首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 312 毫秒
1.
摘要 背景:骨组织工程支架材料由最初的自体骨,软骨材料到生物活性陶瓷,乃至后来的有机材料胶原蛋白等细胞外基质材料,其生物相容性及性能越来越优越,越来越接近体内的真实情况。但是这些材料在抗压性及强度方面还有待进一步提高。 目的:应用胶原与壳聚糖制备生物支架并对其检测其生物学性质,为骨、软骨缺损提供移植替代物。 方法:将不同比例壳聚糖-胶原蛋白溶解,经冷冻冻干后紫外线交联后冷冻干燥,二次冻干制备好支架。检测不同比例支架的孔隙率,降解率,溶胀率。扫描电镜观察孔径的大小及形态。 结果与结论:制备的支架外观呈海绵多孔状。支架的孔径大小随着胶原比例增加而减小。胶原比例的增加对支架孔隙率的影响较轻微。支架的溶胀率可达到80%左右,支架的溶胀程度随胶原比例增加而减少。胶原含量越大支架柔韧度增加明显。支架的降解率随着胶原比例增加而增加,而壳聚糖含量越高,降解速度越慢。结果提示,通过调整壳聚糖-胶原蛋白比例使支架具有作为骨、软骨缺损移植材料的替代物可能。 关键词:壳聚糖;胶原蛋白;骨;生物支架;组织工程 doi:10.3969/j.issn.1673-8225.2010.42.006  相似文献   

2.
背景:很多研究表明丝素蛋白、壳聚糖为天然高分子材料,无毒无味,有良好的生物特性和理化性质。 目的:探讨符合软骨组织工程支架材料要求的丝素蛋白/壳聚糖三维支架材料制备方法。 方法:将丝素蛋白与壳聚糖按质量比分别为3∶1,1∶1,1∶3,0∶1的比例混合制备丝素蛋白-壳聚糖复合材料,通过孔径大小、孔隙率、吸水膨胀率及热水溶失率的测定,寻找丝素蛋白/壳聚糖最佳混合比例。 结果与结论:丝素蛋白/壳聚糖按质量1∶1的比例混合更符合要求:孔径90~280 μm,平均孔径为151.72 μm;孔隙率为(92.72±4.78)%;吸水膨胀率为(141.10±6.87)%;热水溶失率交联后较交联前降低,交联前后比较差异有显著性意义(P < 0.05)。说明丝素蛋白/壳聚糖按1∶1复合支架材料符合软骨组织工程支架材料理化性质的要求,该材料有望作为软骨组织工程研究较理想的支架材料。  相似文献   

3.
背景:组织工程中,种子细胞需依赖于细胞外基质的存在才能发挥功能。因此支架材料的选择具有重大意义。 目的:制备一种新型改性壳聚糖-胶原-羟基磷灰石复合支架,优化易于细胞黏附的组织工程支架材料工艺。 方法:壳聚糖与透明质酸进行交联,红外和差示扫描量热图谱检测其结构;改性壳聚糖与胶原按1∶2,1∶1和2∶1制备3种改性壳聚糖-胶原-羟基磷灰石复合支架,将复合支架与成骨细胞MC3T3-E1联合培养,CCK-8法检测增殖,绘制生长曲线。 结果与结论:透明质酸和壳聚糖以酰胺键形成交联的新化合物,孔径在50~250 μm之间,孔隙率随着胶原水平、弹性模量的增加而增加,而密度则减少;增加胶原的含量在细胞联合培养初期有利于细胞对支架的黏附和增殖,但从第10天开始,3种样品中细胞数量相差不大,均出现平台期;苏木精-伊红染色发现成骨细胞在培养初期沿着支架材料内部空隙贴壁生长,随着培养天数的增加,贴壁细胞呈集落样生长,可明显看到细胞间连接。说明透明质酸改性壳聚糖/胶原/纳米羟基磷灰石复合材料可以作为骨支架材料供成骨细胞黏附、增殖,其中胶原与壳聚糖的体积比为1∶1为较优配比。  相似文献   

