julilili42/papers huggingface dataset:
Regulation of the glutamate transporter EAAT1 by the ubiquitin ligase Nedd4‐2 and the serum and glucocorticoid‐inducible kinase isoforms SGK1/3 and protein kinase B
2003-08-11

Abstract Surface expression of the glial glutamate transporter EAAT1 is stimulated by insulin‐like growth factor 1 through activation of phosphatidylinositol‐3‐kinase. Downstream targets include serum and glucocorticoid‐sensitive kinase isoforms SGK1, SGK2 and SGK3, and protein kinase B. SGK1 regulates Nedd4‐2, a ubiquitin ligase that prepares cell membrane proteins for degradation. To test whether Nedd4‐2, SGK1, SGK3 and protein kinase B regulate EAAT1, cRNA encoding EAAT1 was injected into Xenopus oocytes with or without additional injection of wild‐type Nedd4‐2, constitutively active S422D SGK1, inactive K127N SGK1, wild‐type SGK3 and/or constitutively active T308D,S473D PKB. Glutamate induces a current in Xenopus oocytes expressing EAAT1, but not in water‐injected oocytes, which is decreased by co‐expression of Nedd4‐2, an effect reversed by additional co‐expression of S422D SGK1, SGK3 and T308D,S473D PKB, but not K127N SGK1. Site‐directed mutagenesis of the SGK1 phosphorylation sites in the Nedd4‐2 protein ( S382A,S468A Nedd4‐2) and in the EAAT1 protein ( T482A EAAT1, T482D EAAT1) significantly blunts the effect of S422D SGK1. Moreover, the current is significantly larger in T482D EAAT1‐ than in T482A EAAT1‐expressing oocytes, indicating that a negative charge mimicking phosphorylation at T482 increases transport. The experiments reveal a powerful novel mechanism that regulates the activity of EAAT1. This mechanism might participate in the regulation of neuronal excitability and glutamate transport in other tissues.
Tumour necrosis factor and nuclear factor B inhibit transcription of human TFF3 encoding a gastrointestinal healing peptide
2003-08-11

Downregulation of intestinal trefoil factor TFF3 is caused by repression of transcription through TNF-alpha and NFkappaB activation in vitro. In IBD, perpetual activation of NFkappaB activity may contribute to ulceration and decreased wound healing through reduced TFF3.
GaBoDS: The Garching-Bonn Deep Survey
2003-08-11

The Garching-Bonn Deep Survey (GaBoDS) is a virtual 12 square degree cosmic shear and cluster lensing survey, conducted with the WFI@2.2m MPG/ESO telescope at La Silla. It consists of shallow, medium and deep random fields taken in R-band in subarcsecond seeing conditions at high galactic latitude. A substantial amount of the data was taken from the ESO archive, by means of a dedicated ASTROVIRTEL program. In the present work we describe the main characteristics and scientific goals of GaBoDS. Our strategy for mining the ESO data archive is introduced, and we comment on the Wide Field Imager data reduction as well. In the second half of the paper we report on clusters of galaxies found in the background of NGC 300, a random archival field. We use weak gravitational lensing and the red cluster sequence method for the selection of these objects. Two of the clusters found were previously known and already confirmed by spectroscopy. Based on the available data we show that there is significant evidence for substructure in one of the clusters, and an increasing fraction of blue galaxies towards larger cluster radii. Two other mass peaks detected by our weak lensing technique coincide with red clumps of galaxies. We estimate their redshifts and masses.
The near-synchronous polar V1432 Aql (RX J1940.1–1025): Accretion geometry and synchronization time scale
2003-08-11

The magnetic Cataclysmic Variable (mCV) V1432 Aql (RX J1940.1–1025) belongs to the four-member subclass of near-synchronous polars with a slight non-synchronism (&lt;2%) between the spin period of the white dwarf and the binary period. In these systems the accretion geometry changes periodically with phase of the beat cycle. We present the application of a dipole accretion model for near-synchronous systems developed by Geckeler &amp; Staubert (1997a) to extended optical and X-ray data. We detect a significant secular change of the white dwarf spin period in V1432 Aql of dPspin/dt = −5.4+3.7 −3.2 × 10−9 s/s from the optical data set alone. This corresponds to a synchronization time scale τsγn꜀ = 199+441−75 yr, comparable to the time scale of 170 yr for V1500 Cyg. The synchronization time scale in V1432 Aql is in excellent agreement with the theoretical prediction from the dominating magnetic torque in near-synchronous systems. We also present period analyses of optical CCD photometry and RXTE X-ray data, which argue against the existence of a 4000 s period and an interpretation of V1432 Aql as an intermediate polar. The dipole accretion model also allows us to constrain the relevant parameters of the accretion geometry in this system: the optical data allow an estimate of the dimensionless parameter (R't0/Rvvə)1/2 sin β = 3.6+2.7−1.1, with a lower limit for the threading radius of R0 t0 &gt; 10 Rwd (68% confidence).
Perfluorinated phthalocyanines for optical limiting: Evidence for the direct correlation between substituent electron withdrawing character and the nonlinear optical effect
2003-08-14

