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  • Institute of Physics (IOP)  (24)
  • Munksgaard International Publishers  (5)
  • 1
    Electronic Resource
    Electronic Resource
    Copenhagen : Munksgaard International Publishers
    Immunological reviews 181 (2001), S. 0 
    ISSN: 1600-065X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Summary: Natural killer (NK)-cell function is regulated by NK receptors that recognize MHC class I (MHC-I) molecules on target cells. Two structurally distinct families of NK receptors have been identified, the immunoglobulin-like family (killer cell immunoglobulin-like receptors (KIRs), leukocyte immunoglobulin-like receptors (LIRs)) and the C-type lectin-like family (Ly49, CD94/NKG2A, NKG2D, CD69). Recently, the three-dimensional structures of several NK receptors were determined, in free form or bound to MHC-I. These include those of unbound KIRs, NKG2D, CD69, LIR-1 and the CD94 subunit of the CD94/NKG2A heterodimer. Together, these structures define the basic molecular architecture of both the immunoglobulin-like and C-type lectin-like families of NK receptors. In addition, crystal structures have been reported for the complex between Ly49A and H-2Dd, and for KIR2DL2 bound to HLA-Cw3. The complex structures provide a framework for understanding MHC-I recognition by NK receptors from both families and reveal striking differences in the nature of this recognition, despite the receptors’ functional similarity.This research was supported, in part, by National Institutes of Health grants R01 AI47900 and R37 36900 (RAM) and a fellowship from the Cancer Research Institute (MWS). We are grateful to DW Wolan and IA Wilson for providing coordinates of NKG2D prior to publication, and to members of our laboratories for encouragement.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Journal of pineal research 38 (2005), S. 0 
    ISSN: 1600-079X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract:  Pregnane X receptor (PXR) is a member of the nuclear receptor superfamily that regulates target gene transcription in a ligand-dependent manner. Our earlier study indicated that reactive oxygen species contribute to lipopolysaccharide (LPS)-induced down-regulation of PXR and its target gene CYP3A in mouse liver. Melatonin is a powerful endogenous antioxidants. In this study, we investigated the effects of melatonin on LPS-induced down-regulation of PXR and CYP3A in mouse liver. Mice were intraperitoneally administrated different doses of melatonin before and/or after LPS treatment. PXR and CYP3A11 mRNA levels were measured using RT-PCR. Erythromycin N-demethylase (ERND) was used as an indicator of CYP3A catalytic activity. Results indicated that melatonin significantly attenuated LPS-induced down-regulation of PXR and CYP3A11 mRNA levels in a dose-dependent manner. Repeated doses of melatonin (10 mg/kg) treatments also significantly attenuated LPS-induced down-regulation of dexamethasone-inducible CYP3A11 mRNA level and ERND activity in mouse liver. In addition, the present study also shows that melatonin significantly increased hepatic superoxide dismutase, Se-dependent glutathione peroxidase, glutathione reductase and catalase activities and glutathione levels in LPS-treated mice. These findings suggest that melatonin may exert its protective effects on LPS-induced down-regulation of PXR and CYP3A via counteracting LPS-induced oxidative stress in mouse liver.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Journal of pineal research 37 (2004), S. 0 
    ISSN: 1600-079X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract:  We have found recently that melatonin protects SH-SY5Y neuroblastoma cells from calyculin A-induced neurofilament impairment and neurotoxicity. In the present study, we further investigated the in vivo effect of inhibiting melatonin biosynthesis on spatial memory retention and tau phosphorylation in rats and the potential underlying mechanisms by using haloperidol, a specific inhibitor of 5-hydroxyindole-O-methyltransferase, and a key enzyme in melatonin biosynthesis. We have found that injection of haloperidol into the lateral ventricle and into peritoneal cavity compromises spatial memory retention of rats and induces hyperphosphorylation of microtubule-associated protein tau at tau-1 (Ser199/Ser202) and PHF-1 (Ser396/Ser404) epitopes. At mean time, the activity of protein phosphatase-2A (PP-2A), a deficit phosphatase in the Alzheimer's disease brain and superoxide dismutase decreases with an elevated level of malondialdehyde. Supplementation with melatonin by prior injection for 1 wk and reinforcement during the haloperidol administration significantly improves memory retention deficits, arrests tau hyperphosphorylation and oxidative stress, and restores PP-2A activity. These results strongly support the involvement of decreased melatonin in Alzheimer-like spatial memory impairment and tau hyperphosphorylation, and PP-2A may play a role in mediating aberrant melatonin-induced lesions.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Journal of pineal research 37 (2004), S. 0 
    ISSN: 1600-079X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract:  Hyperphosphorylation of microtubule-associated protein tau at specific sites is a recognized pathological process in Alzheimer's disease (AD), and protein kinase A (PKA) is a crucial kinase in AD-like tau hyperphosphorylation. In the present study, isoproterenol (ISO) was injected bilaterally into hippocampus of rat brain; ISO is a specific PKA activator and it induces tau hyperphosphorylation. With this system, melatonin (MT) was shown to protect against ISO-induced tau hyperphosphorylation. We found that hippocampal injection of ISO (0.02 μm) induced PKA overactivation and tau hyperphosphorylation at both paired helical filament (PHF)-1 and tau-1 sites. ISO injection also resulted in activation of superoxide dismutase (SOD) and elevation of malondialdehyde (MDA), parameters suggesting elevated oxidative stress. Preinfusion of MT intraperitoneally partially reversed ISO-induced tau hyperphosphorylation at the PHF-1 epitope (1 and 10 mg/kg continuously for 4 wk or 10 mg/kg for 1, 2 or 3 wk) and tau-1 epitope (10 mg/kg for 2 wk). Furthermore, MT (10 mg/kg for 2 wk) obviously antagonized ISO-induced PKA overactivation, as well as enhanced SOD activity and decreased the level of MDA. It is suggested from these data that ISO may induce abnormal hyperphosphorylation of tau through not only the activation of PKA but also because of the fact that it increases oxidative stress; MT may protect against ISO-induced tau hyperphosphorylation through suppression of both PKA overactivation and oxidative stress.
