壳聚糖微球/纳米羟基磷灰石/聚乳酸-羟基乙酸复合支架制备及其蛋白缓释效果:与单纯纳米羟基磷灰石/聚乳酸-羟基乙酸支架、壳聚糖微球的比较

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 μum,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1 00-400 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.     

壳聚糖及其衍生物在骨组织工程中的应用

壳聚糖是天然多糖类高分子化合物甲壳素的脱乙酰产物,具有来源丰富、生物相容性好、可生物降解等优点,在骨组织工程中可以加工成用于细胞移植和组织再生的多孔支架、生长因子的缓释载体及外源基因的递送载体,也可加工成微球或水凝胶等形式用作骨组织工程的可注射性支架,在骨组织工程研究领域壳聚糖及其衍生物具有广阔的应用前景.但由于壳聚糖复合支架的机械性能较弱、在体内的降解时间难以精确控制、壳聚糖用作基因载体转率效率偏低等原因,目前大多研究只处于体外和动物体内实验阶段,随着材料科学与生命科学的发展,壳聚糖将广泛用于骨组织缺损的临床治疗实践中.     

电纺丝聚乳酸、聚3羟基丁酸酯共聚4羟基丁酸酯和聚碳酸亚丙酯纳米纤维的制备及表面亲水性(英文)

背景:近年来聚乳酸、羟基磷灰石类复合材料支架具有良好的生物降解性和生物相容性而被广泛的研究,但是这类复合材料在增强材料界面的结合、调节材料的降解速率、改善材料的强度等方面仍不能满足理想的组织工程支架材料的要求.目的:探讨电纺丝法制备纳米纤维的结构形态及表面亲水性.方法:分别将聚乳酸、聚3羟基丁酸酯共聚4羟基丁酸酯和聚碳酸亚丙酯通过静电纺丝法制备纳米纤维膜,扫描电镜对纤维膜的结构形态进行分析,并观察在人体环境相近的磷酸盐缓冲溶液(37℃,pH 7.4)中浸泡不同时间的表面亲水性.结果与结论:通过静电纺丝技术可以将聚乳酸、聚3羟基丁酸酯共聚4羟基丁酸酯和聚碳酸亚丙酯3种材料制各成微纳米纤维结构,控制制备参数可以获得不同直径的纤维,样品随着在培养液中的浸泡时间延长,总体显示出接触角比初始降低,亲水性增强.     

胶质细胞源性神经营养因子缓释微球及NogoA,ChABC缓释微球联合应用损伤脊髓再生的形态学变化

背景:促进轴突再生的原则是改善抑制再生的环境和提高轴突生长能力,措施主要有轴突生长抑制因子阻滞剂和神经营养因子应用。用可降解微球加载药物是一种在局部提供持续药物释放的方法。目的:探讨胶质细胞源性神经营养因子、NogoA、ChABC缓释微球联合应用促进大鼠损伤脊髓再生病理形态学修复的作用。方法:建立SD大鼠T10脊髓完全横断伤模型,分别在损伤局部给予生理盐水、胶质细胞源性神经营养因子、胶质细胞源性神经营养因子缓释微球、NogoA缓释微球、ChABC缓释微球及3种微球联合治疗,并设立未造模的正常组及假手术组。损伤后10周,每组行四甲基若丹明葡聚糖胺顺行示踪,及神经丝蛋白200、生长相关蛋白43、胶质细胞源性神经营养因子免疫组化检查,并采用免疫组化图像分析系统进行定量分析。结果与结论:胶质细胞源性神经营养因子、NogoA、ChABC缓释微球联合能提高脊髓损伤局部神经丝蛋白200、生长相关蛋白43、胶质纤维酸性蛋白的表达水平,显示局部脊髓再生修复加强,其效果优于单用胶质细胞源性神经营养因子缓释微球。提示,胶质细胞源性神经营养因子缓释微球及NogoA,ChABC缓释微球联合促大鼠损伤脊髓再生修复其效果优于单用胶质细胞源性神经营养因子缓释微球。     

