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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)

    Tsugane, Shoichiro

    2013-01-01

    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. Enhanced replication of UV-damaged Simian virus 40 DNA in carcinogen-treated mammalian cells

    International Nuclear Information System (INIS)

    Maga, J.A.

    1983-01-01

    The replication of UV-damaged Simian virus 40 (SV40) in carcinogen-treated monkey cells has been studied to elucidate the mechanism of carcinogen-enhanced reactivation. Carcinogen enhanced reactivation is the observed increase in UV-irradiated virus survival in host cells treated with low doses of carcinogen compared to UV-irradiated virus survival in untreated hosts. Carcinogen treatment of monkey kidney cells with either N-acetoxy-2-acetylaminofluorene (AAAF) or UV radiation leads to an enhanced capacity to replicate UV-damaged virus during the first round of infection. To further define the mechanism leading to enhanced replication, a detailed biochemical analysis of replication intermediates in carcinogen-treated cells was performed. Several conclusions can be drawn. First enhanced replication can be observed in the first four rounds of replication after UV irradiation of viral templates. The second major finding is that the relaxed circular intermediate model proposed for the replication of UV-damaged templates in untreated cells appears valid for replication of UV-damaged templates in carcinogen-treated cells. Possible mechanisms and the supporting evidence are discussed and future experiments outlined

  3. Toxic and carcinogenic agents in dry and moist snuff.

    Science.gov (United States)

    Hoffmann, D; Adams, J D; Lisk, D; Fisenne, I; Brunnemann, K D

    1987-12-01

    The oral use of snuff is causatively associated with cancer of the oral cavity. Since most epidemiologic studies to date relate to the long-term use of dry snuff, which has dominated the U.S. smokeless tobacco market in the past, the concentrations of several toxic and carcinogenic agents in the three most popular dry snuff brands have been compared with those in the five most popular moist snuff brands sold in the United States. All eight samples were analyzed for nitrate, alkaloids, polyphenols, volatile carbonyl compounds, lead, cadmium, selenium, and the carcinogenic compounds benzo[a]pyrene (CAS: 50-32-8), polonium-210 (CAS: 13981-52-7), volatile N-nitrosamines (VNAs), N-nitrosodiethanolamine (CAS: 1116-54-7), and the tobacco-specific N-nitrosamines (TSNAs). Most of the snuff brands were rich in nitrate (greater than or equal to 1.5%), total polyphenols (greater than 2%), and in nicotine (greater than or equal to 1.5%), which is the habituating factor in tobacco use. Concentrations of the VNAs were significantly above the permissible limits set for some food products; the concentrations of the TSNAs in both snuff types exceeded the levels of nitrosamines in other consumer products by at least two to three orders of magnitude. The extremely high levels of the TSNAs in snuff have remained unchanged during the last decade and present the major carcinogenic risk factor for the oral use of snuff. Polonium-210 contributes further to the carcinogenic risk associated with snuff. The chemical-analytical data presented in this study do not indicate marked differences in the carcinogenic potential of moist snuff compared to dry snuff.

  4. DNA repair in mammalian cells exposed to combinations of carcinogenic agents

    International Nuclear Information System (INIS)

    Setlow, R.B.; Ahmed, F.E.

    1979-01-01

    Cells defective in one or more aspects of repair are killed and often mutagenized more readily than normal cells by DNA damaging agents, and humans whose cells are deficient in repair are at an increased carcinogenic risk compared to normal individuals. The excision repair of uv induced pyrimidine dimers is a well studied system, but the details of the steps in this repair system are far from being understood in human cells. We know that there are a number of chemicals that mimic uv in that normal human cells repair DNA damage from both these agents and from uv by a long patch excision repair system, and that xeroderma pigmentosum cells defective in repair of uv are also defective in the repair of damage from these chemicals. The chemicals we have investigated are AAAF, 4-NQO, DMBA-epoxide, and ICR-170. We describe experiments, using several techniques, in which DNA excision repair is measured after treatment of various human cell strains with combinations of uv and these agents. If two agents have a common rate limiting step then, at doses high enough to saturate the repair system, one would expect the observed repair after a treatment with a combination of agents to be equal to that from one agent alone. Such is not the case for normal human or excision-deficient XP cells. In the former repair is additive and in the latter repair is usually appreciably less than that observed with either agent alone. Models that attempt to explain these surprising results involve complexes of enzymes and cofactors

  5. Carcinogenic effect of sequential artificial sunlight and UV-A irradiation in hairless mice. Consequences for solarium 'therapy'

    International Nuclear Information System (INIS)

    Staberg, B.; Wulf, H.C.; Poulsen, T.; Klemp, P.; Brodthagen, H.

    1983-01-01

    The carcinogenic effect of artificial UV sunlight followed by UV-A irradiation in human solaria doses has been studied with the use of the hairless mouse as an animal model. Artificial sunlight exposure alone induced only a moderate skin tumor incidence (animals with at least one tumor) of 0.15 after one year, and UV-A irradiation alone induced no tumor formation. However, the combination of artificial sunlight exposure and subsequent UV-A irradiation significantly increased the tumor incidence to 0.72. We conclude that, in humans, tanning with UV-A for cosmetic purposes may not be an innocuous procedure

  6. DNA repair in human cells exposed to combinations of carcinogenic agents

    International Nuclear Information System (INIS)

    Setlow, R.B.; Ahmed, F.E.

    1980-01-01

    Normal human and XP 2 fibroblasts were treated with uv plus uv-mimetic chemicals. The uv dose used was sufficient to saturate the uv excision repair system. Excision repair after combined treatments was estimated by unscheduled DNA synthesis, BrdUrd photolysis, and the loss of sites sensitive to a uv specific endonuclease. Since the repair of damage from uv and its mimetics is coordinately controlled we expected that there would be similar rate-limiting steps in the repair of uv and chemical damage and that after a combined treatment the total amount of repair would be the same as from uv or the chemicals separately. The expectation was not fulfilled. In normal cells repair after a combined treatment was additive whereas in XP cells repair after a combined treatment was usually less than after either agent separately. The chemicals tested were AAAF, DMBA-epoxide, 4NQO, and ICR-170

  7. 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

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

    International Nuclear Information System (INIS)

    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

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

    International Nuclear Information System (INIS)

    Chaves, Jorge; Partanen, Timo; Wesseling, Catharina; Chaverri, Fabio; Monge, Patricia; Ruepert, Clemens; Guardado, Jorge; Aragon, Aurora; Kauppinen, Timo

    2004-01-01

    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) [es

  10. MGMT: key node in the battle against genotoxicity, carcinogenicity and apoptosis induced by alkylating agents.

    Science.gov (United States)

    Kaina, Bernd; Christmann, Markus; Naumann, Steffen; Roos, Wynand P

    2007-08-01

    O(6)-methylguanine-DNA methyltransferase (MGMT) plays a crucial role in the defense against alkylating agents that generate, among other lesions, O(6)-alkylguanine in DNA (collectively termed O(6)-alkylating agents [O(6)AA]). The defense is highly important, since O(6)AA are common environmental carcinogens, are formed endogenously during normal cellular metabolism and possibly inflammation, and are being used in cancer therapy. O(6)AA induced DNA damage is subject to repair, which is executed by MGMT, AlkB homologous proteins (ABH) and base excision repair (BER). Although this review focuses on MGMT, the mechanism of repair by ABH and BER will also be discussed. Experimental systems, in which MGMT has been modulated, revealed that O(6)-methylguanine (O(6)MeG) and O(6)-chloroethylguanine are major mutagenic, carcinogenic, recombinogenic, clastogenic and killing lesions. O(6)MeG-induced clastogenicity and cell death require MutS alpha-dependent mismatch repair (MMR), whereas O(6)-chloroethylguanine-induced killing occurs independently of MMR. Extensive DNA replication is required for O(6)MeG to provoke cytotoxicity. In MGMT depleted cells, O(6)MeG induces apoptosis almost exclusively, barely any necrosis, which is presumably due to the remarkable ability of secondarily formed DNA double-strand breaks (DSBs) to trigger apoptosis via ATM/ATR, Chk1, Chk2, p53 and p73. Depending on the cellular background, O(6)MeG activates both the death receptor and the mitochondrial apoptotic pathway. The inter-individual expression of MGMT in human lymphocytes is highly variable. Given the key role of MGMT in cellular defense, determination of MGMT activity could be useful for assessing a patient's drug sensitivity. MGMT is expressed at highly variable amounts in human tumors. In gliomas, a correlation was found between MGMT activity, MGMT promoter methylation and response to O(6)AA. Although the human MGMT gene is inducible by glucocorticoids and genotoxins such as radiation and

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

    International Nuclear Information System (INIS)

    Gentner, N.E.; Morrison, D.P.

    1988-01-01

    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

  12. 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.

  13. 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)

    1997-12-31

    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.

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

    International Nuclear Information System (INIS)

    Rajewsky, M.F.

    1983-01-01

    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, 10 9 to > 10 10 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 0 6 -N-butyldeoxyguanosine, and 0 4 -ethyldeoxythymidine. When used in a radioimmunassay, an antibody specific for 0 6 -ethyldeoxyguanosine, for example, will detect this product at an 0 6 -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

  15. Critical effective methods to detect genotoxic carcinogens and neoplasm-promoting agents.

    OpenAIRE

    Weisburger, J H; Williams, G M

    1991-01-01

    Neoplasia in fish can result from contamination of waters with carcinogens and promoters. Cancer in fish, therefore, is a possible indicator of cancer risk to man and serves as a guide to the need for preventive approaches involving improved means of waste disposal and environmental hygiene. Moreover, cancer in fish indicates that this important food source may be contaminated. Detection of genotoxic carcinogens to which fish are exposed can be achieved quickly and efficiently by carefully se...

  16. Theoretical Calculation of the Uv-Vis Spectral Band Locations of Pahs with Unknown Syntheses Procedures and Prospective Carcinogenic Activity

    Science.gov (United States)

    Ona-Ruales, Jorge Oswaldo; Ruiz-Morales, Yosadara

    2017-06-01

    Annellation Theory and ZINDO/S semiempirical calculations have been used for the calculation of the locations of maximum absorbance (LMA) of the Ultraviolet-Visible (UV-Vis) of 31 C_{34}H_{16} PAHs (molecular mass 424 Da) with unknown protocols of synthesis. The presence of benzo[a]pyrene bay-like regions and dibenzo[a,l]pyrene fjord-like regions in several of the structures that could be linked to an enhancement of the biological behavior and carcinogenic activity stresses the importance of C_{34}H_{16} PAHs in fields like molecular biology and cancer research. In addition, the occurrence of large PAHs in oil asphaltenes exemplifies the importance of these calculations for the characterization of complex systems. The C_{34}H_{16} PAH group is the largest molecular mass group of organic compounds analyzed so far following the Annellation Theory and ZINDO/S methodology. Future analysis using the same approach will provide evidence regarding the LMA of other high molecular mass PAHs.

  17. Carcinogenic agents present in the atmosphere and incidence of primary lung tumors in mice

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, J A

    1939-01-01

    Exposure of mice to suspended benzene extracts of exhaust pipe soot from engine burning heavy oil for once/hr, 6 hr/day, for a lifetime, produced a slight increase in lung tumors whereas chimney soot had no effect. Conversely, chimney soot extract painted on skin was judged carcinogenic, whereas exhaust soot did not produce cancer.

  18. Critical effective methods to detect genotoxic carcinogens and neoplasm-promoting agents.

    Science.gov (United States)

    Weisburger, J H; Williams, G M

    1991-01-01

    Neoplasia in fish can result from contamination of waters with carcinogens and promoters. Cancer in fish, therefore, is a possible indicator of cancer risk to man and serves as a guide to the need for preventive approaches involving improved means of waste disposal and environmental hygiene. Moreover, cancer in fish indicates that this important food source may be contaminated. Detection of genotoxic carcinogens to which fish are exposed can be achieved quickly and efficiently by carefully selected batteries of complementary in vitro and in vivo bioassays. One such battery consists of the Ames test, a reverse mutation assay in prokaryotic Salmonella typhimurium, and the Williams test, involving DNA repair in freshly explanted metabolically highly competent liver cells from diverse species, including humans. Determination of DNA-carcinogen adducts by varied techniques, including 32P-postlabeling, as well as DNA breakage, mammalian cell mutagenicity, chromosome aberrations, sister chromatid exchange, or cell transformation represent additional approaches, each with its own advantages and disadvantages. More research is needed on systems to apprehend neoplasm promoters, but tests to determine interruption of intercellular communications through gap junctions appear promising. Other approaches rely on measurement of enzymes such as ornithine decarboxylase and protein kinase C. Approaches to the definition of risk to fish or humans require characterization of the genotoxic or nongenotoxic properties of a chemical, relative potency data obtained in select, limited rodent bioassays, and knowledge of prevailing environmental concentrations of specific carcinogens.

  19. 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...

  20. 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...

  1. Nitrites and nitrates in the human diet: Carcinogens or beneficial hypotensive agents?

    Science.gov (United States)

    Butler, Anthony

    2015-06-05

    The presence of nitrite in the human diet was thought to constitute a hazard as secondary nitrosamines are known to cause gastric cancers. Recent publications on the physiology of serum nitrite have been consulted. Nitrite is added to some foodstuffs as an antibotulinum agent. The epidemiological evidence that nitrite causes gastric ulcers is weak. On the other hand, evidence that the presence of nitrite in serum lowers blood pressure is strong. This allows us to explain why a Tang dynasty treatment for angina, given in a Dunhuang medical manuscript, can be successful. The presence of nitrite in food is free of danger and a diet high in nitrate is beneficial to the health. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  2. Research results from inquiries into the carcinogenic effects of surface active agents. On the non-hazardous nature of ABS

    Energy Technology Data Exchange (ETDEWEB)

    Toyama, Shinichi

    1963-03-15

    Although the trial-production alkylbenzene used behaved atypically and so is presumed to contain complex carcinogenic hydrocarbon-like impurity by-products, commercially available alkylbenzenes generally did not possess carcinogenic properties. These substances used in alkylbenzene sulfonate production have very small promotive characteristics comparable to croton oil. However, alkylbenzene sulfonate demonstrated no cancer producing properties. (DT)

  3. Direct spectral analysis and determination of high content of carcinogenic bromine in bread using UV pulsed laser induced breakdown spectroscopy.

    Science.gov (United States)

    Mehder, A O; Gondal, Mohammed A; Dastageer, Mohamed A; Habibullah, Yusuf B; Iqbal, Mohammed A; Oloore, Luqman E; Gondal, Bilal

    2016-01-01

    Laser induced breakdown spectroscopy (LIBS) was applied for the detection of carcinogenic elements like bromine in four representative brands of loaf bread samples and the measured bromine concentrations were 352, 157, 451, and 311 ppm, using Br I (827.2 nm) atomic transition line as the finger print atomic transition. Our LIBS system is equipped with a pulsed laser of wavelength 266 nm with energy 25 mJ pulse(-1), 8 ns pulse duration, 20 Hz repetition rate, and a gated ICCD camera. The LIBS system was calibrated with the standards of known concentrations in the sample (bread) matrix and such plot is linear in 20-500 ppm range. The capability of our system in terms of limit of detection and relative accuracy with respect to the standard inductively coupled plasma mass spectrometry (ICPMS) technique was evaluated and these values were 5.09 ppm and 0.01-0.05, respectively, which ensures the applicability of our system for Br trace level detection, and LIBS results are in excellent agreement with that of ICPMS results.

  4. In vitro transformation: interactions of chemical carcinogens and radiation

    International Nuclear Information System (INIS)

    DiPaolo, J.A.

    1976-01-01

    The development of reproducible quantitative in vitro procedures resulting in neoplastic transformation of mammalian cells has made possible the separation of events related to the process leading to transformation from secondary events that interfere with the early recognition of transformation. The use of chemical carcinogens on Syrian hamster cell strains results in a dose-response relation consistent with a Poisson distribution, indicating that the transformation phenomenon is inductive. In some circumstances, the joint action or interaction of chemical carcinogens with other agents results in an increased incidence of transformation. The pretreatment of Syrian hamster cells with ionizing radiation (250 R) or alkylating chemicals enhances the frequency of transformation on a cell or colony basis ordinarily obtained with known chemical carcinogens. Pretreatment with non-ionizing irradiation (uv, 254 nm) did not have a similar effect. The two types of irradiation and the alkylating agents reduced the cloning efficiency of the cells. X ray alone produced no transformation; the alkylating chemicals produced transformations infrequently, whereas uv produced a significant number of transformations. The number of transformations associated with uv is increased by pretreatment of the cells by x-irradiation. The enhancement of transformation by x-ray or x-ray-type agents appears to be independent of the type of second carcinogen used

  5. 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

  6. 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.

  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. Smoking out carcinogens

    OpenAIRE

    Baines, David; Griffiths, Huw; Parker, Jane

    2016-01-01

    Smoked foods are becoming increasingly popular and are being produced by large and small food operations, artisan producers, chefs and consumers themselves. Epidemiological studies conducted over a number of decades have linked the consumption of smoked foods with various cancers and these findings have been supported by animal testing. Smoke contains a group of dangerous carcinogens that are responsible for lung cancer in cigarette smokers and implicated as causative agents for colorectal an...

  9. Comparison of UV irradiation and p-fluorphenylaline as selective agents for production of aromatic compounds in plant cell culture

    International Nuclear Information System (INIS)

    Quesnel, A.A.; Ellis, B.E.

    1989-01-01

    Resistance to UV irradiation, and to the toxicity of p-fluorophenylalanine, can both be mediateted in plants by enhanced synthesis of aromatic compounds. These selective agents were applied to cell cultures of Nicotiana tabacum, Anchusa officinalis and Catharanthus roseur, and the production of aromatic metabolites in the resulting resistant lines of each species was compared. While Nicotiana and Anchusa cultures responded to each selective agent ith an enhanced accumulation of aromatic compounds, the Catharanthus cultures acquired resistance through other, unknown, mechanisms. Some degree of cross-resistance was observed between cultures selected individually for resistance to each agent (author). 26 refs.; 2 figs.; 1 tab

  10. Reaction of a chemotherapeutic agent, 6-mercaptopurine, with a direct-acting, electrophilic carcinogen, benzo[a]pyrene-7,8-diol 9,10-epoxide.

    Science.gov (United States)

    MacLeod, M C; Stewart, E; Daylong, A; Lew, L K; Evans, F E

    1991-01-01

    The chemotherapeutic agent 6-mercaptopurine (6-MP) has been shown to react covalently with the ultimate carcinogenic metabolite of benzo[a]pyrene, 7-r,8-t-dihydroxy-9-t,10-t-oxy-7,8,9,10-tetrahydrobenzo[a]pyrene (BPDE), in aqueous solution, forming a single adduct. NMR studies of the HPLC-purified product were consistent with its identification as 10(S)-(6'-mercaptopurinyl)-7,8,9-trihydroxy-7,8,9,10- tetrahydrobenzo[a]pyrene. Reaction kinetics were analyzed by using both HPLC separation of the products formed and a spectrophotometric assay for adduct formation. A simple model in which direct reaction between 6-MP and BPDE takes place without formation of a physical complex was found to adequately predict the dependence of product ratios on 6-MP concentration. Variations in the observed rate constant for this reaction with changes in temperature, pH, and buffer concentration were determined and compared to the effects of these variables on the observed rate constant for BPDE hydrolysis. In each case, the processes were affected quite differently, suggesting that different rate-determining steps are involved. The data suggest that the reaction mechanism involves SN2 attack of the anion of 6-MP, formed by ionization of the sulfhydryl group, on carbon 10 of BPDE, resulting in a trans-9,10 reaction product.

  11. Enhanced mutagenicity of low doses of alkylating agents and UV-light by inhibition of ribonucleotide reductase

    International Nuclear Information System (INIS)

    Jenssen, D.

    1986-01-01

    Monofunctional alkylating agents and UV-light are potent inducers of gene mutations in mammalian cells. Most data on these agent are supporting the idea that 0/sup 6/-alkylguanine is the dominating lesion responsible for the mutations induced by the alkylating agents and thymine-dimers in the case of UV-light. However, little is known about the mutagenic fate of these lesions during the replicative process. This is an essential issue to investigate not the least because of quantitative aspects. By investigating the factors affecting the mutagenic yield of these lesions, they hope to get further information on the mechanisms(s) involved. To study this, a system was applied which involves synchronized V79 Chinese hamster cells and inhibitors of the replication process. By applying hydroxyurea (HU), as inhibitor of the ribonucleotide reductase (RNR) step in DNA synthesis, the effect of nucleotide pool imbalance has been studied at the HGPRT-locus using V79 Chinese hamster cells

  12. Effect of DNA repair on the cytotoxicity and mutagenicity of uv irradiation and of chemical carcinogens in normal and xeroderma pigmentosum cells

    International Nuclear Information System (INIS)

    Maher, V.M.; McCormick, J.J.

    1976-01-01

    The cytotoxic and mutagenic action of ultraviolet (UV) irradiation and of aromatic amides or polycyclic hydrocarbons was quantitatively compared in normally repairing strains of human cells and in several excision-repair deficient or post-replication repair-deficient xeroderma pigmentosum (XP) strains

  13. Preparation of O/I1-type Emulsions and S/I1-type Dispersions Encapsulating UV-Absorbing Agents.

    Science.gov (United States)

    Aramaki, Kenji; Kimura, Minami; Masuda, Kazuki

    2015-01-01

    Oil-in-cubic phase (O/I1) emulsions encapsulating the cosmetic UV absorbing agents 2-ethylhexyl 4-methoxycinnamate (EHMC), 2-ethylhexyl 2-cyano-3,3-diphenylacrylate (octocrylene, OCR) and 1-(4-tertbutylphenyl)-3-(4-methoxyphenyl)-1,3-propanedione (Avobenzone, TBMP) were prepared by vortex mixing accompanied by a heating-cooling process. A ternary phase diagram in a water/C12EO25/EHMC system at 25°C was constructed and the two-phase equilibrium of an oil phase and an I1 phase, which is necessary to prepare the O/I1-type emulsions, was confirmed. Also, the melting of the I1 phase into a fluid micellar solution phase was confirmed, allowing emulsification by a heating-cooling process. The O/I1-type emulsions were formulated in the ternary system as well as a quaternary system. The four-component system contained an additional cosolvent, isopropyl myristate (IPM). The use of the cosolvent allows the use of reduced amounts of EHMC, which is desirable because EHMC can cause temporary skin irritation. Formulation of the O/I1-type emulsions with other UV absorbing agents (OCR and TBMP) was also possible using the same emulsification method. When IPM was changed to tripalmitin, which has a melting point greater than room temperature, a solid-oil dispersion in I1 phase was formed. We have termed this a "solidin-cubic phase (S/I1) type dispersion". These novel emulsions have not been reported previously. The UV absorbability of the O/I1-type emulsions and S/I1-type dispersions that encapsulate the UV absorbing agents was confirmed by measurement of UV absorption spectra.

  14. Enhanced reactivation of UV-irradiated adenovirus 2 in HeLa cells treated with non-mutagenic chemical agents

    Energy Technology Data Exchange (ETDEWEB)

    Piperakis, S.M.; McLennan, A.G. (Liverpool Univ. (UK). Dept. of Biochemistry)

    1985-03-01

    Treatment of HeLa cells with ethanol and sodium arsenite, compounds which are known to elicit the heat-shock response, before infection with UV-irradiated adenovirus 2 has been found to result in the enhanced reactivation of the damaged virus in a manner similar to that obtained by pre-irradiation or heating of the cells. Enhanced reactivation may be the result of the inhibition of DNA synthesis caused by these agents since hydroxyurea also produced a significant enhancement.

  15. Oxidative Stress in the Carcinogenicity of Chemical Carcinogens

    International Nuclear Information System (INIS)

    Kakehashi, Anna; Wei, Min; Fukushima, Shoji; Wanibuchi, Hideki

    2013-01-01

    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 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

  16. 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.

  17. 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.

  18. Chemical carcinogens

    National Research Council Canada - National Science Library

    Searle, Charles E

    1976-01-01

    Cancer causing agents are now known to exist throughout the environment-in polluted air and tobacco smoke, in various plants and foods, and in many chemicals that are used in industry and laboratories...

  19. Mutagenic and carcinogenic properties of drinking water

    International Nuclear Information System (INIS)

    Kool, H.J.; van Kreijl, C.F.; Hrubec, J.

    1985-01-01

    In this chapter results of oxidation treatments with chlorine, ozone, chlorine dioxide, and ultraviolet (UV), with respect to their effects on activity (Ames test) in drinking water supplies are reviewed. In addition, the authors present the preliminary results of a pilot plant study on the effects of chlorine and chlorine dioxide on mutagenicity. Furthermore, results of several carcinogenicity studies performed with organic drinking water concentrates are discussed in relation to the results of a Dutch carcinogenicity study with mutagenic drinking water concentrates

  20. Treating cell culture media with UV irradiation against adventitious agents: minimal impact on CHO performance.

    Science.gov (United States)

    Yen, Sandi; Sokolenko, Stanislav; Manocha, Bhavik; Blondeel, Eric J M; Aucoin, Marc G; Patras, Ankit; Daynouri-Pancino, Farnaz; Sasges, Michael

    2014-01-01

    Sterility of cell culture media is an important concern in biotherapeutic processing. In large scale biotherapeutic production, a unit contamination of cell culture media can have costly effects. Ultraviolet (UV) irradiation is a sterilization method effective against bacteria and viruses while being non-thermal and non-adulterating in its mechanism of action. This makes UV irradiation attractive for use in sterilization of cell culture media. The objective of this study was to evaluate the effect of UV irradiation of cell culture media in terms of chemical composition and the ability to grow cell cultures in the treated media. The results showed that UV irradiation of commercial cell culture media at relevant disinfection doses impacted the chemical composition of the media with respect to several carboxylic acids, and to a minimal extent, amino acids. The cumulative effect of these changes, however, did not negatively influence the ability to culture Chinese Hamster Ovary cells, as evaluated by cell viability, growth rate, and protein titer measurements in simple batch growth compared with the same cells cultured in control media exposed to visible light. © 2014 The Authors. Published by Wiley Periodicals, Inc. on behalf of American Institute of Chemical Engineers.

  1. Carcinogenic effects of radiation-introduction

    International Nuclear Information System (INIS)

    Setlow, R.B.

    1976-01-01

    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

  2. In vitro study of cytotoxicity by U.V. radiation and differential sensitivity in combination with alkylating agents on established cell systems

    International Nuclear Information System (INIS)

    Ramudu, K.

    1991-01-01

    The effect of U.V. radiation or alkylating agents, such as actinomycin-D, cycloheximide and mitomycin-C (MMC), was studied on CHO, BHK and HeLa cells. U.V. radiation caused DNA ssb and dsb and were prevented by cycloheximide and actinomycin-D. MMC is known to be cytotoxic in CHO/BHK cells by forming free radical generation. MMC in combination with U.V. radiation enhanced DNA ssb ampersand dsb in these cell types. However, HeLa cells were insensitive to U.V. radiation. This insensitivity to U.V. radiation could be ascribed to the presence of glutathione transferase which is absent in CHO/BHK cell line

  3. 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.

  4. Biomarkers of carcinogen exposure and early effects.

    OpenAIRE

    2006-01-01

    The purpose of this review is to summarise the current situation regarding the types and uses of biomarkers of exposure and effect for the main classes of food-derived genotoxic carcinogens, and to consider some aspects of the intercomparison between these biomarkers. The biomarkers of exposure and early effects of carcinogens that have been most extensively developed are those for genotoxic agents and for compounds that generate hydroxyl radicals and other reactive radical species, and it is...

  5. 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.

  6. Sodium butyrate affects the cytotoxic and mutagenic response of V79 Chinese hamster cells to the genotoxic agents, daunorubicin and U.V. radiation

    International Nuclear Information System (INIS)

    Pani, B.; Babudri, N.; Giancotti, V.; Russo, E.

    1984-01-01

    It has been suggested that conditions which lead to modifications in the chromatin structure could be responsible for an increased accessibility of DNA to genotoxic agents in eukaryotic cells. With this in mind, the cytotoxic and mutagenic activity of the anthracycline antibiotic, daunorubicin, and of UV radiation was assayed on V79 Chinese hamster cells pretreated or not with 5 mM sodium butyrate, an agent known to induce modifications in the chromatin structure: this treatment in fact proved to induce the hyperacetylation of the core histones, and moreover to enhance the cytotoxic response of the cells to both daunorubicin and UV radiation and the mutagenic response to daunorubicin. (orig.)

  7. Biobased Nanoparticles for Broadband UV Protection with Photostabilized UV Filters

    NARCIS (Netherlands)

    Hayden, D.R.|info:eu-repo/dai/nl/412640694; Imhof, A.|info:eu-repo/dai/nl/145641600; Velikov, K. P.|info:eu-repo/dai/nl/239483472

    2016-01-01

    Sunscreens rely on multiple compounds to provide effective and safe protection against UV radiation. UV filters in sunscreens, in particular, provide broadband UV protection but are heavily linked to adverse health effects due to the generation of carcinogenic skin-damaging reactive oxygen species

  8. Cytotoxic and mutagenic effects of specific carcinogen-DNA adducts in diploid human fibroblasts

    International Nuclear Information System (INIS)

    McCormick, J.J.; Maher, V.M.

    1985-01-01

    A comparison of the cytotoxicity and mutagenicity of a series of carcinogens in normal diploid human fibroblasts and in cells deficient in one or more DNA repair processes has provided insight into the specific DNA adduct(s) responsible for these biological effects. The carcinogens tested include ultraviolet radiation; reactive derivatives of structurally related aromatic amides; metabolites of benzo(a)pyrene; the simple alkylating agents N-methyl-N'-nitro-N-nitrosoguanidine and N-ethyl-N-nitrosourea; and aflatoxin B 1 dichloride, a model for the reactive 2,3-epoxide of aflatoxin B 1 . Exponentially growing cells were exposed to agents and assayed for mutations and cell killing. Cells deficient in repair of particular DNA adducts or lesions proved more sensitive to the agent causing those lesions than did normally repairing cells. Many of the carcinogens were compared for their mutagenic and/or cytotoxic effect, not only as a function of dose administered, but also as a function of the initial number of adducts or photoproducts induced in DNA and the number remaining at critical times posttreatment. The results demonstrated a high correlation between the number of DNA lesions remaining unexcised at the time the DNA was replicated and frequency of mutations induced. Comparative studies of the frequency of UV-induced transformation of normal and repair-deficient cells showed this also to be true for transformation

  9. 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)

    Ljungman, Mats

    1989-01-01

    Confluent human fibroblast cultures were pretreated with either 254 nm UV light (UV) or methyl methanesulphonate (MMS), incubated at 37 0 C 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)

  10. 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.

  11. Evaluating the biological risk of functionalized multiwalled carbon nanotubes and functionalized oxygen-doped multiwalled carbon nanotubes as possible toxic, carcinogenic, and embryotoxic agents

    Directory of Open Access Journals (Sweden)

    Lara-Martínez LA

    2017-10-01

    evaluation of the transformation to cancer cells and cytotoxicity process showed little effect. However, we found a severe embryotoxicity in chicken embryos that were treated with fMWCNTs, while fCOxs seem to exert cardioembryotoxicity and a discrete teratogenicity. Furthermore, it seems that the time of contact plays an important role during cell transformation and embryotoxicity. A single contact with fMWCNTs is not sufficient to transform cells in a short time; an exposure of fMWCNTs for 2 weeks led to cell transformation risk and cardioembryotoxicity effects. Keywords: nanostructure, biocompatibility, scaffold, cell proliferation, cell cycle, carcinogenic

  12. The multitude and diversity of environmental carcinogens

    International Nuclear Information System (INIS)

    Belpomme, D.; Irigaray, P.; Hardell, L.; Clapp, R.; Montagnier, L.; Epstein, S.; Sasco, A.J.

    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 International Agency for Research on Cancer (IARC). We thus analyze the carcinogenic effect of microorganisms (including viruses), radiations (including radioactivity, UV and pulsed electromagnetic fields) and xenochemicals. Chemicals related to environmental pollution appear to be of critical importance, since they can induce occupational cancers as well as other cancers. Of major concerns are: outdoor air pollution by carbon particles associated with polycyclic aromatic hydrocarbons; indoor air pollution by environmental tobacco smoke, formaldehyde and volatile organic compounds such as benzene and 1,3 butadiene, which may particularly affect children, and food pollution by food additives and by carcinogenic contaminants such as nitrates, pesticides, dioxins and other organochlorines. In addition, carcinogenic metals and metalloids, pharmaceutical medicines and cosmetics may be involved. Although the risk fraction attributable to environmental factors is still unknown, this long list of carcinogenic and especially mutagenic factors supports our working hypothesis according to which numerous cancers may in fact be caused by the recent modification of our environment

  13. Dietary Carcinogens and Anticarcinogens.

    Science.gov (United States)

    Ames, Bruce N.

    1983-01-01

    Describes 16 mutagens/carcinogens found in plant food and coffee as well as several anticarcinogens also found in such food. Speculates on relevant biochemical mechanisms, particularly the role of oxygen radicals and their inhibitors in the fat/cancer relationship, promotion, anticarcinogenesis, and aging. (JN)

  14. Identifying occupational carcinogens: an update from the IARC Monographs.

    Science.gov (United States)

    Loomis, Dana; Guha, Neela; Hall, Amy L; Straif, Kurt

    2018-05-16

    The recognition of occupational carcinogens is important for primary prevention, compensation and surveillance of exposed workers, as well as identifying causes of cancer in the general population. This study updates previously published lists of known occupational carcinogens while providing additional information on cancer type, exposure scenarios and routes, and discussing trends in the identification of carcinogens over time. Data were extracted from International Agency for Research on Cancer (IARC) Monographs covering the years 1971-2017, using specific criteria to ensure occupational relevance and provide high confidence in the causality of observed exposure-disease associations. Selected agents were substances, mixtures or types of radiation classified in IARC Group 1 with 'sufficient evidence of carcinogenicity' in humans from studies of exposed workers and evidence of occupational exposure documented in the pertinent monograph. The number of known occupational carcinogens has increased over time: 47 agents were identified as known occupational carcinogens in 2017 compared with 28 in 2004. These estimates are conservative and likely underestimate the number of carcinogenic agents present in workplaces. Exposure to these agents causes a wide range of cancers; cancers of the lung and other respiratory sites, followed by skin, account for the largest proportion. The dominant routes of exposure are inhalation and dermal contact. Important progress has been made in identifying occupational carcinogens; nevertheless, there is an ongoing need for research on the causes of work-related cancer. Most workplace exposures have not been evaluated for their carcinogenic potential due to inadequate epidemiologic evidence and a paucity of quantitative exposure data. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  15. How many food additives are rodent carcinogens?

    Science.gov (United States)

    Johnson, F M

    2002-01-01

    One generally assumes that chemical agents added to foods are reasonably free of risks to human health, and practically everyone consumes some additives in his or her food daily throughout life. In the United States, the 1958 Food Additives Amendment to the Federal Food, Drug and Cosmetic Act of 1938 requires food manufacturers to demonstrate the safety of food additives to the Food and Drug Administration (FDA). The Amendment contains a provision that prohibits approval of an additive if it is found to cause cancer in humans or animals. In the present study, data from the National Toxicology Program rodent bioassay (NTPRB) were used to identify a sample of approximately 50 rodent-tested additives and other chemicals added to food that had been evaluated independently of the FDA/food industry. Surprisingly, the sample shows more than 40% of these food chemicals to be carcinogenic in one or more rodent groups. If this percentage is extrapolated to all substances added to food in the United States, it would imply that more than 1000 of such substances are potential rodent carcinogens. The NTP and FDA test guidelines use similar, though not necessarily identical, rodent test procedures, including near lifetime exposures to the maximum tolerated dose. The FDA specifies that test chemicals should be administered by the oral route. However, the oral route includes three methods of delivering chemicals, that is, mixed in the food or water or delivered by stomach tube (gavage). The NTP data show only 1 of 18 food chemicals mixed in the food are rodent carcinogens, but 16 of 23 gavage-administered food chemicals are carcinogenic to rodents. The distribution suggests that among orally delivered chemicals, those administered in the feed will more likely prove to be noncarcinogens than chemicals given by gavage. The rodent data also reveal that effects may vary according to dose and genotype, as well as by route of administration, to further complicate extrapolation to humans

  16. Carcinogen risk assessment

    International Nuclear Information System (INIS)

    Hazelwoold, R.N.

    1987-01-01

    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

  17. 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 were...... of the exocyclic amino group. Estimations of human cancer risk have indicated that ingestion of food containing aminoimidazoazaarenes are of importance....

  18. Chromium carcinogenicity: California strategies.

    Science.gov (United States)

    Alexeeff, G V; Satin, K; Painter, P; Zeise, L; Popejoy, C; Murchison, G

    1989-10-01

    Hexavalent chromium was identified by California as a toxic air contaminant (TAC) in January 1986. The California Department of Health Services (CDHS) concurred with the findings of the International Agency for Research on Cancer that there is sufficient evidence to demonstrate the carcinogenicity of chromium in both animals and humans. CDHS did not find any compelling evidence demonstrating the existence of a threshold with respect to chromium carcinogenesis. Experimental data was judged inadequate to assess potential human reproductive risks from ambient exposures. Other health effects were not expected to occur at ambient levels. The theoretically increased lifetime carcinogenic risk from a continuous lifetime exposure to hexavalent chromium fell within the range 12-146 cancer cases per nanogram hexavalent chromium per cubic meter of air per million people exposed, depending on the potency estimate used. The primary sources found to contribute significantly to the risk of exposure were chrome platers, chromic acid anodizing facilities and cooling towers utilizing hexavalent chromium as a corrosion inhibitor. Evaluation of genotoxicity data, animal studies and epidemiological studies indicates that further consideration should be given to the potential carcinogenicity of hexavalent chromium via the oral route.

  19. Immobilized WO3 nanoparticles on graphene oxide as a photo-induced antibacterial agent against UV-resistant Bacillus pumilus

    Science.gov (United States)

    Hosseini, Farshad; Rasuli, Reza; Jafarian, Vahab

    2018-04-01

    We present the antibacterial and photo-catalytic activity of immobilized WO3 nanoparticles on graphene oxide sheets. WO3 nanoparticles were immobilized on graphene oxide using the arc discharge method in arc currents of 5, 20, 40 and 60 A. Tauc plots of the UV-visible spectra show that the band gap of the prepared samples decreases (to ~2.7 eV) with respect to the WO3 nanoparticles. Photo-catalytic activity was examined by the degradation of rhodamine B under ultra-violet irradiation and the results show that the photo-catalytic activity of WO3 nanoparticles is increased by immobilizing them on graphene oxide sheets. In addition, the photo-degradation yield of the samples prepared by the 5 A arc current is 84% in 120 min, which is more than that of the other samples. The antibacterial activity of the prepared samples was studied against Bacillus pumilus (B. pumilus) bacteria, showing high resistance to ultra-violet exposure. Our results show that the bare and immobilized WO3 nanoparticles become more active under UV irradiation and their antibacterial properties are comparable with Ag nanoparticles. Besides this, the results show that although the photo-catalytic activity of the post-annealed samples at 500 °C is less than the as-prepared samples, it is, however, more active against B. pumilus bacteria under UV irradiation.

  20. Identification of Chemical Agents (Mimics) Residues after Destructive Adsorption Using TPD and UV-vis-IR and Raman

    National Research Council Canada - National Science Library

    Klabunde, Kenneth J

    2001-01-01

    Instrumentation was purchased that helps characterize the chemical structures and chemical reactions that occur when nanocrystalline metal oxides carry out destructive adsorption of chemical agents mimics. The residues (adducts...

  1. Response of human epidermal keratinocytes to UV light

    International Nuclear Information System (INIS)

    Kartasova, A.A.

    1987-01-01

    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

  2. METABOLISM, GENOTOXICITY, AND CARCINOGENICITY OF COMFREY

    Science.gov (United States)

    Mei, Nan; Guo, Lei; Fu, Peter P.; Fuscoe, James C.; Luan, Yang; Chen, Tao

    2018-01-01

    Comfrey has been consumed by humans as a vegetable and a tea and used as an herbal medicine for more than 2000 years. Comfrey, however, produces hepatotoxicity in livestock and humans and carcinogenicity in experimental animals. Comfrey contains as many as 14 pyrrolizidine alkaloids (PA), including 7-acetylintermedine, 7-acetyllycopsamine, echimidine, intermedine, lasiocarpine, lycopsamine, myoscorpine, symlandine, symphytine, and symviridine. The mechanisms underlying comfrey-induced genotoxicity and carcinogenicity are still not fully understood. The available evidence suggests that the active metabolites of PA in comfrey interact with DNA in liver endothelial cells and hepatocytes, resulting in DNA damage, mutation induction, and cancer development. Genotoxicities attributed to comfrey and riddelliine (a representative genotoxic PA and a proven rodent mutagen and carcinogen) are discussed in this review. Both of these compounds induced similar profiles of 6,7-dihydro-7-hydroxy-1-hydroxymethyl-5H-pyrrolizine (DHP)-derived DNA adducts and similar mutation spectra. Further, the two agents share common mechanisms of drug metabolism and carcinogenesis. Overall, comfrey is mutagenic in liver, and PA contained in comfrey appear to be responsible for comfrey-induced toxicity and tumor induction. PMID:21170807

  3. Metabolism, genotoxicity, and carcinogenicity of comfrey.

    Science.gov (United States)

    Mei, Nan; Guo, Lei; Fu, Peter P; Fuscoe, James C; Luan, Yang; Chen, Tao

    2010-10-01

    Comfrey has been consumed by humans as a vegetable and a tea and used as an herbal medicine for more than 2000 years. Comfrey, however, produces hepatotoxicity in livestock and humans and carcinogenicity in experimental animals. Comfrey contains as many as 14 pyrrolizidine alkaloids (PA), including 7-acetylintermedine, 7-acetyllycopsamine, echimidine, intermedine, lasiocarpine, lycopsamine, myoscorpine, symlandine, symphytine, and symviridine. The mechanisms underlying comfrey-induced genotoxicity and carcinogenicity are still not fully understood. The available evidence suggests that the active metabolites of PA in comfrey interact with DNA in liver endothelial cells and hepatocytes, resulting in DNA damage, mutation induction, and cancer development. Genotoxicities attributed to comfrey and riddelliine (a representative genotoxic PA and a proven rodent mutagen and carcinogen) are discussed in this review. Both of these compounds induced similar profiles of 6,7-dihydro-7-hydroxy-1-hydroxymethyl-5H-pyrrolizine (DHP)-derived DNA adducts and similar mutation spectra. Further, the two agents share common mechanisms of drug metabolism and carcinogenesis. Overall, comfrey is mutagenic in liver, and PA contained in comfrey appear to be responsible for comfrey-induced toxicity and tumor induction.

  4. 39-week carcinogenicity study with cyclosporin A in XPA-/- mice, wild type mice and XPA-/-.P53+/- double transgenic mice. Part of the ILSI/HESI Program on Alternative Methods for Carcinogenicity Testing

    NARCIS (Netherlands)

    Beems RB; Kreijl CF van; Steeg H van; LPI; LEO

    2002-01-01

    The objective of this study was to evaluate the carcinogenic response of cyclosporin A in XPA-/- mice having a C57BL/6 background. XPA-/- mice are deficient in nucleotide excision repair and have shown increased susceptibility to genotoxic carcinogens and uv-light. The study was part of a world-wide

  5. Blood proteins as carcinogen dosimeters

    International Nuclear Information System (INIS)

    Tannenbaum, S.R.; Skipper, P.L.

    1986-01-01

    The problem of quantifying exposure to genotoxins in a given individual represents a formidable challenge. In this paper methods which rely on the covalent binding of carcinogens and their metabolites to blood proteins are described. That carcinogens interact with proteins as well as with DNA has been established, although whether protein-carcinogen adducts can result in genetic damage has not been established. It has been shown, however, that the amount of a protein carcinogen adduct formed may be used as a quantitative measure of exposure to a carcinogen. Such a measure presumably is reflective of the absorption, metabolism, and excretion of the compound in an exposed individual. Protein adduction may reflect exposure in a time-frame of weeks to months. Thus, protein adduct measurement is a form of human chemical dosimetry. Hemoglobin and albumin are promising candidates for such dosimeters. Hemoglobin has a lifetime of about 120 days in humans; thus, circulating levels of carcinogen-modified hemoglobin will reflect the level of carcinogen exposure during a period of nearly four months. It also possesses some metabolic competence, particularly, the ability to oxidize aromatic hydroxylamines to nitroso compounds which react quite efficiently with sulfhydryl groups. Albumin has a half-life of 20 to 25 days in man. This protein does not possess metabolic capacity other than, perhaps, some esterase activity. In contrast to hemoglobin, though, it is not protected by the erythrocyte membrane and might be the target for a greater number of carcinogens. It is present and is synthesized in the same cells in which the reactive metabolic intermediates of carcinogens are mostly formed - the hepatocytes. Also, albumin has a number of high-affinity binding sites for a broad spectrum of xenobiotics and endobiotics. 25 refs., 1 tab

  6. Efficacy of Inactivation of Human Enteroviruses by Multiple-Wavelength UV LEDs - abstract

    Science.gov (United States)

    Background: Ultraviolet (UV) light has been successfully used for treating a broad suite of pathogens without the concomitant formation of carcinogenic disinfection by-products (DBPs). However, conventional mercury UV lamps have some practical limitations in water treatment appli...

  7. Efficacy of Inactivation of Human Enteroviruses by Multiple-Wavelength UV LEDs

    Science.gov (United States)

    Ultraviolet (UV) light has been successfully used for treating a broad suite of pathogens without the concomitant formation of carcinogenic disinfection by-products (DBPs). However, conventional mercury UV lamps have some practical limitations in water treatment applications, suc...

  8. Carcinogenicity of soil extracts

    Energy Technology Data Exchange (ETDEWEB)

    Shcherbak, N P

    1970-01-01

    A total of 270 3-mo-old mice, hybrids of the C57BL and CBA strains which are highly susceptible to carcinogens, were painted on the skin (2-3 admin./week) with 3-4 drops of (1) a concentrated benzene extract of soil taken near a petroleum refinery with a 3,4 benzpyrene (BP) content of 0.22%; (2) a 0.22% soln of pure BP in benzene; (3) a concentrated benzene extract of soil taken from an old residential area of Moscow (BP content 0.0004%); (4) a 0.0004% BP soln in benzene; and (5) pure benzene. Only mice in the first 2 groups developed tumors. In group (1), 8 mice had papillomas, 46 had skin cancer, 1 had a sarcoma and 2 had plasmocytomas. In group (2) all 60 animals had skin cancer. Lung metastases were present at autopsy in 5 mice in group (1) and in 10 mice in group (2); in some cases, these tumors were multiple. Lymph node metastases were found in 6 mice in group (1) and in 10 mice in group (2). Tumors developed more slowly in group (1) than in group (2).

  9. 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). © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  10. 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 ...

  11. 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

  12. uvsI mutants defective in UV mutagenesis define a fourth epistatic group of uvs genes in Aspergillus.

    Science.gov (United States)

    Chae, S K; Kafer, E

    1993-01-01

    Three UV-sensitive mutations of A. nidulans, uvsI, uvsJ and uvsA, were tested for epistatic relationships with members of the previously established groups, here called the "UvsF", "UvsC", and "UvsB" groups. uvsI mutants are defective for spontaneous and induced reversion of certain point mutations and differ also for other properties from previously analyzed uvs types. They are very sensitive to the killing effects of UV-light and 4-NQO (4-nitro-quinoline-N-oxide) but not to MMS (methylmethane sulfonate). When double- and single-mutant uvs strains were compared for sensitivity to these three agents, synergistic or additive effects were found for uvsI with all members of the three groups. The uvsI gene may therefore represent a fourth epistatic group, possibly involved in mutagenic repair. On the other hand, uvsJ was clearly epistatic with members of the UvsF group and fitted well into this group also by phenotype. The uvsA gene was tentatively assigned to the UvsC group. uvsA showed epistatic interactions with uvsC in all tests, and like UvsC-group mutants is UV-sensitive mainly in dividing cells. However, the uvsA mutation does not cause the defects in recombination and UV mutagenesis typical for this group.

  13. Design, synthesis and biological evaluation of novel hydroxy-phenyl-1H-benzimidazoles as radical scavengers and UV-protective agents.

    Science.gov (United States)

    Bino, Alessia; Baldisserotto, Anna; Scalambra, Emanuela; Dissette, Valeria; Vedaldi, Daniela Ester; Salvador, Alessia; Durini, Elisa; Manfredini, Stefano; Vertuani, Silvia

    2017-12-01

    An ever-increasing incidence of skin neoplastic diseases is registered. Therefore, it is important to protect the skin from the UV radiation that reaches the epidermis and dermis but also to block ROS generated by them. Our attention was attracted in developing new compounds provided with both UV filtering and antioxidant capacities. To this end, 2-phenyl-1H-benzimidazole-5-sulfonic acid (PBSA), a known UV filter, was selected as lead compound for its lack of antioxidant activity, high water solubility and good safety profile. PBSA was sequentially modified introducing hydroxyls on the phenyl ring and also substituting the functional group in position 5 of the benzimidazole ring. At the end of the synthetic study, a new, very potent class of antioxidants has been obtained. Surprisingly some of the developed molecules, while devoid of significant UV-filtering activity was endowed with potent UV-filtering booster capability if associated with known commercial UVB and UVA filters.

  14. Carcinogen susceptibility is regulated by genome architecture and predicts cancer mutagenesis.

    Science.gov (United States)

    García-Nieto, Pablo E; Schwartz, Erin K; King, Devin A; Paulsen, Jonas; Collas, Philippe; Herrera, Rafael E; Morrison, Ashby J

    2017-10-02

    The development of many sporadic cancers is directly initiated by carcinogen exposure. Carcinogens induce malignancies by creating DNA lesions (i.e., adducts) that can result in mutations if left unrepaired. Despite this knowledge, there has been remarkably little investigation into the regulation of susceptibility to acquire DNA lesions. In this study, we present the first quantitative human genome-wide map of DNA lesions induced by ultraviolet (UV) radiation, the ubiquitous carcinogen in sunlight that causes skin cancer. Remarkably, the pattern of carcinogen susceptibility across the genome of primary cells significantly reflects mutation frequency in malignant melanoma. Surprisingly, DNase-accessible euchromatin is protected from UV, while lamina-associated heterochromatin at the nuclear periphery is vulnerable. Many cancer driver genes have an intrinsic increase in carcinogen susceptibility, including the BRAF oncogene that has the highest mutation frequency in melanoma. These findings provide a genome-wide snapshot of DNA injuries at the earliest stage of carcinogenesis. Furthermore, they identify carcinogen susceptibility as an origin of genome instability that is regulated by nuclear architecture and mirrors mutagenesis in cancer. © 2017 The Authors.

