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Electrophoretic Methods (electrophoretic + methods)
Selected AbstractsElectrophoretic methods in pharmaceutical analysisELECTROPHORESIS, Issue 12 2006Hermann Wätzig No abstracts. [source] The role of electrophoresis in disease biomarker discoveryELECTROPHORESIS, Issue 12 2007Haleem J. Issaq Dr. Abstract There has been increased activity in the last few years in the search for disease markers using fractionation of complex biological fluids combined with MS. While electrophoretic and chromatographic separations have played a major role in this endeavor, this manuscript is limited to a review of electrophoretic methods that have been established for disease biomarker discovery. These methods include 2-DE, difference gel electrophoresis (DIGE), and CE. We define what constitutes a biomarker, identify the steps required for establishing a biomarker, and describe the parameters needed in the design of an ideal diagnostic test. The application, advantages, and limitations of CE, DIGE, and 2-DE in meeting the goal of discovering novel biomarkers is discussed in detail, along with a few selected examples that illustrate the search for biomarkers for cancer and neurological diseases. [source] Dual injection capillary electrophoresis: Foundations and applicationsELECTROPHORESIS, Issue 23-24 2004Feliciano Priego-Capote Abstract The state of the art of capillary electrophoresis (CE) approaches based on dual injection is here reported. Dual injection strategies have been proposed with three main objectives: (i) to provide information about reaction kinetics and/or related parameters, (ii) to perform in-capillary derivatization for improving separation and/or determination, (iii) to develop electrophoretic methods for the simultaneous analysis of anionic and cationic compounds. For the first two purposes, dual injection, which involves sample and reagent, can be realized either from the same end of the capillary (electrophoretically mediated microanalysis, EMMA) or from the two ends of the capillary (electroinjection analysis, EIA). The third objective, with dual injection of sample from the two ends of the capillary, takes advantage of moving cationic and anionic compounds with opposite directions. The foundations of each alternative, conditions necessary for working with them, restrictions, applications as well as perspectives are reviewed in order to establish the advantages, shortcomings, and convenience or no of their use in comparison to conventional CE. [source] Angiopoietin-2 in experimental colitisINFLAMMATORY BOWEL DISEASES, Issue 6 2010Vijay C. Ganta PhD Abstract Background: The pathophysiology of inflammatory bowel disease (IBD) includes leukocyte infiltration, blood and lymphatic remodeling, weight loss and protein enteropathy. The roles of angiopoietin-2 (Ang-2) in initiating gut inflammation, leukocyte infiltration and angiogenesis are not well understood. Methods: Disease activity index, histopathological scoring, myeloperoxidase assay, immunohistochemistry and sodium dodecyl sulphate- polyacrylamide gel electrophoretic methods were employed in the present study to addess the roles of Ang-2 in experimental colitis. Results: Several important differences were seen in the development of experimental IBD in Ang-2,/, mice. Although weight change and disease activity differ only slightly in WT and Ang-2,/, + DSS treated mice, leukocyte infiltration, inflammation and blood and lymphatic vessel density is significantly attenuated compared to WT + DSS mice. Gut capillary fragility and water export (stool blood and form) appear significantly earlier in Ang-2,/, + DSS mice vs. WT. Colon lengths were also significantly reduced in Ang-2,/, and gut histopathology was less severe in Ang-2,/, compared to WT + DSS. Lastly, the decrease in serum protein content in WT + DSS was less severe in Ang-2,/, + DSS, thus protein losing enteropathy (PLE) a feature of IBD is relieved by Ang-2,/,. Conclusion: These data demonstrate that in DSS colitis, Ang-2 mediates inflammatory hemangiogenesis, lymphangiogenesis and neutrophil infiltration to reduce some, but not all clinical features of IBD. The implications for Ang-2 manipulation in the development of IBD and other inflammatory diseases and treatments involving Ang-2 are discussed. (Inflamm Bowel Dis 2009) [source] Characterization of blond and Star Ruby (red) Jaffa grapefruits using antioxidant and electrophoretic methodsINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 3 2006Shela Gorinstein Summary Antioxidant and electrophoretic methods were used to characterize the quality differences between blond and Star Ruby (red) grapefruits. Dietary fibre, minerals and trace elements, total polyphenols, anthocyanins, flavonoids, phenolic and ascorbic acids were also determined. The antioxidant potential of red grapefruit was significantly higher than that of the blond fruit (P < 0.05) and correlated well with the total polyphenols (R2 from 0.8456 to 0.9711). In both the cultivars studied, thirty-two electrophoretic bands were detected [sodium dodecyl-polyacrylamide gel eletrophoresis (SDS-PAGE)]. The main electrophoretic bands occurred between 20 and 43 kDa in both grapefruits with few minor differences between the varieties. Our findings indicate the following (i) red grapefruit is preferable: it has a higher concentration of bioactive compounds and antioxidant potential than the blond; (ii) 1, 1-diphenyl-2-picrylhydrazyl (DPPH) test is a more sensitive method for the determination of antioxidant potential; (iii) there are some minor differences in electrophoretic patterns; (iv) antioxidant and electrophoretic methods are a good combination for characterization of differences of the same citrus fruits. [source] Gas phase isomeric differentiation of oleanolic and ursolic acids associated with heptakis-(2,6-di- O -methyl)-,-cyclodextrin by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometryJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 4 2010Zhan Yu Abstract Oleanolic acid (OA) and ursolic acid (UA) are