bluuebunny/crossref_metadata_2025_split huggingface dataset:
Actin polymerization modulates CD44 surface expression, MMP‐9 activation, and osteoclast function
Authors: Samanna V. , Ma T. , Mak T.W. , Rogers M. , Chellaiah M.A. 
Published: May 2007

AbstractCD44 and MMP‐9 are implicated in cell migration. In the current study, we tested the hypothesis that actin polymerization is critical for CD44 surface expression and MMP‐9 activity on the cell surface. To understand the underlying molecular mechanisms involved in CD44 surface expression and MMP‐9 activity on the cell surface, osteoclasts were treated with bisphosphonate (BP) alendronate, cytochalasin D (Cyt D), and a broad‐spectrum MMP inhibitor (GM6001). BP has been reported to block the mevalonate pathway, thereby preventing prenylation of small GTPase signaling required for actin cytoskeleton modulation. We show in this study that osteoclasts secrete CD44 and MMP‐9 into the resorption bay during migration and bone resorption. Results indicate that actin polymerization is critical for CD44 surface expression and osteoclast function. In particular, the surface expression of CD44 and the membrane activity of MMP‐9 are reduced in osteoclasts treated with alendronate and Cyt D despite the membrane levels of MMP‐9 being unaffected. Although GM6001 blocked MMP‐9 activity, osteoclast migration, and bone resorption, the surface levels of CD44 were unaffected. We suggest that the surface expression of CD44 requires actin polymerization. Disruption of podosome and actin ring structures by Cyt D and alendronate not only resulted in reduced localization of MMP‐9 in these structures but also in osteoclast migration and bone resorption. These results suggest that inhibition of actin polymerization by alendronate and Cyt D is effective in blocking CD44/MMP‐9 complex formation on the cell surface, secretion of active form of MMP‐9, and osteoclast migration. CD44/MMP‐9 complex formation may signify a unique motility‐enhancing signal in osteoclast function. J. Cell. Physiol. 213:710–720. © 2007 Wiley‐Liss, Inc.
Transient receptor potential vanilloid 1 activation induces inflammatory cytokine release in corneal epithelium through MAPK signaling
Authors: Zhang Fan , Yang Hua , Wang Zheng , Mergler Stefan , Liu Hongshan , Kawakita Tetsuya , Tachado Souvenir D. , Pan Zan , Capó‐Aponte José E. , Pleyer Uwe , Koziel Henry , Kao Winston W.Y. , Reinach Peter S. 
Published: May 2007

AbstractIn certain epithelial tissues, activation of transient receptor potential (TRP) vanilloid subtype 1 (TRPV1) by noxious stimuli induces pro‐inflammatory cytokine release, which helps to mitigate the challenge. While the corneal epithelium elicits such responses to a variety of challenges, it remains unknown whether TRPV1 mediates pro‐inflammatory cytokine secretion. Accordingly, we probed for TRPV1 expression and function in human (HCEC) and rabbit corneal epithelial cell (RCEC) lines, in their primary counterparts, and in human and mouse corneal epithelium in situ. Cell membrane and perinuclear TRPV1 expression was detected in all preparations and its identity verified by Western blot analysis. Capsaicin (CAP) (1–10 µM) increased nonselective cation channel whole cell currents (2.5‐fold ± 0.5‐fold between −60 and 130 mV), resulting in calcium transients that were fully blocked by the TRPV1 antagonists capsazepine (CPZ) and ruthenium red, or removal of extracellular calcium. Another signaling event involved transient activation of global mitogen‐activated protein kinase (MAPK) superfamily, which was followed by up to 3.3‐ and 9‐fold increases in interleukins (IL)‐6 and ‐8 release, respectively. Such increases in inflammatory mediators' release were suppressed by exposure to CPZ or MAPK inhibitors, or removal of Ca2+. Taken together, TRPV1 receptors may play a role in mediating corneal epithelial inflammatory mediator secretion and subsequent hyperalgesia. J. Cell. Physiol. 213:730–739. © 2007 Wiley‐Liss, Inc.
Anomeric information obtained from a series of synthetic trisaccharides using energy resolved mass spectra
Authors: Daikoku Shusaku , Ako Takuro , Kurimoto Ayako , Kanie Osamu 
Published: May 2007

