碳质股骨头生物相容性的动物实验*★

背景：已有大量的临床和体外实验研究表明，低温热解各向同性碳具有优良的生物学性能，但作为人工关节假体涂层，置入髋关节内的研究还鲜见报道，其在人工半髋关节假体置换中的生物学性能还没有得到验证。 目的：通过动物假体置入实验，观察经低温热解各向同性碳(含硅)喷涂后碳质股骨头假体的组织相容性及表面摩擦磨损特性。 设计、时间及地点：动物体内进行碳质人工半髋关节替换，随机对照动物实验，于2008-10/2009-04在解放军第二军医大学动物实验中心完成。 材料：碳质人工半髋关节由吉林市中心医院提供。股骨头以碳石墨材料为基体，沉积含硅的低温热解各向同性碳为涂层。 方法：对16只成年新西兰大白兔进行右侧半髋关节置换术，置入碳质股骨头假体。按照观察时间点随机分为术后6周组4只，术后11周组6只，术后21周组6只，其中21周组从18周开始在动物实验中心草坪上进行诱导性运动，2 h/d。 主要观察指标：通过大体、X射线片、组织切片观察假体置入后的组织相容性及界面摩擦磨损现象。 结果：碳质股骨头假体在动物体内无毒副作用，无明显炎症反应和异物反应，在碳质假体周围发现有新生软骨组织，运动实验后碳质股骨头表面没有明显磨损和碳颗粒游离现象。 结论：涂膜碳质材料作为人工股骨头具有优良的生物相容性和耐磨特能，是一种极具应用前景的人工假体材料。 关键词：碳质股骨头；人工髋关节；生物相容性；新生软骨；磨损     

Biocompatibility of acellular human pericardium

BACKGROUND: Previous studies have shown successful decellularization of human pericardium without affecting the major structural components and strength of the matrix. The aim of this study was to assess the biocompatibility and reseeding potential of the acellular human pericardial scaffold. MATERIALS AND METHODS: Pericardia were treated sequentially with hypotonic buffer, sodium dodecyl sulfate, and a nuclease solution. The presence of cellular attachment factors after decellularization was evaluated using immunohistochemistry. The scaffold was seeded with dermal fibroblasts and cellular attachment to and numbers of cells penetrating were assessed over time. Biocompatibility was also evaluated following subcutaneous implantation into a mouse model for three months. RESULTS: After decellularization, the scaffold stained positively for fibronectin, but collagen IV and laminin staining was reduced. Seeded fibroblasts attached to the mesothelial surface and were visualized in the tissue within a week of seeding. The majority of fibroblasts in the tissue were viable and there was evidence of remodeling of the matrix. Analysis of the explanted tissues from mice showed that fresh/frozen and glutaraldehyde-fixed pericardia were encapsulated with a thick layer of inflammatory cells and fibrous tissue. In contrast, the decellularized scaffold was infiltrated with myofibroblasts, CD34+ cells and macrophages, indicating a healthy repair process. Compared with the glutaraldehyde-fixed tissue, the calcium content of the fresh/frozen and decellularized pericardia was negligible. CONCLUSIONS: The pericardial scaffold was biocompatible in vitro and in the mouse model in vivo.     

新型内插销式桩核冠应用于咬合过紧患者残根修复的临床研究

目的:评价新型内插销式桩核冠应用于深覆伴重度牙体缺损患者的修复疗效。方法:随机选择深覆患者36颗磨牙残冠,采用新型内插销式桩核冠固定义齿修复经过4年临床随访,观察其在深覆伴重度牙体缺损患者的应用效果。结果:新型内插销式桩核冠固定义齿保存了重度牙体缺损患者的残根残冠,有效提高咀嚼效率。结论:新型内插销式桩核冠固定义在深覆患者重度牙体缺损修复方面具有独特优势。     

尿道移行上皮细胞与生物可降解尿道支架体外复合培养的研究

目的：研究体外培养的兔尿道上皮细胞在生物可降解性网状尿道支架上的贴附和生长增殖情况,观察其对尿道上皮细胞形态和功能的影响,利用组织工程技术培养种植细胞的尿道内支架。方法：应用机械分离与酶消化法分离培养兔尿道移行上皮细胞,并在体外行原代培养与扩增后制成细胞悬液接种在网状尿道支架上,形成尿道移行上皮细胞-支架复合物。采用免疫组织化学、荧光染色法鉴定尿道上皮细胞及其活性;采用倒置显微镜、扫描电镜观察尿道上皮细胞在支架表面吸附与生长状态。结果：网状尿道支架具有良好的生物相容性,能使尿道移行上皮细胞增殖,不影响其活性。尿道移行上皮细胞在尿道支架上贴附生长良好,1～2天后完全贴壁,3～7天细胞生长增殖活跃,支架网眼内充满上皮细胞,长期培养仍保持尿道移行上皮细胞特性,扫描电镜可见上皮细胞与网状支架贴附紧密,适度伸展并有基质分泌。结论：网状尿道支架适合尿道移行上皮细胞黏附生长．可作为尿道组织工程的细胞载体,利用组织工程方法可获得适于移植尿道细胞的组织工程化尿道。     

