-7 atoms of quanine were tested. Cell killing and cancer induction was assessed using in vitro transformation system. C3H/10T 1/2 cells, while normally exhibiting contact inhibition, can undergo transformation from normal contact inhibited cells to tumorgenic cells when exposed to chemical carcinogens. These cells have been used in the past by this laboratory to study oncogenic transformation of cells exposed to ionizing radiation and electron affinic compounds that sensitize hypoxic cells to x-rays. The endpoints of cell killing and oncogenic transformation presented here give an estimate of the carcinogenic potential of these agents

  12. UV Index Widget

    Data.gov (United States)

    U.S. Environmental Protection Agency — The UV Index Widget displays the ultraviolet (UV) Index providing a daily forecast of the expected risk of overexposure to the sun for a user-specified area of...

  13. Carcinogen-specific mutations in preferred Ras-Raf pathway oncogenes directed by strand bias.

    Science.gov (United States)

    Keller, Ross R; Gestl, Shelley A; Lu, Amy Q; Hoke, Alicia; Feith, David J; Gunther, Edward J

    2016-08-01

    Carcinogen exposures inscribe mutation patterns on cancer genomes and sometimes bias the acquisition of driver mutations toward preferred oncogenes, potentially dictating sensitivity to targeted agents. Whether and how carcinogen-specific mutation patterns direct activation of preferred oncogenes remains poorly understood. Here, mouse models of breast cancer were exploited to uncover a mechanistic link between strand-biased mutagenesis and oncogene preference. When chemical carcinogens were employed during Wnt1-initiated mammary tumorigenesis, exposure to either 7,12-dimethylbenz(a)anthracene (DMBA) or N-ethyl-N-nitrosourea (ENU) dramatically accelerated tumor onset. Mammary tumors that followed DMBA exposure nearly always activated the Ras pathway via somatic Hras(CAA61CTA) mutations. Surprisingly, mammary tumors that followed ENU exposure typically lacked Hras mutations, and instead activated the Ras pathway downstream via Braf(GTG636GAG) mutations. Hras(CAA61CTA) mutations involve an A-to-T change on the sense strand, whereas Braf(GTG636GAG) mutations involve an inverse T-to-A change, suggesting that strand-biased mutagenesis may determine oncogene preference. To examine this possibility further, we turned to an alternative Wnt-driven tumor model in which carcinogen exposures augment a latent mammary tumor predisposition in Apc(min) mice. DMBA and ENU each accelerated mammary tumor onset in Apc(min) mice by introducing somatic, "second-hit" Apc mutations. Consistent with our strand bias model, DMBA and ENU generated strikingly distinct Apc mutation patterns, including stringently strand-inverse mutation signatures at A:T sites. Crucially, these contrasting signatures precisely match those proposed to confer bias toward Hras(CAA61CTA) versus Braf(GTG636GAG) mutations in the original tumor sets. Our findings highlight a novel mechanism whereby exposure history acts through strand-biased mutagenesis to specify activation of preferred oncogenes. PMID:27207659

  14. UV missile plume signatures

    NARCIS (Netherlands)

    Neele, F.P.; Schleijpen, H.M.A.

    2002-01-01

    As a result of the deployment of UV missile warning systems, recent years have seen an increasing interest in threat assessment in the UV band. Unfortunately, due to the different nature of the physical processes that are needed to describe a missile signature in the UV, available codes for the IR c

  15. Identification and monitoring of non-radiological carcinogens

    International Nuclear Information System (INIS)

    This study examines the feasibility of identifying and monitoring occupational exposures to non-radiological carcinogens in the workplace at Canadian nuclear establishments (Whiteshell Laboratories, Pickering Nuclear Generating Station, Cameco Limited and Canadian General Electric Company Limited). Recent epidemiological studies recommended that potential confounding factors of a non-radiological nature be identified and analyzed, particularly non-radiological carcinogens that may be present in the workplace at nuclear facilities. The feasibility of identifying and measuring occupational exposures to non-radiological carcinogens in Canadian nuclear facilities is examined. Also, the report describes the problem of chemical carcinogens and the mechanisms involved in chemical carcinogenesis; the epidemiology related to the problem, followed by a description of the analytical aspects of detection, monitoring and analysis of carcinogens, as well as a discussion on the regulatory aspects and the regulations in place; and the findings, recommendations and concluding remarks of this study. Several problem areas became apparent as the study proceeded. For example, the classification of a chemical as a human carcinogen is a difficult problem, as is its adequate monitoring and analysis. This situation reflects, in turn, the regulatory aspects in the workplace. A list of chemical carcinogens used industrially at the four Canadian nuclear facilities has been identified. The list includes arsenic, asbestos, benzene, cadmium, beryllium, nickel, polychlorinated biphenyls, lead and trichloroethylene. Several recommendations are made in relation to the need for practical and efficient monitoring methods for chemical carcinogens, the definition of radiation and chemical dose equivalencies, and the classification of human chemical carcinogens, as well as their disposal. (author). 122 refs., 8 tabs., 6 figs

  16. Towards incorporating epigenetic mechanisms into carcinogen identification and evaluation.

    Science.gov (United States)

    Herceg, Zdenko; Lambert, Marie-Pierre; van Veldhoven, Karin; Demetriou, Christiana; Vineis, Paolo; Smith, Martyn T; Straif, Kurt; Wild, Christopher P

    2013-09-01

    Remarkable progress in the field of epigenetics has turned academic, medical and public attention to the potential applications of these new advances in medicine and various fields of biomedical research. The result is a broader appreciation of epigenetic phenomena in the a etiology of common human diseases, most notably cancer. These advances also represent an exciting opportunity to incorporate epigenetics and epigenomics into carcinogen identification and safety assessment. Current epigenetic studies, including major international sequencing projects, are expected to generate information for establishing the 'normal' epigenome of tissues and cell types as well as the physiological variability of the epigenome against which carcinogen exposure can be assessed. Recently, epigenetic events have emerged as key mechanisms in cancer development, and while our search of the Monograph Volume 100 revealed that epigenetics have played a modest role in evaluating human carcinogens by the International Agency for Research on Cancer (IARC) Monographs so far, epigenetic data might play a pivotal role in the future. Here, we review (i) the current status of incorporation of epigenetics in carcinogen evaluation in the IARC Monographs Programme, (ii) potential modes of action for epigenetic carcinogens, (iii) current in vivo and in vitro technologies to detect epigenetic carcinogens, (iv) genomic regions and epigenetic modifications and their biological consequences and (v) critical technological and biological issues in assessment of epigenetic carcinogens. We also discuss the issues related to opportunities and challenges in the application of epigenetic testing in carcinogen identification and evaluation. Although the application of epigenetic assays in carcinogen evaluation is still in its infancy, important data are being generated and valuable scientific resources are being established that should catalyse future applications of epigenetic testing.

  17. Biologic markers in risk assessment for environmental carcinogens

    Energy Technology Data Exchange (ETDEWEB)

    Perera, F.; Mayer, J.; Santella, R.M.; Brenner, D.; Jeffrey, A.; Latriano, L.; Smith, S.; Warburton, D.; Young, T.L.; Tsai, W.Y.; Brandt-Rauf, P. (Columbia Univ. School of Public Health, New York, NY (United States)); Hemminki, K. (Finnish School of Occupational Health, Helsinki (Finland))

    1991-01-01

    The potential of biologic markers to provide more timely and precise risk assessments for environmental carcinogens is viewed against the current state-of-the-art in biological monitoring/molecular epidemiology. Biologic markers such as carcinogen-DNA adducts and oncogene activation are currently considered valid qualitative indicators of potential risk, but for most chemical exposures research is needed to establish their validity as quantitative predictors of cancer risk. Biologic markers have, however, already provided valuable insights into the magnitude of interindividual variation in response to carcinogenic exposures, with major implications for risk assessment.

  18. Biologic markers in risk assessment for environmental carcinogens

    International Nuclear Information System (INIS)

    The potential of biologic markers to provide more timely and precise risk assessments for environmental carcinogens is viewed against the current state-of-the-art in biological monitoring/molecular epidemiology. Biologic markers such as carcinogen-DNA adducts and oncogene activation are currently considered valid qualitative indicators of potential risk, but for most chemical exposures research is needed to establish their validity as quantitative predictors of cancer risk. Biologic markers have, however, already provided valuable insights into the magnitude of interindividual variation in response to carcinogenic exposures, with major implications for risk assessment

  19. Studies on carcinogenicity or anticarcinogenicity of isonicotinic acid hydrazide and caffeine by nine-week assay system

    International Nuclear Information System (INIS)

    According to many surveys, cancer is one of the major causes of death in most developed countries and the incidence of cancer appears to be on the increase. Therefore, many studies on detection of carcinogenic or anticarcinogenic agents need urgently. The purpose of this investigation is evaluation the carcinogenic or anticarcinogenic effect of INH and caffeine, which were interpreted as showing either the presence or the absence of a carcinogenic or anticarcinogenic effect, using nine-week assay system. The non-inbred NIH(GP) newborn mice were injected subcutaneously with NIH(400,425, 450 or 480 μg/ head) or caffeine (75 or 100 μg/head) for evaluation of carcinogenicity. Caffeine (1 or 2 mg/ml of drinking water) was administered orally to the mice, which were injected subcutaneously with BP(500μg/head) at new-born, during 6 weeks after weaning for evaluation of anticarcinogenicity. Each group was killed at 9 weeks after the start of exanination. All major organs were examined grossly and histopathologically. Decreased lung adenoma incidence was observed statistically significant in mice fed with caffeine 1 mg(18.8%) or 2 mg(5.1%) per ml of drinking water compared to BP control group (41.3%). However, there was no statistical difference in the incidence of lung and other site tumor between the INH group and the normal control group or between caffeine injection group and normal control group. This result will be contribute to the prevention of cancer from the viewpoint of identifying carcinogenic or anticarcinogenic agents from the environment. (Author)

  20. Temporal aspects of tumorigenic response to individual and mixed carcinogens. Comprehensive progress report, June 1, 1975--May 31, 1978. [Mouse skin, rats, hamsters

    Energy Technology Data Exchange (ETDEWEB)

    Albert, R.E.; Burns, F.J.; Altshuler, B.

    1978-02-01

    The research proposed here is designed to obtain a better understanding of the temporal kinetics of tumor induction when one or more carcinogens are present simultaneously or sequentially for prolonged periods of time. Studies done to date under this contract have shown that carcinogenesis in mouse skin by polycyclic aromatic hydrocarbon carcinogens is consistent with the induction of dependent and autonomous cell transformations by the carcinogen followed by the conversion of autonomous tumor cells into malignancies at a rate which is determined by the level of carcinogen exposure. Dependent cell transformations remain latent in the skin unless expressed by a promoting agent. Dependent neoplasia appears to follow one-hit kinetics while malignancy is a multihit endpoint. Dose-related and time-related aspects of tumor induction are separable in the initiation-promotion system of mouse skin which along with rat skin and hamster lung is being used as a model for testing hypotheses. Results to date provide the basis for a new interpretation of the linear non-threshold extrapolation model. The broad aim of the study is to provide a basis or rationale for estimating risks associated with prolonged exposures to carcinogens found in the environment and to predict how different tissues and species respond to the same carcinogens.

  1. Hepatic gene mutations induced in Big Blue rats by both the potent rat liver azo-carcinogen 6BT and its reported noncarcinogenic analogue 5BT.

    Science.gov (United States)

    Fletcher, K; Soames, A R; Tinwell, H; Lefevre, P A; Ashby, J

    1999-01-01

    The potent rat liver carcinogen 6-p-dimethylaminophenylazobenzthiazole (6BT) and its reported noncarcinogenic analogue 5-p-dimethylaminophenylazobenzthiazole (5BT; evaluated for carcinogenicity under the similar limited bioassay conditions used for 6BT) have been studied in order to seek an explanation for their different carcinogenic activities. Both compounds act as DNA-damaging agents to the rat liver, and both have now been shown to induce lacI (-) gene mutations in the liver of Big Blue(trade mark) transgenic rats. Both compounds were mutagenic following ten daily gavage doses or following administration in diet for 10 days. Neither chemical induced cell proliferation in the liver following repeat gavage administrations. In contrast, dietary administration of 6BT, and to a lesser extent of 5BT, induced hepatic cell proliferation. The carcinogen 6BT, but not the noncarcinogen 5BT, caused proliferation of oval stem cells in the livers by both routes of administration. It is possible that mutations induced in oval cells by 6BT are responsible for its potent carcinogenicity, and that the comparative absence of these cells in 5BT-treated livers may account for the carcinogenic inactivity of 5BT. Equally, the proliferation of the oval cells may reflect changes in liver homeostasis associated with the liver toxicity observed at the dose level of 6BT used (which was, nonetheless, the dose level used in the positive cancer bioassays). It is concluded that the new data presented cannot explain the differing carcinogenic activities of 5BT and 6BT, and that the reported noncarcinogen 5BT may also be carcinogenic when adequately assessed for this activity.

  2. Carcinogenicity and co-carcinogenicity studies on propoxur in mouse skin.

    Science.gov (United States)

    Shukla, Y; Baqar, S M; Mehrotra, N K

    1998-12-01

    Propoxur (2-isopropoxyphenyl methylcarbamate) is a widely used broad spectrum carbamate insecticide mainly used to control household pests. Propoxur exposure is reported to inhibit cholinesterase activity in rodents. Apart from other toxic effects, propoxur was found to possess tumorigenic activity in rats after oral administration. Propoxur does not produce tumours in mice or hamsters, or bladder hyperplasia in dogs and monkeys following oral feeding. In this set of investigations the complete carcinogenic, tumour initiating and promoting potential of propoxur was evaluated in male and female Swiss albino mice, since no information was available following dermal exposure of propoxur. The animals were exposed to propoxur through topical painting on the interscapular region at a dose of 100 mg/kg body weight. The results revealed that propoxur has tumour promoting potential on mouse skin following a two-stage initiation-promotion protocol, but it failed to induce the tumour(s) at a significant level, when tested for tumour initiating and complete carcinogenic property.

  3. Trichloroethylene: Mechanistic, Epidemiologic and Other Supporting Evidence of Carcinogenic Hazard

    OpenAIRE

    Rusyn, Ivan; Chiu, Weihsueh A.; Lawrence H. Lash; Kromhout, Hans; Hansen, Johnni; Guyton, Kathryn Z.

    2013-01-01

    The chlorinated solvent trichloroethylene (TCE) is a ubiquitous environmental pollutant. The carcinogenic hazard of TCE was the subject of a 2012 evaluation by a Working Group of the International Agency for Research on Cancer (IARC). Information on exposures, relevant data from epidemiologic studies, bioassays in experimental animals, and toxicity and mechanism of action studies was used to conclude that TCE is carcinogenic to humans (Group 1). This article summarizes the key evidence formin...

  4. Critical analysis of carcinogenicity study outcomes. Relationship with pharmacological properties.

    Science.gov (United States)

    van der Laan, Jan Willem; Kasper, Peter; Silva Lima, Beatriz; Jones, David R; Pasanen, Markku

    2016-08-01

    Predicting the outcome of life-time carcinogenicity studies in rats based on chronic (6-month) toxicity studies in this species is possible in some instances. This should reduce the number of such studies and hence have a significant impact on the total number of animals used in safety assessment of new medicines. From a regulatory perspective, this should be sufficient to grant a waiver for a carcinogenicity study in those cases where there is confidence in the outcome of the prediction. Pharmacological properties are a frequent key factor for the carcinogenic mode of action of some pharmaceuticals, but data-analysis on a large dataset has never been formally conducted. We have conducted an analysis of a dataset based on the perspective of the pharmacology of 255 compounds from industrial and regulatory sources. It is proposed that a pharmacological, class-specific, model may consist of an overall causal relationship between the pharmacological class and the histopathology findings in rats after 6 months treatment, leading to carcinogenicity outcome after 2 years. Knowledge of the intended drug target and pathway pharmacology should enhance the prediction of either positive or negative outcomes of rat carcinogenicity studies. The goal of this analysis is to review the pharmacological properties of compounds together with the histopathology findings from the chronic toxicity study in rodents in order to introduce an integrated approach to estimate the risk of human carcinogenicity of pharmaceuticals. This approach would allow scientists to define conditions under which 2-year rat carcinogenicity studies will or will not add value to such an assessment. We have demonstrated the possibility of a regulatory waiver for a carcinogenicity study in rats, as currently discussed in the International Council for Harmonization (ICH) - formerly known as the International Conference on Harmonization (ICH), by applying the proposed prediction approach in a number of case studies

  5. Biologic markers in risk assessment for environmental carcinogens

    OpenAIRE

    Perera, F.; Mayer, J.; Santella, R. M.; Brenner, D; Jeffrey, A.; Latriano, L; Smith, S.; Warburton, D; Young, T. L.; Tsai, W. Y.; Hemminki, K; Brandt-Rauf, P

    1991-01-01

    The potential of biologic markers to provide more timely and precise risk assessments for environmental carcinogens is viewed against the current state-of-the-art in biological monitoring/molecular epidemiology. Biologic markers such as carcinogen-DNA adducts and oncogene activation are currently considered valid qualitative indicators of potential risk, but for most chemical exposures research is needed to establish their validity as quantitative predictors of cancer risk. Biologic markers h...

  6. 复配抗菌剂对紫外光固化抗菌涂料性能的影响%Effect of Compound Antibacterial Agents on Properties of UV Curing Antimicrobial Coating

    Institute of Scientific and Technical Information of China (English)

    王晓慧; 宋伟强; 遆永周; 吕晓华; 邓刚; 孟闯

    2016-01-01

    采用紫外光固化技术,以自制抗菌剂三丁基对乙烯基苄基氯化鏻(DA)与甲基丙烯酰氧乙基十二烷基二甲基溴化铵(VP)复配作为抗菌单体,制备了紫外光固化抗菌涂料.研究了抗菌单体对固化膜性能的影响,并测试了紫外光固化抗菌涂料的理化性能和抗菌性能.结果表明:抗菌单体对固化膜性能有显著影响;当DA/VP用量比为0.4时,固化膜硬度、附着力和抗冲击性均能达到最佳;制备的紫外光固化抗菌涂料具有良好的抗菌性能,其各项理化性能均达到国家或行业标准.%The UV curable antimicrobial coating was prepared by UV curing technology with tributyl vinyl benzyl phosphonium chloride(DA)and methyl acryloyloxyethyl dodecyl dimethyl ammonium bromide(VP)as antibacterial monomer. The effect of antibacterial monomer ratio on the properties of the cured film was studied. The antibacterial properties and the physical and chemical properties of the UV cured coatings were tested. The results showed that the antibacterial monomer has a significant influence on the properties of cured film. When the amount of DA/VP ratio is 0.4,curing film hardness,adhesion,impact resistance and gloss can reach the optimum. The prepared UV curable antimicrobial coatings have excellent antibacterial properties ,and the physical and chemical properties have reached the national standard or industry standard.

  7. Best practices for clinical pathology testing in carcinogenicity studies.

    Science.gov (United States)

    Young, Jamie K; Hall, Robert L; O'Brien, Peter; Strauss, Volker; Vahle, John L

    2011-02-01

    The Society of Toxicologic Pathology (STP) and American Society for Veterinary Clinical Pathology (ASCVP) convened a Clinical Pathology in Carcinogenicity Studies Working Group to recommend best practices for inclusion of clinical pathology testing in carcinogenicity studies. Regulatory guidance documents and literature were reviewed, and veterinary pathologists from North America, Japan, and Europe were surveyed regarding current practices, perceived value, and recommendations for clinical pathology testing in carcinogenicity studies. For two-year rodent carcinogenicity studies, the Working Group recommends that clinical pathology testing be limited to collection of blood smears at scheduled and unscheduled sacrifices to be examined only if indicated to aid in the diagnosis of possible hematopoietic neoplasia following histopathologic evaluation. Additional clinical pathology testing is most appropriately used to address specific issues from prior toxicity studies or known test article-related class effects. Inadequate data were available to make a recommendation concerning clinical pathology testing for alternative six-month carcinogenicity assays using genetically modified mice, although the Working Group suggests that it may be appropriate to use the same approach as for two-year carcinogenicity studies since the study goal is the same.

  8. An international literature survey of "IARC Group I carcinogens" reported in mainstream cigarette smoke.

    Science.gov (United States)

    Smith, C J; Livingston, S D; Doolittle, D J

    1997-01-01

    The International Agency for Research on Cancer (IARC) currently lists 44 individual chemical agents, 12 groups or mixtures of chemicals and 13 exposure circumstances as "Group 1 human carcinogens". A comprehensive search of the published literature revealed that nine of the 44 chemical agents classified as "Group I carcinogens" by IARC have been reported to occur in mainstream cigarette smoke. The other 35 have never been reported to occur in cigarette smoke. The nine agents reported are benzene, cadmium, arsenic, nickel, chromium, 2-naphthyl-amine, vinyl chloride, 4-aminobiphenyl and beryllium. The reported yields of each of these nine agents in mainstream smoke varies widely. The range of yields reported for a given compound is influenced by the type of cigarette tested and when the analysis was conducted. In micrograms/cigarette, the ranges that have been reported for each of the nine compounds are: benzene (0.05-104), cadmium (0-6.67), arsenic (0-1.4), nickel (0-0.51), chromium (0.0002-0.5), 2-naphthylamine (0.0002-0.022), vinyl chloride (0.0013-0.0158), 4-aminobiphenyl (0.00019-0.005) and beryllium (0-0.0005). Although some of the variation in reported yields may be due to differences in analytical methodology, several correlations between the yield of a particular chemical in mainstream smoke and certain cigarette characteristics were observed. For example, charcoal filtration was associated with reduced vinyl chloride, and the concentration of sodium nitrate in the tobacco was positively correlated with the mainstream yield of both 2-naphthylamine and 4-aminobiphenyl. Benzene yield in mainstream cigarette smoke was correlated with the amount of tobacco burned and with the 'tar' level. Agronomic factors such as production practices and soil characteristics, and environmental conditions such as rainfall, reportedly influence the accumulation of metals, for example, cadmium, beryllium, chromium, nickel and arsenic, in the leaf. The use of fertilizers low in

  9. Induction of active melanocytes in mouse skin by carcinogens: a new method for detection of skin carcinogens.

    Science.gov (United States)

    Iwata, K; Inui, N; Takeuchi, T

    1981-01-01

    Application of potent skin carcinogens, such as 7,12-dimethylbenz[a]anthracene, 3-methylcholanthrene, benzo[a]pyrene and 4-nitroquinoline-1-oxide, induced numerous dihydroxyphenylalanine (dopa)-positive cells in the interfollicular epidermis of C57BL/6 mice in a dose- and time-dependent fashion. Chrysene, a weak skin carcinogen, and croton oil, a tumor promoter, also induced 3--4 times more dopa-positive cells than acetone. Liver carcinogens, such as 3'-methyl-4-dimethylaminoazobenzene and N-2-acetylaminofluorene, and non-carcinogenic aromatic hydrocarbons, such as anthracene, fluoranthene, fluorene and pyrene, did not induce increase in these cells. These results indicate that increase in the number of dopa-positive cells after application of chemicals is well correlated with the abilities of these compounds to induce skin carcinogenesis and suppress sebaceous glands. PMID:7273337

  10. Two azole fungicides (carcinogenic triadimefon and non-carcinogenic myclobutanil) exhibit different hepatic cytochrome P450 activities in medaka fish

    International Nuclear Information System (INIS)

    Highlights: • We assess ecotoxicological impact of azole fungicides in the aquatic environment. • Carcinogenic and non-carcinogenic azoles show different CYP activities in medaka. • We compare azole-induced CYP expression and carcinogenesis between fish and rodents. • Liver CYP-enzyme induction is a key event in conazole-induced tumorigenesis. • We suggest toxicity evaluation methods for azole fungicides using medaka fish. - Abstract: Conazoles are a class of imidazole- or triazole-containing drugs commonly used as fungicides in agriculture and medicine. The broad application of azole drugs has led to the contamination of surface aquifers receiving the effluent of municipal or hospital wastewater or agricultural runoff. Several triazoles are rodent carcinogens; azole pollution is a concern to environmental safety and human health. However, the carcinogenic mechanisms associated with cytochrome P450 enzymes (CYPs) of conazoles remain unclear. We exposed adult medaka fish (Oryzias latipes) to continuous aqueous solutions of carcinogenic triadimefon and non-carcinogenic myclobutanil for 7 to 20 days at sub-lethal or environmentally relevant concentrations and assessed hepatic CYP activity and gene expression associated with CYP-mediated toxicity. Both triadimefon and myclobutanil induced hepatic CYP3A activity, but only triadimefon enhanced CYP1A activity. The gene expression of cyp3a38, cyp3a40, pregnane x receptor (pxr), cyp26b, retinoid acid receptor γ1 (rarγ1) and p53 was higher with triadimefon than myclobutanil. As well, yeast-based reporter gene assay revealed that 4 tested conazoles were weak agonists of aryl hydrocarbon receptor (AhR). We reveal differential CYP gene expression with carcinogenic and non-carcinogenic conazoles in a lower vertebrate, medaka fish. Liver CYP-enzyme induction may be a key event in conazole-induced tumorigenesis. This information is essential to evaluate the potential threat of conazoles to human health and fish

  11. Two azole fungicides (carcinogenic triadimefon and non-carcinogenic myclobutanil) exhibit different hepatic cytochrome P450 activities in medaka fish

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Chun-Hung [Department of Agricultural Chemistry, National Taiwan University, Taipei, Taiwan (China); Chou, Pei-Hsin [Department of Environmental Engineering, National Cheng-Kung University, Tainan, Taiwan (China); Chen, Pei-Jen, E-mail: chenpj@ntu.edu.tw [Department of Agricultural Chemistry, National Taiwan University, Taipei, Taiwan (China)

    2014-07-30

    Highlights: • We assess ecotoxicological impact of azole fungicides in the aquatic environment. • Carcinogenic and non-carcinogenic azoles show different CYP activities in medaka. • We compare azole-induced CYP expression and carcinogenesis between fish and rodents. • Liver CYP-enzyme induction is a key event in conazole-induced tumorigenesis. • We suggest toxicity evaluation methods for azole fungicides using medaka fish. - Abstract: Conazoles are a class of imidazole- or triazole-containing drugs commonly used as fungicides in agriculture and medicine. The broad application of azole drugs has led to the contamination of surface aquifers receiving the effluent of municipal or hospital wastewater or agricultural runoff. Several triazoles are rodent carcinogens; azole pollution is a concern to environmental safety and human health. However, the carcinogenic mechanisms associated with cytochrome P450 enzymes (CYPs) of conazoles remain unclear. We exposed adult medaka fish (Oryzias latipes) to continuous aqueous solutions of carcinogenic triadimefon and non-carcinogenic myclobutanil for 7 to 20 days at sub-lethal or environmentally relevant concentrations and assessed hepatic CYP activity and gene expression associated with CYP-mediated toxicity. Both triadimefon and myclobutanil induced hepatic CYP3A activity, but only triadimefon enhanced CYP1A activity. The gene expression of cyp3a38, cyp3a40, pregnane x receptor (pxr), cyp26b, retinoid acid receptor γ1 (rarγ1) and p53 was higher with triadimefon than myclobutanil. As well, yeast-based reporter gene assay revealed that 4 tested conazoles were weak agonists of aryl hydrocarbon receptor (AhR). We reveal differential CYP gene expression with carcinogenic and non-carcinogenic conazoles in a lower vertebrate, medaka fish. Liver CYP-enzyme induction may be a key event in conazole-induced tumorigenesis. This information is essential to evaluate the potential threat of conazoles to human health and fish

  12. Two azole fungicides (carcinogenic triadimefon and non-carcinogenic myclobutanil) exhibit different hepatic cytochrome P450 activities in medaka fish.

    Science.gov (United States)

    Lin, Chun-Hung; Chou, Pei-Hsin; Chen, Pei-Jen

    2014-07-30

    Conazoles are a class of imidazole- or triazole-containing drugs commonly used as fungicides in agriculture and medicine. The broad application of azole drugs has led to the contamination of surface aquifers receiving the effluent of municipal or hospital wastewater or agricultural runoff. Several triazoles are rodent carcinogens; azole pollution is a concern to environmental safety and human health. However, the carcinogenic mechanisms associated with cytochrome P450 enzymes (CYPs) of conazoles remain unclear. We exposed adult medaka fish (Oryzias latipes) to continuous aqueous solutions of carcinogenic triadimefon and non-carcinogenic myclobutanil for 7 to 20 days at sub-lethal or environmentally relevant concentrations and assessed hepatic CYP activity and gene expression associated with CYP-mediated toxicity. Both triadimefon and myclobutanil induced hepatic CYP3A activity, but only triadimefon enhanced CYP1A activity. The gene expression of cyp3a38, cyp3a40, pregnane x receptor (pxr), cyp26b, retinoid acid receptor γ1 (rarγ1) and p53 was higher with triadimefon than myclobutanil. As well, yeast-based reporter gene assay revealed that 4 tested conazoles were weak agonists of aryl hydrocarbon receptor (AhR). We reveal differential CYP gene expression with carcinogenic and non-carcinogenic conazoles in a lower vertebrate, medaka fish. Liver CYP-enzyme induction may be a key event in conazole-induced tumorigenesis. This information is essential to evaluate the potential threat of conazoles to human health and fish populations in the aquatic environment. PMID:24962053

  13. Effect of smokeless tobacco and tobacco-related chemical carcinogens on survival of ultraviolet light-inactivated herpes simplex virus

    Energy Technology Data Exchange (ETDEWEB)

    Dokko, H.; Min, P.S.; Cherrick, H.M.; Park, N.H. (Section of Oral and Maxillofacial Surgery, UCLA School of Dentistry (USA))

    1991-04-01

    Low doses of ultraviolet (UV) light, x-rays, photodynamic treatment, or aflatoxins increase the survival of UV-irradiated virus in cells. This effect is postulated to occur by enhancement of the error-prone cellular repair function, which could also be associated with oncogenic cell transformation. The present study was designed to investigate whether treatment of green monkey kidney cells with water extract of snuff (snuff extract), benzo(a)pyrene, nicotine, or tobacco-specific N'-nitrosamines would result in enhanced survival of UV-irradiated herpes simplex virus (HSV). Exposure of the cells with snuff extract, benzo(a)pyrene, N'-nitrosonornicotine, or 4-(N-methyl-N'-nitrosamino)-1-(3-pyridyl)-1-butanone resulted in an enhancement of survival of UV-irradiated HSV type 1 compared with the control whereas exposure of the cells with nicotine did not. These data indicate that the water-extractable component of snuff and tobacco-related chemical carcinogens increase the cellular repair mechanism and provides for increased survival of UV-irradiated HSV.

  14. Monitoring human exposure to 2-hydroxyethylating carcinogens

    DEFF Research Database (Denmark)

    Farmer, P.B.; Cordero, Rosa; Autrup, Herman

    1996-01-01

    It is known that human hemoglobin contains low levels of N-terminal N-(2-hydroxyethyl)valine. Possible sources of this modified amino acid are exposure to ethylene oxide or other 2-hydroxy-ethylating agents. Although such processes are likely to occur endogenously, the exogenous contribution...... to the adduct formation is unclear. In order to explore the latter, we have analyzed N-(2-hydroxyethyl)valine in the globin of 49 pregnant women and evaluated the effect of smoking status, area of residence, and glutathione S-transferase M1 genotype on adduct levels. Transplacental transfer of hydroxyethylating......-transferase M1 genotype on levels of N-(2-hydroxyethyl)valine....

  15. Chronic exposure to combined carcinogens enhances breast cell carcinogenesis with mesenchymal and stem-like cell properties.

    Directory of Open Access Journals (Sweden)

    Lenora Ann Pluchino

    Full Text Available Breast cancer is the most common type of cancer affecting women in North America and Europe. More than 85% of breast cancers are sporadic and attributable to long-term exposure to small quantities of multiple carcinogens. To understand how multiple carcinogens act together to induce cellular carcinogenesis, we studied the activity of environmental carcinogens 4-(methylnitrosamino-1-(3-pyridyl-1-butanone (NNK and benzo[a]pyrene (B[a]P, and dietary carcinogen 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP using our breast cell carcinogenesis model. Our study revealed, for the first time, that combined NNK and B[a]P enhanced breast cell carcinogenesis chronically induced by PhIP in both non-cancerous and cancerous breast cells. Co-exposure was more potent than sequential exposure to combined NNK and B[a]P followed by PhIP in inducing carcinogenesis. Initiation of carcinogenesis was measured by transient endpoints induced in a single exposure, while progression of carcinogenesis was measured by acquisition of constitutive endpoints in cumulative exposures. Transient endpoints included DNA damage, Ras-Erk-Nox pathway activation, reactive oxygen species elevation, and increased cellular proliferation. Constitutive endpoints included various cancer-associated properties and signaling modulators, as well as enrichment of cancer stem-like cell population and activation of the epithelial-to-mesenchymal transition program. Using transient and constitutive endpoints as targets, we detected that a combination of the green tea catechins ECG and EGCG, at non-cytotoxic levels, was more effective than individual agents in intervention of cellular carcinogenesis induced by combined NNK, B[a]P, and PhIP. Thus, use of combined ECG and EGCG should be seriously considered for early intervention of breast cell carcinogenesis associated with long-term exposure to environmental and dietary carcinogens.

  16. Arsenic Transformation Predisposes Human Skin Keratinocytes To UV-induced DNA Damage Yet Enhances Their Survival Apparently by Diminishing Oxidant Response

    OpenAIRE

    Sun, Yang(Department of Physics, Shanghai Jiao Tong University, Shanghai 200240, China); Kojima, Chikara; Chignell, Colin; Mason, Ronald; Waalkes, Michael P.

    2011-01-01

    Inorganic arsenic and UV, both human skin carcinogens, may act together as skin co-carcinogens. We find human skin keratinocytes (HaCaT cells) are malignantly transformed by low-level arsenite (100 nM, 30 weeks; termed As-TM cells) and with transformation concurrently undergo full adaptation to arsenic toxicity involving reduced apoptosis and oxidative stress response to high arsenite concentrations. Oxidative DNA damage (ODD) is a possible mechanism in arsenic carcinogenesis and a hallmark o...

  17. WSO-UV project

    Science.gov (United States)

    Sachkov, Mikhail; Shustov, Boris; Gómez de Castro, Ana Ines

    2014-03-01

    During last three decades, astronomers have enjoyed continuous access to the 100-300 nm ultraviolet (UV) spectral range where the resonance transitions of the most abundant atoms and ions (at temperatures between 3000 and 300 000 K) reside. This UV range is not accessible from ground-based facilities. The successful International Ultraviolet Explorer (IUE) observatory, the Russian ASTRON mission and successor instruments such as the Galaxy Evolution Explorer (GALEX) mission or the COS and STIS spectrographs on-board the Hubble Space Telescope (HST) prove the major impact of observations in the UV wavelength range in modern astronomy. Future access to space-based observatories is expected to be very limited. For the next decade, the post-HST era, the World Space Observatory - Ultraviolet (WSO-UV) will be the only 2-m class UV telescope with capabilities similar to the HST. WSO-UV will be equipped with instruments for imaging and spectroscopy and it will be a facility dedicated, full-time, to UV astronomy. In this article, we briefly outline the current status of the WSO-UV mission and the science management plan.

  18. UV-induced effects

    NARCIS (Netherlands)

    Liebsch, M.; Spielmann, H.; Pape, W.; Krul, C.; Deguercy, A.; Eskes, C.A.M.

    2005-01-01

    Regulatory requirements: According to the current Notes for Guidance of the Scientific Committee on Cosmetic Products and Non-Food Products (SCCNFP), cosmetic ingredients and mixtures of ingredients absorbing UV light (in particular UV filter chemicals used, for example, to ensure the light stabilit

  19. Food Additives of Public Concern for their Carcinogenicity

    Directory of Open Access Journals (Sweden)

    Fatih Gultekin

    2015-08-01

    Full Text Available No-Observed-Adverse Effect Level (NOAEL of food additives has been long determined on the basis of toxicological studies. Acceptable Daily Intake (ADI levels of food additives for human are derived from these NOAEL, and their legal limits are then established for the food products, intentionally added with food additives. However, recent studies demonstrated that consumption of some processed food containing certain food additives might have increased the risk of cancer in human although the legal limits of these additives in processed foods are well respected by the manufacturers. Possible reasons for increased carcinogenicity risk in processed foods containing these additives can be due to various factors: -interaction of additives with some food ingredients, -food processing may change the chemical formula of food additive to a formula to be acting similarly as carcinogenic compound, -a negative synergistic effects when combined with other additives, -improper storage conditions, and -unknown carcinogenic by-products occurring during the food processing. Due to the above mentioned factors we recommend that an additive, intentionally added to the food during processing must be traced officially for its carcinogenicity. In this review, we overviewed all of the food additives authorized in European Union. Therefore, the traceability issues of processed foods containing certain food additives, which have a negligible probability of carcinogenicity in legal limits, must be reinforced in the perspective of public health concerns.

  20. Arsenic transformation predisposes human skin keratinocytes to UV-induced DNA damage yet enhances their survival apparently by diminishing oxidant response

    International Nuclear Information System (INIS)

    Inorganic arsenic and UV, both human skin carcinogens, may act together as skin co-carcinogens. We find human skin keratinocytes (HaCaT cells) are malignantly transformed by low-level arsenite (100 nM, 30 weeks; termed As-TM cells) and with transformation concurrently undergo full adaptation to arsenic toxicity involving reduced apoptosis and oxidative stress response to high arsenite concentrations. Oxidative DNA damage (ODD) is a possible mechanism in arsenic carcinogenesis and a hallmark of UV-induced skin cancer. In the current work, inorganic arsenite exposure (100 nM) did not induce ODD during the 30 weeks required for malignant transformation. Although acute UV-treatment (UVA, 25 J/cm2) increased ODD in passage-matched control cells, once transformed by arsenic to As-TM cells, acute UV actually further increased ODD (> 50%). Despite enhanced ODD, As-TM cells were resistant to UV-induced apoptosis. The response of apoptotic factors and oxidative stress genes was strongly mitigated in As-TM cells after UV exposure including increased Bcl2/Bax ratio and reduced Caspase-3, Nrf2, and Keap1 expression. Several Nrf2-related genes (HO-1, GCLs, SOD) showed diminished responses in As-TM cells after UV exposure consistent with reduced oxidant stress response. UV-exposed As-TM cells showed increased expression of cyclin D1 (proliferation gene) and decreased p16 (tumor suppressor). UV exposure enhanced the malignant phenotype of As-TM cells. Thus, the co-carcinogenicity between UV and arsenic in skin cancer might involve adaptation to chronic arsenic exposure generally mitigating the oxidative stress response, allowing apoptotic by-pass after UV and enhanced cell survival even in the face of increased UV-induced oxidative stress and increased ODD. - Highlights: → Arsenic transformation adapted to UV-induced apoptosis. → Arsenic transformation diminished oxidant response. → Arsenic transformation enhanced UV-induced DNA damage.

  1. Evaluation of tests using DNA repair-deficient bacteria for predicting genotoxicity and carcinogenicity

    Energy Technology Data Exchange (ETDEWEB)

    Leifer, Z.; Kada, T.; Mandel, M.; Zeiger, E.; Stafford, R.; Rosenkranz, H.S.

    1981-01-01

    The detection of DNA-damaging agents by repair-deficient bacterial assays is based on the differential inhibition of growth of repair-proficient and repair-deficient bacterial pairs. The various methodologies used are described and recommendations are made for their improved use. In a survey of the literature through April 1979, 91 of 276 papers evaluated contained usable data, resulting in an analysis of 611 compounds that had been assayed in 1 or more of 55 pairs of repair-proficient and repair-deficient strains. The results indicate that a liquid suspension assay is more sensitive than a spot (diffusion) test. There was a 78% correspondence between results obtained with E. coli polA and Bacillus subtilis (H17/M45, 17A/45T) rec assay and between E. coli polA and Proteus mirabilis. In a comparison of test results with carcinogenicity data, 44 of 71 (62%) carcinogenic compounds assayed by the polA system were positive, 10 (14%) were negative, and 17 (24%) gave No Test or doubtful results. The results were analyzed with respect to chemical classes. E. coli polA detected the highest percentage of hydroxylamines and alkyl epoxides. The B. subtilis rec assay detected the highest percentage of nitrosamines and sulfur and nitrogen oxides. It is concluded that some of these test systems are effective tools for the detection of DNA-damaging and potentially carcinogenic compounds, especially if the assay is done in liquid suspension and if more than 1 pair of tester strains is used. Advantages and disadvantages of the assay are discussed and suggestions are made for improvements in the system.

  2. Studies in vitro to discern the structural requirements for carcinogenicity in analogues of the carcinogen 4-dimethylaminoazobenzene (butter yellow).

    Science.gov (United States)

    Ashby, J; Styles, J A; Paton, D

    1980-01-01

    4-Dimethylaminoazobenzene (butter yellow, DAB), is the parent member of a large family of 'azo-carcinogens'. Experiments have been conducted in vitro to determine the key structural requirements for carcinogenic activity in this chemical class, and it is suggested, based on the activity observed for 4-cyano-N,N-dimethylaniline, that the 4-phenylazo group of DAB is not an essential structural feature per se. The N-oxide derivative of DAB has been evaluated in vitro and the positive response observed related to its metabolic activation. It is concluded that cyclic amines, such as pyrrolidine, can replace the N-dimethyl group of DAB with a retention of biological activity. The confusion that exists in the literature concerning the chemical identity and carcinogenic status of 2-dimethylaminobenzo[c]cinnoline has been investigated, and it is concluded that it is a potential animal carcinogen. This observation also indicates that the phenylazo group of DAB can be incorporated within an aromatic ring system with a retention of biological activity. As observed earlier with a mixture of azobenzene and DAB, azobenzene also potentiates the cell transforming properties of the above cinnoline derivative in vitro. Two charts are presented. The first attempts to integrate DAB within a much larger family of carcinogens, and the second illustrates the usefulness of structure-activity studies in general.

  3. Research Recommendations for Selected IARC-Classified Agents

    DEFF Research Database (Denmark)

    Ward, Elizabeth M; Schulte, Paul A; Straif, Kurt;

    2010-01-01

    OBJECTIVES: There are some common occupational agents and exposure circumstances where evidence of carcinogenicity is substantial but not yet conclusive for humans. The objectives are to identify research gaps and needs for twenty agents prioritized for review based on evidence of widespread human......, focusing on research that would be important in resolving classification uncertainties. An expert meeting brought reviewers together to discuss each agent and the identified data gaps and approaches. DATA SYNTHESIS: Several overarching issues were identified that pertained to multiple agents; these...... included the importance of recognizing that carcinogenic agents can act through multiple toxicity pathways and mechanisms, including epigenetic mechanisms, oxidative stress and immuno- and hormonal modulation. CONCLUSIONS: Studies in occupational populations provide important opportunities to understand...

  4. Current issues in carcinogenic effect of low-dose radiation

    International Nuclear Information System (INIS)

    A review of publications dealing with study of radiation sources and biological evaluation of increasing doses of people irradiation under occupational and usual living conditions is presented. The existing natural and artifial irradiation sources are considered. It is noted that all types of ionizing radiations are characterized by high carcinogenic efficiency and can induce benign and malignant tumors practically in all organs. Statistically reliable data in experimental and epidemiological investigations were recorded under the effect of large and mean doses. Minor radiation doses not responsible for visible functional and morphological changes in early periods can cause pathological changes in delayed periods. The data on carcinogenic effect of relatively small radiation doses are available

  5. Cannabis and tobacco smoke are not equally carcinogenic

    Directory of Open Access Journals (Sweden)

    Melamede Robert

    2005-10-01

    Full Text Available Abstract More people are using the cannabis plant as modern basic and clinical science reaffirms and extends its medicinal uses. Concomitantly, concern and opposition to smoked medicine has occurred, in part due to the known carcinogenic consequences of smoking tobacco. Are these reactions justified? While chemically very similar, there are fundamental differences in the pharmacological properties between cannabis and tobacco smoke. Cannabis smoke contains cannabinoids whereas tobacco smoke contains nicotine. Available scientific data, that examines the carcinogenic properties of inhaling smoke and its biological consequences, suggests reasons why tobacco smoke, but not cannabis smoke, may result in lung cancer.

  6. Environmental carcinogens in human target tissues in culture: Progress report

    International Nuclear Information System (INIS)

    We have accumulated more experimental evidences that demonstrated the comparative approaches with human cells will allow us to predict human risk with good accuracy following exposure to toxic chemicals. We also synthesized several carcinogenic DNA adducts, i.e., the major benzo[a]pyrene DNA adduct, 06-methyldeoxyguanosine, 7-methyl- deoxyguanosine and 2-methyl-deoxyguanosine to be used as standards for quantitating DNA adduct formation in carcinogen exposed cells. A simple synthetic method was developed for preparation of the major B[a]p DNA adduct with yields better than those reported. The main accomplishments related to the originally stated objectives are summarized. 8 refs., 2 figs., 1 tab

  7. UV, stress and aging.

    Science.gov (United States)

    Debacq-Chainiaux, Florence; Leduc, Cedric; Verbeke, Alix; Toussaint, Olivier

    2012-07-01

    Skin is a model of choice in studies on aging. Indeed, skin aging can be modulated by internal and external factors, reflecting its complexity. Two types of skin aging have been identified: intrinsic, mainly genetically determined and extrinsic-also called "photo-aging"-resulting on the impact of environmental stress and more precisely of UV rays. Simplified in vitro models, based on cellular senescence, have been developed to study the relationship between UV and aging. These models vary on the cell type (fibroblasts or keratinocytes, normal or immortalized) and the type of UV used (UVA or UVB). PMID:23467762

  8. UV, stress and aging.

    Science.gov (United States)

    Debacq-Chainiaux, Florence; Leduc, Cedric; Verbeke, Alix; Toussaint, Olivier

    2012-07-01

    Skin is a model of choice in studies on aging. Indeed, skin aging can be modulated by internal and external factors, reflecting its complexity. Two types of skin aging have been identified: intrinsic, mainly genetically determined and extrinsic-also called "photo-aging"-resulting on the impact of environmental stress and more precisely of UV rays. Simplified in vitro models, based on cellular senescence, have been developed to study the relationship between UV and aging. These models vary on the cell type (fibroblasts or keratinocytes, normal or immortalized) and the type of UV used (UVA or UVB).

  9. Another two genes controlling mitotic intragenic recombination and recovery from UV damage in Aspergillus nidulans IV. Genetic analysis of mitotic intragenic recombinants from uvs+/uvs+, uvsD/uvsD and uvsE/uvsE diploids

    NARCIS (Netherlands)

    Fortuin, J.J.H.

    1971-01-01

    This paper presents the results of a genetic analysis of a number of spontaneous mitotic p-aminobenzoic acid-independent recombinants from uvs+/uvs+, uvsD53/uvsD53 and uvsE82/uvsE82 diploids that are heteroallelic at the pabaA locus. Intragenic recombination in each of the three strains is largely n

  10. UV, stress and aging

    OpenAIRE

    Debacq-Chainiaux, Florence; Leduc, Cedric; Verbeke, Alix; Toussaint, Olivier

    2014-01-01

    Skin is a model of choice in studies on aging. Indeed, skin aging can be modulated by internal and external factors, reflecting its complexity. Two types of skin aging have been identified: intrinsic, mainly genetically determined and extrinsic—also called "photo-aging"—resulting on the impact of environmental stress and more precisely of UV rays. Simplified in vitro models, based on cellular senescence, have been developed to study the relationship between UV and aging. These models vary on ...

  11. Chronic toxicity and carcinogenicity study of erythritol in rats

    NARCIS (Netherlands)

    Lina, B.A.R.; Bos-Kuijpers, M.H.M.; Til, H.P.; Bär, A.

    1996-01-01

    The potential toxicity and carcinogenicity of erythritol, a low-calorie sugar substitute, were examined in Wistar Crl:(WI) WU BR rats. Groups of 50 rats of each sex consumed diets with 0, 2, 5, or 10% erythritol, or 10% mannitol, for a period of 104-107 weeks. To each of these main groups, two satel

  12. Flavonoids and alkenylbenzenes: mechanisms of mutagenic action and carcinogenic risk

    NARCIS (Netherlands)

    Rietjens, I.M.C.M.; Boersma, M.G.; Woude, van der H.; Jeurissen, S.M.F.; Schutte, M.E.; Alink, G.M.

    2005-01-01

    The present review focuses on the mechanisms of mutagenic action and the carcinogenic risk of two categories of botanical ingredients, namely the flavonoids with quercetin as an important bioactive representative, and the alkenylbenzenes, namely safrole, methyleugenol and estragole. For quercetin a

  13. Binding of chemical carcinogens to macromolecules in cultured human colon

    DEFF Research Database (Denmark)

    1977-01-01

    Metabolic activation of different chemical classes of carcinogens was studied in cultured human colon epithelia. Human colon epithelia were maintained in explant culture up to 4 days. Binding of benzo(a)pyrene, dimethylnitrosamine, and 1,2- dimethylhydrazine was found in both cell DNA and protein...

  14. Occurrence of the carcinogenic compound ptaquiloside in the soil environment

    DEFF Research Database (Denmark)

    Rasmussen, Lars Holm; Kroghsbo, Stine; Frisvad, Jens Christian;

    2003-01-01

    Bracken (Pteridium aquilinum (L.) Kuhn) is a common fern found on all continents except Antarctica. It is under suspicion of causing cancer among people who utilizes it as food. The main carcinogenic compound is thought to be the water-soluble compound ptaquiloside. Ptaquiloside-uptake may occur...

  15. Modern Electrochemical Methods for Monitoring of Chemical Carcinogens

    OpenAIRE

    Zima, J; Moreira, J.; J. Barek

    2005-01-01

    This contribution is based on our presentation at the 1st International Symposium on Sensor Science, Paris, 16-20 June 2003. It presents recent results regarding the electrochemical determination of submicromolar and nanomolar concentrations of various carcinogenic substances (nitrated polycyclic aromatic hydrocarbons, heterocyclic compounds, azo compounds, aromatic amino compounds, etc.) using both traditional (classical dropping mercury electrode, static mercury drop electrode, hanging merc...

  16. Trichloroethylene: Mechanistic, epidemiologic and other supporting evidence of carcinogenic hazard

    NARCIS (Netherlands)

    Rusyn, Ivan; Chiu, Weihsueh A.; Lash, Lawrence H.; Kromhout, Hans; Hansen, Johnni; Guyton, Kathryn Z.

    2014-01-01

    The chlorinated solvent trichloroethylene (TCE) is a ubiquitous environmental pollutant. The carcinogenic hazard of TCE was the subject of a 2012 evaluation by a Working Group of the International Agency for Research on Cancer (IARC). Information on exposures, relevant data from epidemiologic studie

  17. IARC Monographs: 40 Years of Evaluating Carcinogenic Hazards to Humans

    NARCIS (Netherlands)

    Pearce, Neil E; Blair, Aaron; Vineis, Paolo; Ahrens, Wolfgang; Andersen, Aage; Anto, Josep M; Armstrong, Bruce K; Baccarelli, Andrea A; Beland, Frederick A; Berrington, Amy; Bertazzi, Pier A; Birnbaum, Linda S; Brownson, Ross C; Bucher, John R; Cantor, Kenneth P; Cardis, Elisabeth; Cherrie, John W; Christiani, David C; Cocco, Pierluigi; Coggon, David; Comba, Pietro; Demers, Paul A; Dement, John M; Douwes, Jeroen; Eisen, Ellen A; Engel, Lawrence S; Fenske, Richard A; Fleming, Lora E; Fletcher, Tony; Fontham, Elizabeth; Forastiere, Francesco; Frentzel-Beyme, Rainer; Fritschi, Lin; Gerin, Michel; Goldberg, Marcel; Grandjean, Philippe; Grimsrud, Tom K; Gustavsson, Per; Haines, Andy; Hartge, Patricia; Hansen, Johnni; Hauptmann, Michael; Heederik, Dick; Hemminki, Kari; Hemon, Denis; Hertz-Picciotto, Irva; Hoppin, Jane A; Huff, James; Jarvholm, Bengt; Kang, Daehee; Karagas, Margaret R; Kjaerheim, Kristina; Kjuus, Helge; Kogevinas, Manolis; Kriebel, David; Kristensen, Petter; Kromhout, Hans; Laden, Francine; Lebailly, Pierre; LeMasters, Grace; Lubin, Jay H; Lynch, Charles F; Lynge, Elsebeth; 't Mannetje, Andrea; McMichael, Anthony J; McLaughlin, John R; Marrett, Loraine; Martuzzi, Marco; Merchant, James A; Merler, Enzo; Merletti, Franco; Miller, Anthony; Mirer, Franklin E; Monson, Richard; Nordby, Karl-Kristian; Olshan, Andrew F; Parent, Marie-Elise; Perera, Frederica P; Perry, Melissa J; Pesatori, Angela C; Pirastu, Roberta; Porta, Miquel; Pukkala, Eero; Rice, Carol; Richardson, David B; Ritter, Leonard; Ritz, Beate; Ronckers, Cecile M; Rushton, Lesley; Rusiecki, Jennifer A; Rusyn, Ivan; Samet, Jonathan M; Sandler, Dale P; de Sanjose, Silvia; Schernhammer, Eva; Seniori Constantini, Adele; Seixas, Noah; Shy, Carl; Siemiatycki, Jack; Silvermann, Debra T; Simonato, Lorenzo; Smith, Allan H; Smith, Martyn T; Spinelli, John J; Spitz, Margaret R; Stallones, Lorann; Stayner, Leslie T; Steenland, Kyle; Stenzel, Mark; Stewart, Bernard W; Stewart, Patricia A; Symanski, Elaine; Terracini, Benedetto; Tolbert, Paige E; Vainio, Harri; Vena, John; Vermeulen, Roel; Victora, Cesar G; Ward, Elizabeth M; Weinberg, Clarice R; Weisenburger, Dennis; Wesseling, Catharina; Weiderpass, Elisabete; Zahm, Shelia H

    2015-01-01

    BACKGROUND: Recently the International Agency for Research on Cancer (IARC) Programme for the Evaluation of Carcinogenic Risks to Humans has been criticized for several of its evaluations, and also the approach used to perform these evaluations. Some critics have claimed that IARC Working Groups' fa

  18. Non—Genotoxic Carcinogens.Approaches to Their Rish Assessment

    Institute of Scientific and Technical Information of China (English)

    J.A.CASTRO; M.I.DiazGomez; 等

    1993-01-01

    Epidemiological studies support the idea that most human cancers are related to chemicals present in the human environment.In turn,chemicals are believed to cause cancer via either genotoxic or non-genotoxic mechanisms.There were described in literature several simple rapid and inexpensive short term ests to reasonably predict the genotoxic nature of chemicals but in contrast,there is no reliable test or battery of tests available to predict the carcinogenicity of non-genotoxic compounds and this poses a major problem to their rish assessment.In addition,there are conflictive opinions about rish assessment needs for both classes of carcinogens.Some workers elieve that for non-genotoxic carcinogens,thresholds for exposure can be drawn while others do not.In this review,the reasons behind both of these opinions and the present hypotheses about the mechanism of action of non-genotoxic carcinogens are described and analyzed in relation to future needs.