AbstractThe majority of structural investigations of oligosaccharides based on mass spectrometry use naturally occurring oligosaccharides, which do not allow extracting any common feature associated with anomeric structures and linkage positions. In order to address the issue to find such characteristics possibly contained in oligosaccharide structure, a synthetic combinatorial trisaccharide library was analyzed. The trisaccharides used in the analysis consisted of L‐fucose, D‐galactose and D‐glucose, in which individual glycosidic linkages existed in either α‐ or β‐anomers. The analysis of energy‐resolved mass spectra (ERMS) and the scattered plot analysis of some parameters obtained from ERMS for a series of trisaccharides revealed that lower activation energy was required for the dissociation of α‐glycosides of these sugars compared to those of the corresponding β‐anomers. It is suggested that this finding may be useful in structural analysis of natural oligosaccharides. Copyright © 2007 John Wiley & Sons, Ltd.
A sensitive and selective liquid chromatography‐tandem mass spectrometry method for the simultaneous quantification of actinomycin‐D and vincristine in children with cancer
Authors: Lee James I. , Skolnik Jeffrey M. , Barrett Jeffrey S. , Adamson Peter C. 
Published: May 2007

AbstractWe describe a selective and a highly sensitive assay for actinomycin‐D (Act‐D) and vincristine (VCR) in plasma employing high‐performance liquid chromatography‐tandem mass spectrometry (HPLC‐MS/MS) detection. The intraday precision (as defined by the coefficient of variation, CV) based on the standard deviation of replicates of quality control samples ranged from 4.9 to 7.5% and 6.5 to 11.3% with accuracy ranging from 90.7 to 98.1% and 91.2 to 103% for Act‐D and VCR, respectively. The interday precision ranged from 7.2 to 10.0% and 11.3 to 13.0% and the accuracy ranged from 94.3 to 102% and 90.7 to 91.6% for Act‐D and VCR, respectively. Stability studies showed that Act‐D and VCR were stable both during the assay procedure and long‐term storage. The lower limit of quantitation (LLOQ) for both Act‐D and VCR was 0.05 ng/ml. The analytical method showed excellent sensitivity, precision, and accuracy. This method is robust and is being successfully employed in a pharmacokinetic study of these agents in children with cancer, and is expected to support several ongoing and future pediatric trials. Copyright © 2007 John Wiley & Sons, Ltd.
Hollow‐fiber liquid‐phase microextraction prior to low‐temperature electrothermal vaporization ICP‐MS for trace element analysis in environmental and biological samples
Authors: Xia Linbo , Wu Yunli , Hu Bin 
Published: May 2007

