Enhanced expressions of arachidonic acid-sensitive tandem-pore domain potassium channels in rat experimental acute cerebral ischemia

To further explore the pathophysiological significance of arachidonic acid-sensitive potassium channels, RT-PCR and Western blot analysis were used to investigate the expression changes of TREK channels in cortex and hippocampus in rat experimental acute cerebral ischemia in this study. Results showed that TREK-1 and TRAAK mRNA in cortex, TREK-1 and TREK-2 mRNA in hippocampus showed significant increases 2 h after middle cerebral artery occlusion (MCAO). While the mRNA expression levels of the all three channel subtypes increased significantly 24 h after MCAO in cortex and hippocampus. At the same time, the protein expressions of all the three channel proteins showed significant increase 24 h after MCAO in cortex and hippocampus, but only TREK-1 showed increased expression 2 h after MCAO in cortex and hippocampus. Immunohistochemical experiments verified that all the three channel proteins had higher expression levels in cortical and hippocampal neurons 24 h after MCAO. These results suggested a strong correlation between TREK channels and acute cerebral ischemia. TREK channels might provide a neuroprotective mechanism in the pathological process.     

CCM3/PDCD10 heterodimerizes with germinal center kinase III (GCKIII) proteins using a mechanism analogous to CCM3 homodimerization

CCM3 mutations give rise to cerebral cavernous malformations (CCMs) of the vasculature through a mechanism that remains unclear. Interaction of CCM3 with the germinal center kinase III (GCKIII) subfamily of Sterile 20 protein kinases, MST4, STK24, and STK25, has been implicated in cardiovascular development in the zebrafish, raising the possibility that dysregulated GCKIII function may contribute to the etiology of CCM disease. Here, we show that the amino-terminal region of CCM3 is necessary and sufficient to bind directly to the C-terminal tail region of GCKIII proteins. This same region of CCM3 was shown previously to mediate homodimerization through the formation of an interdigitated α-helical domain. Sequence conservation and binding studies suggest that CCM3 may preferentially heterodimerize with GCKIII proteins through a manner structurally analogous to that employed for CCM3 homodimerization.     

利用功能磁共振研究记忆功能的研究进展

功能磁共振成像(fMRI)作为一种无创伤,可反复实验的成像技术,已被广泛地应用于各项脑功能的研究。用fMRI进行脑功能研究的主要依据是血流敏感性和BOLD对比增强原理。记忆是人脑的高级功能,其过程分为编码加工、固化、存储和提取几个阶段。大脑皮质、海马、乳头体、丘脑是参与记忆的主要解剖结构。记忆的刺激方式对各个脑区的激活是具有差异性的,记忆功能的测量和分析方法也在不断的改进。年龄和性别的不同都会对记忆能力产生影响,同时激活的脑区也会有相应的改变。此外,情感和记忆的关系正越来越受到人们的关注。本文阐述利用功能磁共振成像研究记忆功能的最新进展。     

丰富环境对脑缺血再灌注小鼠神经细胞凋亡和XIAP基因表达的影响

该研究主要探讨丰富环境干预对脑缺血再灌注小鼠神经细胞凋亡的影响。实验采用健康雄性ICR 小鼠,随机分为丰富环境缺血组(IE)、标准环境缺血组(IS),同时分别设丰富环境假手术组(SE)、标准环境假手术组(SS)。通过双侧颈动脉重复结扎建立小鼠全脑缺血再灌注模型,分别在缺血后在丰富环境和标准环境饲养3 d或7 d 后,进行开场行为和水迷宫空间记忆行为检测;同时进行神经细胞损伤的组织学观测,并采用琼脂糖凝胶电泳技术分析DNA 片段化,用RT-PCR 检测X 染色体连锁的凋亡抑制蛋白（X-linked inhibitor of apoptosis protein,XIAP） mRNA的表达。结果表明,丰富环境干预能有效改善脑缺血导致的自发活动、探究行为减少和空间学习记忆能力减退,并对正常小鼠也有促进作用。缺血再灌注4 d的海马神经细胞损伤较严重,神经元密度显著减少,脑组织DNA 片段化明显增强,丰富环境作用使神经细胞损伤和DNA 片段化程度均有所减轻。同时丰富环境作用可抑制反复脑缺血再灌注导致的XIAP mRNA 表达下调。可见,丰富环境干预可改善脑缺血小鼠的自发活动、探究行为和空间学习记忆能力,该作用可能与其抑制神经细胞XIAP基因表达下调、减弱脑缺血再灌注诱导的神经细胞凋亡有关。     

