WorldWideScience

Sample records for carcinogenic species emitted

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

    OpenAIRE

    Tennant, R W; Spalding, J.

    1996-01-01

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

  2. DIRECT-ACTING, DNA-DAMAGING AS (III)-METHYLATED SPECIES: IMPLICATIONS FOR A CARCINOGENIC MECHANISM OF ACTION OF ARSENICALS

    Science.gov (United States)

    Direct-acting, DNA-damaging As (III)-methylated species: implications for a carcinogenic . mechanism of action of arsenicals Inorganic arsenic (iAs, arsenite and arsenate) has been thought to act as a carcinogen without reacting directly with DNA; neither iAs nor the As(...

  3. [Mechanisms of action for metallic elements and their species classified carcinogen R 45 and R 49 by EU].

    Science.gov (United States)

    Apostoli, P; Catalani, S

    2008-01-01

    In this paper we will deal with mechanism of carcinogenic action of metallic elements and their species (arsenic, beryllium, cadmium, cobalt, chromium, nickel) identified by EU as carcinogen R 45 or R 49. The carcinogenic effect depended on the ability of to penetrate the cell and interacted with the target sites, therefore the state of oxidation, charging, the solubility, type of binding, stereochemistry and the ability to interact with other xenobiotics were crucial. The carcinogenic metallic elements classified R45 or R49 are essentially weak mutagen and do not form adducts with the DNA as initial step of their carcinogenicity In spite of the wide range of metallic elements physicochemical properties, some common general mechanisms of carcinogenesis emerge:from the induction of oxidative stress, to inhibition of DNA repair, from activation of mitogenic signalling, to epigenetic modification of gene expression. However, each species lead to specific molecular interactions and were subject to different bioavailability. It has been also strongly supported the hypothesis that the metallic elements may act as a co-carcinogen with other organic compounds, for example with PAH. PMID:19344091

  4. Species and diet related resistance to chemical carcinogens: biochemical mechanisms of aflatoxin B1 detoxification

    International Nuclear Information System (INIS)

    To provide insight into the biochemical mechanisms mediating species and diet related resistance to chemical carcinogens, the biotransformation and covalent binding to DNA of the potent hepatocarcinogen aflatoxin B1(AFB) was investigated in resistant and susceptible species fed standard and butylated hydroxyanisole (BHA)-supplemented diets. The rat is sensitive to the hepatocarcinogenic effects of AFB, whereas the mouse, and rats fed BHA-supplemented diet, are resistant. To differentiate between enzyme induction and direct antioxidant effects, BHA was administered to rats for 9 days, or as a single dose 4-7 hrs prior to i.p. injection of 3H-AFB. Long-term treatment with BHA doubled the biliary excretion of the glutathione conjugate of AFB and the AFP1-glucuronide, and reduced the binding of AFB to hepatic DNA to 16% of control. Single-dose BHA treatment had no effect. To determine if glutathione S-transferase (GST) activity towards the AFB-epoxide mediates both treatment and species related resistance to AFB carcinogenesis, a method was developed to measure the rate of formation of the AFB-epoxide, and the rate of inactivation of the epoxide via GST. To demonstrate the importance of GST-mediated detoxification of the AFB-epoxide in the mouse in vivo, depletion of hepatic GSH was accomplished by administration of L-buthionine-S,R-sulfoximine and diethyl maleate, prior to administration of AFB. GSH depletion was associated with a 30-fold increase in AFB-DNA binding

  5. A combination of 3D-QSAR, docking, local-binding energy (LBE) and GRID study of the species differences in the carcinogenicity of benzene derivatives chemicals.

    Science.gov (United States)

    Fratev, Filip; Benfenati, Emilio

    2008-09-01

    A combination of 3D-QSAR, docking, local-binding energy (LBE) and GRID methods was applied as a tool to study and predict the mechanism of action of 100 carcinogenic benzene derivatives. Two 3D-QSAR models were obtained: (i) model of mouse carcinogenicity on the basis of 100 chemicals (model 1) and (ii) model of the differences in mouse and rat carcinogenicity on the basis of 73 compounds (model 2). 3D-QSAR regression maps indicated the important differences in species carcinogenicity, and the molecular positions associated with them. In order to evaluate the role of P450 metabolic process in carcinogenicity, the following approaches were used. The 3D models of CYP2E1 for mouse and rat were built up. A docking study was applied and the important ligand-protein residues interactions and oxidation positions of the molecules were identified. A new approach for quantitative assessment of metabolism pathways was developed, which enabled us to describe the species differences in CYP2E1 metabolism, and how it can be related to differences in the carcinogenic potential for a subset of compounds. The binding energies of the important substituents (local-binding energy-LBE) were calculated, in order to quantitatively demonstrate the contribution of the substituents in metabolic processes. Furthermore, a computational procedure was used for determining energetically favourable binding sites (GRID examination) of the enzymes. The GRID procedure allowed the identification of some important differences, related to species metabolism in CYP2E1. Comparing GRID, 3D-QSAR maps and LBE results, a similarity was identified, indicating a relationship between P450 metabolic processes and the differences in the carcinogenicity. PMID:18495507

  6. Acrylamide carcinogenicity.

    Science.gov (United States)

    Klaunig, James E

    2008-08-13

    The induction of cancer by chemicals is a multiple-stage process. Acrylamide is carcinogenic to experimental mice and rats, causing tumors at multiple organ sites in both species when given in drinking water or by other means. In mice, acrylamide increased the incidence and multiplicity of lung tumors and skin tumors. In two bioassays in rats, acrylamide administered in drinking water consistently induced mesotheliomas of the testes, thyroid tumors, and mammary gland tumors. In addition, brain tumors appeared to be increased. In one of the rat bioassays, pituitary tumors, pheochromocytomas, uterine tumors, and pituitary tumors were noted. The conversion of acrylamide metabolically to the reactive, mutagenic, and genotoxic product, glycidamide, can occur in both rodent and humans. Glycidamide and frequently acrylamide have been positive for mutagenicity and DNA reactivity in a number of in vitro and in vivo assays. The effects of chronic exposure of glycidamide to rodents have not been reported. Epidemiologic studies of workers for possible health effects from exposures to acrylamide have not shown a consistent increase in cancer risk. Although an increase in the risk for pancreatic cancer (almost double) was seen in highly exposed workers, no exposure response relationship could be determined. The mode of action remains unclear for acrylamide-induced rodent carcinogenicity, but support for a genotoxic mechanism based on in vitro and in vivo DNA reactivity assays cannot be ruled out. In addition, the pattern of tumor formation in the rat following chronic exposure supports a genotoxic mode of action but also suggests a potential role of endocrine modification. PMID:18624430

  7. MESSENGER Searches for Less Abundant or Weakly Emitting Species in Mercury's Exosphere

    Science.gov (United States)

    Vervack, Ronald J., Jr.; McClintock, William E.; Killen, Rosemary M.; Sprague, Ann L.; Burger, Matthew H.; Merkel, Aimee W.; Sarantos, Menelaos

    2011-01-01

    Mercury's exosphere is composed of material that originates at the planet's surface, whether that material is native or delivered by the solar wind and micrometeoroids. Many exospheric species have been detected by remote sensing, including H and He by Mariner 10, Na, K, and Ca by ground-based observations, and H, Na, Ca, Mg, and Ca+ by the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft. Other exospheric species, including Fe, AI, Si, 0, S, Mn, CI, Ti, OH, and their ions, are expected to be present on the basis of MESSENGER surface measurements and models of Mercury's surface chemistry. Here we report on searches for these species made with the Ultraviolet and Visible Spectrometer (UVVS) channel of the Mercury Atmospheric and Surface Composition Spectrometer (MASCS). No obvious signatures of the listed species have yet been observed in Mercury's exosphere by the UVVS as of this writing. It is possible that detections are elusive because the optimum regions of the exosphere have not been sampled. The Sun-avoidance constraints on MESSENGER place tight limits on instrument boresight directions, and some regions are probed infrequently. If there are strong spatial gradients in the distribution of weakly emitting species, a high-resolution sampling of specific regions may be required to detect them. Summing spectra over time will also aid in the ability to detect weaker emission. Observations to date nonetheless permit strong upper limits to be placed on the abundances of many undetected species, in some cases as functions of time and space. As those limits are lowered with time, the absence of detections can provide insight into surface composition and the potential source mechanisms of exospheric material.

  8. Tunable and white light emitting AlPO{sub 4} mesoporous glass by design of inorganic/organic luminescent species

    Energy Technology Data Exchange (ETDEWEB)

    He, Jin; Li, Rihong, E-mail: lirihong@siom.ac.cn; Yuan, Xinqiang; Zhang, Long, E-mail: lzhang@siom.ac.cn [Key Laboratory of Materials for High Power Lasers, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); Wang, Yan [Key Laboratory of Materials for High Power Lasers, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Xu, Shiqing [College of Materials Science and Engineering, China Jiliang University, Hangzhou, Zhejiang 310018 (China)

    2015-04-01

    The realization of tunable and white light emitting sources employed by UV-LED with single-host phosphors has been an exciting development in the search for high luminous efficiency and excellent color rendering index white-light source. A tunable and white light emitting mesoporous glass was prepared by utilizing both inorganic/organic (Europium/coumarin) luminescent species in the meso-structure. The tunable and white light emission was deliberately designed by CIE calculation based on the individual emission spectra, which was realized by tailoring the emission of Eu{sup 2+}/Eu{sup 3+} ions and coumarin 535 in sol-gel AlPO{sub 4} mesoporous glass. This simple and versatile procedure is not limited in the combination of rare earth and organic dye and is therefore extendable to other luminescent species in meso-structure for color-tunable efficient solid-state lighting sources.

  9. Tunable and white light emitting AlPO4 mesoporous glass by design of inorganic/organic luminescent species

    Directory of Open Access Journals (Sweden)

    Jin He

    2015-04-01

    Full Text Available The realization of tunable and white light emitting sources employed by UV-LED with single-host phosphors has been an exciting development in the search for high luminous efficiency and excellent color rendering index white-light source. A tunable and white light emitting mesoporous glass was prepared by utilizing both inorganic/organic (Europium/coumarin luminescent species in the meso-structure. The tunable and white light emission was deliberately designed by CIE calculation based on the individual emission spectra, which was realized by tailoring the emission of Eu2+/Eu3+ ions and coumarin 535 in sol-gel AlPO4 mesoporous glass. This simple and versatile procedure is not limited in the combination of rare earth and organic dye and is therefore extendable to other luminescent species in meso-structure for color-tunable efficient solid-state lighting sources.

  10. Application of head-space solid-phase microextraction for the analysis of volatile metabolites emitted by Penicillium species

    DEFF Research Database (Denmark)

    Nilsson, Torben; Larsen, Thomas Ostenfeld; Montanarella, Luca; Madsen, Jørgen Øgaard

    1996-01-01

    Head-space solid-phase microextraction (HS-SPME) has been used to collect volatile organic compounds (VOCs) emitted from fungi of the genus Penicillium. Gas chromatography combined with mass spectrometry (GC-MS) was employed for the analysis of the profiles of volatile metabolites characteristic...... for each species. The results obtained by HS-SPME compared favourably with those obtained by Tenax adsorption. The following characteristic metabolites were detected: isopentyl alcohol, 1-octene-3-ol, 3-octanone, 3-octanol, 2-methylisoborneol and geosmin, together with the not previously reported......, HS-SPME has a great potential use in the analysis of biogenic VOC emissions, including chemotaxonomical studies....

  11. Rodent Carcinogenicity Dataset

    OpenAIRE

    Fjodorova, Natalja; Novič, Marjana

    2013-01-01

    The rodent carcinogenicity dataset was compiled from the Carcinogenic Potency Database (CPDBAS) and was applied for the classification of quantitative structure-activity relationship (QSAR) models for the prediction of carcinogenicity based on the counter-propagation artificial neural network (CP ANN) algorithm. The models were developed within EU-funded project CAESAR for regulatory use. The dataset contains the following information: common information about chemicals (ID, chemical name, an...

  12. Size distribution of trace organic species emitted from biomass combustion and meat charbroiling

    Science.gov (United States)

    Kleeman, Michael J.; Robert, Michael A.; Riddle, Sarah G.; Fine, Philip M.; Hays, Michael D.; Schauer, James J.; Hannigan, Michael P.

    Size-resolved particulate matter emissions from pine, California oak, east coast oak, eucalyptus, rice straw, cigarette smoke, and meat cooking were analyzed for trace organic species using solvent-extraction followed by GC-MS analysis. Six particle size fractions were studied between 0.056, 0.1, 0.18, 0.32, 0.56, 1.0, and 1.8 μm particle diameter. The smallest particle size fraction analyzed was in the ultrafine (Dp0.9) with the size distribution of particle-phase organic carbon (OC) and/or elemental carbon (EC). The only organic compounds besides PAHs detected in the ultrafine size fraction of rice straw and cigarette smoke were benz[ de]anthracen-7-one (0.19 mg kg -1 rice straw burned) and 4-methylphenylacetone (2.64 mg cigarette -1), respectively. Caffeine was measured in cigarette smoke size fractions >0.1 μm with a total PM 1.8 emissions rate of 1 (mg cigarette -1). The most abundant organic species measured in meat cooking smoke was cholesterol with a size distribution that was highly correlated with both OC and EC. The concentration of each compound normalized by the concentration of total OC was relatively uniform for all particle sizes. Cholesterol and levoglucosan should prove to be useful tracers for meat cooking and wood smoke emissions in the ultrafine size range.

  13. The role of reactive oxygen species (ROS and cytochrome P-450 2E1 in the generation of carcinogenic etheno-DNA adducts

    Directory of Open Access Journals (Sweden)

    Kirsten Linhart

    2014-01-01

    Full Text Available Exocyclic etheno-DNA adducts are mutagenic and carcinogenic and are formed by the reaction of lipidperoxidation (LPO products such as 4-hydoxynonenal or malondialdehyde with DNA bases. LPO products are generated either via inflammation driven oxidative stress or via the induction of cytochrome P-450 2E1 (CYP2E1. In the liver CYP2E1 is induced by various compounds including free fatty acids, acetone and ethanol. Increased levels of CYP2E1 and thus, oxidative stress are observed in the liver of patients with non-alcoholic steatohepatitis (NASH as well as in the chronic alcoholic. In addition, chronic ethanol ingestion also increases CYP2E1 in the mucosa of the oesophagus and colon. In all these tissues CYP2E1 correlates significantly with the levels of carcinogenic etheno-DNA adducts. In contrast, in patients with non-alcoholic steatohepatitis (NASH hepatic etheno-DNA adducts do not correlate with CYP2E1 indicating that in NASH etheno-DNA adducts formation is predominately driven by inflammation rather than by CYP2E1 induction. Since etheno-DNA adducts are strong mutagens producing various types of base pair substitution mutations as well as other types of genetic damage, it is strongly believed that they are involved in ethanol mediated carcinogenesis primarily driven by the induction of CYP2E1.

  14. Thermotolerance of Leaf Discs from Four Isoprene-Emitting Species Is Not Enhanced by Exposure to Exogenous Isoprene1

    Science.gov (United States)

    Logan, Barry A.; Monson, Russell K.

    1999-01-01

    The effects of exogenously supplied isoprene on chlorophyll fluorescence characteristics were examined in leaf discs of four isoprene-emitting plant species, kudzu (Pueraria lobata [Willd.] Ohwi.), velvet bean (Mucuna sp.), quaking aspen (Populus tremuloides Michx.), and pussy willow (Salix discolor Muhl). Isoprene, supplied to the leaves at either 18 μL L−1 in compressed air or 21 μL L−1 in N2, had no effect on the temperature at which minimal fluorescence exhibited an upward inflection during controlled increases in leaf-disc temperature. During exposure to 1008 μmol photons m−2 s−1 in an N2 atmosphere, 21 μL L−1 isoprene had no effect on the thermally induced inflection of steady-state fluorescence. The maximum quantum efficiency of photosystem II photochemistry decreased sharply as leaf-disc temperature was increased; however, this decrease was unaffected by exposure of leaf discs to 21 μL L−1 isoprene. Therefore, there were no discernible effects of isoprene on the occurrence of symptoms of high-temperature damage to thylakoid membranes. Our data do not support the hypothesis that isoprene enhances leaf thermotolerance. PMID:10398717

  15. Thermotolerance of leaf discs from four isoprene-emitting species is not enhanced by exposure to exogenous isoprene

    Science.gov (United States)

    Logan; Monson

    1999-07-01

    The effects of exogenously supplied isoprene on chlorophyll fluorescence characteristics were examined in leaf discs of four isoprene-emitting plant species, kudzu (Pueraria lobata [Willd.] Ohwi.), velvet bean (Mucuna sp.), quaking aspen (Populus tremuloides Michx.), and pussy willow (Salix discolor Muhl). Isoprene, supplied to the leaves at either 18 &mgr;L L-1 in compressed air or 21 &mgr;L L-1 in N2, had no effect on the temperature at which minimal fluorescence exhibited an upward inflection during controlled increases in leaf-disc temperature. During exposure to 1008 &mgr;mol photons m-2 s-1 in an N2 atmosphere, 21 &mgr;L L-1 isoprene had no effect on the thermally induced inflection of steady-state fluorescence. The maximum quantum efficiency of photosystem II photochemistry decreased sharply as leaf-disc temperature was increased; however, this decrease was unaffected by exposure of leaf discs to 21 &mgr;L L-1 isoprene. Therefore, there were no discernible effects of isoprene on the occurrence of symptoms of high-temperature damage to thylakoid membranes. Our data do not support the hypothesis that isoprene enhances leaf thermotolerance. PMID:10398717

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

    OpenAIRE

    Schmidt, Charlie

    2006-01-01

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

  17. Beryllium: genotoxicity and carcinogenicity

    International Nuclear Information System (INIS)

    Beryllium (Be) has physical-chemical properties, including low density and high tensile strength, which make it useful in the manufacture of products ranging from space shuttles to golf clubs. Despite its utility, a number of standard setting agencies have determined that beryllium is a carcinogen. Only a limited number of studies, however, have addressed the underlying mechanisms of the carcinogenicity and mutagenicity of beryllium. Importantly, mutation and chromosomal aberration assays have yielded somewhat contradictory results for beryllium compounds and whereas bacterial tests were largely negative, mammalian test systems showed evidence of beryllium-induced mutations, chromosomal aberrations, and cell transformation. Although inter-laboratory differences may play a role in the variability observed in genotoxicity assays, it is more likely that the different chemical forms of beryllium have a significant effect on mutagenicity and carcinogenicity. Because workers are predominantly exposed to airborne particles which are generated during the machining of beryllium metal, ceramics, or alloys, testing of the mechanisms of the mutagenic and carcinogenic activity of beryllium should be performed with relevant chemical forms of beryllium

  18. Carcinogenic risks of radiations

    International Nuclear Information System (INIS)

    Ionising radiations are known since the end of the 19th century. Early, after being discovered, they were applied in Medicine and the association with an increased number of different malignant tumors was proved. This paper presents a literature review concerning epidemiological proof of radiation induced cancer, molecular mechanisms and factors that increase or decrease the carcinogenic action of ionizing radiations

  19. Chemical mechanisms of the interaction between radiation and chemical carcinogens

    International Nuclear Information System (INIS)

    There is evidence to suggest that ionizing radiation and chemical carcinogens can act synergistically to produce deleterious biological effects. In addition, many carcinogens undergo metabolic activation in vivo. This activation, initiated by biochemical redox reactions, can be simulated chemically, electrochemically, photochemically and radiation chemically. The principal reactive species formed by the action of ionizing radiation on aqueous solutions of macromolecules and mammalian cells, are hydroxyl radicals and superoxide anions. Pulse and steady-state radiolysis studies of model chemical systems have established that these species can 'activate' chemical carcinogens by a radical oxidation process, and that the resulting activated carcinogens can subsequently react with nucleophilic sites on DNA and other potential target macromolecules. Rate constants for some of the fast reactions involved in the radiation activation of carcinogens and in the subsequent carcinogen-DNA interactions have been determined, together with the yields of radiation-induced covalent DNA-carcinogen binding. A redox models for radiation-induced chemical carcinogenesis is proposed which describes a possible mechanism of action involving free radical species generated in the aqueous cellular milieu, which diffuse to and react with carcinogens located within the micro-environment of the cell. Preliminary experiments suggest that protection against radiation and chemical carcinogenesis can be achieved by radical scavenging or by competitive free radical inhibition

  20. Light Emitting Diode-Generated Blue Light Modulates Fibrosis Characteristics: Fibroblast Proliferation, Migration Speed, and Reactive Oxygen Species Generation

    Science.gov (United States)

    Mamalis, Andrew; Garcha, Manveer; Jagdeo, Jared

    2016-01-01

    Background and Objective Blue light is part of the visible light spectrum that does not generate harmful DNA adducts associated with skin cancer and photoaging, and may represent a safer therapeutic modality for treatment of keloid scars and other fibrotic skin diseases. Our laboratory previously demonstrated that light-emitting diode (LED) red and infrared light inhibits proliferation of skin fibroblasts. Moreover, different wavelengths of light can produce different biological effects. Furthermore, the effects of LED blue light (LED-BL) on human skin fibroblasts are not well characterized. This study investigated the effects of LED-BL on human skin fibroblast proliferation, viability, migration speed, and reactive oxygen-species (ROS) generation. Methods and Materials Irradiation of adult human skin fibroblasts using commercially-available LED-BL panels was performed in vitro, and modulation of proliferation and viability was quantified using the trypan blue dye exclusion assay, migratory speed was assessed using time-lapse video microscopy, and intracellular ROS generation was measured using the dihydrorhodamine flow cytometry assay. Statistical differences between groups were determined by ANOVA and Student s t-test. Results Human skin fibroblasts treated with LED-BL fluences of 5, 30, 45, and 80 J/cm2 demonstrated statistically significant dose-dependent decreases in relative proliferation of 8.4%, 29.1%, 33.8%, 51.7%, and 55.1%, respectively, compared to temperature and environment matched bench control plates, respectively. LED-BL fluences of 5, 30, 45 and 80 J/cm2 decreased fibroblast migration speed to 95 ± 7.0% (p = 0.64), 81.3 ± 5.5% (p = 0.021), 48.5 ± 2.7% (p migration speed, and is associated with increased reactive oxygen species generation in a dose-dependent manner without altering viability. LED-BL has the potential to contribute to the treatment of keloids and other fibrotic skin diseases and is worthy of further translational and clinical

  1. Chemistry of carcinogenic metals.

    OpenAIRE

    Martell, A E

    1981-01-01

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

  2. The carcinogenicity of chromium

    OpenAIRE

    Norseth, Tor

    1981-01-01

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

  3. Carcinogen risk assessment

    International Nuclear Information System (INIS)

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

  4. 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...... adducts with DNA. Adducts with 2-deoxyguanosine have been characterized for a number of aminoimidazoazaarenes. Adducts with DNA have also been found in animals after exposure to these compounds. In \\:iw major metabolic detoxification pathways are ring hydroxylation followed by conjugation and conjugation...... of the exocyclic amino group. Estimations of human cancer risk have indicated that ingestion of food containing aminoimidazoazaarenes are of importance....

  5. Resveratrol Prevents High Fluence Red Light-Emitting Diode Reactive Oxygen Species-Mediated Photoinhibition of Human Skin Fibroblast Migration.

    Directory of Open Access Journals (Sweden)

    Andrew Mamalis

    Full Text Available Skin fibrosis is a significant medical problem that leads to a functional, aesthetic, and psychosocial impact on quality-of-life. Light-emitting diode-generated 633-nm red light (LED-RL is part of the visible light spectrum that is not known to cause DNA damage and is considered a safe, non-invasive, inexpensive, and portable potential alternative to ultraviolet phototherapy that may change the treatment paradigm of fibrotic skin disease.The goal of our study was to investigate the how reactive oxygen species (ROS free radicals generated by high fluence LED-RL inhibit the migration of skin fibroblasts, the main cell type involved in skin fibrosis. Fibroblast migration speed is increased in skin fibrosis, and we studied cellular migration speed of cultured human skin fibroblasts as a surrogate measure of high fluence LED-RL effect on fibroblast function. To ascertain the inhibitory role of LED-RL generated ROS on migration speed, we hypothesized that resveratrol, a potent antioxidant, could prevent the photoinhibitory effects of high fluence LED-RL on fibroblast migration speed.High fluence LED-RL generated ROS were measured by flow cytometry analysis using dihydrorhodamine (DHR. For purposes of comparison, we assessed the effects of ROS generated by hydrogen peroxide (H2O2 on fibroblast migration speed and the ability of resveratrol, a well known antioxidant, to prevent LED-RL and H2O2 generated ROS-associated changes in fibroblast migration speed. To determine whether resveratrol could prevent the high fluence LED-RL ROS-mediated photoinhibition of human skin fibroblast migration, treated cells were incubated with resveratrol at concentrations of 0.0001% and 0.001% for 24 hours, irradiated with high fluences LED-RL of 480, 640, and 800 J/cm2.High fluence LED-RL increases intracellular fibroblast ROS and decreases fibroblast migration speed. LED-RL at 480, 640 and 800 J/cm2 increased ROS levels to 132.8%, 151.0%, and 158.4% relative to matched

  6. Arsenic Is A Genotoxic Carcinogen

    Science.gov (United States)

    Arsenic is a recognized human carcinogen; however, there is controversy over whether or not it should be considered a genotoxic carcinogen. Many possible modes of action have been proposed on how arsenic induces cancer, including inhibiting DNA repair, altering methylation patter...

  7. Metabolic activation of chemical carcinogens to reactive electrophiles

    International Nuclear Information System (INIS)

    Ionizing radiations and ultraviolet light constitute the principal known physical carcinogens. Likewise, a great variety and large number of chemicals and over 50 DNA and RNA viruses comprise the known chemical and viral carcinogens. These three categories of carcinogenic agents include the great majority of extrinsic agents known to induce cancer in mammals. Man is clearly susceptible to the action of physical and chemical carcinogens and, indeed, was the first species in which the activities of some of these agents were demonstated. It seems certain that viral carcinogenic information is involved in the etiology of at least some human tumors, but ethical and methodological problems have made it difficult to obtain unequivocal data. Given the long availability of experimental carcinogens of these three classes, there is surprisingly little known of their interrelationships in the production of cancer in experimental animals. The objective of this brief review is to present some salient aspects of experimental chemical carcinogenesis and an analysis of how some of these features relate to the mechanisms of action of radiation carcinogens

  8. 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.

  9. 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.

  10. Oxidative Stress in the Carcinogenicity of Chemical Carcinogens

    International Nuclear Information System (INIS)

    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, 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

  11. Conversion of emitted dimethyl sulfide into eco-friendly species using low-temperature atmospheric argon micro-plasma system

    International Nuclear Information System (INIS)

    Highlights: ► Dimethyl sulfide (DMS) was fully decomposed by two-electrode Ar micro-plasma. ► The reaction of DMS/Ar resulted in forming solid compound and gaseous product. ► The C-, H- and S-containing solid compound was fixed on the quartz inner tube. ► The H2-, CS2-, and H2S-gaseous products were possibly recyclable and trapped. ► The dissociation mechanism and treatment efficiency of DMS were also discussed. - Abstract: A custom-made atmospheric argon micro-plasma system was employed to dissociate dimethyl sulfide (DMS) into a non-foul-smelling species. The proposed system takes the advantages of low energy requirement and non-thermal process with a constant flow rate at ambient condition. In the experiments, the compositions of DMS/argon plasma, the residual gaseous phases, and solid precipitates were respectively characterized using an optical emission spectrometer, various gas-phase analyzers, and X-ray photoemission spectroscopy. For 400 ppm DMS introduced into argon plasma with two pairs of electrodes (90 W), a complete decomposition of DMS was achieved; the DMS became converted into excited species such as C*, C2*, H*, and CH*. When gaseous products were taken away from the treatment area, the excited species tended to recombine and form stable compounds or species, which formed as solid particles and gaseous phases. The solid deposition was likely formed by the agglomeration of C-, H-, and S-containing species that became deposited on the quartz inner tube. For the residual gaseous phases, low-molecular-weight segments mostly recombined into relatively thermodynamic stable species, such as hydrogen, hydrogen sulfide, and carbon disulfide. The dissociation mechanism and treatment efficiency are discussed, and a treatment of converting DMS into H2-, CS2-, and H2S-dominant by-products is proposed.

  12. 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. PMID:23973663

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

    Science.gov (United States)

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

    2016-08-01

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

  14. Mercury from combustion sources: a review of the chemical species emitted and their transport in the atmosphere

    International Nuclear Information System (INIS)

    Different species of mercury have different physical/chemical properties and thus behave quite differentially in air pollution control equipment and in the atmosphere. In general, emission of mercury from coal combustion sources are approximately 20-50% elemental mercury (Hg0) and 50-80% divalent mercury (Hg(II)), which may be predominantly HgCl2. Emissions of mercury from waste incinerators are approximately 10-20% Hg0 and 75-85% Hg(II). The partitioning of mercury in flue gas between the elemental and divalent forms may be dependent on the concentration of particulate carbon, HCl and other pollutants in the stack emissions. The emission of mercury from combustion facilities depends on the species in the exhaust stream and the type of air pollution control equipment used at the source. Air pollution control equipment for mercury removal at combustion facilities includes activated carbon injection, sodium sulfide injection and wet lime/limestone flue gas desulfurization. White Hg(II) is water-soluble and may be removed form the atmosphere by wet and dry deposition close to the combustion sources, the combination of a high vapor pressure and low water-solubility facilitate the long-range transport of Hg0 in the atmosphere. Background mercury in the atmosphere is predominantly Hg0. Elemental mercury is eventually removed from the atmosphere by dry deposition onto surfaces and by wet deposition after oxidation to water-soluble, divalent mercury. 62 refs., 2 figs., 1 tab

  15. 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

  16. EVALUATION OF THE POTENTIAL CARCINOGENICITY OF CYCLOPHOSPHAMIDE

    Science.gov (United States)

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

  17. Hepatic metabolism of carcinogenic β-asarone.

    Science.gov (United States)

    Cartus, Alexander T; Stegmüller, Simone; Simson, Nadine; Wahl, Andrea; Neef, Sylvia; Kelm, Harald; Schrenk, Dieter

    2015-09-21

    compounds (E)- and (Z)-3'-oxoasarone (5, 7). 1'-Oxoasarone (3) was probably also formed in incubations with 1 but was not detectable, possibly due to its rapid reaction with nucleophiles. Eventually, three mono-O-demethylated metabolites of 1 were detected in minor concentrations. The time course of metabolite formation and determined kinetic parameters show little species-specific differences in the microsomal metabolism of 1. Furthermore, the kinetic parameters imply a very low dependence of the pattern of metabolite formation from substrate concentration. In human liver microsomes, 71-75% of 1 will be metabolized via epoxidation, 21-15% via hydroxylation (and further oxidation), and 8-10% via demethylation at lower as well as higher concentrations of 1, respectively (relative values). On the basis of our results, we hypothesize that the genotoxic epoxides of 1 are the ultimate carcinogens formed from 1. PMID:26273788

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

    DEFF Research Database (Denmark)

    van der Laan, Jan-Willem; Spindler, Per

    2002-01-01

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

  19. The Weight of Evidence Does Not Support the Listing of Styrene as "Reasonably Anticipated to be a Human Carcinogen" in NTP's Twelfth Report on Carcinogens.

    Science.gov (United States)

    Rhomberg, Lorenz R; Goodman, Julie E; Prueitt, Robyn L

    2013-01-01

    Styrene was listed as "reasonably anticipated to be a human carcinogen" in the twelfth edition of the National Toxicology Program's Report on Carcinogens based on what we contend are erroneous findings of limited evidence of carcinogenicity in humans, sufficient evidence of carcinogenicity in experimental animals, and supporting mechanistic data. The epidemiology studies show no consistent increased incidence of, or mortality from, any type of cancer. In animal studies, increased incidence rates of mostly benign tumors have been observed only in certain strains of one species (mice) and at one tissue site (lung). The lack of concordance of tumor incidence and tumor type among animals (even within the same species) and humans indicates that there has been no particular cancer consistently observed among all available studies. The only plausible mechanism for styrene-induced carcinogenesis-a non-genotoxic mode of action that is specific to the mouse lung-is not relevant to humans. As a whole, the evidence does not support the characterization of styrene as "reasonably anticipated to be a human carcinogen," and styrene should not be listed in the Report on Carcinogens. PMID:23335843

  20. Risk assessment of DNA-reactive carcinogens in food

    International Nuclear Information System (INIS)

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

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

    OpenAIRE

    Contrera, J F; DeGeorge, J J

    1998-01-01

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

  2. Physiological and Genotypic Characteristics of Nitrous Oxide (N2O)-Emitting Pseudomonas Species Isolated from Dent Corn Andisol Farmland in Hokkaido, Japan.

    Science.gov (United States)

    Nie, Yanxia; Li, Li; Isoda, Reika; Wang, Mengcen; Hatano, Ryusuke; Hashidoko, Yasuyuki

    2016-06-25

    Dent corn Andisol at the Hokkaido University Shizunai Livestock Experimental Farm actively emits nitrous oxide (N2O). In order to screen for culturable and active N2O emitters with high N2O emission potential, soft gel medium containing excess KNO3 was inoculated with soil suspensions from farm soil samples collected at different land managements. Dominant bacterial colonies were searched for among 20 of the actively N2O-emitting cultures from post-harvest soil and 19 from pre-tilled soil, and all isolates were subjected to the culture-based N2O emission assay. Ten active N2O-emitting bacteria, four from post-harvest soil and six from pre-tilled soil, out of 156 isolates were identified as genus Pseudomonas by 16S rRNA gene sequencing. These N2O emitters showed clear responses to NO3(-) within a neutral pH range (5.5-6.7), and accelerated N2O production with 1.5-15 mM sucrose supplementation, suggesting the production of N2O during the denitrification process. However, the negative responses of 6 active N2O emitters, 3 from post-harvest soil and 3 from pre-tilled soil, out of the 10 isolates in the acetylene-blocking assay suggest that these 6 N2O emitters are incomplete denitrifiers that have lost their N2O reductase (N2OR) activity. Although the PCR assay for the denitrification-associated genes, narG and nirK/S, was positive in all 10 Pseudomonas isolates, those negative in the acetylene-blocking assay were nosZ-negative. Therefore, these results imply that the high N2O emission potential of dent corn Andisol is partly attributed to saprophytic, nosZ gene-missing pseudomonad denitrifiers. PMID:27109825

  3. Biomonitoring of exposure to chemical carcinogens

    Czech Academy of Sciences Publication Activity Database

    Šrám, Radim

    Poland : Institute of Nuclear Physics, 2002. s. -. [NATO advanced research workshop (Human monitoring for genetic effects). 23.06.2002-27.06.2002, Krakow - Poland] Institutional research plan: CEZ:AV0Z5039906 Keywords : carcinogens Subject RIV: FH - Neurology

  4. Mutagenic and carcinogenic properties of drinking water

    International Nuclear Information System (INIS)

    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

  5. The multitude and diversity of environmental carcinogens

    International Nuclear Information System (INIS)

    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

  6. The ISS Carcinogens Data Bank (BDC)

    International Nuclear Information System (INIS)

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

  7. Carcinogenic potential of various energy sources

    International Nuclear Information System (INIS)

    Evaluation of the health impacts of different sources of energy should include a comparison of the potential carcinogenic effects of the radioactive and chemical substances produced by various sources. In general, these potential health effects are too small to be measured directly and are therefore estimated by extrapolation, on the basis of a linear dose-response model, from measurable effects at high dose levels. Estimates of the carcinogenic potential of various energy sources available in North America are given in this paper. For most if not all of the energy sources for which data are currently available, it would appear that the known biological benefits in terms of life expectancy greatly outweigh all the potential harm due to carcinogenic (and genetic) effects on human beings, when expressed in the same terms, i.e. life expectancy. (author)

  8. One-step green synthetic approach for the preparation of multicolor emitting copper nanoclusters and their applications in chemical species sensing and bioimaging.

    Science.gov (United States)

    Bhamore, Jigna R; Jha, Sanjay; Mungara, Anil Kumar; Singhal, Rakesh Kumar; Sonkeshariya, Dhanshri; Kailasa, Suresh Kumar

    2016-06-15

    One-step green microwave synthetic approach was developed for the synthesis of copper nanoclusters (Cu NCs) and used as a fluorescent probe for the sensitive detection of thiram and paraquat in water and food samples. Unexpectedly, the prepared Cu NCs exhibited strong orange fluorescence and showed emission peak at 600nm, respectively. Under optimized conditions, the quenching of Cu NCs emission peak at 600nm was linearly proportional to thiram and paraquat concentrations in the ranges from 0.5 to 1000µM, and from 0.2 to 1000µM, with detection limits of 70nM and 49nM, respectively. In addition, bioimaging studies against Bacillus subtilis through confocal fluorescence microscopy indicated that Cu NCs showed strong blue and green fluorescence signals, good permeability and minimum toxicity against the various bacteria species, which demonstrates their potential feasibility for chemical species sensing and bioimaging applications. PMID:26851582

  9. Mechanisms of cellular transformation by carcinogenic agents

    International Nuclear Information System (INIS)

    This book contains 14 chapters. Some of the chapter titles are: DNA Modification by Chemical Carcinogens; Role of DNA Lesions and Repair in the Transformation of Human Cells; The Induction and Regulation of Radiogenic Transformation In Vitro: Cellular and Molecular Mechanisms; Cellular Transformation by Adenoviruses; and The fos Gene

  10. Biomonitoring human exposure to environmental carcinogenic chemicals

    DEFF Research Database (Denmark)

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

    1996-01-01

    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...

  11. Mechanisms of cellular transformation by carcinogenic agents

    Energy Technology Data Exchange (ETDEWEB)

    Grunberger, D.; Goff, S.P.

    1987-01-01

    This book contains 14 chapters. Some of the chapter titles are: DNA Modification by Chemical Carcinogens; Role of DNA Lesions and Repair in the Transformation of Human Cells; The Induction and Regulation of Radiogenic Transformation In Vitro: Cellular and Molecular Mechanisms; Cellular Transformation by Adenoviruses; and The fos Gene.

  12. Carcinogenic effects of radiation-introduction

    International Nuclear Information System (INIS)

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

  13. Carcinogens formed when Meat is Cooked

    Energy Technology Data Exchange (ETDEWEB)

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

    2003-05-30

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

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

    International Nuclear Information System (INIS)

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

  15. Multicomponent criteria for predicting carcinogenicity: dataset of 30 NTP chemicals.

    OpenAIRE

    Huff, J; Weisburger, E; Fung, V A

    1996-01-01

    This article is in response to the challenge issued to the scientific community by the National Toxicology Program to predict the carcinogenicity potential of 30 chemicals previously selected for long-term carcinogenicity testing. Utilizing the available toxicologic, genetic, and structural information on 30 chemicals previously selected for long-term carcinogenicity testing, we predict that 16 chemicals (53%) would induce some indication of carcinogenic activity in rodents; we further predic...

  16. EVALUATION OF THE POTENTIAL CARCINOGENICITY OF COKE OVEN EMISSIONS

    Science.gov (United States)

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

  17. EVALUATION OF THE POTENTIAL CARCINOGENICITY OF TRYPAN BLUE

    Science.gov (United States)

    Trypan blue is a probable human carcinogen, classified as weight-of-evidence Group B2 under the EPA Guidelines for Carcinogen Risk Assessment (U.S. EPA, 1986a). vidence on potential carcinogenicity from animal studies is "Sufficient," and the evidence from human studies is "No Da...

  18. Predicting carcinogenicity of organic compounds based on CPDB.

    Science.gov (United States)

    Wu, Xiuchao; Zhang, Qingzhu; Wang, Hui; Hu, Jingtian

    2015-11-01

    Cancer is a major killer of human health and predictions for the carcinogenicity of chemicals are of great importance. In this article, predictive models for the carcinogenicity of organic compounds using QSAR methods for rats and mice were developed based on the data from CPDB. The models was developed based on the data of specific target site liver and classified according to sex of rats and mice. Meanwhile, models were also classified according to whether there is a ring in the molecular structure in order to reduce the diversity of molecular structure. Therefore, eight local models were developed in the final. Taking into account the complexity of carcinogenesis and in order to obtain as much information, DRAGON descriptors were selected as the variables used to develop models. Fitting ability, robustness and predictive power of the models were assessed according to the OECD principles. The external predictive coefficients for validation sets of each model were in the range of 0.711-0.906, and for the whole data in each model were all greater than 0.8, which represents that all models have good predictivity. In order to study the mechanism of carcinogenesis, standardized regression coefficients were calculated for all predictor variables. In addition, the effect of animal sex on carcinogenesis was compared and a trend that female showed stronger tolerance for cancerogen than male in both species was appeared. PMID:26070146

  19. Review of genotoxicity and rat carcinogenicity investigations with astaxanthin.

    Science.gov (United States)

    Edwards, James A; Bellion, Phillip; Beilstein, Paul; Rümbeli, Robert; Schierle, Joseph

    2016-03-01

    Synthetic astaxanthin has been extensively tested for safety. Genotoxicity studies including Ames and in vitro Micronucleus Tests show absence of genotoxic potential. Although a long-term mouse study showed no carcinogenicity potential, the rat carcinogenicity study with dietary dosages of 0 (control), 0 (placebo beadlet), 40, 200 and 1000 mg astaxanthin/kg bw/day showed an increased incidence of benign, hepatocellular adenoma in females only, at 200 mg/kg bw/day and above. There was no clear evidence of toxicity during the in-life phase. Discoloration of feces was observed and a reduction in body weight gain in all groups receiving beadlets, probably reflecting a nutritional influence. Blood sampling confirmed systemic exposure and some minor clinical chemistry differences in females at 200 and 1000 mg/kg bw/day. There was no effect on adjusted liver weight. Histopathological examination showed hepatic changes indicative of slight hepatotoxicity and hepatocyte regeneration in females at 200 and 1000 mg/kg bw/day, in addition to the adenoma. Taking into account this pathological background in the female rat, and a wide variety of other supporting information, it is concluded that the hepatocellular adenoma in female rats was secondary to hepatotoxicity and regeneration, and is most probably a species-specific phenomenon of doubtful human relevance. PMID:26713891

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

    Science.gov (United States)

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

    2014-07-01

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

  1. Current and emerging challenges in toxicopathology: Carcinogenic threshold of phenobarbital and proof of arsenic carcinogenicity using rat medium-term bioassays for carcinogens

    International Nuclear Information System (INIS)

    For the last 25 years, Prof. Nobuyuki Ito and his laboratory have focused on the development of liver medium-term bioassay system for detection of carcinogens in F344 rats utilizing glutathione S-transferase placental form (GST-P)-positive foci as an end point marker. In this presentation, the outline and samples of medium-term bioassay systems were described. Furthermore, our data demonstrated the presence of a threshold for the non-genotoxic carcinogen, phenobarbital (PB), and the lack of linearity in the low-dose area of the dose-response curve, providing evidence for hormesis. In addition, the establishment and applications of multiorgan carcinogenicity bioassay (DMBDD model), used for the examination of the carcinogenicity of genotoxic and non-genotoxic chemicals, are discussed. Dimethylarsinic acid, one of organic arsenics, was found to be carcinogenic in rat bladder using DMBDD model and carcinogenicity test

  2. The multitude and diversity of environmental carcinogens.

    OpenAIRE

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

    2007-01-01

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

  3. 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.

  4. Carcinogenic risk of hot-particle exposures

    International Nuclear Information System (INIS)

    It has been suggested that spatially non-uniform radiation exposures, such as those from small radioactive particles ('hot particles'), may be very much more carcinogenic than when the same amount of energy is deposited uniformly throughout a tissue volume. This review provides a brief summary of in vivo and in vitro experimental findings, and human epidemiology data, which can be used to evaluate the veracity of this suggestion. Overall, this supports the contrary view and indicates that average dose, as advocated by the ICRP, is likely to provide a reasonable estimate of carcinogenic risk (within a factor of ∼ ±3). There are few human data with which to address this issue. The limited data on lung cancer mortality following occupational inhalation of plutonium aerosols, and the incidence of liver cancer and leukaemia due to thorotrast administration for clinical diagnosis, do not appear to support a significant enhancement factor. Very few animal studies, including mainly lung and skin exposures, provide any indication of a hot-particle enhancement for carcinogenicity. Some recent in vitro malignant transformation experiments provide evidence for an enhanced cell transformation for hot-particle exposures but, properly interpreted, the effect is modest. Few studies extend below absorbed doses of ∼ 0.1 Gy. (review)

  5. 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. PMID:21170807

  6. Impact and compliance: OSHA Carcinogen Policy

    Energy Technology Data Exchange (ETDEWEB)

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

    1980-06-26

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

  7. Carcinogenic potential of hydrotreated petroleum aromatic extracts.

    Science.gov (United States)

    Doak, S M; Hend, R W; van der Wiel, A; Hunt, P F

    1985-06-01

    Five experimental petroleum extracts were produced from luboil distillates derived from Middle East paraffinic crude by solvent extraction and severe hydrotreatment. The polycyclic aromatic content (PCA) of the extracts was determined by dimethyl sulphoxide extraction and ranged from 3.7-9.2% w/w. The five extracts were evaluated for their potential to induce cutaneous and systemic neoplasia in female mice derived from Carworth Farm No 1 strain (CF1). The test substances were applied undiluted (0.2 ml per application) to the shorn dorsal skin twice weekly for up to 78 weeks, with 48 mice in each treatment group and 96 in the untreated control group; two further groups, each of 48 mice, were similarly treated either with a non-hydrotreated commercial aromatic extract (PCA content, 19.7% w/v) or with a low dose of benzo(a)pyrene (12.5 micrograms/ml acetone). The mice were housed individually in polypropylene cages in specified pathogen free conditions. The incidence of cutaneous and systemic tumours was determined from histological analysis of haematoxylin and eosin stained tissue sections. The results were correlated with the PCA content of the extracts and compared with those from female mice exposed to a non-hydrotreated commercial aromatic extract. Four of the hydrotreated extracts were carcinogenic for murine skin; the two products with the lower PCA contents were less carcinogenic than the products with the higher PCA contents and all were less carcinogenic than the commercial extract. One extract with the lowest PCA content was non-carcinogenic. Thus refining by severe hydrotreatment was an effective method of reducing the carcinogenic potential of petroleum aromatic extracts. Although other physicochemical properties may influence the biological activity of oil products, the PCA content determined by dimethyl sulphoxide extraction may be a useful indicator of the potential of oil products to induce cutaneous tumours in experimental animals. There was no

  8. Molecular basis of carcinogenicity of tungsten alloy particles

    International Nuclear Information System (INIS)

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

  9. 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

  10. Radiation emitting devices act

    International Nuclear Information System (INIS)

    This Act, entitled the Radiation Emitting Devices Act, is concerned with the sale and importation of radiation emitting devices. Laws relating to the sale, lease or import, labelling, advertising, packaging, safety standards and inspection of these devices are listed as well as penalties for any person who is convicted of breaking these laws

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

    International Nuclear Information System (INIS)

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

  12. Carcinogen-induced damage to DNA

    International Nuclear Information System (INIS)

    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 3H-anti-BPDE, can replicate their DNA at low doses of carcinogen. Unexcised 3H 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

  13. RADON AND CARCINOGENIC RISK IN MOSCOW

    OpenAIRE

    S. M. Golovanev

    2015-01-01

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

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

    International Nuclear Information System (INIS)

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

  15. Trace elements and carcinogenicity: a subject in review

    OpenAIRE

    Mulware, Stephen Juma

    2012-01-01

    Cancer is known to be a multi-step process, which involves different stages including initiation, promotion, progression and metastasis. Chemical carcinogens including most trace elements can change any of these processes to induce their carcinogenic effects. Various studies confirm that cancer arises from the accumulation of irreversible DNA damage, which results from multiple mutations in critical genes in the body organ. Chemical carcinogens most often directly or after xenobiotic metaboli...