AbstractA new method of hollow‐fiber liquid‐phase microextraction (HF‐LPME) prior to electrothermal vaporization (ETV) inductively coupled plasma mass spectrometry (ICP‐MS) determination of trace Cu, Zn, Pd, Cd, Hg, Pb and Bi, based on gaseous compounds introduction into the plasma as their diethyldithiocarbmate (DDTC) chelates, was developed. The use of the reagent DDTC as chemical modifier could not only enhance the analytical signals, but also decrease the vaporization temperature. At a temperature of 1300 °C, trace Cu, Zn, Pd, Cd, Hg, Pb and Bi can be vaporized completely into the ICP. The factors affecting the formation of the chelates and their vaporization behaviors were investigated in detail, and the microextraction conditions were optimized. Under the optimized conditions, the detection limits of the proposed method were 12.4, 28.7, 7.9, 4.5, 3.3, 4.8 and 1.6 pg ml−1 for Cu, Zn, Pd, Cd, Hg, Pb and Bi, respectively. Enrichment factors of 305, 284, 24, 29, 20, 73 and 43 could be achieved within 15 min of extraction time, and the relative standard deviations (RSDs) for the seven determinations of 0.5 ng ml−1 of target analytes were 8.8, 6.9, 7.1, 9.4, 10.2, 6.1 and 10.8%, respectively. The newly developed method has been applied to the determination of trace Cu, Zn, Pd, Cd, Hg, Pb and Bi in environmental water and human serum samples, and the recoveries for the spiked samples were in the range of 88–116%. In order to validate this method, two certified reference materials, GBW08501 peach leaves and GBW(E)080040 seawater, were analyzed, and the determined values were in good agreement with the certified values. Copyright © 2007 John Wiley & Sons, Ltd.
Metabolomic investigation of CLN6 neuronal ceroid lipofuscinosis in affected South Hampshire sheep
Authors: Pears Michael R. , Salek Reza M. , Palmer David N. , Kay Graham W. , Mortishire‐Smith Russell J. , Griffin Julian L. 
Published: May 2007

AbstractThe neuronal ceroid lipofuscinoses (NCLs; Batten disease) are a group of fatal inherited neurodegenerative diseases in humans and animals distinguished by a common clinical pathology, characteristic storage body accumulation in cells, and gross brain atrophy. An 1H NMR spectroscopy‐ and GC‐MS‐based metabolomic investigation of changes in the cerebellum, frontal and occipital lobes, and cerebrospinal fluid (CSF) of CLN6 NCL affected South Hampshire sheep charted changes from the preclinical state to advanced disease. Glutamine and succinate concentrations increased in all brain regions in affected sheep relative to controls, whereas concentrations of aspartate, acetate, glutamate, N‐acetyl aspartate (NAA), and γ‐aminobutyric acid (GABA) decreased. Changes in the concentrations of inositols, NAA, and GABA were consistent with glial cell activation and neurodegeneration beginning in the frontal and occipital lobes, in agreement with previous histopathological data. Further metabolic deficits were defined in all regions at earlier time points, including the cerebellum, where very little neurological degeneration has been reported. Biochemical abnormalities in the CSF of affected sheep at 18–31 months include relative increases in lactate, acetate, tyrosine, and creatine/creatinine concentrations and decreases in myo‐ and scyllo‐inositol and citrate concentrations. The changes detected in the CSF and brain tissue mirrored those previously apparent in NCL mouse models, suggesting that they are common to all NCLs. However, the changes in glutamate and glutamine concentrations in CSF occurred after clinical disease, indicating that any changes in glutamate/glutamine cycling occur as a consequence of the primary deficits associated with the NCLs. © 2007 Wiley‐Liss, Inc.
Immunohistochemical distribution of glucose‐dependent insulinotropic polypeptide in the adult rat brain
Authors: Nyberg Jenny , Jacobsson Calle , Anderson Michelle F. , Eriksson Peter S. 
Published: May 2007

AbstractWe have previously demonstrated that glucose‐dependent insulinotropic polypeptide (GIP; gastric inhibitory polypeptide) is present in the adult rat hippocampus. This finding leads to the conclusion that all members of the secretin‐glucagon family of gastrointestinal regulatory polypeptides can be found in the brain. To investigate the localization of GIP‐producing cells, we used immunohistochemistry on sections of the adult rat brain. High levels of GIP immunoreactivity were observed in the olfactory bulb, hippocampus, and Purkinje cells in the cerebellum. Moreover, a moderate but distinct GIP immunoreactivity was observed in the cerebral cortex, amygdala, substantia nigra, and lateral septal nucleus as well as in several nuclei in the thalamus, hypothalamus, and brainstem. GIP immunoreactivity was frequently found to colocalize with the neuronal marker NeuN but never with the glial marker glial fibrillary acidic protein. Thus, GIP appears to be mainly neuronal to its distribution. This widespread distribution of GIP‐immunoreactive cells suggests the involvement of GIP in various neuronal functions and suggests that GIP may act as a neurotransmitter or neuromodulator. This is the first characterization of the anatomical distribution of GIP‐immunoreactive cells in the rat brain providing an anatomical framework for future investigations regarding the functions of GIP in the central nervous system. © 2007 Wiley‐Liss, Inc.
Amyloid beta protein‐related death‐inducing protein induces G2/M arrest: Implications for neurodegeneration in Alzheimer's disease
Authors: Lakshmana Madepalli K. , Hara Hideo , Tabira Takeshi 
Published: May 2007

