Calcium, network activity, and the role of NMDA channels in synaptic plasticity in vitro.

Functionally effective neuronal circuits are constructed through a competitive process that requires patterned neuronal activity elicited by structured input from the environment. To explore the mechanisms of this activity-dependent synaptic restructuring, we have developed an in vitro preparation of mouse spinal cord neurons maintained in a 3-chambered cell-culture system. Sensory afferents that received chronic electrical stimulation for 3-5 d developed stronger synaptic connections than unstimulated afferents converging onto the same postsynaptic spinal cord neuron. Exposure to 100 microM DL-2-amino-5-phosphonovaleric acid (APV), an antagonist of the NMDA channel, during the stimulation period prevented the competitive advantage associated with electric stimulation. However, when APV was applied with a higher concentration of calcium (3 mM), activity-dependent synaptic plasticity was no longer inhibited by the NMDA receptor antagonist. This reversal of APV block of the plasticity was not impaired by reducing transmitter release with 3 mM magnesium (in addition to 3 mM calcium and APV). A suppressant effect of APV on spontaneous activity was observed, which was attributed to loss of the NMDA component of the EPSP. Activity-dependent plasticity was also blocked if spontaneous activity was suppressed with dilute tetrodotoxin (TTX; 5-10 nM), a dosage that reduces excitability of neurons but is insufficient to block sodium-dependent action potentials. These experiments bring into question how NMDA channel activation is involved in the processes of synaptic remodeling during development. The data suggest that postsynaptic activity is required for synaptic remodeling, but this activity need not involve NMDA receptor activation specifically for activity-evoked synaptic plasticity. Instead, the mechanism for plasticity appears to operate through calcium-dependent processes in general.     

膨润土对药用混悬液助悬性能的考察

本文报道了无机胶体膨润土(Bentonite)作为助悬剂在炉甘石洗剂中的应用,并与有机助悬剂及另一种无机胶体XVT—M进行比较,显示了其优异的助悬性能。     

胞嘧啶脱氨酶的原核表达和多克隆抗体的制备

目的：在原核系统中表达并纯化大肠杆菌胞嘧啶脱氨酶（cytosine deaminase,CD)，制备鼠抗大肠杆菌CD多克隆抗体，方法：亚克隆CD基因到原核表达载体pMAL-c2和pBV222中，并转化入大肠杆菌DH5α内，诱导表达并纯化MBP-CD和6his-CD融合蛋白，用纯化的MBP-CD融合蛋白免疫小鼠制备多克隆抗体。结果：通过重组质粒的酶切筛选出重组阳性克隆，成功地表达和纯化出MBP-CD和6his-CD融合蛋白，用纯化的MBP-CD成功制备了鼠抗CD多克隆抗体，并用6his-CD和GST-CD重组蛋白进行Western印迹分析，证实了抗体的正确性，结论：应用多克隆抗体可以检测体内外CD基因的表达，为临床前和临床上深入开展CD基因的生物治疗研究提供重要的实验材料。     

开发EXECL高级功能实现试卷分析过程全自动化

教育测量学是在本世纪发展起来的一门教育分支学科，应用教育测量学原理和数理统计方法对考试结果进行分析，是目前各类学校提高教学质量所采取的必要措施之一。由于试卷统计分析的工作量非常大，手工计算近乎不可能，以往常应用SPSS、SAS等专业统计分析软件计算，但是这类软件在应用时还存在着普及性差、价格昂贵、使用复杂、英文界面、数据格式通用性低等缺点，无法大规模应用，     

小剂量低LET辐射对人淋巴细胞SCE的影响

本文用磷酸盐Giemsa法观察了小剂量X射线照射对人离体外周血淋巴细胞SCE的影响。其结果照射组各剂量点均不明显地高于对照组,证实了SCE对电离辐射不敏感,说明染色体结构畸变和SCE的发生是彼此独立的两个不同事件。     

