263 research outputs found

    Osteogenic capacity of nanocrystalline bone cement in a weight-bearing defect at the ovine tibial metaphysis

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    The synthetic material Nanobone® (hydroxyapatite nanocrystallines embedded in a porous silica gel matrix) was examined in vivo using a standardized bone defect model in the ovine tibial metaphysis. A standardized 6 × 12 × 24-mm bone defect was created below the articular surface of the medial tibia condyles on both hind legs of 18 adult sheep. The defect on the right side was filled with Nanobone®, while the defect on the contralateral side was left empty. The tibial heads of six sheep were analyzed after 6, 12, and 26 weeks each. The histological and radiological analysis of the defect on the control side did not reveal any bone formation after the total of 26 weeks. In contrast, the microcomputed tomography analysis of the defect filled with Nanobone® showed a 55%, 72%, and 74% volume fraction of structures with bone density after 6, 12, and 26 weeks, respectively. Quantitative histomorphological analysis after 6, and 12 weeks revealed an osteoneogenesis of 22%, and 36%, respectively. Hematoxylin and eosin sections demonstrated multinucleated giant cells on the surface of the biomaterial and resorption lacunae, indicating osteoclastic resorptive activity. Nanobone® appears to be a highly potent bone substitute material with osteoconductive properties in a loaded large animal defect model, supporting the potential use of Nanobone® also in humans

    Dose-related beneficial long-term hemodynamic and clinical efficacy of irbesartan in heart failure

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    AbstractOBJECTIVESThe primary purpose of this study was to determine the acute and long-term hemodynamic and clinical effects of irbesartan in patients with heart failure.BACKGROUNDInhibition of angiotensin II production by angiotensin-converting enzyme (ACE) inhibitors reduces morbidity and mortality in patients with heart failure. Irbesartan is an orally active antagonist of the angiotensin II AT1receptor subtype with potential efficacy in heart failure.METHODSTwo hundred eighteen patients with symptomatic heart failure (New York Heart Association [NYHA] class II–IV) and left ventricular ejection fraction ≤40% participated in the study. Serial hemodynamic measurements were made over 24 h following randomization to irbesartan 12.5 mg, 37.5 mg, 75 mg, 150 mg or placebo. After the first dose of study medication, patients receiving placebo were reallocated to one of the four irbesartan doses, treatment was continued for 12 weeks and hemodynamic measurements were repeated.RESULTSIrbesartan induced significant dose-related decreases in pulmonary capillary wedge pressure (average change −5.9 ± 0.9 mm Hg and −5.3 ± 0.9 mm Hg for irbesartan 75 mg and 150 mg, respectively) after 12 weeks of therapy without causing reflex tachycardia and without increasing plasma norepinephrine. The neurohormonal effects of irbesartan were highly variable and none of the changes was statistically significant. There was a significant dose-related decrease in the percentage of patients discontinuing study medication because of worsening heart failure. Irbesartan was well tolerated without evidence of dose-related cough or azotemia.CONCLUSIONSIrbesartan, at once-daily doses of 75 mg and 150 mg, induced sustained hemodynamic improvement and prevented worsening heart failure

    Aetiology of community-acquired, acute gastroenteritis in hospitalised adults: a prospective cohort study