The optical limiting performance exhibited by phthalocyanines substituted with electron withdrawing atoms such as F, results considerably enhanced with respect to the optical limiting effect produced by unsubstituted or differently substituted phthalocyanines. This enhancement is verified by comparing under analogous conditions the nonlinear optical transmission of hexadecafluorophthalocyaninato complexes containing TiIV, VIV, ZrIII, and InIII as coordination central atoms, and tetra- or octaalkylsubstituted phthalocyaninato complexes with the same central atoms by means of the Z-scan technique. The remarkable variations of the nonlinear transmittance of perfluorinated phthalocyanines in solution indicates the strong influence that electron-withdrawing groups exhibit upon the variations of the transition dipole moments involved in the electronic transition, which effectively limits the intense radiation.
Cathepsin V is involved in the degradation of invariant chain in human thymus and is overexpressed in myasthenia gravis
2003-08-15

Stepwise degradation of the invariant chain (Ii) is required for the binding of antigenic peptides to MHC class II molecules. Cathepsin (Cat) L in the murine thymus and Cat S in peripheral APCs have both been implicated in the last step of Ii degradation that gives rise to the class II-associated invariant chain peptides (CLIP). Cat V has been recently described as highly homologous to Cat L and exclusively expressed in human thymus and testis, but with no mouse orthologue. We report that Cat V is the dominant cysteine protease in cortical human thymic epithelial cells, while Cat L and Cat S seem to be restricted to dendritic and macrophage-like cells. Active Cat V in thymic lysosomal preparations was demonstrated by active-site labeling. Recombinant Cat V was capable of converting Ii into CLIP efficiently, suggesting that Cat V is the protease that controls the generation of alphabeta-CLIP complexes in the human thymus, in analogy to Cat L in mouse. Comparison of Cat V expression between thymi from patients with myasthenia gravis and healthy controls revealed a significantly higher expression level in the pathological samples, suggesting a potential involvement of this protease in the immunopathogenesis of myasthenia gravis, an autoimmune disease almost invariably associated with thymic pathology.
Human muscle cells express a B7‐related molecule, B7‐H1, with strong negative immune regulatory potential: a novel mechanism of counterbalancing the immune attack in idiopathic inflammatory myopathies
2003-08-15

B7‐H1 is a novel B7 family protein attributed to costimulatory and immune regulatory functions. Here we report that human myoblasts cultured from control subjects and patients with inflammatory myopathies as well as TE671 muscle rhabdomyosarcoma cells express high levels of B7‐H1 after stimulation with the inflammatory cytokine IFN‐γ. Coculture experiments of MHC class I/II‐positive myoblasts with CD4 and CD8 T cells in the presence of antigen demonstrated the functional consequences of muscle‐related B7‐H1 expression: production of inflammatory cytokines, IFN‐γ and IL‐2, by CD4 as well CD8 T cells was markedly enhanced in the presence of a neutralizing anti‐B7‐H1 antibody. This observation was paralleled by an augmented expression of the T cell activation markers CD25, ICOS, and CD69, thus showing B7‐H1‐mediated inhibition of T cell activation. Further, we investigated 23 muscle biopsy specimens from patients with polymyositis (PM), inclusion body myositis (IBM), dermatomyositis (DM), and nonmyopathic controls for B7‐H1 expression by immunohistochemistry: B7‐H1 was expressed in PM, IBM, and DM specimens but not in noninflammatory and nonmyopathic controls. Staining was predominantly localized to areas of strong inflammation and to muscle cells as well as mononuclear cells. These data highlight the immune regulatory properties of muscle cells and suggest that B7‐H1 expression represents an inhibitory mechanism induced upon inflammatory stimuli and aimed at protecting muscle fibers from immune aggression.
Characterization of the carbohydrate moieties of the functional unit RvH1-a of Rapana venosa haemocyanin using HPLC/electrospray ionization MS and glycosidase digestion
2003-08-15

