The advantages of microfluidics to study actin biochemistry and biomechanics

Journal of Muscle Research and Cell Motility - The regulated assembly of actin filaments is essential in nearly all cell types. Studying actin assembly dynamics can pose many technical challenges....     

软骨下骨局部注射常山酮抑制转化生长因子β1信号通路缓解犬骨关节炎

文题释义： Micro-CT：即微型计算机断层扫描,遵循的是与用于医疗的计算机断层扫描相同的原理,但可提供更高分辨率,Micro-CT和高分辨率外周定量计算机断层扫描系统是目前最有用的且拥有高分辨率的骨小梁和皮质骨超微结构成像,目前用于评估骨形态特征,作为传统组织学分析的补充替代方案。 X型胶原蛋白α1链(COL10A1)：为X型胶原蛋白的特异性裂解片段,X型胶原蛋白是软骨细胞肥大分化的典型标志,在骨关节炎进展过程中,软骨细胞肥大及其合成的促炎细胞因子助软骨破坏。 背景：研究表明随着破骨细胞骨吸收的增加,过度激活了的转化生长因子β1使骨吸收和骨形成解偶联,最终导致骨关节炎动物模型中软骨下骨的硬化表型,且可通过抑制转化生长因子β1信号传导减弱骨关节炎的进展。 目的：检测前十字韧带横切比格犬骨关节炎模型中局部注射常山酮是否可以延缓骨关节炎进展。 方法：将18只雄性比格犬分为假手术(对照组)、骨性关节炎组及治疗组,后两组通过前十字韧带横切构建骨关节炎模型,治疗组造模后于软骨下骨局部注射常山酮37.8 ng。在造模术后4,8,12,16周纵向测量血清Ⅱ型胶原C端肽(CTX-Ⅱ)和X型胶原蛋白α1链血清标志物的水平;术后16周Micro-CT扫描观察软骨下骨微结构;番红固绿染色及OARSI-Modified Manking评分评估关节软骨退变程度;免疫组织化学染色对比转化生长因子β1、基质金属蛋白酶13的表达情况。实验方案经新疆医科大学第一附属医院动物实验伦理委员会批准(批准号为IACUC20160304-07)。 结果与结论：①造模后8,12周,骨关节炎组X型胶原蛋白α1链水平高于治疗组和对照组(均P < 0.01);②造模后8,12,16周,骨关节炎组CTX-Ⅱ水平均高于对照组和治疗组(均P < 0.05);③骨关节炎组软骨下骨的骨体积分数较治疗组和对照组增加,骨小梁分离度降低,骨小梁模式因子减小(均P < 0.05);④骨关节炎组OARSI-Modified Manking评分较对照组和治疗组更高(均P < 0.01);⑤骨关节炎组基质金属蛋白酶13及转化生长因子β1的表达量较对照组和治疗组更高(均P < 0.01);⑥对照组与治疗组上述各指标比较差异均无显著性意义(均P > 0.05);⑦结果说明,局部注射常山酮可通过抑制软骨下骨中异常升高的转化生长因子β1,阻断异常骨重塑来减轻前十字韧带横切诱导的骨关节炎,表明这可能是骨关节炎的一种新的治疗选择。 ORCID: 0000-0003-1388-5541(任姜栋) 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

A double commutant theorem for Murray-von Neumann algebras

Murray-von Neumann algebras are algebras of operators affiliated with finite von Neumann algebras. In this article, we study commutativity and affiliation of self-adjoint operators (possibly unbounded). We show that a maximal abelian self-adjoint subalgebra A of the Murray-von Neumann algebra A(f)(R) associated with a finite von Neumann algebra R is the Murray-von Neumann algebra A(f)(A(0)), where A(0) is a maximal abelian self-adjoint subalgebra of R and, in addition, A(0) is A Π R. We also prove that the Murray-von Neumann algebra A(f)(C) with C the center of R is the center of the Murray-von Neumann algebra A(f)(R). Von Neumann's celebrated double commutant theorem characterizes von Neumann algebras R as those for which R' = R, where R', the commutant of R, is the set of bounded operators on the Hilbert space that commute with all operators in R. At the end of this article, we present a double commutant theorem for Murray-von Neumann algebras.     

