Development of specificity in corticospinal connections by axon collaterals branching selectively into appropriate spinal targets

Corticospinal projections in adult rodents arise exlusively from layer V neurons in the sensorimotor cortex. These neurons are topographically organized in their connections to spinal cord targets. Previous studies in rodents have shown that the mature distribution pattern of corticospinal neurons develops during the first 2 weeks postnatal from an initial widespread pattern that includes the visual cortex to a distribution restricted to the sensorimotor cortex. To determine whether specificity in corticospinal connections also emerges from an intially diffuse set of projections, we have studied the outgrowth of corticospinal axons and the formation of terminal arbors in developing hamsters. The sensitive fluorescent tracer 1, 1′, dioctadecyl-3, 3, 3′, 3′-tetramethylindocarbocyanine perchlorat (DiI) was used to label corticospinal axons from the visual cortex or from small regions of the forelimb or hindlimb sensorimotor cortex in living animals at 4–17 days postnatal. Initially axon outgrowth was imprecise. Some visual cortical axons extended transiently beyond their permanent targets in the pontine nuclei, by growing through the pyramidal decussation and in some cases extending as far caudally as the lumbar enlargement. Forelimb sensorimotor axons also extended past their targets in the cervical enlargement, in many cases growing in the corticospinal tract to lumbar levels of the cord. By about 17 days postnatal these misdirected axons or axon segments were withdrawn from the tract. Despite these errors in axon trajectories within the corticospinal tract, terminal arbors branching into targets in the spinal gray matter were topographically appropriate from the earliest stages of innervation. Thus visula cortical axons never formed connections in the spinal cord, forelimb sensorimotor axons arborized only in the cervical enlargement, and hindlimb cortical axons terminated only in the lumbar cord at all stages of development examined. Corticospinal arbors formed from collaterals that extended at right angles from the shafts of primary axons, most likely by the process of interstitial branching after the primary growth cone had extended past the target. Once collaterals extended into the spinal gray matter, highly branched terminal arbors formed within 2–4 days, beginning at about 4 and 8 days postnatal for the cervical and lumbar enlargements, respectively. These results show that specificity in connectivity is achieved by selectivty growth of axon collaterals in to appropriate spinal targets from the beginning and not by the later remodeling of intially diffuse connections. In contrast, errors occur in the initial outgrowth of axons in the corticospinal tract, which are subsequently corrected. Copyright © 1994 Wiley-Liss, Inc.     

精子尾部低渗肿胀试验、DNA荧光染色有效精子计数在精液分析中的意义

本文对１６０名有正常生育力的男性精液标本同时进行了精子尾部低渗肿胀率（ＨＯＳ）、精子头部ＤＮＡ荧光染色的有效精子计数（ＥＳＣ）、前向运动精子百分率（ＰＭＳ）、活动精子百分率（ＭＳ）的检测，分析它们之间的一致性。结果发现：ＨＯＳ与ＰＭＳ或ＭＳ间的符合率分别为７４％与８８％；ＥＳＣ与ＰＭＳ或ＭＳ间的符合率分别为６３％与６６％；ＥＳＣ与ＨＯＳ间的符合率为６７％。提示ＨＯＳ或ＥＳＣ可从不同角度去反映被测精子的生育力。     

Effects of dauricine,quinidine,and sotalol on action potential duration of papillary muscles in vitro

目的：观察蝙蝠葛碱对豚鼠乳头状肌的动作电位是否具有使用依赖性特征，并与奎尼丁、索他洛尔作平行比较．方法：利用细胞内微电极技术记录豚鼠乳头状肌跨膜动作电位．结果：蝙蝠葛碱２０μｍｏｌ·Ｌ－１能明显延长乳头状肌跨膜动作电位时程，在刺激周长为２００，３００，４００，６００，８００，１０００，２０００ｍｓ时，其延长动作电位时程的百分率分别为２２±８，１１±６，９±５，７±５，６±３，４３±２８，４５±２８，蝙蝠葛碱延长动作电位时程作用于刺激周期较短时作用明显，呈使用依赖性特征．而奎尼丁１μｍｏｌ·Ｌ－１和索他洛尔１０μｍｏｌ·Ｌ－１延长动作电位时程作用随刺激周期延长而增强，呈现逆向使用依赖性特征．结论：蝙蝠葛碱使用依赖性延长豚鼠乳头状肌动作电位时程．     

尿胰蛋白酶原-2及Uamy/Ucr比值在急性胰腺炎诊断中的意义

目的 探讨尿淀粉酶/尿肌酐（Uamy/Ucr）比值及尿胰蛋白酶原-2（urine trypsinogen-2）的测定对急性胰腺炎的临床诊断价值.方法 对70例急性胰腺炎患者、50例非急性胰腺炎急腹症患者和50例健康对照人员进行血清淀粉酶（Samy）、尿淀粉酶（Uamy）、Uamy/Ucr及尿胰蛋白酶原-2测定.结果 尿胰蛋白酶原-2和Uamy/Ucr比值进行联合诊断的敏感性、特异性最高,分别为97.14%和98.00%;尿胰蛋白酶原-2检测的敏感性为94.28%,特异性为96.00%;Uamy/Ucr比值的敏感性为92.86%,特异性为92.00%;Samy的敏感性为85.71%,特异性为84.00%;Uamy的敏感性为81.42%,特异性为80.00%.结论 Uamy/Ucr比值及尿胰蛋白酶原-2是较好的早期诊断急性胰腺炎的指标.     