The primary structures of two biantennary N-glycans of the glycoprotein Rapana venosa (marine snail) haemocyanin were determined. Two different structural subunits have been found in R. venosa haemocyanin: RvH1 and RvH2. The carbohydrate content of the N-terminal functional unit RvH1-a of RvH1 was studied and compared with the N-terminal functional unit RvH2-a of RvH2. Oligosaccharide fragments were released from the glycoprotein by Smith degradation of a haemocyanin pronase digest and separated on a Superdex 300 column. The glycopeptide fragments, giving a positive reaction for the orcinol/H2SO4 method, were separated by HPLC. In order to determine the linked sugar chains to the hinge glycopeptides isolated from the functional unit RvH1-a, several techniques were applied, including capillary electrophoresis, matrix-assisted laser desorption ionization-MS and electrospray ionization-MS in combination with glycosidase digestion. On the basis of these results and amino acid sequence analysis, we concluded that the functional unit RvH1-a contains 7% oligosaccharides N-glycosidically attached to Asn262 and Asn401, and the following structures were suggested:
Intracellular visualization of prostate cancer using magnetic resonance imaging.
2003-08-15

The term "molecular imaging" can be broadly defined as the in vivo characterization and measurement of biological processes at the cellular and molecular level. Is a gene expression magnetic resonance imaging (MRI) possible? Therefore, we have developed a novel intravital and intracellular MRI contrast agent composed of a gadolinium complex, an oligonucleotide sequence [peptide nucleic acid (PNA)], and a transmembrane carrier peptide that is composed of a peptide sequence similar to that of the homeodomain of the Antennapedia protein. The goal of our study was to determine whether this contrast agent could be accumulated in tumor cells in vitro (HeLa cells) and in vivo (Dunning R3327 AT1 rat prostate adenocarcinoma) and whether the specificity of the PNA for the up-regulated c-myc mRNA in the cell's cytoplasm would have an effect on contrast agent retention in the tumor cells. Using the c-myc-specific and a c-myc-nonspecific control PNA, an increase in signal intensity in the tumor cells was observed after 10 min in vitro and in vivo (maximum was reached in HeLa cells in vitro in 60 min, in Dunning R3327 AT1 rat prostate adenocarcinoma cells in vivo in 30 min). This increase of signal intensity could be maintained in vitro in HeLa cells for only 4 h and in Dunning R3327 AT1 rat prostate adenocarcinoma cells in vivo at least for 5 h by using the c-myc mRNA-specific PNA as a "retention" agent.
Expression of her-2/neu on acute lymphoblastic leukemias: implications for the development of immunotherapeutic approaches.
2003-08-15

Her-2/neu is a tumor-associated antigen that is expressed on several adenocarcinomas and correlates with poor prognosis. In a previous study (H. J. Bühring et al., Blood, 86: 1916-1923, 1995), it has been demonstrated that Her-2/neu expression can be detected on blast cells from patients with hematological malignancies including acute lymphoblastic leukemia (ALL). Here, we show that Her-2/neu-specific CTLs induced in vitro using peptide-pulsed dendritic cells efficiently lyse primary ALL blasts constitutively expressing both Her-2/neu and human leukocyte antigen A2 in an antigen-specific and MHC-restricted manner. Furthermore, we analyzed the feasibility of this approach in an autologous setting and induced Her-2/neu-specific CTLs using dendritic cells generated from peripheral blood mononuclear cells from an ALL patient that were pulsed with peptides or transfected with in vitro-transcribed Her-2/neu mRNA. Our data demonstrate that Her-2/neu could be used as a potential target for the application of Her-2/neu-directed treatment strategies in ALL including vaccination approaches.
Adenoviral Natural Born Killer Gene Therapy for Malignant Glioma
2003-08-16

