@article {2388, title = {Potential new inorganic antitumour agents from combining the anticancer traditional Chinese medicine (TCM) liriodenine with metal ions, and DNA binding studies}, journal = {Dalton Transactions}, number = {2}, year = {2009}, note = {ISI Document Delivery No.: 385IHTimes Cited: 6Cited Reference Count: 68Chen, Zhen-Feng Liu, Yan-Cheng Liu, Li-Min Wang, Heng-Shan Qin, San-Hai Wang, Bo-Long Bian, He-Dong Yang, Bin Fun, Hoong-Kun Liu, Hua-Gang Liang, Hong Orvig, Chris}, pages = {262-272}, type = {Article}, abstract = {Liriodenine (L), an active component of the anticancer traditional Chinese medicine (TCM), was isolated from Zanthoxylum nitidum. Its reactions with Pt(II) and Ru(II) afforded three metal complexes: cis-[PtCl2(L)] (1), cis-[PtCl2(L)(DMSO)] (2), and cis-[RuCl2(L)(DMSO)(2)]center dot 1.5H(2)O (3), the crystal structures of L, 2 and 3 were determined by single-crystal X-ray diffraction methods. These complexes were fully characterized by elemental analysis, IR spectrophotometry, H-1 and C-13 NMR spectroscopies, and ES mass spectrometry. The in vitro cytotoxicity of L and complexes 1-3 against 11 human tumour cell lines was assayed. The metal-based compounds exhibit enhanced cytotoxicity vs. free L, suggesting that these compounds display synergy in the combination of metal ions and liriodenine. The binding properties of L and its complexes 1-3 to ct-DNA were investigated through UV-vis, fluorescence, CD spectra, viscosity and agarose gels electrophoretic measurements.}, keywords = {AFFINITY, ALKALOIDS, CISPLATIN, CYTOTOXIC ACTIVITY, DRUGS, FLUORESCENCE, IN-VITRO, PLATINUM(II) COMPLEXES, RUTHENIUM(II) COMPLEXES, TOPOISOMERASE-II}, isbn = {1477-9226}, url = {://000261807400006}, author = {Chen, Z. F. and Liu, Y. C. and Liu, L. M. and Wang, H. S. and Qin, S. H. and Wang, B. L. and Bian, H. D. and Yang, B. and Fun, H. K. and Liu, H. G. and Liang, H. and Orvig, Chris} } @article {4301, title = {Calcium binding by the N-terminal cellulose-binding domain from Cellulomonas fimi beta-1,4-glucanase CenC}, journal = {Biochemistry}, volume = {37}, number = {37}, year = {1998}, note = {ISI Document Delivery No.: 125NRTimes Cited: 16Cited Reference Count: 33}, month = {Sep}, pages = {12772-12781}, type = {Article}, abstract = {The interaction of the N-terminal cellulose-binding domain, CBDN1, from Cellulomonas fimi beta-1,4-glucanase CenC with calcium was investigated using NMR spectroscopy and calorimetry. CBDN1 binds a single calcium ion with an equilibrium association constant of approximately 10(5) M-1 at 35 degrees C and pH 6.0. Binding is exothermic (-42 +/- 2 kJ mol(-1)) under these conditions and is accompanied by a small negative change in heat capacity (Delta C-p = -0.41 +/- 0.16 kJ mol(-1) K-1). From an NMR line shape analysis, the rate constants for calcium association and dissociation were found to be (5 +/- 7) x 10(7) s(-1) M-1 and (4.5 +/- 0.6) x 10(2) s(-1), respectively. The rapid association kinetics indicate that the calcium-binding site on CBDN1 is accessible and, to the first approximation, preformed. Based on patterns of chemical shift perturbations, and structural comparisons with the Bacillus sp. 1,3-1,4-beta-glucanases, the backbone carbonyl oxygens of Thr8, Gly30, and Asp 142 and a side chain carboxyl oxygen of Asp 142 are postulated to form the calcium-binding site of CBDN1. Consistent with the calcium-independent affinity of CBDN1 for cellopentaose, this exposed site is located on the face of CBDN1 opposite to that forming the oligosaccharide-binding cleft. The midpoint denaturation temperature of CBDN1 is increased by approximately 8 degrees C at pH 6.0 in the presence of saturating amounts of calcium, confirming that metal ion binding is thermodynamically linked to native-state stability.}, keywords = {4-GLUCANOHYDROLASE, AFFINITY, CA2+, CRYSTAL-STRUCTURE, GLUCANASES, NUCLEAR-MAGNETIC-RESONANCE, RESOLUTION, SPECTROSCOPY, THERMODYNAMICS, THERMOSTABILITY}, isbn = {0006-2960}, url = {://000076244100011}, author = {Johnson, P. E. and Creagh, A. L. and Brun, E. and Joe, K. and Tomme, P. and Haynes, C. A. and McIntosh, L. P.