透明质酸钠复合重组人骨形态发生蛋白2注射剂对下颌骨量的扩增作用

背景：对牙槽骨骨量需要扩增的患者而言，固态的支架材料并不太适用。寻找具有流动性和黏附能力、不占体积的材料是目前研究热点。 目的：观察透明质酸钠(sodium hyaluronate，SH)复合重组人骨形态发生蛋白2(recombinant human bone morphogenetic protein，rhBMP-2)注射剂对兔下颌骨量的扩增作用。 方法：60只兔按随机区组设计分为4组：rhBMP-2-SH组、rhBMP-2组、SH组分别于双侧下颌骨膜下置入rhBMP-2-SH复合物0.2 mL、rhBMP-2 0.5 mg、SH 0.2 mL。空白对照组双侧均切开后不作处理即关闭伤口。术后第2，4，8周分批处死动物。处死前作99Tcm-MDP骨显像；处死后切取标本作苏木精-伊红染色观察、胶原I免疫组化、碱性磷酸酶活性、骨钙素含量检测。 结果与结论：①rhBMP-2-SH组99Tcm-MDP骨显像下颌骨感兴趣区计数比值于2，8周时高于其他各组(P < 0.05)，4周时明显高于其他各组(P < 0.01)。②组织学观察rhBMP-2-SH组于术后2周即有新生骨小梁生成，至8周钙化成板层骨块，并且4周时可见透明软骨细胞出现，胶原Ⅰ免疫组化只在2周骨基质中呈强阳性表达。③rhBMP-2-SH组碱性磷酸酶活性指数明显高于其他各组(P < 0.01)；并随着时间延长而逐渐增高(P < 0.01)。④rhBMP-2-SH组骨钙素含量于4周及8周时明显高于其他各组(P < 0.01)，并随着时间延长而逐渐增高(P < 0.01)。提示rhBMP-2-SH注射剂能于兔下颌骨表面稳定地形成新骨从而达到骨量扩增效应。成骨方式为混合型成骨方式，以膜内成骨为主。 关键词：骨形态发生蛋白；透明质酸钠；注射型；载体；骨量扩增 doi:10.3969/j.issn.1673-8225.2010.12.005     

自体骨膜包裹肌腱复合松质骨匀浆及重组人骨形态发生蛋白2体内成骨重建月骨*★

背景：月骨摘除术后选择合适的月骨替代物填充遗留的空隙，是维护腕关节生物力学特性和良好功能的关键。 目的：探讨自体骨膜包裹肌腱复合重组人骨形态发生蛋白2(recombinant human bone morphogenetic protein-2，rhBMP-2)与松质骨匀浆植入自体关节腔后的成骨和骨化机制，以及作为月骨替代物重建月骨的可行性。 方法：按随机数字法将45只新西兰白兔分成3组：骨膜包裹肌腱组、rhBMP-2组、单纯肌腱球对照组。分别以骨膜包绕肌腱团，1 mg rhBMP-2与游离肌腱、肌腱团块置入兔髌上囊。置入后3，6和9周取材，测量定量CT骨密度值，组织切片采用苏木精-伊红染色和免疫组织化学ABC法，在光镜下观察rhBMP-2分布。 结果与结论：移植物植入后，早期骨膜包裹肌腱组rhBMP-2染色阴性，9周时阳性，之后呈阴性，表明其骨化形成主要是在骨膜成软骨作用基础上的成骨过程，而无rhBMP-2的作用；rhBMP组显示rhBMP-2分布及骨化明显强于骨膜包裹肌腱组，且随时间延长逐渐加强，9周时呈强阳性，主要分布于新生骨细胞簇和新生软骨细胞簇及周围，之后随骨细胞成熟量增多而逐渐减弱。单纯肌腱球对照组玻璃样变，最终呈胶原状rhBMP-2染色始终阴性。各组各时间点定量CT骨密度值经统计学分析，除3周时骨膜包裹肌腱组、单纯肌腱对照组间无显著性差异(P > 0.05)，其余各组间差异均有显著性意义(P < 0.01)。自体骨膜包裹肌腱复合rhBMP-2及松质骨匀浆植入物在骨rhBMP-2及松质骨匀浆中rhBMP-2的诱导作用下可形成大量骨和软骨，有较强支撑作用，为其用作月骨替代物提供实验依据。 关键词：月骨；骨膜；重组人骨形态发生蛋白2；松质骨匀浆；修复重建     

