脱细胞基质面神经修复材料的制备

目的 制备具有天然神经组织结构的支架,构建组织工程化面神经用于修复面神经损伤。方法 取家兔面神经,改良化学萃取法制备脱细胞神经基质,HE染色形态学观察去细胞及脱髓鞘情况,荧光分光光度计测定支架内细胞经Quant-iT PicoGreen工作液染色后的DNA含量。MTT法检测细胞在支架上的相对生长率从而检测支架的细胞毒性。结果 支架移植体呈圆柱形,弹性与正常神经基本一致,组织观察显示细胞结构未见残余完整细胞及细胞碎片残留,未见神经髓鞘及轴突结构,细胞外基质形成纵向排列结构,结构之间可见空隙。兔脱细胞面神经基质支架内残留的DNA含量较正常兔面神经明显下降(P<0.01)。神经基质供体无细胞毒性。结论 改良化学萃取法可有效去除面神经细胞,天然结构保存完好,细胞毒性低,可作为组织工程化面神经的支架。     

Investigation of the Optimal Parameters of Median Nerve Stimulation Using a Variety of Stimulation Methods and Its Effects on Heart Rate Variability: A Systematic Review

ObjectivesThere is a wealth of literature supporting the use of median nerve stimulation (MNS) for modulating autonomic nervous system (ANS) dysfunction such as in hypoxia, recovery after heart valve replacement, ischemia, and cardiac contractibility. Heart rate variability (HRV) is considered a gold standard for measuring autonomic modulation and dynamic nonlinear ANS processes through the use of an electrocardiogram (ECG). Although the use of MNS on HRV in animals and humans has been documented, optimal stimulation parameters are yet to be outlined.Materials and MethodsThis review aims to synthesize findings of neurostimulation using MNS on animals and humans while observing HRV using an ECG. Using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines with search parameters of “Median nerve stimulation,” “Neiguan,” “PC-6,” “HRV,” “Heart rate variability,” and “Heart-rate variability” observing on animals and human subjects, we found a total of 17 eligible articles.ResultsIn this review, changing two parameters, that is, stimulation frequency and side of stimulation, appears to be the most influential in effecting frequency-domain ECG analysis of HRV. However, it is evident from this review that to perform an effective comparison of the effects of MNS on HRV, more detailed reports of the studies are required.ConclusionsFinding the optimal stimulation parameters for MNS is crucial for improving HRV. This will in turn contribute to normalizing ANS function impaired in numerous clinical conditions, such as epilepsy or diabetes.     

海沙瑞林对慢性心力衰竭大鼠心交感神经重构的影响*

目的：探讨海沙瑞林对慢性心力衰竭（ CHF）大鼠心交感神经重构的影响。 方法： SD大鼠随机分为对照 组（ Control 组）、假手术组（ Sham组）、心力衰竭组（ HF组）和海沙瑞林干预组（ HF+Hx 组），应用冠状动脉结 扎法制作CHF大鼠模型，HF+Hx 组大鼠连续4 周尾静脉注射海沙瑞林 100 μg·kg-1·d-1，其他3 组注射等量的生 理盐水。超声心动图测量左心室功能；H-E 染色及Masson 染色观察各组大鼠心肌病理结构变化；免疫组织化学和 免疫印迹检测脑钠肽（ BNP）、神经生长因子（ NGF）、酪氨酸羟化酶（TH）和生长相关蛋白43（ GAP43）表达。 结果：海沙瑞林干预升高CHF大鼠左室射血分数，改善左心室功能，减轻HF组心肌损伤结构病理改变，降低心 肌细胞内BNP 表达，增加NGF、TH和GAP43 表达，差异均具有统计学意义。 结论：CHF大鼠存在心交感神经重构， 海沙瑞林通过改变心交感神经重构， 改善心功能和CHF的预后可能是其实现心保护的机制之一。     

Measuring conduction velocity distributions in peripheral nerves using neurophysiological techniques

ObjectiveTo determine how long it takes for neural impulses to travel along peripheral nerve fibers in living humans.MethodsA collision test was performed to measure the conduction velocity distribution of the ulnar nerve. Two stimuli at the distal and proximal sites were used to produce the collision. Compound muscle or nerve action potentials were recorded to perform the measurements on the motor or mixed nerve, respectively. Interstimulus interval was set at 1–5 ms. A quadri-pulse technique was used to measure the refractory period and calibrate the conduction time.ResultsCompound muscle action potential produced by the proximal stimulation started to emerge at the interstimulus interval of about 1.5 ms and increased with the increment in interstimulus interval. Two groups of motor nerve fibers with different conduction velocities were identified. The mixed nerve showed a wider conduction velocity distribution with identification of more subgroups of nerve fibers than the motor nerve.ConclusionsThe conduction velocity distributions in high resolution on a peripheral motor and mixed nerve are different and this can be measured with the collision test.SignificanceWe provided ground truth data to verify the neuroimaging pipelines for the measurements of latency connectome in the peripheral nervous system.     