  15. Understanding arsenic carcinogenicity by the use of animal models

    International Nuclear Information System (INIS)

    Wanibuchi, Hideki; Salim, Elsayed I.; Kinoshita, Anna; Shen Jun; Wei Min; Morimura, Keiichirou; Yoshida, Kaoru; Kuroda, Koichi; Endo, Ginji; Fukushima, Shoji

    2004-01-01

    Although numerous epidemiological studies have indicated that human arsenic exposure is associated with increased incidences of bladder, liver, skin, and lung cancers, limited attempts have been made to understand mechanisms of carcinogenicity using animal models. Dimethylarsinic acid (DMA), an organic arsenic compound, is a major metabolite of ingested inorganic arsenics in mammals. Recent in vitro studies have proven DMA to be a potent clastogenic agent, capable of inducing DNA damage including double strand breaks and cross-link formation. In our attempts to clarify DMA carcinogenicity, we have recently shown carcinogenic effects of DMA and its related metabolites using various experimental protocols in rats and mice: (1) a multi-organ promotion bioassay in rats; (2) a two-stage promotion bioassay by DMA of rat urinary bladder and liver carcinogenesis; (3) a 2-year carcinogenicity test of DMA in rats; (4) studies on the effects of DMA on lung carcinogenesis in rats; (5) promotion of skin carcinogenesis by DMA in keratin (K6)/ornithine decarboxylase (ODC) transgenic mice; (6) carcinogenicity of DMA in p53(+/-) knockout and Mmh/8-OXOG-DNA glycolase (OGG1) mutant mice; (7) promoting effects of DMA and related organic arsenicals in rat liver; (8) promoting effects of DMA and related organic arsenicals in a rat multi-organ carcinogenesis test; and (9) 2-year carcinogenicity tests of monomethylarsonic acid (MMA) and trimethylarsine oxide (TMAO) in rats. The results revealed that the adverse effects of arsenic occurred either by promoting and initiating carcinogenesis. These data, as covered in the present review, suggest that several mechanisms may be involved in arsenic carcinogenesis

  16. The effects of environmental chemical carcinogens on the microRNA machinery.

    Science.gov (United States)

    Izzotti, A; Pulliero, A

    2014-07-01

    The first evidence that microRNA expression is early altered by exposure to environmental chemical carcinogens in still healthy organisms was obtained for cigarette smoke. To date, the cumulative experimental data indicate that similar effects are caused by a variety of environmental carcinogens, including polycyclic aromatic hydrocarbons, nitropyrenes, endocrine disruptors, airborne mixtures, carcinogens in food and water, and carcinogenic drugs. Accordingly, the alteration of miRNA expression is a general mechanism that plays an important pathogenic role in linking exposure to environmental toxic agents with their pathological consequences, mainly including cancer development. This review summarizes the existing experimental evidence concerning the effects of chemical carcinogens on the microRNA machinery. For each carcinogen, the specific microRNA alteration signature, as detected in experimental studies, is reported. These data are useful for applying microRNA alterations as early biomarkers of biological effects in healthy organisms exposed to environmental carcinogens. However, microRNA alteration results in carcinogenesis only if accompanied by other molecular damages. As an example, microRNAs altered by chemical carcinogens often inhibits the expression of mutated oncogenes. The long-term exposure to chemical carcinogens causes irreversible suppression of microRNA expression thus allowing the transduction into proteins of mutated oncogenes. This review also analyzes the existing knowledge regarding the mechanisms by which environmental carcinogens alter microRNA expression. The underlying molecular mechanism involves p53-microRNA interconnection, microRNA adduct formation, and alterations of Dicer function. On the whole, reported findings provide evidence that microRNA analysis is a molecular toxicology tool that can elucidate the pathogenic mechanisms activated by environmental carcinogens. Copyright © 2014 Elsevier GmbH. All rights reserved.

  17. 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...

  18. Epigenetic alterations induced by genotoxic occupational and environmental human chemical carcinogens: A systematic literature review

    Science.gov (United States)

    Chappell, Grace; Pogribny, Igor P.; Guyton, Kathryn Z.; Rusyn, Ivan

    2016-01-01

    Accumulating evidence suggests that epigenetic alterations play an important role in chemically-induced carcinogenesis. Although the epigenome and genome may be equally important in carcinogenicity, the genotoxicity of chemical agents and exposure-related transcriptomic responses have been more thoroughly studied and characterized. To better understand the evidence for epigenetic alterations of human carcinogens, and the potential association with genotoxic endpoints, we conducted a systematic review of published studies of genotoxic carcinogens that reported epigenetic endpoints. Specifically, we searched for publications reporting epigenetic effects for the 28 agents and occupations included in Monograph Volume 100F of the International Agency for the Research on Cancer (IARC) that were classified as “carcinogenic to humans” (Group 1) with strong evidence of genotoxic mechanisms of carcinogenesis. We identified a total of 158 studies that evaluated epigenetic alterations for 12 of these 28 carcinogenic agents and occupations (1,3-butadiene, 4-aminobiphenyl, aflatoxins, benzene, benzidine, benzo[a]pyrene, coke production, formaldehyde, occupational exposure as a painter, sulfur mustard, and vinyl chloride). Aberrant DNA methylation was most commonly studied, followed by altered expression of non-coding RNAs and histone changes (totaling 85, 59 and 25 studies, respectively). For 3 carcinogens (aflatoxins, benzene and benzo[a]pyrene), 10 or more studies reported epigenetic effects. However, epigenetic studies were sparse for the remaining 9 carcinogens; for 4 agents, only 1 or 2 published reports were identified. While further research is needed to better identify carcinogenesis-associated epigenetic perturbations for many potential carcinogens, published reports on specific epigenetic endpoints can be systematically identified and increasingly incorporated in cancer hazard assessments. PMID:27234561

  19. UV-induced skin damage

    International Nuclear Information System (INIS)

    Ichihashi, M.; Ueda, M.; Budiyanto, A.; Bito, T.; Oka, M.; Fukunaga, M.; Tsuru, K.; Horikawa, T.

    2003-01-01

    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

  20. Comparison of the dose-effect relationship for UV radiation and ionizing radiation

    International Nuclear Information System (INIS)

    Leenhouts, H.P.; Sijsma, M.J.; Chadwick, K.H.

    1990-06-01

    Ionizing radiation and ultraviolet radiation (UV) are both physical agents with mutagenic and carcinogenic properties. However, there are some basic differences in the fundamental mechanism of their interaction with biological material that may have consequences for risk assessment. In this paper the dose-effect relationships for gamma radiation and UV at cellular level will be used to demonstrate the different radio-biological effectiveness of both agents. The results will be discussed in the framework of a biophysical model, based on the assumption that DNA doublestranded lesions are crucial for the cytotoxic action. After exposure to ionizing radiation, the lesions are fixed immediately following irradiation, but after UV exposure the lethal lesions are recognized only in the next DNA synthesis phase. The combination of this concept with the mechanism of lesion induction and the possibility of repair, leads to different dose and time relationships for the radiation effects of both agents. The possible consequences for risk assessment at low levels will be discussed. (author). 9 refs.; 5 figs

  1. 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.

  2. UvA Rescue - Team Description Paper - Agent competition - Rescue Simulation League RoboCup 2014 - João Pessoa - Brazil

    NARCIS (Netherlands)

    Traichioiu, M.; Visser, A.

    2014-01-01

    This year's contribution of the UvA Rescue Team is twofold. On one hand a theoretical contribution is made by describing the planning and coordination problem formally as an POMDP problem, which will allow to apply POMDP-solution methods in this application area. On the other hand the impact of the

  3. Depletion of mammalian O6-alkylguanine-DNA alkyltransferase activity by O6-benzylguanine provides a means to evaluate the role of this protein in protection against carcinogenic and therapeutic alkylating agents

    International Nuclear Information System (INIS)

    Dolan, M.E.; Pegg, A.E.; Moschel, R.

    1990-01-01

    O 6 -Alkylguanine-DNA alkyltransferase was rapidly and irreversibly inactivated by exposure to O 6 -benzylguanine or the p-chlorobenzyl and p-methylbenzyl analogues. This inactivation was much more rapid than with O 6 -methylguanine: incubation with 2.5 μM O 6 -benzylguanine led to more than a 90% loss of activity within 10 min, whereas 0.2 mM O 6 -methylguanine for 60 min was required for the same reduction. O 6 -Benzylguanine was highly effective in depleting the alkyltransferase activity of cultured human colon tumor (HT29) cells. Complete loss of activity was produced within 15 min after addition of O 6 -benzylguanine to the culture medium and a maximal effect was obtained with 5 μM. In contrast, at least 100 μM O 6 -methylguanine for 4 hr was needed to get a maximal effect, and this reduced the alkyltransferase by only 80%. Pretreatment of HT29 cells with 10 μM O 6 -benzylguanine for 2 hr led to a dramatic increase in the cytotoxicity produced by the chemotherapeutic agents 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU) or 2-chloroethyl(methylsulfonyl)methanesulfonate (Clomesone). Administration of O 6 -benzylguanine to mice at a dose of 10 mg/kg reduced alkyltransferase levels by more than 95% in both liver and kidney. These results indicate that depletion of the alkyltransferase by O 6 -benzylguanine may be used to investigate the role of the DNA repair protein in carcinogenesis and mutagensis and that this treatment may be valuable to increase the chemotherapeutic effectiveness of chloroethylating agents

  4. Skin β-Endorphin Mediates Addiction to UV Light

    OpenAIRE

    Fell, Gillian L.; Robinson, Kathleen C.; Mao, Jianren; Woolf, Clifford J.; Fisher, David E.

    2014-01-01

    Ultraviolet light is an established carcinogen yet evidence suggests that UV-seeking behavior has addictive features. Following UV exposure, epidermal keratinocytes synthesize Proopiomelanocortin that is processed to Melanocyte Stimulating Hormone, inducing tanning. We show that in rodents another POMC-derived peptide, β-endorphin, is coordinately synthesized in skin, elevating plasma levels after low-dose UV. Increases in pain-related thresholds are observed, and reversed by pharmacologic op...

  5. Risk Assessment Approaches for Carcinogenic Food Contaminants

    OpenAIRE

    Gillespie, Zoe; Pulido, Olga; Vavasour, Elizabeth

    2011-01-01

    Health Canada has identified the need for a standardized department-wide approach for the risk assessment of carcinogens in foods (e.g., pesticides, food chemical contaminants, veterinary therapeutics). A standardized approach would better facilitate and inform risk management strategies for the control of human exposure to food sources of carcinogens. Within the post- market regulatory context, directly DNA-reactive carcinogens are of most concern because any exposure is theoretically assume...

  6. 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

    International Nuclear Information System (INIS)

    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 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

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

    International Nuclear Information System (INIS)

    Thielmann, H.W.; Hecht, R.

    1980-01-01

    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) 2 ONFln, 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.) [de

  8. Carcinogenicity and mutagenicity of chromium.

    Science.gov (United States)

    Léonard, A; Lauwerys, R R

    1980-11-01

    Occupational exposure represents the main source of human contamination by chromium. For non-occupationally exposed people the major environmental exposure to chromium occurs as a consequence of its presence in food. Chromium must be considered as an essential element. Its deficiency impairs glucose metabolism. Trivalent chromium salts are poorly absorbed through the gastro-intestinal and respiratory tracts because they do not cross membranes easily. Hexavalent chromium can be absorbed by the oral and pulmonary routes and probably also through the skin. After its absorption, hexavalent chromium is rapidly reduced to the trivalent form which is probably the only form to be found in biological material. Epidemiological studies have shown that some chromium salts (mainly the slightly soluble hexavalent salts) are carcinogens. Lung cancers have, indeed, often been reported among workers in chromate-producing industry and, to a lesser extent, in workers from the chrome-pigment industry. The first attempts to produce cancers in experimental animals by inhalation or parenteral introduction gave negative or equivocal results but, from 1960, positive results have been obtained with various chromium compounds. As for the carcinogenic activity, the mutagenicity of chromium has mainly been found with hexavalent salts. In the majority of assay systems used, trivalent chromium appears inactive. It can be considered as evident, however, that the ultimate mutagen which binds to the genetic material is the trivalent form produced intracellularly from hexavalent chromium, the apparent lack of activity of the trivalent form being due to its poor cellular uptake.

  9. Sum frequency generation and catalytic reaction studies of the removal of the organic capping agents from Pt nanoparticles by UV-ozone treatment

    Energy Technology Data Exchange (ETDEWEB)

    Aliaga, Cesar; Park, Jeong Y.; Yamada, Yusuke; Lee, Hyun Sook; Tsung, Chia-Kuang; Yang, Peidong; Somorjai, Gabor A.

    2009-12-10

    We report the structure of the organic capping layers of platinum colloid nanoparticles and their removal by UV-ozone exposure. Sum frequency generation vibrational spectroscopy (SFGVS) studies identify the carbon-hydrogen stretching modes on poly(vinylpyrrolidone) (PVP) and tetradecyl tributylammonium bromide (TTAB)-capped platinum nanoparticles. We found that the UV-ozone treatment technique effectively removes the capping layer on the basis of several analytical measurements including SFGVS, X-ray photoelectron spectroscopy, and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). The overall shape of the nanoparticles was preserved after the removal of capping layers, as confirmed by transmission electron microscopy (TEM). SFGVS of ethylene hydrogenation on the clean platinum nanoparticles demonstrates the existence of ethylidyne and di-{sigma}-bonded species, indicating the similarity between single-crystal and nanoparticle systems.

  10. 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.

  11. On the International Agency for Research on Cancer classification of glyphosate as a probable human carcinogen.

    Science.gov (United States)

    Tarone, Robert E

    2018-01-01

    The recent classification by International Agency for Research on Cancer (IARC) of the herbicide glyphosate as a probable human carcinogen has generated considerable discussion. The classification is at variance with evaluations of the carcinogenic potential of glyphosate by several national and international regulatory bodies. The basis for the IARC classification is examined under the assumptions that the IARC criteria are reasonable and that the body of scientific studies determined by IARC staff to be relevant to the evaluation of glyphosate by the Monograph Working Group is sufficiently complete. It is shown that the classification of glyphosate as a probable human carcinogen was the result of a flawed and incomplete summary of the experimental evidence evaluated by the Working Group. Rational and effective cancer prevention activities depend on scientifically sound and unbiased assessments of the carcinogenic potential of suspected agents. Implications of the erroneous classification of glyphosate with respect to the IARC Monograph Working Group deliberative process are discussed.

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

    International Nuclear Information System (INIS)

    Bittel, R.

    1987-07-01

    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 [fr

  13. Environmental exposure to carcinogens in northwestern Cameroon

    African Journals Online (AJOL)

    EB

    2013-09-03

    Sep 3, 2013 ... Twenty-nine (69.0%) [95% CI: 47.0 – 75.0] participants could smell the carcinogenic chemicals they use. Thirty. (71.4%) [95% CI: 65.0 – 77.0] participants had been instructed in the use of protective equipment against carcinogens. Participants used preventive devices like hand gloves, laboratory coats, ...

  14. Risk assessment of carcinogens in food

    International Nuclear Information System (INIS)

    Barlow, Susan; Schlatter, Josef

    2010-01-01

    Approaches for the risk assessment of carcinogens in food have evolved as scientific knowledge has advanced. Early methods allowed little more than hazard identification and an indication of carcinogenic potency. Evaluation of the modes of action of carcinogens and their broad division into genotoxic and epigenetic (non-genotoxic, non-DNA reactive) carcinogens have played an increasing role in determining the approach followed and provide possibilities for more detailed risk characterisation, including provision of quantitative estimates of risk. Reliance on experimental animal data for the majority of risk assessments and the fact that human exposures to dietary carcinogens are often orders of magnitude below doses used in experimental studies has provided a fertile ground for discussion and diverging views on the most appropriate way to offer risk assessment advice. Approaches used by national and international bodies differ, with some offering numerical estimates of potential risks to human health, while others express considerable reservations about the validity of quantitative approaches requiring extrapolation of dose-response data below the observed range and instead offer qualitative advice. Recognising that qualitative advice alone does not provide risk managers with information on which to prioritise the need for risk management actions, a 'margin of exposure' approach for substances that are both genotoxic and carcinogenic has been developed, which is now being used by the World Health Organization and the European Food Safety Authority. This review describes the evolution of risk assessment advice on carcinogens and discusses examples of ways in which carcinogens in food have been assessed in Europe.

  15. Risk assessment of carcinogens in food.

    Science.gov (United States)

    Barlow, Susan; Schlatter, Josef

    2010-03-01

    Approaches for the risk assessment of carcinogens in food have evolved as scientific knowledge has advanced. Early methods allowed little more than hazard identification and an indication of carcinogenic potency. Evaluation of the modes of action of carcinogens and their broad division into genotoxic and epigenetic (non-genotoxic, non-DNA reactive) carcinogens have played an increasing role in determining the approach followed and provide possibilities for more detailed risk characterisation, including provision of quantitative estimates of risk. Reliance on experimental animal data for the majority of risk assessments and the fact that human exposures to dietary carcinogens are often orders of magnitude below doses used in experimental studies has provided a fertile ground for discussion and diverging views on the most appropriate way to offer risk assessment advice. Approaches used by national and international bodies differ, with some offering numerical estimates of potential risks to human health, while others express considerable reservations about the validity of quantitative approaches requiring extrapolation of dose-response data below the observed range and instead offer qualitative advice. Recognising that qualitative advice alone does not provide risk managers with information on which to prioritise the need for risk management actions, a "margin of exposure" approach for substances that are both genotoxic and carcinogenic has been developed, which is now being used by the World Health Organization and the European Food Safety Authority. This review describes the evolution of risk assessment advice on carcinogens and discusses examples of ways in which carcinogens in food have been assessed in Europe.

  16. Environmental exposure to carcinogens in northwestern Cameroon ...

    African Journals Online (AJOL)

    African Health Sciences ... Humans can prevent themselves from a number of workplace and environmental carcinogens. ... Methods: A structured questionnaire was used to collect information on carcinogen exposure in the workplace and environment through trained field staff from volunteers after gaining informed ...

  17. Inconsistency... or why differentiate, where prevention is concerned, between radioactive substances and carcinogenic chemicals

    International Nuclear Information System (INIS)

    Choquet, R.; Vinit, J.

    1982-01-01

    Radiotracers, low-activity unsealed radioactive sources, and certain chemical products belong to the list of substances and agents known to promote cancers in humans. The dangers of radiotracers and carcinogenic chemicals being very similar, or even identical, it is inadmissible that preventive measures have not been equally developed and are not viewed in the same way in our country. It should be noted that the International Labour Bureau has long since included radioactive products in the list of carcinogenic substances and agents and treated preventive measures as a whole by proceeding in this way it would be easier to account for the possible combined effects of ionising radiations and chemical molecules. After a review of some facts about cancer the present situation is examined with regard to statutory measures applied on the one hand to radioelements and on the other to chemicals recognised as carcinogenic by international organisations. Proposals are made to remedy this illogical situation [fr

  18. Carcinogenicity of chromium and chemoprevention: a brief update

    Directory of Open Access Journals (Sweden)

    Wang Y

    2017-08-01

    Full Text Available Yafei Wang,1,* Hong Su,1,* Yuanliang Gu,1 Xin Song,1 Jinshun Zhao1,2 1Department of Preventative Medicine, Zhejiang Key Laboratory of Pathophysiology, School of Medicine, Ningbo University, Ningbo, People’s Republic of China; 2Toxicology and Molecular Biology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV, USA *These authors contributed equally to this work Abstract: Chromium has two main valence states: hexavalent chromium (Cr[VI] and trivalent chromium (Cr[III]. Cr(VI, a well-established human carcinogen, can enter cells by way of a sulfate/phosphate anion-transport system, and then be reduced to lower-valence intermediates consisting of pentavalent chromium (Cr[V], tetravalent chromium (Cr[IV] or Cr(III via cellular reductants. These intermediates may directly or indirectly result in DNA damage or DNA–protein cross-links. Although Cr(III complexes cannot pass easily through cell membranes, they have the ability to accumulate around cells to induce cell-surface morphological alteration and result in cell-membrane lipid injuries via disruption of cellular functions and integrity, and finally to cause DNA damage. In recent years, more research, including in vitro, in vivo, and epidemiological studies, has been conducted to evaluate the genotoxicity/carcinogenicity induced by Cr(VI and/or Cr(III compounds. At the same time, various therapeutic agents, especially antioxidants, have been explored through in vitro and in vivo studies for preventing chromium-induced genotoxicity/carcinogenesis. This review aims to provide a brief update on the carcinogenicity of Cr(VI and Cr(III and chemoprevention with different antioxidants. Keywords: hexavalent chromium, Cr(VI, trivalent chromium, Cr(III, genotoxicity, carcinogenicity, chemoprevention, antioxidant 

  19. 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.

  20. Application of the key characteristics of carcinogens in cancer hazard identification

    Science.gov (United States)

    Guyton, Kathryn Z; Rusyn, Ivan; Chiu, Weihsueh A; Corpet, Denis E; van den Berg, Martin; Ross, Matthew K; Christiani, David C; Beland, Frederick A; Smith, Martyn T

    2018-01-01

    Abstract Smith et al. (Env. Health Perspect. 124: 713, 2016) identified 10 key characteristics (KCs), one or more of which are commonly exhibited by established human carcinogens. The KCs reflect the properties of a cancer-causing agent, such as ‘is genotoxic,’ ‘is immunosuppressive’ or ‘modulates receptor-mediated effects,’ and are distinct from the hallmarks of cancer, which are the properties of tumors. To assess feasibility and limitations of applying the KCs to diverse agents, methods and results of mechanistic data evaluations were compiled from eight recent IARC Monograph meetings. A systematic search, screening and evaluation procedure identified a broad literature encompassing multiple KCs for most (12/16) IARC Group 1 or 2A carcinogens identified in these meetings. Five carcinogens are genotoxic and induce oxidative stress, of which pentachlorophenol, hydrazine and malathion also showed additional KCs. Four others, including welding fumes, are immunosuppressive. The overall evaluation was upgraded to Group 2A based on mechanistic data for only two agents, tetrabromobisphenol A and tetrachloroazobenzene. Both carcinogens modulate receptor-mediated effects in combination with other KCs. Fewer studies were identified for Group 2B or 3 agents, with the vast majority (17/18) showing only one or no KCs. Thus, an objective approach to identify and evaluate mechanistic studies pertinent to cancer revealed strong evidence for multiple KCs for most Group 1 or 2A carcinogens but also identified opportunities for improvement. Further development and mapping of toxicological and biomarker endpoints and pathways relevant to the KCs can advance the systematic search and evaluation of mechanistic data in carcinogen hazard identification. PMID:29562322

  1. Modelling of carcinogenic effects resulting from the combined action of radon and smoking

    Energy Technology Data Exchange (ETDEWEB)

    Ryabova, S.V.; Petin, V.G. [Medical Radiological Research Centre, Obninsk (Russian Federation)

    2002-03-01

    A simple mathematical model designed for the description of cell survival [1] and later developed for the evaluation of mutagenic effects [2] was proposed for the optimisation of the determination and prognosis of levels of carcinogenic effects in organisms, resulting from the combined action of different agents. The model postulates that the occurrence of synergism is to be expected as a result of additional carcinogenic damage arising from the interaction of sublesions induced by the two agents under investigation. These molecular sublesions are suggested to be non-carcinogenic, if each agent is taken separately. The main conclusion pertaining to this model is the existence of the highest level of synergistic effect. The model predicts the input values and conditions under which this level is reached. The synergistic effect appeared to decline with any deviation from the optimal value for the ratio of carcinogenic effects produced by each agent alone. These conclusions were verified by comparison with experimental data published by other researchers. (orig.)

  2. Protection by caffeine against oxic radiation damage and chemical carcinogens : mechanistic considerations

    International Nuclear Information System (INIS)

    Kesavan, P.C.

    1992-01-01

    There is little doubt that caffeine administered after exposure to UV light enhances the damage to cells and organisms by inhibiting photoreactivation, excision and/or recombinational repair. However, when already present in the system, it affords remarkable protection not only against O 2 -dependent component of radiation damage, but also against chemical carcinogens that require metabolic activation. Possible mechanistic aspects are discussed briefly. (author). 81 refs

  3. Development of HPLC and UV spectrophotometric methods for the determination of ascorbic acid using hydroxypropyl-β-cyclodextrin and triethanolamine as photostabilizing agents

    International Nuclear Information System (INIS)

    Garnero, Claudia; Longhi, Marcela

    2010-01-01

    In this study, the effect of complex formation with triethanolamine (TEA) alone and in combination with hydroxypropyl-β-cyclodextrin (HP-β-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.

  4. Metabolic activation of the bladder carcinogen 4-nitrobiphenyl (NBP)

    International Nuclear Information System (INIS)

    Swaminathan, S.

    1986-01-01

    The metabolism of NBP, a dog bladder carcinogen, was examined in vitro using rat liver tissues. NBP was metabolized by enzymes localized both in the microsomes and cytosol. The microsomal enzyme activity was inducible by Aroclor 1254 and phenobarbital. High pressure liquid chromatography analysis of the ethyl acetate extract of the reaction mixture, following incubation of [ 3 H]NBP with NADPH and microsomes, revealed four radioactive and UV absorbing peaks with retention times of 5, 8, 14 and 28 min. The peaks at 8, 14 and 28 min corresponded with 4-aminobiphenyl (ABP), NBP and azoxy biphenyl, respectively. The early eluting component with a retention time of 5 min has been tentatively identified as a ring hydroxylated derivative. In contrast to microsomal metabolism, cytosol-mediated metabolism yielded only one major metabolite identified as ABP. Cytosol-mediate reduction was inhibited by the xanthine oxidase inhibitor allopurinol. In vitro incubation of NBP with NADH and commercial preparations of xanthine oxidase also yielded ABP and the formation of the latter was blocked by allopurinol. Xanthine oxidase catalyzed also the binding of [ 3 H]NBP to DNA and proteins; the binding was inhibited by allopurinol. These data support the hypothesis that the nitro reduction step is involved in the activation of the bladder carcinogen NBP, and that the nitroreductases occur in both the microsomes and cytosol. The cytosolic activity is primarily due to xanthine oxidase

  5. IARC monographs: 40 years of evaluating carcinogenic hazards to humans.

    Science.gov (United States)

    Pearce, Neil; 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

    2015-06-01

    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. 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. 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. The IARC Monographs have made, and continue to make, major contributions to the scientific underpinning for societal actions to improve the public's health.

  6. Predictive Models for Carcinogenicity and Mutagenicity ...

    Science.gov (United States)

    Mutagenicity and carcinogenicity are endpoints of major environmental and regulatory concern. These endpoints are also important targets for development of alternative methods for screening and prediction due to the large number of chemicals of potential concern and the tremendous cost (in time, money, animals) of rodent carcinogenicity bioassays. Both mutagenicity and carcinogenicity involve complex, cellular processes that are only partially understood. Advances in technologies and generation of new data will permit a much deeper understanding. In silico methods for predicting mutagenicity and rodent carcinogenicity based on chemical structural features, along with current mutagenicity and carcinogenicity data sets, have performed well for local prediction (i.e., within specific chemical classes), but are less successful for global prediction (i.e., for a broad range of chemicals). The predictivity of in silico methods can be improved by improving the quality of the data base and endpoints used for modelling. In particular, in vitro assays for clastogenicity need to be improved to reduce false positives (relative to rodent carcinogenicity) and to detect compounds that do not interact directly with DNA or have epigenetic activities. New assays emerging to complement or replace some of the standard assays include VitotoxTM, GreenScreenGC, and RadarScreen. The needs of industry and regulators to assess thousands of compounds necessitate the development of high-t

  7. 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)

    Isoir, M.

    2006-06-01

    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)

  8. COMMUNITY-BASED UV RISK EDUCATION: THE SUNWISE PROGRAM HANDBOOK

    Science.gov (United States)

    This handbook is a user-friendly "How-to Guide" on providing information on how the SunWise project: 1) increased understanding of the importance of Ultraviolet light as a carcinogenic agent and an agent of skin aging, 2) disseminated time-relevant information on when (times of d...

  9. 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.

  10. Persistence of sister chromatid exchanges and in vitro morphological transformation of Syrian hamster fetal cells by chemical and physical carcinogens

    International Nuclear Information System (INIS)

    Popescu, N.C.; Amsbaugh, S.C.; DiPaolo, J.A.

    1985-01-01

    The induction of neoplastic cell transformation is closely associated with DNA alterations which occur shortly after carcinogen exposure. Sister chromatid exchange (SCE) formation is a sensitive indicator of carcinogen-DNA interaction and correlates with the induction of morphological cell transformation. The persistence of lesions generating SCE produced by chemical and physical carcinogens and its relevance to the induction of morphologic transformation was evaluated in coordinated experiments with cultured Syrian hamster fetal cells (HFC). Exponentially growing HFC were exposed for 1 h to benzo[a]pyrene (BP), methyl-methanesulfonate (MMS), cis-platinum (II) diaminedichloride (cis Pt II), N-methyl-N'-nitrosourea (MNU), mitomycin C (MMC), N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), N-acetoxy-2-fluorenyl-acetamide (AcAAF) or u.v. light irradiated. SCE analysis demonstrates that for a period of 48 h after carcinogen exposure, during which time the cells undergo at least four replicative cycles, DNA damage generating SCE induced by all chemical carcinogens either persisted or was partially removed, whereas u.v.-induced lesions were completely removed. An elevated SCE frequency persisted after two additional cell cycles after treatment with BP, AcAAF or MMC without increased cell lethality as compared to other carcinogens whose lesions were completely eliminated during the same period

  11. 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...... observation period. Side effects were evaluated clinically. No tumors appeared in untreated control mice or in just IPL-treated mice. Skin tumors developed in UV-exposed mice independently of IPL treatments. The time it took for 50% of the mice to first develop skin tumor ranged from 47 to 49 weeks...... in preoperative UV-exposed mice (p=0.94) and from 22 to 23 weeks in pre- and postoperative UV-exposed mice (p=0.11). IPL rejuvenation of lightly pigmented skin did not induce pigmentary changes (p=1.00). IPL rejuvenation of UV-pigmented skin resulted in an immediate increased skin pigmentation and a subsequent...

  12. Respiratory carcinogenicity assessment of soluble nickel compounds.

    Science.gov (United States)

    Oller, Adriana R

    2002-10-01

    The many chemical forms of nickel differ in physicochemical properties and biological effects. Health assessments for each main category of nickel species are needed. The carcinogenicity assessment of water-soluble nickel compounds has proven particularly difficult. Epidemiologic evidence indicates an association between inhalation exposures to nickel refinery dust containing soluble nickel compounds and increased risk of respiratory cancers. However, the nature of this association is unclear because of limitations of the exposure data, inconsistent results across cohorts, and the presence of mixed exposures to water-insoluble nickel compounds and other confounders that are known or suspected carcinogens. Moreover, well-conducted animal inhalation studies, where exposures were solely to soluble nickel, failed to demonstrate a carcinogenic potential. Similar negative results were seen in animal oral studies. A model exists that relates respiratory carcinogenic potential to the bioavailability of nickel ion at nuclear sites within respiratory target cells. This model helps reconcile human, animal, and mechanistic data for soluble nickel compounds. For inhalation exposures, the predicted lack of bioavailability of nickel ion at target sites suggests that water-soluble nickel compounds, by themselves, will not be complete human carcinogens. However, if inhaled at concentrations high enough to induce chronic lung inflammation, these compounds may enhance carcinogenic risks associated with inhalation exposure to other substances. Overall, the weight of evidence indicates that inhalation exposure to soluble nickel alone will not cause cancer; moreover, if exposures are kept below levels that cause chronic respiratory toxicity, any possible tumor-enhancing effects (particularly in smokers) would be avoided.

  13. The metabolic activation and nucleic acid adducts of naturally-occurring carcinogens: recent results with ethyl carbamate and the spice flavors safrole and estragole

    Energy Technology Data Exchange (ETDEWEB)

    Miller, J A; Miller, E C

    1983-07-01

    A small (approximately 30) but varied group of organic and inorganic compounds appear to be carcinogenic in both humans and experimental animals. A much larger number and wider variety of chemical carcinogens, primarily synthetic organic compounds, are known for experimental animals. These agents include a small (approximately 30) and varied group of metabolites of green plants and fungi. Many more of these carcinogens must exist in the living world. As with the synthetic carcinogens, the majority of these naturally occurring carcinogens are procarcinogens that require metabolic conversion into reactive electrophilic and mutagenic ultimate carcinogens. These strong electrophiles combine covalently and non-enzymatically with nucleophilic sites in DNAs, RNAs, proteins, and small molecules in target tissues. One or more of the DNA adducts appear to initiate carcinogenesis in an irreversible manner. The subsequent promotion step leading to gross tumours may be completed by further administration of carcinogen or by treatment with non-carcinogenic promoters. Roles for the RNA and protein adducts in the carcinogenic process have not been excluded. Recent data on the metabolic activation and reactivity in vivo of the naturally occurring carcinogens ethyl carbamate and certain of the alkenylbenzene spice flavours are illustrative of these principles. These agents can initiate the carcinogenic process in male mouse liver with small doses given prior to weaning. Subsequent growth of the liver and male hormonal factors appear to function as promoters leading to gross hepatic tumors after one year. Reactive electrophilic metabolites of ethyl carbamate and of safrole and estragole and their nucleic acid adducts formed during initiation in mouse liver have been characterized.

  14. Site-specific induction of nuclear anomalies (apoptotic bodies and micronuclei) by carcinogens in mice

    International Nuclear Information System (INIS)

    Ronen, A.; Heddle, J.A.

    1984-01-01

    The usefulness of nuclear anomalies (NA) as a short-term test for indication of carcinogens in the mouse colon has been suggested previously by experiments in which colon-specific carcinogens induced NA in the colon, whereas non-colon carcinogens were, in general, impotent in that organ. We have extended this work to other sites in the digestive tract of female C57BL/6 mice treated with gamma-rays, 1,2-dimethylhydrazine dihydrochloride, or N-methylnitrosourea. Each agent induced NA at all of the sites examined. The frequency of NA at different times after treatment depended upon both the agent used and the site examined. 1,2-Dimethylhydrazine dihydrochloride (which is known to induce tumors predominantly in the colon) induces NA with the highest efficiency (relative to gamma-rays) in the descending colon. N-Methylnitrosourea (which induces tumors mainly in the forestomach) induces NA with the highest efficiency in the forestomach. These results further support the usefulness of the assay in that the frequency of NA produced at the various sites by 1,2-dimethylhydrazine dihydrochloride and N-methylnitrosourea correlates with that found in the carcinogenicity studies

  15. Genotoxicity and potential carcinogenicity of cyanobacterial toxins - a review.

    Science.gov (United States)

    Zegura, Bojana; Straser, Alja; Filipič, Metka

    2011-01-01

    The occurrence of cyanobacterial blooms has increased significantly in many regions of the world in the last century due to water eutrophication. These blooms are hazardous to humans, animals, and plants due to the production of cyanotoxins, which can be classified in five different groups: hepatotoxins, neurotoxins, cytotoxins, dermatotoxins, and irritant toxins (lipopolysaccharides). There is evidence that certain cyanobacterial toxins are genotoxic and carcinogenic; however, the mechanisms of their potential carcinogenicity are not well understood. The most frequently occurring and widespread cyanotoxins in brackish and freshwater blooms are the cyclic heptapeptides, i.e., microcystins (MCs), and the pentapeptides, i.e., nodularins (NODs). The main mechanism associated with potential carcinogenic activity of MCs and NOD is the inhibition of protein phosphatases, which leads to the hyperphosphorylation of cellular proteins, which is considered to be associated with their tumor-promoting activity. Apart from this, MCs and NOD induce increased formation of reactive oxygen species and, consequently, oxidative DNA damage. There is also evidence that MCs and NOD induce micronuclei, and NOD was shown to have aneugenic activity. Both cyanotoxins interfere with DNA damage repair pathways, which, along with DNA damage, is an important factor involved in the carcinogenicity of these agents. Furthermore, these toxins increase the expression of TNF-α and early-response genes, including proto-oncogenes, genes involved in the response to DNA damage, cell cycle arrest, and apoptosis. Rodent studies indicate that MCs and NOD are tumor promotors, whereas NOD is thought to have also tumor-initiating activity. Another cyanobacterial toxin, cylindrospermopsin (CYN), which has been neglected for a long time, is lately being increasingly found in the freshwater environment. The principal mechanism of its toxicity is the irreversible inhibition of protein synthesis. It is pro

  16. Toxic Potential of Carcinogenic Polycyclic Aromatic Hydrocarbons ...

    African Journals Online (AJOL)

    Toxic Potential of Carcinogenic Polycyclic Aromatic Hydrocarbons (cPAHs) and Heavy Metal in Crude Oil from Gokana Area, Rivers State, Nigeria. ... Considerable caution should be applied in exploration, exposure and distribution of the crude oil through protected and well maintained pipelines to avoid the possible ...

  17. Mutagens and carcinogens in foods. Epidemiologic review.

    OpenAIRE

    Hislop, T. G.

    1993-01-01

    Evidence that diet contributes to the development of cancer is strengthening. This paper examines mutagens and carcinogens, such as naturally occurring substances, products of cooking and food processing, intentional and unintentional additives, and contaminants, found in foods. Such substances are present in minute quantities in the diets of average Canadians. Indication of health risk is largely limited to experimental laboratory evidence.

  18. Mutagens and carcinogens in foods. Epidemiologic review.

    Science.gov (United States)

    Hislop, T. G.

    1993-01-01

    Evidence that diet contributes to the development of cancer is strengthening. This paper examines mutagens and carcinogens, such as naturally occurring substances, products of cooking and food processing, intentional and unintentional additives, and contaminants, found in foods. Such substances are present in minute quantities in the diets of average Canadians. Indication of health risk is largely limited to experimental laboratory evidence. PMID:8499796

  19. Determination of carcinogenic polycyclic aromatic hydrocarbons in ...

    African Journals Online (AJOL)

    Determination of carcinogenic polycyclic aromatic hydrocarbons in air samples in Irbid, north Jordan. A Al-Gawadreh Sat, M.B. Gasim, A.R. Hassan, A Azid. Abstract. Air samples were collected at an urban site and a rural (BERQESH) site during February (2017) until March (2017) to determine concentrations of polycyclic ...

  20. Biomonitoring human exposure to environmental carcinogenic chemicals

    DEFF Research Database (Denmark)

    Farmer, P.B.; Sepai, O.; Lawrence, R.

    1996-01-01

    for detecting carcinogen-induced damage to DNA and proteins, and subsequent biological effects. These methods were validated with the occupational exposures, which showed evidence of DNA and/or protein and/or chromosome damage in workers in a coke oven plant, garage workers exposed to diesel exhaust and workers...

  1. Immunologic methods for monitoring carcinogen exposure

    Science.gov (United States)

    Santella, Regina M.; Perera, Frederica P.; Zhang, Yu J.; Chen, Chen J.; Young, Tie L.

    1993-03-01

    Immunologic methods have been developed for monitoring human exposure to environmental and occupational carcinogens. These methods involve the development of monoclonal and polyclonal antisera which specifically recognize the carcinogens themselves or their DNA or protein adducts. Antisera recognizing the DNA adducts of several polycyclic aromatic hydrocarbon diol epoxides have been used in competitive enzyme-linked immunosorbent assays to monitor adducts in tissue or blood samples. Elevated levels of DNA adducts have been seen in mononuclear cells of smokers and in total white blood cells of foundry and coke oven workers. Environmental exposure to PAH has been measured in individuals living in a highly polluted region of Poland. Antisera recognizing PAH-DNA adducts have also been used in immunohistochemical studies to monitor adducts in specific cells of biopsy samples. The DNA adducts of aflatoxin B1 have been monitored in liver tissue of hepatocellular carcinoma patients in Taiwan. Detectable adducts were seen in 50 - 70% of the patients suggesting that dietary exposure to this carcinogen may be a risk factor for cancer induction. Thus, immunoassays for monitoring exposure to carcinogens are an important tool in epidemiologic studies.

  2. 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.

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

    International Nuclear Information System (INIS)

    Melis, Joost P.M.; Speksnijder, Ewoud N.; Kuiper, Raoul V.; Salvatori, Daniela C.F.; Schaap, Mirjam M.; Maas, Saskia; Robinson, Joke; Verhoef, Aart; Benthem, Jan van; Luijten, Mirjam; Steeg, Harry van

    2013-01-01

    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.

  4. DNA-adducts in fish exposed to alkylating carcinogens

    International Nuclear Information System (INIS)

    Giam, C.S.; Holliday, T.L.; Williams, J.L.; Bahnson, A.; Weller, R.; Hinton, D.E.

    1988-01-01

    There are limited studies on DNA-adduct formation following exposure of fish or fish cells to carcinogens. It will be essential to determine if procarcinogens and carcinogens form the same DNA-adducts in different liver cells and how these compare to those reported in mammalian livers. They are also interested in the influence of different alkylating agents on the type and quantity of DNA-adduct formation and repair in fish. While eggs or small fish are ideal for routine screening, large fish such as trout (Salmo gairdneri) is needed initially for the development of analytical procedures for the isolation, quantitation and identification of various adducts. Trout (Salmo gairdneri) weighing approximately 250 grams were acclimatized at 13 degree C before being given i.p. injection of diethylnitrosoamine (DEN). The exposure period varied, though most animals were sacrificed after 24 hours. Their livers were excised and DNA was isolated mainly according the procedure of Croy et al. The neutral thermal hydrolysate and the acid hydrolysate were analyzed by HPLC-Fluorescent detector for 7-ethylguanine and O 6 -ethylguanine, respectively. O 6 -ethylguanine was detected, 7-ethylguanine was not detected. Attempts are being made to improve the detection of the latter compound. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) was used to establish nanogram quantities of the ethylated bases. Laser desorption FT-IC-MS is particularly useful for characterizing thermally-labile and involatile nucleosides or nucleotides. Excretion of DEN was rapid and high. Exposure of trout (and other fish) to various ethylating agents will be discussed

  5. EPA's evaluation of the carcinogenic potential of glyphosate

    Science.gov (United States)

    Recently, several international agencies have evaluated the carcinogenic potential of glyphosate. In March 2015, the International Agency for Research on Cancer (IARC), a subdivision of the World Health Organization (WHO), determined that glyphosate was a probable carcinogen (gro...

  6. [Risk assessment of carcinogenic and non-carcinogenic effects in the use of food].

    Science.gov (United States)

    Frolova, O A; Karpova, M V

    2012-01-01

    Application of methodology for assessing the risk of diseases associated with consumption of contaminated foods, is aimed at predicting possible changes in the future and helps to create a framework for the prevention of negative effects on public health. The purpose of the study is assessment of health risks formed under the influence of chemical contaminants that pollute the food. Exponential average daily dose of receipt of chemicals in the body, non-carcinogenic and carcinogenic risks were calculated.

  7. Detection of carcinogen-DNA adducts by radioimmunoassay

    International Nuclear Information System (INIS)

    Poirier, M.C.; Yuspa, S.H.; Weinstein, I.B.; Blobstein, S.

    1977-01-01

    Covalent binding of carcinogen to nucleic acids is believed to be an essential component of the carcinogenic process, so it is desirable to have highly sensitive and specific methods for detecting such adducts in cells and tissues exposed to known and suspected carcinogens. A radioimmunoassay is here described capable of detecting nanogram amounts of DNA adducts resulting from the covalent binding of the carcinogen N-2-acetylaminofluorene and its activated N-acetoxy derivative. (author)

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

    International Nuclear Information System (INIS)

    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

  9. Developments in assessing carcinogenic risks from radiation

    International Nuclear Information System (INIS)

    Beebe, G.W.

    1984-01-01

    The papers in this volume have ranged widely over theoretical, experimental, and epidemiologic topics relating to radiation carcinogenesis. The multistage character of carcinogenesis, emphasis on the ease with which the initial event occurs in contrast to the infrequency of carcinogenic expression, the role of cell repair, and factors that may influence expression were major themes of the theoretical and experimental papers. The elegance of the cell transformation tool was illustrated in reviews of experimental work dealing with the exposure and environmental variables that influence radiation-induced transformation, among them the intracellular environment. Arguments were advanced for the view that more than one cell must be affected by radiation if a critical event is to occur. The relative congruence of carcinogens and clastogens was noted, and the suggestion made that the rules governing the induction of chromosomal aberrations by ionizing may apply to radiation carcinogenesis as well

  10. Report on carcinogens monograph on 1-bromopropane.

    Science.gov (United States)

    2013-09-01

    The National Toxicology Program conducted a cancer evaluation on 1 bromopropane for possible listing in the Report on Carcinogens (RoC). The cancer evaluation is captured in the RoC monograph, which was peer reviewed in a public forum. The monograph consists of two components: (Part 1) the cancer evaluation, which reviews the relevant scientific information, assesses its quality, applies the RoC listing criteria to the scientific information, and provides the NTP recommendation for listing status for 1 bromopropane in the RoC, and (Part 2) the substance profile proposed for the RoC, containing the NTP's listing status recommendation, a summary of the scientific evidence considered key to reaching that decision, and data on properties, use, production, exposure, and Federal regulations and guidelines to reduce exposure to 1-bromopropane. This monograph provides an assessment of the available scientific information on 1 bromopropane, including human exposure and properties, disposition and toxicokinetics, cancer studies in experimental animals, and studies of mechanisms and other related effects, including relevant toxicological effects, genetic toxicology, and mechanisms of carcinogenicity. From this assessment, the NTP recommended that 1 bromopropane be listed as reasonably anticipated to be a human carcinogen in the RoC based on sufficient evidence from studies in experimental animals, which found inhalation exposure to 1-bromopropane caused skin tumors in male rats, large intestine tumors in female and male rats, and lung tumors in female mice. Also noted was that 1 bromopropane, either directly or via reactive metabolites, caused molecular alterations that typically are associated with carcinogenesis, including genotoxicity, oxidative stress, and glutathione depletion. These alterations, observed in mainly in vitro and toxicity studies in rodents, are relevant to possible mechanisms of human carcinogenicity and support the relevance of the cancer studies in

  11. 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.

  12. Respiratory carcinogenicity assessment of soluble nickel compounds.

    OpenAIRE

    Oller, Adriana R

    2002-01-01

    The many chemical forms of nickel differ in physicochemical properties and biological effects. Health assessments for each main category of nickel species are needed. The carcinogenicity assessment of water-soluble nickel compounds has proven particularly difficult. Epidemiologic evidence indicates an association between inhalation exposures to nickel refinery dust containing soluble nickel compounds and increased risk of respiratory cancers. However, the nature of this association is unclear...

  13. Recent developments in carcinogenic risk assessment

    International Nuclear Information System (INIS)

    Krewski, D.; Murdoch, D.; Withey, J.R.

    1989-01-01

    In this paper, recent developments in the quantitative assessment of carcinogenic risks based on toxicological and epidemiological data are reviewed. In particular, model-free approaches to low-dose risk assessment which involve only the assumption of low-dose linearity are considered. Measures of carcinogenic potency which avoid the need to extrapolate to low doses are also described. The allometric bases for converting risk estimates between species are then discussed. Pharmacokinetic models for determining the dose delivered to the target tissue are examined, and the implications of using such models in extrapolating between doses, of exposure, and species are examined. The application of these concepts in chemical and radiation carcinogenesis is illustrated by means of brief case studies of methylene chloride and Rn. Biologically motivated cancer models based on the initiation-promotion-progression theory of carcinogenesis are discussed and compared with the classical multistage model. The estimation of risks with time-dependent exposure patterns is considered, and conditions under which the use of a time-weighted average dose is appropriate are identified. Finally, the estimation of carcinogenic risks posed by exposure to complex mixtures is explored. 92 references

  14. 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

  15. Molecular biomarkers of oxidative stress associated with bromate carcinogenicity

    International Nuclear Information System (INIS)

    Delker, Don; Hatch, Gary; Allen, James; Crissman, Bobby; George, Michael; Geter, David; Kilburn, Steve; Moore, Tanya; Nelson, Gail; Roop, Barbara; Slade, Ralph; Swank, Adam; Ward, William; DeAngelo, Anthony

    2006-01-01

    Potassium bromate (KBrO 3 ) is a chemical oxidizing agent found in drinking water as a disinfection byproduct of surface water ozonation. Chronic exposures to KBrO 3 cause renal cell tumors in rats, hamsters and mice and thyroid and testicular mesothelial tumors in rats. Experimental evidence indicates that bromate mediates toxicological effects via the induction of oxidative stress. To investigate the contribution of oxidative stress in KBrO 3 -induced cancer, male F344 rats were administered KBrO 3 in their drinking water at multiple concentrations for 2-100 weeks. Gene expression analyses were performed on kidney, thyroid and mesothelial cell RNA. Families of mRNA transcripts differentially expressed with respect to bromate treatment included multiple cancer, cell death, ion transport and oxidative stress genes. Multiple glutathione metabolism genes were up-regulated in kidney following carcinogenic (400 mg/L) but not non-carcinogenic (20 mg/L) bromate exposures. 8-Oxodeoxyguanosine glycosylase (Ogg1) mRNA was up-regulated in response to bromate treatment in kidney but not thyroid. A dramatic decrease in global gene expression changes was observed following 1 mg/L compared to 20 mg/L bromate exposures. In a separate study oxygen-18 ( 18 O) labeled KBrO 3 was administered to male rats by oral gavage and tissues were analyzed for 18 O deposition. Tissue enrichment of 18 O was observed at 5 and 24 h post-KBr 18 O 3 exposure with the highest enrichment occurring in the liver followed by the kidney, thyroid and testes. The kidney dose response observed was biphasic showing similar statistical increases in 18 O deposition between 0.25 and 50 mg/L (equivalent dose) KBr 18 O 3 followed by a much greater increase above 50 mg/L. These results suggest that carcinogenic doses of potassium bromate require attainment of a threshold at which oxidation of tissues occurs and that gene expression profiles may be predictive of these physiological changes in renal homeostasis

  16. Inhibiting the regeneration of N-nitrosodimethylamine in drinking water by UV photolysis combined with ozonation

    International Nuclear Information System (INIS)

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

    2009-01-01

    N-Nitrosodimethylamine (NDMA) is a highly carcinogenic compound that is suspected of carcinogenic activity in the human body. A variety of methods are used to remove NDMA from water, but the main degradation products, dimethylamine (DMA) and NO 2 - , are also precursors for NDMA formation. UV irradiation combined with ozonation (UV/O 3 ) was examined in this investigation for its ability to inhibit the regeneration of NDMA after degradation. Both the degradation products and the regeneration potential of NDMA were compared between UV irradiation alone and UV/O 3 . The yields of DMA and NO 2 - in the UV/O 3 process were less than for UV irradiation alone. Yields of DMA and NO 2 - were 2.25 mg L -1 and 3.22 mg L -1 from UV irradiation, while they were 0.92 mg L -1 and 0.45 mg L -1 from the UV/O 3 process. Furthermore, the regeneration of NDMA was also less after the UV/O 3 process than after UV irradiation. The concentration of regenerated NDMA was more than 51.8 μg L -1 after UV irradiation regardless of the dosage of Cl 2 . However, the concentration of regenerated NDMA in the UV/O 3 process was less than 7.37 μg L -1 under the same conditions. Consequently, the UV/O 3 process was more effective than UV irradiation alone in inhibiting NDMA regeneration. The inhibition of NDMA regeneration was due to a decrease in DMA and NO 2 - produced by the UV/O 3 process. As the major products generated from NDMA, NO 2 - and DMA were likely to be oxidized by ozone and hydroxyl radicals (·OH). In addition, the reaction between NDMA and ·OH would possibly generate methylamine as the only product, leading to a decrease in the production of DMA by the UV/O 3 process.

  17. The protective effect of some Thai plants and their bioactive compounds in UV light-induced skin carcinogenesis.

    Science.gov (United States)

    de Silva, Madhura B; Tencomnao, Tewin

    2018-05-02

    Skin cancer, represents a major public health concern. While the vast majority is non-melanoma skin cancers, melanomas are mostly responsible for mortality. Solar UVB radiation is mutagenic and carcinogenic. It is primarily responsible for both non-melanoma and melanoma skin cancers via excessive production of reactive oxygen species (ROS), which mediate changes in inflammation and immunity, and have been implicated in all three stages of skin cancer development. Due to their regulatory role in numerous functions of cells, signaling pathways are targets for chemoprevention. The current standards in melanoma therapy are targeted and combination therapies, which, albeit prolong survival responses, are still prone to development of drug resistance. To this extent, drugs of natural origin continue to spark great interest. Thailand has a rich biodiversity of indigenous flora, which have traditionally been used to treat a variety of pathologies. The active components in plant extracts that have medicinal properties, termed 'bioactive compounds,' are efficient chemopreventive agents due to their antioxidant, antimutagenic, anticarcinogenic, and carcinogen detoxification properties. Thai plants and their bioactive compounds have shown protective effects on UV light-induced skin cancer in different experimental models. This warrants further in vivo investigations and translation to clinical studies to determine efficacy and safety, for use as lead compounds in targeted/combination therapy or adjuvant therapy with existing regimes. Coupled with a strategy for prevention, this offers a promising outlook for protection against photocarcinogenesis. Copyright © 2018 Elsevier B.V. All rights reserved.

