152 research outputs found

    Serial Ultrasonography for Early Detection and Follow-up of Heterotopic Ossification in Stroke

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    Heterotopic ossification (HO) is a common complication in patients with neurologic deficits. Once developed, limited range of motion may occur and interfere with rehabilitation programs. Early diagnosis is crucial but difficult because radiographs may be negative, and similar clinical symptoms could appear in deep venous thrombosis, cellulitis, and osteomyelitis. A three-phase bone scan can detect the disease early, but it has high radiation and low specificity. Magnetic resonance imaging (MRI) may also assist in diagnosis, but is costly and has some contraindications. Ultrasonography has been used in HO detection and is safe, economical, easily accessible, and involves no radiation exposure. However, a few studies have described its use in HO, especially in serial follow-ups. We report a case with HO clinical symptoms, but the MRI results created a necrotizing fasciitis suspicion. Serial ultrasonography images implied the formation of HO rather than necrotizing fasciitis. Ultrasonography images serve as a good initial screening tool for HO and are useful for following up such dynamic disease processes

    Effects of Salvianolic Acid B on Protein Expression in Human Umbilical Vein Endothelial Cells

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    Salvianolic acid B (Sal B), a pure water-soluble compound extracted from Radix Salviae miltiorrhizae, has been reported to possess potential cardioprotective efficacy. To identify proteins or pathways by which Sal B might exert its protective activities on the cardiovascular system, two-dimensional gel electrophoresis-based comparative proteomics was performed, and proteins altered in their expression level after Sal B treatment were identified by MALDI-TOF MS/MS. Human umbilical vein endothelial cells (HUVECs) were incubated at Sal B concentrations that can be reached in human plasma by pharmacological intervention. Results indicated that caldesmon, an actin-stabilizing protein, was downregulated in Sal B-exposed HUVECs. Proteins that showed increased expression levels upon Sal B treatment were vimentin, T-complex protein 1, protein disulfide isomerase, tropomyosin alpha, heat shock protein beta-1, UBX domain-containing protein 1, alpha enolase, and peroxiredoxin-2. Additionally, Sal B leads to increased phosphorylation of nucleophosmin in a dose-dependent manner and promotes proliferation of HUVECs. We found that Sal B exhibited a coordinated regulation of enzymes and proteins involved in cytoskeletal reorganization, oxidative stress, and cell growth. Our investigation would provide understanding to the endothelium protection information of Sal B

    Recombinant Zebrafish ␄-Glutamyl Hydrolase Exhibits Properties and Catalytic Activities Comparable with Those of Mammalian Enzyme

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    ABSTRACT: A cDNA encoding for zebrafish ␄-glutamyl hydrolase (␄GH) was cloned and inserted into a pET43.1a vector via SmaI and EcoRI sites and expressed in Rosetta (DE3) cells as a Nus-His-tag fusion enzyme (NH-z␄GH). After induction with isopropyl thiogalactoside, the enzyme was purified with a Ni-Sepharose column, and approximately 8 mg of pure enzyme was obtained per liter of culture. The primary sequence of the recombinant z␄GH was similar to mammalian ␄GH. Folate is an essential B vitamin and participates in the biosynthesis and metabolism of nucleic acids, proteins, several amino acids, methyl groups, many neurotransmitters, and some vitamins. Mammalian cells are unable to synthesize folates de novo and therefore depend on their food for the supply of folates. Naturally occurring folates are synthesized as poly-␄-glutamate forms (folylpolyglutamate) but are absorbed and transported most efficiently as folylmonoglutamates. The conversion of folylpolyglutamates in dietary food to folylmonoglutamates is catalyzed by carboxypeptidase II (EC 3.4.22.12) in mammals. In a recent study, ␄-glutamyl hydrolase (␄GH, EC 3.4.19.9), a lysosomal cysteine peptidase, was reported to be the enzyme responsible for hydrolyzing dietary folate in rat small intestine Consistent with this notion, the activity of ␄GH to hydrolyze the ␄-glutamyl peptide bonds of folylpolyglutamates has rendered this enzyme a potential target of antifolate chemotherapy and, at the same time, a primary component in regulating the intracellular levels of some antifolate drugs. Antifolate drugs, such as methotrexate, owe much of their effectiveness to being substrates for both folylpoly-␄-glutamate synthetase and ␄GH. Removal of ␄-linked glutamate residues decreases the retention and activity of these drugs. A polymorphism resulting in reduced catalytic activity of ␄GH was observed to be associated with greater accumulation of long-chain methotrexate polyglutamate forms The determination of individual folate derivatives in serum of patients receiving antifolate chemotherapy and in foods is an important current protocol. The first step in these determinations is converting folylpolyglutamates to folylmonoglutamates by ␄GH. Cur- The amino acid numbering used for z␄GH in this study is numbered starting from the first methionine in the full-length peptide with the signal peptide. Article, publication date, and citation information can be found a

