bluuebunny/crossref_metadata_2025_split huggingface dataset:
MAPK pathway activation and the origins of pediatric low‐grade astrocytomas
Authors: Tatevossian Ruth G. , Lawson Andrew R.J. , Forshew Tim , Hindley Guy F.L. , Ellison David W. , Sheer Denise 
Published: November 2009

AbstractLow‐grade astrocytomas (LGAs) are the most common type of brain tumor in children. Until recently, very little was known about the underlying biology and molecular genetics of these tumors. However, within the past year a number of studies have shown that the MAPK pathway is constitutively activated in a high proportion of LGAs. Several genetic aberrations which generate this deregulation of the MAPK pathway have been identified, most notably gene fusions between KIAA1549 and BRAF. In this review we summarize these findings, discuss how these gene fusions may arise and consider possible implications for diagnosis and treatment. J. Cell. Physiol. 222: 509–514, 2010. © 2009 Wiley‐Liss, Inc.
Evaluation of critical size defects of mouse calvarial bone: An organ culture study
Authors: Wu Xiaohong , Downes Sandra , Watts David C. 
Published: November 2009

AbstractMouse calvarial organ culture has been used widely for the study of bone biology. The purpose of this study was to evaluate the healing potential of neonatal mouse parietal defects in different culture media. The critical size defect (CSD) was also investigated. The parietal bones of neonatal mice were used. Full‐thickness, 0.8‐mm circular defects were created through the bones from one litter of mice. The bones were divided into three groups: Dulbecco's Modified Eagle Medium (DMEM) group, DMEM/osteogenic medium (OM) group, and OM group. Cultures were analyzed with microcomputed‐tomography, dissecting‐microscope, phase‐contrast‐microscope, Von Kossa stain, scanning‐electron‐microscopy, and energy‐dispersive‐X‐ray. Continuous bone formation of parietal bones was observed in all groups. Defects in the DMEM/OM group showed the highest healing potential and exhibited woven bone formation. Defects in the OM group showed limited bone healing at the defect edge. Defects in the DMEM group showed fibrous healing. The most effective culture medium (DMEM/OM) was used to determine the CSD of mouse calvaria in a separate experiment. Circular defects (diameters: 0.8, 1.0, and 1.5 mm) were made in the parietal bones from another litter of mice. The bones were analyzed with microcomputed‐tomography, and phase‐contrast‐microscopy. The bone filling percentages of different size defects were statistically significant: 1.5‐mm defects (4.49%), 1.0‐mm defects (47.65%), and 0.8‐mm defects (73.45%). In three culture conditions, DMEM/OM was the most effective approach to repair bone defects. A 1.5 mm in diameter, full‐thickness parietal defect was found to be the CSD under the DMEM/OM culture conditions. Microsc. Res. Tech., 2010. © 2009 Wiley‐Liss, Inc.
Sensilla on the antennae, legs and ovipositor of Spathius agrili Yang (Hymenoptera: Braconidae), a parasitoid of the emerald ash borer Agrilus planipennis Fairmaire (Coleoptera: Buprestidae)
Authors: Wang Xiao‐Yi , Yang Zhong‐Qi , Gould Juli R. 
Published: November 2009

AbstractTo investigate the host‐finding mechanisms of Spathius agrili Yang, a parasitoid of the emerald ash borer, Agrilus planipennis Fairmaire, a highly concealed insect pest of Fraxinus spp. The morphology and ultrastructure of sensilla on the antennae and legs of both sexes and on the ovipositors and ovipositor sheaths of females were observed using SEM. Results showed that abundant sensilla trichodea (ST) are distributed on the antennae of both females and males, with the sharp trichoid with a socket at the base being the most numerous sensillum. There are 6–7 sensilla placodea on each segment of the flagellum, arranged lengthways in parallel rows. There are very few sensilla styloconica on the female antennae. The tibiae have mostly sensilla chaetica, whereas three types of ST and the relatively plentiful sensilla chaetica are present on the tarsi. Besides ST, a mass of sensilla squamiformia and small short spines are distributed on the pulvilli. Basically there are no sensilla on the female ovipositor, only steering mechanisms for drilling bark and a variety of v‐shaped grooves. However, a large numbers of short sensilla chaetica and microtrichia are found on the internal surface of ovipositor sheath. The outer surface of the ovipositor sheath also has ST. In addition, a clear spring‐like extension structure can be observed on the fore parts of ovipositor sheath. These findings suggest that the main function of sensilla on the antennae is olfaction, while the sensilla on legs and ovipositor sheaths are mechanoreceptors and tactile sensors. Microsc. Res. Tech. 2010. © 2009 Wiley‐Liss, Inc.
Aberrant distribution of junctional complex components in retinoic acid receptor alpha‐deficient mice
Authors: Chung Sanny S.W. , Choi Cindy , Wang Xiangyuan , Hallock Loretta , Wolgemuth Debra J. 
Published: November 2009