  19. 18. Adduct detection in human monitoring for carcinogen exposure

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@Determination of the covalently bound products (adducts) of carcinogens with DNA or proteins may be used for the monitoring of exposure to these compounds. Protein adducts are generally stable and are not enzymatically repaired, and the use of these for cxposure monitoring is normally carried out with globin or albumin, because

  20. Characterization of UV radiation sensitive frog cell lines

    International Nuclear Information System (INIS)

    Twenty-one subclones of nine frog cell isolates were tested for sensitivity to a panel of DNA damaging agents. Two clones were identified which had a greater than wild type level of sensitivity to UV radiation but had a wild type level of sensitivity to the other agents. These clones were the haploid RRP602-7 and the diploid RRP802-1. RRP802-1 was found to be unstable with respect to UV sensitivity. The line was cloned in order to isolate stable sensitive and wild type derivatives. RRP802-1-16, a UV sensitive clone and RRP802-1-13, a clone with a wild type level of sensitivity to UV radiation, were isolated. The UV radiation sensitivity of RRP602-7, RRP802-1 and RRP802-1-16 did not correlate with cell size, cell shape, cell cycle distribution or ploidy. The cell cycle distribution after UV irradiation, the rate of DNA synthesis after UV-irradiation, the DNA polymerase α activity and the sister chromatid exchange frequency were all measured in RRP602-7, RRP802-1 and RRP802-1-16 in order to examine the DNA repair capacity. The presence of DNA repair pathways was examined directly in RRP602-7, RRP802-1 and RRP802-1-16. All were found to be proficient in photo-reactivation repair and postreplication repair of UV elicited DNA damage

  1. Light Conversion and Scattering in UV Protective Textiles

    Directory of Open Access Journals (Sweden)

    Grancarić Ana Marija

    2014-12-01

    Full Text Available The primary cause of skin cancer is believed to be a long exposure to solar ultraviolet radiation (UV-R crossed with the amount of skin pigmentation in the population. It is believed that in childhood and adolescence 80% of UV-R gets absorbed, whilst in the remaining 20% gets absorbed later in the lifetime. This suggests that proper and early photoprotection may reduce the risk of subsequent occurrence of skin cancer. Textile and clothing are the most suitable interface between environment and human body. It can show UV protection, but in most cases it does not provide full sun screening properties. UV protection ability highly depends on large number of factors such as type of fibre, fabric surface and construction, type and concentration of dyestuff, fluorescent whitening agent (FWA, UV-B protective agents, as well as nanoparticles, if applied. Based on electronically excited state by energy of UV-R (usually 340-370 nm, the molecules of FWAs show the phenomenon of fluorescence giving to white textiles high whiteness of outstanding brightness by reemitting the energy at the blue region (typically 420-470 nm of the spectrum. By absorbing UV-A radiation, optical brightened fabrics transform this radiation into blue fluorescence, which leads to better UV protection. Natural zeolites are rock-forming, microporous silicate minerals. Applied as nanoparticles to textile surface, it scatters the UV-R resulting in lower UV-A and UV-B transmission. If applied with other UV absorbing agents, e.g. FWAs, synergistic effect occurs. Silicones are inert, synthetic compounds with a variety of forms and uses. It provides a unique soft touch, is very resistant to washing and improves the property of fabric to protect against UV radiation. Therefore, the UV protective properties of cotton fabric achieved by light conversion and scattering was researched in this paper. For that purpose, the stilbene-derived FWAs were applied on cotton fabric in wide concentration

  2. Spectroscopic (FT-IR, FT-Raman, UV, 1H and 13C NMR) profiling and theoretical calculations of (2E)-2-[3-(1H-imidazol-1-yl)-1-phenylpropylidene]hydrazinecarboxamide: An anticonvulsant agent

    Science.gov (United States)

    Haress, Nadia G.; Govindarajan, Munusamy; AL-Wabli, Reem I.; Almutairi, Maha S.; Al-Alshaikh, Monirah A.; Al-Saadi, Abdulaziz A.; Attia, Mohamed I.

    2016-08-01

    Vibrational characteristics of the anticonvulsant agent, (2E)-2-[3-(1H-imidazol-1-yl)-1-phenylpropylidene]hydrazinecarboxamide ((2E)-IPHC) have been investigated. The computational data are obtained by adopting ab initio Hartree-Fock (HF) and DFT/B3LYP/6-31 + G(d,p) methods. The most stable conformer is identified by a potential energy scan. The optimized geometrical parameters indicated that the overall symmetry of the most stable conformer is CS. Atoms in molecules (AIM) analysis is contained out and the chemical bondings between the atoms are as characterized. Mulliken atomic charges and simulated thermo-molecular (heat capacity and enthalpy) characteristics of the (2E)-IPHC molecule also have been analyzed. The magnitude of the molecular electrostatic potential (MEP) of oxygen, hydrogen, and nitrogen atoms as well as phenyl and imidazole rings in the title molecule were investigated along with their contribution to the biological activity. The energy gap between HOMO and LUMO orbitals has been found to be 5.1334 eV in the gaseous phase. Excitation energies, oscillator strength and wavelengths were computed by the time-dependent density function theory (TD-DFT) approach. Predicted wavenumbers have been assigned and they are consistent with the experimental values. The 1H and 13C nuclear magnetic resonance (NMR) chemical shifts of the (2E)-IPHC molecule were computed by the gauge independent atomic orbital (GIAO) method and were compared with the experimental results.

  3. Risk assessment of DNA-reactive carcinogens in food

    International Nuclear Information System (INIS)

    Risk assessment of DNA-reactive carcinogens in food requires knowledge of the extent of DNA damage in the target organ which results from the competition between DNA adduct formation and repair. Estimates of DNA adduct levels can be made by direct measurement or indirectly as a consequence of their presence, for example, by tumor formation in animal models or exposed populations epidemiologically. Food-borne DNA-reactive carcinogens are present from a variety of sources. They are generally not intrinsically DNA-reactive but require bioactivation to DNA-reactive metabolites a process which may be modulated by the compound itself or the presence of other xenobiotics. A single DNA reactant may form several distinct DNA adducts each undergoing different rates of repair. Some DNA reactants may be photochemically activated or produce reactive oxygen species and thus indirect oxidative DNA damage. The levels of DNA adducts arising from exposures influenced by variations in the doses, the frequency with which an individual is exposed, and rates of DNA repair for specific adducts. Each adduct has a characteristic efficiency with which it induces mutations. Based on experience with the well-studied DNA-reactive food carcinogen aflatoxin B1 (AFB1), a limit of 20 ppb or ∼30 μg/day has been set and is considered a tolerable daily intake (TDI). Since AFB1 is considered a potent carcinogen, doses of 32P-postlabeling or the use of surrogates such as hemoglobin adducts, together with approaches to evaluate the results. A discussion of approaches to estimating possible threshold effects for DNA-reactive carcinogens is made

  4. Lactoperoxidase-catalyzed activation of carcinogenic aromatic and heterocyclic amines.

    Science.gov (United States)

    Gorlewska-Roberts, Katarzyna M; Teitel, Candee H; Lay, Jackson O; Roberts, Dean W; Kadlubar, Fred F

    2004-12-01

    Lactoperoxidase, an enzyme secreted from the human mammary gland, plays a host defensive role through antimicrobial activity. It has been implicated in mutagenic and carcinogenic activation in the human mammary gland. The potential role of heterocyclic and aromatic amines in the etiology of breast cancer led us to examination of the lactoperoxidase-catalyzed activation of the most commonly studied arylamine carcinogens: 2-amino-1-methyl-6-phenylimidazo[4,5-b]-pyridine (PhIP), benzidine, 4-aminobiphenyl (ABP), 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), and 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx). In vitro activation was performed with lactoperoxidase (partially purified from bovine milk or human milk) in the presence of hydrogen peroxide and calf thymus DNA. Products formed during enzymatic activation were monitored by HPLC with ultraviolet and radiometric detection. Two of these products were characterized as hydrazo and azo derivatives by means of mass spectrometry. The DNA binding level of 3H- and 14C-radiolabeled amines after peroxidase-catalyzed activation was dependent on the hydrogen peroxide concentration, and the highest levels of carcinogen binding to DNA were observed at 100 microM H2O2. Carcinogen activation and the level of binding to DNA were in the order of benzidine > ABP > IQ > MeIQx > PhIP. One of the ABP adducts was identified, and the level at which it is formed was estimated to be six adducts/10(5) nucleotides. The susceptibility of aromatic and heterocyclic amines for lactoperoxidase-catalyzed activation and the binding levels of activated products to DNA suggest a potential role of lactoperoxidase-catalyzed activation of carcinogens in the etiology of breast cancer.

  5. Population variability in biological adaptive responses to DNA damage and the shapes of carcinogen dose-response curves

    International Nuclear Information System (INIS)

    Carcinogen dose-response curves for both ionizing radiation and chemicals are typically assumed to be linear at environmentally relevant doses. This assumption is used to ensure protection of the public health in the absence of relevant dose-response data. A theoretical justification for the assumption has been provided by the argument that low dose linearity is expected when an exogenous agent adds to an ongoing endogenous process. Here, we use computational modeling to evaluate (1) how two biological adaptive processes, induction of DNA repair and cell cycle checkpoint control, may affect the shapes of dose-response curves for DNA-damaging carcinogens and (2) how the resulting dose-response behaviors may vary within a population. Each model incorporating an adaptive process was capable of generating not only monotonic dose-responses but also nonmonotonic (J-shaped) and threshold responses. Monte Carlo analysis suggested that all these dose-response behaviors could coexist within a population, as the spectrum of qualitative differences arose from quantitative changes in parameter values. While this analysis is largely theoretical, it suggests that (a) accurate prediction of the qualitative form of the dose-response requires a quantitative understanding of the mechanism (b) significant uncertainty is associated with human health risk prediction in the absence of such quantitative understanding and (c) a stronger experimental and regulatory focus on biological mechanisms and interindividual variability would allow flexibility in regulatory treatment of environmental carcinogens without compromising human health

  6. Carcinogenicity of oil shale tars, some of their components, and commercial products.

    Science.gov (United States)

    Bogovski, P A; Vinkmann, F

    1979-06-01

    Bioassays for carcinogenicity of various primary processing products (crude oils or tars) and commercial products obtained from Estorian oil shale have been carried out since 1951. The products (undiluted or diluted) were painted twice weekly 50 times on the interscapular area of the skin of random-bred or CC57Br mice. The products processed at high temperatures have a higher carcinogenic activity. Blends of products containing over 10% of high temperature crude oil (chamber furnace oil) have about the same carcinogenic activity as the latter. There is no strict correlation between the concentration of benzo(a)pyrene (BP) in oil shale products and their carcinogenic activity. Determination of BP in such products can serve as an approximate estimate of carcinogenic properties. The results of animal experiments with chromatographic fractions of the high temperature shale oil demonstrated the presence of compounds which lengthen the latency period of the carcinogenic effect of BP in the aromatic fraction of this oil as well as other carcinogens and compounds enhancing the activity of carcinogenic compounds. Under industrial conditions, contact of workers with carcinogenic shale oils can be reduced by means of coking the carcinogenic oils, which results in production of solid coke and of distillate which is recycled. Medical vaseline potentiates the carcinogenic action of BP and similar compounds. Dilution of shale oils with oils containing aliphatic hydrocarbons cannot be considered as diminution of the carcinogenic potency of these products. PMID:446447

  7. Disinfection of a wastewater flow treated by advanced primary treatment using O₃, UV and O₃/UV combinations.

    Science.gov (United States)

    Bustos, Yaneth A; Vaca, Mabel; López, Raymundo; Torres, Luis G

    2010-11-01

    This study was conducted to evaluate the ozone, UV and O₃/UV processes for the reuse of sewage treatment plant effluent (Universidad Autonoma Metropolitana Azcapotzalco wastewater treatment plant). The ozone/UV process was compared to individual ozone and the UV processes and control parameters were total and fecal coliforms. Different ozone concentrations (6-12 mg O₃/min) and different UV fluencies (6.7-20.12 mJ/cm²) were tested. It is possible to conclude than none of the processes achieved the disinfection levels required to comply with the Mexican standard NOM-003-SEMARNAT-1997. The continuous ozone process offered the lower total and fecal coliforms reductions, while UV light resulted a disinfection agent with higher germicide power than ozone. The maximum logarithmic reduction achieved due to the combined ozone/UV process was of 2.04 for fecal coliforms and of 2.17 for total coliforms. The next 8 combinations showed lower removal efficiencies, but always higher than those obtained with the single ozone or UV processes. The ozone/UV process was highly effective for the disinfection and a synergistic effect was observed.

  8. Photochemistry. Chemiexcitation of melanin derivatives induces DNA photoproducts long after UV exposure.

    Science.gov (United States)

    Premi, Sanjay; Wallisch, Silvia; Mano, Camila M; Weiner, Adam B; Bacchiocchi, Antonella; Wakamatsu, Kazumasa; Bechara, Etelvino J H; Halaban, Ruth; Douki, Thierry; Brash, Douglas E

    2015-02-20

    Mutations in sunlight-induced melanoma arise from cyclobutane pyrimidine dimers (CPDs), DNA photoproducts that are typically created picoseconds after an ultraviolet (UV) photon is absorbed at thymine or cytosine. We found that in melanocytes, CPDs are generated for >3 hours after exposure to UVA, a major component of the radiation in sunlight and in tanning beds. These "dark CPDs" constitute the majority of CPDs and include the cytosine-containing CPDs that initiate UV-signature C→T mutations. Dark CPDs arise when UV-induced reactive oxygen and nitrogen species combine to excite an electron in fragments of the pigment melanin. This creates a quantum triplet state that has the energy of a UV photon but induces CPDs by energy transfer to DNA in a radiation-independent manner. Melanin may thus be carcinogenic as well as protective against cancer. These findings also validate the long-standing suggestion that chemically generated excited electronic states are relevant to mammalian biology.

  9. [Carcinogenic N-nitrosamines in the tire industry].

    Science.gov (United States)

    Sokol?kaia, N N; Krivosheeva, L V; Khesing, A Ia; Piven, V A; Kavun, S M

    1993-01-01

    The level of volatile carcinogenic N-nitrosamines (NA) was studied in the air of various technological sites of tyre production. Reported total levels of NA in air exceeded MACs set in certain countries for the same enterprises. For example, German total MAC for 12 carcinogenic NA is 1 g/m3. N-nitrosomorpholine appeared to have the highest level (91 g/m3), probably, because its derivatives are used as raw material for technological process. Relative rate of volatile NA release from rubber samples containing 4-nitrosodiphenylamine (modifier) was studied. The parameter was reported to have no influence on NA outlet in conditions simulating technological process. NA was detected by means of gas chromatography with thermal energy detector TEA 502A provided by Thermo Electron Corporation, USA. The article necessitates regulation of NA in tyre production and better rubber mixtures to control the pollution of atmosphere. PMID:8069502

  10. 4-Dimethylaminoazobenzenes: carcinogenicities and reductive cleavage by microsomal azo reductase.

    Science.gov (United States)

    Lambooy, J P; Koffman, B M

    1985-01-01

    Twenty-four 4-dimethylaminoazobenzenes (DABs) in which systematic structural modifications have been made in the prime ring have been studied for substrate specificity for microsomal azo reductase. The DABs were also evaluated for carcinogenicity and it was found that there was no correlation between carcinogenicity and extent of azo bond cleavage by azo reductase. While any substituent in the prime ring reduces the rate of cleavage of the azo bond relative to the unsubstituted dye, there is a correlation between substituent size and susceptibility to the enzyme. Substituent size was also found to be a significant factor in the induction of hepatomas by the dyes. Preliminary studies have shown that there appears to be a positive correlation between microsomal riboflavin content and the activity of the azo reductase.

  11. uv photobiology: excision repair

    International Nuclear Information System (INIS)

    The following topics are discussed: steps in nucleotide excision; damage to DNA by uv-endonuclease; use of complementation to study DNA repair in Escherichia coli and mammalian cells; role of BUDR photolysis in excision repair, relation between DNA repair defect and human disease; base excision repair; and excision repair by removal of damaged region of a base in DNA without excision

  12. Some carcinogenic polycyclic aromatic hydrocarbons by photoacoustic spectroscopy

    Science.gov (United States)

    Garg, R. K.; Kumar, Pardeep; Ram, R. S.; Zaidi, Zahid H.

    1999-12-01

    Polycyclic aromatic hydrocarbons (PAHs) have attracted spectroscopists, astrophysicts and environmentalist because of their importance in our day to day life. It is well known that epoxides are produced during the metabolism of PAHs and have the requisite chemical reactivity to qualify them for the role as an ultimate carcinogenic form of PAHs. Several carcinogenic PAHs such as 3.4-benzopyrene, 1.2,3.4-dibenzopyrene, 3.4,9.10- dibenzopyrene etc. are found to be present in tobacco smoke and among air pollutants. Although PAH molecules are being studied for last several years by using conventional spectroscopy but no systematic attempt has been made to study non-radiative transitions. In our laboratory, we have studied many PAH molecules by a non-destructive technique with unique capability and sensitivity, known as Photoacoustic (PA) spectroscopy. PA spectroscopy is an analytical and research tool to get information about non-radiative transitions and singlet-triplet electronic transitions, where the conventional spectroscopic technique fails. The study of electronic transitions of some carcinogenic molecules are reported using PA and optical absorption spectra in boric acid glass in the region 250 - 400 nm. The electronic transitions of these molecules observed experimentally, have been interpreted using the optimized geometries and CNDO/S-CI method. A good agreement is found between the experimental and calculated results. Assignments of observed electronic transitions are made on the basis of singlet-triplet electronic transitions. Vibrations attached to these electronic transitions are attributed to the ground state vibrational modes.

  13. Linearity of dose-response relationships for human carcinogenic exposures

    Energy Technology Data Exchange (ETDEWEB)

    Smith, A.H. (Univ. of California, Berkeley (USA))

    The shape of dose-response relationships is a critical factor in considering cancer risks for the work place and environmental exposure to carcinogens. Markedly different risk estimates result from assumptions of linearity versus sublinear and threshold assumptions. This paper presents evidence that the relationship between the relative risk of development of cancer and the dose rate to carcinogenic exposures is frequently linear with no evidence for thresholds. Dose-response relationships from four studies of asbestos and lung cancer were examined, all of which were consistent with a linear relationship. Analysis of the relationship between the relative risk of lung cancer and exposure to nickel in a smelter study, selected because of relatively good exposure data, demonstrated a close agreement with a linear relationship. The relationship between the level of arsenic in drinking wter and the prevalence of skin cancer also was linear for males in the highest prevalence age group in Taiwan, although there was some evidence of sublinearity for females and younger persons. Also, the relationships between the number of cigarettes smoked per day and the relative risk of lung cancer was very close to linear in many studies. The analysis of these and other studies involving human exposure to carcinogens provides empirical evidence for linearity when the response variable is a rate ratio measure, rather than a risk difference measure. Linearity in dose-response is biologically plausible, without invoking a one-hit model. Except in special circumstances. the epidemiological evidence supports linear extrapolation of cancer relative risks.

  14. Artificial sweeteners--do they bear a carcinogenic risk?

    Science.gov (United States)

    Weihrauch, M R; Diehl, V

    2004-10-01

    Artificial sweeteners are added to a wide variety of food, drinks, drugs and hygiene products. Since their introduction, the mass media have reported about potential cancer risks, which has contributed to undermine the public's sense of security. It can be assumed that every citizen of Western countries uses artificial sweeteners, knowingly or not. A cancer-inducing activity of one of these substances would mean a health risk to an entire population. We performed several PubMed searches of the National Library of Medicine for articles in English about artificial sweeteners. These articles included 'first generation' sweeteners such as saccharin, cyclamate and aspartame, as well as 'new generation' sweeteners such as acesulfame-K, sucralose, alitame and neotame. Epidemiological studies in humans did not find the bladder cancer-inducing effects of saccharin and cyclamate that had been reported from animal studies in rats. Despite some rather unscientific assumptions, there is no evidence that aspartame is carcinogenic. Case-control studies showed an elevated relative risk of 1.3 for heavy artificial sweetener use (no specific substances specified) of >1.7 g/day. For new generation sweeteners, it is too early to establish any epidemiological evidence about possible carcinogenic risks. As many artificial sweeteners are combined in today's products, the carcinogenic risk of a single substance is difficult to assess. However, according to the current literature, the possible risk of artificial sweeteners to induce cancer seems to be negligible. PMID:15367404

  15. Carcinogenicity of azo colorants: influence of solubility and bioavailability.

    Science.gov (United States)

    Golka, Klaus; Kopps, Silke; Myslak, Zdislaw W

    2004-06-15

    In the past, azo colorants based on benzidine, 3,3'-dichlorobenzidine, 3,3'-dimethylbenzidine (o-tolidine), and 3,3'-dimethoxybenzidine (o-dianisidine) have been synthesized in large amounts and numbers. Studies in exposed workers have demonstrated that the azoreduction of benzidine-based dyes occurs in man. The metabolic conversion of benzidine-, 3,3'-dimethylbenzidine- and 3,3'-dimethoxybenzidine-based dyes to their (carcinogenic) amine precursors in vivo is a general phenomenon that must be considered for each member of this class of chemicals. Several epidemiological studies have demonstrated that the use of the benzidine-based dyes has caused bladder cancer in humans. However, in contrast to water-soluble dyes, the question of biological azoreduction of (practically insoluble) pigments has been a matter of discussion. As a majority of azo pigments are based on 3,3'-dichlorobenzidine, much of the available experimental data are focused on this group. Long-term animal carcinogenicity studies performed with pigments based on 3,3'-dichlorobenzidine did not show a carcinogenic effect. The absence of a genotoxic effect has been supported by mutagenicity studies with the 3,3'-dichlorobenzidine-based Pigment Yellow 12. Studies in which azo pigments based on 3,3'-dichlorobenzidine had been orally administered to rats, hamsters, rabbits and monkeys could generally not detect significant amounts of 3,3'-dichlorobenzidine in the urine. It, therefore, appears well established that the aromatic amine components from azo pigments based on 3,3'-dichlorobenzidine are practically not bioavailable. Hence, it is very unlikely that occupational exposure to insoluble azo pigments would be associated with a substantial risk of (bladder) cancer in man. According to current EU regulations, azo dyes based on benzidine, 3,3'-dimethoxybenzidine and 3,3'-dimethylbenzidine have been classified as carcinogens of category 2 as "substances which should be regarded as if they are carcinogenic

  16. Antibiotic Agents

    Science.gov (United States)

    ... either as public health or as non-public health antimicrobial agents. What is the difference between bacteriostats, sanitizers, disinfectants ... bacteria, however, there is considerable controversy surrounding their health benefits. The ... producing agents (Table of Antibacterials) have been used for many ...

  17. Morphological transformation and effect on gap junction intercellular communication in Syrian hamster embryo cells as screening tests for carcinogens devoid of mutagenic activity.

    Science.gov (United States)

    Rivedal, E; Mikalsen, S O; Sanner, T

    2000-04-01

    A large fraction of chemicals observed to cause cancer in experimental animals is devoid of mutagenic activity. It is therefore of importance to develop methods that can be used to detect and study environmental carcinogenic agents that do not interact directly with DNA. Previous studies have indicated that induction of in vitro cell transformation and inhibition of gap junction intercellular communication are endpoints that could be useful for the detection of non-genotoxic carcinogens. In the present work, 13 compounds [chlordane, Arochlor 1260, di(2-ethylhexyl)phthalate, 1,1,1-trichloro-2, 2-bis(4-chlorophenyl)ethane, limonene, sodium fluoride, ethionine, o-anisidine, benzoyl peroxide, o-vanadate, phenobarbital, 12-O-tetradecanoylphorbol 13-acetate and clofibrate] have been tested for their ability to induce morphological transformation and affect intercellular communication in Syrian hamster embryo cells. The substances were selected on the basis of being proven or suspected non-genotoxic carcinogens, and thus difficult to detect in short-term tests. The data show that nine of the 13 compounds induced morphological transformation, and seven of the 13 inhibited intercellular communication in hamster embryo cells. Taken together, 12 of the 13 substances either induced transformation or caused inhibition of communication. The data suggest that the combined use of morphological transformation and gap junction intercellular communication in Syrian hamster embryo cells may be beneficial when screening for non-genotoxic carcinogens. PMID:10793297

  18. Aflatoxin is not a probably human carcinogen: the published evidence is sufficient.

    Science.gov (United States)

    Stoloff, L

    1989-12-01

    infection for aflatoxin could not be ruled out. However, the epidemiological studies of the HBV/PLC relation indicate that an accessory factor is not an essential condition, a conclusion supported by animal models and a laboratory study that specifically found no interaction between aflatoxin and a hepatitis virus in the duck, a species in which liver cancer can be induced by either agent. It was surprising that an IARC Working Group meeting in 1987 concluded, on the basis of much of this evidence that was available at that time, and citing other studies that appear to be irrelevant to the issue, that there was sufficient evidence to consider aflatoxin a probable human carcinogen.

  19. Degradation of antipyrine by UV, UV/H2O2 and UV/PS

    International Nuclear Information System (INIS)

    Highlights: • The antipyrine decomposition exhibited a pseudo-first-order kinetics pattern well. • The kobs with irradiance or oxidant dosage presented a linear relationship well. • The kobs exhibit an exponential trend as a function of [AP]0 for three systems. • UV/H2O2 behaved best at pH 2.5–10, while UV/PS behaved best at pH 10.0–11.5. • Cost for chemicals was firstly taken into account in calculation of the EE/O values. -- Abstract: Degradation of antipyrine (AP) in water by three UV-based photolysis processes (i.e., direct UV, UV/H2O2, UV/persulfate (UV/PS)) was studied. For all the oxidation processes, the AP decomposition exhibited a pseudo-first-order kinetics pattern. Generally, UV/H2O2 and UV/PS significantly improved the degradation rate relevant to UV treatment alone. The pseudo-first-order degradation rate constants (kobs) were, to different degrees, affected by initial AP concentration, oxidant dose, pH, UV irradiation intensity, and co-existing chemicals such as humic acid, chloride, bicarbonate, carbonate and nitrate. The three oxidation processes followed the order in terms of treatment costs: UV/PS > UV > UV/H2O2 if the energy and chemical costs are considered. Finally, the AP degradation pathways in the UV/H2O2 and UV/PS processes are proposed. Results demonstrated that UV/H2O2 and UV/PS are potential alternatives to control water pollution caused by emerging contaminants such as AP

  20. Coal fires, industrial emissions and motor vehicles as sources of environmental carcinogens.

    Science.gov (United States)

    Lawther, P J; Waller, R E

    1976-01-01

    One of the most widely studied carcinogenic agents in the environment is the polycyclic hydrocarbon, benzo(a) pyrene. As a component of soot from the inefficient combustion of coal, its association with cancer can be traced back 200 years, but its possible relevance to lung cancer as a widely distributed air relevance to lung cancer as a widely distributed air pollutant has been investigated only during the past 25 years. Domestic coal fires have been shown to be important sources, and smaller amounts come from industrial sources and from motor vehicles. There is evidence now that the concentration of benzo (a) pyrene in large towns in Britain has decreased by a factor of about ten during the last few decades, as a result of changing heating methods and smoke control. In view of the overwhelming effect of cigarette smoking, it is difficult to determine whether the benzo(a)pyrene content of the air has had any importnat effect on the development of lung cancer, but careful analysis of trends in mortality may now throw some light on this. Among other materials with carcinogenic properties that may be dispersed into the general air, asbestos is the one that has been investigated most thoroughly. The association between exposure to asbestos and the development of lung cancer and mesothelioma of the pleura has been clearly demonstrated among people occupationally exposed to the dust, but as far as the general public is concerned, any risk may be limited to the immediate vicinity of major sources. These and other hazards demonstrated among occupational gropus serve as a warning however to maintain careful scutiny of urban air pollutants in relation to the acetiology of cancer.

  1. Neoplastic transformation of human breast epithelial cells by estrogens and chemical carcinogens.

    Science.gov (United States)

    Russo, Jose; Tahin, Quivo; Lareef, M Hasan; Hu, Yun-Fu; Russo, Irma H

    2002-01-01

    Sporadic breast cancer, the most common cancer diagnosed in American and Northern European women, is gradually increasing in incidence in most Western countries. Prevention would be the most efficient way of eradicating this disease. This goal, however, cannot be accomplished until the specific agent(s) or mechanisms that initiate the neoplastic process are identified. Experimental studies have demonstrated that mammary cancer is a hormone-dependent multistep process that can be induced by a variety of compounds and mechanisms, that is, hormones, chemicals, radiation, and viruses, in addition to or in combination with genetic factors. Although estrogens have been shown to play a central role in breast cancer development, their carcinogenicity on human breast epithelial cells (HBECs) has not yet been clearly demonstrated. Breast cancer initiates in the undifferentiated lobules type 1, which are composed of three cell types: highly proliferating cells that are estrogen-receptor negative (ER-), nonproliferating cells that are ER positive (ER+), and very few (17p13.2. The relevance of these findings is highlighted by the observation that E(2)- and B[a]P-induced genomic alterations in the same loci found in ductal hyperplasia, ductal carcinoma in situ, and invasive ductal carcinoma of the breast. PMID:11921196

  2. Appraisal of alternative skin model for the study of epidermal restoration following exposure to various environmental stress agents: ionising radiation and UV B; Evaluation d'un modele alternatif de peau dans l'etude de l'atteinte epidermique apres exposition a differents agents de stress environnementaux: rayonnements ionisants (RI) et ultra-violets B (UVB)

    Energy Technology Data Exchange (ETDEWEB)

    Isoir, M

    2006-06-15

    Human skin is a major target tissue for ionising radiation (IR) and UV B. We developed a skin explant model and used 2 types of keratinocytes to study survival and oxidative stress induced by these radiations. We examined oxidative damages by measuring R.O.S. produced and cellular anti-oxidant defenses induced. We observed into skin exposed to IR a modulation of genes expression implied in the control of oxidative stress, confirmed by the decrease of catalase, glutathione peroxidase and superoxide dismutase enzymatic activities. The imbalance observed between anti- and pro-apoptotic genes expression shows that keratinocytes apoptosis may be partly dependent on radio-induced R.O.S. production. We showed the difference of radiosensitivity between N.H.E.K. and Ha Ca.T., which may be linked to their differential oxidative responses. In addition, during re-epithelialising, we demonstrated that activated N.H.E.K. after IR express keratin 6, release pro-inflammatory cytokines and proliferate, without modification of their differentiation. Treatment of N.H.E.K. with geranyl geranylacetone (G.G.A.) has a beneficial effect on their radio-induced activation by increasing IL-1 release, their migration in scrapped area and their survival. G.G.A. has an anti apoptotic ability (induction of Hsp70- caspase-3 pathway) and migratory properties (P38/RhoA activation) on N.H.E.K., but after IR, only caspase-3 pathway is induced. This work thus contributes to the understanding of cutaneous damages after IR and G.G.A. mechanism of action which accelerates re-epithelialising. (author)

  3. Unanticipated role of melanin in causing carcinogenic cyclobutane pyrimidine dimmers.

    Science.gov (United States)

    Premi, Sanjay; Brash, Douglas E

    2016-01-01

    Ultraviolet radiation (UVR) instantaneously generates cyclobutane pyrimidine dimers (CPDs). Paradoxically, we recently observed that UV enables the protective pigment melanin to create CPDs in the dark long after the exposure ends. UV-induced reactive oxygen species (ROS) oxidize melanin to create melanin carbonyls in a high-energy quantum state. These energetic melanin carbonyls transfer their energy to DNA in the dark, creating CPDs in the absence of UVR. PMID:27308551

  4. Unanticipated role of melanin in causing carcinogenic cyclobutane pyrimidine dimmers

    OpenAIRE

    Premi, Sanjay; Brash, Douglas E.

    2015-01-01

    Ultraviolet radiation (UVR) instantaneously generates cyclobutane pyrimidine dimers (CPDs). Paradoxically, we recently observed that UV enables the protective pigment melanin to create CPDs in the dark long after the exposure ends. UV-induced reactive oxygen species (ROS) oxidize melanin to create melanin carbonyls in a high-energy quantum state. These energetic melanin carbonyls transfer their energy to DNA in the dark, creating CPDs in the absence of UVR.

  5. Estimated UV doses to psoriasis patients during climate therapy at Gran Canaria in March 2006

    Directory of Open Access Journals (Sweden)

    L. T. N. Nilsen

    2008-01-01

    Full Text Available Psoriasis is a chronic inflammatory disease involving about 2–3% of the Norwegian population. Sun exposure has a positive effect on most psoriasis lesions, but ultraviolet (UV radiation also causes a direct DNA damage in the skin cells and comprises a carcinogenic potential. UV exposure on the skin causes a local as well as a systemic immune suppressive effect, but the relation between sun exposure and these biological effects is not well known. In March 2006 a study was carried out to investigate possible therapeutic outcome mechanisms in 20 psoriasis patients receiving climate therapy at Gran Canaria. This paper presents estimates of their individual skin UV-doses based on UV measurements and the patients' diaries with information on time spent in the sun.

    On the first day of exposure the patients received on average 5.1 Standard Erythema Doses (SED: median=4.0 SED, range 2.6–10.3 SED estimated to the skin. During the 15 days study they received 165.8 SED (range 104.3–210.1 SED. The reduction in PASI score was 72.8% on average, but there was no obvious relation between the improvement and the UV dose. The UV doses were higher than those found from climate therapy studies at other locations. It seems beneficial to use more strict exposure schedules that consider the available UV irradiance, depending on time of the day, time of the year and weather conditions.

  6. Vaccinia virus, herpes simplex virus, and carcinogens induce DNA amplification in a human cell line and support replication of a helpervirus dependent parvovirus

    Energy Technology Data Exchange (ETDEWEB)

    Schlehofer, J.R.; Ehrbar, M.; zur Hausen, H.

    1986-07-15

    The SV40-transformed human kidney cell line, NB-E, amplifies integrated as well as episomal SV40 DNA upon treatment with chemical (DMBA) or physical (uv irradiation) carcinogens (initiators) as well as after infection with herpes simplex virus (HSV) type 1 or with vaccinia virus. In addition it is shown that vaccinia virus induces SV40 DNA amplification also in the SV40-transformed Chinese hamster embryo cell line, CO631. These findings demonstrate that human cells similar to Chinese hamster cells amplify integrated DNA sequences after treatment with carcinogens or infection with specific viruses. Furthermore, a poxvirus--vaccinia virus--similar to herpes group viruses induces DNA amplification. As reported for other systems, the vaccinia virus-induced DNA amplification in NB-E cells is inhibited by coinfection with adeno-associated virus (AAV) type 5. This is in line with previous studies on inhibition of carcinogen- or HSV-induced DNA amplification in CO631 cells. The experiments also demonstrate that vaccinia virus, in addition to herpes and adenoviruses acts as a helper virus for replication and structural antigen synthesis of AAV-5 in NB-E cells.

  7. Vaccinia virus, herpes simplex virus, and carcinogens induce DNA amplification in a human cell line and support replication of a helpervirus dependent parvovirus

    International Nuclear Information System (INIS)

    The SV40-transformed human kidney cell line, NB-E, amplifies integrated as well as episomal SV40 DNA upon treatment with chemical (DMBA) or physical (uv irradiation) carcinogens (initiators) as well as after infection with herpes simplex virus (HSV) type 1 or with vaccinia virus. In addition it is shown that vaccinia virus induces SV40 DNA amplification also in the SV40-transformed Chinese hamster embryo cell line, CO631. These findings demonstrate that human cells similar to Chinese hamster cells amplify integrated DNA sequences after treatment with carcinogens or infection with specific viruses. Furthermore, a poxvirus--vaccinia virus--similar to herpes group viruses induces DNA amplification. As reported for other systems, the vaccinia virus-induced DNA amplification in NB-E cells is inhibited by coinfection with adeno-associated virus (AAV) type 5. This is in line with previous studies on inhibition of carcinogen- or HSV-induced DNA amplification in CO631 cells. The experiments also demonstrate that vaccinia virus, in addition to herpes and adenoviruses acts as a helper virus for replication and structural antigen synthesis of AAV-5 in NB-E cells

  8. Results of screening NCI/NTP nongenotoxic carcinogens and genotoxic noncarcinogens with the ke test

    International Nuclear Information System (INIS)

    The interdependence of the electrophilic and carcinogenic properties of chemicals that was demonstrated two decades ago rekindled interest in the somatic mutation theory of carcinogenesis. Interest in this theory grew with the development of a reverse-mutation bacterial assay in the laboratory of B.N. Ames that permitted the mutagenic properties of the chemicals to be determined quickly and yielded results which indicated that ''carcinogens are mutagens.'' Subsequent validation studies of this bioassay, the Salmonella typhimurium/microsome or ''Ames test,'' by Ames' group and others provided additional support for the correlation between mutagenicity and carcinogenicity which led to the worldwide deployment of the Ames test in thousands of laboratories and to the development of more than 100 other short-term tests that continue to be used to identify potential carcinogens via various end-points of genotoxicity. This document discusses electrophilicity, mutagenicity, and carcinogenicity relationships as well as carcinogen-screening of chemicals. 28 refs., 4 tabs

  9. Prevention of cancer and the dose-effect relationship: the carcinogenic effects of ionizing radiations

    International Nuclear Information System (INIS)

    seldom occur. Promoting factors are agents that either perturb intercellular signalling or stimulate cell proliferation (e.g. hormones) or increase cell mortality: mechanical or chemical irritation (e.g. alcohol, bacteria, viruses) thereby inducing compensatory cell proliferation. Thus, gradually pre-cancerous cells become able to divide more rapidly with greater autonomy. This phase ends when a sub clone of cells has acquired the capacity of autonomous proliferation. The third phase is that of progression during which cells proliferate regularly without any stimulation. In one of the cells of one of the pre-cancerous lesions (e.g. polyps) a cell acquires the capacity of invading surrounding tissue or to metastasize. The whole carcinogenic process is very slow, extending over several decades, because the specific mutations seldom occur and the probability of an accumulation of several specific mutations in the same cell or cell lineage is very small. It can be accelerated by intense stimulation of cell proliferation or genetic instability. Ionizing radiations act firstly as a mutagen, however when the dose is high they also kill a significant proportion of cells and by a homeostatic mechanism they induce cell proliferation and clonal amplification. It has been claimed that even the smallest dose of radiation can induce a cancer. This concept is associated with the L.N.T. model and it is not based on scientific evidence. It has fuelled a fear of radiation which had detrimental consequences. Conversely the high efficacy of defense mechanisms against radio carcinogenesis, particularly when the tissue is not disorganized, can explain the lack of carcinogenic effect of contamination by small doses of radium or thorium which has been observed on radium dial painters or in patients injected with thorotrast. The study of second cancers in patients treated by radiotherapy could provide important information and should be actively pursued with two aims: reduce the incidence of

  10. Joint action of a chemical carcinogen and a neoplastic virus to induce cancer in rabbits; results of exposing epidermal cells to a carcinogenic hydrocarbon at time of infection with the Shope papilloma virus.

    Science.gov (United States)

    ROGERS, S; ROUS, P

    1951-05-01

    Areas of rabbit skin previously rendered hyperplastic with turpentine were scarified, inoculated with the Shope papilloma virus, and covered with a dressing that contained 20-methylcholanthrene (MC) or 9:10-dimethyl-1:2-benzanthracene (9:10). The dressing was left on until healing had been well completed, a matter of 5 to 7 days. The papillomas which subsequently arose often appeared later, were fewer, and remained less vigorous than those due to the action of virus alone, but throughout several months they appeared to differ from these in no other ways. Then, more or less abruptly, the large majority became carcinomatous, frequently at several situations, whereas with few exceptions the control growths underwent no such alteration. The cancers were of the sorts ordinarily deriving, by secondary change, from epidermal cells infected with the virus. Collateral data have made plain that the hydrocarbons acted in their carcinogenic capacity to bring on the cancers. Indeed in control tests 9: 10 sometimes conferred latent neoplastic potentialities on uninoculated epidermis exposed to it while healing after scarification, a fact disclosed months later by painting these expanses with chloroform until hyperplasia occurred. Under the promoting influence of this agent papillomas formed which had the distinctive morphology of those induced by the chemical carcinogens. So strong and enduring were the effects of MC and 9:10 as to cause cancers to arise from many virus papillomas which were retrogressing after months of proliferation, that is to say under circumstances ordinarily unfavorable to malignant change. The facts justify the conclusion that the virus and the hydrocarbons acted jointly and in their carcinogenic capacities. PMID:14832395

  11. KEYNOTE LECTURES-KL1 New development in risk assessment of genotoxic carcinogens in foods

    Institute of Scientific and Technical Information of China (English)

    CHEN Jun-Shi

    2006-01-01

    @@ The no-observed-effect level (NOEL) in a study of carcinogenicity for compounds that are both genotoxic and carcinogenic represents the limit of detection in that bioassay, rather than an estimate of a possible threshold. Therefore, for those genotoxic and carcinogenic contaminants (e.g. acrylamides, PAHs, etc.) in foods it is not possible to develop health-based guidance values (e.g. ADI or PTWI) using the traditional NOEL and safety/uncertainty factors.

  12. Discrimination of Carcinogens by Hepatic Transcript Profiling in Rats Following 28-day Administration

    Directory of Open Access Journals (Sweden)

    Hiroshi Matsumoto

    2009-11-01

    Full Text Available This study aimed at discriminating carcinogens on the basis of hepatic transcript profiling in the rats administrated with a variety of carcinogens and non-carcinogens. We conducted 28-day toxicity tests in male F344 rats with 47 carcinogens and 26 non- carcinogens, and then investigated periodically the hepatic gene expression profiles using custom microarrays. By hierarchical cluster analysis based on significantly altered genes, carcinogens were clustered into three major groups (Group 1 to 3. The formation of these groups was not affected by the gene sets used as well as the administration period, indicating that the grouping of carcinogens was universal independent of the conditions of both statistical analysis and toxicity testing. Seventeen carcinogens belonging to Group 1 were composed of mainly rat hepatocarcinogens, most of them being mutagenic ones. Group 2 was formed by three subgroups, which were composed of 23 carcinogens exhibiting distinct properties in terms of genotoxicity and target tissues, namely nonmutagenic hepatocarcinogens, and mutagenic and nonmutagenic carcinogens both of which are targeted to other tissues. Group 3 contained 6 carcinogens including 4 estrogenic substances, implying the group of estrogenic carcinogens. Gene network analyses revealed that the significantly altered genes in Group 1 included Bax, Tnfrsf6, Btg2, Mgmt and Abcb1b, suggesting that p53-mediated signaling pathway involved in early pathologic alterations associated with preceding mutagenic carcinogenesis. Thus, the common transcriptional signatures for each group might reflect the early molecular events of carcinogenesis and hence would enable us to identify the biomarker genes, and then to develop a new assay for carcinogenesis prediction.

  13. Carcinogenic effects of circadian disruption: an epigenetic viewpoint.

    Science.gov (United States)

    Salavaty, Abbas

    2015-08-08

    Circadian rhythms refer to the endogenous rhythms that are generated to synchronize physiology and behavior with 24-h environmental cues. These rhythms are regulated by both external cues and molecular clock mechanisms in almost all cells. Disruption of circadian rhythms, which is called circadian disruption, affects many biological processes within the body and results in different long-term diseases, including cancer. Circadian regulatory pathways result in rhythmic epigenetic modifications and the formation of circadian epigenomes. Aberrant epigenetic modifications, such as hypermethylation, due to circadian disruption may be involved in the transformation of normal cells into cancer cells. Several studies have indicated an epigenetic basis for the carcinogenic effects of circadian disruption. In this review, I first discuss some of the circadian genes and regulatory proteins. Then, I summarize the current evidence related to the epigenetic modifications that result in circadian disruption. In addition, I explain the carcinogenic effects of circadian disruption and highlight its potential role in different human cancers using an epigenetic viewpoint. Finally, the importance of chronotherapy in cancer treatment is highlighted.

  14. Formaldehyde in dentistry: a review of mutagenic and carcinogenic potential

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, B.B.; Chestner, S.B.

    1981-09-01

    For many years there has been controversy over the value of antimicrobial drugs for intracanal dressings in endodontics. Formocresol, a formaldehyde compound, has evolved as the preferred drug for routine endodontic procedures, as well as pediatric endodontics. The increase in the use of formaldehyde has been complicated by the introduction of paraformaldehyde pastes for filling root canals. Neither of these formulas has ever been standardized. The doses are arbitrary, and the common dose of formocresol has been shown to be many times greater than the minimum dose needed for effect. The efficacy of paraformaldehyde pastes is questionable and remains clouded by inconclusive evidence, conflicting research, inadequate terminology, and a lack of convincing statistical evidence. The clinical use and delivery of formocresol and paraformaldehyde pastes remain arbitrary and unscientific. Formaldehyde has a known toxic mutagenic and carcinogenic potential. Many investigations have been conducted to measure the risk of exposure to formaldehyde; it is clear that formaldehyde poses a carcinogenic risk in humans. There is a need to reevaluate the rationale underlying the use of formaldehyde in dentistry particularly in light of its deleterious effects.

  15. Carcinogenic effects ofcircadian disruption:an epigenetic viewpoint

    Institute of Scientific and Technical Information of China (English)

    Abbas Salavaty

    2015-01-01

    Circadian rhythms refer to the endogenous rhythms that are generated to synchronize physiology and behavior with 24-h environmental cues. These rhythms are regulated by both external cues and molecular clock mechanisms in almost all cells. Disruption of circadian rhythms, which is called circadian disruption, affects many biological processes within the body and results in different long-term diseases, including cancer. Circadian regulatory pathways result in rhythmic epigenetic modiifcations and the formation of circadian epigenomes. Aberrant epigenetic modiifcations, such as hypermethylation, due to circadian disruption may be involved in the transformation of normal cells into cancer cells. Several studies have indicated an epigenetic basis for the carcinogenic effects of circadian disruption. In this review, I ifrst discuss some of the circadian genes and regulatory proteins. Then, I summarize the current evidence related to the epigenetic modiifcations that result in circadian disruption. In addition, I explain the carcinogenic effects of circadian disruption and highlight its potential role in different human cancers using an epigenetic view-point. Finally, the importance of chronotherapy in cancer treatment is highlighted.

  16. Predicting carcinogenicity of diverse chemicals using probabilistic neural network modeling approaches

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Kunwar P., E-mail: kpsingh_52@yahoo.com [Academy of Scientific and Innovative Research, Council of Scientific and Industrial Research, New Delhi (India); Environmental Chemistry Division, CSIR-Indian Institute of Toxicology Research, Post Box 80, Mahatma Gandhi Marg, Lucknow 226 001 (India); Gupta, Shikha; Rai, Premanjali [Academy of Scientific and Innovative Research, Council of Scientific and Industrial Research, New Delhi (India); Environmental Chemistry Division, CSIR-Indian Institute of Toxicology Research, Post Box 80, Mahatma Gandhi Marg, Lucknow 226 001 (India)

    2013-10-15

    Robust global models capable of discriminating positive and non-positive carcinogens; and predicting carcinogenic potency of chemicals in rodents were developed. The dataset of 834 structurally diverse chemicals extracted from Carcinogenic Potency Database (CPDB) was used which contained 466 positive and 368 non-positive carcinogens. Twelve non-quantum mechanical molecular descriptors were derived. Structural diversity of the chemicals and nonlinearity in the data were evaluated using Tanimoto similarity index and Brock–Dechert–Scheinkman statistics. Probabilistic neural network (PNN) and generalized regression neural network (GRNN) models were constructed for classification and function optimization problems using the carcinogenicity end point in rat. Validation of the models was performed using the internal and external procedures employing a wide series of statistical checks. PNN constructed using five descriptors rendered classification accuracy of 92.09% in complete rat data. The PNN model rendered classification accuracies of 91.77%, 80.70% and 92.08% in mouse, hamster and pesticide data, respectively. The GRNN constructed with nine descriptors yielded correlation coefficient of 0.896 between the measured and predicted carcinogenic potency with mean squared error (MSE) of 0.44 in complete rat data. The rat carcinogenicity model (GRNN) applied to the mouse and hamster data yielded correlation coefficient and MSE of 0.758, 0.71 and 0.760, 0.46, respectively. The results suggest for wide applicability of the inter-species models in predicting carcinogenic potency of chemicals. Both the PNN and GRNN (inter-species) models constructed here can be useful tools in predicting the carcinogenicity of new chemicals for regulatory purposes. - Graphical abstract: Figure (a) shows classification accuracies (positive and non-positive carcinogens) in rat, mouse, hamster, and pesticide data yielded by optimal PNN model. Figure (b) shows generalization and predictive

  17. Uvs Nuur, Mongolia

    Science.gov (United States)

    2007-01-01

    The Uvs Nuur Basin in Mongolia and the Russian Federation is the northernmost of the enclosed basins of Central Asia. It takes its name from Uvs Nuur Lake, a large, shallow and very saline lake, very important for migrating birds. Inscribed as a UNESCO World Heritage Site in 2003, the site is made up of twelve protected areas representing major biomes of eastern Eurasia. The steppe ecosystem supports a rich diversity of birds and the desert is home to a number of rare gerbil, jerboas and the marbled polecat. The mountains are an important refuge for the endangered snow leopard, mountain sheep, and the Asiatic ibex. The image covers an area of 46 x 47.8 km, was acquired on September 4, 2001, and is located near 50.3 degrees north latitude, 90.7 degrees east longitude. The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  18. Superluminality and UV Completion

    CERN Document Server

    Shore, G M

    2007-01-01

    The idea that the existence of a consistent UV completion satisfying the fundamental axioms of local quantum field theory or string theory may impose positivity constraints on the couplings of the leading irrelevant operators in a low-energy effective field theory is critically discussed. Violation of these constraints implies superluminal propagation, in the sense that the low-frequency limit of the phase velocity $v_{\\rm ph}(0)$ exceeds $c$. It is explained why causality is related not to $v_{\\rm ph}(0)$ but to the high-frequency limit $v_{\\rm ph}(\\infty)$ and how these are related by the Kramers-Kronig dispersion relation, depending on the sign of the imaginary part of the refractive index $\\Ima n(\\w)$ which is normally assumed positive. Superluminal propagation and its relation to UV completion is investigated in detail in three theories: QED in a background electromagnetic field, where the full dispersion relation for $n(\\w)$ is evaluated numerically for the first time and the role of the null energy con...

  19. Agent, autonomous

    OpenAIRE

    Luciani, Annie

    2007-01-01

    The expression autonomous agents, widely used in virtual reality, computer graphics, artificial intelligence and artificial life, corresponds to the simulation of autonomous creatures, virtual (i.e. totally computed by a program), or embodied in a physical envelope, as done in autonomous robots.

  20. Molecular basis of carcinogenicity of tungsten alloy particles

    International Nuclear Information System (INIS)

    The tungsten alloy of 91% tungsten, 6% nickel and 3% cobalt (WNC 91–6–3) induces rhabdomyosarcoma when implanted into a rat thigh muscle. To investigate whether this effect is species-specific human HSkMc primary muscle cells were exposed to WNC 91–6–3 particles and responses were compared with those from a rat skeletal muscle cell line (L6-C11). Toxicity was assessed by the adenylate kinase assay and microscopy, DNA damage by the Comet assay. Caspase 3 enzyme activity was measured and oligonucleotide microarrays were used for transcriptional profiling. WNC 91–6–3 particles caused toxicity in cells adjacent to the particles and also increased DNA strand breaks. Inhibition of caspase 3 by WNC 91–6–3 occurred in rat but not in human cells. In both rat and human cells, the transcriptional response to WNC 91–6–3 showed repression of transcripts encoding muscle-specific proteins with induction of glycolysis, hypoxia, stress responses and transcripts associated with DNA damage and cell death. In human cells, genes encoding metallothioneins were also induced, together with genes related to angiogenesis, dysregulation of apoptosis and proliferation consistent with pre-neoplastic changes. An alloy containing iron, WNF 97–2–1, which is non-carcinogenic in vivo in rats, did not show these transcriptional changes in vitro in either species while the corresponding cobalt-containing alloy, WNC 97–2–1 elicited similar responses to WNC 91–6–3. Tungsten alloys containing both nickel and cobalt therefore have the potential to be carcinogenic in man and in vitro assays coupled with transcriptomics can be used to identify alloys, which may lead to tumour formation, by dysregulation of biochemical processes. - Highlights: • Use of transcriptomics to identify likely carcinogenic tungsten alloys in vitro • Cobalt containing alloys cause oxidative stress, DNA-damage and perturb apoptosis. • Presence of cobalt causes changes in gene expression

  1. Molecular basis of carcinogenicity of tungsten alloy particles

    Energy Technology Data Exchange (ETDEWEB)

    Harris, Robert M.; Williams, Tim D.; Waring, Rosemary H.; Hodges, Nikolas J., E-mail: n.hodges@bham.ac.uk

    2015-03-15

    The tungsten alloy of 91% tungsten, 6% nickel and 3% cobalt (WNC 91–6–3) induces rhabdomyosarcoma when implanted into a rat thigh muscle. To investigate whether this effect is species-specific human HSkMc primary muscle cells were exposed to WNC 91–6–3 particles and responses were compared with those from a rat skeletal muscle cell line (L6-C11). Toxicity was assessed by the adenylate kinase assay and microscopy, DNA damage by the Comet assay. Caspase 3 enzyme activity was measured and oligonucleotide microarrays were used for transcriptional profiling. WNC 91–6–3 particles caused toxicity in cells adjacent to the particles and also increased DNA strand breaks. Inhibition of caspase 3 by WNC 91–6–3 occurred in rat but not in human cells. In both rat and human cells, the transcriptional response to WNC 91–6–3 showed repression of transcripts encoding muscle-specific proteins with induction of glycolysis, hypoxia, stress responses and transcripts associated with DNA damage and cell death. In human cells, genes encoding metallothioneins were also induced, together with genes related to angiogenesis, dysregulation of apoptosis and proliferation consistent with pre-neoplastic changes. An alloy containing iron, WNF 97–2–1, which is non-carcinogenic in vivo in rats, did not show these transcriptional changes in vitro in either species while the corresponding cobalt-containing alloy, WNC 97–2–1 elicited similar responses to WNC 91–6–3. Tungsten alloys containing both nickel and cobalt therefore have the potential to be carcinogenic in man and in vitro assays coupled with transcriptomics can be used to identify alloys, which may lead to tumour formation, by dysregulation of biochemical processes. - Highlights: • Use of transcriptomics to identify likely carcinogenic tungsten alloys in vitro • Cobalt containing alloys cause oxidative stress, DNA-damage and perturb apoptosis. • Presence of cobalt causes changes in gene expression

  2. Effect of long-wave UV radiation on mouse melanoma: an in vitro and in vivo study

    OpenAIRE

    Pastila, Riikka

    2006-01-01

    The skin cancer incidence has increased substantially over the past decades and the role of ultraviolet (UV) radiation in the etiology of skin cancer is well established. Ultraviolet B radiation (280-320 nm) is commonly considered as the more harmful part of the UV-spectrum due to its DNA-damaging potential and well-known carcinogenic effects. Ultraviolet A radiation (320-400 nm) is still regarded as a relatively low health hazard. However, UVA radiation is the predominant component in sunlig...

  3. Biochemical and molecular aspects of mammalian susceptibility to aflatoxin B{sub 1} carcinogenicity

    Energy Technology Data Exchange (ETDEWEB)

    Massey, T.E.; Stewart, R.K. [Queen`s Univ., Kingston, Ontario (Canada); Daniels, J.M. [Environmental Health Centre, Ottawa, Ontario (Canada)] [and others

    1995-03-01

    Aflatoxin B{sub 1} (AFB{sub 1}) is a fungal toxin that has been implicated as a causative agent in human hepatic and extrahepatic carcinogenesis. In this review, the mechanisms involved in AFB{sub 1} toxicity are delineated, in order to describe the features that make a specific cell, tissue, or species susceptible to the mycotoxin. Important considerations include: (i) different mechanisms for bioactivation of AFB{sub 1} to its ultimate carcinogenic epoxide metabolite; (ii) the balance between bioactivation to and detoxification of the epoxide; (iii) the interaction of AFB{sub 1} epoxide with DNA and the mutational events leading to neoplastic transformation; (iv) the role of cytotoxicity in AFB{sub 1} carcinogenesis; (v) the significance of nonepoxide metabolites in toxicity; and (vi) the contribution of mycotoxin-unrelated disease processes. Although considerable controversy remains about the importance of specific events, a great deal has been learned about biochemical and molecular actions of AFB{sub 1}. 157 refs., 4 figs., 1 tab.

