Alzheimer病患者淀粉样前体蛋白基因16、17外显子突变的研究

目的 探讨淀粉样β-蛋白(β/A_4)基因突变与Alzheimer病(AD)的关系。方法 运用限制性片段长度多态性(RFLP)和单链构象多态性(SSCP),检测分析20例散发性AD患者和8例正常老年人的淀粉样前体蛋白(APP)基因16、17外显子的多态性。结果 AD患者和正常对照的β/A_4基因均未发现C→T突变及其它异常SSCP泳动变位。结论 APP基因β/A_4编码区突变不是一突变“热点”,在AD不具有普遍意义。     

线粒体基因突变对氧化磷酸化的影响及其在阿尔茨海默病发病中的意义

近年研究发现，阿尔茨海默病(AD)患者线粒体细胞色素氧化酶(COX)活性选择性降低，部分患者特异性存在线粒体DNA(mtDNA)COX基因突变。我们于2000～2002年以AD胞质杂交细胞(cybrid)为实验模型，观察mtDNA基因突变对线粒体氧化磷酸化(OXPHOS)及β-淀粉样蛋白(AB)产生、神经原纤维缠结(NFT)形成和神经元凋亡的影响，探讨mtDNA基因突变在AD发病中的意义。     

胰岛素降解酶基因与阿尔茨海默病的关系

阿尔茨海默病(AD)是老年人智能损害的最常见原因,β淀粉样蛋白毒性学说是其发病机制中的主要学说.胰岛素降解酶(IDE)可以降解胰岛素和β淀粉样蛋白,因此与2型糖尿病和AD密切相关.IDE基因位于10号染色体上,调控着β淀粉样蛋白的降解与清除.近来的研究提示IDE基因与散发性AD相关.本文就IDE基因与AD的关系作一综述.     

脱氧核糖核酸甲基化在阿尔茨海默病发病机制中的研究进展

阿尔茨海默病(Alzheimer's disease,AD)是一种以进行性认知功能障碍和行为损害为特征的中枢神经系统退行性病变,其典型病理改变是β-淀粉样蛋白(arnyloid-β,Aβ)沉积形成的老年斑和异常过度磷酸化tau蛋白形成的神经原纤维缠结.然而至今,AD的发病机制尚未完全清楚.流行病学研究表明,AD是遗传因素和环境因素共同作用的结果.近年来,随着脱氧核糖核酸(DNA)甲基化研究的逐步深入,越来越多的证据表明DNA甲基化与AD关系密切.其中与早发家族性AD相关的β淀粉样前体蛋白(β-amyloid precursor protein,APP)、早老素l、早老素2[1]及迄今为止惟一一个在多个不同种群中被证实了的主要AD风险因子ApoE等位基因(e)4[2]均在AD中发生了异常甲基化改变.异常的DNA甲基化通过影响基因的转录,进而影响相应蛋白的表达,产生相关病理变化.随着世界人口老龄化进程的加快,AD患病率呈逐年上升趋势,不仅给个人带来了极大的痛苦,而且给家庭和社会带来沉重负担,因此,明确AD的病理机制对未来AD的诊断及治疗有着重要的意义.现就近年来DNA甲基化在AD发病机制研究中所取得的进展做一综述.     

Alzheimer病患者线粒体DNA点突变的研究

目的旨在观察Alzheimer病(Alzheimerdisease,AD)患者线粒体DNA(mitochondrialDNA,mtDNA)上点突变的情况,并探讨mtDNA点突变与AD发生的关联性。方法入组了111例AD患者作为AD组和性别/年龄与之相匹配的正常老人117名组成对照组,应用PCR-RFLP的方法对被研究对象mtDNA上分别位于第4336、5460和8021三个位置的点突变情况进行检测。结果第4336位置上的碱基未发现存在突变的现象。第8021位置上的碱基仅在正常老人组内检测到1例突变型,其余均为野生型。在第5460位置上对照组突变率为2.6%(3/117),AD老人组中突变率为6.3%(7/111),显著性检验χ2=1.902,P=0.168。结论在我国上海汉族人群中线粒体DNA上第4336位置上可能不存在点突变的现象,第8021位置上突变也很少发生,在第5460位置上的碱基可能出现A或T的点突变,但这种突变的发生可能与AD的发生无直接关联。     

散发性Alzheimer''''s病D21S210(GT—12)微卫星体的等位基因频率

在家族性早发Alzheimer's病(FEO—AD)中,位于21号染色体上的淀粉样前体蛋白(Amyloidprecursor Protein,APP)基因迄今已发现四个引致疾病的突变,用命名为GT—12的D21S210多等位 基因卫星体进行的连锁分析已被证明在累及家族性AD(FAD)基因的评定中是有用的工具。这个标记紧密连锁于21q21.1的APP基因。大多数AD病例被认为是散发性的和非家族性的。然而,早期研究提示在散发性病例中也有重要的遗传影响,而基因一环     

家族性早发性Alzheimer病的发病年龄与遗传病因相关

我们和其他研究小组的工作表明,某些早发性AD的病因是淀粉样前体蛋白(APP)基因的突变,有些则与14号染色体相应基因座相关,在12个适合连锁分析的早发性家系中,3个家系(F19,F23,F172)具有APP突变,而剩下的9个家系,除F126之外,8个家系均与14号染色体上位点连锁。方差分析结果表明早发性家族性AD的发病年龄具家族     

