184 research outputs found

    Atmospheric oxygen tension slows myoblast proliferation via mitochondrial activation

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    Mitochondrial activity inhibits proliferation and is required for differentiation of myoblasts. Myoblast proliferation is also inhibited by the ~20% oxygen level used in standard tissue culture. We hypothesize that mitochondrial activity would be greater at hyperoxia (20% O(2)) relative to more physiological oxygen (5% O(2)).Murine primary myoblasts from isolated myofibres and conditionally immortalized H-2K myoblasts were cultured at 5% and 20% oxygen. Proliferation, assayed by cell counts, EdU labeling, and CFSE dilution, was slower at 20% oxygen. Expression of MyoD in primary myoblasts was delayed at 20% oxygen, but myogenicity, as measured by fusion index, was slightly higher. FACS-based measurement of mitochondrial activity indicators and luminometric measurement of ATP levels revealed that mitochondria exhibited greater membrane potential and higher levels of Reactive Oxygen Species (ROS) at 20% oxygen with concomitant elevation of intracellular ATP. Mitochondrial mass was unaffected. Low concentrations of CCCP, a respiratory chain uncoupler, and Oligomycin A, an ATP synthase inhibitor, each increased the rate of myoblast proliferation. ROS were investigated as a potential mechanism of mitochondrial retrograde signaling, but scavenging of ROS levels by N-acetyl-cysteine (NAC) or α-Phenyl-N-tert-butylnitrone (PBN) did not rescue the suppressed rate of cell division in hyperoxic conditions, suggesting other pathways. Primary myoblasts from older mice showed a slower proliferation than those from younger adult mice at 20% oxygen but no difference at 5% oxygen.These results implicate mitochondrial regulation as a mechanistic explanation for myoblast response to oxygen tension. The rescue of proliferation rate in myoblasts of aged mice by 5% oxygen suggests a major artefactual component to age-related decline of satellite cell proliferation in standard tissue culture at 20% oxygen. It lends weight to the idea that these age-related changes result at least in part from environmental factors rather than characteristics intrinsic to the satellite cell

    Association between Participation in Outpatient Cardiac Rehabilitation and Self-Reported Receipt of Lifestyle Advice from a Healthcare Provider: Results of a Population-Based Cross-Sectional Survey

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    We test the hypothesis that the odds of self-reported receipt of lifestyle advice from a health care provider will be lower among outpatient cardiac rehabilitation (OCR) nonattendees and nonreferred patients compared to OCR attendees. Logistic regression was used to analyse cross-sectional data provided by 65% (4971/7678) of patients aged 20 to 84 years discharged from public hospitals with a diagnosis indicating eligibility for OCR between 2002 and 2007. Among respondents, 71% (3518) and 55% (2724) recalled advice regarding physical activity and diet, respectively, while 88% (592/674) of smokers recalled quit advice. OCR attendance was low: 36% (1764) of respondents reported attending OCR, 11% (552) did not attend following referral, and 45% (2217) did not recall being invited. The odds of recalling advice regarding physical activity and diet were significantly lower among OCR nonattendees compared to attendees (OR 0.34, 95% CI 0.21, 0.56 and OR 0.33, 95% CI 0.25, 0.44, resp.) and among nonreferred respondents compared to OCR attendees (OR 0.10, 95% CI 0.07, 0.15 and OR 0.17, 95% CI 0.14, 0.22, resp.). Patients hospitalised for coronary heart disease should be referred to OCR or a suitable alternative to improve recall of lifestyle advice that will reduce the risk of further coronary events

    Association between Participation in Outpatient Cardiac Rehabilitation and Self-Reported Receipt of Lifestyle Advice from a Healthcare Provider: Results of a Population-Based Cross-Sectional Survey