  4. Anti-carcinogenic and Anti-bacterial Properties of Selected Spices: Implications in Oral Health.

    Science.gov (United States)

    Ganjre, Anjali; Kathariya, Rahul; Bagul, Neeta; Pawar, Vivek

    2015-10-01

    "Let food be thy medicine and medicine be thy food", as said by the father of medicine, Hippocrates in 431 B.C. Nature has provided us with a variety of treatment modalities in the form of food. For the first 5,000 years of civilization, humans relied on herbs and foods for medicine. Only in the past 60 years have we forgotten our medicinal "roots" in favor of patented medicines. While pharmaceutical ingredients have their value, we should not overlook the well-documented, non-toxic and inexpensive healing properties of food. As an individual we consume food several times a day without a complete understanding of its innate qualities. As part of a daily diet, food plays a significant role in helping our bodies function at their best. There are hundreds of extremely nutritious foods, but the items in this article do more than providing healthy nutrients. Many of them consist of ingredients with hidden pharmaceutical qualities ranging from anti-inflammatory to anti-carcinogenic agent. They not only boost our innate immunity but also act as an adjunct to medicines for specific treatment. Prevention and management of symptoms can often be improved significantly through the foods we consume regularly. This paper overviews these beneficial traits of food ingredients, consumed on a daily basis, in various oral diseases. PMID:26566515

  5. N-nitrosodiethanolamine: analysis, formation in tobacco products and carcinogenicity in Syrian golden hamsters

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann, D.; Brunnemann, K.D.; Rivenson, A.; Hecht, S.S.

    1982-01-01

    An analytical GC-TEA method has been developed for the quantitative determination of N-nitrosodiethanolamine (NDELA) in tobacco and tobacco smoke. US smoking and chewing tobaccos and experimental cigarette tobaccos contained between 80 and 420 micrograms/kg of NDELA. Two snuff samples contained 3200 and 6800 micrograms/kg of NDELA. NDELA in mainstream smoke of US cigarettes amounted to 10 - 68 ng per cigarette. Evidence was presented which incriminates diethanolamine as a major precursor for NDELA in tobacco and tobacco smoke. Diethanolamine is used as a solubilizing agent for maleic hydrazide, the major sucker-growth inhibitor for US tobacco crops. NDELA was bioassayed in Syrian golden hamsters by skin painting, swabbing of the oral cavity and by subcutaneous injection. Independently of the form of application, NDELA at the higher dose (500 mg/kg) induced carcinomas of the nasal cavity, papillomas of the trachea and tumours of the larynx in some animals. NDELA uptake through the oral cavity in hamsters is presumably greater than through the skin, judging by the higher tumour yield induced by painting of the oral cavity, compared to skin painting. Studies with 14C-labeled NDELA are currently underway to document this observation quantitiatively. The present analytical data for NDELA in tobacco and tobacco smoke, together with the carcinogenicity data reported here and elsewhere, strongly suggest a review of the use of maleic hydrazide-diethanolamine as sucker-growth inhibitor in the cultivation of tobacco and other crops.

  6. Carcinogenicity, allergenicity, and lupus-inducibility of arylamines.

    Science.gov (United States)

    Chung, King-Thom

    2016-01-01

    Arylamines are widely used in food, drugs, and cosmetics as well as other industries. These chemicals are present ubiquitously in cigarette smoke, smoke emitted from cooking fume hoods as well as are generated by diverse industries. Arylamines can be generated by cleavage of azo dyes by intestinal and skin microbiota. Some arylamines are used as drugs while others are constituents of human metabolism. Many of the arylamines are mutagenic and carcinogenic. They are generally recognized as the major cause of human bladder cancer, but arylamines can induce cancers of other organs in humans and animals. Some arylamines are allergenic, causing lupus like syndrome, or other maladies. In view of their unbiquitious nature and the diseases they cause, arylamines are probably the most important chemicals causing health problems.

  7. Retraction: Evaluation of carcinogenic effects of electromagnetic fields (EMF).

    Science.gov (United States)

    Mehic, Bakir

    2010-11-01

    The Editor-in-chief of the Bosnian Journal of Basic Medical Sciences has decided to retract the article from Bayazit V et al. [1] entitled as: "Evaluation of carcinogenic effects of electromagnetic fields (EMF)" published in Bosn J Basic Med Sci. 2010 Aug;10(3):245-50. After the editorial office was alerted of possible plagiarism in the article, it conducted thorough investigation and concluded that the article apparently represents plagiarized material from two World Health Organization reports, one European Commission report and other sources. Since this is considered scientific plagiarism and scientific misconduct, Editor-in-chief has decided to withdraw the article. The authors have agreed with the editorial office decision.

  8. [Thoughts on carcinogenic pollution caused by ionizing radiation].

    Science.gov (United States)

    Latarjet, R

    1976-01-01

    The pollution phenomenon groups the effects of small doses of radiation on large populations. These effects on Man are not directly accessible. One must: a) consider some epidemiological statistics (cosmic radiation at high altitudes; radioactivity from granitic surroundings); b) extrapolate from datas obtained with high doses; c) extrapolate from datas obtained with low doses in micro-organisms or mammalian cells in vitro. The interpolation scheme of Abrahamson et al. is so available for mutagenicity. The question of a threshold remains theoretical, although radiation-induced carcinogenesis often displays a dose-effects curve with a well market threshold. A new concept, that of a "practical threshold" is developped, which may be of great usefulness. The main genetic considerations are listed upon which the present international admissible doses are based. Finally, in order to establish quantitative comparisons between chemical and radiation carcinogenic pollution, the concept of "rad equivalents" for the main chemical mutagens is stressed.

  9. A carcinogenicity study of sucralose in the CD-1 mouse.

    Science.gov (United States)

    Mann, S W; Yuschak, M M; Amyes, S J; Aughton, P; Finn, J P

    2000-01-01

    The potential carcinogenicity of sucralose was evaluated by feeding groups of 52 male and 52 female CD-1 mice a diet containing sucralose at 0.3% (3000 ppm), 1.0% (10,000 ppm) or 3.0% (30,000 ppm) for 104 weeks. A group of 72 male and 72 female mice received diet without sucralose and served as controls. Week 1 achieved doses ranging from 543 to 5870mg/kg body weight/day in the low-dose males and high-dose females, respectively. Sucralose had no adverse effect on survival. No significant changes attributable to sucralose were found in the clinical condition or behaviour of the mice. Organ weights and the gross appearance of tissues were unaffected by treatment. The mean erythrocyte counts of females receiving the highest dietary concentration were slightly, but statistically significantly, lower than those of the controls after 104 weeks of treatment. Group mean body weight gain at the highest dietary concentration of sucralose was significantly less than that of the control in mice of both sexes. Food consumption, after correction for sucralose content, was lower for female mice, but not statistically significant. Water consumption for male mice receiving the highest dietary concentration was approximately 9% higher than that of the controls. There were statistically significant increases in the incidence of several non-neoplastic findings, but these were not considered to be related to sucralose administration. Treatment with sucralose did not increase the incidence of any tumour or influence the types of tumours observed. It was concluded that sucralose is not carcinogenic in CD-1 mice. The body weight gain and erythrocyte observations at the 3.0% dietary level were of limited biological significance as they were not accompanied by any histopathologic finding and had no impact on survival. The remaining dose levels were judged to have no effects. PMID:10882820

  10. Climate therapy of psoriasis patients at Gran Canaria. High UV doses

    International Nuclear Information System (INIS)

    Psoriasis is a chronic inflammatory disease involving about 2-3% of the European population. Sun exposure has a positive effect on most psoriasis lesions, but ultraviolet (UV) radiation also causes a direct DNA damage in the skin cells and comprises a carcinogenic potential. UV exposure on the skin causes a local as well as a systemic immune suppressive effect, but the relation between sun exposure and these biological effects is not well known. In March 2006 a study was carried out to investigate possible therapeutic outcome mechanisms in 20 psoriasis patients receiving climate therapy at Gran Canaria. This paper presents estimates of their individual skin UV doses based on UV measurements and patients' diaries with information on time spent in the sun. On the first day of exposure the patients received on average 5.1 Standard Erythema Doses (SED) estimated to the skin. During the 15 days study they received 166 SED. There was no significant correlation between the therapeutic improvement and the UV dose. The UV doses were higher than if they had followed the prescribed exposure schedule and also higher than doses found from climate therapy studies at other locations. It seems beneficial to focus on the prescribed exposure schedules. (author)

  11. OVERVIEW OF DRINKING WATER MUTAGENICITY AND CARCINOGENICITY AND RISK FOR BLADDER CANCER

    Science.gov (United States)

    Among the 11 disinfection by-products (DBPs) in drinking water that are regulated by the U.S. EPA, (a) 2 DBPs (chloroacetic acid and chlorite) are not carcinogenic-in either of 2 species; (b) chlorite is not carcinogenic in 3 rodent assays and has never been tested for genotoxici...

  12. The carcinogenicity of dietary acrylamide intake: A comparative discussion of epidemiological and experimental animal research

    NARCIS (Netherlands)

    Hogervorst, J.G.F.; Baars, B.-J.; Schouten, L.J.; Konings, E.J.M.; Goldbohm, R.A.; Brandt, P.A. van den

    2010-01-01

    Since 2002, it is known that the probable human carcinogen acrylamide is present in commonly consumed carbohydrate-rich foods, such as French fries and potato chips. In this review, the authors discuss the body of evidence on acrylamide carcinogenicity from both epidemiological and rodent studies, i

  13. Inter-laboratory comparison of turkey in ovo carcinogenicity assessment (IOCA) of hepatocarcinogens.

    Science.gov (United States)

    Enzmann, H; Brunnemann, K; Iatropoulos, M; Shpyleva, S; Lukyanova, N; Todor, I; Moore, M; Spicher, K; Chekhun, V; Tsuda, H; Williams, G

    2013-09-01

    In three independent laboratories carcinogens (diethylnitrosamine, DEN, 4-(N-methyl-N-nitrosamino)-1-(3-pyridyl)-1-butanone, NNK) and non-carcinogens (N-nitrosoproline, nicotine) were evaluated in turkey eggs for in ovo carcinogenicity assessment (IOCA). Compounds were injected into aseptic fertilized eggs. After incubation for 24 days, foci of altered hepatocytes (FAH), some with a pseudoglandular structure and/or signs of compression of the surrounding tissue were observed in the fetal liver. All laboratories were able to distinguish unequivocally the hepatocarcinogen-exposed groups from those exposed to non-carcinogens or the vehicle controls, based on the pre-specified evaluation parameters: tumor-like lesions, pseudoglandular areas and FAH. In addition to focal changes, only the carcinogens induced hepatocellular karyomegaly. Lower doses of the carcinogens, which did not induce FAH, were sufficient to induce hepatocellular karyomegaly. After exposure to 4 mg DEN, gall bladder agenesis was observed in all fetuses. The IOCA may be a valuable tool for early investigative studies on carcinogenicity and since it does not use rodents may complement chronic rat or mouse bioassays. Test substances that are positive in both rodents and fertilized turkey eggs are most probably trans-species carcinogens with particular significance for humans. The good concordance observed among the three laboratories demonstrates that the IOCA is a reliable and robust method.

  14. The in vivo rodent test systems for assessment of carcinogenic potential

    DEFF Research Database (Denmark)

    van der Laan, Jan-Willem; Spindler, Per

    2002-01-01

    mouse models, the RasH2 and Tg.AC transgenic mouse models, and the neonatal mouse model. The "ICH Guideline S1B on Testing for Carcinogenicity of Pharmaceuticals" advocates that carcinogenicity testing of pharmaceuticals, when needed, might be carried out choosing one 2-year rodent carcinogenicity study...... (rat) plus one other study that supplements the 2-year study and providing additional information that is not readily available from the 2-year study: either (1) a short- or medium-term in vivo rodent test system or (2) a 2-year carcinogenicity study in a second rodent species (mouse). Another topic of...... end of 2001. The use of the short- and medium-term rodent test systems were not considered appropriate for the assessment of carcinogenic potential of biotechnology-derived medicinal products....

  15. Micro-total envelope system with silicon nanowire separator for safe carcinogenic chemistry.

    Science.gov (United States)

    Singh, Ajay K; Ko, Dong-Hyeon; Vishwakarma, Niraj K; Jang, Seungwook; Min, Kyoung-Ik; Kim, Dong-Pyo

    2016-01-01

    Exploration and expansion of the chemistries involving toxic or carcinogenic reagents are severely limited by the health hazards their presence poses. Here, we present a micro-total envelope system (μ-TES) and an automated total process for the generation of the carcinogenic reagent, its purification and its utilization for a desired synthesis that is totally enveloped from being exposed to the carcinogen. A unique microseparator is developed on the basis of SiNWs structure to replace the usual exposure-prone distillation in separating the generated reagent. Chloromethyl methyl ether chemistry is explored as a carcinogenic model in demonstrating the efficiency of the μ-TES that is fully automated so that feeding the ingredients for the generation is all it takes to produce the desired product. Syntheses taking days can be accomplished safely in minutes with excellent yields, which bodes well for elevating the carcinogenic chemistry to new unexplored dimensions. PMID:26916423

  16. Micro-total envelope system with silicon nanowire separator for safe carcinogenic chemistry

    Science.gov (United States)

    Singh, Ajay K.; Ko, Dong-Hyeon; Vishwakarma, Niraj K.; Jang, Seungwook; Min, Kyoung-Ik; Kim, Dong-Pyo

    2016-01-01

    Exploration and expansion of the chemistries involving toxic or carcinogenic reagents are severely limited by the health hazards their presence poses. Here, we present a micro-total envelope system (μ-TES) and an automated total process for the generation of the carcinogenic reagent, its purification and its utilization for a desired synthesis that is totally enveloped from being exposed to the carcinogen. A unique microseparator is developed on the basis of SiNWs structure to replace the usual exposure-prone distillation in separating the generated reagent. Chloromethyl methyl ether chemistry is explored as a carcinogenic model in demonstrating the efficiency of the μ-TES that is fully automated so that feeding the ingredients for the generation is all it takes to produce the desired product. Syntheses taking days can be accomplished safely in minutes with excellent yields, which bodes well for elevating the carcinogenic chemistry to new unexplored dimensions. PMID:26916423

  17. The role of nutritional lipids and antioxidants in UV-induced skin cancer.

    Science.gov (United States)

    Black, Homer S

    2015-06-01

    Two dietary tenets of the free radical theory of cancer require refinement. The first was dietary reduction of vulnerable free-radical targets, e.g., polyunsaturated lipids. The second was the addition of one or more antioxidants to the diet. Further, it was reported in 1939 that high levels of dietary fat exacerbated UV-carcinogenesis. Both lines of enquiry (dietary lipid and antioxidant effects on UV-carcinogenesis) were investigated. Both dietary lipids and antioxidants modified carcinogenic expression. Increasing levels of omega-6 polyunsaturated fatty acids (PUFA) exacerbated UV-carcinogenesis. However, omega-3 PUFA dramatically inhibited carcinogenic expression. It is probable that the action of omega-6 and-3 PUFA rests with differential metabolic intermediates, both tumor promoting and immune-modulating, that each PUFA generates through lipoxygenase and cyclooxygenase pathways. Antioxidant supplementation with butylated hydroxytoluene or beta-carotene demonstrated that each exerted its own specific antioxidant mechanism(s). When introduced into the complex milieu of the cell with its own intricate and complex antioxidant defense system, detrimental effects may ensue. These results point to oversimplification of these dietary suggestions to reduce cancer risk and the necessity to refine these dietary recommendations.

  18. The role of nutritional lipids and antioxidants in UV-induced skin cancer.

    Science.gov (United States)

    Black, Homer S

    2015-01-01

    Two dietary tenets of the free radical theory of cancer require refinement. The first was dietary reduction of vulnerable free-radical targets, e.g., polyunsaturated lipids. The second was the addition of one or more antioxidants to the diet. Further, it was reported in 1939 that high levels of dietary fat exacerbated UV-carcinogenesis. Both lines of enquiry (dietary lipid and antioxidant effects on UV-carcinogenesis) were investigated. Both dietary lipids and antioxidants modified carcinogenic expression. Increasing levels of omega-6 polyunsaturated fatty acids (PUFA) exacerbated UV-carcinogenesis. However, omega-3 PUFA dramatically inhibited carcinogenic expression. It is probable that the action of omega-6 and-3 PUFA rests with differential metabolic intermediates, both tumor promoting and immune-modulating, that each PUFA generates through lipoxygenase and cyclooxygenase pathways. Antioxidant supplementation with butylated hydroxytoluene or beta-carotene demonstrated that each exerted its own specific antioxidant mechanism(s). When introduced into the complex milieu of the cell with its own intricate and complex antioxidant defense system, detrimental effects may ensue. These results point to oversimplification of these dietary suggestions to reduce cancer risk and the necessity to refine these dietary recommendations. PMID:25961684

  19. The mechanisms of UV mutagenesis.

    Science.gov (United States)

    Ikehata, Hironobu; Ono, Tetsuya

    2011-01-01

    Ultraviolet (UV) light induces specific mutations in the cellular and skin genome such as UV-signature and triplet mutations, the mechanism of which has been thought to involve translesion DNA synthesis (TLS) over UV-induced DNA base damage. Two models have been proposed: "error-free" bypass of deaminated cytosine-containing cyclobutane pyrimidine dimers (CPDs) by DNA polymerase η, and error-prone bypass of CPDs and other UV-induced photolesions by combinations of TLS and replicative DNA polymerases--the latter model has also been known as the two-step model, in which the cooperation of two (or more) DNA polymerases as misinserters and (mis)extenders is assumed. Daylight UV induces a characteristic UV-specific mutation, a UV-signature mutation occurring preferentially at methyl-CpG sites, which is also observed frequently after exposure to either UVB or UVA, but not to UVC. The wavelengths relevant to the mutation are so consistent with the composition of daylight UV that the mutation is called solar-UV signature, highlighting the importance of this type of mutation for creatures with the cytosine-methylated genome that are exposed to the sun in the natural environment. UVA has also been suggested to induce oxidative types of mutation, which would be caused by oxidative DNA damage produced through the oxidative stress after the irradiation. Indeed, UVA produces oxidative DNA damage not only in cells but also in skin, which, however, does not seem sufficient to induce mutations in the normal skin genome. In contrast, it has been demonstrated that UVA exclusively induces the solar-UV signature mutations in vivo through CPD formation.

  20. A REVIEW: HERBS USED AS ANTICANCER AGENTS

    Directory of Open Access Journals (Sweden)

    Badri Nagarani

    2011-01-01

    Full Text Available Herbs are the plants which will have desirable odour, taste and other medical uses. Anti-cancer agents are effective in cancer treatment. Here an attempt has been made to review some herbs used for the prevention and treatment of cancer. These herbs were found for posses anticancer, cytotoxic or antioxidant activity in various pre-clinical or clinical studies. Cancer is a disease in which body cells become abnormal and divide without control. Cancer cell may invade nearby tissues and they may spread through the blood stream & lymphatic system to other parts of the body. The search for anticancer agents from the plant sources alkaloids in earnest in the 1950s such as Vincristine, Vinblastine and the isolation of cytotoxic Podophyllotoxins will reduce white blood cell count and caused bone marrow depression in rats. Roots, leaves, stem, root, bark and fruity of the plant herbs are used in the treatment of cancer. The dietary antioxidants having anti carcinogenic property are in demand. Identification and characterization of these anti-carcinogens in the diet can be used for reducing the risk of human cancer. Tea (Camellia thea an evergreen plant contains antioxidants which prevent and repair cellular damage caused by reactive free radicals. Supervitamin drinks containing a combination of Hordeum vulgare, Medicago sativa and Spirulina enhances the activity of immune cells against cancer. Mentha species containing antioxidants prevent reocurrence of cancer.

  1. Trading Agents

    CERN Document Server

    Wellman, Michael

    2011-01-01

    Automated trading in electronic markets is one of the most common and consequential applications of autonomous software agents. Design of effective trading strategies requires thorough understanding of how market mechanisms operate, and appreciation of strategic issues that commonly manifest in trading scenarios. Drawing on research in auction theory and artificial intelligence, this book presents core principles of strategic reasoning that apply to market situations. The author illustrates trading strategy choices through examples of concrete market environments, such as eBay, as well as abst

  2. [Ozone decline and UV increase].

    Science.gov (United States)

    Winkler, P; Trepte, S

    2004-02-01

    The following results have been obtained from long-term observations on the ozone layer and UV at the Meteorological Observatory Hohenpeigenberg:The seasonally varying decline of the ozone layer determines the maximum exposure to UV. Since ozone decline shows the highest rates in the spring months the UV exposure has most strongly increased in this time of the year. This is especially important because in spring the human skin is not adapted to UV exposure. Weather changes from day to day can induce rapid ozone reductions in spring about -30% which in turn is followed by an increase in UV of about 40%. Clouds, especially the transparent cirrus clouds (high clouds consisting of ice particles) have increased in frequency during spring and fall while a decrease is observed in summer. This change in cloudiness reduces the daily UV dose in spring and fall while it is enhanced in summer. With increasing height above sea level UV rises by roughly 10% per 1000 m (rule of thumb). Snow reflects the UV-radiation by up to 80% enhancing the UV-doses at relevant conditions. Strong volcano eruptions destroy ozone in the stratosphere additionally during 1-2 years after the eruption. Therafter the ozone layer recovers. In April 1993, after the eruption of Mt. Pinatubo (1991), the UV burden was still 40% higher than average. Miniholes and streamers can appear unexpected on a short-time scale and cross over Central Europe within 1-2 days, thus enhancing UV irradiation. The human skin reacts to UV exposure depending on the type of skin. The campaign "Sonne(n) mit Verstand" of the Bavarian Ministries for Environment, for Health and for Education informs about the danger of UV radiation (see www.sonne-mit-ver-stand.de). The German Weather Service informs the public on present developments of the ozone layer and relevant topics byits ozone bulletin, which is also available via internet under (www.dwd.de/deFundE/Observator/MOHp/hp2/ozon/bulletin.htm). PMID:14770335

  3. Histomorphological and histomorphometrical investigations of early bone damage following incorporation of optimal carcinogenic doses of 239-plutonium in male rats of different age

    International Nuclear Information System (INIS)

    There is early damage to bone at small carcinogenic amounts of the nuclide, including heavy defects of bone structure and bone marrow osteoporotic features of trabecular bone and only histomorphometrically detectable changes in bone metabolism. The dependence of radiation dose to skeleton and the spacial distribution of the nuclide on age and growth of the experimental animals is demonstrated and correlated to the histological findings. It is also shown that growth and metabolism parameters of bone influence the decorporation performance of the chelating agent Zn-DTPA. (orig.)

  4. The Methoxyflavonoid Isosakuranetin Suppresses UV-B-Induced Matrix Metalloproteinase-1 Expression and Collagen Degradation Relevant for Skin Photoaging

    Science.gov (United States)

    Jung, Hana; Lee, Eunjoo H.; Lee, Tae Hoon; Cho, Man-Ho

    2016-01-01

    Solar ultraviolet (UV) radiation is a main extrinsic factor for skin aging. Chronic exposure of the skin to UV radiation causes the induction of matrix metalloproteinases (MMPs), such as MMP-1, and consequently results in alterations of the extracellular matrix (ECM) and skin photoaging. Flavonoids are considered as potent anti-photoaging agents due to their UV-absorbing and antioxidant properties and inhibitory activity against UV-mediated MMP induction. To identify anti-photoaging agents, in the present study we examined the preventative effect of methoxyflavonoids, such as sakuranetin, isosakuranetin, homoeriodictyol, genkwanin, chrysoeriol and syringetin, on UV-B-induced skin photo-damage. Of the examined methoxyflavonoids, pretreatment with isosakuranetin strongly suppressed the UV-B-mediated induction of MMP-1 in human keratinocytes in a concentration-dependent manner. Isosakuranetin inhibited UV-B-induced phosphorylation of mitogen-activated protein kinase (MAPK) signaling components, ERK1/2, JNK1/2 and p38 proteins. This result suggests that the ERK1/2 kinase pathways likely contribute to the inhibitory effects of isosakuranetin on UV-induced MMP-1 production in human keratinocytes. Isosakuranetin also prevented UV-B-induced degradation of type-1 collagen in human dermal fibroblast cells. Taken together, our findings suggest that isosakuranetin has the potential for development as a protective agent for skin photoaging through the inhibition of UV-induced MMP-1 production and collagen degradation. PMID:27598131

  5. The Methoxyflavonoid Isosakuranetin Suppresses UV-B-Induced Matrix Metalloproteinase-1 Expression and Collagen Degradation Relevant for Skin Photoaging.

    Science.gov (United States)

    Jung, Hana; Lee, Eunjoo H; Lee, Tae Hoon; Cho, Man-Ho

    2016-01-01

    Solar ultraviolet (UV) radiation is a main extrinsic factor for skin aging. Chronic exposure of the skin to UV radiation causes the induction of matrix metalloproteinases (MMPs), such as MMP-1, and consequently results in alterations of the extracellular matrix (ECM) and skin photoaging. Flavonoids are considered as potent anti-photoaging agents due to their UV-absorbing and antioxidant properties and inhibitory activity against UV-mediated MMP induction. To identify anti-photoaging agents, in the present study we examined the preventative effect of methoxyflavonoids, such as sakuranetin, isosakuranetin, homoeriodictyol, genkwanin, chrysoeriol and syringetin, on UV-B-induced skin photo-damage. Of the examined methoxyflavonoids, pretreatment with isosakuranetin strongly suppressed the UV-B-mediated induction of MMP-1 in human keratinocytes in a concentration-dependent manner. Isosakuranetin inhibited UV-B-induced phosphorylation of mitogen-activated protein kinase (MAPK) signaling components, ERK1/2, JNK1/2 and p38 proteins. This result suggests that the ERK1/2 kinase pathways likely contribute to the inhibitory effects of isosakuranetin on UV-induced MMP-1 production in human keratinocytes. Isosakuranetin also prevented UV-B-induced degradation of type-1 collagen in human dermal fibroblast cells. Taken together, our findings suggest that isosakuranetin has the potential for development as a protective agent for skin photoaging through the inhibition of UV-induced MMP-1 production and collagen degradation. PMID:27598131

  6. The Methoxyflavonoid Isosakuranetin Suppresses UV-B-Induced Matrix Metalloproteinase-1 Expression and Collagen Degradation Relevant for Skin Photoaging

    Directory of Open Access Journals (Sweden)

    Hana Jung

    2016-09-01

    Full Text Available Solar ultraviolet (UV radiation is a main extrinsic factor for skin aging. Chronic exposure of the skin to UV radiation causes the induction of matrix metalloproteinases (MMPs, such as MMP-1, and consequently results in alterations of the extracellular matrix (ECM and skin photoaging. Flavonoids are considered as potent anti-photoaging agents due to their UV-absorbing and antioxidant properties and inhibitory activity against UV-mediated MMP induction. To identify anti-photoaging agents, in the present study we examined the preventative effect of methoxyflavonoids, such as sakuranetin, isosakuranetin, homoeriodictyol, genkwanin, chrysoeriol and syringetin, on UV-B-induced skin photo-damage. Of the examined methoxyflavonoids, pretreatment with isosakuranetin strongly suppressed the UV-B-mediated induction of MMP-1 in human keratinocytes in a concentration-dependent manner. Isosakuranetin inhibited UV-B-induced phosphorylation of mitogen-activated protein kinase (MAPK signaling components, ERK1/2, JNK1/2 and p38 proteins. This result suggests that the ERK1/2 kinase pathways likely contribute to the inhibitory effects of isosakuranetin on UV-induced MMP-1 production in human keratinocytes. Isosakuranetin also prevented UV-B-induced degradation of type-1 collagen in human dermal fibroblast cells. Taken together, our findings suggest that isosakuranetin has the potential for development as a protective agent for skin photoaging through the inhibition of UV-induced MMP-1 production and collagen degradation.

  7. UV survival of human mycoplasmas

    International Nuclear Information System (INIS)

    The inactivation by ultraviolet (UV) light irradiation of mycoplasma cells of five human strains was monitored by investigating the colony-forming ability. The survival curves of five strains tested indicated that the cells of Mycoplasma buccale only are single and homogenously susceptible to UV light. The effect of the repair inhibitor, caffeine, on the colony-forming ability of UV-irradiated cells was investigated with M. buccale because of its homogeneous susceptibility to UV light. The colony formation of irradiated cells was markedly depressed by post-irradiation treatment with caffeine at concentration that had little or no effect on the colony formation of unirradiated cells. The colony-forming units (CFU) of UV-irradiated cells which were kept in broth without caffeine in the dark increased without a lag as the time in the dark increased. The colony-forming ability of the irradiated cells completely recovered after 3 hr in the dark. However, when irradiated cells were kept in the presence of caffeine, no increase in their CFU was observed. The mode of action of caffeine on UV-irradiated cells closely resembles that described for other organisms which possess dark reactivation systems for UV-induced damage in deoxyribonucleic acid. Thus, the results obtained provide evidence for the existence of a dark repair function in M. buccale. (author)

  8. UV-type damage associated with ionizing radiation: a review

    International Nuclear Information System (INIS)

    The induction of UV-type damage by ionizing radiation in repair deficient strains of E. coli is reviewed. Both photoreactivable and non-photoreactivable types of damage can be observed. The induction of UV-type damage is largely independent of the presence of free-radical reactive agents (e.g. oxygen and thiols), but is dependent upon the energy of the photon-or electron-beam used, the radiation geometry and the optical absorbance of the extracellular medium. On the basis of calculations and experimental evidence, it is clear that one mechanism whereby such damage arises is through the generation of Cerenkov emission. However, small yields of UV-type damage can be produced using X-rays whose energy is below the threshold for production of Cerenkov emission. In this instance, the damage induction mechanism is thought to involve a direct excitation process. (author)

  9. Ecotoxicity of carbamazepine and its UV photolysis transformation products

    DEFF Research Database (Denmark)

    Donner, E.; Kosjek, T.; Qualmann, Signe;

    2013-01-01

    Carbamazepine, an anti-epileptic pharmaceutical agent commonly found in wastewater, is highly recalcitrant to standard wastewater treatment practices. This study investigated the mixture toxicity of carbamazepine transformation products formed during ultraviolet (UV) photolysis using three standard...... considerably more toxic than carbamazepine itself may be produced during UV-treatment of wastewater effluents and/or photo-induced degradation of carbamazepine in natural waters. This study highlights the need to consider mixture toxicity and the formation and persistence of toxicologically relevant...... ecotoxicity assays (representing bacteria, algae and crustaceans). UV-treatment of 6 mg L− 1 carbamazepine solution was carried out over a 120 min period and samples were removed periodically over the course of the experiment. Quantification results confirmed the degradation of carbamazepine throughout...

  10. Tobacco carcinogen induces both lung cancer and non-alcoholic steatohepatitis and hepatocellular carcinomas in ferrets which can be attenuated by lycopene supplementation.

    Science.gov (United States)

    Aizawa, Koichi; Liu, Chun; Tang, Sanyuan; Veeramachaneni, Sudipta; Hu, Kang-Quan; Smith, Donald E; Wang, Xiang-Dong

    2016-09-01

    Early epidemiologic studies have reported that tobacco smoking, which is causally associated with liver cancer, is an independent risk factor for non-alcoholic fatty liver diseases (NAFLD). Lycopene from tomatoes has been shown to be a potential preventive agent against NAFLD and hepatocellular carcinoma (HCC). In the present study, we investigated whether the tobacco carcinogen 4-(N-methyl-N-nitrosamino)-1-(3-pyridyl)-1-butanone (NNK) induces lesions in both lungs and livers of ferrets with or without lycopene intervention. Male ferrets (6 groups, n = 8-10) were treated either with NNK (50 mg/kg BW, i.p., once a month for four consecutive months) or saline with or without dietary lycopene supplementation (2.2 and 6.6 mg/kg BW/day, respectively) for 26 weeks. Results demonstrate that NNK exposure results in higher incidences of lung tumors, HCC and steatohepatitis (which is characterized by severe inflammatory cell infiltration with concurrent fat accumulation in liver, hepatocellular ballooning degeneration and increased NF-κB expression), as well as elevations in bilirubin and AST levels in ferrets. Lycopene supplementation at two doses prevented NNK-induced expressions of α7 nicotinic acetylcholine receptor in the lung and NF-κB and CYP2E1 in the liver and attenuated the NNK-induced mortality and pathological lesions in both the lungs and livers of ferrets. The present study provided strong experimental evidence that the tobacco carcinogen NNK can induce both HCC and steatohepatitis in the ferrets and can be a useful model for studying tobacco carcinogen-associated NAFLD and liver cancer. Furthermore, lycopene could provide potential benefits against smoke carcinogen-induced pulmonary and hepatic injury. PMID:27116542

  11. Human carcinogens: an evaluation study via the COMPACT and HazardExpert procedures.

    Science.gov (United States)

    Lewi, D F V; Bird, M G; Jacobs, M N

    2002-03-01

    The results of computer-optimized molecular parametric analysis of chemical toxicity (COMPACT) and HazardExpert evaluations on 14 established human carcinogens are reported. The concordances between COMPACT and carcinogenicity (71%) and between HazardExpert and carcinogenicity (57%) are significantly improved when taken in combination, where all 14 carcinogens are correctly identified by the two systems used in conjunction. However, if a negative energy of the highest occupied molecular orbital (E(HOMO)) value is regarded as evidence of electrophilic reactivity likely to give rise to mutagenicity and carcinogenicity, then 13/14 (93%) of the carcinogens are correctly identified by combination with the COMPACT procedure alone. It is possible, therefore, to establish likely carcinogenicity arising from either P450 mediation (CYP1 and CYP2E) or compound electrophilicity via the employment of a straightforward approach to molecular and electronic structure calculation, a process that can be performed in a relatively short time frame (i.e., less than 1 hour per chemical) and at a low cost. PMID:12102536

  12. The carcinogenic effects of aspartame: The urgent need for regulatory re-evaluation.

    Science.gov (United States)

    Soffritti, Morando; Padovani, Michela; Tibaldi, Eva; Falcioni, Laura; Manservisi, Fabiana; Belpoggi, Fiorella

    2014-04-01

    Aspartame (APM) is an artificial sweetener used since the 1980s, now present in >6,000 products, including over 500 pharmaceuticals. Since its discovery in 1965, and its first approval by the US Food and Drugs Administration (FDA) in 1981, the safety of APM, and in particular its carcinogenicity potential, has been controversial. The present commentary reviews the adequacy of the design and conduct of carcinogenicity bioassays on rodents submitted by G.D. Searle, in the 1970s, to the FDA for market approval. We also review how experimental and epidemiological data on the carcinogenic risks of APM, that became available in 2005 motivated the European Commission (EC) to call the European Food and Safety Authority (EFSA) for urgent re-examination of the available scientific documentation (including the Searle studies). The EC has further requested that, if the results of the evaluation should suggest carcinogenicity, major changes must be made to the current APM specific regulations. Taken together, the studies performed by G.D. Searle in the 1970s and other chronic bioassays do not provide adequate scientific support for APM safety. In contrast, recent results of life-span carcinogenicity bioassays on rats and mice published in peer-reviewed journals, and a prospective epidemiological study, provide consistent evidence of APM's carcinogenic potential. On the basis of the evidence of the potential carcinogenic effects of APM herein reported, a re-evaluation of the current position of international regulatory agencies must be considered an urgent matter of public health.

  13. Sun, UV Radiation and Your Eyes

    Science.gov (United States)

    ... Eye Health / Tips & Prevention Your Eyes and the Sun Sections The Sun, UV Radiation and Your Eyes ... Best Sunglasses Sun Smart UV Safety Infographic The Sun, UV Radiation and Your Eyes Written by: David ...

  14. Urban air carcinogens and their effects on health

    Energy Technology Data Exchange (ETDEWEB)

    Lechner, J.F.

    1994-11-01

    Airborne carcinogens may be relevant especially in metropolitan regions with extreme smog as a primary cause of lung cancer. Lung cancer is most common in urban environs and the incidence directly correlates with the size of the city. In addition, several, but not all formal epidemiological studies also suggest a positive correlation between lung cancer incidence and the intensity of air pollution exposure. There is further support for a role of air pollution; as of 1993, 4.4% of all of the bronchogenic adenocarcinoma cancer cases among Mexicans living in industrialized cities are under 40 years of age. It is plausible that chronic inhalation of automobile combustion products, factory emissions, and/or radon is at least partially responsible for the higher incidence of lung cancer exemplified by the never-smoking urban residents. The exceptionally high incidence of lung cancer cases among never-smokers living in highly industrialized Mexican cities offers a unique opportunity to use molecular epidemiology to test whether chronic inhalation of atmospheric pollutants increases the risk for this disease. Overall, the analysis of the genetic alterations in two cancer genes, and possibly the hprt locus should give new insight as to whether the urban never-smokers developed their cancers because of exposure to environmental pollutants.

  15. [Urban air pollution by carcinogenic N-nitrosamines].

    Science.gov (United States)

    Khesina, A Ia; Krivosheeva, L V; Sokol'skaia, N N; Koliadich, M N

    1996-01-01

    Moscow is used as an example to discuss the problem of urban atmospheric pollution by carcinogenic N-nitrosamines. An analytical method is proposed, which is based on the use of a Russian gas chromatograph compatible with a chemiluminescence detector, that is a TEA thermal energy analyzer (USA) having some modifications to reduce the time of analysis and loss during sample pretreatment. The minimal detected concentration is 3 ng/m3 for 2-hour sampling. The method identifies and quantifies 7 volatile N-nitrosamines: N-nitrosodimethylamine (NDMA), N-nitrosodiethylamine, N-nitrosodibutylamine, N-nitrosodipropylamine, N-nitrosopiperidine, N-nitrosopyrrolidine, N-nitrosomorpholine. The pollution of the Moscow air was evaluated in the center of Moscow (30-60 ng/m3 for NDMA), in the industrial emission area (as high as several hundred ng/m3, and in the heavy traffic area (100 ng/m3 or more). It is proposed to study the working area for rubber and tire industries, to establish nitrosamine tolerances for these industries and maximum allowable discharge concentrations in the urban air and to monitor these parameters. PMID:8672956

  16. Radioprotective Agents

    Directory of Open Access Journals (Sweden)

    Ilker Kelle

    2008-01-01

    Full Text Available Since1949, a great deal of research has been carried out on the radioprotective activity of various chemical substances. Thiol compounds, compounds which contain –SH radical, different classes of pharmacological agents and other compounds such as vitamine C and WR-2721 have been shown to reduce mortality when administered prior to exposure to a lethal dose of radiation. Recently, honey bee venom as well as that of its components melittin and histamine have shown to be valuable in reduction of radiation-induced damage and also provide prophylactic alternative treatment for serious side effects related with radiotherapy. It has been suggested that the radioprotective activity of bee venom components is related with the stimulation of the hematopoetic system.

  17. Classification of weakly carcinogenic human papillomavirus types: addressing the limits of epidemiology at the borderline

    Directory of Open Access Journals (Sweden)

    Buonaguro Franco M

    2009-06-01

    Full Text Available Abstract Virtually all cases of cervical cancer are caused by persistent infections with a restricted set of human papillomaviruses (HPV. Some HPV types, like HPV16 and HPV18, are clear and powerful carcinogens. However, the categorization of the most weakly carcinogenic HPV types is extremely challenging. The decisions are important for screening test and vaccine development. This article describes for open discussion an approach recently taken by a World Health Organization International Agency for Research on Cancer (IARC Monographs Working Group to re-assess the carcinogenicity of different HPV types.

  18. Mechanism of UV photoreactivity of alkylsiloxane self-assembled monolayers.

    Science.gov (United States)

    Ye, Tao; McArthur, Eric A; Borguet, Eric

    2005-05-26

    A molecular level understanding of the photoreactivity of self-assembled monolayers (SAMs) becomes increasingly important as the spatial resolution starts to be limited by the size of the resist and the spatial extent of the photochemical reactions in photoresist micropatterning. To this end, a number of surface characterization techniques were combined to understand the reactive agents, reactive sites, kinetics, and reaction pathways in the UV photoreactivity of octadecylsiloxane (ODS) SAMs. Quantitative analysis of our results provides evidence that ground state atomic oxygen is the primary reactive agent for the UV degradation of ODS SAMs. UV degradation, which follows zero-order kinetics, results in the scission of alkyl chains instead of the siloxane headgroups. Our results suggest that the top of the ODS SAMs is the preferential reactive site. Using a novel, highly surface sensitive technique, fluorescence labeling of surface species, we identified the presence of submonolayer quantities chemical functional groups formed by the UV degradation. These groups are intermediates in a proposed mechanism based on hydrogen abstraction. PMID:16852200

  19. Low gloss UV-cured coatings for aircraft

    Energy Technology Data Exchange (ETDEWEB)

    Bowman, Mark; Muschar, Harry

    2014-12-09

    A method of applying a low gloss coating to a substrate such as the exterior surface of an aircraft is disclosed. The coating composition comprising a polyene, a polythiol, a flatting agent and a coloring pigment is applied to the substrate and given a first dosage of UV radiation followed by a second dosage in which the second dosage is greater than the first resulting in an ultralow gloss coating.

  20. An agent framework for dynamic agent retraining: Agent academy

    OpenAIRE

    Mitkas, P.; A. Symeonidis; Kechagias, D.; Athanasiadis, I.N.; Laleci, G.; KURT, G.; Kabak, Y.; Acar, A.; Dogac, A.

    2004-01-01

    Agent Academy (AA) aims to develop a multi-agent society that can train new agents for specific or general tasks, while constantly retraining existing agents in a recursive mode. The system is based on collecting information both from the environment and the behaviors of the acting agents and their related successes/failures to generate a body of data, stored in the Agent Use Repository, which is mined by the Data Miner module, in order to generate useful knowledge about the application domai...

  1. Regulation of immune suppression induced by UV radiation

    International Nuclear Information System (INIS)

    Full text: Exposure of the skin of mice and men to increasing doses of UV radiation causes erythema, blistering, accelerated photoageing, DNA lesions and photocarcinogenesis. Moderate exposure also suppresses T cell-mediated immune function, a defect which is a prerequisite for the promotion or outgrowth phase of the UV-initiated tumour, and which is accompanied by dysregulated cutaneous cytokine patterns. A major cutaneous photoreceptor for the immunosuppression is epidermal urocanic acid (UCA). Naturally occurring trans-UCA photoisomerises in the stratum corneum and epidermis to cis-UCA, in a direct reaction. Cis-UCA has been found to have local and systemic immunosuppressive properties. The action spectrum for the photoimmuno-suppression is maximal in the UVB (280 320nm) waveband. However longer wavelength UVA (320-400nm), which interacts with skin predominantly via oxidative reactions, is not immunosuppressive at environmental exposure doses, and unexpectedly can provide protection from UVB-immunosuppression. We find that UVA protective exposure prevents the major UVB-alterations to the cytokine array. In addition, UVA (but not UVB) exposure induces cutaneous haem oxygenase (HO) activity, an endogenous antioxidant enzyme. HO is known to be redox-regulated, and to be the major stress protein induced in cultured fibroblasts by UVA. We find that UVA-immune protection is dependent on the induced HO; that enhanced HO activity following UVA is cytokine-dependent; and that the induced HO acts by inhibiting the immunosuppressive potential of cis-UCA. Thus oxidant states resulting predominantly from UVA irradiation, while apparently immunologically innocuous, seem to actively upregulate this defensive HO response. These studies have therefore revealed interactions between different UV wavebands important for immune regulation both in the skin and systemically, which may have a critical bearing on the carcinogenic outcome in chronically exposed skin, and offer the

  2. Biomarkers for assessing potential carcinogenic effects of chronic arsenic exposure in Inner Mongolia, CHINA

    Science.gov (United States)

    Arsenic is ubiquitous in the environment. Chronic arsenic exposure via drinking water has been associated. with carcinogenic, cardiovascular, neurological and diabetic effects in humans and has been of great public health concern worldwide. In 2001, U.S. Environmental Protection ...

  3. AI AND SAR APPROACHES FOR PREDICTING CHEMICAL CARCINOGENICITY: SURVEY AND STATUS REPORT

    Science.gov (United States)

    A wide variety of artificial intelligence (AI) and structure-activity relationship (SAR approaches have been applied to tackling the general problem of predicting rodent chemical carcinogenicity. Given the diversity of chemical structures and mechanisms relative to this endpoin...

  4. 29 CFR 1990.131 - Priority lists for regulating potential occupational carcinogens.

    Science.gov (United States)

    2010-07-01

    ... List. The inclusion or exclusion of any substance on these lists shall not be subject to judicial... carcinogen which has not been placed on these lists. The inclusion of a substance on either of these...

  5. Carcinogenicity evaluation for the application of carbon nanotubes as biomaterials in rasH2 mice

    Science.gov (United States)

    Takanashi, Seiji; Hara, Kazuo; Aoki, Kaoru; Usui, Yuki; Shimizu, Masayuki; Haniu, Hisao; Ogihara, Nobuhide; Ishigaki, Norio; Nakamura, Koichi; Okamoto, Masanori; Kobayashi, Shinsuke; Kato, Hiroyuki; Sano, Kenji; Nishimura, Naoyuki; Tsutsumi, Hideki; Machida, Kazuhiko; Saito, Naoto

    2012-07-01

    The application of carbon nanotubes (CNTs) as biomaterials is of wide interest, and studies examining their application in medicine have had considerable significance. Biological safety is the most important factor when considering the clinical application of CNTs as biomaterials, and various toxicity evaluations are required. Among these evaluations, carcinogenicity should be examined with the highest priority; however, no report using transgenic mice to evaluate the carcinogenicity of CNTs has been published to date. Here, we performed a carcinogenicity test by implanting multi-walled CNTs (MWCNTs) into the subcutaneous tissue of rasH2 mice, using the carbon black present in black tattoo ink as a reference material for safety. The rasH2 mice did not develop neoplasms after being injected with MWCNTs; instead, MWCNTs showed lower carcinogenicity than carbon black. Such evaluations should facilitate the clinical application and development of CNTs for use in important medical fields.

  6. Determination of potentially carcinogenic compounds in food : trace analysis of vinylchloride, vinylidenechloride, acrylonitrile, epichlorohydrin and diethylpyrocarbonate

    NARCIS (Netherlands)

    Lierop, van J.B.H.

    1979-01-01

    Toxicological evidence shows that some monomers present in packaging materials may be carcinogenic. These monomers, notably vinylchloride, vinylidenechloride, acrylonitrile and epichlorohydrin, may migrate from the packaging material into the food. Therefore, severe limits are set to the contents of

  7. 78 FR 15020 - Report on Carcinogens Webinar on Pentachlorophenol; Notice of Public Webinar and Registration...

    Science.gov (United States)

    2013-03-08

    ... HUMAN SERVICES National Institutes of Health Report on Carcinogens Webinar on Pentachlorophenol; Notice of Public Webinar and Registration Information SUMMARY: The National Toxicology Program (NTP) announces a public webinar, ``Human cancer studies on exposure to pentachlorophenol (PCP):...

  8. Correlation of levels of volatile versus carcinogenic particulate polycyclic aromatic hydrocarbons in air samples from smokehouses

    DEFF Research Database (Denmark)

    Hansen, Åse Marie; Poulsen, O M; Christensen, J M

    1991-01-01

    In the present study, data on the concentration of polycyclic aromatic hydrocarbons (PAH) in air samples from fish smokehouses (Nordholm et al. 1986) and meat smokehouses (Hansen et al. submitted for publication) were used to analyze the extent to which six different volatile PAH compounds could...... carcinogenic PAH compounds in air samples from smokehouses, whereas fluoranthene and pyrene displayed the highest specificity. However, when the applicability of the six markers was tested on air samples from iron foundries, only naphthalene and pyrene were useful as markers for the carcinogenic compounds...... function as markers for the total concentration of six different carcinogenic particulate PAH compounds. Although a significant positive correlation was observed between the concentration of each of six volatile compounds and the total concentration of carcinogenic PAH compounds, a particularly good...

  9. 78 FR 57868 - Nominations to the Report on Carcinogens; Request for Information

    Science.gov (United States)

    2013-09-20

    ... RoC. 20 Substances Nominated to the RoC* Aloe vera whole leaf extract (Aloe barbadensis Miller) 2..., ongoing, or planned studies related to evaluating carcinogenicity; (3) scientific issues important...

  10. DNA damage caused by UV- and near UV-irradiation

    International Nuclear Information System (INIS)

    Much work with mutants deficient in DNA repair has been performed concerning UV-induced DNA damage under the condition where there is no artificial stimulation. In an attempt to infer the effects of solar wavelengths, the outcome of the work is discussed in terms of cellular radiation sensitivity, unscheduled DNA synthesis, and mutation induction, leading to the conclusion that some DNA damage occurs even by irradiation of the shorter wavelength light (270 - 315 nm) and is repaired by excision repair. It has been thought to date that pyrimidine dimer (PD) plays the most important role in UV-induced DNA damage, followed by (6 - 4) photoproducts. As for DNA damage induced by near UV irradiation, the yield of DNA single-strand breaks and of DNA-protein crosslinking, other than PD, is considered. The DNA-protein crosslinking has proved to be induced by irradiation at any wavelength of UV ranging from 260 to 425 nm. Near UV irradiation causes the inhibition of cell proliferation to take place. (Namekawa, K.)

  11. Carcinogenicity of sublimed urethane in mice through the respiratory tract.

    Science.gov (United States)

    Nomura, T; Hayashi, T; Masuyama, T; Tanaka, S; Nakajima, H; Kurokawa, N; Isa, Y

    1990-08-01

    The carcinogenicity of sublimed urethane (ethyl carbamate) in air was examined with mice. JCL:ICR mice were nursed in a plastic cage inside a vinyl chamber which was ventilated 4 times per hour. The mice were exposed to urethane gas for various periods by passing air which contained a high concentration of sublimed urethane (1.29 micrograms/ml) into the vinyl chamber, or by placing a vessel containing crystalline urethane inside the vinyl chamber so that it was filled with spontaneously-sublimed urethane gas at a low concentration (0.25 microgram/ml). When female mice were killed 5 months after exposure, lung tumor frequency increased almost linearly with the number of days of exposure in the low concentration experiment, but increased in a non-linear manner in the high concentration experiment. In terms of nearly the same total dose, i.e., (concentration of urethane gas in air) X (days of inhalation), one day of exposure to urethane gas at the low concentration induced lung tumors at a significantly higher frequency than 1/4 day of exposure to urethane gas at the high concentration. When male mice were killed at 12 months after exposure to examine the progressive change of induced tumors, malignant, invasive and metastatic tumors were found to have been induced more frequently in the lung after exposure to urethane gas at the low concentration (0.25 microgram/ml for 10 days) than at the high concentration (1.29 microgram/ml for 4 days), although the total dose in the former group was about half of that in the latter. Continuous exposure to urethane gas for a longer period at the low concentration seems to be more efficient for the induction, promotion and/or progression of lung tumors than the exposure for a shorter period at the high concentration.

  12. Genotoxicity of Disinfection By-products: Comparison to Carcinogenicity

    Science.gov (United States)

    Disinfection by-products (DBPs) can be formed when water is disinfected by various agents such as chlorine, ozone, or chloramines. Among the >600 DBPs identified in drinking water, 11 are regulated by the U.S. Environmental Protection Agency, and another ~70 DBPs that occur at s...

  13. Carcinogenic effects of the combined action of /sup 241/Am and. gamma. -radiation

    Energy Technology Data Exchange (ETDEWEB)

    Filippova, L.G.; Buldakov, L.A.; Nifatov, A.P. (Institut Biofiziki, Moscow (USSR))

    In experiments on Wistar rats a study was made of the carcinogenic effects of the combined exposure to /sup 241/Am administered intrapertioneally (6.7 to 229.4 kBq/kg body weight) and external ..gamma..-radiation (/sup 137/Cs, 175 cGy). The occurrence of osteosarcoma, leucosis, skin and mammary tumors increased in the exposed animals. The combined irradiation produced an additive carcinogenic effect.

  14. Analysis of carcinogenicity testing for regulatory purposes in the European Union

    OpenAIRE

    MADIA FEDERICA; Worth, Andrew; Corvi, Raffaella

    2016-01-01

    The approaches for evaluating the carcinogenic potential of substances, including whether carcinogenicity studies should be conducted, differ substantially across sectors. Despite variations in testing schemes, the two-year bioassay study in rodents represents the standard element across all sectors. The validity of the two-year bioassay though has been questioned in the last decade. Uncertainty is associated with the extrapolation of data from rodents to humans. Furthermore, these stud...

  15. Recent developments in the multistage modeling of cohort data for carcinogenic risk assessment.

    OpenAIRE

    Mazumdar, S; Redmond, C K; Costantino, J P; Patwardhan, R N; Zhou, S. Y.

    1991-01-01

    The modeling of cohort data based on the Armitage-Doll multistage model of the carcinogenic process has gained popular acceptance as a methodology for quantitative risk assessment for estimating the dose-related relationships between different occupational and environmental carcinogenic exposures and cancer mortality. The multistage model can be used for extrapolation to low doses relevant for setting environmental standards and also provides information regarding whether more than one stage ...

  16. In vivo transgenic bioassays and assessment of the carcinogenic potential of pharmaceuticals.

    OpenAIRE

    Contrera, J F; DeGeorge, J J

    1998-01-01

    There is general agreement in the scientific community on the need to improve carcinogenicity testing and the assessment of human carcinogenic risk and to incorporate more information on mechanisms and modes of action into the risk assessment process. Advances in molecular biology have identified a growing number of genes such as protooncogenes and tumor-suppressor genes that are highly conserved across species and are associated with a wide variety of human and animal cancers. In vivo transg...

  17. Effect of DNA type on response of DNA biosensor for carcinogens

    Science.gov (United States)

    Sani, Nor Diyana bt. Md.; Heng, Lee Yook; Surif, Salmijah; Lazim, Azwani Mat

    2013-11-01

    Carcinogens are cancer causing chemicals that can bind to DNA and cause damage to the DNA. These chemicals are available everywhere including in water, air, soil and food. Therefore, a sensor that can detect the presence of these chemicals will be a very useful tool. Since carcinogens bind to DNA, DNA can be used as the biological element in a biosensor. This study has utilized different types of DNA in a biosensor for carcinogen detection. The DNAs include double stranded calf thymus DNA, single stranded calf thymus DNA and guanine rich single stranded DNA. The modified SPE was exposed to a carcinogen followed by interaction with methylene blue which acts as the electroactive indicator. The SPE was then analysed using differential pulse voltammetry (DPV). Optimization studies were conducted for MB concentration and accumulation time, DNA concentration, as well as effect of buffer concentration, buffer pH and ionic strength. The performance of the biosensor was tested on a group 1 carcinogen, formaldehyde. The results indicated that the usage of guanine rich single stranded DNA also gives higher response as carcinogens prefer to bind with guanine compared to other bases.

  18. A comprehensive review of the carcinogenic and anticarcinogenic potential of capsaicin.

    Science.gov (United States)

    Bley, Keith; Boorman, Gary; Mohammad, Bashir; McKenzie, Donald; Babbar, Sunita

    2012-08-01

    Human exposure to capsaicin, the most abundant pungent chili pepper component, is ubiquitous. Evaluation of capsaicin's carcinogenic potential has produced variable results in in vitro and in vivo genotoxicity and carcinogenicity assays. The capsaicin tested in older studies was often from pepper plant extracts and included other capsaicinoids and diverse impurities. Recent studies utilizing high-purity capsaicin and standardized protocols provide evidence that the genotoxic and carcinogenic potential of capsaicin is quite low and that the purity of capsaicin is important. Several small epidemiological studies suggest a link between capsaicin consumption and stomach or gall bladder cancer, but contamination of capsaicin-containing foods with known carcinogens renders their interpretation problematic. The postulated ability of capsaicin metabolites to damage DNA and promote carcinogenesis remains unsupported. Anticancer activities of capsaicin have been widely reported, as it inhibits the activity of carcinogens and induces apoptosis in numerous cancer cell lines in vitro and explanted into rodents. Diverse mechanisms have been postulated for capsaicin's anticancer properties. One hypothesis is that inhibition of cytochrome P450 enzymes-particularly CYP2E1-retards carcinogen activation but is contradicted by the low potency of capsaicin for CYP inhibition. The potential for dietary capsaicin to act as a chemopreventative is now widely postulated. PMID:22563012

  19. Exposure to Crystal Violet, Its Toxic, Genotoxic and Carcinogenic Effects on Environment and Its Degradation and Detoxification for Environmental Safety.

