295 research outputs found

    One-hundred aortic valve replacements in octogenarians: Outcomes and risk factors for early mortality

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    Background and aim of the study: Today, ageing of the western population is causing aortic valve surgery to be performed in elderly patients with increasing frequency. The study aim was to evaluate surgical outcome in octogenarian patients undergoing aortic valve replacement (AVR). Methods: A total of 100 patients (mean age 82.1 +/- 2.7 years; range: 80-95 years) who underwent AVR over a three-year period was reviewed. Concomitant coronary artery bypass grafting was performed in 34% of cases, and a bioprosthesis was implanted in 80%. The mean logistic EuroSCORE was 13.3%. Results: Operative mortality was 8.0%. In multivariate analysis, a logistic EuroSCORE >= 13.5% (p = 0.02), cross-clamp time >= 75 min (p = 0.02) and postoperative acute renal failure were predictors for in-hospital mortality. Follow up was 100% complete; the mean follow up period was 10.6 months. At one year after surgery, the actuarial survival rate of those patients who survived surgery was 86.1%. Postoperative dyspnea at one month (p = 0.004) was the only predictor of short-term mortality. Conclusion: Age in itself should not contraindicate surgery, and healthcare systems should be prepared to accommodate elderly patients who may require special resources

    Video-assisted mitral surgery through a micro-access: A safe and reliable reality in the current era

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    Background and aim of the study: Minimally invasive mitral valve surgery was introduced into clinical practice during the mid 1990s. The clinical benefits of the technique, namely a reduction of surgical trauma, increased patient comfort and shorter hospital stay, are achieved by using a video-assisted, mini-thoracotomy approach rather than a standard median sternotomy. Herein is described the authors' experience with video-assisted mitral surgery through a micro-access. Methods: Between September 2003 and September 2006, 100 patients (mean age 65.7 years; range: 16-84 years; 29 aged >75 years) underwent video-assisted port-access mitral valve surgery through a 4- to 6-cm anterior mini-thoracotomy. Mitral valve repair was carried out in 36 patients (36%) and mitral valve replacement (MVR) in 64 (64%) for degenerative (n = 54), rheumatic (n = 44), functional (n = 1) or infective disease (n = 1). Redo procedures were performed in 14 patients. Results: Peripheral extra-thoracic cardiopulmonary bypass (CPB) was used in all cases, and Endoclamp occlusion of the ascending aorta in 94%. The median intensive care unit and hospital stays were 20.0 +/- 30.8 h and 7.0 +/- 5.9 days, respectively. Hospital mortality was 4% (n = 4). No patient required conversion to sternotomy. Five patients (5%) underwent minimally invasive surgical revision for bleeding, and one patient (1%) had an early reoperation for MVR during the immediate postoperative course due to failure of a mitral valve repair. There were no perioperative myocardial infarctions, permanent strokes, major vascular complications, or peripheral ischemic events. Among the patients, 63% had no complications at all during the postoperative course, and no wound infections were observed. Conclusion: Video-assisted mitral surgery through a micro-access may be performed safely, at low risk of morbidity and mortality, and with results and quality standards similar to those reported for a sternotomy approach. Of note, older patients may be successfully treated using this technique

    Radioligand therapy (RLT) as neoadjuvant treatment for inoperable pancreatic neuroendocrine tumors: a literature review

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    In the last 10 years, several literature reports supported radioligand therapy (RLT) in neoadjuvant settings for pancreatic neuroendocrine tumors (PanNETs). Indeed, primary tumor shrinkage has been frequently reported following RLT in unresectable or borderline resectable PanNETs. Moreover, RLT-induced intratumoral modifications facilitate surgery, both on primary tumor and metastasis, having a great impact on progression free survival (PFS), overall survival (OS) and quality of life (QoL). However, prospective controlled investigations are necessary to confirm preliminary data and to define the best RLT scheme and the ideal patient that, in a multidisciplinary approach, should be referred to neoadjuvant RLT

    The edge-on protoplanetary disk HH 48 NE I. Modeling the geometry and stellar parameters