} } @article {4207, title = {Dynamic complexation of solutes in capillary electrophoresis}, journal = {Electrophoresis}, volume = {19}, number = {3}, year = {1998}, note = {ISI Document Delivery No.: ZD713Times Cited: 12Cited Reference Count: 28}, month = {Mar}, pages = {383-387}, type = {Article}, abstract = {The analyte migration behavior in any chemical separation system can be described using a single equation that unifies all areas of separation science. This equation can be used in capillary electrophoresis (CE) to design separation systems, and to study interactions between analytes and additives. By using individual capacity factors for each analyte species present in the system, and with the knowledge of the characteristics of each interaction, one can predict the analyte migration behavior in complicated CE systems, including systems with multiple 1:1 interactions and/or higher order interactions.}, keywords = {AFFINITY, BETA-CYCLODEXTRIN, BINDING, capacity factor, CHIRAL SEPARATIONS, dynamic complexation capillary electrophoresis, ENANTIOMERS, higher order interactions, MICELLAR ELECTROKINETIC CHROMATOGRAPHY, multiple equilibria, OPTIMIZATION, RESOLUTION, SELECTIVITY, separation theory, TIOCONAZOLE, ZONE ELECTROPHORESIS}, isbn = {0173-0835}, url = {://000072716000003}, author = {Bowser, M. T. and Chen, D. D. Y.} } @article {4205, title = {Higher order equilibria and their effect on analyte migration behavior in capillary electrophoresis}, journal = {Analytical Chemistry}, volume = {70}, number = {15}, year = {1998}, note = {ISI Document Delivery No.: 107VQTimes Cited: 38Cited Reference Count: 31}, month = {Aug}, pages = {3261-3270}, type = {Article}, abstract = {This paper presents a quantitative investigation into the effect of analyte-additive interactions on analyte migration behavior in capillary electrophoresis (CE) when both 1:1 and 1:2 stoichiometries are present. Equations based on the individual capacity factors for each interaction are derived to account for the effect of both first- and second-order equilibria. The analyte migration behavior is described using these equations with a full account of how the microscopic equilibrium constants and microscopic mobilities are combined to give the macroscopic values. The binding isotherms of interactions with both 1:1 and 1:2 stoichiometries are compared with those of a 1:1 stoichiometry. 4,4{\textquoteright}-Biphenol and 4-phenylphenol were chosen as analytes that undergo complexation with one and two hydroxypropyl-beta-cyclodextrin (HP-beta-CD) molecules; phenol was used as an analyte that interacts with only one HP-beta-CD molecule. The process of calculating higher order equilibrium constants and complex mobilities from the binding isotherms is demonstrated. The effects of experimental conditions, such as the additive concentration range and the number of data points, on the error in the calculated constants and the ability of the equations to accurately describe the experimental data are discussed. A comparison of the linear transformations of the binding isotherm with respect to their ability to detect higher order equilibria is made, and the advantage of using the capacity factor in CE is illustrated.}, keywords = {AFFINITY, BETA-CYCLODEXTRIN, BINDING, CHIRAL SEPARATION, METAL-IONS, SELECTIVITY, SELECTORS, THEORETICAL ASPECTS, TIOCONAZOLE ENANTIOMERS, ZONE ELECTROPHORESIS}, isbn = {0003-2700}, url = {://000075232000034}, author = {Bowser, M. T. and Chen, D. D. Y.} } @article {4306, title = {Indirect enzyme-linked immunosorbent assay for the quantitative estimation of lysergic acid diethylamide in urine}, journal = {Clinical Chemistry}, volume = {44}, number = {5}, year = {1998}, note = {ISI Document Delivery No.: ZL795Times Cited: 5Cited Reference Count: 27}, month = {May}, pages = {985-990}, type = {Article}, abstract = {A new antibody to lysergic acid diethylamide (LSD) was used to develop a novel indirect ELISA for the quantification of drug in urine. Evaluation of the new assay with the commercially available LSD ELISA (STC Diagnostics) shows improved performance. The test requires 50 mu L of urine, which is used to measure concentrations of drug in the mu g/L to ng/L range. The Limit of detection was 8 ng/L compared with 85 ng/L in the commercial assay, and analytical recoveries were 98-106\%. Our test detected 0.1 mu g/L of LSD in urine with an intraassay CV of 2.4\% (n = 8) compared with 6.0\% for a 0.5 mu g/L sample in the commercial assay (n = 20). The upper and lower limits of quantification were estimated to be 7 mu g/L and 50 ng/L, respectively. Specificity was evaluated by measuring the extent of cross-reactivity with 24 related substances. Drug determination using the new assay offers both improved sensitivity and precision compared with existing methods, thus facilitating the preliminary quantitative estimation of LSD in urine at lower concentrations with a greater degree of certainty.