4,742 research outputs found

    Delivery of human apolipoprotein (apo) E to liver by an [E1(-), E3(-), polymerase(-), pTP(-)] adenovirus vector containing a liver-specific promoter inhibits atherogenesis in immunocompetent apoE-deficient mice

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    Recombinant adenovirus (rAd)-mediated apoE gene transfer to the liver of apoE(-/-) mice is anti-atherogenic. However, first generation rAd vectors were associated with immune clearance of transduced hepatocytes, while an improved [E1(-), E3(-) polymerase(-)] adenovirus vector that persisted in the liver, had transient effects due to cellular shutdown of the cytomegalovirus (CMV) promoter (Ad-CMV-apoE). Here, we utilise an improved class of rAd vector with multiple deletions in the E1, E3, polymerase and pTP (pre-terminal protein) genes, which contains a modular synthetic liver-specific promoter (LSP) to drive expression of the human apoE cDNA (Ad-LSP-apoE) for hepatic gene transfer. Approximately 1 year old apoE(-/-) mice were injected intravenously with 4x10(10) virus particles of either Ad-LSP-apoE or Ad-CMV-apoE. Animals were monitored for plasma apoE, total plasma cholesterol and plasma lipoprotein distribution. The effect of Ad-LSP-apoE on atheroma progression was assessed in animals killed at 8 and 28 weeks after the injections. Ad-LSP-apoE vector administration gave sustained, though low, levels of plasma apoE throughout the study period without inducing a humoral immune response, but failed to reduce plasma cholesterol or normalize the adverse lipoprotein profile. Animals killed 8 weeks after the injections, demonstrated no significant retardation of atherosclerosis, whereas aortic lesions in those killed at 28 weeks were significantly reduced by 30% ( P< 0.006) compared to untreated animals. In summary, the combination of a multiply deleted rAd vector with a liver-specific promoter provided sustained low levels of plasma apoE, resulting in significant retardation of aortic atherosclerotic lesions

    Retardation of atherosclerosis in immunocompetent apolipoprotein (apo) E-deficient mice followingliver-directed administration of a [E1-, E3-,polymerase-] adenovirus vector containing the elongation factor-1a promoter driving expression of human apoE cDNA

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    Although gene transfer of human apolipoprotein E (apoE), a 34-kDa circulating glycoprotein, to the liver of apoEdeficient(apoE-/-) mice using recombinant adenoviral vectors (rAd) is antiatherogenic, its full therapeutic potentialhas yet to be realized. First generation vectors led to immune clearance of transduced hepatocytes, while animproved vector with adenovirus regions E1, E3 and DNA polymerase deleted also had transient effects due tocellular shutdown of the cytomegalovirus (CMV) promoter. Here, we have studied an alternative promoter from thecellular elongation factor 1a (EF-1a) gene, injecting 6-8 week old apoE-/- mice intravenously with 2x1010 virusparticles (vp) of the [E1-, E3-, polymerase-] rAd vector Ad-EF1·-apoE. Plasma apoE levels were low (18-55 ng/ml)and failed to reduce plasma cholesterol or normalize the adverse lipoprotein profile. By contrast, thehyperlipidaemic phenotype of apoE-/- mice treated with Ad-CMV-apoE (2x1010 vp) was transiently normalized.Nevertheless, at termination (265 days) the aortic lesion areas in animals given Ad-EF1·-apoE were significantlyreduced by 15% (P<0.05) compared to untreated animals, a decrease approaching that in Ad-CMV-apoE-treatedmice (23%; P<0.02). Importantly, the attenuation of apoE transgene expression noted with the CMV promoter wasabsent with the EF-1a promoter, which gave relatively sustained, albeit low, levels of plasma apoE throughout thestudy period

    Apolipoprotein E delivery by peritoneal implantation of encapsulated recombinant cells improves the hyperlipidaemic profile in apoE-deficient mice