  16. A review of mechanisms of acrylamide carcinogenicity.

    Science.gov (United States)

    Besaratinia, Ahmad; Pfeifer, Gerd P

    2007-03-01

    The fact that acrylamide, a proven rodent carcinogen, is present in significant quantities (up to several mg/kg of foodstuff) in a wide range of commonly consumed human foods is alarming. Attempts to determine a possible involvement of dietary acrylamide in human cancers have not been conclusive, however. To resolve the carcinogenicity of acrylamide to humans, the as yet unknown mechanism of action of acrylamide needs to be unraveled. The present review is a synopsis of research on the known and hypothetical modes of action of acrylamide of relevance for carcinogenesis. Both genotoxic and non-genotoxic modes of action of acrylamide are discussed with special emphasis on DNA adduct-targeted mutagenesis. Mechanistic data are presented from various experimental systems including in vitro experiments and in vivo rodent and human studies with special focus on mouse models. Human exposure data, including estimates of daily intake of dietary acrylamide in different populations and the corresponding cancer risk assessments are provided. The significant gaps in knowledge, which currently preclude a more definitive evaluation of human cancer risk due to exposure to dietary acrylamide, are highlighted. Future directions for research on acrylamide and cancer are outlined, and potential challenges are underscored. PMID:17234719

  17. Estimation of carcinogenicity using molecular fragments tree.

    Science.gov (United States)

    Wang, Yong; Lu, Jing; Wang, Fei; Shen, Qiancheng; Zheng, Mingyue; Luo, Xiaomin; Zhu, Weiliang; Jiang, Hualiang; Chen, Kaixian

    2012-08-27

    Carcinogenicity is an important toxicological endpoint that poses high concern to drug discovery. In this study, we developed a method to extract structural alerts (SAs) and modulating factors of carcinogens on the basis of statistical analyses. First, the Gaston algorithm, a frequent subgraph mining method, was used to detect substructures that occurred at least six times. Then, a molecular fragments tree was built and pruned to select high-quality SAs. The p-value of the parent node in the tree and that of its children nodes were compared, and the nodes that had a higher statistical significance in binomial tests were retained. Finally, modulating factors that suppressed the toxic effects of SAs were extracted by three self-defining rules. The accuracy of the 77 SAs plus four SA/modulating factor pairs model for the training set, and the test set was 0.70 and 0.65, respectively. Our model has higher predictive ability than Benigni's model, especially in the test set. The results highlight that this method is preferable in terms of prediction accuracy, and the selected SAs are useful for prediction as well as interpretation. Moreover, our method is convenient to users in that it can extract SAs from a database using an automated and unbiased manner that does not rely on a priori knowledge of mechanism of action. PMID:22834690

  18. 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.

  19. The role of biomethylation in toxicity and carcinogenicity of arsenic: a research update.

    OpenAIRE

    Stýblo, Miroslav; Drobná, Zuzana; Jaspers, Ilona; Lin, Shan; Thomas, David J.

    2002-01-01

    Recent research of the metabolism and biological effects of arsenic has profoundly changed our understanding of the role of metabolism in modulation of toxicity and carcinogenicity of this metalloid. Historically, the enzymatic conversion of inorganic arsenic to mono- and dimethylated species has been considered a major mechanism for detoxification of inorganic arsenic. However, compelling experimental evidence obtained from several laboratories suggests that biomethylation, particularly the ...

  20. Zizyphus Spina-Christi Extract Protects Against Aflatoxin B1-Intitiated Hepatic Carcinogenicity

    OpenAIRE

    Abdel-Wahhab, Mosaad A; Omara, Enayat A.; Abdel-Galil, Mona M; Hassan, Nabila S.; Nada, Somaia A; Saeed, Ataa; ElSayed, Magdy M

    2007-01-01

    Aflatoxins (AF), a group of closely related, extremely toxic mycotoxins, produced by Aspergillus flavus and A. parasiticus can occur as natural contaminants of foods and feeds. Aflatoxins have been shown to be hepatotoxic, carcinogenic, mutagenic, and teratogenic to different animal species. Zizyphus spina-christi L. extract was investigated for its antifungal and antimicrobial activities. The aim of the present work was to evaluate the antioxidant activity of the methanol extract of Z. spina...

  1. Light-emitting Diodes

    Science.gov (United States)

    Opel, Daniel R.; Hagstrom, Erika; Pace, Aaron K.; Sisto, Krisanne; Hirano-Ali, Stefanie A.; Desai, Shraddha

    2015-01-01

    Background: In the early 1990s, the biological significance of light-emitting diodes was realized. Since this discovery, various light sources have been investigated for their cutaneous effects. Study design: A Medline search was performed on light-emitting diode lights and their therapeutic effects between 1996 and 2010. Additionally, an open-label, investigator-blinded study was performed using a yellow light-emitting diode device to treat acne, rosacea, photoaging, alopecia areata, and androgenetic alopecia. Results: The authors identified several case-based reports, small case series, and a few randomized controlled trials evaluating the use of four different wavelengths of light-emitting diodes. These devices were classified as red, blue, yellow, or infrared, and covered a wide range of clinical applications. The 21 patients the authors treated had mixed results regarding patient satisfaction and pre- and post-treatment evaluation of improvement in clinical appearance. Conclusion: Review of the literature revealed that differing wavelengths of light-emitting diode devices have many beneficial effects, including wound healing, acne treatment, sunburn prevention, phototherapy for facial rhytides, and skin rejuvenation. The authors’ clinical experience with a specific yellow light-emitting diode device was mixed, depending on the condition being treated, and was likely influenced by the device parameters. PMID:26155326

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

    International Nuclear Information System (INIS)

    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

  3. 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.

  4. Is nitrous oxide a genotoxic carcinogen?

    Science.gov (United States)

    O'Donovan, Michael R; Hammond, Timothy G

    2015-07-01

    Nitrous oxide (N2O) has been widely used as a dental and surgical anaesthetic for over 150 years. However, results from a recent study suggested that increased DNA damage was seen in lymphocytes from surgical patients and this led to its continued clinical use to be questioned. The data can be challenged on technical grounds and must be considered with other studies in order to assess any possible risk. There are other studies indicating that N2O has weak genotoxicity in man, but these are confused by exposure of the populations to other anaesthetic gases including isoflurane and sevoflurane, both of which have also been reported to increase DNA damage. It should be noted that the suggested genotoxic mechanisms are all indirect, including folate deficiency, oxidative stress and homocysteine toxicity. Further, results from in vitro studies indicate that N2O has no direct DNA reactivity as negative results were obtained in a bacterial mutation (Ames) test and an assay for mutation at the hprt locus in Chinese hamster lung cells. Although not performed to definitive study designs, no evidence of carcinogenicity was seen in two long-term tests in mice and another in rats. Although there is some evidence that N2O is weakly genotoxic in humans, this appears to be similar to that reported for isoflurane and sevoflurane and all the postulated mechanisms have clear thresholds with no evidence of direct DNA reactivity. Because any potential genotoxic mechanism would have a threshold, it seems reasonable to conclude that neither occasional high exposure to patients as an anaesthetic nor low-level exposure to staff within published recommended exposure limits presents any significant carcinogenic risk. PMID:25852088

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

    OpenAIRE

    Atherley, Gordon; Whiting, Robert

    1982-01-01

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

  6. 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)

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

    International Nuclear Information System (INIS)

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

  8. 29 CFR 1926.1103 - 13 carcinogens (4-Nitrobiphenyl, etc.).

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false 13 carcinogens (4-Nitrobiphenyl, etc.). 1926.1103 Section 1926.1103 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION... § 1926.1103 13 carcinogens (4-Nitrobiphenyl, etc.). Note: The requirements applicable to...

  9. 29 CFR 1915.1003 - 13 carcinogens (4-Nitrobiphenyl, etc.).

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false 13 carcinogens (4-Nitrobiphenyl, etc.). 1915.1003 Section 1915.1003 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION... Hazardous Substances § 1915.1003 13 carcinogens (4-Nitrobiphenyl, etc.). Note: The requirements...

  10. 29 CFR 1910.1003 - 13 Carcinogens (4-Nitrobiphenyl, etc.).

    Science.gov (United States)

    2010-07-01

    ... employees, designated representatives, and the Assistant Secretary in accordance with 29 CFR 1910.1020 (a... 29 Labor 6 2010-07-01 2010-07-01 false 13 Carcinogens (4-Nitrobiphenyl, etc.). 1910.1003 Section... Substances § 1910.1003 13 Carcinogens (4-Nitrobiphenyl, etc.). (a) Scope and application. (1) This...

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

    OpenAIRE

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

    2009-01-01

    Alachlor and butachlor are chloracetanilide herbicides that induce olfactory tumors in rats, whereas propachlor does not. The mechanism by which alachlor induces tumors is distinct from many other nasal carcinogens, in that alachlor induces a gradual de-differentiation of the olfactory mucosa (OM) to a more respiratory-like epithelium, in contrast to other agents that induce cytotoxicity, followed by an aberrant regenerative response. We studied biochemical and genomic effects of these compou...

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

    OpenAIRE

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

    1981-01-01

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

  13. Radiation emitting devices regulations

    International Nuclear Information System (INIS)

    The Radiation Emitting Devices Regulations are the regulations referred to in the Radiation Emitting Devices Act and relate to the operation of devices. They include standards of design and construction, standards of functioning, warning symbol specifications in addition to information relating to the seizure and detention of machines failing to comply with the regulations. The radiation emitting devices consist of the following: television receivers, extra-oral dental x-ray equipment, microwave ovens, baggage inspection x-ray devices, demonstration--type gas discharge devices, photofluorographic x-ray equipment, laser scanners, demonstration lasers, low energy electron microscopes, high intensity mercury vapour discharge lamps, sunlamps, diagnostic x-ray equipment, ultrasound therapy devices, x-ray diffraction equipment, cabinet x-ray equipment and therapeutic x-ray equipment

  14. Light emitting ceramic device

    Science.gov (United States)

    Valentine, Paul; Edwards, Doreen D.; Walker, Jr., William John; Slack, Lyle H.; Brown, Wayne Douglas; Osborne, Cathy; Norton, Michael; Begley, Richard

    2010-05-18

    A light-emitting ceramic based panel, hereafter termed "electroceramescent" panel, is herein claimed. The electroceramescent panel is formed on a substrate providing mechanical support as well as serving as the base electrode for the device. One or more semiconductive ceramic layers directly overlay the substrate, and electrical conductivity and ionic diffusion are controlled. Light emitting regions overlay the semiconductive ceramic layers, and said regions consist sequentially of a layer of a ceramic insulation layer and an electroluminescent layer, comprised of doped phosphors or the equivalent. One or more conductive top electrode layers having optically transmissive areas overlay the light emitting regions, and a multi-layered top barrier cover comprising one or more optically transmissive non-combustible insulation layers overlay said top electrode regions.

  15. Metabolic dephenylation of the rubber antioxidant N-phenyl-2-naphthylamine to carcinogenic 2-naphthylamine in rats.

    Science.gov (United States)

    Weiss, Tobias; Bolt, Hermann M; Schlüter, Gerhard; Koslitz, Stephan; Taeger, Dirk; Welge, Peter; Brüning, Thomas

    2013-07-01

    N-Phenyl-2-naphthylamine (P2NA) was widely used as oxidation inhibitor, particularly in rubber manufacturing. Technical-grade P2NA was contaminated with carcinogenic 2-naphthylamine (2NA), and bladder cancer risk in exposed workers was attributed to this impurity. Investigations in humans and mammalian species revealed that small amounts of 2NA are excreted into urine after exposure to P2NA. However, since 2NA per se is not carcinogenic and main downstream metabolites of 2NA have not been found in urine so far, it remained uncertain if 2NA derived from P2NA dephenylation is further activated to carcinogenic downstream metabolites. An experimental animal study was therefore designed to indicate if, and if yes to which extent, 2NA from P2NA dephenylation is accessible to the metabolic pathway that is held responsible for the carcinogenicity of 2NA. Groups of 5 male and female CD rats were dosed with P2NA (2-550 mg/kg b.w.) and 2NA (0.075-75 mg/kg b.w.); 2NA-haemoglobin adducts and urinary 2NA excretion were determined applying GC-MS/MS. 2NA haemoglobin adducts originated dose-dependently after 2NA and P2NA dosing. To induce identical adduct concentrations, an approximately 100-200-fold higher dose of P2NA was necessary compared to 2NA. Since haemoglobin adducts are formed by the same pathway (N-hydroxylation) as the ultimate carcinogens from 2NA, the comparison of adduct concentrations after 2NA and P2NA dosage permits a quantitative estimate of the carcinogenicity of P2NA. The results show that 2NA derived from dephenylation of P2NA enters the carcinogenic downstream pathway of 2NA in rats. Hence, the bladder cancer risk after human exposures to P2NA must be re-evaluated. PMID:23423714

  16. Carcinogenicity of trace elements with reference to evaluations made by the International Agency for Research on Cancer.

    Science.gov (United States)

    Boffetta, P

    1993-01-01

    The monograph program of the International Agency for Research of on Cancer has evaluated many trace elements for their carcinogenicity to humans. Five groups of compounds were considered human carcinogens: arsenic and arsenic compounds, beryllium and beryllium compounds, cadmium and cadmium compounds, hexavalent chromium compounds, and nickel compounds. Antimony trioxide, cobalt and cobalt compounds, lead and inorganic lead compounds, methylmercury compounds, and metallic nickel were considered possibly carcinogenic to humans. Antimony trisulfide, trivalent chromium compounds, metallic chromium, ferric oxide, organolead compounds, metallic mercury, inorganic mercury compounds, selenium and selenium compounds, and titanium dioxide were not classifiable. Trace elements studied to a limited extent include copper, manganese, tin, vanadium, and zinc. Among the problems are the lack of relevant data, the definition of active species, the extrapolation of the results of experimental studies to humans, the methodological problems of epidemiologic studies, and the possible anticarcinogenic activity of some trace elements. PMID:8159977

  17. Light-Emitting Pickles

    Science.gov (United States)

    Vollmer, M.; Mollmann, K-P.

    2015-01-01

    We present experiments giving new insights into the classical light-emitting pickle experiment. In particular, measurements of the spectra and temperatures, as well as high-speed recordings, reveal that light emission is connected to the polarity of the electrodes and the presence of hydrogen.

  18. 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). PMID:25659303

  19. Comparison of in vivo genotoxic and carcinogenic potency to augment mode of action analysis: Case study with hexavalent chromium.

    Science.gov (United States)

    Thompson, Chad M; Bichteler, Anne; Rager, Julia E; Suh, Mina; Proctor, Deborah M; Haws, Laurie C; Harris, Mark A

    2016-04-01

    Recent analyses-highlighted by the International Workshops on Genotoxicity Testing Working Group on Quantitative Approaches to Genetic Toxicology Risk Assessment-have identified a correlation between (log) estimates of a carcinogen's in vivo genotoxic potency and in vivo carcinogenic potency in typical laboratory animal models, even when the underlying data have not been matched for tissue, species, or strain. Such a correlation could have important implications for risk assessment, including informing the mode of action (MOA) of specific carcinogens. When in vivo genotoxic potency is weak relative to carcinogenic potency, MOAs other than genotoxicity (e.g., endocrine disruption or regenerative hyperplasia) may be operational. Herein, we review recent in vivo genotoxicity and carcinogenicity data for hexavalent chromium (Cr(VI)), following oral ingestion, in relevant tissues and species in the context of the aforementioned correlation. Potency estimates were generated using benchmark doses, or no-observable-adverse-effect-levels when data were not amenable to dose-response modeling. While the ratio between log values for carcinogenic and genotoxic potency was ≥1 for many compounds, the ratios for several Cr(VI) datasets (including in target tissue) were less than unity. In fact, the ratios for Cr(VI) clustered closely with ratios for chloroform and diethanolamine, two chemicals posited to have non-genotoxic MOAs. These findings suggest that genotoxicity may not play a major role in the cancers observed in rodents following exposure to high concentrations of Cr(VI) in drinking water-a finding consistent with recent MOA and adverse outcome pathway (AOP) analyses concerning Cr(VI). This semi-quantitative analysis, therefore, may be useful to augment traditional MOA and AOP analyses. More case examples will be needed to further explore the general applicability and validity of this approach for human health risk assessment. PMID:27085472

  20. Identification and monitoring of non-radiological carcinogens

    International Nuclear Information System (INIS)

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

  1. Biologic markers in risk assessment for environmental carcinogens

    Energy Technology Data Exchange (ETDEWEB)

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

    1991-01-01

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

  2. Biologic markers in risk assessment for environmental carcinogens

    International Nuclear Information System (INIS)

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

  3. 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

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

    OpenAIRE

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

    2013-01-01

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

  5. Biologic markers in risk assessment for environmental carcinogens

    OpenAIRE

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

    1991-01-01

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

  6. Carcinogenicity evaluations and ongoing studies: the IARC databases.

    OpenAIRE

    Vainio, H.; Coleman, M.; Wilbourn, J

    1991-01-01

    Many thousands of chemicals are produced industrially and many more occur naturally. Information on the toxicology of these chemicals is often minimal or absent. The International Agency for Research on Cancer (IARC) has published evaluations of the carcinogenic risk to humans of over 700 chemicals, groups of chemicals, and complex mixtures as a regular series of monographs. A database has been created containing summaries of all the relevant epidemiological, animal carcinogenicity, and other...

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

    Science.gov (United States)

    Iwata, K; Inui, N; Takeuchi, T

    1981-01-01

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

  8. 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

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    2014-07-30

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

  11. 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.

  12. Food Additives of Public Concern for their Carcinogenicity

    Directory of Open Access Journals (Sweden)

    Fatih Gultekin

    2015-08-01

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

  13. Understanding arsenic carcinogenicity by the use of animal models

    International Nuclear Information System (INIS)

    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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  16. 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

  17. Light Emitting Diodes (LEDs)

    Science.gov (United States)

    1997-01-01

    A special lighting technology was developed for space-based commercial plant growth research on NASA's Space Shuttle. Surgeons have used this technology to treat brain cancer on Earth, in two successful operations. The treatment technique, called Photodynamic Therapy, requires the surgeon to use tiny, pinhead-size Light Emitting Diodes (LEDs) (a source that releases long wavelengths of light ) to activate light-sensitive, tumor-treating drugs. 'A young woman operated on in May 1999 has fully recovered with no complications and no evidence of the tumor coming back,' said Dr. Harry Whelan, a pediatric neurologist at the Medical Hospital of Wisconsin in Milwaukee. Laser light has been used for this type of surgery in the past, but the LED light illuminates through all nearby tissues, reaching parts of a tumor that shorter wavelengths of laser light carnot. The new probe is safer because the longer wavelengths of light are cooler than the shorter wavelengths of laser light, making the LED less likely to injure normal brain tissue near the tumor. It can be used for hours at a time while still remaining cool to the touch. The LED light source is compact, about the size of a briefcase, and can be purchased for a fraction of the cost of a laser. The LEDs, developed and managed by NASA's Marshall Space Flight Center, have been used on seven Space Shuttle flights inside the Microgravity Astroculture Facility. This technology has also been successfully used to further commercial research in crop growth.

  18. Light Emitting Diode (LED)

    Science.gov (United States)

    1997-01-01

    A special lighting technology was developed for space-based commercial plant growth research on NASA's Space Shuttle. Surgeons have used this technology to treat brain cancer on Earth, in two successful operations. The treatment technique called photodynamic therapy, requires the surgeon to use tiny pinhead-size Light Emitting Diodes (LEDs) (a source releasing long wavelengths of light) to activate light-sensitive, tumor-treating drugs. Laser light has been used for this type of surgery in the past, but the LED light illuminates through all nearby tissues, reaching parts of a tumor that shorter wavelengths of laser light carnot. The new probe is safer because the longer wavelengths of light are cooler than the shorter wavelengths of laser light, making the LED less likely to injure normal brain tissue near the tumor. It can also be used for hours at a time while still remaining cool to the touch. The LED probe consists of 144 tiny pinhead-size diodes, is 9-inches long, and about one-half-inch in diameter. The small balloon aids in even distribution of the light source. The LED light source is compact, about the size of a briefcase, and can be purchased for a fraction of the cost of a laser. The probe was developed for photodynamic cancer therapy by the Marshall Space Flight Center under a NASA Small Business Innovative Research program grant.

  19. Polymer light emitting diodes

    International Nuclear Information System (INIS)

    We study sandwich type semiconducting polymer light emitting diodes; anode/polymer/cathode. ITO is selected as anode, this polymer is a blend of a commercially available polymer with a high hole transport ability: polyvinyl-carbazole and a laser dye: coumarin-515. Magnesium covered with silver is chosen for the anode. We study the influence of polymer thickness and coumarin doping ratio on electroluminescence spectrum, electric characteristics and quantum efficiency. An important drawback is that diodes lifetime remains low. In the second part of our study we determine degradations causes with X-Ray reflectivity experiments. It may be due to ITO very high roughness. We realize a new type of planar electroluminescent device: a channel type electroluminescent device in which polymer layer is inserted into an aluminium channel. Such a device is by far more stable than using classical sandwich structures with the same polymer composition: indeed, charges are generated by internal-field ionization and there is no injection from the electrode to the polymer. This avoids electrochemical reactions at electrodes, thus reducing degradations routes. (author)

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

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

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

  1. Chronic toxicity and carcinogenicity study of erythritol in rats

    NARCIS (Netherlands)

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

    1996-01-01

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

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

    NARCIS (Netherlands)

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

    2015-01-01

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

  3. Modern Electrochemical Methods for Monitoring of Chemical Carcinogens

    OpenAIRE

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

    2005-01-01

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

  4. DETECTION OF CARCINOGENICITY BASED ON MUTAGENICITY IN ARABIDOPSIS

    Science.gov (United States)

    Thirty-seven synthetic chemicals plus two mycotoxins were tested for mutagenicity in an Arabidopsis embryo system. The results of this test, prokaryotic repair tests, bacterial mutation assays, eukaryotic cell systems, and in vivo tests were compared to the carcinogenicity classi...

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

    Institute of Scientific and Technical Information of China (English)

    J.A.CASTRO; M.I.DiazGomez; 等

    1993-01-01

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

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

    NARCIS (Netherlands)

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

    2005-01-01

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

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

    NARCIS (Netherlands)

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

    2014-01-01

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

  8. COMPLEMENTARITY OF GENOTOXIC AND NONGENOTOXIC PREDICTORS OF RODENT CARCINOGENICITY

    Science.gov (United States)

    Twenty-one chemicals known to be carcinogenic in rodent bioassays were selected for study. he chemicals were administered by gavage in two dose levels to female Sprague-Dawley rats. he effects of these 21 chemicals on four biochemical assays (hepatic DNA damage by alkaline elutio...

  9. Positron emitting pharmaceuticals

    International Nuclear Information System (INIS)

    Positron Emission Tomography (PET) imaging of physiology at the molecular level bridges the gap between laboratory science and clinical medicine by providing the most specific and sensitive means for imaging molecular pathways and interactions in tissues of man. PET-imaging requires the use Positron Emitting Radiopharmaceuticals (PRPs), which are radioactively labeled 'true metabolites' i.e., sugars, amino acids, fatty acids etc., essentially made of H, C, N and O which the cells in the body can metabolize. The PET-isotopes: 11C, 15O, 13N and 18F (instead of H) are cyclotron produced and are short-lived, which places several constraints on the synthesis time for the PRPs, quality control and their clinical use as compared to the conventional 99mTc- and other SPECT-RPs widely used in nuclear medicine. There are large number of published reports showing the utility of several PRPs labeled with 18F (T1/2 = 110 min) and 11C (T1/2 = 20 min). A few PRPs have been labeled with 13N (T1/2 = 10 min). 15O (T1/2 = 2min) is used mostly as H215O, C15 or C15O2. 18F-radiopharmaceuticals can be made at a medical cyclotron facility and sent to PET -imaging centres, which can be reached in a couple of hours. The sensitivity of PET -imaging has encouraged R and D in several other PRPs, labeled with viz., 68Ga (generator produced, T1/2 68 min), 124I (cyclotron, T1/2 4.2 d), 82Rb (generator, T1/2 75s), 64Cu (cyclotron, T1/2 12h), and 94mTc (cyclotron, T1/2 52 min). Due to its relevance in several diseases, particularly cancer, PET-imaging has made major scientific contribution to drug development, particularly for neurological diseases and cancer treatment. (author)

  10. Carcinogenicity of the insulation wools: reassessment of the IARC evaluation.

    Science.gov (United States)

    Brown, R C; Davis, J M; Douglas, D; Gruber, U F; Hoskins, J A; Ilgren, E B; Johnson, N F; Rossiter, C E; Wagner, J C

    1991-08-01

    In assessing the health evidence concerning man-made mineral fibers, the chemical composition, surface activity, durability, and size of fibers have to be taken into account. Special-purpose fine glass fibers need to be separated from the insulation wools (glass, rock, and slag wool). The epidemiological evidence is sufficient to conclude that there has been no mesothelioma risk to workers producing or using glass wool, rock wool, or slag wool. The epidemiological studies have been large and powerful, and they show no evidence of a cause-effect relationship between lung cancer and exposure to glass wool, rock wool, or slag wool fibers. There is some evidence of a small cancer hazard attached to the manufacturing process in slag wool plants 20 to 50 years ago, when asbestos was used in some products and other carcinogenic substances were present. However, this hazard is not associated with any index of exposure to slag wool itself. Animal inhalation studies of ordinary insulation wools also show that there is no evidence of hazard associated with exposure to these relatively coarse, soluble fibers. The evidence of carcinogenicity is limited to experiments with special-purpose fine durable glass fibers or experimental fibers, and only when these fibers are injected directly into the pleural or peritoneal cavity. Multiple chronic inhalation studies of these same special-purpose fine glass fibers have not produced evidence of carcinogenicity. It is suggested that the present IARC evaluation of the carcinogenic risk of insulation wools should be revised to Category 3: not classifiable as to carcinogenicity to humans. PMID:1947241

  11. Biostatistical issues in the design and analysis of animal carcinogenicity experiments.

    OpenAIRE

    Portier, C.J.

    1994-01-01

    Two-year animal carcinogenicity experiments are used to evaluate the potential carcinogenicity from exposure to chemicals. The choice of exposure levels, the allocation of animals to doses, the length of exposure, and the choice of interim sacrifice times all affect the power of statistical tests for carcinogenic effects and the variance of interpolated estimates of carcinogenic risk. In this paper, one aspect of this problems is considered: the ability of tumor incidence data to provide info...

  12. Multiple mechanisms for the carcinogenic effects of asbestos and other mineral fibers.

    OpenAIRE

    Barrett, J C; Lamb, P W; Wiseman, R. W.

    1989-01-01

    Asbestos and other mineral fibers are carcinogenic to humans and animals but differ from many carcinogens in that they do not induce gene mutations. An understanding of these interesting human carcinogens, therefore, is an important problem in cancer research. Asbestos and other fibers induce predominantly two types of cancers: mesotheliomas and bronchogenic carcinomas. Fiber size is an important factor in the carcinogenic activity of these substances as has been shown for mesothelioma induct...

  13. In vivo Comet assay on isolated kidney cells to distinguish genotoxic carcinogens from epigenetic carcinogens or cytotoxic compounds.

    Science.gov (United States)

    Nesslany, Fabrice; Zennouche, Nadia; Simar-Meintières, Sophie; Talahari, Ismaïl; Nkili-Mboui, Esther-Nadège; Marzin, Daniel

    2007-06-15

    The objective of this study was to determine the ability of the alkaline in vivo Comet assay (pH>13) to distinguish genotoxic carcinogens from epigenetic carcinogens when performed on freshly isolated kidney cells and to determine the possible interference of cytotoxicity by assessing DNA damage induced by renal genotoxic, epigenetic or toxic compounds after enzymatic isolation of kidney cells from OFA Sprague-Dawley male rats. The ability of the Comet assay to distinguish (1) genotoxicity versus cytotoxicity and (2) genotoxic versus non-genotoxic (epigenetic) carcinogens, was thus investigated by studying five known genotoxic renal carcinogens acting through diverse mechanisms of action, i.e. streptozotocin, aristolochic acids, 2-nitroanisole, potassium bromate and cisplatin, two rodent renal epigenetic carcinogens: d-limonene and ciclosporine and two nephrotoxic compounds: streptomycin and indomethacin. Animals were treated once with the test compound by the appropriate route of administration and genotoxic effects were measured at the two sampling times of 3-6 and 22-26h after treatment. Regarding the tissue processing, the limited background level of DNA migration observed in the negative control groups throughout all experiments demonstrated that the enzymatic isolation method implemented in the current study is appropriate. On the other hand, streptozotocin, 20mg/kg, used as positive reference control concurrently to each assay, caused a clear increase in the mean Olive Tail Moment median value, which allows validating the current methodology. Under these experimental conditions, the in vivo rodent Comet assay demonstrated good sensitivity and good specificity: all the five renal genotoxic carcinogens were clearly detected in at least one expression period either directly or indirectly, as in the case of cisplatin: for this cross-linking agent, the significant decrease in DNA migration observed under standard electrophoresis conditions was clearly amplified

  14. Plasma proteins as early biomarkers of exposure to carcinogenic aromatic amines.

    Science.gov (United States)

    Miller, M J; Parmelee, D C; Benjamin, T; Sechi, S; Dooley, K L; Kadlubar, F F

    1994-12-01

    Two-dimensional gel electrophoresis (2DG) has been used to study the changes induced in dog plasma polypeptides by the known urinary bladder carcinogens, 4-aminobiphenyl (4-ABP) and 2-naphthylamine (2-NA). Treatment with 3-aminobiphenyl (3-ABP) and 1-naphthylamine (1-NA), both considered to be non-carcinogenic, were used as controls. The purpose of this study was: (1) to determine whether or not changes that occurred in the plasma protein patterns were specific to 4-ABP and/or other related carcinogenic arylamines; (2) to measure the time course in the changes of the major polypeptides during dosing and their resynthesis during a recovery period; and (3) to determine, by microsequencing, the biochemical identity of the affected proteins. The results indicate that only the most potent carcinogen, 4-ABP, had the effect of suppressing the expression of some proteins, while the other aromatic amines caused no discernible change in the 2DG patterns during a 12-week dosing period. The 4-ABP caused dramatic suppression of two sets of proteins. One set of three spots had an apparent molecular weight of 32.5 kDa, and a pI of 5.8-6.0. The major component in this group was identified as the beta-chain of haptoglobin. Expression of this protein decreased markedly during the first 2 weeks of treatment and recovered slowly after dosing stopped. Since haptoglobin functions to bind with free hemoglobin and facilitates its elimination from the blood stream, these results can be rationalized as a consequence of 4-ABP binding to hemoglobin in the erythrocyte, resulting in cell death and hemolysis. The 4-ABP modified hemoglobin then binds to haptoglobin and this tertiary complex is purged from the blood stream, resulting in the disappearance of free haptoglobin. A second set of spots (mol. wt., 65 kDa; pI, 6.5-6.6) disappeared much faster than the haptoglobin, and recovered more quickly. The major protein is about one-fifth the intensity of haptoglobin and appeared to be N

  15. Increased formation of carcinogenic PAH metabolites in fish promoted by nitrite

    International Nuclear Information System (INIS)

    Nitrite (NO2-), a highly reactive chemical species, accumulates in coastal waters as a result of pollution with nitrogenous waste and/or an imbalance in the bacterial processes of nitrification and denitrification. The present study probed the impact of nitrite (NO2-) on the metabolism of polycyclic aromatic hydrocarbons (PAHs) in fish. In a laboratory experiment, exposure of euryhaline fish, Oreochromis mossambicus to industrial effluents containing PAHs in the presence of NO2- enhanced the cytochrome P450-dependent biotransformation activity determined as 7-ethoxyresorufin-O-deethylase (EROD), by nearly 36% compared to the value observed in the absence of NO2- (50.2 ± 6.74 pmol resorufin min-1 g-1 liver). Fixed wavelength fluorescence measurements in bile revealed maximum enhancement to have occurred in the metabolites of benzo[a]pyrene, a carcinogenic PAH. Lasting, sublethal physiological deterioration was apparent in fish exposed simultaneously to an oil refinery effluent and NO2-, from the unremittingly decreasing liver somatic index, even after the withdrawal of the contaminants. - Nitrite increased formation of carcinogenic PAH metabolites in fish

  16. Antiproliferative effects of fluoxetine on colon cancer cells and in a colonic carcinogen mouse model.

    Directory of Open Access Journals (Sweden)

    Vinicius Kannen

    Full Text Available The antidepressant fluoxetine has been under discussion because of its potential influence on cancer risk. It was found to inhibit the development of carcinogen-induced preneoplastic lesions in colon tissue, but the mechanisms of action are not well understood. Therefore, we investigated anti-proliferative effects, and used HT29 colon tumor cells in vitro, as well as C57BL/6 mice exposed to intra-rectal treatment with the carcinogen N-methyl-N'-nitro-N-nitrosoguanidine (MNNG as models. Fluoxetine increased the percentage of HT29 cells in the G(0/G(1 phase of cell-cycle, and the expression of p27 protein. This was not related to an induction of apoptosis, reactive oxygen species or DNA damage. In vivo, fluoxetine reduced the development of MNNG-induced dysplasia and vascularization-related dysplasia in colon tissue, which was analyzed by histopathological techniques. An anti-proliferative potential of fluoxetine was observed in epithelial and stromal areas. It was accompanied by a reduction of VEGF expression and of the number of cells with angiogenic potential, such as CD133, CD34, and CD31-positive cell clusters. Taken together, our findings suggest that fluoxetine treatment targets steps of early colon carcinogenesis. This confirms its protective potential, explaining at least partially the lower colon cancer risk under antidepressant therapy.

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

    Science.gov (United States)

    Tomšík, Pavel

    2014-06-01

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

  18. Contribution of post-harvest agricultural paddy residue fires in the N.W. Indo-Gangetic Plain to ambient carcinogenic benzenoids, toxic isocyanic acid and carbon monoxide

    Science.gov (United States)

    Praphulla Chandra, Boggarapu; Sinha, Vinayak

    2016-04-01

    In the North West Indo-Gangetic Plain (N.W.IGP), large scale post-harvest paddy residue fires occur every year during the months of October-November. This anthropogenic perturbation causes contamination of the atmospheric environment with adverse impacts on regional air quality posing health risks for the population exposed to high concentrations of carcinogens such as benzene and toxic VOCs such as isocyanic acid. These gases and carbon monoxide are known to be emitted from biomass fires along with acetonitrile. Yet no long-term in-situ measurements quantifying the impact of this activity have been carried out in the N.W. IGP. Using high quality continuous online in-situ measurements of these gases at a strategic downwind site over a three year period from 2012 to 2014, we demonstrate the strong impact of this anthropogenic emission activity on ambient concentrations of these gases. In contrast to the pre-paddy harvest period, excellent correlation of benzenoids, isocyanic acid and CO with acetonitrile (a biomass burning chemical tracer); (r ≥ 0.82) and distinct VOC/acetonitrile emission ratios were observed for the post-paddy harvest period which was also characterized by high ambient concentrations of these species. The average concentrations of acetonitrile (1.62 ± 0.18 ppb), benzene (2.51 ± 0.28 ppb), toluene (3.72 ± 0.41 ppb), C8-aromatics (2.88 ± 0.30 ppb), C9-aromatics (1.55 ± 0.19 ppb) and CO (552 ± 113 ppb) in the post-paddy harvest periods were about 1.5 times higher than the annual average concentrations. For isocyanic acid, a compound with both primary and secondary sources, the concentration in the post-paddy harvest period was 0.97 ± 0.17 ppb. The annual average concentrations of benzene, a class A carcinogen, exceeded the annual exposure limit of 1.6 ppb at NTP mandated by the National Ambient Air Quality Standard of India (NAAQS). We show that mitigating the post-harvest paddy residue fires can lower the annual average concentration of

  19. Emissive Ion Thruster -EMIT Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A propulsion system is proposed that is based on acceleration of ions emitted from a thin, solid-state electrochemical ceramic membrane. This technology would...

  20. [Update on benzene: from industrial toxicant to environmental carcinogen].

    Science.gov (United States)

    Manno, Maurizio

    2013-01-01

    Benzene, an industrial chemical myelotoxic at high doses in workers, is now an almost ubiquitous pollutant. It is also a no-threshold genotoxic carcinogen causing acute leukemia and other lymphoaematological tumours. Although its mechanism of action has not been fully clarified, benzene toxicity and carcinogenicity depend on metabolic activation. Polymorphism of activating and detoxifying enzymes (CYP, GST, NQO1) may be critical, therefore, in modulating individual susceptibility to benzene. Further uncertainty factors in assessing low level benzene exposure are the limited sensitivity and specificity of most exposure biomarkers, the frequent coexposure to other volatile organic chemicals (VOC), and the presence of non occupational sources of exposure, such as cigarette smoke and veicular traffic. The aim of this presentation is to introduce the main current critical issues in the risk assessment and the biological monitoring of occupational exposure to benzene at low doses. PMID:24303704

  1. An assessment of the carcinogenic potential of ezetimibe using nonclinical data in a weight-of-evidence approach

    International Nuclear Information System (INIS)

    Ezetimibe blocks intestinal absorption of sterols via interaction with the Neimann-Pick C1-Like 1 (NPC1L1) transporter and is approved for use in the treatment of primary hyperlipidemia (heterozygous familial and non-familial), homozygous familial hypercholesterolemia, and homozygous sitosterolemia. A recently completed randomized clinical trial [simvastatin and ezetimibe in aortic stenosis (SEAS)] testing the effectiveness of VytorinTM (a combination of simvastatin and ezetimibe) in patients with aortic stenosis reported an unexpected safety finding: an increase in overall cancer incidence and cancer-associated mortality (all types) in the treated groups relative to the placebo control. A subsequent meta-analysis utilizing a much larger database from two ongoing clinical trials indicated that the observed findings in the SEAS trial were likely due to chance and not a true drug-induced effect. Nonetheless, it has been suggested by various commentators on the SEAS trial that ezetimibe may be carcinogenic. The extensive nonclinical database for ezetimibe was used to test the hypothesis that ezetimibe may be a direct or indirect carcinogen. Using two different in silico approaches, ezetimibe showed no structural alerts for genetic toxicity or carcinogenicity. Ezetimibe was not genotoxic in two reverse mutation assays, one in vitro clastogenicity assay, and two mouse micronucleus assays. No evidence of proliferative lesions was observed in three species in studies of 1-12 months in duration. Ezetimibe was not carcinogenic in standard 2-year bioassays in mice and rats. Additionally, in these 2-year bioassays, no drug-related non-neoplastic lesions were noted. The absence of drug-induced non-neoplastic or proliferative lesions in these studies indicates that ezetimibe treatment was not associated with findings characteristic of carcinogens (i.e., DNA reactivity or cell proliferation) Administration of pharmacologic doses of ezetimibe to mice did not alter hepatic

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

    International Nuclear Information System (INIS)

    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 C3H 10T12 Cell Transformation; Mechanisms of Radiation-Induced Cell Transformation; and Use of Cell Transformation Assays for Carcinogen Testing

  3. The role of pancreatic islets in experimental pancreatic carcinogenicity.

    OpenAIRE

    ISHIKAWA, O; Ohigashi, H.; Imaoka, S.; Nakai, I.; Mitsuo, M.; Weide, L. van der; Pour, P. M.

    1995-01-01

    Our previous studies have suggested that the presence of intact islets is essential for the induction of pancreatic exocrine tumors in the Syrian hamster model. To validate this, we investigated the effect of the carcinogen, N-nitrosobis(2-oxo-propyl)amine (BOP) in hamsters, in which homologous isolated intact islets were transplanted into the submandibular gland (SMG). Freshly isolated pure islets from hamster donors were transplanted into the left SMG of 20 female host hamsters. Ten of thes...

  4. Cannabis and tobacco smoke are not equally carcinogenic

    OpenAIRE

    Melamede Robert

    2005-01-01

    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 c...

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

    OpenAIRE

    Gasser Robin B; Smout Michael J; Sripa Manop; Sripa Banchob; Mulvenna Jason; Pinlaor Porntip; Laha Thewarach; Brindley Paul J; Loukas Alex

    2007-01-01

    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 tra...

  6. Cellular-signaling pathways unveil the carcinogenic potential of chemicals.

    Science.gov (United States)

    Hendriks, Giel; van de Water, Bob; Schoonen, Willem; Vrieling, Harry

    2013-06-01

    Most of the current in vitro carcinogenicity assays assess the potential carcinogenic properties of chemicals through the detection of inflicted DNA damage or subsequent chromosome damage and gene mutations. Unfortunately, these assays generally do not provide mechanistic insight into the reactive properties of a chemical. Upon chemical-induced damage of biomolecules, molecular sensors will activate general and damage-specific cellular response pathways that provide protection against the (geno)toxic and potential carcinogenic properties of chemicals. These cellular defense mechanisms include activation of cell-cycle checkpoints, DNA repair systems and induction of apoptosis or necrosis. Visualization of activated cellular-signaling pathways forms a powerful means to readily detect the genotoxic potential of chemical compounds and simultaneously gain insight into their reactive properties. Over the past years, various in vitro reporter assays have been developed that monitor activation of general and more specific cellular-signaling pathways, including the GreenScreen HC and ToxTracker assays. In this review we provide a perspective on how we can exploit activation of cellular signaling pathways to shed light on the mode of action of the chemical exposure and to develop sophisticated mechanism-based in vitro assays for cancer risk assessment. PMID:23339022

  7. Workplace carcinogen and pesticide exposures in Costa Rica.

    Science.gov (United States)

    Partanen, Timo; Chaves, Jorge; Wesseling, Catharina; Chaverri, Fabio; Monge, Patricia; Ruepert, Clemens; Aragón, Aurora; Kogevinas, Manolis; Hogstedt, Christer; Kauppinen, Timo

    2003-01-01

    The CAREX data system converts national workforce volumes and proportions of workers exposed to workplace carcinogens into numbers of exposed in 55 industrial categories. CAREX was adapted for Costa Rica for 27 carcinogens and seven groups of pesticides. Widespread workplace carcinogens in the 1.3 million workforce of Costa Rica are solar radiation (333,000 workers), diesel engine exhaust (278,000), environmental tobacco smoke (71,000), hexavalent chromium compounds (55,000), benzene (52,000), wood dust (32,000), silica dust (27,000), lead and inorganic lead compounds (19,000), and polycyclic aromatic compounds (17,000). The most ubiquitous pesticides were paraquat and diquat (175,000), mancozeb, maneb, and zineb (49,000), chlorothalonil (38,000), benomyl (19,000), and chlorophenoxy herbicides (11,000). Among women, formaldehyde, radon, and methylene chloride overrode pesticides, chromium, wood dust, and silica dust in numbers of exposed. High-risk sectors included agriculture, construction, personal and household services, land and water transport and allied services, pottery and similar industries, woodworks, mining, forestry and logging, fishing, manufacturing of electrical machinery, and bar and restaurant personnel. PMID:12848237

  8. Potential co-carcinogens in the uranium mine environment

    International Nuclear Information System (INIS)

    Studies of increased incidence of lung cancer in uranium miners have focussed on the relationship between lung cancer and miners' exposure to radon daughters and smoking. However, epidemiologic analyses of uranium miner populations also include the effects of exposure to external gamma rays, long-lived alpha emitters and other non-radioactive workplace contaminants. The diversity and variability of miner exposures to potentially carcinogenic substances and combinations of substances, and the natural difficulties involved in the study of lung cancer in human populations, make the assessment of the relative effects of causative agents difficult if not impossible. Moreover, concentrations of most of the substances have rarely been measured in mine environments, and data on human response to these substances is sparse. Nonetheless, research on the potential effects of such substances is required to understand the potential hazards in the mining environment. This paper examines the potential carcinogenic and co-carcinogenic effects of agents other than ionizing radiation, which may currently be present in uranium mine atmospheres

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

    Science.gov (United States)

    Weihrauch, M R; Diehl, V

    2004-10-01

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

  10. Modelling the dispersion of vehicle-emitted pollutants

    Energy Technology Data Exchange (ETDEWEB)

    McCrae, I.S.; Hamilton, R.S.; Revitt, D.M. (Middlesex Polytechnic, Middlesex (GB)); Harrop, D.O. (Tottenham College, London (GB))

    1988-01-01

    It is well known that certain vehicle-generated air pollutants may have adverse effects on human health, ecosystems and amenity. For many years, carbon monoxide and lead were the pollutants which received most attention. However, other problems have been identified, principally the role of nitrogen oxides in producing acid rain, the mutagenic and carcinogenic effects of polyaromatic hydrocarbons and the darkness of diesel-emitted smoke. The magnitude of some of the problems has been compounded by changes in engine design and fuel composition. An understanding of the impact of vehicle-emitted pollutants on the environment requires a knowledge of the processes which control their transport through the atmosphere. Short-range transport processes are best investigated using field data collected near to a rural motorway since in that situation the source is a well-defined line to which standard mathematical modelling techniques can be applied and non-vehicle sources of pollution are reduced to a minimum. This paper examines the use of desk-top and computer-based techniques to predict CO concentrations.

  11. 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. PMID:25716480

  12. Carcinogenic and Non-Carcinogenic Assessment of Phthalates Exposure Through Consumption of Bottled Water During the Storage Time

    OpenAIRE

    M Zare Jeddi; Rastkari, N.; R Ahmadkhaniha; M Alimohammadi; M. Yunesian

    2015-01-01

    Background and Objectives: Bottles for packaging drinking water represent one of the most popular uses of plastic and polymer additives. Recently, public concerns related to possibility of exposure to chemicals through the consumption of polyethylene terephthalate bottled water has caused great concern to consumers. Phthalate esters, as a class of these compounds, are often classified as endocrine disruptors and one of them is a possible carcinogen for human. The aim of this study was to dete...

  13. ORGANIC LIGHT EMITTING DIODE (OLED

    Directory of Open Access Journals (Sweden)

    Aririguzo Marvis Ijeaku

    2015-09-01

    Full Text Available An Organic Light Emitting Diode (OLED is a device composed of an organic layer that emits lights in response to an electrical current. Organic light emitting diodes have advanced tremendously over the past decades. The different manufacturing processes of the OLED itself to several advantages over flat panel displays made with LCD technology which includes its light weight and flexible plastic substrates, wider viewing angles, improved brightness, better power efficiency and quicker response time. However, its drawbacks include shorter life span, poor color balance, poor outdoor performance, susceptibility to water damage etc.The application of OLEDs in electronics is on the increase on daily basics from cameras to cell phones to OLED televisions, etc. Although OLEDs provides prospects for thinner, smarter, lighter and ultraflexible electronics displays, however, due to high cost of manufacturing, it is not yet widely used.

  14. New clues on carcinogenicity-related substructures derived from mining two large datasets of chemical compounds.

    Science.gov (United States)

    Golbamaki, Azadi; Benfenati, Emilio; Golbamaki, Nazanin; Manganaro, Alberto; Merdivan, Erinc; Roncaglioni, Alessandra; Gini, Giuseppina

    2016-04-01

    In this study, new molecular fragments associated with genotoxic and nongenotoxic carcinogens are introduced to estimate the carcinogenic potential of compounds. Two rule-based carcinogenesis models were developed with the aid of SARpy: model R (from rodents' experimental data) and model E (from human carcinogenicity data). Structural alert extraction method of SARpy uses a completely automated and unbiased manner with statistical significance. The carcinogenicity models developed in this study are collections of carcinogenic potential fragments that were extracted from two carcinogenicity databases: the ANTARES carcinogenicity dataset with information from bioassay on rats and the combination of ISSCAN and CGX datasets, which take into accounts human-based assessment. The performance of these two models was evaluated in terms of cross-validation and external validation using a 258 compound case study dataset. Combining R and H predictions and scoring a positive or negative result when both models are concordant on a prediction, increased accuracy to 72% and specificity to 79% on the external test set. The carcinogenic fragments present in the two models were compared and analyzed from the point of view of chemical class. The results of this study show that the developed rule sets will be a useful tool to identify some new structural alerts of carcinogenicity and provide effective information on the molecular structures of carcinogenic chemicals. PMID:26986491

  15. Interference of spontaneously emitted photons

    CERN Document Server

    Beige, A; Pachos, J; Beige, Almut; Schoen, Christian; Pachos, Jiannis

    2002-01-01

    We discuss an experimental setup where two laser-driven atoms spontaneously emit photons and every photon causes a ``click'' at a point on a screen. By deriving the probability density for an emission into a certain direction from basic quantum mechanical principles we predict a spatial interference pattern. Similarities and differences with the classical double-slit experiment are discussed.

  16. Interference of spontaneously emitted photons

    OpenAIRE

    Beige, Almut; Schoen, Christian; Pachos, Jiannis

    2001-01-01

    We discuss an experimental setup where two laser-driven atoms spontaneously emit photons and every photon causes a ``click'' at a point on a screen. By deriving the probability density for an emission into a certain direction from basic quantum mechanical principles we predict a spatial interference pattern. Similarities and differences with the classical double-slit experiment are discussed.

