第3~12周人胚肝甲胎蛋白及细胞角蛋白19和c-Met的时空表达

背景：现阶段对于肝干细胞在胚胎肝发育过程中的形态学特征、时空分布、分化过程的报道很少。 目的：以甲胎蛋白、细胞角蛋白19、c-Met作为标志物,观察其在不同发育阶段肝干细胞中的时空分布。 设计、时间及地点：细胞学体外观察,于2005-06/2006-12在潍坊医学院中心实验室完成。 材料：40例胚胎标本取自3个月内的流产胎儿,由潍坊医学院附属医院提供。 方法：收集流产胚胎,30 min内制作切片,显微镜下根据胚层形成情况、体节数目及器官发育状况确定胎龄。选择胎龄第3~12周的标本切片,每隔10张抽出1张切片,行免疫组织化学染色。 主要观察指标：第3~12周胚胎肝干细胞甲胎蛋白、c-Met、细胞角蛋白19的表达。 结果：第3~5周甲胎蛋白、c-Met呈阳性反应,提示为肝干细胞;第10~12周甲胎蛋白、c-Met阳性细胞主要分布于汇管区周围,提示此时肝干细胞主要局限于汇管区周围的肝索内,与成年肝中卵圆细胞(成年肝干细胞)的分布一致。细胞角蛋白19阳性反应在第7周时开始出现;第10~11周时细胞角蛋白19阳性反应主要位于汇管区附近的肝索细胞和胆管板细胞及胆管上皮细胞;第12周时细胞角蛋白19阳性信号仅见于胆管板和胆管上皮细胞。此时所有的胆管板细胞及胆管上皮细胞均呈甲胎蛋白、c-Met和细胞角蛋白19阳性。 结论：细胞角蛋白19在肝干细胞中无表达,仅在胆管上皮细胞及其祖细胞中有表达,可能不适合作为肝干细胞的标志物。所有的胆管板及胆管上皮细胞均呈甲胎蛋白、c-Met、细胞角蛋白19阳性反应,推测甲胎蛋白+/c-Met+/细胞角蛋白19+的细胞可能为胆管祖细胞。     

胚胎干细胞源性肝干细胞肝内移植对宿主肝功能的影响及安全性评估**☆

背景：体外诱导胚胎干细胞分化为肝细胞已有不少成功的报道，但其体内移植后能否有效整合入宿主肝板、在肝内能否进一步生长分化并表达肝细胞功能以及成瘤的风险等情况目前还不清楚。 目的：应用治疗性肝再生模型进行胚胎干细胞源性肝干细胞肝内移植, 观察其在肝组织替代、体内的生长分化及成瘤性情况。 设计：随机对照动物实验。 单位：中山大学附属第二医院小儿外科。 材料：选用BALB/c小鼠24只为受体，鼠龄6~8周，体质量20~ 35 g，雌雄不拘购自广州市实验动物中心。实验所用胚胎干细胞源性肝干细胞由作者所在课题组诱导胚胎干细胞分化而成。小鼠胚胎干细胞株E14由本院干细胞中心提供。 方法：实验于2006-07/2007-06在中山大学附属第二医院干细胞研究中心完成。将24只小鼠随机分为2组：肝再生模型+干细胞移植组和肝切除+干细胞移植组，每组12只。前组分两次按50 mg/kg剂量腹腔内注射倒千里光碱(retrorsine) ，间隔2周，第2次注射4周后行70%肝部分切除制造肝损伤；然后经门静脉分别移植1×105羟基荧光素乙酰乙酸（CFDA-SE）荧光标记的细胞入小鼠肝内进行胚胎干细胞源性肝干细胞移植。后组在行70%肝部分切除制造肝损伤模型后进行胚胎干细胞源性肝干细胞移植。 主要观察指标：荧光显微镜下观察移植细胞组受体鼠肝脏内分布、整合与体内生长分化情况。2周后行白蛋白荧光免疫组化(双荧光染色)、血清白蛋白水平检测其功能状况。将胚胎干细胞源性肝干细胞注入治疗性肝再生小鼠肝内，将未分化的胚胎干细胞移植入小鼠腋区皮下作为对照，观察胚胎干细胞源性肝干细胞体内成瘤情况。 结果：①肝干细胞在受体鼠肝内生长情况：CFDA SE标记的胚胎干细胞源性肝干细胞肝内移植1周，受体小鼠肝实质内可见散在绿色荧光分布。2周后，肝实质内绿色荧光分布区域明显扩大，且可见类似肝索样结构排列。②肝功能：共焦白蛋白荧光免疫组化(双荧光染色)结果表明，受体小鼠肝组织内可见标记细胞表达白蛋白阳性信号（呈黄色荧光），肝再生模型+干细胞移植组和肝切除+干细胞移植组血清白蛋白水平则无明显差异（P > 0.05）。③肝干细胞移植安全性：6周内未见畸胎瘤形成，而将未分化的胚胎干细胞移植入小鼠腋区皮下6周后则可见畸胎瘤形成。 结论：胚胎干细胞源性肝干细胞移植入治疗性肝再生模型小鼠肝内后可有效在肝内能进一步生长分化并部分表达肝细胞功能；且此移植安全性较好。     

