98 resultados para graft hybridization
em BORIS: Bern Open Repository and Information System - Berna - Suiça
Resumo:
The use of radial artery conduits in coronary artery bypass grafting (CABG) surgery is associated with improved long-term patency and patient survival rates as compared with saphenous vein conduits. Despite increasing popularity, relative incidence of local harvest-site complications and subjective perception of adverse long-term sequelae remain poorly described.
Resumo:
The study aims to identify risk constellations for symptomatic spinal cord malperfusion in patients undergoing extensive stent-graft coverage of the thoracic aorta.
Resumo:
The objective of the study was to determine the feasibility of generating a biodegradable, stem cell-loaded osteogenic composite graft from human placenta. Initially, a scaffold from human chorion membrane was produced. Human placenta mesenchymal stem cells (MSCs) derived from either first-trimester chorionic villi or term chorion membrane were differentiated osteogenically on this scaffold. Outgrowth, adherence, and osteogenic differentiation of cells were assessed by immunohistochemistry (IHC), scanning electron microscopy, protein expression, and real-time polymerase chain reaction (RT-PCR). Our results showed that a cell-free extracellular matrix scaffold can be generated from human chorion. Seeded MSCs densely adhered to that scaffold and were osteogenically differentiated. Calcium and alkaline phosphatase were detected in the cell-scaffold constructs as a proof of mineralization and findings were confirmed by IHC and RT-PCR results. This study shows for the first time that generation of an osteogenic composite graft using placental tissue is feasible. It might allow therapeutic application of autologous or allogeneic grafts in congenital skeletal defects by means of a composite graft.
Resumo:
Whitefish, genus Coregonus, show exceptional levels of phenotypic diversity with sympatric morphs occurring in numerous postglacial lakes in the northern hemisphere. Here, we studied the effects of human-induced eutrophication on sympatric whitefish morphs in the Swiss lake, Lake Thun. In particular, we addressed the questions whether eutrophication (i) induced hybridization between two ecologically divergent summer-spawning morphs through a loss of environmental heterogeneity, and (ii) induced rapid adaptive morphological changes through changes in the food web structure. Genetic analysis based on 11 microsatellite loci of 282 spawners revealed that the pelagic and the benthic morph represent highly distinct gene pools occurring at different relative proportions on all seven known spawning sites. Gill raker counts, a highly heritable trait, showed nearly discrete distributions for the two morphs. Multilocus genotypes characteristic of the pelagic morph had more gill rakers than genotypes characteristic of benthic morph. Using Bayesian methods, we found indications of recent but limited introgressive hybridization. Comparisons with historical gill raker data yielded median evolutionary rates of 0.24 haldanes and median selection intensities of 0.27 for this trait in both morphs for 1948-2004 suggesting rapid evolution through directional selection at this trait. However, phenotypic plasticity as an alternative explanation for this phenotypic change cannot be discarded. We hypothesize that both the temporal shifts in mean gill raker counts and the recent hybridization reflect responses to changes in the trophic state of the lake induced by pollution in the 1960s, which created novel selection pressures with respect to feeding niches and spawning site preferences.
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To investigate the technical feasibility of harvesting a vascularized bone graft from the acromion pedicled on the acromial branch.
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The three-spined stickleback is a widespread Holarctic species complex that radiated from the sea into freshwaters after the retreat of the Pleistocene ice sheets. In Switzerland, sticklebacks were absent with the exception of the far northwest, but different introduced populations have expanded to occupy a wide range of habitats since the late 19th century. A well-studied adaptive phenotypic trait in sticklebacks is the number of lateral plates. With few exceptions, freshwater and marine populations in Europe are fixed for either the low plated phenotype or the fully plated phenotype, respectively. Switzerland, in contrast, harbours in close proximity the full range of phenotypic variation known from across the continent. We addressed the phylogeographic origins of Swiss sticklebacks using mitochondrial partial cytochrome b and control region sequences. We found only five different haplotypes but these originated from three distinct European regions, fixed for different plate phenotypes. These lineages occur largely in isolation at opposite ends of Switzerland, but co-occur in a large central part. Across the country, we found a strong correlation between a microsatellite linked to the high plate ectodysplasin allele and the mitochondrial haplotype from a region where the fully plated phenotype is fixed. Phylogenomic and population genomic analysis of 481 polymorphic amplified fragment length polymorphism loci indicate genetic admixture in the central part of the country. The same part of the country also carries elevated within-population phenotypic variation. We conclude that during the recent invasive range expansion of sticklebacks in Switzerland, adaptive and neutral between-population genetic variation was converted into within-population variation, raising the possibility that hybridization between colonizing lineages contributed to the ecological success of sticklebacks in Switzerland.
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Reconstruction of the right ventricular outflow tract plays a major role in congenital cardiac surgery. With the advent of the Contegra bovine jugular vein graft and the Shelhigh pulmonic xenograft, hopes were high that the lack of availability of homografts would be overcome. The present study evaluated both grafts and investigated the influence of known risk factors for premature graft failure.
Resumo:
The aim of this study was to evaluate a new surgical concept for the treatment of graft infections after operation or endovascular treatment of thoracic, thoracoabdominal, and abdominal aortic diseases.
Resumo:
Thoracic endovascular aortic repair (TEVAR) has emerged as a promising therapeutic alternative to conventional open aortic replacement but it requires suitable proximal and distal landing zones for stent-graft anchoring. Many aortic pathologies affect in the immediate proximity of the left subclavian artery (LSA) limiting the proximal landing zone site without proximal vessel coverage. In patients in whom the distance between the LSA and aortic lesion is too short, extension of the landing zone can be obtained by covering the LSA's origin with the endovascular stent graft (ESG). This manoeuvre has the potential for immediate and delayed neurological and vascular symptoms. Some authors, therefore, propose prophylactic revascularisation of the LSA by transposition or bypass, while others suggest prophylactic revascularisation only under certain conditions, and still others see no requirement for prophylactic revascularisation in anticipation of LSA ostium coverage. In this review about LSA revascularisation in TEVAR patients with coverage of the LSA, we searched the electronic databases MEDLINE and EMBASE historically until the end date of May 2010 with the search terms left subclavian artery, covering, endovascular, revascularisation and thoracic aorta. We have gathered the most complete scientific evidence available used to support the various concepts to deal with this issue. After a review of the current available literature, 23 relevant articles were found, where we have identified and analysed three basic treatment concepts for LSA revascularisation in TEVAR patients (prophylactic, conditional prophylactic and no prophylactic LSA revascularisation). The available evidence supports prophylactic revascularisation of the LSA before ESG LSA coverage when preoperative imaging reveals abnormal supra-aortic vascular anatomy or pathology. We further conclude that elective patients undergoing planned coverage of the LSA during TEVAR should receive prophylactic LSA transposition or LSA-to-left-common-carotid-artery (LCCA) bypass surgery to prevent severe neurological complications, such as paraplegia or brain stem infarction.
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Endovascular aneurysm repair (EVAR) is associated with high graft-related complication rates during follow-up. Anatomical fit between patient and endograft could be an important factor for successful treatment. Aim was to assess whether extent of thrombus, calcification, angulation, and tortuosity are associated with occurrence of complications after EVAR.