骨髓脂肪细胞向成骨细胞的转分化

背景：骨髓脂肪细胞、成骨细胞共同来源于骨髓基质细胞,二者存在基因同源性,在一定的条件下可以相互转分化。 目的：观察骨髓细胞源性脂肪细胞在成骨诱导分化培养条件下转分化为成骨细胞的活性,探索股骨头坏死细胞水平治疗的新途径。 方法：将前脂肪细胞3T3-L1分别进行成骨诱导培养和成脂诱导培养。培养后不同时间点观察细胞形态的变化;并于诱导培养后5,21 d分别进行实时定量-聚合酶链反应检测成骨、成脂分化过程中,细胞中Runt相关基因转录因子2、氧化物增殖体激活物受体γ2、骨钙素和Ⅰ型胶原mRNA表达。并于成骨、成脂培养21 d后采用Wertern-blot法检测相关蛋白的表达。培养细胞爬片,分别进行碱性磷酸酶、钙结节茜素红、油红O染色,观察3T3-L1成骨转分化情况以及成骨细胞活性表达。 结果与结论：3T3-L1在成骨诱导培养5 d后,细胞由圆形逐渐演变成纺锤形和梭形;实时定量-聚合酶链反应检测结果与对照组相比,氧化物增殖体激活物受体γ2 mRNA表达减弱,而Runt相关基因转录因子2、骨钙素和Ⅰ型胶原mRNA表达微量增强。至21 d时,这种表达改变更加明显;Western-blot显示,Runt相关基因转录因子2、骨钙素和Ⅰ型胶原蛋白量增加,而氧化物增殖体激活物受体γ2微量甚至无表达;碱性磷酸酶染色阳性表达较多,茜素红钙结节染色可见多个散在分布的钙结节;油红O染色微量脂滴。提示小鼠骨髓基质细胞源性前脂肪细胞3T3-L1在成骨诱导培养下,可在一定程度上转分化为有生物活性的成骨细胞;小鼠骨髓基质细胞的脂肪细胞和成骨细胞二者之间存在着可塑性。     

