bluuebunny/crossref_metadata_2025_split huggingface dataset:
Capillary electrophoresis analysis of fosfomycin in biological fluids for clinical pharmacokinetic studies
Authors: Petsch Martina , Mayer‐Helm Bernhard X. , Sauermann Robert , Joukhadar Christian , Kenndler Ernst 
Published: July 2004

AbstractA feasible capillary zone electrophoresis (CZE) method with indirect UV and contactless conductivity detection was developed for the determination of fosfomycin, an antibiotic, in human plasma and microdialysis samples. Samples were collected from test persons during a clinical trial. The background electrolytes used consisted of 25 mM benzoic acid and 0.5 mM hexadecyltrimethylammonium bromide, adjusted with tris(hydroxymethyl)aminomethane solution to pH 6.95 for plasma, and to pH 8.05 for microdialysis samples. CZE separations of the anionic analyte were carried out with reversed electroosmotic flow directed towards the anode. The limit of detection was between 0.6 and 2 μg/mL, depending on the matrix and the detection method. No sample preparation was needed for microdialysis samples; for plasma samples, proteins were precipitated with methanol (1+2, v+v), and the supernatant was analyzed. The yield determined with spiked samples was about 100%, the reproducibility of the entire method, expressed by the RSD% of three independent determinations of fosfomycin in triplicate after spiking Ringer's solutions and plasma samples, respectively, was better than 8%. The method is thus well‐suited for clinical studies for the determination of the antibiotic in biological fluids.
Capillary electrophoresis of biological particles: Viruses, bacteria, and eukaryotic cells
Authors: Kremser Leopold , Blaas Dieter , Kenndler Ernst 
Published: July 2004

AbstractA review about the application of electrophoretic methods in the capillary format for the investigation of large biological assemblies like viruses, bacteria, yeast or entire mammalian cells is given. These entities are of a size ranging between some nanometers and tens of micrometers. They can form colloidal solutions or dispersions and move under the influence of an electric field. They are separated by zone electrophoresis according to their different electrophoretic velocity, and characterized by the electrophoretic mobility, which is easily determinable in free solution in capillaries or in other microdevices. As the charge of these particles, when being amphoteric, is pH‐dependent, isoelectric focusing can also be carried out and the capillary format is increasingly being employed for their separation and determination of pI values. Furthermore, interactions with ligands can be assessed by various modes of affinity capillary electrophoresis. Capillary zone electrophoresis has thus become a valuable tool for investigation of large macromolecular assemblies in the field of biochemistry, clinical chemistry, toxicology, and nutrition chemistry amongst many others.
Integrated on‐chip derivatization and electrophoresis for the rapid analysis of biogenic amines
Authors: Beard Nigel P. , Edel Joshua B. , deMello Andrew J. 
Published: July 2004

AbstractWe demonstrate the monolithic integration of a chemical reactor with a capillary electrophoresis device for the rapid and sensitive analysis of biogenic amines. Fluorescein isothiocyanate (FITC) is widely employed for the analysis of amino‐group containing analytes. However, the slow reaction kinetics hinders the use of this dye for on‐chip labeling applications. Other alternatives are available such as o‐phthaldehyde (OPA), however, the inferior photophysical properties and the UV λmax present difficulties when using common excitation sources leading to a disparity in sensitivity. Consequently, we present for the first time the use of dichlorotriazine fluorescein (DTAF) as a superior in situ derivatizing agent for biogenic amines in microfluidic devices. The developed microdevice employs both hydrodynamic and electroosmotic flow, facilitating the creation of a polymeric microchip to perform both precolumn derivatization and electrophoretic analysis. The favorable photophysical properties of the DTAF and its fast reaction kinetics provide detection limits down to 1 nM and total analysis times (including on‐chip mixing and reaction) of <60 s. The detection limits are two orders of magnitude lower than current limits obtained with both FITC and OPA. The optimized microdevice is also employed to probe biogenic amines in real samples.
Capillary electrochromatography of peptides and proteins
Authors: Li Yan , Xiang Rong , Wilkins James A. , Horváth Csaba 
Published: July 2004

