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Index Analyses (index + analysis)
Selected AbstractsA 3-D QSAR Study of Catechol- O -Methyltransferase Inhibitors Using CoMFA and CoMSIAMOLECULAR INFORMATICS, Issue 10 2008Chunzhi Ai Abstract Inhibitors of Catechol- O -Methyltransferase (COMT) play an important role in the treatment of Parkinson's Disease (PD). A new Three-Dimensional Quantitative Structure,Activity Relationship (3-D QSAR) analysis was performed on 36 previously reported COMT inhibitors employing Comparative Molecular Field Analysis (CoMFA) and Comparative Molecular Similarity Indices Analysis (CoMSIA) methodologies to correlate the molecular fields and percent inhibition values and three predictive models were derived. The CoMFA and CoMSIA models with steric and electrostatic field yielded cross-validated rs of 0.585 and 0.528, respectively whereas the conventional rs were 0.979 and 0.891, respectively. The CoMSIA model with hydrophobic field exhibited a r of 0.544 and a r of 0.930. The individual inspection of 3-D contours generated from these models helps in understanding the possible region for structural modification of molecules to improve the inhibitory bioactivity. These 3-D QSAR models are also useful for designing and predicting novel COMT inhibitors. [source] A chromametric method for the rapid assessment of deep frying oil qualityJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 13 2003Xin-Qing Xu Abstract A rapid chromametric method was developed for the assessment of deep frying oil quality based on the strong correlation between colour index and total polar compounds in deep frying oil. Colour indices of frying oil samples, measured by chromameter, decreased significantly during frying and were strongly correlated with frying time (r , 0.95, p < 0.001). Colour indices of a set of oil samples taken from 0 to 80 h of deep frying were also significantly correlated with total polar compounds of the same samples determined using the official method of the American Oil Chemists' Society (r = 0.96, p < 0.001). The equation for conversion of the colour index (x) to the content of total polar compounds (y) in an oil sample is y = 0.0174x2 , 2.9506x + 124.34. In addition, colour indices of 10 different types of frying oils were strongly correlated with the corresponding contents of total polar compounds in the oils with samples taken from 0 to 80 h of deep frying in duplicate (r = 0.95, p < 0.001, n = 220). The results of colour index analyses agreed well with the results of chemical and sensory analyses of the frying oils tested. This chromametric method is rapid, convenient and reliable. Copyright © 2003 Society of Chemical Industry [source] Synergistic interaction between trifluorothymidine and docetaxel is sequence dependentCANCER SCIENCE, Issue 11 2008I.V. Bijnsdorp Docetaxel is a microtubule inhibitor that has actions in the S and G2,M phase of the cell cycle. The pyrimidine trifluorothymidine (TFT) induces DNA damage and an arrest in the G2,M phase. TFT, as part of TAS-102, has been clinically evaluated as an oral chemotherapeutic agent in colon and gastric cancer. The aim of the present study was to determine the optimal administration sequence of TFT and docetaxel and to investigate the underlying mechanism of cytotoxicity. Drug interactions were examined by sulforhodamine B assays and subsequent combination index analyses, and for long-term effects the clonogenic assay was used. A preincubation with docetaxel was synergistic in sulforhodamine B (combination index 0.6,0.8) and clonogenic assays, and was accompanied by a time-dependent cell death induction (17,36%), the occurrence of polynucleation (22%), and mitotic spindle inhibition as determined by flow cytometry and immunostaining. Interestingly, administration of TFT followed by the combination displayed strong antagonistic activity, and was accompanied by less polynucleation and cell death induction than the synergistic combinations. Western blotting showed that the G2,M-phase arrest (25,50%) was accompanied by phosphorylation of Chk2 and dephosphorylation of cdc25c in the synergistic combinations. Together, this indicates that synergistic activity requires docetaxel to initiate mitotic failure prior to the activation of TFT damage signaling, whereas antagonism is a result of TFT cell cycle-arrested cells being less susceptible to docetaxel. Caspase 3 activation was low after docetaxel, suggestive of caspase-independent mechanisms of cell death. Taken together, our models indicate that combination treatment with docetaxel and TFT displays strong synergy when docetaxel is given first, thus providing clues for possible clinical studies. (Cancer Sci 2008; 99: 2302,2308) [source] Stellar populations of seven early-type dwarf galaxies and their nuclei,ASTRONOMISCHE NACHRICHTEN, Issue 9-10 2009S. Paudel Abstract Dwarf galaxies are the numerically dominating population in the dense regions of the universe. Although they seem to be simple systems at first view, the stellar populations of dwarf elliptical galaxies (dEs) might be fairly complex. Nucleated dEs are of particular interest, since a number of objects exhibit different stellar populations in their nuclei and host galaxy. We present stellar population parameters obtained from integrated optical spectra using a Lick index analysis of seven nucleated dwarf elliptical galaxies and their nuclei. After subtracting the scaled galaxy spectra from the nucleus spectra, we compared them with one another and explore their stellar populations. As a preliminary result, we find that the luminosity weighted ages of the nuclei slightly lower than those of galaxies, however, we do not see any significant difference in metallicity of the host galaxies and their nuclei (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] A combined molecular modeling study on gelatinases and their potent inhibitorsJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 1 2010Lili Xi Abstract Zinc-dependent matrix metalloproteinase (MMP) family is considered to be an attractive target because of its important role in many physiological and pathological processes. In the present work, a molecular modeling study combining protein-, ligand- and complex-based computational methods was performed to analyze a new series of ,- N -biaryl ether sulfonamide hydroxamates as potent inhibitors of gelatinase A (MMP-2) and gelatinase B (MMP-9). Firstly, the similarities and differences between the binding sites of MMP-2 and MMP-9 were analyzed through sequence alignment and structural superimposition. Secondly, in order to extract structural features influencing the activities of these inhibitors, quantitative structure-activity relationship (QSAR) models using genetic algorithm-multiple linear regression (GA-MLR), comparative molecular field (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) were developed. The proposed QSAR models could give good predictive ability for the studied inhibitors. Thirdly, docking study was employed to further explore the binding mode between the ligand and protein. The results from all the above analyses could provide the information about the similarities and differences of the binding mode between the MMP-2, MMP-9 and their potent inhibitors. The obtained results can provide very useful information for the design of new potential inhibitors. © 2009 Wiley Periodicals, Inc. J Comput Chem 2010 [source] 3D-QSAR Studies on C24-Monoalkylated Vitamin D3 26,23-Lactones and their C2, -Modified Derivatives with Inhibitory Activity to Vitamin D ReceptorMOLECULAR INFORMATICS, Issue 8-9 2010Jinhu Wang Abstract The ligand-based three-dimensional quantitative structure-activity relationship (3D-QSAR) for 82 inhibitors of 25-dehydro-1, -hydroxyvitamin D3 -26,23-lactone analogs has been studied by using comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) models. The established CoMFA model in training set gives a cross-validated q2 value of 0.516 and a non-cross-validated rncv2 value of 0.667, while the CoMSIA model results in q2=0.517 and rncv2=0.632. In general, the predictive ability of the CoMFA model is superior to that of the CoMSIA model, with rpred2=0.639 for the CoMFA and rpred2=0.619 for the CoMSIA model. Based on the CoMFA contour maps, some key structural characters of vitamin D3 analogs responsible for inhibitory activity are identified, and some new C2, -modified 24-alkylvitamin D3 lactone analogs with high predicted pIC50 values are designed. The ligand functional group mutations by FEP simulation and docking studies reveal the rationality of the molecular design. [source] |