胶质细胞源性神经营养因子缓释微球及NogoA,ChABC缓释微球联合应用损伤脊髓再生的形态学变化

背景：促进轴突再生的原则是改善抑制再生的环境和提高轴突生长能力,措施主要有轴突生长抑制因子阻滞剂和神经营养因子应用。用可降解微球加载药物是一种在局部提供持续药物释放的方法。目的：探讨胶质细胞源性神经营养因子、NogoA、ChABC缓释微球联合应用促进大鼠损伤脊髓再生病理形态学修复的作用。方法：建立SD大鼠T10脊髓完全横断伤模型,分别在损伤局部给予生理盐水、胶质细胞源性神经营养因子、胶质细胞源性神经营养因子缓释微球、NogoA缓释微球、ChABC缓释微球及3种微球联合治疗,并设立未造模的正常组及假手术组。损伤后10周,每组行四甲基若丹明葡聚糖胺顺行示踪,及神经丝蛋白200、生长相关蛋白43、胶质细胞源性神经营养因子免疫组化检查,并采用免疫组化图像分析系统进行定量分析。结果与结论：胶质细胞源性神经营养因子、NogoA、ChABC缓释微球联合能提高脊髓损伤局部神经丝蛋白200、生长相关蛋白43、胶质纤维酸性蛋白的表达水平,显示局部脊髓再生修复加强,其效果优于单用胶质细胞源性神经营养因子缓释微球。提示,胶质细胞源性神经营养因子缓释微球及NogoA,ChABC缓释微球联合促大鼠损伤脊髓再生修复其效果优于单用胶质细胞源性神经营养因子缓释微球。     

聚左旋乳酸/壳聚糖电纺丝纳米纤维支架与兔内皮祖细胞的生物相容性

背景：电纺丝技术能够使许多高分子材料制备出与细胞外基质相似的三维纳米纤维支架。聚乳酸/壳聚糖纳米纤维复合支架材料能够克服材料的不足,提高组织工程支架生物相容性。目的：评价聚左旋乳酸/壳聚糖电纺丝纳米纤维支架与兔内皮祖细胞的生物相容性。方法：电纺丝技术制备聚左旋乳酸,壳聚糖,聚左旋乳酸/壳聚糖的纳米纤维支架,扫描电镜观察其形貌结构。纳米纤维支架与内皮祖细胞进行复合培养后,观察细胞在不同材料上的黏附率、一氧化氮分泌,生长特征和在聚左旋乳酸/壳聚糖纳米纤维支架上的细胞表型特征。结果与结论：聚左旋乳酸/壳聚糖纳米纤维支架比聚左旋乳酸、壳聚糖具有更合适的纤维直径,具有与细胞外基质相似的纳米纤维三维多孔结构。聚左旋乳酸/壳聚糖纳米纤维支架能够促进内皮祖细胞黏附率和细胞的一氧化氮分泌（P〈0.05,P〈0.01）。内皮祖细胞能够在聚左旋乳酸/壳聚糖复合材料膜上融合成片,保持了细胞的完整形态和分化功能,显示了内皮细胞特异性的vWF表型。提示聚左旋乳酸/壳聚糖电纺丝纳米纤维支架与兔内皮祖细胞具有良好的生物相容性。     

人同种异体骨载异烟肼-壳聚糖缓释微球的制备和体内外释药特性

背景：壳聚糖微球具有良好的生物相容性及抗菌活性,被广泛地运用于各种药物缓释系统中。目的：制备人同种异体骨载异烟肼-壳聚糖微球,并分析其体内释药性能。方法：用喷雾干燥法制备异烟肼-壳聚糖微球,进行体外45d的药物释放实验。将单独装载异烟肼的异体骨块（对照组）和装载异烟肼-壳聚糖微球的异体骨块（实验组）分别植入家兔两侧髂骨,采用高效液相色谱法检测药物体内释放情况。结果与结论：异烟肼-壳聚糖微球外观呈圆形、表面光滑、分散良好;平均粒径（3.33±0.9）μm,载药率（16.25±1.24）%。体外药物释放实验显示无突释现象,24h释放20%左右,45d释放76%,释放曲线较平缓,释放稳定;数学模型拟合符合Ritger-Peppas模型。实验组异烟肼浓度在前28d内缓慢升高,其后缓慢下降,持续56d以上,浓度38.50～155.75μg/g;对照组异烟肼浓度在1周左右达高峰,为1982.5μg/g,21d后骨块周围药物不能测到。说明异烟肼-壳聚糖缓释微球在体内外均可以缓慢平稳释放异烟肼,且持续时间长。提示人同种异体骨载异烟肼-壳聚糖缓释微球复合体可以作为骨结核病灶清除后的一种置入材料,在提供机械支持的同时进行长时间的局部化疗。     