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    <p>Abstract</p> <p>Background</p> <p>The aetiology of severe gastroenteritis leading to hospitalisation in adults frequently remains unclear. Our objective was to study the causes and characteristics of community-acquired, acute gastroenteritis in adult hospitalized patients to support the clinical management of these patients.</p> <p>Methods</p> <p>From August 2005 to August 2007, we conducted a prospective cohort study among patients ≥18 y hospitalized with community-acquired gastroenteritis in a university hospital in Berlin, Germany. Stool specimens were examined for 26 gastrointestinal pathogens, supplemented by serologic tests for antibodies to <it>Campylobacter spp.</it>, <it>Yersinia spp.</it>, and <it>Entamoeba histolytica</it>. Patient data on demographics and clinical presentation were recorded and analyzed. Coexisting medical conditions were assessed using the Charlson Comorbidity Index score.</p> <p>Results</p> <p>Of 132 patients presenting with acute community-acquired gastroenteritis, 104 were included in the study. A non-infectious aetiology was diagnosed in 8 patients (8%). In 79 (82%) of the remaining 96 patients at least one microorganism was identified. <it>Campylobacter spp. </it>(35%) was detected most frequently, followed by norovirus (23%), <it>Salmonella spp. </it>(20%), and rotavirus (15%). In 46% of the patients with <it>Campylobacter spp. </it>infection, the diagnosis was made solely by serology. More than one pathogen was found in seventeen (22%) patients. Simultaneous infection was significantly more likely in patients with rotavirus and salmonella infections (RR 3.6; 95% CI: 1.8–7.4; RR 2.5; 95%CI: 1.2–5.5). Length of hospital stay (median: 5.5 days) was independent of the pathogen, but was associated with coexisting medical conditions (OR 4,8; 95%CI:2,0–11,6).</p> <p>Conclusion</p> <p>Known enteric pathogens were detected in 82% of adult patients who were hospitalized with acute gastroenteritis. We found that currently used culture-based methods may miss a substantial proportion of <it>Campylobacter </it>infections, and additional serological testing for <it>Campylobacter </it>should be considered. Viral infections emerged as an important cause of severe gastroenteritis in adults, and viral-bacterial co-infections in adults are probably underrecognized so far. The presence of coexisting medical conditions – but not the etiological agent – was a predictor for the duration of the hospital stay.</p

    Magnetohydrodynamics of the Early Universe and the Evolution of Primordial Magnetic Fields

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    We show that the decaying magnetohydrodynamic turbulence leads to a more rapid growth of the correlation length of a primordial magnetic field than that caused by the expansion of the Universe. As an example, we consider the magnetic fields created during the electroweak phase transition. The expansion of the universe alone would yield a correlation length at the present epoch of 1 AU, whereas we find that the correlation length is likely of order 100 AU, and cannot possibly be longer than 10410^4 AU for non-helical fields. If the primordial field is strongly helical, the correlation length can be much larger, but we show that even in this case it cannot exceed 100 pc. All these estimates make it hard to believe that the observed galactic magnetic fields can result from the amplification of seed fields generated at the electroweak phase transition by the standard galactic dynamo.Comment: 15 pages, REVTeX. Added results of numerical simulation, enlarged and revise

    Ciclo vital del pulpo marmóreo, Amphioctopus aegina (Gray) (Cephalopoda: Octopodidae) criado en laboratorio

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    Reproducing small eggs and planktonic hatchlings is a reproductive strategy of many species of benthic octopods although it is considered a pleisiomorphic state. The young in the planktonic and settling phases have a high energy consumption and require live food of specific size range characteristics, causing difficulties in obtaining appropriate food organisms for rearing experiments through the entire life cycle. This study obtained information on details of life cycle characteristics of Amphioctopus aegina (Gray) by resolving these difficulties. The aspects of life cycle of A. aegina were similar to those of other benthic octopus with a similar reproductive strategy. Growth was allometric, consisting of 3 phases in terms of body weight, including a transitional phase for the early settling stage. Feeding and conversion efficiency peaked over a 2-month period prior to reproduction, representing the period of energy storage. Growth from hatching to spawning took approximately 74% of the entire life span and the reproductive phase itself took 34%. Such longevities are similar to those of other benthic cephalopods with planktonic hatchlings. Overall similarities in these cephalopod taxa attest to the fitness of a life-history strategy involving production of planktonic offspring from benthic adults. A. aegina is the second benthic octopus species with planktonic hatchlings for which the life cycle has been completed through rearing in the laboratory.El desove de pequeños huevos que darán origen a plancton constituye la estrategia de reproducción de numerosos octópodos bénticos, aunque se asocia a un estado plesiomórfico. Las nuevas criaturas en fase planctónica y de asentamiento requieren un gran consumo energético y nutrientes vivos con características y dimensiones específicas, lo que dificulta la obtención de organismos que les sirvan de alimento a lo largo de todo el ciclo vital. A partir de este estudio se han obtenido datos sobre las características del ciclo vital del Amphioctopus aegina (Gray) mediante la resolución de estas dificultades. Muchos aspectos del ciclo vital del A. aegina resultaron muy similares a los de otros pulpos bénticos con una estrategia de reproducción parecida. Se produjo un crecimiento alométrico en tres fases, según el peso corporal, que incluía una fase de transición en el periodo de asentamiento inicial. La eficacia en la alimentación y la conversión alcanzó su punto máximo en los 2 meses previos a la reproducción, que representan un periodo de almacenamiento energético. El crecimiento desde la eclosión hasta el desove fue aproximadamente el 74% del ciclo vital completo, y la fase reproductiva en sí supuso un 34%. Tal longevidad es compartida por otros cefalópodos bénticos con desoves planctónicos. Las similitudes generales entre estas categorías taxonómicas de cefalópodos confirman el éxito de esta estrategia de ciclos vitales en la producción de crías planctónicas por parte de adultos bénticos. A. aegina es la segunda especie de pulpo béntico con desove planctónico cuyo ciclo vital ha logrado completarse mediante la cría en laboratorio

