570 research outputs found

    Long-Term Follow-Up of Intravitreal Ranibizumab for the Treatment of Choroidal Neovascularization due to Choroidal Osteoma

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    Choroidal osteoma is an uncommon benign osseous intraocular tumor that typically affects young adult women. Choroidal neovascularization (CNV) is one of the complications that can develop in eyes with choroidal osteoma. We present a case of CNV secondary to choroidal osteoma treated with intravitreal ranibizumab. A 57-year-old lady presented with painless loss of vision with a right-eye visual acuity of 20/800. Fundus examination showed a well-demarcated yellowish peripapillary choroidal osteoma with associated retinal and subretinal hemorrhage due to CNV. Three intravitreal ranibizumab injections at monthly intervals were given and her visual acuity improved to 20/30 following treatment. After 1.2 years of follow-up, the right eye visual acuity was maintained at 20/30 with no evidence of CNV recurrence. Our findings suggest that intravitreal ranibizumab may be an effective therapeutic option for treating CNV secondary to choroidal osteoma

    Cyclophosphamide induces NR2B phosphorylation-dependent facilitation on spinal reflex potentiation

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    Chang CH, Peng HY, Wu HC, Lai CY, Hsieh MC, Lin TB. Cyclophosphamide induces NR2B phosphorylation-dependent facilitation on spinal reflex potentiation. Am J Physiol Renal Physiol 300: F692-F699, 2011. First published November 24, 2010; doi:10.1152/ajprenal.00531.2010.-It is well-established that cyclophosphamide (CYP) can sensitize the pelvic afferent nerve arising from the urinary bladder and therefore induce suprapubic pain. To test the possibility that CYP might mediate the development of visceral hypereflexia/hyperalgesia by facilitating spinal activity-dependent neural plasticity, we compared the pelvic-urethra reflex activity and spinal N-methyl-D-aspartate receptor NR2B subunit (NR2B) phosphorylation in rats treated with vehicle solution and CYP. Compared with vehicle solution, when accompanied by upregulation of phosphorylated NR2B expression in the lumbosacral (L6-S2) dorsal horn, CYP increased the evoked spikes in spinal reflex potentiation induced by repetitive stimulation (1 stimulation/1 s). Moreover, intraperitoneal pretreatments with N(G)-nitro-L-arginine methyl ester and roscovitine, nitric oxide synthase and cyclin-dependent protein kinase 5 (Cdk5) antagonists, respectively, overwrote CYP-enhanced reflex potentiation and NR2B phosphorylation. When compared with the untreated group, the treatment with small-interfering RNA of NR2B, which decreased the expression of NR2B expression, abolished CYP-dependent reflex facilitation and spinal NR2B phosphorylation. These results suggested that CYP might facilitate spinal reflex potentiation mediated by N-methyl-D-aspartate receptors and participate in the development of visceral hypereflexia/hyperalgesia through nitric oxide-and Cdk5-dependent NR2B phosphorylation at the lumbosacral dorsal horn

    Measurement of the Intrinsic Radiopurity of Cs-137/U-235/U-238/Th-232 in CsI(Tl) Crystal Scintillators

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    The inorganic crystal scintillator CsI(Tl) has been used for low energy neutrino and Dark Matter experiments, where the intrinsic radiopurity is an issue of major importance. Low-background data were taken with a CsI(Tl) crystal array at the Kuo-Sheng Reactor Neutrino Laboratory. The pulse shape discrimination capabilities of the crystal, as well as the temporal and spatial correlations of the events, provide powerful means of measuring the intrinsic radiopurity of Cs-137 as well as the U-235, U-238 and Th-232 series. The event selection algorithms are described, with which the decay half-lives of Po-218, Po-214, Rn-220, Po-216 and Po-212 were derived. The measurements of the contamination levels, their concentration gradients with the crystal growth axis, and the uniformity among different crystal samples, are reported. The radiopurity in the U-238 and Th-232 series are comparable to those of the best reported in other crystal scintillators. Significant improvements in measurement sensitivities were achieved, similar to those from dedicated massive liquid scintillator detector. This analysis also provides in situ measurements of the detector performance parameters, such as spatial resolution, quenching factors, and data acquisition dead time.Comment: 28 pages, 12 figure

    CKM Favored Semileptonic Decays of Heavy Hadrons at Zero Recoil

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    We study the properties of Cabibbo-Kobayashi-Maskawa (CKM) favored semileptonic decays of mesons and baryons containing a heavy quark at the point of no recoil. We first use a diagrammatic analysis to rederive the result observed by earlier authors that at this kinematic point the BB meson decays via bcb\to c transitions can only produce a DD or DD^* meson. The result is generalized to include photon emissions which violate heavy quark flavor symmetry. We show that photons emitted by the heavy quarks and the charged lepton are the only light particles that can decorate the decays BˉD(D)+ν\bar{B}\to D(D^*) + \ell\nu at zero recoil, and the similar processes of heavy baryons. Implications for the determinations of the CKM parameter VcbV_{cb} are discussed. Also studied in this paper is the connection between our diagrammatic analysis of suppression of particle emission and the formal observation based on weak currents at zero recoil being generators of heavy quark symmetry. We show that the two approaches can be unified by considering the Isgur-Wise function in the presence of an external source.Comment: 27 pages, including 11 figures using macros FEYNMAN.te