4.
背景:聚乳酸-羟基乙酸可作为尿道替代物进行组织缺损的修复。 目的:观察电纺丝法制备聚乳酸-羟基乙酸共聚物可降解尿道支架的可行性,并评价支架管的体外降解性能。 方法:采用电纺丝技术制备纳米聚乳酸-羟基乙酸共聚物(摩尔比80∶20)尿道支架管,并以戊二醛对支架进行交联、改性,将交联后支架截成长约1 cm小段并浸于尿液中进行体外降解实验。 结果与结论:支架管具有纳米结构,孔隙率约89%,孔径(32±19) µm;交联后可见纤维表面变粗糙,但纤维丝直径、孔径及孔隙率与交联前差异无显著性意义(P > 0.05),但交联后支架管力学性能显著提高。支架降解初期速度相对较快,中后期降解速度减慢,至8周时材料质量损失约50%,第10周完全崩解。材料在体内降解过程中相对分子质量的变化趋势与质量损失大体相同,降解早期相对分子质量下降相对较快,后期下降速度减慢并趋于平稳。表明采用电纺丝技术制备的纳米聚乳酸-羟基乙酸共聚物尿道支架可满足尿道组织工程支架的要求。  相似文献   

5.
背景:目前软骨支架材料的种类比较多,但还没有一种材料能完全符合软骨修复的要求。 目的:观察在混合材料胶原-壳聚糖支架中软骨细胞的生长情况。 方法:采用冷冻干燥法将质量分数为2%胶原与3%壳聚糖混合制备胶原-壳聚糖多孔支架。将分离培养的第2代兔软骨细胞接种到胶原-壳聚糖支架上,对照组将软骨细胞接种到无支架的培养板中。观察支架的孔隙率、吸水性及内部形态结构,MTT法检测软骨细胞在支架上的增殖情况,组织切片苏木精-伊红染色,扫描电镜观察细胞在支架的生长、贴附情况,RT-PCR检测细胞支架复合物蛋白聚糖和Ⅱ型胶原mRNA表达情况。 结果与结论:胶原-壳聚糖支架的吸水性为(80.0±0.55)%,孔隙率为(88.5±1.5)%,孔径为100~150 μm,复合细胞培养2周后,细胞增殖活力高,软骨细胞分泌的蛋白聚糖和Ⅱ型胶原mRNA表达明显高于对照组。说明质量分数为2%胶原与3%壳聚糖的混合支架适合软骨细胞生长和快速增殖,是一种良好的修复和重建软骨载体。  相似文献   

6.
背景:骨组织工程骨构建中如何使生长因子持续高效发挥作用是影响成骨速度和质量的关键,现多以各种材料的微球或支架作为缓释载体,但缓释作用有待提高。 目的:实验拟制备壳聚糖微球,然后复合到纳米羟基磷灰石/聚乳酸-羟基乙酸支架上,形成双重缓释作用,并测量对牛血清白蛋白的释放效果。 方法:以牛血清白蛋白为模型药物,采用乳化交联法制备壳聚糖微球。将微球与纳米羟基磷灰石、聚乳酸-羟基乙酸按一定比例混合,以冰粒子为致孔剂,采用冷冻干燥法制备壳聚糖微球/纳米羟基磷灰石/聚乳酸-羟基乙酸复合支架。利用扫描电镜、激光粒度分析仪、压泵仪和力学性能测试仪检测复合支架的形态性能,考察药物在缓释支架上的体外释放规律。 结果与结论:所制备的壳聚糖微球形态良好,呈规则圆球形,粒径集中分布在20~40 μm,微球药物包封率为86.5%,载药量为0.8%,随牛血清白蛋白初始用量的增加,载药量可升高至2.6%,但包封率下降至74.1%。壳聚糖微球能均匀分布在聚乳酸-羟基乙酸支架上,形成壳聚糖微球/纳米羟基磷灰石/聚乳酸-羟基乙酸复合支架,孔径为100~400 μm,孔隙率> 80%,压缩强度为1.1~2.3 MPa,10周降解率为26.5%。单纯纳米羟基磷灰石/聚乳酸-羟基乙酸支架其牛血清白蛋白在36 h累积释放量达85%以上,壳聚糖微球其牛血清白蛋白10 d累积释放量为33.6%,复合支架其牛血清白蛋白40 d累积释放量为81.5%。结果证实包埋壳聚糖微球的纳米羟基磷灰石/聚乳酸-羟基乙酸支架其压缩强度和降解速率合适,对蛋白类药物具有良好的缓释作用,有望作为组织工程的支架材料和生长因子的缓释载体。 关键词:聚乳酸-羟基乙酸;支架;壳聚糖;缓释载体;骨修复材料,组织工程;生物材料 doi:10.3969/j.issn.1673-8225.2010.03.017  相似文献   