Glioblastoma is a lethal neoplasm resistant to conventional radiotherapy and chemotherapy. Natural born killer (NBK), also known as Bcl-2-interacting killer (BIK), is a death-promoting Bcl-2 family protein sharing with Bcl-2 only the Bcl homology 3 (BH3) domain. We here report that an adenoviral vector encoding NBK (Ad-NBK) uniformly induces cell death in 12 human malignant glioma cell lines. Ad-NBK-induced cell death involves neither quantitative mitochondrial cytochrome c release nor caspase 8, 9, 7, or 3 processing and is unaffected by the viral caspase inhibitor, cytokine response modifier A (CRM-A), or selective caspase 8 or 9 inhibitors. In contrast, Ad-NBK-induced cell death is inhibited by the broad-range caspase inhibitor, zVAD-fmk, or by adenoviral gene transfer of the X-linked inhibitor of apoptosis protein (XIAP). Further, Ad-NBK-induced cell death is inhibited by Bcl-2 or Bcl-xL gene transfer. Interestingly, Bcl-2- and Bcl-xL-transfected glioma cells, which are partially protected from Ad-NBK-induced cell death, accumulate much higher levels of NBK than are ever observed in control-infected cells. This indicates that complex formation with Bcl-2 or Bcl-xL sequesters NBK in an inactive form and that free NBK, rather than an NBK-mediated depletion of free antiapoptotic Bcl-2 family proteins, is the proximate mediator of Ad-NBK-induced cell death. Conversely, proteasome inhibition-mediated accumulation of NBK strongly enhances Ad-NBK-induced cell death. Finally, Ad-NBK-infected LN-229 glioma cells are not tumorigenic in nude mice. Thus Ad-NBK triggers an XIAP- and zVAD-fmk-sensitive cell death pathway in glioma cells with potential therapeutic value, provided that NBK expression can be selectively targeted to cancer cells.
Lack of Bdnf and TrkB signalling in the postnatal cochlea leads to a spatial reshaping of innervation along the tonotopic axis and hearing loss
2003-08-18

Members of the neurotrophin gene family and their high-affinity Trk receptors control innervation of the cochlea during embryonic development. Lack of neurotrophin signalling in the cochlea has been well documented for early postnatal animals, resulting in a loss of cochlear sensory neurones and a region-specific reduction of target innervation along the tonotopic axis. However, how reduced neurotrophin signalling affects the innervation of the mature cochlea is currently unknown. Here, we have analysed the consequences of a lack of the TrkB receptor and its ligand, the neurotrophin brain-derived neurotrophic factor (Bdnf), in the late postnatal or adult cochlea using mouse mutants. During early postnatal development, mutant animals show a lack of afferent innervation of outer hair cells in the apical part of the cochlea,whereas nerve fibres in the basal part are maintained. Strikingly, this phenotype is reversed during subsequent maturation of the cochlea, which results in a normal pattern of outer hair cell innervation in the apex and loss of nerve fibres at the base in adult mutants. Measurements of auditory brain stem responses of these mice revealed a significant hearing loss. The observed innervation patterns correlate with opposing gradients of Bdnf and Nt3 expression in cochlear neurones along the tonotopic axis. Thus, the reshaping of innervation may be controlled by autocrine signalling between neurotrophins and their receptors in cochlear neurones. Our results indicate a substantial potential for re-innervation processes in the mature cochlea,which may also be of relevance for treatment of hearing loss in humans.
Genotyping of GB virus C by restriction pattern analysis of the 5′ untranslated region
2003-08-18

Abstract GB virus C (GBV‐C) is a virus that has been proposed as a member of the Flaviviridae family, distantly related to hepatitis C virus (HCV). The virus is able to infect humans parenterally and perinatally, although its true pathogenicity remains unknown. The 5′ terminal region of GBV‐C is the most highly conserved region of the virus genome. Comparison of 5′ untranslated region (5′ UTR) sequences from GBV‐C infected individuals shows that variation is limited to particular sites that are often covariant and associated with different virus genotypes. Extensive sequence analysis of the GBV‐C genome provides evidence for the existence of at least five major genotypes, some of which can be further divided into subtypes. For genotyping by restriction fragment length polymorphism (RFLP), it is essential to identify genomic positions that not only reflect genotype differences, but that also harbor restriction sites that allow recognition of these differences. Restriction site analysis of type‐specific sequence motifs predicted that endonucleases Bsm FI, Hae II, Hin fI, and Scr FI could be used for the identification all known genotypes (types 1–5) with 99.6% accuracy. The method was applied to serum samples from 46 chronic GBV‐C carriers of heterogeneous geographical and ethnic origin, comparing observed cleavage patterns of GBV‐C variants amplified by reverse transcriptase‐polymerase chain reaction (RT‐PCR) of the 5′ UTR with the RFLP predicted from sequences deposited in GenBank database. cDNA sequencing and subsequent alignment of the 46 GBV‐C isolates confirmed RFLP profiles predicted theoretically. The observed geographical distribution of genotypes is also in agreement with previous reports. This method may be useful for rapid and reliable characterization of GBV‐C isolates when either epidemiological or transmission studies are carried out. J. Med. Virol. 71:226–232, 2003. © 2003 Wiley‐Liss, Inc.
Is politician A or politician B more persuasive? recipients' source preference and the direction of biased message processing
2003-08-19

