首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   90篇
  免费   41篇
  国内免费   9篇
耳鼻咽喉   3篇
妇产科学   1篇
基础医学   18篇
口腔科学   4篇
临床医学   39篇
内科学   7篇
神经病学   6篇
特种医学   2篇
外科学   39篇
综合类   12篇
预防医学   2篇
眼科学   5篇
中国医学   1篇
肿瘤学   1篇
  2023年   3篇
  2021年   5篇
  2020年   19篇
  2019年   18篇
  2018年   17篇
  2017年   9篇
  2016年   9篇
  2015年   10篇
  2014年   6篇
  2013年   11篇
  2012年   7篇
  2011年   6篇
  2010年   4篇
  2009年   5篇
  2008年   3篇
  2007年   4篇
  2006年   2篇
  2005年   1篇
  2003年   1篇
排序方式: 共有140条查询结果,搜索用时 15 毫秒
1.
The use of decellularized xenogeneic heart valves might offer a solution to overcome the issue of human valve shortage. The aim of this study was to revise decellularization protocols in combination with enzymatic deglycosylation, in order to reduce the immunogenicity of porcine pulmonary heart valves, in means of cells, carbohydrates, and, primarily, Galα1-3Gal (α-Gal) epitope removal. In particular, the valves were decellularized with sodium dodecylsulfate/sodium deoxycholate (SDS/SD), Triton X-100 + SDS (Tx + SDS), or Trypsin + Triton X-100 (Tryp + Tx) followed by enzymatic digestion with PNGaseF, Endoglycosidase H, or O-glycosidase combined with Neuraminidase. Results showed that decellularization alone reduced carbohydrate structures only to a limited extent, and it did not result in an α-Gal free scaffold. Nevertheless, decellularization with Tryp + Tx represented the most effective decellularization protocol in means of carbohydrates reduction. Overall, carbohydrates and α-Gal removal could strongly be improved by applying PNGaseF, in particular in combination with Tryp + Tx treatment, contrary to Endoglycosidase H and O-glycosidase treatments. Furthermore, decellularization with PNGaseF did not affect biomechanical stability, in comparison with decellularization alone, as shown by burst pressure and uniaxial tensile tests. In conclusion, valves decellularized with Tryp + Tx and PNGaseF resulted in prostheses with potentially reduced immunogenicity and maintained mechanical stability.  相似文献   
2.
Decellularized bovine pericardium (DBP)‐based biomeshes are the gold standard in reconstructive surgery. In order to prolong their stability after the transplantation, various chemical cross‐linking strategies are employed. However, structural and functional properties of the biomeshes differ in dependence on the cross‐linker used. Here, we performed a bottom‐up study of structural and functional alterations of DBP‐based biomeshes following cross‐linking with hexamethylene diisocyanate (HMDC), ethylene glycol diglycidyl ether (EGDE), 1‐ethyl‐3‐(3‐dimethylaminopropyl)carbodiimide (EDC) and genipin. The in vitro cytotoxicity tests supported their clinical applicability. Their structural differences (eg roughness, fibre thickness, pore morphology) were evaluated using the two‐photon confocal laser scanning, atomic force, scanning electron and polarized light microscopies. HMDC and EDC samples appeared to be the roughest. Complex mechanical trials indicated the tendency to reduced Young’s Modulus and mechanical anisotropy values of DBP upon cross‐linking. The lowest mechanical anisotropy was found in EDC and genipin sample groups. In vitro collagenase susceptibility was the highest for EDC samples and the lowest for EGDE samples. The comparative analysis of the results allowed us to recognize the strengths and weaknesses of each cross‐linker in relation to a particular clinical application.  相似文献   
3.
Tissue‐engineered heart valves aim to reproduce the biological properties of natural valves with anatomically correct structure and physiological performance. The closest alternative to creating an ideal heart valve substitute is to use decellularized porcine heart valves, due to their anatomy and availability. However, the immunological barrier and the structural maintenance limit the long‐term physiological performance of decellularized porcine heart valves. This study investigated the extracellular matrix (ECM) structure of aortic and pulmonary porcine valves decellularized by a low concentration sodium dodecyl sulfate (SDS)‐based method in order to determine the ECM scaffold (ECMS) conditions related to remodeling potential. To assess the structures of the leaflets and conduits of the heart valves, ECM components and their organization were evaluated by histology, biochemical analysis (BC), scanning electron microscopy, multiphoton microscopy, tensile test, immunofluorescence labeling (IF), and Raman microspectroscopy used to draw a profile of the cell niches. Histology and multiphoton imaging of decellularized aortic and pulmonary leaflets and conduits revealed a collagen and elastin histoarchitecture with rearrangement, loosening fibers, and glycosaminoglycan depletion confirmed by biochemistry quantification. The potential cytotoxicity of SDS residues was eliminated after 10 wash cycles. The mechanical properties of the structure of the valve indicated a functional resistance of decellularized ECM. The IF demonstrated the presence of basement membrane, suggesting a potential structure for host cell attachment. The RM analysis showed evidence of molecular interactions, suggesting conservation of the chemical composition, particularly among the protein molecular structures. The structural analyses performed in the semilunar porcine heart valves demonstrate that decellularized ECMS has structural properties that support physiological performance and potential host tissue integration. In fact, decellularized leaflet scaffolds were prone to cell interaction after human adipose‐derived stromal cell seeding and culturing. Further analysis of biocompatibility, particularly the ECM‐cell interaction, can elucidate the remodeling process, in preserved decellularized heart valve scaffold.  相似文献   
4.