AbstractThis paper reviews recent progress in bioanalysis using capillary electrochromatography (CEC), especially in the field of separation of proteins and peptides. Fundamentals of CEC are briefly discussed. Since most of the recent developments on CEC have focused on column technology, i.e., design of new stationary phases and development of new column configurations, we describe here a variety of column architectures along with their advantages and disadvantages. Newly emerged column technologies in CEC for high speed and high efficiency separation are also discussed. Different analytical platforms of CEC such as pressure‐assisted CEC or voltage‐assisted micro‐ high‐performance liquid chromatography (HPLC), CEC with different detection techniques, CEC on microchip platforms and multidimensional electrochromatography with their applications in peptide and protein analysis are presented.
Which genetic marker for which conservation genetics issue?
Authors: Wan Qiu‐Hong , Wu Hua , Fujihara Tsutomu , Fang Sheng‐Guo 
Published: July 2004

AbstractConservation genetics focuses on the effects of contemporary genetic structuring on long‐term survival of a species. It helps wildlife managers protect biodiversity by identifying a series of conservation units, which include species, evolutionarily significant units (ESUs), management units (MUs), action units (AUs), and family nets (FNs). Although mitochondrial DNA (mtDNA) evolves 5–10 times faster than single‐copy nuclear DNA (scnDNA), it records few traces of contemporary events. Thus, mtDNA can be used to resolve taxonomic uncertainties and ESUs. Variable number of tandem repeats (VNTRs) evolve 100–1000 times faster than scnDNA and provide a powerful tool for analyzing recent and contemporary events. VNTR analysis techniques include polymerase chain reaction (PCR)‐based microsatellite assays and oligonucleotide probing. Size homoplasy problems in PCR‐based microsatellite assays can strongly affect the inference of recent population history. The high homozygosity in endangered species is reflected in a relatively low number and level of variability in microsatellite loci. This combined with “allelic dropout” and “misprinting” errors contributes to the generation of highly biased genetic data following analyses of natural populations. Thus, in conservation genetics, microsatellites are of limited use for identifying ESUs, MUs, and AUs. In contrast to PCR‐based microsatellite analysis, oligonucleotide probing avoids errors resulting from PCR amplification. It is particularly suitable for inferring recent population history and contemporary gene flow between fragmented subpopulations. Oligonucleotide fingerprinting generates individual‐specific DNA banding patterns and thus provides a highly precise tool for monitoring demography of natural populations. Hence, DNA fingerprinting is powerful for distinguishing ESUs, MUs, AUs, and FNs. The use of oligonucleotide fingerprinting and fecal DNA is opening new areas for conservation genetics.
Sequencing of oligosaccharides derivatized with benzylamine using electrospray ionization‐quadrupole time of flight‐tandem mass spectrometry
Authors: Morelle Willy , Michalski Jean‐Claude 
Published: July 2004

AbstractOligosaccharides were derivatized by reductive amination using benzylamine and analyzed by nanoelectrospray ionization‐quadrupole time of flight‐tandem mass spectrometry (nanoESI‐QTOF‐MS/MS) in the positive ion mode. The major signals were obtained under these conditions from the [M+H]+ions for all benzylamine‐derivatized oligosaccharides. To obtain structural information from these derivatized oligosaccharides, MS/MS was applied. Protonated molecular ions underwent extensive fragmentation, even under low‐energy collision‐induced dissociation. MS/MS spectra of [M+H]+ions are characterized by simple fragmentation patterns which result from cleavage of the glycosidic bonds and thus allow a straightforward interpretation. Fragmentation of the [M+H]+ions gave predominantly B‐ and Y‐type glycosidic fragments. A systematic study of various oligosaccharides showed that information on sugar sequence and branching could easily be obtained. Predictable and reproducible fragmentation patterns could be obtained in all cases. This derivatization procedure and mass spectrometric methodology were applied successfully to neutral and acidic glycans released from 10 μg of glycoproteins separated by gel electrophoresis. Moreover, the derivatives retain their sensitivity to exoglycosidases. Thus a series of sequential on‐target exoglycosidase treatments combined with matrix‐assisted laser desorption/ionization‐time of flight‐mass spectrometry (MALDI‐TOF‐MS) was found to be useful for the determination of structural features of the glycans released from proteins separated by gel electrophoresis such as the monosaccharide sequence, branching pattern, and anomeric configurations of the corresponding glycosidic linkages. Our strategy can be used successfully to assign the major glycans released from proteins separated by gel electrophoresis.
Aberrant expression of acute‐phase reactant proteins in sera and breast lesions of patients with malignant and benign breast tumors
Authors: Doustjalali Saeid R. , Yusof Rohana , Yip Cheng‐Har , Looi Lai‐Meng , Pillay Bhanumathy , Hashim Onn H. 
Published: July 2004

