450 research outputs found

    Role of MicroRNA in Smoking–Induced Periodontitis

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    Stem cells participate in tissue restoration and therapies. The oral cavity, the site of smoking exposure, contains stem cells which are involved in the development, maintenance, and repair of oral tissues. By residing in the oral cavity, stem cells are exposed to and susceptible to the effects of smoking. Periodontitis has been associated with increased incidences of other illnesses such as cardiovascular diseases. We hypothesis that smoking suppression of stem cell potentials by miRNAs is a separate and independent pathway than the pathway via the nicotine receptor activation. Smoking perturbs miRNA expression, resulting in decreased stem cell regeneration potential that delays healing of periodontitis

    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

    Polarimetry and the High-Energy Emission Mechanisms in Quasar Jets. The Case of PKS 1136-135

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    Since the discovery of kiloparsec-scale X-ray emission from quasar jets, the physical processes responsible for their high-energy emission have been poorly defined. A number of mechanisms are under active debate, including synchrotron radiation, inverse-Comptonized CMB (IC/CMB) emission, and other Comptonization processes. In a number of cases, the optical and X-ray emission of jet regions are inked by a single spectral component, and in those, high- resolution multi-band imaging and polarimetry can be combined to yield a powerful diagnostic of jet emission processes. Here we report on deep imaging photometry of the jet of PKS 1136-135 obtained with the {\it Hubble Space Telescope.} We find that several knots are highly polarized in the optical, with fractional polarization Π>30\Pi>30%. When combined with the broadband spectral shape observed in these regions, this is very difficult to explain via IC/CMB models, unless the scattering particles are at the lowest-energy tip of the electron energy distribution, with Lorentz factor γ1\gamma \sim 1, and the jet is also very highly beamed (δ20\delta \geq 20) and viewed within a few degrees of the line of sight. We discuss both the IC/CMB and synchrotron interpretation of the X-ray emission in the light of this new evidence, presenting new models of the spectral energy distribution and also the matter content of this jet. The high polarizations do not completely rule out the possibility of IC/CMB optical-to-X-ray emission in this jet, but they do strongly disfavor the model. We discuss the implications of this finding, and also the prospects for future work.Comment: 14 pages, 8 figures, ApJ in pres

    A randomized, controlled clinical trial: the effect of mindfulness-based cognitive therapy on generalized anxiety disorder among Chinese community patients: protocol for a randomized trial

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    <b>Background</b> Research suggests that an eight-week Mindfulness-Based Cognitive Therapy (MBCT) program may be effective in the treatment of generalized anxiety disorders. Our objective is to compare the clinical effectiveness of the MBCT program with a psycho-education programme and usual care in reducing anxiety symptoms in people suffering from generalized anxiety disorder.<p></p> <b>Methods and Design</b> A three armed randomized, controlled clinical trial including 9-month post-treatment follow-up is proposed. Participants screened positive using the Structure Clinical Interview for DSM-IV (SCID) for general anxiety disorder will be recruited from community-based clinics. 228 participants will be randomly allocated to the MBCT program plus usual care, psycho-education program plus usual care or the usual care group. Validated Chinese version of instruments measuring anxiety and worry symptoms, depression, quality of life and health service utilization will be used. Our primary end point is the change of anxiety and worry score (Beck Anxiety Inventory and Penn State Worry Scale) from baseline to the end of intervention. For primary analyses, treatment outcomes will be assessed by ANCOVA, with change in anxiety score as the baseline variable, while the baseline anxiety score and other baseline characteristics that significantly differ between groups will serve as covariates.<p></p> <b>Discussion</b> This is a first randomized controlled trial that compare the effectiveness of MBCT with an active control, findings will advance current knowledge in the management of GAD and the way that group intervention can be delivered and inform future research

    The atm-1 gene is required for genome stability in Caenorhabditis elegans

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    The Ataxia-telangiectasia-mutated (ATM) gene in humans was identified as the basis of a rare autosomal disorder leading to cancer susceptibility and is now well known as an important signal transducer in response to DNA damage. An approach to understanding the conserved functions of this gene is provided by the model system, Caenorhabditis elegans. In this paper we describe the structure and loss of function phenotype of the ortholog atm-1. Using bioinformatic and molecular analysis we show that the atm-1 gene was previously misannotated. We find that the transcript is in fact a product of three gene predictions, Y48G1BL.2 (atm-1), K10E9.1, and F56C11.4 that together make up the complete coding region of ATM-1. We also characterize animals that are mutant for two available knockout alleles, gk186 and tm5027. As expected, atm-1 mutant animals are sensitive to ionizing radiation. In addition, however, atm-1 mutants also display phenotypes associated with genomic instability, including low brood size, reduced viability and sterility. We document several chromosomal fusions arising from atm-1 mutant animals. This is the first time a mutator phenotype has been described for atm-1 in C. elegans. Finally we demonstrate the use of a balancer system to screen for and capture atm-1-derived mutational events. Our study establishes C. elegans as a model for the study of ATM as a mutator potentially leading to the development of screens to identify therapeutic targets in humans

    A Solvable Regime of Disorder and Interactions in Ballistic Nanostructures, Part I: Consequences for Coulomb Blockade

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    We provide a framework for analyzing the problem of interacting electrons in a ballistic quantum dot with chaotic boundary conditions within an energy ETE_T (the Thouless energy) of the Fermi energy. Within this window we show that the interactions can be characterized by Landau Fermi liquid parameters. When gg, the dimensionless conductance of the dot, is large, we find that the disordered interacting problem can be solved in a saddle-point approximation which becomes exact as gg\to\infty (as in a large-N theory). The infinite gg theory shows a transition to a strong-coupling phase characterized by the same order parameter as in the Pomeranchuk transition in clean systems (a spontaneous interaction-induced Fermi surface distortion), but smeared and pinned by disorder. At finite gg, the two phases and critical point evolve into three regimes in the um1/gu_m-1/g plane -- weak- and strong-coupling regimes separated by crossover lines from a quantum-critical regime controlled by the quantum critical point. In the strong-coupling and quantum-critical regions, the quasiparticle acquires a width of the same order as the level spacing Δ\Delta within a few Δ\Delta's of the Fermi energy due to coupling to collective excitations. In the strong coupling regime if mm is odd, the dot will (if isolated) cross over from the orthogonal to unitary ensemble for an exponentially small external flux, or will (if strongly coupled to leads) break time-reversal symmetry spontaneously.Comment: 33 pages, 14 figures. Very minor changes. We have clarified that we are treating charge-channel instabilities in spinful systems, leaving spin-channel instabilities for future work. No substantive results are change
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