影像学检查在儿童过敏性紫癜的临床价值

目的探讨儿童过敏性紫癜的影像学特点及其临床价值。方法回顾性分析32例过敏性紫癜并发肠套叠患儿的临床及影像学资料。结果出现并发症之前过敏性紫癜的腹部X线主要表现为局限性小肠充气扩张，粘膜增粗，肠间隙增宽，可伴有液平；B超显示为不同程度的多发节段性肠壁水肿增厚，肠管狭窄等表现；出现并发症后，其X线表现加重，部分病例伴有肠穿孔；B超及X线监视下空气灌肠可以明确是否并发肠套叠，部分病例可通过空气灌肠达到复位治疗的目的。结论影像学检查的重要临床价值在于能与需要手术治疗的其他急腹症相鉴别，同时可以了解其是否并发常见的并发症，为临床确定治疗方案提供可靠的信息。     

Plasma proteins in a standardised skin mini-erosion (II): effects of extraction pressure

Background  

A standardised suction technique has been used to sample plasma proteins in dermal interstitial fluid (IF) serially for 5 to 6 days from a suction-induced skin mini-erosion. Increased protein concentrations ascribed to inflammation have been shown from day 1 onward. In this study, we assessed the effect of two different extraction pressures on IF sample composition.     

Prof. Ye Chuanhui''s Experience in Treating Nephritic Proteinuria

In the occurrence and development of glomerulonephritis, proteinuria is themain manifestation, which is easily recurrent but not easily got rid of in a short period of time. It may remain even after disappearance of the general symptoms. In some patients, there are no symptoms and signs at all in the initial stage, except proteinuria, the only distinct manifestation. Prof. Ye Chuanhui, from Chengdu University of Traditional Chinese Medicine, has accumulated rich experience for treating this disorder, which is introduced in the following.     

胸腰段脊柱脊髓损伤减压与固定相关问题探讨（附166例报告）

目的 对胸腰段脊柱脊髓，马尾神经损伤患者的外科治疗及几种内固定方法的疗效进行探讨。方法 对166例患者的治疗进行回顾分析。该组患者中椎体爆裂性骨折37例，椎体压缩骨折超二分之一109例，椎体骨折脱位14例，多节段或跳跃骨折6例，脊髓损伤按Frankel分级，A级59例，B级46例，C级42例，D级19例，治疗采用后路减压复位122例，前路减压复位，髂骨植骨融合44例。结果 术后123例获3-18个月随访，随访患者中随4例RF钉断裂，5例Harrington上钩脱落，6例棍断裂，其余患者内固定稳固，脊髓，马尾神经恢复，除35例仍为A级外，余脊髓神经功能恢复1-3个级别。结论 各种不同内固定可保持或增强脊柱的稳定，胸腰段脊柱脊髓损伤的外科治疗应根据骨折类型，脊髓及马尾神经损伤程度选择手术入路及内固定材料。     

TRH、EGF及地塞米松促进未成熟胎肺组织分化及表面活性物质合成的研究

目的 比较TRH、EGF与地塞米松对未成熟胎肺形态发育及表面活性物质水平的影响。方法 在兔妊娠第22－24d或第24－26d分别用TRH、EGF或地塞米松母体静脉注射治病，通过光镜、图像分析及电镜等技术观察胎肺的形态结构，并检测胎肺的磷脂水平。结果 光镜下，TRH、EGF与地塞米松治疗组第25d及27d胎肺肺泡腔、肺泡间隔发育均明显好于对照组；EGF、TRH与地塞米松治疗组第27d胎肺的肺泡腔与肺泡间隔的面积比无明显差异。但EGF和TRH治疗组第25d胎肺的肺泡腔与肺泡间隔之比明显小于地塞米松治疗组。电镜下，三个治疗组第27d胎肺内含有板层体的Ⅱ型上皮细胞数量明显多于对照组，但各治疗组及对照组第25d的胎肺Ⅱ型上皮细胞胞浆内几乎未见明显板层体，相反胞浆内糖原含量却非常丰富。此外，三个治疗组27d胎肺的磷脂水平均明显高于对照组。结论 EGF、TRH及地塞米松在兔妊娠第24－26d母体治疗均能促进胎肺的形态发育和表面活性物质的合成，三种治疗方法对胎肺的影响程序无明显不同；在妊娠第22－24d治疗，地塞米松对胎肺形态结构的促进作用较EGF和TRH更明显，但三者对Ⅱ型上皮细胞分化及表面活性物质的合成均无明显影响。