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    Plasma apolipoprotein E (apoE) is a 34-kDa polymorphic protein which has atheroprotective actions by clearing remnant lipoproteins and sequestering excess cellular cholesterol. Low or dysfunctional apoE is a risk factor for hyperlipidaemia and atherosclerosis, and for restenosis after angioplasty. Here, in short-term studies designed to establish proof-of-principle, we investigate whether encapsulated recombinant Chinese hamster ovary (CHO) cells can secrete wild-type apoE3 protein in vitro and then determine whether peritoneal implantation of the microcapsules into apoE-deficient (apoE(-/-)) mice reduces their hypercholesterolaemia.Recombinant CHO-E3 cells were encapsulated into either alginate poly-L-lysine or alginate polyethyleneimine/polybrene microspheres. After verifying stability and apoE3 secretion, the beads were then implanted into the peritoneal cavity of apoE(-/-) mice; levels of plasma apoE3, cholesterol and lipoproteins were monitored for up to 14 days post-implantation.Encapsulated CHO-E3 cells continued to secrete apoE3 protein throughout a 60-day study period in vitro, though levels declined after 14 days. This cell-derived apoE3 was biologically active. When conditioned medium from encapsulated CHO-E3 cells was incubated with cultured cells pre-labelled with [H-3]-cholesterol, efflux of cholesterol was two to four times greater than with normal medium (at 8 h, for example, 7.4+/-0.3% vs. 2.4+/-0.2% of cellular cholesterol; P<0.001). Moreover, when secreted apoE3 was injected intraperitoneally into apoE(-/-) mice, apoE3 was detected in plasma and the hyperlipidaemia improved. Similarly, when alginate polyethyleneimine/polybrene capsules were implanted into the peritoneum of apoE(-/-) mice, apoE3 was secreted into plasma and at 7 days total cholesterol was reduced, while atheroprotective high-density lipoprotein (HDL) increased. In a second study, apoE was detectable in plasma of five mice treated with alginate poly-L-lysine beads, 4 and 7 days post-implantation, though not at day 14. Furthermore, their hypercholesterolaemia was reduced, while HDL was clearly elevated in all mice at days 4 and 7 (from 18.4+/-6.2% of total lipoproteins to 31.1+/-6.8% at 7 days; P<0.001); however, these had rebounded by day 14, possibly due to the emergence of anti-apoE antibodies.We conclude that microencapsulated apoE-secreting cells have the potential to ameliorate the hyperlipidaemia of apoE deficiency, but that the technology must be improved to become a feasible therapeutic to treat atherosclerosis. (C) 2004 Elsevier B.V. All rights reserved

    Cosmology with redshift surveys of radio sources

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    We use the K-z relation for radio galaxies to illustrate why it has proved difficult to obtain definitive cosmological results from studies based entirely on catalogues of the brightest radio sources, e.g. 3C. To improve on this situation we have been undertaking redshift surveys of complete samples drawn from the fainter 6C and 7C radio catalogues. We describe these surveys, and illustrate the new studies they are allowing. We also discuss our `filtered' 6C redshift surveys: these have led to the discovery of a radio galaxy at z=4.4, and are sensitive to similar objects at higher redshift provided the space density of these objects is not declining too rapidly with z. There is currently no direct evidence for a sharp decline in the space density of radio galaxies for z > 4, a result only barely consistent with the observed decline of flat-spectrum radio quasars.Comment: 8 pages Latex, To appear in the "Cosmology with the New Radio Surveys" Conference - Tenerife 13-15 January 199

    Do makerspaces represent scalable production models of community-based redistributed manufacturing?

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    This research explores the development of local community-based “makerspaces” as potential scalable forms of redistributed manufacturing (RDM). Makerspaces are rapidly emerging in post-industrial economies and have been identified as a catalyst of local regeneration in urban areas. However, their role in local production systems is limited. There is a gap in the literature, with respect to the evolution of makerspaces and their productive contribution. The purpose of this paper therefore is to identify, classify and examine the different types of makerspaces. Our focus is on the implementation characteristics that enable industrial production activity to take place. First, we used Leximancer (to identify from the literature) three types of makerspace. Second, we then identify five RDM implementation characteristics. The characteristics were integrated together to form the RDM-makerspace implementation model. Third, case studies were purposively selected to test and advance this model. They were subsequently classified as a Type 1 (educational), Type 2 (design) or Type 3 (production) makerspace. Only one of the case studies was classified as a fully evolved Type 3 production space. The findings concur with the literature that makerspaces tend to be primarily Type 1 or Type 2. Finally, the contribution to local production theory is emphasised

    Reliability and validity of the AGREE instrument used by physical therapists in assessment of clinical practice guidelines