    Science.gov (United States)

    Mani, Sujata; Bharagava, Ram Naresh

    2016-01-01

    Crystal Violet (CV), a triphenylmethane dye, has been extensively used in human and veterinary medicine as a biological stain, as a textile dye in textile processing industries and also used to provide a deep violet color to paints and printing ink. CV is also used as a mutagenic and bacteriostatic agent in medical solutions and antimicrobial agent to prevent the fungal growth in poultry feed. Inspite of its many uses, CV has been reported as a recalcitrant dye molecule that persists in environment for a long period and pose toxic effects in environment. It acts as a mitotic poison, potent carcinogen and a potent clastogene promoting tumor growth in some species of fish. Thus, CV is regarded as a biohazard substance. Although, there are several physico-chemical methods such as adsorption, coagulation and ion-pair extraction reported for the removal of CV, but these methods are insufficient for the complete removal of CV from industrial wastewaters and also produce large quantity of sludge containing secondary pollutants. However, biological methods are regarded as cost-effective and eco-friendly for the treatment of industrial wastewaters, but these methods also have certain limitations. Therefore, there is an urgent need to develop such eco-friendly and cost-effective biological treatment methods, which can effectively remove the dye from industrial wastewaters for the safety of environment, as well as human and animal health. PMID:26613989

  20. Exposure to Crystal Violet, Its Toxic, Genotoxic and Carcinogenic Effects on Environment and Its Degradation and Detoxification for Environmental Safety.

    Science.gov (United States)

    Mani, Sujata; Bharagava, Ram Naresh

    2016-01-01

    Crystal Violet (CV), a triphenylmethane dye, has been extensively used in human and veterinary medicine as a biological stain, as a textile dye in textile processing industries and also used to provide a deep violet color to paints and printing ink. CV is also used as a mutagenic and bacteriostatic agent in medical solutions and antimicrobial agent to prevent the fungal growth in poultry feed. Inspite of its many uses, CV has been reported as a recalcitrant dye molecule that persists in environment for a long period and pose toxic effects in environment. It acts as a mitotic poison, potent carcinogen and a potent clastogene promoting tumor growth in some species of fish. Thus, CV is regarded as a biohazard substance. Although, there are several physico-chemical methods such as adsorption, coagulation and ion-pair extraction reported for the removal of CV, but these methods are insufficient for the complete removal of CV from industrial wastewaters and also produce large quantity of sludge containing secondary pollutants. However, biological methods are regarded as cost-effective and eco-friendly for the treatment of industrial wastewaters, but these methods also have certain limitations. Therefore, there is an urgent need to develop such eco-friendly and cost-effective biological treatment methods, which can effectively remove the dye from industrial wastewaters for the safety of environment, as well as human and animal health.

  1. Transcriptionally active and inactive genes are similarly modified by chemical carcinogens or X-ray in normal human fibroblasts

    International Nuclear Information System (INIS)

    Chemical carcinogens and ionizing radiation induce DNA modifications and strand breaks in cells. This damage is reported to be affected by chromatin proteins or chromatin of a higher structure order. To compare the sensitivity of transcriptionally active and inactive genes on chromatin toward DNA-damaging agents, we treated normal human fibroblasts (WI-38) cells with N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), X-ray, 4-hydroxyaminoquinoline 1-oxide or N-acetoxy-2-acetylaminofluorene, and high molecular weight DNA was isolated. After digestion with EcoRI to completion, the DNA was electrophoresed on an alkaline agarose gel, blotted on a nitrocellulose filter and hybridized with a transcriptionally active gene probe (human type I(α2) procollagen gene) or an inactive gene probe (human β-globin gene). The results show that both genes are similarly modified by these agents. Repair of DNA damage caused by MNNG also occurred similarly in collagen and β-globin genes after removal of MNNG. (Auth.)

  2. Excimer UV curing in printing

    International Nuclear Information System (INIS)

    It is the aim of this study to investigate the potential of 308 run excimer UV curing in web and sheet fed offset printing and to discuss its present status. Using real-time FTIR-ATR and stationary or pulsed monochromatic (313 nm) irradiation chemical and physical factors affecting the curing speed of printing inks such as nature and concentration of photo-initiators, reactivity of the ink binding system, ink thickness and pigmentation, irradiance in the curing plane, oxygen concentration and nitrogen inerting, multiple pulse exposure, the photochemical dark reaction and temperature dependence were studied. The results were used to select optimum conditions for excimer UV curing in respect to ink reactivity, nitrogen inerting and UV exposure and to build an excimer UV curing unit consisting of two 50 W/cm 308 run excimer lamps, power supply, cooling and inerting unit. The excimer UV curing devices were tested under realistic conditions on a web offset press zirkon supra forte and a sheet fed press Heidelberg GTO 52. Maximum curing speeds of 300 m/min in web offset and 8000 sheets per hour in sheet fed offset were obtained

  3. Evaluation of human health risks posed by carcinogenic and non-carcinogenic multiple contaminants associated with consumption of fish from Taihu Lake, China.

    Science.gov (United States)

    Yu, Yingxin; Wang, Xinxin; Yang, Dan; Lei, Bingli; Zhang, Xiaolan; Zhang, Xinyu

    2014-07-01

    The present study estimated the human daily intake and uptake of organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), polycyclic aromatic hydrocarbons (PAHs), and toxic trace elements [mercury (Hg), chromium (Cr), cadmium (Cd), and arsenic (As)] due to consumption of fish from Taihu Lake, China, and the associated potential health risks posed by these contaminants. The health risks posed by the contaminants were assessed using a risk quotient of the fish consumption rate to the maximum allowable fish consumption rate considering the contaminants for carcinogenic and non-carcinogenic effect endpoints. The results showed that fish consumption would not pose non-cancer risks. However, some species would cause a cancer risk. Relative risks of the contaminants were calculated to investigate the contaminant which posed the highest risk to humans. As a result, in view of the contaminants for carcinogenic effects, As was the contaminant which posed the highest risk to humans. However, when non-carcinogenic effects of the contaminants were considered, Hg posed the highest risk. The risk caused by PBDEs was negligible. The results demonstrated that traditional contaminants, such as As, Hg, DDTs (dichlorodiphenyltrichloroethane and its metabolites), and PCBs, require more attention in Taihu Lake than the other target contaminants. PMID:24727049

  4. Evaluation of human health risks posed by carcinogenic and non-carcinogenic multiple contaminants associated with consumption of fish from Taihu Lake, China.

    Science.gov (United States)

    Yu, Yingxin; Wang, Xinxin; Yang, Dan; Lei, Bingli; Zhang, Xiaolan; Zhang, Xinyu

    2014-07-01

    The present study estimated the human daily intake and uptake of organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), polycyclic aromatic hydrocarbons (PAHs), and toxic trace elements [mercury (Hg), chromium (Cr), cadmium (Cd), and arsenic (As)] due to consumption of fish from Taihu Lake, China, and the associated potential health risks posed by these contaminants. The health risks posed by the contaminants were assessed using a risk quotient of the fish consumption rate to the maximum allowable fish consumption rate considering the contaminants for carcinogenic and non-carcinogenic effect endpoints. The results showed that fish consumption would not pose non-cancer risks. However, some species would cause a cancer risk. Relative risks of the contaminants were calculated to investigate the contaminant which posed the highest risk to humans. As a result, in view of the contaminants for carcinogenic effects, As was the contaminant which posed the highest risk to humans. However, when non-carcinogenic effects of the contaminants were considered, Hg posed the highest risk. The risk caused by PBDEs was negligible. The results demonstrated that traditional contaminants, such as As, Hg, DDTs (dichlorodiphenyltrichloroethane and its metabolites), and PCBs, require more attention in Taihu Lake than the other target contaminants.

  5. Licochalcone A, a Polyphenol Present in Licorice, Suppresses UV-Induced COX-2 Expression by Targeting PI3K, MEK1, and B-Raf

    Directory of Open Access Journals (Sweden)

    Nu Ry Song

    2015-02-01

    Full Text Available Licorice is a traditional botanical medicine, and has historically been commonly prescribed in Asia to treat various diseases. Glycyrrhizin (Gc, a triterpene compound, is the most abundant phytochemical constituent of licorice. However, high intake or long-term consumption of Gc has been associated with a number of side effects, including hypertension. However, the presence of alternative bioactive compounds in licorice with anti-carcinogenic effects has long been suspected. Licochalcone A (LicoA is a prominent member of the chalcone family and can be isolated from licorice root. To date, there have been no reported studies on the suppressive effect of LicoA against solar ultraviolet (sUV-induced cyclooxygenase (COX-2 expression and the potential molecular mechanisms involved. Here, we show that LicoA, a major chalcone compound of licorice, effectively inhibits sUV-induced COX-2 expression and prostaglandin E2 PGE2 generation through the inhibition of activator protein 1 AP-1 transcriptional activity, with an effect that is notably more potent than Gc. Western blotting analysis shows that LicoA suppresses sUV-induced phosphorylation of Akt/ mammalian target of rapamycin (mTOR and extracellular signal-regulated kinases (ERK1/2/p90 ribosomal protein S6 kinase (RSK in HaCaT cells. Moreover, LicoA directly suppresses the activity of phosphoinositide 3-kinase (PI3K, mitogen-activated protein kinase kinase (MEK1, and B-Raf, but not Raf-1 in cell-free assays, indicating that PI3K, MEK1, and B-Raf are direct molecular targets of LicoA. We also found that LicoA binds to PI3K and B-Raf in an ATP-competitive manner, although LicoA does not appear to compete with ATP for binding with MEK1. Collectively, these results provide insight into the biological action of LicoA, which may have potential for development as a skin cancer chemopreventive agent.

  6. Comparison of the expression profiles induced by genotoxic and nongenotoxic carcinogens in rat liver

    Energy Technology Data Exchange (ETDEWEB)

    Ellinger-Ziegelbauer, Heidrun [Bayer Healthcare AG, Department of Molecular and Genetic Toxicology, Aprather Weg 18a, 42096 Wuppertal (Germany)]. E-mail: heidrun.ellinger-ziegelbauer@bayerhealthcare.com; Stuart, Barry [Bayer Crop Science, Department of Toxicology, Stilwell, KS (United States); Wahle, Brad [Bayer Crop Science, Department of Toxicology, Stilwell, KS (United States); Bomann, Werner [Bayer Crop Science, Department of Toxicology, Stilwell, KS (United States); Ahr, Hans Juergen [Bayer Healthcare AG, Department of Molecular and Genetic Toxicology, Aprather Weg 18a, 42096 Wuppertal (Germany)

    2005-08-04

    Application of recently developed gene expression techniques using microarrays in toxicological studies (toxicogenomics) facilitate the interpretation of a toxic compound's mode of action and may also allow the prediction of selected toxic effects based on gene expression changes. In order to test this hypothesis, we investigated whether carcinogens at doses known to induce liver tumors in the 2-year rat bioassay deregulate characteristic sets of genes in a short term in vivo study and whether these deregulated genes represent defined biological pathways. Male Wistar rats were dosed with the four nongenotoxic hepatocarcinogens methapyrilene (MPy, 60 mg/kg/day), diethylstilbestrol (DES, 10 mg/kg/day), Wy-14643 (Wy, 60 mg/kg/day), and piperonylbutoxide (PBO, 1200 mg/kg/day). After 1, 3, 7, and 14 days, the livers were taken for histopathological evaluation and for analysis of the gene expression profiles on Affymetrix RG{sub U}34A arrays. The expression profile of the four nongenotoxic carcinogens were compared to the profiles of the four genotoxic carcinogens 2-nitrofluorene (2-NF), dimethylnitrosamine (DMN), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), and aflatoxin B1 (AB1) from a similar study reported previously. By using statistical and clustering tools characteristically deregulated genes were extracted and functionally classified. Distinct cellular pathways were affected by the nongenotoxic carcinogens compared to the genotoxic carcinogens which at least partly correlated with the two-stage model of carcinogenesis. Characteristic to genotoxic carcinogens were a DNA damage response and the activation of proliferative and survival signaling. Nongenotoxic carcinogens showed responses to oxidative DNA or protein damage, as well as cell cycle progression and signs of regeneration. Many of the gene alterations found with the nongenotoxic carcinogens imply compound-specific mechanisms. Although neither a single gene nor a single pathway will be

  7. Use of the modified Ames test as an indicator of the carcinogenicity of residual aromatic extracts

    Energy Technology Data Exchange (ETDEWEB)

    Boogaard, P.; Hedelin, A.; Riley, A.; Rushton, E.; Vaissiere, M.; Minsavage, G.; Rohde, A.; Dalbey, W.

    2013-01-15

    Existing data demonstrate that residual aromatic extracts (RAEs) can be either carcinogenic or non-carcinogenic. CONCAWE had previously concluded that 'Although limited data available indicate that some RAEs are weakly carcinogenic, it is not possible to provide a general recommendation. Classify on a case-by-case basis' (CONCAWE 2005). Therefore CONCAWE's Health/Toxicology Subgroup (H/TSG) has developed a proposal for the use of the modified Ames test as a short-term predictive screening tool for decisions on the classification of RAEs for carcinogenicity. The relationship between RAE chemistry and carcinogenic potential is not as well understood as it is for some other categories of substances, e.g. Other Lubricant Base Oils (OLBO). However, a correlation has been found between the results of the skin carcinogenicity bioassay and the mutagenicity index (MI) obtained from the modified Ames test. Data supporting this correlation are summarised in this report. The H/TSG confirmed that the modified Ames test can be used as a predictive screening tool and that a cut-off value can be established to make a distinction between carcinogenic and non-carcinogenic products. RAEs with a MI > 0.4 demonstrated carcinogenic potential upon dermal application to mouse skin with chronic exposure. RAEs with a MI > 0.4 did not demonstrate a carcinogenic potential. To justify the use of the modified Ames test with RAEs, additional analysis of the repeatability of the test with RAEs was required. With this objective, CONCAWE sponsored a round robin study with different samples of RAEs from member companies, at three different laboratories. The repeatability demonstrated in the round robin study with RAEs support the proposed use of the modified Ames test. As part of the tools available for use by member companies, the H/TSG proposed a standard operating procedure (SOP) (included as an Appendix to this report) on the conduct of the modified Ames test with RAEs. The H

  8. Inhalation toxicity and carcinogenicity studies of cobalt sulfate.

    Science.gov (United States)

    Bucher, J R; Hailey, J R; Roycroft, J R; Haseman, J K; Sills, R C; Grumbein, S L; Mellick, P W; Chou, B J

    1999-05-01

    Cobalt sulfate is a water-soluble cobalt salt with a variety of industrial and agricultural uses. Several cobalt compounds have induced sarcomas at injection sites in animals, and reports have suggested that exposure to cobalt-containing materials may cause lung cancer in humans. The present studies were done because no adequate rodent carcinogenicity studies had been performed with a soluble cobalt salt using a route relevant to occupational exposures. Groups of 50 male and 50 female F344/N rats and B6C3F1 mice were exposed to aerosols containing 0, 0.3, 1.0, or 3.0 mg/m3 cobalt sulfate hexahydrate, 6 h/day, 5 days/week, for 104 weeks. Survival and body weights of exposed rats and mice were generally unaffected by the exposures. In rats, proteinosis, alveolar epithelial metaplasia, granulomatous alveolar inflammation, and interstitial fibrosis were observed in the lung in all exposed groups. Nonneoplastic lesions of the nose and larynx were also attributed to exposure to all concentrations of cobalt sulfate. In 3.0 mg/m3 male rats and in female rats exposed to 1.0 or 3.0 mg/m3, the incidences of alveolar/bronchiolar neoplasms were increased over those in the control groups. Lung tumors occurred with significant positive trends in both sexes. The incidences of adrenal pheochromocytoma in 1.0 mg/m3 male rats and in 3.0 mg/m3 female rats were increased. Nonneoplastic lesions of the respiratory tract were less severe in mice than in rats. In mice, alveolar/bronchiolar neoplasms in 3.0 mg/m3 males and females were greater than those in the controls, and lung tumors occurred with significantly positive trends. Male mice had liver lesions consistent with a Helicobacter hepaticus infection. Incidences of liver hemangiosarcomas were increased in exposed groups of male mice; however, because of the infection, no conclusion could be reached concerning an association between liver hemangiosarcomas and cobalt sulfate. In summary, exposure to cobalt sulfate by inhalation

  9. Determination of Hexavalent Chromium (Cr(VI)) Concentrations via Ion Chromatography and UV-Vis Spectrophotometry in Samples Collected from Nacogdoches Wastewater Treatment Plant, East Texas (USA)

    OpenAIRE

    Onchoke, Kefa K.; Sasu, Salomey A.

    2016-01-01

    The concentration of hexavalent chromium (Cr(VI)), a toxic environmental pollutant and carcinogen, was determined in samples collected from Nacogdoches Wastewater Treatment Plant (NWWTP) using ion chromatography and UV-visible spectrophotometry (IC, UV-Vis). On reaction with 1,5-diphenylcarbazide (DPC) Cr+6 forms a 1,5-diphenylcarbazide-Cr(VI) complex, which is then analyzed at 530 nm and 540 nm, respectively. Via ion chromatography Cr(VI) concentrations were in the range of 0.00190±0.0020 an...

  10. Plasmon-enhanced UV photocatalysis

    Energy Technology Data Exchange (ETDEWEB)

    Honda, Mitsuhiro; Saito, Yuika, E-mail: yuika@ap.eng.osaka-u.ac.jp; Kawata, Satoshi [Department of Applied Physics, Osaka University, Suita, Osaka 565-0871 (Japan); Kumamoto, Yasuaki [Nanophotonics Laboratory, RIKEN, Wako, Saitama 351-0198 (Japan); Taguchi, Atsushi [Nanophotonics Laboratory, RIKEN, Wako, Saitama 351-0198 (Japan); Department of Mechanical Systems Engineering, School of Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588 (Japan)

    2014-02-10

    We report plasmonic nanoparticle enhanced photocatalysis on titanium dioxide (TiO{sub 2}) in the deep-UV range. Aluminum (Al) nanoparticles fabricated on TiO{sub 2} film increases the reaction rate of photocatalysis by factors as high as 14 under UV irradiation in the range of 260–340 nm. The reaction efficiency has been determined by measuring the decolorization rate of methylene blue applied on the TiO{sub 2} substrate. The enhancement of photocatalysis shows particle size and excitation wavelength dependence, which can be explained by the surface plasmon resonance of Al nanoparticles.

  11. Growth of a mat-forming photograph in the presence of UV radiation

    Science.gov (United States)

    Pierson, Beverly K.; Ruff, A. L.

    1989-01-01

    Knowledge of the survival and growth of microorganisms in the presence of ultraviolet radiation is important for understanding the potential for life to exist in environments exposed to high fluxes of UV radiation. The growth of a mat-forming phototrophic prokaryote, Chloroflexus aurantiacus, was examined in the presence of continuous high UV irradiation under otherwise optimal growth conditions. Evidence was sought for an intrinsic ability to grow in the presence of UV radiation in a carefully chosen organism known to be unusually resistant to UV radiation, of ancient lineage among the phototrophs, to resemble ancient microfossils from the Precambrian, and to be a mat-former. It was assumed that even a high intrinsic UV resistance would be inadequate for survival and growth in the presence of very high UV fluxes, and iron (Fe3+) was selected as a common, abundant UV-absorbing substance that might protest microorganisms growing in or under iron-bearing sediments. The effectiveness of Fe(3+) was tested as a UV protective agent at low concentrations in thin layers. It was concluded that intrinsic UV resistance in some organisms may account for growth, not just survival, of these organisms when exposed to high UV fluxes under otherwise optimal growth conditions in an anoxic environment. It was also concluded that Fe(3+) bearing sediments of 1 mm or less in thickness may provide an adequate shield against high UV fluxes permitting the growth of microorganisms just below their surface. As long as growth conditions were met, then the evolution and development of microorganisms would not be hampered by high UV fluxes impinging upon the surface of iron-bearing sediments.

  12. Qualitative and quantitative approaches in the dose-response assessment of genotoxic carcinogens.

    Science.gov (United States)

    Fukushima, Shoji; Gi, Min; Kakehashi, Anna; Wanibuchi, Hideki; Matsumoto, Michiharu

    2016-05-01

    Qualitative and quantitative approaches are important issues in field of carcinogenic risk assessment of the genotoxic carcinogens. Herein, we provide quantitative data on low-dose hepatocarcinogenicity studies for three genotoxic hepatocarcinogens: 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) and N-nitrosodiethylamine (DEN). Hepatocarcinogenicity was examined by quantitative analysis of glutathione S-transferase placental form (GST-P) positive foci, which are the preneoplastic lesions in rat hepatocarcinogenesis and the endpoint carcinogenic marker in the rat liver medium-term carcinogenicity bioassay. We also examined DNA damage and gene mutations which occurred through the initiation stage of carcinogenesis. For the establishment of points of departure (PoD) from which the cancer-related risk can be estimated, we analyzed the above events by quantitative no-observed-effect level and benchmark dose approaches. MeIQx at low doses induced formation of DNA-MeIQx adducts; somewhat higher doses caused elevation of 8-hydroxy-2'-deoxyquanosine levels; at still higher doses gene mutations occurred; and the highest dose induced formation of GST-P positive foci. These data indicate that early genotoxic events in the pathway to carcinogenesis showed the expected trend of lower PoDs for earlier events in the carcinogenic process. Similarly, only the highest dose of IQ caused an increase in the number of GST-P positive foci in the liver, while IQ-DNA adduct formation was observed with low doses. Moreover, treatment with DEN at low doses had no effect on development of GST-P positive foci in the liver. These data on PoDs for the markers contribute to understand whether genotoxic carcinogens have a threshold for their carcinogenicity. The most appropriate approach to use in low dose-response assessment must be approved on the basis of scientific judgment.

  13. Chromosomal Integrity after UV Irradiation Requires FANCD2-Mediated Repair of Double Strand Breaks

    Science.gov (United States)

    Federico, María Belén; Vallerga, María Belén; Radl, Analía; Paviolo, Natalia Soledad; Bocco, José Luis; Di Giorgio, Marina; Soria, Gastón; Gottifredi, Vanesa

    2016-01-01

    Fanconi Anemia (FA) is a rare autosomal recessive disorder characterized by hypersensitivity to inter-strand crosslinks (ICLs). FANCD2, a central factor of the FA pathway, is essential for the repair of double strand breaks (DSBs) generated during fork collapse at ICLs. While lesions different from ICLs can also trigger fork collapse, the contribution of FANCD2 to the resolution of replication-coupled DSBs generated independently from ICLs is unknown. Intriguingly, FANCD2 is readily activated after UV irradiation, a DNA-damaging agent that generates predominantly intra-strand crosslinks but not ICLs. Hence, UV irradiation is an ideal tool to explore the contribution of FANCD2 to the DNA damage response triggered by DNA lesions other than ICL repair. Here we show that, in contrast to ICL-causing agents, UV radiation compromises cell survival independently from FANCD2. In agreement, FANCD2 depletion does not increase the amount of DSBs generated during the replication of UV-damaged DNA and is dispensable for UV-induced checkpoint activation. Remarkably however, FANCD2 protects UV-dependent, replication-coupled DSBs from aberrant processing by non-homologous end joining, preventing the accumulation of micronuclei and chromatid aberrations including non-homologous chromatid exchanges. Hence, while dispensable for cell survival, FANCD2 selectively safeguards chromosomal stability after UV-triggered replication stress. PMID:26765540

  14. Agent Chameleons: Virtual Agents Real Intelligence

    OpenAIRE

    O'Hare, Gregory; Duffy, Brian; Schoen-Phelan, Bianca; Martin, Alan; Bradley, John

    2003-01-01

    Agent Chameleons provides virtual agents powered by real intelligence, delivering next generation autonomic entities that can seamlessly migrate, mutate and evolve on their journey between and within physical and digital information spaces.

  15. Interacting agents in finance

    NARCIS (Netherlands)

    C. Hommes

    2008-01-01

    Interacting agents in finance represent a behavioural, agent-based approach in which financial markets are viewed as complex adaptive systems consisting of many boundedly rational agents interacting through simple heterogeneous investment strategies, constantly adapting their behaviour in response t

  16. Quantitative structure carcinogenicity relationship for detecting structural alerts in nitroso-compounds

    International Nuclear Information System (INIS)

    Prevention of environmentally induced cancers is a major health problem of which solutions depend on the rapid and accurate screening of potential chemical hazards. Lately, theoretical approaches such as the one proposed here - Quantitative Structure-Activity Relationship (QSAR) - are increasingly used for assessing the risks of environmental chemicals, since they can markedly reduce costs, avoid animal testing, and speed up policy decisions. This paper reports a QSAR study based on the Topological Substructural Molecular Design (TOPS-MODE) approach, aiming at predicting the rodent carcinogenicity of a set of nitroso-compounds selected from the Carcinogenic Potency Data Base (CPDB). The set comprises nitrosoureas (14 chemicals), N-nitrosamines (18 chemicals) C-nitroso-compounds (1 chemical), nitrosourethane (1 chemical) and nitrosoguanidine (1 chemical), which have been bioassayed in male rat using gavage as the route of administration. Here we are especially concerned in gathering the role of both parameters on the carcinogenic activity of this family of compounds. First, the regression model was derived, upon removal of one identified nitrosamine outlier, and was able to account for more than 84% of the variance in the experimental activity. Second, the TOPS-MODE approach afforded the bond contributions - expressed as fragment contributions to the carcinogenic activity - that can be interpreted and provide tools for better understanding the mechanisms of carcinogenesis. Finally, and most importantly, we demonstrate the potentialities of this approach towards the recognition of structural alerts for carcinogenicity predictions

  17. Partial lipectomy reduces dimethylhydrazine-induced carcinogenic initiation in the colon of rats

    International Nuclear Information System (INIS)

    This study investigated whether visceral adipose tissue directly modulates the development of preneoplastic lesions in the colon of carcinogen-treated rats. Wistar rats (n = 64) were randomly assigned to 8 experimental groups in two experiments. In one experiment, 32 rats were exposed or not to either carcinogen treatment (dimethylhydrazine, DMH; 125 mg/kg) or high-fat diet (standard chow enriched with 14% lard) or both for 56 days. In a second experiment, 32 rats were exposed to a carcinogen or they underwent partial lipectomy or both for 30 days (partial lipectomy groups underwent ablation of mesenteric and parametrial fat pads, whereas sham groups did not; all rats were fed with standard chow). Colon was collected for histopathological analysis. After 56 experimental days a high-fat diet increased carcinogenic mutations in the colonic epithelia. Partial lipectomy reduced weight gain in carcinogen-exposed rats and decreased the de novo formation of mesenteric and parametrial fat pads. Partial lipectomy significantly inhibited the mutational process after 30 days: there were fewer colonic preneoplastic lesions and less proliferation, apoptosis, and inflammation. These data suggest that visceral adipose tissue promotes colon carcinogenesis and enhances the establishment and expansion of genetically mutated cells in colonic epithelia

  18. Skin protection against UV light by dietary antioxidants.

    Science.gov (United States)

    Fernández-García, Elisabet

    2014-09-01

    There is considerable interest in the concept of additional endogenous photoprotection by dietary antioxidants. A number of efficient micronutrients are capable of contributing to the prevention of UV damage in humans. These compounds protect molecular targets by scavenging reactive oxygen species, including excited singlet oxygen and triplet state molecules, and also modulate stress-dependent signaling and/or suppress cellular and tissue responses like inflammation. Micronutrients present in the diet such as carotenoids, vitamins E and C, and polyphenols contribute to antioxidant defense and may also contribute to endogenous photoprotection. This review summarizes the literature concerning the use of dietary antioxidants as systemic photoprotective agents towards skin damage induced by UVA and UVB. Intervention studies in humans with carotenoid-rich diets have shown photoprotection. Interestingly, rather long treatment periods (a minimum of 10 weeks) were required to achieve this effect. Likewise, dietary carotenoids exert their protective antioxidant function in several in vitro and in vivo studies when present at sufficiently high concentration. A combination of vitamins E and C protects the skin against UV damage. It is suggested that daily consumption of dietary polyphenols may provide efficient protection against the harmful effects of solar UV radiation in humans. Furthermore, the use of these micronutrients in combination may provide an effective strategy for protecting human skin from damage by UV exposure.

  19. Production of thymine glycols in DNA by radiation and chemical carcinogens as detected by a monoclonal antibody.

    OpenAIRE

    Leadon, S A

    1987-01-01

    In order to understand the role in carcinogenesis of damage indirectly induced by chemical carcinogens, it is important to identify the primary DNA lesions. We have measured the formation and repair of one type of DNA modification, 5,6-dihydroxydihydrothymine (thymine glycol), following exposure of cultured human cells to the carcinogens N-hydroxy-2-naphthylamine or benzo(a)pyrene. The efficiency of production of thymine glycols in DNA by these carcinogens was compared to that by ionizing rad...

  20. UV-photoactivation technique for size and shape controlled synthesis and annealing of stable gold nanoparticles in micelle

    Indian Academy of Sciences (India)

    Madhuri Mandal; Subrata Kundu; Sujit Kumar Ghosh; Tarasankar Pal

    2002-11-01

    Gold nanoparticles of different sizes and shapes have been prepared by UV-photoactivation technique using the micelle TX-100 (poly(oxyethylene) iso-octylphenyl ether) as reducing agent, stabilizing agent as well as template which has been authenticated from the plasmon absorption band and TEM picture. The heating effect on those gold nanoparticles has also been studied.

  1. Identifying carcinogenic activity of methylated and non-methylated polycyclic aromatic hydrocarbons (PAHs) through electronic and topological indices

    CERN Document Server

    Braga, R S; Barone, P M V B

    2000-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are a class of planar molecules, abundant in urban environment, which can induce chemical carcinogenesis. Their carcinogenic power varies in a large range, from very strong carcinogens to inactive ones. In a previous study, we proposed a methodology to identify the PAHs carcinogenic activity exploring electronic and topological indices. In the present work, we show that it is possible to simplify that methodology and expand its applicability to include methylated PAHs compounds. Using very simple rules, we can predict their carcinogenic activity with high accuracy (approx 89%).

  2. Physics of Electrodeless UV Lamps and Applications of UV Radiation

    Science.gov (United States)

    Cekic, Miodrag; Ruckman, Mark

    2004-12-01

    Electrodeless discharge microwave powered ultraviolet limps are a special class of high power incoherent UV sources, conceptualized forty years ago for industrial processing applications. Because of the nonimaging character of the applications, the need for measuring averaged properties of the lamps' exceeds the motivation to obtain detailed space-resolved discharge parameters. This writing discusses measurements of the average plasma temperature of a 5.8kW high pressure mercury bulb and a XeCl* excimer bulb driven by the microwaves of the same power. First method is based on the black body radiance fit to the self-absorbed 185nm and 254nm mercury lines. The second method is essentially Boltzmann plot method applied to the roto-vibrational levels of B1/2 - X1/2 XeCl* molecular transition with a maximum at 308nm. We also present a procedure for evaluation of effectiveness of different bulb spectra to the given UV curing chemistry system independent from the Beer-Lambert law. Conversely, the procedure can be used for the optimization of the chemistry to the chosen UV lamp radiance spectrum.

  3. The Anatomic Pathology Evaluation of Liver with Diethylinitrosamine Treated via Intraperitoneal Injection Singly and Peros for 90 Days Carcinogenicity Study in F344 Rats

    Institute of Scientific and Technical Information of China (English)

    LI Shan-shan; KANEKO Toyozo; XING Rui-chang; WANG Xiu-wen; LI Bo; ZHANG Lin; LI Bao-wen; LANG Shu-hui; YANG Yan-wei; ZHANG Di; ZHANG Yang; NARAMA Isao; KAWAYI Zeshow

    2008-01-01

    Objective:To establish the integrity experiment method of short(medium)-term carcinogenicity test pursuant to GLP, make into relative SOP and improve the safeguard in the center.Methods:Diethylinitrosamine(DEN) is known as carcinogenic agent,whose target organ is liver. Using the two-stage carcinogenesis test method, DEN was treated to F344 rats via intraperitoneal injection singly(200 mg/kg), and peros administrated for 90 days(10 ppm). The liver in any group rat will be examined by light microscopy.Results:In pathologic examination, no liver cell tumor was shown in the livers of the rats that were singly treated with a carcinogenic chemical-DEN.Foci of cellular alteration were observed in the livers of these rats. The proliferation lesions of liver from slight to seveity(foci of cellular alteration-hepatocelluar adenoma-hepatocellular carcinoma)were observed in the livers of the rats which exposed peros to a low dose of DEN for 90 days after initiation by a single intraperitoneal injection. The incidence of hepatocelluar tumor was 35% in male animal,which was not shown in the liver of female rat.Conclusion:For current results, it may be possible that low-dose DEN acts as a promotor of hepatocelluar tumor if it was exposed in a population for a long time. It is considered that male hormone has a synergistic effect on hepatocelluar tumor development of DEN. This two-stage carcinogenesis test might be a new model for the study of drug induced and promoted carcinogenesis,which could be used to evaluate the carcinogenesis of chemical compound fast.

  4. Factors modifying sensitivity to carcinogens and the problem of threshold in carcinogenesis

    International Nuclear Information System (INIS)

    Maximum allowable concentrations of chemical carcinogens and dose rates of ionizing radiation have been under extensive study both experimentally and epidemiologically. The problem of the carcinogenic hazards of low-level radiation is a very difficult one: in epidemiological studies it is hard to take into account the many factors (e.g. diseases, diet, genetic peculiarities) that may affect sensitivity to radiation; in experimental studies it is hard to extrapolate with accuracy from one species to another or from the individual threshold to that of the whole population. Age, enzyme activity, sex, and DNA repair capability also modify sensitivity to radiation; when factors such as these are better understood it is expected that epidemiological studies will give a solution that allows estimation of the carcinogenic risk from low-level radiation and hence establishment of a threshold dose. (author)

  5. [Mapping of carcinogens in the chemical production industry in the province of Ferrara].

    Science.gov (United States)

    Maldotti, M; Spagnolo, M R; Minisci, S; De Rosa, E

    2008-01-01

    This study consists in the reconnaissance of the carcinogenic risk in some processing in Ferrara. The main object is to know, to estimate and to verify the diffusion of the carcinogenic substances and to estimate the number of the exposed or potentially exposed workers. The study has interested the synthesis chemistry and polymer production, woodworking, welding on stainless steel and chromium conversion coating and chrome electroplating. The research has involved 54 factories and 436 workers estimated exposed or potentially exposed to carcinogenic substances. The survey has consisted of inspections in the working places, collection of exposure data, control of the precautionary measures and exposure determination in the case of stainless steel welding. The smallest factories had less knowledge of the risk and for this reason it is necessary to keep constant attention.

  6. Cell-mediated mutagenesis and cell transformation of mammalian cells by chemical carcinogens

    International Nuclear Information System (INIS)

    We have developed a cell-mediated mutagenesis assay in which cells with the appropriate markers for mutagenesis are co-cultivated with either lethally irradiated rodent embryonic cells that can metabolize carcinogenic hydrocarbons or with primary rat liver cells that can metabolize chemicals carcinogenic to the liver. During co-cultivation, the reactive metabolites of the procarcinogen appear to be transmitted to the mutable cells and induce mutations in them. Assays of this type make it possible to demonstrate a relationship between carcinogenic potency of the chemicals and their ability to induce mutations in mammalian cells. In addition, by simultaneously comparing the frequencies of transformation and mutation induced in normal diploid hamster cells by benzo(a)pyrene (BP) and one of its metabolites, it is possible to estimate the genetic target size for cell transformation in vitro

  7. Detection of mutagenic/carcinogenic compounds in unused and used motor oils.

    Science.gov (United States)

    Pasquini, R; Monarca, S

    1983-12-15

    The discharge of used motor oils in the environment poses public health problems because of the mutagenic/carcinogenic compounds in them. Among these hazardous chemicals, polycyclic aromatic hydrocarbons (PAH) are of particular interest since the carcinogenic properties of some of them are known. The authors have applied the Salmonella/microsome test, coupled with two preparation methods of samples, to motor oils of different brands, both before and after use in car petrol engines. A PAH determination method was also studied. The results showed the unused motor oils to be nonmutagenic and to contain traces of PAH, while the used motor oils of the samples taken according to both preparation methods were highly mutagenic and contained a much higher quantity of mutagenic/carcinogenic PAH.

  8. An Overview of Carcinogenic Heavy Metal: Molecular Toxicity Mechanism and Prevention

    Science.gov (United States)

    Kim, Hyun Soo; Kim, Yeo Jin; Seo, Young Rok

    2015-01-01

    Almost all heavy metals are serious toxicants as carcinogens. However, due to their chemical and physiological properties, heavy metals are useful in industrial areas including alloy, smelting and production of commercial products. Such applications increase the opportunity for heavy metal exposure. Waste from industrial processes is also a major source of environmental contamination and accumulation in the human body. Arsenic, cadmium, chromium, and nickel are classified as group 1 carcinogens by the International Agency for Research on Cancer, and are utilized commercially. In this review, we used molecular pathway analysis to understand the toxicity and carcinogenic mechanisms of these metals. Our analyzed data showed that above-mentioned metallic substances induce oxidative stress, DNA damage, and cell death processes, resulting in increase the risk of cancer and cancer-related diseases. Thus, we might think phytochelatin molecules and antioxidative phytochemical substances are helpful for prevention of heavy metal-induced cancer. PMID:26734585

  9. UV-induced DNA damage promotes resistance to the biotrophic pathogen Hyaloperonospora parasitica in Arabidopsis.

    Science.gov (United States)

    Kunz, Bernard A; Dando, Paige K; Grice, Desma M; Mohr, Peter G; Schenk, Peer M; Cahill, David M

    2008-10-01

    Plant innate immunity to pathogenic microorganisms is activated in response to recognition of extracellular or intracellular pathogen molecules by transmembrane receptors or resistance proteins, respectively. The defense signaling pathways share components with those involved in plant responses to UV radiation, which can induce expression of plant genes important for pathogen resistance. Such intriguing links suggest that UV treatment might activate resistance to pathogens in normally susceptible host plants. Here, we demonstrate that pre-inoculative UV (254 nm) irradiation of Arabidopsis (Arabidopsis thaliana) susceptible to infection by the biotrophic oomycete Hyaloperonospora parasitica, the causative agent of downy mildew, induces dose- and time-dependent resistance to the pathogen detectable up to 7 d after UV exposure. Limiting repair of UV photoproducts by postirradiation incubation in the dark, or mutational inactivation of cyclobutane pyrimidine dimer photolyase, (6-4) photoproduct photolyase, or nucleotide excision repair increased the magnitude of UV-induced pathogen resistance. In the absence of treatment with 254-nm UV, plant nucleotide excision repair mutants also defective for cyclobutane pyrimidine dimer or (6-4) photoproduct photolyase displayed resistance to H. parasitica, partially attributable to short wavelength UV-B (280-320 nm) radiation emitted by incubator lights. These results indicate UV irradiation can initiate the development of resistance to H. parasitica in plants normally susceptible to the pathogen and point to a key role for UV-induced DNA damage. They also suggest UV treatment can circumvent the requirement for recognition of H. parasitica molecules by Arabidopsis proteins to activate an immune response.

  10. Cytotoxic, mutagenic and carcinogenic properties of ultraviolet radiation : shining light on photolesions

    OpenAIRE

    Jans, Judith

    2003-01-01

    textabstractExposure to ultraviolet light (UV light) poses a serieus threat to human health. An altered life style (holidays in the sun, tanning devices) has led to increased exposure to UV light in the Western population. UV light damages the DNA, the carrier of genetic information, which can result in permanent alterations in the genome and, ultimately, cancer. The majority of the DNA lesions induced by UV light consists of cyclobutane pyrimidine dimers (CPDs) and pyrimidine-(6,4)-pyrimidon...

  11. Embryonic turkey liver: activities of biotransformation enzymes and activation of DNA-reactive carcinogens

    Energy Technology Data Exchange (ETDEWEB)

    Perrone, Carmen E.; Duan, Jian Dong; Jeffrey, Alan M.; Williams, Gary M. [New York Medical College, Department of Pathology, Valhalla (United States); Ahr, Hans-Juergen; Schmidt, Ulrich [Bayer AG, Institute of Toxicology, Wuppertal (Germany); Enzmann, Harald H. [Federal Institute for Drugs and Medical Devices, Bonn (Germany)

    2004-10-01

    Avian embryos are a potential alternative model for chemical toxicity and carcinogenicity research. Because the toxic and carcinogenic effects of some chemicals depend on bioactivation, activities of biotransformation enzymes and formation of DNA adducts in embryonic turkey liver were examined. Biochemical analyses of 22-day in ovoturkey liver post-mitochondrial fractions revealed activities of the biotransformation enzymes 7-ethoxycoumarin de-ethylase (ECOD), 7-ethoxyresorufin de-ethylase (EROD), aldrin epoxidase (ALD), epoxide hydrolase (EH), glutathione S-transferase (GST), and UDP-glucuronyltransferase (GLUT). Following the administration of phenobarbital (24 mg/egg) on day 21, enzyme activities of ECOD, EROD, ALD, EH and GLUT, but not of GST, were increased by two-fold or higher levels by day 22. In contrast, acute administration of 3-methylcholanthrene (5 mg/egg) induced only ECOD and EROD activities. Bioactivation of structurally diverse pro-carcinogens was also examined using {sup 32}P-postlabeling for DNA adducts. In ovoexposure of turkey embryos on day 20 of gestation to 2-acetylaminofluorene (AAF), 4,4'-methylenebis(2-chloroaniline) (MOCA), benzo[a]pyrene (BaP), and 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) resulted in the formation of DNA adducts in livers collected by day 21. Some of the DNA adducts had {sup 32}P-postlabeling chromatographic migration patterns similar to DNA adducts found in livers from Fischer F344 rats exposed to the same pro-carcinogens. We conclude that 21-day embryonic turkey liver is capable of chemical biotransformation and activation of genotoxic carcinogens to form DNA adducts. Thus, turkey embryos could be utilized to investigate potential chemical toxicity and carcinogenicity. (orig.)

  12. Carcinogen-induced DNA repair in nucleotide-permeable Escherichia coli cells. Induction of DNA repair by the carcinogens methyl and ethyl nitrosourea and methyl methanesulfonate.

    Science.gov (United States)

    Thielmann, H W; Vosberg, H P; Reygers, U

    1975-08-15

    Ether-permeabilized (nucleotide-permeable) cells of Escherichia coli show excision repair of their DNA after having been exposed to the carcinogens N-methyl-N-nitrosourea (MeNOUr), N-ethyl-N-nitrosourea (EtNOUr) and methyl methanesulfonate (MeSO2OMe) which are known to bind covalently to DNA. Defect mutations in genes uvrA, uvrB, uvrC, recA, recB, recC and rep did not inhibit this excision repair. Enzymic activities involved in this repair were identified by measuring size reduction of DNA, DNA degradation to acid-soluble nucleotides and repair polymerization. 1. In permeabilized cells methyl and ethyl nitrosourea induced endonucleolytic cleavage of endogenous DNA, as determined by size reduction of denatured DNA in neutral and alkaline sucrose gradients. An enzymic activity from E. coli K-12 cell extracts was purified (greater than 2000-fold) and was found to cleave preferentially methyl-nitrosourea-treated DNA and to convert the methylated supercoiled DNA duplex (RFI) of phage phiX 174 into the nicked circular form. 2. Degradation of alkylated cellular DNA to acid solubility was diminished in a mutant lacking the 5' leads to 3' exonucleolytic activity of DNA polymerase I but was not affected in a mutant which lacked the DNA polymerizing but retained the 5' leads 3' exonucleolytic activity of DNA polymerase I. 3. An easily measurable effect is carcinogen-induced repair polymerization, making it suitable for detection of covalent binding of carcinogens and potentially carcinogenic compounds. PMID:170107

  13. Cytotoxic, mutagenic and carcinogenic properties of ultraviolet radiation : shining light on photolesions

    NARCIS (Netherlands)

    J. Jans (Judith)

    2003-01-01

    textabstractExposure to ultraviolet light (UV light) poses a serieus threat to human health. An altered life style (holidays in the sun, tanning devices) has led to increased exposure to UV light in the Western population. UV light damages the DNA, the carrier of genetic information, which can resul

  14. Direct UV-written integrated optical components

    DEFF Research Database (Denmark)

    Svalgaard, Mikael

    2004-01-01

    Direct UV writing is an emerging method for flexible, low cost fabrication of integrated optical waveguides and components. The performance of UV written components can be similar to that achieved with more elaborate fabrication techniques.......Direct UV writing is an emerging method for flexible, low cost fabrication of integrated optical waveguides and components. The performance of UV written components can be similar to that achieved with more elaborate fabrication techniques....

  15. Photodynamic cytotoxicity of mammalian cells exposed to sunlight-simulating near ultraviolet light in the presence of the carcinogen 7, 12-dimethylbenz(a)anthracene

    International Nuclear Information System (INIS)

    The coal-derived carcinogen 7,12-dimethylbenz(a)anthracene (DMBA), added to cultures of V79 Chinese Hamster, C3H mouse 10T1/2, and human HeLa cells enhanced photolethality induced by the sunlight-simulating emission from Westinghouse Sun Lamps (approximately 290-400 nm) but only in the presence of 02. Treatment of cells with DMBA after irradiation was without lethal effect; the endoperoxide of DMBA was ineffective both before as well as after irradiation, and DMBA incubation before far-UV exposure (254 nm) was protective. Cells rendered photosensitive by incubation with DMBA rapidly lost their sensitivity (in 0C) if incubation in a DMBA-free solution containing serum, but maintained their sensitivity at least for several hours if a serum-free solution was used. Although DMBA enhanced light-induced killing of cells in all phases of the cycle, those undergoing DNA syntheses were preferentially sensitized. The data supported photodynamic lethality due to one or both of the following: (1) the reaction with DNA of either DMBA radicals followed by oxidation, or DMBA-produced single oxygen; or (2) the peroxidation of lysosomal membranes followed by the release of hydrolases including DNAses. As a model system of the combined effects of a fossil-fuel derived polycyclic aromatic hydrocarbon and sunlight, the results with DMBA + near-UV are discussed in the context of altered cell properties (e.g. neoplastic transformation) in sublethally affected cells. (author)

  16. Chemoprevention with Acetylsalicylic Acid, Vitamin D and Calcium Reduces Risk of Carcinogen-induced Lung Tumors

    DEFF Research Database (Denmark)

    Pommergaard, Hans-Christian; Burcharth, Jakob; Rosenberg, J;

    2013-01-01

    Background/Aim: Research has shown that chemoprevention may be effective against the development of lung cancer. The purpose of the present study was to evaluate the effect of oral chemoprevention in a mouse model of tobacco carcinogen-induced lung tumor.......Background/Aim: Research has shown that chemoprevention may be effective against the development of lung cancer. The purpose of the present study was to evaluate the effect of oral chemoprevention in a mouse model of tobacco carcinogen-induced lung tumor....

  17. Low toxicity aromatic diamine curing agents for adhesives

    Energy Technology Data Exchange (ETDEWEB)

    Dorsey, G.F.

    1993-08-24

    Increasing severity of regulations for handling of hazardous materials has led to formulation of adhesives with considerably lowered toxicities for use at the Oak Ridge Y-12 Plant. Fundamental was the development of Asilamine aromatic diamines, a family of liquid aromatic diamines useful as substitutes for methylenedianiline (MDA), a widely used adhesives curing agent. The use of Asilamine has allowed us to continue operations without dealing with expensive measures for regulation of MDA as a carcinogen promulgated by the Occupational Safety and Health Administration (OSHA).

  18. Cremophor EL stimulates mitotic recombination in uvsH//uvsH diploid strain of Aspergillus nidulans

    Directory of Open Access Journals (Sweden)

    Cleverson Busso

    2004-03-01

    Full Text Available Cremophor EL is a solubilizer and emulsifier agent used in the pharmaceutical and foodstuff industries. The solvent is the principal constituent of paclitaxel's clinical formulation vehicle. Since mitotic recombination plays a crucial role in multistep carcinogenesis, the study of the recombinagenic potential of chemical compounds is of the utmost importance. In our research genotoxicity of cremophor EL has been studied by using an uvsH//uvsH diploid strain of Aspergillus nidulans. Since it spends a great part of its cell cycle in the G2period, this fungus is a special screening system for the study of mitotic recombination induced by chemical substances. Homozygotization Indexes (HI for paba and bi markers from heterozygous B211//A837 diploid strain were determined for the evaluation of the recombinagenic effect of cremophor EL. It has been shown that cremophor EL induces increase in mitotic crossing-over events at nontoxic concentrations (0.05 and 0.075% v/v.Cremofor EL (CEL é um solubilizante e emulsificante amplamente utilizado nas indústrias farmacêuticas e de gêneros alimentícios. É o principal veículo empregado nas formulações clínicas do antineoplásico paclitaxel. Considerando-se que a recombinação mitótica desempenha importante função no processo de carcinogênese, o estudo de substâncias químicas com potencial recombinagênico assume importância crucial, no sentido de se detectar aquelas que eventualmente possam atuar como promotoras de neoplasias. A genotoxicidade do cremofor EL foi estudada no presente trabalho, utilizando-se uma linhagem diplóide uvsH//uvsH de Aspergillus nidulans. Neste fungo as células vegetativas comumente repousam no período G2 do ciclo celular, facilitando a ocorrência da recombinação mitótica. O efeito recombinagênico do CEL foi avaliado através da determinação dos Índices de Homozigotização para os marcadores nutricionais paba e bi do diplóide heterozigoto B211//A837. Os

  19. Chemical and enzymatic interactions of Direct Black 38 and Direct Brown 1 on release of carcinogenic amines.

    Science.gov (United States)

    Gnanamani, A; Bhaskar, M; Ganga, Radhakrishnan; Sekaran, G; Sadulla, S

    2004-09-01

    Release of amine products from azo compounds is of considerable interest, since most of the metabolized amine products have toxic and carcinogenic characters. Moreover, most of the azo dyes are extensively used as coloring agents in inks, textiles, leathers, food and pharmaceutical industries. The present study emphasis on the quantification and comparison of amines released from water soluble dyes by (i) extra cellular protein (ECP) of Streptomyces sp. SS07 and by (ii) chemical methods. It has been observed that both the methods release considerable quantities of similar type of amine products. Release of amine compounds by ECP and chemical reduction in acid and alkaline sweat medium from a leather garment sample was also assessed. ECP (0.7852 mg protein/mg of ECP) releases benzidine and 4-amino biphenyl from Direct Black 38 and Direct Brown 1 as stable products at pH 9.2 and at 37 degrees C for a contact period of 24 h. On comparison with chemical reduction, it was observed that about 5-20% increase in the release of amine products by ECP was observed. However, more than 60% of amine products were released by chemical method from leather garment samples than direct treatment with ECP.

  20. Comparative effect of irradiation and metabolization of some chemical pollutants in animals based upon mutagenic/carcinogenic activity

    International Nuclear Information System (INIS)

    Polycyclic aromatic hydrocarbons have long been implicated as mutagens and carcinogens. The compounds selected for this study, 3,4-benzo(a)pyrene (BP) and 3-methylcholanterene (MC), were considered the most representative substances of this chemical group. Of the tested metabolites of the first, only 1,2 and 9-hydroxy-BP and diasteromers diolepoxi (7,8,9,10-cis and trans) proved mutagens. BP and MC in mammalian cells produced DNA lesions in the form of single-strand breaks and inhibition of semiconservative synthesis. They did not inhibit rejoining of DNA single-strand breaks induced by ionizing radiation. BP and MC are both mutagens only after metabolic activation, as shown in host-mediated assay and by in-vitro test. In order to establish an equivalence, the effect of three chemicals were investigated: an alkylating agent, BP and MC, the latter requiring metabolic activation. Under the given experimental conditions, 1 rad appeared as equivalent to 55 ng of IOB-82 (a cytostatic), 115 ng of BP and 178 ng of MC. This concept could prove of great importance for evaluating the risks arising from chemical and physical pollutants in man's environment

  1. Color Managing for Papers Containing Optical Brightening Agents

    Science.gov (United States)

    Millward, R. Scott

    The role of a color-managed inkjet proof is to predict and simulate the visual appearance of printed color. The proof-to-print visual match works well under different viewing conditions when the input ICC profile and the output ICC profile, built from characterization datasets, do not contain optical brightening agents (OBA). OBAs influence printed color when measured for characterization and viewed. These brightening agents absorb UV wavelengths in the illuminant and fluoresce in the blue wavelengths. As more and more OBAs are used in printing paper production, the role of color proofing becomes more difficult. The difference in the amount of the UV component of the measuring and viewing light sources cause a problem where the OBA effect, as measured, may not be the same amount of OBA effect that should be proofed under the viewing illuminant. There are two objectives in this research project. The first objective is to show how printed colors, under identical printing conditions on OBA and non-OBA substrates, look different than when they are proofed using current characterization for proofing practices. Both M0 (UV-included) and M2 (UV-cut) measurement data are collected from color patches with selected tonal values and input ICC profiles created from this data are used to proof the brightened reference print. The results show that the UV-cut characterization treatment produces a very poor proof to the reference, while the UV-included proof was ranked as a fairly high match. A third commercially available software designed to improve upon the UV-included treatment, the X-Rite Optical Brightened Compensation module, was also tested and found to be a good match to the reference as well. The second objective is to propose different ways the characterization data can be adjusted for the OBAs in a reference print on brightened paper, by accounting for the influence of UV in the measurement illuminant, and the influence of UV in the viewing illuminant. By means of

  2. IR/UV and UV/UV double-resonance study of guaiacol and eugenol dimers

    Science.gov (United States)

    Longarte, Asier; Redondo, Carolina; Fernández, José A.; Castaño, Fernando

    2005-04-01

    Guaiacol (2-methoxyphenol) and eugenol (4-allyl-2-methoxyphenol) molecules are biologically active phenol derivatives with an intramolecular -OH⋯OCH3 hydrogen bond (H bond). Pulsed supersonic expansions of mixtures of either of the two molecules with He yield weakly bound homodimers as well as other higher-order complexes. A number of complementary and powerful laser spectroscopic techniques, including UV-UV and IR-UV double resonances, have been employed to interrogate the species formed in the expansion in order to get information on their structures and spectroscopic properties. The interpretation of the spectra of eugenol dimer is complex and required a previous investigation on a similar but simpler molecule both to gain insight into the possible structures and support the conclusions. Guaiacol (2-methoxyphenol) has been used for that purpose. The combination of the broad laser study combined with ab initio calculations at the Becke 3 Lee-Yang-Parr/6-31+G(d) level has provided the isomer structures, the potential-energy wells, and shed light on the inter- and intramolecular interactions involved. Guaiacol homodimer has been shown to have a single isomer whereas eugenol dimer has at least two. The comparison between the computed geometries of the dimers, their respective energies, and the vibrational normal modes permits the identification of the spectra.

  3. Salicylic acid inhibits UV- and Cis-Pt-induced human immunodeficiency virus expression

    International Nuclear Information System (INIS)

    Previous studies have shown that exposure of HeLa cells stably transfected with a human immunodeficiency virus-long terminal repeat-chloramphenicol acetyl transferase (HIV-LTR-CAT) construct to UV light-induced expression from the HIV LTR. By culturing the cells with salicylic acid we demonstrated dose-dependent repression of this induced HIV expression. Repression was evident if salicylic acid was administered 2 h before, at the same time as, or up to 6 h after exposure to the DNA-damaging agent. The kinetics were similar for UV- and for cis-Pt-induced HIV expression, and induction was dependent on the UV dose or cis-Pt concentration added to the culture. These results suggest a role for the prostaglandins or the cyclooxygenase pathway or both in HIV induction mediated by DNA-damaging agents

  4. Simultaneous cellulose conversion and hydrogen production assisted by cellulose decomposition under UV-light photocatalysis.