MicroRNA-181c provides neuroprotection in an intracerebral hemorrhage model

Apoptosis is an important factor during the early stage of intracerebral hemorrhage.MiR-181 c plays a key regulatory role in apoptosis.However,whether miR-181 c is involved in apoptosis of prophase cells after intracerebral hemorrhage remains unclear.Therefore,in vitro and in vivo experiments were conducted to test this hypothesis.In vivo experiments:collagenase type VII was injected into the basal ganglia of adult Sprague-Dawley rats to establish an intracerebral hemorrhage model.MiR-181 c mimic or inhibitor was injected in situ 4 hours after intracerebral hemorrhage.Neurological functional defects(neurological severity scores)were assessed 1,7,and 14 days after model establishment.Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling and western blot assay were conducted 14 days after model establishment.In vitro experiments:PC12 cells were cultured under oxygen-glucose deprivation,and hemins were added to simulate intracerebral hemorrhage in vitro.MiR-181 c mimic or inhibitor was added to regulate miR-181 c expression.3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay,luciferase reporter system,and western blot assay were performed.Experimental results revealed differences in miR-181 c expression in brain tissues of both patients and rats with cerebral hemorrhage.In addition,in vitro experiments found that miR-181 c overexpression could upregulate the Bcl-2/Bax ratio to inhibit apoptosis,while inhibition of miR-181 c expression could reduce the Bcl-2/Bax ratio and aggravate apoptosis of cells.Regulation of apoptosis occurred through the phosphoinositide 3 kinase(PI3 K)/Akt pathway by targeting of phosphatase and tensin homolog deleted on chromosome ten(PTEN).Higher miR-181 c overexpression correlated with lower neurological severity scores,indicating better recovery of neurological function.In conclusion,miR-181 c affects the prognosis of intracerebral hemorrhage by regulating apoptosis,and these effects might be directly mediated and regulated by targeting of the PTEN\PI3 K/Akt pathway and Bcl-2/Bax ratio.Furthermore,these results indicated that miR-181 c played a neuroprotective role in intracerebral hemorrhage by regulating apoptosis of nerve cells,thus providing a potential target for the prevention and treatment of intracerebral hemorrhage.Testing of human serum was authorized by the Ethics Committee of China Medical University(No.2012-38-1)on February 20,2012.The protocol was registered with the Chinese Clinical Trial Registry(Registration No.ChiCTR-COC-17013559).The animal study was approved by the Institutional Animal Care and Use Committee of China Medical University(approval No.2017008)on March 8,2017.     

Inter-ocular asymmetry of retinal parameters in Caucasian healthy children and young adults measured with optical coherence tomography

AIM: To evaluate retinal parameters in a sample of healthy young Caucasian adults to define the normal or physiological range of inter-ocular asymmetry in this particular age and ethnic group. METHODS: Study sample consisted of 37 Caucasian children and young adults aged between 12 and 23y (spherical equivalent from -3.00 D to +4.00 D, anisometropia <0.5 D and axial length differences <0.3 mm). Normal inter-ocular asymmetry values were determined and 95% inter-ocular difference tolerance values were obtained. RESULTS: Statistically significant inter-ocular differences were found in mean (P=0.003) and superior (P=0.008) retinal nerve fiber layer (RNFL) thickness, as well as in central macular thickness (P=0.039), with larger values in the left eye in all instances, and with tolerance limits of inter-ocular asymmetry of -9.00 μm to 6.00 μm, -28.00 μm to 9 μm and -39.00 μm to 29.00 μm, respectively. In addition, statistically significant differences were found between males and females in mean thickness of the RNFL in the right eye (P=0.020). CONCLUSION: The exploration of the normal asymmetries of the retina may be an effective approach to further understand myopia onset and progression, which is particularly relevant in this age group. Differences in instrumentation and sample characteristics compromise direct comparison with published research and warrant the need for further studies.