巯基壳聚糖性能的体外评价

目的研究和评价巯基壳聚糖各项性能。方法用重量法考察本产物的溶胀性能,并通过溶菌酶实验考察降解性能。结果本巯基壳聚糖的溶胀行为和未经修饰的聚合物在同一范围内,而且巯基壳聚糖可被溶菌酶生物降解。结论巯基壳聚糖是新型给药系统中很有前景的功能性敷料。     

鼻用氟脲嘧啶壳聚糖微球的体外释放及溶胀影响因素

目的考察壳聚糖脱乙酰度、壳聚糖浓度、固化剂用量、固化时间以及介质pH值对氟脲嘧啶壳聚糖微球的体外释放与溶胀的影响。方法乳化化学交联法制备氟脲嘧啶鼻用微球,动态透析法检测微球的体外释放特性;根据微球吸水前后质量变化测定微球的溶胀率。结果壳聚糖的脱乙酰度越高、固化剂用量越大、固化时间越长则微球的溶胀越慢,微球的体外释放越慢;壳聚糖浓度的增加则使微球的溶胀度增加,体外释放量减少;释放介质的pH值对微球的溶胀性能影响很大,在酸性条件下微球溶胀度高且释药加快。结论影响壳聚糖微球溶胀的因素顺序为介质的pH值>固化剂用量>固化时间>壳聚糖浓度≈壳聚糖脱乙酰度;影响壳聚糖微球体外释放的因素顺序为固化剂用量>壳聚糖脱乙酰度>壳聚糖浓度,而固化时间和介质的pH值对体外释放无显著性影响。     

高偶合巯基壳聚糖的合成和体外评价

目的:用新合成法合成较高巯基含量的壳聚糖巯基醋酸偶合物,并进一步评价其各项性能.方法:用碳化二亚胺和N-羟基磺酸基丁二酰亚胺的活化,提高巯基醋酸与壳聚糖共价偶合率.用重量法考察本产物的溶胀性能,用离体的猪肠黏膜上皮测定膜黏附性,通过溶菌酶实验考察降解性能,并采用单层Caco-2细胞为模版测定14C-甘露糖醇在壳聚糖巯基醋酸偶合物作用下的渗透性能等.结果:本合成法所得巯基壳聚糖的巯基含量可达7.56%,总黏附功是未经修饰聚合物的16.3倍,偶合物的溶胀行为和未经修饰的聚合物在同一范围内,而且高偶合巯基壳聚糖也可被溶菌酶生物降解.结论:巯基含量的增加可提高壳聚糖巯基醋酸偶合物的多项生物学性能.高偶合巯基壳聚糖是新型给药系统中很有前景的功能性敷料.     

复合rhBMP-2壳聚糖水凝胶的制备及其缓释性能研究

【】目的 通过构建新型负载重组人骨形态发生蛋白2(Recombinant Human Bone Morphogenetic Protein 2 rhBMP-2)壳聚糖水凝胶缓释系统来获得持续稳定释放的rhBMP-2细胞因子。方法 分别用1.0mg/ml、1.5mg/ml、2.0mg/ml壳聚糖(Chitosan CS)和0.5mg/ml、0.7mg/ml、1.0mg/ml三聚磷酸钠(Sodium Tripolyphosphate TPP)按总质量比5:1交联,比较各组溶胀系数,扫描电镜(SEM)观察各组凝胶微观表面形态,采用最佳溶胀度组水凝胶复合rhBMP-2,酶联免疫吸附试剂盒(ELISA)动态检测负载rhBMP-2壳聚糖水凝胶的缓释特性。结果 1.5mg/ml CS与0.5mg/ml TPP交联所得水凝胶表现出最低溶胀度,为238.28?Ee28.06%,该组溶胀度与其他各组比较,差异具有统计学意义(P﹤0.05)。其冻干水凝胶扫描电镜下呈三维网状结构,内部均匀分布壳聚糖微球,将其负载rhBMP-2后获得体外释放曲线如下。结论 新型rhBMP-2壳聚糖水凝胶制备流程简单,且具有很好的承载和缓释rhBMP-2的能力,为rhBMP-2在骨组织工程中的应用提供了良好的新途径。     