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    Context. Observations of edge-on disks are an important tool for constraining general protoplanetary disk properties that cannot be determined in any other way. However, most radiative transfer models cannot simultaneously reproduce the spectral energy distributions (SEDs) and resolved scattered light and submillimeter observations of these systems, due to the differences in geometry and dust properties at different wavelengths. Aims. We simultaneously constrain the geometry of the edge-on protoplanetary disk HH 48 NE and the characteristics of the host star. HH 48 NE is part of the JWST early release science program Ice Age. This work serves as a stepping stone towards a better understanding of the disk physical structure and icy chemistry in this particular source. This kind of modeling lays the groundwork for studying other edge-on sources to be observed with the JWST. Methods. We fit a parameterized dust model to HH 48 NE by coupling the radiative transfer code RADMC-3D and an MCMC framework. The dust structure was fitted independently to a compiled SED, a scattered light image at 0.8 μ{\mu}m and an ALMA dust continuum observation at 890 μ{\mu}m. Results. We find that 90% of the dust mass in HH 48 NE is settled to the disk midplane, less than in average disks, and that the atmospheric layers of the disk contain exclusively large grains (0.3-10 μ{\mu}m). The exclusion of small grains in the upper atmosphere likely has important consequences for the chemistry due to the deep penetration of high-energy photons. The addition of a relatively large cavity (ca. 50 au in radius) is necessary to explain the strong mid-infrared emission, and to fit the scattered light and continuum observations simultaneously.Comment: 16 pages, 8 figures, accepted for publication in Astronomy & Astrophysic

    NEMO: A Project for a km3^3 Underwater Detector for Astrophysical Neutrinos in the Mediterranean Sea

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    The status of the project is described: the activity on long term characterization of water optical and oceanographic parameters at the Capo Passero site candidate for the Mediterranean km3^3 neutrino telescope; the feasibility study; the physics performances and underwater technology for the km3^3; the activity on NEMO Phase 1, a technological demonstrator that has been deployed at 2000 m depth 25 km offshore Catania; the realization of an underwater infrastructure at 3500 m depth at the candidate site (NEMO Phase 2).Comment: Proceeding of ISCRA 2006, Erice 20-27 June 200

    Measurement of the atmospheric muon flux with the NEMO Phase-1 detector

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    The NEMO Collaboration installed and operated an underwater detector including prototypes of the critical elements of a possible underwater km3 neutrino telescope: a four-floor tower (called Mini-Tower) and a Junction Box. The detector was developed to test some of the main systems of the km3 detector, including the data transmission, the power distribution, the timing calibration and the acoustic positioning systems as well as to verify the capabilities of a single tridimensional detection structure to reconstruct muon tracks. We present results of the analysis of the data collected with the NEMO Mini-Tower. The position of photomultiplier tubes (PMTs) is determined through the acoustic position system. Signals detected with PMTs are used to reconstruct the tracks of atmospheric muons. The angular distribution of atmospheric muons was measured and results compared with Monte Carlo simulations.Comment: Astrop. Phys., accepte

    Synchronization in G0/G1 enhances the mitogenic response of cells overexpressing the human insulin receptor A isoform to insulin

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    Evaluating mitogenic signaling specifically through the human insulin receptor (IR) is relevant for the preclinical safety assessment of developmental insulin analogs. It is known that overexpression of IR sensitizes cells to the mitogenic effects of insulin, but it is essentially unknown how mitogenic responses can be optimized to allow practical use of such recombinant cell lines for preclinical safety testing. We constitutively overexpressed the short isoform of the human insulin receptor (hIR-A, exon 11-negative) in L6 rat skeletal myoblasts. Because the mitogenic effect of growth factors such as insulin is expected to act in G0/G1, promoting S-phase entry, we developed a combined topoinhibition + serum deprivation strategy to explore the effect of G0/G1 synchronization as an independent parameter in the context of serum deprivation, the latter being routinely used to reduce background in mitogenicity assays. G0/G1 synchronization significantly improved the mitogenic responses of L6-hIR cells to insulin, measured by 3H-thymidine incorporation. Comparison with the parental L6 cells using phospho-mitogen-activated protein kinase, phospho-AKT, as well as 3H-thymidine incorporation end points supported that the majority of the mitogenic effect of insulin in L6-hIR cells was mediated by the overexpressed hIR-A. Using the optimized L6-hIR assay, we found that the X-10 insulin analog was more mitogenic than native human insulin, supporting that X-10 exhibits increased mitogenic signaling through the hIR-A. In summary, this study provides the first demonstration that serum deprivation may not be sufficient, and G0/G1 synchronization may be required to obtain optimal responsiveness of hIR-overexpressing cell lines for preclinical safety testing