人同种异体骨载异烟肼-壳聚糖缓释微球的制备和体内外释药特性

背景:壳聚糖微球具有良好的生物相容性及抗菌活性,被广泛地运用于各种药物缓释系统中。目的:制备人同种异体骨载异烟肼-壳聚糖微球,并分析其体内释药性能。方法:用喷雾干燥法制备异烟肼-壳聚糖微球,进行体外45d的药物释放实验。将单独装载异烟肼的异体骨块(对照组)和装载异烟肼-壳聚糖微球的异体骨块(实验组)分别植入家兔两侧髂骨,采用高效液相色谱法检测药物体内释放情况。结果与结论:异烟肼-壳聚糖微球外观呈圆形、表面光滑、分散良好;平均粒径(3.33±0.9)μm,载药率(16.25±1.24)%。体外药物释放实验显示无突释现象,24h释放20%左右,45d释放76%,释放曲线较平缓,释放稳定;数学模型拟合符合Ritger-Peppas模型。实验组异烟肼浓度在前28d内缓慢升高,其后缓慢下降,持续56d以上,浓度38.50～155.75μg/g;对照组异烟肼浓度在1周左右达高峰,为1982.5μg/g,21d后骨块周围药物不能测到。说明异烟肼-壳聚糖缓释微球在体内外均可以缓慢平稳释放异烟肼,且持续时间长。提示人同种异体骨载异烟肼-壳聚糖缓释微球复合体可以作为骨结核病灶清除后的一种置入材料,在提供机械支持的同时进行长时间的局部化疗。     

季铵盐壳聚糖三维支架复合GNDF载间充质干细胞向神经样细胞分化

背景：壳聚糖类水凝胶因其良好的生物相容性、可降解性及对药物的缓释作用,作为支架材料近年来在组织损伤修复领域逐渐成为研究热点。 目的：探索大鼠骨髓间充质干细胞在季铵盐壳聚糖温敏凝胶支架上生长、向神经样细胞定向分化的可行性,为治疗神经系统损伤寻找理想的组织工程材料。 方法：季铵盐壳聚糖与β-甘油磷酸钠复合制成温敏凝胶,扫描电镜观察凝胶的三维结构,MTT法评价凝胶浸提液对骨髓间充质干细胞活力的影响;将牛血清白蛋白加载于凝胶支架,紫外光谱吸收法分析凝胶支架对牛血清白蛋白的缓释效果。接种大鼠骨髓间充质干细胞于凝胶支架,扫描电镜观察在支架缓释胶质细胞源性神经营养因子作用下,骨髓间充质干细胞的生长、分化情况,免疫荧光技术检测神经元烯醇化酶的表达。 结果与结论：季铵盐化壳聚糖与甘油磷酸钠复合所得凝胶支架,其多孔性特点明显,有温敏特性,对蛋白的缓释效果良好,承载大鼠骨髓间充质干细胞后,对其增殖无明显不利影响。在凝胶支架缓释的胶质细胞源性神经营养因子作用下,骨髓间充质干细胞呈现神经样细胞形态,表达神经元特异性标记物神经元烯醇化酶。说明季铵盐壳聚糖温敏凝胶对胶质细胞源性神经营养因子的缓释效果良好,其凝胶支架具有多孔径、良好生物相容性特点,可承载大鼠骨髓间充质干细胞体外生长和向神经元定向分化。     