小鼠胚胎肝干细胞体外向肝样细胞的诱导分化

背景：目前肝干细胞尚无特异性标志物,故其分离、培养尤其是纯化技术尚不成熟。 目的：观察体外培养的小鼠胚胎肝干细胞生物学特性,及其向肝样细胞的诱导分化能力。 设计、时间及地点：细胞学体外观察,于2008-01/06在厦门大学附属中山医院消化中心实验室完成。 材料：SPF级BALB/c胎鼠20只,13.5 d龄,由厦门大学生命科学学院实验动物中心提供。 方法：无菌操作取出胎鼠肝脏,用细胞刮梳理后用IV型胶原酶消化。取分离纯化后的第2代细胞进行免疫荧光染色。细胞培养到第3代时,分别用3 mmol/L丁酸钠盐与0.1% DMSO进行诱导,5 d后收集细胞进行Western blotting实验。 主要观察指标：胚胎肝干细胞的形态及表面分子的表达,诱导后胚胎肝干细胞mRNA与蛋白水平的变化。 结果：分离培养的细胞第2代即可得以纯化,呈克隆样生长,高表达白蛋白、甲胎蛋白、C-met及角蛋白19,且多数细胞共表达白蛋白与角蛋白19、C-met与角蛋白19,双阳性率约80%。细胞诱导后肝细胞标志物白蛋白表达明显增加,而作为不成熟肝细胞的经典标志物甲胎蛋白表达减少,同时干细胞标志物 c-kit mRNA水平也明显下降,角蛋白19水平无明显变化。 结论：胚胎肝干细胞具有双向分化潜能,经丁酸钠盐与DMSO诱导后可以向肝样细胞分化。     

原发性肝癌不同病理组织类型中肝干细胞的分析***

背景：近年来,有观点认为原发性肝癌的发生机制可能为肝干细胞分化不全或分化异常所致。目前,肝干细胞研究正处于起步阶段,对人原发性肝癌的“干细胞起源”学说尚需进一步验证。 目的：观察原发性肝癌不同病理组织类型中肝干细胞的活化、分布、来源和免疫表达特征。 设计：观察对比实验。 单位：解放军第三军医大学大坪医院野战外科研究所肿瘤中心。 对象： 实验于2003-09/2004-07在解放军第三军医大学大坪医院野战外科研究所肿瘤中心完成,选用94例肝细胞癌和12例肝内胆管细胞癌和10例混合型肝癌石蜡包埋组织,同时选用5例肝硬化和4例正常肝组织作为实验对照,均取自病理科存档资料。肝癌组织均为患者首次肝癌切除手术时采取,包括肿瘤组织和癌旁组织,患者均无化疗和放射治疗史,并对受检项目知情同意。实验主要抗体均购自Santa Cruz公司。 方法： 采用苏木精-伊红染色、免疫组织化学SP方法（检测的免疫标志有鼠抗人细胞角蛋白19单克隆抗体、鼠抗人细胞角蛋白7单克隆抗体、鼠抗人细胞角蛋白8&18单克隆抗体、鼠抗人c-kit单克隆抗体、鼠抗人Thy-1单克隆抗体、鼠抗人甲胎蛋白单克隆抗体）观察各病变类型肝干细胞免疫标志表达情况。 主要观察指标：各病变类型肝干细胞免疫标志表达情况。 结果：在原发性肝癌不同病理组织类型中干细胞免疫标志均有不同程度的表达,均可观察到肝干细胞向肝癌细胞的转化,以混合型肝细胞癌中肝干细胞免疫表型表达率最高(P < 0.05)。正常组和肝硬化组干细胞免疫表型特征为阴性。　 结论：不同病理组织类型的肝癌组织中均存在不同分化状态和不同来源的肝干细胞。     