  17. Effect of Radiation on the Functions of Carcinogenic Viruses

    International Nuclear Information System (INIS)

    When carcinogenic viruses are irradiated under suitable experimental conditions with ultra-violet rays or ionizing radiation, the various viral functions can be dissociated and virions defective in certain functions can be obtained. These defects are real mutations; they are passed on to subsequent generations provided the virions affected remain capable of reproduction. It has been possible to obtain various types of mutant, e.g. hyper producers of virions, non-productive transformers, non-transforming producers. The production of these mutants opens up certain experimental possibilities with regard to the transformation mechanism and the possible consequences of irradiation in vivo. Attention will be devoted in particular to the increased oncogenic capability in vivo which is sometimes observed in pre-irradiated viruses, and also to the consequences of this effect in the radiotherapy of certain malignant infections. These studies are also of interest for analysing the structure of the viral genome and throwing light on that fraction of the genome which is responsible for the transforming capacity. In the case of small viruses with a single DNA molecule (polyoma, SV-40) it has been possible to measure the fraction of the molecule responsible for the transforming capacity. In the case of the Rous virus the experiments suggest that the viral RNA is made up of sub-units capable of independent replication, the transforming capacity being possessed by only one of these sub-units. The induced defect may reveal the presence of transforming capacity in a virus considered as non- oncogenic because the transformed cells are usually eliminated by the infective process. In this way irradiation could render carcinogenic a virus which is not carcinogenic under normal conditions. The paper covers work done at the various viral radiobiology laboratories of the Radium Institute during the last two years. (author)

  18. Chemical speciation of trace metals emitted from Indonesian peat fires for health risk assessment

    Science.gov (United States)

    Betha, Raghu; Pradani, Maharani; Lestari, Puji; Joshi, Umid Man; Reid, Jeffrey S.; Balasubramanian, Rajasekhar

    2013-03-01

    Regional smoke-induced haze in Southeast Asia, caused by uncontrolled forest and peat fires in Indonesia, is of major environmental and health concern. In this study, we estimated carcinogenic and non-carcinogenic health risk due to exposure to fine particles (PM2.5) as emitted from peat fires at Kalimantan, Indonesia. For the health risk analysis, chemical speciation (exchangeable, reducible, oxidizable, and residual fractions) of 12 trace metals (Al, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Ti, V and Zn) in PM2.5 was studied. Results indicate that Al, Fe and Ti together accounted for a major fraction of total metal concentrations (~ 83%) in PM2.5 emissions in the immediate vicinity of peat fires. Chemical speciation reveals that a major proportion of most of the metals, with the exception of Cr, Mn, Fe, Ni and Cd, was present in the residual fraction. The exchangeable fraction of metals, which represents their bioavailability, could play a major role in inducing human health effects of PM2.5. This fraction contained carcinogenic metals such as Cd (39.2 ng m- 3) and Ni (249.3 ng m- 3) that exceeded their WHO guideline values by several factors. Health risk estimates suggest that exposure to PM2.5 emissions in the vicinity of peat fires poses serious health threats.

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

    International Nuclear Information System (INIS)

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

  20. Prostaglandin hydroperoxidase-catalyzed activation of certain N-substituted aryl renal and bladder carcinogens

    OpenAIRE

    Zenser, T V; Cohen, S M; Mattammal, M. B.; Wise, R. W.; Rapp, N. S.; Davis, B B

    1983-01-01

    Certain carcinogens are thought to induce renal and bladder cancer following metabolic activation. We propose a model system for this activation and provide supporting experimental evidence. This model proposes that renal and bladder carcinogens' entry into the urinary tract is facilitated, that carcinogens are activated by the prostaglandin hydroperoxidase activity of prostaglandin endoperoxide synthetase (PES), and that activation results in covalent binding to nucleic acids which can initi...

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

    Directory of Open Access Journals (Sweden)

    Hiroshi Matsumoto

    2009-11-01

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

  2. Ochratoxin A carcinogenicity involves a complex network of epigenetic mechanisms.

    Science.gov (United States)

    Marin-Kuan, Maricel; Cavin, Christophe; Delatour, Thierry; Schilter, Benoît

    2008-08-01

    Ochratoxin A (OTA) is a mycotoxin occurring in a wide range of food products. Because of the limitation of human epidemiological data, the safety significance of OTA in food has to rely on animal data, with renal toxicity and carcinogenicity being considered the pivotal effects. The elucidation of the mechanism of action would improve the use of experimental animal data for risk assessment. Direct genotoxicity versus epigenetic mechanisms appears to be a key question. In the present review, the increasingly documented epigenetic cellular effects of OTA and their potential toxicological relevance are discussed. The information available suggests that OTA is unlikely to act through a single, well-defined mechanism of action. Instead, it is proposed that a network of interacting epigenetic mechanisms, including protein synthesis inhibition, oxidative stress and the activation of specific cell signalling pathways, is responsible for OTA carcinogenicity. From a risk assessment perspective, it has to be noted that the mechanisms proposed above depend mainly upon gene expression and enzyme activation, and are, therefore, likely to be thresholded. PMID:18649906

  3. Carcinogenic effects ofcircadian disruption:an epigenetic viewpoint

    Institute of Scientific and Technical Information of China (English)

    Abbas Salavaty

    2015-01-01

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

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

    International Nuclear Information System (INIS)

    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 (106 particles/cm3) to what would be expected from wisps of smoke (108 particles/cm3). 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

  5. Systems biology perspectives on the carcinogenic potential of radiation

    International Nuclear Information System (INIS)

    This review focuses on recent experimental and modeling studies that attempt to define the physiological context in which high linear energy transfer (LET) radiation increases epithelial cancer risk and the efficiency with which it does so. Radiation carcinogenesis is a two-compartment problem: ionizing radiation can alter genomic sequence as a result of damage due to targeted effects (TE) from the interaction of energy and DNA; it can also alter phenotype and multicellular interactions that contribute to cancer by poorly understood non-targeted effects (NTE). Rather than being secondary to DNA damage and mutations that can initiate cancer, radiation NTE create the critical context in which to promote cancer. Systems biology modeling using comprehensive experimental data that integrates different levels of biological organization and time-scales is a means of identifying the key processes underlying the carcinogenic potential of high-LET radiation. We hypothesize that inflammation is a key process, and thus cancer susceptibility will depend on specific genetic predisposition to the type and duration of this response. Systems genetics using novel mouse models can be used to identify such determinants of susceptibility to cancer in radiation sensitive tissues following high-LET radiation. Improved understanding of radiation carcinogenesis achieved by defining the relative contribution of NTE carcinogenic effects and identifying the genetic determinants of the high-LET cancer susceptibility will help reduce uncertainties in radiation risk assessment

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1981-09-01

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

  7. Neoplastic transformation of human diploid fibroblast cells by chemical carcinogens

    Science.gov (United States)

    Kakunaga, Takeo

    1978-01-01

    Cultured fibroblast cells derived from a skin biopsy sample taken from normal human adult were exposed to a potent carcinogen, 4-nitroquinoline 1-oxide. Alterations of cell growth pattern such as higher density and piling up of cells were noticed in some fractions of cultures that were successively subcultured after nitroquinoline oxide treatment. Morphologically altered cells retained this growth pattern and became established lines of transformed cells without showing the limited life-span characteristic of normal cells in culture. The transformed cells showed a higher saturation density and the ability to grow in soft agar, properties that are usually correlated with neoplastic transformation of cells in culture. Selection of preexisting transformed human cells as a mechanism of this observed transformation seemed unlikely because clones of these normal cells could also be used to assess the transforming effect of nitroquinoline oxide. Preliminary results suggest that numerous cell divisions were required for the development of the transformation after nitroquinoline oxide treatment of these human cells. When the transformed cell lines were injected subcutaneously into nude (athymic) mice, solid tumors were produced at the site of inoculation. Treatment with N-methyl-N′-nitro-N-nitrosoguanidine also induced cell transformation, in a manner similar to treatment with nitroquinoline oxide. However, transformation was not induced with (i) 4-aminoquinoline 1-oxide (a noncarcinogenic derivative of 4-nitroquinoline 1-oxide), (ii) 3-methylcholanthrene (a carcinogen that cannot be metabolically activated by the target cells employed), or (iii) the solvent dimethyl sulfoxide. Images PMID:418410

  8. Identification of 5-lipoxygenase and microsomal prostaglandin E2 synthase-1 as functional targets of the anti-inflammatory and anti-carcinogenic garcinol

    OpenAIRE

    Koeberle, Andreas; Northoff, Hinnak; Werz, Oliver

    2009-01-01

    Abstract Garcinol (camboginol) from the fruit rind of Guttiferae species shows anti-carcinogenic and anti-inflammatory properties, but the underlying molecular mechanisms are unclear. Here we show that garcinol potently interferes with 5-lipoxygenase (EC 7.13.11.34) and microsomal prostaglandin (PG)E2 synthase (mPGES)-1 (EC 5.3.99.3), enzymes that play pivotal roles in inflammation and tumorigenesis. In cell-free assays, garcinol inhibited the activity of purified 5-lipoxygenase an...

  9. Organic Light-Emitting Transistors

    OpenAIRE

    Karg, Siegfried; Rost-Bietsch, Constance; Riess, Walter; Loi, Maria Antonietta; Murgia, Mauro; Muccini, Michele

    2005-01-01

    A light-emitting OFET with pronounced ambipolar current characteristic has been prepared by co-evaporation of α-quinquethiophene (α-5T) as hole-transport material and ditridecyl-perylene-tetracarboxylic diimide (P13) as electron-transport material. The light intensity is controlled by both the drain-source voltage VDS and the gate voltage VG. Here, we demonstrate the general concept of adjusting electron and hole mobilities by co-evaporation of two different organic semiconductors.

  10. Molecular biomarkers of oxidative stress associated with bromate carcinogenicity

    International Nuclear Information System (INIS)

    Potassium bromate (KBrO3) is a chemical oxidizing agent found in drinking water as a disinfection byproduct of surface water ozonation. Chronic exposures to KBrO3 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 KBrO3-induced cancer, male F344 rats were administered KBrO3 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 (18O) labeled KBrO3 was administered to male rats by oral gavage and tissues were analyzed for 18O deposition. Tissue enrichment of 18O was observed at 5 and 24 h post-KBr18O3 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 18O deposition between 0.25 and 50 mg/L (equivalent dose) KBr18O3 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

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

    International Nuclear Information System (INIS)

    Cancer prevention has to be based on robust biological and epidemiological data, therefore its reappraisal becomes mandatory in view of recent progress in the understanding of carcinogenesis. The first phase of the carcinogenic process, that of initiation, is generally associated with mutation; however the role of extrinsic mutagens is less critical than was thought two decades ago. During intracellular oxygen metabolism, reactive oxygen species (R.O.S.) are made which are potent mutagens. Defense mechanisms against these intrinsic mutagens include scavenger and enzymatic systems which destroy them (catalase, superoxide dismutase). When the radiation dose is low, DNA repair is very effective as well as the elimination of cells with unrepaired or bad repaired DNA. Therefore a small increase in the number of R.O.S., such as that caused by a small dose of radiation has most probably no significant effect on the risk of DNA damage. These conclusions are consistent with the concept of a practical threshold. The second phase, that of promotion, appears to be the key one. During the promotion phase, initiated cells must acquire new properties (immortalization, release of angiogenic factors, resistance to hypoxia, etc.) in order to become pre-cancerous. This evolution is due to the accumulation in the genome of 6 to 10 new alteration defects. In the clone of initiated cells, the occurrence in one cell of a mutation or an epigenetic event gives birth to a sub clone. There is a Darwinian type competition between the sub clones and those with the more rapid growth because dominant (the acceleration of the growth rate can be due to shorter cell cycles or to an alleviation of cell proliferation exerted by the neighboring cells or the microenvironment). In the dominant sub clones new genomic events provoke the appearance of new sub clones growing more rapidly and having greater autonomy. The process is very slow because the specific genetic events that favour this evolution

  12. Contribution of post-harvest agricultural paddy residue fires in the N.W. Indo-Gangetic Plain to ambient carcinogenic benzenoids, toxic isocyanic acid and carbon monoxide.

    Science.gov (United States)

    Chandra, B P; Sinha, Vinayak

    2016-03-01

    In the north west Indo-Gangetic Plain (N.W.IGP), large scale post-harvest paddy residue fires occur every year during the months of October-November. This anthropogenic perturbation causes contamination of the atmospheric environment with adverse impacts on regional air quality posing health risks for the population exposed to high concentrations of carcinogens such as benzene and toxic VOCs such as isocyanic acid. These gases and carbon monoxide are known to be emitted from biomass fires along with acetonitrile. Yet no long-term in-situ measurements quantifying the impact of this activity have been carried out in the N.W. IGP. Using high quality continuous online in-situ measurements of these gases at a strategic downwind site over a three year period from 2012 to 2014, we demonstrate the strong impact of this anthropogenic emission activity on ambient concentrations of these gases. In contrast to the pre-paddy harvest period, excellent correlation of benzenoids, isocyanic acid and CO with acetonitrile (a biomass burning chemical tracer); (r≥0.82) and distinct VOC/acetonitrile emission ratios were observed for the post-paddy harvest period which was also characterized by high ambient concentrations of these species. The average concentrations of acetonitrile (1.62±0.18ppb), benzene (2.51±0.28ppb), toluene (3.72±0.41ppb), C8-aromatics (2.88±0.30ppb), C9-aromatics (1.55±0.19ppb) and CO (552±113ppb) in the post-paddy harvest periods were about 1.5 times higher than the annual average concentrations. For isocyanic acid, a compound with both primary and secondary sources, the concentration in the post-paddy harvest period was 0.97±0.17ppb. The annual average concentrations of benzene, a class A carcinogen, exceeded the annual exposure limit of 1.6ppb at NTP mandated by the National Ambient Air Quality Standard of India (NAAQS). We show that mitigating the post-harvest paddy residue fires can lower the annual average concentration of benzene and ensure

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

    Science.gov (United States)

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

    2015-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1983-01-01

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

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

    DEFF Research Database (Denmark)

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

    2003-01-01

    Bracken (Pteridium aquilinum (L.) Kuhn) is a common fern found on all continents except Antarctica. It is under suspicion of causing cancer among people who utilizes it as food. The main carcinogenic compound is thought to be the water-soluble compound ptaquiloside. Ptaquiloside-uptake may occur....... The ptaquiloside-content in the standing biomass, which could be transferred to the soil by the end of the growing season, ranged between 10 and 260 mgm2, with nine sites having ptaquiloside loads over 100 mgm2. The carbon-content in the O-horizon, the precipitation, the amount of Bracken-litter, the...... turnover rate and the size of Bracken-stands determined the ptaquiloside-content in the soil materials while the content in fronds was found to be a function of the frond-height and the light-exposure in the ecosystem....

  16. Bioavailability of platinum emitted from automobile exhaust.

    Science.gov (United States)

    Artelt, S; Kock, H; Nachtigall, D; Heinrich, U

    1998-08-01

    A model substance was used which is similar in respect to platinum content of exhaust particles emitted from a three-way-catalytic converter equipped engine. The bioavailability of platinum from such exhaust particles and the kind of platinum species formed in vivo were assessed. An in vitro solubility test showed a solubility of approximately 10 percent of platinum content of the model substance in physiological sodium chloride solution. Two short-term animal studies (8 days) were performed. In all examined rat tissues and body fluids platinum could be detected. In addition, the contribution of the overall bioavailability caused by swallowing a certain amount of the intratracheally applied platinum was evaluated by oral application. It was very low. An analytical method was developed to determine platinum species. Synthetic samples (matrix with a platinum standard solution) were analysed. In rat bronchoalveolar lavage spiked with a platinum standard solution only low molecular complexed platinum was found whereas in rat blood plasma all platinum was bound to proteins. In ongoing studies, the model substance is being tested in a three month rat inhalation study. PMID:9820662

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

    Science.gov (United States)

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

    2000-01-01

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

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

    NARCIS (Netherlands)

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

    2010-01-01

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

  19. Study of isotopic tracing related with mechanism of cancer caused by carcinogenic substance

    International Nuclear Information System (INIS)

    In order to understand the mechanism of cancer caused by carcinogenic substance, a project using 41Ca as tracer and accelerator mass spectrometry (AMS) as measurement method to investigate the origin of the increased Ca2+ when the cells are exposed to carcinogenic substances is being undertaken. Several results as bellow have been obtained

  20. Carcinogenic potential of some pesticides in a medium-term multi-organ bioassay in rats.

    Science.gov (United States)

    Hasegawa, R; Cabral, R; Hoshiya, T; Hakoi, K; Ogiso, T; Boonyaphiphat, P; Shirai, T; Ito, N

    1993-05-28

    The carcinogenic potential of 5 pesticides was analyzed using a medium-term multi-organ bioassay for carcinogenicity. Male F344 rats were initially treated with 3 known carcinogens (diethylnitrosamine, N-methyl-N-nitrosourea and N-bis(2-hydroxypropyl)nitrosamine) during a period of 4 weeks to induce neoplastic changes in a variety of organs, and then given one of 5 pesticides in the diet for a further 16 weeks. Neoplastic and pre-neoplastic lesions were found in the thyroid, kidney and urinary bladder with propineb, in the forestomach, kidney and thyroid with captan and folpet. The number of glutathione S-transferase placental-form-positive liver-cell foci was significantly increased in the captan- and phosmet-treated groups. Based on these findings, captan and propineb can be considered as carcinogens and carcinogenicity is suspected for folpet and phosmet. These results are in concordance with reported long-term carcinogenicity for captan, folpet and propineb. Daminozide was considered not to be carcinogenic. Thus, the present assay of 20 weeks' duration is useful for the prediction of potential carcinogens. PMID:8509224

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

    Science.gov (United States)

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

    2016-01-01

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

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

    Science.gov (United States)

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

    2016-01-01

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

  3. The International Agency for Research on Cancer (IARC) evaluation of the carcinogenicity of outdoor air pollution:focus on China

    Institute of Scientific and Technical Information of China (English)

    Dana Loomis; Wei Huang; Guosheng Chen

    2014-01-01

    The International Agency for Research on Cancer (IARC) has classified outdoor air pol ution and the particulate matter (PM) in outdoor air pol ution as carcinogenic to humans, as based on sufficient evidence of carcinogenicity in humans and experimental animals and strong support by mechanistic studies. The data with important contributions to the evaluation are reviewed, highlighting the data with particular relevance to China, and implications of the evaluation with respect to China are discussed. The air pol ution levels in Chinese cities are among the highest observed in the world today and frequently exceed health-based national and international guidelines. Data from high-quality epidemiologic studies in Asia, Europe, and North America consistently show positive associations between lung cancer and PM exposure and other indicators of air pol ution, which persist after adjustment for important lung cancer risk factors, such as tobacco smoking. Epidemiologic data from China are limited but nevertheless indicate an increased risk of lung cancer associated with several air pol utants. Excess cancer risk is also observed in experimental animals exposed to pol uted outdoor air or extracted PM. The exposure of several species to outdoor air pollution is associated with markers of genetic damage that have been linked to increased cancer risk in humans. Numerous studies from China, especially genetic biomarker studies in exposed populations, support that the polluted air in China is genotoxic and carcinogenic to humans. The evaluation by IARC indicates both the need for further research into the cancer risks associated with exposure to air pol ution in China and the urgent need to act to reduce exposure to the population.

  4. The International Agency for Research on Cancer (IARC evaluation of the carcinogenicity of outdoor air pollution: focus on China

    Directory of Open Access Journals (Sweden)

    Dana Loomis

    2014-04-01

    Full Text Available The International Agency for Research on Cancer (IARC has classified outdoor air pollution and the particulate matter (PM in outdoor air pollution as carcinogenic to humans, as based on sufficient evidence of carcinogenicity in humans and experimental animals and strong support by mechanistic studies. The data with important contributions to the evaluation are reviewed, highlighting the data with particular relevance to China, and implications of the evaluation with respect to China are discussed. The air pollution levels in Chinese cities are among the highest observed in the world today and frequently exceed health-based national and international guidelines. Data from high-quality epidemiologic studies in Asia, Europe, and North America consistently show positive associations between lung cancer and PM exposure and other indicators of air pollution, which persist after adjustment for important lung cancer risk factors, such as tobacco smoking. Epidemiologic data from China are limited but nevertheless indicate an increased risk of lung cancer associated with several air pollutants. Excess cancer risk is also observed in experimental animals exposed to polluted outdoor air or extracted PM. The exposure of several species to outdoor air pollution is associated with markers of genetic damage that have been linked to increased cancer risk in humans. Numerous studies from China, especially genetic biomarker studies in exposed populations, support that the polluted air in China is genotoxic and carcinogenic to humans. The evaluation by IARC indicates both the need for further research into the cancer risks associated with exposure to air pollution in China and the urgent need to act to reduce exposure to the population

  5. Taxonomy, biology, and clinical aspects of Fusarium species.

    OpenAIRE

    Nelson, P E; Dignani, M.C.; Anaissie, E J

    1994-01-01

    There are several taxonomic systems available for identifying Fusarium species. The philosophy used in each taxonomic system is discussed as well as problems encountered in working with Fusarium species in culture. Fusarium species are toxigenic, and the mycotoxins produced by these organisms are often associated with animal and human diseases. The implications for the association of the carcinogens, fumonisins, produced by Fusarium moniliforme and other Fusarium species with human diseases a...

  6. The dose-effect relationship and the estimation of carcinogen effects of low dose of ionizing radiation

    International Nuclear Information System (INIS)

    The carcinogen risks of an exposure to ionizing radiation have been evaluated by numerous epidemiological studies between 0.2 and 5 Sv. But the field of doses that concerns the human health is generally under a decade of mSv. The epidemiological studies do not detect any effect for doses under 100 mSv, either there is not or the statistical power of inquiries is not sufficient to detect them. Progress in radiobiology has shown that a cell is not passively affected by the accumulation of lesions induced by ionizing radiation. It react through at least three mechanisms: first, by fighting against reactive oxygen species (R.O.S.) generated by ionizing radiation and by oxidative stress, secondly, by eliminating injured cells (mutated or instable), through two mechanisms: apoptosis which can be initiated by doses as low as a few mSv, thus eliminating cells with genomes that have been damaged or mis-repaired, death of cells during mitosis when lesions have not been repaired, thirdly by stimulating or activating DNA repair systems following slightly higher doses of about ten mSv. About radio-carcinogenesis, with regard to tissue, the mechanisms which govern embryogenesis and direct tissue repair after injury appear to play also an important role in the control of cell proliferation. This is particularly important when a transformed cell is surrounded by normal cells. These mechanisms could explain the lower efficacy of heterogeneous irradiation as well as the absence of a carcinogenic effect in humans or experimental animals contaminated by small quantities of alpha emitter radionuclides. The latter data suggest the existence of a threshold. Immuno-surveillance systems are able to eliminate clones of transformed cells as is shown by tumor cell transplants. These data show that it is not justified to use linear no-threshold relationship to assess the carcinogenic risk of low doses from observations made for doses from .2 to 5 Sv since for the same dose increment the

  7. Formation and persistence of DNA adducts from the carcinogen N-hydroxy-2-acetylaminofluorene in rat mammary gland in vivo

    International Nuclear Information System (INIS)

    The rat mammary carcinogen, N-hydroxy-2-acetylaminofluorene (N-hydroxy-2-AAF), has been proposed to be metabolically activated by mammary cytosolic N,O-acetyltransferase to a DNA binding species. To test this hypothesis, adult female Sprague-Dawley derived CD rats were treated, i.p., with 4.0 mg/kg [ring-3H]N-hydroxy-2-AAF. After 4 h, 1, 3, 14, and 28 days, the animals were killed, the mammary epithelium DNA was isolated and the carcinogen-deoxyribonucleoside adducts present were analyzed by high pressure liquid chromatography. At each time, only one adduct was detected and it was chromatographically identical to N-(deoxyguanosin-8-yl)-2-aminofluorene. The level of the adduct was maximal at 4 h (1.5 adducts/10(6) nucleotides) and then decreased, following first order kinetics with a t1/2 of 14.2 days. The detection of a single non-acetylated aminofluorene adduct is consistent with N,O-acyltransferase being involved in the metabolic activation of N-hydroxy-2-AAF in the rat mammary gland

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

    International Nuclear Information System (INIS)

    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

  9. Magnetic polyethyleneimine (PEI) microcapsules as retrievable traps for carcinogen electrophiles formed in the gastrointestinal tract

    International Nuclear Information System (INIS)

    Semi-permeable magnetic microcapsules containing polyethyleneimine (PEI) have been developed as retrievable carcinogen traps. In vitro, the soluble core PEI and membrane both bound reactive substances of limited aqueous stability, such as from [14C]N-methyl-N-nitrosourea ([14C]NMU), and aqueous stable dyes of molecular weight up to 1000. The core/membrane location ratio of binding was dependent upon membrane characteristics of the microcapsule batch used. Microcapsules administered intragastrically to rats bound up to 0.006% of [14C]dimethylhydrazine ([14C]DMH) and 1.4% of [14C]NMU administered i.p. or intrarectally, respectively. Time-dependency of [14C]DMH binding was consistent with labelling of microcapsules within the small intestine. There were no detectable metabolites from [14C]DMH trapped within the colon, whereas binding of [14C]NMU indicated that microcapsules could bind transient species present within the colon in competition with the faecal bulk. These results indicate that this approach could be used to detect highly unstable and possibly genotoxic substances in situ, hitherto unknown, formed within the intestinal lumen. (author). 20 refs

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

    International Nuclear Information System (INIS)

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

  11. Looking at the carcinogenicity of human insulin analogues via the intrinsic disorder prism.

    Science.gov (United States)

    Redwan, Elrashdy M; Linjawi, Moustafa H; Uversky, Vladimir N

    2016-01-01

    Therapeutic insulin, in its native and biosynthetic forms as well as several currently available insulin analogues, continues to be the protein of most interest to researchers. From the time of its discovery to the development of modern insulin analogues, this important therapeutic protein has passed through several stages and product generations. Beside the well-known link between diabetes and cancer risk, the currently used therapeutic insulin analogues raised serious concerns due to their potential roles in cancer initiation and/or progression. It is possible that structural variations in some of the insulin analogues are responsible for the appearance of new oncogenic species with high binding affinity to the insulin-like growth factor 1 (IGF1) receptor. The question we are trying to answer in this work is: are there any specific features of the distribution of intrinsic disorder propensity within the amino acid sequences of insulin analogues that may provide an explanation for the carcinogenicity of the altered insulin protein? PMID:26983499

  12. 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.

  13. Childhood cancer: Overview of incidence trends and environmental carcinogens

    Energy Technology Data Exchange (ETDEWEB)

    Zahm, S.H.; Devesa, S.S. [National Cancer Inst., Rockville, MD (United States)

    1995-09-01

    An estimated 8000 children 0 to 14 years of age are diagnosed annually with cancer in the United States. Leukemia and brain tumors are the most common childhood malignancies, accounting for 30 and 20% of newly diagnosed cases, respectively. From 1975 to 1978 to 1987 to 1990, cancer among white children increased slightly from 12.8 to 14.1/100,000. Increases are suggested for leukemia, gliomas, and, to a much lesser extent, Wilms` tumor. There are a few well-established environmental causes of childhood cancer such as radiation, chemotherapeutic agents, and diethylstilbestrol. Many other agents such as electromagnetic fields, pesticides, and some parental occupational exposures are suspected of playing roles, but the evidence is not conclusive at this time. Some childhood exposures such as secondhand cigarette smoke may contribute to cancers that develop many years after childhood. For some exposures such as radiation and pesticides data suggest that children may be more susceptible to the carcinogenic effects than similarly exposed adults. 143 refs., 1 fig., 3 tabs.

  14. Urban air carcinogens and their effects on health

    Energy Technology Data Exchange (ETDEWEB)

    Lechner, J.F.

    1994-11-01

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

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

    Science.gov (United States)

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

    1996-01-01

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

  16. Biologically Inspired Organic Light-Emitting Diodes.

    Science.gov (United States)

    Kim, Jae-Jun; Lee, Jaeho; Yang, Sung-Pyo; Kim, Ha Gon; Kweon, Hee-Seok; Yoo, Seunghyup; Jeong, Ki-Hun

    2016-05-11

    Many animal species employ highly conspicuous traits as courtship signals for successful mating. Fireflies utilize their bioluminescent light as visual courtship signals. In addition to efficient bioluminescent light emission, the structural components of the firefly lantern also contribute to the enhancement of conspicuous optical signaling. Recently, these firefly lantern ultrastructures have attracted much interest and inspired highly efficient light management approaches. Here we report on the unique optical function of the hierarchical ultrastructures found in a firefly (Pyrocoelia rufa) and their biological inspiration of highly efficient organic light-emitting diode (OLED) applications. The hierarchical structures are comprised of longitudinal nanostructures and asymmetric microstructures, which were successfully replicated using geometry-guided resist reflow, replica molding, and polydimethylsiloxane (PDMS) oxidation. The external quantum efficiency (EQE) of the bioinspired OLEDs was enhanced by up to 61%. The bioinspired OLEDs clearly showed side-enhanced super-Lambertian emission with a wide-viewing angle. The highly efficient light extraction and wide-angle illumination suggest how the hierarchical structures likely improve the recognition of firefly optical courtship signals over a wide-angle range. At the same time, the biologically inspired designs provide a new paradigm for designing functional optical surfaces for lighting or display applications. PMID:27014918

  17. Low-emitting urban forests: A taxonomic methodology for assigning isoprene and monoterpene emission rates

    Science.gov (United States)

    Benjamin, Michael T.; Sudol, Mark; Bloch, Laura; Winer, Arthur M.

    Large-scale tree planting programs have been proposed, and are being implemented, as a means of reducing energy demand, mitigating urban heat islands, and improving air quality. However, many species of trees emit highly photochemically reactive hydrocarbons and the rates of such emissions can vary by four orders of magnitude, depending upon the tree species. Thus, planting of high-emitting trees species on a massive scale has the potential to adversely affect air quality rather than leading to improvement. However, the selection of low-emitting trees is difficult because emission rates have been experimentally determined for only a limited number of species. The present study describes a methodology for assigning biogenic emission rates based on taxonomic relationships. Using this methodology, direct emission measurements from 124 tree and shrub species found in the California South Coast Air Basin (SoCAB) are used to assign emission rates to 253 other species found in the SoCAB but for which there are no measured emission rates. The combined listing of 377 species is ranked according to total (isoprene and monoterpenes) biogenic emission rate on an hourly basis. Although the ranking of trees developed here is specific to Southern California, the methodology described can be applied to other geographic areas to assist in the planting of low-emitting urban forests.

  18. Polycyclic aromatic hydrocarbons and nitropolycyclic aromatic hydrocarbons in particulates emitted by motorcycles

    International Nuclear Information System (INIS)

    We determined eleven PAHs and four NPAHs in particulates and regulated pollutants (CO, CO2, HC, NOx, PM) exhausted from motorcycles to figure out the characteristics of motorcycle exhausts. Fluoranthene and pyrene accounted for more than 50% of the total detected PAHs. Among four detected NPAHs, 6-nitrochrysene and 7-nitrobenz[a]anthracene were the predominant NPAHs and were highly correlated relationship with their parent PAHs (R = 0.93 and 0.97, respectively). The PM and HC emissions tended to be close to the PAH emissions. NOx and NPAHs were negatively correlated. Despite their small engine size, motorcycles emitted much more PM and PAHs, showed stronger PAH-related carcinogenicity and indirect-acting mutagenicity, but weaker NPAH-related direct-acting mutagenic potency than automobiles. This is the first study to analyze both PAHs and NPAHs emitted by motorcycles, which could provide useful information to design the emission regulations and standards for motorcycles such as PM. -- Highlights: ► We characterized PAHs and NPAHs distribution in motorcycle exhausts. ► NPAHs concentrations were about three orders of magnitude lower than those of PAHs. ► We found larger amounts of PM and PAHs in exhaust of motorcycles than of automobiles. ► Motorcycles showed stronger PAH-related toxicity than automobiles. ► Motorcycles showed weaker NPAH-related direct-acting mutagenicity than automobiles. -- Control polycyclic aromatic hydrocarbons and nitropolycyclic aromatic hydrocarbon in particulates emitted by motorcycles due to their toxic potency

  19. Mutagens and carcinogens - Occurrence and role during chemical and biological evolution

    Science.gov (United States)

    Giner-Sorolla, A.; Oro, J.

    1981-01-01

    The roles of mutagenic and carcinogenic substances in early biologic evolution is examined, along with terrestrial and extraterrestrial sources of mutagens and carcinogens. UV solar radiation is noted to have served to stimulate prebiotic life while also causing harmful effects in plants and animals. Aromatic compounds have been found in meteorites, and comprise leukemogens, polycyclic hydrocarbons, and nitrasamine precursors. Other mutagenic sources are volcanoes, and the beginning of evolution with mutagenic substances is complicated by the appearance of malignancies due to the presence of carcinogens. The atmosphere of the Precambrian period contained both mutagens and early carcinogens and, combined with volcanic activity discharges, formed an atmospheric chemical background analogous to the background ionizing radiation. Carcinogenesis is concluded to be intrinsic to nature, having initiated evolution and, eventually, cancer cells.

  20. 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

  1. 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...

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

    Data.gov (United States)

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

  3. 78 FR 15020 - Report on Carcinogens Webinar on Pentachlorophenol; Notice of Public Webinar and Registration...

    Science.gov (United States)

    2013-03-08

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

  4. Carcinogenicity prediction of noncongeneric chemicals by augmented top priority fragment classification.

    Science.gov (United States)

    Casalegno, Mosè; Sello, Guido

    2016-04-01

    Carcinogenicity prediction is an important process that can be performed to cut down experimental costs and save animal lives. The current reliability of the results is however disputed. Here, a blind exercise in carcinogenicity category assessment is performed using augmented top priority fragment classification. The procedure analyses the applicability domain of the dataset, allocates in clusters the compounds using a leading molecular fragment, and a similarity measure. The exercise is applied to three compound datasets derived from the Lois Gold Carcinogenic Database. The results, showing good agreement with experimental data, are compared with published ones. A final discussion on our viewpoint on the possibilities that the carcinogenicity modelling of chemical compounds offers is presented. PMID:26878128

  5. 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. PMID:25694149

  6. 78 FR 57868 - Nominations to the Report on Carcinogens; Request for Information

    Science.gov (United States)

    2013-09-20

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

  7. Occupational toxicants. Critical data evaluation for MAK values and classification of carcinogens. Vol. 4

    International Nuclear Information System (INIS)

    33 occupational toxicants are reviewed. Data are presented according to toxic effects in animals and man, mode of action, carcinogenicity, genotoxicity, reproductive and development toxicity, and MAK value. (MG)

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

    Science.gov (United States)

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

  9. Mechanisms of Enzyme-Catalyzed Reduction of Two Carcinogenic Nitro-Aromatics, 3-Nitrobenzanthrone and Aristolochic Acid I: Experimental and Theoretical Approaches

    Directory of Open Access Journals (Sweden)

    Marie Stiborová

    2014-06-01

    Full Text Available This review summarizes the results found in studies investigating the enzymatic activation of two genotoxic nitro-aromatics, an environmental pollutant and carcinogen 3-nitrobenzanthrone (3-NBA and a natural plant nephrotoxin and carcinogen aristolochic acid I (AAI, to reactive species forming covalent DNA adducts. Experimental and theoretical approaches determined the reasons why human NAD(PH:quinone oxidoreductase (NQO1 and cytochromes P450 (CYP 1A1 and 1A2 have the potential to reductively activate both nitro-aromatics. The results also contributed to the elucidation of the molecular mechanisms of these reactions. The contribution of conjugation enzymes such as N,O-acetyltransferases (NATs and sulfotransferases (SULTs to the activation of 3-NBA and AAI was also examined. The results indicated differences in the abilities of 3-NBA and AAI metabolites to be further activated by these conjugation enzymes. The formation of DNA adducts generated by both carcinogens during their reductive activation by the NOQ1 and CYP1A1/2 enzymes was investigated with pure enzymes, enzymes present in subcellular cytosolic and microsomal fractions, selective inhibitors, and animal models (including knock-out and humanized animals. For the theoretical approaches, flexible in silico docking methods as well as ab initio calculations were employed. The results summarized in this review demonstrate that a combination of experimental and theoretical approaches is a useful tool to study the enzyme-mediated reaction mechanisms of 3-NBA and AAI reduction.

  10. Green emitting phosphors and blends thereof

    Science.gov (United States)

    Setlur, Anant Achyut; Siclovan, Oltea Puica; Nammalwar, Prasanth Kumar; Sathyanarayan, Ramesh Rao; Porob, Digamber G.; Chandran, Ramachandran Gopi; Heward, William Jordan; Radkov, Emil Vergilov; Briel, Linda Jane Valyou

    2010-12-28

    Phosphor compositions, blends thereof and light emitting devices including white light emitting LED based devices, and backlights, based on such phosphor compositions. The devices include a light source and a phosphor material as described. Also disclosed are phosphor blends including such a phosphor and devices made therefrom.

  11. An Analysis of the Role of Tobacco-Specific Nitrosamines in the Carcinogenicity of Tobacco Smoke

    OpenAIRE

    Brown, Buddy G.; Borschke, August J.; Doolittle, David J.

    2003-01-01

    Cigarette smoke is a complex mixture consisting of more than 4500 chemicals, including several tobacco-specific nitrosamines (TSNA). TSNA typically form in tobacco during the post-harvest period, with some fraction being transferred into mainstream smoke when a cigarette is burned during use. The most studied of the TSNA is 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). NNK has been shown to be carcinogenic in laboratory animals. Studies examining the carcinogenicity of NNK frequently ...

  12. Perturbation of Mitosis through Inhibition of Histone Acetyltransferases: The Key to Ochratoxin A Toxicity and Carcinogenicity?

    OpenAIRE

    Czakai, Kristin; Müller, Katja; Mosesso, Pasquale; Pepe, Gaetano; Schulze, Markus; Gohla, Antje; Patnaik, Debasis; Dekant, Wolfgang; Higgins, Jonathan M.G.; Mally, Angela

    2011-01-01

    Ochratoxin A (OTA) is one of the most potent rodent renal carcinogens studied to date. Although controversial results regarding OTA genotoxicity have been published, it is now widely accepted that OTA is not a mutagenic, DNA-reactive carcinogen. Instead, increasing evidence from both in vivo and in vitro studies suggests that OTA may promote genomic instability and tumorigenesis through interference with cell division. The aim of the present study was to provide further support for disruption...

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

    OpenAIRE

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

    1991-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

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

  15. A review of the genotoxic and carcinogenic effects of aspartame: does it safe or not?

    OpenAIRE

    Yılmaz, Serkan; Uçar, Aslı

    2014-01-01

    The objective of this article is to review genotoxicologic and carcinogenic profile of the artificial sweetener aspartame. Aspartame is a synthetic dipeptide, nearly 180–200 times sweeter than sucrose. It is the most widely used artificial sweetener especially in carbonated and powdered soft drinks, beverages, drugs and hygiene products. There is a discussion ongoing for many years whether aspartame posses genotoxic and carcinogenic risk for humans. This question led to many studies to specif...

  16. Carcinogenic effects of the combined action of 241Am and γ-radiation

    International Nuclear Information System (INIS)

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

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

    OpenAIRE

    MADIA FEDERICA; Worth, Andrew; Corvi, Raffaella

    2016-01-01

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

  18. Carcinogens in Israeli milk: a study in regulatory failure.

    Science.gov (United States)

    Westin, J B

    1993-01-01

    The potential danger to humans of exposure to chemicals shown to be carcinogenic in animals has become increasingly clear in the last 20 years. A gap still exists, however, between the appreciation of the risk by scientists and the willingness of public health authorities to reduce it. Three pesticides, shown repeatedly to produce over a dozen different types of cancer in rats and mice, were discovered in inordinately high concentrations in Israeli milk and dairy products. The three pesticides--alpha-BHC, gamma-BHC (lindane), and DDT--had been shown to be present for ten years or more at mean concentrations up to 100 times those found in U.S. dairy products--with resultant concentrations in breast milk being possibly 800 times greater than those in the United States--yet neither the Ministry of Health nor the Israel Cancer Association made any apparent moves either to warn the public or to rectify the situation. A small consumer organization, Consumer Shield, brought the issue into the open. Through public pressure, court action, and the threat of further legal redress--and despite repeated attacks in the media by the milk producers, the Ministry, and the Cancer Association--Consumer Shield forced the authorities to outlaw the use of alpha-BHC and lindane (DDT no longer being in general use). The ban resulted in a precipitous drop in the concentrations of these substances in Israeli milk. Recent epidemiological and laboratory findings suggest that the dramatic drop in breast cancer mortality rates subsequent to the pesticide ban could be a direct result of that ban. PMID:8375952

  19. Multilayer polymer light emitting devices

    Science.gov (United States)

    Barcikowski, Zachary; Thomas, Adam; Tzolov, Marian

    2013-03-01

    The interplay of device layers and their interfaces is a major area of study in Polymer Light Emitting Devices (PLEDs). Many factors such as the degradation, efficiency, and overall performance depend on how these layers interact with each other. A fundamental understanding of the interfaces of these layers can lend to better performing devices using a multitude of organic polymers deposited in conjunction with each other in several ways. We have studied basic PLED devices in which we vary the emissive layer used, along with final bake temperatures. Devices include a glass substrate with Indium Tin Oxide anode, Aluminum cathode, and Plexcore Hole Injection layer. The active polymer films were spin casted from solution of MEH-PPV and PFO. Single layer and dual layers of several polymers are studied by examining current-voltage characteristics, film densities, impedance measurements, light emission, and efficiency calculations. We have found that not only do dual layers positively alter the performance of the device in the majority of cases, but the solvents in which each layer is originally in when deposited affects the formation of the interface, thereby altering the device mechanisms.

  20. Light emitting device having peripheral emissive region

    Science.gov (United States)

    Forrest, Stephen R

    2013-05-28

    Light emitting devices are provided that include one or more OLEDs disposed only on a peripheral region of the substrate. An OLED may be disposed only on a peripheral region of a substantially transparent substrate and configured to emit light into the substrate. Another surface of the substrate may be roughened or include other features to outcouple light from the substrate. The edges of the substrate may be beveled and/or reflective. The area of the OLED(s) may be relatively small compared to the substrate surface area through which light is emitted from the device. One or more OLEDs also or alternatively may be disposed on an edge of the substrate about perpendicular to the surface of the substrate through which light is emitted, such that they emit light into the substrate. A mode expanding region may be included between each such OLED and the substrate.

  1. 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. PMID:20472697

  2. 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.

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

    Science.gov (United States)

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

    2012-08-01

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

  4. A mechanism-mediated model for carcinogenicity: model content and prediction of the outcome of rodent carcinogenicity bioassays currently being conducted on 25 organic chemicals.

    OpenAIRE

    Purdy, R.

    1996-01-01

    A hierarchical model consisting of quantitative structure-activity relationships based mainly on chemical reactivity was developed to predict the carcinogenicity of organic chemicals to rodents. The model is comprised of quantitative structure-activity relationships, QSARs based on hypothesized mechanisms of action, metabolism, and partitioning. Predictors included octanol/water partition coefficient, molecular size, atomic partial charge, bond angle strain, atomic acceptor delocalizibility, ...

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

    International Nuclear Information System (INIS)

    Application of recently developed gene expression techniques using microarrays in toxicological studies (toxicogenomics) facilitate the interpretation of a toxic compound's mode of action and may also allow the prediction of selected toxic effects based on gene expression changes. In order to test this hypothesis, we investigated whether carcinogens at doses known to induce liver tumors in the 2-year rat bioassay deregulate characteristic sets of genes in a short term in vivo study and whether these deregulated genes represent defined biological pathways. Male Wistar rats were dosed with the four nongenotoxic hepatocarcinogens methapyrilene (MPy, 60 mg/kg/day), diethylstilbestrol (DES, 10 mg/kg/day), Wy-14643 (Wy, 60 mg/kg/day), and piperonylbutoxide (PBO, 1200 mg/kg/day). After 1, 3, 7, and 14 days, the livers were taken for histopathological evaluation and for analysis of the gene expression profiles on Affymetrix RGU34A arrays. The expression profile of the four nongenotoxic carcinogens were compared to the profiles of the four genotoxic carcinogens 2-nitrofluorene (2-NF), dimethylnitrosamine (DMN), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), and aflatoxin B1 (AB1) from a similar study reported previously. By using statistical and clustering tools characteristically deregulated genes were extracted and functionally classified. Distinct cellular pathways were affected by the nongenotoxic carcinogens compared to the genotoxic carcinogens which at least partly correlated with the two-stage model of carcinogenesis. Characteristic to genotoxic carcinogens were a DNA damage response and the activation of proliferative and survival signaling. Nongenotoxic carcinogens showed responses to oxidative DNA or protein damage, as well as cell cycle progression and signs of regeneration. Many of the gene alterations found with the nongenotoxic carcinogens imply compound-specific mechanisms. Although neither a single gene nor a single pathway will be sufficient to

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-08-04

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-01-15

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

  8. Toxicity studies of inhaled beta-emitting radionuclides: status report

    International Nuclear Information System (INIS)

    The influence of total dose and dose rate on the effects of inhaled beta-emitting radionuclides is being studied in laboratory animals. The radionuclides are inhaled either in a relatively soluble form (90SrCl2, 144CeCl3, 91YCl3 or 137CsCl) or in a relatively insoluble form in fused aluminosilicate particles. The organs affected depend on the solubility and chemical characteristics of the radio isotopes. Studies with young adult dogs are complemented with comparable studies in other species (mice, rats and Syrian hamsters), with animals of different ages and with animals repeatedly exposed to 144Ce

  9. Toxicity studies of inhaled beta-emitting radionuclides - status report

    International Nuclear Information System (INIS)

    The influence of total dose and dose rate pattern on the effects of inhaled β-emitting radionuclides is being studied in laboratory animals. The inhaled radionuclides were either in a relatively soluble form (90SrCl2, 144CeCl3, 91YCl3, or 137CsCl), or in a relatively insoluble form in fused aluminosilicate particles. The organs affected depend on the solubility and chemical characteristics of the radionuclides. Studies with young adult dogs are complemented by comparable studies in other species (mice, rats, and Syrian hamsters), with animals of different ages and animals repeatedly exposed to 144Ce. 12 references, 2 figures, 2 tables

  10. A multi-source portable light emitting diode spectrofluorometer.

    Science.gov (United States)

    Obeidat, Safwan; Bai, Baolong; Rayson, Gary D; Anderson, Dean M; Puscheck, Adam D; Landau, Serge Y; Glasser, Tzach

    2008-03-01

    A portable luminescence spectrofluorometer weighing only 1.5 kg that uses multiple light emitting diodes (LEDs) as excitation sources was developed and evaluated. Excitation using a sequence of seven individual broad-band LED emission sources enabled the generation of excitation-emission spectra using a light weight (pistache or Mastic) and Philyria latifolia, and the herbaceous species Medicago sativa (alfalfa), Trifolium spp. (clover), and a feed concentrate. Application of multi-way principal component analysis (MPCA) to the resulting three-dimensional data sets enabled discernment among these various diet constituents. PMID:18339242

  11. Clear Evidence of Carcinogenic Activity by a Whole-Leaf Extract of Aloe barbadensis Miller (Aloe vera) in F344/N Rats

    OpenAIRE

    Boudreau, Mary D.; Mellick, Paul W.; Olson, Greg R.; Felton, Robert P.; Thorn, Brett T.; Beland, Frederick A.

    2012-01-01

    Aloe barbadensis Miller (Aloe vera) is an herbal remedy promoted to treat a variety of illnesses; however, only limited data are available on the safety of this dietary supplement. Drinking water exposure of F344/N rats and B6C3F1 mice to an Aloe vera whole-leaf extract (1, 2, and 3%) for 13 weeks resulted in goblet cell hyperplasia of the large intestine in both species. Based upon this observation, 2-year drinking water studies were conducted to assess the carcinogenic potential of an Aloe ...

  12. Mitochondrial emitted electromagnetic signals mediate retrograde signaling.

    Science.gov (United States)

    Bagkos, Georgios; Koufopoulos, Kostas; Piperi, Christina

    2015-12-01

    Recent evidence shows that mitochondria regulate nuclear transcriptional activity both in normal and cell stress conditions, known as retrograde signaling. Under normal mitochondrial function, retrograde signaling is associated with mitochondrial biogenesis, normal cell phenotype and metabolic profile. In contrast, mitochondrial dysfunction leads to abnormal (oncogenic) cell phenotype and altered bio-energetic profile (nucleus reprogramming). Despite intense research efforts, a concrete mechanism through which mitochondria determine the group of genes expressed by the nucleus is still missing. The present paper proposes a novel hypothesis regarding retrograde signaling. More specifically, it reveals the mitochondrial membrane potential (MMP) and the accompanied strong electromagnetic field (EF) as key regulatory factors of nuclear activity. Mitochondrial emitted EFs extend in long distance and affect the function of nuclear membrane receptors. Depending on their frequencies, EFs can directly activate or deactivate different groups of nuclear receptors and so determine nuclear gene expression. One of the key features of the above hypothesis is that nuclear membrane receptors, besides their own endogenous or chemical ligands (hormones, lipids, etc.), can also be activated by electromagnetic signals. Moreover, normal MMP values (about -140 mV) are associated with the production of high ATP quantities and small levels of reactive oxygen species (ROS) while the hyperpolarization observed in all cancer cell types leads to a dramatic fall in ATP production and an analogous increase in ROS. The diminished ATP and increased ROS production negatively affect the function of all cellular systems including nucleus. Restoration of mitochondrial function, which is characterized by the fluctuation of MMP and EF values within a certain (normal) range, is proposed as a necessary condition for normal nuclear function and cancer therapy. PMID:26474928

  13. Wheat Under LED's (Light Emitting Diodes)

    Science.gov (United States)

    2004-01-01

    Astroculture is a suite of technologies used to produce and maintain a closed controlled environment for plant growth. The two most recent missions supported growth of potato, dwarf wheat, and mustard plants, and provided scientists with the first opportunity to conduct true plant research in space. Light emitting diodes have particular usefulness for plant growth lighting because they emit a much smaller amount of radiant heat than do conventional lighting sources and because they have potential of directing a higher percentage of the emitted light onto plants surfaces. Furthermore, the high output LED's have emissions in the 600-700 nm waveband, which is of highest efficiency for photosynthesis by plants.