不同分子量和脱乙酰度壳聚糖用作组织工程材料的性质评价

目的对不同相对分子质量(Mr)和脱乙酰度的壳聚糖用于组织再生修复的前景进行评价。方法MTT法测定Mr为5万,20万,50万,100万,脱乙酰度分别为85%和95%的8种壳聚糖对骨髓间充质干细胞的亲和性,测定它们在体外、体内的降解特性,并通过检测接触角考察了它们的亲水性。结果在所研究的8种壳聚糖中,Mr为50万和100万,脱乙酰度为95%的壳聚糖更利于骨髓间充质干细胞的黏附生长,亲水性较强,在体内埋植8~16周后仍能保持形态完整,利于种子细胞生存。结论Mr为50万和100万,脱乙酰度为95%的壳聚糖能够与骨髓间充质干细胞复合用于组织再生修复。     

改性京尼平交联壳聚糖人工神经导管的柔韧性和机械强度

目的探讨原花青素改性的京尼平交联壳聚糖人工神经导管的柔韧性和机械强度。方法采用不同含量的原花青素和京尼平、壳聚糖进行交联,从而对壳聚糖材料进行不同程度的改性。测试和分析去其溶失率、交联度、力学性能及细胞毒性,确定最佳交联条件。结果原花青素含量在8%-12%w/v区间时,原花青素和京尼平(0.10%w/v)共同交联形成的壳聚糖导管具有较高的交联度和较低的溶失率,同时柔韧性比纯京尼平壳聚糖导管更好。其与雪旺细胞共培养3d,细胞生长状态良好。结论作为生物交联物,原花青素改性的京尼平交联壳聚糖导管用于外周神经的修复具有良好的应用前景。     

神经营养因子与面神经再生的研究进展

面神经损伤是常见的口腔颌面部损伤。面神经的再生机制对于损伤后神经的修复具有重要意义,随着对面神经修复过程的深入研究,人们发现神经营养因子对于面神经的再生和功能恢复有着重要的作用。本文对神经营养因子与面神经再生的研究进展进行了综述。     

葡聚糖栓塞微球溶胀特性的研究

目的:对葡聚糖栓塞微球的溶胀特性进行研究。方法:采用凝胶色谱法。将样品用生理盐水分散装填于不锈钢柱管中,注入牛血清白蛋白(BSA)和苯丙氨酸2种不同分子量物质的混合溶液,在280nm波长下记录BSA与苯丙氨酸的色谱保留行为,根据二者保留时间之差来计算凝胶柱中待检测微球的内水体积,并以此为指标对样品分别以磷酸盐缓冲溶液和生理盐水为溶胀溶液进行微球体内、外溶胀特性的比较,并对经高温灭菌处理、室温放置24个月、在模拟的人体生理环境中的溶胀稳定性进行研究。结果:葡聚糖栓塞微球在模拟的体内、外的溶胀特性一致,其在上述3种条件下溶胀性均能保持一定的稳定性。结论:葡聚糖栓塞微球的溶胀稳定性较好;采用凝胶色谱法可表征葡聚糖栓塞微球溶胀体积并用于其质量研究。     

腮腺浅叶良性肿瘤部分切除术与传统切除术的临床效果观察

腮腺区的良性肿瘤以多形性腺瘤及腺淋巴瘤最为常见,传统的腮腺切除手术通常需要解剖面神经各分支,并于面神经浅面将腮腺浅叶、肿物和腮腺嚼肌筋膜一并切除.     

壳聚糖对实验室废水中Zn~（2＋）最佳吸附条件的研究

目的探讨壳聚糖吸附处理重金属离子Zn2＋的最佳工艺条件,以及再生后对其吸附性能的影响,以便为实际应用提供参考。方法建立实验室模拟废水,并采用壳聚糖对模拟废水中的微量重金属离子Zn2＋进行吸附试验,观察不同pH值、壳聚糖用量、时间、温度下最佳吸附效果。结果在实验室条件下,壳聚糖对Zn2＋最佳吸附条件是Zn2＋溶液pH为6,壳聚糖用量为0.4g,时间30min,温度为35℃。结论壳聚糖对水中微量重金属离子有较好的吸附效果,可作为重金属离子的吸附剂用于实验室重金属离子废水的处理。     

Nerve conduits based on immobilization of nerve growth factor onto modified chitosan by using genipin as a crosslinking agent