7.
背景:在组织工程骺软骨构建过程中,采用何种载体承载已经扩增了的软骨细胞越来越受到人们的关注。 目的:探讨软骨细胞外基质与壳聚糖复合构建组织工程骺软骨支架的可行性并对其性能进行初步观察。 设计、时间及地点:体外观察实验,于2007-12/2009-03在解放军总医院骨科研究所完成。 材料:壳聚糖(脱乙酰度90%,Mr10×105)由青岛海汇生物工程公司提供。市售猪关节软骨。 方法:将新鲜的猪关节软骨在液体中粉碎,梯度离心后制备成3%软骨微丝悬液,将其按1︰1的比例与2%的壳聚糖溶液混合,采用冷冻冻干法制备脱细胞软骨基质三维多孔支架。 主要观察指标:对梯度乙醇处理再次干燥后支架材料进行组织学及扫描电镜观察,测定支架孔径和孔隙率、吸水率,并采用MTT 法分析支架浸提液毒性。分离培养兔骨髓间充质干细胞,用转化生长因子β1 成软骨诱导后种植至支架,倒置显微镜、电镜观察细胞在支架上的生长、分化情况。 结果:支架内孔洞相互连通,孔大小(161±31) μm,孔隙率为(90.1±1.6)%,吸水率为(2 361±132)%。组织学观察显示,三维多孔支架甲苯胺蓝染色、番红O染色、Ⅱ型胶原免疫组织化学染色均呈阳性。MTT 法结果显示支架无细胞毒性。细胞在支架表面黏附良好,分布均匀,并有基质分泌。 结论:制备的软骨细胞外基质和壳聚糖复合三维多孔支架结合良好,含有软骨细胞外基质主要成分,无毒,具备合适的孔径和孔隙率,生物相容性良好。  相似文献   

8.
摘要 背景:聚乳酸/壳聚糖纤维复合支架材料既可提高支架的力学性能,又可中和聚乳酸的酸性降解产物,提高生物相容性,从而满足组织工程支架的要求。 目的:制备用于组织工程的聚乳酸/壳聚糖纤维复合支架。 方法:采用热致相分离法制备了聚乳酸/壳聚糖纤维复合支架。测定了复合支架的微观形貌、孔隙率、压缩模量、降解特性、蛋白质吸附特性。 结果与结论:复合支架具有纳米微米共存的亚微观结构。在聚乳酸纳米纤维网络中引入壳聚糖纤维,有效地增强了复合支架的压缩模量和蛋白质吸附能力,复合支架压缩模量为纯聚乳酸纳米支架的3.75倍,蛋白质吸附能力比纯聚乳酸纳米支架提高了112%。体外降解实验表明复合支架降解液的pH值随时间的下降明显变缓。提示,在聚乳酸纳米纤维网络中引入壳聚糖纤维,可有效增强支架的压缩模量,提高蛋白质吸附能力,并可有效减缓聚乳酸降解过程中pH值的下降,克服酸性产物引发的无痛性炎症问题。 关键词:聚乳酸;壳聚糖;纳米复合;增强;支架 doi:10.3969/j.issn.1673-8225.2010.42.015  相似文献   