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

    International Nuclear Information System (INIS)

    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 [LD50]), lowest-observed-adverse-effect-level (LOAEL) and maximum tolerated dose (MTD). The purpose of this study was to investigate the correlation between tumor dose (TD50) 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 TD50 and estimated/experimental predictor variables to predict the carcinogenic potency of new chemicals. Rat TD50s 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 TD50 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

  15. Comparative genomics and proteomics of Helicobacter mustelae, an ulcerogenic and carcinogenic gastric pathogen

    LENUS (Irish Health Repository)

    O'Toole, Paul W

    2010-03-10

    Abstract Background Helicobacter mustelae causes gastritis, ulcers and gastric cancer in ferrets and other mustelids. H. mustelae remains the only helicobacter other than H. pylori that causes gastric ulceration and cancer in its natural host. To improve understanding of H. mustelae pathogenesis, and the ulcerogenic and carcinogenic potential of helicobacters in general, we sequenced the H. mustelae genome, and identified 425 expressed proteins in the envelope and cytosolic proteome. Results The H. mustelae genome lacks orthologs of major H. pylori virulence factors including CagA, VacA, BabA, SabA and OipA. However, it encodes ten autotransporter surface proteins, seven of which were detected in the expressed proteome, and which, except for the Hsr protein, are of unknown function. There are 26 putative outer membrane proteins in H. mustelae, some of which are most similar to the Hof proteins of H. pylori. Although homologs of putative virulence determinants of H. pylori (NapA, plasminogen adhesin, collagenase) and Campylobacter jejuni (CiaB, Peb4a) are present in the H. mustelae genome, it also includes a distinct complement of virulence-related genes including a haemagglutinin\\/haemolysin protein, and a glycosyl transferase for producing blood group A\\/B on its lipopolysaccharide. The most highly expressed 264 proteins in the cytosolic proteome included many corresponding proteins from H. pylori, but the rank profile in H. mustelae was distinctive. Of 27 genes shown to be essential for H. pylori colonization of the gerbil, all but three had orthologs in H. mustelae, identifying a shared set of core proteins for gastric persistence. Conclusions The determination of the genome sequence and expressed proteome of the ulcerogenic species H mustelae provides a comparative model for H. pylori to investigate bacterial gastric carcinogenesis in mammals, and to suggest ways whereby cag minus H. pylori strains might cause ulceration and cancer. The genome sequence was

  16. Swedish review strengthens grounds for concluding that radiation from cellular and cordless phones is a probable human carcinogen.

    Science.gov (United States)

    Davis, Devra Lee; Kesari, Santosh; Soskolne, Colin L; Miller, Anthony B; Stein, Yael

    2013-04-01

    With 5.9 billion reported users, mobile phones constitute a new, ubiquitous and rapidly growing exposure worldwide. Mobile phones are two-way microwave radios that also emit low levels of electromagnetic radiation. Inconsistent results have been published on potential risks of brain tumors tied with mobile phone use as a result of important methodological differences in study design and statistical power. Some studies have examined mobile phone users for periods of time that are too short to detect an increased risk of brain cancer, while others have misclassified exposures by placing those with exposures to microwave radiation from cordless phones in the control group, or failing to attribute such exposures in the cases. In 2011, the World Health Organization, International Agency for Research on Cancer (IARC) advised that electromagnetic radiation from mobile phone and other wireless devices constitutes a "possible human carcinogen," 2B. Recent analyses not considered in the IARC review that take into account these methodological shortcomings from a number of authors find that brain tumor risk is significantly elevated for those who have used mobile phones for at least a decade. Studies carried out in Sweden indicate that those who begin using either cordless or mobile phones regularly before age 20 have greater than a fourfold increased risk of ipsilateral glioma. Given that treatment for a single case of brain cancer can cost between $100,000 for radiation therapy alone and up to $1 million depending on drug costs, resources to address this illness are already in short supply and not universally available in either developing or developed countries. Significant additional shortages in oncology services are expected at the current growth of cancer. No other environmental carcinogen has produced evidence of an increased risk in just one decade. Empirical data have shown a difference in the dielectric properties of tissues as a function of age, mostly due to the

  17. Why the entropy of spacetime is independent of species of particles -- the species problem

    CERN Document Server

    Chen, Yu-Zhu; Dai, Wu-Sheng

    2016-01-01

    The Hawking radiation emits all species of particles, but the Bekenstein-Hawking entropy is independent of the number of the species of particles. This is the so-called species problem -- a puzzling problem for a long time. In this paper, we suggest a solution to this problem.

  18. Toxicity and carcinogenicity studies of Caramel Colour IV in F344 rats and B6C3F1 mice.

    Science.gov (United States)

    MacKenzie, K M; Boysen, B G; Field, W E; Petsel, S R; Chappel, C I; Emerson, J L; Stanley, J

    1992-05-01

    Caramel Colour IV, a type of caramel colour used in the manufacture of cola soft drinks, was evaluated for subchronic and chronic toxicity in rats, and carcinogenicity in Fischer-344 (F344) rats and B6C3F1 mice. In each of the studies, Caramel Colour IV was mixed with demineralized water and the solutions given to the animals ad lib. in the drinking fluid. The concentrations of Caramel Colour IV in the drinking fluid were adjusted periodically to achieve the desired caramel colour intake per kg body weight. In the range-finding studies, groups of 30 rats/sex were given Caramel Colour IV at levels of 0, 15, 20, 25 or 30 g/kg for 13 wk, and groups of 10 male rats were given levels of 0, 2.5, 5, 10 or 15 g/kg for 6 wk followed, for some dose groups, by a 2-wk withdrawal period, and then re-initiation of dosing for another 2 wk. In the rat chronic toxicity study, levels of Caramel Colour IV of 0, 2.5, 5, 7.5 or 10 g/kg were given to groups of 25 rats/sex for 12 months. The test groups in the rat and mouse carcinogenicity studies were composed of 50 animals/sex and each species was given the caramel colour at levels of 0, 0, 2.5, 5 or 10 g/kg for 24 months. In each of the studies, treated animals tended to have dose-related lower water consumption than controls. This was attributed to poor palatability of the drinking fluid, and was generally associated with decreased food consumption and body weights. Rats given caramel colour often had soft or liquid malodorous faeces although there were no treatment-related ante-mortem observations in mice. Blood biochemical changes in the rat (i.e. reduced blood urea nitrogen, alkaline phosphatase and total serum protein) appeared to be related to dietary influences and were not considered toxicologically significant. There were no treatment-related alterations in haematological variables or treatment-related differences in survival or in the incidence of benign or malignant tumours among treated and control groups and no

  19. E-Cigarettes Emit Toxic Vapors

    Science.gov (United States)

    ... page: https://medlineplus.gov/news/fullstory_160107.html E-Cigarettes Emit Toxic Vapors: Study Levels depend on ... findings could be important to both makers of e-cigarettes and regulators who want to reduce the ...

  20. Organic emitters: Light-emitting fabrics

    Science.gov (United States)

    Ortí, Enrique; Bolink, Henk J.

    2015-04-01

    Light-emitting fibres that suit integration with textiles are prepared by dip-coating a steel wire with an electroluminescent material and then cleverly wrapping the structure with a carbon nanotube sheet that functions as a transparent electrode.

  1. Blue emitting organic semiconductors under high pressure

    DEFF Research Database (Denmark)

    Knaapila, Matti; Guha, Suchismita

    2016-01-01

    This review describes essential optical and emerging structural experiments that use high GPa range hydrostatic pressure to probe physical phenomena in blue-emitting organic semiconductors including π-conjugated polyfluorene and related compounds. The work emphasizes molecular structure and...

  2. Radiation Emitting Product Corrective Actions and Recalls

    Data.gov (United States)

    U.S. Department of Health & Human Services — This database provides descriptions of radiation-emitting products that have been recalled under an approved corrective action plan to remove defective and...

  3. Radiation-emitting Electronic Product Codes

    Data.gov (United States)

    U.S. Department of Health & Human Services — This database contains product names and associated information developed by the Center for all products, both medical and non-medical, which emit radiation. It...

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

    International Nuclear Information System (INIS)

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

  5. Opportunities for an alternative integrating testing strategy for carcinogen hazard assessment?

    Science.gov (United States)

    Doktorova, Tatyana Y; Pauwels, Marleen; Vinken, Mathieu; Vanhaecke, Tamara; Rogiers, Vera

    2012-02-01

    The 2-year rodent carcinogenicity bioassay evolved more than 40 years ago, and although it is complex, long lasting, expensive, and animal consuming, it is still the only generally accepted test for assessing the carcinogenicity of chemicals. Over time, different alternative approaches have been developed with the final goal to replace the bioassay. Unfortunately, at present, none of these strategies alone provides sufficient assurance of accurate prediction. In this review paper, we discuss the major advantages and pitfalls of the existing alternative methodologies to the carcinogenicity bioassay. Finally, based on the available scientific data in the public domain, we propose what we would like to call a "feasible integrated testing strategy" which incorporates some promising alternatives, providing at the same time information on the mechanism of action and the toxic nature of the compounds tested. It is, however, clear that the adoption of whatever "new" testing scheme should be considered with caution and its effectiveness should be experimentally demonstrated in advance by addressing a reasonable number of chemical carcinogens and non-carcinogens from a variety of structural and functional classes. PMID:22141324

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  8. Is peroxisome proliferation an obligatory precursor step in the carcinogenicity of di(2-ethylhexyl)phthalate (DEHP)?

    OpenAIRE

    Melnick, R L

    2001-01-01

    Di(2-ethylhexyl)phthalate (DEHP), a peroxisome proliferator, has been listed by the International Agency for Research on Cancer (IARC) and by the National Toxicology Program as a possible or reasonably anticipated human carcinogen because it induces dose-related increases in liver tumors in both sexes of rats and mice. Recently, the suggestion has been advanced that DEHP should be considered unlikely to be a human carcinogen because it is claimed that the carcinogenic effects of this agent in...

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

    OpenAIRE

    Leadon, S A

    1987-01-01

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

  10. Inhalation and dermal exposure to atmospheric polycyclic aromatic hydrocarbons and associated carcinogenic risks in a relatively small city.

    Science.gov (United States)

    Gungormus, Elif; Tuncel, Semra; Hakan Tecer, Lokman; Sofuoglu, Sait C

    2014-10-01

    The aim of this study was to conduct a carcinogenic risk assessment for exposure to polycyclic aromatic hydrocarbons (PAHs) via routes of inhalation and dermal contact. Concentrations of 19 PAH species were determined during a heating period at a site in the city of Balikesir, Turkey. Two questionnaires were administered to a sample of inhabitants to determine time-activity budgets and demographic information. The assessment was conducted for each participant and Balikesir population by deterministic and probabilistic approaches, respectively. Monte Carlo simulation was implemented to determine the population exposure-risk probability distributions. The estimates were based on benzo[a]pyrene equivalent (BaPeq) total PAH concentrations calculated using toxic equivalency factors. The mean and median BaPeq concentrations of gaseous and particulate phases were 3.25 and 1.34, and 38.5 and 34.0ng/m(3), respectively. Carcinogenic risk for inhalation exposure route was estimated by using two different slope factor values (3.9 and 304.5(mg/kg-day)(-1)), recommended by two different organizations, resulting in two (order(s) of magnitude apart) population risk ranges: 1.32×10(-7)-2.23×10(-4), and 1.61×10(-5)-7.95×10(-3), respectively. The population risks associated with dermal exposure were lower compared to those of inhalation, ranging from 6.58×10(-9) to 2.57×10(-6). The proportion of the population with risks higher than the general acceptable level (1.0×10(-6)) was estimated as >99 percent, for inhalation, and as 28 percent for dermal exposure route. PMID:25046852

  11. Modulation of carcinogen bioavailability by immunisation with benzo[a]pyrene-conjugate vaccines.

    Science.gov (United States)

    Grova, Nathalie; Prodhomme, Emmanuel J F; Schellenberger, Mario T; Farinelle, Sophie; Muller, Claude P

    2009-06-24

    Benzo[a]pyrene (B[a]P) conjugate vaccines based on ovalbumin, tetanus toxoid and diphtheria toxoid (DT) as carrier proteins were developed to investigate the effect of specific antibodies on the bioavailability of this ubiquitous carcinogen and its metabolites. After metabolic activation of this prototype carcinogen, B[a]P forms DNA adducts which initiate chemical carcinogenesis. B[a]P-DT conjugate induced the most robust immune response. The antibodies reacted not only with B[a]P but also with the proximate carcinogen 7,8-diol-B[a]P. Antibodies modulated the bioavailability of B[a]P and its metabolic activation in a dose-dependent manner by sequestration in the blood. Our results showed that this immune prophylactic strategy influences the pharmacokinetic of B[a]P and further studies to investigate their effects on chemical carcinogenesis are warranted. PMID:19406187

  12. A review of the genotoxic and carcinogenic effects of aspartame: does it safe or not?

    Science.gov (United States)

    Yılmaz, Serkan; Uçar, Aslı

    2014-12-01

    The objective of this article is to review genotoxicologic and carcinogenic profile of the artificial sweetener aspartame. Aspartame is a synthetic dipeptide, nearly 180-200 times sweeter than sucrose. It is the most widely used artificial sweetener especially in carbonated and powdered soft drinks, beverages, drugs and hygiene products. There is a discussion ongoing for many years whether aspartame posses genotoxic and carcinogenic risk for humans. This question led to many studies to specify the adverse effects of aspartame. Therefore, we aimed to review the oldest to latest works published in major indices to gather information within this article. With respect to published data, genotoxicity and carcinogenicity of aspartame is still confusing. So, consumers should be aware of the potential side effects of aspartame before they consume it. PMID:24510317

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

    International Nuclear Information System (INIS)

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

  14. Chemical and molecular basis of the carcinogenicity of Aristolochia plants

    OpenAIRE

    Schmeiser, Heinz H.; Stiborova, Marie; Arlt, Volker M.

    2009-01-01

    The herbal drug aristolochic acid (AA), which is derived from the Aristolochia species, has been associated with the development of a novel nephropathy, designated as aristolochic acid nephropathy (AAN), and with human urothelial cancer. The major components of the plant extract AA are nitrophenanthrene carboxylic acids, which, after metabolic activation, are genotoxic mutagens. The major activation pathway of AA involves reduction of the nitro group, primarily catalyzed by NAD(P) H: quinone ...

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

    OpenAIRE

    Premi, Sanjay; Brash, Douglas E.

    2015-01-01

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

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

    Science.gov (United States)

    Premi, Sanjay; Brash, Douglas E

    2016-01-01

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

  17. Carcinogenicity of consumption of red and processed meat: What about environmental contaminants?

    Science.gov (United States)

    Domingo, José L; Nadal, Martí

    2016-02-01

    In October 26, 2015, the International Agency for Research on Cancer (IARC) issued a press release informing of the recent evaluation of the carcinogenicity of red and processed meat consumption. The consumption of red meat and processed meat was classified as "probably carcinogenic to humans", and as "carcinogenic to humans", respectively. The substances responsible of this potential carcinogenicity would be generated during meat processing, such as curing and smoking, or when meat is heated at high temperatures (N-nitroso-compounds, polycyclic aromatic hydrocarbons and heterocyclic aromatic amines). However, in its assessments, the IARC did not make any reference to the role that may pose some carcinogenic environmental pollutants, which are already present in raw or unprocessed meat. The potential role of a number of environmental chemical contaminants (toxic trace elements, polycyclic aromatic hydrocarbons, polychlorinated dibenzo-p-dioxins and dibenzofurans, polychlorinated biphenyls, polybrominated diphenyl ethers, polychlorinated diphenyl ethers, polychlorinated naphthalenes and perfluoroalkyl substances) on the carcinogenicity of consumption of meat and meat products is discussed in this paper. A case-study, Catalonia (Spain), is specifically assessed, while the influence of cooking on the concentrations of environmental pollutants is also reviewed. It is concluded that although certain cooking processes could modify the levels of chemical contaminants in food, the influence of cooking on the pollutant concentrations depends not only on the particular cooking process, but even more on their original contents in each specific food item. As most of these environmental pollutants are organic, cooking procedures that release or remove fat from the meat should tend to reduce the total concentrations of these contaminants in the cooked meat. PMID:26656511

  18. 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

  19. 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.)

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

    Science.gov (United States)

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

    1975-08-15

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

  1. White emission from nano-structured top-emitting organic light-emitting diodes based on a blue emitting layer

    International Nuclear Information System (INIS)

    We demonstrated that white emission can be obtained from nano-structured top-emitting organic light-emitting diodes (TEOLEDs) based on a blue emitting layer (EML). The nano-structured TEOLEDs were fabricated on nano-patterned substrates, in which both optical micro-cavity and scattering effects occur simultaneously. Due to the combination of these two effects, the electroluminescence spectra of the nano-structured device with a blue EML exhibited not only blue but also yellow colours, which corresponded to the intrinsic emission of the EML and the resonant emission of the micro-cavity effect. Consequently, it was possible to produce white emission from nano-structured TEOLEDs without employing a multimode micro-cavity. The intrinsic emission wavelength can be varied by altering the dopant used for the EML. Furthermore, the emissive characteristics turned out to be strongly dependent on the nano-pattern sizes of the nano-structured devices. (paper)

  2. Distinct mechanisms of oxidative DNA damage induced by carcinogenic nickel subsulfide and nickel oxides.

    OpenAIRE

    Kawanishi, Shosuke; Oikawa, Shinji; Inoue, Sumiko; Nishino, Kohsuke

    2002-01-01

    The U.S. National Toxicology Program has shown clear evidence of carcinogenicity of nickel subsulfide (Ni(3)S(2)) and some evidence of carcinogenicity of NiO (green) in rats. In the present study, DNA damage in cultured cells and in lungs of rats induced by nickel compounds was investigated to clarify the mechanism of nickel carcinogenesis. In cultured HeLa cells, Ni(3)S(2) induced a significant increase in 8-hydroxydeoxyguanosine (8-OH-dG) formation, whereas NiO (black), NiO (green), and NiS...

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

    DEFF Research Database (Denmark)

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

    2013-01-01

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

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

    International Nuclear Information System (INIS)

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

  5. The Cigarette Smoke Carcinogen Benzo[a]pyrene Enhances Human Papillomavirus Synthesis▿

    OpenAIRE

    Alam, Samina; Conway, Michael J; Chen, Horng-Shen; Meyers, Craig

    2007-01-01

    Epidemiological studies suggest that cigarette smoke carcinogens are cofactors which synergize with human papillomavirus (HPV) to increase the risk of cervical cancer progression. Benzo[a]pyrene (BaP), a major carcinogen in cigarette smoke, is detected in the cervical mucus and may interact with HPV. Exposure of cervical cells to high concentrations of BaP resulted in a 10-fold increase in HPV type 31 (HPV31) viral titers, whereas treatment with low concentrations of BaP resulted in an increa...

  6. Tobacco Carcinogen NNK Transporter MRP2 Regulates CFTR Function in Lung Epithelia: Implications for Lung Cancer

    OpenAIRE

    Li, Chunying; Schuetz, John D.; Naren, Anjaparavanda P.

    2010-01-01

    Lung cancer is the leading cause of cancer death in the United States. About 85% of all lung cancers are linked to tobacco smoke, in which more than 50 lung carcinogens have been identified and one of the most abundant is 4-(methylnitrosamino)-1-(3-pyridyl)- 1-butanone (NNK). The human lung epithelium constitutes the first line of defense against tobacco specific carcinogens, in which apically-localized receptors, transporters, and ion channels in the airway may play a critical role in this n...

  7. Effects of doping dyes on the electroluminescent characteristics of multilayer organic light-emitting diodes

    Science.gov (United States)

    Suzuki, Hiroyuki; Hoshino, Satoshi

    1996-06-01

    We report the effects of dyes doped in the emitting layer on the electroluminescent characteristics of multilayer organic light-emitting diodes (LEDs) using a polysilane polymer, poly(methylphenylsilane) (PMPS), as the hole transporting material. We formed the emitting layer by dispersing in poly(styrene) (PS), one of four dyes whose fluorescence ranged from blue to orange. Two- or three-layer LEDs were prepared by combining PMPS and dye doped PS layers with the indium tin oxide and aluminum used for the hole and electron injecting electrodes, respectively. The three-layer LEDs had an additional vacuum-deposited tris-(8-hydroxyquinoline) aluminum layer. The electroluminescent (EL) characteristics of these multilayer organic LEDs, such as the current-voltage-EL intensity curve, the relative EL efficiency, and the EL emitting species, exhibit a marked dependence on the emitting dye. The observed dependence can be described consistently in terms of the dependence of the charge carrier trapping efficiency on the emitting dyes.

  8. Side-emitting fiber optic position sensor

    Science.gov (United States)

    Weiss, Jonathan D.

    2008-02-12

    A side-emitting fiber optic position sensor and method of determining an unknown position of an object by using the sensor. In one embodiment, a concentrated beam of light source illuminates the side of a side-emitting fiber optic at an unknown axial position along the fiber's length. Some of this side-illuminated light is in-scattered into the fiber and captured. As the captured light is guided down the fiber, its intensity decreases due to loss from side-emission away from the fiber and from bulk absorption within the fiber. By measuring the intensity of light emitted from one (or both) ends of the fiber with a photodetector(s), the axial position of the light source is determined by comparing the photodetector's signal to a calibrated response curve, look-up table, or by using a mathematical model. Alternatively, the side-emitting fiber is illuminated at one end, while a photodetector measures the intensity of light emitted from the side of the fiber, at an unknown position. As the photodetector moves further away from the illuminated end, the detector's signal strength decreases due to loss from side-emission and/or bulk absorption. As before, the detector's signal is correlated to a unique position along the fiber.

  9. Radiation emitted from rocket plumes

    Energy Technology Data Exchange (ETDEWEB)

    Deimling, L.; Liehmann, W.; Eisenreich, N.; Weindel, M.; Eckl, W. [Fraunhofer-Institut fuer Chemische Technologie (ICT), Pfinztal-Berghausen (Germany)

    1997-07-01

    The signature of rocket plumes can be used for detection, identification and guidance of rockets. The objective was to investigate the signature of various types of solid rocket propellants by application of spectroscopic methods. The emission and transmission characteristics of plumes were studied experimentally, the results were analyzed based on molecular bands and continuum radiation. The model formulations include a nitramine propellant, a double-base propellant and a composite propellant. Applied were rapid-scanning filter wheel spectormeters for the wavelength region from 1.2 {mu}m to 14 {mu}m with a time resolution of 50 spectra/s and a wavelengths resolution of 1% of actual wavelength. The UV/VIS wavelengths region was recorded by an OMA system with wavelength resolution of 0.1 nm and 1 nm and time resolution of 10 spectra/s. Molecular bands of water and carbon dioxide dominate in the near infrared and infrared. Depending on composition, continuous radiation indicates particles in the rocket exhaust. A code was developed to calculate molecular bands and continuous rdiation using temperature and species distributions found by thermodynamic estimation to obtain the radiance of the plume. Comparison with experimental data delivered plume temperatures. (orig.) [Deutsch] Die Signatur von Raketenabgasstrahlen kann genutzt werden zur Detektion, Identifikation und Lenkung. Ziel der vorgestellten Arbeit war die Untersuchung der Signaturen unterschiedlicher Raketenfesttreibstoffe mittels spektroskopischer Verfahren. Die Emissions- und Transmissionscharakteristik wurde experimentell untersucht und die erhaltenen Daten auf der Basis kontinuierlicher und molekularer Strahlung analysiert. Die Modellformulierungen umfassten einen Nitramin - Treibstoff, eine Double-base - Formulierung und einen Composittreibstoff. Angewendet wurden Filterradspektrometer fuer den infraroten Spektralbereich und ein konventionelles Gitterspektrometer im Ultravioletten und Sichtbaren. Die

  10. Nitroaromatic compounds: Environmental toxicity, carcinogenicity, mutagenicity, therapy and mechanism.

    Science.gov (United States)

    Kovacic, Peter; Somanathan, Ratnasamy

    2014-08-01

    Vehicle pollution is an increasing problem in the industrial world. Aromatic nitro compounds comprise a significant portion of the threat. In this review, the class includes nitro derivatives of benzene, biphenyls, naphthalenes, benzanthrone and polycyclic aromatic hydrocarbons, plus nitroheteroaromatic compounds. The numerous toxic manifestations are discussed. An appreciable number of drugs incorporate the nitroaromatic structure. The mechanistic aspects of both toxicity and therapy are addressed in the context of a unifying mechanism involving electron transfer, reactive oxygen species, oxidative stress and antioxidants. PMID:24532466

  11. Improved Quantum Efficiency of Organic Light Emitting Diodes with Gradiently Doped Double Emitting Zone

    Institute of Scientific and Technical Information of China (English)

    高文宝; 姜文龙; 孙家鑫; 冯晶; 侯晶莹; 刘式墉

    2003-01-01

    We investigate electroluminescent characteristics of gradiently doped organic light-emitting diodes, which were gradiently doped in both the hole and the electron-transporting layer to form a double emitting zone. The device structure was ITO/(15nm) CuPc/(60nm)NPB:rubrene/(30nm)Alqs:rubrene/(20nm)Alqs/(0.5nm)LiF/Al. We observed that charge carriers were well trapped by the dopant molecules and the main emitting zone was localized at the NPB:rubrene side close to the interface of NPB:rubrene/Alqs:rubrene. The quantum efficiency (cd/A) was enhanced to 5.89 cd/A at 6 V. We attributed this improvement to the charge carriers trapping and the emitting of the double emitting zone.

  12. 75 FR 79320 - Animal Drugs, Feeds, and Related Products; Regulation of Carcinogenic Compounds in Food-Producing...

    Science.gov (United States)

    2010-12-20

    ... human diet that represents no significant increase in the risk of cancer to people. The concentration... defined, adequately addresses concentrations of residues of carcinogenic concern in the total human diet... secondarily as corresponding to the concentration of residue of carcinogenic concern in the total human...

  13. Calorimetric measurement of strong γ emitting sources

    International Nuclear Information System (INIS)

    This publication gives the principle and a description of an adiabatic calorimeter for measuring the real activity of strong gamma-emitting sources by absorbing the emitted energy in a mass of copper. Because of the difficulty of evaluating the amount self- absorption, we have built a calorimeter for measuring the self- absorption, and a description of it is given.The results of these three measurements are fairly satisfactory. The calibration and the actual measurements obtained are given with a few corrections made necessary by the design of the apparatus. The correlation of the various results is discussed. (author)

  14. Unifying mechanism for metals in toxicity, carcinogenicity and therapeutic action: integrated approach involving electron transfer, oxidative stress, antioxidants, cell signaling and receptors.

    Science.gov (United States)

    Kovacic, Peter; Somanathan, Ratnasamy

    2010-04-01

    This comprehensive review of biometals involves the unifying theme of electron transfer, reactive oxygen species, and oxidative stress (OS) applied to toxicity, carcinogenicity, and therapeutic action. The beneficial effect of antioxidants supports the participation of OS. The metals involved are mainly in the heavier category. An important aspect is the favorable reduction potential exhibited by the bioactive materials that permits redox cycling in vivo with the generation of oxy radicals. The basic mechanistic theme is applicable to other electron transfer (ET) functionalities. Appreciable evidence indicates the participation of cell signaling in various ways. Also, a simplifying framework is provided based on radical species and electrochemistry (ET and molecular electrostatic potential). This review also discusses receptor participation with focus on binding to proteins. Resultant physiological effects are summarized. The overview provides an integrated approach to metal bioactivation. PMID:20144140

  15. Comparison of carcinogen, carbon monoxide, and ultrafine particle emissions from narghile waterpipe and cigarette smoking: Sidestream smoke measurements and assessment of second-hand smoke emission factors

    Science.gov (United States)

    Daher, Nancy; Saleh, Rawad; Jaroudi, Ezzat; Sheheitli, Hiba; Badr, Thérèse; Sepetdjian, Elizabeth; Al Rashidi, Mariam; Saliba, Najat; Shihadeh, Alan

    2010-01-01

    The lack of scientific evidence on the constituents, properties, and health effects of second-hand waterpipe smoke has fueled controversy over whether public smoking bans should include the waterpipe. The purpose of this study was to investigate and compare emissions of ultrafine particles (UFP, hookah) waterpipes. These smoke constituents are associated with a variety of cancers, and heart and pulmonary diseases, and span the volatility range found in tobacco smoke. Sidestream cigarette and waterpipe smoke was captured and aged in a 1 m 3 Teflon-coated chamber operating at 1.5 air changes per hour (ACH). The chamber was characterized for particle mass and number surface deposition rates. UFP and CO concentrations were measured online using a fast particle spectrometer (TSI 3090 Engine Exhaust Particle Sizer), and an indoor air quality monitor. Particulate PAH and gaseous volatile aldehydes were captured on glass fiber filters and DNPH-coated SPE cartridges, respectively, and analyzed off-line using GC-MS and HPLC-MS. PAH compounds quantified were the 5- and 6-ring compounds of the EPA priority list. Measured aldehydes consisted of formaldehyde, acetaldehyde, acrolein, methacrolein, and propionaldehyde. We found that a single waterpipe use session emits in the sidestream smoke approximately four times the carcinogenic PAH, four times the volatile aldehydes, and 30 times the CO of a single cigarette. Accounting for exhaled mainstream smoke, and given a habitual smoker smoking rate of 2 cigarettes per hour, during a typical one-hour waterpipe use session a waterpipe smoker likely generates ambient carcinogens and toxicants equivalent to 2-10 cigarette smokers, depending on the compound in question. There is therefore good reason to include waterpipe tobacco smoking in public smoking bans.

  16. Comparison of carcinogen, carbon monoxide, and ultrafine particle emissions from narghile waterpipe and cigarette smoking: Sidestream smoke measurements and assessment of second-hand smoke emission factors

    Science.gov (United States)

    Daher, Nancy; Saleh, Rawad; Jaroudi, Ezzat; Sheheitli, Hiba; Badr, Thérèse; Sepetdjian, Elizabeth; Al Rashidi, Mariam; Saliba, Najat; Shihadeh, Alan

    2010-01-01

    The lack of scientific evidence on the constituents, properties, and health effects of second-hand waterpipe smoke has fueled controversy over whether public smoking bans should include the waterpipe. The purpose of this study was to investigate and compare emissions of ultrafine particles (UFP, range found in tobacco smoke. Sidestream cigarette and waterpipe smoke was captured and aged in a 1 m 3 Teflon-coated chamber operating at 1.5 air changes per hour (ACH). The chamber was characterized for particle mass and number surface deposition rates. UFP and CO concentrations were measured online using a fast particle spectrometer (TSI 3090 Engine Exhaust Particle Sizer), and an indoor air quality monitor. Particulate PAH and gaseous volatile aldehydes were captured on glass fiber filters and DNPH-coated SPE cartridges, respectively, and analyzed off-line using GC-MS and HPLC-MS. PAH compounds quantified were the 5- and 6-ring compounds of the EPA priority list. Measured aldehydes consisted of formaldehyde, acetaldehyde, acrolein, methacrolein, and propionaldehyde. We found that a single waterpipe use session emits in the sidestream smoke approximately four times the carcinogenic PAH, four times the volatile aldehydes, and 30 times the CO of a single cigarette. Accounting for exhaled mainstream smoke, and given a habitual smoker smoking rate of 2 cigarettes per hour, during a typical one-hour waterpipe use session a waterpipe smoker likely generates ambient carcinogens and toxicants equivalent to 2-10 cigarette smokers, depending on the compound in question. There is therefore good reason to include waterpipe tobacco smoking in public smoking bans.

  17. Ochratoxin A: An overview on toxicity and carcinogenicity in animals and humans.

    Science.gov (United States)

    Pfohl-Leszkowicz, Annie; Manderville, Richard A

    2007-01-01

    Ochratoxin A (OTA) is a ubiquitous mycotoxin produced by fungi of improperly stored food products. OTA is nephrotoxic and is suspected of being the main etiological agent responsible for human Balkan endemic nephropathy (BEN) and associated urinary tract tumours. Striking similarities between OTA-induced porcine nephropathy in pigs and BEN in humans are observed. International Agency for Research on Cancer (IARC) has classified OTA as a possible human carcinogen (group 2B). Currently, the mode of carcinogenic action by OTA is unknown. OTA is genotoxic following oxidative metabolism. This activity is thought to play a central role in OTA-mediated carcinogenesis and may be divided into direct (covalent DNA adduction) and indirect (oxidative DNA damage) mechanisms of action. Evidence for a direct mode of genotoxicity has been derived from the sensitive 32P-postlabelling assay. OTA facilitates guanine-specific DNA adducts in vitro and in rat and pig kidney orally dosed, one adduct comigrates with a synthetic carbon (C)-bonded C8-dG OTA adduct standard. In this paper, our current understanding of OTA toxicity and carcinogenicity are reviewed. The available evidence suggests that OTA is a genotoxic carcinogen by induction of oxidative DNA lesions coupled with direct DNA adducts via quinone formation. This mechanism of action should be used to establish acceptable intake levels of OTA from human food sources. PMID:17195275

  18. Environmental exposure to carcinogenic polycyclic aromatic hydrocarbons – the interpretation of cytogenetic analysis by FISH

    Czech Academy of Sciences Publication Activity Database

    Šrám, Radim; Beskid, Olena; Rössnerová, Andrea; Rössner st., Pavel; Lněničková, Zdena; Milcová, Alena; Solansky, I.; Binková, Blanka

    2007-01-01

    Roč. 172, - (2007), s. 12-20. ISSN 0378-4274 R&D Projects: GA MŽP SL/5/160/05 Institutional research plan: CEZ:AV0Z50390512 Keywords : environmental pollution * carcinogenic polycyclic aromatic hydrocarbons * cytogenetic analysis Subject RIV: DN - Health Impact of the Environment Quality Impact factor: 2.826, year: 2007

  19. 29 CFR 1990.131 - Priority lists for regulating potential occupational carcinogens.

    Science.gov (United States)

    2010-07-01

    ... review or be the basis for any legal action. The Secretary may regulate a potential occupational... 29 Labor 9 2010-07-01 2010-07-01 false Priority lists for regulating potential occupational... POTENTIAL OCCUPATIONAL CARCINOGENS Priority Setting § 1990.131 Priority lists for regulating...

  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. AN EVALUATION OF THE HUMAN CARCINOGENIC POTENTIAL OF ETHYLENE GLYCOL BUTYL ETHER: INTERIM FINAL POSITION PAPER

    Science.gov (United States)

    In order to determine the merit of a petition to remove ethylene glycol ether (EGBE) from the Agency's Hazardous Air Pollutant (HAP) list, EPA has developed an interim final position paper, An Evaluation of the Human Carcinogenic Potential of Ethylene Glycol Butyl Ether, t...

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

    NARCIS (Netherlands)

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

    1995-01-01

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

  3. Human bronchus-mediated mutagenesis of mammalian cells by carcinogenic polycyclic aromatic hydrocarbon

    DEFF Research Database (Denmark)

    1978-01-01

    was found in Chinese hamster V-79 cells when they were cocultivated with bronchial explants in the presence of BzaP. The proximate carcinogenic form of BzaP, the 7,8-diol [(+/-)-r7,t8-dihyroxy-7,8-dihydrobenzo[a]pyrene], was 5-fold more potent as a promutagen than the parent compound. Neither BzaP nor...

  4. Rapid screening of potential human bladder carcinogens: genotoxicity in meiosis repair deficient Drosophila melanogaster.

    Science.gov (United States)

    Lamm, L M; Reichert, D F; Lamm, D L

    1989-11-01

    To find a quick screen of potential bladder carcinogens, a genotoxicity test in Drosophila melanogaster stocks containing DNA repair mutations was evaluated. Meiosis repair deficient male Drosophila melanogaster mei-9, mei-41, and the double mutant mei-9-41 were allowed to mate with attached -x females on media containing the test agent. Genotoxic agents produce DNA damage which accumulates and can be lethal in mei males, whereas the attached -x females are able to repair the damage and survive. Thus, the sex ratio of the progeny is a measure of genotoxicity which can be correlated with mutagenicity and carcinogenicity. In this study, tea, coffee, and saccharin were not genotoxic (p greater than 0.3). Dose dependent toxicity was observed in bracken fern (p less than 0.001). The known mutagen and bladder carcinogen, cyclophosphamide, was highly genotoxic (p less than .001). Drosophila genotoxicity not only permits rapid screening of mutagens, but may also have advantages over other systems in the screening of potential bladder carcinogens. PMID:2509735

  5. 40 CFR 799.9430 - TSCA combined chronic toxicity/carcinogenicity.

    Science.gov (United States)

    2010-07-01

    ... Good Laboratory Practice Standards at 40 CFR part 792, subpart J, the following specific information.... The study must be conducted in compliance with 40 CFR Part 792—Good Laborary Practice Standards. (h...) Page, N.P. Chronic Toxicity and Carcinogenicity Guidelines. Journal of Environmental Pathology...

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

    International Nuclear Information System (INIS)

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

  7. 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…

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

    International Nuclear Information System (INIS)

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

  9. [Notion of threshold in mutagenesis: implications for mutagenic and carcinogenic risk assessment].

    Science.gov (United States)

    Marzin, D

    2007-11-01

    During years, it has been widely admitted in the scientific community that there was no threshold in mutagenesis: a compound was or not a mutagen. The meaning of such a proposition was that a risk existed at all exposure level, because, at least theoretically, one molecule is sufficient to cause the formation of a DNA adduct which is able to induce a mutation. However, works carried out in the last few years have shown that in the case of some specific mechanisms of mutagenesis, a threshold could be demonstrated essentially in the case of compounds that do not react directly with DNA. Several types of thresholds exist, and the simple statistical threshold is not sufficient in terms of risk assessment. A biological threshold that is consistent with a mechanism of action of the mutagen should be established. Amongst these mechanisms, we can mention some mechanism with a demonstrated threshold: effects of aneugens, effects of topoisomerases inhibitors, effects of DNA polymerases inhibitors, effects of compounds with a different metabolism at high doses compared to low doses. On the contrary, for some mechanisms, the demonstration of the mechanism is suspected, but not totally demonstrated. It is the case of compounds which induce nucleotides pool imbalance or compounds which are DNA repair inhibitors. In some cases, when a redundancy exists in the repair of damages, like oxidative DNA damage, a threshold is suspected. Some authors even recently proposed the possibility of a threshold in the case of alkylating agents. The majority of mutagenic thresholds were demonstrated in vitro, however some mechanisms were demonstrated in vivo, for example in the case of micronucleus induction by hypo or hyperthermia in rodents bone marrow. The use of threshold in risk assessment requires the use of the most sensitive endpoint for example, non disjunction in the case of aneugens, confusing factors like apoptosis should be eliminated and species sensitivities should be taken into

  10. A common carcinogen benzo[a]pyrene causes neuronal death in mouse via microglial activation.

    Directory of Open Access Journals (Sweden)

    Kallol Dutta

    Full Text Available BACKGROUND: Benzo[a]pyrene (B[a]P belongs to a class of polycyclic aromatic hydrocarbons that serve as micropollutants in the environment. B[a]P has been reported as a probable carcinogen in humans. Exposure to B[a]P can take place by ingestion of contaminated (especially grilled, roasted or smoked food or water, or inhalation of polluted air. There are reports available that also suggests neurotoxicity as a result of B[a]P exposure, but the exact mechanism of action is unknown. METHODOLOGY/PRINCIPAL FINDINGS: Using neuroblastoma cell line and primary cortical neuron culture, we demonstrated that B[a]P has no direct neurotoxic effect. We utilized both in vivo and in vitro systems to demonstrate that B[a]P causes microglial activation. Using microglial cell line and primary microglial culture, we showed for the first time that B[a]P administration results in elevation of reactive oxygen species within the microglia thereby causing depression of antioxidant protein levels; enhanced expression of inducible nitric oxide synthase, that results in increased production of NO from the cells. Synthesis and secretion of proinflammatory cytokines were also elevated within the microglia, possibly via the p38MAP kinase pathway. All these factors contributed to bystander death of neurons, in vitro. When administered to animals, B[a]P was found to cause microglial activation and astrogliosis in the brain with subsequent increase in proinflammatory cytokine levels. CONCLUSIONS/SIGNIFICANCE: Contrary to earlier published reports we found that B[a]P has no direct neurotoxic activity. However, it kills neurons in a bystander mechanism by activating the immune cells of the brain viz the microglia. For the first time, we have provided conclusive evidence regarding the mechanism by which the micropollutant B[a]P may actually cause damage to the central nervous system. In today's perspective, where rising pollution levels globally are a matter of grave concern, our

  11. The carcinogenic risk of high dose total body irradiation in non-human primates

    International Nuclear Information System (INIS)

    High dose total body irradiation (TBI) in combination with chemotherapy, followed by rescue with bone marrow transplantation (BMT), is increasingly used for the treatment of haematological malignancies. With the increasing success of this treatment and its current introduction for treating refractory autoimmune diseases the risk of radiation carcinogenesis is of growing concern. Studies on turnout induction in non-human primates are of relevance in this context since the response of this species to radiation does not differ much from that in man. Since the early sixties, studies have been performed on acute effects in Rhesus monkeys and the protective action of bone marrow transplantation after irradiation with X-rays (average total body dose 6.8 Gy) and fission neutrons (average dose 3.4 Gy). Of those monkeys, which were irradiated and reconstituted with autologous bone marrow, 20 animals in the X-irradiated group and nine animals in the neutron group survived more than 3 years. A group of 21 non-irradiated Rhesus monkeys of a comparable age distribution served as controls. All animals were regularly screened for the occurrence of neoplasms. Complete necropsies were performed after natural death or euthanasia. At post-irradiation intervals of 4-21 years an appreciable number of tumours was observed. In the neutron irradiated group eight out of nine animals died with one or more malignant tumours. In the X-irradiated group this fraction was 10 out of 20. The tumours in the control group, in seven out of the 21 animals, appeared at much older a-e compared with those in the irradiated cohorts. The histogenesis of the tumours was diverse with a preponderance of renal carcinoma, sarcomas among which osteosarcormas, and malignant glomus tumours in the irradiated groups. When corrected for competing risks, the carcinogenic risk of TBI in the Rhesus monkeys is similar to that derived from the studies of the Japanese atomic bomb survivors. The increase of the risk by a

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

    International Nuclear Information System (INIS)

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

  13. 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.

  14. Agaritine content of 53 Agaricus species collected from nature

    DEFF Research Database (Denmark)

    Schulzova, V.; Hajslova, J.; Peroutka, R.;

    2009-01-01

    carcinogen. There was a huge variation in agaritine content between species, but less variation between samples of a species. Whereas the cultivated mushroom Agaricus bisporus commonly contain 200-500 mg agaritine kg-1 fresh weight, no less than 24 of the 53 species contained agaritine levels above 1000 mg...... strain development of Agaricus mushrooms for cultivation. No correlation could be observed between agaritine content and size of the mushroom, week of the year when collected, year of collection, or site of collection. Besides occurring in the genus Agaricus, some species of the genera Leucoagaricus...

  15. Light-Emitting Diodes: A Hidden Treasure

    Science.gov (United States)

    Planinšic, Gorazd; Etkina, Eugenia

    2014-01-01

    LEDs, or light-emitting diodes, are cheap, easy to purchase, and thus commonly used in physics instruction as indicators of electric current or as sources of light (Fig. 1). In our opinion LEDs represent a unique piece of equipment that can be used to collect experimental evidence, and construct and test new ideas in almost every unit of a general…

  16. Fragranced consumer products: Chemicals emitted, ingredients unlisted

    International Nuclear Information System (INIS)

    Fragranced consumer products are pervasive in society. Relatively little is known about the composition of these products, due to lack of prior study, complexity of formulations, and limitations and protections on ingredient disclosure in the U.S. We investigated volatile organic compounds (VOCs) emitted from 25 common fragranced consumer products-laundry products, personal care products, cleaning supplies, and air fresheners-using headspace analysis with gas chromatography/mass spectrometry (GC/MS). Our analysis found 133 different VOCs emitted from the 25 products, with an average of 17 VOCs per product. Of these 133 VOCs, 24 are classified as toxic or hazardous under U.S. federal laws, and each product emitted at least one of these compounds. For 'green' products, emissions of these compounds were not significantly different from the other products. Of all VOCs identified across the products, only 1 was listed on any product label, and only 2 were listed on any material safety data sheet (MSDS). While virtually none of the chemicals identified were listed, this nonetheless accords with U.S. regulations, which do not require disclosure of all ingredients in a consumer product, or of any ingredients in a mixture called 'fragrance.' Because the analysis focused on compounds emitted and listed, rather than exposures and effects, it makes no claims regarding possible risks from product use. Results of this study contribute to understanding emissions from common products, and their links with labeling and legislation.

  17. Possibilities and limitations of sup 1 H and sup 13 C nuclear magnetic resonance spectroscopy for the identification and the quantitative determination of some naturally occurring carcinogenic risk factors. [Senecio vulgaris; Senecio vernalis; Senecio jacobaea; Euphorbia ingens

    Energy Technology Data Exchange (ETDEWEB)

    Pieters, L.

    1988-01-01

    The aim of this work was to develop a phytochemical screening method for some selected carcinogenic or tumor-promoting principles in higher plants. The pyrrolizidine alkaloids from some Senecio species (Compositae or Asteraceae), and the diterpene ester from Croton tiglium L. and Euphorbia ingens E. Mey (Euphorbiaceae) were chosen as representatives of both groups. The possibilities and limitations of {sup 1}H and {sup 13}C nuclear magnetic resonance spectroscopy ({sup 1}H and {sup 13}C NMR) for the analysis of mixtures of carcinogenic pyrrolizidine alkaloids were compared with high performance liquid chromatography, and gas chromatography with high performance liquid chromatography, and gas chromatography was well as gas chromatography - mass spectrometry. Senecio vulgaris L., Senecio vernalis Waldst. and Kit. and Senecio jacobaea L. were investigated.

  18. Hybrid light emitting transistors (Presentation Recording)

    Science.gov (United States)

    Muhieddine, Khalid; Ullah, Mujeeb; Namdas, Ebinazar B.; Burn, Paul L.

    2015-10-01

    Organic light-emitting diodes (OLEDs) are well studied and established in current display applications. Light-emitting transistors (LETs) have been developed to further simplify the necessary circuitry for these applications, combining the switching capabilities of a transistor with the light emitting capabilities of an OLED. Such devices have been studied using mono- and bilayer geometries and a variety of polymers [1], small organic molecules [2] and single crystals [3] within the active layers. Current devices can often suffer from low carrier mobilities and most operate in p-type mode due to a lack of suitable n-type organic charge carrier materials. Hybrid light-emitting transistors (HLETs) are a logical step to improve device performance by harnessing the charge carrier capabilities of inorganic semiconductors [4]. We present state of the art, all solution processed hybrid light-emitting transistors using a non-planar contact geometry [1, 5]. We will discuss HLETs comprised of an inorganic electron transport layer prepared from a sol-gel of zinc tin oxide and several organic emissive materials. The mobility of the devices is found between 1-5 cm2/Vs and they had on/off ratios of ~105. Combined with optical brightness and efficiencies of the order of 103 cd/m2 and 10-3-10-1 %, respectively, these devices are moving towards the performance required for application in displays. [1] M. Ullah, K. Tandy, S. D. Yambem, M. Aljada, P. L. Burn, P. Meredith, E. B. Namdas., Adv. Mater. 2013, 25, 53, 6213 [2] R. Capelli, S. Toffanin, G. Generali, H. Usta, A. Facchetti, M. Muccini, Nature Materials 2010, 9, 496 [3] T. Takenobu, S. Z. Bisri, T. Takahashi, M. Yahiro, C. Adachi, Y. Iwasa, Phys. Rev. Lett. 2008, 100, 066601 [4] H. Nakanotani, M. Yahiro, C. Adachi, K. Yano, Appl. Phys. Lett. 2007, 90, 262104 [5] K. Muhieddine, M. Ullah, B. N. Pal, P. Burn E. B. Namdas, Adv. Mater. 2014, 26,37, 6410

  19. Auger Emitting Radiopharmaceuticals for Cancer Therapy

    Science.gov (United States)

    Falzone, Nadia; Cornelissen, Bart; Vallis, Katherine A.

    Radionuclides that emit Auger electrons have been of particular interest as therapeutic agents. This is primarily due to the short range in tissue, controlled linear paths and high linear energy transfer of these particles. Taking into consideration that ionizations are clustered within several cubic nanometers around the point of decay the possibility of incorporating an Auger emitter in close proximity to the cancer cell DNA has immense therapeutic potential thus making nuclear targeted Auger-electron emitters ideal for precise targeting of cancer cells. Furthermore, many Auger-electron emitters also emit γ-radiation, this property makes Auger emitting radionuclides a very attractive option as therapeutic and diagnostic agents in the molecular imaging and management of tumors. The first requirement for the delivery of Auger emitting nuclides is the definition of suitable tumor-selective delivery vehicles to avoid normal tissue toxicity. One of the main challenges of targeted radionuclide therapy remains in matching the physical and chemical characteristics of the radionuclide and targeting moiety with the clinical character of the tumor. Molecules and molecular targets that have been used in the past can be classified according to the carrier molecule used to deliver the Auger-electron-emitting radionuclide. These include (1) antibodies, (2) peptides, (3) small molecules, (4) oligonucleotides and peptide nucleic acids (PNAs), (5) proteins, and (6) nanoparticles. The efficacy of targeted radionuclide therapy depends greatly on the ability to increase intranuclear incorporation of the radiopharmaceutical without compromising toxicity. Several strategies to achieve this goal have been proposed in literature. The possibility of transferring tumor therapy based on the emission of Auger electrons from experimental models to patients has vast therapeutic potential, and remains a field of intense research.

