2,165 research outputs found

    Tunable injectable alginate-based hydrogel for cell therapy in Type 1 Diabetes Mellitus

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    Islet transplantation has the potential of reestablishing naturally-regulated insulin production in Type 1 diabetic patients. Nevertheless, this procedure is limited due to the low islet survival after transplantation and the lifelong immunosuppression to avoid rejection. Islet embedding within a biocompatible matrix provides mechanical protection and a physical barrier against the immune system thus, increasing islet survival. Alginate is the preferred biomaterial used for embedding insulin-producing cells because of its biocompatibility, low toxicity and ease of gelation. However, alginate gelation is poorly controlled, affecting its physicochemical properties as an injectable biomaterial. Including different concentrations of the phosphate salt Na2HPO4 in alginate hydrogels, we can modulate their gelation time, tuning their physicochemical properties like stiffness and porosity while maintaining an appropriate injectability. Moreover, these hydrogels showed good biocompatibility when embedding a rat insulinoma cell line, especially at low Na2HPO4 concentrations, indicating that these hydrogels have potential as injectable biomaterials for Type 1 Diabetes Mellitus treatment

    Development and characterization of a microfluidic model of the tumour microenvironment

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    The physical microenvironment of tumours is characterized by heterotypic cell interactions and physiological gradients of nutrients, waste products and oxygen. This tumour microenvironment has a major impact on the biology of cancer cells and their response to chemotherapeutic agents. Despite this, most in vitro cancer research still relies primarily on cells grown in 2D and in isolation in nutrient- and oxygen-rich conditions. Here, a microfluidic device is presented that is easy to use and enables modelling and study of the tumour microenvironment in real-time. The versatility of this microfluidic platform allows for different aspects of the microenvironment to be monitored and dissected. This is exemplified here by real-time profiling of oxygen and glucose concentrations inside the device as well as effects on cell proliferation and growth, ROS generation and apoptosis. Heterotypic cell interactions were also studied. The device provides a live ‘window’ into the microenvironment and could be used to study cancer cells for which it is difficult to generate tumour spheroids. Another major application of the device is the study of effects of the microenvironment on cellular drug responses. Some data is presented for this indicating the device’s potential to enable more physiological in vitro drug screening

    High Energy Physics Opportunities Using Reactor Antineutrinos

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    Nuclear reactors are uniquely powerful, abundant, and flavor-pure sources ofantineutrinos that continue to play a vital role in the US neutrino physicsprogram. The US reactor antineutrino physics community is a diverse interestgroup encompassing many detection technologies and many particle physicstopics, including Standard Model and short-baseline oscillations, BSM physicssearches, and reactor flux and spectrum modeling. The community's aims offerstrong complimentary with numerous aspects of the wider US neutrino program andhave direct relevance to most of the topical sub-groups composing the Snowmass2021 Neutrino Frontier. Reactor neutrino experiments also have a directsocietal impact and have become a strong workforce and technology developmentpipeline for DOE National Laboratories and universities. This white paper,prepared as a submission to the Snowmass 2021 community organizing exercise,will survey the state of the reactor antineutrino physics field and summarizethe ways in which current and future reactor antineutrino experiments can playa critical role in advancing the field of particle physics in the next decade.<br

    Phytoestrogen supplementation and body composition in postmenopausal women: A systematic review and meta-analysis of randomized controlled trials.

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    Phytoestrogen-based medications are commonly used by menopausal women, and especially by obese postmenopausal women, to relieve menopausal symptoms. Substitution of animal with soy protein is often used in weight loss regimens, yet the effect of phytoestrogens, the main constituent of soy foods, on body composition is not completely understood. We conducted a systematic review and meta-analysis to investigate the associations between phytoestrogen supplementation and body weight and the main parameters of body composition in postmenopausal women. A literature search was done using 5 electronic databases from inception to April 2018. Randomized controlled trials (RCTs) with postmenopausal women comparing phytoestrogen supplementation followed by usual diet and placebo were included in the present meta-analysis. From 5932 references, we identified 23 RCTs that met our inclusion criteria, with a total of 1880 postmenopausal women. No association was observed between phytoestrogen supplementation and body weight, body mass index, waist and hip circumference, total fat mass or percentage of body fat. However, the use of phytoestrogens supplementation was associated with a slight decrease in waist-hip ratio; the pooled mean difference was -0.01 cm (95%CI: -0.01 to -0.006). In subgroup analysis, we found a modest decrease in body weight with phytoestrogens supplementation compared with placebo in healthy postmenopausal women [pooled mean difference of changes -0.28 kg (95%CI: -0.52 to -0.04)] and in RCTs with a median number of participants of 66 or less [pooled mean difference of changes -0.49 kg (95%CI: -0.87 to -0.11)]. In contrast, phytoestrogen supplementation was associated with increased body weight in postmenopausal women with preexisting metabolic disorders (prediabetes, type 2 diabetes, prehypertension and hyperlipidemia) [pooled mean difference of changes: 0.78 kg (95%CI: 0.53-1.03)]. In addition, there were some indications that some types of phytoestrogens, such as daidzein, but not soy products or isoflavone mix, could lead to modest adverse changes in body composition in menopausal women. Therefore, future studies should investigate the potential adverse effects of phytoestrogen supplementation on body composition among postmenopausal women