  18. Mechanisms underlying UV-induced immune suppression

    International Nuclear Information System (INIS)

    Ullrich, Stephen E.

    2005-01-01

    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

  19. Report on carcinogens monograph on cumene.

    Science.gov (United States)

    2013-09-01

    The National Toxicology Program conducted a cancer evaluation on cumene for possible listing in the Report on Carcinogens (RoC). The cancer evaluation is captured in the RoC monograph, which was peer reviewed in a public forum. The monograph consists of two components: (Part 1) the cancer evaluation, which reviews the relevant scientific information, assesses its quality, applies the RoC listing criteria to the scientific information, and provides the NTP recommendation for listing status for cumene in the RoC, and (Part 2) the substance profile proposed for the RoC, containing the NTP's listing status recommendation, a summary of the scientific evidence considered key to reaching that decision, and data on properties, use, production, exposure, and Federal regulations and guidelines to reduce exposure to cumene. This monograph provides an assessment of the available scientific information on cumene, including human exposure and properties, disposition and toxicokinetics, cancer studies in experimental animals, and studies of mechanisms and other related effects, including relevant toxicological effects, genetic toxicology, and mechanisms of carcinogenicity. From this assessment, the NTP recommended that cumene be listed as reasonably anticipated to be a human carcinogen in the RoC based on sufficient evidence from studies in experimental animals, which found that cumene exposure caused lung tumors in male and female mice and liver tumors in female mice. Several proposed mechanisms of carcinogenesis support the relevance to humans of the lung and liver tumors observed in experimental animals. Specifically, there is evidence that humans and experimental animals metabolize cumene through similar metabolic pathways. In addition, mutations of the K-ras oncogene and p53 tumor-suppressor gene observed in cumene-induced lung tumors in mice, along with altered expression of many other genes, resemble molecular alterations found in human lung and other cancers.

  20. Mequindox Induced Genotoxicity and Carcinogenicity in Mice

    Directory of Open Access Journals (Sweden)

    Qianying Liu

    2018-04-01

    Full Text Available Mequindox (MEQ, acting as an inhibitor of deoxyribonucleic acid (DNA synthesis, is a synthetic heterocyclic N-oxides. To investigate the potential carcinogenicity of MEQ, four groups of Kun-Ming (KM mice (50 mice/sex/group were fed with diets containing MEQ (0, 25, 55, and 110 mg/kg for one and a half years. The result showed adverse effects on body weights, feed consumption, hematology, serum chemistry, organ weights, relative organ weights, and incidence of tumors during most of the study period. Treatment-related changes in hematology, serum chemistry, relative weights and histopathological examinations revealed that the hematological system, liver, kidneys, and adrenal glands, as well as the developmental and reproductive system, were the main targets after MEQ administration. Additionally, MEQ significantly increased the frequency of micronucleated normochromatic erythrocytes in bone marrow cells of mice. Furthermore, MEQ increased the incidence of tumors, including mammary fibroadenoma, breast cancer, corticosuprarenaloma, haemangiomas, hepatocarcinoma, and pulmonary adenoma. Interestingly, the higher incidence of tumors was noted in M25 mg/kg group, the lowest dietary concentration tested, which was equivalent to approximately 2.25 and 1.72 mg/kg b.w./day in females and males, respectively. It was assumed that the lower toxicity might be a reason for its higher tumor incidence in M25 mg/kg group. This finding suggests a potential relationships among the dose, general toxicity and carcinogenicity in vivo, and further study is required to reveal this relationship. In conclusion, the present study demonstrates that MEQ is a genotoxic carcinogen in KM mice.

  1. Glyphosate rodent carcinogenicity bioassay expert panel review.

    Science.gov (United States)

    Williams, Gary M; Berry, Colin; Burns, Michele; de Camargo, Joao Lauro Viana; Greim, Helmut

    2016-09-01

    Glyphosate has been rigorously and extensively tested for carcinogenicity by administration to mice (five studies) and to rats (nine studies). Most authorities have concluded that the evidence does not indicate a cancer risk to humans. The International Agency for Research on Cancer (IARC), however, evaluated some of the available data and concluded that glyphosate probably is carcinogenic to humans. The expert panel convened by Intertek assessed the findings used by IARC, as well as the full body of evidence and found the following: (1) the renal neoplastic effects in males of one mouse study are not associated with glyphosate exposure, because they lack statistical significance, strength, consistency, specificity, lack a dose-response pattern, plausibility, and coherence; (2) the strength of association of liver hemangiosarcomas in a different mouse study is absent, lacking consistency, and a dose-response effect and having in high dose males only a significant incidence increase which is within the historical control range; (3) pancreatic islet-cell adenomas (non-significant incidence increase), in two studies of male SD rats did not progress to carcinomas and lacked a dose-response pattern (the highest incidence is in the low dose followed by the high dose); (4) in one of two studies, a non-significant positive trend in the incidence of hepatocellular adenomas in male rats did not lead to progression to carcinomas; (5) in one of two studies, the non-significant positive trend in the incidence of thyroid C-cell adenomas in female rats was not present and there was no progression of adenomas to carcinomas at the end of the study. Application of criteria for causality considerations to the above mentioned tumor types and given the overall weight-of-evidence (WoE), the expert panel concluded that glyphosate is not a carcinogen in laboratory animals.

  2. Carcinogen-induced damage to DNA

    International Nuclear Information System (INIS)

    Strauss, B.; Altamirano, M.; Bose, K.; Sklar, R.; Tatsumi, K.

    1979-01-01

    Human cells respond to carcinogen-induced damage in their DNA in at least two ways. The first response, excision repair, proceeds by at least three variations, depending on the nature of the damage. Nucleotide excision results in relatively large repair patches but few free DNA breaks, since the endonuclease step is limiting. Apurinic repair is characterized by the appearance of numerous breaks in the DNA and by short repair patches. The pathways behave as though they function independently. Lymphoic cells derived from a xeroderma pigmentosum complementation group C patient are deficient in their ability to perform nucleotide excision and also to excise 6 methoxyguanine adducts, but they are apurinic repair competent. Organisms may bypass damage in their DNA. Lymphoblastoid cells, including those derived from xeroderma pigmentosum treated with 3 H-anti-BPDE, can replicate their DNA at low doses of carcinogen. Unexcised 3 H is found in the light or parental strand of the resulting hybrid DNA when replication occurs in medium with BrdUrd. This observation indicates a bypass reaction occurring by a mechanism involving branch migration at DNA growing points. Branch migration in DNA preparations have been observed, but the evidence is that most occurs in BrdUrd-containing DNA during cell lysis. The measurement of the bifilarly substituted DNA resulting from branch migration is a convenient method of estimating the proportion of new synthesis remaining in the vicinity of the DNA growing point. Treatment with carcinogens or caffeine results in accumulation of DNA growing points accompanied by the synthesis of shortened pieces of daughter DNA

  3. Electrochemical methods for monitoring of environmental carcinogens.

    Science.gov (United States)

    Barek, J; Cvacka, J; Muck, A; Quaiserová, V; Zima, J

    2001-04-01

    The use of modern electroanalytical techniques, namely differential pulse polarography, differential pulse voltammetry on hanging mercury drop electrode or carbon paste electrode, adsorptive stripping voltammetry and high performance liquid chromatography with electrochemical detection for the determination of trace amounts of carcinogenic N-nitroso compounds, azo compounds, heterocyclic compounds, nitrated polycyclic aromatic hydrocarbons and aromatic and heterocyclic amines is discussed. Scope and limitations of these methods are described and some practical applications based on their combination with liquid-liquid or solid phase extraction are given.

  4. Effects of garlic on cellular doubling time and DNA strand breaks caused by UV light and BPL, enhanced with catechol and TPA

    International Nuclear Information System (INIS)

    Baturay, N.Z.; Gayle, F.; Liu, S.; Kreidinger, C.

    1995-01-01

    3T3 cell cultures were exposed to UV light and Beta-Propiolactone. Neoplastic cell transformation (TF) was demonstrated after concurrent addition of catechol, or repeated addition of TPA. Addition of garlic to all fluences/concentrations of the carcinogen/cocarcinogen/promoter groups reduced the number of transformed foci/dish by at least 40%. Since the cell cycle is prolonged following exposure to carcinogens, it is likely the cell requires a longer time to repair this damage. The doubling time (DT) was extended from 12 to 36 hrs. when cells were exposed to BPL and from 12 o 28 hrs. when cells were exposed to 3.0J/M2/sec. If an anticarcinogenic compound is also added, it is reasonable to assume that the cell cycle may be further elongated. The cell cycle, denoted by DT was lengthened from 12 to 47 hrs and from 12 to 86 hrs for BPL and UVC, respectively. The extensions occurred in a dope dependent manner. The concentrations of the cocarcinogen and promoter remained constant throughout the experiment. When strand breaks were determined at the same dose sequences, by alkaline elution, more repair was seen with garlic where the lowest and middle doses of BPL were used and almost no decrease in % DNA eluted was seen with UVC exposed cells. With catechol, there was a two-fold decrease in % DNA eluted at the lowest and middle fluences. When TPA was added, all three fluences of UVC showed more than a threefold decrease in % DNA eluted. BPS with both TPA and catechol, again showed a reduction in strand breaks only low and middle doses. Both a direct-acting alkylating agent, BPL, and a physical carcinogen, UVC, were homogeneously affected, in terms of doubling time, but not when strand break repair was examined. A separate mechanism may be responsible for repair, and the mechanism associated with combinations of physical carcinogen enhancing agents combined with some non-carcinogens may be more profoundly affected by some natural products

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

    International Nuclear Information System (INIS)

    Gold, K.W.; Naugle, D.F.; Berry, M.A.

    1991-01-01

    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

  6. 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.

  7. The potential carcinogenic risk of tanning beds: clinical guidelines and patient safety advice

    Directory of Open Access Journals (Sweden)

    Mette Mogensen

    2010-10-01

    Full Text Available Mette Mogensen1, Gregor BE Jemec21Department of Dermatology, Gentofte Hospital, Hellerup, Denmark; 2Department of Dermatology, Roskilde Hospital, Health Sciences Faculty, University of Copenhagen, Roskilde, DenmarkIntroduction: In 2009, the WHO listed ultraviolet (UV radiation as a group 1 carcinogen. In spite of this, each year, millions of people tan indoor in Western countries. The aim of this review is to summarize evidence of tanning bed carcinogenesis and to present guidelines for use of tanning beds and patient safety advice.Methods: A narrative review of the literature was conducted based on both PubMed and Medline searches and on literature review of the retrieved papers.Results: Use of indoor tanning beds represents a significant and avoidable risk factor for the development of both melanoma and nonmelanoma skin cancers. Frequent tanners are more often adolescent females. Tanning beds have additional potential adverse effects such as burns, solar skin damage, infection, and possibly also addictive behavior.Discussion: The effort in preventing UV light-induced carcinogenesis should currently be aimed at developing new strategies for public health information. Tanning beds are one preventable source of UV radiation. In the majority of people solar UV radiation continues to be the major factor and therefore anti-tanning campaigns must always include sunbathers.Keywords: tanning beds, skin cancers, melanoma, nonmelanoma

  8. The potential carcinogenic risk of tanning beds: clinical guidelines and patient safety advice

    International Nuclear Information System (INIS)

    Mogensen, Mette; Jemec, Gregor BE

    2010-01-01

    In 2009, the WHO listed ultraviolet (UV) radiation as a group 1 carcinogen. In spite of this, each year, millions of people tan indoor in Western countries. The aim of this review is to summarize evidence of tanning bed carcinogenesis and to present guidelines for use of tanning beds and patient safety advice. A narrative review of the literature was conducted based on both PubMed and Medline searches and on literature review of the retrieved papers. Use of indoor tanning beds represents a significant and avoidable risk factor for the development of both melanoma and nonmelanoma skin cancers. Frequent tanners are more often adolescent females. Tanning beds have additional potential adverse effects such as burns, solar skin damage, infection, and possibly also addictive behavior. The effort in preventing UV light-induced carcinogenesis should currently be aimed at developing new strategies for public health information. Tanning beds are one preventable source of UV radiation. In the majority of people solar UV radiation continues to be the major factor and therefore anti-tanning campaigns must always include sunbathers

  9. Comparison of the carcinogenic effectiveness in mouse skin of methyl- and ethylnitrosourea, nitrosourethane and nitrosonitro-guanidine and the effect of deuterium labeling

    International Nuclear Information System (INIS)

    Lijinsky, W.

    1982-01-01

    The carcinogenic activities of a number of directly acting methylating and ethylating agents have been compared by mouse skin painting in acetone solution. Nitrosomethylurethane and nitrosoethylurethane failed to induce tumors after greater than 60 weeks treatment. Nitrosomethylurea was somewhat more effective than nitrosoethylurea, as measured by the longer latent period than nitrosoethylurea, as measured Nitrosomethylnitroguanidine, by the same measure, was a weaker carcinogen than nitrosoethylnitroguanidine at both dose levels used (0.02 M and 0.008 M); the latter compound was the most potent skin carcinogen of those examined. There was no significant difference in carcinogenic effectiveness when the alkyl group of the nitrosoureas or the nitronitrosoguanidines contained deuterium instead of hydrogen, which supports the concept that alkylation of cellular macromolecules by the intact alkyl group is responsible for carcinogenesis by these compounds

  10. Synthetic risks, risk potency, and carcinogen regulation.

    Science.gov (United States)

    Viscusi, W K; Hakes, J K

    1998-01-01

    This article analyzes a comprehensive sample of over 350 chemicals tested for carcinogenicity to assess the determinants of the probability of regulation. Controlling for differences in the risk potency and noncancer risks, synthetic chemicals have a significantly higher probability of regulation overall: this is due to the greater likelihood of U.S. Food and Drug Administration (FDA) regulation. Measures of risk potency increase the probability of regulation by the U.S. Environmental Protection Agency (EPA), have a somewhat weaker positive effect on regulation by the U.S. Occupational Safety and Health Administration (OSHA), and decrease the likelihood of regulation by the FDA. The overall regulatory pattern is one in which the FDA targets synthetic chemicals and chemicals that pose relatively minor cancer risk. The EPA particularly performed more sensibly than many critics have suggested.

  11. Effects of Radon and UV Exposure on Skin Cancer Mortality in Switzerland

    NARCIS (Netherlands)

    Vienneau, Danielle; de Hoogh, Kees; Hauri, Dimitri D.; Vicedo-Cabrera, Ana M; Schindler, Christian; Huss, Anke; Röösli, Martin

    2017-01-01

    BACKGROUND: Skin cancer incidence in Switzerland is among the highest in the world. In addition to exposure to ultraviolet (UV) radiation, radon alpha particles attached to aerosols can adhere to the skin and potentially cause carcinogenic effects. OBJECTIVES: We investigated the effects of radon

  12. Nitrosamine degradation by UV light in post-combustion CO2 capture: effect of solvent matrix

    NARCIS (Netherlands)

    Miguel Mercader, F. de; Voice, A.K.; Trap, H.C.; Goetheer, E.L.V.

    2013-01-01

    Potential production and emission of nitrosamines during post-combustion CO2 capture has drawn some attention due to their toxicity and potential carcinogenicity. One of the possible ways to reduce the concentration of nitrosamines is irradiation of the liquid streams of the capture plant with UV

  13. Genotoxicity of Swimming Pool Water and Carcinogenicity of Drinking Water

    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 (chloroaceticacid and chlorite) are not carcinogenic-in either of2 species; (b) chlorite is not carcinogenic in 3 rodent assays and has never been tested for genotoxicity...

  14. Genotoxicity of Swimming Pool Water and Carcinogenicity of Drinking Water**

    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 (chloroaceticacid and chlorite) are not carcinogenic-in either of2 species; (b) chlorite is not carcinogenic in 3 rodent assays and has never been tested for genotoxicity...

  15. QSAR ligand dataset for modelling mutagenicity, genotoxicity, and rodent carcinogenicity

    Directory of Open Access Journals (Sweden)

    Davy Guan

    2018-04-01

    Full Text Available Five datasets were constructed from ligand and bioassay result data from the literature. These datasets include bioassay results from the Ames mutagenicity assay, Greenscreen GADD-45a-GFP assay, Syrian Hamster Embryo (SHE assay, and 2 year rat carcinogenicity assay results. These datasets provide information about chemical mutagenicity, genotoxicity and carcinogenicity.

  16. 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)

  17. North American Magazine Coverage of Skin Cancer and Recreational Tanning Before and After the WHO/IARC 2009 Classification of Indoor Tanning Devices as Carcinogenic.

    Science.gov (United States)

    McWhirter, Jennifer E; Hoffman-Goetz, Laurie

    2015-09-01

    The mass media is an influential source of skin cancer information for the public. In 2009, the World Health Organization's International Agency for Research on Cancer classified UV radiation from tanning devices as carcinogenic. Our objective was to determine if media coverage of skin cancer and recreational tanning increased in volume or changed in nature after this classification. We conducted a directed content analysis on 29 North American popular magazines (2007-2012) to investigate the overall volume of articles on skin cancer and recreational tanning and, more specifically, the presence of skin cancer risk factors, UV behaviors, and early detection information in article text (n = 410) and images (n = 714). The volume of coverage on skin cancer and recreational tanning did not increase significantly after the 2009 classification of tanning beds as carcinogenic. Key-related messages, including that UV exposure is a risk factor for skin cancer and that indoor tanning should be avoided, were not reported more frequently after the classification, but the promotion of the tanned look as attractive was conveyed more often in images afterwards (p skin cancer risk factors, other UV behaviors, or early detection information over time. The classification of indoor tanning beds as carcinogenic had no significant impact on the volume or nature of skin cancer and recreational tanning coverage in magazines.

  18. Índice UV

    Science.gov (United States)

    Información general sobre el Índice UV que proporciona un pronóstico del riesgo esperado de sobreexposición a la radiación ultravioleta (UV) del sol. El índice UV va acompañado de recomendaciones para protegerse del sol.

  19. uv dye lasers

    International Nuclear Information System (INIS)

    Abakumov, G.A.; Fadeev, V.V.; Khokhlov, R.V.; Simonov, A.P.

    1975-01-01

    The most important property of visible dye lasers, that is, continuous wavelength tuning, stimulated the search for dyes capable to lase in uv. They were found in 1968. Now the need for tunable uv lasers for applications in spectroscopy, photochemistry, isotope separation, remote air and sea probing, etc. is clearly seen. A review of some recent advances in uv dye lasers is reviewed

  20. Mémoire du travail et des expositions professionnelles aux cancérogènes Work account and occupational exposures to carcinogens. Survey in Seine-Saint-Denis (France Memoria del trabajo y de las exposiciones profesionales a agentes cancerígenos. Encuesta en Seine-Saint-Denis (Francia

    Directory of Open Access Journals (Sweden)

    Annie Thébaud-Mony

    2010-11-01

    Full Text Available Selon les estimations officielles, en 2000 environ 32 millions de travailleurs européens (de l’Europe des 15 étaient exposés à des cancérogènes. Depuis 2002, considérant la maladie comme « événement-sentinelle » pour la connaissance des activités de travail exposant aux cancérogènes, le Groupement d’intérêt scientifique sur les cancers d’origine professionnelle (GISCOP93 mène une enquête permanente auprès de patients atteints de cancer en Seine Saint Denis (France. S’appuyant sur les récits recueillis auprès des patients et sur l’expertise des spécialistes en matière d’exposition, une démarche d’analyse et de classement des activités exposées a été réalisée pour l’élaboration d’un répertoire des activités de travail en présence de produits/procédés cancérogènes. L’objectif de cet article est de mettre en perspective cette nouvelle base de données par rapport à quelques sources d’information concernant l’exposition professionnelle aux cancérogènes, déjà disponibles en ligne, en montrant l’apport d’une méthode de recueil d’information fondée sur l’expérience et la parole des travailleurs.According to official estimates, in the year 2000, approximately 32 million European workers (in Europe 15 were exposed to carcinogens. Since 2002, considering the disease as a "sentinel-event" for understanding the work activities that expose workers to carcinogens, the GISCOP93 research group has been carrying out an ongoing survey on patients with cancer in Seine-Saint-Denis (France. Based on the patients’ narratives and on the expertise of exposure hazard specialists, an analysis and classification of the exposed working activities was carried out to build a new database of work activities in the presence of carcinogenic products/processes. The aim of this article is to present this database in relation to some other sources of information on occupational exposure to carcinogens

  1. Polycyclic aromatic hydrocarbons (PAHs) skin permeation rates change with simultaneous exposures to solar ultraviolet radiation (UV-S).

    Science.gov (United States)

    Hopf, Nancy B; Spring, Philipp; Hirt-Burri, Nathalie; Jimenez, Silvia; Sutter, Benjamin; Vernez, David; Berthet, Aurelie

    2018-05-01

    Road construction workers are simultaneously exposed to two carcinogens; solar ultraviolet (UV-S) radiation and polycyclic aromatic hydrocarbons (PAHs) in bitumen emissions. The combined exposure may lead to photogenotoxicity and enhanced PAH skin permeation rates. Skin permeation rates (J) for selected PAHs in a mixture (PAH-mix) or in bitumen fume condensate (BFC) with and without UV-S co-exposures were measured with in vitro flow-through diffusion cells mounted with human viable skin and results compared. Possible biomarkers were explored. Js were greater with UV-S for naphthalene, anthracene, and pyrene in BFC (0.08-0.1 ng/cm 2 /h) compared to without (0.02-0.26 ng/cm 2 /h). This was true for anthracene, pyrene, and chrysene in the PAH-mix. Naphthalene and benzo(a)pyrene (BaP) in the PAH-mix had greater Js without (0.97-13.01 ng/cm 2 /h) compared to with UV-S (0.40-6.35 ng/cm 2 /h). Time until permeation (T lags ) in the PAH-mix were generally shorter compared to the BFC, and they ranged from 1 to 13 h. The vehicle matrix could potentially be the reason for this discrepancy as BFC contains additional not identified substances. Qualitative interpretation of p53 suggested a dose-response with UV-S, and somewhat with the co-exposures. MMP1, p65 and cKIT were not exploitable. Although not statistically different, PAHs permeate human viable skin faster with simultaneous exposures to UV. Copyright © 2018 Elsevier B.V. All rights reserved.

  2. Carcinogenic and antitumor effects of aminotriazole on acatalasemic and normal catalase mice

    International Nuclear Information System (INIS)

    Feinstein, R.N.; Fry, R.J.M.; Staffeidt, E.F.

    1978-01-01

    Dietary 3-amino-1H-1,2,4-triazole (AT), although carcinogenic when administered alone, was an antitumor agent when combined with certain other carcinogenic stimuli. The carcinogenic effect was prominent in the livers of C3H mice; thyroid tumors were less common because they required a longer period of development, and the life-span of the animal was shortened by the AT diet. The antitumor effects of AT included: delay in appearance of mammary tumors, striking reduction in γ-radiation-induced lymphomas, and sharp reduction in neutron radiation-induced harderian gland and ovarian tumors. On an AT diet, the inbred C3H acatalasemic mouse substrain developed more liver tumors, starting earlier, than did the C3H normal catalase substrain. We suggest that our findings pointed to a possible relevance of catalase and H 2 O 2 in carcinogenesis. The most probable mechanism for the increased incidence of liver tumors in AT-treated acatalasemic mice was the diminished rate of degradation of endogenous H 2 O 2

  3. Skin β-endorphin mediates addiction to UV light.

    Science.gov (United States)

    Fell, Gillian L; Robinson, Kathleen C; Mao, Jianren; Woolf, Clifford J; Fisher, David E

    2014-06-19

    UV light is an established carcinogen, yet evidence suggests that UV-seeking behavior has addictive features. Following UV exposure, epidermal keratinocytes synthesize proopiomelanocortin (POMC) that is processed to melanocyte-stimulating hormone, inducing tanning. We show that, in rodents, another POMC-derived peptide, β-endorphin, is coordinately synthesized in skin, elevating plasma levels after low-dose UV. Increases in pain-related thresholds are observed and reversed by pharmacologic opioid antagonism. Opioid blockade also elicits withdrawal signs after chronic UV exposure. This effect was sufficient to guide operant behavioral choices to avoidance of opioid withdrawal (conditioned place aversion). These UV-induced nociceptive and behavioral effects were absent in β-endorphin knockout mice and in mice lacking p53-mediated POMC induction in epidermal keratinocytes. Although primordial UV addiction, mediated by the hedonic action of β-endorphin and anhedonic effects of withdrawal, may theoretically have enhanced evolutionary vitamin D biosynthesis, it now may contribute to the relentless rise in skin cancer incidence in humans. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. Comparison of the oncogenic potential of several chemotherapeutic agents

    International Nuclear Information System (INIS)

    Miller, R.C.; Hall, E.J.; Osmak, R.S.

    1981-01-01

    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

  5. Patterning of nanoparticulate transparent conductive ITO films using UV light irradiation and UV laser beam writing

    International Nuclear Information System (INIS)

    Solieman, A.; Moharram, A.H.; Aegerter, M.A.

    2010-01-01

    Indium tin oxide (ITO) thin film is one of the most widely used as transparent conductive electrodes in all forms of flat panel display (FPD) and microelectronic devices. Suspension of already crystalline conductive ITO nanoparticles fully dispersed in alcohol was spun, after modifying with coupling agent, on glass substrates. The low cost, simple and versatile traditional photolithography process without complication of the photoresist layer was used for patterning ITO films. Using of UV light irradiation through mask and direct UV laser beam writing resulted in an accurate linear, sharp edge and very smooth patterns. Irradiated ITO film showed a high transparency (∼85%) in the visible region. The electrical sheet resistance decrease with increasing time of exposure to UV light and UV laser. Only 5 min UV light irradiation is enough to decrease the electrical sheet resistance down to 5 kΩ□.

  6. An estimation of the carcinogenic risk associated with the intake of multiple relevant carcinogens found in meat and charcuterie products.

    Science.gov (United States)

    Hernández, Ángel Rodríguez; Boada, Luis D; Almeida-González, Maira; Mendoza, Zenaida; Ruiz-Suárez, Norberto; Valeron, Pilar F; Camacho, María; Zumbado, Manuel; Henríquez-Hernández, Luis A; Luzardo, Octavio P

    2015-05-01

    Numerous epidemiological studies have demonstrated a link between excessive meat consumption and the incidence of various cancers, especially colorectal cancer, and it has been suggested that environmental carcinogens present in meat might be related to the increased risk of cancer associated with this food. However, there are no studies evaluating the carcinogenic potential of meat in relation to its content of carcinogens. Our purpose was to emphasize the relevance of environmental carcinogens existing in meat as a determinant of the association between cancer and meat consumption. Because within Europe, Spain shows high consumption of meat and charcuterie, we performed this study focusing on Spanish population. Based on the preferences of consumers we acquired 100 samples of meat and charcuterie that reflect the variety available in the European market. We quantified in these samples the concentration of 33 chemicals with calculated carcinogenic potential (PAHs, organochlorine pesticides, and dioxin-like PCBs). The carcinogenic risk of these contaminants was assessed for each food using a risk ratio based on the current consumption of meat and charcuterie and the maximum tolerable intake of these foods depending on the level of contamination by the carcinogens they contain. Our results indicate that the current consumption of beef, pork, lamb, chicken, and "chorizo", represents a relevant carcinogenic risk for consumers (carcinogenic risk quotient between 1.33 and 13.98). In order to reduce carcinogenic risk, the study population should halve the monthly consumption of these foods, and also not to surpass the number of 5 servings of beef/pork/chicken (considered together). Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Specific inhibition of cytotoxic memory cells produced against uv-induced tumors in uv-irradiation mice

    International Nuclear Information System (INIS)

    Thorn, R.M.

    1978-01-01

    Cytotoxic responses of uv-irradiated mice against syngeneic uv-induced tumors were measured by using a 51 Cr-release assay to determine if uv treatment induced a specific reduction of cytotoxic activity. The in vivo and in vitro primary responses against syngeneic tumors and allogeneic cells were unaffected, as was the ''memory'' response (in vivo stimulation, in vitro restimulation) against alloantigens. In contrast, the memory response of uv-treated mice against syngeneic, uv-induced tumors was consistently and significantly depressed. The cytotoxicity generated by tumor cell stimulation in vivo or in vitro was tumor-specific and T cell-dependent. Since the primary response against syngeneic uv-induced tumors produces apparently normal amounts of tumor-specific cytotoxic activity, uv-treated mice may not reject transplanted syngeneic tumors because of too few T effector memory cells. These results imply that, at least in this system, tumor rejection depends mostly on the secondary responses against tumor antigens and that at least one carcinogen can, indirectly, specifically regulate immune responses

  8. 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 huma...

  9. Identification and monitoring of non-radiological carcinogens

    Energy Technology Data Exchange (ETDEWEB)

    Chuaqui, C A; Petkau, A; Greenstock, C L; Brown, C P [Atomic Energy of Canada Ltd., Pinawa, MB (Canada). Whiteshell Labs.

    1995-09-01

    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.

  10. Identification and monitoring of non-radiological carcinogens

    International Nuclear Information System (INIS)

    Chuaqui, C.A.; Petkau, A.; Greenstock, C.L.; Brown, C.P.

    1995-09-01

    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

  11. Studies on carcinogenic effect of tritiated water

    International Nuclear Information System (INIS)

    Zou Shuai; Wang Hui; Li Maohe; Lin Suqin

    1994-09-01

    Studies on carcinogenic effect of tritiated water is introduced in two parts. The first part is an in vitro study in which CHL-1 cells were exposed to tritiated water (9.25 x 10 5 ∼ 3.5 x 10 6 Bq/ml) for 24 ∼ 96 h and the accumulated dose was from 0.055 to 0.88 Gy. In order to estimate RBE of tritium for malignant transformation in CHL-1 cells, the induction of malignant transformation in CHL-1 cells by exposure to gamma rays of 137 Cs was tested. Based on the transformation rates, the RBE of tritium for malignant transformation in CHL-1 cells was estimated to be 1.6. The second part is an in vivo study. In the study, rats were fed with tritiated water (2.22 x 10 5 and 1.11 x 10 5 Bq/ml) for 1.5 a. Rats in control group were fed with tap water. Results showed that in the statistics, the differences in the total tumor incidence and malignant tumor incidence between high and low dose rate groups and control groups were remarkably significant

  12. Environmental carcinogens and prophylaxis of malignant tumors

    Energy Technology Data Exchange (ETDEWEB)

    Shabad, L M

    1977-01-01

    A short history of a relatively new branch of cancer research, hygienic oncology, is reviewed. Occupational skin tumors (papillomas and even squamous-cell carcinoma) are described not only among chimney-sweepers, but also among the workers of petroleum refineries. Of 512 workers who had prolonged exposure to various petroleum products, 53.2% developed skin carcinoma. Occupational malignant tumors of the respiratory tract are observed among the workers of nickel industries. Workers who experienced prolonged exposure to asbestos had an increased incidence of lung and stomach cancer. To prevent occuptional cancer of the urinary bladder, such carcinogens as 2-napthylamine, 3,3-dichlorobenzidine, 3,3-dioxybenzidine, and para-amino-azobenzene were banned. Environmental pollution with the products of incomplete fuel combustion, especially with polycyclic aromatic carbohydrates constitutes a hazard to the urban population. The level of benzopyrene (BP) in soil samples taken in different localities averaged 5 microg/kg. Legislatively approved permissible concentrations of BP in the air are 0.1 microg/100 cubic meters, and in the water 0.005 microg/liter. 23 references.

  13. Dehydropyrrolizidine Alkaloid Toxicity, Cytotoxicity, and Carcinogenicity

    Directory of Open Access Journals (Sweden)

    Bryan L. Stegelmeier

    2016-11-01

    Full Text Available Dehydropyrrolizidine alkaloid (DHPA-producing plants have a worldwide distribution amongst flowering plants and commonly cause poisoning of livestock, wildlife, and humans. Previous work has produced considerable understanding of DHPA metabolism, toxicity, species susceptibility, conditions, and routes of exposure, and pathogenesis of acute poisoning. Intoxication is generally caused by contaminated grains, feed, flour, and breads that result in acute, high-dose, short-duration poisoning. Acute poisoning produces hepatic necrosis that is usually confirmed histologically, epidemiologically, and chemically. Less is known about chronic poisoning that may result when plant populations are sporadic, used as tisanes or herbal preparations, or when DHPAs contaminate milk, honey, pollen, or other animal-derived products. Such subclinical exposures may contribute to the development of chronic disease in humans or may be cumulative and probably slowly progress until liver failure. Recent work using rodent models suggest increased neoplastic incidence even with very low DHPA doses of short durations. These concerns have moved some governments to prohibit or limit human exposure to DHPAs. The purpose of this review is to summarize some recent DHPA research, including in vitro and in vivo DHPA toxicity and carcinogenicity reports, and the implications of these findings with respect to diagnosis and prognosis for human and animal health.

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

    International Nuclear Information System (INIS)

    Yun, Taik Koo; Oh, Yeong Ram; Kim, Sung Ho

    1986-12-01

    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)

  15. 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.

  16. Correlation of initiating potency of skin carcinogens with potency to induce resistance to terminal differentiation in cultured mouse keratinocytes

    International Nuclear Information System (INIS)

    Kilkenny, A.E.; Morgan, D.; Spangler, E.F.; Yuspa, S.H.

    1985-01-01

    The induction by chemical carcinogens of resistance to terminal differentiation in cultured mouse keratinocytes has been proposed to represent a cellular change associated with the initiation phase of skin carcinogenesis. Previous results with this culture model indicated that the number of differentiation-resistant foci was correlated with the dose and known potency for several chemical carcinogens. Assay conditions were optimized to provide quantitative results for screening a variety of carcinogens for their potency as inducers of foci resistant to terminal differentiation. Eight skin initiators of varying potency and from different chemical classes and ultraviolet light were studied for their activity to induce this alteration in cultured epidermal cells from newborn BALB/c mice. There was an excellent positive correlation for the potency of these agents as initiators in vivo and as inducers of altered differentiation in vitro. The induction of resistant foci was independent of the relative cytotoxic effects of each agent except where cytotoxicity was extensive and reduced the number of foci. The results support the hypothesis that initiation of carcinogenesis in skin results in an alteration in the program of epidermal cell differentiation. The results also suggest that the assay is useful for identifying relative potency classes (strong, moderate, weak) of initiating agents

  17. An overview of advanced reduction processes for bromate removal from drinking water: Reducing agents, activation methods, applications and mechanisms.

    Science.gov (United States)

    Xiao, Qian; Yu, Shuili; Li, Lei; Wang, Ting; Liao, Xinlei; Ye, Yubing

    2017-02-15

    Bromate (BrO 3 - ) is a possible human carcinogen regulated at a strict standard of 10μg/L in drinking water. Various techniques to eliminate BrO 3 - usually fall into three main categories: reducing bromide (Br - ) prior to formation of BrO 3 - , minimizing BrO 3 - formation during the ozonation process, and removing BrO 3 - from post-ozonation waters. However, the first two approaches exhibit low degradation efficiency and high treatment cost. The third workaround has obvious advantages, such as high reduction efficiency, more stable performance and easier combination with UV disinfection, and has therefore been widely implemented in water treatment. Recently, advanced reduction processes (ARPs), the photocatalysis of BrO 3 - , have attracted much attention due to improved performance. To increase the feasibility of photocatalytic systems, the focus of this work concerns new technological developments, followed by a summary of reducing agents, activation methods, operational parameters, and applications. The reaction mechanisms of two typical processes involving UV/sulfite homogeneous photocatalysis and UV/titanium dioxide heterogeneous photocatalysis are further summarized. The future research needs for ARPs to reach full-scale potential in drinking water treatment are suggested accordingly. Copyright © 2016. Published by Elsevier B.V.

  18. Deconjugation of N-glucuronide conjugated metabolites with hydrazine hydrate - Biomarkers for exposure to the food-borne carcinogen 2-amino-l-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP)

    DEFF Research Database (Denmark)

    Frandsen, Henrik Lauritz

    2007-01-01

    The metabolism of the carcinogen 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) has been investigated in rabbit liver S9. Two phase I metabolites, N-2-OH-PhIP and 4'-OH-PhIP were identified based on UV and mass spectra and co-elution with reference standards. Fortification of the incubation...

  19. Enhanced replication of damaged SV40 DNA in carcinogen-treated monkey cells

    International Nuclear Information System (INIS)

    Maga, J.A.; Dixon, K.

    1984-01-01

    Treatment of mammalian cells with certain chemical or physical carcinogens prior to infection with ultraviolet-irradiated virus results in enhanced survival or reactivation of the damaged virus. To investigate the molecular basis of this enhanced reactivation (ER), Simian virus 40 DNA replication in carcinogen-treated cells was examined. Treatment of monkey kidney cells with N-acetoxy-2-acetylamino-fluorene or UV radiation 24 h prior to infection with ultraviolet-irradiated Simian virus 40 leads to enhancement of viral DNA replication measured at 36 h after infection by [ 3 H]thymidine incorporation or hybridization. The enhancement of DNA replication is observed when cells are treated from 1 to 60 h before infection or 1 to 16 h after infection. The fact that enhancement is observed also when cells are treated after infection rules out the possiblity that enhancement occurs at the level of adsorption or penetration of the virus. Measurements of the time course of viral DNA replication indicate that pretreatment of cells does not alter the time of onset of viral DNA replication. It is concluded that ER of Simain virus 40 occurs at the level of viral DNA replication. (author)

  20. Foetal exposure to food and environmental carcinogens in human beings.

    Science.gov (United States)

    Myöhänen, Kirsi; Vähäkangas, Kirsi

    2012-02-01

    Exposure to many different chemicals during pregnancy through maternal circulation is possible. Transplacental transfer of xenobiotics can be demonstrated using human placental perfusion. Also, placental perfusion can give information about the placental kinetics as well as metabolism and accumulation in the placenta because it retains the tissue structure and function. Although human placental perfusion has been used extensively to study the transplacental transfer of drugs, the information on food and environmental carcinogens is much more limited. This review deals with the foetal exposure to food and environmental carcinogens in human beings. In particular, human transplacental transfer of the food carcinogens such as acrylamide, glycidamide and nitrosodimethylamine are in focus. Because these carcinogens are genotoxic, the functional capacity of human placenta to induce DNA adduct formation or metabolize these above mentioned CYP2E1 substrates is of interest in this context. © 2011 The Authors. Basic & Clinical Pharmacology & Toxicology © 2011 Nordic Pharmacological Society.

  1. Carcinogenicity tests of certain environmental and industrial chemicals

    International Nuclear Information System (INIS)

    Weisburger, E.K.; Ulland, B.M.; Nam, J.; Gart, J.J.; Weisburger, J.H.

    1981-01-01

    Fourteen chemicals of varied uses were tested for carcinogenicity by oral administration in male and female Charles River CD rats. Under the conditions of the tests, propane sultone, propylene imine, and ethylenethiourea, in addition to the positive control N-2-fluorenylacetamide, were carcinogenic. Avadex, bis(2-chloroethyl) ether, the potassium salt of bis(2-hydroxyethyl) dithiocarbamic acid, ethylene carbonate, and semicarbazide hydrochloride were not carcinogenic under the test conditions. Dithiooxamide, glycerol alpha-monochlorohydrin, and thiosemicarbazide gave somewhat ambiguous results, though administered at high enough dose levels to be toxic. An inadequate number of animals survived treatments with sodium azide, sodium bisulfide, and vinylene carbonate, or the animals may not have received sufficiently high doses of the test chemicals to provide maximum test sensitivity. However, there were no indications that these three chemicals were carcinogenic under the test conditions

  2. Determination of seven sunscreen agents and two ultraviolet stabilizers in skin care products using ultra-performance liquid chromatography.

    Science.gov (United States)

    Gowell, Aimee; Habel, John; Weiss, Caryn; Parkanzky, Paul

    2015-01-01

    Ultraviolet radiation (UVR) is a well-known environmental carcinogen. Protection against UVR exposure has resulted in an increasing number of sunscreen agents being incorporated into a greater variety of cosmetic formulations including moisturizing lotions, color cosmetics, and skin care creams. Meanwhile, global regulation of sun care products is changing. New guidelines for sunscreen efficacy have resulted in a shift in product formulation that requires sunscreen products to provide broad spectrum UV protection. Since not all sunscreen ingredients protect against both UVA and UVB radiation, most sun care products require a combination of sunscreen agents. This article describes a new method for simultaneous separation and quantitation of seven organic sunscreens and two UV stabilizers using ultra-performance liquid chromatography. This method is capable of resolving all nine analytes, and has been validated for selectivity, precision, and accuracy. Because of the use of core-shell column technology, the separation is also achieved at back pressures compatible with conventional high-performance liquid chromatography instrumentation.

  3. Relative potency estimation for synthetic petroleum skin carcinogens.

    OpenAIRE

    Holland, J M; Wolf, D A; Clark, B R

    1981-01-01

    A procedure for quantitative analysis of skin carcinogenesis data, for the purpose of establishing carcinogenic potency, has been applied to observations obtained from C3H mice exposed continuously to synthetic and natural petroleums. The importance of total polynuclear aromatic (PNA) content to the skin carcinogenic activity of the crude materials was also examined. Of three synthetic petroleums evaluated, all were shown capable of inducing skin neoplasms within a two-year exposure period. U...

  4. Comets in UV

    Science.gov (United States)

    Shustov, B.; Sachkov, M.; Gómez de Castro, A. I.; Vallejo, J. C.; Kanev, E.; Dorofeeva, V.

    2018-04-01

    Comets are important "eyewitnesses" of Solar System formation and evolution. Important tests to determine the chemical composition and to study the physical processes in cometary nuclei and coma need data in the UV range of the electromagnetic spectrum. Comprehensive and complete studies require additional ground-based observations and in situ experiments. We briefly review observations of comets in the ultraviolet (UV) and discuss the prospects of UV observations of comets and exocomets with space-borne instruments. A special reference is made to the World Space Observatory-Ultraviolet (WSO-UV) project.

  5. Hexavalent chrome: threshold concept for carcinogenicity.

    Science.gov (United States)

    Jones, R E

    1990-03-01

    Certain hexavalent chromium (Cr6+) compounds when administered via inhalation at high doses have the potential to induce lung tumors in humans and experimental animals. Trivalent chromium (Cr3+) is an essential human and animal nutrient at levels of 50 to 200 micrograms/day. Recent data have shown that the human body is able to reduce Cr6+ to Cr3+. This reduction occurs in bodily fluids such as gastric juice, epithelial lining fluid of the respiratory tract, blood, and other fluids. Secondary reduction occurs at the cellular level by the cytosol, mitochondria, and microsomes. Thus, at low levels of exposure hexavalent chromium ions are reduced before the 6+ ions can interact with DNA unless the dose is sufficient to overwhelm the body's reduction capacity. This paper summarizes the available data concerning the reducing ability of the body and formulates the steps in the mechanism of cancer induction. These steps include: (1) only certain Cr6+ compounds have the capacity to interact with cellular components; (2) Cr6+ is reduced by body fluids and excess Cr6+ enters the cell (Cr3+ is poorly absorbed across membranes); (3) cellular organelles and the cytoplasm reduce Cr6+ to Cr3+; (4) excess Cr6+ can enter the nucleus; (5) Cr6+ reduction through 5+ and 4+ to 3+ has a potential to interact with the DNA molecule; and (6) if unrepaired, this DNA damage can lead to cancer induction. On the basis of current evidence Cr6+ has a threshold for carcinogenic potential in humans that is greater than the current TLV.

  6. Lunasin-aspirin combination against NIH/3T3 cells transformation induced by chemical carcinogens.

    Science.gov (United States)

    Hsieh, Chia-Chien; Hernández-Ledesma, Blanca; de Lumen, Ben O

    2011-06-01

    Carcinogenesis is a multistage process involving a number of molecular pathways sensitive to intervention. Chemoprevention is defined as the use of natural and/or synthetic substances to block, reverse, or retard the process of carcinogenesis. To achieve greater inhibitory effects on cancer cells, combination of two or more chemopreventive agents is commonly considered as a better preventive and/or therapeutic strategy. Lunasin is a promising cancer preventive peptide identified in soybean and other seeds. Its efficacy has been demonstrated by both in vitro and in vivo models. This peptide has been found to inhibit human breast cancer MDA-MB-231 cells proliferation, suppressing cell cycle progress and inducing cell apoptosis. Moreover, lunasin potentiates the effects on these cells of different synthetic and natural compounds, such as aspirin and anacardic acid. This study explored the role of lunasin, alone and in combination with aspirin and anacardic acid on cell proliferation and foci formation of transformed NIH/3T3 cells induced by chemical carcinogens 7,12-dimethylbenz[a]anthracene or 3-methylcholanthrene. The results revealed that lunasin, acting as a single agent, inhibits cell proliferation and foci formation. When combined with aspirin, these effects were significantly increased, indicating that this combination might be a promising strategy to prevent/treat cancer induced by chemical carcinogens.

  7. The Food and Beverage Occurrence of Furfuryl Alcohol and Myrcene-Two Emerging Potential Human Carcinogens?

    Science.gov (United States)

    Okaru, Alex O; Lachenmeier, Dirk W

    2017-03-11

    For decades, compounds present in foods and beverages have been implicated in the etiology of human cancers. The World Health Organization (WHO) International Agency for Research on Cancer (IARC) continues to classify such agents regarding their potential carcinogenicity in humans based on new evidence from animal and human studies. Furfuryl alcohol and β-myrcene are potential human carcinogens due to be evaluated. The major source of furfuryl alcohol in foods is thermal processing and ageing of alcoholic beverages, while β-myrcene occurs naturally as a constituent of the essential oils of plants such as hops, lemongrass, and derived products. This study aimed to summarize the occurrence of furfuryl alcohol and β-myrcene in foods and beverages using literature review data. Additionally, results of furfuryl alcohol occurrence from our own nuclear magnetic resonance (NMR) analysis are included. The highest content of furfuryl alcohol was found in coffee beans (>100 mg/kg) and in some fish products (about 10 mg/kg), while among beverages, wines contained between 1 and 10 mg/L, with 8 mg/L in pineapple juice. The content of β-myrcene was highest in hops. In conclusion, the data about the occurrence of the two agents is currently judged as insufficient for exposure and risk assessment. The results of this study point out the food and beverage groups that may be considered for future monitoring of furfuryl alcohol and β-myrcene.

  8. The Food and Beverage Occurrence of Furfuryl Alcohol and Myrcene—Two Emerging Potential Human Carcinogens?

    Directory of Open Access Journals (Sweden)

    Alex O. Okaru

    2017-03-01

    Full Text Available For decades, compounds present in foods and beverages have been implicated in the etiology of human cancers. The World Health Organization (WHO International Agency for Research on Cancer (IARC continues to classify such agents regarding their potential carcinogenicity in humans based on new evidence from animal and human studies. Furfuryl alcohol and β-myrcene are potential human carcinogens due to be evaluated. The major source of furfuryl alcohol in foods is thermal processing and ageing of alcoholic beverages, while β-myrcene occurs naturally as a constituent of the essential oils of plants such as hops, lemongrass, and derived products. This study aimed to summarize the occurrence of furfuryl alcohol and β-myrcene in foods and beverages using literature review data. Additionally, results of furfuryl alcohol occurrence from our own nuclear magnetic resonance (NMR analysis are included. The highest content of furfuryl alcohol was found in coffee beans (>100 mg/kg and in some fish products (about 10 mg/kg, while among beverages, wines contained between 1 and 10 mg/L, with 8 mg/L in pineapple juice. The content of β-myrcene was highest in hops. In conclusion, the data about the occurrence of the two agents is currently judged as insufficient for exposure and risk assessment. The results of this study point out the food and beverage groups that may be considered for future monitoring of furfuryl alcohol and β-myrcene.

  9. Carcinogenic and mutagenic properties of chemicals in drinking water

    Energy Technology Data Exchange (ETDEWEB)

    Bull, R J

    1985-12-01

    Isolated cases of careless handling of industrial and domestic waste has lead to a wide variety of dangerous chemicals being inadvertently introduced into drinking water. However, chemicals with established carcinogenic and mutagenic properties that occur with a high frequency and in multiple locations are limited in number. To date, the chief offenders have been chemicals of relatively low carcinogenic potency. Some of the more common chemicals are formed as by-products of disinfection. The latter process is generally regarded as essential to the production of a ''microbiologically safe'' drinking water. Consequently, any reductions in what may be a relatively small carcinogenic risk must be balanced against a potential for a higher frequency of waterborne infectious disease. The results of recent toxicological investigations will be reviewed to place the potential carcinogenic and mutagenic hazards frequently associated with drinking water into perspective. First, evidence for the carcinogenicity of certain volatile organic compounds such as trichloroethylene, tetrachloroethylene and carbon tetrachloride is considered. Second, the carcinogenic activity that can be ascribed to various by-products of chlorination is reviewed in some detail. Finally, recent evidence that other chemicals derived from the treatment and distribution of drinking water is highlighted as an area requiring move systematic attention. 72 references.

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

    Science.gov (United States)

    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 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 forming the scientific bases for the IARC classification. Exposure to TCE from environmental sources (including hazardous waste sites and contaminated water) is common throughout the world. While workplace use of TCE has been declining, occupational exposures remain of concern, especially in developing countries. The strongest human evidence is from studies of occupational TCE exposure and kidney cancer. Positive, although less consistent, associations were reported for liver cancer and non-Hodgkin lymphoma. TCE is carcinogenic at multiple sites in multiple species and strains of experimental animals. The mechanistic evidence includes extensive data on the toxicokinetics and genotoxicity of TCE and its metabolites. Together, available evidence provided a cohesive database supporting the human cancer hazard of TCE, particularly in the kidney. For other target sites of carcinogenicity, mechanistic and other data were found to be more limited. Important sources of susceptibility to TCE toxicity and carcinogenicity were also reviewed by the Working Group. In all, consideration of the multiple evidence streams presented herein informed the IARC conclusions regarding the carcinogenicity of TCE. © 2013.

  11. Is ionizing radiation regulated more stringently than chemical carcinogens

    International Nuclear Information System (INIS)

    Travis, C.C.; Pack, S.R.; Hattemer-Frey, H.A.

    1989-01-01

    It is widely believed that United States government agencies regulate exposure to ionizing radiation more stringently than exposure to chemical carcinogens. It is difficult to verify this perception, however, because chemical carcinogens and ionizing radiation are regulated using vastly different strategies. Chemical carcinogens are generally regulated individually. Regulators consider the risk of exposure to one chemical rather than the cumulative radiation exposure from all sources. Moreover, standards for chemical carcinogens are generally set in terms of quantities released or resultant environmental concentrations, while standards for ionizing radiation are set in terms of dose to the human body. Since chemicals and ionizing radiation cannot be compared on the basis of equal dose to the exposed individual, standards regulating chemicals and ionizing radiation cannot be compared directly. It is feasible, however, to compare the two sets of standards on the basis of equal risk to the exposed individual, assuming that standards for chemicals and ionizing radiation are equivalent if estimated risk levels are equitable. This paper compares risk levels associated with current standards for ionizing radiation and chemical carcinogens. The authors do not attempt to determine whether either type of risk is regulated too stringently or not stringently enough but endeavor only to ascertain if ionizing radiation is actually regulated more strictly than chemical carcinogens

  12. 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)

    Sun Yang; 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 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/cm 2 ) 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.

  13. UV exposure in cars.

    Science.gov (United States)

    Moehrle, Matthias; Soballa, Martin; Korn, Manfred

    2003-08-01

    There is increasing knowledge about the hazards of solar and ultraviolet (UV) radiation to humans. Although people spend a significant time in cars, data on UV exposure during traveling are lacking. The aim of this study was to obtain basic information on personal UV exposure in cars. UV transmission of car glass samples, windscreen, side and back windows and sunroof, was determined. UV exposure of passengers was evaluated in seven German middle-class cars, fitted with three different types of car windows. UV doses were measured with open or closed windows/sunroof of Mercedes-Benz E 220 T, E 320, and S 500, and in an open convertible car (Mercedes-Benz CLK). Bacillus subtilis spore film dosimeters (Viospor) were attached to the front, vertex, cheeks, upper arms, forearms and thighs of 'adult' and 'child' dummies. UV wavelengths longer than >335 nm were transmitted through car windows, and UV irradiation >380 nm was transmitted through compound glass windscreens. There was some variation in the spectral transmission of side windows according to the type of glass. On the arms, UV exposure was 3-4% of ambient radiation when the car windows were shut, and 25-31% of ambient radiation when the windows were open. In the open convertible car, the relative personal doses reached 62% of ambient radiation. The car glass types examined offer substantial protection against short-wave UV radiation. Professional drivers should keep car windows closed on sunny days to reduce occupational UV exposure. In individuals with polymorphic light eruption, produced by long-wave UVA, additional protection by plastic films, clothes or sunscreens appears necessary.