9.
背景:软骨组织工程的核心是利用少量的细胞经体外培养、扩增后,在一定环境下附着在三维多孔支架上,再将细胞/支架复合体移植到体内形成新的组织。 目的:拟构建兔骨髓间充质干细胞/壳聚糖-胶原支架复合体,探讨该支架作为软骨组织工程支架的可行性。 设计、时间及地点:细胞-支架学体外观察,于2008-03/2009-02在武警医学院生物化学教研室完成。 材料:日本大耳白兔6只用于分离培养骨髓间充质干细胞。医用壳聚糖粉末为山东奥康生物科技有限公司产品。Ⅰ型胶原为Sigma公司产品。 方法:取3%的壳聚糖和2%的胶原混合的醋酸溶液,倒入72孔板内,-20 ℃预冷冻10 h,冻干机冷冻抽干24 h制作成壳聚糖-胶原支架。取第3代兔骨髓间充质干细胞,以1×109 L-1密度接种于支架内,构建细胞/支架复合体。 主要观察指标:傅里叶红外光谱、扫描电镜、液体置换法测定支架的理化性质,观察三维培养后细胞在支架上的生长情况。 结果:壳聚糖-胶原支架孔径为160~380 μm,平均为270 μm,孔相通性好,支架孔隙率为(86.00±5.12)%。傅里叶红外光谱仪测定数据表明复合支架组成物有典型的壳聚糖、胶原峰,未发现有聚乙二醇峰。细胞/支架共培养24,48,72 h后,骨髓间充质干细胞可渗入支架多孔结构内,并黏附在支架上成簇生长,部分细胞已与支架融合。 结论:壳聚糖-胶原支架基本符合软骨组织工程支架要求,能够作为种子细胞的承载体。 关键词:壳聚糖-胶原支架;骨髓间充质干细胞;冻干法;软骨组织工程  相似文献   

10.
背景:关节软骨缺损的修复涉及到软骨和软骨下骨的双重修复,需要将骨与软骨组织工程结合起来,构建骨软骨双层支架,或者在同一支架上构建组织工程化骨软骨。 目的:观察胶原/壳聚糖/β-磷酸三钙层状梯度修复体对软骨细胞的吸附作用及对细胞生物学性状的影响,评价其作为关节软骨工程支架的可行性。 时间及地点:体外细胞学实验,于2007-12/2008-06在广东省构建与检测实验室进行。 材料:以胶原、壳聚糖、β-磷酸三钙制备复合支架,上层以胶原/壳聚糖为主,下层以胶原/壳聚糖/β-磷酸三钙为主,孔隙率≥ 90%,孔径100 μm。 方法:体外培养新西兰大白兔软骨细胞并成骨诱导3 周,使之吸附于多孔胶原/壳聚糖/β-磷酸三钙层状梯度修复体上三维立体培养3周。 主要观察指标:通过生长曲线、倒置相差显微镜、组织学、扫描电镜及免疫组织化学检测支架在三维立体培养对软骨细胞的表型、增殖及功能的影响。 结果:修复体/细胞体外培养3周,修复体上细胞数量明显增多,并分泌细胞基质,包裹在软骨细胞周围,Ⅱ型胶原免疫组织化学染色阳性。 结论:胶原/壳聚糖/β-磷酸三钙层状梯度修复体的细胞相容性良好,有望成为一种比较理想的关节软骨组织工程支架材料。  相似文献   

11.
In culturally diverse and immigrant receiving societies, immigrant youth can be subject to prejudice and discrimination. Such experiences can impact on immigrant youth’s cultural identity and influence their psychosocial outcomes. This paper presents findings of a study that examined cultural identity and experiences of prejudice and discrimination among Afghan (N = 9) and Iranian (N = 17) immigrant youth in Canada. The study had a prospective, comparative, longitudinal qualitative design. Data was gathered through focus groups, interviews, journals and field logs. Four main themes emerged on participants’ experiences of prejudice and discrimination: (a) societal factors influencing prejudice; (b) personal experiences of discrimination; (c) fear of disclosure and silenced cultural identity; and (d) resiliency and strength of cultural identity. Drawing from Rosenberg’s (Conceiving the self, Basic Books, New York, 1979) self-concept framework and Romero and Roberts (J. Adolesc., 21:641–656, 1998) distinction between prejudice and discrimination, results indicated that youth’s extant and presenting cultural identity were affected. Inclusive policies and practices are needed to promote youth integration in multicultural and immigrant receiving settings.
Nazilla KhanlouEmail:
  相似文献   