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

    OpenAIRE

    Marchant, C A

    1996-01-01

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

  1. European medicinal and edible plants associated with subacute and chronic toxicity part I: Plants with carcinogenic, teratogenic and endocrine-disrupting effects.

    Science.gov (United States)

    Kristanc, Luka; Kreft, Samo

    2016-06-01

    In recent decades, the use of herbal medicines and food products has been widely embraced in many developed countries. These products are generally highly accepted by consumers who often believe that "natural" equals "safe". This is, however, an oversimplification because several botanicals have been found to contain toxic compounds in concentrations harmful to human health. Acutely toxic plants are in most cases already recognised as dangerous as a result of their traditional use, but plants with subacute and chronic toxicity are difficult or even impossible to detect by traditional use or by clinical research studies. In this review, we systematically address major issues including the carcinogenicity, teratogenicity and endocrine-disrupting effects associated with the use of herbal preparations with a strong focus on plant species that either grow natively or are cultivated in Europe. The basic information regarding the molecular mechanisms of the individual subtypes of plant-induced non-acute toxicity is given, which is followed by a discussion of the pathophysiological and clinical characteristics. We describe the genotoxic and carcinogenic effects of alkenylbenzenes, pyrrolizidine alkaloids and bracken fern ptaquiloside, the teratogenicity issues regarding anthraquinone glycosides and specific alkaloids, and discuss the human health concerns regarding the phytoestrogens and licorice consumption in detail. PMID:27090581

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

    Directory of Open Access Journals (Sweden)

    Batlle Alcira

    2006-12-01

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

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

    Mani, Sujata; Bharagava, Ram Naresh

    2016-01-01

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

  5. Dislocation engineered silicon light emitting devices

    International Nuclear Information System (INIS)

    The influence of boron-induced dislocation loops on the luminescence efficiency of silicon-based light-emitting diodes is investigated. Luminescence measurements and transmission-electron-microscopy images from devices fabricated by boron implantation into crystalline silicon, and subsequently processed under different conditions to form dislocation loops of different size and densities, were compared. Light emitting devices were also fabricated in an otherwise identical but a pre-amorphized substrate, to prevent boron-induced loop formation. The results demonstrate a strong correlation between the dislocation loop density and areal coverage, and the light emission efficiency. The devices produced in the pre-amorphized substrate, without dislocation loops, show strongly quenched light emission

  6. SUMER: Solar Ultraviolet Measurements of Emitted Radiation

    Science.gov (United States)

    Wilhelm, K.; Axford, W. I.; Curdt, W.; Gabriel, A. H.; Grewing, M.; Huber, M. C. E.; Jordan, S. D.; Kuehne, M.; Lemaire, P.; Marsch, E.

    1992-01-01

    The experiment Solar Ultraviolet Measurements of Emitted Radiation (SUMER) is designed for the investigations of plasma flow characteristics, turbulence and wave motions, plasma densities and temperatures, structures and events associated with solar magnetic activity in the chromosphere, the transition zone and the corona. Specifically, SUMER will measure profiles and intensities of Extreme Ultraviolet (EUV) lines emitted in the solar atmosphere ranging from the upper chromosphere to the lower corona; determine line broadenings, spectral positions and Doppler shifts with high accuracy, provide stigmatic images of selected areas of the Sun in the EUV with high spatial, temporal and spectral resolution and obtain full images of the Sun and the inner corona in selectable EUV lines, corresponding to a temperature from 10,000 to more than 1,800,000 K.

  7. UVC emitting phosphors obtained by spray pyrolysis

    International Nuclear Information System (INIS)

    The broadband inter-configurational (4f15d1→4f2) emission of Pr3+ doped in lanthanum orthophosphate (LaPO4) and in calcium pyrophosphate (Ca2P2O7) has been investigated under plasma excitation. The synthesis by spray pyrolysis at moderate temperature followed by a controlled annealing proves to be a very efficient way to produce good quality UVC emitting phosphor Ca1.92Pr0.04Na0.04P2O7 (α phase). The emission of this phosphor in the wavelength range 200-350 nm has been measured with a prototype device, which can be employed for anti-microbial testing. - Research Highlights: → The Pr3+ doped orthophosphate and pyrophosphate were synthesized by spray pyrolysis. → The dense particles present good quality UVC emitting (200-350 nm). → The prototype device can be employed for anti-microbial testing.

  8. Biointegrated flexible inorganic light emitting diodes

    OpenAIRE

    Lee, Keon Jae

    2012-01-01

    Min Koo, So Young Park, Keon Jae LeeDepartment of Materials Science and Engineering, Korea Advanced Institute of Science and Technology, Yuseong-gu, Daejeon, Republic of KoreaAbstract: The use of light-emitting diodes (LEDs) as therapeutic tools has been actively studied over the past few decades due to their advantages of high safety, low cost, excellent portability, and wide bandwidth. In addition, their application in biomedical fields has been expanded to such areas as nerve stimulation, ...

  9. Researches of odour emitted by household waste

    OpenAIRE

    Eglė Marčiulaitienė; Tadas Lukauskas

    2015-01-01

    The article deals with odour emitted by household waste, the chemical composition of household waste. The experiment was made with food waste (1000 g) placed in 5 litter containers. Food waste was containing products of animal origin (meat, fish, dairy products) and plant origin (vegetables, fruit) waste. Time of the experiment was 14 days 19±3 °C at environment temperature. Odour concentration is determined by dynamic olfactometry method. Studies have shown that the strongest odour of all ho...

  10. Bioinspired Hybrid White Light-Emitting Diodes.

    Science.gov (United States)

    Weber, Michael D; Niklaus, Lukas; Pröschel, Marlene; Coto, Pedro B; Sonnewald, Uwe; Costa, Rubén D

    2015-10-01

    The first bioinspired hybrid white-light-emitting diodes (bio-HLEDs) featuring protein cascade coatings are presented. For easy fabrication a new strategy to stabilize proteins in rubber-like material was developed. The synergy between the excellent features of fluorescent proteins and the easily processed rubber produces bio-HLEDs with less than 10% loss in luminous efficiency over 100 hours. PMID:26271025

  11. Approaches to blue light emitting polymers

    International Nuclear Information System (INIS)

    Blue-light emitting polymers are important for full colour displays. Blue- light emitting polymers, such as poly(fluorene)s have been reported, but tend to be soluble in the conjugated form. The aim of the project was to produce insoluble polymers, prepared via processible soluble precursor polymers, so that multilayer devices could be easily fabricated. Multilayer devices are often required for more efficient light emission. The target materials were derivatives of poly(p-phenylenevinylene) (PPV), a green-yellow emitting polymer. To blue shift the emission of PPV, bulky substituents, namely chloro, phenyl and alkyl, were attached to the vinylic linkage. These bulky substituents were incorporated to introduce steric interactions between the side group and the backbone phenyl protons, to shorten the effective conjugation length and increase the HOMO-LUMO energy gap. Chloro substituents quenched the fluorescence. Phenyl substituents resulted in highly conjugated precursor polymers with low molecular weights, showing blue- green to green emission in the conjugated form. Alkyl substituted PPV derivatives, prepared via chloro or xanthate precursors, were blue-light emitting conjugated polymers, which were electroluminescent in ITO/polymer/AI devices. The PL quantum yields were found to be up to 38%. The incorporation of electron withdrawing groups into the polymers was attempted, to lower the barrier to electron injection. Chloro groups quenched fluorescence and methylsulfone substituents resulted in insoluble polymers, probably due to cross-linking. However a copolymer containing methylsulfone electron withdrawing groups could be prepared. Phenylsulfone substituents were found to give fluorescent polymers which were soluble in the precursor form. (author)

  12. Materials engineering for polarized light emitting diodes

    Czech Academy of Sciences Publication Activity Database

    Wegner, G.; Neher, D.; Remmers, M.; Cimrová, Věra; Schulze, M.

    Keystone: Materials Research Society, 1995 - (Lee, C.; Dalton, L.), s. 23-34 ISBN 1-55899-316-9. [Materials Research Society Fall Meeting: Electrical, Optical, and Magnetic Properties of Organic Solid State Materials. Boston (US), 26.11.1995-1.12.1995] Institutional research plan: CEZ:AV0Z4050913 Keywords : soluble poly(p-phenylene) * polarized emission * light emitting diodes(LED) Subject RIV: CD - Macromolecular Chemistry

  13. Researches of odour emitted by household waste

    Directory of Open Access Journals (Sweden)

    Eglė Marčiulaitienė

    2015-10-01

    Full Text Available The article deals with odour emitted by household waste, the chemical composition of household waste. The experiment was made with food waste (1000 g placed in 5 litter containers. Food waste was containing products of animal origin (meat, fish, dairy products and plant origin (vegetables, fruit waste. Time of the experiment was 14 days 19±3 °C at environment temperature. Odour concentration is determined by dynamic olfactometry method. Studies have shown that the strongest odour of all household waste used in this experiment was emitted by meat and fish waste (76 444 OUE/m3. Meat and fish waste emits the strongest odour as waste contains proteins, their decomposition releases into the environment a strong unpleasant odour, hydrogen sulphide and ammonia. Protein degradation releases into the environment are, characterized by a strong unpleasant smell of hydrogen sulphide and ammonia gas. During the anaerobic decomposition of organic matter a variety of other fragrant compounds: alcohols (e.g., ethanol and methanol, vinegar, formic acid, etc. is found.

  14. Does antimatter emit a new light?

    Science.gov (United States)

    Santilli, Ruggero Maria

    1997-08-01

    Contemporary theories of antimatter have a number of insufficiencies which stimulated the recent construction of the new isodual theory based on a certain anti-isomorphic map of all (classical and quantum) formulations of matter called isoduality. In this note we show that the isodual theory predicts that antimatter emits a new light, called isodual light, which can be distinguished from the ordinary light emitted by matter via gravitational interactions (only). In particular, the isodual theory predicts that all stable antiparticles such as the isodual photon, the positron and the antiproton experience antigravity in the field of matter (defined as the reversal of the sign of the curvature tensor). The antihydrogen atom is therefore predicted to: experience antigravity in the field of Earth; emit the isodual photon; and have the same spectroscopy of the hydrogen atom, although subjected to an anti-isomorphic isodual map. In this note we also show that the isodual theory predicts that bound states of elementary particles and antiparticles (such as the positronium) experience ordinary gravitation in both fields of matter and antimatter, thus bypassing known objections against antigravity. A number of intriguing and fundamental, open theoretical and experimental problems of “the new physics of antimatter” are pointed out.

  15. Does antimatter emit a new light?

    International Nuclear Information System (INIS)

    Contemporary theories of antimatter have a number of insufficiencies which stimulated the recent construction of the new isodual theory based on a certain anti-isomorphic map of all (classical and quantum) formulations of matter called isoduality. In this note we show that the isodual theory predicts that antimatter emits a new light, called isodual light, which can be distinguished from the ordinary light emitted by matter via gravitational interactions (only). In particular, the isodual theory predicts that all stable antiparticles such as the isodual photon, the positron and the antiproton experience antigravity in the field of matter (defined as the reversal of the sign of the curvature tensor). The antihydrogen atom is therefore predicted to: experience antigravity in the field of Earth; emit the isodual photon; and have the same spectroscopy of the hydrogen atom, although subjected to an anti-isomorphic isodual map. In this note we also show that the isodual theory predicts that bound states of elementary particles and antiparticles (such as the positronium) experience ordinary gravitation in both fields of matter and antimatter, thus bypassing known objections against antigravity. A number of intriguing and fundamental, open theoretical and experimental problems of 'the new physics of antimatter' are pointed out

  16. Does antimatter emit a new light?

    Energy Technology Data Exchange (ETDEWEB)

    Santilli, Ruggero Maria [Instituto per la Ricerca di Base (Italy)

    1997-08-15

    Contemporary theories of antimatter have a number of insufficiencies which stimulated the recent construction of the new isodual theory based on a certain anti-isomorphic map of all (classical and quantum) formulations of matter called isoduality. In this note we show that the isodual theory predicts that antimatter emits a new light, called isodual light, which can be distinguished from the ordinary light emitted by matter via gravitational interactions (only). In particular, the isodual theory predicts that all stable antiparticles such as the isodual photon, the positron and the antiproton experience antigravity in the field of matter (defined as the reversal of the sign of the curvature tensor). The antihydrogen atom is therefore predicted to: experience antigravity in the field of Earth; emit the isodual photon; and have the same spectroscopy of the hydrogen atom, although subjected to an anti-isomorphic isodual map. In this note we also show that the isodual theory predicts that bound states of elementary particles and antiparticles (such as the positronium) experience ordinary gravitation in both fields of matter and antimatter, thus bypassing known objections against antigravity. A number of intriguing and fundamental, open theoretical and experimental problems of 'the new physics of antimatter' are pointed out.

  17. Does antimatter emit a new light?

    International Nuclear Information System (INIS)

    Contemporary theories of antimatter have a number of insufficiencies which stimulated the recent construction of the new isodual theory based on a certain anti-isomorphic map of all (classical and quantum) formulations of matter called isoduality. In this note we show that the isodual theory predicts that antimatter emits a new light, called isodual light, which can be distinguished from the ordinary light emitted by matter via gravitational interactions (only). In particular, the isodual theory predicts that all stable antiparticles such as the isodual photon, the positron and the antiproton experience antigravity in the field of matter (defined as the reversal of the sign of the curvature tensor). The antihydrogen atom is therefore predicted to: experience antigravity in the field of Earth; emit the isodual photon; and have the same spectroscopy of the hydrogen atom, although subjected to an anti-isomorphic isodual map. In this note we also show that the isodual theory predicts that bound states of elementary particle sand antiparticles (such as the positronium) experience ordinary gravitation in both fields of matter and antimatter, thus by passing known objections against antigravity. A number of intriguing and fundamental, open theoretical and experimental problems of 'the new physics of antimatter' are pointed out. 16 refs

  18. [Carcinogenic risk of polycyclic aromatic hydrocarbons: classification and interpretation of the monitoring].

    Science.gov (United States)

    Catalani, Simona; Fostinelli, Jacopo; Apostoli, Pietro

    2014-01-01

    The polycyclic aromatic hydrocarbons (PAHs) are widespread contaminants characterized by various chemical, physical and toxic properties. The characterization of occupational and environmental exposures and the use of suitable measurements protocols are very significant because their presence in mixtures and environmental persistency. In the past few years, the knowledge concerning carcinogenicity of PAHs have been reviewed, the mechanisms involved are the interaction of PAH's metabolites with DNA and oxidative damages. The main requirement for research concerns lack of knowledge on reference values and occupational exposure's assessment in particular PAHs sampling methods that can lead to combined measurements of vapor and aerosol mixtures. Aims of this study are to describe a possible occupational sources of PAHs providing also an update of mechanism involved in their carcinogenicity and risk calculation as is done in the TEF approach. The classifications provided by International Agencies and Institutions and the limit values adopted have been reviewed and taken into account. PMID:25369710

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  1. Oxidative damage by carcinogenic polycyclic aromatic hydrocarbons and organic extracts from urban air particulate matter

    Czech Academy of Sciences Publication Activity Database

    Hanzalová, Kateřina; Rössner ml., Pavel; Šrám, Radim

    2010-01-01

    Roč. 696, č. 2 (2010), s. 114-121. ISSN 1383-5718 R&D Projects: GA MŠk 2B08005; GA MŽP(CZ) SP/1B3/8/08 Institutional research plan: CEZ:AV0Z50390512 Keywords : carcinogenic polycyclic aromatic hydrocarbons * oxidative damage in vitro * extractable organic matter Subject RIV: DN - Health Impact of the Environment Quality Impact factor: 2.938, year: 2010

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

    Directory of Open Access Journals (Sweden)

    Johannes Eichner

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

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

    Science.gov (United States)

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

    2016-08-01

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

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

    OpenAIRE

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

    1993-01-01

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

  5. Evaluation of the potential carcinogenic action of radiocalcium internal irradiation in Swiss albino mice

    International Nuclear Information System (INIS)

    The carcinogenic action of 45Ca on inducing hepatocelluar carcinoma (HCC) in Swiss albino mice has been statistically evaluated. HCC proved to be radiation-induced and not due to spontaneous origin. Also, the higher incidence of male hepatocarcinogenesis due to internal irradiation has been found to be significant. The precise possible mechanism regarding the higher male susceptibility to liver cancer has been discussed in the light of available literature. (author)

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

    OpenAIRE

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

    2016-01-01

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

  7. Nicotine: Carcinogenicity and Effects on Response to Cancer Treatment – A Review

    OpenAIRE

    Sanner, Tore; Tom K Grimsrud

    2015-01-01

    Tobacco use is considered the single most important man-made cause of cancer that can be avoided. The evidence that nicotine is involved in cancer development is reviewed and discussed in this paper. Both tobacco smoke and tobacco products for oral use contain a number of carcinogenic substances, such as polycyclic hydrocarbons and tobacco-specific N-nitrosamines (TSNA), which undoubtedly contribute to tobacco related cancer. Recent studies have shown that nicotine can affect several importan...

  8. Clinical and biochemical studies support smokeless tobacco’s carcinogenic potential in the human oral cavity

    OpenAIRE

    Mallery, Susan R.; Tong, Meng; Michaels, Gregory C.; Kiyani, Amber R.; Hecht, Stephen S

    2013-01-01

    In 2007, International Agency for Cancer Research presented compelling evidence that linked smokeless tobacco use to the development of human oral cancer. While these findings imply vigorous local carcinogen metabolism, little is known regarding levels and distribution of Phase I, II and drug egress enzymes in human oral mucosa. In the study presented here, we integrated clinical data, imaging and histopathologic analyses of an oral squamous cell carcinoma that arose at the site of smokeless ...

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

    International Nuclear Information System (INIS)

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

  10. Carcinogens induce reversion of the mouse pink-eyed unstable mutation

    OpenAIRE

    Schiestl, Robert H.; Aubrecht, Jiri; Khogali, Fathia; Carls, Nicholas

    1997-01-01

    Deletions and other genome rearrangements are associated with carcinogenesis and inheritable diseases. The pink-eyed unstable (pun) mutation in the mouse is caused by duplication of a 70-kb internal fragment of the p gene. Spontaneous reversion events in homozygous pun/pun mice occur through deletion of a duplicated sequence. Reversion events in premelanocytes in the mouse embryo detected as black spots on the gray fur of the offspring were inducible by the carcinogen x-rays, ethyl methanesul...

  11. Urban air pollution by carcinogenic and genotoxic polyaromatic hydrocarbons in the former USSR.

    OpenAIRE

    Khesina AYa,

    1994-01-01

    The content of major carcinogenic and genotoxic polyaromatic hydrocarbons (PAH) in urban air, vehicle, and industrial emissions is assessed. A sensitive, specific, and selective method for PAH and nitro-PAH quantitation was developed on the basis of low-temperature luminescence-spectra of frozen polycrystalline solutions. Polyarene contents in urban air and urban industrial emissions, as well as vehicle exhausts, are compared to the Russian Ministry of Health standard of maximal permissible c...

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

    Institute of Scientific and Technical Information of China (English)

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

    2002-01-01

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

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

    Science.gov (United States)

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

    2015-07-01

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

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

    International Nuclear Information System (INIS)

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

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

    OpenAIRE

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

    2009-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Lijinsky, W.; Taylor, H.W.

    1976-01-01

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

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

    OpenAIRE

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

    2007-01-01

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

  19. Bioavailability and potential carcinogenicity of polycyclic aromatic hydrocarbons from wood combustion particulate matter in vitro.

    Science.gov (United States)

    Gauggel-Lewandowski, Susanne; Heussner, Alexandra H; Steinberg, Pablo; Pieterse, Bart; van der Burg, Bart; Dietrich, Daniel R

    2013-11-25

    Due to increasing energy demand and limited fossil fuels, renewable energy sources have gained in importance. Particulate matter (PM) in general, but also PM from the combustion of wood is known to exert adverse health effects in human. These are often related to specific toxic compounds adsorbed to the PM surface, such as polycyclic aromatic hydrocarbons (PAH), of which some are known human carcinogens. This study focused on the bioavailability of PAHs and on the tumor initiation potential of wood combustion PM, using the PAH CALUX® reporter gene assay and the BALB/c 3T3 cell transformation assay, respectively. For this, both cell assays were exposed to PM and their respective organic extracts from varying degrees of combustion. The PAH CALUX® experiments demonstrated a concentration-response relationship matching the PAHs detected in the samples. Contrary to expectations, PM samples from complete (CC) and incomplete combustion (IC) provided for a stronger and weaker response, respectively, suggesting that PAH were more readily bioavailable in PM from CC. These findings were corroborated via PAH spiking experiments indicating that IC PM contains organic components that strongly adsorb PAH thereby reducing their bioavailability. The results obtained with organic extracts in the cell transformation assay presented the highest potential for carcinogenicity in samples with high PAH contents, albeit PM from CC also demonstrated a carcinogenic potential. In conclusion, the in vitro assays employed emphasize that CC produces PM with low PAH content however with a general higher bioavailability and thus with a nearly similar carcinogenic potential than IC PM. PMID:23796820

  20. A one-electron oxidation of carcinogenic nonaminoazo dye Sudan I by horseradish peroxidase

    Czech Academy of Sciences Publication Activity Database

    Semanská, M.; Dračínský, Martin; Martínek, V.; Hudeček, J.; Hodek, P.; Frei, E.; Stiborová, M.

    2008-01-01

    Roč. 29, č. 5 (2008), s. 712-716. ISSN 0172-780X Grant ostatní: GA MŠk(CZ) 1M0505; GA ČR(CZ) GA203/06/0329 Institutional research plan: CEZ:AV0Z40550506 Keywords : carcinogen * Sudan I * peroxidase * NMR spectroscopy * mechanism of oxidation Subject RIV: CC - Organic Chemistry Impact factor: 1.359, year: 2008 http://node.nel.edu

  1. The role of the Akt/mTOR pathway in tobacco-carcinogen induced lung tumorigenesis

    OpenAIRE

    Memmott, Regan M.; Dennis, Phillip A.

    2009-01-01

    Lung cancer is the leading cause of cancer-related death in the United States, and 85–90% of lung cancer cases are associated with tobacco use. Tobacco components promote lung tumorigenesis through genotoxic effects, as well as through biochemical modulation of signaling pathways such as the Akt/mTOR pathway that regulate cell proliferation and survival. This review will describe cell surface receptors and other upstream components required for tobacco-carcinogen induced activation of Akt and...

  2. A Comparative Survey on Parameters Influencing on Hexavalent Chromium Measurement as an Occupational Carcinogen

    OpenAIRE

    A. Tirgar; F. Golbabaie; S.J. Shahtaheri; K. Nori; J. Hamedi; Ganjali, M.R.

    2008-01-01

    Introduction & Objective: Hexavalent chromium, Cr+6, is a very harmful pollutant and a relatively unstable compound that is present in many industries. It is a known human respiratory carcinogen and occupational exposure to this chemical is associated with different health hazards. The purpose of this study was to evaluate the effects of four parameters including: type of sampling head, sampling height from the surface of electroplating solution, sampling duration, and sample storage duration...

  3. Studies on the biological effects of internal exposure of alpha emitters. Carcinogenicity test of plutonium

    International Nuclear Information System (INIS)

    Outlines of carcinogenicity tests in animals given with injected or inhaled plutonium (Pu) were described. Insoluble 239PuO2 particles were nasally inhaled in rats maintained for life. The dose response relationship between incidence of their lung tumor and absorbed radiation dose in the lung revealed that>1 Gy dose increased the incidence of malignant lung tumors, which differed from findings in the U.S. probably due to the difference between particle sizes. Further, a carcinogenic mechanism specific for alpha-ray was suggested based on tumor-related gene analysis. After soluble 239Pu (citrate salt) was injected in mice, significant reduction of lifetime and early tumor- or non-tumor-death were observed when the bone dose exceeded 3 Gy. Tumors were mostly osteosarcoma, lymphoma and other soft tissue solid cancers and were different from those induced by gamma-ray, X-ray and neutron irradiation. Studies on the strain difference, on the carcinogenic mechanism and alpha-ray induced mutation and transformation are in progress, which may lead to elucidation of the biological effects of internal exposure of alpha-emitters. (K.H.)

  4. An update on direct genotoxicity as a molecular mechanism of ochratoxin a carcinogenicity.

    Science.gov (United States)

    Pfohl-Leszkowicz, Annie; Manderville, Richard A

    2012-02-20

    Ochratoxin A (OTA) is a naturally occurring chlorophenolic fungal toxin that contaminates a wide range of food products and poses a cancer threat to humans. The mechanism of action (MOA) for OTA renal carcinogenicity is a controversial issue. In 2005, direct genotoxicity (covalent DNA adduct formation) was proposed as a MOA for OTA-mediated carcinogenicity [ Manderville , R. A. ( 2005 ) Chem. Res. Toxicol. 18 , 1091 - 1097 ]. At that time, inconsistent results had been published on OTA genotoxicity/mutagenicity, and conclusive evidence for OTA-mediated DNA adduction had been lacking. In this update, published data from the past 6-7 years are presented that provide new hypotheses for the MOA of OTA-mediated carcinogenicity. While direct genotoxicity remains a controversial issue for OTA, new findings from the Umemura and Nohmi laboratories provide definitive results for the mutagenicity of OTA in the target tissue (outer medulla) of male rat kidney that rules out oxidative DNA damage. These findings, coupled with our own efforts that provide new structural evidence for DNA adduction by OTA, has strengthened the argument for involvement of direct genotoxicity in OTA-mediated renal carcinogenesis. This MOA should be taken into consideration for OTA human risk assessment. PMID:22054007

  5. Inhibitory effect of diet related sulphydryl compounds on the formation of carcinogenic nitrosamines.

    Science.gov (United States)

    Shenoy, N R; Choughuley, A S

    1992-08-31

    N-Nitroso compounds (NOCs) are known to be strong carcinogens in various animals including primates (Preussman and Stewart, (1984) N-Nitroso Compounds). Human exposure to these compounds can be by ingestion or inhalation of preformed NOCs or by endogenous nitrosation from naturally occurring precursors (Bartsch and Montesano, Carcinogenesis, 5 (1984) 1381-1393; Tannebaum (1979) Naturally Occuring Carcinogens, Mutagens and Modulators of Carcinogenesis; Shephard et al., Food Chem. Toxicol., 25 (1987) 91-108). Several factors present in the diet can modify levels of endogenously formed nitrosamines by acting as catalysts or inhibitors. Compounds in the human diet that alter nitrosamine formation would thus play an important role in carcinogenesis study. Earlier researchers have reported the nitrite scavenging nature of sulphydryl compounds (Williams, Chem. Soc. Rev., 15 (1983) 171-196). We therefore studied the modifying effect of sulphydryl compounds viz., cysteine (CE), cystine (CI), glutathione (GU), cysteamine (CEA), cystamine (CEI), cysteic acid (CIA) and thioglycolic acid (TGA) on the nitrosation of model amines viz., pyrrolidine (PYR), piperidine (NPIP) and morpholine (NMOR). Many of these compounds are present in the food we consume. The present work also describes the inhibitory effect of onion and garlic juices on the nitrosation reactions. Both onion and garlic are known to contain sulphur compounds (Block, Sci. Am., 252 (1985) 114-119). Most of these compounds behave as antinitrosating agents and their inhibitory activity towards formation of carcinogenic nitrosamines, under different conditions is described. PMID:1516037

  6. Carcinogenic effects of MGP-7 and B(a)P on the Hamster Cheek Pouch

    Energy Technology Data Exchange (ETDEWEB)

    Brandon, J.L.; Conti, C.J.; Goldstein, L.S.; DiGiovanni, J.; Gimenez-Conti, I.B. [University of Texas MD Anderson Cancer Center, Smithville, TX (United States). Dept. of Carcinogenesis

    2009-10-15

    This study was performed to examine the carcinogenic effects of benzo(a)pyrene (B(a)P) and manufactured gas plant (MGP) residues on the hamster cheek pouch (HCP). Syrian hamsters were treated topically with a suspension of 2%, 10%, or 20% B(a)P or 50% or 100% MGP-7 (a mixture of residues from 7 MGP sites) in mineral oil for eight (short-term study) and sixteen, twenty, twenty-eight, and thirty-two weeks (long-term study). The short-term study showed that B(a)P induced p53 protein accumulation, indicative of genotoxic damage, as well as increased cell proliferation, hyperplasia, and inflammation, which is usually associated with promotional activity. In contrast, the MGP-7 presented only marginal p53 accumulation and induction of BrdU incorporation. In the long-term experiments, animals treated with 2% and 10% of B(a)P continued to show p53 protein accumulation as well as hyperplasia and increased cell proliferation and inflammation. By thirty weeks, all the animals treated with B(a)P had a 100% incidence of squamous cell carcinoma (SCC). Animals treated with 50% and 100% MGP-7 showed only weak hyperplasia and a low proliferation rate and accumulation of p53 protein through thirty-two weeks. Benzo(a)pyrene was highly carcinogenic when used at adequate doses. Manufactured gas plant residue, however, was not carcinogenic in this model.

  7. Synthesis, structural characterization and anti-carcinogenic activity of new cyclotriphosphazenes containing dioxybiphenyl and chalcone groups

    Science.gov (United States)

    Görgülü, Ahmet Orhan; Koran, Kenan; Özen, Furkan; Tekin, Suat; Sandal, Süleyman

    2015-05-01

    2,2-Dichloro-4,4,6,6-bis[spiro(2‧,2″-dioxy-1‧,1″-biphenylyl]cyclotriphosphazene (2) was synthesized from hexachlorocyclotriphosphazene (HCCP) and 2,2‧-dihydroxybiphenyl. The mixed substituent chalcone/dioxybiphenyl cyclophosphazenes (2a-h) were obtained from the reactions of (2) with hydroxy chalcone compounds in K2CO3/acetone system. The chalcone-cyclophosphazene compounds were characterized by elemental analysis, FT-IR, 1H, 13C, 31P NMR techniques. In vitro anti-carcinogenic activities of all compounds were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Anti-carcinogenic activity of the compounds (2a-h) against androgen-dependent (LNCaP) and independent (PC-3) human prostate cancer cell lines were investigated. Our results indicate that the chalcone-phosphazene compounds (2a-h) have anti-carcinogenic activity on PC-3 and LNCaP cell lines (p < 0.05). The effective dose of the compounds was determined as 100 μM.

  8. Chronic Dermal Toxicity of Epoxy Resins I. Skin Carcinogenic Potency and General Toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Holland, J.M.

    2001-01-16

    Epoxy resins are a diverse class of chemicals that differ in structure, physical properties, and, presumably, biological activity. The purpose of these experiments was to compare the chronic dermal toxicity and carcinogenicity of selected commercial epoxy resins and to determine the potential for positive synergistic carcinogenic interactions between different resins. This work is an extension and continuation of a Department of Energy sponsored program to evaluate epoxy resins for potential occupational health risks. The materials examined were chosen on the basis of their interest to the U.S. government. They are representative of the manufacturer's production at the time, and therefore the data are completely valid only for the specific production period. Results of the experimental exposures will be reported in two parts. This report describes the test materials, their chemical and physical characteristics and the experimental design. General (systemic) toxicity will be evaluated and the skin carcinogenicity of the materials compared. A subsequent report will provide morphological descriptions of skin and significant internal pathology induced by the various treatments.

  9. Human hair follicles, a convenient tissue for genetic studies on carcinogen metabolism

    International Nuclear Information System (INIS)

    Basal levels of benzo(a)pyrene metabolism were measured in hair follicles of seven monozygotic twins, eight dizygotic twins and ten pairs of unrelated individuals. Organic soluble metabolites were separated by thin-layer chromatography, visualised by autoradiography and quantified by scanning of the films. Activity was expressed as pmol 7,8- and 9,10-dihydrodiol metabolites of benzo(a)pyrene per μg DNA per hour. Intra-twin differences in benzo(a)pyrene metabolism for monozygotic twins were smaller than for dizygotic twins and intra-pair differences for dizygotic twins were smaller than for pairs of unrelated individuals. The results clearly suggest that individual differences in benzo(a)pyrene metabolism in hair follicles are partly genetically determined. Thus, hair follicles my be used for investigations on the suggested relations between genetic predisposition to carcinogen-induced cancer and individual differences in carcinogen metabolism. The relevance of these findings to research into the induction of neoplasms by carcinogens in epithelial tissues is discussed. (author)

  10. The AlGaAs light emitting particle detector

    Energy Technology Data Exchange (ETDEWEB)

    Pozela, J. E-mail: pozela@uj.pfi.lt; Pozela, K.; Silenas, A.; Juciene, V.; Dapkus, L.; Jasutis, V.; Tamulaitis, G.; Zukauskas, A.; Bendorius, R.-A

    1999-09-11

    An AlGaAs light emitting particle detector was fabricated and investigated experimentally. Light emitting semiconductor Al{sub x}Ga{sub 1-x}As layers with graded-gap energy band structure were grown, and luminescence spectra were investigated. A light emitting X-ray detector was also fabricated. (author)

  11. The AlGaAs light emitting particle detector

    CERN Document Server

    Pozela, J; Silenas, A; Juciene, V; Dapkus, L; Jasutis, V; Tamulaitis, G; Zukauskas, A; Bendorius, R A

    1999-01-01

    An AlGaAs light emitting particle detector was fabricated and investigated experimentally. Light emitting semiconductor Al sub x Ga sub 1 sub - sub x As layers with graded-gap energy band structure were grown, and luminescence spectra were investigated. A light emitting X-ray detector was also fabricated. (author)

  12. 78 FR 68849 - Draft Current Intelligence Bulletin “Update of NIOSH Carcinogen Classification and Target Risk...

    Science.gov (United States)

    2013-11-15

    .... Place: Surface Transportation Board Hearing Room, Patriots Plaza One, 395 E Street SW., 1st Floor, Room... sufficient evidence from animal data'' meet the criteria for GHS Carcinogen Category 1B. Chemicals...

  13. Application of the two-stage clonal expansion model in characterizing the joint effect of exposure to two carcinogens

    International Nuclear Information System (INIS)

    In this paper, we describe application of the two-stage clonal expansion model to characterize the joint effect of exposure to two carcinogens. This biologically based model of carcinogenesis provides a useful framework for the quantitative description of carcinogenic risks and for defining agents that act as initiators, promoters, and completers. Depending on the mechanism of action, the agent-specific relative risk following exposure to two carcinogens can be additive, multiplicative, or supramultiplicative, with supra-additive relative risk indicating a synergistic effect between the two agents. Maximum-likelihood methods for fitting the two-stage clonal expansion model with intermittent exposure to two carcinogens are described and illustrated, using data on lung-cancer mortality among Colorado uranium miners exposed to both radon and tobacco smoke

  14. NANOSTRUCTURED POROUS SILICON AND LUMINESCENT POLYSILOLES AS CHEMICAL SENSORS FOR CARCINOGENIC CHROMIUM(VI) AND ARSENIC(V)

    Science.gov (United States)

    The chief goal is to develop new selective solid state sensors for carcinogenic and toxic chromium(VI) and arsenic(V) in water based on redox quenching of the luminescence from nanostructured porous silicon and polysiloles.

  15. The International Agency for Research on Cancer (IARC) evaluation of the carcinogenicity of outdoor air pollution: focus on China

    OpenAIRE

    Dana Loomis; Wei Huang; Guosheng Chen

    2014-01-01

    The International Agency for Research on Cancer (IARC) has classified outdoor air pollution and the particulate matter (PM) in outdoor air pollution as carcinogenic to humans, as based on sufficient evidence of carcinogenicity in humans and experimental animals and strong support by mechanistic studies. The data with important contributions to the evaluation are reviewed, highlighting the data with particular relevance to China, and implications of the evaluation with respect to China are dis...

  16. Prediction of rodent carcinogenicity of further 30 chemicals bioassayed by the U.S. National Toxicology Program.

    OpenAIRE

    Benigni, R; Andreoli, C; Zito, R

    1996-01-01

    Recently the U.S. National Toxicology Program (NTP) sponsored a comparative exercise in which different prediction approaches (both biologically and chemically based) were challenged for their predictive abilities of rodent carcinogenicity of a common set of chemicals. The exercise enjoyed remarkable scientific success and stimulated NTP to sponsor a second challenging round of tests, inviting participants to present predictions relative to the rodent carcinogenicity of a further 30 chemicals...

  17. Red meat intake, doneness, polymorphisms in genes that encode carcinogen-metabolizing enzymes and colorectal cancer risk

    OpenAIRE

    Cotterchio, Michelle; Boucher, Beatrice A.; Manno, Michael; Gallinger, Steven; Okey, Allan B; Harper, Patricia A.

    2008-01-01

    Colorectal cancer literature regarding the interaction between polymorphisms in carcinogen-metabolizing enzymes and red meat intake/doneness is inconsistent. A case-control study was conducted to evaluate the interaction between red meat consumption, doneness and polymorphisms in carcinogen-metabolizing enzymes. Colorectal cancer cases diagnosed 1997-2000, aged 20-74 years, were identified through the population-based Ontario Cancer Registry and recruited by the Ontario Family Colorectal Canc...

  18. Liver fatty acid-binding protein: specific mediator of the mitogenesis induced by two classes of carcinogenic peroxisome proliferators.

    OpenAIRE

    S H Khan; Sorof, S

    1994-01-01

    Peroxisome proliferators (PP) are a diverse group of chemicals that induce dramatic increases in peroxisomes in rodent hepatocytes, followed by hypertrophy, hepatomegaly, alterations in lipid metabolism, mitogenesis, and finally hepatocarcinomas. Termed nongenotoxic carcinogens, they do not interact with DNA, are not mutagenic in bacterial assays, and fail to elicit many of the phenotypes associated with classic genotoxic carcinogens. We report here that the mitogenesis induced by the major P...

  19. The metabolic N-oxidation of carcinogenic arylamines in relation to nitrogen charge density and oxidation potential.

    OpenAIRE

    Kadlubar, F F; Fu, P P; Jung, H.; Shaikh, A U; Beland, F A

    1990-01-01

    The N-oxidation of carcinogenic arylamines to form N-hydroxy arylamines has long been regarded as a necessary metabolic step for conversion to proximate carcinogenic derivatives. In contrast, arylamine ring-oxidation has been generally considered to be an important detoxification mechanism. Both enzymatic reactions are carried out in the liver and usually involve the cytochrome P-450 monooxygenases. Studies on the metabolic oxidation of certain arylamines have indicated that the relative char...

  20. Ultrastructure and biochemistry of the light-emitting system of lantern shark (Etmopterus spinax) photophores

    OpenAIRE

    Renwart, Marie

    2014-01-01

    Bioluminescence, i.e. the ability for living organisms to emit light, is a widespread phenomenon in deep-ocean, due to valuable ecological advantages it provides to organisms endowed with this capability. Six percent of deep-sea cartilaginous fishes (sharks, rays, skates and chimaeras) are luminous. Among them, the lantern shark Etmopterus spinax Linnaeus, 1758 is one of the most commons and can be easily caught. For this reason, it has recently become a model species for studying bioluminesc...

  1. Species-specific Toxicity of Aristolochic Acid (AA) in vitro

    OpenAIRE

    Huljic, Susanne; Bruske, Ellen Inga; Pfitzenmaier, Norbert; O'Brien, Evelyn; Dietrich, Daniel R

    2008-01-01

    Differences in toxicity and carcinogenicity of the nephrotoxic compound aristolochic acid between rodents and humans suggest a species-dependent mechanism of action. The goal of this study was to investigate constitutive differences in the susceptibility of renal cortex cells originating from human, rat and porcine origin in vitro. Effects of 24 and 48 h AA exposure on cell number and MTT reduction were studied. Furthermore, using the effective concentrations causing 20 and 50 % reduction (ce...

  2. Nitro Polycyclic Aromatic Hydrocarbons in Particulate Matter Emitted by the Combustion of Diesel and Biodiesel

    Science.gov (United States)

    Valle-Hernández, B. L.; Amador-Muñoz, O.; Jazcilevich, A. D.; Santos-Medina, G. L.; Hernández-Lopéz, E.; Villalobos-Pietrini, R.

    2013-05-01

    The rapid population growth in large urban areas, has resulted in a precipitous increase in the consumption of fossil fuels, mainly by the transport sector, diesel vehicles are a significant source of air pollution by particulate matter emissions, damaging the population health, because of the size and composition of these particles, as they may contain carcinogenic organic compounds such as polycyclic aromatic hydrocarbons and their derivatives, nitro-PAH. This study focused on analysis of nitro-PAH contained in particles emitted from diesel engines fuelled with biodiesel blends (B5, B10 and B16.67) to different driving cycles (rpm and torque), and to compare their concentrations with emissions from current diesel. A diesel truck engine was used in the laboratory for collect particulate mass emitted directly from the exhaust. Mass of particles and nitro-PAH were determined by gas chromatography-mass spectrometry using negative chemical ionization. No reduction was observed in the particles mass per second by using biodiesel relative to diesel (p > 0.1). Seven nitro-PAH were observed in samples: 1-nitronaphthalene, 2-nitronaphthalene, 9-nitroanthracene, 3-nitrophenanthrene, 1,8-dinitronaphthalene, 1-nitropyrene and 1,6-dinitropyrene. 1-nitropyrene showed the highest mass concentration in diesel and in all blends of biodiesel, followed by 3-nitrophenanthrene. Emissions reduction in biodiesel combustion with respect to diesel combustion were observed for 1-nitropyrene: 50 %, in all blends (B5, B10 and B16.67) and for 3-nitrophenanthrene: 55 % in B5, 72 % in B10 and 64 % in B16.67.

  3. Detection of strand breaks in phiX 174 RFI and PM2 DNA reacted with ultimate and proximate carcinogens.

    Science.gov (United States)

    Thielmann, H W

    1977-10-01

    Supercoiled DNA duplexes of phages phiX 174 and PM2 were treated in aqueous solution at neutral pH with ultimate and proximate carcinogens. Subsequently, the carcinogen-treated phage DNAs were subjected to velocity sedimentation in neutral and alkaline sucrose to quantitative introduction of single strand breaks. Reaction of phage DNA with the ultimate carcinogens N-methyl-N-nitrosourea (MeNOUr), N-ethyl-N-nitrosourea (EtNOUr), 7-bromomethyl-benza[a]-anthracene, N-acetoxy-2-acetylaminofluorene [(Ac)2ONFln] and K-region oxides for short periods followed by sedimentation in neutral sucrose gradients led to very few breaks. Incubation with the proximate carcinogens N-hydroxy-2-acetylaminofluorene, 2-acetylaminofluorene, 7-methyl-, and 7,12-dimethyl-benza[a]anthracene did not result in breaks. However, when the phage DNAs were reacted with the ultimate carcinogens under the same conditions but subsequently alkali-denatured and sedimented in alkaline sucrose gradients, single strand breaks were readily introduced. Incubation with the proximate carcinogens followed by alkali denaturation and sedimentation in alkaline sucrose showed that only 7,12-dimethyl-benz[a]anthracene and, to a minor extent, 7-methyl-benz[]anthracene caused alkali-inducible breaks. The ability of N-methyl-N'-nitro-N-nitrosoguanidine to effect breakdown of superhelical phage DNA in alkali was found enhanced in the presence of N-acetyl-cysteine. PMID:145749

  4. Results of screening NCI/NTP nongenotoxic carcinogens and genotoxic noncarcinogens with the k sub e test

    Energy Technology Data Exchange (ETDEWEB)

    Mendelsohn, M.L. (ed.); 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.

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

    Science.gov (United States)

    Leadon, S A

    1987-06-01

    In order to understand the role in carcinogenesis of damage indirectly induced by chemical carcinogens, it is important to identify the primary DNA lesions. We have measured the formation and repair of one type of DNA modification, 5,6-dihydroxydihydrothymine (thymine glycol), following exposure of cultured human cells to the carcinogens N-hydroxy-2-naphthylamine or benzo(a)pyrene. The efficiency of production of thymine glycols in DNA by these carcinogens was compared to that by ionizing radiation and ultraviolet light. Thymine glycols were detected using a monoclonal antibody against this product in a sensitive immunoassay. We found that thymine glycols were produced in DNA in a dose dependent manner after exposure to the carcinogens and that their production was reduced if either catalase or superoxide dismutase or both were present at the time of treatment. The efficiency of thymine glycol production following exposure to the chemical carcinogens was greater than that following equi-toxic doses of radiation. Thymine glycols were efficiently removed from the DNA of human cells following treatment with either the chemical carcinogens, ionizing radiation or ultraviolet light. PMID:3477281

  6. Combining QSAR Modeling and Text-Mining Techniques to Link Chemical Structures and Carcinogenic Modes of Action

    Science.gov (United States)

    Papamokos, George; Silins, Ilona

    2016-01-01

    There is an increasing need for new reliable non-animal based methods to predict and test toxicity of chemicals. Quantitative structure-activity relationship (QSAR), a computer-based method linking chemical structures with biological activities, is used in predictive toxicology. In this study, we tested the approach to combine QSAR data with literature profiles of carcinogenic modes of action automatically generated by a text-mining tool. The aim was to generate data patterns to identify associations between chemical structures and biological mechanisms related to carcinogenesis. Using these two methods, individually and combined, we evaluated 96 rat carcinogens of the hematopoietic system, liver, lung, and skin. We found that skin and lung rat carcinogens were mainly mutagenic, while the group of carcinogens affecting the hematopoietic system and the liver also included a large proportion of non-mutagens. The automatic literature analysis showed that mutagenicity was a frequently reported endpoint in the literature of these carcinogens, however, less common endpoints such as immunosuppression and hormonal receptor-mediated effects were also found in connection with some of the carcinogens, results of potential importance for certain target organs. The combined approach, using QSAR and text-mining techniques, could be useful for identifying more detailed information on biological mechanisms and the relation with chemical structures. The method can be particularly useful in increasing the understanding of structure and activity relationships for non-mutagens.

  7. Laminated active matrix organic light-emitting devices

    Science.gov (United States)

    Liu, Hongyu; Sun, Runguang

    2008-02-01

    Laminated active matrix organic light-emitting device (AMOLED) realizing top emission by using bottom-emitting organic light-emitting diode (OLED) structure was proposed. The multilayer structure of OLED deposited in the conventional sequence is not on the thin film transistor (TFT) backplane but on the OLED plane. The contact between the indium tin oxide (ITO) electrode of TFT backplane and metal cathode of OLED plane is implemented by using transfer electrode. The stringent pixel design for aperture ratio of the bottom-emitting AMOLED, as well as special technology for the top ITO electrode of top-emitting AMOLED, is unnecessary in the laminated AMOLED.

  8. Toxicity of inhaled beta-emitting radionuclides: an experimental approach

    International Nuclear Information System (INIS)

    An experimental approach to evaluation of the toxicity of inhaled beta-emitting radionuclides in laboratory animals is described. These radionuclides are being studied in both relatively soluble (90SrCl2, 144CeCl3, 91YCl3 or 137CsCl) and relatively insoluble aerosol forms (90Y, 91Y, 144Ce or 90Sr in fused aluminosilicate particles). Initial lung or whole-body radionuclide burdens were selected to result in early deaths due to severe lesions at the highest exposure levels, and more subtle changes, such as neoplasia, at the lower levels. The organs affected vary depending on the solubility and chemical characteristics of the isotope. For radionuclides inhaled in relatively soluble forms, long-term effects have been seen in the liver, skeleton, respiratory tract and other tissues. In contrast, long-term effects seen in the dogs exposed to relatively insoluble forms have been mainly associated with the lung and contiguous tissues. In all experiments, emphasis is placed on an evaluation of the influence of radiation dose rate and total dose on the resulting dose-response relationship. Over the mid-range of exposure levels, it will be possible to compare the radiation dose and biological response relationships for the several radioactive aerosols with their different radiation dose patterns. These studies with young adult dogs are complemented with comparable studies in other species (mice, rats and Syrian hamsters) and with animals of different ages (immature, aged). This basic approach, with emphasis on factors that alter the resulting radiation dose pattern, offers the maximum likelihood of meeting the continuing, and not always predictable, needs for information on the toxicity of inhaled beta-emitting radionuclides that may be encountered in nuclear industry operations

  9. Toxicity of inhaled beta-emitting radionuclides: an experimental approach

    International Nuclear Information System (INIS)

    An experimental approach to evaluation of the toxicity of inhaled beta-emitting radionuclides in experimental animals is described. Graded levels of these radionuclides are being studied in both relatively soluble (90SrCl2, 144CeCl3, 91YCl3, 137CsCl) and relatively insoluble forms (90Y, 91Y, 144Ce and 90Sr in fused clay particles). Initial lung or whole-body activity burdens were selected to result in early deaths due to severe lesions at the highest levels, deaths at later times with moderate to marked pathologic changes and more subtle changes such as neoplasia at the lower levels. The organs affected vary depending on the solubility and chemical characteristics of the isotope. For radionuclides inhaled in relatively soluble forms, long-term effects have been seen in the liver, skeleton, and other tissues in addition to some pulmonary effects. In contrast, long-term effects seen in the dogs exposed to relatively insoluble forms have been mainly associated with the lung and contiguous tissues. In the latter experiments, emphasis is placed on an evaluation of the influence of radiation dose rate and total dose on the resulting dose-response relationship. Over the mid-range of the relationship between radiation dose and biological response, it will be possible to compare the relationships for the several radioactive aerosols with their different radiation dose patterns. These studies with young adult dogs are complemented with comparable studies in other species (mice, Syrian hamsters) and with animals of different ages (immature, aged). This basic approach, with emphasis on factors that alter the resulting radiation dose pattern, offers the maximum likelihood of meeting the continuing, and not always predictable, needs for information on the toxicity of inhaled beta-emitting radionuclides that may be encountered in nuclear industry operations. (U.S.)