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    We test the hypothesis that the odds of self-reported receipt of lifestyle advice from a health care provider will be lower among outpatient cardiac rehabilitation (OCR) nonattendees and nonreferred patients compared to OCR attendees. Logistic regression was used to analyse cross-sectional data provided by 65% (4971/7678) of patients aged 20 to 84 years discharged from public hospitals with a diagnosis indicating eligibility for OCR between 2002 and 2007. Among respondents, 71% (3518) and 55% (2724) recalled advice regarding physical activity and diet, respectively, while 88% (592/674) of smokers recalled quit advice. OCR attendance was low: 36% (1764) of respondents reported attending OCR, 11% (552) did not attend following referral, and 45% (2217) did not recall being invited. The odds of recalling advice regarding physical activity and diet were significantly lower among OCR nonattendees compared to attendees (OR 0.34, 95% CI 0.21, 0.56 and OR 0.33, 95% CI 0.25, 0.44, resp.) and among nonreferred respondents compared to OCR attendees (OR 0.10, 95% CI 0.07, 0.15 and OR 0.17, 95% CI 0.14, 0.22, resp.). Patients hospitalised for coronary heart disease should be referred to OCR or a suitable alternative to improve recall of lifestyle advice that will reduce the risk of further coronary events

    Investigations To Characterize Multi-Junction Solar Cells In The Stratosphere Using Low-Cost Balloon And Communication Technologies

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    The use of current balloon, control and communication technologies to test multi-junction solar sell in the stratosphere to achieve near AMO conditions have been investigated. The design criteria for the technologies are that they be reliable, low cost and readily available. Progress is reported on a program to design, launch, fly and retrieve payloads dedicated to testing multi-junction solar cells

    Polarization Correlation Measurements of Electron Impact Excitation of Hs2pd at 54.4 eV

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    First direct measurements are reported of the linear reduced Stokes parameters P1,P2 for H(2p) excited by electron impact at the benchmark energy of 54.4 eV. The results differ significantly from previous values deduced from angular correlation measurements which are in serious conflict with all sophisticated theoretical approaches. Our results support the trend of theoretical predictions for P2 and confirm that its value is negative at electron scattering angles above 100±, as predicted by theory

    Polarization Correlation Measurements of Electron Impact Excitation of Hs2pd at 54.4 eV

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    First direct measurements are reported of the linear reduced Stokes parameters P1,P2 for H(2p) excited by electron impact at the benchmark energy of 54.4 eV. The results differ significantly from previous values deduced from angular correlation measurements which are in serious conflict with all sophisticated theoretical approaches. Our results support the trend of theoretical predictions for P2 and confirm that its value is negative at electron scattering angles above 100±, as predicted by theory

    Mediation, translation and local ecologies: understanding the impact of policy levers on FE colleges

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    This article reports the views of managers and tutors on the role of policy ‘levers’ on teaching, learning, and inclusion in colleges of Further Education (FE) in our research project, ‘The impact of policy on learning and inclusion in the Learning and Skills Sector (LSS)’.i Using data from five research visits conducted over two years in eight FE learning sites, we explore the processes by which colleges ‘mediate’ and ‘translate’ national policy levers and how this affects their ability to respond to local need. The paper tentatively develops three related concepts/metaphors to explain the complexity of the policy/college interface – ‘the process of mediation’, ‘acts of translation’ and ‘local ecologies’. We found that policy levers interacted with a complex set of national, local and institutional factors as colleges responded to pressures from the external environment and turned these into internal plans, systems and practices. We conclude by suggesting that national policy-makers, who design national policy levers, may not be fully aware of these complexities and we make the case for the benefits of greater local control over policy levers, where these interactions are better understood

    Islet neogenesis-associated protein signaling in neonatal pancreatic rat islets: Involvement of the cholinergic pathway

