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Recent Progress (recent + progress)
Selected AbstractsRECENT PROGRESS IN ENDOSCOPY-BASED DIAGNOSIS OF HELICOBACTER PYLORI INFECTIONDIGESTIVE ENDOSCOPY, Issue 1 2001Tadashi Sato Numerous invasive and non-invasive tests are available in the detection of Helicobacter pylori. Endoscopy-based tests that include rapid urease test, histological examination and culture are important generally in the assessment of H. pylori status before eradication therapy. Recently, several new endoscopy-based diagnostic methods have been developed aiming at rapid and accurate detection of the organisms. It would be possible to diagnose H. pylori infection in treated patients by using these new highly sensitive tests. Although the diagnosis of H. pylori infection itself is possible by using non-invasive diagnostic tests, endoscopy-based tests provide not only the diagnosis of the organisms, but also the exclusive information such as treatment indications and the susceptibility for the antimicrobial drugs. Recently, new triple therapy including clarithromycin has been widely performed in Japan. Along with an increase in the prevalence of the antibiotic-resistant strains, culture may become a more important diagnostic method in the future. The inappropriate application of the tests may increase the potential risk of the misdiagnosis and the treatment failures. The diagnostic method should be selected by taking into account the circumstances in which a diagnosis is to be performed. [source] Recent Progress in Dielectric Barrier Discharges for Aerodynamic Flow ControlCONTRIBUTIONS TO PLASMA PHYSICS, Issue 1-2 2007G. I. Font Abstract Plasma actuators are electrical devices that use an atmospheric pressure dielectric barrier discharge for flow control. They have been employed successfully to promote boundary layer attachment. Simulations have been carried out of a plasma actuator using Direct-Simulation-Monte-Carlo and Particle-in-Cell methods. This work summarizes some recent results including: 1) the method by which force is imparted by the actuator to the neutral flow, 2) the effect of electronegative gasses, such as oxygen, and 3) the effects on the neutral flow of the plasma force. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Dealing with Landscape Heterogeneity in Watershed Hydrology: A Review of Recent Progress toward New Hydrological TheoryGEOGRAPHY COMPASS (ELECTRONIC), Issue 1 2009Peter A. Troch Predictions of hydrologic system response to natural and anthropogenic forcing are highly uncertain due to the heterogeneity of the land surface and subsurface. Landscape heterogeneity results in spatiotemporal variability of hydrological states and fluxes, scale-dependent flow and transport properties, and incomplete process understanding. Recent community activities, such as Prediction in Ungauged Basins of International Association of Hydrological Sciences, have recognized the impasse current catchment hydrology is facing and have called for a focused research agenda toward new hydrological theory at the watershed scale. This new hydrological theory should recognize the dominant control of landscape heterogeneity on hydrological processes, should explore novel ways to account for its effect at the watershed scale, and should build on an interdisciplinary understanding of how feedback mechanisms between hydrology, biogeochemistry, pedology, geomorphology, and ecology affect catchment evolution and functioning. [source] Recent Progress in n-Channel Organic Thin-Film TransistorsADVANCED MATERIALS, Issue 12 2010Yugeng Wen Abstract Particular attention has been focused on n-channel organic thin-film transistors (OTFTs) during the last few years, and the potentially cost-effective circuitry-based applications in flexible electronics, such as flexible radiofrequency identity tags, smart labels, and simple displays, will benefit from this fast development. This article reviews recent progress in performance and molecular design of n-channel semiconductors in the past five years, and limitations and practicable solutions for n-channel OTFTs are dealt with from the viewpoint of OTFT constitution and geometry, molecular design, and thin-film growth conditions. Strategy methodology is especially highlighted with an aim to investigate basic issues in this field. [source] Recent Progress on Silica Coating of Nanoparticles and Related NanomaterialsADVANCED MATERIALS, Issue 11 2010Andrés Guerrero-Martínez Abstract In recent years, new strategies for silica coating of inorganic nanoparticles and organic nanomaterials, which differ from the classical methodologies, have emerged at the forefront of materials science. Silica as a coating material promises an unparalleled opportunity for enhancement of colloidal properties and functions by using core,shell rational designs and profiting from its synthetic versatility. This contribution provides a brief overview of recent progress in the synthesis of silica-coated