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Full-Text Articles in Physical Sciences and Mathematics
Quantitative Structure-Activity Relationships For Polychlorinated Hydroxybiphenyl Estrogen Receptor Binding Affinity: An Assessment Of Conformer Flexibility, Steven P. Bradbury, Ovanes G. Mekenyan, Gerald T. Ankley
Quantitative Structure-Activity Relationships For Polychlorinated Hydroxybiphenyl Estrogen Receptor Binding Affinity: An Assessment Of Conformer Flexibility, Steven P. Bradbury, Ovanes G. Mekenyan, Gerald T. Ankley
Steven P. Bradbury
A diverse group of xenobiotics has a high binding affinity to the estrogen receptor (ER), suggesting that it can accommodate large variability in ligand structure. Relationships between xenobiotic structure, binding affinity, and estrogenic response have been suggested to be dependent on the conformational structures of the ligands. To explore the influence of conformational flexibility on ER binding affinity, a quantitative structure—activity relationship (QSAR) study was undertaken with estradiol, diethylstilbestrol, and a set of polychlorinated hydroxybiphenyls (PCHBs) of environmental concern. Although the low-energy minima of the PCHB congeners suggested that interconversions among conformers were likely, the electronic parameters associated with the …
Estimating One-Electron Reduction Potentials Of Quinones, Steven P. Bradbury, Ovanes G. Mekenyan, V. B. Kamenska
Estimating One-Electron Reduction Potentials Of Quinones, Steven P. Bradbury, Ovanes G. Mekenyan, V. B. Kamenska
Steven P. Bradbury
The one-electron reduction potential ∗ E1 7 of benzo-, naphtho-and anthracenequinones is related to their ability to undergo redox cycling and elicit cytotoxicity through oxidative stress. To evaluate a general approach to estimate the E1 7 of benzo-, naphtho-and anthracenequinones, QSAR approaches based on gas phase and solvation based methods were employed. Stereoelectronic descriptors of ground state quinones, respective intermediates of the redox cycle, and the di erences in parameters for the transition between intermediates were evaluated. The variation of E1 7 was correlated with descriptors of the parent quinones and speci c transition parameters. The energy of the highest …
2,3, 7,8-Tetrachlorodibenzo-P-Dioxin, Steven P. Bradbury
2,3, 7,8-Tetrachlorodibenzo-P-Dioxin, Steven P. Bradbury
Steven P. Bradbury
Since 1985, the United States Environmental Protection Agency (USEPA) has classified 2,3,7,8-tetrachloro-p-dioxin (TCDD) as a probable human carcinogen; subsequently, sources of TCDD in the environment have been regulated on the basis of animal cancer rates extrapolated to doses associated with human exposures. Two major activities have prompted the decision to reassess this approach for evaluating TCDD toxicity and its associated risks. First, an epidemiological study of cancer mortality in U.S. chemical workers by the National Institute of Occupational Safety and Health provided evidence of TCDD-mediated human carcinogenicity (Fingerhut et al. 1991 ). Second, at a 1990 Banbury conference a consensus …