}, keywords = {AFFINITY, BODY-FLUIDS, ELISA, GAS-CHROMATOGRAPHY, METABOLITES, MONOCLONAL-ANTIBODIES, N-DEMETHYL-LSD, RADIOIMMUNOASSAY, SERUM, TANDEM MASS-SPECTROMETRY}, isbn = {0009-9147}, url = {://000073472300014}, author = {Kerrigan, S. and Brooks, D. E.} } @article {4209, title = {Properties of multivariate binding isotherms in capillary electrophoresis}, journal = {Analytical Chemistry}, volume = {70}, number = {6}, year = {1998}, note = {ISI Document Delivery No.: ZC318Times Cited: 16Cited Reference Count: 30}, month = {Mar}, pages = {1076-1084}, type = {Article}, abstract = {When more than one complexation additive is used in capillary electrophoresis (CE), the migration behavior of an analyte can be described using contour plots and profile plots of the multivariate binding isotherms, At a certain concentration of one additive, the net electrophoretic mobility of the analyte is not affected by the concentration of the second additive, even though the second additive does alter the mobility of the analyte when used alone. The concentration of the first additive, in this situation, is defined as the dengsu concentration (dengsu means "same speed" in Chinese), The presence of a dengsu concentration for one additive is a strong indication that the second additive interacts with the analyte in a 1:1 (analyte-additive) stoichiometry, The binding isotherms in a profile plot can be used to unambiguously determine the binding stoichiometry of the analytes, as well as to determine the effect of interactions between the additives. The apparent complex mobilities obtained from the profile plots can also be used to determine whether there are interactions between the additives or whether the analyte can bind both additives at the same time.}, keywords = {AFFINITY, BETA-CYCLODEXTRIN, CHIRAL SEPARATION, POLYETHERS, RESOLUTION, SELECTIVITY, THEORETICAL ASPECTS, TIOCONAZOLE ENANTIOMERS}, isbn = {0003-2700}, url = {://000072565200004}, author = {Bowser, M. T. and Kranack, A. R. and Chen, D. D. Y.} } @article {3911, title = {Prediction of the migration behavior of analytes in capillary electrophoresis based on three fundamental parameters}, journal = {Journal of Chromatography A}, volume = {781}, number = {1-2}, year = {1997}, note = {ISI Document Delivery No.: YC198Times Cited: 11Cited Reference Count: 309th International Symposium on High Performance Capillary Electrophoresis and Related Microscale TechniquesJAN 26-30, 1997ORLANDO, FL}, month = {Sep}, pages = {23-34}, type = {Proceedings Paper}, abstract = {The prediction of analyte migration behavior in capillary electrophoresis (CE) is essential for rapid method development. The dynamic complexation model, based on 1:1 interactions, was used to accurately predict the apparent electrophoretic mobilities and the migration times of a group of deoxyribonucleotides (dNPs) at various concentrations of beta-cyclodextrin (beta-CD). The electrophoretic mobility of the analyte, the electrophoretic mobility of the analyte-additive complex and the equilibrium constant are the three fundamental parameters required to determine the mobility of an analyte. The apparent migration time of the analyte can be predicted once the electroosmotic mobility and relative viscosity of the solution are known. Optimum separation conditions can be determined based on these parameters. Excellent agreement between observed analyte migration behavior and predicted values was demonstrated, with relative errors being often less than 1\%. The theory was tested repeatedly under various conditions in order to assess its predictive capabilities and limitations. Analysis by molecular modelling, in conjunction with calculated electrophoretic parameters and equilibrium constants, provided deeper insight into the probable mechanisms of the separation process at the molecular level. (C) 1997 Elsevier Science B.V.