    Neutrino Physics with JUNO

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    The Jiangmen Underground Neutrino Observatory (JUNO), a 20 kton multi-purposeunderground liquid scintillator detector, was proposed with the determinationof the neutrino mass hierarchy as a primary physics goal. It is also capable ofobserving neutrinos from terrestrial and extra-terrestrial sources, includingsupernova burst neutrinos, diffuse supernova neutrino background, geoneutrinos,atmospheric neutrinos, solar neutrinos, as well as exotic searches such asnucleon decays, dark matter, sterile neutrinos, etc. We present the physicsmotivations and the anticipated performance of the JUNO detector for variousproposed measurements. By detecting reactor antineutrinos from two power plantsat 53-km distance, JUNO will determine the neutrino mass hierarchy at a 3-4sigma significance with six years of running. The measurement of antineutrinospectrum will also lead to the precise determination of three out of the sixoscillation parameters to an accuracy of better than 1\%. Neutrino burst from atypical core-collapse supernova at 10 kpc would lead to ~5000inverse-beta-decay events and ~2000 all-flavor neutrino-proton elasticscattering events in JUNO. Detection of DSNB would provide valuable informationon the cosmic star-formation rate and the average core-collapsed neutrinoenergy spectrum. Geo-neutrinos can be detected in JUNO with a rate of ~400events per year, significantly improving the statistics of existing geoneutrinosamples. The JUNO detector is sensitive to several exotic searches, e.g. protondecay via the p→K++Μˉp\to K^++\bar\nu decay channel. The JUNO detector will providea unique facility to address many outstanding crucial questions in particle andastrophysics. It holds the great potential for further advancing our quest tounderstanding the fundamental properties of neutrinos, one of the buildingblocks of our Universe

    Potential of Core-Collapse Supernova Neutrino Detection at JUNO

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    JUNO is an underground neutrino observatory under construction in Jiangmen, China. It uses 20kton liquid scintillator as target, which enables it to detect supernova burst neutrinos of a large statistics for the next galactic core-collapse supernova (CCSN) and also pre-supernova neutrinos from the nearby CCSN progenitors. All flavors of supernova burst neutrinos can be detected by JUNO via several interaction channels, including inverse beta decay, elastic scattering on electron and proton, interactions on C12 nuclei, etc. This retains the possibility for JUNO to reconstruct the energy spectra of supernova burst neutrinos of all flavors. The real time monitoring systems based on FPGA and DAQ are under development in JUNO, which allow prompt alert and trigger-less data acquisition of CCSN events. The alert performances of both monitoring systems have been thoroughly studied using simulations. Moreover, once a CCSN is tagged, the system can give fast characterizations, such as directionality and light curve

    Detection of the Diffuse Supernova Neutrino Background with JUNO

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    As an underground multi-purpose neutrino detector with 20 kton liquid scintillator, Jiangmen Underground Neutrino Observatory (JUNO) is competitive with and complementary to the water-Cherenkov detectors on the search for the diffuse supernova neutrino background (DSNB). Typical supernova models predict 2-4 events per year within the optimal observation window in the JUNO detector. The dominant background is from the neutral-current (NC) interaction of atmospheric neutrinos with 12C nuclei, which surpasses the DSNB by more than one order of magnitude. We evaluated the systematic uncertainty of NC background from the spread of a variety of data-driven models and further developed a method to determine NC background within 15\% with {\it{in}} {\it{situ}} measurements after ten years of running. Besides, the NC-like backgrounds can be effectively suppressed by the intrinsic pulse-shape discrimination (PSD) capabilities of liquid scintillators. In this talk, I will present in detail the improvements on NC background uncertainty evaluation, PSD discriminator development, and finally, the potential of DSNB sensitivity in JUNO