  10. Alpha Emitting Radionuclides and Radiopharmaceuticals for Therapy

    International Nuclear Information System (INIS)

    Today, cancer treatments mainly rely on surgery or external beam radiation to remove or destroy bulky tumors. Chemotherapy is given when tumours cannot be removed or when dissemination is suspected. However, these approaches cannot permanently treat all cancers and relapse occurs in up to 50% of the patients’ population. Radioimmunotherapy (RIT) and peptide receptor radionuclide therapy (PRRT) are effective against some disseminated and metastatic diseases, although they are rarely curative. Most preclinical and clinical developments in this field have involved electron-emitting radionuclides, particularly iodine-131, yttrium-90 and lutetium-177. The large range of the electrons emitted by these radionuclides reduces their efficacy against very small tumour cell clusters or isolated tumour cells present in residual disease and in many haematological tumours (leukaemia, myeloma). The range of alpha particles in biological tissues is very short, less than 0.1 mm, which makes alpha emitters theoretically ideal for treatment of such isolated tumour cells or micro-clusters of malignant cells. Thus, over the last decade, a growing interest for the use of alpha-emitting radionuclides has emerged. Research on targeted alpha therapy (TAT) began years ago in Nantes through cooperation between Subatech, a nuclear physics laboratory, CRCNA, a cancer research centre with a nuclear oncology team and ITU (Karlsruhe, Germany). CD138 was demonstrated as a potential target antigen for Multiple Myeloma, which is a target of huge clinical interest particularly suited for TAT because of the disseminated nature of the disease consisting primarily of isolated cells and small clusters of tumour cells mainly localized in the bone marrow. Thus anti-CD138 antibodies were labelled with bismuth-213 from actinium-225/bismuth-213 generators provided by ITU and used to target multiple myeloma cells. In vitro studies showed cell cycle arrest, synergism with chemotherapy and very little induction

  11. Nanoengineering of organic light-emitting diodes

    International Nuclear Information System (INIS)

    This thesis reports nanoengineerging of the emission and transport properties of organic light-emitting diodes (LEDs). This is achieved by a control of the electronic material properties and the photonic device properties. A novel class of conjugated materials for electroluminescence (EL) applications is presented, based on successively branching, or dendritic, materials comprising an emissive core and a shielding dendritic architecture. Exciton localisation at the centre of these dendrimers is observed in both luminescence and absorption. A detailed quantum chemical investigation using an exciton model supports these findings and accurately describes the energies and oscillator strengths of transitions in the core and branches. The dendrimer generation describes the degree of branching and gives a direct measure of the separation and interaction between chromophores. Increasing generation is found to lead to a reduction in red tail emission. This correlates with an increase in operating field and LED efficiency. Dendrimer blends with triplet harvesting dendritic phosphors are also investigated and found to exhibit unique emission properties. A numerical device model is presented, which is used to describe the temperature dependence of single layer polymer LEDs by fitting the field-dependent mobility and the barrier to hole injection. The device model is also used to obtain mobility values for the dendrimer materials, which are in excellent agreement with results obtained from time-of-flight measurements. The dendrimer generation is shown to provide a direct control of hopping mobility, which decreases by two orders of magnitude as the dendrimer generation increases from 0 to 3. The photonic properties and spontaneous emission of an LED are modified by incorporating a periodic wavelength scale microstructure into the emitting film. This is found to double the amount of light emitted with no effect on the device current. An investigation of the angular dependence

  12. A micrometer-size movable light emitting area in a resonant tunneling light emitting diode

    International Nuclear Information System (INIS)

    We report on the fabrication of a micrometer-size movable light emitting area in a GaAs/AlAs quantum well resonant tunneling p-i-n diode. The spatial position of the micrometer-size light emitting area shifts linearly with increasing applied bias, up to 30 μm for a bias increment of 0.2 V. Also, the simultaneous resonant tunneling injection of both electrons and holes into the quantum well states is achieved at specific positions of the diode, thus resulting in a tenfold increase of the electroluminescence intensity

  13. A micrometer-size movable light emitting area in a resonant tunneling light emitting diode

    Energy Technology Data Exchange (ETDEWEB)

    Pettinari, G., E-mail: giorgio.pettinari@cnr.it [School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD (United Kingdom); National Research Council (CNR), Institute for Photonics and Nanotechnologies (IFN-CNR), Via Cineto Romano 42, 00156 Roma (Italy); Balakrishnan, N.; Makarovsky, O.; Campion, R. P.; Patanè, A. [School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD (United Kingdom); Polimeni, A.; Capizzi, M. [CNISM-Dipartimento di Fisica, Sapienza Università di Roma, P.le A. Moro 2, 00185 Roma (Italy)

    2013-12-09

    We report on the fabrication of a micrometer-size movable light emitting area in a GaAs/AlAs quantum well resonant tunneling p-i-n diode. The spatial position of the micrometer-size light emitting area shifts linearly with increasing applied bias, up to 30 μm for a bias increment of 0.2 V. Also, the simultaneous resonant tunneling injection of both electrons and holes into the quantum well states is achieved at specific positions of the diode, thus resulting in a tenfold increase of the electroluminescence intensity.

  14. A micrometer-size movable light emitting area in a resonant tunneling light emitting diode

    Science.gov (United States)

    Pettinari, G.; Balakrishnan, N.; Makarovsky, O.; Campion, R. P.; Polimeni, A.; Capizzi, M.; Patanè, A.

    2013-12-01

    We report on the fabrication of a micrometer-size movable light emitting area in a GaAs/AlAs quantum well resonant tunneling p-i-n diode. The spatial position of the micrometer-size light emitting area shifts linearly with increasing applied bias, up to 30 μm for a bias increment of 0.2 V. Also, the simultaneous resonant tunneling injection of both electrons and holes into the quantum well states is achieved at specific positions of the diode, thus resulting in a tenfold increase of the electroluminescence intensity.

  15. Aero particles characterization emitted by mobile sources

    International Nuclear Information System (INIS)

    In our country, the mobile sources that conform most of the emissions at the atmosphere, are concentrated on the urban areas. For the present work, samples coming from the escapes of terrestrial transport were obtained, such as: passenger buses, load transport and particular vehicles of the Metropolitan area of the Toluca valley. The material was analyzed by means of scanning electron microscopy of low vacuum and X-ray diffraction. The objective was to characterize the emitted particles by mobile sources, morphological and chemically to know the structure, size and elements that compose them. (Author)

  16. Efficient organic light emitting-diodes (OLEDs)

    CERN Document Server

    Chang, Yi-Lu

    2015-01-01

    Following two decades of intense research globally, the organic light-emitting diode (OLED) has steadily emerged as the ultimate display technology of choice for the coming decades. Portable active matrix OLED displays have already become prevalent, and even large-sized ultra-high definition 4K TVs are being mass-produced. More exotic applications such as wearable displays have been commercialized recently. With the burgeoning success in displays, researchers are actively bringing the technology forward into the exciting solid-state lighting market. This book presents the knowledge needed for

  17. Investigations of blue emitting phosphors for thermometry

    Science.gov (United States)

    Särner, Gustaf; Richter, Mattias; Aldén, Marcus

    2008-12-01

    Blue emitting phosphors are investigated and reported for possible use in thermometry. Currently reported thermographic phosphors in general have the drawback of long emission lifetimes obstructing the possibility to time gate for background discrimination. An additional problem is that many thermographic phosphors have emission in the red spectral region, making them vulnerable for black body radiation at high temperatures. This work reports the temperature sensitivity for nine phosphors considered suitable for accurate temperature measurements in harsh conditions both in single points and in two dimensions (2D).

  18. Studies of outward-emitting coaxial vircator

    International Nuclear Information System (INIS)

    As a novel concept of vircator geometry proposed, the outward-emitting coaxial vircator (OECV) is at the cutting edge in the field of high-power microwave (HPM) source researches. Theoretical analyses are carried out to study the space-charge-limiting current in coaxial configuration and the terms of virtual cathode formation. According to the simulation results, OECV has the advantages in energy conversion efficiency and bears the potentialities in increasing the high-power microwave pulse width, as well as in generating HPM in relatively low bands. Two kinds of geometries for HPM emission are also given

  19. Prediction of rodent carcinogenic potential of naturally occurring chemicals in the human diet using high-throughput QSAR predictive modeling

    International Nuclear Information System (INIS)

    Consistent with the U.S. Food and Drug Administration (FDA) Critical Path Initiative, predictive toxicology software programs employing quantitative structure-activity relationship (QSAR) models are currently under evaluation for regulatory risk assessment and scientific decision support for highly sensitive endpoints such as carcinogenicity, mutagenicity and reproductive toxicity. At the FDA's Center for Food Safety and Applied Nutrition's Office of Food Additive Safety and the Center for Drug Evaluation and Research's Informatics and Computational Safety Analysis Staff (ICSAS), the use of computational SAR tools for both qualitative and quantitative risk assessment applications are being developed and evaluated. One tool of current interest is MDL-QSAR predictive discriminant analysis modeling of rodent carcinogenicity, which has been previously evaluated for pharmaceutical applications by the FDA ICSAS. The study described in this paper aims to evaluate the utility of this software to estimate the carcinogenic potential of small, organic, naturally occurring chemicals found in the human diet. In addition, a group of 19 known synthetic dietary constituents that were positive in rodent carcinogenicity studies served as a control group. In the test group of naturally occurring chemicals, 101 were found to be suitable for predictive modeling using this software's discriminant analysis modeling approach. Predictions performed on these compounds were compared to published experimental evidence of each compound's carcinogenic potential. Experimental evidence included relevant toxicological studies such as rodent cancer bioassays, rodent anti-carcinogenicity studies, genotoxic studies, and the presence of chemical structural alerts. Statistical indices of predictive performance were calculated to assess the utility of the predictive modeling method. Results revealed good predictive performance using this software's rodent carcinogenicity module of over 1200 chemicals

  20. Organic bistable light-emitting devices

    Science.gov (United States)

    Ma, Liping; Liu, Jie; Pyo, Seungmoon; Yang, Yang

    2002-01-01

    An organic bistable device, with a unique trilayer structure consisting of organic/metal/organic sandwiched between two outmost metal electrodes, has been invented. [Y. Yang, L. P. Ma, and J. Liu, U.S. Patent Pending, U.S. 01/17206 (2001)]. When the device is biased with voltages beyond a critical value (for example 3 V), the device suddenly switches from a high-impedance state to a low-impedance state, with a difference in injection current of more than 6 orders of magnitude. When the device is switched to the low-impedance state, it remains in that state even when the power is off. (This is called "nonvolatile" phenomenon in memory devices.) The high-impedance state can be recovered by applying a reverse bias; therefore, this bistable device is ideal for memory applications. In order to increase the data read-out rate of this type of memory device, a regular polymer light-emitting diode has been integrated with the organic bistable device, such that it can be read out optically. These features make the organic bistable light-emitting device a promising candidate for several applications, such as digital memories, opto-electronic books, and recordable papers.

  1. White organic light-emitting diodes with an ultra-thin premixed emitting layer

    CERN Document Server

    Jeon, T; Tondelier, Denis; Bonnassieux, Yvan; Forget, Sebastien; Chenais, Sebastien; Ishow, Elena

    2014-01-01

    We described an approach to achieve fine color control of fluorescent White Organic Light-Emitting Diodes (OLED), based on an Ultra-thin Premixed emitting Layer (UPL). The UPL consists of a mixture of two dyes (red-emitting 4-di(4'-tert-butylbiphenyl-4-yl)amino-4'-dicyanovinylbenzene or fvin and green-emitting 4-di(4'-tert-butylbiphenyl-4-yl)aminobenzaldehyde or fcho) premixed in a single evaporation cell: since these two molecules have comparable structures and similar melting temperatures, a blend can be evaporated, giving rise to thin films of identical and reproducible composition compared to those of the pre-mixture. The principle of fine color tuning is demonstrated by evaporating a 1-nm-thick layer of this blend within the hole-transport layer (4,4'-bis[N-(1-naphtyl)-N-phenylamino]biphenyl (\\alpha-NPB)) of a standard fluorescent OLED structure. Upon playing on the position of the UPL inside the hole-transport layer, as well as on the premix composition, two independent parameters are available to finel...

  2. Rigorous simulations of emitting and non-emitting nano-optical structures

    NARCIS (Netherlands)

    Janssen, O.T.A.

    2010-01-01

    In the next decade, several applications of nanotechnology will change our lives. LED lighting is about to replace the common light bulb. The main advantages are its energy efficiency and long lifetime. LEDs can be much more efficient, when part of the emitted light that is currently trapped in the

  3. NICKEL SPECIES EMISSION INVENTORY FOR OIL-FIRED BOILERS

    Energy Technology Data Exchange (ETDEWEB)

    Kevin C. Galbreath; Richard L. Schulz; Donald L. Toman; Carolyn M. Nyberg

    2004-01-01

    Representative duplicate fly ash samples were obtained from the stacks of 400-MW and 385-MW utility boilers (Unit A and Unit B, respectively) using a modified U.S. Environmental Protection Agency (EPA) Method 17 sampling train assembly as they burned .0.9 and 0.3 wt% S residual oils, respectively, during routine power plant operations. Residual oil fly ash (ROFA) samples were analyzed for nickel (Ni) concentrations and speciation using inductively coupled plasma-atomic emission spectroscopy, x-ray absorption fine structure (XAFS) spectroscopy, x-ray diffraction (XRD), and a water-soluble Ni extraction method. ROFA water extraction residues were also analyzed for Ni speciation using XAFS and XRD. Total Ni concentrations in the ROFAs were similar, ranging from 1.3 to 1.5 wt%; however, stack gas Ni concentrations in the Unit A were {approx}990 {micro}g/Nm{sup 3} compared to {approx}620 {micro}g/Nm{sup 3} for Unit B because of the greater residual oil feed rates employed at Unit A to attain higher load (i.e., MW) conditions with a lower heating value oil. Ni speciation analysis results indicate that ROFAs from Unit A contain about 3 wt% NiSO{sub 4} {center_dot} xH{sub 2}O (where x is assumed to be 6 for calculation purposes) and a Ni-containing spinel compound, similar in composition to (Mg,Ni)(Al,Fe){sub 2}O{sub 4}. ROFAs from Unit B contain on average 2.0 wt% NiSO{sub 4} {center_dot} 6H{sub 2}O and 1.1 wt% NiO. XAFS and XRD analyses did not detect any nickel sulfide compounds, including nickel subsulfide (Ni{sub 3}S{sub 2}) (XAFS detection limit is 5% of the total Ni concentration). In addition, XAFS measurements indicated that inorganic sulfate and organic thiophene species account for >97% of the total sulfur in the ROFAs. The presence of NiSO{sub 4} {center_dot} xH{sub 2}O and nickel oxide compound mixtures and lack of carcinogenic Ni{sub 3}S{sub 2} or nickel sulfide compounds (e.g., NiS, NiS{sub 2}) in ROFAs stack-sampled from 400- and 385-MW boilers are contrary

  4. 槟榔致癌物质与口腔癌%Areca nut-related carcinogens and oral cancer

    Institute of Scientific and Technical Information of China (English)

    黄龙; 翦新春

    2014-01-01

    Areca nut is a recently confirmed classⅠcarcinogen. The areca nut chewing habit is a primary environmental risk factor for the development of oral cancer due to cytotoxicity, genotoxicity, mutagenicity, and carcinogenicity of arecoline(ARC), areca-containing tannins, areca-specific nitrosamine(ASNA), and reactive oxygen species(ROS) produced during areca nut chewing. ARC is capable of inducing apoptosis of oral fibroblasts, keratinocytes, and human umbilical vein endothelial cells. The results of different types of short-term screening tests differ, so the genotoxicity and mutagenicity of areca-containing tannins remain controversial. Tannin-containing polyphenolic fraction is a primary carcinogenic ingredient. 3-Methyl-nitrosamino propionaldehyde can induce DNA strand breakage and DNA-protein cross-linkage for human buccal keratinocytes. 3-Methyl-nitrosamino propionitrile is a potent carcinogen that can induce nasal, esophageal, and tongue tumors in laboratory animals. ROS produced during areca nut chewing can promote tumorigenesis by inducing DNA oxidative damage and activating oncogenes. A newly found proteoglycan in the 3.0×104 to 10.0× 104 relative molecular mass fraction of areca nut extract induces oxidative stress and modulates a signaling cascade that upregulates hypoxia, inducing factor-1α expression in oral cancer cells, which eventually leads to autophagy. Autophagy can help cancer cells survive ARC-induced apoptosis and promote the development of oral cancer. Areca nut extract can enhance tongue cancer cell-induced platelet aggregation by generating ROS, thus promoting tongue cancer metastasis.%槟榔为一级致癌物,咀嚼槟榔引起口腔癌缘于槟榔中的槟榔碱(ARC)、槟榔鞣质、槟榔特异性亚硝胺(ASNA)和活性氧(ROS)等具有细胞毒性、遗传毒性、致突变性和致癌性。ARC可诱导口腔成纤维细胞、角质形成细胞和人脐静脉内皮细胞程序性死亡。槟榔鞣质有否遗传毒性

  5. The function and significance of SELENBP1 downregulation in human bronchial epithelial carcinogenic process.

    Directory of Open Access Journals (Sweden)

    Gu-Qing Zeng

    Full Text Available BACKGROUND: Our quantitative proteomic study showed that selenium-binding protein 1 (SELENBP1 was progressively decreased in human bronchial epithelial carcinogenic process. However, there is little information on expression and function of SELENBP1 during human lung squamous cell cancer (LSCC carcinogenesis. METHODS: iTRAQ-tagging combined with 2D LC-MS/MS analysis was used to identify differentially expressed proteins in the human bronchial epithelial carcinogenic process. SELENBP1, member of selenoproteins family and progressively downregulated in this process, was selected to further study. Both Western blotting and immunohistochemistry were performed to detect SELENBP1 expression in independent sets of tissues of bronchial epithelial carcinogenesis, and ability of SELENBP1 for discriminating NBE (normal bronchial epithelium from preneoplastic lesions from invasive LSCC was evaluated. The effects of SELENBP1 downregulation on the susceptibility of benzo(apyrene (B[a]P-induced human bronchial epithelial cell transformation were determined. RESULTS: 102 differentially expressed proteins were identified by quantitative proteomics, and SELENBP1 was found and confirmed being progressively decreased in the human bronchial epithelial carcinogenic process. The sensitivity and specificity of SELENBP1 were 80% and 79% in discriminating NBE from preneoplastic lesions, 79% and 82% in discriminating NBE from invasive LSCC, and 77% and 71% in discriminating preneoplastic lesions from invasive LSCC, respectively. Furthermore, knockdown of SELENBP1 in immortalized human bronchial epithelial cell line 16HBE cells significantly increased the efficiency of B[a]P-induced cell transformation. CONCLUSIONS: The present data shows for the first time that decreased SELENBP1 is an early event in LSCC, increases B[a]P-induced human bronchial epithelial cell transformation, and might serve as a novel potential biomarker for early detection of LSCC.

  6. Carcinogenic potential of soils contaminated with polycyclic aromatic hydrocarbons (PAHs) in Xiamen metropolis, China.

    Science.gov (United States)

    Cai, Chao; Zhang, Youchi; Reid, Brian J; Nunes, Luis M

    2012-12-01

    Xiamen is one of China's most rapidly developing metropolises. The objectives of the present study were: (1) to establish the levels and spatial distribution of polycyclic aromatic hydrocarbons (PAHs) in soil across the Xiamen metropolis, (2) to evaluate the extent to which PAH concentrations were elevated in the high urbanization area (HUA) of the island and how these compared with those in the low urbanization area (LUA) of the mainland, and (3) to evaluate the PAH hazard based upon their Carcinogenic Potential (CP), defined as toxicity equivalence of ∑PAHs. Twenty two alternative relative carcinogenic potency schemes were used and compared. Results demonstrated PAH concentrations to be greatly elevated across the entire metropolis. Significantly, the most enriched compounds represented the greatest concern with respect to carcinogenicity. The CP of more than 25% of the industrial samples from the island surpassed the Canadian guidance threshold value (600 μg kg⁻¹) for an excess lifetime cancer risk (ELCR) of 1 in 10⁻⁶. While soil samples from the remaining land uses on the island were all below this threshold, PAH levels in soil were nonetheless elevated (enrichment factors of between 4.1 ± 1.9 and 16.3 ± 12.4 in the HUA, and between 1.3 ± 0.7 and 10.8 ± 4.4 in the LUA). Results relating to agricultural locations on the island indicated 75% of the samples in HUA and 28% of the samples in LUA to be above the USEPA guidance value for BaP (15 μg kg⁻¹). Given the exceptionally high population density on the island there is a need for further research to evaluate multiple pathway PAH exposure risks. PMID:23092998

  7. Inhibition of DNA synthesis by chemical carcinogens in cultures of initiated and normal proliferating rat hepatocytes

    International Nuclear Information System (INIS)

    Rat hepatocytes in primary culture can be stimulated to replicate under the influence of rat serum and sparse plating conditions. Higher replication rates are induced by serum from two-thirds partially hepatectomized rats. The effects of carcinogens and noncarcinogens on the ability of hepatocytes to synthesize DNA were examined by measuring the incorporation of [3H]thymidine by liquid scintillation counting and autoradiography. Hepatocyte DNA synthesis was not decreased by ethanol or dimethyl sulfoxide at concentrations less than 0.5%. No effect was observed when 0.1 mM ketamine, Nembutal, hypoxanthine, sucrose, ascorbic acid, or benzo(e)pyrene was added to cultures of replicating hepatocytes. Estrogen, testosterone, tryptophan, and vitamin E inhibited DNA synthesis by approximately 50% at 0.1 mM, a concentration at which toxicity was noticeable. Several carcinogens requiring metabolic activation as well as the direct-acting carcinogen N-methyl-N'-nitro-N-nitrosoguanidine interfered with DNA synthesis. Aflatoxin B1 inhibited DNA synthesis by 50% (ID50) at concentrations between 1 X 10(-8) and 1 X 10(-7) M. The ID50 for 2-acetylaminofluorene was between 1 X 10(-7) and 1 X 10(-6) M. Benzo(a)pyrene and 3'-methyl-4-dimethylaminoazobenzene inhibited DNA synthesis 50% between 1 X 10(-5) and 1 X 10(-4) M. Diethylnitrosamine and dimethylnitrosamine (ID50 between 1 X 10(-4) and 5 X 10(-4) M) and 1- and 2-naphthylamine (ID50 between 1 X 10(-5) and 5 X 10(-4) M) caused inhibition of DNA synthesis at concentrations which overlapped with concentrations that caused measurable toxicity

  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. Differences in gene expression profiles in the liver between carcinogenic and non-carcinogenic isomers of compounds given to rats in a 28-day repeat-dose toxicity study.

    Science.gov (United States)

    Nakayama, Koji; Kawano, Yukiko; Kawakami, Yuuki; Moriwaki, Norichika; Sekijima, Masaru; Otsuka, Masanori; Yakabe, Yoshikuni; Miyaura, Hideki; Saito, Koichi; Sumida, Kayo; Shirai, Tomoyuki

    2006-12-15

    Some compounds have structural isomers of which one is apparently carcinogenic, and the other not. Because of the similarity of their chemical structures, comparisons of their effects can allow gene expression elicited in response to the basic skeletons of the isomers to be disregarded. We compared the gene expression profiles of male Fischer 344 rats administered by daily oral gavage up to 28 days using an in-house oligo microarray. 2-Acetylaminofluorene (2-AAF), 2,4-diaminotoluene (2,4-DAT), 2-nitropropane (2-NP), and 2-nitro-p-phenylenediamine (2-NpP) are hepatocarcinogenic. However, their isomers, 4-acetylaminofluorene (4-AAF), 2,6-diaminotoluene (2,6-DAT), 1-nitropropane (1-NP), and 4-nitro-o-phenylenediamine (4-NoP), are non-hepatocarcinogenic. Because of the limited carcinogenicity of 2-NpP, we attempted to perform two-parametric comparison analyses with (1) a set of 4 isomers: 2-AAF, 2,4-DAT, 2-NP, and 2-NpP as "carcinogenic", and 4-AAF, 2,6-DAT, 1-NP, and 4-NoP as "non-carcinogenic"; and (2) a set of 3 isomers: 2-AAF, 2,4-DAT, and 2-NP, as "carcinogenic", and 4-AAF, 2,6-DAT, and 1-NP as "non-carcinogenic". After ratio filtering and Welch's approximate t-test analysis, 54 and 28 genes were selected from comparisons between the sets of 3 and 4 isomers, respectively, for day 28 data. Using hierarchical clustering analysis with the 54 or 28 genes, 2-AAF, 2,4-DAT, and 2-NP clustered into a "carcinogenic" branch. 2-NpP was in the same cluster as 4-NoP and 4-AAF. This clustering corresponded to the previous finding that 2-NpP is not carcinogenic in male Fischer 344 rats, which indicates that comparing the differences in gene expression elicited by different isomers is an effective method of developing a prediction system for carcinogenicity. PMID:17070881

  10. Analysis of carcinogenic mechanisms of liver cancers induced by chronic exposure to alpha-particles from internally deposited Thorotrast

    International Nuclear Information System (INIS)

    For the successful space traveling, the possibility for the detrimental effects on health including cancer caused by exposure to cosmic rays is a major concern. Thorotrast is a 25% colloidal solution of natural α-emitter, thorium dioxide used as a radiological contrast medium during World War II. It caused hepatic malignant tumors by the local exposure to α-particles decades after administration. Thorotrast-induced liver tumors consist of hepatocellular carcinoma (HCC), intrahepatic cholangiocarcinoma (ICC), and angiosarcoma (AS) at nearly the same instance. We analyzed mutations of the p53 and the K-ras genes, microsatellite instability (MSI), and loss of heterozygosity (LOH) in Thorotrast ICC. The major p53 mutation observed in Thorotrast ICC was the transition type, suggesting that reactive oxygen species are not likely involved in gene mutations of Thorotrast cancers. MSI frequency in Thorotrast ICC was significantly higher than that in non-Thorotrast ICC. MSI was partly attributed to the inactivation of the hMLH1 mismatch repair gene via methylation of the promoter region and to monoclonal expansion of cells with mutations. Thorotrast ICC shared LOH pattern with non-Thorotrast HCC and ICC. Furthermore, we could assess the distribution and the quantity of deposited thorium using an imaging plate and a BAS image analyzer. The distribution of thorium deposits was not always consistent with that of apoptotic cells. We conclude that Thorotrast ICC is developed through complex carcinogenic steps including genomic instability and mutations of crucial genes during remodeling of the liver architecture. We emphasize how pathological specimens from Thorotrast patients are valuable for assessing the relevance of long-term exposure to low dose α-particles to radiation carcinogenesis

  11. Tobacco, Microbes, and Carcinogens: Correlation Between Tobacco Cure Conditions, Tobacco-Specific Nitrosamine Content, and Cured Leaf Microbial Community.

    Science.gov (United States)

    Law, Audrey D; Fisher, Colin; Jack, Anne; Moe, Luke A

    2016-07-01

    Tobacco-specific nitrosamines are carcinogenic N-nitrosamine compounds present at very low levels in freshly harvested tobacco leaves that accumulate during leaf curing. Formation of N-nitrosamine compounds is associated with high nitrate levels in the leaf at harvest, and nitrate is presumed to be the source from which the N-nitrosation species originates. More specifically, nitrite is considered to be a direct precursor, and nitrite is linked with N-nitrosation in many environmental matrices where it occurs via microbial nitrate reduction. Here, we initiate work exploring the role of leaf microbial communities in formation of tobacco-specific nitrosamines. Leaves from burley tobacco line TN90H were air cured under various temperature and relative humidity levels, and 22 cured tobacco samples were analyzed for their microbial communities and leaf chemistry. Analysis of nitrate, nitrite, and total tobacco-specific nitrosamine levels revealed a strong positive correlation between the three variables, as well as a strong positive correlation with increasing relative humidity during cure conditions. 16S rRNA gene amplicon sequencing was used to assess microbial communities in each of the samples. In most samples, Proteobacteria predominated at the phylum level, accounting for >90 % of the OTUs. However, a distinct shift was noted among members of the high tobacco-specific nitrosamine group, with increases in Firmicutes and Actinobacteria. Several OTUs were identified that correlate strongly (positive and negative) with tobacco-specific nitrosamine content. Copy number of bacterial nitrate reductase genes, obtained using quantitative PCR, did not correlate strongly with tobacco-specific nitrosamine content. Incomplete denitrification is potentially implicated in tobacco-specific nitrosamine levels. PMID:27023797

  12. Mechanisms of immunosuppression induced in mice by orthoaminoazotoluene and its non-carcinogenic analogue

    International Nuclear Information System (INIS)

    Single injections of ortho-aminoazotoluene (OAT) or aminoazobenzene (AB) decrease the immune response of DD mice to the strain-nonspecific Krebs-2 tumor. The immunosuppressive action of AB is due to its toxicity for lymphoid cells, whereas the OAT effect is mediated by adrenal glands. After OAT injection, 2-oxycorticosteroids level is elevated although their production by adrenal glands is not increased. The accumulation of glucocorticoids in blood after OAT injection is assumed to be the result of a decreased hormone utilization because of the blockade of receptor proteins or metabolizing enzymes in liver cells by a carcinogen

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

    DEFF Research Database (Denmark)

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

    2013-01-01

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

  14. A theoretical concept of low level/low LET radiation carcinogenic risk (LLCR) projection

    Energy Technology Data Exchange (ETDEWEB)

    Filyushkin, I.V. [Laboratory of Theoretical Radiobiology, Moscow (Russian Federation)

    1992-06-01

    Carcinogenic risk to humans resulting from low level/low LET radiation exposure (LLLCR) has not been observed directly because epidemiological observations have not yet provided statistically significant data on risk values. However, these values are of great interest for radiation health science and radiation protection practice under both normal conditions and emergency situations. This report presents a theoretical contribution to the validation of dose and dose rate efficiency factors (DDREF) transforming cocinogenic risk coefficients from those revealed in A-bomb survivors to factors appropriate for the projection of the risk resulting from very low levels of low LET radiation.

  15. Formation and Human Risk of Carcinogenic Heterocyclic Amines Formed from Natural Precursors in Meat

    Energy Technology Data Exchange (ETDEWEB)

    Knize, M G; Felton, J S

    2004-11-22

    A group of heterocyclic amines that are mutagens and rodent carcinogens form when meat is cooked to medium and well-done states. The precursors of these compounds are natural meat components: creatinine, amino acids and sugars. Defined model systems of dry-heated precursors mimic the amounts and proportions of heterocyclic amines found in meat. Results from model systems and cooking experiments suggest ways to reduce their formation and, thus, to reduce human intake. Human cancer epidemiology studies related to consumption of well-done meat products are listed and compared.

  16. Reproductive and carcinogenic health risks to hospital personnel from chemical exposure--a literature review.

    Science.gov (United States)

    Babich, H

    1985-01-01

    Hospital personnel, both those involved directly (surgeons, anesthesiologists, operating room nurses) and indirectly (pharmacists, laboratory technicians) with promoting the well-being of patients, and those involved in maintaining the proper functioning of the hospital (housekeeping personnel, painters, machinists), may be exposed to chemicals that are potential reproductive and carcinogenic hazards. Waste anesthetic gases, sterilants, such as ethylene oxide and formaldehyde, antineoplastic drugs, methylmethacrylate, asbestos, and various organic reagents and solvents may induce genetic damage, cancer, congenital malformation, still-birth, and spontaneous abortion. PMID:10274220

  17. A theoretical concept of low level/low LET radiation carcinogenic risk (LLCR) projection

    International Nuclear Information System (INIS)

    Carcinogenic risk to humans resulting from low level/low LET radiation exposure (LLLCR) has not been observed directly because epidemiological observations have not yet provided statistically significant data on risk values. However, these values are of great interest for radiation health science and radiation protection practice under both normal conditions and emergency situations. This report presents a theoretical contribution to the validation of dose and dose rate efficiency factors (DDREF) transforming cocinogenic risk coefficients from those revealed in A-bomb survivors to factors appropriate for the projection of the risk resulting from very low levels of low LET radiation

  18. Sorption, degradation and mobility of ptaquiloside, a carcinogenic Bracken (Pteridium sp.) constituent, in the soil environment

    DEFF Research Database (Denmark)

    Rasmussen, Lars Holm; Lauren, Denis; Hansen, Hans Christian Bruun

    2005-01-01

    Ptaquiloside (PTA) is a carcinogenic norsesquiterpene glucoside produced by Bracken in amounts up to at least 13 500 mg m2. The toxin is transferred from Bracken to the underlying soil from where it may leach to surface and groundwaters impairing the quality of drinking water. The objectives of the...... present study were to characterize the solubility, degradation and retention of PTA in soils in order to evaluate the risk for groundwater contamination. PTA was isolated from Bracken. The logarithmic octanol–water and ethyl acetate–water partitioning coefficients for PTA were 0.63 and 0.88, respectively...

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

    DEFF Research Database (Denmark)

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

    2003-01-01

    Bracken (Pteridium aquilinum (L.) Kuhn) is a common fern found on all continents except Antarctica. It is under suspicion of causing cancer among people who utilizes it as food. The main carcinogenic compound is thought to be the water-soluble compound ptaquiloside. Ptaquiloside-uptake may occur...... Bracken-litter, the turnover rate and the size of Bracken-stands determined the ptaquiloside-content in the soil materials while the content in fronds was found to be a function of the frond-height and the light-exposure in the ecosystem....

  20. Trichinella spiralis: Mere Co-Existence or Carcinogenic Parasite For Oral Squamous Cell Carcinoma?

    Science.gov (United States)

    Shirazi, Nadia; Bist, Sampan Singh; Ahmad, Sohaib; Harsh, Meena

    2015-10-01

    Trichinella spiralis is a parasite which is usually seen in pork-eaters. Most of the trichinosis infections cause little or no symptoms. We report a rare case of a middle aged North Indian male who presented with a painless ulcer in right buccal mucosa which was biopsied and reported as squamous cell carcinoma. Wide local excision was done subsequently which showed encysted larvae of Trichinella spiralis in the deeper skeletal muscle bundles. This article supports the carcinogenic potential of trichinosis and suggests timely work-up and treatment of the parasite. PMID:26557527

  1. Preferential binding of growth inhibitory prostaglandins by the target protein of a carcinogen.

    OpenAIRE

    S H Khan; Sorof, S

    1990-01-01

    Liver fatty acid binding protein (L-FABP) is the principal target protein of the hepatic carcinogen N-(2-fluorenyl)acetamide (2-acetylaminofluorene) in rat liver. In addition, the cyclopentenone prostaglandins (PG), PGA, PGJ2, and delta 12-PGJ2, inhibit the growth of many cell types in vitro. This report describes the preferential binding of the growth inhibitory prostaglandins by L-FABP and the reversible inhibition of thymidine incorporation into DNA by PGA2 and delta 12-PGJ2 in primary cul...

  2. Bacterial Metabolism in Humans of the Carcinogen IQ to the Direct Acting Mutagen Hydroxy-IQ

    OpenAIRE

    Van Tassell, R L; Carman, R. J.; Kingston, D. G. I.; Wilkins, T D

    2011-01-01

    7-hydroxy-IQ is the major product of the bacterial metabolism of IQ, a potent dietary carcinogen. Yet, unlike IQ, hydroxy-IQ is directly active in the salmonella/microsomal mutagenicity assay. Two subjects consumed a meal of fried meats containing IQ but no detectable hydroxy-IQ. Hydroxy-IQ was isolated from the subjects’ faeces collected within 30 h following the fried meat meal; it was absent from the subjects’ faeces before and after the meal. This is the first evidence that hy...

  3. Voltammetric Determination of Carcinogenic Air Pollutant 2-Nitrofluorene Using Polished Silver Solid Amalgam Composite Electrode

    Czech Academy of Sciences Publication Activity Database

    Vyskočil, V.; Krejčová, Z.; Daňhel, A.; Navrátil, Tomáš; Barek, J.

    Ústí nad Labem : Best Servis, 2009 - (Barek, J.; Navrátil, T.), s. 123-126 ISBN 978-80-254-3997-5. [Moderní elektrochemické metody /29./. Jet řichovice (CZ), 25.05.2009-29.05.2009] R&D Projects: GA MŠk(CZ) LC06035; GA ČR GA203/07/1195; GA AV ČR IAA400400806 Institutional research plan: CEZ:AV0Z40400503 Keywords : voltammetry * nitrocompounds * detection * carcinogens Subject RIV: CG - Electrochemistry

  4. Near infrared polymer light-emitting diodes

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yong; YANG Jian; HOU Qiong; MO Yueqi; PENG Junbiao; CAO Yong

    2005-01-01

    High efficiency of near infrared polymer light-emitting diodes with bilayer structure was obtained. The diode structure is ITO/PEDOT/L1/L2/Ba/Al, where L1 is phenyl-substituted poly [p-phenylphenylene vinylene] derivative (P-PPV), L2 is 9,9-dioctylfluorene (DOF) and 4,7- bis(3-hexylthiophen)-2-yl-2,1,3-naphthothiadiazole (HDNT) copolymer (PFHDNT10). The electroluminescence (EL) spectrum of diodes from PFHDNT10 is at 750 nm located in the range of near infrared. The maximum external quantum efficiency is up to 2.1% at the current density of 35 mA/cm2. The improvement of the diode's performances was considered to be the irradiative excitons confined in the interface between L1 and L2 layers.

  5. Recycling technology of emitted carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Arakawa, Hironori [National Inst. of Materials and Chemical Research (NIMC), Ibaraki (Japan)

    1993-12-31

    Ways to halt global warming are being discussed worldwide. Global warming is an energy problem which is mainly attributed to the large volumes of carbon dioxide (CO{sub 2}) released into the atmosphere from the rapid increase in energy consumption since the Industrial Revolution. The basic solution to the problem, therefore, is to cut consumption of fossil fuels. To this end, it is important to promote energy conservation by improving the fuel efficiency of machines, as well as shift to energy sources that do not emit carbon dioxide and develop related technologies. If current trends in economic growth continue in the devloping world as well as the developed countries, there can be no doubt that energy consumption will increase. Therefore, alongside energy conservation and the development of alternative energies, the importance of technologies to recover and fix CO{sub 2} will increase in the fight against global warming.

  6. Does antimatter emit a new light ?

    CERN Document Server

    Santilli, R M

    1997-01-01

    We identify a number of problematic aspects of current classical and quantum theories of antimatter; we introduce a new mathematical formalism which is an antiautomorphic image of that of matter equivalent to charge conjugation at the operator level, but applicable from Newton's equations to quantum mechanics; we show that the emerging new theory of antimatter recovers known experimental data on electroweak interactions; we finally identity the following predictions of the theory: 1) reversal in the field of matter of the gravitational curvature (antigravity) for stable antiparticles and their bound states, such as the anti-hydrogen atom; 2) conventional (attractive) gravity for a bound state of an elementary particle and its antiparticle, such as the positronium; and 3) prediction that the anti- hydrogen atom emits a new photon which coincides with the conventional photon for all electroweak interactions but experiences repulsion in the gravitational field of matter.

  7. Ionic liquid polyoxometalates as light emitting materials

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz-acosta, Denisse [Los Alamos National Laboratory; Del Sesto, Rico E [Los Alamos National Laboratory; Scott, Brian [Los Alamos National Laboratory; Bennett, Bryan L [Los Alamos National Laboratory; Purdy, Geraldine M [Los Alamos National Laboratory; Muenchausen, Ross E [Los Alamos National Laboratory; Mc Kigney, Edward [Los Alamos National Laboratory; Gilbertson, Robert [Los Alamos National Laboratory

    2008-01-01

    The low melting point, negligible vapor pressure, good solubility, and thermal and chemical stability make ionic liquids useful materials for a wide variety of applications. Polyoxometalates are early transition metal oxygen clusters that can be synthesized in many different sizes and with a variety of heterometals. The most attractive feature of POMs is that their physical properties, in particular electrical, magnetic, and optical properties, can be easily modified following known procedures. It has been shown that POMs can exhibit cooperative properties, as superconductivity and energy transfer. POM ionic liquids can be obtained by selecting the appropliate cation. Different alkyl ammonium and alkyl phosphonium salts are being used to produce new POM ionic liquids together with organic or inorganic luminescent centers to design light emitting materials. Ammonium and phosphonium cations with activated, polymerizable groups are being used to further polymerize the ionic liquid into transparent, solid materials with high metal density.

  8. Light-Emitting Diodes: A Hidden Treasure

    Science.gov (United States)

    Planinšič, Gorazd; Etkina, Eugenia

    2014-02-01

    LEDs, or light-emitting diodes, are cheap, easy to purchase, and thus commonly used in physics instruction as indicators of electric current or as sources of light (Fig. 1). In our opinion LEDs represent a unique piece of equipment that can be used to collect experimental evidence, and construct and test new ideas in almost every unit of a general physics course (and in many advanced courses) either (I) as "black boxes" that allow students to study certain properties of a system of interest, (II) as physical systems that allow students to learn an astonishing amount of physics that they usually do not encounter in a regular introductory physics course, and (III) as non-traditional devices that allow students to construct concepts that are traditionally a part of a general physics course.

  9. Tunable Ultraviolet Vertically-emitting Organic Laser

    CERN Document Server

    Forget, Sebastien; Diffalah, Nordine; Siove, Alain; Chenais, Sebastien

    2011-01-01

    A solid-state organic thin-film laser with intracavity frequency doubling is reported. Tunable ultraviolet emission from 309 to 322 nm is achieved from a vertical external cavity surface-emitting organic laser, with 2 % efficiency (1 $\\mu$J at 315 nm). The laser comprises a polymethyl(methacrylate) layer doped with Rhodamine 640, spun-cast onto a plane mirror, a remote concave mirror, a nonlinear crystal and a dichroic separator. The output is spectrally narrow (<0.5 nm FWHM) and tunable through phase-matching selection of the fundamental radiation lasing modes. These results highlight a low-cost and portable alternative to tunable UV laser sources, useful for spectroscopic applications.

  10. SUMER: Solar Ultraviolet Measurements of Emitted Radiation

    Science.gov (United States)

    Wilhelm, K.; Axford, W. I.; Curdt, W.; Gabriel, A. H.; Grewing, M.; Huber, M. C. E.; Jordan, M. C. E.; Lemaire, P.; Marsch, E.; Poland, A. I.

    1988-01-01

    The SUMER (solar ultraviolet measurements of emitted radiation) experiment is described. It will study flows, turbulent motions, waves, temperatures and densities of the plasma in the upper atmosphere of the Sun. Structures and events associated with solar magnetic activity will be observed on various spatial and temporal scales. This will contribute to the understanding of coronal heating processes and the solar wind expansion. The instrument will take images of the Sun in EUV (extreme ultra violet) light with high resolution in space, wavelength and time. The spatial resolution and spectral resolving power of the instrument are described. Spectral shifts can be determined with subpixel accuracy. The wavelength range extends from 500 to 1600 angstroms. The integration time can be as short as one second. Line profiles, shifts and broadenings are studied. Ratios of temperature and density sensitive EUV emission lines are established.

  11. A single blue nanorod light emitting diode

    Science.gov (United States)

    Hou, Y.; Bai, J.; Smith, R.; Wang, T.

    2016-05-01

    We report a light emitting diode (LED) consisting of a single InGaN/GaN nanorod fabricated by a cost-effective top-down approach from a standard LED wafer. The device demonstrates high performance with a reduced quantum confined Stark effect compared with a standard planar counterpart fabricated from the same wafer, confirmed by optical and electrical characterization. Current density as high as 5414 A cm‑2 is achieved without significant damage to the device due to the high internal quantum efficiency. The efficiency droop is mainly ascribed to Auger recombination, which was studied by an ABC model. Our work provides a potential method for fabricating compact light sources for advanced photonic integrated circuits without involving expensive or time-consuming fabrication facilities.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-01-15

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

  13. The Weight of Evidence Does Not Support the Listing of Styrene as “Reasonably Anticipated to be a Human Carcinogen” in NTP's Twelfth Report on Carcinogens

    OpenAIRE

    Rhomberg, Lorenz R.; Goodman, Julie E.; Prueitt, Robyn L.

    2013-01-01

    Styrene was listed as “reasonably anticipated to be a human carcinogen” in the twelfth edition of the National Toxicology Program's Report on Carcinogens based on what we contend are erroneous findings of limited evidence of carcinogenicity in humans, sufficient evidence of carcinogenicity in experimental animals, and supporting mechanistic data. The epidemiology studies show no consistent increased incidence of, or mortality from, any type of cancer. In animal studies, increased incidence ra...

  14. Genotoxicity, carcinogenicity, and mode of action of the fried food mutagen 2-amino-3-methylimidazo[4,5-f]quinoline (IQ).

    OpenAIRE

    Weisburger, J H; Barnes, W S; Lovelette, C A; Tong, C; Tanaka, T; Williams, G.M.

    1986-01-01

    Because mutagens typified by 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) observed in cooked foods are widely consumed, detailed studies of their biochemical and biological properties including carcinogenicity are most important. IQ induces unscheduled DNA synthesis in liver cells, which when taken together with its powerful mutagenicity in the Salmonella typhimurium test system, predicts carcinogenicity. In female Sprague-Dawley rats, IQ did exhibit potent carcinogenicity for the mammary gla...

  15. Identification of 5-lipoxygenase and microsomal prostaglandin E2 synthase-1 as functional targets of the anti-inflammatory and anti-carcinogenic garcinol.

    Science.gov (United States)

    Koeberle, Andreas; Northoff, Hinnak; Werz, Oliver

    2009-05-01

    Garcinol (camboginol) from the fruit rind of Guttiferae species shows anti-carcinogenic and anti-inflammatory properties, but the underlying molecular mechanisms are unclear. Here we show that garcinol potently interferes with 5-lipoxygenase (EC 7.13.11.34) and microsomal prostaglandin (PG)E2 synthase (mPGES)-1 (EC 5.3.99.3), enzymes that play pivotal roles in inflammation and tumorigenesis. In cell-free assays, garcinol inhibited the activity of purified 5-lipoxygenase and blocked the mPGES-1-mediated conversion of PGH2 to PGE2 with IC50 values of 0.1 and 0.3 microM, respectively. Garcinol suppressed 5-lipoxygenase product formation also in intact human neutrophils and reduced PGE2 formation in interleukin-1beta-stimulated A549 human lung carcinoma cells as well as in human whole blood stimulated by lipopolysaccharide. Moreover, garcinol interfered with isolated cyclooxygenase (COX)-1 (EC 1.14.99.1, IC50 = 12 microM) and with the formation of COX-1-derived 12(S)-hydroxy-5-cis-8,10-trans-heptadecatrienoic acid and thromboxane B2 in human platelets. In contrast, neither Ca2+-ionophore (A23187)-induced arachidonic acid release in neutrophils nor COX-2 activity in A549 cells or whole blood, measured as formation of 6-keto PGF1alpha, or isolated human recombinant COX-2 were significantly affected by garcinol (garcinol to selectively suppress PGE2 synthesis and 5-lipoxygenase product formation provides a molecular basis for the anti-inflammatory and anti-carcinogenic effects of garcinol and rationalizes its therapeutic use. PMID:19426689

  16. Carcinogenicity study with technical-grade dichlorodiphenyltrichloroethane and 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene in hamsters.

    Science.gov (United States)

    Rossi, L; Barbieri, O; Sanguineti, M; Cabral, J R; Bruzzi, P; Santi, L

    1983-02-01

    Studies conducted by others have revealed that 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE), a proximal metabolite of dichlorodiphenyltrichloroethane (DDT), is a strong hepatocellular carcinogen in mice. Since hamsters appear to be resistant to tumor induction by DDT, we wanted to investigate whether DDE has any neoplastic effect in this species. DDE (99% pure) was mixed into the diet at doses of 500 or 1000 ppm and given to groups of male and female Syrian golden hamsters for life. Another group of animals received a diet containing 1000 ppm technical-grade DDT, and a further group served as control. Groups contained a minimum of 40 hamsters per sex. The tested compounds had no effect on the incidence of tumors at all sites, compared to controls. A specific finding in animals exposed to DDE was the appearance of hepatocellular tumors late in life. They were classified as neoplastic nodules, and the incidence was 15% in females and 47% in males of the 500-ppm DDE dose groups and 21% in females and 33% in males of the 1000-ppm DDE dose groups. None of the untreated or DDT-treated animals had these tumors. Eight animals treated with 1000 ppm DDE and four of those treated with DDT had hyperplastic foci of the liver. In addition, adrenocortical adenomas, spontaneous to Syrian golden hamsters, were more frequent in DDE- and DDT-treated animals than in control animals. These results showing that DDE, but not its parental compound, induces liver cell tumors in hamsters emphasize the importance of this metabolite as a proximal carcinogen of DDT. PMID:6848191

  17. Multilayer stacked white polymer light-emitting diodes

    International Nuclear Information System (INIS)

    Multilayer stacked white polymer light-emitting diodes (WPLEDs) with a multilayer emitting structure were produced using a stamp transfer printing process. Two light-emitting layers were stacked using a transfer printing method, and the device performance of the WPLEDs was examined. Yellow light-emitting polymers spin coated onto silicone substrates were transferred to a polydimethylsiloxane stamp, which was transferred effectively to the top of blue polymers. White colour coordinates of (0.34, 0.41) were obtained from the multilayer stacked WPLEDs.