AbstractAmyloid beta protein (Aβ)‐related death‐inducing protein (AB‐DIP) is a novel Aβ binding protein expressed ubiquitously. Here we demonstrate that overexpression of AB‐DIP in SH‐SY5Y neuroblastoma cells causes G2/M arrest. By deletion mutant analysis, we have identified the minimal region within AB‐DIP required for G2/M arrest. We have also shown that microtubule‐interfering agents (MIAs) such as nocodazole, vinblastine, paclitaxel, and vincristine, known to arrest cells at G2/M, also phosphorylate AB‐DIP. However, etoposide, which causes genotoxic stress; tunicamycin, an ER stress inducer; and rotenone, which causes mitochondrial damage, fail to phosphorylate AB‐DIP, implying that phosphorylation of AB‐DIP is specific to microtubule‐disruption‐induced G2/M arrest. By using different classes of kinase inhibitors, we also demonstrate that a putative tyrosine kinase phosphorylates AB‐DIP. Mono‐ or multisite mutations of tyrosine or serine/threonine residues confirmed that mutation of tyrosine residues but not serine/threonine residues greatly reduces nocodazole‐induced phosphorylation of AB‐DIP. Furthermore, phosphorylation of AB‐DIP can be induced in MCF‐7 cells that lack functional p53, suggesting that AB‐DIP phosphorylation is independent of p53. Mounting experimental evidence continues to support the role of cell cycle abnormalities in the pathogenesis of Alzheimer's disease, and our results suggest that AB‐DIP might provide a mechanistic link between microtubule disruption, mitotic abnormalities, neuronal dysfunction, and death. Therefore, interfering with AB‐DIP may have therapeutic applications in conditions such as Alzheimer's disease, in which microtubule disruption and mitotic abnormalities have been suggested to play a pathological role. © 2007 Wiley‐Liss, Inc.
Chemokine ligand 2 (CCL2) induces migration and differentiation of subventricular zone cells after stroke
Authors: Liu Xian Shuang , Zhang Zheng Gang , Zhang Rui Lan , Gregg Sara R. , Wang Lei , Yier Toh , Chopp Michael 
Published: May 2007

AbstractIschemic stroke stimulates neurogenesis in the adult rodent brain. The molecules that mediate stroke‐induced neurogenesis have not been fully investigated. Using a microarray containing 113 known genes associated with angiogenesis, we analyzed transcriptional profiles in subventricular zone (SVZ) tissue and in cultured neural progenitor cells isolated from the SVZ of adult mice subjected to middle cerebral artery occlusion (MCAo). Among the genes most robustly up‐regulated by MCAo were chemokine ligand 2 (CCL2) and chemokine ligand 10 (CXCL10). Consistent with the mRNA data, immunofluorescent staining revealed that MCAo substantially increased the number of CCL2‐positive cells in the ipsilateral SVZ and that CCL2‐positive cells were positive for both glial fibrillary acidic protein (GFAP) and nestin. In vitro studies showed that incubation of neural progenitor cells with recombinant human CCL2 substantially increased the number of Tuj1‐positive cells dose dependently compared with the number in the control group, indicating that CCL2 promotes neuronal differentiation. Blockage of CCL2 with a neutralized antibody against CCL2 abolished the effects of CCL2 on neural progenitor cell migration and differentiation. Treatment of neural progenitor cells with CCL2 did not alter the number of BrdU cells and the number of apoptotic cells compared with those in the control group, suggesting that CCL2 does not affect neural progenitor cell proliferation and cell survival. These data demonstrate that in addition to its role in cell motility, CCL2 plays an important role in neuronal differentiation. © 2007 Wiley‐Liss, Inc.
Effects of OP‐1 and PTH in a new experimental model for the study of metaphyseal bone healing
Authors: Tsiridis Eleftherios , Morgan Elise F. , Bancroft Jared M. , Song Mike , Kain Michael , Gerstenfeld Louis , Einhorn Thomas A. , Bouxsein Mary L. , Tornetta Paul 
Published: May 2007