Abstract Participants' preference for one of two politicians running for the post of Chancellor in Germany was measured. Under conditions conducive to effortful processing, participants were then presented with a persuasive message ascribed to one of these two sources. The message was either unambiguous strong, unambiguous weak, or ambiguous. Different from previous research on the role of message ambiguity for attitude change, the ambiguous message consisted of arguments rated as moderately convincing in a pretest rather than of a mixture of strong and weak arguments. The results were in line with predictions derived from the heuristic‐systematic model (HSM). Indicating unbiased systematic processing, an unambiguous strong message led to more agreement than an unambiguous weak message. In the case of an ambiguous message, in line with the HSM's bias hypothesis, more agreement was found among participants preferring the source politician as compared to participants preferring the other politician. Copyright © 2003 John Wiley &amp; Sons, Ltd.
Determination of Binding Constants on Microarrays with Confocal Fluorescence Detection
2003-08-19

Confocal laser scanning microscopy was employed for the determination of binding constants of receptor-ligand interactions in a microarray format. Protocols for a localized immobilization of amine containing substances on glass via GOPTS (3-glycidyloxypropyl)trimethoxysilane) were optimized with respect to the detection of ligand binding by fluorescence. Compatibility with miniaturization by nanopipetting devices was ensured during all steps. The interaction of the tripeptide L-Lys-D-Ala-D-Ala with vancomycin immobilized on glass served as a model. To minimize consumption of ligand, binding constants were determined by stepwise titration of binding sites. The binding constant of the unlabeled ligand was determined by competitive titration with a fluorescently labeled analogue. The determined binding constants agreed well with those determined by other techniques, previously. Labeled ligand bound stronger than the unlabeled one. This difference was dye-dependent. Still, binding was specific for the tripeptide moiety confirming that ligand and fluorescent analogue competed for the same binding sites these results validate the determination of binding constants by competitive titration. The protocols established for confocal fluorescence detection are applicable to axially resolved detection modalities and screening for unlabeled ligands by competitive titration in general.
Quorum‐Sensing Control of Biofilm Factors inStaphylococcus epidermidis
2003-08-22

Staphylococcus epidermidis is the most frequent cause of nosocomial sepsis and catheter-related infections, in which biofilm formation is considered to be the main virulence mechanism. Quorum-sensing systems have been recognized as important regulators of virulence and biofilm formation in many bacteria. There is a single quorum-sensing system in S. epidermidis encoded by the agr operon. To investigate quorum-sensing control of biofilm formation, we constructed an agr deletion mutant, assayed for the different stages of biofilm formation, and determined agr-dependent regulation of biofilm factors. The agr mutant showed increased biofilm formation, primary attachment, and expression of the autolysin AtlE, but lacked delta-toxin production. However, the level of polysaccharide intercellular adhesin expression was equivalent to the isogenic wild-type strain. In contrast to AtlE, which is known to influence primary attachment, delta-toxin appeared to exert its effect on attachment to polystyrene during later stages of biofilm formation. Importantly, addition of cross-inhibiting pheromones mimicked an agr mutation and significantly enhanced biofilm formation, which suggests that care should be used when treating S. epidermidis infections with cross-inhibiting peptides. Our data demonstrate the importance of quorum sensing in the establishment of a biofilm in this critical human pathogen.
Structural Evaluation of Systematically Enumerated Hypothetical Uninodal Zeolites
2003-08-22

Along theoretical channels: Although 139 distinct structural types of zeolite are currently known, the search for new structures with improved applications in catalysis and ion exchange is of extreme interest. Recent advances in mathematical tiling theory has given rise to the enumeration of 294 uninodal frameworks with an empirical formula SiO2 (an energetically stable example of which is shown).