体外诱导大鼠骨髓干细胞向肝干细胞分化的特征**★

目的：骨髓干细胞分化为肝干细胞的发现具有重要的临床应用价值,可用其作为生物人工肝或肝细胞移植的供体细胞,以解决供体缺乏，同时自体细胞还可免除异基因或异种细胞所致的许多问题。为此，实验模拟肝脏发育的微环境，观察体外诱导分化大鼠骨髓干细胞为肝干细胞的可行性及特征。 方法：实验于2006-10/2007-08在解放军第一二三医院南京军区肝病中心实验室完成。①实验动物: SPF级SD大鼠，2月龄，体质量（200±20） g,雌雄不拘，购于上海斯莱克实验动物公司。实验过程中对动物处置符合动物伦理学标准。②实验方法：采用密度梯度分离法分离培养大鼠骨髓干细胞，并设诱导组和非诱导组，应用25 μg/L肝细胞生长因子、10 μg/L成纤维生长因子-4、10 μg/L干细胞生长因子共同诱导。③实验评估：于诱导第0，7，14，21，28天，观察细胞形态变化，采用放射免疫法检测培养上清液中甲胎蛋白浓度，免疫组织化学染色检测甲胎蛋白、细胞角蛋白19、白蛋白的表达，应用流式细胞仪检测甲胎蛋白、细胞角蛋白19表达阳性细胞比例。 结果：①诱导培养的骨髓干细胞呈卵圆形或圆形的肝干细胞样改变。②放射免疫法检测到诱导组细胞甲胎蛋白浓度逐渐升高，第14天达高峰，随后呈下降趋势，与非诱导组相比，除第0，7天无差异，其余各时间点差异均显著（P < 0.05）。③免疫细胞化学法检测到诱导组细胞特异性表达甲胎蛋白、细胞角蛋白19及白蛋白，非诱导组不表达3种蛋白。④流式细胞分析诱导组甲胎蛋白阳性细胞比例为66.20%、细胞角蛋白19阳性细胞的比例为44.96%。 结论：在实验建立的诱导培养体系中，骨髓干细胞在体外能分化为肝干细胞样细胞，诱导细胞有分泌甲胎蛋白、细胞角蛋白19、白蛋白的特征性功能。     

胎儿骨髓源性胚胎后亚全能干细胞分离培养及向肝细胞的诱导分化★◆

背景：目前研究认为在胚胎发育后的多种组织中存在一类干细胞群体，可分化为不同胚层的组织细胞；但又不同于胚胎干细胞，随着妊娠期间胚胎的发育胚胎干细胞会逐渐失去部分分化潜能，会出现一些特殊表型或分子标记，如CD105，称其为胚胎后亚全能干细胞。 目的：根据胚胎后亚全能干细胞表达CD105的特性分离胎儿骨髓源性胚胎后亚全能干细胞，经体内外诱导使其分化为肝细胞样细胞并检测其功能。 设计、时间及地点：动物随机分组，细胞分子生物学实验，于2003-03/2005-03在天津市第三中心医院卫生部人工细胞工程技术研究中心完成。 材料：取22周龄左右胎儿股骨和胫骨骨髓分离出胚胎后亚全能干细胞。以雌性成年SCID鼠作为干细胞移植的受体。CD105免疫磁珠为德国Miltenyi Biotec产品。鼠抗人白蛋白抗体为美国Sigma产品。碱性成纤维细胞生长因子、肝细胞生长因子为英国PEPROTECH产品。 方法：利用密度梯度离心结合免疫磁珠方法分离胎儿骨髓CD105（+）胚胎后亚全能干细胞，体外培养，用含30 μg/L肝细胞生长因20 μg/L碱性成纤维细胞生长因子的诱导培养基将其向肝细胞样细胞诱导分化。将24只SCID鼠随机分为干细胞治疗组和对照组，每组12只，均按800 mg/kg的剂量向腹腔内注射D-氨基半乳糖制备肝损伤模型。造模次日，干细胞移植组鼠在肝原位输注106左右CD105（+）细胞，对照组分别输注106左右的CD105(-)细胞或同等体积的培养液。 主要观察指标：于干细胞移植后2，7 d，1，3个月对肝脏组织行免疫组化检测人源白蛋白表达。 结果：免疫磁珠筛选后的细胞免疫细胞化学检测CD105呈弱阳性表达；细胞在对数生长期的倍增时间为30 h左右；约传10代后进入衰退期。SCID鼠移植胚胎后亚全能干细胞3个月后在小鼠肝脏中可见有点状或小灶状的人白蛋白表达，对照组未见表达。 结论：来源于胎儿骨髓的胚胎后亚全能干细胞可以在肝脏微环境下转化为肝细胞样细胞。     