Incorporation of nerve growth factor (NGF) into a nerve conduit can improve peripheral nerve regeneration. Here, genipin, a natural and low toxic agent, was used to crosslink chitosan, a natural polysaccharide, and concurrently to immobilize NGF onto modified chitosan, followed by fabrication of chitosan (CS)-genipin (GP)-NGF nerve conduits. MTT test showed that the cell viability of Schwann cells cultured in the conduit extract was not significantly different from that in plain medium. The neurite outgrowth measurement and immunocytochemistry with anti-growth-associated protein-43 and anti-neurofilament indicated that NGF released from CS-GP-NGF nerve conduits retained the bioactivity of stimulating neuronal differentiation of PC12 cells. Fracture strength measurements and vitamin B12 release analysis confirmed that CS-GP-NGF nerve conduits possessed good mechanical properties and adequate permeability. We also investigated the in vitro release kinetics of NGF from CS-GP-NGF nerve conduits by ELISA. The continuous release profile of NGF, within a 60-day time span, consisted of an initial burst that was controlled by a concentration gradient-driven diffusion, followed by a zero-order release that was controlled by a degradation of chitosan matrix. Collectively, CS-GP-NGF nerve conduits had an integrated system for continuous release of NGF, thus holding promise for peripheral nerve repair applications.     

面神经解剖在80例腮腺手术患者中的应用

目的将面神经解剖技术应用于腮腺手术治疗中,并观察其临床应用效果。方法对比分析法是对应用顺行法与逆行法在实施腮腺手术的患者临床资料进行分析的一种方法,本文采用这种方法对我院自2011年3月至2013年3月收治的80例病患资料进行临床分析,按照随即抽取法将其分为A组与B组,其中A组患者应用顺行法（即通过找出面神经总干再分离各分支的方法）进行治疗,B组患者应用逆行法（即通过找出下颌缘支再经由其他分支找到主干的方法）进行治疗,每组患者各40例。结果A组与B组两种面神经解剖方法在腮腺手术中均取得了良好的临床解剖效果,对面部神经起到了很好的保护作用,其中A组神经功能损伤发生率为7．5％,B组神经功能损伤发生率为5％,两组术式治疗数据不存在明显差异,无具有统计学意义（P〉0．05）。除了切断恶性肿瘤侵犯面神经以外,没有一例病患出现面神经离断而导致的永久性面神经损伤,出现轻度的下领缘支受损的症状的患者有3例,出现颧支及颞支受损的症状的患者各有l例,随访3～6个月后,患者病症基本恢复。结论采用两种方法进行面神经解剖,具有良好的临床治疗效果,但是A组手术恢复时长明显短于B组,如果将两种方法相结合,则会起到保护面神经的作用,从而降低面神经的损伤率。     

明胶管修复周围神经缺损的实验研究

目的　了解明胶管 (gelatinconduit)在修复外周神经缺损中的作用。方法　用明胶制成长1.0cm、内径 1.0mm的导管 ,套接修复大鼠右侧坐骨神经缺损 6.0mm ,左侧从同样规格的硅胶管套接作对照 ,于术后 3月进行电生理学、免疫组织化学、辣根过氧化物酶 (HRP)示踪等检查。结果　明胶管内有较多的再生神经纤维。明胶管套接侧胫前肌肌湿重、有髓神经纤维直径方面优于硅酮管 (P <0 .0 5 ) ,明胶管变薄无异物反应及炎症反应、无粘连。辣根过氧化物酶示踪证实在相应的背根神经节找到阳性的神经元。结论　作为一种新材料 ,明胶管能有效桥接坐骨神经缺损     

Nanofiber scaffolds facilitate functional regeneration of peripheral nerve injury

Peripheral nerve injury still remains a refractory challenge for both clinical and basic researchers. A novel nanofiber conduit made of blood vessel and filled with amphiphilic hydrogel of self-assembling nanofiber scaffold (SAPNS) was implanted to repair a 10 mm nerve gap after sciatic nerve transection. Empty blood vessel conduit was implanted serving as control. Results showed that this novel nanofiber conduit enabled the peripheral axons to regenerate across and beyond the 10 mm gap. Motoneuron protection, axonal regeneration and remyelination were significantly enhanced with SAPNS scaffold treatments. The target reinnervation and functional recovery induced by the regenerative nerve conduit suggest that SAPNS-based conduit is highly promising application in the treatment of peripheral nerve defect.From the Clinical EditorIn this paper by Zhan et al, a novel self-assembling nanofiber scaffold is reported to promote regeneration of peripheral nerves in a sciatic nerve injury model. The promising results and the obvious medical need raises hope for a clinical translation of this approach hopefully in the near future.     