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    Islet neogenesis associated protein (INGAP) increases islet mass and insulin secretion in neonatal and adult rat islets. In the present study, we measured the short- and long-term effects of INGAP-PP (a pentadecapeptide having the 104-118 amino acid sequence of INGAP) upon islet protein expression and phosphorylation of components of the P13K, MAPK and cholinergic pathways, and on insulin secretion. Short-term exposure of neonatal islets to INGAP-PP (90 s, 5, 15, and 30 min) significantly increased Akt1-Ser473 and MAPK3/1-Thr202/ Tyr204 phosphorylation and INGAP-PP also acutely increased insulin secretion from islets perifused with 2 and 20 mM glucose. Islets cultured for 4 days in the presence of INGAP-PP showed an increased expression of Akt1, Frap1, and Mapk1 mRNAs as well as of the muscarinic M3 receptor subtype, and phospholipase C (PLC)-β2 proteins. These islets also showed increased Akt1 and MAPK3/1 protein phosphorylation. Brief exposure of INGAP-PP-treated islets to carbachol (Cch) significantly increased P70S6K-Thr389 and MAPK3/1 phosphorylation and these islets released more insulin when challenged with Cch that was prevented by the M3 receptor antagonist 4-DAMP, in a concentration-dependent manner. In conclusion, these data indicate that short- and long-term exposure to INGAP-PP significantly affects the expression and the phosphorylation of proteins involved in islet P13K and MAPK signaling pathways. The observations of INGAPP-PP-stimulated up-regulation of cholinergic M3 receptors and PLC- proteins, enhanced P70S6K and MAPK3/1 phosphorylation and Cch-induced insulin secretion suggest a participation of the cholinergic pathway in INGAP-PP-mediated effects.Facultad de Ciencias MédicasCentro de Endocrinología Experimental y Aplicad

    Clinical Study Association between Participation in Outpatient Cardiac Rehabilitation and Self-Reported Receipt of Lifestyle Advice from a Healthcare Provider: Results of a Population-Based Cross-Sectional Survey

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    We test the hypothesis that the odds of self-reported receipt of lifestyle advice from a health care provider will be lower among outpatient cardiac rehabilitation (OCR) nonattendees and nonreferred patients compared to OCR attendees. Logistic regression was used to analyse cross-sectional data provided by 65% (4971/7678) of patients aged 20 to 84 years discharged from public hospitals with a diagnosis indicating eligibility for OCR between 2002 and 2007. Among respondents, 71% (3518) and 55% (2724) recalled advice regarding physical activity and diet, respectively, while 88% (592/674) of smokers recalled quit advice. OCR attendance was low: 36% (1764) of respondents reported attending OCR, 11% (552) did not attend following referral, and 45% (2217) did not recall being invited. The odds of recalling advice regarding physical activity and diet were significantly lower among OCR nonattendees compared to attendees (OR 0.34, 95% CI 0.21, 0.56 and OR 0.33, 95% CI 0.25, 0.44, resp.) and among nonreferred respondents compared to OCR attendees (OR 0.10, 95% CI 0.07, 0.15 and OR 0.17, 95% CI 0.14, 0.22, resp.). Patients hospitalised for coronary heart disease should be referred to OCR or a suitable alternative to improve recall of lifestyle advice that will reduce the risk of further coronary events

    Association between participation in outpatient cardiac rehabilitation and self-reported receipt of lifestyle advice from a healthcare provider: results of a population-based cross-sectional survey

    Get PDF
    We test the hypothesis that the odds of self-reported receipt of lifestyle advice from a health care provider will be lower among outpatient cardiac rehabilitation (OCR) nonattendees and nonreferred patients compared to OCR attendees. Logistic regression was used to analyse cross-sectional data provided by 65% (4971/7678) of patients aged 20 to 84 years discharged from public hospitals with a diagnosis indicating eligibility for OCR between 2002 and 2007. Among respondents, 71% (3518) and 55% (2724) recalled advice regarding physical activity and diet, respectively, while 88% (592/674) of smokers recalled quit advice. OCR attendance was low: 36% (1764) of respondents reported attending OCR, 11% (552) did not attend following referral, and 45% (2217) did not recall being invited. The odds of recalling advice regarding physical activity and diet were significantly lower among OCR nonattendees compared to attendees (OR 0.34, 95% CI 0.21, 0.56 and OR 0.33, 95% CI 0.25, 0.44, resp.) and among nonreferred respondents compared to OCR attendees (OR 0.10, 95% CI 0.07, 0.15 and OR 0.17, 95% CI 0.14, 0.22, resp.). Patients hospitalised for coronary heart disease should be referred to OCR or a suitable alternative to improve recall of lifestyle advice that will reduce the risk of further coronary events
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