nanomaterials and their significant impact in different areas such as spectroscopy, magnetism, catalysis, and biology. [source] Recent Progress in Exploring Magnetocaloric MaterialsADVANCED MATERIALS, Issue 45 2009B. G. Shen Abstract The magnetic refrigeration technique based on the magnetocaloric effect (MCE) has attracted increasing interest because of its high efficiency and environment friendliness. In this article, our recent progress in exploring effective MCE materials is reviewed with emphasis on the MCE in the LaFe13,xSixbased alloys discovered by us. These alloys show large entropy changes over a wide temperature range near room temperature. The effects of magnetic rare-earth doping, interstitial atoms and high pressure on the MCE have been systematically studied. Special issues, such as appropriate approaches to determining the MCE associated with the first-order magnetic transition, the depression of magnetic and thermal hysteresis, and the key factors determining the magnetic exchange in alloys of this kind, are discussed. The applicability of giant MCE materials to magnetic refrigeration near ambient temperature is evaluated. A brief review of other materials with significant MCE is also presented. [source] Recent Progress in GaN-Based Light-Emitting DiodesADVANCED MATERIALS, Issue 45 2009Haiqiang Jia Abstract In the last few years the GaN-based white light-emitting diode (LED) has been remarkable as a commercially available solid-state light source. To increase the luminescence power, we studied GaN LED epitaxial materials. First, a special maskless V-grooved c -plane sapphire was fabricated, a GaN lateral epitaxial overgrowth method on this substrate was developed, and consequently GaN films are obtained with low dislocation densities and an increased light-emitting efficiency (because of the enhanced reflection from the V-grooved plane). Furthermore, anomalous tunneling-assisted carrier transfer in an asymmetrically coupled InGaN/GaN quantum well structure was studied. A new quantum well structure using this effect is designed to enhance the luminescent efficiency of the LED to ,72%. Finally, a single-chip phosphor-free white LED is fabricated, a stable white light is emitted for currents from 20 to 60,mA, which makes the LED chip suitable for lighting applications. [source] Recent Progress in Syntheses and Applications of Dumbbell-like NanoparticlesADVANCED MATERIALS, Issue 30 2009Chao Wang Abstract This paper reviews the recent research progress in the syntheses and applications of dumbbell-like nanoparticles (NPs). It first describes the general synthesis of dumbbell-like NPs that contain noble metal and magnetic NPs/or quantum dots. It then outlines the interesting optical and magnetic properties found in these dumbbell NPs. The review further highlights several exciting application potentials of these NPs in catalysis and biomedicine. [source] Recent Progress in Polymer Solar Cells: Manipulation of Polymer:Fullerene Morphology and the Formation of Efficient Inverted Polymer Solar CellsADVANCED MATERIALS, Issue 14-15 2009Li-Min Chen Abstract Polymer morphology has proven to be extremely important in determining the optoelectronic properties in polymer-based devices. The understanding and manipulation of polymer morphology has been the focus of electronic and optoelectronic polymer-device research. In this article, recent advances in the understanding and controlling of polymer morphology are reviewed with respect to the solvent selection and various annealing processes. We also review the mixed-solvent effects on the dynamics of film evolution in selected polymer-blend systems, which facilitate the formation of optimal percolation paths and therefore provide a simple approach to improve photovoltaic performance. Recently, the occurrence of vertical phase separation has been found in some polymer:fullerene bulk heterojunctions.1,3 The origin and applications of this inhomogeneous distribution of the polymer donor and fullerene acceptor are addressed. The current status and device physics of the inverted structure solar cells is also reviewed, including the advantage of utilizing the spontaneous vertical phase separation, which provides a promising alternative to the conventional structure for obtaining higher device performance. [source] Chiral Tetraaza Ligands in Asymmetric Catalysis: Recent ProgressADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11 2003Fonseca, María Hechavarría Abstract Nitrogen-containing ligands have become very popular in asymmetric catalysis, due to their robustness and availability in comparison to phosphines. Nitrogen-containing ligands are used in homogeneous catalysis, but they are suitable for heterogeneous processes, too. In this article we focus on chiral ligands with four nitrogen atoms and summarize recent progress achieved with these compounds in asymmetric catalysis. [source] Recent Progress in Arabidopsis Research in China: A PrefaceJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 