脱细胞血管基质制备及体内外生物相容性

背景：利用脱细胞血管基质作为血管支架具有以下优点：脱细胞血管基质保留了自然血管的复杂三维结构;脱细胞基质表面的生长因子和结构域有利于细胞的黏附和浸润。 目的：制备脱细胞血管基质并对其体内外生物相容性进行评价。 方法：采用胰蛋白酶、Triton X-100逐步处理猪颈动脉制备脱细胞血管基质。采用皮下植入实验、急性毒性实验和体外细胞毒性实验等评价其生物相容性。 结果与结论：脱细胞基质材料具有良好的化学稳定性,未释放对红细胞产生破坏溶解作用的有害元素,未引起急性溶血反应,对细胞的生长无毒性影响。脱细胞基质材料在动物体内植入后早期有较多炎性细胞浸润,到实验观察的后期无明显炎性细胞浸润,脱细胞基质内可见成纤维细胞。另外,脱细胞基质材料对周边组织未产生毒性作用,伤口Ⅰ期愈合。同时组织学切片显示：支架材料与周边组织相容性好,未产生排斥反应。说明脱细胞基质材料在动物体内具有很好的生物相容性。 关键词：血管支架;生物相容性;生物材料;脱细胞血管基质;相容性 doi:10.3969/j.issn.1673-8225.2010.16.010     

内皮祖细胞复合血管无细胞基质替代输尿管的可行性☆

背景：临床治疗输尿管缺损,缺乏有效的输尿管替代物,而无细胞基质在体内单独作为支架,常引起替代段输尿管狭窄,但内皮祖细胞移植能改善缺血组织,参与血管新生。 目的：初步探讨内皮祖细胞复合的血管无细胞基质替代输尿管的可行性。 方法：将自体猪来源的内皮祖细胞以及平滑肌细胞一起种植在同种异体的颈动脉来源的血管无细胞基质中,体外孵育后进行猪长段输尿管的替代。 结果与结论：移植后4周,无细胞基质替代物已经开始与输尿管融合,替代物内可以明显见到上皮细胞层,肌细胞层以及新生的血管。但在移除输尿管支架管后,也就是在移植后12周的替代物标本中,发现移植物的萎缩和管腔的明显狭窄,移植物周围出现严重的纤维化炎症反应。替代段上方输尿管明显扩张积水,同侧肾脏明显萎缩,而且已经失去功能。 关键词：内皮祖细胞;血管;无细胞基质;输尿管;替代;泌尿系统组织构建;组织工程     

灌注法制备大鼠全肾脏脱细胞基质支架的细胞相容性☆

背景：作者所查目前尚未见应用灌注法制备大鼠全肾脱细胞基质的相关报道，制备的脱细胞基质是否具有良好的细胞相容性尚不确切。 目的：应用灌注法制备大鼠全肾脏脱细胞基质支架，检测鼠肾脱细胞基质与L929细胞的细胞相容性，探讨灌注法制备的肾脱细胞基质作为细胞支架构建泌尿系实质性组织工程器官的可行性。 设计、时间及地点：体外细胞水平观察实验，于2009-02/05在南方医科大学珠江医院中心实验室完成。 材料：取12周龄Wistar大鼠的肾脏，保留输尿管、肾静脉及肾动脉，沿肾动脉插入留置针建立灌注通道。灌注压强为9.81 kPa，依次灌注肝素化PBS溶液，1%十二烷基磺酸钠溶液，去离子水，1% TritonX-100溶液以及含青链霉素的PBS溶液，制备全肾脱细胞基质支架。 方法：①设立空白组(无细胞)、阴性对照组(培养基)和实验组(鼠肾脱细胞基质浸提液)及阳性对照组(含0.64%苯酚溶液的培养基)。取对数生长期的L929细胞，4×103/孔接种于96孔板中，每组各5孔，于接种24，72，120 h，通过MTT法显色，于酶标仪490 nm波长下检测吸光度值，计算相对增殖率。②设立对照组(培养基)、实验组(鼠肾脱细胞基质浸提液)及阳性对照组(含0.64%苯酚溶液的培养基)，培养48 h后应用流式细胞技术检测细胞凋亡情况。 主要观察指标：①支架微观结构。②细胞毒性。③细胞凋亡率。 结果：脱细胞基质支架扫描电镜观察仅见基膜及胶原蛋白等细胞外基质形成网状结构而无细胞残留，24，72，120 h实验组吸光度值与阴性对照组比较差异无显著性意义(P > 0.05)。脱细胞基质细胞毒性为0级和1级。实验组与阴性对照组之间细胞凋亡率差异无显著性意义(P > 0.05)。 结论：大鼠全肾脏脱细胞基质支架具有良好的细胞相容性。 关键词：肾脏；脱细胞基质；细胞毒性；凋亡；组织工程     