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Journal of pineal research 36 (2004), S. 0 
    ISSN: 1600-079X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract:  Hyperphosphorylation of cytoskeletal proteins seen in Alzheimer's disease is most probably the result of an imbalanced regulation in protein kinases and protein phosphatases (PP) in the affected neurons. Previous studies have revealed that PP-2A and PP-1 play important roles in the pathogenesis. Employing human neuroblastoma cells, we found that 10 nm calyculin A (CA), a selective inhibitor of PP-2A and PP-1, significantly increased phosphorylation and accumulation of neurofilament (NF) in the cells. Levels of NF-M (middle chain) and NF-L (light chain) mRNA decreased after CA treatment. Additionally, CA led to a decreased cell viability determined by MTT and crystal violet assay. Melatonin efficiently protects the cell from CA-induced alterations in NF hyperphosphorylation and accumulation, suppressed NF gene expression as well as decreased cell viability. It is concluded that inhibition of PP-2A/PP-1 by CA induces abnormalities in NF metabolism and cell survival, and melatonin efficiently arrests the lesions.
    Type of Medium: Electronic Resource
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  • 6
    Publication Date: 2011-08-26
    Description: In this paper, we studied the development of hadronic shower in an electromagnetic calorimeter of Alpha Magnetic Spectrometer II. Two parametrized empirical formulae were proposed to describe the hadronic shower shape in calorimeter. Using 100 GeV proton beam incident on the center of the ECAL, detailed plots of lateral and longitudinal hadronic shower behavior were given and we found the formulae can describe the development of the hadronic shower with the test beam data. The possible application of the parametrized formulae including e ± -π ± discrimination and tau jet reconstruction was discussed.
    Print ISSN: 1674-1137
    Topics: Physics
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  • 7
    Publication Date: 2011-03-12
    Description: In the LHC experiment, the neutral pions produced during jet fragmentation are the background sources for all physics channels with high-energy photons in their final state. In this paper, the application of the three-dimensional parametric formula for electromagnetic (EM) showers, which we developed in the Alpha Magnetic Spectrometer II experiment, is presented to distinguish the unconverted photons from the neutral pions. With the constructed electromagnetic calorimeter (ECAL) in a GEANT4 simulation, the parametric formulae were validated and the unconverted γ/π 0 discrimination was performed with the Toolkit for Multivariate Data Analysis (TMVA) package in ROOT for different transverse energies ranging from 15 GeV to 75 GeV, which is the most sensitive region for light Higgs (with mass ~120 GeV) searches with the channel H → γγ. With this discrimination method and the selected transverse energy region, we can reject π 0 with the efficiency from ~40% (65–75...
    Print ISSN: 1674-1137
    Topics: Physics
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  • 8
    Publication Date: 2012-10-19
    Description: In the LHC experiment, the H → γγ channel provides a clean final state with an effective mass peak that is reconstructed with great precision, despite the small branching ratio. As a consequence, the H → γγ channel is one of the most promising channels for the Higgs discovery in the very low mass region. In order to increase the sensitivity of the Higgs search, background rejection rate is very important, so γ/π 0 discrimination is one of the key points in the analysis. At least 40% of photons will convert with the experience of ATLAS and CMS. We constructed electromagnetic calorimeter (ECAL) in GEANT4 simulation, using 6 variables which have different shapes between converted γ and π 0 , with the TMVA (Toolkit for Multivariate Data Analysis) to do the separation. With this method we can get 30% to 60% π 0 rejection efficiency when keeping 90% converted γ efficiency, in the region of transverse momentum 15 GeV to 75 GeV, not only in MC sumulation but...
    Print ISSN: 1674-1137
    Topics: Physics
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  • 9
    Publication Date: 2012-01-18
    Description: The properties of neutron-rich boron isotopes are studied in the relativistic continuum Hartree-Bogoliubov theory in coordinate space with NL-SH, PK1 and TM2 effective interactions. Pairing corrections are taken into account by a density dependent force of zero range. The binding energies calculated for these nuclei agree with the experimental data quite well. The neutron-rich nucleus 17 B has been predicted to have a two-neutron halo structure in its ground state. The halo structure of 17 B is reproduced in a self-consistent way, and this halo is shown to be formed by the valence neutron level 2 s 1/2 .
    Print ISSN: 1674-1137
    Topics: Physics
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  • 10
    Publication Date: 2014-08-14
    Description: During carbon ion therapy, lots of positron emitters such as 11 C, 15 O, 10 C are generated in irradiated tissues by nuclear reactions, and can be used to track the carbon beam in the tissue by a positron emission tomography (PET) scanner. In this study, an dual-plate in-room PET scanner has been designed and evaluated based on the GATE simulation platform to monitor patient dose in carbon ion therapy. The dual-plate PET is designed to avoid interference with the carbon beamline and with patient positioning. Its performance was compared with that of four-head and full-ring PET scanners. The dual-plate, four-head and full-ring PET scanners consisted of 30, 60, 60 detector modules, respectively, with a 36 cm distance between directly opposite detector modules for dose deposition measurements. Each detector module consisted of a 24×24 array of 2 mm×2 mm×18 mm LYSO pixels coupled to a Hamamatsu H8500 PMT. To estimate the production yield of positron emi...
    Print ISSN: 1674-1137
    Topics: Physics
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