129 research outputs found

    The Chiral Model of Sakai-Sugimoto at Finite Baryon Density

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    In the context of holographic QCD we analyze Sakai-Sugimoto's chiral model at finite baryon density and zero temperature. The baryon number density is introduced through compact D4 wrapping S^4 at the tip of D8-\bar{D8}. Each baryon acts as a chiral point-like source distributed uniformly over R^3, and leads a non-vanishing U(1)_V potential on the brane. For fixed baryon charge density n_B we analyze the bulk energy density and pressure using the canonical formalism. The baryonic matter with point like sources is always in the spontaneously broken phase of chiral symmetry, whatever the density. The point-like nature of the sources and large N_c cause the matter to be repulsive as all baryon interactions are omega mediated. Through the induced DBI action on D8-\bar{D8}, we study the effects of the fixed baryon charge density n_B on the pion and vector meson masses and couplings. Issues related to vector dominance in matter in the context of holographic QCD are also discussed.Comment: V3: 39 pages, 16 figures, minor corrections, version to appear in JHEP. V2: references added, typos correcte

    Diffusion in an Expanding Plasma using AdS/CFT

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    We consider the diffusion of a non-relativistic heavy quark of fixed mass M, in a one-dimensionally expanding and strongly coupled plasma using the AdS/CFT duality. The Green's function constructed around a static string embedded in a background with a moving horizon, is identified with the noise correlation function in a Langevin approach. The (electric) noise decorrelation is of order 1/T(\tau) while the velocity de-correlation is of order MD(\tau)/T(\tau). For MD>1, the diffusion regime is segregated and the energy loss is Langevin-like. The time dependent diffusion constant D(\tau) asymptotes its adiabatic limit 2/\pi\sqrt{\lambda} T(\tau) when \tau/\tau_0=(1/3\eta_0\tau_0)^3 where \eta_0 is the drag coefficient at the initial proper time \tau_0.Comment: 19 pages, 2 figures, minor corrections, version to appear in JHE

    ULTRAFILTRATED FRACTION OF KOREAN RED GINSENG EXTRACT IMPROVES MEMORY IMPAIRMENT OF TG2576 MICE VIA INHIBITION OF SOLUBLE AÎ’ PRODUCTION AND ACETYLCHOLINESTERASE ACTIVITY

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    Objective: The goal of this study was to research for an effective fraction on memory improvement of Korean red ginseng.Methods: In this study, 80 % ethanol red ginseng extract (RE) was divided into inner fluid (REUI) and outer fluid (REUO) by the ultrafiltration and then REUO was further separated into four fractions namely, REUO-00, REUO-30, REUO-50 and REUO-70, respectively, by Diaion HP-20 column chromatography.Results: REUO has protected more significantly the H2O2-induced SHSY-5Y cell death than REUI. Interestingly, the hydrophobic parts of the REUO (REUO-EtOHs) such as REUO-30,-50 and-70 decreased more significantly the H2O2-induced cell death than its hydrophilic part (REUO-00) in a dose-dependent manner. Then, we focused on the activity of a candidate for cholinergic functions, because memory deficits of neurodegenerative diseases are closely associated with cholinergic dysfunctions. The REUO-EtOHs (1.25 mg/ml) inhibited the activity of the acetylcholinesterase and its half maximal inhibitory concentration (IC50) was about 2.358 mg/ml. Additionally, we investigated whether the intake of the REUO (50 mg/kg/d) during 12 w could improve memory impairment of 12-month old Tg2576 mice and decrease total soluble amyloid-β (Aβ) proteins in the mouse brain cortex. The REUO alleviated significantly the memory impairment and successfully reduced the levels of the soluble Aβ proteins in the mouse cortex.Conclusion: We finally suggest that the REUO, including majorly its hydrophobic part that may be considered as more effective for memory improvement, will be highly considered as valuable candidate for the memory-enhancing ingredients against cholinergic dysfunctions and cognitive impairments of neurodegenerative diseases including Alzheimer's disease.Keywords: Ginseng, Alzheimer's disease, Acetylcholinesterase, Ultrafiltration, MemoryÂ

    The Baryonic Phase in Holographic Descriptions of the QCD Phase Diagram

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    We study holographic models of the QCD temperature-chemical potential phase diagram based on the D3/D7 system with chiral symmetry breaking. The baryonic phase may be included through linked D5-D7 systems. In a previous analysis of a model with a running gauge coupling a baryonic phase was shown to exist to arbitrarily large chemical potential. Here we explore this phase in a more generic phenomenological setting with a step function dilaton profile. The change in dilaton generates a linear confining qˉq\bar{q}q potential and opposes the screening effect of temperature. We show that the persistence of the baryonic phase depends on the step size and that QCD-like phase diagrams can be described. The baryonic phase's existence is qualitatively linked to the existence of confinement in Wilson loop computations in the background.Comment: 21 pages, 7 figure