    Bio-psychosocial determinants of time lost from work following non life threatening acute orthopaedic trauma

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    <p>Abstract</p> <p>Background</p> <p>To determine factors predicting the duration of time away from work following acute orthopaedic non life threatening trauma</p> <p>Methods</p> <p>Prospective cohort study conducted at four hospitals in Victoria, Australia. The cohort comprised 168 patients aged 18-64 years who were working prior to the injury and sustained a range of acute unintentional orthopaedic injuries resulting in hospitalization. Baseline data was obtained by survey and medical record review. Multivariate Cox proportional hazards regression analysis was used to examine the association between potential predictors and the duration of time away from work during the six month study. The study achieved 89% follow-up.</p> <p>Results</p> <p>Of the 168 participants recruited to the study, 68% returned to work during the six month study. Multivariate Cox proportional hazards regression analysis identified that blue collar work, negative pain attitudes with respect to work, high initial pain intensity, injury severity, older age, initial need for surgery, the presence of co-morbid health conditions at study entry and an orthopaedic injury to more than one region were associated with extended duration away from work following the injury. Participants in receipt of compensation who reported high social functioning at two weeks were 2.58 times more likely to have returned to work than similar participants reporting low social functioning. When only those who had returned to work were considered, the participant reported reason for return to work " to fill the day" was a significant predictor of earlier RTW [RR 2.41 (95% C.I 1.35-4.30)] whereas "financial security" and "because they felt able to" did not achieve significance.</p> <p>Conclusions</p> <p>Many injury-related and psycho social factors affect the duration of time away from work following orthopaedic injury. Some of these are potentially modifiable and may be amenable to intervention. Further consideration of the reasons provided by participants for returning to work may provide important opportunities for social marketing approaches designed to alleviate the financial and social burden associated with work disability.</p

    Inactivation of class II PI3K-C2 alpha induces leptin resistance, age-dependent insulin resistance and obesity in male mice

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    AIMS/HYPOTHESIS: While the class I phosphoinositide 3-kinases (PI3Ks) are well-documented positive regulators of metabolism, the involvement of class II PI3K isoforms (PI3K-C2α, -C2β and -C2γ) in metabolic regulation is just emerging. Organismal inactivation of PI3K-C2β increases insulin signalling and sensitivity, whereas PI3K-C2γ inactivation has a negative metabolic impact. In contrast, the role of PI3K-C2α in organismal metabolism remains unexplored. In this study, we investigated whether kinase inactivation of PI3K-C2α affects glucose metabolism in mice. METHODS: We have generated and characterised a mouse line with a constitutive inactivating knock-in (KI) mutation in the kinase domain of the gene encoding PI3K-C2α (Pik3c2a). RESULTS: While homozygosity for kinase-dead PI3K-C2α was embryonic lethal, heterozygous PI3K-C2α KI mice were viable and fertile, with no significant histopathological findings. However, male heterozygous mice showed early onset leptin resistance, with a defect in leptin signalling in the hypothalamus, correlating with a mild, age-dependent obesity, insulin resistance and glucose intolerance. Insulin signalling was unaffected in insulin target tissues of PI3K-C2α KI mice, in contrast to previous reports in which downregulation of PI3K-C2α in cell lines was shown to dampen insulin signalling. Interestingly, no metabolic phenotypes were detected in female PI3K-C2α KI mice at any age. CONCLUSIONS/INTERPRETATION: Our data uncover a sex-dependent role for PI3K-C2α in the modulation of hypothalamic leptin action and systemic glucose homeostasis. ACCESS TO RESEARCH MATERIALS: All reagents are available upon request
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