  14. 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

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

    International Nuclear Information System (INIS)

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

    2014-01-01

    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

  16. Bromate formation from the oxidation of bromide in the UV/chlorine process with low pressure and medium pressure UV lamps.

    Science.gov (United States)

    Fang, Jingyun; Zhao, Quan; Fan, Chihhao; Shang, Chii; Fu, Yun; Zhang, Xiangru

    2017-09-01

    When a bromide-containing water is treated by the ultraviolet (UV)/chlorine process, hydroxyl radicals (HO) and halogen radicals such as Cl or Br are formed due to the UV photolysis of free halogens. These reactive species may induce the formation of bromate, which is a probable human carcinogen. Bromate formation in the UV/chlorine process using low pressure (LP) and medium pressure (MP) lamps in the presence of bromide was investigated in the present study. The UV/chlorine process significantly enhanced bromate formation as compared to dark chlorination. The bromate formation was elevated with increasing UV fluence, bromide concentration, and pH values under both LP and MP UV irradiations. It was significantly enhanced at pH 9 compared to those at pH 6 and 7 with MP UV irradiation, while it was slightly enhanced at pH 9 with LP UV. The formation by UV/chlorine process started with the formation of free bromine (HOBr/OBr - ) through the reaction of chlorine and bromide, followed by a subsequent oxidation of free bromine and formation of BrO and bromate by reacting with radicals. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. 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

  18. Is UV-A radiation a cause of malignant melanoma?

    International Nuclear Information System (INIS)

    Moan, J.

    1994-01-01

    The first action spectrum for cutaneous malignant melanoma was published recently. This spectrum was obtained using the fish Xiphophorus. If the same action spectrum applies to humans, the following statements are true: Sunbathing products (agents to protect against the sun) that absorb UV-B radiation provide almost no protection against cutaneous malignant melanoma. UV-A-solaria are more dangerous than expected so far. If people are determined to use artificial sources of radiation for tanning, they should choose UV-B solaria rather than UV-A-solaria. Fluorescent tubes and halogen lamps may have weak melanomagenic effects. Ozone depletion has almost no effect on the incidence rates of CMM, since ozone absorbs very little UV-A radiation. Sunbathing products which contain UV-A-absorbing compounds or neutral filter (like titanium oxide) provide real protection against cutaneous malignant melanoma, at least if they are photochemically inert. 34 refs., 2 figs

  19. Carcinogenicity of methyl-tertiary butyl ether in gasoline.

    Science.gov (United States)

    Mehlman, Myron A

    2002-12-01

    Methyl tertiary butyl ether (MTBE) was added to gasoline on a nationwide scale in 1992 without prior testing of adverse, toxic, or carcinogenic effects. Since that time, numerous reports have appeared describing adverse health effects of individuals exposed to MTBE, both from inhalation of fumes in the workplace and while pumping gasoline. Leakage of MTBE, a highly water-soluble compound, from underground storage tanks has led to contamination of the water supply in many areas of the United States. Legislation has been passed by many states to prohibit the addition of MTBE to gasoline. The addition of MTBE to gasoline has not accomplished its stated goal of decreasing air pollution, and it has posed serious health risks to a large portion of the population, particularly the elderly and those with respiratory problems, asthma, and skin sensitivity. Reports of animal studies of carcinogenicity of MTBE began to appear in the 1990s, prior to the widespread introduction of MTBE into gasoline. These reports were largely ignored. In ensuing years, further studies have shown that MTBE causes various types of malignant tumors in mice and rats. The National Toxicology Program (NTP) Board of Scientific Counselors' Report on Carcinogens Subcommittee met in December 1998 to consider listing MTBE as "reasonably anticipated to be a human carcinogen." In spite of recommendations from Dr. Bailer, the primary reviewer, and other scientists on the committee, the motion to list MTBE in the report was defeated by a six to five vote, with one abstention. On the basis of animal studies, it is widely accepted that if a chemical is carcinogenic in appropriate laboratory animal test systems, it must be treated as though it were carcinogenic in humans. In the face of compelling evidence, NTP Committee members who voted not to list MTBE as "reasonably anticipated to be a human carcinogen" did a disservice to the general public; this action may cause needless exposure of many to health risks

  20. Effect of arsenite on the DNA repair of UV-irradiated Chinese hamster ovary cells

    Energy Technology Data Exchange (ETDEWEB)

    Lee-Chen, S.F.; Yu, C.T.; Jan, K.Y. (Academia Sinica, Taipei, (Taiwan). Institute of Zoology)

    1992-01-01

    Arsenite, an ubiquitous human carcinogen, has been shown to enhance the cytotoxicity, mutagenicity and clastogenicity of UV light in mammalian cells. Arsenite may exert its co-genotoxic effects by inhibiting DNA repair. Results from alkaline sucrose gradient sedimentation show that arsenite did not accumulate UV-induced DNA strand breaks in Chinese hamster ovary (CHO) K1 cells as aphidicolin plus hydroxyurea (HU) did. These data indicate that arsenite did not inhibit the activity of DNA polymerase [alpha] in UV repair. Treatment with arsenite before UV irradiation slightly reduced the DNA strand breaks accumulated by cytosine [beta]-D-arabinofuranoside (AraC) plus HU. This effect implies that arsenite only slightly inhibited the incision of UV-induced DNA adducts. The low molecular weight DNA accumulated by post-UV incubation with AraC plus HU shifted to high molecular weight upon the incubation of cells in drug-free medium, but this shifting was prohibited by the presence of arsenite. This suggests that arsenite inhibited the rejoining of DNA strand breaks. When a pulse-chase labelling procedure was applied on UV-irradiated cells, the chain elongation of nascent DNA was strongly inhibited by post-incubation with arsenite. These data show that arsenite inhibited post-replication repair in UV-irradiated cells. Therefore, the steps inhibited by arsenite in UV-induced cells. Therefore, the steps inhibited by arsenite in UV-induced DNA repair in CHO K1 cells are different from human fibroblasts. (author).

  1. Effect of arsenite on the DNA repair of UV-irradiated Chinese hamster ovary cells

    International Nuclear Information System (INIS)

    Lee-Chen, S.F.; Yu, C.T.; Jan, K.Y.

    1992-01-01

    Arsenite, an ubiquitous human carcinogen, has been shown to enhance the cytotoxicity, mutagenicity and clastogenicity of UV light in mammalian cells. Arsenite may exert its co-genotoxic effects by inhibiting DNA repair. Results from alkaline sucrose gradient sedimentation show that arsenite did not accumulate UV-induced DNA strand breaks in Chinese hamster ovary (CHO) K1 cells as aphidicolin plus hydroxyurea (HU) did. These data indicate that arsenite did not inhibit the activity of DNA polymerase α in UV repair. Treatment with arsenite before UV irradiation slightly reduced the DNA strand breaks accumulated by cytosine β-D-arabinofuranoside (AraC) plus HU. This effect implies that arsenite only slightly inhibited the incision of UV-induced DNA adducts. The low molecular weight DNA accumulated by post-UV incubation with AraC plus HU shifted to high molecular weight upon the incubation of cells in drug-free medium, but this shifting was prohibited by the presence of arsenite. This suggests that arsenite inhibited the rejoining of DNA strand breaks. When a pulse-chase labelling procedure was applied on UV-irradiated cells, the chain elongation of nascent DNA was strongly inhibited by post-incubation with arsenite. These data show that arsenite inhibited post-replication repair in UV-irradiated cells. Therefore, the steps inhibited by arsenite in UV-induced cells. Therefore, the steps inhibited by arsenite in UV-induced DNA repair in CHO K1 cells are different from human fibroblasts. (author)

  2. Furan formation from fatty acids as a result of storage, gamma irradiation, UV-C and heat treatments

    Science.gov (United States)

    Furan is a possible human carcinogen that has been found in many thermally processed foods. The effects of thermal processing, gamma and UV-C irradiation on formation of furan from different fatty acids was studied. In addition, formation of furan from fatty acid emulsions during storage at 25C and...

  3. Biological Agents

    Science.gov (United States)

    ... E-Tools Safety and Health Topics / Biological Agents Biological Agents This page requires that javascript be enabled ... 202) 693-2300 if additional assistance is required. Biological Agents Menu Overview In Focus: Ebola Frederick A. ...

  4. Is UV-A radiation a cause of malignant melanoma. Er UV-A aarsak til malignt melanom

    Energy Technology Data Exchange (ETDEWEB)

    Moan, J. (Det Norske Radiumhospital, Oslo (Norway))

    1994-03-01

    The first action spectrum for cutaneous malignant melanoma was published recently. This spectrum was obtained using the fish Xiphophorus. If the same action spectrum applies to humans, the following statements are true: Sunbathing products (agents to protect against the sun) that absorb UV-B radiation provide almost no protection against cutaneous malignant melanoma. UV-A-solaria are more dangerous than expected so far. If people are determined to use artificial sources of radiation for tanning, they should choose UV-B solaria rather than UV-A-solaria. Fluorescent tubes and halogen lamps may have weak melanomagenic effects. Ozone depletion has almost no effect on the incidence rates of CMM, since ozone absorbs very little UV-A radiation. Sunbathing products which contain UV-A-absorbing compounds or neutral filter (like titanium oxide) provide real protection against cutaneous malignant melanoma, at least if they are photochemically inert. 34 refs., 2 figs.

  5. Risk assessment of DNA-reactive carcinogens in food.

    Science.gov (United States)

    Jeffrey, A M; Williams, G M

    2005-09-01

    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 B(1) (AFB(1)), a limit of 20 ppb or approximately 30 microg/day has been set and is considered a tolerable daily intake (TDI). Since AFB(1) is considered a potent carcinogen, doses of carcinogens is made.

  6. Inhibiting the regeneration of N-nitrosodimethylamine in drinking water by UV photolysis combined with ozonation

    Energy Technology Data Exchange (ETDEWEB)

    Bingbing, Xu [State Key Laboratory of Urban Water Resource and Environment, School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin, 150090 (China); State Environmental Protection Key Laboratory for Lake Pollution Control, Chinese Research Academy of Environmental Sciences, Beijing, 100012 (China); Chen Zhonglin, E-mail: zhonglinchen@263.net [State Key Laboratory of Urban Water Resource and Environment, School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin, 150090 (China); Fei, Qi [College of Environmental Science and Engineering, Beijing Forestry University, Beijing, 100083 (China); Jun, Ma [State Key Laboratory of Urban Water Resource and Environment, School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin, 150090 (China); Fengchang, Wu [State Environmental Protection Key Laboratory for Lake Pollution Control, Chinese Research Academy of Environmental Sciences, Beijing, 100012 (China)

    2009-08-30

    N-Nitrosodimethylamine (NDMA) is a highly carcinogenic compound that is suspected of carcinogenic activity in the human body. A variety of methods are used to remove NDMA from water, but the main degradation products, dimethylamine (DMA) and NO{sub 2}{sup -}, are also precursors for NDMA formation. UV irradiation combined with ozonation (UV/O{sub 3}) was examined in this investigation for its ability to inhibit the regeneration of NDMA after degradation. Both the degradation products and the regeneration potential of NDMA were compared between UV irradiation alone and UV/O{sub 3}. The yields of DMA and NO{sub 2}{sup -} in the UV/O{sub 3} process were less than for UV irradiation alone. Yields of DMA and NO{sub 2}{sup -} were 2.25 mg L{sup -1} and 3.22 mg L{sup -1} from UV irradiation, while they were 0.92 mg L{sup -1} and 0.45 mg L{sup -1} from the UV/O{sub 3} process. Furthermore, the regeneration of NDMA was also less after the UV/O{sub 3} process than after UV irradiation. The concentration of regenerated NDMA was more than 51.8 {mu}g L{sup -1} after UV irradiation regardless of the dosage of Cl{sub 2}. However, the concentration of regenerated NDMA in the UV/O{sub 3} process was less than 7.37 {mu}g L{sup -1} under the same conditions. Consequently, the UV/O{sub 3} process was more effective than UV irradiation alone in inhibiting NDMA regeneration. The inhibition of NDMA regeneration was due to a decrease in DMA and NO{sub 2}{sup -} produced by the UV/O{sub 3} process. As the major products generated from NDMA, NO{sub 2}{sup -} and DMA were likely to be oxidized by ozone and hydroxyl radicals ({center_dot}OH). In addition, the reaction between NDMA and {center_dot}OH would possibly generate methylamine as the only product, leading to a decrease in the production of DMA by the UV/O{sub 3} process.

  7. UV disinfection of water

    International Nuclear Information System (INIS)

    Skipperud, E.; Johansen; Myhrstad, J.A.

    1978-01-01

    UV radiation has been found to have advantages over chloration for the disinfection of water. New regulations for dietary conditions on Norwegian ships introduced in 1974 led to increased use of UV disinfection, and this has in the following years spread to waterworks. The present article is based on a study to determine possible limitation. The nature of the injuries to the microorganisms is first discussed, together with repair mechanisms. A table is given showing the energy required for 90 and 100 percent inactivation of a number of microorganisms. Some other factors affecting UV inactivation are briefly mentioned. (JIW)

  8. 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.

  9. 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

  10. Indoor air - assessment: Methods of analysis for environmental carcinogens

    International Nuclear Information System (INIS)

    Peterson, M.R.; Naugle, D.F.; Berry, M.A.

    1990-06-01

    The monograph describes, in a general way, published sampling procedures and analytical approaches for known and suspected carcinogens. The primary focus is upon carcinogens found in indoor air, although the methods described are applicable to other media or environments. In cases where there are no published methods for a particular pollutant in indoor air, methods developed for the workplace and for ambient air are included since they should be adaptable to indoor air. Known and suspected carcinogens have been grouped into six categories for the purposes of this and related work. The categories are radon, asbestos, organic compounds, inorganic species, particles, and non-ionizing radiation. Some methods of assessing exposure that are not specific to any particular pollutant category are covered in a separate section. The report is the fifth in a series of EPA/Environmental Criteria and Assessment Office Monographs

  11. Biomonitoring human exposure to environmental carcinogenic chemicals

    DEFF Research Database (Denmark)

    Farmer, P.B.; Sepai, O.; Lawrence, R.

    1996-01-01

    A coordinated study was carried out on the development, evaluation and application of biomonitoring procedures for populations exposed to environmental genotoxic pollutants. The procedures used involved both direct measurement of DNA or protein damage (adducts) and assessment of second biological...... spectrometry). The measurement of adducts was focused on those from genotoxicants that result from petrochemical combustion or processing, e.g. low-molecular-weight alkylating agents, PAHs and compounds that cause oxidative DNA damage. Cytogenetic analysis of lymphocytes was undertaken (micronuclei, chromosome...... aberrations and sister chromatid exchanges) and mutation frequency was estimated at a number of loci including the hprt gene and genes involving in cancer development. Blood and urine samples from individuals exposed to urban pollution were collected. Populations exposed through occupational or medical...

  12. Carcinogenic effect of petroleum and its by-products

    Energy Technology Data Exchange (ETDEWEB)

    Gimadeev, M M

    1962-01-01

    A review of literature on the carcinogenic effect of petroleum and its by-products are briefly discussed. Many of the products can induce hyperkeratosis, folliculitis, verruca, pulmonary adenoma, skin cancer, etc. Their action is mainly local but they can also be multicentric. Although a number of groups have made chemical analyses of various petroleums and peroleum products, results were generally negative with respect to 3,4-benzypyrene, although 40 to 68 microg/g was found in 1 crude petroleum. At present it appears that much of the carcinogenic action of these materials resides in polycyclic hydrocarbons about which little is known.

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

    International Nuclear Information System (INIS)

    Hsu, I.C.

    1987-01-01

    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, 0 6 -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

  14. 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.

  15. Mutagenic and carcinogenic structural alerts and their mechanisms of action.

    Science.gov (United States)

    Plošnik, Alja; Vračko, Marjan; Dolenc, Marija Sollner

    2016-09-01

    Knowing the mutagenic and carcinogenic properties of chemicals is very important for their hazard (and risk) assessment. One of the crucial events that trigger genotoxic and sometimes carcinogenic effects is the forming of adducts between chemical compounds and nucleic acids and histones. This review takes a look at the mechanisms related to specific functional groups (structural alerts or toxicophores) that may trigger genotoxic or epigenetic effects in the cells. We present up-to-date information about defined structural alerts with their mechanisms and the software based on this knowledge (QSAR models and classification schemes).

  16. Modification of carcinogenic and antitumor radiation effects (biomedical aspects)

    International Nuclear Information System (INIS)

    Vilenchik, M.M.

    1985-01-01

    In the book the data on modification of carcinogenic radiation effects by physiologicaly active compounds (caffeine, hormones, promoters and others) as well as on potentiation of antitumor radiation effects by means of hyperthermia are systematized. It is shown that as a basis of synergetic (superadditive) carcinogenic or antitumor radiation effects combined with other factor can be the inhibiting effects of the latter on the reparation process of radiation-induced DNA injuries. The results of experimental investigations and the data on quantitative analysis can be used as a theoretical basis for improvement of the ways and means of the prophylaxis of tumor diseases as well as for increasing the efficiency of radiotherapy

  17. A call to expand regulation to all carcinogenic fibrous minerals

    Science.gov (United States)

    Baumann, F.; Steele, I.; Ambrosi, J.; Carbone, M.

    2013-05-01

    The regulatory term "asbestos" groups only the six fibrous minerals that were commercially used among approximately 400. The carcinogenicity of these six regulated minerals has been largely demonstrated and is related to fiber structure, fiber length/diameter ratio, and bio-persistence. From a public perception, the generic term "asbestos" refers to the fibrous minerals that cause asbestosis, mesothelioma and other cancers. However, other non-regulated fibrous minerals are potentially as dangerous as the regulatory asbestos because they share similar physical and chemical properties, epidemiological studies have demonstrated their relationship with asbestos-related diseases, and both in vitro and in vivo experiments have established the toxicity of these minerals. For example, the non-regulated asbestiform winchite and richterite minerals that contaminated the vermiculite mined from Libby, Montana, (USA) were associated with mesothelioma, lung cancer and asbestosis observed among the area's residents and miners. Many other examples of non-regulated carcinogenic fibrous minerals include, but are not limited to, antigorite, arfvedsonite, balangeroite, carlosturanite, erionite, fluoro-edenite, hornblende, mordenite, palygorskite, and sepiolite. To propose a regulatory definition that would provide protection from all carcinogenic fibers, we have conducted an interdisciplinary literature review to compare the characteristics of "asbestos" and of non-regulated mineral fibers that relate to carcinogenicity. We specifically studied two non-regulated fibrous minerals that are associated with asbestos-related diseases: the serpentine antigorite and the zeolite erionite. Both examples underscore the problem of regulation based on commercial, rather than scientific principles: 1) the occurrence of fibrous antigorite in materials used to pave roads has been correlated with high mesothelioma rates in New Caledonia. Antigorite was also the cause of asbestosis in Poland, and in

  18. [Carcinogens exposure risk control: balance and strategies of action within the most emblematic industrial divisions].

    Science.gov (United States)

    Silvestri, Stefano

    2009-01-01

    In Italy during the last three decades important changes in employment have occurred. During the '70s, thanks to a variety of factors, the hygiene conditions of work have undergone a process of slow, but gradual improvement, which has not been arrested during the following decades. New legislation, partly deriving from European directives, has been introduced, and processes of outsourcing have moved the most burdensome and pollutants industrial productions to developing countries. Nevertheless, the estimates of the number of exposed (or even potentially so) workers, to carcinogens remain quite high. Currently, in absence of the planned National Information System on Prevention, it is impossible to estimate in how many and which workplaces primary prevention plans and facilities have been already installed. This paper aims to describe the situation related to most occupationally diffused carcinogenic agents: asbestos, wood and crystalline silica dusts, each one for its specificity. It also describes the innovations introduced by the most recent legislation, in particular with regard to the asbestos risk control. Finally, it stresses the need for a reform of the insurance premiums in order to introduce a mechanism for rewarding those employers who implement primary prevention facilities and penalizing those who don't. The economic advantages should gradually cover the cost of risk control technology.

  19. DNA repair studies in mouse germ cells exposed to two carcinogens and two non-carcinogens

    International Nuclear Information System (INIS)

    Sega, G.A.; Owens, J.G.

    1987-01-01

    An in vivo test was used to measure induced unscheduled DNA synthesis (UDS) in the germ cells of male mice exposed to the carcinogens benzo(a)pyrene [B(a)P] and 2-acetylaminofluorene (2AAF), and to the noncarcinogens pyrene (PYR) and 4-acetylaminofluorene (4AAF). Early spermatids, a DNA-repair competent stage, were used to test the effects of all chemicals. After chemical treatment and testicular injection of [ 3 H]dThd, sperm were recovered 16 days later from the caudal epididymides (these sperm were in early spermatid stages at the time of treatment) and assayed for the unscheduled incorporation of [ 3 H]dThd using liquid scintillation counting (LSC). Exposures of 2AAF ranged from 125 to 1600 mg/kg, 4AAF from 125 to 2000 mg/kg, PYR from 100 to 600 mg/kg, B(a)P from 100 to 400 mg/kg. Chemicals were administered both by intraperitoneal (i.p.) injection and by gavage. Methyl methanesulfonate (MMS) was used as a positive control

  20. 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

  1. Classification of carcinogenic and mutagenic properties using machine learning method

    DEFF Research Database (Denmark)

    Moorthy, N. S.Hari Narayana; Kumar, Surendra; Poongavanam, Vasanthanathan

    2017-01-01

    An accurate calculation of carcinogenicity of chemicals became a serious challenge for the health assessment authority around the globe because of not only increased cost for experiments but also various ethical issues exist using animal models. In this study, we provide machine learning...

  2. Chemical procedures to detect carcinogenic compound in domestic wastewater

    International Nuclear Information System (INIS)

    Abd Manan T S; Malakahmad A

    2013-01-01

    This review presents chemical methods to detect carcinogenic compound in wastewater. Atomic absorption spectroscopy (AAS), high performance liquid chromatography (HPLC) and gas chromatography mass spectroscopy (GCMS) and their alternative attached equipments were discussed. The application of each method is elaborated using related studies in the field.

  3. Mycotoxins as human carcinogens-the IARC Monographs classification.

    Science.gov (United States)

    Ostry, Vladimir; Malir, Frantisek; Toman, Jakub; Grosse, Yann

    2017-02-01

    Humans are constantly exposed to mycotoxins (e.g. aflatoxins, ochratoxins), mainly via food intake of plant and animal origin. The health risks stemming from mycotoxins may result from their toxicity, in particular their carcinogenicity. In order to prevent these risks, the International Agency for Research on Cancer (IARC) in Lyon (France)-through its IARC Monographs programme-has performed the carcinogenic hazard assessment of some mycotoxins in humans, on the basis of epidemiological data, studies of cancer in experimental animals and mechanistic studies. The present article summarizes the carcinogenic hazard assessments of those mycotoxins, especially aflatoxins (aflatoxin B 1 , B 2 , G 1 , G 2 and M 1 ), fumonisins (fumonisin B 1 and B 2 ) and ochratoxin A (OTA). New information regarding the genotoxicity of OTA (formation of OTA-DNA adducts), the role of OTA in oxidative stress and the identification of epigenetic factors involved in OTA carcinogenesis-should they indeed provide strong evidence that OTA carcinogenicity is mediated by a mechanism that also operates in humans-could lead to the reclassification of OTA.

  4. Carcinogenicity assessment of water-soluble nickel compounds.

    Science.gov (United States)

    Goodman, Julie E; Prueitt, Robyn L; Dodge, David G; Thakali, Sagar

    2009-01-01

    IARC is reassessing the human carcinogenicity of nickel compounds in 2009. To address the inconsistencies among results from studies of water-soluble nickel compounds, we conducted a weight-of-evidence analysis of the relevant epidemiological, toxicological, and carcinogenic mode-of-action data. We found the epidemiological evidence to be limited, in that some, but not all, data suggest that exposure to soluble nickel compounds leads to increased cancer risk in the presence of certain forms of insoluble nickel. Although there is no evidence that soluble nickel acts as a complete carcinogen in animals, there is limited evidence that suggests it may act as a tumor promoter. The mode-of-action data suggest that soluble nickel compounds will not be able to cause genotoxic effects in vivo because they cannot deliver sufficient nickel ions to nuclear sites of target cells. Although the mode-of-action data suggest several possible non-genotoxic effects of the nickel ion, it is unclear whether soluble nickel compounds can elicit these effects in vivo or whether these effects, if elicited, would result in tumor promotion. The mode-of-action data equally support soluble nickel as a promoter or as not being a causal factor in carcinogenesis at all. The weight of evidence does not indicate that soluble nickel compounds are complete carcinogens, and there is only limited evidence that they could act as tumor promoters.

  5. CARCINOGENIC EFFECTS OF LOW DOSES OF IONIZING RADIATION

    Science.gov (United States)

    Carcinogenic Effects of Low Doses of Ionizing RadiationR Julian Preston, Environmental Carcinogenesis Division, NHEERL, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711The form of the dose-response curve for radiation-induced cancers, particu...

  6. The precipitation synthesis of broad-spectrum UV absorber nanoceria

    International Nuclear Information System (INIS)

    Nurhasanah, Iis; Sutanto, Heri; Puspaningrum, Nurul Wahyu

    2013-01-01

    In this paper the possibility of nanoceria as broad-spectrum UV absorber was evaluated. Nanoceria were synthesized by precipitation process from cerium nitrate solution and ammonium hydroxide as precipitant agent. Isopropanol was mixed with water as solvent to prevent hard agglomeration. The structure of resulting nanoceria was characterized by x-ray diffractometer (XRD). The transparency in the visible light and efficiency of protection in UV A region were studied using ultraviolet-visible (UV - Vis) spectrophotometer. The results show that nanoceria possess good tranparency in visible light and high UV light absorption. The critical absorption wavelenght of 368 nm was obtained which is desirable for excellent broad-spectrum protection absorbers. Moreover, analysis of photodegradation nanoceria to methylene blue solution shows poor photocatalytic activity. It indicates that nanoceria suitable for used as UV absorber in personal care products

  7. Risk-based indicators of Canadians' exposures to environmental carcinogens.

    Science.gov (United States)

    Setton, Eleanor; Hystad, Perry; Poplawski, Karla; Cheasley, Roslyn; Cervantes-Larios, Alejandro; Keller, C Peter; Demers, Paul A

    2013-02-12

    Tools for estimating population exposures to environmental carcinogens are required to support evidence-based policies to reduce chronic exposures and associated cancers. Our objective was to develop indicators of population exposure to selected environmental carcinogens that can be easily updated over time, and allow comparisons and prioritization between different carcinogens and exposure pathways. We employed a risk assessment-based approach to produce screening-level estimates of lifetime excess cancer risk for selected substances listed as known carcinogens by the International Agency for Research on Cancer. Estimates of lifetime average daily intake were calculated using population characteristics combined with concentrations (circa 2006) in outdoor air, indoor air, dust, drinking water, and food and beverages from existing monitoring databases or comprehensive literature reviews. Intake estimates were then multiplied by cancer potency factors from Health Canada, the United States Environmental Protection Agency, and the California Office of Environmental Health Hazard Assessment to estimate lifetime excess cancer risks associated with each substance and exposure pathway. Lifetime excess cancer risks in excess of 1 per million people are identified as potential priorities for further attention. Based on data representing average conditions circa 2006, a total of 18 carcinogen-exposure pathways had potential lifetime excess cancer risks greater than 1 per million, based on varying data quality. Carcinogens with moderate to high data quality and lifetime excess cancer risk greater than 1 per million included benzene, 1,3-butadiene and radon in outdoor air; benzene and radon in indoor air; and arsenic and hexavalent chromium in drinking water. Important data gaps were identified for asbestos, hexavalent chromium and diesel exhaust in outdoor and indoor air, while little data were available to assess risk for substances in dust, food and beverages. The ability to

  8. Risk assessment of DNA-reactive carcinogens in food

    International Nuclear Information System (INIS)

    Jeffrey, A.M.; Williams, G.M.

    2005-01-01

    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 B 1 (AFB 1 ), a limit of 20 ppb or ∼30 μg/day has been set and is considered a tolerable daily intake (TDI). Since AFB 1 is considered a potent carcinogen, doses of 32 P-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

  9. USING PROTEOMICS TO MONITOR PROTEIN EXPRESSION IN HUMAN CELLS EXPOSED TO CARCINOGENS

    Science.gov (United States)

    People are continuously exposed exogenously to varying amounts of chemicals that have been shown to have carcinogenic properties in experimental systems. It has been estimated that exposure to environmental chemical carcinogens in the environment may contribute significantly to t...

  10. Carcinogen derived biomarkers: applications in studies of human exposure to secondhand tobacco smoke

    OpenAIRE

    Hecht, S

    2004-01-01

    Objective: To review the literature on carcinogen derived biomarkers of exposure to secondhand tobacco smoke (SHS). These biomarkers are specifically related to known carcinogens in tobacco smoke and include urinary metabolites, DNA adducts, and blood protein adducts.

  11. Impact of DNA repair on the dose-response of colorectal cancer formation induced by dietary carcinogens.

    Science.gov (United States)

    Fahrer, Jörg; Kaina, Bernd

    2017-08-01

    Colorectal cancer (CRC) is one of the most frequently diagnosed cancers, which is causally linked to dietary habits, notably the intake of processed and red meat. Processed and red meat contain dietary carcinogens, including heterocyclic aromatic amines (HCAs) and N-nitroso compounds (NOC). NOC are agents that induce various N-methylated DNA adducts and O 6 -methylguanine (O 6 -MeG), which are removed by base excision repair (BER) and O 6 -methylguanine-DNA methyltransferase (MGMT), respectively. HCAs such as the highly mutagenic 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) cause bulky DNA adducts, which are removed from DNA by nucleotide excision repair (NER). Both O 6 -MeG and HCA-induced DNA adducts are linked to the occurrence of KRAS and APC mutations in colorectal tumors of rodents and humans, thereby driving CRC initiation and progression. In this review, we focus on DNA repair pathways removing DNA lesions induced by NOC and HCA and assess their role in protecting against mutagenicity and carcinogenicity in the large intestine. We further discuss the impact of DNA repair on the dose-response relationship in colorectal carcinogenesis in view of recent studies, demonstrating the existence of 'no effect' point of departures (PoDs), i.e. thresholds for genotoxicity and carcinogenicity. The available data support the threshold concept for NOC with DNA repair being causally involved. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Different mechanisms of modulation of gap junction communication by non-genotoxic carcinogens in rat liver in vivo

    International Nuclear Information System (INIS)

    Cowles, C.; Mally, A.; Chipman, J.K.

    2007-01-01

    This is a comparative study of the mechanisms by which three different rodent non-genotoxic carcinogens modulate connexin-mediated gap junction intercellular communication in male rat liver in vivo. In the case of the peroxisome proliferating agent Wy-14,643, a non-hepatotoxic dose of 50 mg/kg led to a marked loss of inter-hepatocyte dye transfer associated with a loss of both Cx32 and Cx26 protein expression. In contrast, p,p'-dichlorodiphenyltrichloroethane (DDT) at a non-hepatotoxic dose (25 mg/kg) was not found to alter Cx32 or Cx26 expression or to produce a measurable Cx32 serine phosphorylation but did give a small, significant reduction of cell communication. Carbon tetrachloride (CCl 4 ) did not affect cell communication (despite a small significant reduction of Cx32 content) at a non-hepatotoxic dose. Both loss of communication and Cx32 expression was observed only at a dose that caused hepatocyte toxicity as evidenced by increased serum alanine aminotransferase activity. Overall, the findings emphasise that loss of gap junctional communication in vivo can contribute to carcinogenesis by non-genotoxic carcinogens through different primary mechanism. In contrast to Wy-14,643 and DDT, the results with CCl 4 are consistent with a requirement for hepatotoxicity in its carcinogenic action

  13. The effect of substituents in the aromatic ring on carcinogenicity of N-nitrosomethylaniline in F344 rats.

    Science.gov (United States)

    Kroeger-Koepke, M B; Reuber, M D; Iype, P T; Lijinsky, W; Michejda, C J

    1983-01-01

    N-Nitroso-N-methylaniline (NMA) and N-nitroso-N-methyl-4-fluoroaniline (p-F-NMA), both non-mutagenic in Salmonella typhimurium and N-nitroso-N-methyl-4-nitroaniline (p-NO2-NMA), a potent mutagen, were tested for carcinogenicity in F344 rats. NMA was shown to induce a high level of tumors in the upper gastrointestinal tract, particularly in the esophagus. Male rats treated with NMA died with tumors at a slightly higher rate than females, although the final tumor yield was the same. Most of the rats treated with p-F-NMA also developed tumors of the esophagus, but they died less rapidly than the NMA treated rats, indicating that p-F-NMA is a slightly weaker carcinogen than NMA. The powerful, directly acting mutagen, p-NO2-NMA did not appear to induce tumors at all since its tumor spectrum was essentially identical to that of the untreated control rats. Thus, the carcinogenic activities of NMA and its substituted analogs do not appear to correlate with bacterial mutagenesis assays. Additionally, NMA, p-F-NMA and N-nitroso-N-methyl-4-bromoaniline, the last a strong mutagen in S. typhimurium, were shown not to induce sister chromatid exchanges in CHO cells and in a clone of a CHO:liver cell hybrid which had previously been shown to be sensitive to chemical agents which require metabolic activation.

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

    International Nuclear Information System (INIS)

    Conolly, Rory B.; Gaylor, David W.; Lutz, Werner K.

    2005-01-01

    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

  15. Nutrition in adult and childhood cancer: role of carcinogens and anti-carcinogens.

    Science.gov (United States)

    Mosby, Terezie T; Cosgrove, Maeve; Sarkardei, Samiramis; Platt, Karl L; Kaina, Bernd

    2012-10-01

    There is no doubt that diet is one of the main modifiable risk factors for many degenerative diseases, including cancer. More than 30% of adult cancers can be prevented or delayed by diet, being physically active and having a healthy body weight. Plant-based foods, including fruit, vegetables, and whole grains, a favorable omega-6/omega-3 polyunsaturated fatty acids ratio, and fish consumption have a protective effect against cancer. On the contrary, a low intake of fruit and vegetables, high intake of red and processed meat, high intake of sodium, alcohol consumption, a diet rich in refined carbohydrates, and a high intake of total fat may increase risk of cancer. Furthermore, calorie restriction and having a body/mass index on the lower end of the normal range can significantly decrease or delay the onset of cancers. Most studies were performed on adults and thus the role of diet in childhood cancer is less well-understood. In the past, diet was not considered to play any role in its etiology in children. However, nowadays there is a growing body of evidence that prolonged and frequent breastfeeding, the maternal diet during pregnancy and vitamin intake during pregnancy, may impart benefit for reduced cancer risk in children. Usually, decades of healthy dietary habits are needed to see significant difference in cancer risk. Therefore, diet choices and diet preparation starting early in life deserve more attention. Here we review data focusing on which dietary factors, including food-borne carcinogens, affect the onset of cancers in adults and stress out the potential role of diet in childhood cancer prevention.

  16. Evaluation of carcinogenic potential of the herbicide glyphosate, drawing on tumor incidence data from fourteen chronic/carcinogenicity rodent studies.

    Science.gov (United States)

    Greim, Helmut; Saltmiras, David; Mostert, Volker; Strupp, Christian

    2015-03-01

    Abstract Glyphosate, an herbicidal derivative of the amino acid glycine, was introduced to agriculture in the 1970s. Glyphosate targets and blocks a plant metabolic pathway not found in animals, the shikimate pathway, required for the synthesis of aromatic amino acids in plants. After almost forty years of commercial use, and multiple regulatory approvals including toxicology evaluations, literature reviews, and numerous human health risk assessments, the clear and consistent conclusions are that glyphosate is of low toxicological concern, and no concerns exist with respect to glyphosate use and cancer in humans. This manuscript discusses the basis for these conclusions. Most toxicological studies informing regulatory evaluations are of commercial interest and are proprietary in nature. Given the widespread attention to this molecule, the authors gained access to carcinogenicity data submitted to regulatory agencies and present overviews of each study, followed by a weight of evidence evaluation of tumor incidence data. Fourteen carcinogenicity studies (nine rat and five mouse) are evaluated for their individual reliability, and select neoplasms are identified for further evaluation across the data base. The original tumor incidence data from study reports are presented in the online data supplement. There was no evidence of a carcinogenic effect related to glyphosate treatment. The lack of a plausible mechanism, along with published epidemiology studies, which fail to demonstrate clear, statistically significant, unbiased and non-confounded associations between glyphosate and cancer of any single etiology, and a compelling weight of evidence, support the conclusion that glyphosate does not present concern with respect to carcinogenic potential in humans.

  17. Transplacental carcinogenicity of inorganic arsenic in the drinking water: induction of hepatic, ovarian, pulmonary, and adrenal tumors in mice

    International Nuclear Information System (INIS)

    Waalkes, Michael P.; Ward, Jerrold M.; Liu Jie; Diwan, Bhalchandra A.

    2003-01-01

    Arsenic is a known human carcinogen, but development of rodent models of inorganic arsenic carcinogenesis has been problematic. Since gestation is often a period of high sensitivity to chemical carcinogenesis, we performed a transplacental carcinogenicity study in mice using inorganic arsenic. Groups (n=10) of pregnant C3H mice were given drinking water containing sodium arsenite (NaAsO 2 ) at 0 (control), 42.5, and 85 ppm arsenite ad libitum from day 8 to 18 of gestation. These doses were well tolerated and body weights of the dams during gestation and of the offspring subsequent to birth were not reduced. Dams were allowed to give birth, and offspring were weaned at 4 weeks and then put into separate gender-based groups (n=25) according to maternal exposure level. The offspring received no additional arsenic treatment. The study lasted 74 weeks in males and 90 weeks in females. A complete necropsy was performed on all mice and tissues were examined by light microscopy in a blind fashion. In male offspring, there was a marked increase in hepatocellular carcinoma incidence in a dose- related fashion (control, 12%; 42.5 ppm, 38%; 85 ppm, 61%) and in liver tumor multiplicity (tumors per liver; 5.6-fold over control at 85 ppm). In males, there was also a dose-related increase in adrenal tumor incidence and multiplicity. In female offspring, dose-related increases occurred in ovarian tumor incidence (control, 8%; 42.5 ppm, 26%; 85 ppm, 38%) and lung carcinoma incidence (control, 0%; 42.5 ppm, 4%; 85 ppm, 21%). Arsenic exposure also increased the incidence of proliferative lesions of the uterus and oviduct. These results demonstrate that oral inorganic arsenic exposure, as a single agent, can induce tumor formation in rodents and establishes inorganic arsenic as a complete transplacental carcinogen in mice. The development of this rodent model of inorganic arsenic carcinogenesis has important implications in defining the mechanism of action for this common environmental

  18. UV Deprivation Influences Social UV Preference in Juvenile Sticklebacks

    Directory of Open Access Journals (Sweden)

    Ricarda Modarressie

    2015-05-01

    Full Text Available Social aggregations occur in many different animal taxa and mainly result from non-random assortment. Investigating factors that shape and maintain the composition of social aggregations are among others a main topic for understanding ecological speciation processes. Aggregation decisions are mediated by olfactory and visual cues, which in many animals are extended into the UV part of the electromagnetic spectrum. Here, we were interested in developmental plasticity of social preferences with respect to UV radiation in aquatic organisms. Specifically, we tested whether different lighting environments with respect to UV wavelengths during early life stages influence the shoaling preference in juvenile threespine sticklebacks (Gasterosteus aculeatus. Family (full-sibling groups were split and reared under UV-lacking (UV- and UV-present (UV+ lighting conditions. Subsequent shoal choice experiments, in which test fish from both rearing conditions could simultaneously choose between a shoal seen behind a UV-blocking (UV- and a shoal seen behind a UV-transmitting (UV+ filter, revealed a significant effect of lighting condition during rearing on association preference. Test fish that had been deprived of UV spent significantly more time near the UV- shoal compared to the test fish reared under full-spectrum lighting conditions. The results are discussed with respect to plasticity of the visual system and environmental lighting conditions.

  19. UV spectroscopy. Ch. 16

    International Nuclear Information System (INIS)

    Stevens, Eugene S.

    1991-01-01

    The use of synchrotron radiation (SR) in the ultraviolet (UV) region by biophysics and biophysical chemists continues to increase as access improves and as awareness of its unique combination of properties grows. SR is continuously tunable, intense (even in the UV region), and pulsed. Pulse characteristics are comparable to those of picosecond lasers, but have the advantage of being independent of wavelength. Drawbacks are the continuous, but slow, decay of intensity arising from loss of particles in the ring, and the intrinsic limitation in pulse repetition rate. The particular combination of features that makes SR a superior light source depends upon the application. Spectroscopic techniques based on absorption and some techniques based on emission exploit its intensity and continuous tunability; time resolved techniques make use of its pulse characteristics. This chapter is a status report on two of the major biological applications of UV SR, circular dichroism and time-resolved fluorescence, covering mainly the published literature of the last five years. For the present purpose, the term UV is understood to include the vacuum ultraviolet region to 100 nm. (author). 83 refs.; 4 figs.; 6 tabs

  20. A Review of the Carcinogenic Potential of Bisphenol A

    Science.gov (United States)

    Seachrist, Darcie D; Bonk, Kristen W.; Ho, Shuk-Mei; Prins, Gail S.; Soto, Ana M.; Keri, Ruth A.

    2015-01-01

    The estrogenic properties of bisphenol A (BPA), a ubiquitous synthetic monomer that can leach into the food and water supply, have prompted considerable research into exposure-associated health risks in humans. Endocrine-disrupting properties of BPA suggest it may impact developmental plasticity during early life, predisposing individuals to disease at doses below the oral reference dose (RfD) established by the Environmental Protection Agency in 1982. Herein, we review the current in vivo literature evaluating the carcinogenic properties of BPA. We conclude that there is substantial evidence from rodent studies indicating that early-life BPA exposures below the RfD lead to increased susceptibility to mammary and prostate cancer. Based on the definitions of “carcinogen” put forth by the International Agency for Research on Cancer and the National Toxicology Program, we propose that BPA may be reasonably anticipated to be a human carcinogen in the breast and prostate due to its tumor promoting properties. PMID:26493093

  1. Retraction: Evaluation of Carcinogenic Effects of Electromagnetic Fields (Emf

    Directory of Open Access Journals (Sweden)

    Bakir Mehic

    2010-08-01

    Full Text Available This retracts the article "EVALUATION OF CARCINOGENIC EFFECTS OF ELECTROMAGNETIC FIELDS (EMF" on page 245. The Editor-in-chief of the Bosnian Journal ofBasic 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.

  2. Cytoprotective effect against UV-induced DNA damage and oxidative stress: role of new biological UV filter.

    Science.gov (United States)

    Said, T; Dutot, M; Martin, C; Beaudeux, J-L; Boucher, C; Enee, E; Baudouin, C; Warnet, J-M; Rat, P

    2007-03-01

    The majority of chemical solar filters are cytotoxic, particularly on sensitive ocular cells (corneal and conjunctival cells). Consequently, a non-cytotoxic UV filter would be interesting in dermatology, but more especially in ophthalmology. In fact, light damage to the eye can be avoided thanks to a very efficient ocular antioxidant system; indeed, the chromophores absorb light and dissipate its energy. After middle age, a decrease in the production of antioxidants and antioxidative enzymes appears with accumulation of endogenous molecules that are phototoxic. UV radiations can induce reactive oxygen species formation, leading to various ocular diseases. Because most UV filters are cytotoxic for the eye, we investigated the anti-UV properties of Calophyllum inophyllum oil in order to propose it as a potential vehicle, free of toxicity, with a natural UV filter action in ophthalmic formulation. Calophyllum inophyllum oil, even at low concentration (1/10,000, v/v), exhibited significant UV absorption properties (maximum at 300nm) and was associated with an important sun protection factor (18-22). Oil concentrations up to 1% were not cytotoxic on human conjunctival epithelial cells, and Calophyllum inophyllum oil appeared to act as a cytoprotective agent against oxidative stress and DNA damage (85% of the DNA damage induced by UV radiations were inhibited with 1% Calophyllum oil) and did not induce in vivo ocular irritation (Draize test on New Zealand rabbits). Calophyllum inophyllum oil thus exhibited antioxidant and cytoprotective properties, and therefore might serve, for the first time, as a natural UV filter in ophthalmic preparations.

  3. Systematic network assessment of the carcinogenic activities of cadmium

    International Nuclear Information System (INIS)

    Chen, Peizhan; Duan, Xiaohua; Li, Mian; Huang, Chao; Li, Jingquan; Chu, Ruiai; Ying, Hao; Song, Haiyun; Jia, Xudong; Ba, Qian; Wang, Hui

    2016-01-01

    Cadmium has been defined as type I carcinogen for humans, but the underlying mechanisms of its carcinogenic activity and its influence on protein-protein interactions in cells are not fully elucidated. The aim of the current study was to evaluate, systematically, the carcinogenic activity of cadmium with systems biology approaches. From a literature search of 209 studies that performed with cellular models, 208 proteins influenced by cadmium exposure were identified. All of these were assessed by Western blotting and were recognized as key nodes in network analyses. The protein-protein functional interaction networks were constructed with NetBox software and visualized with Cytoscape software. These cadmium-rewired genes were used to construct a scale-free, highly connected biological protein interaction network with 850 nodes and 8770 edges. Of the network, nine key modules were identified and 60 key signaling pathways, including the estrogen, RAS, PI3K-Akt, NF-κB, HIF-1α, Jak-STAT, and TGF-β signaling pathways, were significantly enriched. With breast cancer, colorectal and prostate cancer cellular models, we validated the key node genes in the network that had been previously reported or inferred form the network by Western blotting methods, including STAT3, JNK, p38, SMAD2/3, P65, AKT1, and HIF-1α. These results suggested the established network was robust and provided a systematic view of the carcinogenic activities of cadmium in human. - Highlights: • A cadmium-influenced network with 850 nodes and 8770 edges was established. • The cadmium-rewired gene network was scale-free and highly connected. • Nine modules were identified, and 60 key signaling pathways related to cadmium-induced carcinogenesis were found. • Key mediators in the network were validated in multiple cellular models.

  4. Mammalian cell transformation: Mechanisms of carcinogenesis and assays for carcinogens

    International Nuclear Information System (INIS)

    Barrett, J.C.; Tennant, R.W.

    1985-01-01

    This book contains nine sections, each consisting of several papers. The section titles are: Molecular Changes in Cell Transformation; Differentiation, Growth Control, and Cell Transformation; Mutagenesis and Cell Transformation; Tumor Promotion and Cell Transformation; Mechanisms of Transformation of Human Fibroblasts; Mechanisms of Transformation of Epithelial Cells; Mechanisms of C 3 H 10T12 Cell Transformation; Mechanisms of Radiation-Induced Cell Transformation; and Use of Cell Transformation Assays for Carcinogen Testing

  5. Risk assessment of nickel carcinogenicity and occupational lung cancer.

    OpenAIRE

    Shen, H M; Zhang, Q F

    1994-01-01

    Recent progress in risk assessment of nickel carcinogenicity and its correlation with occupational lung cancer in nickel-exposed workers is reviewed. Epidemiological investigations provide reliable data indicating the close relation between nickel exposure and high lung cancer risk, especially in nickel refineries. The nickel species-specific effects and the dose-response relationship between nickel exposure and lung cancer are among the main questions that are explored extensively. It is als...

  6. Carcinogenic activity of polycyclic hydrocarbons on man and animals

    Energy Technology Data Exchange (ETDEWEB)

    Shabad, L M

    1976-03-01

    Basic facts are reported on the carcinogenic activity of polycyclic aromatic hydrocarbons (PAH) towards humans and animals. Benzyprene (BP) is taken as a standard indicator for PAH. Studies of the distribution of BP in atmosphere, hydrosphere, in soil, in plants, and in animals led to an understanding of the accumulation and breakdown of this chemical. On this basis, safety limits were set as a prophylactic measure.

  7. Systematic network assessment of the carcinogenic activities of cadmium

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Peizhan; Duan, Xiaohua; Li, Mian; Huang, Chao [Key Laboratory of Food Safety Research, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai (China); Li, Jingquan; Chu, Ruiai; Ying, Hao; Song, Haiyun [Key Laboratory of Food Safety Research, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai (China); Key Laboratory of Food Safety Risk Assessment, Ministry of Health, Beijing (China); Jia, Xudong [Key Laboratory of Food Safety Risk Assessment, Ministry of Health, Beijing (China); Ba, Qian, E-mail: qba@sibs.ac.cn [Key Laboratory of Food Safety Research, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai (China); Key Laboratory of Food Safety Risk Assessment, Ministry of Health, Beijing (China); Wang, Hui, E-mail: huiwang@sibs.ac.cn [Key Laboratory of Food Safety Research, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai (China); Key Laboratory of Food Safety Risk Assessment, Ministry of Health, Beijing (China); School of Life Science and Technology, ShanghaiTech University, Shanghai (China)

    2016-11-01

    Cadmium has been defined as type I carcinogen for humans, but the underlying mechanisms of its carcinogenic activity and its influence on protein-protein interactions in cells are not fully elucidated. The aim of the current study was to evaluate, systematically, the carcinogenic activity of cadmium with systems biology approaches. From a literature search of 209 studies that performed with cellular models, 208 proteins influenced by cadmium exposure were identified. All of these were assessed by Western blotting and were recognized as key nodes in network analyses. The protein-protein functional interaction networks were constructed with NetBox software and visualized with Cytoscape software. These cadmium-rewired genes were used to construct a scale-free, highly connected biological protein interaction network with 850 nodes and 8770 edges. Of the network, nine key modules were identified and 60 key signaling pathways, including the estrogen, RAS, PI3K-Akt, NF-κB, HIF-1α, Jak-STAT, and TGF-β signaling pathways, were significantly enriched. With breast cancer, colorectal and prostate cancer cellular models, we validated the key node genes in the network that had been previously reported or inferred form the network by Western blotting methods, including STAT3, JNK, p38, SMAD2/3, P65, AKT1, and HIF-1α. These results suggested the established network was robust and provided a systematic view of the carcinogenic activities of cadmium in human. - Highlights: • A cadmium-influenced network with 850 nodes and 8770 edges was established. • The cadmium-rewired gene network was scale-free and highly connected. • Nine modules were identified, and 60 key signaling pathways related to cadmium-induced carcinogenesis were found. • Key mediators in the network were validated in multiple cellular models.

  8. DNA repair synthesis in rat retinal ganglion cells treated with chemical carcinogens or ultraviolet light in vitro, with special reference to aging and repair level

    International Nuclear Information System (INIS)

    Ishikawa, T.; Takayama, S.; Kitagawa, T.

    1978-01-01

    A system in which the retinal tissues of noninbred Wistar rats were used in combination with autoradiography was developed for measurement of DNA repair synthesis in ganglion cells of the central nervous system. Retinal tissues in short-term organ culture were treated with various carcinogens plus tritiated thymidine ([methyl -3 H]dThd) or were irradiated with uv light and then treated with [methyl -3 H]dThd. Preliminary study with retinal tissues from rats at various ages revealed no age-associated changes in the levels of unscheduled DNA synthesis in ganglion cells

  9. [Alkylating agents].