  18. Vanadium carcinogenic, immunotoxic and neurotoxic effects: a review of in vitro studies.

    Science.gov (United States)

    Zwolak, Iwona

    2014-01-01

    Deleterious health effects induced by inorganic vanadium compounds are linked with carcinogenic, immunotoxic and neurotoxic insults. The goal of this review is to provide a summary of mammalian cell culture studies (from the 1990s to most recent) looking into the mode of the above-mentioned adverse actions of vanadium. Regarding the carcinogenicity potential, the key cell-based studies have evidenced the ability of vanadium to induce genotoxic lesions, cell morphological transformation and anti-apoptotic effects in a certain type of cells. Two contradictory effects of vanadium on the immune functions of cells have been observed in cell culture studies. The first effect involves reduction of cell immune responses such as vanadium-dependent inhibition of cytokine-inducible functions, which may underlie the mechanism of vanadium-induced immunosuppression. The second one involves stimulation of immune activity, for example, a vanadium-mediated increase in cytokine production, which may contribute to vanadium-related inflammation. So far, an in vitro evaluation of vanadium neurotoxicity has only been reported in few articles. These papers indicate probable cytotoxic mechanisms resulting from exposure of neurons and glial cells to vanadium. In summary, this literature review collects in vitro reports on adverse vanadium effects and thus provides vanadium researchers with a single, concise source of data. PMID:24147425

  19. The carcinogenic risks of low-LET and high-LET ionizing radiations

    International Nuclear Information System (INIS)

    This report presents a discussion on risk from ionizing radiations to human populations. Important new information on human beings has come mainly from further follow-up of existing epidemiological studies, notably the Japanese atomic bomb survivors and the ankylosing spondylitis patients; from new epidemiological surveys, such as the patients treated for cancer of the uterine cervix; and from combined surveys, including workers exposed in underground mines. Since the numerous and complex differences among the different study populations introduce factors that influence the risk estimates derived in ways that are not completely understood, it is not clear how to combine the different risk estimates obtained. These factors involve complex biological and physical variables distributed over time. Because such carcinogenic effects occur too infrequently to be demonstrated at low doses, the risks of low-dose radiation can be estimated only by interpolation from observations at high doses on the basis of theoretical concepts, mathematical models and available empirical evidence, primarily the epidemiological surveys of large populations exposed to ionizing radiation. In spite of a considerable amount of research, only recently has there has been efforts to apply the extensive laboratory data in animals to define the dose-incidence relationship in the low dose region. There simply are insufficient data in the epidemiological studies of large human populations to estimate risk coefficients directly from exposure to low doses. The risk estimates for the carcinogenic effects of radiation have been, in the past, somewhat low and reassessment of the numerical values is now necessary

  20. Impact of environmental exposures on the mutagenicity/carcinogenicity of heterocyclic amines

    International Nuclear Information System (INIS)

    Carcinogenic heterocyclic amines are produced from overcooked foods and are highly mutagenic in most short-term test systems. One of the most abundant of these amines, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), induces breast, colon and prostate tumors in rats. Human dietary epidemiology studies suggest a strong correlation between either meat consumption or well-done muscle meat consumption and cancers of the colon, breast, stomach, lung and esophagus. For over 20 years our laboratory has helped define the human exposure to these dietary carcinogens. In this report we describe how various environmental exposures may modulate the risk from exposure to heterocyclic amines, especially PhIP. To assess the impact of foods on PhIP metabolism in humans, we developed an LC/MS/MS method to analyze the four major PhIP urinary metabolites following the consumption of a single portion of grilled chicken. Adding broccoli to the volunteers' diet altered the kinetics of PhIP metabolism. At the cellular level we have found that PhIP itself stimulates a significant estrogenic response in MCF-7 cells, but even more interestingly, co-incubation of the cells with herbal teas appear to enhance the response. Numerous environmental chemicals found in food or the atmosphere can impact the exposure, metabolism, and cell proliferation response of heterocyclic amines

  1. Preferential binding of growth inhibitory prostaglandins by the target protein of a carcinogen

    Energy Technology Data Exchange (ETDEWEB)

    Khan, S.H.; Sorof, S. (Fox Chase Cancer Center, Philadelphia, PA (United States))

    1990-12-01

    Liver fatty acid binding protein (L-FABP) is the principal target protein of the hepatic carcinogen N-(2-fluorenyl)acetamide (2-acetylaminofluorene) in rat liver. In addition, the cyclopentenone prostaglandins (PG), PGA, PGJ{sub 2}, and {Delta}{sup 12}-PGJ{sub 2}, inhibit the growth of many cell types in vitro. This report describes the preferential binding of the growth inhibitory prostaglandins by L-FABP and the reversible inhibition of thymidine incorporation into DNA by PGA{sub 2} and {Delta}{sup 12}-PGJ{sub 2} in primary cultures of purified rat hepatocytes. As a model ligand, ({sup 3}H)PGA{sub 1} bound to L-FABP specifically, reversibly, rapidly, and with high affinity. Its dissociation constants were 134 nM (high affinity) and 3.6 {mu}M (low affinity). The high-affinity finding of ({sup 3}H)PGA{sup 1} correlated with their growth inhibitory activities reported previously and here. The in vitro actions of L-FABP are compatible with those of a specific and dissociable carrier of growth inhibitory prostaglandins in rat hepatocytes and suggest that the carcinogen may usurp the cellular machinery of the growth inhibitory prostaglandins.

  2. Protein adducts of the prostate carcinogen PhIP in children

    Energy Technology Data Exchange (ETDEWEB)

    Lawrence Livermore National Laboratory

    2004-02-20

    Prostate cancer is the second leading cause of cancer death in men in the United States. few epidemiology studies have indicated that exposure to PhIP, a rodent prostate carcinogen formed in meat during cooking, may be an important risk factor for prostate cancer in humans. Therefore, a highly sensitive biomarker assay is urgently needed to clarify the role of PhIP in prostate cancer. The goal of this project is to develop an assay that can be used to more accurately quantify human exposure to PhIP and potential prostate cancer risk. Our hypothesis is that an Accelerator Mass Spectrometry-based method can be developed to measure protein adducts of PhIP in the blood of humans. This will provide a measure of the internal dose, as well as the capacity for carcinogen bioactivation to a form that can initiate the cancer process. Towards this goal, we have characterized an adduct formed by PhIP in vitro with the amino acid cysteine. This adduct should provide a biomarker of dietary PhIP exposure and potential prostate cancer risk that could be used to identify individuals for prevention and for monitoring the effect chemoprevention strategies.

  3. Formation of carcinogenic 4(5)-methylimidazole in caramel model systems: a role of sulphite.

    Science.gov (United States)

    Lee, Kwang-Geun; Jang, Haewon; Shibamoto, Takayuki

    2013-02-15

    Aqueous caramel model systems consisted the D-glucose/NH(3)/sulphite were heated at 100°C for 2 h and amounts of carcinogenic 4(5)-methylimidazole (4-MI) formed were determined. The amount formed ranged from 7.0 to 155.0 ppm. A system with 0.1 M sulphite yielded the greatest amount of 4-MI, which was 54% more than that yielded from a system without sulphite. When the amount of sulphite increased over 0.1 M, the amount of 4-MI reduced. The greatest reduction was achieved with 0.2 M sulphite by 68% compared to 0 M sulphite, suggesting that sulphite plays an important role in the formation of carcinogenic 4-MI in caramel colour. Also, a system with 0.1 M sulphite yielded the most intense caramel colour but the other levels of sulphite did not change the colour intensity significantly. Sulphite contributed slightly to the level of flavour chemicals evaluated using pyrazine formation. The results suggest that sulphite addition at appropriate amount reduces 4-MI formation in caramel colour without sacrificing flavour and colour formation. PMID:23194510

  4. Impact of Environmental Exposures on the Mutagenicity/Carcinogenicity of Heterocyclic Amines

    Energy Technology Data Exchange (ETDEWEB)

    Felton, J S; Knize, M G; Bennett, L M; Malfatti, M A; Colvin, M E; Kulp, K S

    2003-12-19

    Carcinogenic heterocyclic amines are produced from overcooked foods and are highly mutagenic in most short-term test systems. One of the most abundant of these amines, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), induces breast, colon and prostate tumors in rats. Human dietary epidemiology studies suggest a strong correlation between either meat consumption or well-done muscle meat consumption and cancers of the colon, breast, stomach, lung and esophagus. For over 20 years our laboratory has helped define the human exposure to these dietary carcinogens. In this report we describe how various environmental exposures may modulate the risk from exposure to heterocyclic amines, especially PhIP. To assess the impact of foods on PhIP metabolism in humans, we developed an LC/MS/MS method to analyze the four major PhIP urinary metabolites following the consumption of a single portion of grilled chicken. Adding broccoli to the volunteers' diet altered the kinetics of PhIP metabolism. At the cellular level we have found that PhIP itself stimulates a significant estrogenic response in MCF-7 cells, but even more interestingly, co-incubation of the cells with herbal teas appear to enhance the response. Numerous environmental chemicals found in food or the atmosphere can impact the exposure, metabolism, and cell proliferation response of heterocyclic amines.

  5. The OSIRIS Weight of Evidence approach: ITS mutagenicity and ITS carcinogenicity.

    Science.gov (United States)

    Buist, Harrie; Aldenberg, Tom; Batke, Monika; Escher, Sylvia; Klein Entink, Rinke; Kühne, Ralph; Marquart, Hans; Pauné, Eduard; Rorije, Emiel; Schüürmann, Gerrit; Kroese, Dinant

    2013-11-01

    Risk assessment of chemicals usually implies data evaluation of in vivo tests in rodents to conclude on their hazards. The FP7 European project OSIRIS has developed integrated testing strategies (ITS) for relevant toxicological endpoints to avoid unnecessary animal testing and thus to reduce time and costs. This paper describes the implementation of ITS mutagenicity and carcinogenicity in the public OSIRIS webtool. The data requirements of REACH formed the basis for these ITS. The main goal was to implement procedures to reach a conclusion on the adequacy and validity of available data. For the mutagenicity ITS a quantitative Weight of Evidence approach based on Bayesian statistics was developed and implemented. The approach allows an overall quality assessment of all available data for the five types of mutagenicity data requirements: in vitro bacterial mutagenicity, in vitro and in vivo chromosome aberration, in vitro and in vivo mammalian mutagenicity. For the carcinogenicity ITS a tool was developed to evaluate the quality of studies not conforming (entirely) to guidelines. In a tiered approach three quality aspects are assessed: documentation (reliability), study design (adequacy) and scope of examination (validity). The quality assessment is based on expert and data driven quantitative Weight of Evidence. PMID:23357514

  6. Animal carcinogenicity studies on radiofrequency fields related to mobile phones and base stations

    International Nuclear Information System (INIS)

    Since a report in 1997 on an increased lymphoma incidence in mice chronically exposed to a mobile phone radiofrequency signal, none of the subsequent long-term studies in rodents have confirmed these results. On the other hand, several of the follow-up co- and carcinogenicity studies are still underway or are presently being initiated. Most of the published long-term studies used 1 exposure level only and suffer from a poor dosimetry which does not consider the animal's growth. Additional points of criticism are a limited, in some cases, questionable histopathology and inadequate group sizes. Overall, if dealing with new chemicals or drugs, these studies would not be acceptable for registration with the responsible authorities. The major critical points are taken into consideration within the European co- and carcinogenicity projects (CEMFEC and PERFORM-A), which are in their final stages and in the US long-term studies in mice and rats which are about to be initiated. Nevertheless, the WHO evaluation for health risk assessment of long-term telephone use and base station exposure will start in late 2005

  7. Preferential binding of growth inhibitory prostaglandins by the target protein of a carcinogen

    International Nuclear Information System (INIS)

    Liver fatty acid binding protein (L-FABP) is the principal target protein of the hepatic carcinogen N-(2-fluorenyl)acetamide (2-acetylaminofluorene) in rat liver. In addition, the cyclopentenone prostaglandins (PG), PGA, PGJ2, and Δ12-PGJ2, inhibit the growth of many cell types in vitro. This report describes the preferential binding of the growth inhibitory prostaglandins by L-FABP and the reversible inhibition of thymidine incorporation into DNA by PGA2 and Δ12-PGJ2 in primary cultures of purified rat hepatocytes. As a model ligand, [3H]PGA1 bound to L-FABP specifically, reversibly, rapidly, and with high affinity. Its dissociation constants were 134 nM (high affinity) and 3.6 μM (low affinity). The high-affinity finding of [3H]PGA1 correlated with their growth inhibitory activities reported previously and here. The in vitro actions of L-FABP are compatible with those of a specific and dissociable carrier of growth inhibitory prostaglandins in rat hepatocytes and suggest that the carcinogen may usurp the cellular machinery of the growth inhibitory prostaglandins

  8. Biodegradation of the metallic carcinogen hexavalent chromium Cr(VI by an indigenously isolated bacterial strain

    Directory of Open Access Journals (Sweden)

    Das Alok

    2010-01-01

    Full Text Available Background : Hexavalent chromium [Cr(VI], a potential mutagen and carcinogen, is regularly introduced into the environment through diverse anthropogenic activities, including electroplating, leather tanning, and pigment manufacturing. Human exposure to this toxic metal ion not only causes potential human health hazards but also affects other life forms. The World Health Organization, the International Agency for Research on Cancer, and the Environmental Protection Agency have determined that Cr(VI compounds are known human carcinogens. The Sukinda valley in Jajpur District, Orissa, is known for its deposit of chromite ore, producing nearly 98% of the chromite ore in India and one of the prime open cast chromite ore mines in the world (CES, Orissa Newsletter. Materials and Methods: Our investigation involved microbial remediation of Cr(VI without producing any byproduct. Bacterial cultures tolerating high concentrations of Cr were isolated from the soil sample collected from the chromite-contaminated sites of Sukinda, and their bioaccumulation properties were investigated. Strains capable of growing at 250 mg/L Cr(VI were considered as Cr resistant. Results: The experimental investigation showed the maximum specific Cr uptake at pH 7 and temperature 30oC. At about 50 mg/L initial Cr(VI concentrations, uptake of the selected potential strain exceeded 98% within 12 h of incubation. The bacterial isolate was identified by 16S rRNA sequencing as Brevebacterium casei. Conclusion: Results indicated promising approach for microbial remediation of effluents containing elevated levels of Cr(VI.

  9. Non-carcinogenic health risks of heavy metal in mudfish from Laguna Lake

    Directory of Open Access Journals (Sweden)

    Victorio B. Molina

    2012-06-01

    Full Text Available This paper examines the potential risks to human health associated with exposure to heavy metal that have bioaccumulated in Mudfish (Ophicephalus striatus from Laguna Lake. Fish samples were collected in eight sampling stations in three major areas of the lake during the dry and wet seasons. Dry season samples were collected from May to June 2010 and wet season samples, from September to November 2010. Coordinates of sampling site locations were recorded using Global Positioning System (GPS and plotted in Geographic Information System (GIS digital maps. Heavy metal analyses for cadmium (Cd, lead (Pb, mercury (Hg, arsenic (As, and chromium (Cr were conducted using Atomic Absorption Spectrophotometer (AAS and a Mercury Analyzer (Mercur-Duo. Estimates of health risks associated with mudfish consumption were summarized according to non-carcinogenic effects. Non-carcinogenic Hazard Quotient (NHQ values of five heavy metal showed that lead is the most urgent pollutant of concern in terms of adverse health effects from risks associated with mudfish consumption from all sampling locations in the lake. From the point of view of human health protection and disease prevention, mudfish from Laguna Lake is not fit for long-term human consumption primarily due to lead and mercury contamination.

  10. Evaluation of genome damage in subjects occupationally exposed to possible carcinogens.

    Science.gov (United States)

    Zeljezic, Davor; Mladinic, Marin; Kopjar, Nevenka; Radulovic, Azra Hursidic

    2016-09-01

    In occupational exposures, populations are simultaneously exposed to a mixture of chemicals. We aimed to evaluate DNA damage due to possible carcinogen exposure (phenylhydrazine, ethylene oxide, dichloromethane, and 1,2-dichloroethane) in lymphocytes of pharmaceutical industry workers from the same production line. Population comprised 16 subjects (9 females and 7 males) who were exposed to multiple chemicals for 8 months. Genome damage was assessed using alkaline comet assay, micronucleus assay, and comet assay coupled with fluorescent in situ hybridization (comet-FISH). After 8 months of exposure, the issue of irregular use of all available personal protective equipment (PPE) came into light. To decrease the risk of exposure, strict use of PPE was enforced. After 8 months of strict PPE use, micronuclei frequency and comet assay parameters in lymphocytes of pharmaceutical workers significantly decreased compared with prior period of irregular PPE use. Comet-FISH results indicated a significant shift in distribution of signals for the TP 53 gene toward a more frequent occurrence in the comet tail. Prolonged exposure to possible carcinogens may hinder DNA repair mechanisms and affect structural integrity of TP 53 Two indicators of loss of TP 53 gene integrity have risen, namely, TP 53 fragmentation rate in lymphocytes with persistently elevated primary damage and incidence of TP 53 deletions in undamaged lymphocytes. PMID:25653038

  11. Human gastric cancer, Helicobacter pylori and bracken carcinogens: A connecting hypothesis.

    Science.gov (United States)

    Oliveros-Bastidas, Alberto; Calcagno-Pissarelli, María Pía; Naya, Marlene; Ávila-Núñez, Jorge Luis; Alonso-Amelot, Miguel E

    2016-03-01

    Long term infection of Helicobacter pylori (Hp) virulent strains is a key factor in the genesis of human gastric cancer, and so are certain dietary proinflammatory and genotoxic compounds. Carcinogenic bracken fern (Pteridium spp.) is one of these. Toxins from this plant are consumed as bracken culinary preparations, through milk and meat of bracken-exposed livestock, and drain waters from bracken swards. Bracken toxin ptaquiloside (PtQ), a suspected human carcinogen, elicits complex responses in animals leading to death. PtQ and Hp might cooperate in gastric pathologies. This paper presents an hypothesis on PtQ-Hp association leading to the enhancement of carcinogenesis in the human gastric environment that might explain the high gastric cancer incidence and death rates among Hp-infected people living in bracken zones at two levels: (1) The macroscopic scale comprising the flow of PtQ in the human diet. (2) the microscopic scale encompassing (A) gastric luminal medium; (B) gastric mucus structure and mucin degradation elicited by Hp; (C) bacterial pH gradient modification of the gastric mucosa that favors PtQ survival and its penetration into epithelial tissue; (D) combined PtQ/Hp effects on gastric immune and inflammatory responses; (E) PtQ-Hp complementary activity at selected cell signaling cascades and genome disturbance. PMID:26632203

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

    International Nuclear Information System (INIS)

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

  13. Exposure and Metabolic Activation Biomarkers of Carcinogenic Tobacco-Specific Nitrosamines.

    Science.gov (United States)

    Hecht, Stephen S; Stepanov, Irina; Carmella, Steven G

    2016-01-19

    Lung cancer is the leading cause of cancer death in the world, and cigarette smoking is its main cause. Oral cavity cancer is another debilitating and often fatal cancer closely linked to tobacco product use. While great strides have been made in decreasing tobacco use in the United States and some other countries, there are still an estimated 1 billion men and 250 million women in the world who are cigarette smokers and there are hundreds of millions of smokeless tobacco users, all at risk for cancer. Worldwide, lung cancer kills about three people per minute. This Account focuses on metabolites and biomarkers of two powerful tobacco-specific nitrosamine carcinogens, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and N'-nitrosonornicotine (NNN), considered to be among the main causes of lung cancer and oral cavity cancer in people who use tobacco products. Three properties of NNK and NNN are critical for successful biomarker studies: they are present in all tobacco products, they are tobacco-specific and are not found in any other product, and they are strong carcinogens. NNK and NNN are converted in humans to urinary metabolites that can be quantified by mass spectrometry as biomarkers of exposure to these carcinogens. They are also metabolized to diazonium ions and related electrophiles that react with DNA to form addition products that can be detected and quantified by mass spectrometry. These urinary metabolites and DNA addition products can serve as biomarkers of exposure and metabolic activation, respectively. The biomarkers of exposure, in particular the urinary NNK metabolites 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) and its glucuronides, have been extensively applied to document tobacco-specific lung carcinogen uptake in smokers and nonsmokers exposed to secondhand tobacco smoke. Highly sensitive mass spectrometric methods have been developed for quantitative analysis of these NNK metabolites as well as metabolites of NNN in human urine

  14. Experience from a long-term carcinogenicity study with intraperitoneal injection of biosoluble synthetic mineral fibers.

    Science.gov (United States)

    Grimm, Hans G; Bernstein, David M; Attia, Mahmoud; Richard, Jacques; De Reydellet, Aymon

    2002-08-01

    The carcinogenic potential in the intraperitoneal cavity of three newly developed biosoluble insulation glass wool fibers (M, P, and V) and one newly developed biosoluble insulation stone wool fiber (O) was investigated and compared to that of a previously developed soluble glass fiber (B). The in vitro dissolution coefficient of the three glass wool fibers ranged from 450 to 1037 ng/cm(2) x h and was 523 ng/cm(2) x h for the stone wool fiber. The in vitro dissolution coefficient of the B fiber was 580 ng/cm(2) x h. Groups of female Wistar rats (strain Crl: Wi BR) were exposed by repeated injections to doses of 0.5, 2, and 5 x 10(9) WHO fibers, which corresponds to between 41 mg to 724 mg fiber injected. In addition, 2 groups of crocidolite were used as positive controls at doses of 0.1 x 10(9) and 1 x 10(9) WHO fibers (0.5 and 5 mg). The in vitro dissolution coefficient of crocidolite is estimated to be approximately 1 ng/cm(2) x h. The protocol of the study and the size distribution of the test samples conformed to the European Commission Protocol EUR 18748 EN, and the study was executed under Good Laboratory Practice conditions. Two of the new insulation wools, fibers M and 0, showed no statistically significant tumorigenic response even at the very high dose of 5 x 10(9) WHO fibers injected. Fibers P and V showed a small tumorigenic response in the ip cavity similar in magnitude to the B fiber, which has been declared in the German fiber regulations as a noncarcinogenic fiber. The response to the soluble insulation fibers was notably different from that of the known carcinogen crocidolite, which produced 53% tumors at a comparatively low dose of 0.1 x 10(9) WHO fibers. The incidence of mesothelioma was found to be highly correlated to the incidence of intra-abdominal nodules and masses at different sites. The incidence of abdominal nodules and masses was highly correlated to the number of animals with ascites. The incidence of chronic peritonitis with fibrotic

  15. Efficient Top-Emitting Polymer Light-Emitting Diodes Using Chromium as Anode

    Institute of Scientific and Technical Information of China (English)

    HUANG Yong; XU Yun-Hua; XU Wei; ZHOU Jian-Gang; PENG Jun-Biao; CAO Yong

    2007-01-01

    We demonstrate a high efficiency top-emitting polymer light-emitting diode (TPLED) with chromium (Cr) taking as the anode. The TPLED structure is Cr/poly-3, 4-ethylenedioxythiophene (PEDOT:PSS)/poly [2-(4-3',7'-dimethyloctyloxy)-phenyl]-p-phenylenevinylene) (P-PPV)/Ba/Ag. The Cr (100nm) anode is prepared by sputterdepositing in a vacuum chamber. It is found that the device emissive properties are affected dramatically by the thickness of both PEDOT:PSS and the Ag cathode. Optimized thicknesses of PEDOT:PSS and Ag layer are 60nm and 15 nm, respectively. The diode exhibits excellent electroluminescence (EL) properties, such as a turn-on voltage of 3.32 V, luminous efficiency of 4.41 cd/A and luminance of 6989cd/m2 at driving voltage of about 9 V.

  16. PURIFIED POLAR POLYFLUORENE FOR LIGHT-EMITTING DIODES AND LIGHT-EMITTING ELECTROCHEMICAL CELLS

    Institute of Scientific and Technical Information of China (English)

    Ming-liang Sun; Cheng-mei Zhong; Feng Li; Qi-bing Pei

    2012-01-01

    Conjugated ployfluorene with 2-(2-(2-methoxyethoxy)ethoxy)ethyl groups (EO-PF) is prepared by the palladiumcatalyzed Suzuki coupling reaction.The polymer is purified carefully by a simple chemical procedure.The inductively coupled plasma (ICP) test shows palladium-catalyst in the polymer can be removed by this procedure.The thermal properties,electrochemical properties,UV-Vis absorption properties,photoluminescence properties and electroluminescent properties of the polymer without (EO-PF1) or with purification (EO-PF2) are studied.EO-PF2 shows better PL CIE coordinates in THF solutions as blue light-emitting materials and better photoluminescence stability in thin solid films.Polymer light emitting diodes and electrochemical cells based on EO-PF2 exhibit somewhat improved optoelectronic performance than control devices of EO-PF1.

  17. 2,3,7,8-Tetrachlorodibenzo-p-dioxin has both pro-carcinogenic and anti-carcinogenic effects on neuroendocrine prostate carcinoma formation in TRAMP mice.

    Science.gov (United States)

    Moore, Robert W; Fritz, Wayne A; Schneider, Andrew J; Lin, Tien-Min; Branam, Amanda M; Safe, Stephen; Peterson, Richard E

    2016-08-15

    It is well established that the prototypical aryl hydrocarbon receptor (AHR) agonist 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) can both cause and protect against carcinogenesis in non-transgenic rodents. But because these animals almost never develop prostate cancer with old age or after carcinogen exposure, whether AHR activation can affect cancer of the prostate remained unknown. We used animals designed to develop this disease, Transgenic Adenocarcinoma of the Mouse Prostate (TRAMP) mice, to investigate the potential role of AHR signaling in prostate cancer development. We previously reported that AHR itself has prostate tumor suppressive functions in TRAMP mice; i.e., TRAMP mice in which Ahr was knocked out developed neuroendocrine prostate carcinomas (NEPC) with much greater frequency than did those with both Ahr alleles. In the present study we investigated effects of AHR activation by three different xenobiotics. In utero and lactational TCDD exposure significantly increased NEPC tumor incidence in TRAMP males, while chronic TCDD treatment in adulthood had the opposite effect, a significant reduction in NEPC incidence. Chronic treatment of adult TRAMP mice with the low-toxicity selective AHR modulators indole-3-carbinol or 3,3'-diindolylmethane did not significantly protect against these tumors. Thus, we demonstrate, for the first time, that ligand-dependent activation of the AHR can alter prostate cancer incidence. The nature of the responses depended on the timing of AHR activation and ligand structures. PMID:27151233

  18. Faunal effects on the distribution of gamma emitting radionuclides in four forested soils

    International Nuclear Information System (INIS)

    Four forested, well drained surface horizons of soils representing the range of textures located in the Lake Erie Basin of Southern Ontario were sampled in 1 cm increments to a depth of 15 cm. Gamma emitting radionuclides of natural sources, 40K, 214Bi (238U daughter), and 208Tl (232Th daughter), are distributed as a function of texture over the 15 cm depth. Increasing clay content results in increased retention of these isotopes. The 40K distribution is a result of the amount of organic carbon present. Increased organic carbon results in increased weathering and lower 40K values. Differing earthworm activity results in distinct distributions of 137Cs, a gamma emitting radionuclide from bomb fallout, within the four soils. Larger numbers and biomass of anecic earthworms in finer textured soils result in a linear distribution of 137Cs with depth. Endogeous species in the coarsest textured soil result in little incorporation of 137Cs with depth

  19. Chronic occupational exposure to arsenic induces carcinogenic gene signaling networks and neoplastic transformation in human lung epithelial cells

    International Nuclear Information System (INIS)

    Chronic arsenic exposure remains a human health risk; however a clear mode of action to understand gene signaling-driven arsenic carcinogenesis is currently lacking. This study chronically exposed human lung epithelial BEAS-2B cells to low-dose arsenic trioxide to elucidate cancer promoting gene signaling networks associated with arsenic-transformed (B-As) cells. Following a 6 month exposure, exposed cells were assessed for enhanced cell proliferation, colony formation, invasion ability and in vivo tumor formation compared to control cell lines. Collected mRNA was subjected to whole genome expression microarray profiling followed by in silico Ingenuity Pathway Analysis (IPA) to identify lung carcinogenesis modes of action. B-As cells displayed significant increases in proliferation, colony formation and invasion ability compared to BEAS-2B cells. B-As injections into nude mice resulted in development of primary and secondary metastatic tumors. Arsenic exposure resulted in widespread up-regulation of genes associated with mitochondrial metabolism and increased reactive oxygen species protection suggesting mitochondrial dysfunction. Carcinogenic initiation via reactive oxygen species and epigenetic mechanisms was further supported by altered DNA repair, histone, and ROS-sensitive signaling. NF-κB, MAPK and NCOR1 signaling disrupted PPARα/δ-mediated lipid homeostasis. A ‘pro-cancer’ gene signaling network identified increased survival, proliferation, inflammation, metabolism, anti-apoptosis and mobility signaling. IPA-ranked signaling networks identified altered p21, EF1α, Akt, MAPK, and NF-κB signaling networks promoting genetic disorder, altered cell cycle, cancer and changes in nucleic acid and energy metabolism. In conclusion, transformed B-As cells with their whole genome expression profile provide an in vitro arsenic model for future lung cancer signaling research and data for chronic arsenic exposure risk assessment. Highlights: ► Chronic As2O3

  20. Chronic occupational exposure to arsenic induces carcinogenic gene signaling networks and neoplastic transformation in human lung epithelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Stueckle, Todd A., E-mail: tstueckle@hsc.wvu.edu [Department of Basic Pharmaceutical Sciences, West Virginia University, Morgantown, WV 26506 (United States); Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV 26505 (United States); Lu, Yongju, E-mail: yongju6@hotmail.com [Department of Basic Pharmaceutical Sciences, West Virginia University, Morgantown, WV 26506 (United States); Davis, Mary E., E-mail: mdavis@wvu.edu [Department of Physiology, West Virginia University, Morgantown, WV 26506 (United States); Wang, Liying, E-mail: lmw6@cdc.gov [Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV 26505 (United States); Jiang, Bing-Hua, E-mail: bhjiang@jefferson.edu [Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107 (United States); Holaskova, Ida, E-mail: iholaskova@hsc.wvu.edu [Department of Microbiology, Immunology and Cell Biology, West Virginia University, Morgantown, WV 26506 (United States); Schafer, Rosana, E-mail: rschafer@hsc.wvu.edu [Department of Microbiology, Immunology and Cell Biology, West Virginia University, Morgantown, WV 26506 (United States); Barnett, John B., E-mail: jbarnett@hsc.wvu.edu [Department of Microbiology, Immunology and Cell Biology, West Virginia University, Morgantown, WV 26506 (United States); Rojanasakul, Yon, E-mail: yrojan@hsc.wvu.edu [Department of Basic Pharmaceutical Sciences, West Virginia University, Morgantown, WV 26506 (United States)

    2012-06-01

    Chronic arsenic exposure remains a human health risk; however a clear mode of action to understand gene signaling-driven arsenic carcinogenesis is currently lacking. This study chronically exposed human lung epithelial BEAS-2B cells to low-dose arsenic trioxide to elucidate cancer promoting gene signaling networks associated with arsenic-transformed (B-As) cells. Following a 6 month exposure, exposed cells were assessed for enhanced cell proliferation, colony formation, invasion ability and in vivo tumor formation compared to control cell lines. Collected mRNA was subjected to whole genome expression microarray profiling followed by in silico Ingenuity Pathway Analysis (IPA) to identify lung carcinogenesis modes of action. B-As cells displayed significant increases in proliferation, colony formation and invasion ability compared to BEAS-2B cells. B-As injections into nude mice resulted in development of primary and secondary metastatic tumors. Arsenic exposure resulted in widespread up-regulation of genes associated with mitochondrial metabolism and increased reactive oxygen species protection suggesting mitochondrial dysfunction. Carcinogenic initiation via reactive oxygen species and epigenetic mechanisms was further supported by altered DNA repair, histone, and ROS-sensitive signaling. NF-κB, MAPK and NCOR1 signaling disrupted PPARα/δ-mediated lipid homeostasis. A ‘pro-cancer’ gene signaling network identified increased survival, proliferation, inflammation, metabolism, anti-apoptosis and mobility signaling. IPA-ranked signaling networks identified altered p21, EF1α, Akt, MAPK, and NF-κB signaling networks promoting genetic disorder, altered cell cycle, cancer and changes in nucleic acid and energy metabolism. In conclusion, transformed B-As cells with their whole genome expression profile provide an in vitro arsenic model for future lung cancer signaling research and data for chronic arsenic exposure risk assessment. Highlights: ► Chronic As{sub 2}O

  1. Effects of combined exposure of F344 rats to inhaled 239PuO2 and a chemical carcinogen (NNK)

    International Nuclear Information System (INIS)

    Workers in nuclear weapons facilitates have a significant potential for exposure to chemical carcinogens and to radiation from external sources or from internally deposited radionuclides such as 239Pu. Although the carcinogenic effects of inhaled 239Pu and many chemicals have been studied individually, very little information is available on their combined effects. One chemical carcinogen that workers could be exposed to, via tobacco smoke, is the tobacco-specific nitrosamine 4-(N-Methyl-N-nitrosamino)-1-(3-pyridyl)-1-butanone (NNK), a product of the curing of tobacco and pyrolysis of nicotine in tobacco. NNK causes lung tumors in rats, regardless of the route of administration and to a lesser extent tumors in the liver, nasal passages, and pancreas. The purpose of this study is to characterize the effects of combined exposure of rats to NNK and internally deposited plutonium, as well as to these agents alone

  2. Electron injection into hole-transporting layer from emitting layer in organic light emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Tsuboi, Taiju [Faculty of Engineering, Kyoto Sangyo University, Kamigamo (Japan); Kishimoto, Tadahi; Wako, Kazuhiro [Research Institute for Advanced Liquid Crystal Technology, Aomori (Japan); Matsuda, Kuniharu; Iguchi, Hirofumi [Tohoku Device Co., Ltd., Hanamaki, Iwate (Japan)

    2011-09-15

    Optical and electrical characteristics of organic light emitting diode devices with emitting layer of N,N'-di(naphthalene-1-yl)-N,N'-diphenyl-benzidine (NPB) doped with 0.2, 0.5, and 1.0% tris[1-phenylisoquinolinato-C2, N] iridium [Ir(piq){sub 3}] are presented. Tris(8-hydroxyquinoline) aluminum (Alq{sub 3}) and NPB were used as electron and hole transport layers, respectively. Emissions from Ir(piq){sub 3} dopant and Alq{sub 3} have been observed in all the devices. No emission from NPB host was observed even in device with 0.2% dopant concentration. This is understood by the high HOMO gap (0.8 eV) between NPB and Alq{sub 3} and by the very small HOMO gap (0.1 eV) between Ir(piq){sub 3} and Alq{sub 3}, which do not lead to injection of electrons from Alq{sub 3} electron transport layer into NPB host in emitting layer but lead to direct injection of electrons from Alq{sub 3} into Ir(piq){sub 3}. It was found that the driving voltage, external quantum efficiency, and luminous efficiency increase with increasing dopant concentration, but power efficiency decrease. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  3. Recent Advances in Conjugated Polymers for Light Emitting Devices

    Directory of Open Access Journals (Sweden)

    Mohan Raja

    2011-03-01

    Full Text Available A recent advance in the field of light emitting polymers has been the discovery of electroluminescent conjugated polymers, that is, kind of fluorescent polymers that emit light when excited by the flow of an electric current. These new generation fluorescent materials may now challenge the domination by inorganic semiconductor materials of the commercial market in light-emitting devices such as light-emitting diodes (LED and polymer laser devices. This review provides information on unique properties of conjugated polymers and how they have been optimized to generate these properties. The review is organized in three sections focusing on the major advances in light emitting materials, recent literature survey and understanding the desirable properties as well as modern solid state lighting and displays. Recently, developed conjugated polymers are also functioning as roll-up displays for computers and mobile phones, flexible solar panels for power portable equipment as well as organic light emitting diodes in displays, in which television screens, luminous traffic, information signs, and light-emitting wallpaper in homes are also expected to broaden the use of conjugated polymers as light emitting polymers. The purpose of this review paper is to examine conjugated polymers in light emitting diodes (LEDs in addition to organic solid state laser. Furthermore, since conjugated polymers have been approved as light-emitting organic materials similar to inorganic semiconductors, it is clear to motivate these organic light-emitting devices (OLEDs and organic lasers for modern lighting in terms of energy saving ability. In addition, future aspects of conjugated polymers in LEDs were also highlighted in this review.

  4. Recent advances in conjugated polymers for light emitting devices.

    Science.gov (United States)

    Alsalhi, Mohamad Saleh; Alam, Javed; Dass, Lawrence Arockiasamy; Raja, Mohan

    2011-01-01

    A recent advance in the field of light emitting polymers has been the discovery of electroluminescent conjugated polymers, that is, kind of fluorescent polymers that emit light when excited by the flow of an electric current. These new generation fluorescent materials may now challenge the domination by inorganic semiconductor materials of the commercial market in light-emitting devices such as light-emitting diodes (LED) and polymer laser devices. This review provides information on unique properties of conjugated polymers and how they have been optimized to generate these properties. The review is organized in three sections focusing on the major advances in light emitting materials, recent literature survey and understanding the desirable properties as well as modern solid state lighting and displays. Recently, developed conjugated polymers are also functioning as roll-up displays for computers and mobile phones, flexible solar panels for power portable equipment as well as organic light emitting diodes in displays, in which television screens, luminous traffic, information signs, and light-emitting wallpaper in homes are also expected to broaden the use of conjugated polymers as light emitting polymers. The purpose of this review paper is to examine conjugated polymers in light emitting diodes (LEDs) in addition to organic solid state laser. Furthermore, since conjugated polymers have been approved as light-emitting organic materials similar to inorganic semiconductors, it is clear to motivate these organic light-emitting devices (OLEDs) and organic lasers for modern lighting in terms of energy saving ability. In addition, future aspects of conjugated polymers in LEDs were also highlighted in this review. PMID:21673938

  5. Low Doses of the Carcinogen Furan Alter Cell Cycle and Apoptosis Gene Expression in Rat Liver Independent of DNA Methylation

    OpenAIRE

    Tao CHEN; Mally, Angela; Ozden, Sibel; Chipman, J. Kevin

    2010-01-01

    Background Evidence of potent rodent carcinogenicity via an unclear mechanism suggests that furan in various foods [leading to an intake of up to 3.5 μg/kg body weight (bw)/day] may present a potential risk to human health. Objectives We tested the hypothesis that altered expression of genes related to cell cycle control, apoptosis, and DNA damage may contribute to the carcinogenicity of furan in rodents. In addition, we investigated the reversibility of such changes and the potential role of...

  6. Repair of DNA treated with γ-irradiation and chemical carcinogens. Final report, June 1, 1981-May 31, 1984

    International Nuclear Information System (INIS)

    Work done in the past three years has been on DNA repair, on genetic transposition and on the effect of carcinogens on alu sequence transcription. DNA repair work was completed on β-propiolactone DNA adducts, on procaryotic and eucaryotic enzymes capable of removal of 3-methyladenine from DNA, and on in vitro repair of neucleosomal core particle DNA and chromatin DNA. Attempts were made to isolate a human transposable element through the isolation of double stranded RNA and probing of a human library. Experiments were also done to determine whether carcinogens altered the expression of alu sequences in human DNA

  7. Evaluation of the E mu-pim-1 transgenic mouse model for short-term carcinogenicity testing

    DEFF Research Database (Denmark)

    van Kreijl, C. F.; van Oordt, C. W. V.; Kroese, E. D.; Sørensen, Ilona Kryspin; Breuer, M. L.; Storer, R. D.

    1998-01-01

    present article, the results from 2 recent short-term assays (with mitomycin C and x-rays) are briefly presented, together with a review of all 11 performed bioassays and their corresponding histopathologic and molecular data. The overall results allow the first evaluation of the E mu-pim-1 mouse model...... with regard to its usefulness in short-term carcinogenicity testing. It has been shown that the model is primarily suitable as a sensitive short-term assay for genotoxic carcinogens that not only induce (at least) gene mutations and/or large deletions and rearrangements but that also sufficiently...

  8. Low energy, photon emitting nuclides: reference spectra library

    International Nuclear Information System (INIS)

    This section presents a reference library consisting of the measured spectral response of the NaI(Tl)-CsI(Tl) detector to individual low energy photon-emitting nuclides in a point source geometry. The reference spectra collection will be limited to radionuclides which emit photons in the energy range below 20 keV

  9. Radiobiology in clinical radiation therapy - Part IV: Long term risks - Carcinogenic, hereditary, and teratogenetic effects

    International Nuclear Information System (INIS)

    The long-term risks induced by radiation are of much concern to patients and clinicians alike. As an example, perceived radiation risks are frequently cited in a woman's decision to choose a radical mastectomy over lumpectomy + radiation. In consequence, the actual radiation risks are often considerably overstated, or unreasonably downplayed. In this lecture we will discuss just what is known about the long term risks following radiotherapy, both from the human experience and from the laboratory. We will discuss risks both to the patient and to radiotherapy personnel. A good deal is known about the carcinogenic effects of high and low doses of radiation, in large part thanks to the careful study of the survivors of the atomic bombing in Japan, as well as studies of individuals exposed to medical x rays. It is possible to make an estimate, which is probably good to within a factor of, perhaps, three to five, of the cancer risks faced by a patient of a particular age and sex who is going to undergo a particular radiotherapeutic regimen. It is also possible to make an estimate of the risks faced by radiotherapy and nursing staff exposed to low doses. Brachytherapy related risk estimates are likely to be somewhat more uncertain, due to the poorly known sparing effects of the low dose rates used; for the radiotherapy personnel in brachytherapy, because of the doses which can be received, the risks can be quite significant. A recent complication in external-beam radiotherapy is the advent of high-energy linacs, which can produce a significant fast neutron dose which, dose for dose, may be ten to fifty times more carcinogenic than gamma rays. Data relating to the risks of hereditary effects of radiation come almost entirely from laboratory experiments in animals. Studies involving several million mice form the basis of most of our current understanding of hereditary effects. The results of these studies indicate that radiation is a relatively inefficient mutagen. The

  10. Radiobiology in clinical radiation therapy: Long term risks - Carcinogenic, hereditary, and teratogenetic effects

    International Nuclear Information System (INIS)

    The long-term risks induced by radiation are of much concern to patients and clinicians alike. As an example, perceived radiation risks are frequently cited in a woman's decision to choose a radical mastectomy over lumpectomy + radiation. In consequence, the actual radiation risks are often considerably overstated, or unreasonably downplayed. In this lecture we will discuss just what is known about the long term risks following radiotherapy, both from the human experience and from the laboratory. We will discuss risks both to the patient and to radiotherapy personnel. A good deal is known about the carcinogenic effects of high and low doses of radiation, in large part thanks to the careful study of the survivors of the atomic bombing in Japan, as well as studies of individuals exposed to medical x rays. It is possible to make an estimate, which is probably good to within a factor of, perhaps, three to five, of the cancer risks faced by a patient of a particular age and sex who is going to undergo a particular radiotherapeutic regimen. It is also possible to make an estimate of the risks faced by radiotherapy and nursing staff exposed to low doses. Brachytherapy related risk estimates are likely to be somewhat more uncertain, due to the poorly known sparing effects of the low dose rates used; for the radiotherapy personnel in brachytherapy, because of the doses which can be received, the risks can be quite significant. A recent complication in external-beam radiotherapy is the advent of high-energy linacs, which can produce a significant fast neutron dose which, dose for dose, may be ten to fifty times more carcinogenic than gamma rays. Data relating to the risks of hereditary effects of radiation come almost entirely from laboratory experiments in animals. Studies involving several million mice form the basis of most of our current understanding of hereditary effects. The results of these studies indicate that radiation is a relatively inefficient mutagen. The

  11. Invasive species

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This is a summary of management activities and research related to invasive species on Neal Smith National Wildlife Refuge between 1992 and 2009. As part of the...

  12. Alpha-emitting radioisotopes production for radioimmunotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Chun, Kwon Soo [Korea Institutet of Radiological and Medical Sciences, Seoul (Korea, Republic of)

    2007-02-15

    This review discusses the production of alpha-particle-emitting radionuclides in radioimmunotherapy. Radioimmunotherapy labeled with alpha-particle is expected to be very useful for the treatment of monocellular cancer (e.g. leukemia) and micrometastasis at an early stage, residual tumor remained in tissues after chemotherapy and tumor resection, due to the high linear energy transfer (LET) and the short path length in biological tissue of alpha particle. Despite of the expected effectiveness of alpha-particle in radioimmunotherapy, its clinical research has not been activated by the several reasons, shortage of a suitable a-particle development and a reliable radionuclide production and supply system, appropriate antibody and chelator development. Among them, the establishment of radionuclide development and supply system is a key factor to make an alpha-immunotherapy more popular in clinical trial. Alpha-emitter can be produced by several methods, natural radionuclides, reactor irradiation, cyclotron irradiation, generator system and elution. Due to the sharply increasing demand of {sup 213}Bi, which is a most promising radionuclide in radioimmunotherapy and now has been produced with reactor, the cyclotron production system should be developed urgently to meet the demand.

  13. Colloidal quantum dot light-emitting devices.

    Science.gov (United States)

    Wood, Vanessa; Bulović, Vladimir

    2010-01-01

    Colloidal quantum dot light-emitting devices (QD-LEDs) have generated considerable interest for applications such as thin film displays with improved color saturation and white lighting with a high color rendering index (CRI). We review the key advantages of using quantum dots (QDs) in display and lighting applications, including their color purity, solution processability, and stability. After highlighting the main developments in QD-LED technology in the past 15 years, we describe the three mechanisms for exciting QDs - optical excitation, Förster energy transfer, and direct charge injection - that have been leveraged to create QD-LEDs. We outline the challenges facing QD-LED development, such as QD charging and QD luminescence quenching in QD thin films. We describe how optical downconversion schemes have enabled researchers to overcome these challenges and develop commercial lighting products that incorporate QDs to achieve desirable color temperature and a high CRI while maintaining efficiencies comparable to inorganic white LEDs (>65 lumens per Watt). We conclude by discussing some current directions in QD research that focus on achieving higher efficiency and air-stable QD-LEDs using electrical excitation of the luminescent QDs. PMID:22110863

  14. Colloidal quantum dot light-emitting devices

    Directory of Open Access Journals (Sweden)

    Vanessa Wood

    2010-07-01

    Full Text Available Colloidal quantum dot light-emitting devices (QD-LEDs have generated considerable interest for applications such as thin film displays with improved color saturation and white lighting with a high color rendering index (CRI. We review the key advantages of using quantum dots (QDs in display and lighting applications, including their color purity, solution processability, and stability. After highlighting the main developments in QD-LED technology in the past 15 years, we describe the three mechanisms for exciting QDs – optical excitation, Förster energy transfer, and direct charge injection – that have been leveraged to create QD-LEDs. We outline the challenges facing QD-LED development, such as QD charging and QD luminescence quenching in QD thin films. We describe how optical downconversion schemes have enabled researchers to overcome these challenges and develop commercial lighting products that incorporate QDs to achieve desirable color temperature and a high CRI while maintaining efficiencies comparable to inorganic white LEDs (>65 lumens per Watt. We conclude by discussing some current directions in QD research that focus on achieving higher efficiency and air-stable QD-LEDs using electrical excitation of the luminescent QDs.

  15. Thermally enhanced blue light-emitting diode

    Science.gov (United States)

    Xue, Jin; Zhao, Yuji; Oh, Sang-Ho; Herrington, William F.; Speck, James S.; DenBaars, Steven P.; Nakamura, Shuji; Ram, Rajeev J.

    2015-09-01

    We investigate thermoelectric pumping in wide-bandgap GaN based light-emitting diodes (LEDs) to take advantage of high junction temperature rather than avoiding the problem of temperature-induced efficiency droop through external cooling. We experimentally demonstrate a thermally enhanced 450 nm GaN LED, in which nearly fourfold light output power is achieved at 615 K (compared to 295 K room temperature operation), with nearly no reduction in the wall-plug efficiency (i.e., electrical-optical energy conversion efficiency) at bias V active region by a combination of electrical work and Peltier heat (phonons) drawn from the lattice. In this optimal operating regime at 615 K, the LED injection current (3.26 A/cm2) is of similar magnitude to the operating point of common high power GaN based LEDs (5-35 A/cm2). This result suggests the possibility of removing bulky heat sinks in current high power LED products thus realizing a significant cost reduction for solid-state lighting.