1 2006Zhi-Hong Xu First page of article [source] Biotechnology of the Banana: A Review of Recent ProgressPLANT BIOLOGY, Issue 5 2000G. R. Rout Abstract: A number of biotechnological tools have been developed which could help breeders to evolve new plant types to meet the demand of the food industry in the next century. Available techniques for the transfer of genes could significantly shorten the breeding procedures and overcome some of the agronomic and environmental problems which would otherwise not be possible through conventional methods. In vitro protocols have been standardized to allow commercially viable propagation of desired clones of Musa. An overview of the regeneration of banana by direct and indirect organogenesis, and somatic embryogenesis is presented in this article. In addition, the use of several other biotechnological techniques to enrich the genome of banana, such as selection of somaclonal variants, screening for various useful characteristics, cryopreservation, genetic transformation and molecular genetics are reviewed. In conclusion, the improvement of banana through modern biotechnology should help ensure food security by stabilizing production levels in sustainable cropping systems geared towards meeting domestic and export market demands. [source] Recent Progress and New Perspectives in Studying T Cell Responses to AllograftsAMERICAN JOURNAL OF TRANSPLANTATION, Issue 5 2010A. Valujskikh Studies in the past decade advanced our understanding of the development, execution and regulation of T-cell-mediated allograft rejection. This review outlines recent progress and focuses on three major areas of investigation that are likely to guide the development of graft-prolonging therapies in the future. The discussed topics include the contribution of recently discovered molecules to the activation and functions of alloreactive T cells, the emerging problem of alloreactive memory T cells and recently gained insights into the old question of transplantation tolerance. [source] Mycophenolate Mofetil and Calcineurin-Inhibitor Reduction: Recent ProgressAMERICAN JOURNAL OF TRANSPLANTATION, Issue 11 2009Josep M. Grinyó Mycophenolate mofetil (MMF) in combination with calcineurin inhibitors (CNIs) has greatly contributed to acute rejection rate reduction. Because of its immunosuppressive potency it was initially thought that MMF would help in reducing/avoiding CNI-related nephrotoxicity. Elective avoidance of CNI in induction and maintenance MMF-based immunosuppression has resulted in an increased risk for acute and chronic rejection. A recent meta-analysis suggests that CNI elimination in patients on MMF with progressive renal dysfunction is associated with a better outcome, although more data are needed to support any recommendation. So far, the more conservative approach involving CNI minimization with MMF has been associated with amelioration of renal function and low risk for rejection, providing an adequate risk/benefit balance. However, MMF with belatacept might pave the way for CNI-free induction and maintenance immunosuppression. Meanwhile, the assessment of immunological risk by new monitoring tools could be a prerequisite to further implement such CNI sparing strategies. [source] Mycophenolate Blood Level Monitoring: Recent ProgressAMERICAN JOURNAL OF TRANSPLANTATION, Issue 7 2009T. Van Gelder The concentration,effect relationship for mycophenolic acid (MPA), and the high variability in MPA concentrations in patients on standard dose mycophenolate mofetil (MMF) therapy, for some centers has provided enough evidence to implement therapeutic drug monitoring (TDM) for MMF in daily practice. Two randomized trials Adaption de Posologie du MMF en Greffe Renale (APOMYGRE) and fixed-dose versus concentration controlled (FDCC) investigated the added benefit of TDM for MMF in renal transplant recipients. The APOMYGRE study showed a significant reduction in the incidence of acute rejection in concentration-controlled patients, while the FDCC study had a negative outcome, despite a similar study design. Although it was expected that these prospective trials would give the final answer to the question of whether or not TDM for MMF would be of benefit, it seems that the studies have not had much impact on patient management. Several trials have shown the importance of early adequate exposure to MPA in the first week after transplantation. As it will be hard to improve MPA exposure with TDM, this early, ongoing study now investigates the use of an increased starting dose. The increased starting dose will avoid underexposure to MPA in higher proportions of patients shortly after transplantation but may result in more toxicity in patients with MPA exposures exceeding the upper threshold of the therapeutic window. [source] Recent Progress in Artificial Organs and Regenerative Medicine in JapanARTIFICIAL ORGANS, Issue 5 2010Yoshinori Mitamura First page of article [source] Recent Progress in Artificial Organ Research at