    Efficacy of fixed-dose amlodipine and losartan combination compared with amlodipine monotherapy in stage 2 hypertension: a randomized, double blind, multicenter study

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    <p>Abstract</p> <p>Background</p> <p>The objective of this trial was to compare the blood-pressure lowering efficacy of amlodipine/losartan combination with amlodipine monotherapy after 6 weeks of treatment in Korean patients with stage 2 hypertension.</p> <p>Results</p> <p>In this multi-center, double-blind, randomized study, adult patients (n = 148) with stage 2 hypertension were randomized to amlodipine 5 mg/losartan 50 mg or amlodipine 5 mg. After 2 weeks, patients with systolic blood pressure (SBP) > 140 mmHg were titrated to amlodipine 10 mg/losartan 50 mg or amlodipine 10 mg. After 4 weeks of titration, hydrochlorothiazide 12.5 mg could be optionally added to both groups. The change from baseline in SBP was assessed after 6 weeks. The responder rate (defined as achieving SBP < 140 mmHg or DBP < 90 mmHg) was also assessed at 2, 6 and 8 weeks as secondary endpoints. Safety and tolerability were assessed through adverse event monitoring and laboratory testing. Baseline demographics and clinical characteristics were generally similar between treatment groups. Least-square mean reduction in SBP at 6 weeks (primary endpoint) was significantly greater in the combination group (36.5 mmHg vs. 31.6 mmHg; p = 0.0117). The responder rate in SBP (secondary endpoints) was significantly higher in the combination group at 2 weeks (52.1% vs. 33.3%; p = 0.0213) but not at 6 weeks (p = 0.0550) or 8 weeks (p = 0.0592). There was no significant difference between groups in the incidence of adverse events.</p> <p>Conclusion</p> <p>These results demonstrate that combination amlodipine/losartan therapy provides an effective and generally well-tolerated first line therapy for reducing blood pressure in stage 2 hypertensive patients.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov: <a href="http://www.clinicaltrials.gov/ct2/show/NCT01127217">NCT01127217</a></p

    Profiles of Multidrug Resistance Protein-1 in the Peripheral Blood Mononuclear Cells of Patients with Refractory Epilepsy

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    BACKGROUND: About one third of patients with epilepsy become refractory to therapy despite receiving adequate medical treatment, possibly from multidrug resistance. P-glycoprotein, encoded by multidrug resistance protein-1 (MDR1) gene, at the blood brain barrier is considered as a major factor mediating drug efflux and contributing to resistance. Given that peripheral blood mononuclear cells (PBMNCs) express MDR1, we investigated a MDR1 status of PBMNCs in various subsets of epilepsy patients and demonstrated their association with clinical characteristics. METHODOLOGY/PRINCIPAL FINDINGS: Clinical and MDR1 data were collected from 140 patients with epilepsy, 30 healthy volunteers, and 20 control patients taking anti-epileptic drugs. PBMNCs were isolated, and basal MDR1 levels and MDR1 conformational change levels were measured by flow cytometry. MDR1 profiles were analyzed according to various clinical parameters, including seizure frequency and number of medications used in epilepsy patients. Epilepsy patients had a higher basal MDR1 level than non-epilepsy groups (p<0.01). Among epilepsy patients, there is a tendency for higher seizure frequency group to have higher basal MDR1 level (p = 0.059). The MDR1 conformational change level was significantly higher in the high-medication-use group than the low-use group (p = 0.028). Basal MDR1 (OR = 1.16 [95% CI: 1.060-1.268]) and conformational change level (OR = 1.11 [95% CI: 1.02-1.20]) were independent predictors for seizure frequency and number of medications, respectively. CONCLUSIONS/SIGNIFICANCE: The MDR1 profile of PBMNCs is associated with seizure frequency and medication conditions in patients with epilepsy

    Oncogenic CagA Promotes Gastric Cancer Risk via Activating ERK Signaling Pathways: A Nested Case-Control Study