转化生长因子β1中和抗体对转化生长因子β诱导肌腱胶原和术后粘连的影响

背景: 研究表明,转化生长因子β1在肌腱损伤愈合过程中增加了肌腱细胞胶原的合成和术后粘连的形成。 目的：观察转化生长因子β1抗体对转化生长因子β诱导的肌腱细胞胶原产生及术后粘连形成的影响。 设计、时间及地点：随机分组观察实验,于2005-09/2006-06在同济医学院实验动物中心完成。 材料：选择2~5月龄新西兰大白兔,体质量3.5~4.5 kg。转化生长因子由美国Santa Cruz B iotechnology公司提供。 方法：取兔屈指肌腱分离肌腱成纤维细胞、腱外膜细胞和腱内膜细胞,将细胞随机分成2组,实验组加入1 µg/L 转化生长因子β后,再加入0.1,0.5,1.0 mg/L转化生长因子β1中和抗体,对照组不添加任何试剂,酶联免疫吸附实验测定Ⅰ型胶原。取84只兔行中趾屈指肌腱切断吻合术,将其中36只兔随机分成3组,腱鞘内分别注入生理盐水、1.0,2.0 mg/L转化生长因子β1中和抗体,4,8周后取出肌腱行肌腱粘连检测、生物力学测定、组织学观察和扫描电镜观察;余48只兔随机分成2组,腱鞘内分别注入生理盐水和1.0 mg/L转化生长因子β1中和抗体,1,2,4,8周后取出肌腱,原位杂交方法测定肌腱转化生长因子β1和Ⅰ型胶原mRNA的表达。 主要观察指标：各组兔肌腱细胞胶原产生及术后粘连情况。 结果：酶联免疫吸附实验显示,转化生长因子β1能明显提高肌腱细胞Ⅰ型胶原的产生;转化生长因子β1抗体能降低3种细胞Ⅰ型胶原的产生,随抗体质量浓度增加,Ⅰ型胶原水平逐渐降低,且呈剂量依赖性;术后4,8周,与1.0,2.0 mg/L 转化生长因子β1组比较,生理盐水组屈趾肌腱滑动距离较短,模拟主动屈曲度明显受限(P < 0.05),最大抗断裂载荷各组间比较差异无显著性意义(P > 0.05)。扫描电镜和组织学观察结果显示,术后4,8 周生理盐水组胶原纤维排列紊乱,1.0,2.0 mg/L 转化生长因子β1组胶原纤维排列整齐。原位杂交结果显示,术后各时间点1.0 mg/L 转化生长因子β1组转化生长因子β1 和Ⅰ型胶原mRNA表达均低于生理盐水组(P < 0.05)。 结论：转化生长因子β1抗体能有效抑制转化生长因子β1在肌腱损伤修复中的作用,减少粘连形成。     

骨髓间充质干细胞成骨方向诱导过程中的基因表达

背景：目前骨髓间充质干细胞向成骨细胞分化演变中的基因表达模式尚不明确。 目的：观察骨髓间充质干细胞向成骨细胞诱导分化过程中碱性磷酸酶、骨桥蛋白、Ⅰ型胶原、碱性成纤维细胞生长因子和骨钙素基因的表达情况,验证骨髓间充质干细胞是否向成骨细胞成熟分化。 方法：抽取2月龄新西兰大白兔股骨骨髓,全骨髓贴壁法培养获得骨髓间充质干细胞,用矿化诱导培养基(DMEM/F12、地塞米松1×10-8 mmol/L、β-磷酸甘油钠0.01 mol/L、维生素C 0.05 g/L)进行成骨诱导培养,用反转录-聚合酶链反应方法检测诱导培养后第一二代骨髓间充质干细胞碱性磷酸酶、骨桥蛋白、Ⅰ型胶原、碱性成纤维细胞生长因子和骨钙素基因的表达情况,并对该骨髓间充质干细胞表面抗原CD44进行鉴定。 结果与结论：经矿化诱导培养基诱导培养后,第一二代骨髓间充质干细胞阶段性表达碱性磷酸酶、骨桥蛋白、Ⅰ型胶原、碱性成纤维细胞生长因子和骨钙素基因;第1代骨髓间充质干细胞抗原CD44阳性率达44.4%。提示兔骨髓间充质干细胞在体外矿化诱导培养中逐渐向成骨细胞分化,分别于诱导后第一二代细胞中阶段性顺序表达成骨细胞特异性基因碱性磷酸酶、骨桥蛋白、Ⅰ型胶原、碱性成纤维细胞生长因子和骨钙素,该细胞已具备成骨细胞特征,为揭示骨髓间充质干细胞向成骨细胞分化过程中基因表达机制提供了实验依据。     