    Glioblastoma on a microfluidic chip: Generating pseudopalisades and enhancing aggressiveness through blood vessel obstruction events

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    Background: Glioblastoma (GBM) is one of the most lethal tumor types. Hypercellular regions, named pseudo- palisades, are characteristic in these tumors and have been hypothesized to be waves of migrating glioblastoma cells.These “waves” of cells are thought to be induced by oxygen and nutrient depletion caused by tumor-induced blood vessel occlusion. Although the universal presence of these structures in GBM tumors suggests that they may play an instrumental role in GBM’s spread and invasion, the recreation of these structures in vitro has remained challenging. Methods: Here we present a new microfluidic model of GBM that mimics the dynamics of pseudopalisade forma- tion.To do this, we embedded U-251 MG cells within a collagen hydrogel in a custom-designed microfluidic device. By controlling the medium flow through lateral microchannels, we can mimic and control blood-vessel obstruction events associated with this disease. Results: Through the use of this new system, we show that nutrient and oxygen starvation triggers a strong migratory process leading to pseudopalisade generation in vitro.These results validate the hypothesis of pseudo- palisade formation and show an excellent agreement with a systems-biology model based on a hypoxia-driven phenomenon. Conclusions: This paper shows the potential of microfluidic devices as advanced artificial systems capable of mod- eling in vivo nutrient and oxygen gradients during tumor evolution

    Daratumumab in combination with urelumab to potentiate anti-myeloma activity in lymphocytedeficient mice reconstituted with human NK cells

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    Daratumumab is an anti-CD38 fully human IgG1 mAb approved for multiple myeloma treatment. One of the proposed mechanisms of action is the induction of antibody-dependent cellular cytotoxicity (ADCC) mediated by NK cells. NK cells acquire surface CD137 expression in the presence of solid-phase-attached daratumumab and when encountering a daratumumab-coated CD38+ tumor cell line. In this setting, addition of the agonist anti-CD137 mAb urelumab enhances NK-cell activation increasing CD25 expression and IFNɣ production. However, in vitro ADCC is not increased by the addition of urelumab both in 4h or 24h lasting experiments. To study urelumab-increased daratumumab-mediated ADCC activity in vivo, we set up a mouse model based on the intravenous administration of a luciferase-transfected multiple myeloma cell line of human origin, human NK cells and daratumumab to immuno-deficient NSG mice. In this model, intravenous administration of urelumab 24h after daratumumab delayed tumor growth and prolonged mice survival

    Height and timing of growth spurt during puberty in young people living with vertically acquired HIV in Europe and Thailand.

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    OBJECTIVE: The aim of this study was to describe growth during puberty in young people with vertically acquired HIV. DESIGN: Pooled data from 12 paediatric HIV cohorts in Europe and Thailand. METHODS: One thousand and ninety-four children initiating a nonnucleoside reverse transcriptase inhibitor or boosted protease inhibitor based regimen aged 1-10 years were included. Super Imposition by Translation And Rotation (SITAR) models described growth from age 8 years using three parameters (average height, timing and shape of the growth spurt), dependent on age and height-for-age z-score (HAZ) (WHO references) at antiretroviral therapy (ART) initiation. Multivariate regression explored characteristics associated with these three parameters. RESULTS: At ART initiation, median age and HAZ was 6.4 [interquartile range (IQR): 2.8, 9.0] years and -1.2 (IQR: -2.3 to -0.2), respectively. Median follow-up was 9.1 (IQR: 6.9, 11.4) years. In girls, older age and lower HAZ at ART initiation were independently associated with a growth spurt which occurred 0.41 (95% confidence interval 0.20-0.62) years later in children starting ART age 6 to 10 years compared with 1 to 2 years and 1.50 (1.21-1.78) years later in those starting with HAZ less than -3 compared with HAZ at least -1. Later growth spurts in girls resulted in continued height growth into later adolescence. In boys starting ART with HAZ less than -1, growth spurts were later in children starting ART in the oldest age group, but for HAZ at least -1, there was no association with age. Girls and boys who initiated ART with HAZ at least -1 maintained a similar height to the WHO reference mean. CONCLUSION: Stunting at ART initiation was associated with later growth spurts in girls. Children with HAZ at least -1 at ART initiation grew in height at the level expected in HIV negative children of a comparable age

    Search for squarks and gluinos in events with isolated leptons, jets and missing transverse momentum at s√=8 TeV with the ATLAS detector

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    The results of a search for supersymmetry in final states containing at least one isolated lepton (electron or muon), jets and large missing transverse momentum with the ATLAS detector at the Large Hadron Collider are reported. The search is based on proton-proton collision data at a centre-of-mass energy s√=8 TeV collected in 2012, corresponding to an integrated luminosity of 20 fb−1. No significant excess above the Standard Model expectation is observed. Limits are set on supersymmetric particle masses for various supersymmetric models. Depending on the model, the search excludes gluino masses up to 1.32 TeV and squark masses up to 840 GeV. Limits are also set on the parameters of a minimal universal extra dimension model, excluding a compactification radius of 1/R c = 950 GeV for a cut-off scale times radius (ΛR c) of approximately 30
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