    Science.gov (United States)

    Zhang, Guan; Ni, Chengsheng; Huang, Xiubing; Welgamage, Aakash; Lawton, Linda A; Robertson, Peter K J; Irvine, John T S

    2016-01-28

    Photocatalytic conversion of cellulose to sugars and carbon dioxide with simultaneous production of hydrogen assisted by cellulose decomposition under UV or solar light irradiation was achieved upon immobilization of cellulose onto a TiO2 photocatalyst. This approach enables production of hydrogen from water without using valuable sacrificial agents, and provides the possibility for recovering sugars as liquid fuels.

  5. Determination of DNA adducts by combining acid-catalyzed hydrolysis and chromatographic analysis of the carcinogen-modified nucleobases.

    Science.gov (United States)

    Leung, Elvis M K; Deng, Kailin; Wong, Tin-Yan; Chan, Wan

    2016-01-01

    The commonly used method of analyzing carcinogen-induced DNA adducts involves the hydrolysis of carcinogen-modified DNA samples by using a mixture of enzymes, followed by (32)P-postlabeling or liquid chromatography (LC)-based analyses of carcinogen-modified mononucleotides/nucleosides. In the present study, we report the development and application of a new approach to DNA adduct analysis by combining the H(+)/heat-catalyzed release of carcinogen-modified nucleobases and the use of LC-based methods to analyze DNA adducts. Results showed that heating the carcinogen-modified DNA samples at 70 °C for an extended period of 4 to 6 h in the presence of 0.05% HCl can efficiently induce DNA depurination, releasing the intact carcinogen-modified nucleobases for LC analyses. After optimizing the hydrolysis conditions, DNA samples with C8- and N (2) -modified 2'-deoxyguanosine, as well as N (6) -modified 2'-deoxyadenosine, were synthesized by reacting DNA with 1-nitropyrene, acetaldehyde, and aristolochic acids, respectively. These samples were then hydrolyzed, and the released nucleobase adducts were analyzed using LC-based analytical methods. Analysis results demonstrated a dose-dependent release of target DNA adducts from carcinogen-modified DNA samples, indicating that the developed H(+)/heat-catalyzed hydrolysis method was quantitative. Comparative studies with enzymatic digestion method on carcinogen-modified DNA samples revealed that the two hydrolysis methods did not yield systematically different results.

  6. High Power UV LED Industrial Curing Systems

    Energy Technology Data Exchange (ETDEWEB)

    Karlicek, Robert, F., Jr; Sargent, Robert

    2012-05-14

    UV curing is a green technology that is largely underutilized because UV radiation sources like Hg Lamps are unreliable and difficult to use. High Power UV LEDs are now efficient enough to replace Hg Lamps, and offer significantly improved performance relative to Hg Lamps. In this study, a modular, scalable high power UV LED curing system was designed and tested, performing well in industrial coating evaluations. In order to achieve mechanical form factors similar to commercial Hg Lamp systems, a new patent pending design was employed enabling high irradiance at long working distances. While high power UV LEDs are currently only available at longer UVA wavelengths, rapid progress on UVC LEDs and the development of new formulations designed specifically for use with UV LED sources will converge to drive more rapid adoption of UV curing technology. An assessment of the environmental impact of replacing Hg Lamp systems with UV LED systems was performed. Since UV curing is used in only a small portion of the industrial printing, painting and coating markets, the ease of use of UV LED systems should increase the use of UV curing technology. Even a small penetration of the significant number of industrial applications still using oven curing and drying will lead to significant reductions in energy consumption and reductions in the emission of green house gases and solvent emissions.

  7. Genotoxicity assessment of membrane concentrates of landfill leachate treated with Fenton reagent and UV-Fenton reagent using human hepatoma cell line.

    Science.gov (United States)

    Wang, Guifang; Lu, Gang; Yin, Pinghe; Zhao, Ling; Yu, Qiming Jimmy

    2016-04-15

    Membrane concentrates of landfill leachates contain organic and inorganic contaminants that could be highly toxic and carcinogenic. In this paper, the genotoxicity of membrane concentrates before and after Fenton and UV-Fenton reagent was assessed. The cytotoxicity and genotoxicity was determined by using the methods of methyltetrazolium (MTT), cytokinesis-block micronucleus (CBMN) and comet assay in human hepatoma cells. MTT assay showed a cytotoxicity of 75% after 24h of exposure to the highest tested concentration of untreated concentrates, and no cytotoxocity for UV-Fenton and Fenton treated concentrates. Both CBMN and comet assays showed increased levels of genotoxicity in cells exposed to untreated concentrates, compared to those occurred in cells exposed to UV-Fenton and Fenton reagent treated concentrates. There was no significant difference between negative control and UV-Fenton treated concentrates for micronucleus and comet assay parameters. UV-Fenton and Fenton treatment, especially the former, were effective methods for degradation of bisphenol A and nonylphenol in concentrates. These findings showed UV-Fenton and Fenton reaction were effective methods for treatment of such complex concentrates, UV-Fenton reagent provided toxicological safety of the treated effluent, and the genotoxicity assays were found to be feasible tools for assessment of toxicity risks of complex concentrates. PMID:26780702

  8. Land management of bracken needs to account for bracken carcinogens - a case study from Britain

    DEFF Research Database (Denmark)

    Rasmussen, Lars Holm; Donnelly, Eric; Strobel, Bjarne W.;

    2015-01-01

    Bracken ferns are some of the most widespread ferns in the World causing immense problems for land managers, foresters and rangers. Bracken is suspected of causing cancer in Humans due to its content of the carcinogen ptaquiloside. Ingestion of bracken, or food and drinking water contaminated...

  9. Human cytochrome P450 enzyme specificity for bioactivation of safrole to the proximate carcinogen 1'-hydroxysafrole

    NARCIS (Netherlands)

    Jeurissen, S.M.F.; Bogaards, J.J.P.; Awad, H.M.; Boersma, M.G.; Brand, W.; Fiamegos, Y.C.; Beek, van T.A.; Alink, G.M.; Sudhölter, E.J.R.; Cnubben, N.H.P.; Rietjens, I.M.C.M.

    2004-01-01

    In the present study, the cytochrome P450 mediated bioactivation of safrole to its proximate carcinogenic metabolite, 1'-hydroxysafrole, has been investigated for the purpose of identifying the human P450 enzymes involved. The 1'-hydroxylation of safrole was characterized in a variety of in vitro te

  10. Levels of Genotoxic and Carcinogenic Compounds in Plant food Supplements and Associated Risk Assessment

    NARCIS (Netherlands)

    Berg, van den S.J.P.L.; Restani, P.; Boersma, M.G.; Delmulle, L.; Rietjens, I.

    2011-01-01

    The present study describes the selection, analysis and risk assessment of genotoxic and carcinogenic compounds of botanicals and botanical preparations which can be found in plant food supplements (PFS). First an inventory was made of botanical compounds that are of possible concern for human healt

  11. 76 FR 71346 - Public Meeting and Request for Information: Carcinogen and Recommended Exposure Limit (REL...

    Science.gov (United States)

    2011-11-17

    ... carcinogen policy and the REL policy. NIOSH has also created a new NIOSH Cancer and REL Policy Web Topic Page....cdc.gov/niosh/enews/enewsV8N12.html and on the NIOSH Cancer and REL Policy Web Topic Page . II... comments submitted will be available within 30 days of the closing date on the NIOSH Web page at...

  12. Evaluation of an information campaign about working safely with carcinogenic substances

    NARCIS (Netherlands)

    Moonen, I.P.P.; Rijt, G.A.J. van der; Koppen, K.F.C.J. van; Gulden, J.W.J. van der

    1995-01-01

    An information campaign, organised in the Netherlands to foster safer working conditions for those who find themselves exposed to carcinogenic substances, has been evaluated. Posters, leaflets, and booklets had been distributed to those who are liable to run a risk while at work, managers as well as

  13. Occurrence of the carcinogenic Bracken constituent ptaquiloside in fronds, topsoils and organic soil layers in Denmark

    DEFF Research Database (Denmark)

    Rasmussen, L.H.; Kroghsbo, S.; Frisvad, Jens Christian;

    2003-01-01

    Bracken (Pteridium aquilinum (L.) Kuhn) is a common fern found on all continents except Antarctica. It is under suspicion of causing cancer among people who utilizes it as food. The main carcinogenic compound is thought to be the water-soluble compound ptaquiloside. Ptaquiloside-uptake may occur...

  14. 17. Exposure and Metabolism of Heterocyclic Amine Food Mutagens/Carcinogens in Humans

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@Carcinogens produced from overcooked foods are extremely mutagenic in numerous in vitro and in vivo test systems. One of these mutagens, 2-amino-1-methyl-6-phenylimidazo [4,5-b] pyridine (PhIP) induces breast, colon and prostate tumors in rats and has been implicated in dietary epidemiology studies for raising the risk of

  15. Myricetin stimulates the absorption of the pro-carcinogen PhIP

    NARCIS (Netherlands)

    Schutte, M.E.; Sandt, van de J.J.M.; Alink, G.M.; Groten, J.P.; Rietjens, I.M.C.M.

    2006-01-01

    The effect of the flavonoid myricetin on the transport of the pro-carcinogen 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) through differentiated Caco-2 monolayers, a model for the intestinal epithelium, is described. Myricetin causes an increase of the transport of PhIP from the apical to

  16. [Using the evaluation of carcinogenic risk in the mining and metallurgical enterprises of the Arctic].

    Science.gov (United States)

    Serebriakov, P V

    2012-01-01

    The aim of this study--hygienic assessment of the contribution of factors of working environment) in the formation of carcinogenic risk to the mining and metallurgical enterprises of the Far North, the establishment of the structural features of cancer pathology among workers of these enterprises, quantitative evaluation of individual professional cancer risk in different nosological forms and morphological variants of malignant neoplasms.

  17. 78 FR 16681 - International Conference on Harmonisation; Proposed Change to Rodent Carcinogenicity Testing of...

    Science.gov (United States)

    2013-03-18

    ....-based company started a project with 60 company-owned and marketed compounds (Ref. 3) with the outcome... involving 13 companies. A. Carcinogenicity Studies In 2011, PhRMA published a database analysis (Ref. 4..., reduce use of animals in accordance with the 3Rs (reduce/refine/replace) principle, reduce the use...

  18. Carcinogens, Teratogens and Mutagens: Their Impact on Occupational Health, Particularly for Women in Veterinary Medicine.

    Science.gov (United States)

    Milligan, J. E.; And Others

    1983-01-01

    Pregnant women, especially those working in veterinary medicine, face occupational health/disease risks from mutagens, teratogens, and carcinogens. These hazards can be placed into three categories: physical, chemical, and biological. Each of these hazards is discussed with examples. (Author/JN)

  19. Repair of DNA treated with lambda-irradiation and chemical carcinogens. Progress report, 1984-1985

    International Nuclear Information System (INIS)

    Research progress is reported in the following areas: (1) DNA repair in HeLa cells; (2) a search for human transposable elements; (3) the effect of radiation and carcinogens on the activation of LTR sequences; and (4) studies on oncogenes of central nervous system tumors

  20. Developmental transcriptomic features of the carcinogenic liver fluke, Clonorchis sinensis.

    Directory of Open Access Journals (Sweden)

    Won Gi Yoo

    2011-06-01

    Full Text Available Clonorchis sinensis is the causative agent of the life-threatening disease endemic to China, Korea, and Vietnam. It is estimated that about 15 million people are infected with this fluke. C. sinensis provokes inflammation, epithelial hyperplasia, and periductal fibrosis in bile ducts, and may cause cholangiocarcinoma in chronically infected individuals. Accumulation of a large amount of biological information about the adult stage of this liver fluke in recent years has advanced our understanding of the pathological interplay between this parasite and its hosts. However, no developmental gene expression profiles of C. sinensis have been published. In this study, we generated gene expression profiles of three developmental stages of C. sinensis by analyzing expressed sequence tags (ESTs. Complementary DNA libraries were constructed from the adult, metacercaria, and egg developmental stages of C. sinensis. A total of 52,745 ESTs were generated and assembled into 12,830 C. sinensis assembled EST sequences, and then these assemblies were further categorized into groups according to biological functions and developmental stages. Most of the genes that were differentially expressed in the different stages were consistent with the biological and physical features of the particular developmental stage; high energy metabolism, motility and reproduction genes were differentially expressed in adults, minimal metabolism and final host adaptation genes were differentially expressed in metacercariae, and embryonic genes were differentially expressed in eggs. The higher expression of glucose transporters, proteases, and antioxidant enzymes in the adults accounts for active uptake of nutrients and defense against host immune attacks. The types of ion channels present in C. sinensis are consistent with its parasitic nature and phylogenetic placement in the tree of life. We anticipate that the transcriptomic information on essential regulators of development

  1. Transparent and UV-shielding ZnO@PMMA nanocomposite films

    Science.gov (United States)

    Zhang, Yewei; Zhuang, Shendong; Xu, Xiaoyong; Hu, Jingguo

    2013-12-01

    We fabricated successfully the visible light (VL)-traversing and ultraviolet (UV)-shielding zinc oxide quantum dots (ZnO QDs)-poly(methyl methacrylate) (PMMA) nanocomposite films by incorporating suitable UV-absorbing ZnO QDs into a transparent PMMA matrix. The ZnO QDs of about 5 nm were first synthesized via a sol-gel route. Then the 3-(trimethoxysilyl)propylmethacrylate (TPM) as a coupling agent is bound to the surface of ZnO QDs, inhibiting the agglomeration of QDs and promoting the compatibility between ZnO QDs and PMMA matrix. Such the transparent ZnO@PMMA nanocomposite films exhibit the prominent UV-absorbing capability and the high optical transparency in the visible-wavelength region, thus have direct practical applications such as UV-shielding windows and glasses.

  2. Carcinogen-induced DNA repair in nucleotide-permeable Escherichia coli cells

    International Nuclear Information System (INIS)

    Upon exposure to the carcinogens N-acetoxy-N-2-acetylaminofluorene and 7-bromomethyl-benz[a]anthracene, which bind covalently to DNA, ether-permeabilized (nucleotide-permeable) Escherichia coli wild-type cells responded with DNA excision repair. This repair was missing in mutants carrying defects in genes uvrA, uvrB and uvrC, whereas it was present in uvrD and several rec mutants. Enzymic activities involved were identified by measuring repair polymerization and size reduction of denatured DNA. An easily measurable effect in E. coli wild-type cells was carcinogen-induced repair polymerization. When initiated by N-acetoxy-N-2-acetylaminofluorene or 7-bromomethyl-benz[a]anthracene, it depended upton an ATP-requiring step; CTP, GTP or UTP did not substitute for ATP. DNA repair synthesis was inhibited by p-chloromercuribenzoate and quinacrine. In uvrA, uvrB and uvrC mutants no carcinogen-stimulated DNA synthesis could be detected, indicating that steps involved in pyrimidine dimer excision are also involved in chemorepair. In recA, recB and recC mutant cells, repair synthesis was stimulated by the carcinogens to a normal extent. This evidence excludes the ATP-dependent recB,C deoxyribonuclease and recA gene products as playing an important role in carcinogen-induced excision repair. polA1 cells showed drastically reduced levels of repair polymerization, indicating that DNA polymerase I is the main polymerizing enzyme. As determined by DNA size reduction in alkaline sucrose gradients, the arylalkylating carcinogens caused endonucleolytic cleavage of endogenous DNA in wild-type cells. This incision step was most effectively performed in the presence of ATP; UTP, CTP and GTP were only slightly effective. Incision was inhibited by p-chloromercuribenzoate and quinacrine. When exposed to the arylalkylating carcinogens, uvrA, uvrB and uvrC mutant cells did not perform the incision step in the presence of ATP, suggesting the involvement of the respective gene products in the

  3. XI UV Laser Trigger System

    Energy Technology Data Exchange (ETDEWEB)

    Brickeen, B.K.; Morelli, G.L.; Paiva, R.A.; Powell, C.A.; Sundvold, P.D.

    1999-01-26

    The X1 accelerator project at Sandia National Laboratory/New Mexico utilizes SF6 insulated, multi-stage, UV laser triggered gas switches. A 265 nm UV laser system was designed and built to generate eight simultaneous output pulses of 10 mJ each with a 13 nsec pulse width. A 1061 nm solid-state Nd:Cr:GSGG laser was frequency quadrupled using a two-stage doubling process. The 1061 nm fundamental laser energy was frequency doubled with a KTP crystal to 530 nm, achieving 65% conversion efficiency. The 530 nm output was frequency doubled with KD*P crystal to 265 nm, achieving conversion efficiency of 31%. The 265 nm beam pulse was split into eight parallel channels with a system of partially reflecting mirrors. Low timing jitter and stable energy output were achieved. The entire optical system was packaged into a rugged, o-ring sealed, aluminum structure 10''x19''x2.75''. The size of the electronics was 12''x8''x8''. Subsequent accelerator system requirements dictated a redesign of the triggering system for an output beam with less angular divergence. An unstable, crossed porro prism resonator was designed and incorporated into the system. The beam divergence of the redesigned system was successfully decreased to 0.97 mrad in the UV. The resulting frequency doubling efficiencies were 55% to 530 nm and 25% to 265 nm. The optical output remained at 10 mJ in each channel with an 11 nsec pulse width.

  4. The carcinogenicity of certain derivatives of p-dimethylaminozobenz in the rat.

    Science.gov (United States)

    MILLER, J A; MILLER, E C

    1948-02-01

    1. Eighteen known or possible metabolites of the hepatic carcinogen 4- (or p-) dimethylaminoazobenzene were tested for carcinogenic activity in the rat. Of these compounds only 4-monomethylaminoazobenzene, a known metabolite, proved to be active. Eight compounds, which appear to be metabolites of the dye, were inactive; these included 4-aminoazobenzene, 4'-hydroxy-4-monomethylaminoazobenzene, 4'-hydroxy-4-aminoazobenzene, N-methyl-p-phenylenediamine, p-phenylenediamine, aniline, p-aminophenol, and o-aminophenol. Nine compounds which may possibly be metabolites also were inactive; these compounds were 4'-hydroxy-, 3'-hydroxy-, and 2'-hydroxy-4-dimethylaminoazobenzene, 4-formylaminoazobenzene, 4-hydroxyazobenzene, 2, 4'-diamino-5-dimethylaminodiphenyl, 3-dimethylaminocarbazole, N,N-dimethyl-p-phenylenediamine, and p-hydroquinone. A mixture of 9 known and possible metabolites was also found to be inactive. These data indicate that the primary carcinogen operative in tumor formation by 4-dimethylaminoazobenzene is probably an azo dye closely related to the parent carcinogen. This conclusion is supported by recent work from this laboratory which indicates that the primary carcinogen consists of either or both of the protein-bound dyes found in the liver, i.e. 4-monomethylaminoazobenzene and an unidentified polar aminoazo dye, and that the formation of bound dye constitutes one of the first steps in this carcinogenic process. 2. The carcinogenic activities of 19 other compounds related to 4-dimethyl-aminoazobenzene were tested to obtain more information on the structural features needed for a 4-aminoazo dye to possess strong activity in the rat. 3'-Methyl-4-monomethylaminoazobenzene and the corresponding dimethylamino derivative were nearly twice as active and 4-ethylmethylaminoazobenzene had the same activity as 4-dimethylaminoazobenzene. As tested 3'-nitro- and 3'-chloro-4-dimethylaminoazobenzene both had about the same activity as 4-dimethylaminoazobenzene; however

  5. UV-induced Melanin Chemiexcitation: A New Mode of Melanoma Pathogenesis.

    Science.gov (United States)

    Brash, Douglas E

    2016-06-01

    Mutations in sunlight-induced melanoma arise from cyclobutane pyrimidine dimers (CPDs), DNA photoproducts usually created picoseconds after an ultraviolet (UV) photon is absorbed at thymine or cytosine. Surprisingly, we found that, in melanocytes, CPDs were generated for hours after UVA or UVB exposure. These "dark CPDs" constituted the majority of CPDs in cultured human and murine melanocytes and in mouse skin, and they were most prominent in skin containing pheomelanin, the melanin responsible for blonde and red hair. The mechanism was also a surprise. Dark cyclobutane pyrimidine dimers (CPDs) arise when ultraviolet (UV)-induced superoxide and nitric oxide combine to form peroxynitrite, one of the few biological molecules capable of exciting an electron. This process, termed "chemiexcitation," is the source of bioluminescence in lower organisms. Excitation occurred in fragments of melanin, creating a quantum triplet state that had the energy of a UV photon but which induced CPDs by radiationless energy transfer to DNA. UVA and peroxynitrite also solubilized melanin and permeabilized the nuclear membrane, allowing melanin to enter. Melanin is evidently carcinogenic as well as protective. Chemiexcitation may also trigger pathogenesis in internal tissues because the same chemistry should arise wherever superoxide and nitric oxide arise near cells that contain melanin. PMID:26951162

  6. Ochratoxin A induces rat renal carcinogenicity with limited induction of oxidative stress responses

    Energy Technology Data Exchange (ETDEWEB)

    Qi, Xiaozhe; Yu, Tao; Zhu, Liye; Gao, Jing [College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083 (China); He, Xiaoyun; Huang, Kunlun; Luo, Yunbo [College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083 (China); The Supervision, Inspection and Testing Center of Genetically Modified Organisms, Ministry of Agriculture, Beijing 100083 (China); Xu, Wentao, E-mail: xuwentao@cau.edu.cn [College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083 (China); The Supervision, Inspection and Testing Center of Genetically Modified Organisms, Ministry of Agriculture, Beijing 100083 (China)

    2014-11-01

    Ochratoxin A (OTA) has displayed nephrotoxicity and renal carcinogenicity in mammals, however, no clear mechanisms have been identified detailing the relationship between oxidative stress and these toxicities. This study was performed to clarify the relationship between oxidative stress and the renal carcinogenicity induced by OTA. Rats were treated with 70 or 210 μg/kg b.w. OTA for 4 or 13 weeks. In the rats administrated with OTA for 13 weeks, the kidney was damaged seriously. Cytoplasmic vacuolization was observed in the outer stripe of the outer medulla. Karyomegaly was prominent in the tubular epithelium. Kidney injury molecule-1 (Kim-1) was detected in the outer stripe of the outer medulla in both low- and high-dose groups. OTA increased the mRNA levels of clusterin in rat kidneys. Interestingly, OTA did not significantly alter the oxidative stress level in rat liver and kidney. Yet, some indications related to proliferation and carcinogenicity were observed. A dose-related increase in proliferating cell nuclear antigen (PCNA) was observed at 4 weeks in both liver and kidney, but at 13 weeks, only in the kidney. OTA down-regulated reactive oxygen species (ROS) and up-regulated vimentin and lipocalin 2 in rat kidney at 13 weeks. The p53 gene was decreased in both liver and kidney at 13 weeks. These results suggest that OTA caused apparent kidney damage within 13 weeks but exerted limited effect on oxidative stress parameters. It implies that cell proliferation is the proposed mode of action for OTA-induced renal carcinogenicity. - Highlights: • We studied OTA toxicities in both the rat liver and kidney for 13 weeks. • OTA exerts limited effects on oxidative stress in the rat liver and kidney. • OTA induced renal carcinogenicity resulting from cell proliferation.

  7. UV dosimeter based on polyamide woven fabric and nitro blue tetrazolium chloride as an active compound

    Energy Technology Data Exchange (ETDEWEB)

    Kozicki, Marek, E-mail: mkozicki@mitr.p.lodz.pl [Institute of Architecture of Textiles, Technical University of Lodz, Zeromskiego 116, 90-924 Lodz (Poland); European Centre of Bio- and Nano-Technology (ECBNT), Technical University of Lodz, Zeromskiego 116, 90-924 Lodz (Poland); Sasiadek, Elzbieta [Institute of Architecture of Textiles, Technical University of Lodz, Zeromskiego 116, 90-924 Lodz (Poland); European Centre of Bio- and Nano-Technology (ECBNT), Technical University of Lodz, Zeromskiego 116, 90-924 Lodz (Poland)

    2011-10-15

    This paper reports on the preparation and features of a UV light dosimeter composed of nitro blue tetrazolium chloride (NBT) and polyamide woven fabric. This textile dosimeter is based on the conversion reaction of NBT into formazan, which was initially examined in aerated aqueous solutions through steady state UV irradiation. Irradiated solutions change their colour as a consequence of the formation of polydisperse NBT formazan particles. This was analysed in relation to the absorbed dose of UV light through UV-VIS spectrophotometry and dynamic laser light scattering measurements. When NBT substrate molecules are embedded in polyamide textile, UV irradiation leads to similar effects as in solution. However, the tinge intensity changes at much lower absorbed doses. The dependence of the tinge intensity on the absorbed dose was followed by measurements of the remission of light from the NBT-polyamide samples. Consequently, the calibration parameters were calculated such as the dose sensitivity, dose range, and quasi-linear dose range. An improvement of the NBT-polyamide samples by application of a colour levelling agent and improvement of their resistance to humidity is presented. Finally, the samples were used for estimation of absorbed UV energy distribution showing their capability as new dosimeters for in-plane high resolution radiation dose measurements. - Highlights: > Preparation of a textile dosimeter with nitro blue tetrazolium chloride is shown. > The dosimeter responds to UV light by a colour change. > 2D radiation dose measurements are possible. > PC scanners can be employed for measurements of the dosimeter.

  8. UV dosimeter based on polyamide woven fabric and nitro blue tetrazolium chloride as an active compound

    International Nuclear Information System (INIS)

    This paper reports on the preparation and features of a UV light dosimeter composed of nitro blue tetrazolium chloride (NBT) and polyamide woven fabric. This textile dosimeter is based on the conversion reaction of NBT into formazan, which was initially examined in aerated aqueous solutions through steady state UV irradiation. Irradiated solutions change their colour as a consequence of the formation of polydisperse NBT formazan particles. This was analysed in relation to the absorbed dose of UV light through UV-VIS spectrophotometry and dynamic laser light scattering measurements. When NBT substrate molecules are embedded in polyamide textile, UV irradiation leads to similar effects as in solution. However, the tinge intensity changes at much lower absorbed doses. The dependence of the tinge intensity on the absorbed dose was followed by measurements of the remission of light from the NBT-polyamide samples. Consequently, the calibration parameters were calculated such as the dose sensitivity, dose range, and quasi-linear dose range. An improvement of the NBT-polyamide samples by application of a colour levelling agent and improvement of their resistance to humidity is presented. Finally, the samples were used for estimation of absorbed UV energy distribution showing their capability as new dosimeters for in-plane high resolution radiation dose measurements. - Highlights: → Preparation of a textile dosimeter with nitro blue tetrazolium chloride is shown. → The dosimeter responds to UV light by a colour change. → 2D radiation dose measurements are possible. → PC scanners can be employed for measurements of the dosimeter.

  9. The Skin Microbiome: Is It Affected by UV-induced Immune Suppression?

    Science.gov (United States)

    Patra, VijayKumar; Byrne, Scott N; Wolf, Peter

    2016-01-01

    Human skin apart from functioning as a physical barricade to stop the entry of pathogens, also hosts innumerable commensal organisms. The skin cells and the immune system constantly interact with microbes, to maintain cutaneous homeostasis, despite the challenges offered by various environmental factors. A major environmental factor affecting the skin is ultraviolet radiation (UV-R) from sunlight. UV-R is well known to modulate the immune system, which can be both beneficial and deleterious. By targeting the cells and molecules within skin, UV-R can trigger the production and release of antimicrobial peptides, affect the innate immune system and ultimately suppress the adaptive cellular immune response. This can contribute to skin carcinogenesis and the promotion of infectious agents such as herpes simplex virus and possibly others. On the other hand, a UV-established immunosuppressive environment may protect against the induction of immunologically mediated skin diseases including some of photodermatoses such as polymorphic light eruption. In this article, we share our perspective about the possibility that UV-induced immune suppression may alter the landscape of the skin's microbiome and its components. Alternatively, or in concert with this, direct UV-induced DNA and membrane damage to the microbiome may result in pathogen associated molecular patterns (PAMPs) that interfere with UV-induced immune suppression. PMID:27559331

  10. The Skin Microbiome: Is It Affected by UV-induced Immune Suppression?

    Science.gov (United States)

    Patra, VijayKumar; Byrne, Scott N.; Wolf, Peter

    2016-01-01

    Human skin apart from functioning as a physical barricade to stop the entry of pathogens, also hosts innumerable commensal organisms. The skin cells and the immune system constantly interact with microbes, to maintain cutaneous homeostasis, despite the challenges offered by various environmental factors. A major environmental factor affecting the skin is ultraviolet radiation (UV-R) from sunlight. UV-R is well known to modulate the immune system, which can be both beneficial and deleterious. By targeting the cells and molecules within skin, UV-R can trigger the production and release of antimicrobial peptides, affect the innate immune system and ultimately suppress the adaptive cellular immune response. This can contribute to skin carcinogenesis and the promotion of infectious agents such as herpes simplex virus and possibly others. On the other hand, a UV-established immunosuppressive environment may protect against the induction of immunologically mediated skin diseases including some of photodermatoses such as polymorphic light eruption. In this article, we share our perspective about the possibility that UV-induced immune suppression may alter the landscape of the skin’s microbiome and its components. Alternatively, or in concert with this, direct UV-induced DNA and membrane damage to the microbiome may result in pathogen associated molecular patterns (PAMPs) that interfere with UV-induced immune suppression. PMID:27559331

  11. The skin microbiome: Is it affected by UV-induced immune suppression?

    Directory of Open Access Journals (Sweden)

    Vijaykumar Patra

    2016-08-01

    Full Text Available Human skin apart from functioning as a physical barricade to stop the entry of pathogens, also hosts innumerable commensal organisms. The skin cells and the immune system constantly interact with microbes, to maintain cutaneous homeostasis, despite the challenges offered by various environmental factors. A major environmental factor affecting the skin is ultraviolet radiation UV-R from sunlight. UV-R is well known to modulate the immune system, which can be both beneficial and deleterious. By targeting the cells and molecules within skin, UV-R can trigger the production and release of antimicrobial peptides (AMPs, affect the innate immune system and ultimately suppress the adaptive cellular immune response. This can contribute to skin carcinogenesis and the promotion of infectious agents such as herpes simplex virus and possibly others. On the other hand, a UV-established immunosuppressive environment may protect against the induction of immunologically mediated skin diseases including some of photodermatoses such as polymorphic light eruption. In this article, we share our perspective about the possibility that UV-induced immune suppression may alter the landscape of the skin's microbiome and its components. Alternatively, or in concert with this, direct UV-induced DNA and membrane damage to the microbiome may result in pathogen associated molecular patterns (PAMPs that interfere with UV-induced immune suppression.

  12. Temporal variation of optimal UV exposure time over Korea: risks and benefits of surface UV radiation

    Science.gov (United States)

    Lee, Y. G.; Koo, J. H.

    2015-12-01

    Solar UV radiation in a wavelength range between 280 to 400 nm has both positive and negative influences on human body. Surface UV radiation is the main natural source of vitamin D, providing the promotion of bone and musculoskeletal health and reducing the risk of a number of cancers and other medical conditions. However, overexposure to surface UV radiation is significantly related with the majority of skin cancer, in addition other negative health effects such as sunburn, skin aging, and some forms of eye cataracts. Therefore, it is important to estimate the optimal UV exposure time, representing a balance between reducing negative health effects and maximizing sufficient vitamin D production. Previous studies calculated erythemal UV and vitamin-D UV from the measured and modelled spectral irradiances, respectively, by weighting CIE Erythema and Vitamin D3 generation functions (Kazantzidis et al., 2009; Fioletov et al., 2010). In particular, McKenzie et al. (2009) suggested the algorithm to estimate vitamin-D production UV from erythemal UV (or UV index) and determined the optimum conditions of UV exposure based on skin type Ⅱ according to the Fitzpatrick (1988). Recently, there are various demands for risks and benefits of surface UV radiation on public health over Korea, thus it is necessary to estimate optimal UV exposure time suitable to skin type of East Asians. This study examined the relationship between erythemally weighted UV (UVEry) and vitamin D weighted UV (UVVitD) over Korea during 2004-2012. The temporal variations of the ratio (UVVitD/UVEry) were also analyzed and the ratio as a function of UV index was applied in estimating the optimal UV exposure time. In summer with high surface UV radiation, short exposure time leaded to sufficient vitamin D and erythema and vice versa in winter. Thus, the balancing time in winter was enough to maximize UV benefits and minimize UV risks.

  13. Report on NCI symposium: comparison of mechanisms of carcinogenesis by radiation and chemical agents. II. Cellular and animal models

    Energy Technology Data Exchange (ETDEWEB)

    Fry, R.J.M.

    1984-01-01

    The point at which the common final pathway for induction of cancer by chemical carcinogens and ionizing radiation has not been identified. Although common molecular targets are suggested by recent findings about the role of oncogenes, the mechanism by which the deposition of radiation energy and the formation of adducts or other DNA lesions induced by chemicals affects the changes in the relevant targets may be quite different. The damage to DNA that plays no part in the transformation events, but that influences the stability of the genome, and therefore, the probability of subsequent changes that influence tumorigenesis may be more readily induced by some agents than others. Similarly, the degree of cytotoxic effects that disrupt tissue integrity and increase the probability of expression of initiated cells may be dependent on the type of carcinogen. Also, evidence was presented that repair of the initial lesions could be demonstrated after exposure to low-LET radiation but not after exposure to chemical carcinogens.

  14. UV-induced cutaneous photobiology.

    Science.gov (United States)

    Beissert, S; Granstein, R D

    1996-12-01

    Ultraviolet radiation (UVR) present in sunlight is a major environmental factor capable of affecting human health and well being. The organ primarily affected by UVR is the skin, which is composed of a variety of different cell types. Here, UVR is needed for production of active vitamin D as well as producing undesirable effects such as sunburn, premature cutaneous photoaging, and promoting skin cancer development. Depending on the radiation dose, UVR influences virtually every cutaneous cell type investigated differently. Since the end of the nineteenth century, sun exposure has been known to induce skin cancer, which is now the human malignancy with the most rapidly increasing incidence. In several experimental models, mid-range UVR has been demonstrated to be the major cause of UV-induced cutaneous tumors. The stratospheric ozone layer protecting the terrestrial surface from higher quantum energy solar radiation is being damaged by industrial activities resulting in the possibility of increased UVR exposure in the future. Investigations in the field of experimental dermatology have shown that within the skin an immunosurveillance system exists that may be able to detect incipient neoplasms and to elicit a host responses against it. This article reviews the literature on studies designed to investigate the effects of UVR on cutaneous cellular components, with special focus on the immune system within the skin and the development of UV-induced cancer. PMID:8994803

  15. AgentChess : An Agent Chess Approach

    OpenAIRE

    Fransson, Henric

    2003-01-01

    The game of chess has many times been discussed and used for test purpose by science departments of Artificial Intelligence (AI). Although the technique of agent and as well multi-agent systems is quite old, the use of these offspring of AI within chess is limited. This report describes the project performed applying the use of agents to a chess program. To measure the performance of the logic has tests between the developed program main parts been performed. Further tests against a tradition...

  16. Investigation of the mechanisms by which UV irradiation activates the tyrosinase gene

    Energy Technology Data Exchange (ETDEWEB)

    Bao, Y

    2000-04-01

    within this 100-bp, totally abolished the stimulation of CAT activity in response to UV irradiation, thus suggesting a key role of this potential CRE motif in the UV response of the 100-bp promoter. Since the CRE motif binds transcription factors of CREB family, it is possible that CREB or a related protein, could be involved in UV-activation of tyrosinase gene expression. Microphthalmia (Mi), a basic helix-loop-helix (bHLH) transcription factor which binds to a CANNTG E-motif, has recently been demonstrated to be important in tyrosinase and TRP-1 gene expression. The tyrosinase, TRP-1 and TRP-2 promoters share a CATGTG E-motif within a conserved 11 bp M-box. Mi is able to transactivate the human tyrosinase and TRP-1 gene promoter through the E-motif and cAMP elevating agents led to a rapid, but transient increase in Mi mRNA and protein levels in B16 melanoma cells. To investigate the possible role of Mi in UV-induced melanogenesis, the effects of UV irradiation on gene expression and protein phosphorylation of Mi were examined. UV irradiation caused a marked reduction of Mi mRNA. This suggested that Mi was unlikely to be involved in the stimulation of the tyrosinase gene expression by UV. When using a One-hybrid System to study activation of the Mi phosphorylation, however, UV irradiation caused a small increase in GAL4-Mi-dependent luciferase activity, indicating a phosphorylation of Mi by UV. The mechanisms under these effects need to be further investigated. (author)

  17. Prediction of rodent carcinogenicity using the DEREK system for 30 chemicals currently being tested by the National Toxicology Program. The DEREK Collaborative Group.

    OpenAIRE

    Marchant, C A

    1996-01-01

    DEREK is a knowledge-based expert system for the qualitative prediction of toxicity. The DEREK system has been used to predict the carcinogenicity in rodents of the 30 chemicals in the second National Toxicology Program (NTP) carcinogenicity prediction exercise. Seven of the chemicals were predicted to be carcinogens. For 23 chemicals, there was no evidence in the DEREK knowledge base to suggest carcinogenic activity. Supplementary data from a variety of sources have been evaluated by human e...

  18. Beneficial and adverse effects of chemopreventive agents

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Byung Mu; Park, Kwang-Kyun

    2003-03-01

    The beneficial and adverse effects of some chemopreventive agents, such as Vitamins A, C, E, beta-carotene, indole-3-carbinol, capsaicin, garlic, and aloe are reviewed. Two large randomized trials with a lung cancer endpoint, the Alpha-Tocopherol, Beta-Carotene (ATBC) Prevention Study and the Beta-Carotene and Retinol Efficacy Trial (CARET), suggested that antioxidants might be harmful in smokers. However, the results of the Linxian study and of the ATBC or the CARET studies were significantly different in this respect, and therefore, the relationship between antioxidant and carcinogenesis remains open to debate. Indole-3-carbinol has cancer promoting activities in the colon, thyroid, pancreas, and liver, whereas capsaicin alters the metabolism of chemical carcinogens and may promote carcinogenesis at high doses. Organosulfur compounds and selenium from garlic have no or a little enhancing effect on cancer promotion stage. Information upon chemopreventive mechanisms that inhibit carcinogenesis is imperfect, although the causes and natures of certain human cancers are known. Therefore, definitive preventive guidelines should be carefully offered for various types of tumors, which properly consider ethnic variations, and the efficacies and the safety of chemopreventive agents.

  19. Riot Control Agents

    Science.gov (United States)

    ... a person has been exposed to riot control agents. Long-term health effects of exposure to riot control agents Prolonged ... person is removed from exposure to riot control agents, long-term health effects are unlikely to occur. How you can ...

  20. Reasoning about emotional agents

    NARCIS (Netherlands)

    Meyer, J.-J.

    2008-01-01

    In this paper we discuss the role of emotions in artificial agent design, and the use of logic in reasoning about the emotional or affective states an agent can reside in. We do so by extending the KARO framework for reasoning about rational agents appropriately. In particular we formalize in this f

  1. Study of molecular mechanisms of UV-induced aggregation of crystallins and possibility of maintaining eye lens transparency

    Science.gov (United States)

    Soustov, L. V.; Chelnokov, E. V.; Bityurin, N. M.; Kiselev, A. L.; Nemov, V. V.; Sergeev, Yu. V.; Ostrovsky, M. A.

    2006-03-01

    The effect of D-pantethine and L-carnosine on the rate of UV-induced (XeC1 laser λ = 308 nm) aggregation of a mixture of βL-crystallin and α-crystallin is studied. We also demonstrate that the suggested by us combination of short-chain peptides shows better protective properties with respect to UV-induced aggregation than known anti-cataract agents.

  2. Agents modeling agents in information economies

    Energy Technology Data Exchange (ETDEWEB)

    Vidal, J.M.; Durfee, E.H. [Univ. of Michigan, Ann Arbor, MI (United States)

    1996-12-31

    Our goal is to design and build agents that act intelligently when placed in an agent-based information economy, where agents buy and sell services (e.g. thesaurus, search, task planning services, etc.). The economy we are working in is the University of Michigan Digital Library (UMDL), a large scale multidisciplinary effort to build an infrastructure for the delivery of library services. In contrast with a typical economy, an information economy deals in goods and services that are often derived from unique sources (authors, analysts, etc.), so that many goods and services are not interchangeable. Also, the cost of replicating and transporting goods is usually negligible, and the quality of goods and services is difficult to measure objectively: even two sources with essentially the same information might appeal to different audiences. Thus, each agent has its own assessment of the quality of goods and services delivered.

  3. UV-Induced Cell Death in Plants

    Directory of Open Access Journals (Sweden)

    Chang Ho Kang

    2013-01-01

    Full Text Available Plants are photosynthetic organisms that depend on sunlight for energy. Plants respond to light through different photoreceptors and show photomorphogenic development. Apart from Photosynthetically Active Radiation (PAR; 400–700 nm, plants are exposed to UV light, which is comprised of UV-C (below 280 nm, UV-B (280–320 nm and UV-A (320–390 nm. The atmospheric ozone layer protects UV-C radiation from reaching earth while the UVR8 protein acts as a receptor for UV-B radiation. Low levels of UV-B exposure initiate signaling through UVR8 and induce secondary metabolite genes involved in protection against UV while higher dosages are very detrimental to plants. It has also been reported that genes involved in MAPK cascade help the plant in providing tolerance against UV radiation. The important targets of UV radiation in plant cells are DNA, lipids and proteins and also vital processes such as photosynthesis. Recent studies showed that, in response to UV radiation, mitochondria and chloroplasts produce a reactive oxygen species (ROS. Arabidopsis metacaspase-8 (AtMC8 is induced in response to oxidative stress caused by ROS, which acts downstream of the radical induced cell death (AtRCD1 gene making plants vulnerable to cell death. The studies on salicylic and jasmonic acid signaling mutants revealed that SA and JA regulate the ROS level and antagonize ROS mediated cell death. Recently, molecular studies have revealed genes involved in response to UV exposure, with respect to programmed cell death (PCD.

  4. Homeostatic response under carcinogen withdrawal, heme oxygenase 1 expression and cell cycle association

    International Nuclear Information System (INIS)

    Chronic injury deregulates cellular homeostasis and induces a number of alterations leading to disruption of cellular processes such as cell cycle checkpoints and apoptosis, driving to carcinogenesis. The stress protein heme oxygenase-1 (HO-1) catalyzes heme degradation producing biliverdin, iron and CO. Induction of HO-1 has been suggested to be essential for a controlled cell growth. The aim of this work was to analyze the in vivo homeostatic response (HR) triggered by the withdrawal of a potent carcinogen, p-dimethylaminoazobenzene (DAB), after preneoplastic lesions were observed. We analyzed HO-1 cellular localization and the expression of HO-1, Bcl-2 and cell cycle related proteins under these conditions comparing them to hepatocellular carcinoma (HC). The intoxication protocol was designed based on previous studies demonstrating that preneoplastic lesions were evident after 89 days of chemical carcinogen administration. Male CF1 mice (n = 18) were used. HR group received DAB (0.5 % w/w) in the diet for 78 days followed by 11 days of carcinogen deprivation. The HC group received the carcinogen and control animals the standard diet during 89 days. The expression of cell cycle related proteins, of Bcl-2 and of HO-1 were analyzed by western blot. The cellular localization and expression of HO-1 were detected by immnunohistochemistry. Increased expression of cyclin E/CDK2 was observed in HR, thus implicating cyclin E/CDK2 in the liver regenerative process. p21cip1/waf1 and Bcl-2 induction in HC was restituted to basal levels in HR. A similar response profile was found for HO-1 expression levels, showing a lower oxidative status in the carcinogen-deprived liver. The immunohistochemical studies revealed the presence of macrophages surrounding foci of necrosis and nodular lesions in HR indicative of an inflammatory response. Furthermore, regenerative cells displayed changes in type, size and intensity of HO-1 immunostaining. These results demonstrate that the

  5. Homeostatic response under carcinogen withdrawal, heme oxygenase 1 expression and cell cycle association

    Directory of Open Access Journals (Sweden)

    Batlle Alcira

    2006-12-01

    Full Text Available Abstract Background Chronic injury deregulates cellular homeostasis and induces a number of alterations leading to disruption of cellular processes such as cell cycle checkpoints and apoptosis, driving to carcinogenesis. The stress protein heme oxygenase-1 (HO-1 catalyzes heme degradation producing biliverdin, iron and CO. Induction of HO-1 has been suggested to be essential for a controlled cell growth. The aim of this work was to analyze the in vivo homeostatic response (HR triggered by the withdrawal of a potent carcinogen, p-dimethylaminoazobenzene (DAB, after preneoplastic lesions were observed. We analyzed HO-1 cellular localization and the expression of HO-1, Bcl-2 and cell cycle related proteins under these conditions comparing them to hepatocellular carcinoma (HC. Methods The intoxication protocol was designed based on previous studies demonstrating that preneoplastic lesions were evident after 89 days of chemical carcinogen administration. Male CF1 mice (n = 18 were used. HR group received DAB (0.5 % w/w in the diet for 78 days followed by 11 days of carcinogen deprivation. The HC group received the carcinogen and control animals the standard diet during 89 days. The expression of cell cycle related proteins, of Bcl-2 and of HO-1 were analyzed by western blot. The cellular localization and expression of HO-1 were detected by immnunohistochemistry. Results Increased expression of cyclin E/CDK2 was observed in HR, thus implicating cyclin E/CDK2 in the liver regenerative process. p21cip1/waf1 and Bcl-2 induction in HC was restituted to basal levels in HR. A similar response profile was found for HO-1 expression levels, showing a lower oxidative status in the carcinogen-deprived liver. The immunohistochemical studies revealed the presence of macrophages surrounding foci of necrosis and nodular lesions in HR indicative of an inflammatory response. Furthermore, regenerative cells displayed changes in type, size and intensity of HO-1

  6. Photoluminescence of trypsin after UV-irradiation

    International Nuclear Information System (INIS)

    For study purposes of the primary effects of UV light the photoluminescence of trypsin was investigated before and after UV irradiation (lambda = 254 nm). The results were compared with the corresponding relations at equimolar mixtures of the constituent amino acids. The increase of the absorption in the region between 230 nm and 400 nm at UV irradiation of trypsin in aqueous solution is primarily attributed to the ionization of tyrosine. The fluorescence is strongly quenched mainly due to the ionized tyrosine residues. The results are discussed in connection with previous investigations on radical formation and inactivation of trypsin after UV irradiation. (orig.)

  7. Direct UV-writing of waveguides

    DEFF Research Database (Denmark)

    Færch, Kjartan Ullitz

    2003-01-01

    The research presented in this phd thesis is concerned about fabrication of waveguide structures in photosensitized germanosilica thin films by exposure to Ultra-violet (UV) radiation. Using a high pressure loading system and a waveguide fabrication setup, planar waveguiding structures with an UV...... induced refractive index change of more than 10-2 have been obtained. New insight, with respect to understanding the UV induced index change obtained by direct UV writing, has been provided, through experiments conducted with such high-pressure loaded germanosilica samples. This include measurements...

  8. Selective isolation of UV-sensitive Rhodopseudomonas sphaeroides mutants

    International Nuclear Information System (INIS)

    Application of penicillin selection method after UV irradiation (λ=254 nm) increases by an order efficiency of mutant selection sensible to ulraviolet radiation (uvs mutants), phototrophic bacterium Rhodopseudomonas sphaeroides induced with nitrosomethylurea (NMM). Over 30% of uvs mutants produced by means of this method possessed increased sensitivity not only to short-wave (sUV, λ=254 nm) but also to long-wave (lUV, λ>280 nm) UV radiations. No correlation in the degree of sensitivity of uvs mutants to sUV and lUV irradiations is discovered. Mutants, which are high-sensitive to lethal effect of lUV, are separated

  9. Ciprofloxacin oxidation by UV-C activated peroxymonosulfate in wastewater

    OpenAIRE

    Mahdi-Ahmed, M.; Chiron, Serge

    2014-01-01

    This work aimed at demonstrating the advantages to use sulfate radical anion for eliminating ciprofloxacin residues from treated domestic wastewater by comparing three UV-254 nm based advanced oxidation processes: UV/persulfate (PDS), UV/peroxymonosulfate (PMS) and UV/H2O2. In distilled water, the order of efficiency was UV/PDS>UV/PMS>UV/H2O2 while in wastewater, the most efficient process was UV/PMS followed by UV/PDS and UV/H2O2 mainly because PMS decomposition into sulfate radical anion wa...

  10. A compilation of genotoxicity and carcinogenicity data on aromatic aminosulphonic acids.

    Science.gov (United States)

    Jung, R; Steinle, D; Anliker, R

    1992-07-01

    A review is presented to evaluate existing information on genotoxicity and carcinogenicity testing of various aromatic aminosulphonic acids (AASAs). A great variety of water-soluble azo dyes can form aromatic phenyl- or naphthyl-aminosulphonic acids by chemical and enzymatic reduction. AASAs are also used as intermediates in the synthesis of azo dyes and azo pigments and can arise as contaminants in the final products. Comparisons have been made with the data available on the corresponding unsulphonated analogues, some of which are known to be genotoxic and/or carcinogenic. The vast majority of the AASAs were conclusively non-mutagenic in the Ames test. In most cases the absence of genotoxicity was also demonstrated with a variety of other test systems in vitro and in vivo. It is concluded that AASAs, in contrast with some of their unsulphonated analogues, generally have no or very low genotoxic and tumorigenic potential.

  11. Gravity-flow alkaline elution: a method to rapidly detect carcinogen-induced DNA strand breaks

    International Nuclear Information System (INIS)

    A rapid, sensitive and reliable gravity-flow alkaline elution assay was developed to detect DNA strand breaks in cultured Madin-Darby bovine kidney epithelial cells. Elution was completed within 2 h without the use of pumps. The system was validated by exposing the cells to X-irradiation (25-1500 R) which resulted in a significant dose dependent response (p less than 0.05) with excellent correlation (r-0.93). The assay reliably detected the DNA damage of seven genotoxic carcinogens. In general, the measured DNA damage was dose dependent and significantly different from control values for all genotoxic carcinogens tested. Six non-genotoxic compounds were tested and showed no detectable DNA damage

  12. Fibrogenic and carcinogenic characteristics of asbestos occurring in Mohmand Agency, northern Pakistan

    International Nuclear Information System (INIS)

    This study has been carried out to identify the fibrogenic and carcinogenic characteristics including the type, physical dimension, and the fiber dose over time-weighted averages (TWA) of asbestos fibers mined, milled and used in Mohamand Agency. Fifteen representative rock and air samples of respirable particulates matter (0.45-10 micro m) collected from various mines and milling units were analyzed using X-Ray Diffraction (XRD). Polarized light Microscope (PLM) and Scanning Electron Microscope (SEM). The types of asbestos were classified as chrysotile, tremolite and anthophyllite. The concentration of asbestos fibers identified in respirable particulates (PM/sub 10. 7. 5. 3. 2. and 8 um long and indicate that the type of asbestos fibers released during mining and milling in Mohamand Agency is potentially carcinogenic. (author)

  13. Signaling by carcinogenic metals and metal-induced reactive oxygen species

    Energy Technology Data Exchange (ETDEWEB)

    Harris, Gabriel Keith; Shi Xianglin

    2003-12-10

    Epidemiological data indicate that exposure to metal and metalloid species, including arsenic (III), chromium (VI), and nickel (II), increases the risk of cancer, particularly of the lung and skin. Alterations in normal signal transduction as a result of exposure to carcinogenic metals, and to metal-catalyzed reactive oxygen species (ROS) formation, appear to play an important role in the etiology of metal-induced carcinogenesis. Signaling components affected by metals include growth factor receptors, G-proteins, MAP kinases, and nuclear transcription factors. This article reviews current literature on the effects of carcinogenic metals and metal-induced ROS on cancer-related signaling pathways. In addition, the mechanisms by which those changes occur, and the role of those changes in carcinogenesis are discussed.

  14. The Effect of UV and Combined Chlorine/UV Treatment on Coliphages in Drinking Water Disinfection

    Directory of Open Access Journals (Sweden)

    Alyaa M. Zyara

    2016-04-01

    Full Text Available Ultraviolet (UV irradiation is a common way to disinfect drinking water, but some viruses are very resistant to UV. Drinking water was disinfected with UV after spiking with MS2 and 18 different coliphages isolated from municipal wastewater effluent. In addition, some coliphages were disinfected with combined treatment of chlorine/UV or vice versa with UV/chlorine. A UV-dose of 22 mWs/cm2 caused less than 2 Log10-reductions of 10 UV-resistant strains, while it caused up to 7 Log10-reductions for 9 UV-sensitive or intermediate strains. The high dose (117 mWs/cm2 caused only 3 Log10-reductions in some UV-resistant coliphages, including MS2, which proved to be a good indicator for viruses in UV-disinfection tests. The combined treatment with 0.1 or 0.5 mg Cl/L (free Cl-dosage 0.04 or 0.2 mg/L, respectively for 10 min followed by UV irradiation of 22 mWs/cm2 inactivated all coliphages tested by >3.6 Log10-units. Synergy was obtained for most coliphages tested by using a Cl/UV combination, and the inactivation using first low Cl-dosages followed by low UV-dosages was higher than if using high Cl- or UV-dosages alone. The opposite treatment with UV/Cl was less effective. Therefore, the combination treatment using first chlorine and then UV can be recommended as a disinfection method for viruses.

  15. Different carcinogenic process in cholangiocarcinoma cases epidemically developing among workers of a printing company in Japan.

    Science.gov (United States)

    Sato, Yasunori; Kubo, Shoji; Takemura, Shigekazu; Sugawara, Yasuhiko; Tanaka, Shogo; Fujikawa, Masahiro; Arimoto, Akira; Harada, Kenichi; Sasaki, Motoko; Nakanuma, Yasuni

    2014-01-01

    Recently, cholangiocarcinoma has epidemically developed among young adult workers of a printing company in Japan. Exposure to organic solvents including 1,2-dichloropropane and/or dichloromethane is supposed to be associated with the carcinoma development. The metabolism of dichloromethane proceeds through a Theta-class glutathione S-transferase (GST) T1-1-catalyzed pathway, where its reactive intermediates have been implicated in genotoxicity and carcinogenicity. This study examined features of the carcinogenic process of the cholangiocarcinoma developed in the printing company. Surgically resected specimens of the cholangiocarcinoma cases were analyzed, where all cases were associated with precursor lesions such as biliary intraepithelial neoplasia (BilIN) and/or intraductal papillary neoplasm of the bile duct (IPNB). Immunohistochemical analysis confirmed constitutional expression of GST T1-1 in normal hepatobiliary tract. Immunostaining of γ-H2AX, a marker of DNA double strand break, showed that its expression was significantly increased in foci of BilIN, IPNB and invasive carcinoma as well as in non-neoplastic biliary epithelial cells of the printing company cases when compared to that of control groups. In the printing company cases, immunohistochemical expression of p53 was observed in non-neoplastic biliary epithelial cells and BilIN-1. Mutations of KRAS and GNAS were detected in foci of BilIN in one out of 3 cases of the printing company. These results revealed different carcinogenic process of the printing company cases, suggesting that the exposed organic solvents might act as a carcinogen for biliary epithelial cells by causing DNA damage, thereby contributing to the carcinoma development.

  16. Evaluation of toxicogenomics approaches for assessing the risk of nongenotoxic carcinogenicity in rat liver.

    Directory of Open Access Journals (Sweden)

    Johannes Eichner

    Full Text Available The current gold-standard method for cancer safety assessment of drugs is a rodent two-year bioassay, which is associated with significant costs and requires testing a high number of animals over lifetime. Due to the absence of a comprehensive set of short-term assays predicting carcinogenicity, new approaches are currently being evaluated. One promising approach is toxicogenomics, which by virtue of genome-wide molecular profiling after compound treatment can lead to an increased mechanistic understanding, and potentially allow for the prediction of a carcinogenic potential via mathematical modeling. The latter typically involves the extraction of informative genes from omics datasets, which can be used to construct generalizable models allowing for the early classification of compounds with unknown carcinogenic potential. Here we formally describe and compare two novel methodologies for the reproducible extraction of characteristic mRNA signatures, which were employed to capture specific gene expression changes observed for nongenotoxic carcinogens. While the first method integrates multiple gene rankings, generated by diverse algorithms applied to data from different subsamplings of the training compounds, the second approach employs a statistical ratio for the identification of informative genes. Both methods were evaluated on a dataset obtained from the toxicogenomics database TG-GATEs to predict the outcome of a two-year bioassay based on profiles from 14-day treatments. Additionally, we applied our methods to datasets from previous studies and showed that the derived prediction models are on average more accurate than those built from the original signatures. The selected genes were mostly related to p53 signaling and to specific changes in anabolic processes or energy metabolism, which are typically observed in tumor cells. Among the genes most frequently incorporated into prediction models were Phlda3, Cdkn1a, Akr7a3, Ccng1 and Abcb4.