小鼠胎肝干细胞的分离培养与鉴定

背景：胎肝细胞可能具有比骨髓干细胞等更强的增殖分化能力和更低的免疫原性，但目前涉及胎肝干细胞直接分离、培养的报道甚少。 目的：拟在体外分离培养小鼠胎肝干细胞，并对其生物学特性进行初步鉴定。 设计、时间及地点：细胞学体外观察，于2008-03/06在重庆市神经病学重点实验室完成。 材料：SPF级13.5 d龄昆明种胎鼠9只，由重庆医科大学实验动物中心提供。 方法：采用胶原酶+EDTA联合消化法与差速贴壁法体外分离胎鼠肝干细胞，按2×108 L-1接种，待细胞80%~90%汇合后消化传代。采用链霉亲和素-生物素-过氧化酶复合物技术对原代接种后5 d的贴壁细胞进行多种肝干细胞表面标志物的标记。 主要观察指标：原代胎肝干细胞形态变化，胎肝干细胞的传代扩增情况，胎肝干细胞表面标志的表达。 结果：原代培养24 h细胞贴壁，呈致密圆形，边缘清楚；3 d左右部分细胞呈梭形，7 d后细胞铺展呈上皮样；传代后细胞扩增速度无明显变化，至第5代仍保持较均一的上皮细胞状。原代接种后5 d的贴壁细胞，人干细胞因子受体与甲胎蛋白呈阳性表达，白蛋白与细胞角蛋白19呈阴性。 结论：胎肝干细胞原代培养早期表达甲胎蛋白与人干细胞因子受体，不表达白蛋白和细胞角蛋白19，提示所分离的胎肝干细胞可能是一种较原始的干细胞，尚处在未分化的早期阶段。     

肝纤维化大鼠血清体外诱导骨髓间充质干细胞向肝细胞的分化

背景：近年来临床运用骨髓间充质干细胞移植治疗晚期肝纤维化取得了较好疗效,但由于肝源稀少,骨髓干细胞体外分化为成熟肝细胞的技术仍然不成熟。 目的：探讨骨髓间充质干细胞体外诱导其分化为肝细胞的可行性。 方法：构建大鼠肝纤维化模型,分离、纯化并鉴定大鼠骨髓间充质干细胞,制备正常及肝纤维化大鼠血清,取第3代骨髓间充质干细胞分组培养,分别加入以下培养基：DMEM+体积分数10%胎牛血清;肝细胞生长培养基(HGM)+体积分数5%胎牛血清;HGM+5%正常大鼠血清;HGM+5%肝纤维化大鼠血清;HGM+5%肝纤维化大鼠血清+25 μg肝细胞生长因子。观察各组细胞形态变化,MTT法测定细胞生长曲线,采用Realtime-PCR检测甲胎蛋白和细胞角蛋白18的表达,溴甲酚绿法检测上清液中白蛋白水平,ELISA法检测培养上清液中转化生长因子β1表达。 结果与结论：正常大鼠血清能促进骨髓间充质干细胞的增殖;肝纤维化大鼠血清对骨髓间充质干细胞促增殖作用最好,且能有效诱导其向肝细胞分化,联合使用肝细胞生长培养基能提高分化率。     

肝细胞生长因子诱导骨髓间充质干细胞表达甲胎蛋白和白蛋白

背景：对于诱导骨髓间充质干细胞成肝细胞样细胞的研究,在大鼠及小鼠及人类中已有相关报道。甲胎蛋白和白蛋白均为肝细胞系较为特异的标志。 目的：进一步验证肝细胞生长因子对骨髓间充质干细胞的诱导分化作用。 方法：采用密度梯度离心和贴壁培养法相结合分离培养人骨髓间充质干细胞,以含20 μg/L 肝细胞生长因子和10 μg/L 碱性成纤维细胞生长因子的低糖DMEM培养基诱导培养,对照组取同代细胞,常规培养液培养。诱导培养7,14,21和28 d采用免疫组织化学方法检测甲胎蛋白和白蛋白的表达及RT-PCR技术检测白蛋白 mRNA表达。 结果与结论：诱导组骨髓间充质干细胞呈类上皮样细胞。诱导组在培养7 d时,甲胎蛋白表达阳性率为81.5%,随着培养时间延长,甲胎蛋白阳性表达率逐渐减弱,而白蛋白阳性表达率及白蛋白mRNA表达逐渐增强,至培养28 d,白蛋白阳性表达率达91.2%,对照组细胞均无白蛋白、白蛋白mRNA及甲胎蛋白表达。结果证实,肝细胞生长因子可诱导骨髓间充质干细胞表达甲胎蛋白和白蛋白。     