    Science.gov (United States)

    Pourquier, Philippe

    2011-11-01

    With the approval of mechlorethamine by the FDA in 1949 for the treatment of hematologic malignancies, alkylating agents are the oldest class of anticancer agents. Even though their clinical use is far beyond the use of new targeted therapies, they still occupy a major place in specific indications and sometimes represent the unique option for the treatment of refractory diseases. Here, we are reviewing the major classes of alkylating agents and their mechanism of action, with a particular emphasis for the new generations of alkylating agents. As for most of the chemotherapeutic agents used in the clinic, these compounds are derived from natural sources. With a complex but original mechanism of action, they represent new interesting alternatives for the clinicians, especially for tumors that are resistant to conventional DNA damaging agents. We also briefly describe the different strategies that have been or are currently developed to potentiate the use of classical alkylating agents, especially the inhibition of pathways that are involved in the repair of DNA lesions induced by these agents. In this line, the development of PARP inhibitors is a striking example of the recent regain of interest towards the "old" alkylating agents.

  10. Standardization of UV LED measurements

    Science.gov (United States)

    Eppeldauer, G. P.; Larason, T. C.; Yoon, H. W.

    2015-09-01

    Traditionally used source spectral-distribution or detector spectral-response based standards cannot be applied for accurate UV LED measurements. Since the CIE standardized rectangular-shape spectral response function for UV measurements cannot be realized with small spectral mismatch when using filtered detectors, the UV measurement errors can be several times ten percent or larger. The UV LEDs produce broadband radiation and both their peaks or spectral bandwidths can change significantly. The detectors used for the measurement of these LEDs also have different spectral bandwidths. In the discussed example, where LEDs with 365 nm peak are applied for fluorescent crack-recognition using liquid penetrant (non-destructive) inspection, the broadband radiometric LED (signal) measurement procedure is standardized. A UV LED irradiance-source was calibrated against an FEL lamp standard to determine its spectral irradiance. The spectral irradiance responsivity of a reference UV meter was also calibrated. The output signal of the reference UV meter was calculated from the spectral irradiance of the UV source and the spectral irradiance responsivity of the reference UV meter. From the output signal, both the integrated irradiance (in the reference plane of the reference meter) and the integrated responsivity of the reference meter were determined. Test UV meters calibrated for integrated responsivity against the reference UV meter, can be used to determine the integrated irradiance from a field UV source. The obtained 5 % (k=2) measurement uncertainty can be decreased when meters with spectral response close to a constant value are selected.

  11. Health hazards of UV radiation

    International Nuclear Information System (INIS)

    Matthes, R.

    1994-01-01

    The author describes the effects and health risks of UV exposure. This includes UV effects on the DNS, the eyes, the immune system, and the skin. Finally, recommendations are given for protection against excessive UV exposure on the basis of the IRPA/INIRC guidelines. (orig.) [de

  12. Transverse effects in UV FELs

    International Nuclear Information System (INIS)

    Small, D.W.; Wong, R.K.; Colson, W.B.

    1995-01-01

    In an ultraviolet Free Electron Laser (UV FEL), the electron beam size can be approximately the same as the optical mode size. The performance of a UV FEL is studied including the effect of emittance, betatron focusing, and external focusing of the electron beam on the transverse optical mode. The results are applied to the Industrial Laser Consortium's UV FEL

  13. Chemical and UV Mutagenesis.

    Science.gov (United States)

    Bose, Jeffrey L

    2016-01-01

    The ability to create mutations is an important step towards understanding bacterial physiology and virulence. While targeted approaches are invaluable, the ability to produce genome-wide random mutations can lead to crucial discoveries. Transposon mutagenesis is a useful approach, but many interesting mutations can be missed by these insertions that interrupt coding and noncoding sequences due to the integration of an entire transposon. Chemical mutagenesis and UV-based random mutagenesis are alternate approaches to isolate mutations of interest with the potential of only single nucleotide changes. Once a standard method, difficulty in identifying mutation sites had decreased the popularity of this technique. However, thanks to the recent emergence of economical whole-genome sequencing, this approach to making mutations can once again become a viable option. Therefore, this chapter provides an overview protocol for random mutagenesis using UV light or DNA-damaging chemicals.

  14. UV curable materials development

    Energy Technology Data Exchange (ETDEWEB)

    Parker, B.G.

    1996-12-01

    Adhesives, coatings, and inks were selected for evaluation based on literature search and possible production applications. A differential photocalorimeter was used to measure degree of cure and allow prediction of optimum processing conditions. UV cure equipment were characterized and the ability to size equipment to specific materials cure needs established. Adhesion tests procedures were developed for the adhesives and solvent resistance testing procedures developed for the coatings and inks.

  15. Varied exposure to carcinogenic, mutagenic, and reprotoxic (CMR) chemicals in occupational settings in France

    Energy Technology Data Exchange (ETDEWEB)

    Havet, Nathalie [Univ. Claude Bernard Lyon 1 (France). Lab. SAF; Penot, Alexis [Lyon Univ. (France). ENS Lyon, GATE-UMR 5824-CNRS; Morelle, Magali; Perrier, Lionel [Lyon Univ. (France). Direction de la Recherche Clinique et de l' Innovation; Charbotel, Barbara [Univ. Claude Bernard Lyon 1 (France). Centre Hospitalier Lyon Sud Service des Maladies Professionnelles; Fervers, Beatrice [Lyon Univ. (France). Dept. Cancer and Environment

    2017-02-15

    To explore varied exposure to carcinogenic, mutagenic, and reprotoxic chemicals (CMR) for French employees. Our study assessed data from the French national cross-sectional survey of occupational risks (SUMER) that was conducted in 2010 in a national representative sample of employees. We selected 28 CMR agents that were classified by the International Agency for Research on Cancer or European Union as being known or presumed to have CMR potential in humans. The association of individual and job characteristics with exposure prevalence, duration, and intensity of the CMR agents during a 1-week period was examined using multilevel logistic regression analysis. Overall, 10.4% of employees in 2010 were exposed to one or more CMR agents at their workplace, and 3.4% were subjected to multiple CMR exposures. Blue-collar workers, night-shift workers and workers with short-term employment contracts experienced higher exposure prevalence (p < 0.01) and intensity (p < 0.05). Bluecollar workers and shift workers experienced also longer exposure duration (p < 0.001). Conversely, managers, workers of large companies, and women were less exposed to CMR agents (p < 0.001). The presence of a Committee for Health, Safety, and Working Conditions, and intervention by Occupational Health and Safety officers were significantly associated with reduced exposure intensities (p < 0.001 and p < 0.05). Establishment of European CMR regulations and the existence of an applicable substitution principle reduced the exposure duration (p < 0.001) and intensity (p < 0.05). Our results point out disparities in CMR exposure and identify high-priority targets for prevention measures to help reducing social health discrepancies.

  16. Varied exposure to carcinogenic, mutagenic, and reprotoxic (CMR) chemicals in occupational settings in France

    International Nuclear Information System (INIS)

    Havet, Nathalie; Penot, Alexis; Morelle, Magali; Perrier, Lionel; Charbotel, Barbara; Fervers, Beatrice

    2017-01-01

    To explore varied exposure to carcinogenic, mutagenic, and reprotoxic chemicals (CMR) for French employees. Our study assessed data from the French national cross-sectional survey of occupational risks (SUMER) that was conducted in 2010 in a national representative sample of employees. We selected 28 CMR agents that were classified by the International Agency for Research on Cancer or European Union as being known or presumed to have CMR potential in humans. The association of individual and job characteristics with exposure prevalence, duration, and intensity of the CMR agents during a 1-week period was examined using multilevel logistic regression analysis. Overall, 10.4% of employees in 2010 were exposed to one or more CMR agents at their workplace, and 3.4% were subjected to multiple CMR exposures. Blue-collar workers, night-shift workers and workers with short-term employment contracts experienced higher exposure prevalence (p < 0.01) and intensity (p < 0.05). Bluecollar workers and shift workers experienced also longer exposure duration (p < 0.001). Conversely, managers, workers of large companies, and women were less exposed to CMR agents (p < 0.001). The presence of a Committee for Health, Safety, and Working Conditions, and intervention by Occupational Health and Safety officers were significantly associated with reduced exposure intensities (p < 0.001 and p < 0.05). Establishment of European CMR regulations and the existence of an applicable substitution principle reduced the exposure duration (p < 0.001) and intensity (p < 0.05). Our results point out disparities in CMR exposure and identify high-priority targets for prevention measures to help reducing social health discrepancies.

  17. Plasma-assisted cleaning of extreme UV optics

    NARCIS (Netherlands)

    Dolgov, Alexandr Alexeevich

    2018-01-01

    Plasma-assisted cleaning of extreme UV optics EUV-induced surface plasma chemistry of photo-active agents The next generation of photolithography, extreme ultraviolet (EUV) lithography, makes use of 13.5 nm radiation. The ionizing photon flux, and vacuum requirements create a challenging operating

  18. The inhibition of repair in UV irradiated human cells

    International Nuclear Information System (INIS)

    Collins, A.R.S.; Schor, S.L.; Johnson, R.T.

    1977-01-01

    Three different assay procedures are used to determine the effects of hydroxyurea on excision repair in UV-irradiated HeLa cells. At the cytological level, incubation of UV-irradiated metaphase cells with hydroxyurea caused chromosome decondensation. Using a modified alkaline sucrose gradient sedimentation technique involving minimal lysis before centrifugation, a marked retardation was found in the sedimentation of DNA from UV-irradiated cells incubated for a short period with hydroxyurea. The effect of hydroxyurea on the incorporation of [ 3 H]thymidine by UV-irradiated G1 cells was found to depend on the concentration of thymidine present in the medium. The results point to an inhibition of repair DNA synthesis by hydroxyurea (or deoxyadenosine), at the level of the supply of DNA precursors, i.e. in the same way that these agents inhibit semiconservative DNA synthesis. In the presence of these inhibitors, single-strand gaps accumulate in the DNA

  19. Innovative agents in cancer prevention.

    Science.gov (United States)

    Manson, Margaret M; Farmer, Peter B; Gescher, Andreas; Steward, William P

    2005-01-01

    There are many facets to cancer prevention: a good diet, weight control and physical activity, a healthy environment, avoidance of carcinogens such as those in tobacco smoke, and screening of populations at risk to allow early detection. But there is also the possibility of using drugs or naturally occurring compounds to prevent initiation of, or to suppress, tumour growth. Only a few such agents have been used to date in the clinic with any success, and these include non-steroidal anti-inflammatory drugs for colon, finasteride for prostate and tamoxifen or raloxifene for breast tumours. An ideal chemopreventive agent would restore normal growth control to a preneoplastic or cancerous cell population by modifying aberrant signalling pathways or inducing apoptosis (or both) in cells beyond repair. Characteristics for such an agent include selectivity for damaged or transformed cells, good bioavailability and more than one mechanism of action to foil redundancy or crosstalk in signalling pathways. As more research effort is being targeted towards this area, the distinction between chemotherapeutic and chemopreventive agents is blurring. Chemotherapeutic drugs are now being designed to target over- or under-active signalling molecules within cancer cells, a philosophy which is just as relevant in chemoprevention. Development of dietary agents is particularly attractive because of our long-standing exposure to them, their relative lack of toxicity, and encouraging indications from epidemiology. The carcinogenic process relies on the cell's ability to proliferate abnormally, evade apoptosis, induce angiogenesis and metastasise to distant sites. In vitro studies with a number of different diet-derived compounds suggest that there are molecules capable of modulating each of these aspects of tumour growth. However, on the negative side many of them have rather poor bioavailability. The challenge is to uncover their multiple mechanisms of action in order to predict their

  20. 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)

  1. 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)

  2. Experimental photoimmunology: immunologic ramifications of UV-induced carcinogenesis

    International Nuclear Information System (INIS)

    Daynes, R.A.; Bernhard, E.J.; Gurish, M.F.; Lynch, D.H.

    1981-01-01

    The use of animal model systems to investigate the sequence of events which lead to the induction and progression of skin tumors following chronic ultraviolet light (UVL) exposure has clearly shown that the direct mutagenic effects of UVL is only one of the components involved in this process. In spite of the fact that overt carcinogenesis is only one of the many effects produced by UV light, most hypotheses as to the mechanism by which UVL can cause the mutations necessary to achieve the transformed phenotype have focused on the direct effects of UVL on DNA and the generation of carcinogenic compounds. Investigations during the last 5 yr, however, have clearly demonstrated that immunologic factors are also critically important in the pathogenesis of UV-induced skin cancers. A complete understanding of UV-carcinogenesis must therefore consider the mechanisms which allow the transformed cell to evade immunologic rejection by the host in addition to those aspects which deal with conversion of a normal cell to a cancer cell. It is the object of this review to provide both a historical account of the work which established the immunologic consequences of chronic UVL exposure and the results of recent experiments designed to investigate the kinetics and mechanisms by which UVL affects the immunologic apparatus. In addition, a hypothetical model is presented to explain the sequence of events which ultimately lead to the emergence of the suppressor T-cells which regulate antitumor immune responses

  3. 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)

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

    1986-01-01

    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

  4. Protection policies for ionizing and UV radiation

    International Nuclear Information System (INIS)

    Bosnjakovic, B.F.M.

    1987-01-01

    Although ultraviolet radiation is generally considered as being part of non-ionizing radiation, the existing similarities with ionizing radiation are too striking to be overseen. A comparison of these two agents is becoming important in view of the increasing awareness of various environmental and health risks and the tendency to develop more uniform risk management policies with respect to the different physical and chemical agents. This paper explores the similarities and differences of UV and ionizing radiation from the point of view of policies either adopted or in development. Policy determinants include, among others, the following factors: biological effects, dosimetric quantities, relative contribution to exposure from different sources, hazard potential of different sources, quantification of detrimental consequences, public perception of the radiation hazards and regulation developments. These factors are discussed

  5. Different action of MMS and EMS in UV-sensitive strains of Aspergillus nidulans.

    Science.gov (United States)

    Babudri, N; Politi, M G

    1989-05-01

    The repair of methyl methanesulfonate (MMS) and ethyl methanesulfonate (EMS) damages has been investigated in the fungus Aspergillus nidulans. 4 UV-sensitive mutants, namely uvsB, uvsD, uvsF and uvsH have been tested for their sensitivity and mutability to the above-mentioned agents. The results obtained show that: (1) uvsB and uvsD mutants are no more sensitive than the wild-type strain to the lethal action of EMS. In contrast, they are more sensitive to MMS; (2) uvsF and uvsH mutants are more sensitive than the wild type to EMS at 37 degrees C but not at 20 degrees C. However, they are more sensitive than the wild type to MMS at 37 degrees C as well as at 20 degrees C; (3) the mutation frequencies after treatment with either MMS or EMS plotted against survival are not altered in the UV-sensitive strains compared to the wild-type strain. From these data it may be concluded that the repair of lethal lesions induced by ethylating and methylating agents is under the control of different pathways. Furthermore the mutants tested are not involved in the mutagenic process.

  6. Evaluation of the carcinogenic risks at the influence of POPs.

    Science.gov (United States)

    Nazhmetdinova, Aiman; Kassymbayev, Adlet; Chalginbayeva, Altinay

    2017-12-20

    Kazakhstan is included in the list of environmentally vulnerable countries and Kyzylorda oblast in particular. This is due to its geographical, spatial and temporal and socioeconomic features. As part of the program "Integrated approaches in the management of public health in the Aral region", we have carried out an expertise on many samples of natural environments and products. Samples were selected in accordance with sampling procedures according to regulatory documents by specialists of the Pesticide Toxicology Laboratory. It is accredited by the State Standard of the Republic of Kazakhstan, for compliance with ST RK ISO/IEC 17025-2007 "General requirements for the competence of test and calibration laboratories". Gas chromatograph was used for the determination of residues of organochlorine pesticides. For the determination of dioxins, polychlorinated biphenyl was conducted on the gas chromatomass spectrometer with quadruple detector produce by Agilent Company, USA. To assess the risk, we carried out the mathematical calculations according to the risk of chemicals polluting (No P 2.1.10.1920-04, Russia). Calculation of the carcinogenic risk was carried out with the use of data on the size of the exposure and meanings of carcinogenic potential factors (slope factor and unit risk). The evaluation of persistent organic pollutants (POPs), based on the previous results of the research concerning water, soil and food products, was held in five population settlements in Kyzylorda oblast villages: Ayteke bi, Zhalagash, Zhosaly, Shieli and Aralsk town. Pollution with the POPs in the environmental objects by means of exposition and evaluation of the carcinogenic risk to human health is confirmed by the data of the statistical reporting about some morbidity in Kyzylorda oblast, such as skin diseases and subcutaneous tissue, endocrine system diseases, pregnancy complications etc. The received levels of carcinogenic risks, which were first carried out in the Republic of

  7. Keishibukuryogan is not carcinogenic in Sprague-Dawley rats

    OpenAIRE

    Kanitani, Masanao; Nishimura, Nobuo; Edamoto, Hiroshi; Kase, Yoshio

    2016-01-01

    Keishibukuryogan is a traditional Japanese medicine widely administered to patients with menopausal symptoms. Because humans use it on a long-term basis, we believed that a carcinogenicity study was warranted. We orally administered keishibukuryogan (TJ-25) extract powder to 6-week-old Sprague-Dawley rats [Crl:CD(SD)], which were divided into four dosage groups-0 (water for injection), 100, 500 and 2,500 mg/kg/day for 24 months. We found that TJ-25 did not affect the survival rate of either s...

  8. Carcinogenic Substances Naturrally Occuring in the Human Diet

    Directory of Open Access Journals (Sweden)

    Mogos Viorel T.

    2018-03-01

    Full Text Available Oncogenesis is a result of the combined action of numerous factors peculiar to the body and the environment (the latter are more effective. Among dietary factors directly implied in the occurrence of malignant tumors we can mention: food additives, contaminated food, polycyclic aromatic hydrocarbons, nitrosamines and some components which are naturally present in food. Moreover, food-related malignancies are a consequence of the increased consumption of fats, proteins, alcohol in parallel with decreases in the consumption of dietary fibers and some micronutrients. Carcinogenic substances naturally present in food are of a particular interest for both nutritionist’s and patient’s, usually not being perceived as being harmful.

  9. Chemical Agents

    Science.gov (United States)

    ... CR) see Riot Control Agents Digitalis Distilled mustard (HD) see Sulfur mustard E Ethylene glycol F Fentanyls and other opioids H Hydrazine Hydrofluoric acid (hydrogen fluoride) Hydrogen chloride Hydrogen cyanide (AC) Hydrogen ...

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

    International Nuclear Information System (INIS)

    Mendelsohn, M.L.; Bakale, G.; McCreary, R.D.

    1989-01-01

    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

  11. Prevalence of occupational exposure to carcinogens among workers of Arabic, Chinese and Vietnamese ancestry in Australia.

    Science.gov (United States)

    Boyle, Terry; Carey, Renee N; Glass, Deborah C; Peters, Susan; Fritschi, Lin; Reid, Alison

    2015-09-01

    Although job-related diseases result in more deaths per year than job-related injuries, most research concerning ethnic minority workers has concerned accidents and injuries rather than disease-causing exposures such as carcinogens. We conducted a telephone-based cross-sectional survey to estimate the prevalence of occupational exposure to carcinogens among a sample of ethnic minority workers in Australia, and compared their exposure prevalence to that of a sample of the general Australian-born working population ('Australian workers'). One-third of the ethnic minority workers were exposed to at least one carcinogen at work. The likelihood of exposure to carcinogens was not significantly different from that of Australian workers, although the likelihood of exposure to individual carcinogens varied by ethnicity. Knowing the prevalence of exposure to carcinogens in the workplace in different ethnic groups will allow better targeted and informed occupational health and safety measures to be implemented where necessary. © 2015 Wiley Periodicals, Inc.

  12. 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.

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

    International Nuclear Information System (INIS)

    Tubiana, M.

    2009-01-01

    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

  14. Induction and repair of lethal and oncogenic lesions and their relationship to cytogenetic changes in UV-irradiated mouse 10T1/2 cells

    International Nuclear Information System (INIS)

    Chan, G.L.; Nagasawa, H.; Little, J.B.

    1979-01-01

    While bacterial system is valuable for the pragmatic purpose of screening potential environmental carcinogens, the fundamental difference between prokaryotes and mammalian cells warrant caution against the use of bacterial mutagenic mechanisms to explain the oncogenic process in mammalian cells. The 10 T1/2 cells exposed to UV light in the plateau phase and subcultured immediately to low density to assay for clonogenic survival were extremely resistant to the cytotoxic effect of UV light. Purely physical considerations such as the increased thickness of plateau phase cells and the increased cytoplasmic shielding of UV light from the nuclei were insufficient to account for this unusual resistance. The effect of caffeine on the repair processes in UV-irradiated mammalian cells appears to be exerted during the first DNA synthetic phase after the UV exposure. The daughter DNA synthesized on a UV-irradiated template is of reduced molecular weight. 10 T1/2 cells were exposed in the log phase of growth to UV light, and then they were cultured for the next 48 hours in the complete growth medium containing the specific concentration of caffeine. Parallel experiments were performed, in which cells were exposed for 48 hours to caffeine only with no prior exposure to UV light. It was found that caffeine did not potentiate the transformation by UV light. Caffeine alone induced sister chromatid exchange (SCE), whereas the caffeine given after UV light had no effect. The class of UV-induced lesions which induce SCE also leads to malignant transformation. (Yamashita, S.)

  15. Mode of carcinogenic action of pesticides inducing thyroid follicular cell tumors in rodents.

    OpenAIRE

    Hurley, P M

    1998-01-01

    Of 240 pesticides screened for carcinogenicity by the U.S. Environmental Protection Agency Office of Pesticide Programs, at least 24 (10%) produce thyroid follicular cell tumors in rodents. Thirteen of the thyroid carcinogens also induce liver tumors, mainly in mice, and 9 chemicals produce tumors at other sites. Some mutagenic data are available on all 24 pesticides producing thyroid tumors. Mutagenicity does not seem to be a major determinant in thyroid carcinogenicity, except for possibly ...

  16. CUVE - Cubesat UV Experiment: Unveil Venus' UV Absorber with Cubesat UV Mapping Spectrometer

    Science.gov (United States)

    Cottini, V.; Aslam, S.; D'Aversa, E.; Glaze, L.; Gorius, N.; Hewagama, T.; Ignatiev, N.; Piccioni, G.

    2017-09-01

    Our Venus mission concept Cubesat UV Experiment (CUVE) is one of ten proposals selected for funding by the NASA PSDS3 Program - Planetary Science Deep Space SmallSat Studies. CUVE concept is to insert a CubeSat spacecraft into a Venusian orbit and perform remote sensing of the UV spectral region using a high spectral resolution point spectrometer to resolve UV molecular bands, observe nightglow, and characterize the unidentified main UV absorber. The UV spectrometer is complemented by an imaging UV camera with multiple bands in the UV absorber main band range for contextual imaging. CUVE Science Objectives are: the nature of the "Unknown" UV-absorber; the abundances and distributions of SO2 and SO at and above Venus's cloud tops and their correlation with the UV absorber; the atmospheric dynamics at the cloud tops, structure of upper clouds and wind measurements from cloud-tracking; the nightglow emissions: NO, CO, O2. This mission will therefore be an excellent platform to study Venus' cloud top atmospheric properties where the UV absorption drives the planet's energy balance. CUVE would complement past, current and future Venus missions with conventional spacecraft, and address critical science questions cost effectively.

  17. Evidence supporting product standards for carcinogens in smokeless tobacco products.

    Science.gov (United States)

    Hatsukami, Dorothy K; Stepanov, Irina; Severson, Herb; Jensen, Joni A; Lindgren, Bruce R; Horn, Kimberly; Khariwala, Samir S; Martin, Julia; Carmella, Steven G; Murphy, Sharon E; Hecht, Stephen S

    2015-01-01

    Smokeless tobacco products sold in the United States vary significantly in yields of nicotine and tobacco-specific nitrosamines (TSNA). With the passage of the Family Smoking Prevention and Tobacco Control Act, the Food and Drug Administration now has the authority to establish product standards. However, limited data exist determining the relative roles of pattern of smokeless tobacco use versus constituent levels in the smokeless tobacco product in exposure of users to carcinogens. In this study, smokeless tobacco users of brands varying in nicotine and TSNA content were recruited from three different regions in the U.S. Participants underwent two assessment sessions. During these sessions, demographic and smokeless tobacco use history information along with urine samples to assess biomarkers of exposure and effect were collected. During the time between data collection, smokeless tobacco users recorded the amount and duration of smokeless tobacco use on a daily basis using their diary cards. Results showed that independent of pattern of smokeless tobacco use and nicotine yields, levels of TSNA in smokeless tobacco products played a significant role in carcinogen exposure levels. Product standards for reducing levels of TSNA in smokeless tobacco products are necessary to decrease exposure to these toxicants and potentially to reduce risk for cancer. ©2014 American Association for Cancer Research.

  18. Polyamines modulate carcinogen-induced mutagenesis in vivo.

    Science.gov (United States)

    Wallon, U Margaretha; O'Brien, Thomas G

    2005-01-01

    Elevated polyamine levels as a consequence of targeted overexpression of ornithine decarboxylase (ODC) to murine skin enhance susceptibility to tumorigenesis in this tissue. A possible mechanism for the enhanced susceptibility phenotype is an increased sensitivity of tissues with elevated polyamine levels to the mutagenic action of carcinogens. To test this hypothesis, a transgenic mouse model containing the Big Blue transgene and also expressing a K6/ODC transgene was developed. Incorporation of the K6/ODC transgene into the Big Blue model did not affect the spontaneous lacI mutant frequency in either skin or epidermis of the double-transgenic mice. After skin treatment with single doses of either 7,12-dimethylbenz[a]anthracene or N-methyl-N'-nitro-N-nitrosoguanidine, however, the mutant frequency was significantly increased in the skin of double-transgenic Big Blue;K6/ODC mice compared to Big Blue controls. The increases in mutant frequency were clearly due to ODC transgene activity, since treatment of mice with the ODC inhibitor, alpha-difluoromethylornithine, completely abolished the difference in mutant frequencies between double-transgenic and Big Blue mice. These results demonstrate that intracellular polyamine levels modulate mutation induction following carcinogen exposure. 2004 Wiley-Liss, Inc.

  19. Carcinogen specific dosimetry model for passive smokers of various ages

    International Nuclear Information System (INIS)

    Robinson, Risa J.

    2005-01-01

    Studies indicate that being exposed to second hand smoke increases the chance of developing lung cancer. Understanding the deposition of carcinogenic particles present in second hand smoke is necessary to understand the development of specific histologic type cancers. In this study, a deposition model is presented for subjects of various ages exposed to sidestream smoke. The model included particle dynamics of coagulation, hygroscopic growth, charge and cloud behavior. Concentrations were varied from the maximum measured indoor concentrations (10 6 particles/cm 3 ) to what would be expected from wisps of smoke (10 8 particles/cm 3 ). Model results agreed well with experimental data taken from human subject deposition measurements (four studies). The model results were used to determine the dose intensity (dose per unit airway surface area) of Benzo[a]pyrene (BaP) in the respiratory tract for subjects of various ages. Model predictions for BaP surface concentration on the airway walls paralleled incident rates of tumors by location in the upper tracheobronchial region. Mass deposition efficiency was found to be larger for younger subjects, consistent with diffusion being the predominant mechanism for this particle size range. However, the actual dose intensity of BaP was found to be smaller for children than adults. This occurred due to the predominant effect of the smaller initial inhaled mass for children resulting from smaller tidal volumes. The resulting model is a useful tool to predict carcinogen specific particle deposition

  20. Carcinogenic action of polycyclic hydrocarbons in animals and man

    Energy Technology Data Exchange (ETDEWEB)

    Shabad, L M

    1976-01-01

    Polycyclic hydrocarbons are universally present in the atmosphere, soil, lakes and streams, vegetation, and human and animal tissues, the concentrations varying with distance from the sources (heating systems, industrial plants, automobile highways and airports, petroleum refineries, etc.). The most potent of the carcinogens is benz(a)pyrene whose presence in an object, as shown by studies done in the author's laboratory, is an indication that other polycyclic hydrocarbons are also present. These studies also demonstrated that while benz(a)pyrene may accumulate in soil with seasonal fluctuations, it can also be destroyed by certain microorganisms. Other experiments showed that benz(a)pyrene and other such compounds can be destroyed in tissue culture as well as in vivo (e.g., benz(a)pyrene given to cows with fodder was found in their milk but not in meat after they were slaughtered). It is suggested that maximum permissible concentrations be set for benz(a)pyrene in air and water to minimize its potential carcinogenic effects.

  1. Carcinogenicity of a medicinal ozokerite and its constituents

    Energy Technology Data Exchange (ETDEWEB)

    Ruchkovskii, B; Borisiuk, I P; Tiktin, L A

    1970-01-01

    Fluorimetric analysis and skin painting tests on mice demonstrated that ceresin (a medicinal ozokerite) contains carcinogens. In the USSR, ceresin is applied to the skin or rectal and vaginal mucosa for the treatment of a variety of diseases. Ceresin and its components were tested on 460 male non-inbred mice (aged 2 to 2.5 mo) by applying either the melted substance or a 60% benzene solution of it to the skin in 30-mg doses (2 admin./week x 10 mo). Skin papillomas were produced after latent periods of 4.5 to 9 mo by paraffin, petrolatum, heavy mineral oil and 1/2 ceresin samples. Squamous cell carcinomas of the skin were seen in 2 mice painted with mineral oil. Fluorimetric analysis of ceresin demonstrated several polycyclic hydrocarbons, identified as 3,4-benzpyrene (BP) benzo(ghi) perylene, and perylene. An aqueous extract of crude ozokerite contained traces of BP, while a benzene extract contained 70 to 77 microg/kg. It is recommended that petroleum products which are commonly used to improve the consistency of ceresin be analyzed for the presence of carcinogens before use.

  2. Induction of prophage lambda by chlorinated organics: Detection of some single-species/single-site carcinogens

    Energy Technology Data Exchange (ETDEWEB)

    DeMarini, D.M.; Brooks, H.G. (Environmental Protection Agency, Research Triangle Park, NC (United States))

    1992-01-01

    Twenty-eight chlorinated organic compounds were evaluated for their ability to induce DNA damage using the Microscreen prophage-induction assay in Escherichia coli. Comparison of the performance characteristics of the prophage-induction and Salmonella assays to rodent carcinogenicity assays showed that the prophage-induction assay had a somewhat higher specificity than did the Salmonella assay (70% vs. 50%); sensitivity, concordance, and positive and negative predictivity were similar for the two microbial assays. The Microscreen prophage-induction assay failed to detect eight carcinogens, perhaps due to toxicity or other unknown factors; five of these eight carcinogens were detected by the Salmonella assay. However, the prophage-induction assay did detect six carcinogens that were not detected by the Salmonella assay, and five of these were single-species, single-site carcinogens, mostly mouse liver carcinogens. Some of these carcinogens, such as the chloroethanes, produce free radicals, which may be the basis for their carcinogenicity and ability to induce prophage. The prophage-induction (or other SOS) assay may be useful in identifying some genotoxic chlorinated carcinogens that induce DNA damage that do not revert the standard Salmonella tester strains.

  3. Potential carcinogenicity predicted by computational toxicity evaluation of thiophosphate pesticides using QSTR/QSCarciAR model.

    Science.gov (United States)

    Petrescu, Alina-Maria; Ilia, Gheorghe

    2017-07-01

    This study presents in silico prediction of toxic activities and carcinogenicity, represented by the potential carcinogenicity DSSTox/DBS, based on vector regression with a new Kernel activity, and correlating the predicted toxicity values through a QSAR model, namely: QSTR/QSCarciAR (quantitative structure toxicity relationship/quantitative structure carcinogenicity-activity relationship) described by 2D, 3D descriptors and biological descriptors. The results showed a connection between carcinogenicity (compared to the structure of a compound) and toxicity, as a basis for future studies on this subject, but each prediction is based on structurally similar compounds and the reactivation of the substructures of these compounds.

  4. 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

  5. A proposed framework for consistent regulation of public exposures to radionuclides and other carcinogens

    International Nuclear Information System (INIS)

    Kocher, D.C.; Hoffman, F.O.

    1991-01-01

    This paper discusses a proposed framework for consistent regulation of carcinogenic risks to the public based on establishing de manifestis (i.e., unacceptable) and de minimis (i.e., trivial) lifetime risks from exposure to any carcinogens at levels of about 10 -1 --10 -3 and 10 -4 --10 -6 , respectively, and reduction of risks above de minimis levels as low as reasonably achievable (ALARA). We then discuss certain differences in the way risks from exposure to radionuclides and other carcinogens currently are regulated or assessed which would need to be considered in implementing the proposed regulatory framework for all carcinogens

  6. Synergism between UV-B radiation and pathogen magnifies amphibian embryo mortality in nature

    International Nuclear Information System (INIS)

    Kiesecker, J.M.; Blaustein, R.

    1995-01-01

    Previous research has shown that amphibians have differential sensitivity to ultraviolet-B (UV-B) radiation. In some species, ambient levels of UV-B radiation cause embryonic mortality in nature. The detrimental effects of UV-B alone or with other agents may ultimately affect amphibians at the population level. Here, we experimentally demonstrate a synergistic effect between UV-B radiation and a pathogenic fungus in the field that increases the mortality of amphibian embryos compared with either factor alone. Studies investigating single factors for causes of amphibian egg mortality or population declines may not reveal the complex factors involved in declines

  7. Effects of Radon and UV Exposure on Skin Cancer Mortality in Switzerland

    Science.gov (United States)

    de Hoogh, Kees; Hauri, Dimitri; Vicedo-Cabrera, Ana M.; Schindler, Christian; Huss, Anke; Röösli, Martin

    2017-01-01

    Background: Skin cancer incidence in Switzerland is among the highest in the world. In addition to exposure to ultraviolet (UV) radiation, radon alpha particles attached to aerosols can adhere to the skin and potentially cause carcinogenic effects. Objectives: We investigated the effects of radon and UV exposure on skin cancer mortality. Methods: Cox proportional hazard regression was used to study the association between exposures and skin cancer mortality in adults from the Swiss National Cohort. Modeled radon exposure and erythemal-weighted UV dose were assigned to addresses at baseline. Effect estimates were adjusted for sex, civil status, mother tongue, education, job position, neighborhood socioeconomic position, and UV exposure from outdoor occupation. Results: The study included 5.2 million adults (mean age 48 y) and 2,989 skin cancer deaths, with 1,900 indicating malignant melanoma (MM) as the primary cause of death. Adjusted hazard ratios (HR) for MM at age 60 were 1.16 (95% CI: 1.04, 1.29) per 100Bq/m3 radon and 1.11 (1.01, 1.23) per W/m2 in UV dose. Radon effects decreased with age. Risk of MM death associated with residential UV exposure was higher for individuals engaged in outdoor work with UV exposure (HR 1.94 [1.17, 3.23]), though not statistically significantly different compared to not working outdoors (HR 1.09 [0.99, 1.21], p=0.09). Conclusions: There is considerable variation in radon and UV exposure across Switzerland. Our study suggests both are relevant risk factors for skin cancer mortality. A better understanding of the role of the UV radiation and radon exposure is of high public health relevance. https://doi.org/10.1289/EHP825 PMID:28686556

  8. Protective Role of Comfrey Leave Extracts on UV-induced Zebrafish Fin Damage.

    Science.gov (United States)

    Cheng, Chien-Chung; Chou, Chi-Yuan; Chang, Yao-Chin; Wang, Hsuan-Wen; Wen, Chi-Chung; Chen, Yau-Hung

    2014-07-01

    In zebrafish, UV exposure leads to fin malformation phenotypes including fin reduction or absence. The present study evaluated UV-protective activities of comfrey leaves extracts in a zebrafish model by recording fin morphological changes. Chemopreventive effects of comfrey leave extracts were evaluated using Kaplan-Meier analysis and Cox proportional hazards regression. The results showed that (1) the mean times of return to normal fin in the UV+comfrey (50 and 100 ppm) groups were 3.43 and 2.86 days and were quicker compared with that in the UV only group (4.21 days); (2) zebrafish fins in the UV+comfrey (50 and 100 ppm) groups were 2.05 and 3.25 times more likely to return to normal than those in the UV only group; and (3) comfrey leave extracts had UV-absorbance abilities and significantly reduced ROS production in UV-exposed zebrafish embryos, which may attenuate UV-mediated apoptosis. In conclusion, comfrey leaves extracts may have the potential to be developed as UV-protective agents to protect zebrafish embryos from UV-induced damage.

  9. Disruption of spindle checkpoint function in rats following 28 days of repeated administration of renal carcinogens.

    Science.gov (United States)

    Kimura, Masayuki; Mizukami, Sayaka; Watanabe, Yousuke; Hasegawa-Baba, Yasuko; Onda, Nobuhiko; Yoshida, Toshinori; Shibutani, Makoto

    2016-02-01

    We previously reported that 28-day exposure to hepatocarcinogens that facilitate cell proliferation specifically alters the expression of G1/S checkpoint-related genes and proteins, induces aberrant early expression of ubiquitin D (UBD) at the G2 phase, and increases apoptosis in the rat liver, indicating G1/S and spindle checkpoint dysfunction. The present study aimed to determine the time of onset of carcinogen-specific cell-cycle disruption after repeated administration of renal carcinogens for up to 28 days. Rats were orally administered the renal carcinogens nitrofurantoin (NFT), 1-amino-2,4-dibromoantraquinone (ADAQ), and 1,2,3-trichloropropane (TCP) or the non-carcinogenic renal toxicants 1-chloro-2-propanol, triamterene, and carboxin for 3, 7 or 28 days. Both immunohistochemical single-molecule analysis and real-time RT-PCR analysis revealed that carcinogen-specific expression changes were not observed after 28 days of administration. However, the renal carcinogens ADAQ and TCP specifically reduced the number of cells expressing phosphorylated-histone H3 at Ser10 in both UBD(+) cells and proliferating cells, suggestive of insufficient UBD expression at the M phase and early transition of proliferating cells from the M phase, without increasing apoptosis, after 28 days of administration. In contrast, NFT, which has marginal carcinogenic potential, did not induce such cellular responses. These results suggest that it may take 28 days to induce spindle checkpoint dysfunction by renal carcinogens; however, induction of apoptosis may not be essential. Thus, induction of spindle checkpoint dysfunction may be dependent on carcinogenic potential of carcinogen examined, and marginal carcinogens may not exert sufficient responses even after 28 days of administration.

  10. Comparison of the metabolic activation of environmental carcinogens in mouse embryonic stem cells and mouse embryonic fibroblasts

    Science.gov (United States)

    Krais, Annette M.; Mühlbauer, Karl-Rudolf; Kucab, Jill E.; Chinbuah, Helena; Cornelius, Michael G.; Wei, Quan-Xiang; Hollstein, Monica; Phillips, David H.; Arlt, Volker M.; Schmeiser, Heinz H.

    2015-01-01

    We compared mouse embryonic stem (ES) cells and fibroblasts (MEFs) for their ability to metabolically activate the environmental carcinogens benzo[a]pyrene (BaP), 3-nitrobenzanthrone (3-NBA) and aristolochic acid I (AAI), measuring DNA adduct formation by 32P-postlabelling and expression of xenobiotic-metabolism genes by quantitative real-time PCR. At 2 μM, BaP induced Cyp1a1 expression in MEFs to a much greater extent than in ES cells and formed 45 times more adducts. Nqo1 mRNA expression was increased by 3-NBA in both cell types but induction was higher in MEFs, as was adduct formation. For AAI, DNA binding was over 450 times higher in MEFs than in ES cells, although Nqo1 and Cyp1a1 transcriptional levels did not explain this difference. We found higher global methylation of DNA in ES cells than in MEFs, which suggests higher chromatin density and lower accessibility of the DNA to DNA damaging agents in ES cells. However, AAI treatment did not alter DNA methylation. Thus mouse ES cells and MEFs have the metabolic competence to activate a number of environmental carcinogens, but MEFs have lower global DNA methylation and higher metabolic capacity than mouse ES cells. PMID:25230394

  11. The effect of radiation in combination with carcinogens on the growth of normal urothelium in explant culture

    International Nuclear Information System (INIS)

    Mothersill, C.; O'Brien, A.

    1990-01-01

    Radiation is known to be carcinogenic to humans but attempts to demonstrate the process using human tissue culture models have met with little success. In the present study explants were established from urothelium and exposed to radiation and a range of chemical carcinogens, suspected promotor or metabolic agents. The resulting outgrowth was monitored for growth rate, proliferating epithelial fraction and development and differentiation of endothelial cells in culture. The results indicate that enhanced growth of epithelial cells can be seen when cultures are irradiated in the presence of various nitrosamines, benzo(a)pyrene or aniline. Radiation alone reduced the overall growth area measured but several proliferative foci developed on the resulting outgrowth. Their ultrastructural appearance reveals that they carry severe mitochondrial damage and exposure of treated cultures to metabolic inhibitors confirms that their respiration is defective. Endothelial cells proliferated over the surface of the epithelial monolayer and both the number and the degree of differentiation of the endothelial cells increased with increasing dose up to 10 Gy. While the cultures are not immortalised by the treatment, it appears that the epithelial cells have an extended lifespan (division capacity) and that a subpopulation has undergone a number of premalignant changes. Changes in endothelial cell proliferation also occur. (orig.)

  12. 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

  13. UV imaging in pharmaceutical analysis

    DEFF Research Database (Denmark)

    Østergaard, Jesper

    2018-01-01

    UV imaging provides spatially and temporally resolved absorbance measurements, which are highly useful in pharmaceutical analysis. Commercial UV imaging instrumentation was originally developed as a detector for separation sciences, but the main use is in the area of in vitro dissolution...

  14. 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.

  15. Malignant transformation in vitro: criteria, biological markers, and application in environmental screening of carcinogens

    International Nuclear Information System (INIS)

    Borek, C.

    1979-01-01

    Biological markers which distinguish malignantly transformed fibroblasts from their normal counterpart include pleomorphic morphology, lowered requirement for nutritional factors, loss of density inhibition of growth, complex topography as discernible by scanning electron microscopy, loss in surface proteins, incomplete glycosylation of membrane glycolylipids and glycoproteins, increased production of specific proteases, decreased organization of the cytoskeleton, and acquisition of neoantigens. Several of these markers are not consistently found in transformed epithelial cells and therefore cannot serve to distinguish unequivocally neoplastic epithelial cells from the normal counterparts. The only criteria associated with the transformed nature of both fibroblasts and epithelial cells are the ability of the cells to proliferate in semisolid medium and to induce tumors in appropriate hosts. In vitro systems represent a powerful tool for screening the mutagenic/oncogenic potential of physical, chemical, and environmental agents. Fibroblasts rather than epithelial cells are preferred for this purpose at the present time because of the clear-cut phenotypic differences between the normal and the transformed cells. These systems have been useful in establishing that malignant transformation can be induced by doses as low as 1 rad of X rays or 0.1 rad of neutrons, and that fractionation at low dose levelsleads to enhanced transformation. They have been useful in identifying a large number of hazardous chemicals and in evaluating the relationship between the mutagenic and carcinogenic potential of radiation and chemicals

  16. 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.

  17. Variability in DNA repair capacity in the human population and its relationship to carcinogenic risk

    International Nuclear Information System (INIS)

    Nuzzo, F.; Stefanini, M.; Giulotto, E.; Falaschi, A.

    1980-01-01

    Several inherited diseases, all characterized by a high incidence of tumours in the homozygous patients, show pronounced defects in DNA repair mechanisms, thus confirming the relationship between the repair process and mutation induction, and indicating clearly that a fraction of the population is certainly much more exposed to cancer that the bulk of the human population. The basic molecular defects in such diseases are summarized. The estimated heterozygote frequency in tumour predisposing syndromes is considered and possible identification of heterozygotes discussed. A procedure to reveal DNA repair capacity at the cellular level would perhaps identify the cancer-prone fraction of the population. A simple assay for measuring repair synthesis is outlined which can be used to determine whether a given substance or treatment elicits repair synthesis and is hence harmful to DNA and potentially mutagenic and/or carcinogenic. It can also be used to assess the capacity of an individual to respond to a known DNA damaging agent. (Auth./C.F.)

  18. Metabolism and excretion of 1-hydroxymethylpyrene, the proximate metabolite of the carcinogen 1-methylpyrene, in rats

    International Nuclear Information System (INIS)

    Bendadani, Carolin; Steinhauser, Lisa; Albert, Klaus; Glatt, Hansruedi; Monien, Bernhard H.

    2016-01-01

    1-Methylpyrene, an alkylated polycyclic aromatic hydrocarbon and environmental carcinogen, is activated by side-chain hydroxylation to 1-hydroxymethylpyrene (1-HMP) and subsequent sulfo conjugation to the DNA-reactive 1-sulfooxymethylpyrene. In addition to the bioactivation, processes of metabolic detoxification and transport greatly influence the genotoxicity of 1-methylpyrene. For a better understanding of 1-HMP detoxification in vivo we studied urinary and fecal metabolites in rats following intraperitoneal doses of 19.3 mg 1-HMP/kg body weight (5 rats) or the same dose containing 200 μCi [ 14 C]1-HMP/kg body weight (2 rats). After 48 h, 48.0% (rat 1) and 29.1% (rat 2) of the radioactivity was recovered as 1-HMP in the feces. Six major metabolites were observed by UV and on-line radioactivity detection in urine samples and feces after HPLC separation. The compounds were characterized by mass spectrometry, 1 H NMR and 1 H- 1 H COSY NMR spectroscopy, which allowed assigning tentative molecular structures. Two prominent metabolites, 1-pyrene carboxylic acid (M-6) and the acyl glucuronide of 1-pyrene carboxylic acid (M-5) accounted for 17.7% (rat 1) and 25.2% (rat 2) of the overall radioactive dose. Further, we detected the acyl glucuronide of 6-hydroxy-1-pyrene carboxylic acid (M-1) and 8-sulfooxy-1-pyrene carboxylic acid (M-3) together with two regioisomers of M-3 (M-2 and M-4) differing in position of the sulfate group at the pyrene ring. In urine samples, the radioactivity of 1-pyrene carboxylic acid and its five derivatives amounted to 32.4% (rat 1) or 45.5% (rat 2) of the total [ 14 C]1-HMP dose.

  19. Evaluation of Combined Peracetic acid and UV treatment for ...

    Science.gov (United States)

    The current study evaluates the effectiveness of the combined application of Peracetic acid and ultraviolet radiation as alternative disinfectant agents to the traditional chlorination of wastewater effluents. Various pathogens (E. coli, enterococci and fecal coliforms) were evaluated in the study. Four experiments were conducted using low to high PAA levels and UV dosages. E. coli and enterococci were resistant to low to moderate PAA dosage (0.5- 1 mg/L). These microbes can be removed effectively at high PAA dosage (2.5 mg/L) with 30 min contact time. Fecal coliforms were completely inactivated even at a low PAA dose of 0.7 mg/L. E. coli was more susceptible to UV disinfection than enterococci at low UV dosages. Enterococci required at least 40 mJ/cm2 for 2.5 log inactivation. In combined PAA + UV treatment, low UV intensities between 7 – 40 mJ/cm2 showed poor disinfection performance at a low PAA concentration of 1.5 mg/L. High UV intensities of 120 and 60 mJ/cm2 inactivated all the pathogens to below detection levels even at low to moderate PAA (0.7 mg/L and 1 mg/L) pretreatment concentration. Combined PAA + UV treatment at 1 mg/L (for 15 and 30 min contact time) + 120 and 60 mJ/cm2 did not show any regrowth of microbes, whereas PAA only disinfection with 15 min contact time showed regrowth of enterococci and fecal coliforms. UV only disinfection showed E. coli regrowth. • This pilot scale study was designed for providing necessary parameter optimization

  20. The mechanisms of UV mutagenesis

    International Nuclear Information System (INIS)

    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. (author)

  1. Deep UV LEDs

    Science.gov (United States)

    Han, Jung; Amano, Hiroshi; Schowalter, Leo

    2014-06-01

    Deep ultraviolet (DUV) photons interact strongly with a broad range of chemical and biological molecules; compact DUV light sources could enable a wide range of applications in chemi/bio-sensing, sterilization, agriculture, and industrial curing. The much shorter wavelength also results in useful characteristics related to optical diffraction (for lithography) and scattering (non-line-of-sight communication). The family of III-N (AlGaInN) compound semiconductors offers a tunable energy gap from infrared to DUV. While InGaN-based blue light emitters have been the primary focus for the obvious application of solid state lighting, there is a growing interest in the development of efficient UV and DUV light-emitting devices. In the past few years we have witnessed an increasing investment from both government and industry sectors to further the state of DUV light-emitting devices. The contributions in Semiconductor Science and Technology 's special issue on DUV devices provide an up-to-date snapshot covering many relevant topics in this field. Given the expected importance of bulk AlN substrate in DUV technology, we are pleased to include a review article by Hartmann et al on the growth of AlN bulk crystal by physical vapour transport. The issue of polarization field within the deep ultraviolet LEDs is examined in the article by Braut et al. Several commercial companies provide useful updates in their development of DUV emitters, including Nichia (Fujioka et al ), Nitride Semiconductors (Muramoto et al ) and Sensor Electronic Technology (Shatalov et al ). We believe these articles will provide an excellent overview of the state of technology. The growth of AlGaN heterostructures by molecular beam epitaxy, in contrast to the common organo-metallic vapour phase epitaxy, is discussed by Ivanov et al. Since hexagonal boron nitride (BN) has received much attention as both a UV and a two-dimensional electronic material, we believe it serves readers well to include the

  2. 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.

  3. Dose-response relationships for carcinogens: a review

    International Nuclear Information System (INIS)

    Zeise, L.; Wilson, R.; Crouch, E.A.C.

    1987-01-01

    The authors review the experimental evidence for various shapes of dose-response relationships for carcinogens and summarize those experiments that give the most information on relatively low doses. A brief review of some models is given to illustrate the shapes of dose-response curve expected from them. Their major interest is in the use of dose-response relationships to estimate risks to humans at low doses, and so they pay special attention to experimentally observed and theoretically expected nonlinearities. There are few experimental examples of nonlinear dose-response relations in humans, but this may simply be due to the limitations in the data. The several examples in rodents, even though for high dose data, suggest that nonlinearity is common. In some cases such nonlinearities may be rationalized on the basis of the pharmacokinetics of the test compound or its metabolites

  4. Chemistry of mutagens and carcinogens in broiled food.

    Science.gov (United States)

    Nishimura, S

    1986-01-01

    From a chemical point of view, the following subjects are important areas in studies on mutagens and carcinogens in broiled foods. In addition to heterocyclic amines which need microsomal activation, the structural elucidation of more labile direct-acting mutagens is necessary. It is known that there are still various unknown minor mutagens in broiled foods. Although the structural characterization of such compounds is more difficult, it is important since they might be hazardous in spite of their low mutagenicity. A more feasible and easier method for quantitative analysis of mutagens, in addition to HPLC and GC/MS methods presently employed, must be developed. The mechanism of formation of mutagens by broiling of food should be studied. An effective chemical method to prevent formation of mutagens or to destroy them, once formed, should be developed. PMID:3757944

  5. The assessment of the carcinogenic effects of low dose radiation

    International Nuclear Information System (INIS)

    Tubiana, M.; Lafuma, J.; Masse, R.; Latarjet, R.

    1991-01-01

    It is concluded that the exclusion of patients for the purposes of risk estimation, the choice of a particular relative risk projection model and of a dose reduction factor equal to 2 are all decisions which result in an overestimation of the actual risk. These choices can be understood when the aim is radiation protection and when it is safer to overestimate the risk; however, they are open to criticism if the aim is a realistic assessment of the risk. For low doses, below 50 mSv/year, and when all causes of uncertainty are added, the actual risk might be markedly lower than the risk estimated with the ICRP (1991) carcinogenic risk coefficient and the DRF estimated by ICRP. Future studies should aim at providing direct and more precise assessments of risk coefficients in the low dose region. (Author)

  6. [Comparative carcinogenic properties of basalt fiber and chrysotile-asbestos].