Tohoku UniversityARTIFICIAL ORGANS, Issue 1 2003Tomoyuki Yambe Abstract: Tohoku University has developed various artificial organs over the last 30 years. Pneumatic driven ventricular assist devices with a silicone ball valve have been designed by the flow visualization method, and clinical trials have been performed in Tohoku University Hospital. On the basis of these developments, a pneumatic driven total artificial heart has been developed and an animal experimental evaluation was conducted. The development of artificial organs in Tohoku University has now progressed to the totally implantable type using the transcutaneous energy transmission system with amorphous fibers for magnetic shielding. Examples of implantable systems include a vibrating flow pump for ventricular assist device, an artificial myocardium by the use of shape memory alloy with Peltier elements, and an artificial sphincter for patients with a stoma. An automatic control system for artificial organs had been developed for the ventricular assist devices including a rotary blood pump to avoid suction and to maintain left and right heart balance. Based upon the technology of automatic control algorithm, a new diagnostic tool for evaluating autonomic nerve function has been developed as a branch of artificial organ research and this new machine has been tested in Tohoku University Hospital. Tohoku University is following a variety of approaches aimed at innovation in artificial organs and medical engineering fields. [source] Recent Progress in Biomolecular EngineeringBIOTECHNOLOGY PROGRESS, Issue 1 2000Dewey D. Y. Ryu During the next decade or so, there will be significant and impressive advances in biomolecular engineering, especially in our understanding of the biological roles of various biomolecules inside the cell. The advances in high throughput screening technology for discovery of target molecules and the accumulation of functional genomics and proteomics data at accelerating rates will enable us to design and discover novel biomolecules and proteins on a rational basis in diverse areas of pharmaceutical, agricultural, industrial, and environmental applications. As an applied molecular evolution technology, DNA shuffling will play a key role in biomolecular engineering. In contrast to the point mutation techniques, DNA shuffling exchanges large functional domains of sequences to search for the best candidate molecule, thus mimicking and accelerating the process of sexual recombination in the evolution of life. The phage-display system of combinatorial peptide libraries will be extensively exploited to design and create many novel proteins, as a result of the relative ease of screening and identifying desirable proteins. Even though this system has so far been employed mainly in screening the combinatorial antibody libraries, its application will be extended further into the science of protein-receptor or protein-ligand interactions. The bioinformatics for genome and proteome analyses will contribute substantially toward ever more accelerated advances in the pharmaceutical industry. Biomolecular engineering will no doubt become one of the most important scientific disciplines, because it will enable systematic and comprehensive analyses of gene expression patterns in both normal and diseased cells, as well as the discovery of many new high-value molecules. When the functional genomics database, EST and SAGE techniques, microarray technique, and proteome analysis by 2-dimensional gel electrophoresis or capillary electrophoresis in combination with mass spectrometer are all put to good use, biomolecular engineering research will yield new drug discoveries, improved therapies, and significantly improved or new bioprocess technology. With the advances in biomolecular engineering, the rate of finding new high-value peptides or proteins, including antibodies, vaccines, enzymes, and therapeutic peptides, will continue to accelerate. The targets for the rational design of biomolecules will be broad, diverse, and complex, but many application goals can be achieved through the expansion of knowledge based on biomolecules and their roles and functions in cells and tissues. Some engineered biomolecules, including humanized Mab's, have already entered the clinical trials for therapeutic uses. Early results of the trials and their efficacy are positive and encouraging. Among them, Herceptin, a humanized Mab for breast cancer treatment, became the first drug designed by a biomolecular engineering approach and was approved by the FDA. Soon, new therapeutic drugs and high-value biomolecules will be designed and produced by biomolecular engineering for the treatment or prevention of not-so-easily cured diseases such as cancers, genetic diseases, age-related diseases, and other metabolic diseases. Many more industrial enzymes, which will be engineered to confer desirable properties for the process improvement and manufacturing of high-value biomolecular products at a lower