AbstractThe purpose of this study was to establish a reliable model of metaphyseal bone healing and to use this model to investigate the effect of recombinant human osteogenic protein 1 (rhOP‐1; BMP‐7) and parathyroid hormone fragment (PTH 1–34) on healing. A wedge‐shaped osteotomy was created in the distal tibia of 16‐week‐old female New Zealand White rabbits (n = 20) and was bridged with a custom‐made external fixator. Five experimental groups of four animals each were investigated. In groups 1–4 the osteotomy gap was filled with tricalcium phosphate (TCP), and the gap was left unfilled in group 5 (“normal healing”). In group 1, 200 µg OP‐1 was mixed in with the TCP. Groups 2 and 3 received daily subcutaneous injections of 10 and 40 µg/kg PTH, respectively, beginning on postoperative day 1. Radiographs were taken weekly. Following sacrifice on postoperative day 28, peripheral quantitative computed tomography (pQCT), histology, and mechanical testing (axial compression and torsion) were performed. Only one animal failed to complete the full 4‐week time course, and no infections were encountered. Bone healing occurred in all animals. OP‐1 stimulated bone formation locally, while the lower dose of PTH enhanced bone formation systemically (p < 0.05). Tibiae treated with OP‐1 exhibited higher torsional strength (p = 0.04) than those in the normal healing group. These results indicate that a reliable and reproducible surgical model of metaphyseal healing has been established. In addition, differences in systemic versus local effects of PTH and OP‐1 in accelerating metaphyseal fracture healing were found. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25:1193–1203, 2007
Prediction and understanding system peaks in capillary zone electrophoresis
Authors: Gaš Bohuslav , Hruška Vlastimil , Dittmann Monika , Bek Fritz , Witt Klaus 
Published: May 2007

AbstractIntroduction of a sample into the separation column (microchip channel) in capillary zone electrophoresis (microchip electrophoresis) will cause a disturbance in the originally uniform composition of the background electrolyte. The disturbance, a system zone, can move in some electrolyte systems along the separation channel and, on reaching the position of the detector, cause a system peak. As shown by the linear theory of electromigration based on linearized continuity equations formulated in matrix form, the mobility of the system zone – the system eigenmobility – can be obtained as the eigenvalue of the matrix. Progress in the theory of electromigration allows us to predict the existence and mobilities of the system zones, even in very complex electrolyte systems consisting of several multivalent weak electrolytes, or in micellar systems (systems with SDS micelles) used for protein sizing in microchips. The theory is implemented in PeakMaster software, which is available as freeware (www.natur.cuni.cz/gas). The linearized theory also predicts background electrolytes having no stationary injection zone (water zone, water gap, water dip, EO zone) or unstable electrolyte systems exhibiting oscillations and creating periodic structures. The oscillating systems have complex system eigenmobilities (eigenvalues of the matrix are complex). This paper reviews the theoretical background of the system peaks (system eigenpeaks) and gives practical hints for their prediction and for preparing background electrolytes not perturbed by the occurrence of system peaks and by excessive peak broadening.
Surface modified polypropylene pipette tips packed with a monolithic plug of adsorbent for high‐throughput sample preparation
Authors: Altun Zeki , Hjelmström Anette , Abdel‐Rehim Mohamed , Blomberg Lars G. 
Published: May 2007