    Science.gov (United States)

    Nikitina, O V; Kogan, F M; Vanchugova, N N; Frash, V N

    1989-01-01

    In order to eliminate asbestos adverse effect on workers' health it was necessary to use mineral rayon, primarily basalt fibre, instead of asbestos. During a chronic experiment on animals the oncogenicity of 2 kinds of basalt fibre was studied compared to chrysotile asbestos. The dust dose of 25 mg was twice administered by intraperitonial route. All types of dust induced the onset of intraperitonial mesotheliomas but neoplasm rates were significantly lower in the groups exposed to basalt fibre. There was no credible data on the differences between the groups exposed to various types of basalt fibre. Since the latter produced some oncogenic effect, it was necessary to develop a complex of antidust measures, fully corresponding to the measures adopted for carcinogenic dusts.

  7. Nuclear DNA synthesis rate and labelling index: effects of carcinogenic and non-carcinogenic chemicals on its behaviour in the organism of growing CBA mice

    International Nuclear Information System (INIS)

    Amlacher, E.; Rudolph, C.

    1978-01-01

    Well known bioassays have been compared with the author's thymidine incorporation-screening system and other assays based on biochemical quantification of DNA synthesis as a possibility of identification of carcinogens. The partial inhibition of the whole DNA synthesis in a proliferating cell population after treatment with toxic and carcinogenic chemicals is an early common response especially in hepatectomized animal, livers caused by the effects of those substances. However, by quantitative evaluation of the nuclear DNA synthesis rate as a basic parameter, using autoradiographs of kidney and liver of juvenile growing CBA mice, it is possible to differentiate carcinogenic from non-carcinogenic chemicals by means of silver grain counting after 3 H-TdR incorporation. On the contrary, the whole DNA synthesis, expressed by the 3 H-labelling index (in per cent) of kidney and liver, did not permit such a differentiation in the experimental arrangement used. It could be demonstrated that carcinogenic compounds of different chemical classes partially inhibit the nuclear DNA synthesis rate significantly over a period of more than 24 hours. The tested non-carcinogenic compounds did not show this suppressive effect on the nuclear DNA synthesis rate. (author)

  8. Distribution of methyl and ethyl adducts following alkylation with monofunctional alkylating agents.

    Science.gov (United States)

    Beranek, D T

    1990-07-01

    Alkylating agents, because of their ability to react directly with DNA either in vitro or in vivo, or following metabolic activation as in the case of the dialkylnitrosamines, have been used extensively in studying the mechanisms of mutagenicity and carcinogenicity. Their occurrence is widespread in the environment and human exposure from natural and pollutant sources is universal. Since most of these chemicals show varying degrees of both carcinogenicity and mutagenicity, and exhibit compound-specific binding patterns, they provide an excellent model for studying molecular dosimetry. Molecular dosimetry defines dose as the number of adducts bound per macromolecule and relates the binding of these adducts to the human mutagenic or carcinogenic response. This review complies DNA alkylation data for both methylating and ethylating agents in a variety of systems and discusses the role these alkylation products plays in molecular mutagenesis.

  9. Changing the field of carcinogenicity testing of human pharmaceuticals by emphasizing mode of action

    NARCIS (Netherlands)

    Laan, J.W. van der; Duijndam, B.; Hoorn, T. van den; Woutersen, R.; Water, B. van de

    2017-01-01

    Lifetime testing for carcinogenicity of pharmaceuticals in rodents has been a controversial issue since the start of the International Conference on Harmonisation in 1990. Since 2010 the debate reached a new level following the proposal that a negative outcome of carcinogenicity studies can be

  10. 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...

  11. Impact of occupational carcinogens on lung cancer risk in a general population

    NARCIS (Netherlands)

    De Matteis, S.; Consonni, D.; Lubin, J.H.; Tucker, M.; Peters, S.; Vermeulen, R.; Kromhout, H.; Bertazzi, P.A.; Caporaso, N.E.; Pesatori, A.C.; Wacholder, S.; Landi, M.T.

    2012-01-01

    BACKGROUND: Exposure to occupational carcinogens is an important preventable cause of lung cancer. Most of the previous studies were in highly exposed industrial cohorts. Our aim was to quantify lung cancer burden attributable to occupational carcinogens in a general population. METHODS: We applied

  12. 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. Copyright © 2012 Elsevier GmbH. All rights reserved.

  13. 78 FR 16681 - International Conference on Harmonisation; Proposed Change to Rodent Carcinogenicity Testing of...

    Science.gov (United States)

    2013-03-18

    ...-evidence (WOE) factors proposed for inclusion in CADs. II. Past Experience With Carcinogenicity Assessment... Medicines Agency; and the Japanese Ministry of Health, Labour and Welfare. We would request that CADs be... WOE factors proposed for inclusion in carcinogenicity assessment documents. Submit either electronic...

  14. Occurrence and profiles of organic sun-blocking agents in surface waters and sediments in Japanese rivers and lakes

    International Nuclear Information System (INIS)

    Kameda, Yutaka; Kimura, Kumiko; Miyazaki, Motonobu

    2011-01-01

    Sun-blocking agents including eight UV filters (UVF) and 10 UV light stabilizers (UVLS) were measured in water and sediment collected from 22 rivers, four sewage treatment plant effluents (STPE) and three lakes in Japan. Total sun blocking agents levels ranged from N.D. to 4928 ng/L and from 2.0 to 3422 μg/kg dry wt in surface water and in sediment, respectively. Benzyl salicylate, benzophenone-3, 2-ethyl hexyl-4-methoxycinnamte (EHMC) and octyl salicylate were dominant in surface water receiving wastewater effluents and STPE, although UV-328, benzophenone and EHMC were dominant in other surface water except background sites. Three UVF and nine UVLS were observed from all sediment and their compositions showed similar patterns with UV-328 and UV-234 as the most prevalent compounds. Homosalate, octocrylene, UV-326, UV-327, UV-328 and UV-234 were significantly correlated with Galaxolide in sediments. Concentrations of UV-327 and UV-328 also had strong correlation between those of UV-326 in sediment. - Highlights: → Total sun-blocking agents levels ranged from N.D. to 4928 ng/L in surface water from 29 sampling sites. → The maximum concentration of total sun-blocking agents was 3422 μg/kg dry wt. in sediment. → Residential wastewaters and STPE were considered to be potential sources of UVLS in river and lakes. → Most of sun-blocking agents in sediment were significantly correlated with HHCB. → UV-326 had a strong linear correlation between UV-327 as well as UV-328 in all sediment. - Occurrence of eight UV filters and 10 UV light stabilizers in surface water and sediment were investigated and characterized their compositions in water and sediment.

  15. Moesin Is a Biomarker for the Assessment of Genotoxic Carcinogens in Mouse Lymphoma

    Science.gov (United States)

    Lee, Yoen Jung; Choi, In-Kwon; Sheen, Yhun Yhong; Park, Sue Nie; Kwon, Ho Jeong

    2012-01-01

    1,2-Dibromoethane and glycidol are well known genotoxic carcinogens, which have been widely used in industry. To identify a specific biomarker for these carcinogens in cells, the cellular proteome of L5178Y mouse lymphoma cells treated with these compounds was analyzed by 2-dimensional gel electrophoresis (2-DE) and MALDI-TOF mass spectrometry (MS). Of 50 protein spots showing a greater than 1.5-fold increase or decrease in intensity compared to control cells on a 2-D gel, we focused on the candidate biomarker moesin. Western analysis using monoclonal rabbit anti-moesin confirmed the identity of the protein and its increased level of expression upon exposure to the carcinogenic compounds. Moesin expression also increased in cells treated with six additional genotoxic carcinogens, verifying that moesin could serve as a biomarker to monitor phenotypic change upon exposure to genotoxic carcinogens in L5178Y mouse lymphoma cells. PMID:22358511

  16. 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

    A Drug Information Association (DIA) workshop was held in May 2001 to discuss the outcome of the International Life Sciences Institute-Health and Environmental Sciences Institute (ILSI-HESI) project on alternative models for carcinogenicity assessment such as the P53(+/-) and XPA(+/-) knockout...... 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...

  17. [Biological agents].

    Science.gov (United States)

    Amano, Koichi

    2009-03-01

    There are two types of biological agents for the treatment of rheumatoid arthritis (RA); monoclonal antibodies and recombinant proteins. Among the latter, etanercept, a recombinant fusion protein of soluble TNF receptor and IgG was approved in 2005 in Japan. The post-marketing surveillance of 13,894 RA patients revealed the efficacy and safety profiles of etanercept in the Japanese population, as well as overseas studies. Abatacept, a recombinant fusion protein of CTLA4 and IgG, is another biological agent for RA. Two clinical trials disclosed the efficacy of abatacept for difficult-to-treat patients: the AIM for MTX-resistant cases and the ATTAIN for patients who are resistant to anti-TNF. The ATTEST trial suggested abatacept might have more acceptable safety profile than infliximab. These biologics are also promising for the treatment of RA for not only relieving clinical symptoms and signs but retarding structural damage.

  18. UV Photography Shows Hidden Sun Damage

    Science.gov (United States)

    ... mcat1=de12", ]; for (var c = 0; c UV photography shows hidden sun damage A UV photograph gives ... developing skin cancer and prematurely aged skin. Normal photography UV photography 18 months of age: This boy's ...

  19. Sun, UV Radiation and Your Eyes

    Science.gov (United States)

    ... Sunglasses Sun Smart UV Safety Infographic The Sun, UV Radiation and Your Eyes Leer en Español: El ... Aug. 28, 2014 Keep an Eye on Ultraviolet (UV) Safety Eye medical doctors (ophthalmologists) caution us that ...

  20. UV survival of human mycoplasmas

    International Nuclear Information System (INIS)

    Aoki, Shigeji; Ito, Shoko; Watanabe, Takehiko

    1979-01-01

    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)

  1. Experimental and Theoretical Investigation of Effects of Ethanol and Acetic Acid on Carcinogenic NDMA Formation in Simulated Gastric Fluid.

    Science.gov (United States)

    Zhang, Ou; Zou, Xuan; Li, Qi-Hong; Sun, Zhi; Liu, Yong Dong; Zhong, Ru Gang

    2016-07-07

    N-nitrosodimethylamine (NDMA), as a representative of endogenously formed N-nitroso compounds (NOCs), has become the focus of considerable research interest due to its unusually high carcinogenicity. In this study, effects of ethanol and acetic acid on the formation of NDMA from dimethylamine (DMA) and nitrite in simulated gastric fluid (SGF) were investigated. Experimental results showed that ethanol in the concentrations of 1-8% (v/v) and acetic acid in the concentrations of 0.01-8% (v/v) exhibit inhibitory and promotion effects on the formation of NDMA, respectively. Moreover, they are both in a dose-dependent manner with the largest inhibition/promotion rate reaching ∼70%. Further experimental investigations indicate that ethanol and acetic acid are both able to scavenge nitrite in SGF. It implies that there are interactions of ethanol and acetic acid with nitrite or nitrite-related nitrosating agents rather than DMA. Theoretical calculations confirm the above experimental results and demonstrate that ethanol and acetic acid can both react with nitrite-related nitrosating agents to produce ethyl nitrite (EtONO) and acetyl nitrite (AcONO), respectively. Furthermore, the reactivities of ethyl nitrite, acetyl nitrite, and dinitrogen trioxide reacting with DMA were found in the order of AcONO > N2O3 ≫ EtONO. This is probably the main reason why there are completely different effects of ethanol and acetic acid on NDMA formation. On the basis of the above results, two requirements for a potential inhibitor of NOCs formation in SGF were provided. The results obtained in this study will be helpful in better understanding the inhibition/promotion mechanisms of compounds on NDMA formation in SGF and searching for protective substances to prevent carcinogenic NOCs formation.

  2. Aerosol effects on UV radiation

    International Nuclear Information System (INIS)

    Koepke, P.; Reuder, J.; Schwander, H.

    2000-01-01

    The reduction of erythemally weighted UV-irradiance (given as UV index, UVI) due to aerosols is analyzed by variation of the tropospheric particles in a wide, but realistic range. Varied are amount and composition of the particles and relative humidity and thickness of the mixing layer. The reduction of UVI increases with aerosol optical depth and the UV change is around 10% for a change aerosol optical depth from 0.25 to 0.1 and 0.4 respectively. Since both aerosol absorption and scattering are of relevance, the aerosol effect depends besides total aerosol amount on relative amount of soot and on relative humidity

  3. Rapid and preferential activation of the c-jun gene during the mammalian UV response

    International Nuclear Information System (INIS)

    Devary, Y.; Gottlieb, R.A.; Lau, L.F.; Karin, M.

    1991-01-01

    Exposure of mammalian cells to DNA-damaging agents leads to activation of a genetic response known as the UV response. Because several previously identified UV-inducible genes contain AP-1 binding sites within their promoters, we investigated the induction of AP-1 activity by DNA-damaging agents. We found that expression of both c-jun and c-fos, which encode proteins that participate in formation of the AP-1 complex, is rapidly induced by two different DNA-damaging agents: UV and H2O2. Interestingly, the c-jun gene is far more responsive to UV than any other immediate-early gene that was examined, including c-fos. Other jun and fos genes were only marginally affected by UV or H2O2. Furthermore, UV is a much more efficient inducer of c-jun than phorbol esters, the standard inducers of c-jun expression. This preferential response of the c-jun gene is mediated by its 5' control region and requires the TPA response element, suggesting that this element also serves as an early target for the signal transduction pathway elicited by DNA damage. Both UV and H2O2 lead to a long-lasting increase in AP-1 binding activity, suggesting that AP-1 may mediate the induction of other damage-inducible genes such as human collagenase

  4. 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)

    Gamer, A.O.

    1988-02-01

    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.) [de

  5. Mechanistic Insight into the Degradation of Nitrosamines via Aqueous-Phase UV Photolysis or a UV-Based Advanced Oxidation Process: Quantum Mechanical Calculations

    Directory of Open Access Journals (Sweden)

    Daisuke Minakata

    2018-02-01

    Full Text Available Nitrosamines are a group of carcinogenic chemicals that are present in aquatic environments that result from byproducts of industrial processes and disinfection products. As indirect and direct potable reuse increase, the presence of trace nitrosamines presents challenges to water infrastructures that incorporate effluent from wastewater treatment. Ultraviolet (UV photolysis or UV-based advanced oxidation processes that produce highly reactive hydroxyl radicals are promising technologies to remove nitrosamines from water. However, complex reaction mechanisms involving radicals limit our understandings of the elementary reaction pathways embedded in the overall reactions identified experimentally. In this study, we perform quantum mechanical calculations to identify the hydroxyl radical-induced initial elementary reactions with N-nitrosodimethylamine (NDMA, N-nitrosomethylethylamine, and N-nitrosomethylbutylamine. We also investigate the UV-induced NDMA degradation mechanisms. Our calculations reveal that the alkyl side chains of nitrosamine affect the reaction mechanism of hydroxyl radicals with each nitrosamine investigated in this study. Nitrosamines with one- or two-carbon alkyl chains caused the delocalization of the electron density, leading to slower subsequent degradation. Additionally, three major initial elementary reactions and the subsequent radical-involved reaction pathways are identified in the UV-induced NDMA degradation process. This study provides mechanistic insight into the elementary reaction pathways, and a future study will combine these results with the kinetic information to predict the time-dependent concentration profiles of nitrosamines and their transformation products.

  6. Mechanistic Insight into the Degradation of Nitrosamines via Aqueous-Phase UV Photolysis or a UV-Based Advanced Oxidation Process: Quantum Mechanical Calculations.

    Science.gov (United States)

    Minakata, Daisuke; Coscarelli, Erica

    2018-02-28

    Nitrosamines are a group of carcinogenic chemicals that are present in aquatic environments that result from byproducts of industrial processes and disinfection products. As indirect and direct potable reuse increase, the presence of trace nitrosamines presents challenges to water infrastructures that incorporate effluent from wastewater treatment. Ultraviolet (UV) photolysis or UV-based advanced oxidation processes that produce highly reactive hydroxyl radicals are promising technologies to remove nitrosamines from water. However, complex reaction mechanisms involving radicals limit our understandings of the elementary reaction pathways embedded in the overall reactions identified experimentally. In this study, we perform quantum mechanical calculations to identify the hydroxyl radical-induced initial elementary reactions with N -nitrosodimethylamine (NDMA), N -nitrosomethylethylamine, and N -nitrosomethylbutylamine. We also investigate the UV-induced NDMA degradation mechanisms. Our calculations reveal that the alkyl side chains of nitrosamine affect the reaction mechanism of hydroxyl radicals with each nitrosamine investigated in this study. Nitrosamines with one- or two-carbon alkyl chains caused the delocalization of the electron density, leading to slower subsequent degradation. Additionally, three major initial elementary reactions and the subsequent radical-involved reaction pathways are identified in the UV-induced NDMA degradation process. This study provides mechanistic insight into the elementary reaction pathways, and a future study will combine these results with the kinetic information to predict the time-dependent concentration profiles of nitrosamines and their transformation products.

  7. UV/EB curable psa's

    International Nuclear Information System (INIS)

    Glotfelter, C.A.

    1995-01-01

    The author describe both water-based and 100% solids UV/EB curable PSA's (Pressure Sensitive Adhesives) and their properties. A new acrylate monomer, ethoxylated nonyl phenol acrylate, has great utility in the formulation of water-based PSA's

  8. Can creatine supplementation form carcinogenic heterocyclic amines in humans?

    Science.gov (United States)

    Pereira, Renato Tavares dos Santos; Dörr, Felipe Augusto; Pinto, Ernani; Solis, Marina Yazigi; Artioli, Guilherme Giannini; Fernandes, Alan Lins; Murai, Igor Hisashi; Dantas, Wagner Silva; Seguro, Antônio Carlos; Santinho, Mirela Aparecida Rodrigues; Roschel, Hamilton; Carpentier, Alain; Poortmans, Jacques Remi; Gualano, Bruno

    2015-01-01

    Abstract Creatine supplementation has been associated with increased cancer risk. In fact, there is evidence indicating that creatine and/or creatinine are important precursors of carcinogenic heterocyclic amines (HCAs). The present study aimed to investigate the acute and chronic effects of low- and high-dose creatine supplementation on the production of HCAs in healthy humans (i.e. 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (8-MeIQx),  2-amino-(1,6-dimethylfuro[3,2-e]imidazo[4,5-b])pyridine (IFP) and 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (4,8-DiMeIQx)). This was a non-counterbalanced single-blind crossover study divided into two phases, in which low- and high-dose creatine protocols were tested. After acute (1 day) and chronic supplementation (30 days), the HCAs PhIP, 8-MeIQx, IFP and 4,8-DiMeIQx were assessed through a newly developed HPLC–MS/MS method. Dietary HCA intake and blood and urinary creatinine were also evaluated. Out of 576 assessments performed (from 149 urine samples), only nine (3 from creatine and 6 from placebo) showed quantifiable levels of HCAs (8-MeIQx: n = 3; 4,8-DiMeIQx: n = 2; PhIP: n = 4). Individual analyses revealed that diet rather than creatine supplementation was the main responsible factor for HCA formation in these cases. This study provides compelling evidence that both low and high doses of creatine supplementation, given either acutely or chronically, did not cause increases in the carcinogenic HCAs PhIP, 8-MeIQx, IFP and 4,8-DiMeIQx in healthy subjects. These findings challenge the long-existing notion that creatine supplementation could potentially increase the risk of cancer by stimulating the formation of these mutagens. Key points There is a long-standing concern that creatine supplementation could be associated with cancer, possibly by facilitating the formation of carcinogenic heterocyclic amines (HCAs). This study provides compelling evidence

  9. 78 FR 44117 - Notice of a Public Comment Period on the Draft IRIS Carcinogenicity Assessment for Ethylene Oxide

    Science.gov (United States)

    2013-07-23

    ... Public Comment Period on the Draft IRIS Carcinogenicity Assessment for Ethylene Oxide AGENCY... Carcinogenicity of Ethylene Oxide'' (EPA/635/R-13/128a) and on the draft peer review charge questions. The draft... on the draft Evaluation of the Inhalation Carcinogenicity of Ethylene Oxide and on the draft peer...

  10. 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

  11. INTEGRATION OF QSAR AND SAR METHODS FOR THE MECHANISTIC INTERPRETATION OF PREDICTIVE MODELS FOR CARCINOGENICITY

    Directory of Open Access Journals (Sweden)

    Natalja Fjodorova

    2012-07-01

    Full Text Available The knowledge-based Toxtree expert system (SAR approach was integrated with the statistically based counter propagation artificial neural network (CP ANN model (QSAR approach to contribute to a better mechanistic understanding of a carcinogenicity model for non-congeneric chemicals using Dragon descriptors and carcinogenic potency for rats as a response. The transparency of the CP ANN algorithm was demonstrated using intrinsic mapping technique specifically Kohonen maps. Chemical structures were represented by Dragon descriptors that express the structural and electronic features of molecules such as their shape and electronic surrounding related to reactivity of molecules. It was illustrated how the descriptors are correlated with particular structural alerts (SAs for carcinogenicity with recognized mechanistic link to carcinogenic activity. Moreover, the Kohonen mapping technique enables one to examine the separation of carcinogens and non-carcinogens (for rats within a family of chemicals with a particular SA for carcinogenicity. The mechanistic interpretation of models is important for the evaluation of safety of chemicals.

  12. Approaches to the risk assessment of genotoxic carcinogens in food: a critical appraisal.

    Science.gov (United States)

    O'Brien, J; Renwick, A G; Constable, A; Dybing, E; Müller, D J G; Schlatter, J; Slob, W; Tueting, W; van Benthem, J; Williams, G M; Wolfreys, A

    2006-10-01

    The present paper examines the particular difficulties presented by low levels of food-borne DNA-reactive genotoxic carcinogens, some of which may be difficult to eliminate completely from the diet, and proposes a structured approach for the evaluation of such compounds. While the ALARA approach is widely applicable to all substances in food that are both carcinogenic and genotoxic, it does not take carcinogenic potency into account and, therefore, does not permit prioritisation based on potential risk or concern. In the absence of carcinogenicity dose-response data, an assessment based on comparison with an appropriate threshold of toxicological concern may be possible. When carcinogenicity data from animal bioassays are available, a useful analysis is achieved by the calculation of margins of exposure (MOEs), which can be used to compare animal potency data with human exposure scenarios. Two reference points on the dose-response relationship that can be used for MOE calculation were examined; the T25 value, which is derived from linear extrapolation, and the BMDL10, which is derived from mathematical modelling of the dose-response data. The above approaches were applied to selected food-borne genotoxic carcinogens. The proposed approach is applicable to all substances in food that are DNA-reactive genotoxic carcinogens and enables the formulation of appropriate semi-quantitative advice to risk managers.

  13. Carcinogenicity of petroleum lubricating oil distillates: effects of solvent refining, hydroprocessing, and blending.

    Science.gov (United States)

    Halder, C A; Warne, T M; Little, R Q; Garvin, P J

    1984-01-01

    Certain refining processes were investigated to determine their influence on the dermal carcinogenic activity of petroleum-derived lubricating oil distillates. Specifically, the effects of solvent refining, hydroprocessing, a combination of both processes, and the blending of oils processed using each technique were evaluated in standard mouse skin-painting bioassays. The refining process used as well as the level or severity of treatment greatly influenced the carcinogenic outcome of processed lubricating oils. Solvent refining at severities normally used appeared to eliminate carcinogenicity. In contrast, hydroprocessing alone at mild levels of treatment was successful only in reducing the carcinogenic potency; severe hydroprocessing conditions were necessary to eliminate carcinogenic activity without the use of additional refining processes. Carcinogenic activity could also be eliminated by following moderate solvent refining with mild hydroprocessing. Blending of hydroprocessed oils with solvent-refined oils resulted in a substantial reduction or even elimination of carcinogenic activity. However, the degree of protection obtained varied with the particular distillates used and appeared largely dependent on the inherent biological activity of the hydroprocessed oil.

  14. Identification of Radiation Effects on Carcinogenic Food Estimated by Ames Test

    International Nuclear Information System (INIS)

    Afifi, M.; Eid, I.; El - Nagdy, M.; Zaher, R.; Abd El-Karem, H.; Abd EL Karim, A.

    2016-01-01

    A major concern in studies related to carcinogenesis is the exposure to the exogenous carcinogens that may occur in food in both natural and polluted human environments. The purpose of the present study is to examine some of food products by Ames test to find out if food products carcinogenic then expose food to gamma radiation to find out the effect of radiation on it as a treatment. In this study, the food samples were examined by Ames test (Salmonella typhimurium mutagenicity test) to find out that a food product could be carcinogenic or highly mutated. Testing of chemicals for mutagenicity is based on the knowledge that a substance which is mutagenic in the bacterium is more likely than not to be a carcinogen in laboratory animals, and thus , by extension, present a risk of cancer to humans. After that food products that showed mutagenicity exposed to gamma radiation at different doses to examine the effect of gamma radiation on food products. This study represent γ radiation effect on carcinogenic food by using Ames test in the following steps: Detect food by Ames test using Salmonella typhimurium strains in which the colony count /plate for each food sample will show if food is slightly mutated or highly mutated or carcinogenic. If food is highly mutated or carcinogenic with high number of colonies /plate, then the carcinogenic food or highly mutated food exposed to different doses of radiation The applied doses in this study were 0, 2.5, 5, and 10 (KGy). Detect the radiation effect on food samples by Ames test after irradiation. The study shows that mutated and carcinogenic food products estimated by Ames test could be treated by irradiation

  15. 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.

  16. Advances in Carcinogenic Metal Toxicity and Potential Molecular Markers

    Directory of Open Access Journals (Sweden)

    Preeyaporn Koedrith

    2011-12-01

    Full Text Available Metal compounds such as arsenic, cadmium, chromium, cobalt, lead, mercury, and nickel are classified as carcinogens affecting human health through occupational and environmental exposure. However, the underlying mechanisms involved in tumor formation are not well clarified. Interference of metal homeostasis may result in oxidative stress which represents an imbalance between production of free radicals and the system’s ability to readily detoxify reactive intermediates. This event consequently causes DNA damage, lipid peroxidation, protein modification, and possibly symptomatic effects for various diseases including cancer. This review discusses predominant modes of action and numerous molecular markers. Attention is paid to metal-induced generation of free radicals, the phenomenon of oxidative stress, damage to DNA, lipid, and proteins, responsive signal transduction pathways with major roles in cell growth and development, and roles of antioxidant enzymatic and DNA repair systems. Interaction of non-enzymatic antioxidants (carotenoids, flavonoids, glutathione, selenium, vitamin C, vitamin E, and others with cellular oxidative stress markers (catalase, glutathione peroxidase, and superoxide dismutase as well as certain regulatory factors, including AP-1, NF-κB, Ref-1, and p53 is also reviewed. Dysregulation of protective pathways, including cellular antioxidant network against free radicals as well as DNA repair deficiency is related to oncogenic stimulation. These observations provide evidence that emerging oxidative stress-responsive regulatory factors and DNA repair proteins are putative predictive factors for tumor initiation and progression.

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

    International Nuclear Information System (INIS)

    Ohnishi, Takeo

    1986-01-01

    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.)

  18. Sunscreen Agents in the Environment: Determination by HPLC-ESI-MS/MS and GC-MS and Calculation of Phototoxicity

    Science.gov (United States)

    Ultraviolet (UV) filters, also known as sunscreen agents, are chemicals widely used in cosmetics, sunscreens, and plastics to block UV radiation from the sun. There have been studies that show some sunscreen agents demonstrate estrogenicity and multiple hormonal activities in vi...

  19. Two-components UV-therapy

    International Nuclear Information System (INIS)

    Pullmann, H.; Steigleder, G.K.

    1980-01-01

    20 patients with generalized psoriasis were treated with an apparatus containing UV-A- and UV-B-fluorescence tubes to be switched separately. The therapy was started with an UV-A-dose of 12 J/cm 2 daily. After the first week of treatment UV-B in increasing doses was applicated additionally. Clearance was achieved in 80 percent. (orig.) [de

  20. The evolutionary response of plants to increased UV-B radiation: Field studies with Arabidopsis thaliana

    International Nuclear Information System (INIS)

    Trumbull, V.L.; Paige, K.N.

    1995-01-01

    The response of a species to any environmental change is determined by both phenotypic and evolutionary adjustments. To date, the majority of research concerning the response of terrestrial plants to increased UV-B radiation has focused on phenotypic adjustments. Recently we have initiated field studies aimed at assessing genetic variation for UV-B sensitivity within a natural population of Arabidopsis thaliana. This population consists of at least eight discrete genotypes that have been confirmed by RAPD analysis. We used an incomplete block design to assess the impact of UV-B (ambient and ambient + 6 kJ) and PAR (low and high) on these genotypes. The high UV-B treatment caused a significant reduction in fruit number and plant height while the high PAR treatment caused a significant increase in these variables. In addition, there was a marginally significant (p=0.1) UV-B x PAR x maternal line interaction for fruit number, indicating that genetic variation for UV-B sensitivity within this population depends on the PAR environment. The combination of high UV-B and high PAR caused a change in fruit number (relative to the ambient UV-B/high PAR treatment) ranging from an increase of 24% to a decrease of 47%. This range was much smaller in the low PAR treatment. These results indicate the potential for increased UV-B radiation to act as an agent of natural selection within this population

  1. 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.

  2. 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.

  3. A Study of UV Resistance of a Water-based Polyurethane Lacquer Containing Nano Ceria

    Directory of Open Access Journals (Sweden)

    Arash Saadat-Monfared

    2013-01-01

    Full Text Available Cerium oxide (Ceria nano particle, as photodegradation prevention agent was studied in water-based polyurethane clear coat  systems. Polyurethane coatings show superior weathering resistance compared with acrylic melamine systems. However, any chemical change has detrimental effects on the property profile of PU coatings. Coatings containing various amounts of cerium oxide nanoparticles were prepared and their weathering resistance was evaluated using simulated UV cabinet. To this end the extent and mechanism of degradation was studied utilizing UV-Vis and FTIR-ATR spectroscopy as well as DMTA analysis. The results revealed that Ceria nano particles with concentration of 1.44 % (wt absorb beyond 92.5% of UV light of UV-B region and showed an efficiency of 2000 times as of organic UV absorbers.

  4. Excimer UV curing in printing

    International Nuclear Information System (INIS)

    Mehnert, R.

    1999-01-01

    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

  5. UV-indeks og dets betydning

    DEFF Research Database (Denmark)

    Wulf, Hans Christian; Eriksen, Paul

    2010-01-01

    The published UV index refers to the expected UV intensity at mid day, when the solar elevation is at its maximum. In Scandinavia, the maximum UV index is seven around midsummer. When the UV index is three, the erythema-weighted dose will be three Standard Erythema Dose (SED) in the hour with max...... a sunburn already when the UV index is higher than two....

  6. Identification of hepatic metabolites of two highly carcinogenic polycyclic aza-aromatic compounds, 7,9-dimethylbenz[c]acridine and 7,10-dimethylbenz[c]acridine.

    Science.gov (United States)

    Ye, Y; Duke, C C; Holder, G M

    1995-03-01

    The hepatic microsomal metabolites of the highly carcinogenic dimethylbenzacridines, 7,9-dimethylbenz[c]acridine (7,9-DMBAC), and 7,10-dimethylbenz[c]acridine (7,10-DMBAC) were obtained with preparations from 3-methylcholanthrene-pretreated rats. Metabolites were separated by reversed-phase HPLC and characterized using UV spectral data and chemical ionization-mass spectrometry after trimethylsilylation and GC. Comparisons with products formed in the presence of the epoxide hydrolase inhibitor, 1,1,1-trichloropropane 2,3-oxide and with those formed from the three synthetic alcohol derivatives of each parent compound, aided the assignment of firm or tentative structures to 16 products from 7,9-DMBAC found in 22 reversed-phase chromatographic peaks, and for 17 products of 7,10-DMBAC found in 19 chromatographic peaks. The more abundant metabolites were derived from oxidation of the methyl groups. Other metabolites were dihydrodiols, epoxides, phenols and secondary metabolites. The 9-methyl group prevented dihydrodiol formation at the 8,9-position from 7,9-DMBAC, and for each carcinogen, the 3,4-dihydrodiol was formed. As well, 3,4-dihydrodiols of methyl oxidized compounds were found.

  7. 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

  8. 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...

  9. A review of biosensing techniques for detection of trace carcinogen contamination in food products.

    Science.gov (United States)

    Li, Zhanming; Yu, Yue; Li, Zhiliang; Wu, Tao

    2015-04-01

    Carcinogen contaminations in the food chain, for example heavy metal ions, pesticides, acrylamide, and mycotoxins, have caused serious health problems. A major objective of food-safety research is the identification and prevention of exposure to these carcinogens, because of their impossible-to-reverse tumorigenic effects. However, carcinogen detection is difficult because of their trace-level presence in food. Thus, reliable and accurate separation and determination methods are essential to protect food safety and human health. This paper summarizes the state of the art in separation and determination methods for analyzing carcinogen contamination, especially the advances in biosensing methods. Furthermore, the application of promising technology including nanomaterials, imprinted polymers, and microdevices is detailed. Challenges and perspectives are also discussed.

  10. OSHA Confronts Carcinogens in the Workplace as Inflation Fighters Confront OSHA.

    Science.gov (United States)

    Heller, Ilene

    1978-01-01

    Discusses the apparently opposing forces of worker safety, as represented by the Occupational Safety and Health Administration (OSHA), and economic inflation spawned by expensive industrial processes needed to limit the emission of carcinogens. (CP)

  11. Carcinogenicity and Immnotoxicity of Embedded Depleted Uranium and Heavy-Metal Tungsten Alloy in Rodents

    National Research Council Canada - National Science Library

    Miller, Alexandra

    2002-01-01

    .... We hypothesize that long-term chronic exposure to embedded DU and HMTA initiates changes in normal immune function that will eventually result in a carcinogenic response characterized by both tumor...

  12. Predictive Models for Carcinogenicity and Mutagenicity: Frameworks,State-of-the-Art, and Perspectives

    Science.gov (United States)

    Mutagenicity and carcinogenicity are endpoints of major environmental and regulatory concern. These endpoints are also important targets for development of alternative methods for screening and prediction due to the large number of chemicals of potential concern and the tremendou...

  13. UV-hardening of coating materials on the basis of unsaturated polyesters

    International Nuclear Information System (INIS)

    Patheiger, M.; Fuhr, K.

    1975-01-01

    The UV-hardening of coated materials based on unsaturated polyester resins is successful in practice. Resins, modified by acrylic acid, are gaining importance for thin coating from paper coatings up to printing colours. A report is given on the binding classes which come into question as photo initiators and whose ways of reaction with UV-irradiation are so far known. The photopolymerizeable coating systems can be used from undercoats to coating varnishes and from thick layers (polishing varnishes) to thinnest layers (printing colours). The economical significance of the UV-process today is illustrated by statistics on the use of binding agents and coating materials. (orig./AK) [de

  14. Quantitative structure activity relationship for the computational prediction of nitrocompounds carcinogenicity

    International Nuclear Information System (INIS)

    Morales, Aliuska Helguera; Perez, Miguel Angel Cabrera; Combes, Robert D.; Gonzalez, Maykel Perez

    2006-01-01

    Several nitrocompounds have been screened for carcinogenicity in rodents, but this is a lengthy and expensive process, taking two years and typically costing 2.5 million dollars, and uses large numbers of animals. There is, therefore, much impetus to develop suitable alternative methods. One possible way of predicting carcinogenicity is to use quantitative structure-activity relationships (QSARs). QSARs have been widely utilized for toxicity testing, thereby contributing to a reduction in the need for experimental animals. This paper describes the results of applying a TOPological substructural molecular design (TOPS-MODE) approach for predicting the rodent carcinogenicity of nitrocompounds. The model described 79.10% of the experimental variance, with a standard deviation of 0.424. The predictive power of the model was validated by leave-one-out validation, with a determination coefficient of 0.666. In addition, this approach enabled the contribution of different fragments to carcinogenic potency to be assessed, thereby making the relationships between structure and carcinogenicity to be transparent. It was found that the carcinogenic activity of the chemicals analysed was increased by the presence of a primary amine group bonded to the aromatic ring, a manner that was proportional to the ring aromaticity. The nitro group bonded to an aromatic carbon atom is a more important determinant of carcinogenicity than the nitro group bonded to an aliphatic carbon. Finally, the TOPS-MODE approach was compared with four other predictive models, but none of these could explain more than 66% of the variance in the carcinogenic potency with the same number of variables

  15. Gene discovery for the carcinogenic human liver fluke, Opisthorchis viverrini

    Directory of Open Access Journals (Sweden)

    Gasser Robin B

    2007-06-01

    Full Text Available Abstract Background Cholangiocarcinoma (CCA – cancer of the bile ducts – is associated with chronic infection with the liver fluke, Opisthorchis viverrini. Despite being the only eukaryote that is designated as a 'class I carcinogen' by the International Agency for Research on Cancer, little is known about its genome. Results Approximately 5,000 randomly selected cDNAs from the adult stage of O. viverrini were characterized and accounted for 1,932 contigs, representing ~14% of the entire transcriptome, and, presently, the largest sequence dataset for any species of liver fluke. Twenty percent of contigs were assigned GO classifications. Abundantly represented protein families included those involved in physiological functions that are essential to parasitism, such as anaerobic respiration, reproduction, detoxification, surface maintenance and feeding. GO assignments were well conserved in relation to other parasitic flukes, however, some categories were over-represented in O. viverrini, such as structural and motor proteins. An assessment of evolutionary relationships showed that O. viverrini was more similar to other parasitic (Clonorchis sinensis and Schistosoma japonicum than to free-living (Schmidtea mediterranea flatworms, and 105 sequences had close homologues in both parasitic species but not in S. mediterranea. A total of 164 O. viverrini contigs contained ORFs with signal sequences, many of which were platyhelminth-specific. Examples of convergent evolution between host and parasite secreted/membrane proteins were identified as were homologues of vaccine antigens from other helminths. Finally, ORFs representing secreted proteins with known roles in tumorigenesis were identified, and these might play roles in the pathogenesis of O. viverrini-induced CCA. Conclusion This gene discovery effort for O. viverrini should expedite molecular studies of cholangiocarcinogenesis and accelerate research focused on developing new interventions

  16. Non-carcinogenic late effects of ionizing radiation; human data

    International Nuclear Information System (INIS)

    Beebe, G.W.

    1979-01-01

    The late effects of ionizing radiation may be somatic effect or potential effect, about which such informations as follows are required: teratogenesis the disturbances in growth and development, cataracts, infertility, cytogenetic aberration, and accelerated aging. Although much is known about the nature of the malformations produced by ionizing radiation, and about the vulnerability of human embryonal and fetal tissues during various stages of organogenesis, the quantitative information is uncertain and incomplete. The data on A-bomb survivors were flawed by confounding radiation dose with nutritional and other influences caused by the disasters created by war-time bombings. If the effects of radiation are real, they are quite small for the dose below 100 rad (kerma), are confined to the children of pre-pubertal age at the time of exposure, and are of much less consequence for low-LET radiation than for high. Radiation-induced lenticular changes are of graded severity, and as for cataracts, the threshold is in the range from 600 to 1,000 rad of low-LET radiation, and perhaps 75 to 100 rad for fast neutrons; the average latent period is 2 to 7 years. The estimate of the RBE for neutrons is in the range from 2 to 10, and dose-dependent. Ionizing radiation has important effects on fertility only at very high dose. The relationship of the quantitative aspects of the biologic significance of chromosomal aberration in somatic cells to dose may provide an interesting parallel to the carcinogenic effect. For neutrons, the dose-response curve appears to be linear, at least for stable aberration. (Yamashita, S.)

  17. Anticarcinogenic effect of betel leaf extract against tobacco carcinogens.

    Science.gov (United States)

    Padma, P R; Lalitha, V S; Amonkar, A J; Bhide, S V

    1989-06-01

    Epidemiological studies have implicated that betel quid offers some protection to tobacco induced carcinogenesis. Earlier studies in our laboratory have shown betel leaf extract (BLE) to be antimutagenic against standard mutagens and tobacco-specific N'-nitrosamines (TSNA), N'-nitrosonornicotine (NNN) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). In the present study, we have tested the anticarcinogenic effect of BLE using Swiss male mice. Two protocols of study were used to test this effect. In the first protocol, the effect of BLE was tested against the standard carcinogen benzo[a]pyrene (BP) using Wattenberg's stomach tumor model, Cancer Res., 41 (1981) 2820-2823. In this protocol, BLE inhibited the tumorigenicity of BP to a significant extent. In the second protocol, the effect of BLE against the two tobacco-specific nitrosamines, NNN and NNK was studied using long-term studies on Swiss male mice. The nitrosamines were administered on the tongues of the mice, while the BLE was supplied in drinking water. Two doses of NNN (22 mg and 72 mg) and one dose of NNK (22 mg) were used. In this study, it was observed that the number of tumor bearing animals decreased, but the difference was significant only in the group treated with the low dose of NNN in combination with BLE. However, in all the BLE treated animals, irrespective of the dose of nitrosamine, the hepatic vitamin A and C levels were elevated significantly as compared to the corresponding nitrosamine-treated controls. These results indicate that BLE has a promising anticarcinogenic role to play in tobacco induced cancer.(ABSTRACT TRUNCATED AT 250 WORDS)

  18. Feasibility of preventing the effects of carcinogens on man

    Energy Technology Data Exchange (ETDEWEB)

    Shabad, L M; Wittig, K; Khesina, I A

    1973-01-01

    Measures are considered for reducing atmospheric levels of polycyclic aromatic hydrocarbons produced by domestic heating, industry, and motor vehicles. Older home heating systems should be replaced with ones which can burn more efficiently. It is recommended that emissions from industrial sources, such as by-product coke plants, petroleum refineries, and plants producing carbon black, resins, and gas, should be reduced by the use of filters or by more complete combustion. The amount of polycyclic aromatic hydrocarbons in motor vehicle exhaust can be reduced by using oil additives, changing the ratio of gasoline to oil, and using neutralizers, but more appropriate long-term solutions would be to use vehicles powered by gas or electricity. Since the largest amounts of benzyprene (BP) are produced by idling motors, traffic flow should be improved by separating foot and automobile traffic. The amount of BP in airplane emissions has been reduced by more than 30% by adding magnesium to the fuel and by about 60% by using dearomatized fuels. To prevent lung cancer it is necessary to reduce the levels of not only carcinogens and cocarcinogens, but also of toxic substances, e.g., sulfur dioxide, oxides of nitrogen, and acrolein, which reduce ciliary activity in the bronchial epithelium. Since it is impractical to eliminate polycyclic aromatic hydrocarbons from the human environment at present, maximum permissible concentrations of BP have been established in the Soviet Union. They are 0.01 microg/100 m/sup 3/ BP for the atmosphere and 15 microg/100 m/sup 3/ in work places.

  19. 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.

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

    Directory of Open Access Journals (Sweden)

    María Belén Federico

    2016-01-01

    Full Text Available 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.

  1. Influence of pre- and post-treatment with caffeine on UV-induced effects in Oedogonium gunnii Wittr

    International Nuclear Information System (INIS)

    Srivastava, Sudha; Sarma, Y.S.R.K.

    1981-01-01

    Zoospores and mature filaments of O.gunnii were treated with 0.05 and 0.25% of caffeine 2 hr prior and immediately after exposure to UV. While the caffeine treatment given 2 hr prior to UV-exposure lowered the percentage of chromosomal aberrations, the same concentrations of caffeine, when employed immediately after UV-exposure, resulted in an increased frequency of chromosomal aberrations. Caffeine appears to act as protective as well as potentiating agent in relation to UV-induced effects both with respect to survival of zoospores and chromosomal aberrations in mature filaments. (author)

  2. DNA-protein complexes induced by chromate and other carcinogens

    International Nuclear Information System (INIS)

    Costa, M.

    1991-01-01

    DNA-protein complexes induced in intact Chinese hamster ovary cells by chromate have been isolated, analyzed, and compared with those induced by cis-platinum, ultraviolet light, and formaldehyde. Actin has been identified as one of the major proteins complexed to DNA by chromate based upon its molecular weight, isoelectric point, positive reaction with an actin polyclonal antibody, and proteolytic mapping. Chromate and cis-platinum both complex proteins of similar molecular weight and isoelectric point, positive reaction with an actin polyclonal antibody, and proteolytic mapping. Chromate and cis-platinum both complex proteins of similar molecular weight and isoelectric points, and these complexes can be disrupted by chelating agents and sulfhydryl reducing agents, suggesting that the metal itself is participating in binding rather than having a catalytic or indirect role (i.e., oxygen radicals). In contrast, formaldehyde complexed histones to the DNA, and these complexes were not disrupted by chelating or reducing agents. An antiserum raised to chromate-induced DNA-protein complexes reacted primarily with 97,000 kDa protein that did not silver stain. Slot blots, as well as Western blots, were used to detect formation of p97 DNA crosslinks. This protein was complexed to the DNA by all four agents studied

  3. 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.

  4. Carcinogenicity assessments of biotechnology-derived pharmaceuticals: a review of approved molecules and best practice recommendations.

    Science.gov (United States)

    Vahle, John L; Finch, Gregory L; Heidel, Shawn M; Hovland, David N; Ivens, Inge; Parker, Suezanne; Ponce, Rafael A; Sachs, Clifford; Steigerwalt, Ronald; Short, Brian; Todd, Marque D

    2010-06-01

    An important safety consideration for developing new therapeutics is assessing the potential that the therapy will increase the risk of cancer. For biotherapeutics, traditional two-year rodent bioassays are often not scientifically applicable or feasible. This paper is a collaborative effort of industry toxicologists to review past and current practice regarding carcinogenicity assessments of biotherapeutics and to provide recommendations. Publicly available information on eighty marketed protein biotherapeutics was reviewed. In this review, no assessments related to carcinogenicity or tumor growth promotion were identified for fifty-one of the eighty molecules. For the twenty-nine biotherapeutics in which assessments related to carcinogenicity were identified, various experimental approaches were employed. This review also discusses several key principles to aid in the assessment of carcinogenic potential, including (1) careful consideration of mechanism of action to identify theoretical risks, (2) careful investigation of existing data for indications of proliferative or immunosuppressive potential, and (3) characterization of any proliferative or immunosuppressive signals detected. Traditional two-year carcinogenicity assays should not be considered as the default method for assessing the carcinogenicity potential of biotherapeutics. If experimentation is considered warranted, it should be hypothesis driven and may include a variety of experimental models. Ultimately, it is important that preclinical data provide useful guidance in product labeling.

  5. 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.

  6. Dopantless Diodes for Efficient Mid/deep UV LEDs and Lasers - Topic 4.2 Optoelectronics

    Science.gov (United States)

    2017-09-12

    UVB/UVC solid state emitters is a rapidly growing market – UV curing of adhesives – Water disinfection – Chemical Agent detection • Replacement of...recombination • Electron leakage • Junction heating ~3.5× EL in TJ LEDS ~2× EL @ 180 A/cm2 DC measurements; 0.1mm×0.1mm 29 Increased wall plug efficiency 0...market – UV curing of adhesives – Water disinfection – Chemical Agent detection • Replacement of bulky, toxic Hg arc lamps • Applications require high

  7. Carcinogenicity study of 3-monochloropropane-1, 2-diol (3-MCPD) administered by drinking water to B6C3F1 mice showed no carcinogenic potential.

    Science.gov (United States)

    Jeong, Jayoung; Han, Beom Seok; Cho, Wan-Seob; Choi, Mina; Ha, Chang-Su; Lee, Byoung-Seok; Kim, Yong-Bum; Son, Woo-Chan; Kim, Choong-Yong

    2010-09-01

    3-Monochloropropane-1, 2-diol (or 3-chloro-1,2-propanediol, 3-MCPD) is a well-known food processing contaminant found in a wide range of foods and ingredients. It has been classified as non-genotoxic carcinogen but its carcinogenic potential in the rodents has been controversial. The carcinogenicity to B6C3F1 mice by drinking water administration was assessed over a period of 104 weeks. Three groups, each comprising 50 male and 50 female mice received 3-MCPD at dosages of 30, 100 or 300 ppm up to Day 100 and 200 ppm onward (4.2, 14.3 and 33.0 mg/kg for males; 3.7, 12.2, and 31.0 mg/kg for females), were allocated. Survival was good, with at least 80% of males and 72% of females in each group surviving 104 weeks. Body weights and body weight gain were decreased in males and females receiving 200 ppm. Water and food consumptions of both sexes at 300/200 ppm were lowered. Emaciated or crouching position was observed for animals of both sexes exposed to 200 ppm. There were some differences in hematology and serum biochemistry compared with controls, although there was no histopathological evidence to support those changes. Histopathological examination did not reveal any neoplastic or non-neoplastic findings attributable to treatment with 3-MCPD. It is concluded that drinking water administration of 3-MCPD for 104 weeks revealed no evidence of carcinogenic potential.

  8. Comparative statistical analysis of carcinogenic and non-carcinogenic effects of uranium in groundwater samples from different regions of Punjab, India

    International Nuclear Information System (INIS)

    Saini, Komal; Singh, Parminder; Bajwa, Bikramjit Singh

    2016-01-01

    LED flourimeter has been used for microanalysis of uranium concentration in groundwater samples collected from six districts of South West (SW), West (W) and North East (NE) Punjab, India. Average value of uranium content in water samples of SW Punjab is observed to be higher than WHO, USEPA recommended safe limit of 30 µg l −1 as well as AERB proposed limit of 60 µg l −1 . Whereas, for W and NE region of Punjab, average level of uranium concentration was within AERB recommended limit of 60 µg l −1 . Average value observed in SW Punjab is around 3–4 times the value observed in W Punjab, whereas its value is more than 17 times the average value observed in NE region of Punjab. Statistical analysis of carcinogenic as well as non carcinogenic risks due to uranium have been evaluated for each studied district. - Highlights: • Uranium level in groundwater samples have been assessed in different regions of Punjab. • Comparative study of carcinogenic and non carcinogenic effects of uranium has been done. • Wide variation has been found for different geological regions. • It has been found that South west Punjab is worst affected by uranium contamination in its water. • For west and north east regions of Punjab, uranium levels in groundwater laid under recommended safe limits.

  9. 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

  10. Near UV Aerosol Group Report

    Science.gov (United States)

    Torres, Omar

    2013-01-01

    2012-13 Report of research on aerosol and cloud remote sensing using UV observations. The document was presented at the 2013 AEROCENTER Annual Meeting held at the GSFC Visitors Center, May 31, 2013. The Organizers of the meeting are posting the talks to the public Aerocentr website, after the meeting.

  11. UV-induced DNA-binding proteins in human cells

    International Nuclear Information System (INIS)

    Glazer, P.M.; Greggio, N.A.; Metherall, J.E.; Summers, W.C.

    1989-01-01

    To investigate the response of human cells to DNA-damaging agents such as UV irradiation, the authors examined nuclear protein extracts of UV-irradiated HeLa cells for the presence of DNA-binding proteins. Electrophoretically separated proteins were transferred to a nitrocellulose filter that was subsequently immersed in a binding solution containing radioactively labeled DNA probes. Several DNA-binding proteins were induced in HeLa cells after UV irradiation. These included proteins that bind predominantly double-stranded DNA and proteins that bind both double-stranded and single-stranded DNA. The binding proteins were induced in a dose-dependent manner by UV light. Following a dose of 12 J/m 2 , the binding proteins in the nuclear extracts increased over time to a peak in the range of 18 hr after irradiation. Experiments with metabolic inhibitors (cycloheximide and actinomycin D) revealed that de novo synthesis of these proteins is not required for induction of the binding activities, suggesting that the induction is mediated by protein modification

  12. 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.

  13. Poling of UV-written Waveguides

    DEFF Research Database (Denmark)

    Arentoft, Jesper; Kristensen, Martin; Hübner, Jörg

    1999-01-01

    We report poling of UV-written silica waveguides. Thermal poling induces an electro-optic coefficient of 0.05 pm/V. We also demonstrate simultaneous UV-writing and UV-poling. No measurable decay in the induced electro-optic effect was detected after nine months......We report poling of UV-written silica waveguides. Thermal poling induces an electro-optic coefficient of 0.05 pm/V. We also demonstrate simultaneous UV-writing and UV-poling. No measurable decay in the induced electro-optic effect was detected after nine months...