production cost, are also anticipated. New metabolites, including novel antibiotics that are active against resistant strains, will also be produced soon by recombinant organisms having de novo engineered biosynthetic pathway enzyme systems. The biomolecular engineering era is here, and many of benefits will be derived from this field of scientific research for years to come if we are willing to put it to good use. [source] Recent Progress in Strategies for the Creation of Protein-Based Fluorescent BiosensorsCHEMBIOCHEM, Issue 16 2009Hangxiang Wang Abstract The creation of novel bioanalytical tools for the detection and monitoring of a range of important target substances and biological events in vivo and in vitro is a great challenge in chemical biology and biotechnology. Protein-based fluorescent biosensors,integrated devices that convert a molecular-recognition event to a fluorescent signal,have recently emerged as a powerful tool. As the recognition units various proteins that can specifically recognize and bind a variety of molecules of biological significance with high affinity are employed. For the transducer, fluorescent proteins, such as green fluorescent protein (GFP) or synthetic fluorophores, are mostly adopted. Recent progress in protein engineering and organic synthesis allows us to manipulate proteins genetically and/or chemically, and a library of such protein scaffolds has been significantly expanded by genome projects. In this review, we briefly describe the recent progress of protein-based fluorescent biosensors on the basis of their platform and construction strategy, which are primarily divided into the genetically encoded fluorescent biosensors and chemically constructed biosensors. [source] Dynamic study of cerebral bioenergetics and brain function using in vivo multinuclear MRS approachesCONCEPTS IN MAGNETIC RESONANCE, Issue 2 2005Wei Chen Abstract One of the greatest merits of nuclear magnetic resonance (NMR) methodology used in biomedical research and clinical settings is its capability of measuring various physiological parameters in vivo. Besides MR imaging (MRI), which has been routinely applied to obtain vital information in living organs at normal and diseased states, in vivo MR spectroscopy (MRS) provides an invaluable tool for determining metabolites, chemical reaction rates, bioenergetics, and their dynamic changes in the human and animals noninvasively. These MRS capabilities are further enhanced at high/ultrahigh magnetic fields because of significant gain in NMR detection sensitivity and improvement in the spectral resolution. Recent progress has shown that in vivo MRS holds great promise in many biomedical research areas,in particular, brain research. This article provides a broad review of (i) in vivo multinuclear MRS approaches, (ii) advanced MRS methodologies, and (iii) MRS applications for determining cerebral metabolism as well as bioenergetics at resting brain state and their dynamic changes in response to brain activation. © 2005 Wiley Periodicals, Inc. Concepts Magn Reson Part A 27A: 84-121, 2005 [source] Extrapolation of the W7-X Magnet System to Reactor SizeCONTRIBUTIONS TO PLASMA PHYSICS, Issue 8 2010F. Schauer Abstract The fusion experiment Wendelstein 7-X (W7-X), presently under construction at the Greifswald branch institute of IPP, shall demonstrate the reactor potential of a HELIAS stellarator. HELIAS reactors with three, four and five periods have been studied at IPP since many years. With a plasma axis induction of 5 T, corresponding to about 10 T maximal induction at the coil, it was shown that such reactors are feasible. Now the possibility is being investigated to increase the conductor induction up to the 12 T , range, corresponding to > 5.5 T at the plasma axis. This improves the stellarator confinement properties but does not change the basic physics with respect to the previously analyzed machines. In particular the 5periodic HELIAS type, HSR5, is considered which evolves from W7-X by linear scaling of the main dimensions by a factor of four. Recent progress in superconductor technology and the extensive development work performed for ITER are taken into account. The latter is particularly relevant since by coincidence the circumferences of the HSR5 and the ITER toroidal field coils are practically the same. For the presented 12 T reactor version, the HSR50a, also the conductor and structural requirements are comparable to the corresponding ITER specifications. Therefore, advantage can be taken of these similarities for the stellarator reactor magnet design. The input was provided by the new code "MODUCO" which was developed for interactive coil layout. It is based on Bézier curve approximations and includes the computation of magnetic surfaces and forces (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] A challenge for regenerative medicine: Proper genetic programming, not cellular mimicryDEVELOPMENTAL DYNAMICS, Issue 12 2007Angie Rizzino Abstract Recent progress