}, keywords = {AFFINITY, BETA-CYCLODEXTRIN, BINDING, CHIRAL SEPARATION, CONSTANTS, deoxyribonucleotides, ELECTROKINETIC CHROMATOGRAPHY, ENANTIOMERS, migration behaviour, migration time prediction, MODEL, OPTIMIZATION, SELECTORS, TIOCONAZOLE}, isbn = {0021-9673}, url = {://A1997YC19800005}, author = {BritzMcKibbin, P. and Chen, D. D. Y.} } @article {3909, title = {Quantitative description of migration behavior of porphyrins based on the dynamic complexation model in a nonaqueous capillary electrophoresis system}, journal = {Electrophoresis}, volume = {18}, number = {1}, year = {1997}, note = {ISI Document Delivery No.: WH231Times Cited: 47Cited Reference Count: 48}, month = {Jan}, pages = {82-91}, type = {Article}, abstract = {The effect of an additive (Brij 35) on the mobilities of a group of porphyrin acids is quantitatively characterized based on a 1:I dynamic complexation model. Varying additive concentration shifts the equilibrium and changes the viscosity of the background electrolyte. The equilibrium constant, the electrophoretic mobility of the free analyte, and the electrophoretic mobility of the complex are identified as the parameters necessary to describe the analytes{\textquoteright} migration behavior. Several statistical methods for obtaining these parameters are discussed. The equilibrium constants and complex mobilities are calculated using three different linear regression methods. The weighted y-recip-rocal method was preferred because it gives smaller error, and the data points are evenly distributed along the concentration axis. These values are confirmed using a nonlinear regression to ensure that the proper weighting was used in the linear regression plots. The parameters are then used to predict the apparent mobilities of the analytes over the entire additive concentration range, allowing the optimum separation conditions to be identified. For disclike molecules, such as porphyrins, the mobility is determined by the orientation of the molecule in an electric field, in addition to their size and charge. The strength of binding between the porphyrins and Brij 35 depends on the number of binding sites and the solvation shell.}, keywords = {additives, AFFINITY, ANIONS, BETA-CYCLODEXTRIN, BINDING, CHIRAL SEPARATION, DYNAMIC COMPLEXATION, ENANTIOMERS, nonaqueous capillary electrophoresis, PARAMETERS, PORPHYRIN, SELECTIVITY, SELECTORS, separation theory, TIOCONAZOLE, ZONE ELECTROPHORESIS}, isbn = {0173-0835}, url = {://A1997WH23100016}, author = {Bowser, M. T. and Sternberg, E. D. and Chen, D. D. Y.} } @article {7360, title = {HYDROXYPROPYL CELLULOSE POLY(ETHYLENE GLYCOL)-CO-POLY(PROPYLENE GLYCOL) AQUEOUS 2-PHASE SYSTEMS - SYSTEM CHARACTERIZATION AND PARTITION OF CELLS AND PROTEINS}, journal = {Enzyme and Microbial Technology}, volume = {14}, number = {10}, year = {1992}, note = {ISI Document Delivery No.: JP468Times Cited: 16Cited Reference Count: 23}, month = {Oct}, pages = {785-790}, type = {Article}, abstract = {Novel aqueous polymeric two-phase systems are described. These systems are formed by mixing hydroxypropyl cellulose (molecular mass 100,000, trade name Klucel L) with poly(ethylene glycol)-co-poly(propylene glycol) copolymer [molecular mass 6,500, poly(propylene glycol) content 50\% w/w, trade name Pluronic P105], in a saline buffer. The phase diagram was measured and the interfacial tensions, phase separation times, and lower phase viscosities of three phase systems having constant Pluronic P105 concentration but varying in Klucel L concentration were determined. The partition behavior of a representative cell, bacterium, and protein and the affinity ligand-mediated alteration in the partition behavior of a protein from a yeast extract protein mixture were also characterized. The results suggest that Klucel L/Pluronic P105 phase systems may be cost-effective substitutes for, or complements to, existing aqueous polymeric phase systems. The physical characterization and representative partition data reported here should facilitate application of these new systems.}, keywords = {AFFINITY, AQUEOUS 2-PHASE SYSTEMS, BAKERS-YEAST, DEXTRAN, GLUCOSE-6-PHOSPHATE DEHYDROGENASE, GLYCOL)-CO-POLY(PROPYLENE GLYCOL) COPOLYMER, HUMAN ERYTHROCYTE, HYDROXYPROPYL CELLULOSE, PARTITION, POLY(ETHYLENE, polymer, PURIFICATION, SALMONELLA-ENTERIDITIS, TENSION}, isbn = {0141-0229}, url = {://A1992JP46800002}, author = {Skuse, D. R. and Norrisjones, R. and Yalpani, M. and Brooks, D. E.} }