AbstractWe have analyzed unfractionated sera of newly diagnosed patients (n = 10) with breast carcinoma (BC), prior to treatment, and patients (n = 5) with fibrocystic disease of the breast (FDB) by two‐dimensional gel electrophoresis (2‐DE) and silver staining. The patients' 2‐DE serum protein profiles obtained were then subjected to image analysis and compared to similar data generated from sera of normal healthy female controls (n = 10) of the same range of age. The relative expression of α1‐antichymotrypsin (ACT), clusterin, and complement factor B was significantly higher in all BC patients as compared to normal controls. However, the expression of α1‐antitrypsin (AAT) in BC patients was apparently lower than that of the controls. Similar differential expression of ACT was detected in the FDB patients. The aberrant expression of the serum acute‐phase proteins of patients with BC and FDB was confirmed by competitive enzyme‐linked immunosorbent assay (ELISA). Similar altered proteins expression was also observed from immunohistochemical studies of malignant (n = 5) and benign (n = 5) breast lesions of the respective patients performed using antisera to the aberrantly expressed proteins. However, the malignant breast lesions were instead positively stained for AAT. The differential expression of the serum proteins was apparently abrogated when a six‐month follow‐up study was performed on nine of the BC patients subsequent to treatment.
Capillary electrophoresis sequencing of small ssDNA molecules versus the Ogston regime: Fitting data and interpreting parameters
Authors: Kopecka Katerina , Drouin Guy , Slater Gary W. 
Published: July 2004

AbstractWe study the mobility of short ssDNA fragments (approximately 30–500 bases) separated by capillary electrophoresis in entangled polymer solutions. Although this corresponds to what is commonly called the Ogston regime, the corresponding sieving concept has never been defined properly nor tested quantitatively. We consider three formulas that have been suggested to fit data in this range of ssDNA sizes, and we discuss how their free parameters are related to actual physical parameters. We test these formulas with new data obtained in our laboratory using a commercial poly‐N,N‐dimethylacrylamide sieving matrix. Our results show that all three formulas provide decent fits. However, the traditional Ogston equation produces fitting parameters that appear to lack physical meaning. Surprisingly, all three approaches predict that the effective pore size and fiber radius are almost equal. This is the first step towards the development of a systematic approach to optimizing sequencing systems for this size range.
Gene expression analysis of an integrin family of genes by systematic multiplex reverse transcription‐polymerase chain reaction
Authors: Yamamoto Miyako , Yamamoto Ami , Leung Patricia C. , Yamamoto Fumiichiro 
Published: July 2004

AbstractWe have established the systematic multiplex reverse transcription‐polymerase chain reaction (SM RT‐PCR) system of 26 members of the integrin family of genes, and used this system to investigate their expression in 25 different kinds of human adult tissues. A hierarchical clustering analysis of the tissue expression data illustrated clustering of functionally related tissues. Although the correlation was weak, bone marrow, thymus, and spleen were clustered, potentially confirming the role of certain integrin molecules in the immune response. We also investigated changes in integrin gene expression in cancer. Several differences were observed between normal and tumor, as well as between normal and cancer cell lines. The SM RT‐PCR experiments for the study of alternative splicing showed that most of the integrin genes analyzed exhibited fixed ratios of differentially spliced transcripts probably due to a tissue‐independent mechanism of splicing predetermined by the nucleotide sequences around the splicing donor and acceptor sites.
Evaluation and validation of the ABI 3700, ABI 3100, and the MegaBACE 1000 capillary array electrophoresis instruments for use with short tandem repeat microsatellite typing in a forensic environment
Authors: Koumi Pieris , Green Helen E. , Hartley Susan , Jordan Darren , Lahec Sharon , Livett Richard J. , Tsang Kam W. , Ward David M. 
Published: July 2004