    Remote Sensing of Antarctic Sea Ice with Coordinated Aircraft and Satellite Data Acquisitions

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    Remote sensing of Antarctic sea ice is required to characterize properties of the vast sea ice cover to understand its long-term increase in contrast to the decrease of Arctic sea ice. For this objective, the OIB/TanDEM-X Coordinated Science Campaign (OTASC) was successfully conducted in 2017 to obtain contemporaneous and collocated remote sensing data from NASA's Operation IceBridge (OIB) and the German Aerospace Center (DLR) TanDEM-X Synthetic Aperture Radar (SAR) system at X-band together with Sentinel-1 and RADARSAT-2 SARs at C-band in conjunction with WorldView satellite spectral sensors, surface measurements, and field observations. The Weddell Sea and the Ross Sea were two primary regions while SAR data were also collected over six other regions in the Southern Ocean. Satellite SAR data included both polarimetric and interferometric capabilities to infer snow and sea ice information in three dimensions (3D), while OIB/P-3 aircraft data include snow radar together with altimeter data for snow and sea ice observations in 3D over the Weddell Sea. Across the Ross Sea, IcePOD and AntNZ/York-University flights were carried out together with satellite SAR data acquisitions

    Additive Value of Preprocedural Computed Tomography Planning Versus Stand-Alone Transesophageal Echocardiogram Guidance to Left Atrial Appendage Occlusion: Comparison of Real-World Practice

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    Background: Transesophageal echocardiogram is currently the standard preprocedural imaging for left atrial appendage occlusion. This study aimed to assess the additive value of preprocedural computed tomography (CT) planning versus stand-alone transesophageal echocardiogram imaging guidance to left atrial appendage occlusion. Methods and Results: We retrospectively reviewed 485 Watchman implantations at a single center to compare the outcomes of using additional CT preprocedural planning (n=328, 67.6%) versus stand-alone transesophageal echocardiogram guidance (n=157, 32.4%) for left atrial appendage occlusion. The primary end point was the rate of successful device implantation without major peri-device leak (\u3e5 mm). Secondary end points included major adverse events, total procedural time, delivery sheath and devices used, risk of major peri-device leak and device-related thrombus at follow-up imaging. A single/anterior-curve delivery sheath was used more commonly in those who underwent CT imaging (35.9% versus 18.8%; P\u3c0.001). Additional preprocedural CT planning was associated with a significantly higher successful device implantation rate (98.5% versus 94.9%; P=0.02), a shorter procedural time (median, 45.5 minutes versus 51.0 minutes; P=0.03) and a less frequent change of device size (5.6% versus 12.1%; P=0.01), particularly device upsize (4% versus 9.4%; P=0.02). However, there was no significant difference in the risk of major adverse events (2.1% versus 1.9%; P=0.87). Only 1 significant peri-device leak (0.2%) and 5 device-related thrombi were detected in follow-up (1.2%) with no intergroup difference. Conclusions: Additional preprocedural planning using CT in Watchman implantation was associated with a higher successful device implantation rate, a shorter total procedural time, and a less frequent change of device sizes
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