12.
Decades of intervention research have produced a rich body of evidence on the effects of psychotherapies and pharmacotherapies with children and adolescents. Here we summarize and critique that evidence. We review findings bearing on the efficacy of psychosocial treatments and medications under controlled experimental conditions. We also report evidence, where available, on the effectiveness of both classes of treatment with clinically referred youth treated in real-world clinical contexts. In general, the large body of evidence on efficacy contrasts sharply with the small base of evidence on effectiveness. Addressing this gap through an enriched research agenda could contribute importantly to linking scientific inquiry and clinical practice—to the benefit of both ventures. This is one element of a multifaceted agenda for future research and for synthesis of research, which will require the interplay of multiple disciplines related to child and adolescent mental health.  相似文献   

13.
本文目的是探讨癫痫共病抑郁的可能机制及临床诊疗。癫痫是一种常见的、慢性的、致残性的神经疾病,癫痫患者生活质量下降,存在明显的负性情绪,常伴发各种精神疾病。癫痫与抑郁具有共同的神经生物学基础,可能存在共同的发病机制。本文从癫痫共病抑郁的发病机制、临床诊断及治疗方面予以总结归纳。  相似文献   

14.
本文目的是对沙盘游戏疗法在地中海贫血患儿心理干预中的应用进行综述,以期为地中海贫血患儿的心理康复提供参考。地中海贫血是以珠蛋白生成障碍为主要特征的遗传性疾病,由于长期输血治疗,患儿存在较多的心理和行为问题。沙盘游戏疗法作为一种有效、实用的儿童心理治疗方法,对提高地中海贫血患儿的康复效果、改善生存质量有重要的临床意义。  相似文献   

15.
小胶质细胞和少突胶质细胞前体的培养和鉴定   总被引:1,自引:1,他引:0  
目的 探讨新生大鼠脑组织小胶质细胞(MG)和少突胶质细胞(OL)前体的分离和体外培养方法 . 方法 取新生2 d SD大鼠脑组织,体外原代培养混合胶质细胞7 d后,分别采用"改良振荡伴差速贴壁"法和"营养缺失伴振荡"法纯化培养MG和OL前体,并分别应用免疫荧光染色异凝集素-B4(IB4)和OL前体标记物(O4)进行鉴定.结果 混合胶质细胞培养7 d后呈明显三层增长,其中MG位于上层,星型胶质细胞位于底层,两者之间为2型少突星型(O2A)祖细胞.纯化培养后OL前体胞体呈小圆形,有双极或三极突起,MG则以阿米巴形、圆形居多,或边缘呈毛刺状.免疫荧光染色IB4显示绿色荧光,MG纯度达到90%以上.免疫荧光染色O4显示棕黄色荧光,OL前体纯度达到95%以上. 结论 采用"改良振荡伴差速贴壁"法以及"营养缺失伴振荡"法分别成功获取大量纯度高、活力好的MG和OL前体.  相似文献   

16.
本文目的是探讨发作性睡病与异态睡眠的诊断与治疗。发作性睡病被漏诊和误诊的几率较高,危害较大,共患异态睡眠比例高。文章从发作性睡病临床特征、REM睡眠的作用、发作性睡病与异态睡眠(睡眠瘫痪、睡眠幻觉、快眼动睡眠期行为障碍)共病特征及治疗这四个方面进行了讨论。  相似文献   

17.
Injuries from lightning and electrical injuries involve multiple systems of the body, however neurological symptoms are very widely reported. A disabling neuropsychological syndrome is also noted.This paper presents a comprehensive review of neurological and neuropsychological symptoms. Partial theories of causation for these injuries have been advanced, however, there is no convincing explanation for both delay in onset of symptoms and also the genesis of the neuropsychological syndrome. A theory of causation is proposed which satisfies both these constraints.This theory suggests circulating hormones such as cortisol, together with nitric oxide and oxidant free radicals from glutamatergic hyper-stimulation, act on tissues remote from the injury path including the hippocampus.This theory opens a research path to explore treat-ment options.  相似文献   