羊膜脱细胞基质的制备及其生物相容性

目的：羊膜是一种天然的细胞外基质，具有抗原性低、排异反应小特点。实验拟进行羊膜脱细胞基质的制备，观察其作为组织工程支架材料的生物相容性。 方法：实验于2007-03/08在河北医科大学解剖教研室实验中心完成。实验材料：4～6周龄健康清洁级SD大鼠,体质量100～ 150 g，由河北医科大学实验动物中心提供。实验过程中对动物处置符合动物伦理学标准。新鲜人羊膜取自石家庄市第四医院，采取前征得产妇知情同意，实验经医院伦理委员会批准。实验方法：①取新鲜人羊膜冲洗后以1%tritonX-100溶液振荡24 h，0.25%胰蛋白酶37 ℃振荡4 h，充分漂洗，冷冻干燥，环氧乙烷消毒，并进行苏木精-伊红染色和扫描电镜检测。②体外分离培养SD大鼠骨髓间充质干细胞，并复合培养于羊膜脱细胞基质上，以不含细胞的培养基作为空白对照，以普通培养基培养作为阴性对照，倒置显微镜下观察生长情况，并进行苏木精-伊红检测。四甲基偶氮唑盐法测定羊膜脱细胞基质浸提掖对骨髓间充质干细胞毒性；将羊膜脱细胞基质植入SD大鼠背部皮下，检测其组织相容性。 结果：①制备的羊膜脱细胞基质为白色菲薄、半透明的膜状物，柔韧性好，经苏木精-伊红和扫描电镜检测无细胞残留。苏木精-伊红染色可见羊膜表面细胞黏附生长良好，细胞伸展，形态与正常培养细胞无差异。②实验组第2、4、6、8天的吸光度值低于对照组，相对增殖率随培养时间延长而增加，平均相对增殖率为89.5%，细胞毒性评分均为1级。③皮下埋置术后动物全部成活，伤口无红肿、渗液等炎症反应，移植物均未见坏死、纤维化等。光镜下，术后1周移植物周围可见以淋巴细胞为主的炎症细胞浸润，羊膜卷尚完整；术后2周，淋巴细胞减少，偶见新生毛细血管；术后4周，部分移植物已经降解，基本未见淋巴细胞。 结论：经去污剂和酶消化法制备的羊膜脱细胞基质生物相容性良好，是一种理想的组织工程支架材料。     