包裹转化生长因子β1壳聚糖缓释微球的研制

目的:制备包裹转化生长因子β1的壳聚糖微球,并分析其各种特性.方法:将壳聚糖溶解在2%乙酸中,利用吐温-80作为乳化剂,多聚磷酸钠作为交联剂,以乳化交联法制备载有转化生长因子β1的壳聚糖微球;同时制作空壳聚糖微球以及包裹牛血清白蛋白的壳聚糖微球作为空白对照和实验对照.对获得的3种冻干微球的形态,直径大小进行观察,对转化生长因子β1壳聚糖微球的分散情况及所载药物的体外释放情况进行检测,并测定空壳聚糖微球及包裹牛血清白蛋白壳聚糖微球的吸水膨胀率.结果:冻干后的微球经过扫描电镜观察后发现:空壳聚糖微球直径约15 μm,表面光滑,有较多微小孔隙,而包裹了牛血清白蛋白及转化生长因子β1的壳聚糖缓释微球直径约为1 μm,大小较均一,表面光滑.包裹了转化生长因子β1的壳聚糖微球在释放实验中前12 h内释放速度较快,随后趋于平缓.6 d内微球的转化生长因子β1释放率为53.5%.壳聚糖微球及包裹了牛血清白蛋白的壳聚糖微球在1 h后增加的质量基本达到平衡,均超过700%,且发现微球越是在酸性环境中,吸水膨胀率越高.结论:实验采用乳化交联法制备包裹转化生长因子β1的壳聚糖缓释微球的方法简单易行,成球性好,得率高,具有良好的缓释效果.且壳聚糖微球的超强吸水膨胀率对软骨组织工程支架提出了孔径大小及强度的要求.     

Guns and Knives in New Mexico: Patterns of Penetrating Trauma, 1978–1993

Objective: To identify patterns of nonfatal and fatal penetrating trauma among children and adults in New Mexico using ED and medical examiner data.
Methods: The authors retrospectively sampled in 5-year intervals all victims of penetrating trauma who presented to either the state Level-1 trauma center or the state medical examiner from a 16-year period (1978–1993). Rates of nonfatal and fatal firearm and stabbing injury were compared for children and adults.
Results: Rates of nonfatal injury were similar (firearm, 34.3 per 100,000 person-years; stabbing, 35.1). However, rates of fatal injury were significantly different (firearm, 21.9; stabbing, 2.7; relative risk: 8.2; 95% confidence interval: 5.4, 12.5). From 1978 to 1993, nonfatal injury rates increased for children (p = 0.0043) and adults (p < 0.0001), while fatal penetrating injury remained constant. The increase in nonfatal injury in children resulted from increased firearm injury rates. In adults, both stabbing and firearm nonfatal injury rates increased.
Conclusions: Nonfatal injury data suggest that nonfatal violence has increased; fatal injury data suggest that violent death rates have remained constant. Injury patterns vary by age, mechanism of trauma, and data source. These results suggest that ED and medical examiner data differ and that both are needed to guide injury prevention programs.     

Dissociable correlates of two classes of retrieval processing in prefrontal cortex

Although substantial evidence suggests that the prefrontal cortex (PFC) implements processes that are critical for accurate episodic memory judgments, the specific roles of different PFC subregions remain unclear. Here, we used event-related functional magnetic resonance imaging to distinguish between prefrontal activity related to operations that (1) influence processing of retrieval cues based on current task demands, or (2) are involved in monitoring the outputs of retrieval. Fourteen participants studied auditory words spoken by a male or female speaker and completed memory tests in which the stimuli were unstudied foil words and studied words spoken by either the same speaker at study, or the alternate speaker. On "general" test trials, participants were to determine whether each word was studied, regardless of the voice of the speaker, whereas on "specific" test trials, participants were to additionally distinguish between studied words that were spoken in the same voice or a different voice at study. Thus, on specific test trials, participants were explicitly required to attend to voice information in order to evaluate each test item. Anterior (right BA 10), dorsolateral prefrontal (right BA 46), and inferior frontal (bilateral BA 47/12) regions were more active during specific than during general trials. Activation in anterior and dorsolateral PFC was enhanced during specific test trials even in response to unstudied items, suggesting that activation in these regions was related to the differential processing of retrieval cues in the two tasks. In contrast, differences between specific and general test trials in inferior frontal regions (bilateral BA 47/12) were seen only for studied items, suggesting a role for these regions in post-retrieval monitoring processes. Results from this study are consistent with the idea that different PFC subregions implement distinct, but complementary processes that collectively support accurate episodic memory judgments.     

