组织工程化口腔黏膜载体材料聚乳酸羟基乙酸膜的制作及物理特性

目的 制作组织工程化口腔黏膜载体材料,研究其物理特性。方法 不同比例的聚乳酸(PLA)和聚乙醇酸(PLG)按常规成膜技术制备聚乳酸羟基乙酸(PLGA)。测定其孔隙率,倒置相差显微镜和电子扫描显微镜(SEM)观察其物理特性。结果 PIGAⅠ、Ⅱ、Ⅲ为平滑透明膜,孔隙率10.56％、18.24％、8.64％,SEM观察呈现数目不等微孔和纤维交织样结构;PIGAⅠV及改性膜不透明,较脆,孔隙率为56.39％左右,SEM观察为泡孔网海绵状。结论 PLGA Ⅰ、Ⅱ、Ⅲ具较好的透明度及孔隙率,可被用作组织工程化口腔黏膜载体材料。     

原花青素在多孔薄膜中实现高效加载和长效释放的研究

目的 探讨了原花青素药物分子通过材料表面介导的方式实现长效扩散型释放行为的可能性。方法 将原花青素分散在水中配制为药物溶液,与三氯甲烷共混后通过超声乳化的方式将混合液制备成为稳定的反相乳液。在高湿度环境条件下,将所制得的乳液浇筑在聚苯乙烯平面膜片上,待有机溶剂和水分挥发后获得表面和本体层均具有多孔结构的聚合物薄膜,并以此一步法实现原花青素在薄膜中的封装加载。最后将所制备得到的药物加载薄膜在磷酸缓冲盐溶液中浸泡进行药物释放实验,分时段取出缓冲液样品进行光谱表征确定原花青素的释放量,以此实现在28天内对原花青素释放行为的跟踪表征。结果 利用反相乳液浇筑致孔的方法,可以制备具有多层多孔结构的载药聚合物薄膜。经过乳液中水油比的调节,可以实现薄膜表层和本体层的多孔结构的调控。利用含水溶性荧光素乳液的浇筑成膜实验,并通过激光共聚焦显微镜结果证实了由反相乳液的乳液水滴所携带的亲水组分可以高效地实现在所形成多孔结构中的选择性分布,证明了原花青素组分在多孔膜当中可以实现有效加载。在这种多孔多层结构的薄膜当中所加载的原花青素可以实现超过28天以上的长效缓释,其释放行为遵循了Fickian扩散式机理。结论 利用聚合物多孔薄膜或者涂层作为药物载体,可以实现有效的药物加载和长效型释放,将能为设计高效灵活的药物释放体系提供有效的参考。     

Treatment of sphenoid dysplasia with a titanium-reinforced porous polyethylene implant in orbitofrontal neurofibroma: Report of three cases

Orbital manifestations occur in less than 1% of patients with neurofibromatosis type 1 (NF1). These manifestations are frequently associated with sphenoid wing dysplasia. The typical radiologic feature is partial or total loss of the greater wing of the sphenoid bone, which leads to herniation of the temporal lobe through the orbital cavity resulting in proptosis and pulsating exophthalmos. Traditional reconstruction of this bone defect involves split bone grafting or titanium mesh. However, these techniques have some limitations due to bone resorption and infection risk. We report the use of 0.85 mm titanium-reinforced porous polyethylene implant sheet in three cases of orbital neurofibromatosis with sphenoid dysplasia. The role of this material was to create a barrier between the brain and orbital cavity. The implant sheet was modeled intraoperatively to reconstruct the orbital cavity anatomy and fitted without any screws. The malleability of the implant allows quick reconstruction of the curved orbital skeleton. Furthermore, the implant doesn't interfere with postoperative imaging and may decrease risk infection.     

Comparing the ESA HPLC total homocysteine assay with electrochemical detection to the CDC in-house HPLC assay with fluorescence detection

Background: Environmental science has developed a simple high performance liquid chromatography (HPLC) assay with electrochemical detection for total homocysteine (tHcy) measurement that does not require derivatization of free thiols. We evaluated this method and compared it with the CDC HPLC assay with fluorescence detection (FD). Methods: tHcy is measured after reduction of disulfides/protein-bound thiols and protein precipitation using four channels of an ESA CoulArray detector. -homocystine is used as calibrator, penicillamine as internal standard. Results: Aqueous calibration of the ESA assay resulted in overestimation of tHcy by 30% compared to the HPLC-FD method. Calibration in plasma alleviated the matrix effect. The within- (n=3) and between-run (n=20) imprecision was <6%, the linearity up to 100 μmol/l was excellent, and the recovery of tHcy added to plasma was nearly complete (98.7%±2.3%). Good correlation was observed between both methods for 266 plasma samples. The ESA assay showed a minimal negative bias of 0.28 μmol/l (3.3%). Conclusion: The ESA tHcy assay performed well in terms of accuracy and precision, and showed good agreement with the CDC HPLC-FD assay when calibrated in plasma. The major advantage of this assay is that it does not require sample derivatization. Disadvantages include instability of the prepared samples for prolonged storage and matrix effects.     