未经预处理同种活性生物脱细胞支架的免疫原性及支架张力★

背景：提高生物材料组织相容性的主要办法目前主要采用预处理，但是诸多预处理方法都有缺点，如经预处理后生物组织材料常发生钙化、细胞毒性反应、抗张力强度降低等。 目的：观察未经预处理的生物支架材料的免疫原性、支架张力、细胞生长因子对支架的影响，以及此条件下制备同种活性生物脱细胞支架的方法。 设计：组织形态学层面的对比观察实验。 时间及地点：实验于2006-06/2007-03在南通大学附属医院普通外科完成。 材料：SPF级成年Wistar大鼠。十二烷基硫酸钠为美国BiotechGrade产品；碱性成纤维细胞生长因子,血管内皮生长因子为英国Peprotech Company产品；测力计为苏州电器元件一厂产品。 方法：选取新鲜大鼠下腔静脉作为实验材料，用含十二烷基硫酸钠的Tris低渗缓冲液，以改进的Booth法脱去静脉壁的上皮细胞，固定剂固定后，分别行HE染色、胶原纤维染色的光镜和扫描电镜观察、摄片，并用测力计测量支架在脱细胞前后张力的改变。将支架材料进行同种异体间动物皮下埋置，观察脱细胞支架埋置局部有无红肿等免疫排斥反应。把脱细胞支架结合血管内皮生长因子和/或碱性成纤维细胞生长因子移植于同种大鼠皮下，2周后采用免疫组化法观察支架内血管的长入情况，使用测力计测量支架在埋置前后张力的改变。 主要观察指标：支架经脱细胞处理和移植入大鼠皮下前后张力的改变。支架内新生血管长入情况。皮下植入的支架局部排斥反应。 结果：用质量浓度为0.03％十二烷基硫酸钠的Tris低渗缓冲液与静脉壁共同孵育48 h后，HE染色、胶原纤维染色的光镜和扫描电镜显示：静脉壁完全脱去了表面的上皮细胞，又较完整地保留了胶原纤维等细胞外基质主要成分：其形态学结构及支架张力在脱细胞前后差异无显著性意义（P > 0.05）。在支架植入部位无明显免疫排斥反应，局部切口愈合良好。支架植入2周后，血管内皮生长因子和碱性成纤维细胞生长因子能在短期内促进新的血管长入支架内，碱性成纤维细胞生长因子+血管内皮生长因子联合应用后新生血管长入最显著。移植前后支架的张力差异无显著性意义（P > 0.05）。 结论：未经预处理，用含质量浓度为0.03％十二烷基硫酸钠的低渗Tris缓冲液对制备的脱细胞支架在同种异体动物皮下埋置无排斥反应，支架强度无明显变化。碱性成纤维细胞生长因子、血管内皮生长因子可促进新生血管在支架内的生长，并具有协同作用。     

不同浓度细胞种植脱细胞血管基质上构建组织工程血管

摘要 背景：前期研究表明制备的脱细胞血管基质适合平滑肌细胞和内皮祖细胞生长,但是共培养模型中细胞接种密度对血管基质上细胞覆盖率的影响尚不清楚。 目的：观察不同浓度度细胞种植在脱细胞血管基质上的生长情况。 方法：采用两步法进行细胞种植,先将不同细胞浓度血管平滑肌细胞种植在脱细胞血管基质上,培养3 d后再将不同浓度内皮祖细胞接种在平滑肌细胞-血管基质复合体上,构建片状组织工程材料,分别在内皮祖细胞种植后3 d、1周时间段获取标本,扫描电镜观察细胞在材料上的生长情况。 结果与结论：血管平滑肌细胞和内皮祖细胞在脱细胞基质表面生长良好。不同浓度细胞在基质上的排布不同;提高接种的浓度有利于在材料表面快速形成致密的细胞层。提示采用两步法以合适的浓度种植细胞于脱细胞基质上,可以构建组织工程血管。 关键词：内皮祖细胞;平滑肌细胞;组织工程血管;脱细胞血管基质;种植 doi:10.3969/j.issn.1673-8225.2010.47.010     

以肝素固化脱细胞支架构建的小口径抗凝人工血管

背景：目前临床上直径< 6 mm的小口径人工血管因生物相容性差、远期通畅率低，使用效果并不理想。 目的：通过对脱细胞血管支架表面固化肝素，制备一种具有抗凝血功能的小口径生物人工血管。 设计、时间及地点：细胞学、组织病理学体外观察，于2005-12/2007-12在鼓楼医院实验室完成。 材料：普通成年杂种犬8只，雌雄不限，体质量约20 kg。 方法：采用去污剂-酶消化法制备犬颈动脉脱细胞支架，并将肝素分子交联至支架表面。将制备的肝素固化血管和脱细胞血管基质植入犬颈动脉进行异体血管移植实验。 主要观察指标：通过血小板黏附实验和细胞接触实验评价其血液、生物相容性能；经异体血管移植实验观察其早期血栓形成情况。 结果：脱细胞支架细胞成分去除完全，而胞外基质保留完整；经肝素固化后具有良好的抗凝血性能，细胞接触实验未显示细胞毒性；植入异体犬颈动脉1个月后，发现肝素固化组移植血管均维持通畅，而植入单纯脱细胞血管基质者因血栓形成而闭塞。 结论：对同种异体脱细胞血管支架进行表面肝素固化，可获得一种具有良好生物相容性和血液相容性的小口径人工血管。     