AbstractRetinoic acid receptor alpha (RARα)‐deficient mice are sterile, with abnormalities in the progression of spermatogenesis and spermiogenesis. In this study, we investigated whether defective retinoid signaling involved at least in part, disrupted cell–cell interactions. Hypertonic fixation approaches revealed defects in the integrity of the Sertoli‐cell barrier in the tubules of RARα‐deficient testes. Dye transfer experiments further revealed that coupling between cells from the basal to adluminal compartments was aberrant. There were also differences in the expression of several known retinoic acid (RA)‐responsive genes encoding structural components of tight junctions and gap junctions. Immunostaining demonstrated a delay in the incorporation of zonula occludens (ZO‐1), a peripheral component protein of tight junctions, into the Sertoli cell tight junctions. Markedly reduced expression of connexin‐40 in mutant pachytene spermatocytes and round spermatids was found by in situ hybridization. An ectopic distribution of vimentin and disrupted cyclic expression of vimentin, which is usually tightly regulated during spermiogenesis, was found in RARα‐deficient testes at all ages examined. Thus, the specific defects in spermiogenesis in RARα‐deficient testes may correlate with a disrupted cyclic expression of RA‐responsive structural components, including vimentin, a downregulation of connexin‐40 in spermatogenic cells, and delayed assembly of ZO‐1 into Sertoli cell tight junctions. Interestingly, bioinformatic analysis revealed that many genes that are components of tight junctions and gap junctions contained potential retinoic acid response element binding sites. Microsc. Res. Tech., 2010. © 2009 Wiley‐Liss, Inc.
Synaptic membrane proteins form stable microdomains in early endosomes
Authors: Geumann Ulf , Schäfer Christina , Riedel Dietmar , Jahn Reinhard , Rizzoli Silvio O. 
Published: November 2009

AbstractIn the plasma membrane, membrane proteins are frequently organized in microdomains that are stabilized both by protein‐protein and protein‐lipid interactions, with the membrane lipid cholesterol being instrumental for microdomain stability. However, it is unclear whether such microdomains persist during endocytotic membrane trafficking. We used stimulated emission‐depletion microscopy to investigate the domain structure of the endosomes. We developed a semiautomatic method for counting the individual domains, an approach that we have validated by immunoelectron microscopy. We found that in endosomes derived from neuroendocrine PC12 cells synaptophysin and several SNARE proteins are organized in microdomains. Cholesterol depletion by methyl‐β‐cyclodextrin disintegrates most of the domains. Interestingly, no change in the frequency of microdomains was observed when endosomes were fused with protein‐free liposomes of similar size (in what constitutes a novel approach in modifying acutely the lipid composition of organelles), regardless of whether the membrane lipid composition of the liposomes was similar or very different from that of the endosomes. Similarly, Rab depletion from the endosome membranes left the domain structure unaffected. Furthermore, labeled exogenous protein, introduced into endosomes by liposome fusion, equilibrated with the corresponding microdomains. We conclude that synaptic membrane proteins are organized in stable but dynamic clusters within endosomes, which are likely to persist during membrane recycling. Microsc. Res. Tech. 2010. © 2009 Wiley‐Liss, Inc.
Optimized time‐gated generalized polarization imaging of Laurdan and di‐4‐ANEPPDHQ for membrane order image contrast enhancement
Authors: Owen Dylan M. , Gaus Katharina 
Published: November 2009