SMAS分离除皱术防止面神经额支损伤的应用解剖研究

目的 为面颞区SMAS分离除皱术防止面神经额支损伤提供解剖学依据。方法 在4例新鲜标本和26例防腐固定标本上，解剖观测了面神经额支的走行、分布、毗邻，建立相关的坐标体系，并得出面神经额支的体表定位的坐标参数，分析额支的分布特点及预防其损伤的手术操作方法。结果 额支由颞支发出后，在颞浅筋膜深面由后下方向前上方走行，一些进入额肌，一些进入眼轮匝肌。面神经额支在向前上方走行的过程中，不断分支、吻合，分布区域呈扇形展开。其右侧最前支的坐标值（mm）为：（0．0，-4．5±3．4）、（4．0，1．6±4．6）、（8．0，4．3±4．5）、（12．0，8．1±5．1）、（16．0，10．4±5．4）、（20．0，12．3±5．7）、（24．0，14，4±4．6）、（28，0，17．3±5．4）；右侧最后支的坐标值为：（-20．0，1．1±5．4）、（-16．0，11．2±4．2）、（-12．0，17．3±5．5）、（-8．0，22．7±5．7）、（-4．0，26．4±5．5）、（0．0，28．1±5．1）；其左侧最前支的坐标值为：（4．0，-3．1±3．4）、（0．0，-2．5±3．7）、（-4．0，1．9±3．4）、（-8．0，4．7±5．2）、（-12．0，7．9．1±4．6）、（-16．0，11．3±5．1）、（-20．0，13．3±4．8）、（-24．0，15．4±4．4）、（-28．0，17．8±5．4）；左侧最后支的坐标值为：（24．0，-1．0±3．4）、（20．0，1．8±4．3）、（16．0，10．6±5．1）、（12．0，16．7±5．7）、（8．0，23．3±4．9）、（4．0，25．8±5．7）、（0．0，27．9±5．8）。结论 临床医生熟悉面神经额支的位置、走行，有利于减少SMAS分离除皱术对其损伤。     

沿下颌缘支逆向分离面神经腮腺手术57例临床分析

目的：分析沿下颌缘支逆向分离面神经方法切除腮腺肿瘤的手术效果。方法：统计2003年1月～2008年1月腮腺肿瘤手术57例患者的病例资料,所有患者手术时采用沿下颌缘支逆向分离面神经的方法。结果：全组患者顺利完成手术,术后2例并发涎瘘,3例面神经损伤。结论：沿下颌缘支逆向分离面神经的腮腺手术方法从浅到深分离,操作方便、术野清晰、创伤极小、出血较少、优点明显、效果满意。     

Controlled nerve growth factor release from multi-ply alginate/chitosan-based nerve conduits

The delivery kinetics of growth factors has been suggested to play an important role in the regeneration of peripheral nerves following axotomy. In this context, we designed a nerve conduit (NC) with adjustable release kinetics of nerve growth factor (NGF). A multi-ply system was designed where NC consisting of a polyelectrolyte alginate/chitosan complex was coated with layers of poly(lactide-co-glycolide) (PLGA) to control the release of embedded NGF. Prior to assessing the in vitro NGF release from NC, various release test media, with and without stabilizers for NGF, were evaluated to ensure adequate quantification of NGF by ELISA. Citrate (pH 5.0) and acetate (pH 5.5) buffered saline solutions containing 0.05% Tween 20 yielded the most reliable results for ELISA active NGF. The in vitro release experiments revealed that the best results in terms of reproducibility and release control were achieved when the NGF was embedded between two PLGA layers and the ends of the NC tightly sealed by the PLGA coatings. The release kinetics could be efficiently adjusted by accommodating NGF at different radial locations within the NC. A sustained release of bioactive NGF in the low nanogram per day range was obtained for at least 15days. In conclusion, the developed multi-ply NGF loaded NC is considered a suitable candidate for future implantation studies to gain insight into the relationship between local growth factor availability and nerve regeneration.     