Fabrication and Evaluation of Porous Keratin/chitosan (KCS) Scaffolds for Effectively Accelerating Wound Healing*

ObjectiveTo develop a dressing with desired antibacterial activity, good water maintaining ability and mechanical properties for wound healing and skin regeneration. MethodsThe chitosan with different concentrations were added in keratin solution to form porous keratin/chitosan (KCS) scaffolds. The morphological characteristics, chemical composition, wettability, porosity, swelling ratio and degradation of the scaffolds were evaluated. The antibacterial activity was tested by usingS. aureusandE. colisuspension for 2 h. And L929 fibroblast cells culture was used to evaluate the cytotoxicity of the KCS scaffolds. ResultsThe adding of chitosan could increase the hydrophobicity, decrease porosity, swelling ratio and degradation rate of the KCS porous scaffolds.Mechanical properties of KCS scaffolds could be enhanced and well adjusted by chitosan. KCS scaffolds could obviously decrease bacteria number.The proliferation of fibroblast cells in porous KCS patch increased firstly and then decreased with the increase of chitosan concentration. It was appropriate to add 400 μg/mL chitosan to form porous KCS scaffold for achieving best cell attachment and proliferation compared with other samples. ConclusionThe porous KCS scaffold may be used as implanted scaffold materials forpromoting wound healing and skinregeneration.     

多孔钽颗粒在下颌骨缺损修复中的作用

目的 评价多孔钽颗粒对下颌骨骨缺损的修复效果.方法 首先拔出比格犬双侧下颌前磨牙,待拔牙创愈合后(3个月)采用牙科种植机在下颌骨缺牙区构建颌骨骨缺损模型,随即将多孔钽颗粒(实验组,n=9)和Bio-oss骨粉(对照组,n=9)分别植入右侧和左侧下颌骨骨缺损区内.半流食喂养3个月后,双侧下颌骨行X线摄片比较2组材料修复骨缺损的能力,然后采用EXAKT切磨机制取硬组织切片,行甲苯胺蓝染色后于显微镜下观察新骨成熟情况.结果 3个月后,大体标本和X线摄片发现:实验组和对照组颌骨骨缺损区内均有新骨生成;按照X线评分标准对骨形成及塑形情况进行评价发现:实验组评分高于对照组[(9.54 ±0.10) vs (8.98 ±0.09),P＜0.05],差异有统计学意义.硬组织切片染色观察发现:实验组缺损区骨组织较对照组更为成熟,且包绕了大量的多孔钽颗粒,其相互交联呈网状;虽然对照组(Bio-oss骨粉颗粒)周围有较成熟的骨组织包绕,但颗粒之间仍有大量骨陷窝存在.结论 实验结果显示多孔钽颗粒具有良好的诱导成骨能力,其修复颌骨缺损效果优于临床常用的Bio-oss骨粉.     

Optimization of the defibrillation current density in the heart region by a two-layer segmented electrode

Transthoracic defibrillation is a procedure applying high intensity electrical current through the thorax region by electrodes, in order to simultaneously activate most of the myocardial cells, thus enforcing them to reinstate a normal rhythm. A solution is proposed for analysis and synthesis of the current density distribution field J in the heart region. In an attempt to reach uniform excitation of the greatest possible quantity of myocardial cells, a field image is searched for, with the J-vector uniformity distribution as a criterion. The finite element method and the method of approximating functions are used, as well as nonlinear programming. This approach resulted in designing a two-layer defibrillation electrode, with the layer applied to the thorax divided in three different resistivity regions.     

Tantalum Cones in Revision Total Knee Arthroplasty. A Promising Short-Term Result With 29 Cones in 21 Patients

Twenty-nine porous tantalum metaphyseal cones were implanted in 21 patients (14 women and 7 men) during revision TKA. The average age at the time of the procedure was 73.3 years. Sixteen revisions were considered aseptic and 5 were reimplantations after sepsis. Eight patients had stemmed revision implants and thirteen primary designs. According to the Anderson Orthopaedic Research Institute bone defect classification, femoral defects were rated as F3 in 14 knees and F2B in 3 knees. Tibial defects were rated as T2A in 3 cases, T2B in 3 cases and T3 in 5 cases. A femoral cone was inserted in 10 patients, a double cone (femur and tibia) in 8, and a single tibial cone in 3. A rotating hinge knee prosthesis (RHK, Zimmer) was inserted in 10 patients and a constrained condylar prosthesis (LCCK, Zimmer) in 11 patients. The diaphysis was cemented in 9 cases and, in 11 cases, just the metaphysis. At an average follow up of 36 months only one reconstruction was removed due to persistent infection. All metaphyseal cones showed evidence of stable osseointegration. According to the Knee Society Score the results were rated as excellent in 12 cases, good in 5 cases, fair in 3 and poor in 1 case. In the short term, porous tantalum metaphyseal cones provided structural support for large femoral and tibial defects. They also provided the environment for bone graft osseointegration, repair of femoral fractures and effective interdigitation of cement mantle into the trabecular metal cone.