1,588 research outputs found

    Somatostatin receptors differentially affect spontaneous epileptiform activity in mouse hippocampal slices

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    Somatostatin-14 (SRIF) reduces hippocampal epileptiform activity but the contribution of its specific receptors (sst1-5) is poorly understood. We have focused on sst1 and sst2 role in mediating SRIF modulation of epilepsy using hippocampal slices of wild type (WT) and sst1 or sst2 knock out (KO) mice. Recordings of epileptiform discharge induced by Mg2+-free medium with 4-aminopyridine were performed from the CA3 region before and after the application of SRIF compounds. In WT mice, SRIF and the sst1 agonist CH-275 reduce epilepsy whereas sst1 blockade with its antagonist SRA-880 increases bursting discharge. Activation of sst2 does not affect bursting frequency unless its agonist octreotide is applied with SRA-880, indicating that sst1 masks sst2-mediated modulation of epilepsy. In sst1 KO mice: i. bursting frequency is lower than in WT; ii. SRIF, CH-275 and SRA-880 are ineffective on epilepsy; iii. octreotide is also devoid of effects, whereas blockade of sst2 with the antagonist D-Tyr8 Cyn 154806 increases bursting frequency. In sst2 KO mice, SRIF ligand effects are similar to those in WT. In the whole hippocampus of sst1 KO mice, sst2 mRNA, protein and binding are higher than in WT and RT-PCR of the CA3 subarea confirms an increase of the sst2 messenger. We conclude that sst1 mediates inhibitory actions of SRIF and that interactions between sst1 and sst2 may prevent sst2 modulation of epilepsy. We suggest that, in sst1 KO mice, activation of over-expressed sst2 reduces bursting frequency, indicating that sst2 density represents the rate-limiting factor for sst2-mediated modulation of epilepsy.L'articolo è disponibile sul sito dell'editore http://onlinelibrary.wiley.com

    Biological activity of somatostatin receptors in GC rat tumour somatotrophs: evidence with sst1-sst5 receptor-selective nonpeptidyl agonists

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    The physiological actions of somatostatin-14 (SRIF) receptor subtypes (sst1-sst5), which are endogenously expressed in GC cells, have not yet been elucidated, although there is evidence that sst2 receptors are negatively coupled to cytosolic free Ca2+ concentration ([Ca2+]i) and cAMP accumulation. In addition, both sst1 and sst2 receptors are negatively coupled to growth hormone (GH) secretion in GC cells. Here we report on studies concerning the expression, the pharmacology and the functional role of native SRIF receptors in GC cells with the use of five nonpeptidyl agonists, highly selective for each of the SRIF receptors. Radioligand binding studies show that sst2 and sst5 receptors are present at different relative densities, while the presence of sst3 and sst4 receptors appears to be negligible. The absence of sst1 receptor binding was unexpected in view of sst1 receptor functional effects on GH secretion. This suggests very efficient receptor-effector coupling of a low density population of sst1 receptors. Functionally, only sst2 receptors are coupled to the inhibition of [Ca2+]i and cAMP accumulation and the selective activation of sst5 receptors facilitates the stimulation of adenylyl cyclase activity through Gi/o proteins. This effect was not observed when sst2 and sst5 receptors were simultaneously activated, suggesting that there is a functional interaction between sst2 and sst5 receptors. In addition, sst1, sst2 and sst5 receptor activation inhibits GH release, further indicating that SRIF can modulate GH secretion in GC cells through mechanisms both dependent and independent on [Ca2+]i and cAMP-dependent pathways. The present data suggest SRIF-mediated functional effects in GC cells to be very diverse and provide compelling arguments to propose that multiple native SRIF receptors expressed in the same cells are not simply redundant, but contribute to marked signalling diversity.L'articolo è disponibile sul sito dell'editore http://www.sciencedirect.com

    Prostate cancer detection rate in men undergoing transperineal template-guided saturation and targeted prostate biopsy

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    OBJECTIVES To compare prostate cancer (PCa) detection rate of transperineal template-guided saturation prostate biopsy (SBx) and multiparametric magnetic resonance imaging (mpMRI)/transrectal ultrasound fusion guided targeted biopsy (TBx). MATERIALS AND METHODS: We prospectively enrolled 392 men who underwent SBx and TBx in case of suspicious lesions from November 2016 to October 2019. Triggers for a biopsy were an elevated prostate-specific antigen (PSA) and/or positive digital rectal examination and only treatment naïve patients without a previous diagnosis of PCa were included. Study inclusion occurred before biopsy and a prebiopsy mpMRI was available in all men. SBx were taken from 20 different locations according to the modified Barzell zones. The primary endpoint was the detection rate of clinically significant PCa (csPCa) and insignificant PCa (ciPCa) by SBx and/or TBx by comparing the two methods alone and in combination. Additional TBx were taken for any prostate imaging-reporting and data system (PI-RADS) lesion ≥3 seen on the mpMRI. csPCa was defined as any Gleason score ≥7 and ciPCa as Gleason score 6. RESULTS A total of 392 men with a median age of 64 years (interquartile range [IQR]: 58-69), a median PSA of 7.0 ng/ml (IQR: 4.8-10.1) were enrolled. Overall, PCa was found in 200 (51%) of all biopsied men, with 158 (79%) being csPCa and 42 (21%) ciPCa. A total of 268 (68%) men with a suspicious mpMRI and underwent a combined TBx and SBx, of whom csPCa was found in 139 (52%). In this subgroup, 116/139 (83%) csPCa would have been detected by TBx alone, and an additional 23 (17%) were found by SBx. Men with a negative mpMRI (PI-RADS < 3, n = 124, 32%) were found to have csPCa in 19 (15%) cases. In patients with a negative mpMRI in combination with a PSA density <0.1 ng/ml2^{2} , only 8% (3/36) had csPCa. If only TBx would have been performed and all men with a negative mpMRI would not have been biopsed, 42/158 (27%) of csPCa would have been missed, and 38/42 (90%) ciPCa would have not been detected. On multivariable analysis, significant predictors of csPCa were increasing PSA (odds ratio, OR: 1.07 [95% confidence interval, CI: 1.03-1.11]), increasing age (OR: 1.07 [95% CI: 1.03-1.11]), PI-RADS score ≥ 3 (OR: 6.49 [95% CI: 3.55-11.89]), and smaller prostate volume (OR: 0.96 [95% CI: 0.95 -0.97] (p < 0.05 for all parameters). CONCLUSION In comparison to SBx, TBx alone detects csPCa in only ¾ of all men with a positive mpMRI lesion. Thus, systematic biopsies in addition to TBx have to be considered at least in some who undergo a prostate biopsy. In men with a negative mpMRI, SBx still detects 15% csPCa, but similarly overdetecting ciPCa. According to our results, low PSA density and negative mpMRI findings could be used to decide which men can safely avoid biopsy