AbstractThe demand for high‐throughput DNA profiling has increased with the introduction of national DNA databases and has led to the development of automated methods of short tandem repeat (STR) profile production; however, a potential bottleneck still exists at the gel electrophoresis stage. Capillary electrophoresis sequencers capable of processing 96 samples with considerably reduced manual intervention are now available. In this paper, we compare the ABI Prism 377 slab‐gel sequencer currently used by the Forensic Science Service with three leading capillary array electrophoresis instruments: the ABI Prism 3700, the Amersham MegaBACE 1000 and the 16‐capillary ABI Prism 3100. We describe the experiments used to evaluate and validate these platforms for forensic use with the STR multiplex Ampf/STR SGMplus [1, 2], along with comparative data from the ABI Prism 377 sequencer.
Polymer solutions and entropic‐based systems for double‐stranded DNA capillary electrophoresis and microchip electrophoresis
Authors: Xu Feng , Baba Yoshinobu 
Published: July 2004

AbstractWe give an overview of recent development of low‐viscosity polymer solutions and entropic trapping networks for double‐stranded DNA (dsDNA) separations by conventional capillary electrophoresis and microchip electrophoresis. Theoretical models for describing separation mechanisms, commonly used noncross‐linked polymer solutions, thermoresponsive (viscosity‐adjustable) polymer solutions, and novel entropic trapping networks are included. The thermoresponsive polymer solutions can be loaded at one temperature into microchannels at lower viscosities, and used in separation at another temperature at entanglement threshold concentrations and higher viscosities. The entropic‐based separations use only arrays of regular obstacles acting as size‐separations and do not need viscous polymer solutions. These progresses have potential in integration to automated capillary and microfluidic chip systems, enabling better reusability of separation microchannels, much shorter DNA separation times, and higher reproducibility due to less matrix degradation.
Separation and investigation of structure‐mobility relationships of insect oostatic peptides by capillary zone electrophoresis
Authors: Šolínová Veronika , Kašička Václav , Koval Dušan , Hlaváček Jan 
Published: July 2004

AbstractCapillary zone electrophoresis (CZE) has been applied to qualitative analysis, separation, and physicochemical characterization of synthetic insect oostatic peptides (IOPs) and their derivatives and fragments. Series of homologous IOPs were separated in three acidic background electrolytes (BGEs; pH 2.25, 2.30, 2.40) and an alkaline BGE (pH 8.1). Best separation was achieved in acid BGE composed of 100 mM H3PO4, 50 mM Tris, pH 2.25. The effective electrophoretic mobilities, μep, of all IOPs in four BGEs were determined and several semiempirical models correlating effective mobility with charge‐to‐size ratio (μep versus q/Mrk) were tested to describe the migration behavior of IOP in CZE. None of models was found to be unambiguously applicable for the whole set of 20 IOPs differing in size (dipeptide – decapeptide) and charge (−2 to +0.77 elementary charges). However, a high coefficient of correlation, 0.9993, was found for the subset of homologous series of IOPs with decreasing number of proline residues at C‐terminus, H‐Tyr‐Asp‐Pro‐Ala‐Prox‐OH, x = 6 – 0, for the dependence of μep on q/Mrk with k = 0.5 for IOPs as anions in alkaline BGE and with k = 2/3 for IOPs as cations in optimized acidic Tris‐phosphate BGE. From these dependences the probable structure of IOPs in solution could be predicted.
Refining the results of a whole‐genome screen based on 4666 microsatellite markers for defining predisposition factors for multiple sclerosis
Authors: Gödde René , Nigmatova Viktoria , Jagiello Peter , Sindern Eckhart , Haupts Michael , Schimrigk Sebastian , Epplen Jörg T. 
Published: July 2004

AbstractMultiple sclerosis (MS) is a demyelinating disease of the central nervous system with a complex genetic background. In order to identify loci associated with the disease, we had performed a genome screen initially using 6000 microsatellite markers in pooled DNA samples of 198 MS patients and 198 controls. Here, we report on the detailed reanalysis of this set of data. Distinctive features of microsatellites genotyped in pooled DNA causing false‐positive association or masking existing association were met by improved evaluation and refined correction factors in the statistical analyses. In order to assess potential errors introduced by DNA pooling and genotyping, we resurveyed the experiment in a subset of microsatellite markers using de novo‐composed DNA pools. True MS associations of markers were verified via genotyping all individual DNA samples comprised in the pools. Microsatellites share characteristically superb information content but they do not lend themselves to automation in very large scale formats. Especially after DNA pooling many artifacts of individual marker systems require special attention and treatment. Therefore, in the near future comprehensive whole‐genome screens may rather be performed by typing single nucleotide polymorphisms on chip‐based platforms.
Use of a native affinity ligand for the detection of G proteins by capillary isoelectric focusing with laser‐induced fluorescence detection
Authors: Cunliffe Jennifer M. , Liu Zhen , Pawliszyn Janusz , Kennedy Robert T. 
Published: July 2004

