191 research outputs found

    Stem Cell Based Tissue Engineering and Regenerative Medicine: A Review Focusing on Adult Stem Cells

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    Tissue engineering has emerged as a field that attempts to harness the bodies\u27 own developmental and repair features to treat diseases and illnesses. Many of these illnesses are caused by necrosis or loss of functionality of complete organs or specific cell types. Early discoveries in embryonic stem cells fueled a wave of research that led to claims about possibly regenerating nonfunctioning organs. Although we are still far away from being able to grow functional organs in a Petri dish, the field continues to progress forward, and new clinical trials have been approved for using both embryonic and adult stem cell based solutions for regenerative medicine and tissue engineering. Current trends have moved towards adult stem cells for cell based therapies as they offer an autologous source and are less tumorigenic than their embryonic and induced-pluripotent stem cell counter parts. This review will begin with an outline of stem cell classes and then focus on current therapies in myocardial tissue repair, neural tissue repair, diabetes, as well as osteogenic and chondrogenic differentiation are also reviewed

    Progress of Mesenchymal Stem Cell Therapy for Neural and Retinal Diseases

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    Complex circuitry and limited regenerative power make central nervous system (CNS) disorders the most challenging and difficult for functional repair. With elusive disease mechanisms, traditional surgical and medical interventions merely slow down the progression of the neurodegenerative diseases. However, the number of neurons still diminishes in many patients. Recently, stem cell therapy has been proposed as a viable option. Mesenchymal stem cells (MSCs), a widely-studied human adult stem cell population, have been discovered for more than 20 years. MSCs have been found all over the body and can be conveniently obtained from different accessible tissues: bone marrow, blood, and adipose and dental tissue. MSCs have high proliferative and differentiation abilities, providing an inexhaustible source of neurons and glia for cell replacement therapy. Moreover, MSCs also show neuroprotective effects without any genetic modification or reprogramming. In addition, the extraordinary immunomodulatory properties of MSCs enable autologous and heterologous transplantation. These qualities heighten the clinical applicability of MSCs when dealing with the pathologies of CNS disorders. Here, we summarize the latest progress of MSC experimental research as well as human clinical trials for neural and retinal diseases. This review article will focus on multiple sclerosis, spinal cord injury, autism, glaucoma, retinitis pigmentosa and age-related macular degeneration

    Pluripotent Adult Stem Cells: A Potential Revolution in Regenerative Medicine and Tissue Engineering

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    Stem cells have generated a lot of excitement among the researchers, clinicians and the public alike. Various types of stem cells are being evaluated for their regenerative potential. Marginal benefit resulting by transplanting autologus stem cells (deemed to be absolutely safe) in various clinical conditions has been proposed to be a growth factor effect rather than true regeneration. In contrast, various pre-clinical studies have been undertaken, using differentiated cells from embryonic stem cells or induced pluripotent stem cells have shown promise, functional improvement and no signs of teratoma formation. The scientists are not in a rush to reach the clinic but a handful of clinical studies have shown promise. This book is a collection of studies/reviews, beginning with an introduction to the pluripotent stem cells and covering various aspects like derivation, differentiation, ethics, etc., and hence would provide insight into the recent standing on the pluripotent stem cells biology. The chapters have been categorized into three sections, covering subjects ranging from the generation of pluripotent stem cells and various means of their derivation from embryonic as well as adult tissues, the mechanistic understanding of pluripotency and narrating the potential therapeutic implications of these in vitro generated cells in various diseases, in addition to the associated pros and cons in the same.https://nsuworks.nova.edu/cnso_bio_facbooks/1014/thumbnail.jp

    A Methodology and Simulation-Based Toolchain for Estimating Deployment Performance of Smart Collective Services at the Edge

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    Research trends are pushing artificial intelligence (AI) across the Internet of Things (IoT)-edge-fog-cloud continuum to enable effective data analytics, decision making, as well as the efficient use of resources for QoS targets. Approaches for collective adaptive systems (CASs) engineering, such as aggregate computing, provide declarative programming models and tools for dealing with the uncertainty and the complexity that may arise from scale, heterogeneity, and dynamicity. Crucially, aggregate computing architecture allows for 'pulverization': applications can be decomposed into many deployable micromodules that can be spread across the ICT infrastructure, thus allowing multiple potential deployment configurations for the same application logic. This article studies the deployment architecture of aggregate-based edge services and its implications in terms of performance and cost. The goal is to provide methodological guidelines and a model-based toolchain for the generation and simulation-based evaluation of potential deployments. First, we address this subject methodologically by proposing an approach based on deployment code generators and a simulation phase whose obtained solutions are assessed with respect to their performance and costs. We then tailor this approach to aggregate computing applications deployed onto an IoT-edge-fog-cloud infrastructure, and we develop a corresponding toolchain based on Protelis and EdgeCloudSim. Finally, we evaluate the approach and tools through a case study of edge multimedia streaming, where the edge ecosystem exhibits intelligence by self-organizing into clusters to promote load balancing in large-scale dynamic settings