AbstractThe membrane dyes Laurdan and di‐4‐ANEPPDHQ can be used to image membrane order due to a spectral blue‐shift in the fluorescence emission between the liquid‐ordered and liquid‐disordered phases. These images typically take the form of a normalized intensity ratio image known as a generalized polarization (GP) plot. Here, we exploit the known excited state photophysics and time‐resolved data acquisition via time‐correlated single‐photon counting (TCSPC) to demonstrate GP contrast enhancement for these two probes of 7 and 31%, respectively. This improvement in image contrast enhancement will be invaluable when studying the role of lipid rafts in fixed and live cell systems. Microsc. Res. Tech. 2010. © 2009 Wiley‐Liss, Inc.
A metallothionein mimetic peptide protects neurons against kainic acid‐induced excitotoxicity
Authors: Sonn Katrin , Pankratova Stanislava , Korshunova Irina , Zharkovsky Alexander , Bock Elisabeth , Berezin Vladimir , Kiryushko Darya 
Published: November 2009

AbstractMetallothioneins I and II (MTI/II) are metal‐binding proteins overexpressed in response to brain injury. Recently, we have designed a peptide, termed EmtinB, which is modeled after the β‐domain of MT‐II and mimics the biological effects of MTI/II in vitro. Here, we demonstrate the neuroprotective effect of EmtinB in the in vitro and in vivo models of kainic acid (KA)‐induced neurotoxicity. We show that EmtinB passes the blood–brain barrier and is detectable in plasma for up to 24 hr. Treatment with EmtinB significantly attenuates seizures in C57BL/6J mice exposed to moderate (20 mg/kg) and high (30 mg/kg) KA doses and tends to decrease mortality induced by the high KA dose. Histopathological evaluation of hippocampal (CA3 and CA1) and cortical areas of mice treated with 20 mg/kg KA shows that EmtinB treatment reduces KA‐induced neurodegeneration in the CA1 region. These findings establish EmtinB as a promising target for therapeutic development. © 2009 Wiley‐Liss, Inc.
Selection of reference genes for real‐time quantitative reverse transcription‐polymerase chain reaction in hippocampal structure in a murine model of temporal lobe epilepsy with focal seizures
Authors: Pernot Fabien , Dorandeu Frédéric , Beaup Claire , Peinnequin André 
Published: November 2009

AbstractReference genes are often used to normalize expression of data from real‐time quantitative reverse transcription‐polymerase chain reaction (RT‐qPCR), and only a validation of their stability during a given experimental paradigm leads to reliable interpretations. The present study was thus designed to validate potential reference genes in a mouse model of mesiotemporal lobe epilepsy (MTLE) with focal seizures after unilateral intrahippocampal injection of kainate (KA). Ipsilateral and contralateral hippocampi were removed during nonconvulsive status epilepticus (5 hr), epileptogenesis (7 days), and the chronic period of recurrent focal seizures (21 days). Naive animals were equally studied. The stability of eight potential reference genes (hypoxanthine phosphoribosyltransferase, Hprt1; peptidylprolyl isomerase A, Ppia; TATA box binding protein, Tbp; beta‐actin, Actb; acidic ribosomal phosphoprotein P0, Arbp; glyceraldehyde‐3‐phosphate dehydrogenase, Gapdh; ribosomal RNA 18S, 18S rRNA; and glucuronidase beta, Gusb) were determined using geNorm and NormFinder software. The first five (Hprt1, Ppia, Tbp, Actb, and Arbp) were found to be stable across the different phases of the disease and appeared adequate for normalizing RT‐qPCR data in this model. This was in contrast to the other three (18S rRNA, Gapdh, and Gusb), which showed unstable expressions and should be avoided. The analysis of KA‐induced changes in the expression of glial fibrillary acidic protein (Gfap) gene resulted in various relative expressions or even a completely different pattern when unstable reference genes were used. These results highlight the absolute need to validate the reference genes for a correct interpretation of mRNA quantification. © 2009 Wiley‐Liss, Inc.
Calpain activation and Na+/Ca2+exchanger degradation occur downstream of calcium deregulation in hippocampal neurons exposed to excitotoxic glutamate
Authors: Brustovetsky Tatiana , Bolshakov Alexey , Brustovetsky Nickolay 
Published: November 2009