骨形态发生蛋白2对移植肌腱在骨隧道内愈合的影响：界面组织学特点★

目的: 前交叉韧带重建移植肌腱在骨隧道内多为间接愈合，即在肌腱与骨之间没有纤维软骨带而直接由Sharpey’s纤维固定。观察人重组骨形态发生蛋白2对移植肌腱在骨隧道内愈合的影响。 方法：实验于2004-06/09在上海市第六人民医院动物实验室完成，动物实验方法符合动物伦理学要求。①实验材料及分组：选用新西兰大白兔36只，按随机数字表法分为3组，即空白对照组、胶原海绵组及骨形态发生蛋白2组，每组12只。②实验方法：采用兔膝关节自体半腱肌重建前交叉韧带悬吊固定模型，骨形态发生蛋白2组在骨隧道内加入人重组骨形态发生蛋白2和胶原海绵，胶原海绵组仅在骨隧道内加入胶原海绵。③实验评估：术后4，8，12周在移植物周围取材进行苏木精-伊红、天狼猩红和Masson染色，观察骨隧道和肌腱移植物间的界面组织学变化，采用Yamakado分类评价界面形态愈合类型，并对Masson染色切片作肌腱周围新骨形成的形态学定量评估。 结果：空白对照组2只白兔于术后第10周脱失。①术后4周空白对照组腱骨间有腱-骨分离，骨形态发生蛋白2组腱-骨间充满结缔组织；术后8周骨形态发生蛋白2组形成Sharpey’s纤维，而空白对照组术后12周时开始出现Sharpey’s纤维。②术后4，8，12周骨形态发生蛋白2组白兔新骨形成面积均显著大于空白对照组、胶原海绵组（P < 0.01）。 结论：人重组骨形态发生蛋白2可促进移植肌腱在骨隧道内的愈合，促进腱-骨之间形成间接连接。     

重组碱性成纤维细胞生长因子/I型胶原复合材料修复兔半月板无血运区软骨损伤

摘要 背景：单独应用重组碱性成纤维细胞生长因子对无血运区半月板损伤的愈合无明显影响,考虑主要与其在体内易被吸收和降解等有关。近年来Ⅰ型胶原作为生物性载体的应用逐渐增多。 目的：观察重组碱性成纤维细胞生长因子/Ⅰ型胶原复合材料修复兔半月板软骨损伤的效果。 方法：选用健康新西兰大白兔36只,首先在兔半月板上造成统一的无血运区损伤模型。随机分为空白对照组、重组碱性成纤维细胞生长因子组和重组碱性成纤维细胞生长因子/Ⅰ型胶原组。术后2,6,12周分批处死实验动物,进行大体形态观察和组织学检查。 结果与结论：重组碱性成纤维细胞生长因子组对无血运区损伤愈合无明显影响,但对半月板边缘滑膜中成纤维细胞有明显的促增殖作用;重组碱性成纤维细胞生长因子/Ⅰ型胶原组表现为纤维软骨样组织愈合,但其愈合组织与正常半月板组织仍有差异。结果表明应用重组碱性成纤维细胞生长因子/Ⅰ型胶原复合型材料治疗半月板无血运区的损伤是一种有效的治疗方法。 关键词：半月板;软骨;损伤;重组成纤维细胞生长因子;I型胶原 doi:10.3969/j.issn.1673-8225.2010.34.006     