Homology-independent discovery of replicating pathogenic circular RNAs by deep sequencing and a new computational algorithm

A common challenge in pathogen discovery by deep sequencing approaches is to recognize viral or subviral pathogens in samples of diseased tissue that share no significant homology with a known pathogen. Here we report a homology-independent approach for discovering viroids, a distinct class of free circular RNA subviral pathogens that encode no protein and are known to infect plants only. Our approach involves analyzing the sequences of the total small RNAs of the infected plants obtained by deep sequencing with a unique computational algorithm, progressive filtering of overlapping small RNAs (PFOR). Viroid infection triggers production of viroid-derived overlapping siRNAs that cover the entire genome with high densities. PFOR retains viroid-specific siRNAs for genome assembly by progressively eliminating nonoverlapping small RNAs and those that overlap but cannot be assembled into a direct repeat RNA, which is synthesized from circular or multimeric repeated-sequence templates during viroid replication. We show that viroids from the two known families are readily identified and their full-length sequences assembled by PFOR from small RNAs sequenced from infected plants. PFOR analysis of a grapevine library further identified a viroid-like circular RNA 375 nt long that shared no significant sequence homology with known molecules and encoded active hammerhead ribozymes in RNAs of both plus and minus polarities, which presumably self-cleave to release monomer from multimeric replicative intermediates. A potential application of the homology-independent approach for viroid discovery in plant and animal species where RNA replication triggers the biogenesis of siRNAs is discussed.     

单纯疱疹病毒性脑炎发病机制研究进展

单纯疱疹病毒性脑炎（Herpes simplex virus encephalitis,HSE）又名急性坏死性出血性脑炎,是世界范围内最常见的致死性散发性脑炎,它是由单纯疱疹病毒（Herpes simplex virus,HSV）引起的急性中枢神经系统感染性疾病。HSE的发病机制尚未完全清楚。目前认为,病毒基因ICP34.5产物使机体宿主抗病毒的内源性干扰素系统失效而发挥致病作用[1]。     

Anti-inflammation and antioxidant effect of Cordymin, a peptide purified from the medicinal mushroom Cordyceps sinensis, in middle cerebral artery occlusion-induced focal cerebral ischemia in rats

Cordymin is a peptide purified from the medicinal mushroom Cordyceps sinensis. The present study investigated the effects of Cordymin in prevention of focal cerebral ischemic/reperfusion (IR) injury. The right middle cerebral artery occlusion model was used in the study. The effects of Cordymin on mortality rate, neurobehavior, grip strength, glutathione content, lipid Peroxidation, glutathione peroxidase activity, glutathione reductase activity, catalase activity, Na⁺K⁺ATPase activity glutathione S transferase activity and on the regulation of C3 and C4 protein level, polymorphonuclear cells, interleukin-1β and tumor necrosis factor-α in a rat model were studied respectively. Treatment (orally) of Cordymin significantly boosted the defense mechanism against cerebral ischemia by increasing antioxidants activity related to lesion pathogenesis. Restoration of the antioxidant homeostasis in the brain after reperfusion may have helped the brain recover from ischemic injury. Moreover, Cordymin significantly inhibited infiltration of polymorphonuclear cells and IR-induced up-regulation of the brain production of C3 protein level, interleukin-1β and tumor necrosis factor-α. Cordymin significantly improved the outcome in rats after cerebral ischemia and reperfusion in terms of neurobehavioral function. Our findings suggest that cordymin have a neuroprotective effect in the ischemic brain, which is due to the inhibition of inflammation and increase of antioxidants activity related to lesion pathogenesis. Cordymin can be used as potential preventive agent against cerebral ischemia-reperfusion injury.