    Performance of the CMS Cathode Strip Chambers with Cosmic Rays

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    The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device in the CMS endcaps. Their performance has been evaluated using data taken during a cosmic ray run in fall 2008. Measured noise levels are low, with the number of noisy channels well below 1%. Coordinate resolution was measured for all types of chambers, and fall in the range 47 microns to 243 microns. The efficiencies for local charged track triggers, for hit and for segments reconstruction were measured, and are above 99%. The timing resolution per layer is approximately 5 ns

    Search for supersymmetry in events with b-quark jets and missing transverse energy in pp collisions at 7 TeV

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    Results are presented from a search for physics beyond the standard model based on events with large missing transverse energy, at least three jets, and at least one, two, or three b-quark jets. The study is performed using a sample of proton-proton collision data collected at sqrt(s) = 7 TeV with the CMS detector at the LHC in 2011. The integrated luminosity of the sample is 4.98 inverse femtobarns. The observed number of events is found to be consistent with the standard model expectation, which is evaluated using control samples in the data. The results are used to constrain cross sections for the production of supersymmetric particles decaying to b-quark-enriched final states in the context of simplified model spectra.Comment: Submitted to Physical Review

    Performance and Operation of the CMS Electromagnetic Calorimeter

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    The operation and general performance of the CMS electromagnetic calorimeter using cosmic-ray muons are described. These muons were recorded after the closure of the CMS detector in late 2008. The calorimeter is made of lead tungstate crystals and the overall status of the 75848 channels corresponding to the barrel and endcap detectors is reported. The stability of crucial operational parameters, such as high voltage, temperature and electronic noise, is summarised and the performance of the light monitoring system is presented

    Optimasi Portofolio Resiko Menggunakan Model Markowitz MVO Dikaitkan dengan Keterbatasan Manusia dalam Memprediksi Masa Depan dalam Perspektif Al-Qur`an

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    Risk portfolio on modern finance has become increasingly technical, requiring the use of sophisticated mathematical tools in both research and practice. Since companies cannot insure themselves completely against risk, as human incompetence in predicting the future precisely that written in Al-Quran surah Luqman verse 34, they have to manage it to yield an optimal portfolio. The objective here is to minimize the variance among all portfolios, or alternatively, to maximize expected return among all portfolios that has at least a certain expected return. Furthermore, this study focuses on optimizing risk portfolio so called Markowitz MVO (Mean-Variance Optimization). Some theoretical frameworks for analysis are arithmetic mean, geometric mean, variance, covariance, linear programming, and quadratic programming. Moreover, finding a minimum variance portfolio produces a convex quadratic programming, that is minimizing the objective function ðð¥with constraintsð ð 𥠥 ðandð´ð¥ = ð. The outcome of this research is the solution of optimal risk portofolio in some investments that could be finished smoothly using MATLAB R2007b software together with its graphic analysis

    Differential cross section measurements for the production of a W boson in association with jets in proton–proton collisions at √s = 7 TeV

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    Measurements are reported of differential cross sections for the production of a W boson, which decays into a muon and a neutrino, in association with jets, as a function of several variables, including the transverse momenta (pT) and pseudorapidities of the four leading jets, the scalar sum of jet transverse momenta (HT), and the difference in azimuthal angle between the directions of each jet and the muon. The data sample of pp collisions at a centre-of-mass energy of 7 TeV was collected with the CMS detector at the LHC and corresponds to an integrated luminosity of 5.0 fb[superscript −1]. The measured cross sections are compared to predictions from Monte Carlo generators, MadGraph + pythia and sherpa, and to next-to-leading-order calculations from BlackHat + sherpa. The differential cross sections are found to be in agreement with the predictions, apart from the pT distributions of the leading jets at high pT values, the distributions of the HT at high-HT and low jet multiplicity, and the distribution of the difference in azimuthal angle between the leading jet and the muon at low values.United States. Dept. of EnergyNational Science Foundation (U.S.)Alfred P. Sloan Foundatio
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