对硫磷人工抗原合成及其鉴定

目的 制备对硫磷人工抗原和抗血清，为建立酶联免疫吸附法提供技术储备。方法 还原对硫磷硝基成为氨基，合成半抗原氨基对硫磷；重氮化偶联大分子载体牛血清白蛋白制备人工抗原；免疫新西兰白兔。进行多抗制备。结果 合成的半抗原核磁共振图谱鉴定结果为6：6．9～7(m，2H，CH2)6．4～6．5(m，2H，CH2)4．1～4．2(q，4H-CH2)3．4(s，2H，NH2)1．3～1．4(t，6H，CH3)；氨基对硫磷与牛血清白蛋白的结合比为35～36：1；抗血清经间接酶联免疫吸附法检测，效价达1：128000，双向免疫扩散实验测得抗血清与人工抗原形成沉淀；间接竞争酶联免疫吸附法测得抗血清对对硫磷最低抑制浓度为0．16ng／mL；经间接酶联免疫吸附法检测人工抗原与羊抗人血清、兔抗人血清、正常兔血清无交叉反应。结论 合成对硫磷半抗原及人工抗原纯度高、结合比高。具有较好的免疫原性。     

脉冲式电磁辐射对大鼠血脑屏障影响的量效关系

目的 研究脉冲式电磁辐射(EMR)对大鼠血脑屏障(BBB)影响的量效关系。方法 采用伊思蓝静脉注射，荧光显微镜下观察不同脉冲次数的EMR辐照对大鼠BBB开放的影响。结果 伊思蓝在EMR诱发的大鼠BBB开放局部呈现荧光斑；随着EMR脉冲次数(0～200次)的增加，荧光斑数量增加、面积增大；荧光斑在EMR组全脑的分布，以皮质、丘脑、下丘脑、小脑、尾壳核和延髓较多。结论 不同脉冲次数EMR诱发大鼠BBB开放程度不同，随脉冲次数增加，血管通透性增强，200次时达开放高峰，皮质区BBB开放最明显。     

体外丹参、藻酸双酯钠对脑血栓形成患者红细胞与内皮细胞粘附的影响

丹参、藻酸双酯钠是临床治疗脑血管病的常用药。本研究发现，在体外流场中用丹参、藻酸双酯钠分别处理脑血栓形成病人的红细胞后，此红细胞与培养的人脉静脉内皮细胞的粘附数目明显减少、粘附强度明显减弱；而且，在临床常用剂量下藻酸双酯钠的这种抗粘附作用优于丹参。认为丹参、藻酸双酯钠的这种抗粘附作用可能是临床用以治疗脑血栓形成的一个重要机理。     

医院感染及漏报率统计分析

目的　了解我院医院感染发生及漏报率。方法　将我院 2 0 0 3年 1～ 12月出院的所有病例进行回顾性调查。结果　医院感染率 7.3 2 %、漏报率 14 .93 %,均符合国家卫生部要求。结论　做好医院感染监测工作 ,严格执行各项工作制度 ,掌握医院感染与手术并发症的鉴别诊断 ,提高医院感染诊断的准确率     

床边纤维支气管镜检查在可疑院内获得性肺炎诊断中的意义

目的评价床边纤维支气管镜检查在可疑院内获得性肺炎诊断中的意义。方法对25例可疑院内获得性肺炎患者进行床边纤维支气管镜检查，同时进行痰标本和支气管肺泡灌洗液标本涂片细菌检测和培养。结果1例为肺出血，2例肺不张，1例肺水肿；21例为院内获得性肺炎，其中14例(72．7％)细菌培养阳性，革兰阴性杆菌占57．1％(12／21)，以铜绿假单胞菌、不动杆菌属、嗜麦芽假单胞菌、肺炎克雷伯菌最常见，革兰阳性球菌2例(9．5％)，主要是耐甲氧西林金黄色葡萄球菌。痰涂片和支气管肺泡灌洗液涂片阳性者分别为3例和10例。支气管肺泡灌洗液细菌涂片阳性率和细菌培养阳性率均高于痰标本(P=0．02和P=0．005)。结论床边纤维支气管镜检查有助除外疑似院内获得性肺炎的非感染性疾病。支气管肺泡灌洗液标本病原学检测优于痰标本。     

全喉切除改良气管-咽吻合Ⅰ期发声重建术

目的：探讨全喉切除Ⅰ期发声重建术的改进术式。方法：采用低位气管切开，全喉切除，食管前壁黏膜重建声门，气管切口处造瘘．颈段气管上提并缩窄吻合于舌根的方法行全喉切除及Ⅰ期发声重建木35例。结果：33例(94．29％）术后获得了不同程度的发声功能．不能发声者仅2例(5．71％)。全部患者术后均可经口进食，未出现严重的影响生存质量的误咽。结论：与以往的发声重建术相比，本术式具有发声成功率高、发声质量良好、误咽率低等优点，且无须置人人工发声装置．值得推广。