AbstractAffinity probe capillary isoelectric focusing (CIEF) with laser‐induced fluorescence was explored for detection of Ras‐like G proteins. In the assay, a fluorescent BODIPY® FL GTP analogue (BGTPγS) and G protein were incubated resulting in formation of BGTPγS‐G protein complex. Excess BGTPγS was separated from BGTPγS‐G protein complex by CIEF using a 3–10 pH gradient and detected in whole‐column imaging mode. In other cases, a single point detector was used to detect zones during the focusing step of CIEF using a 2.5–5 pH gradient. In this case, analyte peaks passed the detector in ∼ 5 min at an electric field of 350 V/cm. Detection during focusing allowed for more reproducible assays at shorter times but with a sacrifice in sensitivity compared to detection during mobilization. Resolution was adequate to separate BGTPγS‐Ras and BGTPγS‐Rab3A complexes. Formation of specific complexes was confirmed by adding GTPγS to samples containing BGTPγS‐G protein. GTPγS competed with BGTPγS for G protein binding sites resulting in decreased BGTPγS‐G protein peak heights. The concentrating effect of CIEF enabled detection limits of 30 pM.
Comprehensive two‐dimensional chromatography and capillary electrophoresis coupled with tandem time‐of‐flight mass spectrometry for high‐speed proteome analysis
Authors: Zhang Jie , Hu Hualing , Gao Mingxia , Yang Pengyuan , Zhang Xiangmin 
Published: July 2004

AbstractA comprehensive two‐dimensional capillary liquid chromatography and capillary zone electrophoresis system coupled with tandem matrix assisted laser desorption/ionization‐time of flight‐time of flight‐mass spectrometry (MALDI‐TOF‐TOF‐MS) proteomics analyzer is presented. Protein/peptide samples were separated by capillary high‐performance liquid chromatography (cHPLC). The effluents from cHPLC (the first dimension) were continuously transferred into capillary zone electrophoresis (CZE, the second dimension) through a novel valve‐free hydrodynamic sampling interface. The CZE effluents were mixed with α‐cyano‐4‐hydroxycinnamic acid (CHCA) matrix sheath flow via CE‐MALDI interface, and then directly deposited on the MALDI target at a 3 s time‐interval for further MS analysis. The high efficiency of the overall system was demonstrated by analysis of proteins in D20 (human hepatocellular carcinoma model in nude mice with high metastatic potential) liver cancer tissue. More than 300 proteins were identified, which proved the system potential for high‐throughput analysis and application in proteomics.
Separation of double‐stranded DNA fragments by capillary electrophoresis: Impacts of poly(ethylene oxide), gold nanoparticles, ethidium bromide, and pH
Authors: Chiou Shin‐Huei , Huang Ming‐Feng , Chang Huan‐Tsung 
Published: July 2004

AbstractThe separation of DNA by capillary electrophoresis using poly(ethylene oxide) (PEO) containing gold nanoparticles (GNPs) is presented. The impacts of PEO, GNPs, ethidium bromide (EtBr), and pH on the separation of double‐stranded DNA have been carefully explored. Using a capillary dynamically coated with 5.0% poly(vinylpyrrolidone) and filled with 0.2% PEO containing 0.3×GNPs (the viscosity less than 15 cP), we have demonstrated the separation of DNA markers V and VI within 5 min at pH 8.0 and 9.0. In terms of resolution and reproducibility, GNPs have a greater impact on the separation of DNA at pH 9.0. Resolution improvements for large DNA fragments (> 300 base pairs, bp) are greater than those for small ones in the presence of GNPs. It is important to point out that reproducibility is excellent (relative standard deviations for the migration times less than 0.5%) and thus no further dynamic coating is required in at least 20 consecutive runs in the presence of GNPs. Using 0.2% PEO (pH 9.0) containing 0.3×GNPs, the separation of DNA fragments ranging in size from 21 to 23130 bp was accomplished in 7 min. The results presented in this study show the advantage of PEO containing GNPs for DNA separation, including rapidity, high resolving power, excellent reproducibility, and ease of filling capillaries.