Systematic Reviews Published in the January 2011 Issue of The Cochrane Library

ABSTRACT

The Cochrane Library of Systematic Reviews is published quarterly as a DVD and monthly online. The January 2011 issue (first quarterly DVD for 2011) contains 4515 complete reviews, 1985 protocols for reviews in production, and 13,521 one-page summaries of systematic reviews published in the general medical literature. In addition, there are citations of 641,000 randomized controlled trials, and 14,018 cited papers in the Cochrane methodology register. The health technology assessment database contains over 9300 citations. One hundred and seven new reviews have been published in the last 3 months, of which five have potential relevance for practitioners in pain and palliative medicine.     

Interprofessional approaches to creating safe,high quality health care

Three supplementary perspectives are presented arguing that interprofessional collaboration is both necessary and desirable. Nonetheless, there are often too many serious intra-professional barriers and obstacles to interprofessional collaboration to make it successful. Some of these barriers, it is argued and illustrated, are found in the multiple ways in which professional identity is tacitly acquired and embodied in the practitioners' habitual, everyday practice. The paper then explores ways in which reflection, especially Second order reflection, can help to elucidate and overcome these obstacles, as well as increasing professional adaptability and competence.     

Modified micro-superior percutaneously-assisted total hip: early experiences & case reports

Because of the extensile nature and familiarity of the standard posterior-lateral approach to the hip, a family of "micro-posterior" approaches has been developed. This family includes the Percutaneously-Assisted Total Hip (PATH) approach, the Supercapsular (SuperCap) approach and a newer hybrid approach, the Supercapsular Percutaneously-Assisted Total Hip (SuperPATH) approach. Such approaches should ideally provide a continuum for the surgeon: from a "micro" (external rotator sparing) posterior approach, to a "mini" (external rotator sacrificing) posterior approach, to a standard posterior approach. This could keep a surgeon within his comfort zone during the learning curve of the procedure, while leaving options for complicated reconstructions for the more practiced micro-posterior surgeons. This paper details one author's experiences utilizing this combined approach, as well as permutations of this entire micro-posterior family of approaches as applied to more complex hip reconstructions.     

Prise en charge des entorses externes de cheville : étude clinique préliminaire sur l’efficacité du dispositif Myolux™

Ankle sprains are the most common injury of the musculoskeletal system and are associated with significant societal and economic impacts. It has been proven that classical therapeutic strategies may not be effective in preventing recurrent injuries: the recurrence rates reported in the literature can reach 73%. In order to provide an effective rehabilitation solution, a destabilizing orthosis was developed. This device is equipped with a mechanical articulator reproducing the subtalar mechanics and placed under the heel. In this paper, we present the main results of a preliminary clinical study conducted between 2004 and 2007. All subjects included in this study were treated with the abovementioned orthosis during 10 rehabilitation sessions of 30 minutes each. Data show a relatively low recurrence rate of 12% for the overall population. Moreover, it's of primary importance to note that this satisfactory ratio is largely reduced (3% of recurrence rate) for the 29 patients who performed one training session per month after the 10th initial rehabilitation sessions. Hence, the destabilizing orthosis appears to be an effective solution to prevent recurrent ankle sprains. However, joint protection requires long-term and regular training sessions. This result has motivated the development of a similar device allowing patients to perform training sessions at home. Finally, data obtained in this study are promising awaiting the final results of the comparative, multicentric and independent clinical trials currently managed by the Hospices Civils de Lyon.     

Determination of creatine kinase isoenzyme MB activity in serum using immunological inhibition of creatine kinase M subunit activity. Activity kinetics and diagnostic significance in myocardial infarction.

This is a new method for the determination of creatine kinase isoenzyme MB activity in serum. The method uses direct activity measurement of creatine kinase B subunit activity after blocking of CK-M subunit activity by inhibiting antibodies. The test takes no longer than 15 min. The method yields an intra-serial C.V. of 2.0-12.9%, and a C.V. from day to day of 5.5%. The detection limit is 3.4 U/l creatine kinase MB. In the 95 cases with proven myocardial infarction several types of creatine kinase MB activity kinetics could be determined. The percentage of creatine kinase MB of peak CK-total is 6-25%, with a mean of 11.1%. The amount of creatine kinase MB with respect to total CK activity after reinfarction is higher than the amount after initial infarction.