Bone Tissue Engineering in Rat Calvarial Defects Using Induced Bone-like Tissue by rhBMPs from Immature Muscular Tissues In Vitro

This study aimed to induce bone-like tissue from immature muscular tissue (IMT) in vitro using commercially available recombinant human bone morphogenetic protein (rhBMP)-2, rhBMP-4, and rhBMP-7, and then implanting this tissue into a calvarial defect in rats to assess healing. IMTs were extracted from 20-day-old Sprague-Dawley (SD) fetal rats, placed on expanded polytetrafluoroethylene (ePTFE) with 10 ng/μL each of rhBMP-2, BMP-4, and BMP-7, and cultured for two weeks. The specimens were implanted into calvarial defects in 3-week-old SD rats for up to three weeks. Relatively strong radiopacity was observed on micro-CT two weeks after culture, and bone-like tissue, comprising osteoblastic cells and osteoids, was partially observed by H&E staining. Calcium, phosphorus, and oxygen were detected in the extracellular matrix using an electron probe micro analyzer, and X-ray diffraction patterns and Fourier transform infrared spectroscopy spectra of the specimen were found to have typical apatite crystal peaks and spectra, respectively. Furthermore, partial strong radiopacity and ossification were confirmed one week after implantation, and a dominant novel bone was observed after two weeks in the defect site. Thus, rhBMP-2, BMP-4, and BMP-7 differentiated IMT into bone-like tissue in vitro, and this induced bone-like tissue has ossification potential and promotes the healing of calvarial defects. Our results suggest that IMT is an effective tissue source for bone tissue engineering.     

Polyphenol-Enriched Composite Bone Regeneration Materials: A Systematic Review of In Vitro Studies

One of the possible alternatives for creating materials for the regeneration of bone tissue supporting comprehensive reconstruction is the incorporation of active substances whose controlled release will improve this process. This systematic review aimed to identify and synthesize in vitro studies that assess the suitability of polyphenolics as additives to polymer-ceramic composite bone regeneration materials. Data on experimental studies in terms of the difference in mechanical, wettability, cytocompatibility, antioxidant and anti-inflammatory properties of materials were synthesized. The obtained numerical data were compiled and analyzed in search of percentage changes of these parameters. The results of the systematic review were based on data from forty-six studies presented in nineteen articles. The addition of polyphenolic compounds to composite materials for bone regeneration improved the cytocompatibility and increased the activity of early markers of osteoblast differentiation, indicating a high osteoinductive potential of the materials. Polyphenolic compounds incorporated into the materials presumably give them high antioxidant properties and reduce the production of reactive oxygen species in macrophage cells, implying anti-inflammatory activity. The evidence was limited by the number of missing data and the heterogeneity of the data.     

经向夹衬加强筋机织物及双引纬织造的研究

提出经向夹衬加强筋机织物的结构,介绍其形成原理及方法,并通过实验及讨论,提出双梭口织机引纬、打纬、送经和卷取机构的改造方案。该结构改善了纤维或纱线在织物及其复合材料中的空间分布形态,从而也能加强其物理机械性能,扩大应用领域。     

基于Cult3D的交互式虚拟内耳显微解剖

Cult3D是一个实现基于普通电脑的交互式人体结构三维显示的有效平台。在对内耳结构三维数据处理的基础上，使用Cult3D Designer编辑器，采用组织事件、动作与对象的关联的编程手段实现了对内耳三维对象的复杂交互动作控制，完成基于普通电脑的交互式虚拟内耳显微解剖浏览系统。     

人骨髓间充质干细胞的超微结构

目的：分离培养人骨髓骨充质干细胞，进行超微结构观察。方法：冲洗出流产胎儿股骨髓内容物，梯度离心，取舍有骨髓间充质干细胞的低密度血小板层进行,立春 透射电镜，扫描电镜下进行超微结构的全面观察，结果：透射电镜下可见细胞有两种不同的形态结构，细胞间有许多缝隙连接；扫描电镜下可见细胞表面有短而粗的微绒毛突起，结论：培养的细胞有适宜作为组织工程种子细胞的形态学基础。     

基于改进U-Net的SPECT骨显像病灶分割研究北大核心CSCD

在核医学中,单光子发射计算机断层(single-photon emission computed tomograpy,SPECT)骨显像是辅助医师诊断癌症的重要手段。针对骨显像图像信噪比低、边界模糊、病灶小难以提取和人工勾画病灶耗时等问题,提出一种基于改进U-Net网络的骨显像病灶自动分割算法。该算法在U-Net的原卷积块基础上,采用了多尺度密集连接(multi-scale dense connection,MDC)的方式来提高对小病灶特征的提取能力,同时解决了网络加深后出现的梯度消失问题。其次,为提取病灶的细节特征,在密集连接和跳跃连接处引入了注意力机制结构。最后,针对使用小样本数据集,模型难以收敛的问题,采用迁移学习的方法,优化了模型的初始参数,提升模型的泛化能力和分割效率。此外,为了降低计算量、进一步提高分割效果,对数据集进行了裁剪和去噪。同时,将处理后的图像采用旋转、镜像等方法进行了数据扩充。实验结果表明,改进的U-Net的识别精确率(precision)、平均交并比(mean intersection-over-union,mIoU)分别能达到0.7352、0.4673,效果优于目前主流的分割算法,具有一定实际应用价值。     

颞骨及岩骨段颈内动脉的断面解剖学研究与三维模型构建

目的：为解剖学习和临床影像诊断及手术治疗提供颞骨及岩骨段颈内动脉（petrous carotid artery,PCA）的三维立体形态学参数。方法：该研究中,我们采用数字化可视人（中国首例女性）的数据集（该断层层厚较薄,霞建图像更逼真,数据更精确）,对颞骨及PCA进行断面解剖学观察,提取相关断面图像信息,分别应用Adobe．photoshopCS3、AmiFa和Maya软件。对颞骨及PCA进行计算机三维重建和虚拟现实显示。结果：通过3个典型的层面（即外半规管层面、前庭窗层面、咽鼓管层面）,对其主要结构的断面形态及毗邻关系进行描述。重建三维模型可清楚地显示颢骨内部结构和PCA的形态和空间位置关系,同时尚可任意角度旋转、切割、组合和整体显示相关结构。PCA水平段与PCA弯曲部和内耳道内侧缘连线的夹角平均值为67．5度。结论：采用三维重建技术重建的颢骨及PCA结构清晰,其构建模型可较为准确地揭示颢骨内部结构及与PCA的毗邻关系,为解剖学习和临床应用提供更为直观便捷的参考。     

负载氯喹的骨靶向纳米颗粒打破肿瘤细胞增殖与骨吸收之间的恶性循环

肿瘤细胞增殖与骨吸收之间的恶性循环加剧了骨肿瘤的进展和转移风险.为此,我们设计并制备了聚乙二醇-阿仑膦酸钠修饰的聚多巴胺(PPA)纳米粒子,并在其表面负载自噬抑制剂氯喹(CQ),期望利用该治疗载体(PPA/CQ)打破肿瘤细胞增殖与骨吸收之间的恶性循环,从而有效地治疗骨肿瘤.实验证明,PPA/CQ可以有效地富集到骨组织,...