富血小板血浆诱导犬骨髓间充质干细胞的体外成骨*

背景：富血小板血浆中含有大量骨再生所需的生长因子,且各生长因子的比例是机体自身形成的,具有良好的协同作用。 目的：探讨富血小板血浆体外诱导犬骨髓间充质干细胞成骨的效果。 设计、时间及地点：细胞学体外观察,于2007-06/2008-02在中南大学湘雅医院中心实验室完成。 材料：健康12月龄雄性比格犬,由中南大学湘雅医学院实验动物部提供。 方法：收集第3代犬骨髓间充质干细胞,分为4组：对照组加入标准培养基;成骨诱导培养基组向培养板孔内加入含胎牛血清、地塞米松、β-甘油磷酸钠、维生素C的高糖DMEM培养基;富血小板血浆组根据预实验结果,向培养板内加入含体积分数为6.25%富血小板血浆的低糖DMEM培养基;联合组向培养板内加入含地塞米松、β-甘油磷酸钠、维生素C、体积分数为6.25%富血小板血浆的高糖DMEM培养基。 主要观察指标：细胞内碱性磷酸酶活性,免疫细胞化学染色检测Ⅰ型胶原的表达,改进Von Kossa染色标记钙结节形成情况,RT-PCR检测诱导后骨钙素mRNA的表达。 结果：各组碱性磷酸酶活性均随诱导时间的延长而逐渐增高,联合组升高幅度最为明显(P < 0.05)。诱导7,14 d后,成骨诱导培养基组、联合组Ⅰ型胶原均呈阳性表达,富血小板血浆组、对照组Ⅰ型胶原始终呈阴性表达。诱导14 d后,成骨诱导培养基组、联合组可见卵圆形钙结节。诱导7,14 d后,对照组与富血小板血浆组之间骨钙素mRNA表达水平无明显差异(P > 0.05),此2组骨钙素mRNA表达水平均明显低于成骨诱导培养基组、联合组(P < 0.05);成骨诱导培养基组骨钙素mRNA表达水平明显低于联合组(P < 0.05)。 结论：经成骨条件培养基诱导培养的骨髓基质干细胞,富血小板血浆能在体外显著诱导其成骨指标的表达。     

绝经后妇女骨代谢过程中血清基质金属蛋白酶3和骨桥蛋白的变化

背景：骨桥蛋白和基质金属蛋白酶3具有高度的亲和力,此二者的表达可能与骨代谢有关。 目的：观察绝经后妇女血清基质金属蛋白酶3和骨桥蛋白水平,并观察其与骨保护蛋白、骨保护蛋白配体及骨代谢指标的关系。 方法：将120名绝经后妇女分为骨密度正常组、低骨量组和骨质疏松组3 组,对其血清基质金属蛋白酶3、骨桥蛋白、骨保护蛋白、骨保护蛋白配体及骨碱性磷酸酶、骨钙素、Ⅰ型胶原交联C端肽和尿Ⅰ型胶原交联N端肽进行测定,计算骨桥蛋白/基质金属蛋白酶3比值。 结果与结论：骨质疏松组中血清骨桥蛋白和基质金属蛋白酶3的水平高于正常组(P < 0.05)。绝经后妇女血清基质金属蛋白酶3、骨桥蛋白和骨桥蛋白/基质金属蛋白酶3比值与血清骨保护蛋白配体、骨碱性磷酸酶和骨钙素水平呈明显负相关 (P < 0.05),与骨保护蛋白、尿尿Ⅰ型胶原交联N端肽/肌酐比值呈明显正相关性(P < 0.05)。骨质疏松组中血清基质金属蛋白酶3、骨桥蛋白和骨桥蛋白/基质金属蛋白酶3比值与血清骨保护蛋白配体、骨碱性磷酸酶和骨钙素水平呈明显负相关 (P < 0.05),与骨保护蛋白、尿尿Ⅰ型胶原交联N端肽/肌酐水平比值存在明显正相关性(P < 0.05)。提示绝经后妇女血清骨桥蛋白水平和骨桥蛋白/基质金属蛋白酶3比值升高与绝经后骨质疏松症伴随骨代谢转换过程增快有关。     