Purpose: Despite a substantial amount of literature on tissue-guided regeneration, decellularization process, repopulation time points and stem cell turnover, more in-depth study on the argument is required. Currently, there are plenty of reports involving large animals, as well as clinical studies facing cardiac repair with decellularized homografts, but no exhaustive rodent models are described. The purpose of this study was to develop such a model in rats; preliminary results are also herein reported. Material and Methods: Fresh or decellularized pulmonary homografts from wild type rats were implanted in the abdominal aorta of green fluorescent protein positive rats. Three experimental groups were build up: sham, fresh homograft recipients and decellularized homograft recipients. The homograft decellularization process was performed with three cycles of detergent-enzymatic treatment protocol. Surgical technique of pulmonary homograft implantation and postoperative ultrasonographic evaluation were also reported; gross, histology and immunohistochemistry analysis on unimplanted and postoperative homografts were also carried out. Results: The median total recipient operating time was 148 minutes, with a surgical success rate of 82%. The decellularization protocol resulted effective and showed a complete decellularization with intact extracellular matrix. At 15 days from surgery, the implanted decellularized pulmonary homografts exhibited cell repopulation in the outer media wall and partial endothelial lining in absence of rejection. Conclusions: Our technique is a feasible and reproducible model that can be fundamental for building a valid study for further exploitation on the field. Even in a short-term follow up, the decellularized pulmonary homografts showed autologous repopulation in absence of rejection.  相似文献   
5.
6.
Heart tissue engineering holds a great potential for human heart disease therapy. Regeneration of whole biofunctional human heart is the ultimate goal of tissue engineering. Recent advances take the first step towards whole heart regeneration. However, a substantial amount of challenges have to be overcome.  相似文献   
7.
Tissue engineered tracheae have been successfully implanted to treat a small number of patients on compassionate grounds. The treatment has not become mainstream due to the time taken to produce the scaffold and the resultant financial costs. We have developed a method for decellularization (DC) based on vacuum technology, which when combined with an enzyme/detergent protocol significantly reduces the time required to create clinically suitable scaffolds. We have applied this technology to prepare porcine tracheal scaffolds and compared the results to scaffolds produced under normal atmospheric pressures. The principal outcome measures were the reduction in time (9 days to prepare the scaffold) followed by a reduction in residual DNA levels (DC no‐vac: 137.8±48.82 ng/mg vs. DC vac 36.83±18.45 ng/mg, p<0.05.). Our approach did not impact on the collagen or glycosaminoglycan content or on the biomechanical properties of the scaffolds. We applied the vacuum technology to human tracheae, which, when implanted in vivo showed no significant adverse immunological response. The addition of a vacuum to a conventional decellularization protocol significantly reduces production time, whilst providing a suitable scaffold. This increases clinical utility and lowers production costs. To our knowledge this is the first time that vacuum assisted decellularization has been explored. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   
8.
9.
Biologically derived scaffolds are becoming viable treatment options for tissue/organ repair and regeneration. A continuing hurdle is the need for a functional blood supply to and from the implanted scaffold. We have addressed this problem by constructing an acellular ileal scaffold with an attached vascular network suitable for implantation and immediate reperfusion with the host's blood. Using a vascular perfusion approach, a segment of porcine ileum up to 30 cm long, together with its attached vasculature, was decellularized as a single entity. The quality of the decellularized scaffold was assessed histologically and using molecular tools. To establish vascular perfusion potentials of the scaffold, a right‐sided nephrectomy and end‐to‐end anastomosis of the decellularized scaffold's vasculature to a renal artery and vein were performed in a pig of similar size to the donor animal. Lengths of ileal scaffold, together with its attached vasculature, were successfully decellularized, with no evidence of intact cells/nuclear material or collagen degradation. The scaffold's decellularized vascular network demonstrated optimum perfusion at 1, 2 and 24 h post‐implantation and the mesenteric arcade remained patent throughout the assessment. The 1, 2 and 24 h explanted scaffolds demonstrated signs of cellular attachment, with cells positive for CD68 and CD133 on the vascular luminal aspect. It is possible to decellularize clinically relevant lengths of small intestine, together with the associated vasculature, as a single segment. The functional vascular network may represent a route for recellularization for future regeneration of bowel tissue for patients with short bowel syndrome. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   
10.
Perfusion decellularization has been proposed as a promising method for generating nonimmunogenic organs from allogeneic or xenogeneic donors. Several imaging modalities have been used to assess vascular integrity in bioengineered organs with no consistency in the methodology used. Here, we studied the use of fluoroscopic angiography performed under controlled flow conditions for vascular integrity assessment in bioengineered kidneys. Porcine kidneys underwent ex vivo angiography before and after perfusion decellularization. Arterial and venous patencies were defined as visualization of contrast medium (CM) in distal capillaries and renal vein, respectively. Changes in vascular permeability were visualized and quantified. No differences in patency were detected in decellularized kidneys compared with native kidneys. However, focal parenchymal opacities and significant delay in CM clearance were detected in decellularized kidneys, indicating increased permeability. Biopsy-induced leakage was visualized in both groups, with digital subtraction angiography revealing minimal CM leakage earlier than nonsubtracted fluoroscopy. In summary, quantitative assessment of vascular permeability should be coupled with patency when studying the effect of perfusion decellularization on kidney vasculature. Flow-controlled angiography should be considered as the method of choice for vascular assessment in bioengineered kidneys. Adopting this methodology for organs premodified ex vivo under normothermic machine perfusion settings is also suggested.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号