18.
OBJECTIVE: Using predetermined criteria for study quality and methods, a literature review and meta-analysis of seven reports about pediatric bipolar disorder (BPD) was conducted to determine if there is a consistent picture of the phenomenology and clinical characteristics of BPD in children and adolescents. METHODS: Searches were conducted in MedLine and PsycINFO using the terms mania, BPD, children and adolescents, and was limited to published articles in peer-reviewed journals. Seven reports were selected that met the following criteria: a systematic method for the elicitation and reporting of symptoms and clinical characteristics of subjects; subjects were interviewed by a trained researcher or clinician; ages 5-18 years; use of a diagnostic system, either DSM or RDC for categorization; a consensus method for the establishment of the diagnosis of BPD. RESULTS: Most DSM-IV symptoms of mania were common in the children and adolescents with BPD with the most common symptoms being increased energy, distractibility, and pressured speech. On average, four of five bipolar cases also showed threshold levels of irritable mood and grandiosity, and more than 70% of all cases showed elated/euphoric mood, decreased need for sleep, or racing thoughts. Roughly 69% of cases also showed poor judgment, whereas only half of bipolar cases demonstrated flight of ideas, and slightly more than one-third showed hypersexuality or psychotic features. CONCLUSIONS: The clinical picture that emerges is that of children or adolescents with periods of increased energy (mania or hypomania), accompanied by distractibility, pressured speech, irritability, grandiosity, racing thoughts, decreased need for sleep and euphoria/elation.  相似文献   

19.
Ströhle A 《Der Nervenarzt》2003,74(3):279-91; quiz 292
Clinical and preclinical studies have gathered substantial evidence that stress response alterations play a major role in the development of major depression, panic disorder, and post-traumatic stress disorder. The stress response, the hypothalamic pituitary adrenocortical (HPA) system and its modulation by corticotropin-releasing hormones (CRH),corticosteroids,and their receptors, and the roles of natriuretic peptides and neuroactive steroids are described. We review the role of the HPA system in major depression, panic disorder, and post-traumatic stress disorder and its possible relevance for treatment. Impaired glucocorticoid receptor function in major depression is associated with an excessive release of neurohormones such as CRH, to which a number of signs and symptoms characteristic of depression can be ascribed. In panic disorder, a role of central CRH in panic attacks has been suggested. Atrial natriuretic peptide (ANP) is causally involved in sodium lactate-induced panic attacks. Furthermore, preclinical and clinical data on its anxiolytic activity suggest that nonpeptidergic ANP receptor ligands may be potentially useful in the treatment of anxiety disorders. Post-traumatic stress disorder is characterized by a peripheral hyporesponsive HPA system and elevated CRH concentrations in the CSF. This dissociation is probably related to an increased risk of this disorder. We further review recent data that describe an important role of GABA(A)-receptor modulatory,3 alpha-reduced neuroactive steroids in major depression, anxiety, and its treatment. Antidepressants are effective in both depression and anxiety disorders and have major effects on the HPA system,especially on glucocorticoid and mineralocorticoid receptors. Normalization of HPA system abnormalities is a strong predictor of the clinical course, at least in major depression and panic disorder. Currently,CRH-R1 or glucocorticoid receptor antagonists and ANP receptor agonists are being studied and may provide future treatment options more closely related to the pathophysiology of these disorders.  相似文献   

20.
This study evaluates the effects of agonists and antagonists of cholecystokinin (CCK) on contractile and myoelectrical activity in isolated longitudinal muscle strips from colon or ileum of guinea pigs or beagle dogs. Caerulein and CCK-8 caused a dose-dependent increase of contractile and myoelectrical spike activity in both species with maximal effects seen between 10−8 and 3 × 10−8 M. The dose responses were identical for both CCK agonists and species. The dose-related effects of CCK compounds on colonic muscle were slightly shifted to the right when compared to ileum in both species. All antagonists, the proglumide-derivatives CR1409, CR1392, and CR1505, as well as the nonpeptide substances asperlicin and L-364,718, caused a parallel rightward shift of CCK's dose-dependent motor activity response, indicating the competitive nature of inhibition. The antagonists displayed a rank order of potency in antagonizing CCK's action on intestinal motility similar to their ability to antagonize CCK's action on pancreas and gallbladder. L-364,718 was the most potent antagonist, followed by CR1409, CR1505, CR1392, asperlicin, and proglumide. The antagonists did not affect contractile or myoelectrical responses to acetylcholine, histamine, motilin, or substance P. Thus compounds that have been described as CCK antagonists for pancreas and gallbladder also act as specific and competitive antagonists of CCK's action on contractile and myoelectrical activity of Heal and colonie muscle.  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