The irre Cell Recognition Module (IRM) Protein Kirre Is Required to Form the Reciprocal Synaptic Network of L4 Neurons in the Drosophila Lamina

Each neuropil module, or cartridge, in the fly's lamina has a fixed complement of cells. Of five types of monopolar cell interneurons, only L4 has collaterals that invade neighboring cartridges. In the proximal lamina, these collaterals form reciprocal synapses with both the L2 of their own cartridge and the L4 collateral branches from two other neighboring cartridges. During synaptogenesis, L4 collaterals strongly express the cell adhesion protein Kirre, a member of the irre cell recognition module (IRM) group of proteins (, J Neurogenet, 23, 48–67). The authors show by mutant analysis and gene knockdown techniques that L4 neurons develop their lamina collaterals in the absence of this cell adhesion protein. Using electron microscopy (EM), the authors demonstrate, however, that without Kirre protein these L4 collaterals selectively form fewer synapses. The collaterals of L4 neurons of various genotypes reconstructed from serial-section EM revealed that the number of postsynaptic sites was dramatically reduced in the absence of Kirre, almost eliminating any synaptic input to L4 neurons. A significant reduction of presynaptic sites was also detected in kirre⁰ mutants and gene knockdown flies using RNA interference. L4 neuron reciprocal synapses are thus almost eliminated. A presynaptic marker, Brp-short^GFP confirmed these data using confocal microscopy. This study reveals that removing Kirre protein specifically disrupts the functional L4 synaptic network in the Drosophila lamina.     

适用于脑部电阻抗断层成像的单源驱动电流模式

目的: 寻求一种更适合于脑部电阻抗断层成像技术(EIT)的单源驱动模式. 方法: 针对脑部电阻率分布的特点和数据采集系统的实际情况,在一个由7300多个电阻构成的脑部电阻率分布等效电路模型上,对比了邻近、交叉、对向和新提出的准对向这四种驱动模式在动态范围、独立测量数、边界电压变化量和抗噪性能等方面的差异.结果:除动态范围外,准对向驱动模式均为最优,对向和交叉驱动模式次之,邻近模式最差.结论: 准对向驱动模式最适合于脑部EIT使用.     

放射诱导HSV-TK基因在肺癌细胞中靶向、高效性表达的研究

目的 构建放射诱导的同步放大基因电路,通过基因电路调控HSV-TK基因在肺癌细胞中靶向、高效性表达,以提高放射-基因治疗的有效性和靶向性.方法 利用分子克隆的方法将HSV-TK基因插入到同步放大基因电路载体的下游,并采用脂质体介导重组载体和对照载体转染肺癌细胞A549;G418筛选阳性克隆,转染细胞给予2Gy X线照射后,检测照射前后不同时相点细胞内TK表达情况,及不同浓度前药GCV对转染重组载体和对照载体的肺癌细胞的生长抑制率.结果 照射后转染同步放大重组载体的细胞内TK的表达明显强于对照组,且随时间的推移而逐渐增强,以照射后16h最为明显.同一浓度的GCV对转染同步放大载体的A549细胞的抑制率明显高于对照组和未转染组,IC50也明显低于对照组和未转染组.结论 同步放大基因电路明显增强了靶细胞内HSV-TK基因的表达,进一步完善了放射-基因治疗这一新的肿瘤治疗模式.     

Depletion of microglia in developing cortical circuits reveals its critical role in glutamatergic synapse development,functional connectivity,and critical period plasticity

Microglia populate the early developing brain and mediate pruning of the central synapses. Yet, little is known on their functional significance in shaping the developing cortical circuits. We hypothesize that the developing cortical circuits require microglia for proper circuit maturation and connectivity, and as such, ablation of microglia during the cortical critical period may result in a long-lasting circuit abnormality. We administered PLX3397, a colony-stimulating factor 1 receptor inhibitor, to mice starting at postnatal day 14 and through P28, which depletes >75% of microglia in the visual cortex (VC). This treatment largely covers the critical period (P19-32) of VC maturation and plasticity. Patch clamp recording in VC layer 2/3 (L2/3) and L5 neurons revealed increased mEPSC frequency and reduced amplitude, and decreased AMPA/NMDA current ratio, indicative of altered synapse maturation. Increased spine density was observed in these neurons, potentially reflecting impaired synapse pruning. In addition, VC intracortical circuit functional connectivity, assessed by laser scanning photostimulation combined with glutamate uncaging, was dramatically altered. Using two photon longitudinal dendritic spine imaging, we confirmed that spine elimination/pruning was diminished during VC critical period when microglia were depleted. Reduced spine pruning thus may account for increased spine density and disrupted connectivity of VC circuits. Lastly, using single-unit recording combined with monocular deprivation, we found that ocular dominance plasticity in the VC was obliterated during the critical period as a result of microglia depletion. These data establish a critical role of microglia in developmental cortical synapse pruning, maturation, functional connectivity, and critical period plasticity.     

中性点不接地系统接地故障的探讨

中性点不接地系统的接地故障是变配电系统中比较常见的故障现象,对于故障的处理快慢,也决定着以故障现象转变的事故的可能性大小,所以,对这种故障发生及处理过程必须安全、严谨、高效、准确。     

失效模式与效应分析在床边监护仪报警管理的应用

目的降低床边监护仪使用过程中的潜在风险,提高护理质量,确保患者安全。方法对5个监护病区60张床位的床边监护仪报警管理,运用失效模式与效应分析(FMEA)对使用流程进行分析,查找每个环节中可能存在的风险,针对操作流程、规范培训、质量监管等关键环节实施改进措施。结果实施FMEA管理后,床边监护仪报警管理质量检查结果、护士监护仪使用相关知识掌握评分与实施前比较,差异有统计学意义(均P0.01)。结论对床边监护仪报警运用FMEA管理,能降低床边监护仪不报警的风险,保障患者安全。     

A comprehensive knowledge base of synaptic electrophysiology in the rodent hippocampal formation

The cellular and synaptic architecture of the rodent hippocampus has been described in thousands of peer‐reviewed publications. However, no human‐ or machine‐readable public catalog of synaptic electrophysiology data exists for this or any other neural system. Harnessing state‐of‐the‐art information technology, we have developed a cloud‐based toolset for identifying empirical evidence from the scientific literature pertaining to synaptic electrophysiology, for extracting the experimental data of interest, and for linking each entry to relevant text or figure excerpts. Mining more than 1,200 published journal articles, we have identified eight different signal modalities quantified by 90 different methods to measure synaptic amplitude, kinetics, and plasticity in hippocampal neurons. We have designed a data structure that both reflects the differences and maintains the existing relations among experimental modalities. Moreover, we mapped every annotated experiment to identified potential connections, that is, specific pairs of presynaptic and postsynaptic neuron types. To this aim, we leveraged Hippocampome.org , an open‐access knowledge base of morphologically, electrophysiologically, and molecularly characterized neuron types in the rodent hippocampal formation. Specifically, we have implemented a computational pipeline to systematically translate neuron type properties into formal queries in order to find all compatible potential connections. With this system, we have collected nearly 40,000 synaptic data entities covering 88% of the 3,120 potential connections in Hippocampome.org . Correcting membrane potentials with respect to liquid junction potentials significantly reduced the difference between theoretical and experimental reversal potentials, thereby enabling the accurate conversion of all synaptic amplitudes to conductance. This data set allows for large‐scale hypothesis testing of the general rules governing synaptic signals. To illustrate these applications, we confirmed several expected correlations between synaptic measurements and their covariates while suggesting previously unreported ones. We release all data open‐source at Hippocampome.org in order to further research across disciplines.