大鼠胫骨骨折愈合过程中Ⅰ，Ⅱ型胶原蛋白的表达：失神经状态下Western blot方法测定

背景: 近年来大量的实验及临床观察均证实神经因素对骨折愈合有调节和支配作用。Ⅰ型胶原是促成骨细胞分化和增强成骨细胞黏附能力主要因素，是组成骨构架的基质蛋白；而Ⅱ型胶原由软骨细胞产生。 目的：观察失神经状态下骨折愈合过程中Ⅰ，Ⅱ型胶原蛋白表达的变化规律。 设计、时间及地点：随机对照动物实验，于2005-05/12在解放军第二军医大学动物实验室及细胞生物教研究室完成。 材料：选用3月龄健康雄性SD大鼠40只，采用随机数字表法分为2组，单纯胫骨骨折组与脊髓损伤并胫骨骨折组各20只。 方法：单纯胫骨骨折组大鼠于从左胫骨平台前缘插入1根φ0.8 mm克氏针，制成胫骨骨折模型。脊髓损伤并胫骨骨折组在植备上述模型的基础上，横断切除T10 段脊髓约0.3 cm，制成T10脊髓完全性损伤大鼠胫骨骨折模型。 主要观察指标：分别于伤后1，2，4，5周采用Western blot法检测两组大鼠骨折断端骨痂中Ⅰ，Ⅱ型胶原的蛋白表达。 结果：伤后第1周两组大鼠骨折断端骨痂中Ⅰ，Ⅱ型胶原均有表达，脊髓损伤并胫骨骨折组两种胶原的表达程度均高于单纯胫骨骨折组(P < 0.05)；伤后第2周脊髓损伤并胫骨骨折组Ⅱ型胶原的表达量达到峰值，高于单纯胫骨骨折组(P < 0.05)；伤后第4周单纯胫骨骨折组Ⅰ型胶原表达量达峰值，高于脊髓损伤并胫骨骨折组(P < 0.05)，脊髓损伤并胫骨骨折组Ⅱ型胶原仍有高表达；伤后第5周两组Ⅰ，Ⅱ型胶原表达量均下降。 结论：失神经状态下骨折愈合过程中Ⅰ、Ⅱ胶原的分泌规律与正常骨折愈合一致，区别在于各时间点尤其是在峰值点上表达量有明显差异。     

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 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.     

Treatment Considerations in Anticonvulsant Monotherapy

Summary: The long-standing practice of polypharmacy in treating epilepsy is giving way to use of monotherapy. Monotherapy can improve seizure control as well as reduce the risk of serious idiosyncratic reactions, dose-related side effects, and complex drug interactions. Monotherapy also offers improved compliance and cost-effectiveness. The basis of monotherapy is accurate diagnosis and assessment of the patient's seizure type(s), followed by selection of a single appropriate anticonvulsant drug. Many patients currently treated with multiple anticonvulsants can be successfully converted to monotherapy with a carefully monitored program in which troublesome and redundant drugs are gradually withdrawn from the therapeutic regimen.     

Anticonvulsant Drugs and Cognitive Function: A Review of the Literature

Summary: Alterations of cognitive function are separate from disturbances of behavior seen in association with epilepsy. The nature of the cognitive disability may to a certain extent depend on the seizure type. Partial seizures, mainly derived from a temporal lobe focus, impair memory tasks, while generalized seizures seem to have more effect on attentional abilities. A number of studies, reviewed in this paper, suggest that anticonvulsant drugs further impair cognitive function. Maximal impairments are seen in patients receiving polytherapy: rationalization of polytherapy improves cognitive abilities. Studies in children and adults have allowed differentiation of the effects of various commonly used antiepileptic agents. Maximal cognitive deficits are seen with. phenytoin, while phenobarbital and sodium valproate induce moderate disturbances, and carbamazepine seems relatively free from such toxicity. Further research is needed on the interrelationship between types of seizure disorders, types of anticonvulsant medications, and cognitive function.     

Dextromethorphan: Cellular Effects Reducing Neuronal Hyperactivity

Summary: Dextromethorphan is a dextrorotary morphinan without affinity for opioid receptors, commonly used as an antitussive medication. During the past 5 years, interest in the compound and its demethylated derivative, dextrorphan, has been revived because additional neuroprotective and an-tiepileptic properties were found in in vitro studies, animal experiments, and a few clinical cases. Both morphinans are able to inhibit N -methyl-D-aspartate (NMDA) receptor channels and voltage-operated calcium and sodium channels with different potencies. The inhibition of the NMDA receptor is believed to be the predominant mechanism of action responsible for the anticonvulsant and neuroprotective properties of the compounds.