  14. Photoprotectant improves photostability and bioactivity of abscisic acid under UV radiation.

    Science.gov (United States)

    Gao, Fei; Hu, Tanglu; Tan, Weiming; Yu, Chunxin; Li, Zhaohu; Zhang, Lizhen; Duan, Liusheng

    2016-05-01

    Photosensitivity causes serious drawback for abscisic acid (ABA) application, but preferable methods to stabilize the compound were not found yet. To select an efficient photoprotectant for the improvement of photostability and bioactivity of ABA when exposed to UV light, we tested the effects of a photostabilizer bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate (HS-770) and two UV absorbers 2-hydroxy-4-n-octoxy-benzophenone (UV-531) and 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid (BP-4) with or without HS-770 on the photodegradation of ABA. Water soluble UV absorber BP-4 and oil soluble UV absorber UV-531 showed significant photo-stabilizing capability on ABA, possibly due to competitive energy absorption of UVB by the UV absorbers. The two absorbers showed no significant difference. Photostabilizer HS-770 accelerated the photodegradation of ABA and did not improve the photo-stabilizing capability of BP-4, likely due to no absorption in UVB region and salt formation with ABA and BP-4. Approximately 26% more ABA was kept when 280mg/l ABA aqueous solution was irradiated by UV light for 2h in the presence of 200mg/l BP-4. What's more, its left bioactivity on wheat seed (JIMAI 22) germination was greatly kept by BP-4, comparing to that of ABA alone. The 300 times diluent of 280mg/l ABA plus 200mg/l BP-4 after 2h irradiation showed more than 13% inhibition on shoot and root growth of wheat seed than that of ABA diluent alone. We concluded that water soluble UV absorber BP-4 was an efficient agent to keep ABA activity under UV radiation. The results could be used to produce photostable products of ABA compound or other water soluble agrichemicals which are sensitive to UV radiation. The frequencies and amounts of the agrichemicals application could be thereafter reduced. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. 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. © 2014 Wiley Periodicals, Inc.

  16. Development of quantitative structure-activity relationship (QSAR) models to predict the carcinogenic potency of chemicals

    International Nuclear Information System (INIS)

    Venkatapathy, Raghuraman; Wang Chingyi; Bruce, Robert Mark; Moudgal, Chandrika

    2009-01-01

    Determining the carcinogenicity and carcinogenic potency of new chemicals is both a labor-intensive and time-consuming process. In order to expedite the screening process, there is a need to identify alternative toxicity measures that may be used as surrogates for carcinogenic potency. Alternative toxicity measures for carcinogenic potency currently being used in the literature include lethal dose (dose that kills 50% of a study population [LD 50 ]), lowest-observed-adverse-effect-level (LOAEL) and maximum tolerated dose (MTD). The purpose of this study was to investigate the correlation between tumor dose (TD 50 ) and three alternative toxicity measures as an estimator of carcinogenic potency. A second aim of this study was to develop a Classification and Regression Tree (CART) between TD 50 and estimated/experimental predictor variables to predict the carcinogenic potency of new chemicals. Rat TD 50 s of 590 structurally diverse chemicals were obtained from the Cancer Potency Database, and the three alternative toxicity measures considered in this study were estimated using TOPKAT, a toxicity estimation software. Though poor correlations were obtained between carcinogenic potency and the three alternative toxicity (both experimental and TOPKAT) measures for the CPDB chemicals, a CART developed using experimental data with no missing values as predictor variables provided reasonable estimates of TD 50 for nine chemicals that were part of an external validation set. However, if experimental values for the three alternative measures, mutagenicity and logP are not available in the literature, then either the CART developed using missing experimental values or estimated values may be used for making a prediction

  17. Changes in UV absorption of sunscreens after UV irradiation

    Science.gov (United States)

    Tarras-Wahlberg, N.; Stenhagen, G.; Larkö, O.; Rosén, A.; Wennberg, A.-M.; Wennerström, O.

    2000-03-01

    In the present investigation we have studied the change in the absorption spectrum of some photoactive organic species in sunscreens after UVA and UVB irradiation in a dose normally encountered during a full day in the sun. The absorbance of 2-ethylhexyl 4-methoxycinnamate was reduced significantly, while 3-(4-methylbenzyliden)camphor seemed to be rather stable. The benzophenones studied seemed to be relatively stable. In the case of 4-tert.butyl-4´-methoxy-dibenzoylmethane there was a rapid decrease in the UVA absorption leading to unsatisfactory protection in the UVA region. 4-Isopropyl-dibenzoylmethane also lost most of its UV protective capacity after irradiation with UVA. UVB seemed to have a minor effect on all the samples. The present study including gas chromatography and mass spectrometry analysis indicates that some of the photoactive organic species commonly used today in sunscreens are unstable following UV irradiation.

  18. UV and vacuum-UV biological spectroscopy using synchrotron radiation

    International Nuclear Information System (INIS)

    Ito, Amando Siuiti

    1996-01-01

    Full text. Synchrotron radiation has been used as light source in the UV and VUV region for the study of many biological systems. In the time domain, measurements are made that allow the observation of dynamics and kinetics of biomolecules like proteins and peptides, using the fluorescent properties of either intrinsic or extrinsic probes. Optical activity of groups inside biomolecules allows the use of circular dichroism techniques to generate structural information and to follow processes like protein folding. Confocal scanning of synchrotron light generates microscopy resolution below 100 nm, allowing the creation of high quality three dimensional images of biological samples, and the collection of fluorescence originated from microvolumes inside the samples. We propose a station at LNLS for these three techniques: time-resolved fluorescence, circular dischroism and confocal microscopy, using UV and VUV light. (author)

  19. Fundamental Questions in Astrophysics: Guidelines for Future UV Observatories

    CERN Document Server

    Gómez de Castro, Ana I

    2006-01-01

    Modern astrophysics is a mature science that has evolved from its early phase of discovery and classification to a physics-oriented discipline focused in finding answers to fundamental problems ranging from cosmology to the origin and diversity of life-sustainable systems in the Universe. For this very reason, progress of modern astrophysics requires the access to the electromagnetic spectrum in the broadest energy range. The Ultraviolet is a fundamental energy domain since it is one of the most powerful tool to study plasmas at temperatures in the 3,000-300,000~K range as well as electronic transitions of the most abundant molecules in the Universe. Moreover, the UV radiation field is a powerful astrochemical and photoionizing agent. This book describes the fundamental problems in modern astrophysics that cannot progress without easy and wide-spread access to modern UV instrumentation.

  20. 207-nm UV Light-A Promising Tool for Safe Low-Cost Reduction of Surgical Site Infections. II: In-Vivo Safety Studies.

    Science.gov (United States)

    Buonanno, Manuela; Stanislauskas, Milda; Ponnaiya, Brian; Bigelow, Alan W; Randers-Pehrson, Gerhard; Xu, Yanping; Shuryak, Igor; Smilenov, Lubomir; Owens, David M; Brenner, David J

    2016-01-01

    UVC light generated by conventional germicidal lamps is a well-established anti-microbial modality, effective against both bacteria and viruses. However, it is a human health hazard, being both carcinogenic and cataractogenic. Earlier studies showed that single-wavelength far-UVC light (207 nm) generated by excimer lamps kills bacteria without apparent harm to human skin tissue in vitro. The biophysical explanation is that, due to its extremely short range in biological material, 207 nm UV light cannot penetrate the human stratum corneum (the outer dead-cell skin layer, thickness 5-20 μm) nor even the cytoplasm of individual human cells. By contrast, 207 nm UV light can penetrate bacteria and viruses because these cells are physically much smaller. To test the biophysically-based hypothesis that 207 nm UV light is not cytotoxic to exposed mammalian skin in vivo. Hairless mice were exposed to a bactericidal UV fluence of 157 mJ/cm2 delivered by a filtered Kr-Br excimer lamp producing monoenergetic 207-nm UV light, or delivered by a conventional 254-nm UV germicidal lamp. Sham irradiations constituted the negative control. Eight relevant cellular and molecular damage endpoints including epidermal hyperplasia, pre-mutagenic UV-associated DNA lesions, skin inflammation, and normal cell proliferation and differentiation were evaluated in mice dorsal skin harvested 48 h after UV exposure. While conventional germicidal UV (254 nm) exposure produced significant effects for all the studied skin damage endpoints, the same fluence of 207 nm UV light produced results that were not statistically distinguishable from the zero exposure controls. As predicted by biophysical considerations and in agreement with earlier in vitro studies, 207-nm light does not appear to be significantly cytotoxic to mouse skin. These results suggest that excimer-based far-UVC light could potentially be used for its anti-microbial properties, but without the associated hazards to skin of conventional

  1. UV spectrophotometry of the Metronidazole

    Directory of Open Access Journals (Sweden)

    O. I. Panasenko

    2013-10-01

    Full Text Available Objective. The purpose of this research was to study the UV spectrum of Metronidazole in different polarity solvents (water, 95 % ethanol, 0,1 M sodium hydroxide, 0,1 M hydrochloric acid and 5 M sulfuric acid solution, to establish the relationship between chemical structure of the analyzed compounds and the nature of their electronic spectrum. In addition, a detailed study of the ultraviolet spectra of Metronidazole in different solutions enables to select the optimal wavelength and a thinner design for Metronidazole in substance and dosage forms. Materials and methods. Spectrophotometer SPECORD 200-222U214 has been used for study of the UV spectra of Metronidazole, the quantitative methods were used. Measuring of the absorption of Metronidazole solutions has been carried out in quartz cuvettes with a layer thickness of 10 mm. Due to the fact that the test material shows selective absorption in the ultraviolet spectra, model compounds were studied at a concentration of 1 mg%. Study of electronic spectra was performed in the range of 200 to 400 nm, and the curve has been constructed in coordinates A = f (λ. It has been used water, 95% ethanol, 0,1 M NaOH, 0,1 M HCl and 5 M H2SO4 as solvents. The content of Metronidazole in substance and dosage forms calculated with the equations according to SPU. The results. Study of the UV spectra of Metronidazole and its model compounds showed that in short-wave part of spectrum due to absorption and excitation electrons of imidazole ring were transferred, and in long-wave – conjugation chromophore imidazole cycle and nitro group as electron acceptor occurred. Analysis of the UV spectra of Metronidazole enables to determine a maximum of the analytical quantification of the medicine. Conclusions. Metronidazole UV spectra in water, 95% ethanol, 0,1 M solution of NaOH, 0,1 M solution of HCl and 5 M solution of H2SO4 have been studied. Metronidazole UV spectra are characterized by two absorption bands in the

  2. UV DISINFECTION GUIDANCE MANUAL FOR THE ...

    Science.gov (United States)

    Provides technical information on selection, design and operation of UV systems; provides regulatory agencies with guidance and the necessary tools to assess UV systems at the design, start-up, and routine operation phase; provides manufacturers with the testing and performance standards for UV components and systems for treating drinking water. Provide guidance to water systems, regulators and manufacturers on UV disinfection of drinking water.

  3. It is time to regulate carcinogenic tobacco-specific nitrosamines in cigarette tobacco

    Science.gov (United States)

    Hecht, Stephen S.

    2014-01-01

    The Family Smoking Prevention and Tobacco Control Act gives the Food and Drug Administration power to regulate tobacco products. This commentary calls for immediate regulation of the carcinogenic tobacco-specific nitrosamines 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and N’-nitrosonornicotine (NNN) in cigarette tobacco as a logical path to cancer prevention. NNK and NNN, powerful carcinogens in laboratory animals, have been evaluated as “carcinogenic to humans” by the International Agency for Research on Cancer. NNK and NNN are present in the tobacco of virtually all marketed cigarettes; levels in cigarette smoke are directly proportional to the amounts in tobacco. The NNK metabolite NNAL, itself a strong carcinogen, is present in the urine of smokers and non-smokers exposed to secondhand smoke. Some of the highest levels of NNK and NNN are found in U.S. products. It is well established that factors such as choice of tobacco blend, agricultural conditions, and processing methods influence levels of NNK and NNN in cigarette tobacco and cigarette smoke. Therefore, it is time to control these factors and produce cigarettes with 100 ppb or less each of NNK and NNN in tobacco, which would result in an approximate 15-20 fold reduction of these carcinogens in the mainstream smoke of popular cigarettes sold in the United States. PMID:24806664

  4. Non-genotoxic carcinogens: early effects on gap junctions, cell proliferation and apoptosis in the rat

    International Nuclear Information System (INIS)

    Mally, Angela; Chipman, James Kevin

    2002-01-01

    Non-genotoxic carcinogens are thought to induce tumour formation by disturbing the balance between cell growth and cell death. Gap junctions (GJ) contribute to the maintenance of tissue homeostasis by allowing the intercellular exchange of growth regulatory signals and potential inhibition of GJ intercellular communication through loss of connexin (Cx) plaques has been shown to be involved in the cancer process. We have investigated the time- and dose-dependent effects of the non-genotoxic hepatocarcinogens Wy-14,643, 2,3,7,8-tetrachlorodibenzo-p-dioxin, methapyrilene and hexachlorobenzene and the male rat kidney carcinogens chloroform, p-dichlorobenzene and d-limonene on gap junction plaque expression in relation to proliferation and apoptosis. With the exception of limonene, all non-genotoxic carcinogens significantly reduced the expression of GJ plaques containing Cx32 in their respective target tissue. No dose-dependent, significant effects were seen in non-target organs. Although alteration of Cx32 expression did not appear to correlate with induction of cell proliferation, out data suggest that the interaction of both processes--interference of GJ coupled with a proliferative stimulus (at the carcinogenic dose)--may be important in non-genotoxic carcinogenesis and provide a potential alert for non-genotoxic carcinogens in short-term toxicity tests

  5. Capturing Labile Sulfenamide and Sulfinamide Serum Albumin Adducts of Carcinogenic Arylamines by Chemical Oxidation

    Science.gov (United States)

    Peng, Lijuan; Turesky, Robert J.

    2013-01-01

    Aromatic amines and heterocyclic aromatic amines (HAAs) are a class of structurally related carcinogens that are formed during the combustion of tobacco or during the high temperature cooking of meats. These procarcinogens undergo metabolic activation by N-oxidation of the exocyclic amine group to produce N-hydroxylated metabolites, which are critical intermediates implicated in toxicity and DNA damage. The arylhydroxylamines and their oxidized arylnitroso derivatives can also react with cysteine (Cys) residues of glutathione or proteins to form, respectively, sulfenamide and sulfinamide adducts. However, sulfur-nitrogen linked adducted proteins are often difficult to detect because they are unstable and undergo hydrolysis during proteolytic digestion. Synthetic N-oxidized intermediates of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), a carcinogenic HAA produced in cooked meats, and 4-aminobiphenyl, a carcinogenic aromatic amine present in tobacco smoke were reacted with human serum albumin (SA) and formed labile sulfenamide or sulfinamide adducts at the Cys34 residue. Oxidation of the carcinogen-modified SA with m-chloroperoxybenzoic acid (m-CPBA) produced the arylsulfonamide adducts, which were stable to heat and the chemical reduction conditions employed to denature SA. The sulfonamide adducts of PhIP and 4-ABP were identified, by liquid chromatography/mass spectrometry, in proteolytic digests of denatured SA. Thus, selective oxidation of arylamine-modified SA produces stable arylsulfonamide-SA adducts, which may serve as biomarkers of these tobacco and dietary carcinogens. PMID:23240913

  6. Nitric oxide: cancer target or anticancer agent?

    Science.gov (United States)

    Mocellin, Simone

    2009-03-01

    Despite the improved understanding of nitric oxide (NO) biology and the large amount of preclinical experiments testing its role in cancer development and progression, it is still debated whether NO should be considered a potential anticancer agent or instead a carcinogen. The complexity of NO effects within a cell and the variability of the final biological outcome depending upon NO levels makes it highly challenging to determine the therapeutic value of interfering with the activity of this intriguing gaseous messenger. This uncertainty has so far halted the clinical implementation of NO-based therapeutics in the field of oncology. Accordingly, only an in depth knowledge of the mechanisms leading to experimental tumor regression or progression in response to NO will allow us to exploit this molecule to fight cancer.

  7. UV Tanning Equipment | Radiation Protection | US EPA

    Science.gov (United States)

    2017-08-07

    Sun lamps and tanning equipment emit ultraviolet (UV) rays. People who are exposed to UV rays over a long period of time are more likely to develop skin cancer. People with light skin are in more danger because their skin is more sensitive to UV rays.

  8. 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

  9. 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%).

  10. Effects of alkylating carcinogens on human tumor cells in culture

    International Nuclear Information System (INIS)

    Goth-Goldstein, R.; Hughes, M.

    1987-01-01

    In Escherichia coli 3-methyladenine and 3-methylguanine have been identified as lethal lesions, since two types of alkylating agent-sensitive mutants were deficient in repair of either of these lesions. Similar alkylation-sensitive human cell lines exist. These are the tumor cell lines of the complex Mer - phenotype. All Mer - cells examined were hypersensitive to killing by MNNG and other alkylating agents, and failed to repair O 6 -methylguanine. The widely studied HeLa S3 cell line has the Mer + phenotype, but a Mer - variant (HeLa MR) has arisen. This offers the possibility to study Mer - and Mer + cells of otherwise similar genetic background. We are using these two variants to analyze the Mer - phenotype further. When HeLa S3 and HeLa MR were treated with a highly dose of MNNG, and the surviving population exposed to a second dose of MNNG 2-3 weeks later, HeLa S3 (Mer + ) cells were equally or even slightly more sensitive to a second exposure of MNNG, whereas the surviving HeLa MR (Mer - ) population was much more resistant to MNNG. 1 fig., 1 tab

  11. Interacting agents in finance

    NARCIS (Netherlands)

    Hommes, C.; Durlauf, S.N.; Blume, L.E.

    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

  12. Riot Control Agents

    Science.gov (United States)

    ... Submit What's this? Submit Button Facts About Riot Control Agents Interim document Recommend on Facebook Tweet Share Compartir What riot control agents are Riot control agents (sometimes referred to ...

  13. Effect of chemical peeling on the skin in relation to UV irradiation.

    Science.gov (United States)

    Funasaka, Yoko; Abdel-Daim, Mohamed; Kawana, Seiji; Nishigori, Chikako

    2012-07-01

    Chemical peeling is one of the dermatological treatments available for certain cutaneous diseases and conditions or improvement of cosmetic appearance of photoaged skin. However, it needs to be clarified whether the repetitive procedure of chemical peeling on photodamaged skin is safe and whether the different chemicals used for peeling results in similar outcomes or not. In this article, we reviewed the effect of peeling or peeling agents on the skin in relation to ultraviolet (UV) radiation. The pretreatment of peeling agents usually enhance UV sensitivity by inducing increased sunburn cell formation, lowering minimum erythematous dose and increasing cyclobutane pyrimidine dimers. However, this sensitivity is reversible and recovers to normal after 1-week discontinuation. Using animals, the chronic effect of peeling and peeling agents was shown to prevent photocarcinogenesis. There is also an in vitro study using culture cells to know the detailed mechanisms of peeling agents, especially on cell proliferation and apoptotic changes via activating signalling cascades and oxidative stress. It is important to understand the effect of peeling agents on photoaged skin and to know how to deal with UV irradiation during the application of peeling agents and treatment of chemical peeling in daily life. © 2012 John Wiley & Sons A/S.

  14. 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

  15. Role of chemical carcinogens in epithelial and mesenchymal neoplasms with tumor initiation-promotion protocol and the effect of 13-cis retinoic acid in chemo prevention

    International Nuclear Information System (INIS)

    Bukhari, S.M.H.; Shahzad, S.Q.; Naeem, S.; Qureshi, G.R.; Naveed, I.A.

    2002-01-01

    Objective: To study the effects of chemical carcinogens on epithelial and mesenchymal tumorigenesis with tumor initiation-promotion protocol and the use of 13-cis retinoic acid as a chemo preventive agent. Design: It was an experimental study. Place and Duration of Study: The study was conducted at Postgraduate Medical Institute (PGML) Lahore for 20 weeks. Materials and Methods: Sixty albino rats were divided into six groups of ten of animals each. First group of animals (control) was not given carcinogens and 13-cis retinoic acid in second group DMBA was applied on the dorsal skin in repeated dos of 100 mu g/ml in acetone, twice a weak. In the third group DMBA was given 100 mu g/ml as single dose while TPA was given 10 mu g//ml in acetone, twice a weak after two weeks of DMBA applications. In fourth group only DMBA 100 mu g/ml in acetone was applied as a single dose. In fifth and sixth groups 13-cis retinoic acid was given topically before and after the application of DMBA and TPA. Results: First and fourth groups did not develop any tumor. In second groups 2 animals developed malignant fibrous histiocytoma, 4 squamous cell carcinoma while 1 dysphasia and 1 carcinoma in situ. Third group developed osteoma (3 animals), papilloma (3 animals, squamous cell carcinoma (01) and dysplasia (01). Conclusion: Our results showed that DMBA acts as tumor initiator while TPA as promoter. DMBA also produces tumors itself when given alone in repeated doses. The chemical carcinogens are not only a cause of epithelial carcinogenesis but also responsible for mesenchymal tumorigenesis. 13 cis retinoic acid was equally effective in both stages of tumorigenesis. It also prevents malignant conversion of chemically induced benign tumors. (author)

  16. UV-cured polymer optics

    Science.gov (United States)

    Piñón, Victor; Santiago, Freddie; Vogelsberg, Ashten; Davenport, Amelia; Cramer, Neil

    2017-10-01

    Although many optical-quality glass materials are available for use in optical systems, the range of polymeric materials is limited. Polymeric materials have some advantages over glass when it comes to large-scale manufacturing and production. In smaller scale systems, they offer a reduction in weight when compared to glass counterparts. This is especially important when designing optical systems meant to be carried by hand. We aimed to expand the availability of polymeric materials by exploring both crown-like and flint-like polymers. In addition, rapid and facile production was also a goal. By using UV-cured thiolene-based polymers, we were able to produce optical materials within seconds. This enabled the rapid screening of a variety of polymers from which we down-selected to produce optical flats and lenses. We will discuss problems with production and mitigation strategies in using UV-cured polymers for optical components. Using UV-cured polymers present a different set of problems than traditional injection-molded polymers, and these issues are discussed in detail. Using these produced optics, we integrated them into a modified direct view optical system, with the end goal being the development of drop-in replacements for glass components. This optical production strategy shows promise for use in lab-scale systems, where low-cost methods and flexibility are of paramount importance.

  17. 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. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Efecto de la exposición a la luz ultravioleta uv-c en la viabilidad de especies de Eschericha coli y Salmonella typhimurium

    OpenAIRE

    Oviedo, Dumas; Rojas, Jesús María; Borda, Ricardo Alberto; Durango, Mónica María

    2013-01-01

    Introduction. The germicidal effect UV-C light has is regarded as an effective tool to inactivate and eliminate harmful contaminating agents, such as Escherichia coli and Salmonella typhimurium. Objective. evaluating the effectiveness of UV-C light for reducing Escherichia coli and Salmonella typhimorium populations from cultures that had the microorganisms, combining factors like concentration, time and distance. Methodology. A UV-C lamp, with a 254 nm and 8 ...

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

    International Nuclear Information System (INIS)

    Huberman, E.; Langenbach, R.

    1977-01-01

    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

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

    International Nuclear Information System (INIS)

    Anisimov, V.N.

    1983-01-01

    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)

  1. [Cardiovascular risk, occupation and exposure to occupational carcinogens in a group of workers in Salamanca].

    Science.gov (United States)

    González-Sánchez, Jesús

    2015-01-01

    Identify the cardiovascular risk factors in a group of workers in the province of Salamanca, protected by external prevention services, as regards exposure to occupational carcinogens, by sector of activity and gender. An observational descriptive epidemiological study was conducted. The sample selection was by stratified random sampling in each entity. The variables collected by questionnaire were, sociodemographic characteristics, exposure to occupational carcinogens, and cardiovascular risk factors (smoking, hypertension, dyslipidemia, and diabetes), using the clinical-work histories as a source of information. Statistically significant differences were observed in cardiovascular risk according to the exposure to occupational carcinogens (p cardiovascular risk in the work place. Copyright © 2014 Elsevier España, S.L.U. All rights reserved.

  2. Policy issues in setting de minimis standards for latent cancer risks of radiation and chemical carcinogens

    International Nuclear Information System (INIS)

    Spangler, M.

    1984-01-01

    In the fuel cycles for the development and utilization of alternative energy resources, the risk of latent cancer arises from a number of sources. Included are ionizing radiation and the carcinogenic potential of polluting chemicals present in certain fuels or in materials associated with the construction, operation, maintenance or waste treatment processes of nuclear power, fossil fuels, synfuels, biomass, and other sources of energy. One aspect of developing a carcinogen guideline policy for a consistent and effective regulatory regime to use in dealing with these assorted carcinogenic risks is the setting of de minimis quantitative standards. In this report, 11 policy issues related to the setting of such regulatory standards are identified and a brief commentary is provided. 15 references, 1 table

  3. The carcinogenicity of 1-methyl-3(p-bromophenyl)-1-nitrosourea (Br-MPNU).

    Science.gov (United States)

    Warzok, R; Martin, J; Mendel, J; Thust, R; Schwarz, H

    1983-01-01

    In long-term experiments with Hooded rats the carcinogenic potential of 1-methyl-3(p-bromophenyl)-1-nitrosourea (Br-MPNU) could be demonstrated for the first time. Br-MPNU is formed also endogenously after combined administration of 1-methyl-3(p-bromophenyl)-urea (Br-MPU) and sodium nitrite. After repeated intragastric administration of 0.33 mmol Br-MPU and 0.73 mmol NaNO2 per kg b.w. papillomas and carcinomas of the forestomach developed in 83%. After repeated administration of 0.28 mmol Br-MPNU per kg b.w. these neoplasms were observed in 88%. The comparison of results obtained in similar experiments with 1-methyl-3-phenyl-1-nitrosourea shows that bromine substitution led to a reduction of the carcinogenic activity. The present paper is part of a complex program studying the interrelationships between structure, physico-chemical properties, mutagenicity and carcinogenicity of nitrosoureas.

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

    International Nuclear Information System (INIS)

    Woloschak, G.E.; Panozzo, J.; Libertin, C.R.; Schreck, S.; South Carolina Univ., Columbia, SC

    1994-01-01

    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

  5. The effects of near-UV radiation on elasmobranch lens cytoskeletal actin.

    Science.gov (United States)

    Zigman, S; Rafferty, N S; Scholz, D L; Lowe, K

    1992-08-01

    The role of near-UV radiation as a cytoskeletal actin-damaging agent was investigated. Two procedures were used to analyse fresh smooth dogfish (Mustelus canis) eye lenses that were incubated for up to 22 hr in vitro, with elasmobranch Ringer's medium, and with or without exposure to a near-UV lamp (emission principally at 365 nm; irradiance of 2.5 mW cm-2). These were observed histologically using phalloidin-rhodamine specific staining and by transmission electron microscopy. In addition, solutions of purified polymerized rabbit muscle actin were exposed to the same UV conditions and depolymerization was assayed by ultracentrifugation and high-pressure liquid chromatography. While the two actins studied do differ very slightly in some amino acid sequences, they would react physically nearly identically. The results showed that dogfish lenses developed superficial opacities due to near-UV exposure. Whole mounts of lens epithelium exhibited breakdown of actin filaments in the basal region of the cells within 18 hr of UV exposure. TEM confirmed the breakdown of actin filaments due to UV exposure. SDS-PAGE and immunoblotting positively identified actin in these cells. Direct exposure of purified polymerized muscle actin in polymerizing buffer led to an increase in actin monomer of approximately 25% in the UV-exposed solutions within 3-18 hr, whether assayed by ultracentrifugation or HPLC. The above indicates that elasmobranch lens epithelial cells contain UV-labile actin filaments, and that near-UV radiation, as is present in the sunlit environment, can break down the actin structure in these cells. Furthermore, breakdown of purified polymerized muscle actin does occur due to near-UV light exposure.(ABSTRACT TRUNCATED AT 250 WORDS)

  6. Comparative statistical analysis of carcinogenic and non-carcinogenic effects of uranium in groundwater samples from different regions of Punjab, India.

    Science.gov (United States)

    Saini, Komal; Singh, Parminder; Bajwa, Bikramjit Singh

    2016-12-01

    LED flourimeter has been used for microanalysis of uranium concentration in groundwater samples collected from six districts of South West (SW), West (W) and North East (NE) Punjab, India. Average value of uranium content in water samples of SW Punjab is observed to be higher than WHO, USEPA recommended safe limit of 30µgl -1 as well as AERB proposed limit of 60µgl -1 . Whereas, for W and NE region of Punjab, average level of uranium concentration was within AERB recommended limit of 60µgl -1 . Average value observed in SW Punjab is around 3-4 times the value observed in W Punjab, whereas its value is more than 17 times the average value observed in NE region of Punjab. Statistical analysis of carcinogenic as well as non carcinogenic risks due to uranium have been evaluated for each studied district. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

    International Nuclear Information System (INIS)

    Perrone, Carmen E.; Duan, Jian Dong; Jeffrey, Alan M.; Williams, Gary M.; Ahr, Hans-Juergen; Schmidt, Ulrich; Enzmann, Harald H.

    2004-01-01

    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 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 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.)

  8. Proposed changes in the classification of carcinogenic chemicals in the work area.

    Science.gov (United States)

    Neumann, H G; Thielmann, H W; Filser, J G; Gelbke, H P; Greim, H; Kappus, H; Norpoth, K H; Reuter, U; Vamvakas, S; Wardenbach, P; Wichmann, H E

    1997-12-01

    Carcinogenic chemicals in the work area are currently classified into three categories in Section III of the German List of MAK and BAT Values. This classification is based on qualitative criteria and reflects essentially the weight of evidence available for judging the carcinogenic potential of the chemicals. It is proposed that these Categories--IIIA1, IIIA2, and IIIB--be retained as Categories 1, 2, and 3, to conform with EU regulations. On the basis of our advancing knowledge of reaction mechanisms and the potency of carcinogens, it is now proposed that these three categories be supplemented with two additional categories. The essential feature of substances classified in the new categories is that exposure to these chemicals does not convey a significant risk of cancer to man, provided that an appropriate exposure limit (MAK value) is observed. It is proposed that chemicals known to act typically by nongenotoxic mechanisms and for which information is available that allows evaluation of the effects of low-dose exposures be classified in Category 4. Genotoxic chemicals for which low carcinogenic potency can be expected on the basis of dose-response relationships and toxicokinetics and for which risk at low doses can be assessed will be classified in Category 5. The basis for a better differentiation of carcinogens is discussed, the new categories are defined, and possible criteria for classification are described. Examples for Category 4 (1,4-dioxane) and Category 5 (styrene) are presented. The proposed changes in classifying carcinogenic chemicals in the work area are presented for further discussion.

  9. Morpho-chemical characterization and surface properties of carcinogenic zeolite fibers

    International Nuclear Information System (INIS)

    Mattioli, Michele; Giordani, Matteo; Dogan, Meral; Cangiotti, Michela; Avella, Giuseppe; Giorgi, Rodorico; Dogan, A. Umran; Ottaviani, Maria Francesca

    2016-01-01

    Highlights: • Differently carcinogenic zeolite fibers were investigated combining physico-chemical methods. • For the first time, zeolite fibers were studied by means of the EPR technique using different spin probes. • The structural properties and the adsorption capability are function of different types and distributions of adsorption sites. • The interacting ability of erionite is higher than that of other fibrous zeolites. • The surface interacting properties may be related with the carcinogenicity of the zeolite fibers. - Abstract: Erionite belonging to the zeolite family is a human health-hazard, since it was demonstrated to be carcinogenic. Conversely, offretite family zeolites were suspected carcinogenic. Mineralogical, morphological, chemical, and surface characterizations were performed on two erionites (GF1, MD8) and one offretite (BV12) fibrous samples and, for comparison, one scolecite (SC1) sample. The specific surface area analysis indicated a larger availability of surface sites for the adsorption onto GF1, while SC1 shows the lowest one and the presence of large pores in the poorly fibrous zeolite aggregates. Selected spin probes revealed a high adsorption capacity of GF1 compared to the other zeolites, but the polar/charged interacting sites were well distributed, intercalated by less polar sites (Si–O–Si). MD8 surface is less homogeneous and the polar/charged sites are more interacting and closer to each other compared to GF1. The interacting ability of BV12 surface is much lower than that found for GF1 and MD8 and the probes are trapped in small pores into the fibrous aggregates. In comparison with the other zeolites, the non-carcinogenic SC1 shows a poor interacting ability and a lower surface polarity. These results helped to clarify the chemical properties and the surface interacting ability of these zeolite fibers which may be related to their carcinogenicity.

  10. 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.)

  11. Diurnal changes in epidermal UV transmittance of plants in naturally high UV environments.

    Science.gov (United States)

    Barnes, Paul W; Flint, Stephan D; Slusser, James R; Gao, Wei; Ryel, Ronald J

    2008-06-01

    Studies were conducted on three herbaceous plant species growing in naturally high solar UV environments in the subalpine of Mauna Kea, Hawaii, USA, to determine if diurnal changes in epidermal UV transmittance (T(UV)) occur in these species, and to test whether manipulation of the solar radiation regime could alter these diurnal patterns. Additional field studies were conducted at Logan, Utah, USA, to determine if solar UV was causing diurnal T(UV) changes and to evaluate the relationship between diurnal changes in T(UV) and UV-absorbing pigments. Under clear skies, T(UV), as measured with a UV-A-pulse amplitude modulation fluorometer for leaves of Verbascum thapsus and Oenothera stricta growing in native soils and Vicia faba growing in pots, was highest at predawn and sunset and lowest at midday. These patterns in T(UV) closely tracked diurnal changes in solar radiation and were the result of correlated changes in fluorescence induced by UV-A and blue radiation but not photochemical efficiency (F(v)/F(m)) or initial fluorescence yield (F(o)). The magnitude of the midday reduction in T(UV) was greater for young leaves than for older leaves of Verbascum. Imposition of artificial shade eliminated the diurnal changes in T(UV) in Verbascum, but reduction in solar UV had no effect on diurnal T(UV) changes in Vicia. In Vicia, the diurnal changes in T(UV) occurred without detectable changes in the concentration of whole-leaf UV-absorbing compounds. Results suggest that plants actively control diurnal changes in UV shielding, and these changes occur in response to signals other than solar UV; however, the underlying mechanisms responsible for rapid changes in T(UV) remain unclear.

  12. A thermal after-effect of UV irradiation of muscle glycogen phosphorylase b.

    Directory of Open Access Journals (Sweden)

    Valeriya V Mikhaylova

    Full Text Available Different test systems are used to characterize the anti-aggregation efficiency of molecular chaperone proteins and of low-molecular-weight chemical chaperones. Test systems based on aggregation of UV-irradiated protein are of special interest because they allow studying the protective action of different agents at physiological temperatures. The kinetics of UV-irradiated glycogen phosphorylase b (UV-Phb from rabbit skeletal muscle was studied at 37°C using dynamic light scattering in a wide range of protein concentrations. It has been shown that the order of aggregation with respect to the protein is equal to unity. A conclusion has been made that the rate-limiting stage of the overall process of aggregation is heat-induced structural reorganization of a UV-Phb molecule, which contains concealed damage.

  13. Role of ultraviolet (UV) disinfection in infection control and environmental cleaning.

    Science.gov (United States)

    Qureshi, Zubair; Yassin, Mohamed H

    2013-06-01

    Ultraviolet (UV) radiation is capable of disinfecting surfaces, water and air. The UV technology was used for many years. However, safer and more effective delivery systems of UV radiation, make it a very useful option for disinfection. Effective disinfection of environmental surfaces is a key step in the prevention of spread of infectious agents. The traditional manual cleaning is essential in assuring adequate elimination of contamination. However, terminal cleaning is frequently suboptimal or unpredictable in many circumstances. UV-C radiation is an adjunctive disinfectant new technology that could kill a wide array of microorganisms including both vegetative and spore forming pathogens. The technology is getting more affordable and has produced consistent reproducible significant reduction of bacterial contamination.

  14. Literature review of levels and determinants of exposure to potential carcinogens and other agents in the road construction industry.

    Science.gov (United States)

    Burstyn, I; Kromhout, H; Boffetta, P

    2000-01-01

    Workers in the road construction industry include asphalt plant, ground construction, and road paving workers. These individuals can be exposed to a wide range of potentially hazardous substances. A summary of levels of exposure to different substances measured during road construction is presented. In modern road paving, workers typically are exposed to 0.1 to 2 mg/m3 of bitumen fume, which includes 10 to 200 ng/m3 of benzo(a)pyrene. Sampling strategies and analytical methods employed in each reviewed survey are described briefly. The published reports provide some insight into the identity of factors that influence exposure to bitumen among road construction workers: type of work performed, meteorological conditions, temperature of paved asphalt. However, there is a lack of (a) comprehensive and well-designed studies that evaluate determinants of exposure to bitumen in road construction, and (b) standard methods for bitumen sampling and analysis. Information on determinants of other exposures in road construction is either absent or limited. It is concluded that data available through published reports have limited value in assessing historical exposure levels in the road construction industry.

  15. 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.

  16. Participation of IPEN in the international program of information about occupational exposure to carcinogen risks

    International Nuclear Information System (INIS)

    Osores, Jose; Gonzales, Susana

    2014-01-01

    During 2014, the Peruvian Nuclear Energy Institute participated in the mapping of risks to carcinogens due to occupational exposure for our country through CAREX program because all radioactive substances are considered by the International Agency for Research Cancer as type 1 carcinogens (high risk) and the presence of these substances in the work environment are unknown to professionals from other institutions. This occasion allowed the incorporation of Natural Occurring Radioactive Materials (NORM) as indicators in all work activities that were not considered by the Energy and Mining Sector. (authors).

  17. Prediction of Chemical Carcinogenicity in Rodents from in vitro Genetic Toxicity Assays

    Science.gov (United States)

    Tennant, Raymond W.; Margolin, Barry H.; Shelby, Michael D.; Zeiger, Errol; Haseman, Joseph K.; Spalding, Judson; Caspary, William; Resnick, Michael; Stasiewicz, Stanley; Anderson, Beth; Minor, Robert

    1987-05-01

    Four widely used in vitro assays for genetic toxicity were evaluated for their ability to predict the carcinogenicity of selected chemicals in rodents. These assays were mutagenesis in Salmonella and mouse lymphoma cells and chromosome aberrations and sister chromatid exchanges in Chinese hamster ovary cells. Seventy-three chemicals recently tested in 2-year carcinogenicity studies conducted by the National Cancer Institute and the National Toxicology Program were used in this evaluation. Test results from the four in vitro assays did not show significant differences in individual concordance with the rodent carcinogenicity results; the concordance of each assay was approximately 60 percent. Within the limits of this study there was no evidence of complementarity among the four assays, and no battery of tests constructed from these assays improved substantially on the overall performance of the Salmonella assay. The in vitro assays which represented a range of three cell types and four end points did show substantial agreement among themselves, indicating that chemicals positive in one in vitro assay tended to be positive in the other in vitro assays. To help put this project into its proper context, we emphasize certain features of the study: 1) Standard protocols were used to mimic the major use of STTs worldwide--screening for mutagens and carcinogens; no attempt was made to optimize protocols for specific chemicals. 2) The 73 NTP chemicals and their 60% incidence of carcinogenicity are probably not representative of the universe of chemicals but rather reflect the recent chemical selection process for the NTP carcinogenicity assay. 3) The small, diverse group of chemicals precludes a meaningful evaluation of the predictive utility of chemical structure information. 4) The NTP is currently testing these same 73 chemicals in two in vivo STTs for chromosomal effects. 5) Complete data for an additional group of 30 to 40 NTP chemicals will be gathered on

  18. Enhancement of SV40 transformation by treatment of C3H2K cells with uv light and caffeine. I. Combined effect of uv light and caffeine

    International Nuclear Information System (INIS)

    Ide, T.; Anzai, K.; Andoh, T.

    1975-01-01

    Treatment of cultured mouse cells, C3H2K, with uv light and/or caffeine enhanced the frequency of SV40-induced transformation. This enhancement depends upon the doses of uv and caffeine and the mode of combination of these agents. Irradiation of cells with increasing doses of uv just before infection resulted in approximately 2-fold enhancement of the transformation frequency up to a dose of 90 ergs/mm 2 and 3.3-fold at 150 ergs/mm 2 . Addition of 1 mM caffeine to the medium for 4 days subsequent to infection brought about a 2-fold enhancement. When cells were irradiated and treated with 1 mM caffeine, the enhancement was approximately 4-fold up to a uv dose of 90 ergs/mm 2 and 5.9-fold at 150 ergs/mm 2 . When 0.1 to 4 mM caffeine was added for 4 days postinfection, the absolute number of transformations increased, and an enhancement ratio of 1.3 to 6.8 resulted. After the addition of the same increasing doses of caffeine to uv-irradiated cells (75 ergs/mm 2 ), the enhancement of transformation frequency was even higher ranging 2.0 to 13.3. The transformation frequencies thus obtained by the double treatment were always higher than those predicted if uv and caffeine acted additively. The transformation frequency was little affected by the addition of dibutyrylcyclic AMP and theophylline

  19. Microbial UV fluence-response assessment using a novel UV-LED collimated beam system.

    Science.gov (United States)

    Bowker, Colleen; Sain, Amanda; Shatalov, Max; Ducoste, Joel

    2011-02-01

    A research study has been performed to determine the ultraviolet (UV) fluence-response of several target non-pathogenic microorganisms to UV light emitting diodes (UV-LEDs) by performing collimated beam tests. UV-LEDs do not contain toxic mercury, offer design flexibility due to their small size, and have a longer operational life than mercury lamps. Comsol Multiphysics was utilized to create an optimal UV-LED collimated beam design based on number and spacing of UV-LEDs and distance of the sample from the light source while minimizing the overall cost. The optimized UV-LED collimated beam apparatus and a low-pressure mercury lamp collimated beam apparatus were used to determine the UV fluence-response of three surrogate microorganisms (Escherichia coli, MS-2, T7) to 255 nm UV-LEDs, 275 nm UV-LEDs, and 254 nm low-pressure mercury lamps. Irradiation by low-pressure mercury lamps produced greater E. coli and MS-2 inactivation than 255 nm and 275 nm UV-LEDs and similar T7 inactivation to irradiation by 275 nm UV-LEDs. The 275 nm UV-LEDs produced more efficient T7 and E. coli inactivation than 255 nm UV-LEDs while both 255 nm and 275 nm UV-LEDs produced comparable microbial inactivation for MS-2. Differences may have been caused by a departure from the time-dose reciprocity law due to microbial repair mechanisms. Copyright © 2010 Elsevier Ltd. All rights reserved.

  20. Synthesis and SAR studies of very potent imidazopyridine antiprotozoal agents.

    Science.gov (United States)

    Biftu, Tesfaye; Feng, Dennis; Fisher, Michael; Liang, Gui-Bai; Qian, Xiaoxia; Scribner, Andrew; Dennis, Richard; Lee, Shuliang; Liberator, Paul A; Brown, Chris; Gurnett, Anne; Leavitt, Penny S; Thompson, Donald; Mathew, John; Misura, Andrew; Samaras, Samantha; Tamas, Tamas; Sina, Joseph F; McNulty, Kathleen A; McKnight, Crystal G; Schmatz, Dennis M; Wyvratt, Matthew

    2006-05-01

    Compounds 10a (IC50 110 pM) and 21 (IC50 40 pM) are the most potent inhibitors of Eimeria tenella cGMP-dependent protein kinase activity reported to date and are efficacious in the in vivo antiparasitic assay when administered to chickens at 12.5 and 6.25 ppm levels in the feed. However, both compounds are positive in the Ames microbial mutagenesis assay which precludes them from further development as antiprotozoal agents in the absence of negative lifetime rodent carcinogenicity studies.

  1. 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

  2. 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.

  3. A CCD-based system for the detection of DNA in electrophoresis gels by UV absorption

    International Nuclear Information System (INIS)

    Mahon, A.R.; MacDonald, J.H.; Mainwood, A.; Ott, R.J.

    1999-01-01

    A method and apparatus for the detection and quantification of large fragments of unlabelled nucleic acids in agarose gels is presented. The technique is based on ultraviolet (UV) absorption by nucleotides. A deuterium source illuminates individual sample lanes of an electrophoresis gel via an array of optical fibres. As DNA bands pass through the illuminated region of the gel the amount of UV light transmitted is reduced because of absorption by the DNA. During electrophoresis the regions of DNA are detected on-line using a UV-sensitive charge coupled device (CCD). As the absorption coefficient is proportional to the mass of DNA the technique is inherently quantitative. The mass of DNA in a region of the gel is approximately proportional to the integrated signal in the corresponding section of the CCD image. This system currently has a detection limit of less than 1.25 ng compared with 2-10 ng for the most popular conventional technique, ethidium bromide (EtBr) staining. In addition the DNA sample remains in its native state. The removal of the carcinogenic dye from the detection procedure greatly reduces associated biological hazards. (author)

  4. 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.

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

    International Nuclear Information System (INIS)

    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)

  6. Reasoning about emotional agents

    OpenAIRE

    Meyer, J.-J.

    2004-01-01

    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 framework how emotions are related to the action monitoring capabilities of an agent.

  7. COMPARATIVE ANALYSIS OF UV-C AND UV-B RADIATION INFLUENCE ON PLANT OBJECTS

    Directory of Open Access Journals (Sweden)

    О. Міхєєв

    2011-04-01

    Full Text Available General aim of work – comparative research of temporal regularities of growth processes of pea,that was grown under normal conditions and with application of UV-C and UV-B irradiation ofstem part, and also detection of irradiation dose relations to parameter of root and stem part sproutsgrowth rate of Aronis pea. Research subject of UV-C and UV-B irradiation influence on dynamicsof plant growth parameters in each set of experiments was alteration of growth rate, pecularities ofgrowth dynamics in different conditions of experiment, detection of UV-C and UV-B irradiationdoses range, that stimulate or inhibit growth parameters of pea sprouts. The investigation resulted indetermination 1,3 times higher efficiency of UV-V irradiation comparing to UV-B irradiation.Reaction of root didn’t depend on the type of UV-radiation

  8. Moving forward in carcinogenicity assessment : Report of an EURL ECVAM/ESTIV workshop

    NARCIS (Netherlands)

    Corvi, Raffaella; Madia, Federica; Guyton, Kathryn Z; Kasper, Peter; Rudel, Ruthann; Colacci, Annamaria; Kleinjans, Jos; Jennings, Paul

    2017-01-01

    There is an increased need to develop novel alternative approaches to the two-year rodent bioassay for the carcinogenicity assessment of substances where the rodent bioassay is still a basic requirement, as well as for those substances where animal use is banned or limited or where information gaps

  9. Search for Internal Cancers in Mice Tattooed with Inks of High Contents of Potential Carcinogens

    DEFF Research Database (Denmark)

    Sepehri, Mitra; Lerche, Catharina M; Hutton Carlsen, Katrina

    2017-01-01

    on the Danish market due to the measured contents of potential carcinogens; benzo(a)pyrene and 2-anisidine, respectively. The mice were housed for 1 year after tattooing, and autopsy study on internal organs was performed. Tissue samples were systematically taken from major organs for screening of subclinical...

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

    International Nuclear Information System (INIS)

    Goldthwait, D.A.

    1985-01-01

    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

  11. Morpho-chemical characterization and surface properties of carcinogenic zeolite fibers.

    Science.gov (United States)

    Mattioli, Michele; Giordani, Matteo; Dogan, Meral; Cangiotti, Michela; Avella, Giuseppe; Giorgi, Rodorico; Dogan, A Umran; Ottaviani, Maria Francesca

    2016-04-05

    Erionite belonging to the zeolite family is a human health-hazard, since it was demonstrated to be carcinogenic. Conversely, offretite family zeolites were suspected carcinogenic. Mineralogical, morphological, chemical, and surface characterizations were performed on two erionites (GF1, MD8) and one offretite (BV12) fibrous samples and, for comparison, one scolecite (SC1) sample. The specific surface area analysis indicated a larger availability of surface sites for the adsorption onto GF1, while SC1 shows the lowest one and the presence of large pores in the poorly fibrous zeolite aggregates. Selected spin probes revealed a high adsorption capacity of GF1 compared to the other zeolites, but the polar/charged interacting sites were well distributed, intercalated by less polar sites (Si-O-Si). MD8 surface is less homogeneous and the polar/charged sites are more interacting and closer to each other compared to GF1. The interacting ability of BV12 surface is much lower than that found for GF1 and MD8 and the probes are trapped in small pores into the fibrous aggregates. In comparison with the other zeolites, the non-carcinogenic SC1 shows a poor interacting ability and a lower surface polarity. These results helped to clarify the chemical properties and the surface interacting ability of these zeolite fibers which may be related to their carcinogenicity. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Methodology in use for the assessment of carcinogenic risk. II. Radiation. Oncology overview

    International Nuclear Information System (INIS)

    1983-04-01

    Oncology Overviews are a service of the International Cancer Research Data Bank (ICRDB) Program of the National Cancer Institute, intended to facilitate and promote the exchange of information between cancer scientists by keeping them aware of literature related to their research being published by other laboratories throughout the world. Each Oncology Overview represents a survey of the literature associated with a selected area of cancer research. It contains abstracts of articles which have been selected and organized by researchers associated with the field. Contents: Assessment of carcinogenic risk from environmental and occupational exposures to ionizing radiation; Assessment of carcinogenic risk from exposure to ionizing radiation used for medical diagnosis or treatment; Assessment of carcinogenic risk from exposure to ionizing radiation following nuclear bomb explosions; Comparison of risk from radiation sources with risk from nonradiation sources; Experimental studies to assess risk of carcinogenesis following exposure to ionizing radiation; Theoretical aspects of dose-response relationships in the assessment of carcinogenic risk from exposure to ionizing radiation; Public policy and standards for acceptable risk from exposure to ionizing radiation; General reviews on the assessment of risk from exposure to ionizing radiation

  13. Asian Americans and disproportionate exposure to carcinogenic hazardous air pollutants: A national study.

    Science.gov (United States)

    Grineski, Sara E; Collins, Timothy W; Morales, Danielle X

    2017-07-01

    Studies have demonstrated disparate exposures to carcinogenic hazardous air pollutants (HAPs) in neighborhoods with high densities of Black and Hispanic residents in the US. Asians are the fastest growing racial/ethnic group in the US, yet they have been underemphasized in previous studies of environmental health and injustice. This cross-sectional study investigated possible disparities in residential exposure to carcinogenic HAPs among Asian Americans, including Asian American subgroups in the US (including all 50 states and the District of Columbia, n = 71,208 US census tracts) using National Air Toxics Assessment and US Census data. In an unadjusted analysis, Chinese and Korean Americans experience the highest mean cancer risks from HAPs, followed by Blacks. The aggregated Asian category ranks just below Blacks and above Hispanics, in terms of carcinogenic HAP risk. Multivariate models adjusting for socioeconomic status, population density, urban location, and geographic clustering show that an increase in proportion of Asian residents in census tracts is associated with significantly greater cancer risk from HAPs. Neighborhoods with higher proportions (as opposed to lower proportions) of Chinese, Korean, and South Asian residents have significantly greater cancer risk burdens relative to Whites. Tracts with higher concentrations of Asians speaking a non-English language and Asians that are US-born have significantly greater cancer risk burdens. Asian Americans experience substantial residential exposure to carcinogenic HAPs in US census tracts and in the US more generally. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    NARCIS (Netherlands)

    Schutte, M.E.; Sandt, J.J.M. van de; 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

  15. Approaches to the risk assessment of genotoxic carcinogens in food: a critical appraisal.

    NARCIS (Netherlands)

    O'Brien, J; Renwick, A G; Constable, A; Dybing, Erik; Müller, D J G; Schlatter, J; Slob, Wout; Tueting, W; Benthem, Jan van; Williams, G M; Wolfreys, A

    2006-01-01

    The present paper examines the particular difficulties presented by low levels of food-borne DNA-reactive genotoxic carcinogens, some of which may be difficult to eliminate completely from the diet, and proposes a structured approach for the evaluation of such compounds. While the ALARA approach is

  16. Mutagenicity of food-derived carcinogens and the effect of antioxidant vitamins.

    Science.gov (United States)

    Montgomery, Beverly A; Murphy, Jessica; Chen, James J; Desai, Varsha G; McGarrity, Lynda; Morris, Suzanne M; Casciano, Daniel A; Aidoo, Anane

    2002-01-01

    The food-derived heterocyclic amines (HCAs) 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) are mutagenic in the Ames test and produce tumors in laboratory animals, including monkeys. These HCAs have also been shown to induce gene mutations in vivo. To assess the antimutagenic effects of dietary antioxidant vitamins, beta-carotene, ascorbic acid (vitamin C), and alpha-tocopherol (vitamin E), on food-borne mutagenes/carcinogens, we evaluated the mutagenic activity of the compounds alone or combined with antioxidant vitamins. We utilized the rat lymphocyte mutation assay at the hypoxanthine guanine phosphoribosyl transferase (Hprt) locus. Female Fischer 344 rats treated with different doses (0, 2.5, 5.0, 25.0, and 50.0 mg/kg) of the carcinogens were sacrificed 5 wk after mutagen treatment. Although IQ and MeIQ slightly increased mutation frequency (MF) at some doses, a significant (P carcinogen metabolism would be affected by ingestion of vitamins. The activities of endogenous detoxification enzymes, glutathione S-transferase and glutathione peroxidase (GPx), were thus examined. Intake of beta-carotene and vitamin C without the carcinogen resulted in an increase (P food or taken as supplements could, in part, counteract such mutagenic activities.