组织工程心脏瓣膜不同脱细胞方法的比较

背景：目前对几种脱细胞方法的效果各家观点不同。大都认为各种方法均可去除细胞，但实验结果却有较大差异。 目的：对比胰蛋白酶法、十二烷基硫酸钠法和去氧胆酸钠法去除细胞后心脏瓣膜形态学及生物力学特征。 设计、时间及地点：对比观察实验，于2007-10/2008-07在上海交通大学医学院细胞生物学实验室和上海交通大学医学院附属新华医院进行。 材料：40个新鲜猪主动脉瓣120片瓣叶分为3组，分别为胰蛋白酶组、十二烷基硫酸钠组和去氧胆酸钠组，每组40片。 方法：胰蛋白酶消化法：置于0.5 g/L胰蛋白酶和0.2 g/L乙二胺四乙酸， 在37 ℃，体积分数为0.05 CO2培养箱中振荡24 h。十二烷基硫酸钠法：置于0.3 g/L十二烷基硫酸钠和DNase，RNase中持续振荡24 h。去氧胆酸钠法：首先在5 g/L Triton-X 100，5 g/L去氧胆酸钠，0.2 g/L 乙二胺四乙酸中振荡24 h，然后在2.5 g/L Triton-X 100，2.5 g/L去氧胆酸钠和0.2 g/L 乙二胺四乙酸中破膜去污振荡48 h，两阶段均加入DNase，RNase。 主要观察指标：3种方法去细胞前后心脏瓣膜的生物力学特性变化。3种方法去除细胞程度和对胶原纤维、弹力纤维的影响。 结果：去氧胆酸钠组拉伸率、最大拉伸应力、最大载荷均高于十二烷基硫酸钠组和胰蛋白酶组（P < 0.01）。胰蛋白酶法脱细胞效果差，对基质破坏明显；十二烷基硫酸钠法可完全脱细胞，对基质破坏较大；去氧胆酸钠法完全脱细胞同时对基质破坏较少。 结论：与胰蛋白酶法、十二烷基硫酸钠法比较，去氧胆酸钠法脱细胞效果好，能更好保护基质。     

无细胞基质组织工程膀胱生物支架材料的生物力学特征

背景：前期研究表明，无细胞基质的组织工程膀胱支架材料有良好的生物相容性，无毒可吸收，符合组织工程生物支架材料的部分应用要求。 目的: 实验拟进一步观察无细胞基质组织工程膀胱生物支架材料的生物力学特性。 设计、时间及地点：对比观察实验，于2006-07/2007-05在中国医学科学院北京协和医院中心实验室和北京大学高分子科学与工程系完成。 材料：新鲜猪膀胱。 方法:采用低渗-去污剂洗涤-核酸酶消化法对新鲜猪膀胱组织进行脱细胞处理，制备无细胞基质膀胱。对新鲜猪膀胱组织及制备的膀胱无细胞基质行苏木精-伊红染色和Masson染色。 主要观察指标：测定膀胱组织在脱细胞前后组织的厚度、组织含水量、可溶性蛋白含量、最大位移、最大应力和断裂应力。 结果: 与新鲜膀胱组织相比，脱细胞后的膀胱组织中未见有细胞成分，保留了完整的细胞外基质。膀胱组织含水量在脱细胞后明显增加（P < 0.001），组织厚度和可溶性蛋白含量明显降低，而经校正后的应力－应变参数及破坏强度则改变不明显。 结论:无细胞基质膀胱与天然组织的生物力学特性一致或接近。     