  16. AIR LEVELS OF CARCINOGENIC POLYCYCLIC AROMATIC HYDROCARBONS FOLLOWING THE WORLD TRADE CENTER DISASTER

    Science.gov (United States)

    The catastrophic collapse of the World Trade Center (WTC) on September 11, 2001, created an immense dust cloud followed by fires that emitted soot into the air of New York City (NYC) well into December. The subsequent cleanup used diesel equipment that further polluted the air un...

  17. Monitoring biogenic volatile compounds emitted by Eucalyptus citriodora using SPME.

    Science.gov (United States)

    Zini, C A; Augusto, F; Christensen, T E; Smith, B P; Caramão, E B; Pawliszy, J

    2001-10-01

    A procedure to monitor BVOC emitted by living plants using SPME technique is presented. For this purpose, a glass sampling chamber was designed. This device was employed for the characterization of biogenic volatile compounds emitted by leaves of Eucalyptus citriodora. After extraction with SPME fibers coated with PDMS/ DVB, it was possible to identify or detect 33 compounds emitted by this plant. A semiquantitative approach was applied to monitor the behavior of the emitted BVOC during 9 days. Circadian profiles of the variation in the concentration of isoprene were plotted. Using diffusion-based SPME quantitation, a recently introduced analytical approach, with extraction times as short as 15 s, it was possible to quantify subparts-per-billion amounts of isoprene emitted by this plant. PMID:11605854

  18. Carcinogenic potential of noxious emissions of diesel engines; Potencial cancerigeno de emisiones nocivas en motores a diesel

    Energy Technology Data Exchange (ETDEWEB)

    Romero Lopez, Alejandro F. [Universidad Nacional Autonoma de Mexico, Mexico, D. F. (Mexico)

    1992-12-31

    The carcinogenic effects of the solid particles of carbonaceous nature, generated during the combustion process in the diesel engines, has been a concern of public and private entities in the developed countries, specially during the two last decades. This paper includes a short revision of the recent and preceding publications, found in the technical bibliography. The engine manufacturing enterprises have carried out spectacular changes in the internal design of the diesel engines, to diminish as much as possible, the solid particle generation inside the engine itself. The effort can not come from one part only, also the fuel producing enterprises in developed countries have carried out substantial efforts to improve the fuels as well as the lubricants. The goal of this measures is to practically eliminate the sulfur content, specially in the fuel, since the formation of solid particles linearly depends, among other factors, of this noxious element content in the diesel fuel. Finally, a short discussion is included of some exhaust gases post-treatment systems, that seems to be unavoidable in order to attain the strict standards that for year 1994 and the following years have been established by the Environmental Protection Agency (EPA) of the USA. The Mexican legislation is also analyzed through the Normas Tecnicas Ecologicas (NTE) (Ecological Technical Standards), emitted by the Secretaria de Desarrollo Urbano y Ecologia (SEDUE), now Secretaria de Desarrolo Economico y Social (SEDESOL), simply to have a comparison reference with the international legislation. [Espanol] Los efectos cancerigenos de las particulas solidas de caracter carbonaceo, generadas durante el proceso de combustion de los motores diesel, ha sido preocupacion de organismos publicos y privados en los paises desarrollados, en especial durante las ultimas dos decadas. El trabajo incluye una revision breve de publicaciones recientes y anteriores, que se encuentran en la literatura tecnica. Las

  19. New methods for toxicokinetic studies on chemicals carcinogens by means of analysis of DNA damage

    International Nuclear Information System (INIS)

    For investigating the potential carcinogenic properties of chemicals or for elucidating their mechanisms of activities, it is as important to determine their DNA damaging effects as it is to determine their mutagenicity. In the following, three methods will be presented which may be utilized to detect chemically induced DNA damage. These are the classical DNA filter elution procedure (AE), the in situ nick translation (NT), and the single cell microgel-electrophoresis (MGE) assay. Latter two methods have the advantage that they will allow genotoxic effects to be determined in many organs of the experimental animals, since only minute quantities of tissue are needed. Therefore it is possible to efficiently obtain data pertaining to the toxicokinetics of the test chemical which may be used for purposes of risk assessment. (orig.)

  20. Prepubertal exposure to cow's milk reduces susceptibility to carcinogen-induced mammary tumorigenesis in rats

    DEFF Research Database (Denmark)

    Nielsen, Tina Skau; Khan, Galam; Davis, Jennifer;

    2011-01-01

    Cow's milk contains high levels of estrogens, progesterone and insulin-like growth factor 1 (IGF-1), all of which are associated with breast cancer. We investigated whether prepubertal milk exposure affects mammary gland development and carcinogenesis in rats. Sprague-Dawley rats were given either...... whole milk or tap water to drink from postnatal day (PND) 14 to PND 35, and thereafter normal tap water. Mammary tumorigenesis was induced by administering 7,12-dimethylbenz[a]anthracene on PND 50. Milk exposure increased circulating E2 levels on PND 25 by 10-fold (p < 0.001) and accelerated vaginal...... opening, which marks puberty onset, by 2.5 days (p < 0.001). However, rats exposed to milk before puberty exhibited reduced carcinogen-induced mammary carcinogenesis; that is, their tumor latency was longer (p < 0.03) and incidence was lower (p < 0.05) than in the controls. On PND 25 and 50, mammary...

  1. Role of DNA lesions and DNA repair in mutagenesis by carcinogens in diploid human fibroblasts

    International Nuclear Information System (INIS)

    The authors investigated the cytotoxicity, mutagenicity, and transforming activity of carcinogens and radiation in diploid human fibroblasts, using cells which differ in their DNA repair capacity. The results indicate that cell killing and induction of mutations are correlated with the number of specific lesions remaining unrepaired in the cells at a particular time posttreatment. DNA excision repair acts to eliminate potentially cytotoxic and mutagenic (and transforming) damage from DNA before these can be converted into permanent cellular effects. Normal human fibroblasts were derived from skin biopsies or circumcision material. Skin fibroblasts from xeroderma pigmentosum (XP) patients provided cells deficient in nucleotide excision repair of pyrimidine dimers or DNA adducts formed by bulky ring structures. Cytotoxicity was determined from loss of ability to form a colony. The genetic marker used was resistance to 6-thioguanine (TG). Transformation was measured by determining the frequency of anchorage-independent cells

  2. Evolutionary constraints over microsatellite abundance in larger mammals as a potential mechanism against carcinogenic burden.

    Science.gov (United States)

    Park, Jung Youn; An, Yong-Rock; An, Chul-Min; Kang, Jung-Ha; Kim, Eun Mi; Kim, Heebal; Cho, Seoae; Kim, Jaemin

    2016-01-01

    Larger organisms tend to live longer, have more potentially carcinogenic cells, and undergo more cell divisions. While one might intuitively expect cancer incidence to scale with body size, this assertion does not hold over the range of different mammals. Explaining this lack of correlation, so-called 'Peto's paradox' can likely increase our understanding of how cancer defense mechanisms are shaped by natural selection. Here, we study the occurrence of microsatellite in mammal genomes and observe that animals with expanded body size restrain the number of microsatellite. To take into account of higher mutation rate in the microsatellite region compared to that of genome, limiting the abundance of somatic mutations might explain how larger organisms could overcome the burden of cancer. These observations may serve as the basis to better understand how evolution has modeled protective mechanisms against cancer development. PMID:27125812

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

    DEFF Research Database (Denmark)

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

    2015-01-01

    Bracken ferns are some of the most widespread ferns in the World causing immense problems for land managers, foresters and rangers. Bracken is suspected of causing cancer in Humans due to its content of the carcinogen ptaquiloside. Ingestion of bracken, or food and drinking water contaminated with...... ptaquiloside may be the cause. The aim of this study was to monitor the content of ptaquiloside in 20 bracken stands from Britain to obtain a better understanding of the ptaquiloside dynamics and to evaluate the environmental implications of using different cutting regimes in bracken management. The...... in bracken stands at any given time is difficult to predict and did not show any correlations with edaphic growth factors. The content of ptaquiloside turned out to be higher in fronds emerging after cutting compared to uncut fronds. Environmental risk assessment and bracken management must therefore...

  4. Chlorophyll catalyse the photo-transformation of carcinogenic benzo[a]pyrene in water

    Science.gov (United States)

    Luo, Lijuan; Lai, Xueying; Chen, Baowei; Lin, Li; Fang, Ling; Tam, Nora F. Y.; Luan, Tiangang

    2015-08-01

    Algal blooms cause great damage to water quality and aquaculture. However, this study showed that dead algal cells and chlorophyll could accelerate the photo-transformation of benzo[a]pyrene (BaP), a ubiquitous and persistent pollutant with potently mutagenic and carcinogenic toxicities, under visible light irradiation. Chlorophyll was found to be the major active substance in dead algal cells, and generated a high level of singlet oxygen to catalyse the photo-transformation of BaP. According to various BaP metabolites formed, the degradation mechanism was proposed as that chlorophyll in dead algal cells photo-oxidized BaP to quinones via photocatalytic generation of singlet oxygen. The results provided a good insight into the role of chlorophyll in the photo-transformation of organic contaminants and could be a possible remediation strategy of organic pollutants in natural environment.

  5. Numerical solutions of sheath structures in front of an electron-emitting electrode immersed in a low-density plasma

    Energy Technology Data Exchange (ETDEWEB)

    Din, Alif [Theoretical Plasma Physics Division, PINSTECH, P. O. Nilore, 44000 Islamabad (Pakistan)

    2013-09-15

    The exact theoretical expressions involved in the formation of sheath in front of an electron emitting electrode immersed in a low-density plasma have been derived. The potential profile in the sheath region has been calculated for subcritical, critical, and supercritical emissions. The potential profiles of critical and supercritical emissions reveals that we must take into account a small, instead of zero, electric field at the sheath edge to satisfy the boundary conditions used to integrate the Poisson's equation. The I-V curves for critical emission shows that only high values of plasma-electron to emitted-electron temperature ratio can meet the floating potential of the emissive electrode. A one-dimensional fluid like model is assumed for ions, while the electron species are treated as kinetic. The distribution of emitted-electron from the electrode is assumed to be half Maxwellian. The plasma-electron enters the sheath region at sheath edge with half Maxwellian velocity distribution, while the reflected ones have cut-off velocity distribution due to the absorption of super thermal electrons by the electrode. The effect of varying emitted-electron current on the sheath structure has been studied with the help of a parameter G (the ratio of emitted-electron to plasma-electron densities)

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

    International Nuclear Information System (INIS)

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

  7. Carcinogenicity of deuterium-labeled 1,2-dimethylhydrazine in mice

    International Nuclear Information System (INIS)

    To study the effect of deuterium substitution on the carcinogenicity of 1,2-dimethylhydrazine (DMH) in mice, two comparisons were made between DMH and its fully methyl-deuterated analogue, [2H6]DMH. In a lifetime study with the CBA strain, groups of 19-30 animals of each sex were dosed s.c. weekly with 8 mg/kg of either DMH or [2H6]DMH for 8, 16, or 32 weeks. In the second study, female CF-1 mice were given DMH or [2H6]DMH in 10 weekly s.c. doses of 12 mg/kg each (13.2 mg/kg for [2H6]DMH) and examined for colon tumors 36 weeks after the first dose. Deuteration significantly decreased tumor incidence in the colon of males (P less than 0.01) and the anal tissue of both sexes (P less than 0.05) but increased that of hepatomas and lung tumors in males (P less than 0.01). Substrate deuteration did not significantly affect overall incidence of any other tumor type, however, including hemangioendotheliomas and kidney tumors in both sexes, as well as colon, uterine, ovarian, liver, and lung tumors in females. The results indicate that C--H bond breakage is kinetically important in the activation of DMH to its ultimately carcinogenic form in organs such as the male colon (relative risk in DMH-versus [2H6]DMH-treated animals approximately equal to 6), and that inhibition of this process by substrate deuteration allows a diversionary mechanism having a smaller isotope effect to become relatively more extensive. The qualitatively different effect in other organs (e.g., kidney, relative risk approximately equal to 1) supports recent suggestions that the net mechanism of activation can differ from one target tissue to another, possibly by striking a different balance between parallel metabolic pathways

  8. Toxicogenomic approaches for understanding molecular mechanisms of heavy metal mutagenicity and carcinogenicity.

    Science.gov (United States)

    Koedrith, Preeyaporn; Kim, Hyelim; Weon, Jong-Il; Seo, Young Rok

    2013-08-01

    Heavy metals that are harmful to humans include arsenic, cadmium, chromium, lead, mercury, and nickel. Some metals or their related compounds may even cause cancer. However, the mechanism underlying heavy metal-induced cancer remains unclear. Increasing data show a link between heavy metal exposure and aberrant changes in both genetic and epigenetic factors via non-targeted multiple toxicogenomic technologies of the transcriptome, proteome, metabolome, and epigenome. These modifications due to heavy metal exposure might provide a better understanding of environmental disorders. Such informative changes following heavy metal exposure might also be useful for screening of biomarker-monitored exposure to environmental pollutants and/or predicting the risk of disease. We summarize advances in high-throughput toxicogenomic-based technologies and studies related to exposure to individual heavy metal and/or mixtures and propose the underlying mechanism of action and toxicant signatures. Integrative multi-level expression analysis of the toxicity of heavy metals via system toxicology-based methodologies combined with statistical and computational tools might clarify the biological pathways involved in carcinogenic processes. Although standard in vitro and in vivo endpoint testing of mutagenicity and carcinogenicity are considered a complementary approach linked to disease, we also suggest that further evaluation of prominent biomarkers reflecting effects, responses, and disease susceptibility might be diagnostic. Furthermore, we discuss challenges in toxicogenomic applications for toxicological studies of metal mixtures and epidemiological research. Taken together, this review presents toxicogenomic data that will be useful for improvement of the knowledge of carcinogenesis and the development of better strategies for health risk assessment. PMID:23540489

  9. Biomonitoring of complex occupational exposures to carcinogens: The case of sewage workers in Paris

    International Nuclear Information System (INIS)

    Sewage workers provide an essential service in the protection of public and environmental health. However, they are exposed to varied mixtures of chemicals; some are known or suspected to be genotoxics or carcinogens. Thus, trying to relate adverse outcomes to single toxicant is inappropriate. We aim to investigate if sewage workers are at increased carcinogenic risk as evaluated by biomarkers of exposure and early biological effects. This cross sectional study will compare exposed sewage workers to non-exposed office workers. Both are voluntaries from Paris municipality, males, aged (20–60) years, non-smokers since at least six months, with no history of chronic or recent illness, and have similar socioeconomic status. After at least 3 days of consecutive work, blood sample and a 24-hour urine will be collected. A caffeine test will be performed, by administering coffee and collecting urines three hours after. Subjects will fill in self-administered questionnaires; one covering the professional and lifestyle habits while the a second one is alimentary. The blood sample will be used to assess DNA adducts in peripheral lymphocytes. The 24-hour urine to assess urinary 8-oxo-7, 8-dihydro-2'-deoxy-Guanosine (8-oxo-dG), and the in vitro genotoxicity tests (comet and micronucleus) using HeLa S3 or HepG2 cells. In parallel, occupational air sampling will be conducted for some Polycyclic Aromatic Hydrocarbons and Volatile Organic Compounds. A weekly sampling chronology at the offices of occupational medicine in Paris city during the regular medical visits will be followed. This protocol has been accepted by the French Est III Ethical Comitee with the number 2007-A00685-48. Biomarkers of exposure and of early biological effects may help overcome the limitations of environmental exposure assessment in very complex occupational or environmental settings

  10. Carcinogenicity study of ammonia-process caramel in F344 rats.

    Science.gov (United States)

    Maekawa, A; Ogiu, T; Matsuoka, C; Onodera, H; Furuta, K; Tanigawa, H; Hayashi, Y; Odashima, S

    1983-06-01

    The carcinogenicity of ammonia-process caramel, a food colouring, was examined in F344 rats. Caramel was dissolved in distilled water at levels of 0, 1 and 4% and groups of 50 male and 50 female rats were given 20-25 ml of one of these solutions/rat/day as their drinking water for 2 yr. There were no significant differences between the total incidences of tumours or mean survival times of control and experimental groups. A variety of tumours developed in all groups including the control group, and no dose-related effects were found either in the incidence or induction time of tumours in the various organs and tissues except in the pituitary gland of males, in which the incidence of tumours in males given 4% caramel solution was significantly higher than that in controls. Pituitary tumours are among the most common spontaneous tumours in ageing rats of this strain and have a variable incidence. In addition, almost all pituitary tumours detected in males given the 4% solution were microscopic tumours, and there was no significant difference between controls and treated groups in the incidence of hyperplasia or pre-neoplastic lesions in the pituitary gland. These results indicate that the significantly higher incidence of pituitary tumours in males given the 4% caramel solution was not related to caramel administration, but could be explained by the variability of the incidence of spontaneous pituitary tumours. Thus it is concluded that under these experimental conditions ammonia-process caramel was not carcinogenic in F344 rats. PMID:6683219

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

    International Nuclear Information System (INIS)

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

  12. The carcinogenic risks of low-LET and high-LET ionizing radiations

    International Nuclear Information System (INIS)

    New information is available concerning the carcinogenic effects of radiation and the implications for risk assessment and risk management. This information comes from further follow-up of the epidemiological studies of the Japanese atomic bomb survivors, patients irradiated medically for cancer and allied conditions, and workers exposed in various occupations. In the Japanese atomic bomb survivors the carcinogenic risks are estimated to be somewhat higher than previously, due to the reassessment of the atomic-bomb dosimetry, further follow-up with increase in the number of excess cancer deaths, particularly in survivors irradiated early in life, and changes in the methods of analysis to compute the age-specific risks of cancer. Because of the characteristics of the atomic bomb survivor series as regards sample size, age and sex distribution, duration for follow-up, person-years at risk, and type of dosimetry, the mortality experience of the atomic bomb survivors was selected by the UNSCEAR Committee and the BEIR V Committee as the more appropriate basis for projecting risk estimates for the general population. In the atomic bomb survivors, the dose-effect relationship for overall cancer mortality other than leukemia is consistent with linearity below 3 Gy, while the dose-effect relationship for leukemia, excluding chronic lymphatic leukemia, conforms best to a linear-quadratic function. The shape of the dose-incidence curve at low doses still remains uncertain, and the data do not rule out the possible existence of a threshold for an neoplasm. The excess relative risk of mortality from all cancers combined is estimated to be 1.39 per Gy (shielded kerma), which corresponds to an absolute risk of 10.0 excess cancer deaths per 10,000 PYGy; the relative risks is 1.41 at 1 Gy (organ-absorbed dose), and an absolute risk of 13.07 excess cancer deaths per 10,000 PYGy. 19 refs

  13. Light dependency of VOC emissions from selected Mediterranean plant species

    Science.gov (United States)

    Owen, S. M.; Harley, P.; Guenther, A.; Hewitt, C. N.

    The light, temperature and stomatal conductance dependencies of volatile organic compound (VOC) emissions from ten plant species commonly found in the Mediterranean region were studied using a fully controlled leaf cuvette in the laboratory. At standard conditions of temperature and light (30°C and 1000 μmol m -2 s -1 PAR), low emitting species ( Arbutus unedo, Pinus halepensis, Cistus incanus, Cistus salvifolius, Rosmarinus officinalis and Thymus vulgaris) emitted between 0.1 and 5.0 μg (C) (total VOCs) g -1 dw h -1, a medium emitter ( Pinus pinea) emitted between 5 and 10 μg (C) g -1 dw h -1 and high emitters ( Cistus monspeliensis, Lavendula stoechas and Quercus sp.) emitted more than 10 μg (C) g -1 dw h -1. VOC emissions from all of the plant species investigated showed some degree of light dependency, which was distinguishable from temperature dependency. Emissions of all compounds from Quercus sp. were light dependent. Ocimene was one of several monoterpene compounds emitted by P. pinea and was strongly correlated to light. Only a fraction of monoterpene emissions from C. incanus exhibited apparent weak light dependency but emissions from this plant species were strongly correlated to temperature. Data presented here are consistent with past studies, which show that emissions are independent of stomatal conductance. These results may allow more accurate predictions of monoterpene emission fluxes from the Mediterranean region to be made.

  14. Blue emitting fluorophores of phenyleneethynylenes substituted by diphenylethenyl terminal groups for organic light-emitting diodes

    International Nuclear Information System (INIS)

    Phenyleneethynylene motifs substituted by diphenylethenyl groups at both ends were prepared successfully by use of double elimination protocol of β-substituted sulfones for introducing phenyleneethynylene arrays followed by Wittig-Horner reaction for introducing diphenylethenyl moiety. The hybrid blue fluorophores exhibited strong emission even in the solid-state films (ΦF ≥ 0.60) while, in CHCl3 solution, incorporation of substituents on the central phenylene unit significantly enhanced emission efficiency up to ΦF = 0.57. The OLED devices with use of these blue fluorophores as an emitting material provided maximum external quantum efficiency of ηext = 2.4%

  15. SEROLOGICAL ALTERATIONS IN CARCINOGEN-EXPOSED TELEOSTS: PROCEDURES FOR PREPARATION AND ANALYSIS OF SAMPLES FROM SMALL FISH

    Science.gov (United States)

    To study the effects of environmental carcinogens on the immune system of Cyprinodon variegatus, the authors had to miniaturize or modify standard immunological procedures due to the small size of the fish. Modifications in standard bleeding procedures allowed collection of suffi...

  16. Human cytochrome P450 enzymes of importance for the bioactivation of methyleugenol to the proximate carcinogen 1′-hydroxymethyleugenol

    NARCIS (Netherlands)

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

    2006-01-01

    In vitro studies were performed to elucidate the human cytochrome P450 enzymes involved in the bioactivation of methyleugenol to its proximate carcinogen 1′-hydroxymethyleugenol. Incubations with Supersomes, expressing individual P450 enzymes to a high level, revealed that P450 1A2, 2A6, 2C9, 2C19,

  17. Effects of combined exposure of F344 rats to inhaled Plutonium-239 dioxide and a chemical carcinogen (NNK)

    Energy Technology Data Exchange (ETDEWEB)

    Lundgren, D.L.; Carlton, W.W. [Purdue Univ., Lafayette, IN (United States); Griffith, W.C. [and others

    1995-12-01

    Workers in nuclear weapons facilities have a significant potential for exposure to chemical carcinogens and to radiation from external sources or from internally deposited radionuclides such as {sup 239}Pu. Although the carcinogenic effects of inhaled {sup 239}Pu and many chemicals have been studied individually, very little information is available on their combined effects. One chemical carcinogen that workers could be exposed to via tobacco smoke is the tobacco-specific nitrosamine 4-(N-methyl-n-nitrosamino)-1-(3-pyridyl)-1(3-pyridyl)-1-butanone (NNK), a product of tobacco curing and the pyrolysis of nicotine in tobacco. NNK causes lung tumors in rats, regardless of the route of administration and to a lesser extent liver, nasal, and pancreatic tumors. From the results presented, it can be concluded that exposure to a chemical carcinogen (NNK) in combination with {alpha}-particle radiation from inhaled {sup 239}PuO{sub 2} acts in, at best, an additive manner in inducing lung cancer in rats.

  18. An investigation on the physical, chemical and ecotoxicological characteristics of particulate matter emitted from light-duty vehicles

    International Nuclear Information System (INIS)

    Particulate matter (PM) emitted from three light-duty vehicles was studied in terms of its physicochemical and ecotoxicological character using Microtox bioassay tests. A diesel vehicle equipped with an oxidation catalyst emitted PM which consisted of carbon species at over 97%. PM from a diesel vehicle with a particle filter (DPF) consisted of almost equal amounts of carbon species and ions, while a gasoline vehicle emitted PM consisting of ∼90% carbon and ∼10% ions. Both the DPF and the gasoline vehicles produced a distinct nucleation mode at 120 km/h. The PM emitted from the DPF and the gasoline vehicles was less ecotoxic than that of conventional diesel, but not in direct proportion to the emission levels of the different vehicles. These results indicate that PM emission reductions are not equally translated into ecotoxicity reductions, implying some deficiencies on the actual environmental impact of emission control technologies and regulations. - PM emission reductions brought by more stringent emission standards and associated technologies may not lead to equivalent (eco-)toxicity reductions.

  19. Power output and efficiency of beta-emitting microspheres

    Science.gov (United States)

    Cheneler, David; Ward, Michael

    2015-01-01

    Current standard methods to calculate the dose of radiation emitted during medical applications by beta-minus emitting microspheres rely on an over-simplistic formalism. This formalism is a function of the average activity of the radioisotope used and the physiological dimensions of the patient only. It neglects the variation in energy of the emitted beta particle due to self-attenuation, or self-absorption, effects related to the finite size of the sphere. Here it is assumed the sphere is comprised of a pure radioisotope with beta particles being emitted isotropically throughout the material. The full initial possible kinetic energy distribution of a beta particle is taken into account as well as the energy losses due to scattering by other atoms in the microsphere and bremsstrahlung radiation. By combining Longmire's theory of the mean forward range of charged particles and the Rayleigh distribution to take into account the statistical nature of scattering and energy straggling, the linear attenuation, or self-absorption, coefficient for beta-emitting radioisotopes has been deduced. By analogy with gamma radiation transport in spheres, this result was used to calculate the rate of energy emitted by a beta-emitting microsphere and its efficiency. Comparisons to standard point dose kernel formulations generated using Monte Carlo data show the efficacy of the proposed method. Yttrium-90 is used as a specific example throughout, as a medically significant radioisotope, frequently used in radiation therapy for treating cancer.

  20. AC Impedance Studies of Polymer Light-emitting Electrochemical Cells and Light-emitting Diodes

    Science.gov (United States)

    Li, Yongfang; Gao, Jun; Heeger, Alan J.; Yu, Gang; Cao, Yong

    1998-03-01

    The alternating current (ac) impedance of polymer light-emitting electrochemical cells (LECs) is studied and compared with that of polymer light-emitting diodes(LEDs) in the frequency range from 100 Hz to 5 M Hz. The device capacitance, resistance and interface characteristics are analyzed using the frequency dependence of the impedance and plots of the imaginary component of the impedance (Z") vs. the real part (Z'). At low bias voltages, polymer LEDs behave as pure capacitors whereas the polymer blend in the LEC exhibits an ionic conductivity contribution to the impedance. With dc bias higher than the energy gap of the semiconducting polymer (eV > Eg), the Z" vs. Z' plot of the LEC is a flattened semicircle, while that of LED is a semicircle with a small tail at low frequencies. In the LED, the capacitance is independent of voltages, the film resistance decreases as the bias voltage is increased in forward bias due to charge injection at higher voltages. In the LEC, the capacitance increases at voltages sufficient to induce electrochemical redox and doping near the electrodes. From this increase, the thickness of the i-layer of the p-i-n junction is estimated to approximately 0.8 of the film thickness (at the bias voltage of 3 V). Thus, in the LEC under operating conditions, the crossover region from p-type occupies most of the film thickness.

  1. Synthesis and Property of New Propeller Shaped Emitting Materials for Organic Light-Emitting Devices.

    Science.gov (United States)

    Kang, Seokwoo; Lee, Hayoon; Kim, Beomjin; Park, Youngil; Park, Jongwook

    2016-03-01

    New propeller type emitting compound, namely 3,6-di-anthracen-9-yl-9,10-bis-(4-anthracen-9-yi-phenyl)-phenanthrene[TAnDAP] and 3,6-bis-(10-phenyl-anthracen-9-yl)-9,10-bis-[4-(10-phenyl-anthracen-9-yl)-phenyl]-phenanthrene [TAnPDAP] were synthesized through Suzuki and McMurry reactions. We investigated their physical properties such as optical, electrochemical, and electroluminescent properties. The two compounds were used as an emitting layer in OLED devices: ITO/2-TNATA (60 nm)/NPB (15 nm)/non-doped: TAnDAP or TAnPDAP (35 nm)/Alq3 (20 nm)/LiF (1 nm)/Al (200 nm). The TAnDAP OLED device showed C.I.E. value of (0.28, 0.41) and luminance efficiency of 3.81 cd/A at 10 mA/cm2. The TAnPDAP device showed C.I.E. value of (0.20, 0.27) and high luminance efficiency of 5.40 cd/A at 10 mA/cm2. TAnPDAP was found to show better luminance efficiency and C.I.E. value than TAnDAP because it has a bulky 9-phenylanthracene. PMID:27455768

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

    International Nuclear Information System (INIS)

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

  3. Power output and efficiency of beta-emitting microspheres

    OpenAIRE

    Cheneler, David; Ward, Michael C L

    2015-01-01

    Current standard methods to calculate the dose of radiation emitted during medical applications by beta-minus emitting microspheres rely on an over-simplistic formalism. This formalism is a function of the average activity of the radioisotope used and the physiological dimensions of the patient only. It neglects the variation in energy of the emitted beta particle due to self-attenuation, or self-absorption, effects related to the finite size of the sphere. Here it is assumed the sphere is co...

  4. Plant Growth Under Light Emitting Diode Irradiation.

    Science.gov (United States)

    Tennessen, Daniel John

    Plant growth under light emitting diodes (LEDs) was investigated to determine if LEDs would be useful to provide radiant energy for two plant processes, photosynthesis and photomorphogenesis. Photosynthesis of tomato (Lycopersicon esculentum L.) and Kudzu (Pueraria lobata (Willd) Ohwi.) was measured using photons from LEDs to answer the following: (1) Are leaves able to use red LED light for photosynthesis? and (2) Is the efficiency of photosynthesis in pulsed light equal to that of continuous light? In 175 Pa CO _2, or in response to changes in CO _2,photosynthesis and ATP status were the same in LED as in white xenon arc light. In 35 Pa CO_2, photosynthesis was 10% lower in LED than in xenon arc light due to lowered stomatal conductance. The quantum efficiency of photosynthesis in pulsed light was equal to continuous light, even when pulses were twice as bright as sunlight. Xanthophyll pigments were not affected by these bright pulses. Photomorphogenesis of tobacco (Nicotiana tabacum L.), tomato (Lycopersicon esculentum Mill.) and transformed tobacco and tomato (expressing oat phytochrome-A) was assessed by growing plants under red LED lamps in an attempt to answer the following: (1) What is the developmental response of non-transformed and transformed tobacco to red LED light? and (2) Can tomato plants that grow tall and spindly in red LED light be made to grow short by increasing the amount of phytochrome-A? The short phenotype of transformed tobacco was not evident when plants were grown in LED light. Addition of photons of far-red or blue light to red light resulted in short transformed tobacco. Tomato plants grew three times as tall and lacked leaf development in LED versus white light, but transformed tomato remained short and produced fruit under LED light. I have determined that the LED photons are useful for photosynthesis and that the photon efficiency of photosynthesis is the same in pulsed as in continuous light. From responses of tobacco, I concluded

  5. Encapsulation of organic light emitting diodes

    Science.gov (United States)

    Visweswaran, Bhadri

    Organic Light Emitting Diodes (OLEDs) are extremely attractive candidates for flexible display and lighting panels due to their high contrast ratio, light weight and flexible nature. However, the materials in an OLED get oxidized by extremely small quantities of atmospheric moisture and oxygen. To obtain a flexible OLED device, a flexible thin-film barrier encapsulation with low permeability for water is necessary. Water permeates through a thin-film barrier by 4 modes: microcracks, contaminant particles, along interfaces, and through the bulk of the material. We have developed a flexible barrier film made by Plasma Enhanced Chemical Vapor Deposition (PECVD) that is devoid of any microcracks. In this work we have systematically reduced the permeation from the other three modes to come up with a barrier film design for an operating lifetime of over 10 years. To provide quantitative feedback during barrier material development, techniques for measuring low diffusion coefficient and solubility of water in a barrier material have been developed. The mechanism of water diffusion in the barrier has been identified. From the measurements, we have created a model for predicting the operating lifetime from accelerated tests when the lifetime is limited by bulk diffusion. To prevent the particle induced water permeation, we have encapsulated artificial particles and have studied their cross section. A three layer thin-film that can coat a particle at thicknesses smaller than the particle diameter is identified. It is demonstrated to protect a bottom emission OLED device that was contaminated with standard sized glass beads. The photoresist and the organic layers below the barrier film causes sideways permeation that can reduce the lifetime set by permeation through the bulk of the barrier. To prevent the sideways permeation, an impermeable inorganic grid made of the same barrier material is designed. The reduction in sideways permeation due to the impermeable inorganic grid

  6. Top-emitting quantum dots light-emitting devices employing microcontact printing with electricfield-independent emission

    OpenAIRE

    Shihao Liu; Wenbo Liu; Wenyu Ji; Jing Yu; Wei Zhang; Letian Zhang; Wenfa Xie

    2016-01-01

    Recent breakthroughs in quantum dot light-emitting devices (QD-LEDs) show their promise in the development of next-generation displays. However, the QD-LED with conventional ITO-based bottom emission structure is difficult to realize the high aperture ratio, electricfield-independent emission and flexible full-color displays. Hence, we demonstrate top-emitting QD-LEDs with dry microcontact printing quantum dot films. The top-emitting structure is proved to be able to accelerate the excitons r...

  7. White top emitting OLED with angle independent emission characteristic

    Energy Technology Data Exchange (ETDEWEB)

    Thomschke, Michael; Freitag, Patricia; Schwartz, Gregor; Nitsche, Robert; Walzer, Karsten; Leo, Karl [Technische Universitaet Dresden, Institut fuer Angewandte Photophysik, Georg-Baehr-Strasse 1, 01062 Dresden (Germany)

    2008-07-01

    The general device structure of a top emitting organic light emitting diode (OLED) consists of several organic layers sandwiched in between two metal contacts, with the top one being semitransparent for light outcoupling reasons. Due to the high reflectivity of the electrodes, strong microcavity effects occur which lead to a preferred emission of light of a certain wavelength with main outcoupling in forward direction. This creates rather narrow emission bands, accompanied by strong spectral shifts upon viewing angle variation. By using an organic capping layer on top of the semitransparent metal contact, this unwanted effect can be reduced. This is important especially for white light emission for the use of OLEDs in future lighting applications. Our optical simulations show that the strong angular dependence of the emission color almost vanishes. To verify the simulations we study white top emitting OLEDs based on an approach which are adapted to the top emitting case.

  8. Organotellurium-mediated living radical polymerization under photoirradiation by a low-intensity light-emitting diode

    OpenAIRE

    Yasuyuki Nakamura; Shigeru Yamago

    2013-01-01

    A low-intensity (6 W) light-emitting diode (LED) effectively activated an organotellurium chain transfer agent and the dormant species, promoting well-controlled radical polymerization. The use of the LED provided many advantages over the previously reported high-intensity Hg lamp, including high energy efficiency during the polymerization, and easy availability of the low-cost light source. Structurally well-defined poly(methyl methacrylate), poly(methyl acrylate), and polystyrene, with narr...

  9. Human health risk due to consumption of vegetables contaminated with carcinogenic polycyclic aromatic hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Sardar [Chinese Academy of Sciences, Xiamen (China). Inst. of Urban Environment; Peshawar Univ. (Pakistan). Dept. of Environmental Science; Cao, Qing [Chinese Academy of Sciences, Beijing (China). Research Center for Eco-Environemntal Sciences

    2012-02-15

    Polycyclic aromatic hydrocarbons (PAH) are persistent, toxic, and carcinogenic contaminants present in soil ecosystem globally. These pollutants are gradually accumulating in wastewater-irrigated soils and lead to the contamination of vegetables. Food chain contamination with PAH is considered as one of the major pathways for human exposure. This study was aimed to investigate the concentrations of PAH in soils and vegetables collected from wastewater-irrigated fields from metropolitan areas of Beijing, China. Origin of PAH, daily intake, and health risks of PAH through consumption of contaminated vegetables were studied. Soil samples were collected from the upper horizon (0-20 cm) of both wastewater-irrigated and reference sites and sieved (<2 mm mesh) and then followed by freeze-drying at -50 C and 123 {+-} 2 Pa. Standing vegetables were also collected from the same sites used for soil sampling and divided into roots and shoots, thoroughly washed with deionized water, and freeze-dried. PAH were extracted using the Soxhlet method with 200 mL DCM for 24 h, and the extracts were cleaned with silica adsorption chromatography prepared with silica gel, alumina, and capped with anhydrous sodium. The final concentrated extracts (soil and vegetable) were analyzed using gas chromatography-mass spectrometry (Agilent 6890). Bioaccumulation factors, daily intake of PAH, and carcinogenicity of PAH were calculated by different statistical equations. Results indicate that the soils and grown vegetables were contaminated with all possible carcinogenic PAH (declared by USEPA 2002) except indeno[1,2,3-c,d]pyrene. The highest concentration (242.9 {mu}g kg{sup -1}) was found for benzo(k)fluoranthene (BkF), while lowest (79.12 {mu}g kg{sup -1}) for benzo[a]pyrene (BaP). The emission sources of PAH were both pyrogenic and petrogenic in nature. However, the total concentrations of PAH were lower than the permissible limits set by different countries like Canada, Denmark and Germany

  10. A combined chronic toxicity/carcinogenicity study of sucralose in Sprague-Dawley rats.

    Science.gov (United States)

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

    2000-01-01

    The chronic toxicity and potential carcinogenicity of sucralose was evaluated by exposing Sprague-Dawley rats to dietary concentrations of this low-calorie sweetener both in utero and for up to 104 weeks following parturition. The rats assigned to the toxicity phase of this investigation were administered diets containing either 0% (control), 0.3% (3000 ppm), 1.0% (10,000 ppm) or 3.0% (30,000 ppm) sucralose. Each treatment group comprised 30 male and 30 female rats, of which 15 males and 15 females were sacrificed after 52 weeks of treatment. The surviving rats were killed following 78 weeks of sucralose administration. In the carcinogenicity phase of this investigation, groups of 50 male and 50 female rats were administered dietary sucralose at concentrations of 0% (control 1), 0% (control 2), 0.3%, 1.0% or 3.0% for 104 weeks. Evaluation of the data obtained from the two phases of this study showed that sucralose was not carcinogenic. Sucralose did not adversely affect the survival or clinical condition of the rats, and there were no toxicologically significant findings. Group mean body weight gain and food consumption were significantly decreased in a dose-dependent manner in sucralose-treated rats throughout the treatment period as compared to the controls. The primary effect of sucralose on food consumption, and secondarily on body weight gain, was established in later studies to be due to the fact that diets containing high concentrations of sucralose are unpalatable to rats. These subsequent studies established that the reduction of body weight gain seen in previous rat studies using sucralose in the diet at concentrations of 1% and below resulted from reduced food intake as a direct consequence of the unpalatable nature of sucralose. Similarly, at concentrations of 3% in the diet, it was shown that approximately 95% of the effect on body weight gain could be attributed to the reduction in food intake due to the reduced palatability of the diet, the remainder

  11. SOR/72-43 Radiation Emitting Devices Regulations

    International Nuclear Information System (INIS)

    These Regulations of 10 February 1972, supplemented by SOR/77-895, lay down the classes of radiation emitting devices for the purposes of the Radiation Emitting Devices Act. They lay down their standards of design and construction and warning sign specifications and provide for the procedure to be followed by inspectors of such devices. The devices include inter alia extra-oral dental x-ray equipment, baggage inspection x-ray devices, laser scanners, television receivers. (NEA)

  12. Power output and efficiency of beta-emitting microspheres

    International Nuclear Information System (INIS)

    Current standard methods to calculate the dose of radiation emitted during medical applications by beta-minus emitting microspheres rely on an over-simplistic formalism. This formalism is a function of the average activity of the radioisotope used and the physiological dimensions of the patient only. It neglects the variation in energy of the emitted beta particle due to self-attenuation, or self-absorption, effects related to the finite size of the sphere. Here it is assumed the sphere is comprised of a pure radioisotope with beta particles being emitted isotropically throughout the material. The full initial possible kinetic energy distribution of a beta particle is taken into account as well as the energy losses due to scattering by other atoms in the microsphere and bremsstrahlung radiation. By combining Longmire’s theory of the mean forward range of charged particles and the Rayleigh distribution to take into account the statistical nature of scattering and energy straggling, the linear attenuation, or self-absorption, coefficient for beta-emitting radioisotopes has been deduced. By analogy with gamma radiation transport in spheres, this result was used to calculate the rate of energy emitted by a beta-emitting microsphere and its efficiency. Comparisons to standard point dose kernel formulations generated using Monte Carlo data show the efficacy of the proposed method. Yttrium-90 is used as a specific example throughout, as a medically significant radioisotope, frequently used in radiation therapy for treating cancer. - Highlights: • Range-energy relationship for the beta particles in yttrium-90 is calculated. • Formalism for the semi-analytical calculation of self-absorption coefficients. • Energy-dependent self-absorption coefficient calculated for yttrium-90. • Flux rate of beta particles from a self-attenuating radioactive sphere is shown. • The efficiency of beta particle emitting radioactive microspheres is calculated

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

    Science.gov (United States)

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

    2010-01-15

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

  14. Simulation of mixed-host emitting layer based organic light emitting diodes

    Science.gov (United States)

    Riku, C.; Kee, Y. Y.; Ong, T. S.; Yap, S. S.; Tou, T. Y.

    2015-04-01

    `SimOLED' simulator is used in this work to investigate the efficiency of the mixed-host organic light emitting devices (MH-OLEDs). Tris-(8-hydroxyquinoline) aluminum(3) (Alq3) and N,N-diphenyl-N,N-Bis(3-methylphenyl)-1,1-diphenyl-4,4-diamine (TPD) are used as the electron transport layer (ETL) material and hole transport layer (HTL) material respectively, and the indium-doped tin oxide (ITO) and aluminum (Al) as anode and cathode. Three MH-OLEDs, A, B and C with the same structure of ITO / HTM (15 nm) / Mixed host (70 nm) / ETM (10 nm) /Al, are stimulated with ratios TPD:Alq3 of 3:5, 5:5, and 5:3 respectively. The Poole-Frenkel model for electron and hole mobilities is employed to compute the current density-applied voltage-luminance characteristics, distribution of the electric field, carrier concentrations and recombination rate.

  15. Low driving voltage in white organic light-emitting diodes using an interfacial energy barrier free multilayer emitting structure

    International Nuclear Information System (INIS)

    The driving voltage of white organic light-emitting diodes (WOLEDs) with blue fluorescent and red phosphorescent emitting materials was lowered by using a device architecture with little energy barrier between emitting layers. A mixed layer of hole and electron transport materials was used as a host material and an interlayer, reducing the driving voltage of WOLEDs. The driving voltage of WOLEDs was reduced by more than 4 V and power efficiency of WOLEDs was improved by more than 40% due to little energy barrier for holes and electrons injection in light-emitting layer. In addition, there was little change of electroluminescence spectra from 100 to 10,000 cd/m2.

  16. Color tuning of light-emitting-diodes by modulating the concentration of red-emitting silicon nanocrystal phosphors

    International Nuclear Information System (INIS)

    Luminescent forms of nanostructured silicon have received significant attention in the context of quantum-confined light-emitting devices thanks to size-tunable emission wavelength and high-intensity photoluminescence, as well as natural abundance, low cost, and non-toxicity. Here, we show that red-emitting silicon nanocrystal (SiN) phosphors, obtained by electrochemical erosion of silicon, allow for effectively tuning the color of commercial light-emitting-diodes (LEDs) from blue to violet, magenta, and red, by coating the LED with polydimethylsiloxane encapsulating different SiN concentrations. High reliability of the tuning process, with respect to SiN fabrication and concentration, and excellent stability of the tuning color, with respect to LED bias current, is demonstrated through simultaneous electrical/optical characterization of SiN-modified commercial LEDs, thus envisaging exciting perspectives for silicon nanocrystals in the field of light-emitting applications

  17. Covalent binding of food carcinogens MeIQx, MeIQ and IQ to DNA and protein in microsomal incubations and isolated rat hepatocytes

    Energy Technology Data Exchange (ETDEWEB)

    Wallin, H.; Holme, J.A.; Alexander, J. (National Institute of Public Health, Department of Environmental Medicine, Oslo (Norway))

    1992-01-01

    The metabolic activation of {sup 14}C-labelled food carcinogens 2-amino-3,8-dimethylimidazo(4,5-f)quinoxaline (MeIQx),2-amino-3,4-dimethylimidazo(4,5-f)quinoline(MeIQ) and 2-amino-3-methylimidazo(4,5-f)quinoline (IQ) to macromolecular bound species was studied in microsomal and hepatocellular incubations. Several data indicated that the covalent binding was dependent on P450 enzymes: It was dependent on NADPH, it was induced many times by the P450 IA1 and IA2 upregulators {beta}-naphthoflavone and polychlorinated biphenyls, and was inhibited by the P450 IA1 and IA2 inhibitor {alpha}-naphtoflavone. In both hepatocellular and microsomal incubations the three compounds bound with similar efficiency, with IQ being somewhat more potent compared to MeIQx and MeIQ. The binding appeared to follow saturation kinetics with K{sub m} values less than 20 {mu}M. In incubations with hepatocytes the compounds bound to both cellular DNA and to bovine serum albumin in the medium. The fact that 13-26% of total adducts were formed with bovine serum albumin, indicates that reactive metabolites of the compounds may be transported and react at distant sites from their formation without any further activation. (au).

  18. Covalent binding of food carcinogens MeIQx, MeIQ and IQ to DNA and protein in microsomal incubations and isolated rat hepatocytes

    International Nuclear Information System (INIS)

    The metabolic activation of 14C-labelled food carcinogens 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx),2-amino-3,4-dimethylimidazo[4,5-f]quinoline(MeIQ) and 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) to macromolecular bound species was studied in microsomal and hepatocellular incubations. Several data indicated that the covalent binding was dependent on P450 enzymes: It was dependent on NADPH, it was induced many times by the P450 IA1 and IA2 upregulators β-naphthoflavone and polychlorinated biphenyls, and was inhibited by the P450 IA1 and IA2 inhibitor α-naphtoflavone. In both hepatocellular and microsomal incubations the three compounds bound with similar efficiency, with IQ being somewhat more potent compared to MeIQx and MeIQ. The binding appeared to follow saturation kinetics with Km values less than 20 μM. In incubations with hepatocytes the compounds bound to both cellular DNA and to bovine serum albumin in the medium. The fact that 13-26% of total adducts were formed with bovine serum albumin, indicates that reactive metabolites of the compounds may be transported and react at distant sites from their formation without any further activation. (au)

  19. The value of probabilistic modelling for the estimation of carcinogenic risk at low doses. Application to 2, 3, 7, 8-Tetrachlorodibenzo-p-dioxin (TCDD)

    International Nuclear Information System (INIS)

    The two main different approaches for the determination of carcinogenic risk at low doses of exposure to chemicals are presented, i.e. the threshold model based on the No-Observed-Effect-Level (NOEL) and the non-threshold assumption based on the probabilistic modelling of data. Three statistical models based on the distribution of tolerances in the population are presented and applied to TCDD: Probit, Logit and Extreme-Value model. Two mechanistic models based on assumptions concerning the mechanism of carcinogenesis are presented likewise: the One-Hit and the MultiStage models. Probabilistic modelling present numerous advantages as far as the comparison of risks of chemicals is concerned since it allows for: i) a better characterisation of uncertainty; ii) a comparison of chemicals between themselves for a given model; iii) a comparison of chemicals between themselves for a given model; iii) a comparison of species for a given model; iv) the explicitation of one's preference in the choice of the model and its attributes; v) the explicitation of the accepted excess risk as a basis for decision-making. (author)

  20. Identification and quantitation of volatile organic compounds emitted from dairy silages and other feedstuffs.

    Science.gov (United States)

    Malkina, Irina L; Kumar, Anuj; Green, Peter G; Mitloehner, Frank M

    2011-01-01

    High ground-level ozone continues to be an important human, animal, and plant health impediment in the United States and especially in California's San Joaquin Valley (SJV). According to California state and regional air quality agencies, dairies are one of the major sources of volatile organic compounds (VOCs) in the SJV. A number of recently conducted studies reported emissions data from different dairy sources. However, limited data are currently available for silage and otherfeed storages on dairies, which could potentially contribute to ozone formation. Because the impact of different VOCs on ozone formation varies significantly from one molecular species to another, detailed characterization of VOC emissions is essential to include all the important contributors to atmospheric chemistry and especially atmospheric reactivity. The present research study identifies and quantifies the VOCs emitted from various silages and other feedstuffs. Experiments were conducted in an environmental chamber under controlled conditions. Almost 80 VOCs were identified and quantified from corn (Zea mays L.), alfalfa (Medicago sativa L.),and cereal (wheat [Triticum aestivum L.] and oat [Avena sativava L.] grains) silages, total mixed ration (TMR), almond (Amygdalus communis L.) shells and hulls using gas chromatography-mass spectrometry and high performance liquid chromatography. The results revealed high concentrations of emitted alcohols and other oxygenated species. Lower concentrations of highly reactive alkenes and aldehydes were also detected. Additional quantitation and monitoring of these emissions are essential for assessment of and response to the specific needs of the regional air quality in the SJV. PMID:21488490