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" Cytotoxic and genotoxic activity of benzo(a);pyrene adsorbed on particles in a model system "
N. M. Atkins, Jr.
J. T. Zelikoff
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Latin Dissertation
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English
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| Record Number
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1112701
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| Doc. No
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TLpq303908828
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| Main Entry
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J. T. Zelikoff
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N. M. Atkins, Jr.
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| Title & Author
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Cytotoxic and genotoxic activity of benzo(a);pyrene adsorbed on particles in a model system\ N. M. Atkins, Jr.J. T. Zelikoff
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| College
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New York University
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| Date
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1990
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| student score
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1990
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| Degree
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Ph.D.
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| Page No
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168
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| Abstract
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Benzo (a) pyrene (B (a) P), a combustion by-product and ubiquitous toxic contaminant, is adsorbed on airborne particles. Because differences in the physicochemical properties of adsorbent particles may be important in the biologic activity of this known carcinogen, B (a) P was studied in a model particle system. B (a) P was sorbed in varying concentrations on well-characterized charcoal, cola fly ash (CFA), and titanium dioxide (TiO2) particles. Metabolically competent Syrian hamster embryo (SHE) cells and non-metabolically active Chinese hamster V79 cells were exposed to the chemical adsorbate, the particle substrate and the whole particulate matter complex. The genotoxicities from 24 h exposures were compared using mutation and Sister chromatid exchange (SCE) endpoints, while the cytotoxicities from 6-day exposures were evaluated by reductions in clonal survival. Particle adsorption of B (a) P decreased SCE induction ins SHE cells, most significantly for charcoal (p < 0.05), compared to SCE induction by equivalent doses of B (a) P in solution. Nonetheless, at the highest B (a) P surface concentration, SCE frequency was significantly greater than that from the particle control. Proportionately less B (a) P was effectively available to the cells when adsorbed on particles than when in soluble form: CFA-adsorbed B (a) P was 32 percent available, while charcoal-adsorbed B (a) P was only 0.04-1.0 percent available, using SCE as the endpoint. In addition, adsorbate bioavailability varied directly as a function of increasing particle surface loading. The order of cytotoxicities was wood charcoal > TiO2 > CFA. The cytotoxicity of TiO2 with adsorbed B (a) P was significantly greater than that expected from simple addition of the individual cytotoxicities of the particle and the adsorbate. These results indicate that differences in particle surface properties can selective inhibit cellular availability of adsorbates as a function of particle chemistry (particularly carbon content) and physical morphology. Moreover, these differences should be considered explicitly in risk assessment studies of particles and their adsorbates. Given sufficiently high surface loadings, however, significant genotoxic damage can occur even from adsorbent particles highly effective in decreasing B (a) P availability. Results also support the concept that particle-adsorbate interactions can transform B (a) P into metabolically more active products as a function of the chemical properties of the particle substrate.
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air pollution
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benzo(a)pyrene
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cytotoxic activity
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Environmental science
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Health and environmental sciences
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particle adsorption
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