isomeric triterpenoid compounds with similar pharmaceutical properties. Usually, modern chromatographic and electrophoretic methods are widely utilized to differentiate these two compounds. Compared with mass spectrometric (MS) methods, these modern separation methods are both time- and sample-consuming. Herein, we present a new method for structural differentiation of OA and UA by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) with the association of heptakis-(2,6-di- O -methyl)-,-cyclodextrin (DM-,-CD). Exact MS and tandem MS (MS/MS) data showed that there is no perceptible difference between OA and UA, as well as their ,-cyclodextrin and ,-cyclodextrin complexes. However, there is a remarkable difference in MS/MS spectra of DM-,-CD complexes of OA and UA. The peak corresponding to the neutral loss of a formic acid and a water molecule could only be observed in the MS/MS spectrum of the complex of DM-,-CD : OA. Molecular modeling calculations were also employed to further investigate the structural differences of DM-,-CD : OA and DM-,-CD : UA complexes. Therefore, by employing DM-,-CD as a reference reagent, OA and UA could be differentiated with purely MS method. Copyright © 2010 John Wiley & Sons, Ltd. [source] Effects of Xenobiotic Compounds on Cell Activities in Euplotes crassusTHE JOURNAL OF EUKARYOTIC MICROBIOLOGY, Issue 2 2005FRANCESCA TRIELLI It is now widely accepted that Protists are relevant bioassays to be exploited for the study of environmental modifications due to the presence of xenobiotic compounds. In this work, we evaluated the possibility of utilizing Euplotes crassus, an interstitial marine ciliate, for the pre-chemical screening of environmental sites, such as estuarine and coastal sediments. With this aim, we tested the sensitivity of E. crassus to exposure to three classes of pollutants: an organophosphate neurotoxic drug, basudin, largely used for pest control in agricultural sites, a toxic heavy metal, mercury (HgCl2), and an aromatic polycyclic hydrocarbon, benzopyrene (BP). We found a dose-dependent effect of these compounds on cell viability at concentrations ranging from 1/102 v/v to 1/107 v/v for basudin, from 5 ,M to 0.1 ,M for HgCl2, and from 50 ,M to 1 ,M for BP. In particular, 100% mortality was caused by a 1-h exposure to 1/105 v/v basudin, or 2 ,M HgCl2, or 25 ,M BP, and by a 24-h exposure to 1/106 v/v basudin, 0.5 ,M HgCl2, or 5 ,M BP. A significant decrease in the daily mean fission rate (P<0.001) was found after exposure to 1/107 v/v basudin, or 0.25 ,M HgCl2, or 1 ,M BP. Moreover, as it is well known that the inhibition of acetylcholinesterase (AChE) activity represents a specific biomarker for neurotoxic drugs, we first detected this enzyme activity in E. crassus, using cytochemical, spectrophotometric, and electrophoretic methods; then, AChE activity was characterized by its sensitivity to specific AChE inhibitors and to variations in pH and temperature. Like AChE present in higher organisms, the AChE activity detected in E. crassus was inhibited by exposure to basudin. Conversely, exposure to HgCl2, or PB did not inhibit AChE activity, but caused a significant reduction in lysosomal membrane stability. [source] Glutathione S-transferases in the adaptation to plant secondary metabolites in the Myzus persicae aphidARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY (ELECTRONIC), Issue 3 2005Frédéric Francis Abstract Glutathione S-transferases (GST) in insects play an important role in the detoxification of many substances including allelochemicals from plants. Induction of GST activity in Myzus persicae in response to secondary metabolites from Brassica plants was determined using different host plant species and confirmed using artificial diet with pure allelochemicals added. The 2,4-dinitro-1-iodobenzene (DNIB) was found to be a useful substrate for identifying particular GSTs in insects. GSTs from M. persicae were purified using different affinity chromatography columns and related kinetic parameters were calculated. GST isoenzymes were characterised using electrophoretic methods. Although SDS-PAGE results indicated similarity among the purified enzymes from each affinity column, biochemical studies indicated significant differences in kinetic parameters. Finally, the GST pattern of M. persicae was discussed in terms of insect adaptation to the presence of plant secondary substances such as the glucosinolates and the isothiocyanates, from Brassicaceae host plants. Arch. Insect Biochem. Physiol. 58:166,174, 2005. © 2005 Wiley-Liss, Inc. [source] Review modeling the free solution and gel electrophoresis of biopolymers: The bead array-effective medium modelBIOPOLYMERS, Issue 2-3 2007Stuart A. Allison Abstract Free solution and gel electrophoresis is an extremely useful tool in the separation of biopolymers. The complex nature of biopolymers, coupled with the usefulness of electrophoretic methods, has stimulated the development of theoretical modeling over the last 30 years. In this work, these developments are first reviewed with emphasis on Boundary Element and bead methodologies that enable the investigator to design realistic models of biopolymers. In the present work, the bead methodology is generalized to include the presence of a gel through the Effective Medium model. The biopolymer is represented as a bead array. A peptide, for example, made up of N amino acids is modeled as 2N beads. Duplex DNA is modeled as a discrete wormlike chain consisting of touching beads. The technical details of the method are placed in three Appendices. To illustrate the accuracy and effectiveness of the approach, two applications are considered. Model studies on both the free solution mobility of 73 peptides ranging in size from 2 to 42 amino acids, and the mobility of short duplex DNA in dilute agarose gels are discussed. © 2007 Wiley Periodicals, Inc. Biopolymers 87: 102,114, 2007. This article was originally published online as an accepted preprint. The "Published Online" date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com [source] | |||||||||||||