骨髓间充质干细胞在膀胱脱细胞基质上的生长及分化***★

背景：传统方法多采用平滑肌细胞和移行上皮细胞构建组织工程膀胱，并进行支架材料的双面种植，但由于平滑肌细胞取材培养困难，且体外传代有限，双面种植较为困难。 目的：实验拟验证以骨髓间充质干细胞及膀胱脱细胞基质构建组织工程膀胱的可行性。 设计：基础实验研究。 单位：中山大学附属第二医院林百欣医学研究中心。 材料：实验于2006-03/2007-05在中山大学附属第二医院林百欣医学研究中心完成。实验室级别为卫生部部属医院开放实验室。1月龄SD大鼠，雌雄不限，体质量80~ 100g，由中山大学实验动物中心提供。新鲜猪膀胱取自南方医科大学动物实验中心。 方法：采用全骨髓培养连续贴壁法体外培养大鼠骨髓间充质干细胞，并应用流式细胞仪检测其表面抗原。采用去污剂洗涤法制备猪膀胱脱细胞基质，并测定其纯度及特性。将第3代骨髓间充质干细胞接种到膀胱脱细胞基质上，以添加25 ng/L血管内皮生长因子（VEGF165）的培养液进行体外、体内复合培养，检测其相容性。体内实验以细胞单独培养为对照，体外实验以未植入细胞的材料为对照，并模拟合适的微环境诱导骨髓间充质干细胞生长分化，分别在4，8周后取出动物体内的复合材料行组织切片检查，并进行免疫组织化学角蛋白染色，检测上皮细胞再生情况。 主要观察指标：骨髓间充质干细胞与膀胱脱细胞基质的生物相容性。 结果：①采用全骨髓法成功培养出骨髓间充质干细胞，行流式细胞仪检测细胞表面抗原显示，传代第3代细胞CD29阳性细胞为99.43%。②制备的膀胱脱细胞基质具有良好的生物特性，镜下见均质状态的基质和细丝状的胶原纤维。体内外相容性实验表明骨髓间充质干细胞与膀胱脱细胞基质具有良好的相容性，细胞生长状态良好。③4周后组织切片检查可见组织中较多炎症细胞浸润，胶原及弹性纤维排列紧密，免疫组织化学角蛋白染色见有薄层、不连续的单层上皮生长，8周后可见组织中已无明显炎症细胞浸润反应，胶原及弹性纤维排列紧密，免疫组织化学角蛋白染色见有薄层、连续的多层上皮生长。 结论：骨髓间充质干细胞与膀胱脱细胞基质具有良好的生物相容性，并且在体内与周围组织有良好的生物相容性，可以作为构建组织工程膀胱的材料。     

Hepatic Considerations in the Use of Antiepileptic Drugs

Summary: Virtually all of the major antiepileptic drugs (AEDs) can cause hepatotoxicity, although fatal hepatic reactions are rare. The mechanisms, incidences, and risk profiles for such reactions differ from drug to drug. With carbamazepine and phenytoin, hepatotoxicity may be due to drug hypersensitivity. Although the profiles of patients at risk have not been well-defined for these two antiepileptic drugs, it would appear from reports in the literature that older adolescents and adults are at higher risk than children of developing serious or fatal hepatotoxicity. Once hepatotoxicity develops, mortality rates are 10–38% with phenytoin and 25% for carbamazepine. The risk profile for valproate fatal hepatotoxicity has been more clearly defined. Those at primary risk of fatal hepatic dysfunction are children under the age of 2 years who are receiving multiple anticonvulsants and also have significant medical problems in addition to severe epilepsy. The risk is considerably lower for patients over the age of 2 years on valproate monotherapy. In contrast to the risk profile with other AEDs, adults receiving valproate as monotherapy have the lowest risk of hepatotoxicity. Fatal hepatic dysfunction coincident with valproate may be the result of aberrant drug metabolism. Concomitant use of AEDs that induce microsomal P450 enzymes (e.g., phenytoin and phenobarbital) may enhance the production of a toxic metabolite, and hence the greater risk of hepatotoxicity with polypharmacy.     

Vascular Malformations and Epilepsy: Clinical Considerations and Basic Mechanisms

Summary: Vascular malformations (VMs) are associated with epilepsy. The natural history of the various VMs, clinical presentation, and tendency to provoke epilepsy determine treatment strategies. Investigations have probed the mechanisms of epileptogenesis associated with these lesions. Electrophysiologic changes are associated with epileptogenic cortex adjacent to VMs. Putative pathophysiologic mechanisms of epileptogenesis include neuronal cell loss, glial proliferation and abnormal glial physiology, altered neurotransmitter levels, free radical formation, and aberrant second messenger physiology.     