Synthesis,Characterization and Biomedical Properties of UV-Cured Polyurethane Acrylates Containing a Phosphorylcholine Structure

Abstract

In order to develop a simple, economical and rapid approach to incorporate 2-methacryloyloxyethyl phosphorylcholine (MPC) with other monomers without any solvent, we prepared a series of ultraviolet cured poly(urethane acrylate) (PUA) membranes containing different MPC content. Their chemical structure and surface properties were investigated by FT-IR, XPS, water swelling ratio and water contact angle measurement, while the biocompatibilities were evaluated through fibrinogen adsorptions, platelet adhesion and plasma recalcification time determination. The results demonstrate that the phosphorylcholine (PC) groups were successfully introduced into the PUA system by the UV-curing approach and the all PC-containing membranes showed better biocompatibility than those without PC moiety. The UV-curing method is potentially to be applied in the coating of medical devices which require biocompatibility and manufacturing efficiency.     

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??Objective    To evaluate the cytotoxicity?? biocompatibility and biological safety of PGMA pre-impregnated quartz fiber in vitro?? providing scientific basis for clinical application. Methods    According to standard of GBT16886.5-2003 and YYT0268-2008 documents?? the cellular cultivation and cytotoxicity test in vitro were conducted to evaluate the target materials on the morphology?? growth and proliferation of cultured cells ??L929 and GE1??. Results        The range of cell relative growth rate ??RGR?? of 50% and 100% extraction of non-polymerized composite were 44.59%-65.66% ??L929?? and 52.06%-62.86% ??GE1???? and the cytotoxicity was grade 2-3. The range of cell relative growth rate ??RGR?? of 50% and 100% extraction of polymerized composite were 90.56%-100.89% ??L929?? and 89.99%-101.21% ??GE1???? and the cytotoxicity was grade 0-1. Conclusion    Polymerized PGMA pre-impregnated quartz fiber is safe and fit for the clinical application.     

Synthesis and characterization of the biodegradable and elastic terpolymer poly(glycolide-co-L-lactide-co-ϵ-caprolactone) for mechano-active tissue engineering

We synthesized a series of tri-component biodegradable copolymers with elastic characteristics by ring-opening copolymerization of cyclic lactones, that is, glycolide, L-lactide, and ?-caprolactone, in the presence of stannous octoate as a catalyst. We evaluated the physical and chemical characteristics of poly(glycolide-co-L-lactide-co-?-caprolactone) (PGLCL) copolymers. The synthesized PGLCL had a high molecular weight of about 100?kD and an amorphous structure. It was confirmed that the physical and chemical properties of these terpolymers could be modulated by adjusting copolymer composition. PGLCL films exhibited rubber-like elasticity and showed almost complete recovery when subjected to 50% of the tensile strain. To examine the biodegradability of the PGLCL copolymers, we performed in vitro degradation tests for 12?weeks and observed changes in molecular weight, gross weight, and composition. These results showed that the glycolide was degraded most quickly and that ?-caprolactone was the slowest to degrade. Additionally, cytotoxicity tests revealed that none of the polymers were toxic. In summary, the mechanical properties and biodegradability of PGLCL terpolymers could be controlled by changing the monomer content, which may be useful for a wide range of tissue engineering applications based on mechanical property requirements.     

Cell culture tests for assessing the tolerance of soft tissue to variously modified titanium surfaces

The aim of our research project was to achieve an improvement in the integration of enossal dental implants in the region of peri-implantary soft tissue. Improvement in the adhesion of the gingiva of the surface of enossal implants was to be achieved by modification of the titanium surface. The effect of different modifications on the biocompatibility of the modified titanium surfaces was tested: sulfur dioxide plasma treatment of titanium; acetylene plasma treatment of titanium followed by sulfur dioxide plasma etching; plasma nitration of titanium; replacement of titanium by glycidoxypropyltrimethoxy silane; coating titanium with poly[(ethene-co-vinyl acetate)-graft-vinyl chloride] and coating titanium with fibronectin. Determination of the chemical composition of the surface was carried out using X-ray photospectroscopy. The adsorption of fibronectin at the surface of the titanium was tested using an Enzyme Linked Immunosorbent Assay. In selected in vitro tests with human gingival fibroblasts, cell morphology was assessed using scanning electron microscopy and light microscopy. Cell proliferation and protein synthesis, as well as the activity of mitochondrial dehydrogenases were evaluated. By means of centrifugation and by determining initial cell adhesion, the adhesion of gingival fibroblasts was investigated. According to the kind of modification made to the titanium surfaces, it was possible to observe differences in the cellular behavior of gingiva fibroblasts on the differently modified surfaces of the implants. Coating the titanium using fibronectin produced optimization of cell growth and improvement in the adhesion of gingiva fibroblasts to the implant surface. In contrast, modification of the titanium with poly[(ethene-co-vinyl acetate)-graft-vinyl chloride] generally resulted in a deterioration of the biocompatibility of the surface. A marked correlation between the cellular compatibility of the modified titanium and the surface modification made did not become apparent. One reason for this is the large number of parameters determining the interaction between implant and tissue.