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    Background: CagA cellular interaction via activation of the ERK signaling pathway may be a starting point in the development of gastric cancer. This study aimed to evaluate whether genes involved in ERK downstream signaling pathways activated by CagA are susceptible genetic markers for gastric cancer. Methods: In the discovery phase, a total of 580 SNPs within +/-5 kbp of 30 candidate genes were genotyped to examine an association with gastric cancer risk in the Korean Multi-center Cancer Cohort (100 incident gastric cancer case-control sets). The most significant SNPs (raw or permutated p value??0.02) identified in the discovery analysis were re-evaluated in the extension phase using unconditional logistic regression model (400 gastric cancer case-control sets). Combined analyses including pooled-and meta-analysis were conducted to summarize all the results. Results: 24 SNPs in eight genes (ERK, Dock180, C3G, Rap1, Src, CrkL, Mek and Crk) were significantly associated with gastric cancer risk in the individual SNP analyses in the discovery phase (p??0.05). In the extension analyses, ERK rs5999749, Dock180 rs4635002 and C3G rs7853122 showed marginally significant gene-dose effects for gastric cancer. Consistently, final combined analysis presented the SNPs as significantly associated with gastric cancer risk (OR = 1.56, [95% CI: 1.19-2.06], OR = 0.61, [95% CI: 0.43-0.87], OR = 0.59, [95% CI: 0.54-0.76], respectively). Conclusions: Our findings suggest that ERK rs5999749, Dock180 rs4635002 and C3G rs7853122 are genetic determinants in gastric carcinogenesis

    Genetic Susceptibility on CagA-Interacting Molecules and Gene-Environment Interaction with Phytoestrogens: A Putative Risk Factor for Gastric Cancer

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    OBJECTIVES: To evaluate whether genes that encode CagA-interacting molecules (SRC, PTPN11, CRK, CRKL, CSK, c-MET and GRB2) are associated with gastric cancer risk and whether an interaction between these genes and phytoestrogens modify gastric cancer risk. METHODS: In the discovery phase, 137 candidate SNPs in seven genes were analyzed in 76 incident gastric cancer cases and 322 matched controls from the Korean Multi-Center Cancer Cohort. Five significant SNPs in three genes (SRC, c-MET and CRK) were re-evaluated in 386 cases and 348 controls in the extension phase. Odds ratios (ORs) for gastric cancer risk were estimated adjusted for age, smoking, H. pylori seropositivity and CagA strain positivity. Summarized ORs in the total study population (462 cases and 670 controls) were presented using pooled- and meta-analysis. Plasma concentrations of phytoestrogens (genistein, daidzein, equol and enterolactone) were measured using the time-resolved fluoroimmunoassay. RESULTS: SRC rs6122566, rs6124914, c-MET rs41739, and CRK rs7208768 showed significant genetic effects for gastric cancer in both the pooled and meta-analysis without heterogeneity (pooled OR = 3.96 [95% CI 2.05-7.65], 1.24 [95% CI = 1.01-1.53], 1.19 [95% CI = 1.01-1.41], and 1.37 [95% CI = 1.15-1.62], respectively; meta OR = 4.59 [95% CI 2.74-7.70], 1.36 [95% CI = 1.09-1.70], 1.20 [95% CI = 1.00-1.44], and 1.32 [95% CI = 1.10-1.57], respectively). Risk allele of CRK rs7208768 had a significantly increased risk for gastric cancer at low phytoestrogen levels (p interaction<0.05). CONCLUSIONS: Our findings suggest that SRC, c-MET and CRK play a key role in gastric carcinogenesis by modulating CagA signal transductions and interaction between CRK gene and phytoestrogens modify gastric cancer risk

    Genomic Relationships, Novel Loci, and Pleiotropic Mechanisms across Eight Psychiatric Disorders

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    Genetic influences on psychiatric disorders transcend diagnostic boundaries, suggesting substantial pleiotropy of contributing loci. However, the nature and mechanisms of these pleiotropic effects remain unclear. We performed analyses of 232,964 cases and 494,162 controls from genome-wide studies of anorexia nervosa, attention-deficit/hyper-activity disorder, autism spectrum disorder, bipolar disorder, major depression, obsessive-compulsive disorder, schizophrenia, and Tourette syndrome. Genetic correlation analyses revealed a meaningful structure within the eight disorders, identifying three groups of inter-related disorders. Meta-analysis across these eight disorders detected 109 loci associated with at least two psychiatric disorders, including 23 loci with pleiotropic effects on four or more disorders and 11 loci with antagonistic effects on multiple disorders. The pleiotropic loci are located within genes that show heightened expression in the brain throughout the lifespan, beginning prenatally in the second trimester, and play prominent roles in neurodevelopmental processes. These findings have important implications for psychiatric nosology, drug development, and risk prediction.Peer reviewe
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