987 research outputs found

    Effect of Age and Lipoperoxidation in Rat and Human Adipose Tissue-Derived Stem Cells

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    A wide range of clinical applications in regenerative medicine were opened decades ago with the discovery of adult stem cells. Highly promising adult stem cells are mesenchymal stem/stromal cells derived from adipose tissue (ADSCs), primarily because of their abundance and accessibility. These cells have multipotent properties and have been used extensively to carry out autologous transplants. However, the biology of these cells is not entirely understood. Among other factors, the regeneration capacity of these cells will depend on both their capacity of proliferation/differentiation and the robustness of the biochemical pathways that allow them to survive under adverse conditions like those found in damaged tissues. The transcription factors, such as Nanog and Sox2, have been described as playing an important role in stem cell proliferation and differentiation. Also, the so-called longevity pathways, in which AMPK and SIRT1 proteins play a crucial role, are essential for cell homeostasis under stressful situations. These pathways act by inhibiting the translation through downregulation of elongation factor-2 (eEF2). In order to deepen knowledge of mesenchymal stem cell biology and which factors are determinant in the final therapeutic output, we evaluate in the present study the levels of all of these proteins in the ADSCs from humans and rats and how these levels are affected by aging and the oxidative environment. Due to the effect of aging and oxidative stress, our results suggest that before performing a cell therapy with ADSCs, several aspects reported in this study such as oxidative stress status and proliferation and differentiation capacity should be assessed on these cells. This would allow us to know the robustness of the transplanted cells and to predict the therapeutic result, especially in elder patients, where probably ADSCs do not carry out their biological functions in an optimal way

    Early Science with the Large Millimetre Telescope: Molecules in the Extreme Outflow of a proto-Planetary Nebula

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    Extremely high velocity emission likely related to jets is known to occur in some proto-Planetary Nebulae. However, the molecular complexity of this kinematic component is largely unknown. We observed the known extreme outflow from the proto-Planetary Nebula IRAS 16342-3814, a prototype water fountain, in the full frequency range from 73 to 111 GHz with the RSR receiver on the Large Millimetre Telescope. We detected the molecules SiO, HCN, SO, and 13^{13}CO. All molecular transitions, with the exception of the latter are detected for the first time in this source, and all present emission with velocities up to a few hundred km s1^{-1}. IRAS 16342-3814 is therefore the only source of this kind presenting extreme outflow activity simultaneously in all these molecules, with SO and SiO emission showing the highest velocities found of these species in proto-Planetary Nebulae. To be confirmed is a tentative weak SO component with a FWHM \sim 700 km s1^{-1}. The extreme outflow gas consists of dense gas (nH2>_{\rm H_2} > 104.8^{4.8}--105.7^{5.7} cm3^{-3}), with a mass larger than \sim 0.02--0.15 M_{\odot}. The relatively high abundances of SiO and SO may be an indication of an oxygen-rich extreme high velocity gas.Comment: Accepted for publication in Monthly Notices of the Royal Astronomical Society Letter

    Developmental programing of thirst and sodium appetite

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    Thirst and sodium appetite are the sensations responsible for the motivated behaviors of water and salt intake, respectively, and both are essential responses for the maintenance of hydromineral homeostasis in animals. These sensations and their related behaviors develop very early in the postnatal period in animals. Many studies have demonstrated several pre- and postnatal stimuli that are responsible for the developmental programing of thirst and sodium appetite and, consequently, the pattern of water and salt intake in adulthood in need-free or need-induced conditions. The literature systematically reports the involvement of dietary changes, hydromineral and cardiovascular challenges, renin-angiotensin system and steroid hormone disturbances, and lifestyle in these developmental factors. Therefore, this review will address how pre- and postnatal challenges can program lifelong thirst and sodium appetite in animals and humans, as well as which neuroendocrine substrates are involved. In addition, the possible epigenetic molecular mechanisms responsible for the developmental programing of drinking behavior, the clinical implications of hydromineral disturbances during pre- and postnatal periods, and the developmental origins of adult hydromineral behavior will be discussed.Fil: Mecawi, Andre S.. Universidade Federal Rural do Rio de Janeiro; Brasil. University of Malaysia; MalasiaFil: Macchione, Ana Fabiola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Universidad Nacional de Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra; ArgentinaFil: Nuñez, Paula. Universidad de Oviedo; EspañaFil: Perillan, Carmen. Universidad de Oviedo; EspañaFil: Reis, Luis C.. Universidade Federal Rural do Rio de Janeiro; BrasilFil: Vivas, Laura Marta. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Universidad Nacional de Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra; ArgentinaFil: Arguelles, Juan. Universidad de Oviedo; Españ

    Mammalian expression of the human sex steroid-binding protein of plasma (SBP or SHBG) and testis (ABP) Characterization of the recombinant protein

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    AbstractA full-length 1,209 bp cDNA encoding the human sex steroid-binding protein of plasma (SBP or SHBG) and testis (ABP) was constructed and expressed in BHK-21 cells. The sequence agrees with the published gene and protein sequences. The cells were found to secrete SBP following transfection and G418r selection. The recombinant protein binds 5α-dihydrotestosterone with a Kd of 0.28 nM. It also binds testosterone and 17β-estradiol but not progesterone, estrone or cortisol revealing a steroid-binding specificity identical to that of human SBP, SDS-PAGE patterns are less complex than human SBP and show a monomeric molecular weight of about 43 kDa