骨髓源干细胞参与的血管内皮更新*☆

背景：研究表明骨髓源干细胞可塑性强,但其参与组织更新及修复的机制在转分化及细胞融合间尚存在争议。 目的：通过性别交叉骨髓移植建立雌雄嵌合体小鼠模型,观察骨髓源性干细胞是否参与内皮细胞的更新并探讨其可能的机制。 方法：采用雌性C57BL/6-GFP小鼠为供体,雄性C57BL/6小鼠为受体进行骨髓移植建立嵌合体小鼠,并应用流式细胞术分析骨髓嵌合情况。骨髓移植后20周采用Y染色体荧光原位杂交法对脑、肾、肝、脾及心脏组织Y染色体进行标记,荧光显微镜观察各组织器官中血管内皮细胞Y染色体及绿荧光蛋白表达情况。 结果与结论：①嵌合体小鼠骨髓细胞流式细胞学检测显示移植骨髓后1周骨髓GFP+细胞为(7.48±1.38)%、4周时达(73.92±5.57)%,结果表明成功建立性别交叉骨髓移植模型。②骨髓移植后20周嵌合体小鼠脑、肾、肝和脾组织血管壁可见绿荧光蛋白表达,且部分细胞同时表达Y染色体,表明发生骨髓源细胞和血管内皮细胞融合。脑实质及心肌组织未见绿荧光蛋白表达。结果提示骨髓源干细胞可能通过细胞融合机制参与不同组织器官中血管内皮细胞的更新。     

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.     

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.     

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.     

Effects of NMD A- and AMPA-Receptor Antagonists on Different Forms of Epileptiform Activity in Rat Temporal Cortex Slices

Summary: Lowering extracellular magnesium induces different patterns of epileptiform activity in rat hippocampus and entorhinal cortex. Short recurrent epileptiform discharges in the hippocampus are stable over time, whereas seizurelike events (SLEs) in the entorhinal cortex, the subiculum, and the neighboring neocortex develop into late recurrent discharges which are not blocked by clinically employed antiepileptic drugs. We tested the sensitivity of the different epileptiform discharge patterns to. /V-methyl-D-aspartate (NMDA)- and non-NMDA-receptor antagonists. As NMDA-receptor antagonist we used dextrorphan, ket-amine, and 2-aminophosphonovalerate (2APV); as α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA)-receptor antagonist we employed the quinoxaline derivative glutamate 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX). The findings show that the different patterns of epileptiform activity, including the late recurrent discharges, are sensitive to all NMDA-receptor antagonists. However, when dextrorphan was employed to suppress seizure-like events, later recurrent discharges did not develop during the remaining time course of the experiment. CNQX reversibly suppressed recurrent discharges in the hippocampus and SLEs in the entorhinal cortex. However, late recurrent discharges become insensitive to CNQX, even at a high concentration of 60 μM m. This finding suggests a prominent role for NMDA receptors in the generation of late recurrent discharges.     

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.     

The influence of comorbid depression on seizure severity

PURPOSE: To determine the relation between depressive symptoms and seizure severity among people with epilepsy. METHODS: A postal questionnaire was used to survey a nationwide community sample about seizures and depression. The Seizure Severity Questionnaire (SSQ) assessed the severity and bothersomeness of seizure components. The Centers for Epidemiological Studies-Depression scale categorized levels of depression. RESULTS: Respondents categorized as having current severe (SEV, n = 166), mild-moderate (MOD, n = 74), or no depression (NO, n = 443) differed significantly in SSQ scores (all p < 0.0001). People with SEV or MOD reported significantly worse problems than did those with NO depression for overall seizure recovery (mean, 5.3, 4.9, 4.5, respectively); overall severity (5.0, 4.5, 4.2); and overall seizure bother (5.3, 4.8, 4.4) (all p < 0.005). Cognitive, emotional, and physical aspects of seizure recovery also were rated worse among people with SEV than with NO depression (all p < 0.05). Symptoms of depression were significantly correlated with higher levels of all components of generalized tonic-clonic seizure severity (r = 0.33-0.48; all p < 0.0001), and partial seizures (r = 0.31-0.38; all p < 0.01). CONCLUSIONS: Clinically depressed people with epilepsy reported higher levels of perceived severity and bother from seizures, as well as greater problems with overall seizure recovery than did nondepressed people experiencing similar types of seizures. The pervasive influence of depressive symptoms on reports of seizure activity suggests that people with epilepsy should be screened for depression. These data highlight the importance of detecting and treating depression among people with epilepsy.     

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.