    Real-time Monitoring for the Next Core-Collapse Supernova in JUNO

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    Core-collapse supernova (CCSN) is one of the most energetic astrophysical events in the Universe. The early and prompt detection of neutrinos before (pre-SN) and during the SN burst is a unique opportunity to realize the multi-messenger observation of the CCSN events. In this work, we describe the monitoring concept and present the sensitivity of the system to the pre-SN and SN neutrinos at the Jiangmen Underground Neutrino Observatory (JUNO), which is a 20 kton liquid scintillator detector under construction in South China. The real-time monitoring system is designed with both the prompt monitors on the electronic board and online monitors at the data acquisition stage, in order to ensure both the alert speed and alert coverage of progenitor stars. By assuming a false alert rate of 1 per year, this monitoring system can be sensitive to the pre-SN neutrinos up to the distance of about 1.6 (0.9) kpc and SN neutrinos up to about 370 (360) kpc for a progenitor mass of 30M⊙M_{\odot} for the case of normal (inverted) mass ordering. The pointing ability of the CCSN is evaluated by using the accumulated event anisotropy of the inverse beta decay interactions from pre-SN or SN neutrinos, which, along with the early alert, can play important roles for the followup multi-messenger observations of the next Galactic or nearby extragalactic CCSN.Comment: 24 pages, 9 figure

    COMPARISONS OF LIPID DYNAMICS AND PACKING IN FULLY INTERDIGITATED MONOARACHIDOYLPHOSPHATIDYLCHOLINE AND NONINTERDIGITATED DIPALMITOYLPHOSPHATIDYLCHOLINE BILAYERS - CROSS POLARIZATION MAGIC ANGLE SPINNING C-13-NMR STUDIES

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    [[abstract]]13C-NMR spectra have been obtained at 50.3 MHz for monoarachidoylphosphatidylcholine (MAPC) and dipalmitoylphosphatidylcholine (DPPC) dispersions from 25°C to 55°C and for DPPC polycrystals at 25°C using the cross polarization/magic angle spinning technique. Differential scanning calorimetric studies on DPPC and MAPC dispersions show comparable lipid phase transitions with transition temperatures at 41°C and 45°C, respectively, and thus enable the comparison of thermal, structural and dynamic differences between these two systems at corresponding temperatures. Conformational-dependent 13C chemical shift studies on DPPC dispersions demonstrate not only the coexistence of the tilted gel (LÎČâ€Č) and liquid-crystalline (Lα) phases in the rippled gel (PÎČâ€Č) phase, but also the presence of an intermediate third microscopic phase as evidenced by three resolvable peaks for ω-1 methylene carbon signals at the temperature interval between Tp and Tm. By comparing chemical shifts of MAPC in the hydrocarbon chain region with those of DPPC at similar reduced temperatures, it can be concluded that the packings are perturbed markedly in the middle segment of the fatty acyl chain during the lamellar to micellar transition. However, terminal methylene and methyl groups of interdigitated MAPC lamellae were found to be more ordered than those of non-interdigitated DPPC bilayers in the gel state. Interestingly, the terminal methyl groups of MAPC in the micelles remain to be relatively ordered; in fact, they are more ordered than the corresponding acyl chain end of DPPC in the liquid-crystalline state. Analysis of data obtained from rotating frame proton spin-lattice relaxation measurements shows a highly mobile phosphocholine headgroup, a rigid carbonyl group and an ordered hydrocarbon chain for lamellar MAPC in the interdigitated state. Furthermore, results suggest that free rotations of the glycerol C2-C3 bond within MAPC molecules may occur in the interdigitated bilayer, whereas intramolecular exchange between two conformations of the glycerol backbone in DPPC become possible at temperatures close to the pretransition temperature. Without isotope enrichment, we conclude that high-resolution solid-state 13C-NMR is indeed a useful technique which can be employed to study the packing and dynamics of phospholipids.[[fileno]]2050135010028[[department]]生科

    Cobra cardiotoxin and phospholipase A(2) as GAG-binding toxins - On the path from structure to cardiotoxicity and inflammation

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    [[abstract]]Glycosaminoglycans (GAGs) represent the sulfated carbohydrate moieties of proteoglycans which occur abundantly in tissues of the cardiovascular system. Many proteins bind specifically to GAGs and perform an important role in inflammation, cell proliferation, and blood coagulation processes. Recently, in vitro GAG-binding studies of cardiotoxins (CTXs) and basic phospholipase A(2) (PLA(2)) from cobra venom established the toxins as two new families of GAG-binding proteins. In particular discontinuous basic residues in beta-sheet CTXs may, form a cationic cradle suitable for heparin binding as in the case of fibronectin module III-13. The binding specificity of beta-sheet proteins to different GAGs can be further enhanced by involving other cationic clusters near the flexible loop of the molecule. Since the three-dimensional structures of many CTXs and PLA2 are available, these two toxins may serve as models for the elucidation of the molecular recognition of GAG-binding proteins and also as polypeptide templates for further improvement of the binding specificity suitable for future biomedical application. Research along the line of GAG-guided toxicity of cobra venom components may help us to understand the functional role of GAGs and the action mechanism of cobra venom components in the cardiovascular system.[[fileno]]2050135010038[[department]]生科
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