变性高效液相色谱法在家族性阿尔茨海默病突变位点检测中的应用

目的 通过对一个阿尔茨海默病（Alzheimer disease,AD)大家系突变位点的检测，探讨中国人家族性AD（familial Alzheimer disease,FAD)的发病机制，同时观察变性高效液相色谱法（denaturing high performance liq-uid chromatography,DHPLC)的实用价值。方法 应用DHPLC方法及DNA直接测序技术。对一个有130人的AD大家系和50名正常对照者进行了淀粉样蛋白前体（amyloid precursor protein,APP)基因，早老素1（prese-nilin1,PS1)基因的突变位点检测。结果 （1）5例AD患者及4例家系中的无痴呆症状者（Ⅳ-30,37,41,43)经DHPLC检测有PS1基因的第5外显子的突变峰，家系中其他成员无突变峰，PS1基因其他外显子检测及APP基因检测，家系中所有成员和正常对照组均无突变峰。（2）上述9例经DNA直接测序在PS1基因第5外显子的136号密码子发生了GCT→GGT错义突变，使丙氨酸变为甘氨酸（Ala136Gly)，无突变峰者DNA测序均未发现异常。结论 （1）DPLC检测显示出这-AD大家系PS1基因第5外显子存在突变，该突变位点可能为中国人FAD患者早老素基因突变点之一。（2）DHPLC技术可作为大样本筛查突变位点的一种便捷可靠手段。     

肾素-血管紧张素系统干预与阿尔茨海默病

阿尔茨海默病(AD)是一种以β淀粉样蛋白异常沉积和tau蛋白异常磷酸化为典型病理学改变的神经退行性疾病,是最常见的痴呆类型。肾素-血管紧张素系统(RAS)为体内重要的心血管调节系统,近来研究证实脑内存在独立的RAS;自从研究发现血管紧张素转换酶(ACE)基因多态性与AD发病相关以来,RAS与AD神经生理学关系得到进一步深入研究,越来越多的研究也进一步证实了RAS影响AD的发病和进展。     

单纤维PCR技术检测线粒体DNA的突变

单纤维PCR技术在单细胞水平研究线粒体DNA(mitochondrialDNA,mtDNA)的突变,不仅能确定线粒体肌病与脑肌病患者骨骼肌是否存在线粒体DNA突变及其类型,还能研究线粒体DNA突变类型和突变比例与骨骼肌病理改变的相互关系,认识线粒体基因型与表型的对应关系。线粒体是细胞的“能     

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.     

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.     

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.     

Neonatal Seizures: Problems in Diagnosis and Classification

Summary: The clinical identification of neonatal seizures is critical for the recognition of brain dysfunction; however, diagnosis is often difficult because of the poorly organized and varied nature of these behaviors. Current classification systems are limited in their ability to communicate motor, autonomic, and electroencephalo-graphic features of seizures precisely and to provide a basis for uniform effective diagnosis, therapy, and determination of prognosis. Recent investigations of neonates, utilizing bedside electroencephalographic/polygraphic/ video monitoring techniques, have provided the basis for improved diagnosis and classification of seizures in the newborn. These studies have demonstrated that not all clinical phenomena currently considered to be seizures require electrocortical epileptiform activity for their initiation or elaboration. In addition, the specific clinical character of the phenomena considered to be seizures, the clinical state of the infant, and the character of the EEG indicate the probable pathophysiological mechanisms involved and suggest probable etiologies, prognosis, and therapy. Similarities between animal models that demonstrate reflex physiology and neonates with motor automatisms and tonic posturing suggest that these clinical behaviors may not be epileptic in origin but, rather, primitive movements of progression and posture mediated by brainstem mechanisms. Although not all clinical behaviors currently considered to be neonatal seizures may have similar pathophysiological mechanisms, they are clinically significant because they all indicate brain dysfunction.     

Valproate Monotherapy in the Management of Generalized and Partial Seizures

Summary: For decades, therapeutic tradition has promoted the concept of polypharmacy in the management of epilepsy. In recent years, however, studies have shown that, for most patients, monotherapy can provide comparable or better seizure control than administration of multiple anticonvulsants, while diminishing the potential for adverse reactions, drug interactions, and poor compliance. Valproate is an important monotherapeutic agent that is highly effective in the control of idiopathic primary and secondarily generalized epilepsies, and partial seizures that do not generalize. Comparative studies have found that valproate is at least as effective as phenytoin and carbamazepine in the treatment of generalized and partial seizures. Given the similar efficacy, other factors such as pharmacokinetics and side effects may therefore determine anticonvulsant selection for monotherapy.     

Un nouveau cadre conceptuel de travail pour la psychiatrie

In an attempt to place psychiatric thinking and the training of future psychiatrists more centrally into the context of modern biology, the author outlines the beginnings of a new intellectual framework for psychiatry that derives from current biological thinking about the relationship of mind to brain. The purpose of this framework is twofold. First, it is designed to emphasize that the professional requirements for future psychiatrists will demand a greater knowledge of the structure and functioning of the brain than is currently available in most training programs. Second, it is designed to illustrate that the unique domain which psychiatry occupies within academic medicine, the analysis of the interaction between social and biological determinants of behavior, can best be studied by also having a full understanding of the biological components of behavior.     

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.