9,489 research outputs found

    Insulin inhibits cardiac contractility by inducing a Gi-biased β2-adrenergic signaling in hearts.

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    Insulin and adrenergic stimulation are two divergent regulatory systems that may interact under certain pathophysiological circumstances. Here, we characterized a complex consisting of insulin receptor (IR) and β2-adrenergic receptor (β2AR) in the heart. The IR/β2AR complex undergoes dynamic dissociation under diverse conditions such as Langendorff perfusions of hearts with insulin or after euglycemic-hyperinsulinemic clamps in vivo. Activation of IR with insulin induces protein kinase A (PKA) and G-protein receptor kinase 2 (GRK2) phosphorylation of the β2AR, which promotes β2AR coupling to the inhibitory G-protein, Gi. The insulin-induced phosphorylation of β2AR is dependent on IRS1 and IRS2. After insulin pretreatment, the activated β2AR-Gi signaling effectively attenuates cAMP/PKA activity after β-adrenergic stimulation in cardiomyocytes and consequently inhibits PKA phosphorylation of phospholamban and contractile responses in myocytes in vitro and in Langendorff perfused hearts. These data indicate that increased IR signaling, as occurs in hyperinsulinemic states, may directly impair βAR-regulated cardiac contractility. This β2AR-dependent IR and βAR signaling cross-talk offers a molecular basis for the broad interaction between these signaling cascades in the heart and other tissues or organs that may contribute to the pathophysiology of metabolic and cardiovascular dysfunction in insulin-resistant states

    Investigation of Tumor Suppressing Function of CACNA2D3 in Esophageal Squamous Cell Carcinoma.

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    Background: Deletion of 3p is one of the most frequent genetic alterations in esophageal squamous cell carcinoma (ESCC), suggesting the existence of one or more tumor suppressor genes (TSGs) within these regions. In this study, one TSG, CACNA2D3 at 3p21.1, was characterized. Methods: Expression of CACNA2D3 in ESCCs was tested by quantitative real-time PCR and tissue microarray. The mechanism of CACNA2D3 downregulation was investigated by methylation-specific polymerase chain reaction (MS-PCR). The tumor suppressive function of CACNA2D3 was characterized by both in vitro and in vivo tumorigenic assays, cell migration and invasion assays. Results: CACNA2D3 was frequently downregulated in ESCCs (24/48, 50%), which was significantly associated with promoter methylation and allele loss (P<0.05). Tissue microarray result showed that downregulation of CACNA2D3 was detected in (127/224, 56.7%) ESCCs, which was significantly associated with lymph node metastasis (P = 0.01), TNM staging (P = 0.003) and poor outcome of ESCC patients (P<0.05). Functional studies demonstrated that CACNA2D3 could inhibit tumorigenicity, cell motility and induce apoptosis. Mechanism study found that CACNA2D3 could arrest cell cycle at G1/S checkpoint by increasing expressions of p21 and p53 and decreasing expression of CDK2. In addition, CACNA2D3 could upregulate intracellular free cytosolic Ca2+ and subsequently induce apoptosis. Conclusion: CACNA2D3 is a novel TSG responsible to the 3p21 deletion event and plays a critical suppressing role in the development and progression of ESCC. © 2013 Li et al.link_to_OA_fulltex

    A simulation study on the measurement of D0-D0bar mixing parameter y at BES-III

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    We established a method on measuring the \dzdzb mixing parameter yy for BESIII experiment at the BEPCII e+ee^+e^- collider. In this method, the doubly tagged ψ(3770)D0D0\psi(3770) \to D^0 \overline{D^0} events, with one DD decays to CP-eigenstates and the other DD decays semileptonically, are used to reconstruct the signals. Since this analysis requires good e/πe/\pi separation, a likelihood approach, which combines the dE/dxdE/dx, time of flight and the electromagnetic shower detectors information, is used for particle identification. We estimate the sensitivity of the measurement of yy to be 0.007 based on a 20fb120fb^{-1} fully simulated MC sample.Comment: 6 pages, 7 figure

    Climate warming leads to divergent succession of grassland microbial communities

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    Accurate climate projections require an understanding of the effects of warming on ecological communities and the underlying mechanisms that drive them . However, little is known about the effects of climate warming on the succession of microbial communities . Here we examined the temporal succession of soil microbes in a long-term climate change experiment at a tall-grass prairie ecosystem. Experimental warming was found to significantly alter the community structure of bacteria and fungi. By determining the time-decay relationships and the paired differences of microbial communities under warming and ambient conditions, experimental warming was shown to lead to increasingly divergent succession of the soil microbial communities, with possibly higher impacts on fungi than bacteria. Variation partition- and null model-based analyses indicate that stochastic processes played larger roles than deterministic ones in explaining microbial community taxonomic and phylogenetic compositions. However, in warmed soils, the relative importance of stochastic processes decreased over time, indicating a potential deterministic environmental filtering elicited by warming. Although successional trajectories of microbial communities are difficult to predict under future climate change scenarios, their composition and structure are projected to be less variable due to warming-driven selection. 1–3 4,