AbstractDelayed calcium deregulation (DCD) plays an essential role in glutamate excitotoxicity, a major detrimental factor in stroke, traumatic brain injury, and various neurodegenerations. In the present study, we examined the role of calpain activation and Na+/Ca2+exchanger (NCX) degradation in DCD and excitotoxic cell death in cultured hippocampal neurons. Exposure of neurons to glutamate caused DCD accompanied by secondary mitochondrial depolarization. Activation of calpain was evidenced by detecting NCX isoform 3 (NCX3) degradation products. Degradation of NCX isoform 1 (NCX1) was below the detection limit of Western blotting. Degradation of NCX3 was detected only after 1 hr of incubation with glutamate, whereas DCD occurred on average within 15 min after glutamate application. Calpeptin, an inhibitor of calpain, significantly attenuated NCX3 degradation but failed to inhibit DCD and excitotoxic neuronal death. Calpain inhibitors I, III, and VI also failed to influence DCD and glutamate‐induced neuronal death. On the other hand, MK801, an inhibitor of the NMDA subtype of glutamate receptors, added shortly after the initial glutamate‐induced jump in cytosolic Ca2+, completely prevented DCD and activation of calpain and strongly protected neurons against excitotoxicity. Taken together, our results suggest that, in glutamate‐treated hippocampal neurons, the initial increase in cytosolic Ca2+that precedes DCD is insufficient for sustained calpain activation, which most likely occurs downstream of DCD. © 2009 Wiley‐Liss, Inc.
Glutamate transporters in the central nervous system of a pond snail
Authors: Hatakeyama Dai , Mita Koichi , Kobayashi Suguru , Sadamoto Hisayo , Fujito Yutaka , Hiripi László , Elekes Károly , Ito Etsuro 
Published: November 2009

AbstractPrevious studies on glutamate (GLU) and its receptors in the pond snail Lymnaea stagnalis have suggested that GLU functions as a neurotransmitter in various behaviors, particularly for generation of feeding rhythm. The uptake mechanism of GLU is not yet known in Lymnaea. In the present study, we characterized the GLU transporters and examined their functions in the feeding circuits of the central nervous system (CNS) in Lymnaea. First, measurement of the accumulation of 3H‐labeled GLU revealed the presence of GLU transport systems in the Lymnaea CNS. The highest accumulation rate was observed in the buccal ganglia, supporting the involvement of GLU transport systems in feeding behavior. Second, we cloned two types of GLU transporters from the Lymnaea CNS, the excitatory amino acid transporter (LymEAAT) and the vesicular GLU transporter (LymVGLUT). When we compared their amino acid sequences with those of mammalian EAATs and VGLUTs, we found that the functional domains of both types are well conserved. Third, in situ hybridization revealed that the mRNAs of LymEAAT and LymVGLUT are localized in large populations of nerve cells, including the major feeding motoneurons in the buccal ganglia. Finally, we inhibited LymEAAT and found that changes in the firing patterns of the feeding motoneurons that have GLUergic input were similar to those obtained following stimulation with GLU. Our results confirmed the presence of GLU uptake systems in the Lymnaea CNS and showed that LymEAAT is required for proper rhythm generation, particularly for generation of the feeding rhythm. © 2009 Wiley‐Liss, Inc.
Conserved cellular function and stress‐mediated regulation among members of the proteolipid protein family
Authors: Fernández María E. , Alfonso Julieta , Brocco Marcela A. , Frasch Alberto C. 
Published: November 2009

AbstractChronic stress causes morphological alterations in the hippocampus of rodents and tree shrews, including atrophy of CA3 dendrites and loss of synapses. The molecular mechanisms underlying these structural changes remain largely unknown. We have previously identified M6a as a stress responsive gene and shown that M6a is involved in filopodium/spine outgrowth and, likely, synapse formation. M6a belongs to the proteolipid protein (PLP) family, all of their members having four transmembrane domains that allow their localization at the plasma membrane. In the present work, we analyzed other members of this family, the closely related M6b as well as PLP and its splice variant DM20. We found that chronic restraint stress in mice reduces M6b and DM20, but not PLP, mRNA levels in the hippocampus. In addition, M6b and DM20, but again not PLP, induce filopodium formation in primary cultures of hippocampal neurons. Several M6b protein isoforms were studied, all of them having similar effects except for the one lacking the transmembrane domains. Our results reveal a conserved cellular function and a stress‐mediated regulation among members of the proteolipid protein family, suggesting an involvement of proteolipid proteins in the stress response. © 2009 Wiley‐Liss, Inc.
Multilevel regression analyses to investigate the relationship between two variables over time: Examining the longitudinal association between intrusion and avoidance
Authors: Suvak Michael K. , Walling Sherry M. , Iverson Katherine M. , Taft Casey T. , Resick Patricia A. 
Published: November 2009