    STAT3 Impairs STAT5 Activation in the Development of IL-9-Secreting T Cells

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    Th cell subsets develop in response to multiple activating signals, including the cytokine environment. IL-9-secreting T cells develop in response to the combination of IL-4 and TGF-β, although they clearly require other cytokine signals, leading to the activation of transcription factors including STAT5. In Th17 cells, there is a molecular antagonism of STAT5 with STAT3 signaling, although whether this paradigm exists in other Th subsets is not clear. In this paper, we demonstrate that STAT3 attenuates the ability of STAT5 to promote the development of IL-9-secreting T cells. We demonstrate that production of IL-9 is increased in the absence of STAT3 and cytokines that result in a sustained activation of STAT3, including IL-6, have the greatest potency in repressing IL-9 production in a STAT3-dependent manner. Increased IL-9 production in the absence of STAT3 correlates with increased endogenous IL-2 production and STAT5 activation, and blocking IL-2 responses eliminates the difference in IL-9 production between wild-type and STAT3-deficient T cells. Moreover, transduction of developing Th9 cells with a constitutively active STAT5 eliminates the ability of IL-6 to reduce IL-9 production. Thus, STAT3 functions as a negative regulator of IL-9 production through attenuation of STAT5 activation and function

    STAT3 activation impairs the stability of Th9 cells

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    Th9 cells regulate multiple immune responses including immunity to pathogens and tumors, allergic inflammation, and autoimmunity. Despite ongoing research into Th9 development and function, little is known about the stability of the Th9 phenotype. In this report we demonstrate that IL-9 production is progressively lost in Th9 cultures over several rounds of differentiation. The loss of IL-9 is not due to an outgrowth of cells that do not secrete IL-9, as purified IL-9 secretors demonstrate the same loss of IL-9 in subsequent rounds of differentiation. The loss of IL-9 production correlates with increases in phospho-STAT3 levels within the cell, and the production of IL-10. STAT3-deficient Th9 cells have increased IL-9 production that is maintained for longer in culture than IL-9 in control cultures. IL-10 is responsible for STAT3 activation during the first round of differentiation, and contributes to instability in subsequent rounds of culture. Together, our results indicate that environmental cues dictate the instability of the Th9 phenotype, and suggest approaches to enhance Th9 activity in beneficial immune responses

    Estudio descriptivo: valoración de autoeficacia percibida en la alimentación de estudiantes universitarios

