988 research outputs found

    Low Connexin Channel-Dependent Intercellular Communication in Human Adult Hematopoietic Progenitor/Stem Cells: Probing Mechanisms of Autologous Stem Cell Therapy

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    Human bone marrow is a clinical source of autologous progenitor stem cells showing promise for cardiac repair following ischemic insult. Functional improvements following delivery of adult bone marrow CD34+ cells into heart tissue may require metabolic/electrical communication between participating cells. Since connexin43 (Cx43) channels are implicated in cardiogenesis and provide intercellular connectivity in the heart, the authors analyzed the expression of 20 connexins (Cx) in CD34+ cells and in monocytes and granulocytes in bone marrow and spinal cord. Reverse transcriptase-polymerase chain reaction (RT-PCR) detected only low expression of Cx43 and Cx37. Very low level dye coupling was detected by flow cytometry between CD34+ cells and other Cx43 expressing cells, including HL-1 cardiac cells, and was not inhibited by specific gap junction inhibitors. The results indicate that CD34+ cells are unlikely to communicate via gap junctions and the authors conclude that use of CD34+ cells to repair damaged hearts is unlikely to involve gap junctions. The results concur with the hypothesis that bone marrow cells elicit improved cardiac function through release of undefined paracrine mediators

    Using Performance Assessments to Connect Fractions and Rational Expressions: Noyce Scholars as Mentors to Pre-Service Elementary Teachers

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    At Georgia Southern University, Noyce scholars are not only being mentored, but they are also serving as mentors to preservice elementary teachers. One topic that proves to be problematic for many students is the conceptual understanding of fractions and rational expressions. Since our Noyce scholars with mathematics degrees will be teaching algebra, it is important that they are fluent with the arithmetic to algebra connection. In addition, it is crucial that these mathematics majors become stakeholders in mathematics education at the elementary school level. Performance assessments can provide the structure necessary for assisting pre-service elementary teachers in firmly establishing the arithmetic to algebra connection. This session showcases a performance assessment where students are not only required to connect concrete models with standard fraction algorithms, but are also required to explain these connections. In this performance assessment, fraction bars are used with the number line in order to establish the arithmetic to algebra connection. Noyce scholars assist by helping and evaluating these pre-service teachers. By participating, not only do Noyce scholars support elementary teachers, but they also gain strategies and resources needed to teach fractions in a way that leads to conceptual understanding

    Mental states as macrostates emerging from brain electrical dynamics

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    Psychophysiological correlations form the basis for different medical and scientific disciplines, but the nature of this relation has not yet been fully understood. One conceptual option is to understand the mental as “emerging” from neural processes in the specific sense that psychology and physiology provide two different descriptions of the same system. Stating these descriptions in terms of coarser- and finer-grained system states (macro- and microstates), the two descriptions may be equally adequate if the coarse-graining preserves the possibility to obtain a dynamical rule for the system. To test the empirical viability of our approach, we describe an algorithm to obtain a specific form of such a coarse-graining from data, and illustrate its operation using a simulated dynamical system. We then apply the method to an electroencephalographic recording, where we are able to identify macrostates from the physiological data that correspond to mental states of the subject

    A mitochondria-targeted mass spectrometry probe to detect glyoxals: implications for diabetes

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    The glycation of protein and nucleic acids that occurs as a consequence of hyperglycaemia disrupts cell function and contributes to many pathologies, including those associated with diabetes and aging. Intracellular glycation occurs following the generation of the reactive 1,2-dicarbonyls methylglyoxal and glyoxal and disruption to mitochondrial function is associated with hyperglycemia. However, the contribution of these reactive dicarbonyls to mitochondrial damage in pathology is unclear due to uncertainties about their levels within mitochondria in cells and in vivo. To address this we have developed a mitochondria-targeted reagent (MitoG) designed to assess the levels of mitochondrial dicarbonyls within cells. MitoG comprises a lipophilic triphenylphosphonium cationic function, which directs the molecules to mitochondria within cells and an o-phenylenediamine moiety that reacts with dicarbonyls to give distinctive and stable products. The extent of accumulation of these diagnostic heterocyclic products can be readily and sensitively quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS), enabling changes to be determined. Using the MitoG-based analysis we assessed the formation of methylglyoxal and glyoxal in response to hyperglycaemia in cells in culture and in the Akita mouse model of diabetes in vivo. These findings indicated that the levels of methylglyoxal and glyoxal within mitochondria increase during hyperglycaemia in both cells and in vivo, suggesting that they can contribute to the pathological mitochondrial dysfunction that occurs in diabetes and aging

    Targeting the Ataxia Telangiectasia Mutated-null Phenotype in Chronic Lymphocytic Leukemia with Pro-oxidants