Diagnostic Difficulties and Treatment Implications

Summary: Differentiation between types of epileptic seizures has been aided in recent years by the introduction of intensive neurodiagnostic techniques and the development of increasingly detailed classification systems. Paradoxically, these developments have not simplified the task of matching the appropriate antiepileptic drug to a particular seizure type. It is reasonable to assume that anticonvulsant drugs will have different effects on different types of seizures, but faulty, circular reasoning can enter the picture if one also assumes that responses of seizures to different drugs signify different seizure types. There are several examples of differential diagnoses that can fall prey to this problem, including the diagnosis between partial seizures with secondary generalization and generalized tonic-clonic seizures, and the diagnosis between complex partial seizures and absence seizures with automatisms, among others. Considerations of etiology in future classification systems can further complicate the problem: should one then choose an anticonvulsant drug on the basis of individual seizure type or on the basis of the type of epilepsy? Ramifications of this issue extend even to the drug approval process. Official sanction is not given for use of a drug for a seizure type not included in the original efficacy studies, even if later scientific evidence shows that seizure type to be related to a type that is included. New trials must be undertaken. These problems arise from how we choose to classify seizures.     

Cognitive Dysfunction Associated with Antiepileptic Drug Therapy

Summary: Epilepsy is frequently associated with cognitive dysfunction. However, the reasons for this correlation are unclear. Possible influential factors include patient age; duration, frequency, etiology, and type of seizures; hereditary factors; psychosocial issues; and antiepileptic drug (AED) therapy. Whereas many of these factors are beyond the physician's control, AED therapy is one element that can be addressed in treatment decisions by recognizing the potential cognitive effects of particular AEDs. For example, phenobarbital impairs memory and concentration; phenytoin affects attention, problem solving ability, and performance of visuomotor tasks. In contrast, carbamazepine may affect concentration, while valproate would appear to have minimal effects on cognition. Moreover, cognitive effects of AEDs are amplified with coadministration of multiple anticonvulsants (polytherapy). A review of studies on the cognitive effects of monotherapy with AEDs, as opposed to those of polytherapy, provides evidence that drug-related cognitive dysfunction can be reversed if patients are switched to a simpler therapeutic regimen. Future research should be directed toward developing reliable measures for assessing and monitoring cognition, and understanding the particular cognitive side effects of each AED. Physicians also need to revise their opinions about which side effects are "tolerable" for epileptic patients.     

Epilepsy and anomalies of neuronal migration: MRI and clinical aspects

Neuronal migration disorders are the result of disturbed brain development. In such disorders, neurons are abnormally located. In diagnosing these conditions, magnetic resonance imaging is superior to any other imaging technique. This enables us to improve our knowledge of the clinical correlates of neuronal migration. With reference to migrational disorder, a retrospective study of all 303 patients with epileptic seizures referred for magnetic resonance imaging during a 3-year period was performed, 13 patients (aged 12-41, mean age 27) were identified. They represent 4.3% of the entire study group. Of the patients with known epilepsy, 6.7% and of the mentally retarded, 13.7% had migrational disorders. Four patients had schizencephaly as the dominant finding, one was classified as hemimegalencephaly, 2 had isolated heterotopias, and 6 had localized pachy- and/or poly-microgyria. The clinical pictures are complex. Ectopias of grey matter are recognised foci of epilepsy, but from an epileptological and a clinical viewpoint little attention has been given to these disorders. The present study shows that malmigration is not rare in epilepsy patients, especially not in the mentally retarded.     

Carbamazepine Efficacy and Utilization in Children

Summary: Carbamazepine is effective for preventing partial and generalized tonic-clonic seizures in children. Although absence epilepsies are more common in children than adults, an estimated 80% of children with epilepsy have seizure types or epilepsies that are potentially responsive to carbamazepine. The differential diagnosis of ictal staring is an especially important issue in children because absence and atypical absence seizures are more prevalent in children than adults. Age-related pharmacokinetic differences and drug interactions are major considerations in children. On average, children have higher clearance rates of carbamazepine, shorter half-lives, and higher ratios of carbamazepine-10, 11-epoxide to carbamazepine than adults. In addition, children with severe epilepsy are more likely to require multiple-drug therapy, which can lead to complex drug interactions. When carbamazepine is administered along with valproate, drug protein binding interactions can cause intermittent side effects.     