    Search for annihilating dark matter in the Sun with 3 years of IceCube data

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    We present results from an analysis looking for dark matter annihilation in the Sun with the IceCube neutrino telescope. Gravitationally trapped dark matter in the Sun’s core can annihilate into Standard Model particles making the Sun a source of GeV neutrinos. IceCube is able to detect neutrinos with energies >100 GeV while its low-energy infill array DeepCore extends this to >10 GeV. This analysis uses data gathered in the austral winters between May 2011 and May 2014, corresponding to 532 days of livetime when the Sun, being below the horizon, is a source of up-going neutrino events, easiest to discriminate against the dominant background of atmospheric muons. The sensitivity is a factor of two to four better than previous searches due to additional statistics and improved analysis methods involving better background rejection and reconstructions. The resultant upper limits on the spin-dependent dark matter-proton scattering cross section reach down to 1.46×10−5 pb for a dark matter particle of mass 500 GeV annihilating exclusively into τ+τ−particles. These are currently the most stringent limits on the spin-dependent dark matter-proton scattering cross section for WIMP masses above 50 GeV.M. G. Aartsen ... G. C. Hill ... S. Robertson ... A. Wallace … B. J. Whelan ... et al. (IceCube Collaboration

    All-flavour search for neutrinos from dark matter annihilations in the Milky Way with IceCube/DeepCore

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    Published online: 28 September 2016We present the first IceCube search for a signal of dark matter annihilations in the Milky Way using all-flavour neutrino-induced particle cascades. The analysis focuses on the DeepCore sub-detector of IceCube, and uses the surrounding IceCube strings as a veto region in order to select starting events in the DeepCore volume. We use 329 live-days of data from IceCube operating in its 86-string configuration during 2011–2012. No neutrino excess is found, the final result being compatible with the background-only hypothesis. From this null result, we derive upper limits on the velocity-averaged self-annihilation cross-section, 〈σAv〉, for dark matter candidate masses ranging from 30 GeV up to 10 TeV, assuming both a cuspy and a flat-cored dark matter halo profile. For dark matter masses between 200 GeV and 10 TeV, the results improve on all previous IceCube results on 〈σAv〉 , reaching a level of 10⁻²³ cm³ s⁻¹, depending on the annihilation channel assumed, for a cusped NFW profile. The analysis demonstrates that all-flavour searches are competitive with muon channel searches despite the intrinsicallyworse angular resolution of cascades compared to muon tracks in IceCube.M.G. Aartsen … G.C. Hill … S. Robertson … A. Wallace … B.J. Whelan … et al. (IceCube Collaboration

    First search for dark matter annihilations in the Earth with the IceCube detector

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    Published online: 8 February 2017We present the results of the first IceCube search for dark matter annihilation in the center of the Earth. Weakly interacting massive particles (WIMPs), candidates for dark matter, can scatter off nuclei inside the Earth and fall below its escape velocity. Over time the captured WIMPs will be accumulated and may eventually self-annihilate. Among the annihilation products only neutrinos can escape from the center of the Earth. Large-scale neutrino telescopes, such as the cubic kilometer IceCube Neutrino Observatory located at the South Pole, can be used to search for such neutrino fluxes. Data from 327 days of detector livetime during 2011/2012 were analyzed. No excess beyond the expected background from atmospheric neutrinos was detected. The derived upper limits on the annihilation rate of WIMPs in the Earth and the resulting muon flux are an order of magnitude stronger than the limits of the last analysis performed with data from IceCube’s predecessor AMANDA. The limits can be translated in terms of a spin-independent WIMP–nucleon cross section. For a WIMP mass of 50 GeV this analysis results in the most restrictive limits achieved with IceCube data.M.G. Aartsen … G.C. Hill … S. Robertson … A. Wallace … B.J. Whelan … et al. (IceCube Collaboration

    Development of a general analysis and unfolding scheme and its application to measure the energy spectrum of atmospheric neutrinos with IceCube

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    We present the development and application of a generic analysis scheme for the measurement of neutrino spectra with the IceCube detector. This scheme is based on regularized unfolding, preceded by an event selection which uses a Minimum Redundancy Maximum Relevance algorithm to select the relevant variables and a random forest for the classification of events. The analysis has been developed using IceCube data from the 59-string configuration of the detector. 27,771 neutrino candidates were detected in 346 days of livetime. A rejection of 99.9999 % of the atmospheric muon background is achieved. The energy spectrum of the atmospheric neutrino flux is obtained using the TRUEE unfolding program. The unfolded spectrum of atmospheric muon neutrinos covers an energy range from 100 GeV to 1 PeV. Compared to the previous measurement using the detector in the 40-string configuration, the analysis presented here, extends the upper end of the atmospheric neutrino spectrum by more than a factor of two, reaching an energy region that has not been previously accessed by spectral measurements.M.G. Aartsen … G.C. Hill … S. Robertson … B. Whelan … et al. (IceCube Collaboration
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