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    Inactivation of the Ataxia Telangiectasia Mutated gene in chronic lymphocytic leukemia results in resistance to p53-dependent apoptosis and inferior responses to treatment with DNA damaging agents. Hence, p53-independent strategies are required to target Ataxia Telangiectasia Mutated-deficient chronic lymphocytic leukemia. As Ataxia Telangiectasia Mutated has been implicated in redox homeostasis, we investigated the effect of the Ataxia Telangiectasia Mutated-null chronic lymphocytic leukemia genotype on cellular responses to oxidative stress with a view to therapeutic targeting. We found that in comparison to Ataxia Telangiectasia Mutated-wild type chronic lymphocytic leukemia, pro-oxidant treatment of Ataxia Telangiectasia Mutated-null cells led to reduced binding of NF-E2 p45-related factor-2 to antioxidant response elements and thus decreased expression of target genes. Furthermore, Ataxia Telangiectasia Mutated-null chronic lymphocytic leukemia cells contained lower levels of antioxidants and elevated mitochondrial reactive oxygen species. Consequently, Ataxia Telangiectasia Mutated-null chronic lymphocytic leukemia, but not tumours with 11q deletion or TP53 mutations, exhibited differentially increased sensitivity to pro-oxidants both in vitro and in vivo. We found that cell death was mediated by a p53- and caspase-independent mechanism associated with apoptosis inducing factor activity. Together, these data suggest that defective redox-homeostasis represents an attractive therapeutic target for Ataxia Telangiectasia Mutated-null chronic lymphocytic leukemia

    Incorporating psychology into cyber security education: A pedagogical approach

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    The role of the human in cyber security is well acknowledged. Many cyber security incidents rely upon targets performing specific behavioural actions, such as opening a link within a phishing email. Cyber adversaries themselves are driven by psychological processes such as motivation, group dynamics and social identity. Furthermore, both intentional and unintentional insider threats are associated with a range of psychological factors, including cognitive load, mental wellbeing, trust and interpersonal relations. By incorporating psychology into cyber security education, practitioners will be better equipped with the skills they need to address cyber security issues. However, there are challenges in doing so. Psychology is a broad discipline, and many theories, approaches and methods may have little practical significance to cyber security. There is a need to sift through the literature to identify what can be applied to cyber security. There are also pedagogical differences in how psychology and cyber security are taught and also psychological differences in the types of student that may typically study psychology and cyber security. To engage with cyber security students, it is important that these differences are identified and positively addressed. Essential to this endeavor is the need to discuss and collaborate across the two disciplines. In this paper, we explore these issues and discuss our experiences as psychology and cyber security academics who work across disciplines to deliver psychology education to cyber security students, practitioners and commercial clients

    Mitochondrial Genetic Background Modulates Bioenergetics and Susceptibility to Acute Cardiac Volume Overload

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    Dysfunctional bioenergetics has emerged as a key feature in many chronic pathologies such as diabetes and cardiovascular disease. This has led to the mitochondrial paradigm in which it has been proposed that mtDNA sequence variation contributes to disease susceptibility. In the present study we show a novel animal model of mtDNA polymorphisms, the MNX (mitochondrial–nuclear exchange) mouse, in which the mtDNA from the C3H/HeN mouse has been inserted on to the C57/BL6 nuclear background and vice versa to test this concept. Our data show a major contribution of the C57/BL6 mtDNA to the susceptibility to the pathological stress of cardiac volume overload which is independent of the nuclear background. Mitochondria harbouring the C57/BL6J mtDNA generate more ROS (reactive oxygen species) and have a higher mitochondrial membrane potential relative to those with C3H/HeN mtDNA, independent of nuclear background. We propose this is the primary mechanism associated with increased bioenergetic dysfunction in response to volume overload. In summary, these studies support the ‘mitochondrial paradigm’ for the development of disease susceptibility, and show that the mtDNA modulates cellular bioenergetics, mitochondrial ROS generation and susceptibility to cardiac stress

    Sherman, Shakers, and Shenanigans

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    The first 122 pages of this book relate to Bulloch County and form Book 10: Readings in Bulloch County History. The remainder comprise the Southern Folkways Journal Review No. 3, and relate to Southeast Georgia and to the Southeastern region of the United States. The first collection begins with a poem by Dr. John Ransom Lewis, followed by three articles on Dan Bland and the biographies of prominent African American citizens. Also included are two articles on the Hardy Moore family, student papers on vanishing Bulloch County communities, information on Joseph Jackson, articles on three local churches, and the Muster Roll of Toombs Guards. The second section of this book begins with an article on Western Shakers by Dr. Dale Covington, followed by “Hostau Reminisces,” and several articles on the Cherokee and the Lumbee Indians.https://digitalcommons.georgiasouthern.edu/bchs-pubs/1033/thumbnail.jp
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