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    BACKGROUND: The AGREE instrument has been validated for evaluating Clinical Practice Guidelines (CPG) pertaining to medical care. This study evaluated the reliability and validity of physical therapists using the AGREE to assess quality of CPGs relevant to physical therapy practice. METHODS: A total of 69 physical therapists participated and were classified as generalists, specialist or researchers. Pairs of appraisers within each category evaluated independently, a set of 6 CPG selected at random from a pool of 55 CPGs. RESULTS: Reliability between pairs of appraisers indicated low to high reliability depending on the domain and number of appraisers (0.17–0.81 for single appraiser; 0.30–0.96 when score averaged across a pair of appraisers). The highest reliability was achieved for Rigour of Development, which exceeded ICC> 0.79, if scores from pairs of appraisers were pooled. Adding more than 3 appraisers did not consistently improve reliability. Appraiser type did not determine reliability scores. End-users, including study participants and a separate sample of 102 physical therapy students, found the AGREE useful to guide critical appraisal. The construct validity of the AGREE was supported in that expected differences on Rigour of Development domains were observed between expert panels versus those with no/uncertain expertise (differences of 10–21% p = 0.09–0.001). Factor analysis with varimax rotation, produced a 4-factor solution that was similar, although not in exact agreement with the AGREE Domains. Validity was also supported by the correlation observed (Kendall-tao = 0.69) between Overall Assessment and the Rigour of Development domain. CONCLUSION: These findings suggest that the AGREE instrument is reliable and valid when used by physiotherapists to assess the quality of CPG pertaining to physical therapy health services

    Equality of Participation Online Versus Face to Face: Condensed Analysis of the Community Forum Deliberative Methods Demonstration

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    Online deliberation may provide a more cost-effective and/or less inhibiting environment for public participation than face to face (F2F). But do online methods bias participation toward certain individuals or groups? We compare F2F versus online participation in an experiment affording within-participants and cross-modal comparisons. For English speakers required to have Internet access as a condition of participation, we find no negative effects of online modes on equality of participation (EoP) related to gender, age, or educational level. Asynchronous online discussion appears to improve EoP for gender relative to F2F. Data suggest a dampening effect of online environments on black participants, as well as amplification for whites. Synchronous online voice communication EoP is on par with F2F across individuals. But individual-level EoP is much lower in the online forum, and greater online forum participation predicts greater F2F participation for individuals. Measured rates of participation are compared to self-reported experiences, and other findings are discussed.Comment: 14 pages, 10 tables, to appear in Efthimios Tambouris, Panos Panagiotopoulos, {\O}ystein S{\ae}b{\o}, Konstantinos Tarabanis, Michela Milano, Theresa Pardo, and Maria Wimmer (Editors), Electronic Participation: Proceedings of the 7th IFIP WG 8.5 International Conference, ePart 2015 (Thessaloniki, August 30-September 2), Springer LNCS Vol. 9249, 201

    The Viborg vascular (VIVA) screening trial of 65-74 year old men in the central region of Denmark: study protocol

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    <p>Abstract</p> <p>Background</p> <p>Screening for abdominal aortic aneurysm (AAA) of men aged 65-74 years reduces the AAA-related mortality and is generally considered cost effective. Despite of this only a few national health care services have implemented permanent programs.</p> <p>Around 10% of men in this group have peripheral arterial disease (PAD) defined by an ankle brachial systolic blood pressure index (ABI) below 0.9 resulting in an increased mortality-rate of 25-30%. In addition well-documented health benefits may be achieved through primary prophylaxis by initiating systematic cholesterol-lowering, smoking cessation, low-dose acetylsalicylic acid (aspirins), exercise, a healthy diet and blood-pressure control altogether reducing the increased risks for cardiovascular disease by at least 20-25%.</p> <p>The benefits of combining screening for AAA and PAD seem evident; yet they remain to be established. The objective of this study is to assess the efficacy and the cost-effectiveness of a combined screening program for AAA, PAD and hypertension.</p> <p>Methods</p> <p>The Viborg Vascular (VIVA) screening trial is a randomized, clinically controlled study designed to evaluate the benefits of vascular screening and modern vascular prophylaxis in a population of 50,000 men aged 65-74 years. Enrolment started October 2008 and is expected to stop in October 2010. The primary outcome is all-cause mortality. The secondary outcomes are cardiovascular mortality, AAA-related mortality, hospital services related to cardiovascular conditions, prevalence of AAA, PAD and potentially undiagnosed hypertension, health-related quality of life and cost effectiveness. Data analysis by intention to treat.</p> <p>Results</p> <p>Major follow-up will be performed at 3, 5 and 10 years and final study result after 15 years.</p> <p>Trial registration</p> <p>ClinicalTrials.gov NCT00662480</p
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