Carbamazepine Efficacy in Adults With Partial and Generalized Tonic-Clonic Seizures

Summary: Carbamazepine and phenytoin are drugs of choice in initial monotherapy for adult partial and secondarily generalized tonic-clonic seizures. These designations reflect the results of the Veterans Administration Epilepsy Cooperative Study Group of 1985. An earlier comparative study of carbamazepine and phenytoin by Ramsay and associates found both drugs equally effective in controlling new-onset seizures. Among the advantages of carbamazepine is that it causes relatively few cognitive and dysmorphic side effects. Its disadvantages are its unavailability in parenteral formulation and its metabolic autoinduction. The latter must be compensated for by planned dosage increases to maintain therapeutic plasma steady-state levels during the first 2 or 3 months of treatment. Carbamazepine is judged a drug of choice in the treatment of these secondarily generalized tonic-clonic seizures, and the drug of choice in children, adolescents, and women susceptible to the dysmorphic side effects associated with other anticonvulsant agents.     

Etiologic and Preventive Aspects of Epilepsy in the Child–Bridging the Gap Between Laboratory and Clinic

Summary: Four broad categories of basic phenomena are pertinent to developing ways to prevent epilepsy. These include mechanisms of epileptogenesis, ictal initiation and temporary entrainment by the seizure discharge of normally functioning brain, seizure propagation, and control mechanisms that function both to restrain the cascade of epileptic events culminating in a seizure and to arrest the epileptic event and restore the interictal state. In newborns and children, hypoxia-ischemia is a major factor leading to epileptogenesis, and several schemes are proposed to classify, quantify, and prevent hypoxic-ischemic encephalopathy. Control mechanisms must be better understood in order to develop prophylactic recommendations for epilepsy, and an experimental model of "kindling antagonism" may increase our understanding of these. Programs of prevention of seizures in children will evolve only if basic researchers and clinicians work productively together to develop an adequate understanding of factors important in epileptogenesis and antiepileptogenic control mechanisms.     

Predisposing and Causative Factors in Childhood Epilepsy

Summary: We review information from large studies of defined populations, examining the role of known factors and especially of prenatal and perinatal factors in contributing to nonfebrile seizure disorders of early childhood. We depend especially, but not exclusively, on the recently completed analyses from the Collaborative Perinatal Project of the National Institute of Neurological and Communicative Disorders and Stroke, the NCPP. About 4% of children in the NCPP who had at least one non-febrile nonsymptomatic seizure by the age of 7 years had a previous seizure during acute neurologic illness, such as meningitis or during the acute illness after trauma. Many such seizures should potentially be preventable. Of children with seizures, 10% had had a neonatal seizure and 13% had had a febrile seizure. Among the hundreds of prenatal and perinatal factors explored as predictors of childhood seizure disorders, the principal predictors identified were congenital malformations of the fetus, cerebral and noncerebral; family history of certain neurologic disorders; and neonatal seizures. In agreement with the British National Child Development Study, labor and delivery factors in the NCPP appeared to contribute very little to childhood seizure disorders. Maldevelopment, rather than damage at birth to an initially intact nervous system, appeared to be the more common mechanism. Most seizure disorders of early childhood remained unexplained by the large set of prenatal and perinatal characteristics examined.     

Classification of methods in transcranial Electrical Stimulation (tES) and evolving strategy from historical approaches to contemporary innovations

Transcranial Electrical Stimulation (tES) encompasses all methods of non-invasive current application to the brain used in research and clinical practice. We present the first comprehensive and technical review, explaining the evolution of tES in both terminology and dosage over the past 100 years of research to present day. Current transcranial Pulsed Current Stimulation (tPCS) approaches such as Cranial Electrotherapy Stimulation (CES) descended from Electrosleep (ES) through Cranial Electro-stimulation Therapy (CET), Transcerebral Electrotherapy (TCET), and NeuroElectric Therapy (NET) while others like Transcutaneous Cranial Electrical Stimulation (TCES) descended from Electroanesthesia (EA) through Limoge, and Interferential Stimulation. Prior to a contemporary resurgence in interest, variations of transcranial Direct Current Stimulation were explored intermittently, including Polarizing current, Galvanic Vestibular Stimulation (GVS), and Transcranial Micropolarization. The development of these approaches alongside Electroconvulsive Therapy (ECT) and pharmacological developments are considered. Both the roots and unique features of contemporary approaches such as transcranial Alternating Current Stimulation (tACS) and transcranial Random Noise Stimulation (tRNS) are discussed. Trends and incremental developments in electrode montage and waveform spanning decades are presented leading to the present day. Commercial devices, seminal conferences, and regulatory decisions are noted. We conclude with six rules on how increasing medical and technological sophistication may now be leveraged for broader success and adoption of tES.