  17. Studies on the Mutagenicity and Teratogenicity of Kuianchun and Its Potential Carcinogenicity Prediction

    Institute of Scientific and Technical Information of China (English)

    LIANG Jian-ping; ZHANG Li; CAO Sui-zhong; ZHOU Li-xia; ZHOU Xue-hui; LIU Zong-ping; WEI Chun-mei; MIAO Xiao-lin; WEI Zeng-quan

    2002-01-01

    Kuianchun is a newly synthesized antibacterial and growth-promoting drug. This paper selected a battery of three short-term tests, including Ames test, micronucleus test and sperm abnormality test, to detect the mutagenicity of Kuianchun. The carcinogenicity prediction and battery selection method (CPBS method) was used to determine the probability of carcinogenicity of Kuianchun based upon the results of shortterm tests mentioned above. In addition, traditional teratogenic test was selected to study teratogenicity of Kuianchun. In Ames test, Kuianchun showed mutagenic for Salmonella typhimurium strains TA98 and TA100 in the absence and presence of microsomal metabolic activation system (S9-mix). However, the mutagenicity was reduced by the addition of S9-mix. In micronucleus test, Kuianchun was administered intra-peritoneally to male mouse 30 hours and 6 hours before they were killed respectively. The result indicated that there was no significant difference on the number of micronucleated polychromatic erythrocytes (PCEs) in the mouse bone marrow induced by Kuianchun compared with the negative contrast (50% DMSO) (P > 0.05). In sperm abnormality test, Kuianchun was administered through a gastric incubation to male mouse as a suspension in 2% Tween-80. The dosage levels were 450, 750, 1000 and 1500mg/kg per day for 5 days. The result indicated that the percentage of abnormal sperms induced by Kuianchun was not significant compared with the negative contrast (P>0.05). In traditional teratogenic test, Kuianchun was given orally to pregnant mouse at 1/30,1/20 and 1/15 LDs0 during 6 - 15days of pregnancy period (the LD50 = 9000mg/kg). No toxicity was found either on mother and embryo in mouse, and teratogenic effects were also not observed at all tested dosages. The probability of carcinogenicity of Kuianchun is 23.8 % (θ = 0.238). The result demonstrated that Kuianchun is a non-carcinogen.

  18. N-acetyltransferase 2 genetic polymorphism: Effects of carcinogen and haplotype on urinary bladder cancer risk

    OpenAIRE

    Hein, David W.

    2006-01-01

    A role for the N-acetyltransferase 2 (NAT2) genetic polymorphism in cancer risk has been the subject of numerous studies. Although comprehensive reviews of the NAT2 acetylation polymorphism have been published elsewhere, the objective of this paper is to briefly highlight some important features of the NAT2 acetylation polymorphism that are not universally accepted to better understand the role of NAT2 polymorphism in carcinogenic risk assessment. NAT2 slow acetylator phenotype(s) infer a con...

  19. Ochratoxin A induces rat renal carcinogenicity with limited induction of oxidative stress responses.

    Science.gov (United States)

    Qi, Xiaozhe; Yu, Tao; Zhu, Liye; Gao, Jing; He, Xiaoyun; Huang, Kunlun; Luo, Yunbo; Xu, Wentao

    2014-11-01

    Ochratoxin A (OTA) has displayed nephrotoxicity and renal carcinogenicity in mammals, however, no clear mechanisms have been identified detailing the relationship between oxidative stress and these toxicities. This study was performed to clarify the relationship between oxidative stress and the renal carcinogenicity induced by OTA. Rats were treated with 70 or 210 μg/kg b.w. OTA for 4 or 13 weeks. In the rats administrated with OTA for 13 weeks, the kidney was damaged seriously. Cytoplasmic vacuolization was observed in the outer stripe of the outer medulla. Karyomegaly was prominent in the tubular epithelium. Kidney injury molecule-1 (Kim-1) was detected in the outer stripe of the outer medulla in both low- and high-dose groups. OTA increased the mRNA levels of clusterin in rat kidneys. Interestingly, OTA did not significantly alter the oxidative stress level in rat liver and kidney. Yet, some indications related to proliferation and carcinogenicity were observed. A dose-related increase in proliferating cell nuclear antigen (PCNA) was observed at 4 weeks in both liver and kidney, but at 13 weeks, only in the kidney. OTA down-regulated reactive oxygen species (ROS) and up-regulated vimentin and lipocalin 2 in rat kidney at 13 weeks. The p53 gene was decreased in both liver and kidney at 13 weeks. These results suggest that OTA caused apparent kidney damage within 13 weeks but exerted limited effect on oxidative stress parameters. It implies that cell proliferation is the proposed mode of action for OTA-induced renal carcinogenicity.

  20. On use of the multistage dose-response model for assessing laboratory animal carcinogenicity

    OpenAIRE

    Nitcheva, Daniella; Piegorsch, Walter W.; West, R. Webster

    2007-01-01

    We explore how well a statistical multistage model describes dose-response patterns in laboratory animal carcinogenicity experiments from a large database of quantal response data. The data are collected from the U.S. EPA’s publicly available IRIS data warehouse and examined statistically to determine how often higher-order values in the multistage predictor yield significant improvements in explanatory power over lower-order values. Our results suggest that the addition of a second-order par...

  1. Repair of DNA treated with γ-irradiation and chemical carcinogens. Progress report, 1980-1983

    International Nuclear Information System (INIS)

    We have studied in vitro DNA repair with the isolation and characterization of DNA glycosylases active in the removable of 3-methyladenine and the problem of repair of DNA in chromatin. The second area of focus has been on transposable elements and carcinogen action. The work on DNA adducts with β-propiolactone was done to define potential new substrates useful in a search for new glycosylases

  2. Biomarkers of carcinogen exposure and cancer risk in a coke plant.

    OpenAIRE

    Assennato, G; Ferri, G M; Tockman, M S; Poirier, M C; Schoket, B; Porro, A.; Corrado, V.; Strickland, P T

    1993-01-01

    To evaluate the association between an indicator of carcinogen exposure (peripheral blood leukocyte DNA adducts of polycyclic aromatic hydrocarbons) and an early indicator of neoplastic transformation (sputum epithelial cell membrane antigens binding by monoclonal antibodies against small cell lung cancer and against nonsmall cell lung cancer), a survey of 350 coke-oven workers and 100 unexposed workers was planned. This paper reports a pilot investigation on a subgroup of 23 coke-oven worker...

  3. Mechanism-Based Classification of PAH Mixtures to Predict Carcinogenic Potential.

    Science.gov (United States)

    Tilton, Susan C; Siddens, Lisbeth K; Krueger, Sharon K; Larkin, Andrew J; Löhr, Christiane V; Williams, David E; Baird, William M; Waters, Katrina M

    2015-07-01

    We have previously shown that relative potency factors and DNA adduct measurements are inadequate for predicting carcinogenicity of certain polycyclic aromatic hydrocarbons (PAHs) and PAH mixtures, particularly those that function through alternate pathways or exhibit greater promotional activity compared to benzo[a]pyrene (BaP). Therefore, we developed a pathway-based approach for classification of tumor outcome after dermal exposure to PAH/mixtures. FVB/N mice were exposed to dibenzo[def,p]chrysene (DBC), BaP, or environmental PAH mixtures (Mix 1-3) following a 2-stage initiation/promotion skin tumor protocol. Resulting tumor incidence could be categorized by carcinogenic potency as DBC > BaP = Mix2 = Mix3 > Mix1 = Control, based on statistical significance. Gene expression profiles measured in skin of mice collected 12 h post-initiation were compared with tumor outcome for identification of short-term bioactivity profiles. A Bayesian integration model was utilized to identify biological pathways predictive of PAH carcinogenic potential during initiation. Integration of probability matrices from four enriched pathways (P < .05) for DNA damage, apoptosis, response to chemical stimulus, and interferon gamma signaling resulted in the highest classification accuracy with leave-one-out cross validation. This pathway-driven approach was successfully utilized to distinguish early regulatory events during initiation prognostic for tumor outcome and provides proof-of-concept for using short-term initiation studies to classify carcinogenic potential of environmental PAH mixtures. These data further provide a 'source-to-outcome' model that could be used to predict PAH interactions during tumorigenesis and provide an example of how mode-of-action-based risk assessment could be employed for environmental PAH mixtures. PMID:25908611

  4. Quantitative assessment of exposure and risk for three carcinogenics in long-standing pollution sites

    International Nuclear Information System (INIS)

    The project attempts a quantitative assessment of risks for three carcinogenics that are common in sites of long-standing pollution. Benzo(a)pyrene stands for the group of polycyclic aromatic hydrocarbons, cadmium for heavy metals, and benzene for volatile aromatic compounds. The report discusses the general fundamentals of exposure and risk assessment. The exposure model is described in detail and applied to the three test substances. (orig./MG)

  5. Carcinogenicity tests of N-nitroso derivatives of two drugs, phenmetrazine and methylphenidate

    Energy Technology Data Exchange (ETDEWEB)

    Lijinsky, W.; Taylor, H.W.

    1976-01-01

    Two commonly used drugs that are derivatives of cyclic secondary amines, phenmetrazine and methylphenidate, were converted to their N-nitroso derivatives by reaction with nitrite in acid solution, and the products were tested by chronic administration to rats in doses comparable with those used to test the unsubstituted parent nitrosamines. No tumors were seen that could be attributed to these nitrosamines, and it is concluded that, under these conditions, neither compound is carcinogenic.

  6. Gene–environment interactions between DNA repair polymorphisms and exposure to the carcinogen vinyl chloride

    OpenAIRE

    Li, Yongliang; Marion, Marie-Jeanne; Zipprich, Jennifer; Santella, Regina M.; Freyer, Greg; Brandt-Rauf, Paul W.

    2009-01-01

    We have recently suggested that polymorphisms in metabolism and repair pathways may play a role in modulating the effects of exposure to the carcinogen vinyl chloride in the production of biomarkers of its mutagenic damage. The aim of the present study was to extend these observations by examining gene–environment interactions between several common polymorphisms in the DNA repair genes XRCC1 and ERCC2/XPD and vinyl chloride exposure on the production of vinyl chloride-induced biomarkers of m...

  7. Degradation mechanisms of geosmin and 2-MIB during UV photolysis and UV/chlorine reactions.

    Science.gov (United States)

    Kim, Tae-Kyoung; Moon, Bo-Ram; Kim, Taeyeon; Kim, Moon-Kyung; Zoh, Kyung-Duk

    2016-11-01

    We conducted chlorination, UV photolysis, and UV/chlorin reactions to investigate the intermediate formation and degradation mechanisms of geosmin and 2-methylisoborneol (2-MIB) in water. Chlorination hardly removed geosmin and 2-MIB, while the UV/chlorine reaction at 254 nm completely removed geosmin and 2-MIB within 40 min and 1 h, respectively, with lesser removals of both compounds during UV photolysis. The kinetics during both UV photolysis and UV/chlorine reactions followed a pseudo first-order reaction. Chloroform was found as a chlorinated intermediate during the UV/chlorine reaction of both geosmin and 2-MIB. The pH affected both the degradation and chloroform production during the UV/chlorine reaction. The open ring and dehydration intermediates identified during UV/chlorine reactions were 1,4-dimethyl-adamantane, and 1,3-dimethyl-adamantane from geosmin, 2-methylenebornane, and 2-methyl-2-bornene from 2-MIB, respectively. Additionally, 2-methyl-3-pentanol, 2,4-dimethyl-1-heptene, 4-methyl-2-heptanone, and 1,1-dichloro-2,4-dimethyl-1-heptane were newly identified intermediates from UV/chlorine reactions of both geosmin and 2-MIB. These intermediates were degraded as the reaction progressed. We proposed possible degradation pathways during the UV photolysis and UV/chlorine reactions of both compounds using the identified intermediates.

  8. Potential carcinogenicity of foundry fumes: a comparative in vivo-in vitro study.

    Science.gov (United States)

    Humfrey, C D; Levy, L S; Faux, S P

    1996-01-01

    Epidemiological studies of workers exposed to fumes in the iron and steel foundry industry have consistently demonstrated an increased relative risk of lung cancer of approximately 1.4. Foundry fume is a complex mixture of gases and fine particles generated during the casting process when molten metal is poured into sand moulds bound together with organic binders. The chemical composition of fume varies according to foundry process and, specifically, binder composition. Previous in vitro studies have demonstrated that some fumes have mutagenic activity and that this varies with fume type. The current study has examined the potential carcinogenicity of three fumes in a 2-yr in vivo rodent bioassay using an intrabronchial pellet implantation technique. The toxicity and genotoxicity of the fumes were tested concurrently in a number of in vitro assays including those identifying mutagenicity, unscheduled DNA synthesis, free radical DNA damage and micronucleus induction. The rodent bioassay failed to demonstrate a carcinogenic response, although an increase in preneoplastic lesions was seen in all fume-treated groups relative to controls. When tested in vitro, the fumes were positive in many assays and activity correlated with the polycyclic aromatic hydrocarbon content of the fumes. The employment of a combination of in vitro assays for different genotoxic endpoints, such as those presented in the current study, provides information useful for the overall assessment of carcinogenicity of complex mixtures such as foundry fume. PMID:9119322

  9. TLR2 controls intestinal carcinogen detoxication by CYP1A1

    DEFF Research Database (Denmark)

    Do, Khoa Ngyuen; Nielsen Fink, Lisbeth; Elbenhardt Jensen, Thomas;

    2012-01-01

    Intestinal cytochrome P450 subclass 1A1 (CYP1A1) contributes to a metabolic "shield" protecting the host from ingested carcinogens such as polycyclic aromatic hydrocarbons (PAH). The expression of CYP1 (including CYP1A2 and CYP1B1) is considered to depend solely on a heterodimeric transcription f...... of intestinal microbiota when trying to unravel pathways present in mammals and opens new perspectives for research in human health.......Intestinal cytochrome P450 subclass 1A1 (CYP1A1) contributes to a metabolic "shield" protecting the host from ingested carcinogens such as polycyclic aromatic hydrocarbons (PAH). The expression of CYP1 (including CYP1A2 and CYP1B1) is considered to depend solely on a heterodimeric transcription...... cells and enterocytes. Here we report that intestinal CYP1A1 is silenced in TLR2-deficient mice, even when under exposure to the carcinogenic PAH benzo[a]pyrene (BaP). In contrast, hepatic CYP1A1 was moderately induced in TLR2-deficient mice without restoring their ability to clear BaP from systemic...

  10. Two-year carcinogenicity study of acrylamide in Wistar Han rats with in utero exposure.

    Science.gov (United States)

    Maronpot, R R; Thoolen, R J M M; Hansen, B

    2015-02-01

    Acrylamide is an important chemical with widespread industrial and other uses in addition to generalized population exposure from certain cooked foods. Previous rat studies to assess the carcinogenic potential of acrylamide have been carried out exclusively in the Fischer 344 rat with identification of a number of tumors amongst which mesotheliomas of the tunica vaginalis is an important tumor endpoint in the classification of acrylamide as a 'probably human carcinogen. In a rat carcinogenicity study to determine the human relevance of mesotheliomas Wistar Han rats were exposed to 0, 0.5, 1.5, or 3.0mg acrylamide/kg body weight/day in drinking water starting at gestation day 6. At the end of two years, mammary gland fibroadenomas in females and thyroid follicular cell tumors in both sexes were the only tumors increased in acrylamide treated rats. These tumor endpoints have rat-specific modes of action suggesting less likelihood of human cancer risk than previously estimated. This study demonstrates that tunica vaginalis mesotheliomas are strain specific and not likely of genotoxic origin.

  11. Chronic Dermal Toxicity of Epoxy Resins I. Skin Carcinogenic Potency and General Toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Holland, J.M.

    2001-01-16

    Epoxy resins are a diverse class of chemicals that differ in structure, physical properties, and, presumably, biological activity. The purpose of these experiments was to compare the chronic dermal toxicity and carcinogenicity of selected commercial epoxy resins and to determine the potential for positive synergistic carcinogenic interactions between different resins. This work is an extension and continuation of a Department of Energy sponsored program to evaluate epoxy resins for potential occupational health risks. The materials examined were chosen on the basis of their interest to the U.S. government. They are representative of the manufacturer's production at the time, and therefore the data are completely valid only for the specific production period. Results of the experimental exposures will be reported in two parts. This report describes the test materials, their chemical and physical characteristics and the experimental design. General (systemic) toxicity will be evaluated and the skin carcinogenicity of the materials compared. A subsequent report will provide morphological descriptions of skin and significant internal pathology induced by the various treatments.

  12. Synthesis, structural characterization and anti-carcinogenic activity of new cyclotriphosphazenes containing dioxybiphenyl and chalcone groups

    Science.gov (United States)

    Görgülü, Ahmet Orhan; Koran, Kenan; Özen, Furkan; Tekin, Suat; Sandal, Süleyman

    2015-05-01

    2,2-Dichloro-4,4,6,6-bis[spiro(2‧,2″-dioxy-1‧,1″-biphenylyl]cyclotriphosphazene (2) was synthesized from hexachlorocyclotriphosphazene (HCCP) and 2,2‧-dihydroxybiphenyl. The mixed substituent chalcone/dioxybiphenyl cyclophosphazenes (2a-h) were obtained from the reactions of (2) with hydroxy chalcone compounds in K2CO3/acetone system. The chalcone-cyclophosphazene compounds were characterized by elemental analysis, FT-IR, 1H, 13C, 31P NMR techniques. In vitro anti-carcinogenic activities of all compounds were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Anti-carcinogenic activity of the compounds (2a-h) against androgen-dependent (LNCaP) and independent (PC-3) human prostate cancer cell lines were investigated. Our results indicate that the chalcone-phosphazene compounds (2a-h) have anti-carcinogenic activity on PC-3 and LNCaP cell lines (p < 0.05). The effective dose of the compounds was determined as 100 μM.

  13. DNA repair of UV photoproducts and mutagenesis in human mitochondrial DNA

    International Nuclear Information System (INIS)

    The induction and repair of DNA photolesions and mutations in the mitochondrial (mt) DNA of human cells in culture were analysed after cell exposure to UV-C light. The level of induction of cyclobutane pyrimidine dimers (CPD) in mitochondrial and nuclear DNA was comparable, while a higher frequency of pyrimidine (6-4) pyrimidone photoproducts (6-4 PP) was detected in mitochondrial than in nuclear DNA. Besides the known defect in CPD removal, mitochondria were shown to be deficient also in the excision of 6-4 PP. The effects of repair-defective conditions for the two major UV photolesions on mutagensis was assessed by analysing the frequency and spectrum of spontaneous and UV-induced mutations by restriction site mutation (RSM) method in a restriction endonuclease site, NciI (5'CCCGG3') located within the coding sequence of the mitochondrial gene for tRNA Leu. The spontaneous mutation frequency and spectrum at the NciI site of mitochondrial DNA was very similar to the RSM background mutation frequency (approximately 10-5) and type (predominantly GC > AT transitions at GL1) of the NciI site). Conversely, an approximately tenfold increase over background mutation frequency was recorded after cell exposure to 20 J/m2. In this case, the majority of mutations were C > T transitions preferentially located on the non-transcribed DNA strand at C1 and C2 of the NciI site. This mutation spectrum is expected by UV mutagenesis. This is the first evidence of induction of mutations in mitochondrial DNA by treatment of human cells with a carcinogen. (author)

  14. Liver-targeting macromolecular MRI contrast agents

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Macromolecular ligands with liver-targeting group (pyridoxamine, PM) PHEA-DTPA-PM and PAEA-DTPA-PM were prepared by the incorporation of different amount of diethylenetriaminepentaacetic acid monopyridoxamine group (DTPA-PM) into poly-a, b-[N-(2-hydroxyethyl)-L- aspartamide] (PHEA) and poly-a, b-[N-(2-aminoethyl)-L-aspartamide] (PAEA). The macromolecular ligands thus obtained were further complexed with gadolinium chloride to give macromolecular MRI contrast agents with different Gd(Ⅲ) contents. These macromolecular ligands and their gadolinium complexes were characterized by 1H NMR, IR, UV and elementary analysis. Relaxivity studies showed that these polyaspartamide gadolinium complexes possess higher relaxation effectiveness than that of the clinically used Gd-DTPA. Magnetic resonance imaging of the liver in rats and experimental data of biodistribution in mice indicate that these macromolecular MRI contrast agents containing pyridoxamine exhibit liver-targeting property.

  15. A comparison of herpes simplex virus plaque development after viral treatment with anti-DNA or antilipid agents.

    OpenAIRE

    Coohill, T P; Babich, M; Taylor, W.D.; Snipes, W

    1980-01-01

    The plaque development of Herpes simplex virus type 1 (HSV) is slower for viruses treated with two anti-DNA agents: ultraviolet radiation (UV) or n-acetoxy-2-acetyl-aminofluorene. For HSV treated with three antimembrane agents--butylated hydroxytoluene, acridine plus near UV radiation, or ether--the plaque development time is the same as for untreated viruses. These differences hold even for viruses that survived treatment that lowered viability below the 1% level. Gamma ray inactivation of H...

  16. THE INTEGRATED AGENT IN MULTI-AGENT SYSTEMS

    OpenAIRE

    Maleković, Mirko; Čubrilo, Mirko

    2000-01-01

    [n this paper, we characterize the integrated agent in multi-agent systems. The following result is proved: if a multi-agent system is reflexive (symmetric, transitive, Euclidean) then the integrated agent of the multi-agent system is reflexive (symmetric, transitive, Euclidean), respectively. We also prove that the analogous result does not hold for multi-agent system's serial ness. A knowledge relationship between the integrated agent and agents in a multiagent system is presented.

  17. Discontinuities during UV writing of waveguides

    DEFF Research Database (Denmark)

    Svalgaard, Mikael; Harpøth, Anders; Andersen, Marc

    2005-01-01

    UV writing of waveguides can be hampered by discontinuities where the index change process suddenly shuts down. We show that thermal effects may account for this behaviour.......UV writing of waveguides can be hampered by discontinuities where the index change process suddenly shuts down. We show that thermal effects may account for this behaviour....

  18. The UV Properties of SDSS Selected Quasars

    CERN Document Server

    Trammell, G B; Schneider, D P; Richards, G T; Hall, P B; Anderson, S F; Brinkmann, J; Trammell, George B.; Berk, Daniel E. Vanden; Schneider, Donald P.; Richards, Gordon T.; Hall, Patrick B.; Anderson, Scott F.

    2006-01-01

    We present an analysis of the broadband UV/optical properties of z<3.4 quasars matched in the Galaxy Evolution Explorer (GALEX) General Data Release 1 (GR1) and the Sloan Digital Sky Survey Data Release 3 (SDSS DR3). Of the 6371 DR3 quasars covered by 204 GR1 tiles, 5380 have near-UV detections, while 3034 have both near-UV and far-UV detections using a matching radius of 7". Most of the DR3 sample quasars are detected in the near-UV until z~1.7, with the near-UV detection fraction dropping to ~50% by z~2. Statistical tests performed on the distributions of non-detections indicate that the optically-selected quasars missed in the UV tend to be optically faint or at high redshift. The GALEX positions are shown to be consistent with the SDSS astrometry to within an rms scatter of 0.6-0.7" in each coordinate, and empirically determined photometric errors from multi-epoch GALEX observations significantly exceed the Poissonian errors quoted in the GR1 object catalogs. The UV-detected quasars are well separated ...

  19. Exposure to solar UV in Finland

    Energy Technology Data Exchange (ETDEWEB)

    Jokela, K.; Leszczynski, K.; Visuri, R.; Ylianttila, L. [Finnish Centre for Radiation and Nuclear Safety, Helsinki (Finland)

    1995-12-31

    Exceptionally low total ozone, up to 40 % below the normal level, was measured over Northern Europe during winter and spring in 1992 and 1993. In 1993 the depletion persisted up to the end of May, resulting in a significant increase in biologically effective ultraviolet (UV) radiation. The increases were significantly smaller in 1992 and 1994 than in 1993. A special interest in Northern Europe is the effect of high reflection of UV from the snow. The period from the mid March to the mid May is critical in Northern Finland, because in that time the UV radiation is intense enough to cause significant biological effects, and the UV enhancing snow still covers the ground. Moreover, there is some evidence of increasing springtime depletions of ozone over Arctic regions. In this study the increase of UV exposure associated with the ozone depletions was examined with measurements and theoretical calculations. The measurements were carried out with spectroradiometrically calibrated Solar Light Model 500 and 501 UV radiometers which measure the erythemally effective UV doses and dose rates. The theoretical UV doses and dose rates were computed with the clear sky model of Green

  20. PUMA promotes Bax translocation by competitive binding to Bcl-Xl during UV-induced apoptosis

    Science.gov (United States)

    Zhang, Yingjie; Xing, Da; Wu, Yinyuan; Liu, Lei

    2008-02-01

    Ultraviolet (UV) irradiation can induce apoptosis through both the membrane death receptor and the intrinsic apoptotic signaling pathways as DNA-damaging agents. PUMA, a BH3-only Bcl-2 family protein, plays an essential role in DNA damage-induced apoptosis. Bax, also a Bcl-2 family member, translocates from the cytosol to the mitochondrial membrane during UV-induced apoptosis. However, the regulation of Bax activation induced by UV irradiation remains poorly understood. In this study, the FRET (fluorescence resonance energy transfer) technique was used to study the interactions of Bax, Bcl-Xl, and PUMA in ASTC-a-1 cells. The results show that Bax translocated from the cytosol to the mitochondrial membrane at about 7 h after UV irradiation, and the translocation can not be blocked completely when overexpressed Bcl-xl. Moreover, The interaction of Bax and Bcl-Xl weakened markedly. In addition, Co-immunoprecipitation shows that PUMA released Bax by directly binding to Bcl-XL after UV irradiation in ASTC-a-1 cells. Taken together, these results indicated that PUMA can promote Bax translocation by binding to Bcl-Xl during UV-induced apoptosis.

  1. Effect of UV-C irradiation on growth, sporulation and pathogenicity of cochliobolus sativus isolates

    International Nuclear Information System (INIS)

    More than 30 isolates of Cochliobolus sativus, the causal agent of common root rot disease; were collected from different regions of Syria. Seven of them were exposed to UV-C light for 40 or 60 h . at a dose rate of 2.52x10-3 W/cm2. A significant increases in the mycelium growth and sporulation were detected (p<0.001). Within the studied range of UV wave length, these two parameters were increased upon increasing the period of exposure to UV-C light. The pathogenicity of four isolates was evaluated after 60 h. of UV irradiation. The response to UV irradiation varied among these isolates, and resulted in an increase in their virulence level (as assessed by evaluating disease severity on sub-crown internodes). Five barley genotypes possessing different levels of resistance to C. sativus were studied. Arabi Abiad was the most susceptible cultivar whereas, Taka 76 line was moderately susceptible. It is concluded that it is possible to implement the positive effect of low doses of UV-C in stimulating the sporulation of fungi, which are difficult to sporulate on artificial media. (author)

  2. Andrographolide Sodium Bisulfate Prevents UV-Induced Skin Photoaging through Inhibiting Oxidative Stress and Inflammation

    Directory of Open Access Journals (Sweden)

    Janis Ya-Xian Zhan

    2016-01-01

    Full Text Available Andrographolide sodium bisulfate (ASB, a water-soluble form made from andrographolide through sulfonating reaction, is an antioxidant and anti-inflammatory drug; however, the antiphotoaging effect of ASB has still not been revealed. Oxidative stress and inflammation are known to be responsible for ultraviolet (UV irradiation induced skin damage and consequently premature aging. In this study, we aimed at examining the effect of ASB on UV-induced skin photoaging of mice by physiological and histological analysis of skin and examination of skin antioxidant enzymes and immunity analyses. Results showed that topical administration of ASB suppressed the UV-induced skin thickness, elasticity, wrinkles, and water content, while ASB, especially at dose of 3.6 mg/mouse, increased the skin collagen content by about 53.17%, decreased the epidermal thickness by about 41.38%, and prevented the UV-induced disruption of collagen fibers and elastic fibers. Furthermore, ASB decreased MDA level by about 40.21% and upregulated the activities of SOD and CAT and downregulated the production of IL-1β, IL-6, IL-10, and TNF-α in UV-irradiated mice. Our study confirmed the protective effect of ASB against UV-induced photoaging and initially indicated that this effect can be attributed to its antioxidant and anti-inflammatory activities in vivo, suggesting that ASB may be a potential antiphotoaging agent.

  3. Andrographolide Sodium Bisulfate Prevents UV-Induced Skin Photoaging through Inhibiting Oxidative Stress and Inflammation.

    Science.gov (United States)

    Zhan, Janis Ya-Xian; Wang, Xiu-Fen; Liu, Yu-Hong; Zhang, Zhen-Biao; Wang, Lan; Chen, Jian-Nan; Huang, Song; Zeng, Hui-Fang; Lai, Xiao-Ping

    2016-01-01

    Andrographolide sodium bisulfate (ASB), a water-soluble form made from andrographolide through sulfonating reaction, is an antioxidant and anti-inflammatory drug; however, the antiphotoaging effect of ASB has still not been revealed. Oxidative stress and inflammation are known to be responsible for ultraviolet (UV) irradiation induced skin damage and consequently premature aging. In this study, we aimed at examining the effect of ASB on UV-induced skin photoaging of mice by physiological and histological analysis of skin and examination of skin antioxidant enzymes and immunity analyses. Results showed that topical administration of ASB suppressed the UV-induced skin thickness, elasticity, wrinkles, and water content, while ASB, especially at dose of 3.6 mg/mouse, increased the skin collagen content by about 53.17%, decreased the epidermal thickness by about 41.38%, and prevented the UV-induced disruption of collagen fibers and elastic fibers. Furthermore, ASB decreased MDA level by about 40.21% and upregulated the activities of SOD and CAT and downregulated the production of IL-1β, IL-6, IL-10, and TNF-α in UV-irradiated mice. Our study confirmed the protective effect of ASB against UV-induced photoaging and initially indicated that this effect can be attributed to its antioxidant and anti-inflammatory activities in vivo, suggesting that ASB may be a potential antiphotoaging agent. PMID:26903706

  4. Sensitivity of pathogenic and free-living Leptospira spp. to UV radiation and mitomycin C

    Energy Technology Data Exchange (ETDEWEB)

    Stamm, L.V.; Charon, N.W.

    1988-03-01

    The habitats for the two major Leptospira spp. differ. The main habitat of L. biflexa is soil and water, whereas L. interrogans primarily resides in the renal tubules of animals. We investigated whether these two species, along with L. illini (species incertae sedis), differ with respect to their sensitivity to UV radiation. The doses of UV resulting in 37, 10 and 1% survival were determined for representive serovars from each species. L. interrogans serovar pomona was 3.0 to 4.8 times more sensitive to UV than the other Leptospira species under the 37, 10, and 1% survival parameters. In comparison to other bacteria, L. interrogans serovar pomona is among the most sensitive to UV. In a qualitative UV sensitivity assay., L. interrogans serovars were found to be in general more sensitive than L. biflexa serovars. All three species were found to have a photoreactivation DNA repair mechanism. Since organisms that are resistant to UV are often resistant to the DNA cross-linking agent mitomycin C, we tested the relative sensitivity of several Leptospira serovars to this compound. With few exceptions, L. biflexa and L. illini serovars were considerably more resistant to mitomycin C than the L. interrogans serovars. The mitomycin C sensitivity assay could be a useful addition to current characterization tests used to differentiate the Leptospira species.

  5. Heuristic optimization of a continuous flow point-of-use UV-LED disinfection reactor using computational fluid dynamics.

    Science.gov (United States)

    Jenny, Richard M; Jasper, Micah N; Simmons, Otto D; Shatalov, Max; Ducoste, Joel J

    2015-10-15

    Alternative disinfection sources such as ultraviolet light (UV) are being pursued to inactivate pathogenic microorganisms such as Cryptosporidium and Giardia, while simultaneously reducing the risk of exposure to carcinogenic disinfection by-products (DBPs) in drinking water. UV-LEDs offer a UV disinfecting source that do not contain mercury, have the potential for long lifetimes, are robust, and have a high degree of design flexibility. However, the increased flexibility in design options will add a substantial level of complexity when developing a UV-LED reactor, particularly with regards to reactor shape, size, spatial orientation of light, and germicidal emission wavelength. Anticipating that LEDs are the future of UV disinfection, new methods are needed for designing such reactors. In this research study, the evaluation of a new design paradigm using a point-of-use UV-LED disinfection reactor has been performed. ModeFrontier, a numerical optimization platform, was coupled with COMSOL Multi-physics, a computational fluid dynamics (CFD) software package, to generate an optimized UV-LED continuous flow reactor. Three optimality conditions were considered: 1) single objective analysis minimizing input supply power while achieving at least (2.0) log10 inactivation of Escherichia coli ATCC 11229; and 2) two multi-objective analyses (one of which maximized the log10 inactivation of E. coli ATCC 11229 and minimized the supply power). All tests were completed at a flow rate of 109 mL/min and 92% UVT (measured at 254 nm). The numerical solution for the first objective was validated experimentally using biodosimetry. The optimal design predictions displayed good agreement with the experimental data and contained several non-intuitive features, particularly with the UV-LED spatial arrangement, where the lights were unevenly populated throughout the reactor. The optimal designs may not have been developed from experienced designers due to the increased degrees of

  6. Cytotoxicity and chromosome aberrations in normal human oral keratinocytes induced by chemical carcinogens: Comparison of inter-individual variations.

    Science.gov (United States)

    Tsutsui, T; Kawamoto, Y; Suzuki, N; Gladen, B C; Barrett, J C

    1991-01-01

    Normal human keratinocytes from the oral cavity were cultured in vitro in serum-free medium. Cultures from different individuals were established, and the responses of the cells to different chemicals were compared. The cells, grown at clonal densities, were treated separately with an alkylating agent (N-methyl-N'-nitro-N-nitrosoguanidine; MNNG), two arsenical salts (sodium arsenate or sodium arsenite), sodium fluoride or two polyaromatic hydrocarbons (benzo[a]pyrene or 7,12-dimethylbenz[a]-anthracene). There were no significant differences in the colony-forming efficiencies (22.8 +/- 4.2%) of control (untreated) cells from five different individuals. At selected doses, each of the chemicals reduced the colony-forming efficiencies of the treated cells. The cytotoxicity of most of the chemicals did not differ significantly among cells derived from different individuals, with the exception of sodium arsenate at two doses and sodium fluoride at the highest dose tested. Induction of chromosome aberrations by MNNG, sodium arsenite, sodium arsenate and sodium flouride was analysed with cells derived from up to nine individuals. There was little difference in the inducibilities of chromosome aberrations among cultured keratinocytes from different donors. Treatment of cells from nine donors with one dose of sodium fluoride revealed a statistically significant inter-individual variation. These findings provide a model system to study the effects of carcinogens on the target cells for oral cancers. The results can be compared with findings for cells from other epithelial tissues, since the culture conditions support the growth of keratinocytes regardless of origin. Little inter-individual variation was observed in the response of oral keratinocytes to the chemicals examined.

  7. Study of UV fiber's mechanical properties

    Institute of Scientific and Technical Information of China (English)

    Feng TU; Xinwei QIAN; Deming LIU; Shuqiang ZHANG; Jie LUO; Tao DENG; Chen YANG; Jiangtao GUO

    2009-01-01

    A number of spectroscopic techniques make use of ultra violet (UV) absorbance and luminescence measurements to characterize materials, for use in medical/pharmaceutical applications, for forensic and sensor applications, and for remote detection or monitoring,especially for hazardous environments.Furthermore, many high-power applications in medicine and industry are looking forward to using UV wavelengths.The UV fiber's mechanical reliability has become one of the most crucial performances with longer length fiber being used.This paper reviews the researched evolvement of the normal single mode fiber's mechanical reliability.Based on the standard measure method of the normal fiber, the mechanical reliability of the UV fiber has been researched.The measurement results show the difference of mechanical reliability between the different doping composition UV fibers.

  8. Azoreductase activity of Sprague Dawley and Wistar-derived rats towards both carcinogenic and non-carcinogenic analogues of 4-dimethylaminophenylazobenzene (DAB).

    Science.gov (United States)

    Elliott, B M

    1984-08-01

    Azoreductase activity towards the hepatocarcinogen p-dimethylaminophenylazobenzene (DAB) and four analogues has been measured in vitro in the liver and caecum of Sprague Dawley (Alpk/SD) and Alderley Park (Alpk/AP Wistar-derived) rats. Two carcinogenic DAB analogues, 3'-methyl-p-dimethylaminophenylazobenzene (3M) and 6-p-dimethylaminophenylazobenzothiazole (6BT) and two non-carcinogenic analogues, 4-N-pyrrolidinylazobenzene (4N) and 5-p-dimethylaminophenylazoindazole (5I) have been examined. The azoreductase activity towards DAB of a 9000 g supernatant of liver homogenate was greater in the SD than the AP strain between 6 and 13 weeks of age, but comparable to that of AP rats at 4 weeks of age. The activity towards DAB fell in both strains with increasing age. Animals of both strains fed a riboflavin-low diet (2-3 mg kg-1) had reduced azoreductase activity with DAB when compared to a standard diet at all ages studied, although the difference was less marked in the AP rats. 3M and 4N were azoreduced by the livers of both strains of rat fed a standard diet at a rate of approximately 50% of that of DAB, whereas 5I and 6BT were cleaved at a much lower rate (5-20%). All the chemicals were reduced by an oxygen-insensitive enzyme in the liver preparation, as has previously been reported for DAB. DAB, 3M and 6BT were reduced at a similar rate to each other by a fraction containing caecal contents, both in and between the two strains of rat. Similarly, 4N and 5I were reduced by a caecal preparation at a similar rate to each other in and between both strains of rat, but at a rate of only 30-50% that shown by DAB, 3M and 6BT. In contrast to the conditions required by the liver azoreductase enzyme, anaerobic conditions were required for maximal activity of the caecal preparation. Liver azoreductase activity towards all the DAB analogues was reduced in both strains of rat maintained on a riboflavin-low diet, while the caecal azoreductase activity was unaffected. Neither the

  9. Discrepancy of whiteness and UV protection in wet state.

    Science.gov (United States)

    Tarbuk, Anita; Grancarić, Ana Marija; Situm, Mirna

    2014-12-01

    The incidence of skin cancer is increasing by epidemic proportions. Basal cell cancer remains the most common skin neoplasm, and simple excision is generally curative. On the other hand, aggressive local growth and metastasis are common features of malignant melanoma, which accounts for 75 percent of all deaths associated with skin cancer. In Croatia only, more than 20,000 new cases of skin cancer has been diagnosed in 2008 of which melanoma 286 new cases and 118 yearly deaths in men, and 275 new cases and 79 deaths in women population. The back sides in men and women, as well as the lower limbs in women, are the most common site for melanomas. The primary cause of skin cancer is believed to be a long exposure to solar ultraviolet (UV) radiation crossed with the amount of skin pigmentation in the population. There are indications that other parts of solar spectrum (e.g., blue light) might also have effects on skin and eyes. Most people think all clothing will protect them, but that's not the case. UV clothing can show UVprotection, but in the most cases it does not provide full sun screening properties. UV protection ability highly depends on large number of factors such are type of fiber, fabric surface and construction, type and concentration of dyestuff, fluorescent whitening agent (FWA), UV-B protective agents, as well as nanoparticles, if applied. For that reason, jeans and tightly woven fabrics offer a very good level of protection. However, on a hot summer day, those aren't the kinds of clothing people usually reach for. More often, when they are on the beach, they wear T-shirt, as well during the swimming in the sea, thinking that it will protect them. Therefore, in this paper the discrepancy of UVprotection in wet state was researched. For the purpose, FWA and UVabsorber were applied in wide concentration range to white cotton knit fabrics commonly used for T-shirts. Afterwards, the discrepancy in whiteness and UVprotection was research in distilled water

  10. Liver fatty acid-binding protein: specific mediator of the mitogenesis induced by two classes of carcinogenic peroxisome proliferators.

    OpenAIRE

    S H Khan; Sorof, S

    1994-01-01

    Peroxisome proliferators (PP) are a diverse group of chemicals that induce dramatic increases in peroxisomes in rodent hepatocytes, followed by hypertrophy, hepatomegaly, alterations in lipid metabolism, mitogenesis, and finally hepatocarcinomas. Termed nongenotoxic carcinogens, they do not interact with DNA, are not mutagenic in bacterial assays, and fail to elicit many of the phenotypes associated with classic genotoxic carcinogens. We report here that the mitogenesis induced by the major P...

  11. The metabolic N-oxidation of carcinogenic arylamines in relation to nitrogen charge density and oxidation potential.

    OpenAIRE

    Kadlubar, F F; Fu, P P; Jung, H.; Shaikh, A U; Beland, F A

    1990-01-01

    The N-oxidation of carcinogenic arylamines to form N-hydroxy arylamines has long been regarded as a necessary metabolic step for conversion to proximate carcinogenic derivatives. In contrast, arylamine ring-oxidation has been generally considered to be an important detoxification mechanism. Both enzymatic reactions are carried out in the liver and usually involve the cytochrome P-450 monooxygenases. Studies on the metabolic oxidation of certain arylamines have indicated that the relative char...

  12. UV/Vis/NIR Spectroelectrochemistry

    Science.gov (United States)

    Neudeck, Andreas; Marken, Frank; Compton, Richard G.

    Voltammetric techniques used in electrochemistry monitor the flow of current as a function of potential, time, and mass transport. A huge variety of different experiments are possible, giving information about reaction energies, reaction intermediates, and the kinetics of a process [1-4]. However, additional data are often required and are accessible, in particular, via in situ spectroelectrochemical approaches. By coupling a spectroscopic technique such as UV/Vis/NIR spectroscopy [5, 6] to an electrochemical experiment, a wealth of complementary information as a function of the potential, time, and mass transport is available. In a recently published book dedicated to spectroelectrochemical techniques [7] the diversity of methods and new chemical information obtained is apparent. Both spectroscopic information about short-lived unstable intermediates and spectroscopic information disentangling the composition of complex mixtures of reactants can be obtained. Figure II.6.1 shows a schematic diagram for the case of a computer-controlled potentiostat system connected to a conventional electrochemical cell (working electrode WE, reference electrode RE, counter electrode CE) and simultaneously controlling the emitter and detector of a spectrometer. This kind of experimental arrangement allows the electrochemical and the spectroscopic data to be recorded simultaneously and, therefore, in contrast to the analysis of two independent data sets, direct correlation of data as a function of time and potential is possible.

  13. Chemical crowd control agents.

    Science.gov (United States)

    Menezes, Ritesh G; Hussain, Syed Ather; Rameez, Mansoor Ali Merchant; Kharoshah, Magdy A; Madadin, Mohammed; Anwar, Naureen; Senthilkumaran, Subramanian

    2016-03-01

    Chemical crowd control agents are also referred to as riot control agents and are mainly used by civil authorities and government agencies to curtail civil disobedience gatherings or processions by large crowds. Common riot control agents used to disperse large numbers of individuals into smaller, less destructive, and more easily controllable numbers include chloroacetophenone, chlorobenzylidenemalononitrile, dibenzoxazepine, diphenylaminearsine, and oleoresin capsicum. In this paper, we discuss the emergency medical care needed by sufferers of acute chemical agent contamination and raise important issues concerning toxicology, safety and health. PMID:26658556

  14. Decontamination Data - Blister Agents

    Data.gov (United States)

    U.S. Environmental Protection Agency — Decontamination efficacy data for blister agents on various building materials using various decontamination solutions This dataset is associated with the following...

  15. Combining QSAR Modeling and Text-Mining Techniques to Link Chemical Structures and Carcinogenic Modes of Action

    Science.gov (United States)

    Papamokos, George; Silins, Ilona

    2016-01-01

    There is an increasing need for new reliable non-animal based methods to predict and test toxicity of chemicals. Quantitative structure-activity relationship (QSAR), a computer-based method linking chemical structures with biological activities, is used in predictive toxicology. In this study, we tested the approach to combine QSAR data with literature profiles of carcinogenic modes of action automatically generated by a text-mining tool. The aim was to generate data patterns to identify associations between chemical structures and biological mechanisms related to carcinogenesis. Using these two methods, individually and combined, we evaluated 96 rat carcinogens of the hematopoietic system, liver, lung, and skin. We found that skin and lung rat carcinogens were mainly mutagenic, while the group of carcinogens affecting the hematopoietic system and the liver also included a large proportion of non-mutagens. The automatic literature analysis showed that mutagenicity was a frequently reported endpoint in the literature of these carcinogens, however, less common endpoints such as immunosuppression and hormonal receptor-mediated effects were also found in connection with some of the carcinogens, results of potential importance for certain target organs. The combined approach, using QSAR and text-mining techniques, could be useful for identifying more detailed information on biological mechanisms and the relation with chemical structures. The method can be particularly useful in increasing the understanding of structure and activity relationships for non-mutagens. PMID:27625608

  16. Production of thymine glycols in DNA by radiation and chemical carcinogens as detected by a monoclonal antibody.

    Science.gov (United States)

    Leadon, S A

    1987-06-01

    In order to understand the role in carcinogenesis of damage indirectly induced by chemical carcinogens, it is important to identify the primary DNA lesions. We have measured the formation and repair of one type of DNA modification, 5,6-dihydroxydihydrothymine (thymine glycol), following exposure of cultured human cells to the carcinogens N-hydroxy-2-naphthylamine or benzo(a)pyrene. The efficiency of production of thymine glycols in DNA by these carcinogens was compared to that by ionizing radiation and ultraviolet light. Thymine glycols were detected using a monoclonal antibody against this product in a sensitive immunoassay. We found that thymine glycols were produced in DNA in a dose dependent manner after exposure to the carcinogens and that their production was reduced if either catalase or superoxide dismutase or both were present at the time of treatment. The efficiency of thymine glycol production following exposure to the chemical carcinogens was greater than that following equi-toxic doses of radiation. Thymine glycols were efficiently removed from the DNA of human cells following treatment with either the chemical carcinogens, ionizing radiation or ultraviolet light. PMID:3477281

  17. Detection of strand breaks in phiX 174 RFI and PM2 DNA reacted with ultimate and proximate carcinogens.

    Science.gov (United States)

    Thielmann, H W

    1977-10-01

    Supercoiled DNA duplexes of phages phiX 174 and PM2 were treated in aqueous solution at neutral pH with ultimate and proximate carcinogens. Subsequently, the carcinogen-treated phage DNAs were subjected to velocity sedimentation in neutral and alkaline sucrose to quantitative introduction of single strand breaks. Reaction of phage DNA with the ultimate carcinogens N-methyl-N-nitrosourea (MeNOUr), N-ethyl-N-nitrosourea (EtNOUr), 7-bromomethyl-benza[a]-anthracene, N-acetoxy-2-acetylaminofluorene [(Ac)2ONFln] and K-region oxides for short periods followed by sedimentation in neutral sucrose gradients led to very few breaks. Incubation with the proximate carcinogens N-hydroxy-2-acetylaminofluorene, 2-acetylaminofluorene, 7-methyl-, and 7,12-dimethyl-benza[a]anthracene did not result in breaks. However, when the phage DNAs were reacted with the ultimate carcinogens under the same conditions but subsequently alkali-denatured and sedimented in alkaline sucrose gradients, single strand breaks were readily introduced. Incubation with the proximate carcinogens followed by alkali denaturation and sedimentation in alkaline sucrose showed that only 7,12-dimethyl-benz[a]anthracene and, to a minor extent, 7-methyl-benz[]anthracene caused alkali-inducible breaks. The ability of N-methyl-N'-nitro-N-nitrosoguanidine to effect breakdown of superhelical phage DNA in alkali was found enhanced in the presence of N-acetyl-cysteine. PMID:145749

  18. Combining QSAR Modeling and Text-Mining Techniques to Link Chemical Structures and Carcinogenic Modes of Action.

    Science.gov (United States)

    Papamokos, George; Silins, Ilona

    2016-01-01

    There is an increasing need for new reliable non-animal based methods to predict and test toxicity of chemicals. Quantitative structure-activity relationship (QSAR), a computer-based method linking chemical structures with biological activities, is used in predictive toxicology. In this study, we tested the approach to combine QSAR data with literature profiles of carcinogenic modes of action automatically generated by a text-mining tool. The aim was to generate data patterns to identify associations between chemical structures and biological mechanisms related to carcinogenesis. Using these two methods, individually and combined, we evaluated 96 rat carcinogens of the hematopoietic system, liver, lung, and skin. We found that skin and lung rat carcinogens were mainly mutagenic, while the group of carcinogens affecting the hematopoietic system and the liver also included a large proportion of non-mutagens. The automatic literature analysis showed that mutagenicity was a frequently reported endpoint in the literature of these carcinogens, however, less common endpoints such as immunosuppression and hormonal receptor-mediated effects were also found in connection with some of the carcinogens, results of potential importance for certain target organs. The combined approach, using QSAR and text-mining techniques, could be useful for identifying more detailed information on biological mechanisms and the relation with chemical structures. The method can be particularly useful in increasing the understanding of structure and activity relationships for non-mutagens. PMID:27625608

  19. Effects of dietary fish oil on the depletion of carcinogenic PAH-DNA adduct levels in the liver of B6C3F1 mouse.

    Directory of Open Access Journals (Sweden)

    Guo-Dong Zhou

    Full Text Available Many carcinogenic polycyclic aromatic hydrocarbons (PAHs and their metabolites can bind covalently to DNA. Carcinogen-DNA adducts may lead to mutations in critical genes, eventually leading to cancer. In this study we report that fish oil (FO blocks the formation of DNA adducts by detoxification of PAHs. B6C3F1 male mice were fed a FO or corn oil (CO diet for 30 days. The animals were then treated with seven carcinogenic PAHs including benzo(apyrene (BaP with one of two doses via a single intraperitoneal injection. Animals were terminated at 1, 3, or 7 d after treatment. The levels of DNA adducts were analyzed by the (32P-postlabeling assay. Our results showed that the levels of total hepatic DNA adducts were significantly decreased in FO groups compared to CO groups with an exception of low PAH dose at 3 d (P = 0.067. Total adduct levels in the high dose PAH groups were 41.36±6.48 (Mean±SEM and 78.72±8.03 in 10(9 nucleotides (P = 0.011, respectively, for the FO and CO groups at 7 d. Animals treated with the low dose (2.5 fold lower PAHs displayed similar trends. Total adduct levels were 12.21±2.33 in the FO group and 24.07±1.99 in the CO group, P = 0.008. BPDE-dG adduct values at 7 d after treatment of high dose PAHs were 32.34±1.94 (CO group and 21.82±3.37 (FO group in 10(9 nucleotides with P value being 0.035. Low dose groups showed similar trends for BPDE-dG adduct in the two diet groups. FO significantly enhanced gene expression of Cyp1a1 in both the high and low dose PAH groups. Gstt1 at low dose of PAHs showed high levels in FO compared to CO groups with P values being 0.014. Histological observations indicated that FO played a hepatoprotective role during the early stages. Our results suggest that FO has a potential to be developed as a cancer chemopreventive agent.

  20. UV disinfection system for cabin air

    Science.gov (United States)

    Lim, Soojung; Blatchley, Ernest R.

    2009-10-01

    The air of indoor cabin environments is susceptible to contamination by airborne microbial pathogens. A number of air treatment processes are available for inactivation or removal of airborne pathogens; included among these processes is ultraviolet (UV) irradiation. The effectiveness of UV-based processes is known to be determined by the combined effects of UV dose delivery by the reactor and the UV dose-response behavior of the target microbe(s). To date, most UV system designs for air treatment have been based on empirical approaches, often involving crude representations of dose delivery and dose-response behavior. The objective of this research was to illustrate the development of a UV system for disinfection of cabin air based on well-defined methods of reactor and reaction characterization. UV dose-response behavior of a test microorganism was measured using a laboratory (bench-scale) system. Target microorganisms (bacterial spores) were first applied to membrane filters at sub-monolayer coverage. The filters were then transferred to a humidity chamber at fixed relative humidity (RH) and allowed to equilibrate with their surroundings. Microorganisms were then subjected to UV exposure under a collimated beam. The experiment was repeated at RH values ranging from 20% to 100%. UV dose-response behavior was observed to vary with RH. For example, at 100% RH, a UV dose of 20 mJ/cm 2 accomplished 99.7% (2.5 log10 U) of the Bacillus subtilis spore inactivation, whereas 99.94% (3.2 log10 U) inactivation was accomplished at this same UV dose under 20% RH conditions. To determine reactor behavior, UV dose-response behavior was combined with simulated results of computational fluid dynamics (CFD) and radiation intensity field models. This modeling approach allowed estimating the UV dose distribution delivered by the reactor. The advantage of this approach is that simulation of many reactor configurations can be done in a relatively short period of time. Moreover, by

  1. UV-Induced DNA Damage Promotes Resistance to the Biotrophic Pathogen Hyaloperonospora parasitica in Arabidopsis1[C][OA

    Science.gov (United States)

    Kunz, Bernard A.; Dando, Paige K.; Grice, Desma M.; Mohr, Peter G.; Schenk, Peer M.; Cahill, David M.

    2008-01-01

    Plant innate immunity to pathogenic microorganisms is activated in response to recognition of extracellular or intracellular pathogen molecules by transmembrane receptors or resistance proteins, respectively. The defense signaling pathways share components with those involved in plant responses to UV radiation, which can induce expression of plant genes important for pathogen resistance. Such intriguing links suggest that UV treatment might activate resistance to pathogens in normally susceptible host plants. Here, we demonstrate that pre-inoculative UV (254 nm) irradiation of Arabidopsis (Arabidopsis thaliana) susceptible to infection by the biotrophic oomycete Hyaloperonospora parasitica, the causative agent of downy mildew, induces dose- and time-dependent resistance to the pathogen detectable up to 7 d after UV exposure. Limiting repair of UV photoproducts by postirradiation incubation in the dark, or mutational inactivation of cyclobutane pyrimidine dimer photolyase, (6-4) photoproduct photolyase, or nucleotide excision repair increased the magnitude of UV-induced pathogen resistance. In the absence of treatment with 254-nm UV, plant nucleotide excision repair mutants also defective for cyclobutane pyrimidine dimer or (6-4) photoproduct photolyase displayed resistance to H. parasitica, partially attributable to short wavelength UV-B (280–320 nm) radiation emitted by incubator lights. These results indicate UV irradiation can initiate the development of resistance to H. parasitica in plants normally susceptible to the pathogen and point to a key role for UV-induced DNA damage. They also suggest UV treatment can circumvent the requirement for recognition of H. parasitica molecules by Arabidopsis proteins to activate an immune response. PMID:18667719

  2. Mechanisms of UV-induced signal transduction

    Energy Technology Data Exchange (ETDEWEB)

    Kulms, D.; Schwarz, T. [Univ. Muenster, Muenster (Germany). Ludwing Boltzmann Inst. for Cell Biology and Immunobiology of the Skin

    2002-04-01

    Ultraviolet radiation (UV) causes a variety of biological effects that can be either beneficial or harmful for human health. To exert these effects on a cellular basis, UV uses a variety of signaling pathways. DNA is the major chromophore for UVB. Thus, nuclear DNA damage has been detected to be a major mediator of numerous UVB effects, and experimental reduction of DNA damage is associated with a loss of these effects. On the other hand, UV has been found to utilize molecular components within the cytoplasm or at the cell membrane for signaling. UV can directly activate cell surface receptors, kinases, and transcription factors. The nuclear and extranuclear signaling pathways are generated independently and have been recently recognized to be not mutually exclusive but to contribute to various UV effects in an independent and additive way. Further knowledge of how these signaling pathways relate to each other will certainly increase our understanding of how UV acts as a pathogen. The following review will briefly discuss current aspects of the mechanisms involved in UV-induced signal transduction. (author)

  3. Radiographic scintiscanning agent

    International Nuclear Information System (INIS)

    A new technetium-based scintiscanning agent has been prepared comprising a water soluble sup(99m)Tc-methanehydroxydiphosphonate in combination with a reducing agent selected from stannous, ferrous, chromous and titanous salts. As an additional stabilizer salts and esters of gentisic or ascorbic acids have been used. (E.G.)