  17. Biomarkers of exposure to carcinogenic PAHs and their relationship with environmental factors

    Czech Academy of Sciences Publication Activity Database

    Taioli, E.; Šrám, Radim; Binková, Blanka; Kalina, I.; Popov, T. A.; Garte, S.; Farmer, P. B.

    2007-01-01

    Roč. 620, - (2007), s. 16-21 ISSN 0027-5107 Grant - others:EU(GB) 2000-00091 Institutional research plan: CEZ:AV0Z50390512 Source of funding: R - rámcový projekt EK Keywords : DNA adducts * air pollution * carcinogenic PAHs Subject RIV: DN - Health Impact of the Environment Quality Impact factor: 4.159, year: 2007

  18. An evaluation of the mode of action framework for mutagenic carcinogens: Chromium (VI): SOT.

    Science.gov (United States)

    In response to the 2005 revised U.S Environmental Protection Agency’s (EPA) Cancer Guidelines, a strategy is being developed to determine whether a carcinogen operates through a mutagenic mode of action (MOA). This information is necessary for EPA to decide whether age-dependent ...

  19. An evaluation of the mode of action framework for mutagenic carcinogens: chromium (VI)

    Science.gov (United States)

    In response to the 2005 revised U.S Environmental Protection Agency’s (EPA) Cancer Guidelines, a strategy is being developed to determine whether a carcinogen operates through a mutagenic mode of action (MOA). This information is necessary for EPA to decide whether age-dependent ...

  20. 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)

  1. TLR2 Controls Intestinal Carcinogen Detoxication by CYP1A1

    DEFF Research Database (Denmark)

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

    2012-01-01

    of ligands for TLR2 of bacterial origin seems to be crucial for detoxication of luminal carcinogens by CYP1A1 in the intestine. This unprecedented finding indicates a complex interplay between the immune system of the host and intestinal bacteria with detoxication mechanisms. This highlights the relevance...

  2. Production of carcinogenic acetaldehyde by Candida albicans from patients with potentially malignant oral mucosal disorders.

    Science.gov (United States)

    Gainza-Cirauqui, M L; Nieminen, M T; Novak Frazer, L; Aguirre-Urizar, J M; Moragues, M D; Rautemaa, R

    2013-03-01

    Production of carcinogenic acetaldehyde by Candida has been suggested to contribute to epithelial dysplasia and oral carcinogenesis. Oral lichen planus (OLP), oral lichenoid lesion (OLL) and oral leukoplakia (OL) are potentially carcinogenic oral diseases where colonisation by Candida is common, but acetaldehyde production by Candida has not been studied. Acetaldehyde production in ethanol (11 mM), glucose (100 mM), ethanol-glucose (11 mM and 100 mM) or red wine (1200 mM ethanol) incubation by Candida albicans from patients with OLL (n = 6), OLP (n = 16), OL (n = 6) and controls (n = 6) was measured by gas chromatography. Participants completed a questionnaire regarding their smoking habits and alcohol consumption. All Candida albicans isolates produced potentially carcinogenic levels of acetaldehyde (>100 μM) in all incubations containing ethanol. The control group isolates produced the highest acetaldehyde levels. Isolates from smokers produced more acetaldehyde in all incubations than those from non-smokers. The difference was significant in ethanol-glucose incubation. Isolates from patients who were both smokers and drinkers produced the highest amounts when incubated in ethanol, ethanol-glucose and wine. Candida albicans isolated from potentially carcinogenic oral diseases can produce mutagenic amounts of acetaldehyde. Cigarette smoking and alcohol consumption may favour adaptational changes resulting in the upregulation of candidal acetaldehyde metabolism. © 2012 John Wiley & Sons A/S. All rights reserved.

  3. 78 FR 4419 - Draft Report on Carcinogens Monographs for 1-Bromopropane and Cumene; Availability of Documents...

    Science.gov (United States)

    2013-01-22

    ... Monographs for 1-Bromopropane and Cumene; Availability of Documents; Request for Comments; Notice of Meeting SUMMARY: Peer review meeting of the Draft Report on Carcinogens (RoC) Monographs for 1-Bromopropane and... monographs will be available by January [[Page 4420

  4. SYN-JEM : A Quantitative Job-Exposure Matrix for Five Lung Carcinogens

    NARCIS (Netherlands)

    Peters, Susan; Vermeulen, Roel; Portengen, L??tzen; Olsson, Ann; Kendzia, Benjamin; Vincent, Raymond; Savary, Barbara; LavouCrossed Sign, Jcrossed D Signr??me; Cavallo, Domenico; Cattaneo, Andrea; Mirabelli, Dario; Plato, Nils; Fevotte, Joelle; Pesch, Beate; Br??ning, Thomas; Straif, Kurt; Kromhout, Hans

    2016-01-01

    OBJECTIVE The use of measurement data in occupational exposure assessment allows more quantitative analyses of possible exposure-response relations. We describe a quantitative exposure assessment approach for five lung carcinogens (i.e. asbestos, chromium-VI, nickel, polycyclic aromatic hydrocarbons

  5. 78 FR 57868 - Nominations to the Report on Carcinogens; Request for Information

    Science.gov (United States)

    2013-09-20

    ... Carcinogens (ORoC) requests information on 20 substances, mixtures, and exposure circumstances (collectively... for the following topics: (1) data on current production, use patterns, and human exposure; (2... (CAS No. 108-10-1) Nickel nanoparticles Nitro polycyclic aromatic hydrocarbons (PAH) as a class...

  6. SYN-JEM : A Quantitative Job-Exposure Matrix for Five Lung Carcinogens

    NARCIS (Netherlands)

    Peters, Susan; Vermeulen, Roel; Portengen, Lützen; Olsson, Ann C.; Kendzia, Benjamin; Vincent, Raymond; Savary, Barbara; LavouCrossed Sign, Jcrossed D.Signrôme; Cavallo, Domenico; Cattaneo, Andrea; Mirabelli, Dario; Plato, Nils; Fevotte, Joelle; Pesch, Beate; Brüning, Thomas; Straif, Kurt; Kromhout, Hans

    2016-01-01

    Objective: The use of measurement data in occupational exposure assessment allows more quantitative analyses of possible exposure-response relations. We describe a quantitative exposure assessment approach for five lung carcinogens (i.e. asbestos, chromium-VI, nickel, polycyclic aromatic

  7. 78 FR 67372 - Evaluation of Trichloroethylene for the Report on Carcinogens; Request for Nominations of...

    Science.gov (United States)

    2013-11-12

    ... Trichloroethylene for the Report on Carcinogens; Request for Nominations of Scientific Experts for Proposed Webinar... association of exposure to trichloroethylene (TCE) and cancer. DATES: The deadline for receipt of nominations.../Trichloroethylene.pdf ). The NTP selected TCE for evaluation to determine whether a change in its listing status in...

  8. Environmental Carcinogen Releases and Lung Cancer Mortality in Rural-Urban Areas of the United States

    Science.gov (United States)

    Luo, Juhua; Hendryx, Michael

    2011-01-01

    Purpose: Environmental hazards are unevenly distributed across communities and populations; however, little is known about the distribution of environmental carcinogenic pollutants and lung cancer risk across populations defined by race, sex, and rural-urban setting. Methods: We used the Toxics Release Inventory (TRI) database to conduct an…

  9. On the carcinogenic polycyclic aromatic hydrocarbon benzo(a)pyrene in volcano exhausts.

    Science.gov (United States)

    Ilnitsky, A P; Belitsky, G A; Shabad, L M

    1976-05-01

    The content of benzo(a)pyrene in the juvenile ashes of the volcano Tyatya (Kunashir Island, Kuriles) and in the soil, vegetation and volcanic mud collected near volcanos in Kamchatka was studied. It was concluded that volcanic activity does not play a large role in forming the background level of this carcinogen in the human environment.

  10. Mode of carcinogenic action of pesticides inducing thyroid follicular cell tumors in rodents.

    Science.gov (United States)

    Hurley, P M

    1998-08-01

    Of 240 pesticides screened for carcinogenicity by the U.S. Environmental Protection Agency Office of Pesticide Programs, at least 24 (10%) produce thyroid follicular cell tumors in rodents. Thirteen of the thyroid carcinogens also induce liver tumors, mainly in mice, and 9 chemicals produce tumors at other sites. Some mutagenic data are available on all 24 pesticides producing thyroid tumors. Mutagenicity does not seem to be a major determinant in thyroid carcinogenicity, except for possibly acetochlor; evidence is less convincing for ethylene thiourea and etridiazole. Studies on thyroid-pituitary functioning, including indications of thyroid cell growth and/or changes in thyroxine, triiodothyronine, or thyroid-stimulating hormone levels, are available on 19 pesticides. No such antithyroid information is available for etridiazole, N-octyl bicycloheptene dicarboximide, terbutryn, triadimefon, and trifluralin. Of the studied chemicals, only bromacil lacks antithyroid activity under study conditions. Intrathyroidal and extrathyroidal sites of action are found: amitrole, ethylene thiourea, and mancozeb are thyroid peroxidase inhibitors; and acetochlor, clofentezine, fenbuconazole, fipronil, pendimethalin, pentachloronitrobenzene, prodiamine, pyrimethanil, and thiazopyr seem to enhance the hepatic metabolism and excretion of thyroid hormone. Thus, with 12 pesticides that mode of action judgments can be made, 11 disrupt thyroid-pituitary homeostasis only; no chemical is mutagenic only; and acetochlor may have both antithyroid and some mutagenic activity. More information is needed to identify other potential antithyroid modes of thyroid carcinogenic action.

  11. To the application of the emission Mössbauer and positron annihilation spectroscopies for detection of carcinogens

    Science.gov (United States)

    Bokov, A. V.; Byakov, V. M.; Kulikov, L. A.; Perfiliev, Yu. D.; Stepanov, S. V.

    2017-11-01

    Being the main cause of cancer, almost all chemical carcinogens are strong electrophiles, that is, they have a high affinity for the electron. We have shown that positron annihilation lifetime spectroscopy (PALS) is able to detect chemical carcinogens by their inhibition of positronium (Ps) formation in liquid media. Electrophilic carcinogens intercept thermalized track electrons, which are precursors of Ps, and as a result, when they are present Ps atom does not practically form. Available biophysical data seemingly indicate that frozen solutions model better an intracellular medium than the liquid ones. So it is reasonable to use emission Mössbauer spectroscopy (EMS) to detect chemical carcinogens, measuring the yield of 57Fe2+ions formed in reactions of Auger electrons and other secondary electrons they produced with 57Fe3+. These reactions are similar to the Ps formation process in the terminal part the positron track: e++ e- =>Ps. So EMS and PALS are complementary methods for detection of carcinogenic compounds.

  12. UV lamp for photoelectron spectroscopy

    International Nuclear Information System (INIS)

    Cardoso, M.J.B.; Landers, R.; Sundaram, V.S.

    1983-01-01

    An UV lamp and a differential pumping system which enables to couple the lamp to an ultra-high vacuum chamber (10 -9 torr) without using windows, are described. The differential between the pressure inside the discharge chamber and the one in de UHV region, which is of 10 8 -10 9 , is achieved with two pumping states separated by pyrex capillaries having an internal diameter of 0.6 mm. In the first stage, a mechanical pump (10 -3 torr) is used; in the second stage, a diffusor pump with a cryogenic trap (N 2 liq - 10 -7 torr) is employed. The lamp produces, when used with high purity He, narrow lines almost clear at 21.2 eV and 40.8 eV, depending on the discharge chamber pressure, thus eliminating the need of a monochromator. As a high voltage source (3 KV), a commercial unit with a good current control was used, ensuring UV beam stability - an essential characteristic for this lamp if it is employed for photoelectron excitation of crystalline samples. (C.L.B.) [pt

  13. Blocking by the carcinogen, L-ethionine, of SOS functions in a tif-1 mutant of Escherichia coli B/r

    International Nuclear Information System (INIS)

    Wiesner, R.; Troll, W.

    1981-01-01

    In Escherichia coli, DNA damage by carcinogenic agents results in the coordinate expression of a diversity of functions (SOS functions), many of which are thermally inducible without any damage to DNA in a tif-1 mutant. These include prophage induction, filamentous growth, and an error-prone DNA repair activity, which is responsible for ultraviolet-induced mutagenesis. Ethionine causes hepatic carcinoma in rats after prolonged feeding but is not a mutagen in the Ames test. The present study shows that 10 mM ethionine prevents the thermal induction of lambda-prophage in a tif-1 derivative of E. coli. The enhancement of mutation, which normally occurs at high temperature after a low dose of ultraviolet light, is also blocked by ethionine. Ethionine does not block, to any appreciable extent, the incorporation of radioactive precursors into RNA, DNA, or protein

  14. The comparative estimation of the radiation and chemical carcinogenic risk induced by the atmosphere contamination due to releases from coal-fired power plants

    International Nuclear Information System (INIS)

    Knizhnikov, V.A.; Komleva, V.A.; Shandala, N.K.

    1992-01-01

    In experiments with 1000 white mongrel mice which inhaled benzo (a) pyrene (BP) and fly coal ash for a long time, these agents increased significantly lung tumour incidence, with the latent period shortened. BP is found to be 10-1000 fold more carcinogenic then fly coal ash. The BP inhalation at a sanitary standard level (0.1 μg/100m 3 ) appeared to be equivalent, in murine risk, to the whole-body exposure to a total gamma dose of about 2 Sv. The coal ash inhalation in a concentration of 0.05 mg/m 3 caused the same risk as a dose of 0.05 Sv. (author)

  15. A novel research model for evaluating sunscreen protection in the UV-A1.

    Science.gov (United States)

    Figueiredo, Sônia Aparecida; de Moraes, Dayane Cristina; Vilela, Fernanda Maria Pinto; de Faria, Amanda Natalina; Dos Santos, Marcelo Henrique; Fonseca, Maria José Vieira

    2018-01-01

    The use of a broad spectrum sunscreen is considered one of the main and most popular measures for preventing the damaging effects of ultraviolet radiation (UVR) on the skin. In this study we have developed a novel in vitro method to assess sunscreens efficacy to protect calcineurin enzyme activity, a skin cell marker. The photoprotective efficacy of sunscreen products was assessed by measuring the UV-A1 radiation-induced depletion of calcineurin (Cn) enzyme activity in primary neonatal human dermal fibroblast (HDFn) cell lysates. After exposure to 24J/cm 2 UV-A1 radiation, the sunscreens containing larger amounts of UV-A1 filters (brand B), the astaxanthin (UV-A1 absorber) and the Tinosorb® M (UV-A1 absorber) were capable of preventing loss of Cn activity when compared to the sunscreens formulations of brand A (low concentration of UV-A1 filters), with the Garcinia brasiliensis extract (UV-B absorber) and with the unprotected cell lysate and exposed to irradiation (Irradiated Control - IC). The Cn activity assay is a reproducible, accurate and selective technique for evaluating the effectiveness of sunscreens against the effects of UV-A1 radiation. The developed method showed that calcineurin activity have the potential to act as a biological indicator of UV-A1 radiation-induced damages in skin and the assay might be used to assess the efficacy of sunscreens agents and plant extracts prior to in vivo tests. Copyright © 2017 Elsevier B.V. All rights reserved.

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

    International Nuclear Information System (INIS)

    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

  17. 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.

  18. Efficiency of ocular UV protection by clear lenses.

    Science.gov (United States)

    Rifai, Katharina; Hornauer, Matthias; Buechinger, Ramona; Schoen, Roland; Barraza-Bernal, Maria; Habtegiorgis, Selam; Glasenapp, Carsten; Wahl, Siegfried; Mappes, Timo

    2018-04-01

    Ocular UV doses accumulate all-day, not only during periods of direct sun exposure. The UV protection efficiency of three clear lenses was evaluated experimentally, validated by simulation, and compared to non-UV protection: a first spectacle lens with a tailored UV absorber, a second spectacle lens, minimizing UV back reflections, as well as a third spectacle lens, combining both. A tailored UV-absorber efficiently reduced overall UV irradiance to 7 %, whereas reduction of back-reflections still left UV irradiance at 42 %. Thus, clear lenses with a tailored UV absorber efficiently protect the eye from UV, supplementing sun glasses wear to an all-day protection scenario.

  19. Effects of UV radiation on freshwater metazooplankton

    International Nuclear Information System (INIS)

    Tartarotti, B.

    1999-06-01

    There is evidence that fluxes of solar ultraviolet-B radiation (UV-B, 290-320 nm) are increasing over wide parts of the earth's surface due to stratospheric ozone depletion. UV radiation (290-400 nm) can have damaging effects on biomolecules and cell components that are common to most living organisms. The aim of this thesis is to gain a more thorough understanding of the potential impacts of solar radiation on freshwater metazooplankton. To detect UV-vulnerability in zooplankton populations dominating the zooplankton community of two clear-water, high mountain lakes located one in the Austrian Alps and another in the Chilean Andes, the survival of two copepod species was studied. The organisms were exposed to a 10- to 100-fold increase in UV-B radiation compared to those levels found at their natural, maximum daytime distribution. Both species vertically migrate and are pigmented. UV-absorbing compounds with a maximum absorption at ∼334 nm were also detected. Cyclops abyssorum tatricus, a common cyclopoid copepod species of Alpine lakes, was highly resistant to UV-B radiation and no significant lethal effect was observed. The calanoid copepod Boeckella gracilipes, frequent in Andean lakes, had a mortality ∼5 times higher in the treatment receiving full sunlight than in the UV-B excluded treatment (3.2 %) only when exposed for 70 h. The resistance of B. gracilipes was higher than that reported in the literature for the same species suggesting the existence of intraspecific differences in UV sensitivity. Survival, fecundity and development of the zooplankton community of a clear-water, high elevation Andean lake (33 o S) were studied with mesocosms experiments after prolonged UV exposure (48 days). When exposed to full sunlight, the population of the cladoceran Chydorus sphaericus and the rotifer Lepadella ovalis were strongly inhibited by UV-B, whereas both species were resistant to UV-A radiation. Conversely, UV-B radiation had no effect on the survival of the

  20. [Light protection: principles of UV protection].

    Science.gov (United States)

    Stege, H; Mang, R

    2006-05-01

    UV radiation is responsible for the induction of epithelial and melanocytic skin cancer, photoaging, and photodermatoses. UV protection is necessary to prevent damage caused by non-physiologic exposure. UV protection includes not only reduction of sun exposure but also use of sun protective filters, UV protective clothes, DNA repair enzymes, and antioxidant supplementation. Consumers are uncertain about the possibilities and limitations of commercial sun protection measures. Dermatologists must explain protective measures to the general public which continues to believe that UV-tanned skin is healthy. The sunscreen market is a highly competitive but lucrative market. The range of products with different designations and promises makes difficult for both consumers and dermatologists to determine what is sensible UV protection.

  1. Developmental Transcriptomic Features of the Carcinogenic Liver Fluke, Clonorchis sinensis

    Science.gov (United States)

    Cho, Pyo Yun; Kim, Tae Im; Cho, Shin-Hyeong; Choi, Sang-Haeng; Park, Hong-Seog; Kim, Tong-Soo; Hong, Sung-Jong

    2011-01-01

    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, bile chemotaxis, and

  2. 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

  3. A study of tobacco carcinogenesis XLVIII. Carcinogenicity of N'-nitrosonornicotine in mink (Mustela vison).

    Science.gov (United States)

    Koppang, N; Rivenson, A; Reith, A; Dahle, H K; Evensen, O; Hoffmann, D

    1992-11-01

    During tobacco processing and smoking, nicotine and nornicotine give rise to N'-nitrosonornicotine (NNN), a highly abundant, strong carcinogen. NNN is known to exert carcinogenic activity in mice, rats and hamsters. Major target organs for NNN carcinogenicity in the rat are the esophagus and the nasal mucosa, and in the Syrian golden hamster trachea and nasal mucosa. In comparison with the rat, the mink (Mustela vison) has a markedly expanded nasal mucosa. Therefore, we explored in this study whether the mink could serve as a non-rodent model for nasal carcinogenesis using NNN as the carcinogen. Twenty random-bred mink, beginning at the age of 3 weeks, received twice weekly s.c. injections of NNN, a total dose of 11.9 mM per animal over a 38 week period. All of the 19 mink at risk developed malignant tumors of both the respiratory and the olfactory region of the nose within 3.5 years. In most animals the malignant tumors, primarily esthesioneuroepithelioma, invaded the brain. Remarkably, NNN induced no other tumors in the mink. None of the control animals developed nasal tumors nor tumors at other sites during the 3.5 years of the assay. The historical data from the farm did not reveal any spontaneous occurrence of nasal tumors in mink at any age. This study supports the concept that NNN is a proven carcinogen for multiple species of mammals and that the mink can serve as a non-rodent, non-inbred animal model for nasal carcinogenesis, especially since NNN induces only tumors in the nasal cavity in this species and not at other sites, as it does in mice, rats and hamsters.

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

    International Nuclear Information System (INIS)

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

    2014-01-01

    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

  5. Effect of chemical mutagens and carcinogens on gene expression profiles in human TK6 cells.

    Directory of Open Access Journals (Sweden)

    Lode Godderis

    Full Text Available Characterization of toxicogenomic signatures of carcinogen exposure holds significant promise for mechanistic and predictive toxicology. In vitro transcriptomic studies allow the comparison of the response to chemicals with diverse mode of actions under controlled experimental conditions. We conducted an in vitro study in TK6 cells to characterize gene expression signatures of exposure to 15 genotoxic carcinogens frequently used in European industries. We also examined the dose-responsive changes in gene expression, and perturbation of biochemical pathways in response to these carcinogens. TK6 cells were exposed at 3 dose levels for 24 h with and without S9 human metabolic mix. Since S9 had an impact on gene expression (885 genes, we analyzed the gene expression data from cells cultures incubated with S9 and without S9 independently. The ribosome pathway was affected by all chemical-dose combinations. However in general, no similar gene expression was observed among carcinogens. Further, pathways, i.e. cell cycle, DNA repair mechanisms, RNA degradation, that were common within sets of chemical-dose combination were suggested by clustergram. Linear trends in dose-response of gene expression were observed for Trichloroethylene, Benz[a]anthracene, Epichlorohydrin, Benzene, and Hydroquinone. The significantly altered genes were involved in the regulation of (anti- apoptosis, maintenance of cell survival, tumor necrosis factor-related pathways and immune response, in agreement with several other studies. Similarly in S9+ cultures, Benz[a]pyrene, Styrene and Trichloroethylene each modified over 1000 genes at high concentrations. Our findings expand our understanding of the transcriptomic response to genotoxic carcinogens, revealing the alteration of diverse sets of genes and pathways involved in cellular homeostasis and cell cycle control.

  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. Comparison of alkylating agent and radiation carcinogenesis: some aspects of the possible involvement of effects on DNA

    International Nuclear Information System (INIS)

    Lawley, P.D.

    1976-01-01

    A series of alkylating agents was classified in terms of increasing relative ability to react at O-atom sites in DNA, MMS 6 -alkylguanines are directly miscoding bases. This series of agents was also used in a study of comparative carcinogenicity with respect to induction of thymic lymphoma in mice, a system in which x-irradiation yields tumors. A positive correlation between ability of agents to alkylate O-6 of guanine in DNA of thymus and carcinogenic potency was found. Although MMS was not active in this system, it was noted that it can induce tumors in other systems. The relationship between repair of alkylation and radiation induced damage in DNA was briefly discussed. The methylating agents induce single-strand breaks in DNA, and the principal repair system appears to fall into the category of short repair as denoted by Regan and Setlow (1974). These single-strand breaks may result from spontaneous hydrolytic depurinations of 3- and 7-methylpurines, or from enzymatic depurinations, e.g., of 3-alkyladenine and O 6 -alkylguanine. Aralkylating agents, which are also carcinogens, can evoke an alternative repair response of the uvr type

  8. Chemical warfare agents.

    Science.gov (United States)

    Kuca, Kamil; Pohanka, Miroslav

    2010-01-01

    Chemical warfare agents are compounds of different chemical structures. Simple molecules such as chlorine as well as complex structures such as ricin belong to this group. Nerve agents, vesicants, incapacitating agents, blood agents, lung-damaging agents, riot-control agents and several toxins are among chemical warfare agents. Although the use of these compounds is strictly prohibited, the possible misuse by terrorist groups is a reality nowadays. Owing to this fact, knowledge of the basic properties of these substances is of a high importance. This chapter briefly introduces the separate groups of chemical warfare agents together with their members and the potential therapy that should be applied in case someone is intoxicated by these agents.

  9. UV-Induced Cell Death in Plants

    Science.gov (United States)

    Nawkar, Ganesh M.; Maibam, Punyakishore; Park, Jung Hoon; Sahi, Vaidurya Pratap; Lee, Sang Yeol; Kang, Chang Ho

    2013-01-01

    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). PMID:23344059

  10. UV disinfection in drinking water supplies.

    Science.gov (United States)

    Hoyer, O

    2000-01-01

    UV disinfection has become a practical and safely validatable disinfection procedure by specifying the requirements for testing and monitoring in DVGW standard W 294. A standardized biodosimetric testing procedure and monitoring with standardized UV sensors is introduced and successfully applied. On-line monitoring of irradiance can be counterchecked with handheld reference sensors and makes it possible that UV systems can be used for drinking water disinfection with the same level of confidence and safety as is conventional chemical disinfection.

  11. TRANSCRIPTOMIC ANALYSIS OF F344 RAT NASAL EPITHELIUM SUGGESTS THAT THE LACK OF CARCINOGENIC RESPONSE TO GLUTARALDEHYDE IS DUE TO ITS GREATER TOXICITY COMPARED TO FORMALDEHYDE

    Science.gov (United States)

    Formaldehyde is cytotoxic and carcinogenic to the rat nasal respiratory epithelium inducing tumors after 12 months. Glutaraldehyde is also cytotoxic but is not carcinogenic to nasal epithelium even after 24 months. Both aldehydes induce similar acute and subchronic histopathology...

  12. The UV Survey Mission Concept, CETUS

    Science.gov (United States)

    Heap, Sara; and the CETUS Team

    2018-01-01

    In March 2017, NASA selected CETUS for study of a Probe-class mission concept. W. Danchi is the CETUS PI, and S. Heap is the Science PI. CETUS is primarily a UV survey telescope to complement survey telescopes of the 2020’s including E-ROSITA, Subaru Hyper Suprime Cam and Prime-Focus Spectrograph, WFIRST, and the Square Kilometer Array. CETUS comprises a 1.5-m wide-field telescope and three science instruments: a wide-field (1045” on a side) far-UV and near-UV camera; a similarly wide-field near-UV multi-object spectrograph utilizing a next-generation micro-shutter array; and a single-object spectrograph with options of spectral region (far-UV or near-UV) and spectral resolving power (2,000 or 40,000). The survey instruments will operate simultaneously thereby producing wide-field images in the near-UV and far-UV and a spectrogram containing near-UV spectra of up to 100 sources free of spectral overlap and astronomical background. ln concert with other survey telescopes, CETUS will focus on understanding galaxy evolution at cosmic noon (z~1-2).

  13. Tooth bleaching using peroxide-containing agents: current status of safety issues.

    Science.gov (United States)

    Li, Y

    1998-08-01

    During the last 10 years, at-home tooth bleaching using peroxide-containing agents has quickly become well accepted. It is one of the most popular cosmetic dental procedures for whitening teeth. Although there are few disputes regarding their efficacy, concerns and debates have continued regarding the safety of peroxide-containing tooth bleaching agents. Potential carcinogenicity and genotoxicity of the peroxides used in bleaching agents are the two most persistent and controversial issues. This article reviews and discusses available information on carcinogenicity and genotoxicity of hydrogen peroxide and the potential risks associated with the use of peroxide-containing bleaching agents. Clinical studies reported after the 1996 international symposium on responses of oral tissues to peroxide-containing bleaching agents are also reviewed. Overall evidence supports the conclusion that the proper use of peroxide-containing at-home tooth bleaching agents is safe. However, potential adverse effects may occur in inappropriate applications, abuses, or the use of inappropriate products. At-home tooth bleaching should be monitored by dental professionals to maximize the benefits while minimizing potential risks.

  14. New technologies for UV detectors

    Science.gov (United States)

    Joseph, C. L.

    1993-01-01

    Several technologies are currently being developed, leading to substantial improvements in the performance of UV detectors or significant reductions in power or weight. Four technologies discussed are (1) thin-film coatings to enhance the UV sensitivity of CCD's, (2) highly innovative magnet assemblies that dramatically reduce weight and result in virtually no external flux, (3) new techniques for curving microchannel plates (MCP's) so that single plates can be used to prevent ion feedback and present highly localized charge clouds to an anode structure, and (4) high-performance alternatives to glass-based MCP's. In item (2), for example, very robust magnets are made out of rare earth materials such as samarium cobalt, and cladding magnets are employed to prevent flux from escaping from the detector into the external environment. These new ultralight magnet assemblies are able to create strong, exceptionally uniform magnetic fields for image intensification and focusing of photoelectrons. The principle advantage of such detectors is the quantum efficiencies of 70-80 percent obtained throughout ultraviolet wavelengths (900-2000 A), the highest of any device. Despite the improvements achieved under item (3), high-performance alternatives to conventional glass-based MCP's potentially offer three distinct new advantages that include (1) a 30-100-fold improvement in dynamic range resulting in correspondingly higher signal-to-noise ratios, (2) the use of pure dielectric and semiconductor materials that will not outgas contaminants that eventually destroy photocathodes, and (3) channels that have constant spacing providing long-ranged order since the plates are made using photolithography techniques from the semiconductor industry. The manufacturers of these advanced-technology MCP's, however, are a couple of years away from actually producing a functioning image intensifier. In contrast to the use of CCD's for optical, ground based observations, there is no single

  15. Synthesis and evaluation of novel caged DNA alkylating agents bearing 3,4-epoxypiperidine structure.

    Science.gov (United States)

    Kawada, Yuji; Kodama, Tetsuya; Miyashita, Kazuyuki; Imanishi, Takeshi; Obika, Satoshi

    2012-07-14

    Previously, we reported that the 3,4-epoxypiperidine structure, whose design was based on the active site of DNA alkylating antitumor antibiotics, azinomycins A and B, possesses prominent DNA cleavage activity. In this report, novel caged DNA alkylating agents, which were designed to be activated by UV irradiation, were synthesized by the introduction of four photo-labile protecting groups to a 3,4-epoxypiperidine derivative. The DNA cleavage activity and cytotoxicity of the caged DNA alkylating agents were examined under UV irradiation. Four caged DNA alkylating agents showed various degrees of bioactivity depending on the photosensitivity of the protecting groups.

  16. Comparison of UV action spectra for lethality and mutation in Salmonella typhimurium using a broad band source and monochromatic radiations

    International Nuclear Information System (INIS)

    Calkins, John; Selby, Christopher; Enoch, H.G.

    1987-01-01

    The UV-B region (280-320 nm) is thought to be primarily responsible for the mutagenic, lethal, and carcinogenic effects of solar radiation. We have conducted UV-B action spectroscopy for mutagenesis and survival of Ames' Salmonella typhimurium strain TA98 (uvrB, pKM101) using both monochromatic radiation from a dye laser and broader bandwidth radiation emitted from FS-20 sunlamps. A series of optical filters having different transmission cut-offs together with the sunlamp source provided bandwidths having successively less short wavelength components from which a ''broad band'' action spectrum was deduced. The two sets of action spectra differed both qualitatively and quantitatively: in comparison to the monochromatic action spectra, the ''broad band'' spectra showed up to a 200-fold reduced efficiency for both mutation induction and lethality by UV-B wavelengths. These results suggest a large protective effect of the background UV-A and/or visible radiations which were present during the broad spectrum irradiations and which are also present in solar radiation. Additional experiments show that to the extent tested this protective effect is not due to photo-reactivation or irradiance (dose rate) effects. (author)

  17. A Structure Identification and Toxicity Assessment of the Degradation Products of Aflatoxin B₁ in Peanut Oil under UV Irradiation.

    Science.gov (United States)

    Mao, Jin; He, Bing; Zhang, Liangxiao; Li, Peiwu; Zhang, Qi; Ding, Xiaoxia; Zhang, Wen

    2016-11-12

    Aflatoxins, a group of extremely hazardous compounds because of their genotoxicity and carcinogenicity to human and animals, are commonly found in many tropical and subtropical regions. Ultraviolet (UV) irradiation is proven to be an effective method to reduce or detoxify aflatoxins. However, the degradation products of aflatoxins under UV irradiation and their safety or toxicity have not been clear in practical production such as edible oil industry. In this study, the degradation products of aflatoxin B₁ (AFB₁) in peanut oil were analyzed by Ultra Performance Liquid Chromatograph-Thermo Quadrupole Exactive Focus mass spectrometry/mass spectrometry (UPLC-TQEF-MS/MS). The high-resolution mass spectra reflected that two main products were formed after the modification of a double bond in the terminal furan ring and the fracture of the lactone ring, while the small molecules especially nitrogen-containing compound may have participated in the photochemical reaction. According to the above results, the possible photodegradation pathway of AFB₁ in peanut oil is proposed. Moreover, the human embryo hepatocytes viability assay indicated that the cell toxicity of degradation products after UV irradiation was much lower than that of AFB₁, which could be attributed to the breakage of toxicological sites. These findings can provide new information for metabolic pathways and the hazard assessment of AFB₁ using UV detoxification.

  18. A Structure Identification and Toxicity Assessment of the Degradation Products of Aflatoxin B1 in Peanut Oil under UV Irradiation

    Directory of Open Access Journals (Sweden)

    Jin Mao

    2016-11-01

    Full Text Available Aflatoxins, a group of extremely hazardous compounds because of their genotoxicity and carcinogenicity to human and animals, are commonly found in many tropical and subtropical regions. Ultraviolet (UV irradiation is proven to be an effective method to reduce or detoxify aflatoxins. However, the degradation products of aflatoxins under UV irradiation and their safety or toxicity have not been clear in practical production such as edible oil industry. In this study, the degradation products of aflatoxin B1 (AFB1 in peanut oil were analyzed by Ultra Performance Liquid Chromatograph-Thermo Quadrupole Exactive Focus mass spectrometry/mass spectrometry (UPLC-TQEF-MS/MS. The high-resolution mass spectra reflected that two main products were formed after the modification of a double bond in the terminal furan ring and the fracture of the lactone ring, while the small molecules especially nitrogen-containing compound may have participated in the photochemical reaction. According to the above results, the possible photodegradation pathway of AFB1 in peanut oil is proposed. Moreover, the human embryo hepatocytes viability assay indicated that the cell toxicity of degradation products after UV irradiation was much lower than that of AFB1, which could be attributed to the breakage of toxicological sites. These findings can provide new information for metabolic pathways and the hazard assessment of AFB1 using UV detoxification.

  19. A Structure Identification and Toxicity Assessment of the Degradation Products of Aflatoxin B1 in Peanut Oil under UV Irradiation

    Science.gov (United States)

    Mao, Jin; He, Bing; Zhang, Liangxiao; Li, Peiwu; Zhang, Qi; Ding, Xiaoxia; Zhang, Wen

    2016-01-01

    Aflatoxins, a group of extremely hazardous compounds because of their genotoxicity and carcinogenicity to human and animals, are commonly found in many tropical and subtropical regions. Ultraviolet (UV) irradiation is proven to be an effective method to reduce or detoxify aflatoxins. However, the degradation products of aflatoxins under UV irradiation and their safety or toxicity have not been clear in practical production such as edible oil industry. In this study, the degradation products of aflatoxin B1 (AFB1) in peanut oil were analyzed by Ultra Performance Liquid Chromatograph-Thermo Quadrupole Exactive Focus mass spectrometry/mass spectrometry (UPLC-TQEF-MS/MS). The high-resolution mass spectra reflected that two main products were formed after the modification of a double bond in the terminal furan ring and the fracture of the lactone ring, while the small molecules especially nitrogen-containing compound may have participated in the photochemical reaction. According to the above results, the possible photodegradation pathway of AFB1 in peanut oil is proposed. Moreover, the human embryo hepatocytes viability assay indicated that the cell toxicity of degradation products after UV irradiation was much lower than that of AFB1, which could be attributed to the breakage of toxicological sites. These findings can provide new information for metabolic pathways and the hazard assessment of AFB1 using UV detoxification. PMID:27845743

  20. UV-extending Ghost Inflation

    CERN Document Server

    Ivanov, Mikhail M

    2014-01-01

    We present a setup that provides a partial UV-completion of the ghost inflation model up to a scale which can be almost as high as the Planck mass. This is achieved by coupling the inflaton to the Lorentz-violating sector described by the Einstein-aether theory or its khronometric version. Compared to previous works on ghost inflation our setup allows to go beyond the study of small perturbations and include the background dynamics in a unified framework. In the specific regime when the expansion of the Universe is dominated by the kinetic energy of the inflaton we find that the model predicts rather high tensor-to-scalar ratio r ~ 0.02 $\\div$ 0.2 and non-Gaussianity of equilateral type with f_NL in the range from -50 to -5.

  1. Beneficial and adverse effects of chemopreventive agents

    International Nuclear Information System (INIS)

    Lee, Byung Mu; Park, Kwang-Kyun

    2003-01-01

    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

  2. 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.

  3. Induction of DNA deletions after UV-light irradiation in yeast Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Stepanova, A.N.; Koltovaya, N.A.

    2008-01-01

    We study mutagenic action of such a damaging agent as UV light, which can lead to DNA double-strand breaks (DSB). DNA deletions and gross rearrangements occur in process of DSB repair. We show that UV light induces deletion and rearrangement very efficiently. Analysis of efficacy of different types of repair shows that cell tries to repair DSBs with a combination of both homologous recombination (HR) and nonhomologous end joining (NHEJ) if available and that DSB repair by HR is more effective than by NHEJ in growing culture of haploid yeast

  4. DNA repair of UV photoproducts and mutagenesis in human mitochondrial DNA

    International Nuclear Information System (INIS)

    Pascucci, B.; Dogliotti, E.; Versteegh, A.; Hoffen, A. van; Zeeland, A.A. van; Mullenders, L.H.F.

    1997-01-01

    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 GL 1 ) of the NciI site). Conversely, an approximately tenfold increase over background mutation frequency was recorded after cell exposure to 20 J/m 2 . In this case, the majority of mutations were C > T transitions preferentially located on the non-transcribed DNA strand at C 1 and C 2 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)

  5. 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.

  6. 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

  7. Effect of UV-C irradiation on growth, sporulation and pathogenicity of cochliobolus sativus isolates

    International Nuclear Information System (INIS)

    Jawhar, M.; Arabi, M.I.E.

    1999-12-01

    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/cm 2 . 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)

  8. The participation of the Fanconi anemia pathway in the replication of UV-damage DNA

    International Nuclear Information System (INIS)

    Federico, M.B.; Vallerga, M.B.; Mansilla, S.F.; Speroni, J.; Habif, M.; D'Alessio, C.; Gottifredi, V.

    2011-01-01

    When cells are challenged with genotoxic agents, replicating cells must use damaged DNA as templates. In this way, active replication forks do not collapse and cell viability is protected. After UV irradiation a specialized DNA polymerase pol eta uses UV damaged DNA as template. Intriguingly, Pol eta lost in human cells does not steeply increase UV sensitivity. This suggests that compensatory mechanisms promote cell survival when pol eta is absent. We have found an increase and sustained FANCD2 ubiquitination and focal formation after UV irradiation when pol eta is lost. FANCD2 is a key marker of the activation of the FANCONI ANEMIA (FA) pathway. While there is limited information regarding a role of the FA pathway after UV irradiation, it is well established that FANCD2 ubiquitination is linked to the recruitment of homologous recombination (HR) specific markers to other lesions. We therefore thought that cell viability in the absence of pol eta might result from the activation of FANDC2-dependent HR at collapsed replication forks. We are currently analyzing markers of damage such as γH2AX phosphorylation, markers of HR such as Rad51, markers of double strand breaks accumulation such as 53BP1 and setting up viability assays. This information might allow us to predict if FANCD2 can trigger HR after UV and if this contributes to cell viability when pol eta is absent. (authors)

  9. Sensitivity of pathogenic and free-living Leptospira spp. to UV radiation and mitomycin C

    International Nuclear Information System (INIS)

    Stamm, L.V.; Charon, N.W.

    1988-01-01

    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

  10. 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.

  11. Mechanism of Cuticle Hole Development in Human Hair Due to UV-Radiation Exposure

    Directory of Open Access Journals (Sweden)

    Kazuhisa Maeda

    2018-03-01

    Full Text Available Hair is easily damaged by ultraviolet (UV radiation, bleaching agents or permanent wave treatments, and as damage progresses, hair loses its gloss, develops split ends and breaks. However, the causes of hair damage due to UV radiation have not yet been clarified. We discovered that in one mechanism facilitating damage to wet hair by UV radiation, the unsaturated fatty acids in wet hair produce hydroxy radicals upon exposure to UV radiation, and these radicals produce cuticle holes between the cuticle layers. In wet hair exposed to UV radiation, cuticle holes were produced only between the cuticle layers, whereas when human hair was immersed in a solution containing hydroxy radicals produced by Fenton’s reaction, a random production of cuticle holes was noted. It is thought that hydroxy radicals are produced only between the cuticle layers by exposure to UV radiation, and cuticle holes are formed only in this region because one of the polyunsaturated fatty acids, linoleic acid, with a bis-allyl hydrogen, is found between the cuticle layers.

  12. Expression of UV-irradiated adenovirus in normal and UV-sensitive Chinese hamster ovary cells

    International Nuclear Information System (INIS)

    Rainbow, A.J.

    1985-01-01

    The chinese hamster ovary (CHO) cell mutants UV-20, UV-24, and UV-41 are abnormally sensitive to UV and harbour various defects lin their ability to repair cellular DNA. This study has examined the expression of UV-irradiated AD2 in these cells. HCR of UV-irradiated Ad2, as measured by viral structural antigen (Vag) formation or progeny production, was found to be similar for the normal and the UV-sensitive CHO strains. UV-irradiation of Ad2 (1200 J/m/sup 2/) resulted in a delay of Vag expression of 18 hours in normal human fibroblasts, which is thought to reflect the time required for removal of UV-induced lesions from the DNA before viral DNA synthesis can proceed. However, a similar UV-irradiation of Ad2 did not result in a delay of Vag expression for infection of CHO cells, suggesting that UV-induced lesions in Ad2 DNA do not inhibit its replication in CHO cells. These results indicate a fundamental difference in the processing of UV-irradiated AD2-DNA in CHO as compared to human cells

  13. Radiopharmaceutical scanning agents

    International Nuclear Information System (INIS)

    1976-01-01

    This invention is directed to dispersions useful in preparing radiopharmaceutical scanning agents, to technetium labelled dispersions, to methods for preparing such dispersions and to their use as scanning agents

  14. Taskable Reactive Agent Communities

    National Research Council Canada - National Science Library

    Myers, Karen

    2002-01-01

    The focus of Taskable Reactive Agent Communities (TRAC) project was to develop mixed-initiative technology to enable humans to supervise and manage teams of agents as they perform tasks in dynamic environments...

  15. Natural agents: cellular and molecular mechanisms of photoprotection.

    Science.gov (United States)

    Afaq, Farrukh

    2011-04-15

    The skin is the largest organ of the body that produces a flexible and self-repairing barrier and protects the body from most common potentially harmful physical, environmental, and biological insults. Solar ultraviolet (UV) radiation is one of the major environmental insults to the skin and causes multi-tiered cellular and molecular events eventually leading to skin cancer. The past decade has seen a surge in the incidence of skin cancer due to changes in life style patterns that have led to a significant increase in the amount of UV radiation that people receive. Reducing excessive exposure to UV radiation is desirable; nevertheless this approach is not easy to implement. Therefore, there is an urgent need to develop novel strategies to reduce the adverse biological effects of UV radiation on the skin. A wide variety of natural agents have been reported to possess substantial skin photoprotective effects. Numerous preclinical and clinical studies have elucidated that natural agents act by several cellular and molecular mechanisms to delay or prevent skin cancer. In this review article, we have summarized and discussed some of the selected natural agents for skin photoprotection. Copyright © 2010 Elsevier Inc. All rights reserved.

  16. Chemical characteristic of PM2.5 emission and inhalational carcinogenic risk of domestic Chinese cooking

    International Nuclear Information System (INIS)

    Zhang, Nan; Han, Bin; He, Fei; Xu, Jia; Zhao, Ruojie; Zhang, Yujuan; Bai, Zhipeng

    2017-01-01

    To illustrate chemical characteristic of PM 2.5 emission and assess inhalational carcinogenic risk of domestic Chinese cooking, 5 sets of duplicate cooking samples were collected, using the most used 5 types of oil. The mass abundance of 14 elements, 5 water-soluble ions, organic carbon (OC), elemental carbon (EC) and 11 polycyclic aromatic hydrocarbons (PAHs) were calculated; the signature and diagnostic ratio of cooking in the domestic kitchen were analyzed; and carcinogenic risks of heavy metals and PAHs via inhalation were assessed in two scenarios. The analysis showed that OC was the primary composition in the chemical profile; Na was the most abundant element that might be due to the usage of salt; Cr and Pb, NO 3 − and SO 4 2- , Phe, FL and Pyr were the main heavy metals/water-soluble ions/PAHs, respectively. Phe and FL could be used to separate cooking and stationary sources, while diagnostic ratios of BaA/(BaA + CHR), BaA/CHR, BaP/BghiP and BaP/BeP should be applied with caution, as they were influenced by various cooking conditions. Carcinogenic risks of heavy metals and PAHs were evaluated in two scenarios, simulating the condition of cooking with no ventilation and with the range hood on, respectively. The integrated risk of heavy metals and PAHs was 2.7 × 10 −3 and 5.8 × 10 −6 , respectively, during cooking with no ventilation. While with the usage of range hood, only Cr(VI), As and Ni might induce potential carcinogenic risk. The difference in the chemical abundance in cooking sources found between this and other studies underlined the necessity of constructing locally representative source profiles under real conditions. The comparison of carcinogenic risk suggested that the potentially adverse health effects induced by inorganic compositions from cooking sources should not be ignored. Meanwhile, intervention methods, such as the operation of range hood, should be applied during cooking for health protection. - Highlights: • PM 2

  17. Micropollutants removal by full-scale UV-C/sulfate radical based Advanced Oxidation Processes.

    Science.gov (United States)

    Rodríguez-Chueca, J; Laski, E; García-Cañibano, C; Martín de Vidales, M J; Encinas, Á; Kuch, B; Marugán, J

    2018-07-15

    The high chemical stability and the low biodegradability of a vast number of micropollutants (MPs) impede their correct treatment in urban wastewater treatment plants. In most cases, the chemical oxidation is the only way to abate them. Advanced Oxidation Processes (AOPs) have been experimentally proved as efficient in the removal of different micropollutants at lab-scale. However, there is not enough information about their application at full-scale. This manuscript reports the application of three different AOPs based on the addition of homogeneous oxidants [hydrogen peroxide, peroxymonosulfate (PMS) and persulfate anions (PS)], in the UV-C tertiary treatment of Estiviel wastewater treatment plant (Toledo, Spain) previously designed and installed in the facility for disinfection. AOPs based on the photolytic decomposition of oxidants have been demonstrated as more efficient than UV-C radiation alone on the removal of 25 different MPs using low dosages (0.05-0.5 mM) and very low UV-C contact time (4-18 s). Photolysis of PMS and H 2 O 2 reached similar average MPs removal in all the range of oxidant dosages, obtaining the highest efficiency with 0.5 mM and 18 s of contact time (48 and 55% respectively). Nevertheless, PMS/UV-C reached slightly higher removal than H 2 O 2 /UV-C at low dosages. So, these treatments are selective to degrade the target compounds, obtaining different removal efficiencies for each compound regarding the oxidizing agent, dosages and UV-C contact time. In all the cases, H 2 O 2 /UV-C is more efficient than PMS/UV-C, comparing the ratio cost:efficiency (€/m 3 ·order). Even H 2 O 2 /UV-C treatments are more efficient than UV-C alone. Thus, the addition of 0.5 mM of H 2 O 2 compensates the increased of UV-C contact time and therefore the increase of electrical consumption, that it should be need to increase the removal of MPs by UV-C treatments alone. Copyright © 2018 Elsevier B.V. All rights reserved.

  18. Occupational exposure to biological agents intentionally used in Polish enterprises

    Directory of Open Access Journals (Sweden)

    Anna Kozajda

    2015-02-01

    Full Text Available Background: The paper presents the intentional use of biological agents for industrial, diagnostic and research purposes in Polish enterprises. Material and Methods: The National Register of Biological Agents (Krajowy Rejestr Czynników Biologicznych – KRCB is an online database that collects the data on the intentional use of biological agents at work in Poland. Results: As of December 2013 there were 533 notifications in KRCB, mainly for diagnostic (73%, research (20% and industrial purposes (7%. Mostly there were hospital diagnostic laboratories (37%, and other laboratories (35%, as well as higher education and research institutions (11%. In total, 4015 workers (91.7% of women, 8.3% of men were exposed to biological agents. Agents classified in risk group 2 were used in 518 enterprises, and in risk group 3 in 107 enterprises. Of those agents the following bacteria were the most frequently used: Escherichia coli except for non-pathogenic strains (455 enterprises and 3314 exposed workers; Staphylococcus aureus (445 and 3270; and Pseudomonas aeruginosa (406 and 2969, respectively. In 66 enterprises there were used biological agents recognized by the International Agency for Research on Cancer (IARC as carcinogens. They are viruses: Epstein-Barr (7 enterprises, 181 exposed workers; hepatitis B (16 and 257; hepatitis C virus (15 and 243; human immunodeficiency virus (8 and 107; human papillomaviruses (2 and 4; parasites: Clonorchis viverrini (1 and 2; Clonorchos sinensis (1 and 2; Schistosoma haematobium (1 and 2 and bacteria Helicobacter pylori (15 and 230, respectively. Conclusions: The National Register of Biological Agents at Work permits to evaluate the situation of occupational exposure to biological agents used intentionally in enterprises in Poland. Med Pr 2015;66(1:39–47

  19. 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...

  20. Asymptotically Optimal Agents

    OpenAIRE

    Lattimore, Tor; Hutter, Marcus

    2011-01-01

    Artificial general intelligence aims to create agents capable of learning to solve arbitrary interesting problems. We define two versions of asymptotic optimality and prove that no agent can satisfy the strong version while in some cases, depending on discounting, there does exist a non-computable weak asymptotically optimal agent.