    EphrinB2 induces pelvic-urethra reflex potentiation via Src kinase-dependent tyrosine phosphorylation of NR2B

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    Wu HC, Chang CH, Peng HY, Chen GD, Lai CY, Hsieh MC, Lin TB. EphrinB2 induces pelvic-urethra reflex potentiation via Src kinase-dependent tyrosine phosphorylation of NR2B. Am J Physiol Renal Physiol 300: F403-F411, 2011. First published December 8, 2010; doi:10.1152/ajprenal.00520.2010.-Recently, the role of EphB receptor (EphBR) tyrosine kinase and their ephrinB ligands in pain-related neural plasticity at the spinal cord level have been identified. To test whether Src-family tyrosine kinase-dependent glutamatergic N-methyl-D-aspartate receptor NR2B subunit phosphorylation underlies lumbosacral spinal EphBR activation to mediate pelvic-urethra reflex potentiation, we recorded external urethra sphincter electromyogram reflex activity and analyzed protein expression in the lumbosacral (L(6)-S(2)) dorsal horn in response to intrathecal ephrinB2 injections. When compared with vehicle solution, exogenous ephrinB2 (5 mu g/rat it)-induced reflex potentiation, in associated with phosphorylation of EphB1/2, Src-family kinase, NR2B Y1336 and Y1472 tyrosine residues. Both intrathecal EphB1 and EphB2 immunoglobulin fusion protein (both 10 mu g/rat it) prevented ephrinB2-dependent reflex potentiation, as well as protein phosphorylation. Pretreatment with PP2 (50 mu M, 10 mu l it), an Src-family kinase antagonist, reversed the reflex potentiation, as well as Src kinase and NR2B phosphorylation. Together, these results suggest the ephrinB2-dependent EphBR activation, which subsequently provokes Src kinase-mediated N-methyl-D-aspartate receptor NR2B phosphorylation in the lumbosacral dorsal horn, is crucial for the induction of spinal reflex potentiation contributing to the development of visceral pain and/or hyperalgesia in the pelvic area

    Immune-modulation by polyclonal IgM treatment reduces atherosclerosis in hypercholesterolemic apoE−/− mice

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    AbstractObjectiveGamma-globulin treatment reduces experimental atherosclerosis by modulating immune function; however the effect of IgM on atherosclerosis is not known. We investigated the effect of serum-derived, non-immune polyclonal IgM (Poly-IgM) on atherosclerosis in mice with advanced disease and also assessed its immune-modulatory effects.Methods and resultsAortic atherosclerosis was assessed in apoE−/− mice fed atherogenic diet starting at 6 weeks of age. In addition, mice were also subjected to perivascular cuff injury to the carotid artery at 25 weeks of age to induce accelerated atherosclerosis. At the time of injury, the mice were treated weekly with a commercially available Poly-IgM (0.4mg/mouse) or PBS for 4 weeks and euthanized at 29 weeks of age. Poly-IgM reduced aortic atherosclerosis, and reduced lesion size in the aortic sinus and injured carotid artery, without significant changes in serum cholesterol levels. Poly-IgM treatment was associated with increased anti-oxLDL IgG titers and a reduction in the % splenic CD4+ T cells compared to controls. The splenic CD4+ T cell cultured from the Poly-IgM treated mice had reduced proliferation in vitro compared with controls.ConclusionPoly-IgM treatment reduced aortic and accelerated carotid atherosclerosis in apoE−/− mice in association with increased anti-oxLDL IgG titers, and reduced number and proliferative function of splenic CD4+ T cells. Our study identifies a novel athero-protective and immunomodulatory role for non-immune polyclonal IgM

    Studies of Prototype CsI(Tl) Crystal Scintillators for Low-Energy Neutrino Experiments

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    Crystal scintillators provide potential merits for the pursuit of low-energy low-background experiments. A CsI(Tl) scintillating crystal detector is being constructed to study low-energy neutrino physics at a nuclear reactor, while projects are underway to adopt this technique for dark matter searches. The choice of the geometrical parameters of the crystal modules, as well as the optimization of the read-out scheme, are the results of an R&D program. Crystals with 40 cm in length were developed. The detector requirements and the achieved performance of the prototypes are presented. Future prospects for this technique are discussed.Comment: 32 pages, 14 figure

    School Closure and Mitigation of Pandemic (H1N1) 2009, Hong Kong

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    In Hong Kong, kindergartens and primary schools were closed when local transmission of pandemic (H1N1) 2009 was identified. Secondary schools closed for summer vacation shortly afterwards. By fitting a model of reporting and transmission to case data, we estimated that transmission was reduced ≈25% when secondary schools closed

    The Proton Spin and Flavor Structure in the Chiral Quark Model

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    After a pedagogical review of the simple constituent quark model and deep inelastic sum rules, we describe how a quark sea as produced by the emission of internal Goldstone bosons by the valence quarks can account for the observed features of proton spin and flavor structures. Some issues concerning the strange quark content of the nucleon are also discussed.Comment: 59 pages with table of contents, Lecture delivered at the Schladming Winter School (March 1997), to be published by Springer-Verlag under the title "Computing Particle Properties" (eds. C. B. Lang and H. Gausterer
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