15-HETE参与的脑缺血再灌注损伤中p-ERK1/2表达变化的研究

目的:通过应用15-脂氧化酶(15-Lipoxygenase,15-LOX)抑制剂去甲二氢愈创木酸(nordihydroguaiaretic acid,NDGA)抑制15-羟基-二十碳四烯酸(15-hydroxyeicosatetraenoic acid,15-HETE)的生成,观察缺血再灌注损伤中大鼠脑组织磷酸化细胞外信号调节酶(phosphor-extracellular signal-regulated kinase,p-ERK1/2)表达的变化,探讨p-ERK1/2在15-HETE参与的脑缺血再灌注损伤中的作用及其表达变化。方法:应用大脑中动脉线栓栓塞法(MCAO)制作大鼠脑梗死2小时再灌注模型。将大鼠随机分为三组:假手术组(sham组)、DMSO对照组、NDGA处理组。后两组再根据不同的灌注时间分为三个亚组:再灌注1小时组、再灌注6小时组、再灌注24小时组。采用TTC染色法检测再灌注24小时大鼠脑梗死体积;免疫印迹(Western blot)法测定梗死后再灌注不同时间点梗死核心区和梗死周围区的p-ERK1/2的表达。结果:假手术组仅有少量p-ERK1/2的表达。DMSO对照组梗死核心区p-ERK1/2的表达从梗死再灌注后1小时即开始逐渐升高(1.43±0.06),6小时达高峰(2.02±0.14),24小时有所下降(1.16±0.21),与假手术组(0.62±0.08)比较P值均0.01;梗死周围区p-ERK1/2表现出相同的变化趋势。与DMSO对照组比较,NDGA处理组大鼠脑梗死体积显著减小(20.10±0.12%vs 17.24±0.16%,P=0.009,P0.05),各时间点p-ERK1/2的表达均下降。与梗死核心区相比较,梗死周围区24小时仍可检测到较高含量的p-ERK1/2(1.16±0.21 vs 1.86±0.14),但梗死核心区表达相对较少。结论:脑缺血再灌注损伤中,p-ERK1/2的表达增加,说明p-ERK1/2参与其中;应用NDGA后,p-ERK1/2的表达降低,脑梗死体积减小,证实p-ERK1/2参与了15-HETE介导的脑缺血再灌注损伤,并在此过程中可能参与了细胞的凋亡。     

通络救脑注射液对大鼠脑微血管内皮细胞活性 及其条件培养液影响的初步研究

目的：观察通络救脑注射液对正常及拟缺血大鼠脑微血管内皮细胞的活性影响,并初步探讨细胞条件培养液内蛋白分泌的时效特征、奠定可溶性蛋白深入分析的技术基础。方法：通络救脑注射液作用于正常夏拟缺血脑微血管内皮细胞之后,用MTS／PMS比色分析法测定细胞的活性,Bradford法测定细胞培养液总蛋白含量,比色分析法测定细胞培养液乳酸脱氢酶（LDH）漏出值,同步观察了5个时间点的细胞活性及条件培养液总蛋白量及LDH释放量。结果：通络救脑注射液能够提高拟缺血细胞的活性,且抑制LDH释放量;正常组分泌总蛋白量3h达到高峰,此时细胞活性最佳,LDH释放量亦少。拟缺血组分泌总蛋白量是6h达到高峰,此时LDH释放量最少,但细胞活性与3h比较有所下降。结论：通络救脑注射液对拟缺血细胞损伤具有保护作用：以3h至6h的细胞条件培养液做为收集目标是研究条件培养液的最佳时间段。     