人参皂苷Rg_1对去卵巢大鼠面神经损伤修复的作用研究

目的:研究人参皂苷Rg1对去卵巢大鼠面神经损伤的修复作用。方法:取成年切除卵巢SD大鼠48只,随机分为假手术(等量生理盐水)、模型(等量生理盐水)、神经生长因子(NGF,10mg·kg-1)、人参皂苷Rg(110mg·kg-1)组。从复制模型开始各组灌胃相应药物,观察大鼠行为变化;光镜、透射电镜观察大鼠面神经核细胞形态学变化;免疫组化检测BDNF蛋白的表达。结果:人参皂苷Rg1组大鼠面神经元核细胞形态略有改善。模型、NGF、人参皂苷Rg1组大鼠面神经损伤3d后面神经核BDNF蛋白表达升高,7d后有所下降,14d后又升高。光镜、透射电镜观察到人参皂苷Rg1组再生神经纤维厚度优于模型组(P<0.05)。结论:人参皂苷Rg1能促进去卵巢大鼠面神经损伤的面神经元修复,可能与其促进BDNF蛋白表达有关。     

Hydrogels based on interpenetrating network of chitosan and polyvinyl pyrrolidone for pH-sensitive delivery of repaglinide

The aim of this study was to develop a pH-sensitive chitosan/polyvinyl pyrrolidone (PVP) based controlled drug release system for repaglinide. The hydrogels were synthesised by crosslinking chitosan and PVP blend with glutaraldehyde to form a semi-interpenetrating polymer network (semi-IPN). These semi-IPNs were studied for their content uniformity, swelling index (SI), mucoadhesion, wettability, in vitro release and their release kinetics. The hydrogels showed more than 95% loading of repaglinide. These hydrogels showed high swelling and mucoadhesion under acidic conditions. The swelling was found due to the protonation of a primary amino group on chitosan. In acidic condition chitosan was ionized, and adhesion occurred between the positively charged chitosan and the negatively charged mucus. In the physiological condition less swelling was noticed. In vitro release study revealed that formulation containing chitosan (2% w/v) and PVP (4% w/v) in the ratio of 14:6 w/w showed complete drug release after 12h. Release profile showed that all the formulations followed non-fickian diffusion mechanism (diffusion coupled with swelling). Fourier transform infrared (FTIR) spectroscopic analysis revealed proper crosslinking of polymer and formation of semi-IPN as well as presence of drug in the formulation. Differential scanning calorimetry (DSC) and powder x-ray diffraction (p-XRD) study revealed the presence of repaglinide in crystalline form in the formulations. The surface morphology of semi-IPN was studied before and after dissolution in simulated gastric fluid (SGF, pH 1.2) which indicated generation of open channel-like structure in hydrogel after dissolution. The results of study suggest that semi-IPNs of chitosan/PVP are potent candidates for delivery of repaglinide in acidic environment.     

Polymeric microspheres for drug delivery to the oral cavity: an in vitro evaluation of mucoadhesive potential

Polymeric microparticles were fabricated from Carbopol, polycarbophil, chitosan, or Gantrez using a "water-in-oil emulsification" solvent evaporation method. Mean particle sizes, as determined by laser diffraction, were in the range 23-38 microm. Electron microscopy revealed that all microparticles were spherical and of smooth surface morphology. In pH 7.0 phosphate buffered saline, the microspheres exhibited significantly increased swelling ratios and longer half-times of swelling than the corresponding powdered polymers. The relative merits of the potential usefulness of these microspheres as formulation tools for the enhanced retention of a therapeutic entity within the oral mucosa were evaluated by in vitro mucoadhesion tests. Tensile tests showed that all microspheres under consideration were capable of adhering to porcine esophageal mucosa, with particles prepared from the poly(acrylic acid)s exhibiting greater mucoadhesive strength than those constructed from chitosan or Gantrez. However, in elution experiments involving a challenge with artificial saliva, particles of chitosan or Gantrez were retained onto mucosal tissue for longer time periods than those assembled from the poly(acrylic acid)s.