in stem cell biology and the reprogramming of somatic cells to a pluripotent phenotype has generated a new wave of excitement in regenerative medicine. Nonetheless, efforts aimed at understanding transdifferentiation, dedifferentiation, and the plasticity of cells, as well as the ability of somatic cells to be reprogrammed, has raised as many questions as those that have been answered. This review proffers the argument that many reports of transdifferentiation, dedifferentiation, and unexpected stem cell plasticity may be due to aberrant processes that lead to cellular look-alikes (cellular mimicry). In most cases, cellular look-alikes can now be identified readily by monitoring gene expression profiles, as well as epigenetic modifications of DNA and histone proteins of the cells involved. This review further argues that progress in regenerative medicine will be significantly hampered by failing to address the issue of cellular look-alikes. Developmental Dynamics 236:3199,3207, 2007. © 2007 Wiley-Liss, Inc. [source] Growth hormone secretagogue receptor antagonists as potential therapeutic agents for obesityDRUG DEVELOPMENT RESEARCH, Issue 2 2005Hongyu Zhao Abstract Safe and efficacious medicines for obesity treatment are greatly needed. As an endogenous ligand of growth hormone secretagogue receptor 1a (GHS-R 1a), ghrelin is the only known circulating orexigen. Administration of ghrelin causes food intake and body weight increase in both rodents and humans, whereas inhibiting its actions by antibodies, peptide antagonists, and anti-sense oligonucleotides leads to decreased food intake and weight loss. Recent progress in developing nonpeptidyl small molecule GHS-R antagonists is reviewed in this article. Drug Dev. Res. 65:50,54, 2005. © 2005 Wiley-Liss, Inc. [source] Electroactivity of Nonconjugated Proteins and Peptides.ELECTROANALYSIS, Issue 23 2007Towards Electroanalysis of All Proteins Abstract Present proteomics and biomedicine require sensitive analytical methods for all proteins. Recent progress in electrochemical analysis of peptides and proteins based on their intrinsic electroactivity is reviewed. Tyrosine and/or tryptophan-containing proteins are oxidizable at carbon electrodes. At mercury electrodes all peptides and proteins (about 13 peptides and >25 proteins were tested) produce chronopotentiometric peak H at nanomolar concentrations. This peak is sensitive to changes in protein structure. Microliter sample volumes are sufficient for the analysis. Electrochemical methods can be used in studies of nucleic acid-protein interactions and can be applied in biomedicine. Examples of such applications in neurogenerative diseases and cancer are presented. [source] Recent progress in the use of soluble ionic polymers as pseudostationary phases for electrokinetic chromatographyELECTROPHORESIS, Issue 23-24 2004Christopher P. Palmer Abstract This review concerns the development, characterization, and application of soluble ionic polymeric materials as pseudostationary phases for electrokinetic chromatography since 2002. Cationic polymers, anionic siloxanes, polymerized surfactants (micelle polymers), and chiral polymers are considered. The use of stable suspensions of polymer nanoparticles in electrokinetic chromatography is also reviewed. [source] Recent progress in the development, characterization and application of polymeric pseudophases for electrokinetic chromatographyELECTROPHORESIS, Issue 22-23 2002Christopher P. Palmer Abstract This review article details the development, characterization and application of polymeric materials as pseudostationary phases for electrokinetic chromatography over the past two years. Recent developments in cationic polymers and anionic siloxane, acrylamide and polymerized surfactants (micelle polymers) are reviewed. Also reviewed is recent progress in the development and characterization of chiral polymeric phases for chiral separations by electrokinetic chromatography, and application of a polymeric pseudophase with electrospray ionization mass spectrometric detection. [source] Recent progress in enantiomeric separation by capillary electrochromatographyELECTROPHORESIS, Issue 22-23 2002Jingwu Kang Abstract Recent progress in enantiomeric separations by capillary electrochromatography (CEC) is reviewed. The development of simple and robust CEC column technologies plays an important role for popularization of CEC. During the last several years, various approaches for the preparation of enantioselective columns have been reported. Currently, the monolithic column technology (continuous beds) represents the most advanced approach for the preparation of CEC columns. The development of new chiral stationary phase used for CEC is another important issue in this field. Fundamental investigations on electrochromatographic behaviors of various CSPs are necessary in order to understand the separation mechanism and thus improve the separation performance. Some chiral stationary phases performed better under