AbstractUV‐initiated poly(butyl methacrylate‐ethylene glycol dimethacrylate) porous polymer monoliths were prepared in situ in polypropylene‐based pipette tips for high‐throughput sample preparation. Prior to the in situ polymerization, the surface of the PP tips was modified. In this work, two different surface modification approaches were tested for this purpose. First the photoinitiator benzophenone was used to generate radicals at the surface of PP by hydrogen abstraction. In the second modification approach, a thin layer of a polymer was directly grafted to the surface. The effect of surface modification was measured by contact angle measurements of a drop of water at the surface. As a result of the surface modification, scan electron microscopy images indicate a covalent attachment of the monolith to the wall of the pipette tip. Pipette tips modified with 5% BP in methanol and packed with a plug of monolith were further evaluated for high‐throughput sample preparation. Using a liquid handling system, the extraction performance of packed pipette tips was tested for the analysis of ropivacaine in plasma samples. The recovery and reproducibility results were in accordance with internationally accepted criteria for qualitative and quantitative analysis of the test substance, ropivacaine.
Functionalized HMS mesoporous silica as solid phase extractant for Pb(II) prior to its determination by flame atomic absorption spectrometry
Authors: Pérez‐Quintanilla Damián , Sánchez Alfredo , del Hierro Isabel , Fajardo Mariano , Sierra Isabel 
Published: May 2007

AbstractIn this work, a mesoporous silica has been chemically modified with 5‐mercapto‐1‐methyl‐1‐H‐tetrazol using the homogeneous route (MTTZ‐HMS). This synthetic route involved the reaction of 5‐mercapto‐1‐methyl‐1‐H‐tetrazol with 3‐chloropropyltriethoxysilane, prior to immobilization on the support. The resulting material has been characterized and employed as solid phase extractant for Pb(II). The effect of several variables (stirring time, pH, temperature, metal concentration, presence of other metals) has been studied using batch and column techniques. In batch experiments, 15 min stirring time, 55°C and pH 8 were the optimal conditions for Pb(II) adsorption. In column experiments, sorption was quantitative for 1000 mL of 2.41×10–4 mM of Pb(II) solution and adsorbed ions were eluted out by 5 mL of 1 M HCl (preconcentration factor of 200). Spiked tap water was used for the preconcentration and determination of Pb(II) by flame atomic absorption spectrometry, and a 100% recovery was obtained. The LOD and LOQ values of the proposed method were found to be 3.52×10–3 and 4.20×10–3 mM, respectively. The RSD for three preconcentration experiments was found to be ⪇2%. The linear working range for measurements was between 2×10–3 and 0.14 mM (y = 0.0136x + 0.0007, R2 = 0.9999).
Acceleration of absolute negative mobility
Authors: Regtmeier Jan , Grauwin Sebastian , Eichhorn Ralf , Reimann Peter , Anselmetti Dario , Ros Alexandra 
Published: May 2007

AbstractRecently, the counter intuitive migration phenomenon of absolute negative mobility (ANM) has been demonstrated to occur for colloidal particles in a suitably arranged post array within a microfluidic device [1]. This effect is based on the interplay of Brownian motion, nonlinear dynamics induced through microstructuring, and nonequilibrium driving, and results in a particle movement opposite to an applied static force. Simultaneously, the migration of a different particle species along the direction of the static force is possible [19], thus providing a new tool for particle sorting in microfluidic device format. The so far demonstrated maximum velocities for micrometer‐sized spheres are slow, i. e., in the order of 10 nm per second. Here, we investigate numerically, how maximum ANM velocities can be significantly accelerated by a careful adjustment of the post size and shape. Based on this numerical analysis, a post design is developed and tested in a microfluidic device made of PDMS. The experiment reveals an order of magnitude increase in velocity.