  4. Agent Development Toolkits

    CERN Document Server

    Singh, Aarti; Sharma, A K

    2011-01-01

    Development of agents as well as their wide usage requires good underlying infrastructure. Literature indicates scarcity of agent development tools in initial years of research which limited the exploitation of this beneficial technology. However, today a wide variety of tools are available, for developing robust infrastructure. This technical note provides a deep overview of such tools and contrasts features provided by them.

  5. Reactivation of DNA replication of the parvovirus MVM in UV preirradiated mouse cells

    International Nuclear Information System (INIS)

    The parvovirus Minute-Virus-of-Mice (MVM) was used to probe the DNA replication activities expressed by mouse fibroblasts. This system allowed us to study quantitatively the effect of UV-induced DNA lesions on the progression of DNA replication in vivo. MVM was UV-irradiated prior to infection. Pyrimidine dimers induced in the viral genome account for the reduced level of intracellular viral DNA synthesis, assuming that most of these lesions block viral DNA replication in unirradiated cells. The inhibition of damaged MVM DNA synthesis is less severe if the host cells themselves are irradiated prior to virus infection. This stimulation of viral DNA replication in pretreated cells might account for the UV-enhanced viral reactivation phenomenon, i.e. the increased survival of nuclear-replicating viruses propagated in cells preexposed to various genotoxic agents

  6. UV curing silicon-containing epoxy resin and its glass cloth reinforced composites

    International Nuclear Information System (INIS)

    A UV-curable cationic silicon-containing epoxy resin formulation was developed. The gel conversion of the cured resin after 10-min UV irradiation reached 80% in the presence of 5% diaryliodonium salt photoinitiator and 5.5% polyol chain transfer agent by cationic ring-opening polymerization. The glass cloth-reinforced composites were fabricated with the silicon-containing epoxy resin using the wet lay-up technique and UV irradiation. The mechanical properties of the composites were evaluated. Compared with glass cloth reinforced bisphenol A epoxy resin matrix composites, the silicon-containing epoxy resin matrix composites possessed higher tensile strength and interlayer shear strength which was 158.5MPa and 9.9MPa respectively while other mechanical properties such as flexural property and tensile modulus were similar. (authors)

  7. The UV-irradiated mouse as a model for testing biological response modifiers

    International Nuclear Information System (INIS)

    In addition to inducing primary cancers of the skin, ultraviolet (UV) radiation produces specific impairments in the immune system that contribute to the growth and pathogenesis of these skin cancers. The cellular basis for the immunological alterations induced in mice by UV radiation has been studied and characterized over the past ten years. It is now possible to make use of this system to study the activity and mode of action of biological response modifiers. The advantages of this system are that it employs primary hosts, which may respond quite differently from normal animals bearing a transplanted tumor, it closely parallels several specific situations relevant to human cancer, and it may be useful in establishing the mechanism of action of certain agents. Studies in which biological response modifiers have been used in conjunction with the UV carcinogenesis model are reviewed. (Auth.)

  8. Effect of UV irradiation on cutaneous cicatrices

    DEFF Research Database (Denmark)

    Due, Eva; Rossen, Kristian; Sorensen, Lars Tue;

    2007-01-01

    The aim of this study was to examine the effect of ultraviolet (UV) irradiation on human cutaneous cicatrices. In this randomized, controlled study, dermal punch biopsy wounds served as a wound healing model. Wounds healed by primary or second intention and were randomized to postoperative solar UV...... irradiation or to no UV exposure. Evaluations after 5 and 12 weeks included blinded clinical assessments, skin reflectance measurements, histology, immunohistochemistry, and biochemical analyses of the N-terminal propeptide from procollagen-1, hydroxyproline, hydroxylysine, and proline. Twelve weeks...

  9. UV Bandpass Optical Filter for Microspectometers

    OpenAIRE

    Correia, J. H.; Emadi, A.R.; Wolffenbuttel, R.F.

    2006-01-01

    This paper describes the design and modeling of a UV bandpass optical filter for microspectrometers. The materials used for fabricating the multilayer UV filter are: silicon dioxide (SiO2), titanium dioxide (TiO2) and yttrium oxide (Y2O3). The optical filter shows a bandpass response wavelength in the range 230-280 nm, with a transmittance higher than 80%. Such a device is extremely suitable for optical detection of biological molecules with optical absorption or/and fluorescence in the UV sp...

  10. Asimovian Adaptive Agents

    CERN Document Server

    Gordon, D F

    2011-01-01

    The goal of this research is to develop agents that are adaptive and predictable and timely. At first blush, these three requirements seem contradictory. For example, adaptation risks introducing undesirable side effects, thereby making agents' behavior less predictable. Furthermore, although formal verification can assist in ensuring behavioral predictability, it is known to be time-consuming. Our solution to the challenge of satisfying all three requirements is the following. Agents have finite-state automaton plans, which are adapted online via evolutionary learning (perturbation) operators. To ensure that critical behavioral constraints are always satisfied, agents' plans are first formally verified. They are then reverified after every adaptation. If reverification concludes that constraints are violated, the plans are repaired. The main objective of this paper is to improve the efficiency of reverification after learning, so that agents have a sufficiently rapid response time. We present two solutions: ...

  11. How do agents represent?

    Science.gov (United States)

    Ryan, Alex

    Representation is inherent to the concept of an agent, but its importance in complex systems has not yet been widely recognised. In this paper I introduce Peirce's theory of signs, which facilitates a definition of representation in general. In summary, representation means that for some agent, a model is used to stand in for another entity in a way that shapes the behaviour of the agent with respect to that entity. Representation in general is then related to the theories of representation that have developed within different disciplines. I compare theories of representation from metaphysics, military theory and systems theory. Additional complications arise in explaining the special case of mental representations, which is the focus of cognitive science. I consider the dominant theory of cognition — that the brain is a representational device — as well as the sceptical anti-representational response. Finally, I argue that representation distinguishes agents from non-representational objects: agents are objects capable of representation.

  12. Predicting the hepatocarcinogenic potential of alkenylbenzene flavoring agents using toxicogenomics and machine learning

    International Nuclear Information System (INIS)

    Identification of carcinogenic activity is the primary goal of the 2-year bioassay. The expense of these studies limits the number of chemicals that can be studied and therefore chemicals need to be prioritized based on a variety of parameters. We have developed an ensemble of support vector machine classification models based on male F344 rat liver gene expression following 2, 14 or 90 days of exposure to a collection of hepatocarcinogens (aflatoxin B1, 1-amino-2,4-dibromoanthraquinone, N-nitrosodimethylamine, methyleugenol) and non-hepatocarcinogens (acetaminophen, ascorbic acid, tryptophan). Seven models were generated based on individual exposure durations (2, 14 or 90 days) or a combination of exposures (2 + 14, 2 + 90, 14 + 90 and 2 + 14 + 90 days). All sets of data, with the exception of one yielded models with 0% cross-validation error. Independent validation of the models was performed using expression data from the liver of rats exposed at 2 dose levels to a collection of alkenylbenzene flavoring agents. Depending on the model used and the exposure duration of the test data, independent validation error rates ranged from 47% to 10%. The variable with the most notable effect on independent validation accuracy was exposure duration of the alkenylbenzene test data. All models generally exhibited improved performance as the exposure duration of the alkenylbenzene data increased. The models differentiated between hepatocarcinogenic (estragole and safrole) and non-hepatocarcinogenic (anethole, eugenol and isoeugenol) alkenylbenzenes previously studied in a carcinogenicity bioassay. In the case of safrole the models correctly differentiated between carcinogenic and non-carcinogenic dose levels. The models predict that two alkenylbenzenes not previously assessed in a carcinogenicity bioassay, myristicin and isosafrole, would be weakly hepatocarcinogenic if studied at a dose level of 2 mmol/kg bw/day for 2 years in male F344 rats; therefore suggesting that these

  13. Prediction of rodent carcinogenic potential of naturally occurring chemicals in the human diet using high-throughput QSAR predictive modeling

    International Nuclear Information System (INIS)

    Consistent with the U.S. Food and Drug Administration (FDA) Critical Path Initiative, predictive toxicology software programs employing quantitative structure-activity relationship (QSAR) models are currently under evaluation for regulatory risk assessment and scientific decision support for highly sensitive endpoints such as carcinogenicity, mutagenicity and reproductive toxicity. At the FDA's Center for Food Safety and Applied Nutrition's Office of Food Additive Safety and the Center for Drug Evaluation and Research's Informatics and Computational Safety Analysis Staff (ICSAS), the use of computational SAR tools for both qualitative and quantitative risk assessment applications are being developed and evaluated. One tool of current interest is MDL-QSAR predictive discriminant analysis modeling of rodent carcinogenicity, which has been previously evaluated for pharmaceutical applications by the FDA ICSAS. The study described in this paper aims to evaluate the utility of this software to estimate the carcinogenic potential of small, organic, naturally occurring chemicals found in the human diet. In addition, a group of 19 known synthetic dietary constituents that were positive in rodent carcinogenicity studies served as a control group. In the test group of naturally occurring chemicals, 101 were found to be suitable for predictive modeling using this software's discriminant analysis modeling approach. Predictions performed on these compounds were compared to published experimental evidence of each compound's carcinogenic potential. Experimental evidence included relevant toxicological studies such as rodent cancer bioassays, rodent anti-carcinogenicity studies, genotoxic studies, and the presence of chemical structural alerts. Statistical indices of predictive performance were calculated to assess the utility of the predictive modeling method. Results revealed good predictive performance using this software's rodent carcinogenicity module of over 1200 chemicals

  14. Pros and cons of letting in UV-B

    NARCIS (Netherlands)

    Hoffmann, S.

    2001-01-01

    Effect van UV-straling op de lengte van het gewas (potchrysant) en bloemkleur (pelargonium) en onderzoek naar transmissie van UV-stralen bij verschillende dakdekmaterialen (folie en glas met en zonder UV)

  15. Studies of biological effects of fluoride stannous and UV short in Escherichia coli BH110

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira da C, R., E-mail: rogercosta1@hotmail.com [Federal Institute of Education, Science and Technology of Goias, Campus Uruacu, Rua Formosa Qd 28 e 29, Loteamento Santana, 76400-000 Uruacu, Goias (Brazil)

    2015-10-15

    Full text: The amount of UV rays on the Earth's surface has increased due to depletion of the ozone layer, and this has worried society, since these radiation although not considered ionizing can cause damage to biological membrane and especially to DNA. The DNA has cell repair mechanisms that can work in lesions caused by electromagnetic radiation such as ultraviolet -short (UV C)and agents causing oxidative stress, such as tin salts. Among the repair mechanisms can highlight the adaptive repair, which consists of smaller doses to cells pre-exposure of an oxidizing agent, and when these cells are exposed to larger doses of the agent even if there is a reduction in mortality rate which leads to complete that repair mechanisms are activated in the pre-exposure reducing cell mortality. Several publications have shown the genotoxic effects of stannous salts such as stannous fluoride (SnF{sub 2}), which shows the importance of the study, since these salts are widely used in industry as components in toothpastes and mouthwashes. So we check whether pretreatment with UV C is able to induce adaptive response reducing the cytotoxic effects caused by exposure of the strains to SnF{sub 2}. We use a strain of Escherichia coli BH110 (BH110 E. coli) deficient in three genes (fpg, nfo and xth) involved in the excision repair bases. To verify the induction of adaptive response to strain BH110 was exposed to various doses of UV C and then treated with SnF{sub 2} a concentration of 110 u M. Our results showed that the LD10 of strain BH110 is 20 J/m{sup 2} and pre-treatment with UV C does not seem to induce adaptive repair in BH110 strains. (Author)

  16. Studies of biological effects of fluoride stannous and UV short in Escherichia coli BH110

    International Nuclear Information System (INIS)

    Full text: The amount of UV rays on the Earth's surface has increased due to depletion of the ozone layer, and this has worried society, since these radiation although not considered ionizing can cause damage to biological membrane and especially to DNA. The DNA has cell repair mechanisms that can work in lesions caused by electromagnetic radiation such as ultraviolet -short (UV C)and agents causing oxidative stress, such as tin salts. Among the repair mechanisms can highlight the adaptive repair, which consists of smaller doses to cells pre-exposure of an oxidizing agent, and when these cells are exposed to larger doses of the agent even if there is a reduction in mortality rate which leads to complete that repair mechanisms are activated in the pre-exposure reducing cell mortality. Several publications have shown the genotoxic effects of stannous salts such as stannous fluoride (SnF2), which shows the importance of the study, since these salts are widely used in industry as components in toothpastes and mouthwashes. So we check whether pretreatment with UV C is able to induce adaptive response reducing the cytotoxic effects caused by exposure of the strains to SnF2. We use a strain of Escherichia coli BH110 (BH110 E. coli) deficient in three genes (fpg, nfo and xth) involved in the excision repair bases. To verify the induction of adaptive response to strain BH110 was exposed to various doses of UV C and then treated with SnF2 a concentration of 110 u M. Our results showed that the LD10 of strain BH110 is 20 J/m2 and pre-treatment with UV C does not seem to induce adaptive repair in BH110 strains. (Author)

  17. Transformation of UV-hypersensitive Chinese hamster ovary cell mutants with UV-irradiated plasmids

    International Nuclear Information System (INIS)

    Transfection of UV-hypersensitive, DNA repair-deficient Chinese hamster ovary (CHO) cell lines and parental, repair-proficient CHO cells with UV-irradiated pHaprt-1 or pSV2gpt plasmids resulted in different responses by recipient cell lines to UV damage in transfected DNA. Unlike results reported for human cells, UV irradiation of transfecting DNA did not stimulate genetic transformation of CHO recipient cells. In repair-deficient CHO cells, proportionally fewer transformants were produced with increasing UV damage than in repair-proficient cells in transfections with UV-irradiated hamster adenine phosphoribosyltransferase (APRT) gene contained in plasmid pHaprt-1. Transfection of CHO cells with UV-irradiated pSV2gpt resulted in neither decline in transformation frequencies in repair-deficient cell lines relative to repair-proficient cells nor stimulation of genetic transformation by UV damage in the plasmid. Blot hybridization analysis of DNA samples isolated from transformed cells showed no dramatic changes in copy number or arrangement of transfected plasmid DNA with increasing UV dose. The authors conclude responses of recipient cells to UV-damaged transfecting plasmids depend on type of recipient cell and characteristics of the genetic sequence used for transfection. (author)

  18. Interaction of anti-adhesive silicone films with UV embossing resin

    International Nuclear Information System (INIS)

    The durability of two silicone films, which were formed from silicone-based release agents with different molecular weights (MW), as anti-adhesive coatings for molds used for UV embossing was investigated. Flat electroless nickel-plated polyester stamp and UV-curable polyethylene glycol diacrylate (PEGDA) were the mold and molding material, respectively. The surface chemical composition of the silicone films and the PEGDA moldings was analyzed by X-ray photoelectron spectroscopy (XPS) as a function of molding times using the same nickelized polyester stamp. Silicone transfer was found to occur from the silicone films to the moldings with increased number of moldings. The silicone film formed from the release agent with the higher MW had the poorer durability. Two mechanisms are proposed for the material transfer

  19. Synthesis and Performance of a Biomimetic Indicator for Alkylating Agents.

    Science.gov (United States)

    Provencher, Philip A; Love, Jennifer A

    2015-10-01

    4-(4-Nitrobenzyl)pyridine (NBP) is a colorimetric indicator compound for many types of carcinogenic alkylating agents. Because of the similar reactivity of NBP and guanine in DNA, NBP serves as a DNA model. NBP assays are used in the toxicological screening of pharmaceutical compounds, detection of chemical warfare agents, environmental hygiene technology, preliminary toxicology tests, mutagenicity of medicinal compounds, and other chemical analyses. Nevertheless, the use of NBP as a DNA model suffers from the compound's low water solubility, its lack of reactive oxygen sites, and dissimilar steric encumbrance compared to DNA. We report herein the design and synthesis of NBP derivatives that address some of these issues. These derivatives have been tested in solution and found to be superior in the colorimetric assay of the alkylating anticancer drug cyclophosphamide. The derivatives have also been integrated into a polymeric silica material which changes color upon the exposure to dangerous alkylating agents, such as iodomethane vapor, without the need for an exogenous base. This material modernizes the NBP assay from a time-consuming laboratory analysis to a real-time solid state sensor, which requires neither solvent nor additional reagents and can detect both gas- and solution-phase alkylating agents.

  20. Cellular distribution of cell cycle-related molecules in the renal tubules of rats treated with renal carcinogens for 28 days: relationship between cell cycle aberration and carcinogenesis.

    Science.gov (United States)

    Taniai, Eriko; Hayashi, Hitomi; Yafune, Atsunori; Watanabe, Maiko; Akane, Hirotoshi; Suzuki, Kazuhiko; Mitsumori, Kunitoshi; Shibutani, Makoto

    2012-09-01

    Some renal carcinogens can induce karyomegaly, which reflects aberrant cell division in the renal tubules, from the early stages of exposure. To clarify the cell cycle-related changes during the early stages of renal carcinogenesis, we performed immunohistochemical analysis of tubular cells in male F344 rats treated with carcinogenic doses of representative renal carcinogens for 28 days. For this purpose, the karyomegaly-inducing carcinogens ochratoxin A (OTA), ferric nitrilotriacetic acid, and monuron, and the non-karyomegaly-inducing carcinogens tris(2-chloroethyl) phosphate and potassium bromate were examined. For comparison, a karyomegaly-inducing non-carcinogen, p-nitrobenzoic acid, and a non-carcinogenic non-karyomegaly-inducing renal toxicant, acetaminophen, were also examined. The outer stripe of the outer medulla (OSOM) and the cortex + OSOM were subjected to morphometric analysis of immunoreactive proximal tubular cells. Renal carcinogens, irrespective of their karyomegaly-inducing potential, increased proximal tubular cell proliferation accompanied by an increase in topoisomerase IIα-immunoreactive cells, suggesting a reflection of cell proliferation. Karyomegaly-inducing carcinogens increased nuclear Cdc2-, γH2AX-, and phosphorylated Chk2-immunoreactive cells in both areas, the former two acting in response to DNA damage and the latter one suggestive of sustained G₂. OTA, an OSOM-targeting carcinogen, could easily be distinguished from untreated controls and non-carcinogens by evaluation of molecules responding to DNA damage and G₂/M transition in the OSOM. Thus, all renal carcinogens examined facilitated proximal tubular proliferation by repeated short-term treatment. Among these, karyomegaly-inducing carcinogens may cause DNA damage and G₂ arrest in the target tubular cells.

  1. Monitoring of occupational exposure to cytostatic anticancer agents.

    Science.gov (United States)

    Sorsa, M; Anderson, D

    1996-08-17

    Many anticancer agents have been shown to be carcinogenic, mutagenic and teratogenic in experimental animals and in in vitro test systems. Epidemiological data on the association of second neoplasms with a specific chemotherapy treatment is available on some 30 agents, and in the case of 10 compounds the overall evidence on human carcinogenicity has been evaluated to be conclusive (Group 1: IARC, 1987 and 1990). The primary source of human exposure to anticancer drugs is from their use in therapy of cancer. However, persons employed in the manufacture, preparation and administration of the drugs to patients and in nursing patients may also be exposed. Safe handling of anticancer drugs, since the introduction of various general handling guidelines, is now good practice in hospitals, pharmacies and drug manufacturing companies of most developed countries. Careless handling of cancer chemotherapeutic agents may lead to exposure of the personnel in amounts detectable with chemical or biological methods in the body fluids or cell samples of the subjects. The exposure is typically to mixed compounds over long-term and to low exposure levels with accidental peaks. Therefore, the use of biological exposure markers is appropriate for the monitoring of such exposure patterns. The biological markers/methods for exposure assessment are either non-specific (e.g., cytogenetic damage, point mutations or 32P-post-labelling adducts in peripheral blood lymphocytes, urinary mutagenicity) or specific for a given compound (immunological methods for DNA adducts, specific analytical methods). Studies have revealed minor amounts of cyclophosphamide in the urine of pharmacy technicians and nurses handling the drug even when taking special safety precautions (Sessink et al. (1994a) J. Occup. Med., 36, 79; Sessink et al. (1994b) Arch. Env. Health, 49, 165). Another study showed surface wipe samples with measurable cyclophosphamide even away from the handling site (McDevitt et al. (1993) J

  2. The function and significance of SELENBP1 downregulation in human bronchial epithelial carcinogenic process.

    Directory of Open Access Journals (Sweden)

    Gu-Qing Zeng

    Full Text Available BACKGROUND: Our quantitative proteomic study showed that selenium-binding protein 1 (SELENBP1 was progressively decreased in human bronchial epithelial carcinogenic process. However, there is little information on expression and function of SELENBP1 during human lung squamous cell cancer (LSCC carcinogenesis. METHODS: iTRAQ-tagging combined with 2D LC-MS/MS analysis was used to identify differentially expressed proteins in the human bronchial epithelial carcinogenic process. SELENBP1, member of selenoproteins family and progressively downregulated in this process, was selected to further study. Both Western blotting and immunohistochemistry were performed to detect SELENBP1 expression in independent sets of tissues of bronchial epithelial carcinogenesis, and ability of SELENBP1 for discriminating NBE (normal bronchial epithelium from preneoplastic lesions from invasive LSCC was evaluated. The effects of SELENBP1 downregulation on the susceptibility of benzo(apyrene (B[a]P-induced human bronchial epithelial cell transformation were determined. RESULTS: 102 differentially expressed proteins were identified by quantitative proteomics, and SELENBP1 was found and confirmed being progressively decreased in the human bronchial epithelial carcinogenic process. The sensitivity and specificity of SELENBP1 were 80% and 79% in discriminating NBE from preneoplastic lesions, 79% and 82% in discriminating NBE from invasive LSCC, and 77% and 71% in discriminating preneoplastic lesions from invasive LSCC, respectively. Furthermore, knockdown of SELENBP1 in immortalized human bronchial epithelial cell line 16HBE cells significantly increased the efficiency of B[a]P-induced cell transformation. CONCLUSIONS: The present data shows for the first time that decreased SELENBP1 is an early event in LSCC, increases B[a]P-induced human bronchial epithelial cell transformation, and might serve as a novel potential biomarker for early detection of LSCC.

  3. Genotoxic and carcinogenic risks associated with the dietary consumption of repeatedly heated coconut oil.

    Science.gov (United States)

    Srivastava, Smita; Singh, Madhulika; George, Jasmine; Bhui, Kulpreet; Murari Saxena, Anand; Shukla, Yogeshwer

    2010-11-01

    Repeated heating of vegetable oils at high temperatures during cooking is a very common cooking practice. Repeated heating of edible oils can generate a number of compounds, including polycyclic aromatic hydrocarbons (PAH), some of which have been reported to have carcinogenic potential. Consumption of these repeatedly heated oils can pose a serious health hazard. The objectives of the present study were to evaluate the genotoxic and carcinogenic risks associated with the consumption of repeatedly heated coconut oil (RCO), which is one of the commonly consumed cooking and frying medium. The PAH were analysed using HPLC in fresh CO, single-heated CO (SCO) and RCO. Results revealed the presence of certain PAH, known to possess carcinogenic potential, in RCO when compared with SCO. Oral intake of RCO in Wistar rats resulted in a significant induction of aberrant cells (P<0·05) and micronuclei (P<0·05) in a dose-dependent manner. Oxidative stress analysis showed a significant (P<0·05) decrease in the levels of antioxidant enzymes such as superoxide dismutase and catalase with a concurrent increase in reactive oxygen species and lipid peroxidation in the liver. In addition, RCO given alone and along with diethylnitrosamine for 12 weeks induced altered hepatic foci as noticed by alteration in positive (γ-glutamyl transpeptidase and glutathione-S-transferase) and negative (adenosine triphosphatase, alkaline phosphatase and glucose-6-phosphatase) hepatospecific biomarkers. A significant decrease in the relative and absolute hepatic weight of RCO-supplemented rats was recorded (P<0·05). In conclusion, dietary consumption of RCO can cause a genotoxic and preneoplastic change in the liver.

  4. Dietary fish oil blocks carcinogen-induced down-regulation of colonic protein kinase C isozymes.

    Science.gov (United States)

    Jiang, Y H; Lupton, J R; Chapkin, R S

    1997-02-01

    In order to elucidate the influence of dietary constituents on colonic intracellular signal transduction, the effect of different fats on rat colonic epithelial protein kinase C (PKC) alpha (classical), delta (novel) and lambda-zeta (atypical) expression was determined in carcinogen-treated animals. Sprague-Dawley rats were provided with one of two fats (corn oil and fish oil); plus or minus the carcinogen azoxymethane (AOM) and killed at two time points (15 and 37 weeks) in a 2x2x2 factorial design. At 5 and 6 weeks of age, animals were injected s.c. with either AOM at a dose of 15 mg/kg body weight or saline once a week for 2 weeks and continued on the same diet until termination of the study. At 15 and 37 weeks after the second injection, 10 rats from each treatment group were killed. Colonic PKC alpha, delta and lambda-zeta steady-state protein and mRNA levels were determined using immunoblotting and relative quantitative polymerase chain reaction, respectively. Colonic mucosa from rats injected with AOM had significantly suppressed membrane and cytosolic PKC alpha and cytosolic lambda-zeta protein levels (P fish oil diets had significantly higher (P protein levels relative to animals fed corn oil diets. However, the effect of diet and AOM on the steady-state expression of PKC alpha, delta and zeta mRNA was not consistent with changes in the respective isozyme protein levels, suggesting regulation at the post-transcriptional level. These data demonstrate that dietary fish oil blocks the carcinogen-induced decrease in the steady-state levels of colonic mucosal PKC delta and lambda-zeta, which may in part explain why this fat source protects against colon cancer development.

  5. Prediction of Non-Genotoxic Carcinogenicity Based on Genetic Profiles of Short Term Exposure Assays

    Science.gov (United States)

    Pérez, Luis Orlando; González-José, Rolando; García, Pilar Peral

    2016-01-01

    Non-genotoxic carcinogens are substances that induce tumorigenesis by non-mutagenic mechanisms and long term rodent bioassays are required to identify them. Recent studies have shown that transcription profiling can be applied to develop early identifiers for long term phenotypes. In this study, we used rat liver expression profiles from the NTP (National Toxicology Program, Research Triangle Park, USA) DrugMatrix Database to construct a gene classifier that can distinguish between non-genotoxic carcinogens and other chemicals. The model was based on short term exposure assays (3 days) and the training was limited to oxidative stressors, peroxisome proliferators and hormone modulators. Validation of the predictor was performed on independent toxicogenomic data (TG-GATEs, Toxicogenomics Project-Genomics Assisted Toxicity Evaluation System, Osaka, Japan). To build our model we performed Random Forests together with a recursive elimination algorithm (VarSelRF). Gene set enrichment analysis was employed for functional interpretation. A total of 770 microarrays comprising 96 different compounds were analyzed and a predictor of 54 genes was built. Prediction accuracy was 0.85 in the training set, 0.87 in the test set and increased with increasing concentration in the validation set: 0.6 at low dose, 0.7 at medium doses and 0.81 at high doses. Pathway analysis revealed gene prominence of cellular respiration, energy production and lipoprotein metabolism. The biggest target of toxicogenomics is accurately predict the toxicity of unknown drugs. In this analysis, we presented a classifier that can predict non-genotoxic carcinogenicity by using short term exposure assays. In this approach, dose level is critical when evaluating chemicals at early time points.

  6. Investigation of UV photocurable microcapsule inner crosslink extent

    Science.gov (United States)

    Li, Xiaowei; Meng, Shuangshuang; Lai, Weidong; Yu, Haiyang; Fu, Guangsheng

    2008-11-01

    UV photocuring technology has encountered increased applications in recent years, which finds a variety of applications on protective coating of the optical-fiber, ink and optical recording materials. Combined with techniques of photohardenable, microcapsule, heat-sensitive and interface-polymerization method, a novel photoheat sensitive recording material of non-silver salt is explored in this thesis. Microcapsules are particulate substance with a core and shell structure, where photopolymerizable composition, monofunctional/polyfunctional diluents, photopolymerization initiator, photosensitivity enhancing agent and dye precursor are encapsulated as the internal phase. In this paper introduced the characteristics and curing mechanism of photo-sensitive microcapsule materials. The photocuring process may be a complex-function with photopolymerizable compound and photopolymerization initiator. For the sake of high photocuring speed and degree, optimal photo-sensitive materials were selected. In order to match with the light source excitation wavelength and absorb more wider ultraviolet band, combined type of photo-polymerization initiators were employed. With the kinds and dosage of photopolymerization initiator changing, the photocuring speed and quality can be ameliorated. Through studying the UV-visible absorption spectrum and infra-red spectrum of the material , the optical response property of the inner compound can be obtained.

  7. New technology and application in UV curing

    International Nuclear Information System (INIS)

    Overview of radcure technology was presented. Its included this following subjects, radiation curable powder coatings, UV curable water based polyurethanes, photo-initiators, fire retardancy, aqueous systems, cationic, ceramic and optical grade material

  8. Remote UV Fluorescence Lifetime Spectrometer Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The goal of this project is to develop, demonstrate, and deliver to NASA an innovative, portable, and power efficient Remote UV Fluorescence Lifetime Spectrometer...

  9. ZnO UV Detectors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Radiation-hard UV detectors will be developed with ZnO in Phase I efforts by MOXtronics, Inc. (MOX). ZnO is a very suitable material for fabrication of high-speed,...

  10. High index contrast UV-written waveguides

    DEFF Research Database (Denmark)

    Svalgaard, Mikael; Færch, Kjartan Ullitz

    By increasing the concentration of molecular hydrogen in germanosilica samples, we show that buried channel waveguides with an index step of up to 0.02 can be fabricated using the directUV writing technique....

  11. UV curable palm oil based inks

    International Nuclear Information System (INIS)

    UV curable inks are useful for their instant drying, energy saving and high productivity properties. The basic materials for formulating UV curable inks consist of prepolymer, monomers, photoinitiators, pigments and other additives. The percentage composition and ingredients depend very much on the types of inks to be produced. Palm oil is one of the main raw materials available in the country. Hence, the diversification of palm oil derivatives into new products has been given priority. The current focus of the present work is to evaluate the use of palm oil based urethane acrylate (POBUA) as a prepolymer in the UV inks system. A study was conducted on the use of POBUA with other materials in ink formulation. These include the types and concentration of photoinitiators, monomers and commercial urethane acrylates. The evaluation of the ink properties such as curing, adhesion, color density have been carried out. It was found that POBUA could be introduced in the UV ink system. (Author)

  12. UV curable palm oil based ink

    International Nuclear Information System (INIS)

    UV curable inks are useful for their instant drying, energy saving and high productivity properties. The basic materials for formulating UV curable inks consist of prepolymer, monomers, photoinitiators, pigments and other additives. The percentage composition and ingredients depend very much on the types of inks to be produced. Palm oil is one of the main raw materials available in the country. Hence, the diversification of palm oil derivatives into new products has been given priority. The current focus of the present work is to evaluate the use of palm oil urethane acrylate (POBUA) as a prepolymer in the UV ink system. A study was conducted on the use of POBUA with other materials in ink formulation. These include the types and concentration of photoinitiators, monomers and commercial urethane acrylates. The evaluation of the ink properties such as curing, adhesion, color density have been carried out. It was found that POBUA could be introduced in the UV ink system. (Author)

  13. Mean Annual UV-B Irradiance

    Data.gov (United States)

    U.S. Environmental Protection Agency — Ultraviolet-B (UV-B) radiation is the most energetic part of sunlight reaching the Earth's surface (wavelength region is 280 to 315 nm), and it has been shown to...

  14. Metabolic dephenylation of the rubber antioxidant N-phenyl-2-naphthylamine to carcinogenic 2-naphthylamine in rats.

    Science.gov (United States)

    Weiss, Tobias; Bolt, Hermann M; Schlüter, Gerhard; Koslitz, Stephan; Taeger, Dirk; Welge, Peter; Brüning, Thomas

    2013-07-01

    N-Phenyl-2-naphthylamine (P2NA) was widely used as oxidation inhibitor, particularly in rubber manufacturing. Technical-grade P2NA was contaminated with carcinogenic 2-naphthylamine (2NA), and bladder cancer risk in exposed workers was attributed to this impurity. Investigations in humans and mammalian species revealed that small amounts of 2NA are excreted into urine after exposure to P2NA. However, since 2NA per se is not carcinogenic and main downstream metabolites of 2NA have not been found in urine so far, it remained uncertain if 2NA derived from P2NA dephenylation is further activated to carcinogenic downstream metabolites. An experimental animal study was therefore designed to indicate if, and if yes to which extent, 2NA from P2NA dephenylation is accessible to the metabolic pathway that is held responsible for the carcinogenicity of 2NA. Groups of 5 male and female CD rats were dosed with P2NA (2-550 mg/kg b.w.) and 2NA (0.075-75 mg/kg b.w.); 2NA-haemoglobin adducts and urinary 2NA excretion were determined applying GC-MS/MS. 2NA haemoglobin adducts originated dose-dependently after 2NA and P2NA dosing. To induce identical adduct concentrations, an approximately 100-200-fold higher dose of P2NA was necessary compared to 2NA. Since haemoglobin adducts are formed by the same pathway (N-hydroxylation) as the ultimate carcinogens from 2NA, the comparison of adduct concentrations after 2NA and P2NA dosage permits a quantitative estimate of the carcinogenicity of P2NA. The results show that 2NA derived from dephenylation of P2NA enters the carcinogenic downstream pathway of 2NA in rats. Hence, the bladder cancer risk after human exposures to P2NA must be re-evaluated. PMID:23423714

  15. Biological warfare agents

    Directory of Open Access Journals (Sweden)

    Duraipandian Thavaselvam

    2010-01-01

    Full Text Available The recent bioterrorist attacks using anthrax spores have emphasized the need to detect and decontaminate critical facilities in the shortest possible time. There has been a remarkable progress in the detection, protection and decontamination of biological warfare agents as many instrumentation platforms and detection methodologies are developed and commissioned. Even then the threat of biological warfare agents and their use in bioterrorist attacks still remain a leading cause of global concern. Furthermore in the past decade there have been threats due to the emerging new diseases and also the re-emergence of old diseases and development of antimicrobial resistance and spread to new geographical regions. The preparedness against these agents need complete knowledge about the disease, better research and training facilities, diagnostic facilities and improved public health system. This review on the biological warfare agents will provide information on the biological warfare agents, their mode of transmission and spread and also the detection systems available to detect them. In addition the current information on the availability of commercially available and developing technologies against biological warfare agents has also been discussed. The risk that arise due to the use of these agents in warfare or bioterrorism related scenario can be mitigated with the availability of improved detection technologies.

  16. Carcinogenic Air Toxics Exposure and Their Cancer-Related Health Impacts in the United States

    Science.gov (United States)

    Zhou, Ying; Li, Chaoyang; Huijbregts, Mark A. J.; Mumtaz, M. Moiz

    2015-01-01

    Public health protection from air pollution can be achieved more effectively by shifting from a single-pollutant approach to a multi-pollutant approach. To develop such multi-pollutant approaches, identifying which air pollutants are present most frequently is essential. This study aims to determine the frequently found carcinogenic air toxics or hazardous air pollutants (HAPs) combinations across the United States as well as to analyze the health impacts of developing cancer due to exposure to these HAPs. To identify the most commonly found carcinogenic air toxics combinations, we first identified HAPs with cancer risk greater than one in a million in more than 5% of the census tracts across the United States, based on the National-Scale Air Toxics Assessment (NATA) by the U.S. EPA for year 2005. We then calculated the frequencies of their two-component (binary), and three-component (ternary) combinations. To quantify the cancer-related health impacts, we focused on the 10 most frequently found HAPs with national average cancer risk greater than one in a million. Their cancer-related health impacts were calculated by converting lifetime cancer risk reported in NATA 2005 to years of healthy life lost or Disability-Adjusted Life Years (DALYs). We found that the most frequently found air toxics with cancer risk greater than one in a million are formaldehyde, carbon tetrachloride, acetaldehyde, and benzene. The most frequently occurring binary pairs and ternary mixtures are the various combinations of these four air toxics. Analysis of urban and rural HAPs did not reveal significant differences in the top combinations of these chemicals. The cumulative annual cancer-related health impacts of inhaling the top 10 carcinogenic air toxics included was about 1,600 DALYs in the United States or 0.6 DALYs per 100,000 people. Formaldehyde and benzene together contribute nearly 60 percent of the total cancer-related health impacts. Our study shows that although there are many

  17. Mutagenic activation reduces carcinogenic activity of ortho-aminoazotoluene for mouse liver.

    Science.gov (United States)

    Ovchinnikova, L P; Bogdanova, L A; Kaledin, V I

    2013-03-01

    Pentachlorophenol (aromatic amine and azo stain metabolic stimulation inhibitor) reduced the hepatocarcinogenic activity of 4-aminoazobenzene and reduced that of ortho-aminoazotoluene in suckling mice. Both 4-aminoazobenzene and ortho-aminoazotoluene exhibited mutagenic activity in Ames' test in vitro on S. typhimurium TA 98 strain with activation with liver enzymes; this mutagenic activity was similarly suppressed by adding pentachlorophenol into activation medium. Induction of xenobiotic metabolism enzymes, stimulating the mutagenic activity of ortho-aminoazotoluene, suppressed its carcinogenic effect on mouse liver. Hence, ortho-aminotoluene (the initial compound), but not its mutagenic metabolites, was the direct active hepatocarcinogen for mice.

  18. Preferential binding of growth inhibitory prostaglandins by the target protein of a carcinogen.

    OpenAIRE

    S H Khan; Sorof, S

    1990-01-01

    Liver fatty acid binding protein (L-FABP) is the principal target protein of the hepatic carcinogen N-(2-fluorenyl)acetamide (2-acetylaminofluorene) in rat liver. In addition, the cyclopentenone prostaglandins (PG), PGA, PGJ2, and delta 12-PGJ2, inhibit the growth of many cell types in vitro. This report describes the preferential binding of the growth inhibitory prostaglandins by L-FABP and the reversible inhibition of thymidine incorporation into DNA by PGA2 and delta 12-PGJ2 in primary cul...

  19. Plasma proteins as early biomarkers of exposure to carcinogenic aromatic amines.

    Science.gov (United States)

    Miller, M J; Parmelee, D C; Benjamin, T; Sechi, S; Dooley, K L; Kadlubar, F F

    1994-12-01

    Two-dimensional gel electrophoresis (2DG) has been used to study the changes induced in dog plasma polypeptides by the known urinary bladder carcinogens, 4-aminobiphenyl (4-ABP) and 2-naphthylamine (2-NA). Treatment with 3-aminobiphenyl (3-ABP) and 1-naphthylamine (1-NA), both considered to be non-carcinogenic, were used as controls. The purpose of this study was: (1) to determine whether or not changes that occurred in the plasma protein patterns were specific to 4-ABP and/or other related carcinogenic arylamines; (2) to measure the time course in the changes of the major polypeptides during dosing and their resynthesis during a recovery period; and (3) to determine, by microsequencing, the biochemical identity of the affected proteins. The results indicate that only the most potent carcinogen, 4-ABP, had the effect of suppressing the expression of some proteins, while the other aromatic amines caused no discernible change in the 2DG patterns during a 12-week dosing period. The 4-ABP caused dramatic suppression of two sets of proteins. One set of three spots had an apparent molecular weight of 32.5 kDa, and a pI of 5.8-6.0. The major component in this group was identified as the beta-chain of haptoglobin. Expression of this protein decreased markedly during the first 2 weeks of treatment and recovered slowly after dosing stopped. Since haptoglobin functions to bind with free hemoglobin and facilitates its elimination from the blood stream, these results can be rationalized as a consequence of 4-ABP binding to hemoglobin in the erythrocyte, resulting in cell death and hemolysis. The 4-ABP modified hemoglobin then binds to haptoglobin and this tertiary complex is purged from the blood stream, resulting in the disappearance of free haptoglobin. A second set of spots (mol. wt., 65 kDa; pI, 6.5-6.6) disappeared much faster than the haptoglobin, and recovered more quickly. The major protein is about one-fifth the intensity of haptoglobin and appeared to be N

  20. A theoretical concept of low level/low LET radiation carcinogenic risk (LLCR) projection

    Energy Technology Data Exchange (ETDEWEB)

    Filyushkin, I.V. [Laboratory of Theoretical Radiobiology, Moscow (Russian Federation)

    1992-06-01

    Carcinogenic risk to humans resulting from low level/low LET radiation exposure (LLLCR) has not been observed directly because epidemiological observations have not yet provided statistically significant data on risk values. However, these values are of great interest for radiation health science and radiation protection practice under both normal conditions and emergency situations. This report presents a theoretical contribution to the validation of dose and dose rate efficiency factors (DDREF) transforming cocinogenic risk coefficients from those revealed in A-bomb survivors to factors appropriate for the projection of the risk resulting from very low levels of low LET radiation.

  1. Formation and Human Risk of Carcinogenic Heterocyclic Amines Formed from Natural Precursors in Meat

    Energy Technology Data Exchange (ETDEWEB)

    Knize, M G; Felton, J S

    2004-11-22

    A group of heterocyclic amines that are mutagens and rodent carcinogens form when meat is cooked to medium and well-done states. The precursors of these compounds are natural meat components: creatinine, amino acids and sugars. Defined model systems of dry-heated precursors mimic the amounts and proportions of heterocyclic amines found in meat. Results from model systems and cooking experiments suggest ways to reduce their formation and, thus, to reduce human intake. Human cancer epidemiology studies related to consumption of well-done meat products are listed and compared.

  2. Potential health effects of exposure to carcinogenic compounds in incense smoke in temple workers.

    Science.gov (United States)

    Navasumrit, Panida; Arayasiri, Manasawee; Hiang, Ohmar May Tin; Leechawengwongs, Manoon; Promvijit, Jeerawan; Choonvisase, Suppachai; Chantchaemsai, Samroeng; Nakngam, Netnapa; Mahidol, Chulabhorn; Ruchirawat, Mathuros

    2008-05-01

    Incense smoke is a potential hazard to human health due to various airborne carcinogens emitted from incense burning. This study aimed to evaluate the potential health effects of exposure to benzene, 1,3-butadiene, and polycyclic aromatic hydrocarbons (PAHs) emitted from incense smoke in temple workers. Exposure and health risks were assessed through the measurement of ambient exposure as well as through the use of biomarkers of exposure and early biological effects. Ambient air measurement showed that incense burning generates significantly higher levels of airborne benzene (Pincense burning may increase health risk for the development of cancer in temple workers.

  3. Use of inverted intestinal sacs to assess the effect of gastrointestinal insult on carcinogen absorption.

    Science.gov (United States)

    Capel, I D; Cosier, R S; Pinnock, M H; Williams, D C

    1981-01-01

    Rats were subjected to various forms of treatment in the manner likely to induce gastrointestinal insult. These and control animals were sacrificed and, using inverted sacs, the rate of absorption of either dimethylnitrosamine and benzo(a)pyrene determined. The gastrointestinal injury resulting from the differing treatments did not significantly affect the absorption of benzo(a)pyrene, whereas that of dimethylnitrosamine was significantly increased after each incubation time, most notably by alcohol pretreatment. The results demonstrate that intestinal damage increases the absorption of some carcinogens.

  4. Carcinogen inducibility in vivo and down-regulation of DMBT1 during breast carcinogenesis

    DEFF Research Database (Denmark)

    Mollenhauer, Jan; Helmke, Burkhard; Medina, Daniel;

    2004-01-01

    unambiguous inactivating DMBT1 mutations in breast cancer. Expression analyses in the human and mouse mammary glands pointed to the necessity of DMBT1 induction. While age-dependent and hormonal effects could be ruled out, 9 of 10 mice showed induction of Dmbt1 expression after administration...... of the carcinogen 7,12-dimethybenz(alpha)anthracene prior to the onset of tumorigenesis or other histopathological changes. DMBT1 displayed significant up-regulation in human tumor-flanking tissues compared to in normal breast tissues (P ... secretion to secretion to the extracellular matrix and a significant down-regulation compared to that in matched normal flanking tissues (P

  5. Trichinella spiralis: Mere Co-Existence or Carcinogenic Parasite For Oral Squamous Cell Carcinoma?

    Science.gov (United States)

    Shirazi, Nadia; Bist, Sampan Singh; Ahmad, Sohaib; Harsh, Meena

    2015-10-01

    Trichinella spiralis is a parasite which is usually seen in pork-eaters. Most of the trichinosis infections cause little or no symptoms. We report a rare case of a middle aged North Indian male who presented with a painless ulcer in right buccal mucosa which was biopsied and reported as squamous cell carcinoma. Wide local excision was done subsequently which showed encysted larvae of Trichinella spiralis in the deeper skeletal muscle bundles. This article supports the carcinogenic potential of trichinosis and suggests timely work-up and treatment of the parasite. PMID:26557527

  6. Sorption, degradation and mobility of ptaquiloside, a carcinogenic Bracken (Pteridium sp.) constituent, in the soil environment

    DEFF Research Database (Denmark)

    Rasmussen, Lars Holm; Lauren, Denis; Hansen, Hans Christian Bruun

    2005-01-01

    very low sorption affinity with distribution coefficients in the range 0.01–0.22 l kg1 at a solution concentration of 1 mg l1 except for the most acid soil; Freundlich affinity coefficients increased linearly with clay and organic matter contents. Negligible sorption was also observed in column studies......Ptaquiloside (PTA) is a carcinogenic norsesquiterpene glucoside produced by Bracken in amounts up to at least 13 500 mg m2. The toxin is transferred from Bracken to the underlying soil from where it may leach to surface and groundwaters impairing the quality of drinking water. The objectives...

  7. Reproductive and carcinogenic health risks to hospital personnel from chemical exposure--a literature review.

    Science.gov (United States)

    Babich, H

    1985-01-01

    Hospital personnel, both those involved directly (surgeons, anesthesiologists, operating room nurses) and indirectly (pharmacists, laboratory technicians) with promoting the well-being of patients, and those involved in maintaining the proper functioning of the hospital (housekeeping personnel, painters, machinists), may be exposed to chemicals that are potential reproductive and carcinogenic hazards. Waste anesthetic gases, sterilants, such as ethylene oxide and formaldehyde, antineoplastic drugs, methylmethacrylate, asbestos, and various organic reagents and solvents may induce genetic damage, cancer, congenital malformation, still-birth, and spontaneous abortion. PMID:10274220

  8. Bacterial Metabolism in Humans of the Carcinogen IQ to the Direct Acting Mutagen Hydroxy-IQ

    OpenAIRE

    Van Tassell, R L; Carman, R. J.; Kingston, D. G. I.; Wilkins, T D

    2011-01-01

    7-hydroxy-IQ is the major product of the bacterial metabolism of IQ, a potent dietary carcinogen. Yet, unlike IQ, hydroxy-IQ is directly active in the salmonella/microsomal mutagenicity assay. Two subjects consumed a meal of fried meats containing IQ but no detectable hydroxy-IQ. Hydroxy-IQ was isolated from the subjects’ faeces collected within 30 h following the fried meat meal; it was absent from the subjects’ faeces before and after the meal. This is the first evidence that hy...

  9. Differences in gene expression profiles in the liver between carcinogenic and non-carcinogenic isomers of compounds given to rats in a 28-day repeat-dose toxicity study.

    Science.gov (United States)

    Nakayama, Koji; Kawano, Yukiko; Kawakami, Yuuki; Moriwaki, Norichika; Sekijima, Masaru; Otsuka, Masanori; Yakabe, Yoshikuni; Miyaura, Hideki; Saito, Koichi; Sumida, Kayo; Shirai, Tomoyuki

    2006-12-15

    Some compounds have structural isomers of which one is apparently carcinogenic, and the other not. Because of the similarity of their chemical structures, comparisons of their effects can allow gene expression elicited in response to the basic skeletons of the isomers to be disregarded. We compared the gene expression profiles of male Fischer 344 rats administered by daily oral gavage up to 28 days using an in-house oligo microarray. 2-Acetylaminofluorene (2-AAF), 2,4-diaminotoluene (2,4-DAT), 2-nitropropane (2-NP), and 2-nitro-p-phenylenediamine (2-NpP) are hepatocarcinogenic. However, their isomers, 4-acetylaminofluorene (4-AAF), 2,6-diaminotoluene (2,6-DAT), 1-nitropropane (1-NP), and 4-nitro-o-phenylenediamine (4-NoP), are non-hepatocarcinogenic. Because of the limited carcinogenicity of 2-NpP, we attempted to perform two-parametric comparison analyses with (1) a set of 4 isomers: 2-AAF, 2,4-DAT, 2-NP, and 2-NpP as "carcinogenic", and 4-AAF, 2,6-DAT, 1-NP, and 4-NoP as "non-carcinogenic"; and (2) a set of 3 isomers: 2-AAF, 2,4-DAT, and 2-NP, as "carcinogenic", and 4-AAF, 2,6-DAT, and 1-NP as "non-carcinogenic". After ratio filtering and Welch's approximate t-test analysis, 54 and 28 genes were selected from comparisons between the sets of 3 and 4 isomers, respectively, for day 28 data. Using hierarchical clustering analysis with the 54 or 28 genes, 2-AAF, 2,4-DAT, and 2-NP clustered into a "carcinogenic" branch. 2-NpP was in the same cluster as 4-NoP and 4-AAF. This clustering corresponded to the previous finding that 2-NpP is not carcinogenic in male Fischer 344 rats, which indicates that comparing the differences in gene expression elicited by different isomers is an effective method of developing a prediction system for carcinogenicity. PMID:17070881

  10. Accurate modelling of UV written waveguide components

    DEFF Research Database (Denmark)

    Svalgaard, Mikael

    BPM simulation results of UV written waveguide components that are indistinguishable from measurements can be achieved on the basis of trajectory scan data and an equivalent step index profile that is very easy to measure.......BPM simulation results of UV written waveguide components that are indistinguishable from measurements can be achieved on the basis of trajectory scan data and an equivalent step index profile that is very easy to measure....

  11. Accurate modeling of UV written waveguide components

    DEFF Research Database (Denmark)

    Svalgaard, Mikael

    BPM simulation results of UV written waveguide components that are indistinguishable from measurements can be achieved on the basis of trajectory scan data and an equivalent step index profile that is very easy to measure.......BPM simulation results of UV written waveguide components that are indistinguishable from measurements can be achieved on the basis of trajectory scan data and an equivalent step index profile that is very easy to measure....

  12. From ozone depletion to biological UV damage

    Energy Technology Data Exchange (ETDEWEB)

    Tamm, E.; Thomalla, E.; Koepke, P. [Munich Univ. (Germany). Meteorological Inst.

    1995-12-31

    Based on the ozone data from the Meteorological Observatory Hohenpeissenberg (MOHP: 47.8 deg N, 11.01 deg E) and corresponding mean atmospheric conditions, high resolution UV spectra are calculated with a complex radiation transfer model STAR. Biologically weighted UV spectra are investigated as integrated irradiances (dose rates) for maximum zenith angles and as daily integrals for selected days of the year. Ozone variation and uncertainty of action spectra are investigated

  13. Agent-Based Optimization

    CERN Document Server

    Jędrzejowicz, Piotr; Kacprzyk, Janusz

    2013-01-01

    This volume presents a collection of original research works by leading specialists focusing on novel and promising approaches in which the multi-agent system paradigm is used to support, enhance or replace traditional approaches to solving difficult optimization problems. The editors have invited several well-known specialists to present their solutions, tools, and models falling under the common denominator of the agent-based optimization. The book consists of eight chapters covering examples of application of the multi-agent paradigm and respective customized tools to solve  difficult optimization problems arising in different areas such as machine learning, scheduling, transportation and, more generally, distributed and cooperative problem solving.

  14. Users, Bystanders and Agents

    DEFF Research Database (Denmark)

    Krummheuer, Antonia Lina

    2015-01-01

    Human-agent interaction (HAI), especially in the field of embodied conversational agents (ECA), is mainly construed as dyadic communication between a human user and a virtual agent. This is despite the fact that many application scenarios for future ECAs involve the presence of others. This paper...... the construction of the agent’s identity, and (3) how HAI, as a mediated interaction, is framed by an asymmetric participation framework. The paper concludes by suggesting various participation roles, which may inform development of ECAs....

  15. Impact of fouling on UV effectiveness

    Energy Technology Data Exchange (ETDEWEB)

    Dykstra, T.S. [Dalhouse Univ., Dept. of Civil Engineering, Halifax, Nova Scotia (Canada); Chauret, C. [Indiana Univ. Kokomo, Kokomo, Biological and Physical Sciences, Indiana (United States)

    2002-06-15

    In recent years ultraviolet light has gained in popularity as an attractive disinfection alternative due to its ability to inactivate bacteria and viruses. UV light has the potential to inactivate Cryptosporidium parvum and Giardia lamblia with a very low potential for the formation of harmful disinfection by-products. Previous studies have reported that particulate material present in the water can act to reduce the exposure of UV light to the receiving waters and that the interference of organic particles can serve to protect bacteria and viruses from intended disinfection. Disinfection capacity can also be reduced by organics in the source water that can accumulate on the surface of quartz sleeves. The purpose of this study was to determine the ability of a medium pressure UV light, at drinking water treatment levels, to inactivate MS 2 bacteriophage after a quartz tube has been fouled with organic rich source water for a 12- week period. To this end the inactivation of MS 2 was determined under clean and fouled conditions, in the presence and absence of humic rich water. The effect of lamp age on inactivation was also investigated. The results suggest that organic fouling of a quartz tube has a significant impact on the disinfection capacity of a medium pressure UV lamp. The presence of organics in the source water also plays a significant role in reducing the capacity of UV for bacterial and viral disinfection. Lamp age also seems to have some effect on the efficiency of UV disinfection. (author)

  16. Photodegradation and toxicity changes of antibiotics in UV and UV/H2O2 process

    International Nuclear Information System (INIS)

    The photodegradation of three antibiotics, oxytetracycline (OTC), doxycycline (DTC), and ciprofloxacin (CIP) in UV and UV/H2O2 process was investigated with a low-pressure UV lamp system. Experiments were performed in buffered ultrapure water (UW), local surface water (SW), and treated water from local municipal drinking water treatment plant (DW) and wastewater treatment plant (WW). The efficiency of UV/H2O2 process was affected by water quality. For all of the three selected antibiotics, the fastest degradation was observed in DW, and the slowest degradation occurred in WW. This phenomenon can be explained by ROH,UV, defined as the experimentally determined ·OH radical exposure per UV fluence. The ROH,UV values represent the background ·OH radical scavenging in water matrix, obtained by the degradation of para-chlorobenzoic acid (pCBA), a probe compound. In natural water, the indirect degradation of CIP did not significantly increase with the addition of H2O2 due to its effective degradation by UV direct photolysis. Moreover, the formation of several photoproducts and oxidation products of antibiotics in UV/H2O2 process was identified using GC-MS. Toxicity assessed by Vibrio fischer (V. fischer), was increased in UV photolysis, for the photoproducts still preserving the characteristic structure of the parent compounds. While in UV/H2O2 process, toxicity increased first, and then decreased; nontoxic products were formed by the oxidation of ·OH radical. In this process, detoxification was much easier than mineralization for the tested antibiotics, and the optimal time for the degradation of pollutants in UV/H2O2 process would be determined by parent compound degradation and toxicity changes.