    Clinical and Biological Implications of Mutational Spectrum in Acute Myeloid Leukemia of FAB Subtypes M0 and M1

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    Background/Aims: Acute myeloid leukemia (AML) of French-American-British (FAB) subtypes M0 and M1 are both poorly differentiated AML, but their mutational spectrum and molecular characteristics remain unknown. This study aimed to explore the mutational spectrum and prognostic factors of AML-M0 and M1. Methods: Sixty-five AML patients derived from The Cancer Genome Atlas (TCGA) database were enrolled in this study. Whole-genome sequencing was performed to depict the mutational spectrum of each patient. Clinical characteristics at diagnosis, including peripheral blood (PB) white blood cell counts (WBC), blast percentages in PB and bone marrow (BM), FAB subtypes and the frequencies of known recurrent genetic mutations were described. Survival was estimated using the Kaplan-Meier methods and log-rank test. Univariate and multivariate Cox proportional hazard models were constructed procedure. Results: Forty-six patients had more than five recurrent genetic mutations. FLT3 had the highest mutation frequency (n=20, 31%), followed by NPM1 (n=18, 28%), DNMT3A (n=16, 25%), IDH1 (n=14, 22%), IDH2 (n=12, 18%), RUNX1 (n=11, 17%) and TET2 (n=7, 11%). Univariate analysis showed that age >= 60 years and TP53 mutations had adverse effect on EFS (P=0.015, P=0.036, respectively) and OS (P=0.003, P=0.004, respectively), WBC count >= 50x10(9)/L and FLT3-ITD negatively affected EFS (P=0.003, P=0.034, respectively), whereas NPM1 mutations had favorable effect on OS (P=0.035) and allogeneic hematopoietic stem cell transplantation (allo-HSCT) on EFS and OS (all P= 50x10(9)/L was an independent risk factor for EFS (P=0.002) and TP53 mutations for OS (P=0.043). Conclusions: Our study provided new insights into the mutational spectrum and molecular signatures of AML-M0 and M1. We proposed that FLT3-ITD, NPM1 and TP53 be identified as markers for risk stratification of AML-M0 and M1. Patients with AML-M0 and M1 would likely benefit from allo-HSCT. (C) 2018 The Author(s) Published by S. Karger AG, Base

    Measurements of Cabibbo Suppressed Hadronic Decay Fractions of Charmed D0 and D+ Mesons

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    Using data collected with the BESII detector at e+ee^{+}e^{-} storage ring Beijing Electron Positron Collider, the measurements of relative branching fractions for seven Cabibbo suppressed hadronic weak decays D0KK+D^0 \to K^- K^+, π+π\pi^+ \pi^-, KK+π+πK^- K^+ \pi^+ \pi^- and π+π+ππ\pi^+ \pi^+ \pi^- \pi^-, D+K0ˉK+D^+ \to \bar{K^0} K^+, KK+π+K^- K^+ \pi^+ and ππ+π+\pi^- \pi^+ \pi^+ are presented.Comment: 11 pages, 5 figure

    The σ\sigma pole in J/ψωπ+πJ/\psi \to \omega \pi^+ \pi^-

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    Using a sample of 58 million J/ψJ/\psi events recorded in the BESII detector, the decay J/ψωπ+πJ/\psi \to \omega \pi^+ \pi^- is studied. There are conspicuous ωf2(1270)\omega f_2(1270) and b1(1235)πb_1(1235)\pi signals. At low ππ\pi \pi mass, a large broad peak due to the σ\sigma is observed, and its pole position is determined to be (541±39)(541 \pm 39) - ii (252±42)(252 \pm 42) MeV from the mean of six analyses. The errors are dominated by the systematic errors.Comment: 15 pages, 6 figures, submitted to PL

    Measurements of ψ(2S)\psi(2S) decays into Vector- Tensor final states

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    Decays of the ψ(2S)\psi(2S) into vector plus tensor meson final states have been studied with 14 million ψ(2S)\psi(2S) events collected with the BESII detector. Branching fractions of \psi(2S) \rt \omega f_{2}(1270), ρa2(1320)\rho a_2(1320), K(892)0Kˉ2(1430)0+c.c.K^*(892)^0\bar{K}^*_2(1430)^0+c.c. and ϕf2(1525)\phi f_2^{\prime}(1525) are determined. They improve upon previous BESI results and confirm the violation of the "12%" rule for ψ(2S)\psi(2S) decays to VT channels with higher precision.Comment: 7 pages, 7 figures and 2 table
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