nonaqueous CEC conditions than reversed-phase conditions. Coupling CEC with mass spectrometry (MS) provides a powerful tool for enantiomeric separation. Finally, some applications of enantiomeric separation by CEC are summarized. [source] Immunopathogenesis of cholestatic autoimmune liver diseasesEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 1 2001J. Medina Primary biliary cirrhosis and primary sclerosing cholangitis are well recognized chronic cholestatic liver diseases that are considered to have an autoimmune basis. Recent progress in the study of autoimmune liver diseases has improved the recognition and characterization of these conditions. An important component of this progress has been the identification of liver disease-associated autoantibodies and their respective target antigens, and the development of specific assays for these autoantibodies. In addition, some nonhumoral immunological findings imply an involvement of specific immunopathogenic mechanisms in the development of these conditions. Furthermore, immunogenetic factors associated with increased susceptibility to some of these diseases have been identified. This article reviews the most relevant information relating to the postulated autoimmune pathogenesis of these diseases, with special emphasis on their associated humoral and cellular immunological abnormalities and immunopathogenetic factors. Some of the remaining important unresolved issues relating to the pathogenesis of these diseases, that need to be addressed in further research, are highlighted. [source] Weak agonist self-peptides promote selection and tuning of virus-specific T cellsEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 3 2003Samuel Abstract Recent progress has begun to define the interactions and signaling pathways that are triggered during positive selection. To identify and further examine self-peptides that can mediate positive selection, we searched a protein-database to find peptides that have minimal homology with the viral peptide (p33) that activates a defined P14 transgenic TCR. We identified four peptides that could bind the restriction element H-2Db and induce proliferation of P14 transgenic splenocytes at high concentration. Two of the four peptides (DBM and RPP) were able to positively select thevirus-specific TCR in fetal thymic organ culture but were unable to induce clonal deletion. Reverse-phase HPLC and mass spectrometry demonstrated that these peptides were presented by H-2Db molecules on thymic epithelial cell lines. We also examined whether the selecting ligands altered T cell responsiveness in vitro. DBM-selected T cells lost their ability to respond to the positively selecting ligand DBM, whereas RPP-selected T cells only retainrd their ability to respond to high concentrations of RPP. These results demonstrate that self-peptides that mediate positiveselection can differentially "tune" the activation threshold of T cells and alter the functional repertoire of T cells. [source] Polyamines and hair: a couple in search of perfectionEXPERIMENTAL DERMATOLOGY, Issue 9 2010Yuval Ramot Please cite this paper as: Polyamines and hair: a couple in search of perfection. Experimental Dermatology 2010; 19: 784,790. Abstract:, Polyamines (spermidine, putrescine and spermine) are multifunctional cationic amines that are indispensable for cellular proliferation; of key significance in the growth of rapidly regenerating tissues and tumors. Given that the hair follicle (HF) is one of the most highly proliferative organs in mammalian biology, it is not surprising that polyamines are crucial to HF growth. Indeed, growing (anagen) HFs show the highest activity of ornithine decarboxylase (ODC), the rate-limiting enzyme of polyamine biosynthesis, while inhibition of ODC, using eflornithine, results in a decreased rate of excessive facial hair growth in vivo and inhibits human scalp hair growth in organ culture. In sheep, manipulation of dietary intake of polyamines also results in altered wool growth. Polyamine-containing nutraceuticals have therefore been proposed as promoters of human hair growth. Recent progress in polyamine research, coupled with renewed interest in the role of polyamines in skin biology, encourages one to revisit their potential roles in HF biology and highlights the need for a systematic evaluation of their mechanisms of action and clinical applications in the treatment of hair disorders. The present viewpoint essay outlines the key frontiers in polyamine-related hair research and defines the major open questions. Moreover, it argues that a renaissance in polyamine research in hair biology, well beyond the inhibition of ODC activity in hirsutism therapy, is important for the development of novel therapeutic strategies for the manipulation of human hair growth. Such targets could include the manipulation of polyamine biosynthesis and the topical administration of selected polyamines, such as spermidine. [source] | ||||||||||||||||||||||||||||||||||||||||