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    Introduction: Self-efficacy refers to personal ability to control one's own behavior, being able to adopt a beneficial behavior and stop practicing one that would be harmful. Its assessment as a tool in health field is becoming increasingly important. The objectives were assess perceived self-efficacy in university students related to eating behaviors considered healthy and determine possible differences between careers. Methods: A psychometric test of food self-efficacy was used, validated and adapted to the Argentine food culture. The instrument was made up of 20 items, with a response option according to the Likert scale (1: lack of ability; 5: being very capable), corresponding to 4 categories: high-fat foods; healthy food; sweet foods and healthy drinks. Participants included 300 students from 3 careers: Biochemistry (BQ) and Bachelor's degrees in Biotechnology (BB) and Nutrition (BN). Results: The reliability of the instrument was 0.83 (Cronbach's Alpha). Population included 80% women and 20% men, 21 ± 4 years old. The healthy drinks category received the highest score, without observing statistical differences between careers (4.47, 4.37 and 4.37). The score obtained by BN corresponds to a greater sense of perceived self-efficacy than BQ and BB (respectively) in: foods high in fat (3.76 vs 3.31 and 3.50; p=0.001); healthy food (4.23 vs 3.75 and 3.90 p=0.003) and sweet foods (3.71 vs 3.53 and 3.55; p=0.016). Conclusions: It is assumed that the assessment of self-efficacy is an important predictor of the actions of individuals in various situations, resulting in a valuable tool to elucidate the particularities and promote nutritional food education in university students of different careers.Introducción: La autoeficacia refiere a la capacidad personal de controlar la propia conducta, siendo capaz de adoptar una beneficiosa y/o dejar de practicar una que resultaría dañina. Su valoración en el ámbito de la salud cobra cada vez más importancia. El objetivo del trabajo fue valorar en universitarios la autoeficacia percibida en conductas alimentarias consideradas saludables y determinar posibles diferencias entre carreras. Métodos: Se empleó un test psicométrico de autoeficacia alimentaria, validado y adaptado a la cultura alimentaria argentina, con opción de respuesta según escala de Likert (1: ausencia de capacidad; 5: ser muy capaz), correspondientes a 4 categorías: alimentos altos en grasa; alimentos dulces; alimentos saludables y bebidas saludables. Participaron 300 estudiantes, 80% mujeres y 20% varones, de 21±4 años, de tres carreras: Bioquímica (BQ) y las Licenciaturas en Biotecnología (LB) y en Nutrición (LN). Resultados: La confiabilidad del instrumento fue 0,83 (Alfa de Cronbach). La categoría bebidas saludables recibió la mayor puntuación, sin observar diferencias estadísticas entre carreras (4,47; 4,37 y 4,37). La puntuación obtenida por LN se correspondió con un mayor sentido de autoeficacia percibida que BQ y LB (respectivamente) en alimentos: altos en grasa (3,76 vs 3,31 y 3,50; p= 0,001); dulces (3,71 vs 3,53 y 3,55; p= 0,016) y saludables (4,23 vs 3,75 y 3,90 p=0,003). Conclusión: Siendo la valoración de la autoeficacia un importante predictor de las acciones de los individuos frente a diversas situaciones, resulta una herramienta valiosa para dilucidar las particularidades y promover la educación alimentaria nutricional en universitarios de diferentes carreras

    Relationships between lake transparency, thermocline depth, and sediment oxygen demand in Arctic lakes

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    The burial of organic matter within lake sediments can be a significant component of landscape carbon cycling. Whether organic matter deposited in lake sediments is sequestered or mineralized depends on factors limiting the decomposition rate of organic matter, such as temperature and the availability of oxygen. In stratified lakes, the distribution of temperature and oxygen is determined by the depth of the thermocline, and therefore sediment organic matter burial should be sensitive to changes in thermocline depth. Using a survey of more than 30 lakes over 3 years in the Alaskan Arctic, we found that thermocline depth during the summer was positively correlated with water transparency. Furthermore, using sediment incubations from 3 lakes, we found that variation in sediment oxygen demand is primarily affected by variation in temperature and the availability of oxygen with limited effect of the source of the sediments. Because variation in temperature and oxygen concentration in stratified lakes is mainly determined by the depth of thermocline, these results indicate that changes in transparency can have indirect effects on the rate of organic matter mineralization in lakes. A reduction in thermocline depth that results from decreased lake transparency may decrease the breakdown of sediment organic matter and increase the storage of organic carbon in lake sediments

    Brain-derived neurotrophic factor is associated with human muscle satellite cell differentiation in response to muscle-damaging exercise

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    Muscle satellite cell (SC) regulation is a complex process involving many key signalling molecules. Recently, the neurotrophin brain-derived neurotropic factor (BDNF) has implicated in SC regulation in animals. To date, little is known regarding the role of BDNF in human SC function in vivo. Twenty-nine males (age, 21 ± 0.5 years) participated in the study. Muscle biopsies from the thigh were obtained prior to a bout of 300 maximal eccentric contractions (Pre), and at 6 h, 24 h, 72 h, and 96 h postexercise. BDNF was not detected in any quiescent (Pax7+/MyoD−) SCs across the time-course. BDNF colocalized to 39% ± 5% of proliferating (Pax7+/MyoD+) cells at Pre, which increased to 84% ± 3% by 96 h (P < 0.05). BDNF was only detected in 13% ± 5% of differentiating (Pax7−/MyoD+) cells at Pre, which increased to 67% ± 4% by 96 h (P < 0.05). The number of myogenin+ cells increased 95% from Pre (1.6 ± 0.2 cells/100 myofibres (MF)) at 24 h (3.1 ± 0.3 cells/100 MF) and remained elevated until 96 h (cells/100 MF), P < 0.05. The proportion of BDNF+/myogenin+ cells was 26% ± 0.3% at Pre, peaking at 24 h (49% ± 3%, P < 0.05) and remained elevated at 96 h (P < 0.05). These data are the first to demonstrate an association between SC proliferation and differentiation and BDNF expression in humans in vivo, with BDNF colocalization to SCs increasing during the later stages of proliferation and early differentiation
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