  17. Effect of UV irradiation on the apoptosis and necrosis of Jurkat cells using UV LEDs

    Science.gov (United States)

    Inada, Shunko A.; Amano, Hiroshi; Akasaki, Isamu; Morita, Akimichi; Kobayashi, Keiko

    2009-02-01

    Phototherapy is a very effective method for treating most of the incurable skin diseases. A fluorescent light bulb is used as a conventional UV light source for this type of therapy. However, infrared radiation from the light source sometimes causes serious problems on patient's health. In addition, the normal part of the skin is irradiated when a large fluorescent light bulb is used. Moreover, a conventional UV irradiation system is heavy and has a short lifetime and a high electrical power consumption. Therefore, a new UV light source for solving the problems of phototherapy is required. To realize low-power-consumption, lightweight and long-lifetime systems, group III nitride-based UV-A1 light-emitting diodes (LEDs) were investigated. We examined the UV LED irradiation of Jurkat cell, which is a tumor cell and more sensitive to UV light than a healthy cell. The numbers of apoptotic and necrotic cells were confirmed to be the same using a UV LED and a conventional lamp system. The UV LED showed the possibility of realizing a new UV light source for phototherapy.

  18. Pre main sequence stars as UV sources for the World Space Observatory-UV mission

    Science.gov (United States)

    Gomez de Castro, Ana I.; Lamzin, Sergei A.

    2011-09-01

    Pre-main sequence stars are bright UV (UV) sources compared with their main sequence analogues. The source of this excess is the high energy processes associated with the physics of accretion/outflow during early stellar evolution. In this review, the main sources of UV excess are described as well as the most significant "unknowns" in the field. Special emphasis is made on the results from the last observations carried out with the Hubble Space Telescope and on the relevance of future dedicated monitoring programs with the World Space Observatory-UV.

  19. Agent Standards Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The innovation of the work herein proposed is the development of standards for software autonomous agents. These standards are essential to achieve software...

  20. Biodegradability of iopromide products after UV/H₂O₂ advanced oxidation.

    Science.gov (United States)

    Keen, Olya S; Love, Nancy G; Aga, Diana S; Linden, Karl G

    2016-02-01

    Iopromide is an X-ray and MRI contrast agent that is virtually non-biodegradable and persistent through typical wastewater treatment processes. This study determined whether molecular transformation of iopromide in a UV/H2O2 advanced oxidation process (AOP) can result in biodegradable products. The experiments used iopromide labeled with carbon-14 on the aromatic ring to trace degradation of iopromide through UV/H2O2 advanced oxidation and subsequent biodegradation. The biotransformation assay tracked the formation of radiolabeled (14)CO2 which indicated full mineralization of the molecule. The results indicated that AOP formed biodegradable iopromide products. There was no (14)C released from the pre-AOP samples, but up to 20% of all radiolabeled carbon transformed into (14)CO2 over the course of 42 days of biodegradation after iopromide was exposed to advanced oxidation (compared to 10% transformation in inactivated post-AOP controls). In addition, the quantum yield of photolysis of iopromide was determined using low pressure (LP) and medium pressure (MP) mercury lamps as 0.069 ± 0.005 and 0.080 ± 0.007 respectively. The difference in the quantum yields for the two UV sources was not statistically significant at the 95% confidence interval (p = 0.08), which indicates the equivalency of using LP or MP UV sources for iopromide treatment. The reaction rate between iopromide and hydroxyl radicals was measured to be (2.5 ± 0.2) × 10(9) M(-1) s(-1). These results indicate that direct photolysis is a dominant degradation pathway in UV/H2O2 AOP treatment of iopromide. Other iodinated contrast media may also become biodegradable after exposure to UV or UV/H2O2.

  1. Programming Service Oriented Agents

    OpenAIRE

    Hirsch, Benjamin; Konnerth, Thomas; Burkhardt, Michael; Albayrak, Sahin

    2010-01-01

    This paper introduces a programming language for service-oriented agents. JADL++ combines the ease of use of scripting-languages with a state-of-the-art service oriented approach which allows the seamless integration of web-services. Furthermore, the language includes OWL-based ontologies for semantic descriptions of data and services, thus allowing agents to make intelligent decisions about service calls.

  2. Degradation of Pentachlorophenol in Aqueous Solution by the UV/ZrO 2 /H 2 O 2 Photocatalytic Process

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Samarghandi

    2015-12-01

    Full Text Available Pentachlorophenol (PCP, which is one of the resistant phenolic compounds, has been classified in the category of EPA’s priority pollutants due to its high toxicity and carcinogenic potential. Therefore, its removal from water and wastewater is very important. Various methods have been studied for removing the compound, among which advanced oxidation processes (AOPs have attracted much attention because of ease of application and high efficiency. Thus the aim of this study was to investigate the efficiency of the UV/ZrO2/H2O2 process, as an AOP, for PCP removal from aquatic environments. The effects of several parameters such as ultraviolet (UV exposure time, initial PCP concentration, pH, concentration of zirconium dioxide (ZrO2 nanoparticles, and H2O2 concentration were studied. Kinetics of the reaction was also detected. The concentration of the stated materials in the samples was determined using a spectrophotometer at 500 nm. The results showed that the highest efficiency (approximately 100% was reached at optimized conditions of pH 6, contact time of 30 minutes, initial PCP concentration of 20 mg/L, the nanoparticles concentration of 0.1 g/L and H2O2 concentration of 14.7 mM/L. Also, the process followed the first order kinetics reaction. The obtained results illustrated that the UV/ZrO2/H2O2 process has a high ability in removing PCP.

  3. ACTINIDE-SPECIFIC SEQUESTERING AGENTS AND DECONTAMINATION APPLICATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Smith, William L.; Raymond, Kenneth N.

    1980-07-01

    We have briefly reviewed the biological hazards associated with the actinide elements. The most abundant transuranium element produced by both industrial nuclear power plants and nuclear weapons programs is plutonium. It is also potentially the most toxic - particularly due to its long-term hazard as a carcinogen if it is introduced into the body. This toxicity is due in large part to the chemical and biochemical similarities of Pu(IV) and Fe(III). Thus in mammals plutonium is transported and stored by the transport and storage systems for iron. This results in the concentration and long-term retention of an alpha-emitting radionuclide ({sup 239}Pu) at sites such as the bone marrow where cell division occurs at a high rate. The earliest attempts at removal of actinide contamination by chelation therapy were essentially heuristic in that sequestering agents known to be effective at binding other elements were tried with plutonium. The research described here is intended to be a rational approach that begins with the observation that since Fe(III) and Pu(IV) are so similar, and since microbes produce agents called siderophores that are extremely effective and selective sequestering agents for Fe(III), the construction of similar chelating agents for the actinides should be possible using the same chelating groups found in the siderophores. The incorporation of four such groups (primarily catechol and hydroxamic acid) results in multidentate chelating agents that can completely encapsulate the central actinide(IV) ion and achieve the eight-coordinate environment most favored by such ions. The continuing development and improvement of such sequestering agents has produced compounds which remove significant amounts of plutonium deposited in bone and which remove a greater fraction of the total body burden than any other chelation therapy developed to date.

  4. Genotoxicity, carcinogenicity, and mode of action of the fried food mutagen 2-amino-3-methylimidazo[4,5-f]quinoline (IQ).

    OpenAIRE

    Weisburger, J H; Barnes, W S; Lovelette, C A; Tong, C; Tanaka, T; Williams, G.M.

    1986-01-01

    Because mutagens typified by 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) observed in cooked foods are widely consumed, detailed studies of their biochemical and biological properties including carcinogenicity are most important. IQ induces unscheduled DNA synthesis in liver cells, which when taken together with its powerful mutagenicity in the Salmonella typhimurium test system, predicts carcinogenicity. In female Sprague-Dawley rats, IQ did exhibit potent carcinogenicity for the mammary gla...

  5. Resonance Enhanced Multi-Photon Ionization (rempi) and Double Resonance Uv-Uv and Ir-Uv Spectroscopic Investigation Isocytosine

    Science.gov (United States)

    Lee, Seung Jun; Min, Ahreum; Ahn, Ahreum; Moon, Cheol Joo; Choi, Myong Yong; Ishiuchi, Shun-Ichi; Miyazaki, Mitsuhiko; Fujii, Masaaki

    2013-06-01

    Isocytosine(iC), 2-aminouracil, is a non-natural nucleobase and its functional group's positions resemble those of guanine; therefore, its spectroscopic investigation is worthy of attention especially for the natural/unnatural base pairs with guanine and isoguanine. In this study, resonance enhanced multi-photon ionization (REMPI) and UV/IR-UV double resonance spectra of iC in the gas phase are presented. The collaboration work between Tokyo Institute of Technology, Japan and Gyeongsang National University, Korea using laser ablation and thermal evaporation, respectively, for producing jet-cooled iC is presented and discussed. The REMPI spectrum of iC monomers is recorded in the spectral range of 35000 to 36400cm-1, showing very congested π-π* vibronic bands. UV-UV hole burning spectroscopy is further conducted to investigate the conformational landscapes of iC monomers. Moreover, the presence of free OH band from IR-UV double resonance spectroscopy in combination with quantum chemical calculations convinces that the iC monomer in free-jet expansion experiment is an enol tautomer. However, a possible presence of a keto tautomer of iC may be provided by employing a pico-second experiment on iC.

  6. The carcinogenic risks of low-LET and high-LET ionizing radiations

    International Nuclear Information System (INIS)

    This report presents a discussion on risk from ionizing radiations to human populations. Important new information on human beings has come mainly from further follow-up of existing epidemiological studies, notably the Japanese atomic bomb survivors and the ankylosing spondylitis patients; from new epidemiological surveys, such as the patients treated for cancer of the uterine cervix; and from combined surveys, including workers exposed in underground mines. Since the numerous and complex differences among the different study populations introduce factors that influence the risk estimates derived in ways that are not completely understood, it is not clear how to combine the different risk estimates obtained. These factors involve complex biological and physical variables distributed over time. Because such carcinogenic effects occur too infrequently to be demonstrated at low doses, the risks of low-dose radiation can be estimated only by interpolation from observations at high doses on the basis of theoretical concepts, mathematical models and available empirical evidence, primarily the epidemiological surveys of large populations exposed to ionizing radiation. In spite of a considerable amount of research, only recently has there has been efforts to apply the extensive laboratory data in animals to define the dose-incidence relationship in the low dose region. There simply are insufficient data in the epidemiological studies of large human populations to estimate risk coefficients directly from exposure to low doses. The risk estimates for the carcinogenic effects of radiation have been, in the past, somewhat low and reassessment of the numerical values is now necessary

  7. Solubility of chrysotile asbestos and basalt fibers in relation to their fibrogenic and carcinogenic action.

    Science.gov (United States)

    Kogan, F M; Nikitina, O V

    1994-10-01

    Fiber length and persistence are thought to be determinants for the development of toxic, fibrogenic, and carcinogenic effects of fibrous dusts. When the solubilities of chrysotile asbestos (CA) and basalt fibers (BF) were compared by measuring the loss of silica and magnesium in Leineweber's solution, CA was shown to be the more soluble. In a 6-month inhalation experiment, chrysotile at a mean concentration of 25 mg/m3 had a higher clearance rate than other comparable dusts. In acute toxicity studies, chrysotile and basalt fibers were administered intraperitoneally. At a dose of 1.7 g/kg body weight of CA, one third of the animals died. A dose of 2.7 g/kg body weight killed all the animals. With BF, even at a dose of 10 g/kg body weight all the animals survived. When the two fibers were administered over a 6-month period, either intratracheally or by inhalation, fibrotic lesions were more common in the group that received CA. Intraperitoneal administration of CA led to three times as many deaths from peritoneal mesothelioma as administration of BF. It appears, therefore, that in spite of its higher solubility and lower persistence, CA was the more toxic, fibrogenic and carcinogenic fiber, which gives rise to the hypothesis that the surface chemistry of the fibers is the determinant for biological activity.

  8. Biodegradation of carcinogenic textile azo dyes using bacterial isolates of mangrove sediment

    Institute of Scientific and Technical Information of China (English)

    Guru Prasad Srinivasan; Asnar Sikkanthar; Anandajothi Elamaran; Caroline R Delma; Kumaran Subramaniyan

    2014-01-01

    Objective:To evaluate the biodegrading property against carcinogenic azo dyes using bacterial isolates of mangrove sediment. Methods: The bacterial isolates were subjected to submerged fermentation and their growth kinetics were studied. The potential strain was characterized using 16S rDNA sequencing. Results:In the present study, dye degrading bacterial colonies were isolated from the mangrove sediment samples of Parangipettai estuarine area, Tamil Nadu. Of the 30 morphologically different strains isolated, 5 showed antagonistic property. The growth kinetics of the two strains, P1 and G1, which showed potent activity were calculated. One particular isolate (P1) showing promising dye degrading potential in the submerged fermentation was further characterized. The strain was identified as Paenibacillus sp. by 16S rDNA sequencing. Conclusions:This study reveals the less explored microflora of mangrove sediments. The novel strain may further be analyzed and used in the treatment of effluent from dye industry so as to reduce the impact of carcinogenic contaminants.

  9. Evaluation of genome damage in subjects occupationally exposed to possible carcinogens.

    Science.gov (United States)

    Zeljezic, Davor; Mladinic, Marin; Kopjar, Nevenka; Radulovic, Azra Hursidic

    2016-09-01

    In occupational exposures, populations are simultaneously exposed to a mixture of chemicals. We aimed to evaluate DNA damage due to possible carcinogen exposure (phenylhydrazine, ethylene oxide, dichloromethane, and 1,2-dichloroethane) in lymphocytes of pharmaceutical industry workers from the same production line. Population comprised 16 subjects (9 females and 7 males) who were exposed to multiple chemicals for 8 months. Genome damage was assessed using alkaline comet assay, micronucleus assay, and comet assay coupled with fluorescent in situ hybridization (comet-FISH). After 8 months of exposure, the issue of irregular use of all available personal protective equipment (PPE) came into light. To decrease the risk of exposure, strict use of PPE was enforced. After 8 months of strict PPE use, micronuclei frequency and comet assay parameters in lymphocytes of pharmaceutical workers significantly decreased compared with prior period of irregular PPE use. Comet-FISH results indicated a significant shift in distribution of signals for the TP 53 gene toward a more frequent occurrence in the comet tail. Prolonged exposure to possible carcinogens may hinder DNA repair mechanisms and affect structural integrity of TP 53 Two indicators of loss of TP 53 gene integrity have risen, namely, TP 53 fragmentation rate in lymphocytes with persistently elevated primary damage and incidence of TP 53 deletions in undamaged lymphocytes. PMID:25653038

  10. Antiproliferative effects of fluoxetine on colon cancer cells and in a colonic carcinogen mouse model.

    Directory of Open Access Journals (Sweden)

    Vinicius Kannen

    Full Text Available The antidepressant fluoxetine has been under discussion because of its potential influence on cancer risk. It was found to inhibit the development of carcinogen-induced preneoplastic lesions in colon tissue, but the mechanisms of action are not well understood. Therefore, we investigated anti-proliferative effects, and used HT29 colon tumor cells in vitro, as well as C57BL/6 mice exposed to intra-rectal treatment with the carcinogen N-methyl-N'-nitro-N-nitrosoguanidine (MNNG as models. Fluoxetine increased the percentage of HT29 cells in the G(0/G(1 phase of cell-cycle, and the expression of p27 protein. This was not related to an induction of apoptosis, reactive oxygen species or DNA damage. In vivo, fluoxetine reduced the development of MNNG-induced dysplasia and vascularization-related dysplasia in colon tissue, which was analyzed by histopathological techniques. An anti-proliferative potential of fluoxetine was observed in epithelial and stromal areas. It was accompanied by a reduction of VEGF expression and of the number of cells with angiogenic potential, such as CD133, CD34, and CD31-positive cell clusters. Taken together, our findings suggest that fluoxetine treatment targets steps of early colon carcinogenesis. This confirms its protective potential, explaining at least partially the lower colon cancer risk under antidepressant therapy.

  11. Impact of Environmental Exposures on the Mutagenicity/Carcinogenicity of Heterocyclic Amines

    Energy Technology Data Exchange (ETDEWEB)

    Felton, J S; Knize, M G; Bennett, L M; Malfatti, M A; Colvin, M E; Kulp, K S

    2003-12-19

    Carcinogenic heterocyclic amines are produced from overcooked foods and are highly mutagenic in most short-term test systems. One of the most abundant of these amines, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), induces breast, colon and prostate tumors in rats. Human dietary epidemiology studies suggest a strong correlation between either meat consumption or well-done muscle meat consumption and cancers of the colon, breast, stomach, lung and esophagus. For over 20 years our laboratory has helped define the human exposure to these dietary carcinogens. In this report we describe how various environmental exposures may modulate the risk from exposure to heterocyclic amines, especially PhIP. To assess the impact of foods on PhIP metabolism in humans, we developed an LC/MS/MS method to analyze the four major PhIP urinary metabolites following the consumption of a single portion of grilled chicken. Adding broccoli to the volunteers' diet altered the kinetics of PhIP metabolism. At the cellular level we have found that PhIP itself stimulates a significant estrogenic response in MCF-7 cells, but even more interestingly, co-incubation of the cells with herbal teas appear to enhance the response. Numerous environmental chemicals found in food or the atmosphere can impact the exposure, metabolism, and cell proliferation response of heterocyclic amines.

  12. Protein adducts of the prostate carcinogen PhIP in children

    Energy Technology Data Exchange (ETDEWEB)

    Lawrence Livermore National Laboratory

    2004-02-20

    Prostate cancer is the second leading cause of cancer death in men in the United States. few epidemiology studies have indicated that exposure to PhIP, a rodent prostate carcinogen formed in meat during cooking, may be an important risk factor for prostate cancer in humans. Therefore, a highly sensitive biomarker assay is urgently needed to clarify the role of PhIP in prostate cancer. The goal of this project is to develop an assay that can be used to more accurately quantify human exposure to PhIP and potential prostate cancer risk. Our hypothesis is that an Accelerator Mass Spectrometry-based method can be developed to measure protein adducts of PhIP in the blood of humans. This will provide a measure of the internal dose, as well as the capacity for carcinogen bioactivation to a form that can initiate the cancer process. Towards this goal, we have characterized an adduct formed by PhIP in vitro with the amino acid cysteine. This adduct should provide a biomarker of dietary PhIP exposure and potential prostate cancer risk that could be used to identify individuals for prevention and for monitoring the effect chemoprevention strategies.

  13. The OSIRIS Weight of Evidence approach: ITS mutagenicity and ITS carcinogenicity.

    Science.gov (United States)

    Buist, Harrie; Aldenberg, Tom; Batke, Monika; Escher, Sylvia; Klein Entink, Rinke; Kühne, Ralph; Marquart, Hans; Pauné, Eduard; Rorije, Emiel; Schüürmann, Gerrit; Kroese, Dinant

    2013-11-01

    Risk assessment of chemicals usually implies data evaluation of in vivo tests in rodents to conclude on their hazards. The FP7 European project OSIRIS has developed integrated testing strategies (ITS) for relevant toxicological endpoints to avoid unnecessary animal testing and thus to reduce time and costs. This paper describes the implementation of ITS mutagenicity and carcinogenicity in the public OSIRIS webtool. The data requirements of REACH formed the basis for these ITS. The main goal was to implement procedures to reach a conclusion on the adequacy and validity of available data. For the mutagenicity ITS a quantitative Weight of Evidence approach based on Bayesian statistics was developed and implemented. The approach allows an overall quality assessment of all available data for the five types of mutagenicity data requirements: in vitro bacterial mutagenicity, in vitro and in vivo chromosome aberration, in vitro and in vivo mammalian mutagenicity. For the carcinogenicity ITS a tool was developed to evaluate the quality of studies not conforming (entirely) to guidelines. In a tiered approach three quality aspects are assessed: documentation (reliability), study design (adequacy) and scope of examination (validity). The quality assessment is based on expert and data driven quantitative Weight of Evidence. PMID:23357514

  14. Absence of carcinogenic and anticarcinogenic effects of annatto in the rat liver medium-term assay.

    Science.gov (United States)

    Agner, A R; Barbisan, L F; Scolastici, C; Salvadori, D M F

    2004-10-01

    Annatto (Bixa orellana L.) is a natural food colorant extensively used in many processed foods, especially dairy products. The lower cost of production and the low toxicity, make annatto a very attractive and convenient pigment in substitution to the many synthetic colorants. In the present study we investigate the carcinogenic and anticarcinogenic effects of dietary annatto in Wistar rat liver using the preneoplastic glutathione S-transferase (GST-P) foci and DNA damage biomarkers. Annatto, containing 5% bixin, was administered in the diet at concentrations of 20, 200, and 1000 ppm (0.07; 0.80 and 4.23 bixin/kg body wt/day, respectively), continuously during 2 weeks before, or 8 weeks after DEN treatment (200 mg/kg body wt, i.p.), to evaluate its effect on the liver-carcinogenesis medium-term bioassay. The comet assay was used to investigate the modifying potential of annatto on DEN (20 mg/kg body wt)-induced DNA damage. The results showed that annatto was neither genotoxic nor carcinogenic at the highest concentration tested (1000 ppm). No protective effects were also observed in both GST-P foci development and comet assays. In conclusion, in such experimental conditions, annatto shows no hepatocarcinogenic effect or modifying potential against DEN-induced DNA damage and preneoplastic foci in the rat liver. PMID:15354320

  15. Automobile tires--a potential source of highly carcinogenic dibenzopyrenes to the environment.

    Science.gov (United States)

    Sadiktsis, Ioannis; Bergvall, Christoffer; Johansson, Christer; Westerholm, Roger

    2012-03-20

    Eight tires were analyzed for 15 high molecular weight (HMW) polycyclic aromatic hydrocarbons (PAH), using pressurized fluid extraction. The variability of the PAH concentrations determined between different tires was large; a factor of 22.6 between the lowest and the highest. The relative abundance of the analytes was quite similar regardless of tire. Almost all (92.3%) of the total extractable PAH content was attributed to five PAHs: benzo[ghi]perylene, coronene, indeno[1,2,3-cd]pyrene, benzo[e]pyrene, and benzo[a]pyrene. The difference in the measured PAH content between summer and winter tires varied substantially across manufacturers, making estimates of total vehicle fleet emissions very uncertain. However, when comparing different types of tires from the same manufacturer they had significantly (p = 0.05) different PAH content. Previously, there have been no data available for carcinogenic dibenzopyrene isomers in automobile tires. In this study, the four dibenzopyrene isomers dibenzo[a,l]pyrene, dibenzo[a,e]pyrene, dibenzo[a,i]pyrene, and dibenzo[a,h]pyrene constituted automobile tires may be a potential previously unknown source of carcinogenic dibenzopyrenes to the environment.

  16. The carcinogenic risks of low-LET and high-LET ionizing radiations. Revision

    Energy Technology Data Exchange (ETDEWEB)

    Fabrikant, J.I. [Lawrence Berkeley Lab., CA (United States)]|[California Univ., San Francisco, CA (United States)

    1991-08-01

    This report presents a discussion on risk from ionizing radiations to human populations. Important new information on human beings has come mainly from further follow-up of existing epidemiological studies, notably the Japanese atomic bomb survivors and the ankylosing spondylitis patients; from new epidemiological surveys, such as the patients treated for cancer of the uterine cervix; and from combined surveys, including workers exposed in underground mines. Since the numerous and complex differences among the different study populations introduce factors that influence the risk estimates derived in ways that are not completely understood, it is not clear how to combine the different risk estimates obtained. These factors involve complex biological and physical variables distributed over time. Because such carcinogenic effects occur too infrequently to be demonstrated at low doses, the risks of low-dose radiation can be estimated only by interpolation from observations at high doses on the basis of theoretical concepts, mathematical models and available empirical evidence, primarily the epidemiological surveys of large populations exposed to ionizing radiation. In spite of a considerable amount of research, only recently has there has been efforts to apply the extensive laboratory data in animals to define the dose-incidence relationship in the low dose region. There simply are insufficient data in the epidemiological studies of large human populations to estimate risk coefficients directly from exposure to low doses. The risk estimates for the carcinogenic effects of radiation have been, in the past, somewhat low and reassessment of the numerical values is now necessary.

  17. The carcinogenic risks of low-LET and high-LET ionizing radiations

    Energy Technology Data Exchange (ETDEWEB)

    Fabrikant, J.I. (Lawrence Berkeley Lab., CA (United States) California Univ., San Francisco, CA (United States))

    1991-08-01

    This report presents a discussion on risk from ionizing radiations to human populations. Important new information on human beings has come mainly from further follow-up of existing epidemiological studies, notably the Japanese atomic bomb survivors and the ankylosing spondylitis patients; from new epidemiological surveys, such as the patients treated for cancer of the uterine cervix; and from combined surveys, including workers exposed in underground mines. Since the numerous and complex differences among the different study populations introduce factors that influence the risk estimates derived in ways that are not completely understood, it is not clear how to combine the different risk estimates obtained. These factors involve complex biological and physical variables distributed over time. Because such carcinogenic effects occur too infrequently to be demonstrated at low doses, the risks of low-dose radiation can be estimated only by interpolation from observations at high doses on the basis of theoretical concepts, mathematical models and available empirical evidence, primarily the epidemiological surveys of large populations exposed to ionizing radiation. In spite of a considerable amount of research, only recently has there has been efforts to apply the extensive laboratory data in animals to define the dose-incidence relationship in the low dose region. There simply are insufficient data in the epidemiological studies of large human populations to estimate risk coefficients directly from exposure to low doses. The risk estimates for the carcinogenic effects of radiation have been, in the past, somewhat low and reassessment of the numerical values is now necessary.

  18. Preferential binding of growth inhibitory prostaglandins by the target protein of a carcinogen

    Energy Technology Data Exchange (ETDEWEB)

    Khan, S.H.; Sorof, S. (Fox Chase Cancer Center, Philadelphia, PA (United States))

    1990-12-01

    Liver fatty acid binding protein (L-FABP) is the principal target protein of the hepatic carcinogen N-(2-fluorenyl)acetamide (2-acetylaminofluorene) in rat liver. In addition, the cyclopentenone prostaglandins (PG), PGA, PGJ{sub 2}, and {Delta}{sup 12}-PGJ{sub 2}, inhibit the growth of many cell types in vitro. This report describes the preferential binding of the growth inhibitory prostaglandins by L-FABP and the reversible inhibition of thymidine incorporation into DNA by PGA{sub 2} and {Delta}{sup 12}-PGJ{sub 2} in primary cultures of purified rat hepatocytes. As a model ligand, ({sup 3}H)PGA{sub 1} bound to L-FABP specifically, reversibly, rapidly, and with high affinity. Its dissociation constants were 134 nM (high affinity) and 3.6 {mu}M (low affinity). The high-affinity finding of ({sup 3}H)PGA{sup 1} correlated with their growth inhibitory activities reported previously and here. The in vitro actions of L-FABP are compatible with those of a specific and dissociable carrier of growth inhibitory prostaglandins in rat hepatocytes and suggest that the carcinogen may usurp the cellular machinery of the growth inhibitory prostaglandins.

  19. Human gastric cancer, Helicobacter pylori and bracken carcinogens: A connecting hypothesis.

    Science.gov (United States)

    Oliveros-Bastidas, Alberto; Calcagno-Pissarelli, María Pía; Naya, Marlene; Ávila-Núñez, Jorge Luis; Alonso-Amelot, Miguel E

    2016-03-01

    Long term infection of Helicobacter pylori (Hp) virulent strains is a key factor in the genesis of human gastric cancer, and so are certain dietary proinflammatory and genotoxic compounds. Carcinogenic bracken fern (Pteridium spp.) is one of these. Toxins from this plant are consumed as bracken culinary preparations, through milk and meat of bracken-exposed livestock, and drain waters from bracken swards. Bracken toxin ptaquiloside (PtQ), a suspected human carcinogen, elicits complex responses in animals leading to death. PtQ and Hp might cooperate in gastric pathologies. This paper presents an hypothesis on PtQ-Hp association leading to the enhancement of carcinogenesis in the human gastric environment that might explain the high gastric cancer incidence and death rates among Hp-infected people living in bracken zones at two levels: (1) The macroscopic scale comprising the flow of PtQ in the human diet. (2) the microscopic scale encompassing (A) gastric luminal medium; (B) gastric mucus structure and mucin degradation elicited by Hp; (C) bacterial pH gradient modification of the gastric mucosa that favors PtQ survival and its penetration into epithelial tissue; (D) combined PtQ/Hp effects on gastric immune and inflammatory responses; (E) PtQ-Hp complementary activity at selected cell signaling cascades and genome disturbance. PMID:26632203

  20. Evaluation of carcinogenic hazard of diesel engine exhaust needs to consider revolutionary changes in diesel technology.

    Science.gov (United States)

    McClellan, Roger O; Hesterberg, Thomas W; Wall, John C

    2012-07-01

    Diesel engines, a special type of internal combustion engine, use heat of compression, rather than electric spark, to ignite hydrocarbon fuels injected into the combustion chamber. Diesel engines have high thermal efficiency and thus, high fuel efficiency. They are widely used in commerce prompting continuous improvement in diesel engines and fuels. Concern for health effects from exposure to diesel exhaust arose in the mid-1900s and stimulated development of emissions regulations and research to improve the technology and characterize potential health hazards. This included epidemiological, controlled human exposure, laboratory animal and mechanistic studies to evaluate potential hazards of whole diesel exhaust. The International Agency for Research on Cancer (1989) classified whole diesel exhaust as - "probably carcinogenic to humans". This classification stimulated even more stringent regulations for particulate matter that required further technological developments. These included improved engine control, improved fuel injection system, enhanced exhaust cooling, use of ultra low sulfur fuel, wall-flow high-efficiency exhaust particulate filters, exhaust catalysts, and crankcase ventilation filtration. The composition of New Technology Diesel Exhaust (NTDE) is qualitatively different and the concentrations of particulate constituents are more than 90% lower than for Traditional Diesel Exhaust (TDE). We recommend that future reviews of carcinogenic hazards of diesel exhaust evaluate NTDE separately from TDE.

  1. Butachlor, a suspected carcinogen, alters growth and transformation characteristics of mouse liver cells.

    Science.gov (United States)

    Ou, Y H; Chung, P C; Chang, Y C; Ngo, F Q; Hsu, K Y; Chen, F D

    2000-12-01

    Butachlor is a widely used herbicide in Asia and South America. Previous investigations have indicated that it is a suspected carcinogen. To understand more about the biological effects of butachlor on cultured cells and the mechanism(s) of its carcinogenicity, we studied the alteration of the growth characteristics that was induced by butachlor in normal mouse liver cells (BNL CL2). This study demonstrates that butachlor decreases the population-doubling time of BNL CL2 cells, suggesting that it stimulates cell proliferation. To support this finding, a thymidine incorporation assay was conducted and a similar result that butachlor stimulates cell proliferation was elucidated. In addition, we show that butachlor increases the saturation density of the BNL CL2 cells. When combined with the tumor initiator N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), butachlor transforms cells efficiently, as demonstrated by loss of contact inhibition. These findings indicate that butachlor alters the growth characteristics of BNL CL2 cells and suggest that butachlor may induce malignant transformation through stimulation of cell proliferation, alteration of cell cycle regulation, and suppression of cell density-dependent inhibition of proliferation.

  2. Biodegradation of carcinogenic textile azo dyes using bacterial isolates of mangrove sediment

    Directory of Open Access Journals (Sweden)

    Guru Prasad Srinivasan

    2014-02-01

    Full Text Available Objective: To evaluate the biodegrading property against carcinogenic azo dyes using bacterial isolates of mangrove sediment. Methods: The bacterial isolates were subjected to submerged fermentation and their growth kinetics were studied. The potential strain was characterized using 16S rDNA sequencing. Results: In the present study, dye degrading bacterial colonies were isolated from the mangrove sediment samples of Parangipettai estuarine area, Tamil Nadu. Of the 30 morphologically different strains isolated, 5 showed antagonistic property. The growth kinetics of the two strains, P1 and G1, which showed potent activity were calculated. One particular isolate (P1 showing promising dye degrading potential in the submerged fermentation was further characterized. The strain was identified as Paenibacillus sp. by 16S rDNA sequencing. Conclusions: This study reveals the less explored microflora of mangrove sediments. The novel strain may further be analyzed and used in the treatment of effluent from dye industry so as to reduce the impact of carcinogenic contaminants.

  3. Preferential binding of growth inhibitory prostaglandins by the target protein of a carcinogen

    International Nuclear Information System (INIS)

    Liver fatty acid binding protein (L-FABP) is the principal target protein of the hepatic carcinogen N-(2-fluorenyl)acetamide (2-acetylaminofluorene) in rat liver. In addition, the cyclopentenone prostaglandins (PG), PGA, PGJ2, and Δ12-PGJ2, inhibit the growth of many cell types in vitro. This report describes the preferential binding of the growth inhibitory prostaglandins by L-FABP and the reversible inhibition of thymidine incorporation into DNA by PGA2 and Δ12-PGJ2 in primary cultures of purified rat hepatocytes. As a model ligand, [3H]PGA1 bound to L-FABP specifically, reversibly, rapidly, and with high affinity. Its dissociation constants were 134 nM (high affinity) and 3.6 μM (low affinity). The high-affinity finding of [3H]PGA1 correlated with their growth inhibitory activities reported previously and here. The in vitro actions of L-FABP are compatible with those of a specific and dissociable carrier of growth inhibitory prostaglandins in rat hepatocytes and suggest that the carcinogen may usurp the cellular machinery of the growth inhibitory prostaglandins

  4. Removal of probable human carcinogenic polycyclic aromatic hydrocarbons from contaminated water using molecularly imprinted polymer.

    Science.gov (United States)

    Krupadam, Reddithota J; Khan, Muntazir S; Wate, Satish R

    2010-02-01

    A molecularly imprinted polymer (MIP) adsorbent for carcinogenic polycyclic aromatic hydrocarbons (PAHs) was prepared using a non-covalent templating technique. MIP particles sized from 2 to 5 microm were synthesized in acetonitrile by using six PAHs mix as a template, methacrylic acid as the functional monomer, and ethylene glycol dimethacrylate as the cross-linker. When compared with the non-imprinted polymer (NIP), the MIP showed an excellent affinity towards PAHs in aqueous solution with binding capacity (B(max)) of 687 microg g(-1)MIP, imprinting effect of 6, and a dissociation constant of 24 microM. The MIP exhibited significant binding affinity towards PAHs even in the presence of environmental parameters such as dissolved organic matter (COD) and total dissolved inorganic solids (TDS), suggesting that this material may be appropriate for removal of carcinogenic PAHs. The feasibility of removing PAHs from water by the MIP demonstrated using groundwater spiked with PAHs. In addition, the MIP reusability without any deterioration in performance was demonstrated at least ten repeated cycles.

  5. Biodegradation of the metallic carcinogen hexavalent chromium Cr(VI by an indigenously isolated bacterial strain

    Directory of Open Access Journals (Sweden)

    Das Alok

    2010-01-01

    Full Text Available Background : Hexavalent chromium [Cr(VI], a potential mutagen and carcinogen, is regularly introduced into the environment through diverse anthropogenic activities, including electroplating, leather tanning, and pigment manufacturing. Human exposure to this toxic metal ion not only causes potential human health hazards but also affects other life forms. The World Health Organization, the International Agency for Research on Cancer, and the Environmental Protection Agency have determined that Cr(VI compounds are known human carcinogens. The Sukinda valley in Jajpur District, Orissa, is known for its deposit of chromite ore, producing nearly 98% of the chromite ore in India and one of the prime open cast chromite ore mines in the world (CES, Orissa Newsletter. Materials and Methods: Our investigation involved microbial remediation of Cr(VI without producing any byproduct. Bacterial cultures tolerating high concentrations of Cr were isolated from the soil sample collected from the chromite-contaminated sites of Sukinda, and their bioaccumulation properties were investigated. Strains capable of growing at 250 mg/L Cr(VI were considered as Cr resistant. Results: The experimental investigation showed the maximum specific Cr uptake at pH 7 and temperature 30oC. At about 50 mg/L initial Cr(VI concentrations, uptake of the selected potential strain exceeded 98% within 12 h of incubation. The bacterial isolate was identified by 16S rRNA sequencing as Brevebacterium casei. Conclusion: Results indicated promising approach for microbial remediation of effluents containing elevated levels of Cr(VI.

  6. Exposure and Metabolic Activation Biomarkers of Carcinogenic Tobacco-Specific Nitrosamines.

    Science.gov (United States)

    Hecht, Stephen S; Stepanov, Irina; Carmella, Steven G

    2016-01-19

    Lung cancer is the leading cause of cancer death in the world, and cigarette smoking is its main cause. Oral cavity cancer is another debilitating and often fatal cancer closely linked to tobacco product use. While great strides have been made in decreasing tobacco use in the United States and some other countries, there are still an estimated 1 billion men and 250 million women in the world who are cigarette smokers and there are hundreds of millions of smokeless tobacco users, all at risk for cancer. Worldwide, lung cancer kills about three people per minute. This Account focuses on metabolites and biomarkers of two powerful tobacco-specific nitrosamine carcinogens, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and N'-nitrosonornicotine (NNN), considered to be among the main causes of lung cancer and oral cavity cancer in people who use tobacco products. Three properties of NNK and NNN are critical for successful biomarker studies: they are present in all tobacco products, they are tobacco-specific and are not found in any other product, and they are strong carcinogens. NNK and NNN are converted in humans to urinary metabolites that can be quantified by mass spectrometry as biomarkers of exposure to these carcinogens. They are also metabolized to diazonium ions and related electrophiles that react with DNA to form addition products that can be detected and quantified by mass spectrometry. These urinary metabolites and DNA addition products can serve as biomarkers of exposure and metabolic activation, respectively. The biomarkers of exposure, in particular the urinary NNK metabolites 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) and its glucuronides, have been extensively applied to document tobacco-specific lung carcinogen uptake in smokers and nonsmokers exposed to secondhand tobacco smoke. Highly sensitive mass spectrometric methods have been developed for quantitative analysis of these NNK metabolites as well as metabolites of NNN in human urine

  7. Exposure and Metabolic Activation Biomarkers of Carcinogenic Tobacco-Specific Nitrosamines.

    Science.gov (United States)

    Hecht, Stephen S; Stepanov, Irina; Carmella, Steven G

    2016-01-19

    Lung cancer is the leading cause of cancer death in the world, and cigarette smoking is its main cause. Oral cavity cancer is another debilitating and often fatal cancer closely linked to tobacco product use. While great strides have been made in decreasing tobacco use in the United States and some other countries, there are still an estimated 1 billion men and 250 million women in the world who are cigarette smokers and there are hundreds of millions of smokeless tobacco users, all at risk for cancer. Worldwide, lung cancer kills about three people per minute. This Account focuses on metabolites and biomarkers of two powerful tobacco-specific nitrosamine carcinogens, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and N'-nitrosonornicotine (NNN), considered to be among the main causes of lung cancer and oral cavity cancer in people who use tobacco products. Three properties of NNK and NNN are critical for successful biomarker studies: they are present in all tobacco products, they are tobacco-specific and are not found in any other product, and they are strong carcinogens. NNK and NNN are converted in humans to urinary metabolites that can be quantified by mass spectrometry as biomarkers of exposure to these carcinogens. They are also metabolized to diazonium ions and related electrophiles that react with DNA to form addition products that can be detected and quantified by mass spectrometry. These urinary metabolites and DNA addition products can serve as biomarkers of exposure and metabolic activation, respectively. The biomarkers of exposure, in particular the urinary NNK metabolites 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) and its glucuronides, have been extensively applied to document tobacco-specific lung carcinogen uptake in smokers and nonsmokers exposed to secondhand tobacco smoke. Highly sensitive mass spectrometric methods have been developed for quantitative analysis of these NNK metabolites as well as metabolites of NNN in human urine

  8. Comparison of Herpes simplex virus plaque development after viral treatment with anti-DNA or antilipid agents

    Energy Technology Data Exchange (ETDEWEB)

    Coohill, T.P.; Babich, M.; Taylor, W.D.; Snipes, W.

    1980-06-01

    The plaque development of Herpes simplex virus type 1 (HSV) is slower for viruses treated with two anti-DNA agents: ultraviolet radiation (uv) or n-acetoxy-2-acetyl-aminofluorene. For HSV treated with three antimembrane agents - butylated hydroxytoluene, acridine plus near uv radiation, or ether - the plaque development time is the same as for untreated viruses. These differences hold even for viruses that survived treatment that lowered viability below the 1% level. Gamma ray inactivation of HSV produces no change in plaque development even though this agent is believed to preferentially affect viral DNA.

  9. 2,3,7,8-Tetrachlorodibenzo-p-dioxin has both pro-carcinogenic and anti-carcinogenic effects on neuroendocrine prostate carcinoma formation in TRAMP mice.

    Science.gov (United States)

    Moore, Robert W; Fritz, Wayne A; Schneider, Andrew J; Lin, Tien-Min; Branam, Amanda M; Safe, Stephen; Peterson, Richard E

    2016-08-15

    It is well established that the prototypical aryl hydrocarbon receptor (AHR) agonist 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) can both cause and protect against carcinogenesis in non-transgenic rodents. But because these animals almost never develop prostate cancer with old age or after carcinogen exposure, whether AHR activation can affect cancer of the prostate remained unknown. We used animals designed to develop this disease, Transgenic Adenocarcinoma of the Mouse Prostate (TRAMP) mice, to investigate the potential role of AHR signaling in prostate cancer development. We previously reported that AHR itself has prostate tumor suppressive functions in TRAMP mice; i.e., TRAMP mice in which Ahr was knocked out developed neuroendocrine prostate carcinomas (NEPC) with much greater frequency than did those with both Ahr alleles. In the present study we investigated effects of AHR activation by three different xenobiotics. In utero and lactational TCDD exposure significantly increased NEPC tumor incidence in TRAMP males, while chronic TCDD treatment in adulthood had the opposite effect, a significant reduction in NEPC incidence. Chronic treatment of adult TRAMP mice with the low-toxicity selective AHR modulators indole-3-carbinol or 3,3'-diindolylmethane did not significantly protect against these tumors. Thus, we demonstrate, for the first time, that ligand-dependent activation of the AHR can alter prostate cancer incidence. The nature of the responses depended on the timing of AHR activation and ligand structures. PMID:27151233

  10. In vitro determination of carcinogenicity of sixty-four compounds using a bovine papillomavirus DNA-carrying C3H/10T(1/2) cell line.

    Science.gov (United States)

    Kowalski, L A; Laitinen, A M; Mortazavi-Asl, B; Wee, R K; Erb, H E; Assi, K P; Madden, Z

    2000-01-01

    A new in vitro test for predicting rodent carcinogenicity is evaluated against a testing database of 64 chemicals including both genotoxic and nongenotoxic carcinogens and carcinogens that normally require addition of an S-9 microsomal fraction for detection in the bacterial mutagenicity assay. The assay uses focus formation in a stable, bovine papillomavirus type 1 (BPV-1) DNA carrying C3H/10T(1/2) mouse embryo fibroblast cell line (T1) that does not require transfection, infection with virus, isolation of primary cells from animals, or addition of a microsomal fraction. Of a total database of 64 compounds, 92% of the carcinogens, promoters, or noncarcinogens were correctly predicted. Based on previously reported results, the test of bacterial mutagenicity would have correctly predicted 58% of carcinogens, promoters or noncarcinogens and the Syrian hamster embryo test would have correctly predicted 87% of carcinogens, promoters, or noncarcinogens of this database. Of carcinogens that normally require addition of an S-9 fraction, T1 cells correctly predicted rodent carcinogenicity of polyaromatic hydrocarbons, aflatoxins, azo-compounds, nitrosamines, and hydrazine without the addition of an S-9 fraction. Of nongenotoxic carcinogens, T1 cells correctly predicted diethylstilbestroel, diethylhexylphthalate, acetamides, alkyl halides, ethyl carbamate, and phorbol ester tumour promoters.

  11. Tholins as Coloring Agents on Pluto

    Science.gov (United States)

    Cruikshank, D. P.; Materese, C. K.; Imanaka, H.; Dalle Ore, C.; Sandford, S. A.; Nuevo, M.

    2015-12-01

    The shape of the reflectance spectrum of Pluto recorded with telescopes, 0.3-1.0 μm, shows the planet's yellow-red color (1). Additionally, multi-filter images of Pluto with the MVIC camera on the New Horizons spacecraft report concentrations of the coloring agent(s) in some regions of the surface, and apparent near absence in other regions. Tholins are refractory organic solids of complex structure and high molecular weight, with a wide range of color ranging from yellow and orange to dark red, and through tan to black. They are readily synthesized in the laboratory by energetic processing of mixtures of the ices (N2, CH4, CO) known on Pluto's surface (2), or the same molecules in the gas phase (3). Energy in the form of UV light, electrons, protons, or coronal discharge are all effective to one degree or another in producing various types of tholins; details of the composition and yield vary with experimental conditions. Chemical analysis of ice tholins shows carboxylic acids, urea, and HCN and other nitriles. Aromatic/olefinic, amide, and other functional groups are identified in XANES analysis (4). The ice tholins produce by e- irradiation have a higher concentration of N than UV ice tholins, with N/C ~0.9 (versus ~0.5 for UV tholins) and O/C~0.2. EUV photolysis of Pluto atmosphere analog yields pale yellow solids relatively transparent in the visual, and with aliphatic CH bonds prominent in IR spectra. This material may be responsible for Pluto's hazes (5). Various tholins are the principal coloring agents on Pluto's surface, probably Charon's colored region, and on numerous other outer Solar System bodies (6). Refs: 1. Cruikshank, D. P. et al. 2014 DPS abstract #419.04; 2. Cruikshank et al. 2015 Icarus 246, 82; 3. Krasnopolsky & Cruikshank 1999 JGR 104 E9, 21,979; 4. Materese, C. K. et al. 2014 Ap.J. 788:111, June 20; 5. Imanaka, H. et al. 2014 DPS abstract #419.10; 6. Cruikshank, D. P. et al. 2005 Adv. Space Res. 36, 178.

  12. Fibrous Filter to Protect Building Environments from Polluting Agents: A Review

    Science.gov (United States)

    Chavhan, Md. Vaseem; Mukhopadhyay, Arunangshu

    2016-04-01

    This paper discusses the use of fibrous filter to protect the building environments from air born polluting agents and especially of concern chemical, biological and radiological agents. Air-filtration includes removal of particulate from air and toxic gases from air. In air filtration, particulate which are mostly biological and radioactive types of agents can be removed by using mechanical and electrostatic filters. Some biological agents, which cannot be removed by air filtration alone, special techniques like antimicrobial finish, UV germicides, coated filters etc. are required. Biocide agent can be added into the fibre itself by grafting reaction to impart antimicrobial activity. Chemical agents like toxic gases can be removed by integrating adsorbents and sorbents in filters or by fibre modifications. It is also possible to impart catalytic conversion properties into the fibre to remove volatile gasous. Radioactive agents can be removed by particulate filter if present in the form of aerosol or by gas cleaning by the use of specific fibre impregnate.

  13. Carcinogenicity of trace elements with reference to evaluations made by the International Agency for Research on Cancer.

    Science.gov (United States)

    Boffetta, P

    1993-01-01

    The monograph program of the International Agency for Research of on Cancer has evaluated many trace elements for their carcinogenicity to humans. Five groups of compounds were considered human carcinogens: arsenic and arsenic compounds, beryllium and beryllium compounds, cadmium and cadmium compounds, hexavalent chromium compounds, and nickel compounds. Antimony trioxide, cobalt and cobalt compounds, lead and inorganic lead compounds, methylmercury compounds, and metallic nickel were considered possibly carcinogenic to humans. Antimony trisulfide, trivalent chromium compounds, metallic chromium, ferric oxide, organolead compounds, metallic mercury, inorganic mercury compounds, selenium and selenium compounds, and titanium dioxide were not classifiable. Trace elements studied to a limited extent include copper, manganese, tin, vanadium, and zinc. Among the problems are the lack of relevant data, the definition of active species, the extrapolation of the results of experimental studies to humans, the methodological problems of epidemiologic studies, and the possible anticarcinogenic activity of some trace elements. PMID:8159977

  14. Science Data Management for WSO-UV

    Science.gov (United States)

    Gomez De Castro, Ana; Sachkov, Mikhail; Marcos-Arenal, Pablo; Belén Perea Abarca, G.; Malkov, Oleg

    2016-07-01

    WSO-UV is a 170 primary space telescope that will work in the ultraviolet range (115-315 nm) of the spectrum providing instrumentation for spectroscopy and imaging. WSO-UV is a cornerstone project of the astronomical program of the Russian Space Agency with launch date 2021. Spain and Mexico participate in the project. Scientific observation with WSO-UV will be open to the world wide scientific community after the 1st year of mission. WSO-UV will handle three scientific programs: core, national and open. The core program will be run during the first two years of the mission and will provide unique results that will affect all branches of astrophysics. WSO-UV will be equipped with a camera for very deep imaging in the Hydrogen Lyman-alpha (Lya) line and will be orbiting in a High Earth Orbit (geosynchronous). As a result, it will provide the deepest images ever obtained in this fundamental tracer (Lya is the strongest spectral line in the Universe). In this talk, we describe the strategy for the Lya survey and the foreseen output products and data distribution policy.

  15. Increase in UV mutagenesis by heat stress on UV-irradiated E. coli cells.

    Science.gov (United States)

    Saha, Swati; Basu, Tarakdas

    2012-06-01

    When leu- auxotrophs of Escherichia coli, after UV irradiation, were grown at temperatures between 30 and 47°C, the frequency of UV-induced mutation from leu- to leu+ revertant increased as the UV dose and the temperature increased. For cells exposed to a UV dose of 45 J/m2, the mutation frequency at 47°C was 1.9 times that at 30°C; for a dose of 90 J/m2, it was 3.25 times; and for 135 J/m2, it was 4.8 times. Similar enhancement of reversion frequency was observed when the irradiated cells were grown at 30°C in the presence of a heat shock inducer, ethanol (8% v/v). Heat shock-mediated enhancement of UV mutagenesis did not occur in an E. coli mutant sigma 32 (heat shock regulator protein), but sigma 32 overexpression in the mutant strain (transformed with a sigma 32-bearing plasmid) increased the UV-induced mutation frequency. These results suggest that heat stress alone has no mutagenic property, but when applied to UV-damaged cells, it enhances the UV-induced frequency of cell mutation.

  16. Ozone layer - climate change interactions. Influence on UV levels and UV related effects

    NARCIS (Netherlands)

    Kelfkens G; Bregman A; de Gruijl FR; van der Leun JC; Piquet A; van Oijen T; Gieskes WWC; van Loveren H; Velders GJM; Martens P; Slaper H; NOP; LPI; LLO

    2002-01-01

    Ozone in the atmosphere serves as a partially protective filter against the most harmful part of the solar UV-spectrum. Decreases in ozone lead to increases in ambient UV with a wide variety of adverse effects on human health, aquatic and terrestrial ecosystems and food chains. Human health effect

  17. Comparison of in vivo genotoxic and carcinogenic potency to augment mode of action analysis: Case study with hexavalent chromium.

    Science.gov (United States)

    Thompson, Chad M; Bichteler, Anne; Rager, Julia E; Suh, Mina; Proctor, Deborah M; Haws, Laurie C; Harris, Mark A

    2016-04-01

    Recent analyses-highlighted by the International Workshops on Genotoxicity Testing Working Group on Quantitative Approaches to Genetic Toxicology Risk Assessment-have identified a correlation between (log) estimates of a carcinogen's in vivo genotoxic potency and in vivo carcinogenic potency in typical laboratory animal models, even when the underlying data have not been matched for tissue, species, or strain. Such a correlation could have important implications for risk assessment, including informing the mode of action (MOA) of specific carcinogens. When in vivo genotoxic potency is weak relative to carcinogenic potency, MOAs other than genotoxicity (e.g., endocrine disruption or regenerative hyperplasia) may be operational. Herein, we review recent in vivo genotoxicity and carcinogenicity data for hexavalent chromium (Cr(VI)), following oral ingestion, in relevant tissues and species in the context of the aforementioned correlation. Potency estimates were generated using benchmark doses, or no-observable-adverse-effect-levels when data were not amenable to dose-response modeling. While the ratio between log values for carcinogenic and genotoxic potency was ≥1 for many compounds, the ratios for several Cr(VI) datasets (including in target tissue) were less than unity. In fact, the ratios for Cr(VI) clustered closely with ratios for chloroform and diethanolamine, two chemicals posited to have non-genotoxic MOAs. These findings suggest that genotoxicity may not play a major role in the cancers observed in rodents following exposure to high concentrations of Cr(VI) in drinking water-a finding consistent with recent MOA and adverse outcome pathway (AOP) analyses concerning Cr(VI). This semi-quantitative analysis, therefore, may be useful to augment traditional MOA and AOP analyses. More case examples will be needed to further explore the general applicability and validity of this approach for human health risk assessment. PMID:27085472

  18. Extraction agents for the removal of polycyclic aromatic hydrocarbons (PAHs) from soil in soil washing technologies.

    Science.gov (United States)

    Lau, Ee Von; Gan, Suyin; Ng, Hoon Kiat; Poh, Phaik Eong

    2014-01-01

    Polycyclic aromatic hydrocarbons (PAHs) in soil have been recognised as a serious health and environmental issue due to their carcinogenic, mutagenic and teratogenic properties. One of the commonly employed soil remediation techniques to clean up such contamination is soil washing or solvent extraction. The main factor which governs the efficiency of this process is the solubility of PAHs in the extraction agent. Past field-scale soil washing treatments for PAH-contaminated soil have mainly employed organic solvents or water which is either toxic and costly or inefficient in removing higher molecular weight PAHs. Thus, the present article aims to provide a review and discussion of the alternative extraction agents that have been studied, including surfactants, biosurfactants, microemulsions, natural surfactants, cyclodextrins, vegetable oil and solution with solid phase particles. These extraction agents have been found to remove PAHs from soil at percentages ranging from 47 to 100% for various PAHs. PMID:24100092

  19. Study of Ascorbic Acid as Iron(III Reducing Agent for Spectrophotometric Iron Speciation

    Directory of Open Access Journals (Sweden)

    Antesar Elmagirbi

    2012-10-01

    Full Text Available The study of ascorbic acid as a reducing agent for iron(III has been investigated in order to obtain an alternative carcinogenic reducing agent, hydroxylamine, used in spectrophotometric standard method based on the formation of a red-orange complex of Fe(II-o-phenanthroline. The study was optimised with regards to ascorbic acid concentration as well as pH solution. The results showed that ascorbic acid showed maximum capacity as reducing agent of iron(III under concentration of 4.46.10-4 M and pH solution of 1-4.Under these conditions, ascorbic acid reduced iron(III proportionally and performed similarly to that of hydroxylamine.  The method gave result to linear calibration over the range of 0.2-2 mg/L withhigh accuracy of 97 % and relative standard deviation of less than 2 %. This method was successfully applied to assay iron speciation in water samples.

  20. Biological Warfare Agents

    Directory of Open Access Journals (Sweden)

    Dev Vrat Kamboj

    2006-10-01

    Full Text Available There is a long historic record of use of biological warfare (BW agents by warring countriesagainst their enemies. However, the frequency of their use has increased since the beginningof the twentieth century. World war I witnessed the use of anthrax agent against human beingsand animals by Germans, followed by large-scale field trials by Japanese against war prisonersand Chinese population during world war II. Ironically, research and development in biologicalwarfare agents increased tremendously after the Geneva Protocol, signed in 1925, because ofits drawbacks which were overcome by Biological and Toxin Weapons Convention (BTWC in1972. Biological warfare programme took back seat after the 1972 convention but biologicalagents regained their importance after the bioterrorist attacks of anthrax powder in 2001. In thelight of these attacks, many of which turned out to be hoax, general awareness is required aboutbiological warfare agents that can be used against them. This review has been written highlightingimportant biological warfare agents, diseases caused by them, possible therapies and otherprotection measures.