Newtonian and non-Newtonian blood flow in coiled cerebral aneurysms

Endovascular coiling aims to isolate the aneurysm from blood circulation by altering hemodynamics inside the aneurysm and triggering blood coagulation. Computational fluid dynamics (CFD) techniques have the potential to predict the post-operative hemodynamics and to investigate the complex interaction between blood flow and coils. The purpose of this work is to study the influence of blood viscosity on hemodynamics in coiled aneurysms. Three image-based aneurysm models were used. Each case was virtually coiled with a packing density of around 30%. CFD simulations were performed in coiled and untreated aneurysm geometries using a Newtonian and a Non-Newtonian fluid models. Newtonian fluid slightly overestimates the intra-aneurysmal velocity inside the aneurysm before and after coiling. There were numerical differences between fluid models on velocity magnitudes in coiled simulations. Moreover, the non-Newtonian fluid model produces high viscosity (>0.007$>0.007$ [Pa s]) at aneurysm fundus after coiling. Nonetheless, these local differences and high-viscous regions were not sufficient to alter the main flow patterns and velocity magnitudes before and after coiling. To evaluate the influence of coiling on intra-aneurysmal hemodynamics, the assumption of a Newtonian fluid can be used.     

A2-Pancortins (Pancortin-3 and -4) are the dominant pancortins during neocortical development

We have identified a novel mouse gene named pancortin that is expressed dominantly in the mature cerebral cortex. This gene produces four different species of proteins, Pancortin-1-4, sharing a common region in the middle of their structure with two variations at the N-terminal (A1 or A2 part) and C-terminal (C1 or C2 part) sides, respectively. In the present study, we showed that expression of mRNAs for A2-Pancortins (Pancortin species that contain the A2 part, i.e., Pancortin-3 and -4) is more dominant than that of mRNAs for A1-Pancortins (Pancortin species that contain the A1 part, i.e., Pancortin-1 and -2) in the prenatal mouse cerebral neocortex. Using western blot analysis, we found that substantial amounts of both A2-Pancortins were present in the prenatal cerebral neocortex and P19 cells after inducing neuronal differentiation. A2-Pancortins were still present in the cerebral neocortex of the adult, although their mRNAs were hardly detected. In contrast, the amount of A1-Pancortins did not increase after the third postnatal week in spite of their intense gene expression. Furthermore, we showed that recombinant Pancortin-3, one of the A2-Pancortins, was a secreted protein, in contrast to Pancortin-1 (one of the A1-Pancortins). These results suggest that A2-Pancortins are extracellular proteins essential for neuronal differentiation and that their molecular behavior is distinct from that of A1-Pancortins.     

环闭护理干预对脑出血患者肺部菌群及症状的影响

目的 探讨环闭护理干预对脑出血患者肺部菌群及患者症状的影响,为后续研究提供参考.方法 选取2017年2月至2018年6月我院收治的97例脑出血合并肺部感染患者为研究对象.采用随机数字法将患者分为研究组(n=47)和对照组(n=50).研究组患者行环闭式护理,对照组行常规护理.观察两组患者生活质量、SAS和SDS评分、症...     

Influence of patellar position on the knee extensor mechanism in normal and crouched walking

Patella alta is common in cerebral palsy, especially in patients with crouch gait. Correction of patella alta has been advocated in the treatment of crouch, however the appropriate degree of correction and the implications for knee extensor function remain unclear. Therefore, the goal of this study was to assess the impact of patellar position on quadriceps and patellar tendon forces during normal and crouch gait. To this end, a lower extremity musculoskeletal model with a novel 12 degree of freedom knee joint was used to simulate normal gait in a healthy child, as well as mild (23 deg min knee flexion in stance), moderate (41 deg), and severe (67 deg) crouch gait in three children with cerebral palsy. The simulations revealed that quadriceps and patellar tendon forces increase dramatically with crouch, and are modulated by patellar position. For example with a normal patellar tendon position, peak patellar tendon forces were 0.7 times body weight in normal walking, but reached 2.2, 3.2 and 5.4 times body weight in mild, moderate and severe crouch. Moderate patella alta acted to reduce quadriceps and patellar tendon loads in crouch gait, due to an enhancement of the patellar tendon moment arms with alta in a flexed knee. In contrast, patella baja reduced the patellar tendon moment arm in a flexed knee and thus induced an increase in the patellar tendon loads needed to walk in crouch. Functionally, these results suggest that patella baja could also compromise knee extensor function for other flexed knee activities such as chair rise and stair climbing. The findings are important to consider when using surgical approaches for correcting patella alta in children who exhibit crouch gait patterns.