AbstractMultilevel modeling is a powerful and flexible framework for analyzing nested data structures (e.g., repeated measures or longitudinal designs). The authors illustrate a series of multilevel regression procedures that can be used to elucidate the nature of the relationship between two variables across time. The goal is to help trauma researchers become more aware of the utility of multilevel modeling as a tool for increasing the field's understanding of posttraumatic adaptation. These procedures are demonstrated by examining the relationship between two posttraumatic symptoms, intrusion and avoidance, across five assessment points in a sample of rape and robbery survivors (n = 286). Results revealed that changes in intrusion were highly correlated with changes in avoidance over the 18‐month posttrauma period.
Study of the soil–atmosphere moisture exchanges through convective drying tests in non‐isothermal conditions
Authors: Gerard Pierre , Léonard Angélique , Masekanya Jean‐Pierre , Charlier Robert , Collin Frédéric 
Published: November 2009

AbstractThis paper deals with the moisture exchanges occurring between soils and the surrounding atmosphere. Convective drying tests are performed on Awans silts at different drying temperatures and air relative humidities in order to reproduce the natural drying conditions. The experiments improve the understanding of the vapour transfers kinetics between the soil samples and the atmosphere. The experimental results are analysed assuming that the transfers take place in a boundary layer existing at the surface of the porous medium. The influence of the thermal conditions on the evaporation is also taken into account. In our model, coupled vapour and energy exchanges are controlled by mass and heat transfer coefficients characterizing the boundary layer. These coefficients are determined from the drying experiments. The modelling of the drying tests in non‐isothermal conditions is performed in order to validate the formulation of the vapour and heat exchanges. The numerical results present a good agreement with the kinetic of the materials desaturation determined during the tests. The analysis of the moisture transport mechanisms into the sample and at the boundary shows that at the beginning of the test, the drying is first achieved by the transport of moisture in its liquid form and its evaporation at the sample outer boundary in contact with the atmosphere. In a second step, vapour diffusion becomes predominant into the sample and it corresponds to the most important decrease of relative humidity. Copyright © 2009 John Wiley & Sons, Ltd.
A new perspective on strength measures in algebraic multigrid
Authors: Olson Luke N. , Schroder Jacob , Tuminaro Raymond S. 
Published: November 2009

AbstractAlgebraic‐based multilevel solution methods (e.g. classical Ruge–Stüben and smoothed aggregation style algebraic multigrid) attempt to solve or precondition sparse linear systems without knowledge of an underlying geometric grid. The automatic construction of a multigrid hierarchy relies on strength‐of connection information to coarsen the matrix graph and to determine sparsity patterns for the inter‐grid transfer operators. Strength‐of‐connection as a general concept is not well understood and the first task of this paper is therefore on understanding existing strength‐of‐connection measures and their limitations. In particular, we present a framework to interpret and clarify existing measures through differential equations. This framework leads to a new procedure for making pointwise strength‐of‐connection decisions that combines knowledge of local algebraically smooth error and of the local behavior of interpolation. The new procedure effectively addresses a variety of challenges associated with strength‐of‐connection and when incorporated within an algebraic multigrid procedure gives rise to a robust and efficient solver. Copyright © 2009 John Wiley & Sons, Ltd.
An embedded Dirichlet formulation for 3D continua
Authors: Gerstenberger A. , Wall W. A. 
Published: November 2009

AbstractThis paper presents a new approach for imposing Dirichlet conditions weakly on non‐fitting finite element meshes. Such conditions, also called embedded Dirichlet conditions, are typically, but not exclusively, encountered when prescribing Dirichlet conditions in the context of the eXtended finite element method (XFEM). The method's key idea is the use of an additional stress field as the constraining Lagrange multiplier function. The resulting mixed/hybrid formulation is applicable to 1D, 2D and 3D problems. The method does not require stabilization for the Lagrange multiplier unknowns and allows the complete condensation of these unknowns on the element level. Furthermore, only non‐zero diagonal‐terms are present in the tangent stiffness, which allows the straightforward application of state‐of‐the‐art iterative solvers, like algebraic multigrid (AMG) techniques. Within this paper, the method is applied to the linear momentum equation of an elastic continuum and to the transient, incompressible Navier–Stokes equations. Steady and unsteady benchmark computations show excellent agreement with reference values. The general formulation presented in this paper can also be applied to other continuous field problems. Copyright © 2009 John Wiley & Sons, Ltd.