人脑胶质细胞瘤恶性进展相关基因表达谱中DNA修复基因分析

目的探讨DNA修复基因的变化及其在人脑胶质瘤恶性进展过程中的作用.方法采用cDNA芯片检测同一患者初发和两次复发的胶质瘤组织与正常脑组织中基因表达的差异,建立胶质瘤恶性进展相关基因表达谱.根据GeneBank、GeneCards上检索的资料分析其中DNA修复基因的变化.结果确立与DNA修复相关的基因17条,分别在肿瘤恶性进展的不同阶段上调或下调.结论一些DNA修复基因可能参与了人脑胶质瘤的放疗、化疗耐受及恶性进展过程.     

胶质瘤细胞分化与恶性进展相关分子研究

目的 探讨胶质瘤细胞分化与恶性进展的分子变化,为进一步研究胶质瘤发生的分子病因创造条件.方法 在自建的人脑胶质瘤细胞诱导分化和神经节细胞胶质瘤恶性转化相关基因表达谱中,采用生物信息学聚类方法筛选胶质瘤细胞分化与恶性进展密切相关的新基因,进而分别用反向多点杂交和逆转录聚合酶链反应(RT-PCR)技术在分化程度不同的临床胶质瘤标本中加以验证.又将最感兴趣的基因用脂质体法转染胶质瘤细胞,观察其调控分化效应.结果 随胶质瘤细胞诱导分化而表达量增高的基因有ADP核糖转移酶样蛋白3(ADP-ribosyltransfrase like protein3, Adprt3)、NESH蛋白(new molecule containing SH3 domain)、维甲酸和干扰素诱导的细胞凋亡调控蛋白(genes associated with retinoid IFN induced mortality-19, GRIM-19)、半胱胺天冬酶-1(Caspase-1)和erbB-2转导蛋白-1(transducer-1 of erbB-2, TOB1)共5条;表达量下降的有p8蛋白(p8 protein)、Src样结合蛋白(Src-like adoptor protein, SLAP)、过氧化物酶体增殖受体结合蛋白(peroxisome proliferation-activated receptor binding protein, PPARBP)、尤文肉瘤断列点区-1(Ewing sarcoma breakpoint region-1, EWSR-1)、细胞呼吸因子-1(nuclear repiratory factor-1, NRF-1)、单核细胞超化蛋白-1(monocyte chemotactic protein-1, MCP-1)共6条.随神经节细胞胶质瘤恶化表达量增高的有锌指蛋白157(Zinc finger protein 157)、胆碱转运因子-2(CTL2)、T54蛋白(T54 protein)、血清素(albumin)、肌球蛋白轻链(myosin light polypeptide)、血清蛋白P(serum amy loid P component)、肿瘤坏死因子受体调节因子-1(TNF receptor shedding regulator, ARTS-1)、嗜酸细胞源性神经毒素(eosinophil-derived neurotoxin, EDN)和剪切刺激因子(cleavage stimulation factor, CstF)共9条基因,下降的有胆碱激酶样蛋白(choline kinase-like protein)和DNA多聚酶p12亚基(DNA polymerase epsilon p12 subnit)共2条.结论 我们筛选到的与胶质瘤细胞分化或恶性进展密切相关的新基因共22条,尤其是ARTS-1、TOB1等基因可进一步用于基因转染、RNA干扰和基因敲除等作为调控胶质瘤细胞分化的关键基因进行研究.     

Livin基因短发卡RNA表达质粒的构建及其对胶质瘤Livin基因表达的影响

目的构建凋亡抑制基因livin基因的特异性短发卡RNA（siRNA）真核表达载体,并观察其在人脑胶质瘤细胞中对livin基因表达的抑制。方法设计有小发夹结构的2条livinβ siRNA对应的DNA序列,将其克隆入pSliencer 3.1质粒,构建重组质粒pSliencer-livinβ,对重组质粒进行酶切分析和DNA序列测定。以脂质体法将pSliencer-livinβ转染人胶质瘤细胞。采用RT-PCR和Western-blot检测Livinβ蛋白的表达,筛选最有效的一组pSliencer-livinβ质粒。结果酶切及测序证实质粒pSliencer-livinβ构建成功。转染后胶质瘤细胞livinβmRNA和蛋白表达均受到明显抑制。结论成功构建livinβ基因的特异性短发卡RNA（siRNA）真核表达载体能够显著抑制人胶质瘤细胞livinβ基因的表达。     

胶质瘤恶性进展相关基因PASG敲除后基因表达谱的改变

目的探索胶质瘤恶性进展相关PASG基因与胶质瘤发生发展的关系。方法选择性敲除PASG基因7.126kb基因组DNA序列(含该基因第10～12个外显子),并从形态学及全基因组基因表达水平观察基因敲除后的改变。结果PASG基因敲除鼠全基因组表现为低甲基化水平。海马区皮层的大锥体细胞存在细胞形态、排列层次和数量的异常。鼠脑全基因组差异基因表达谱分析显示:PASG基因敲除后,表达差异超过1.6倍的基因共有123条,其中61条表达下调,62条表达上调。结论PASG基因作为上游调控基因,通过改变基因组甲基化水平调控下游一系列细胞增殖分化相关基因表达。PASG基因表达异常导致下游相关基因的表观遗传修饰改变可能是胶质瘤发生发展的早期分子事件,值得进一步深入研究。     

不同恶性程度胶质瘤细胞基因的差异表达

弄清胶质瘤基因表达谱的变化，对深入研究胶质瘤发生、发展的分子机制有重要意义。本实验用基因芯片技术，比较不同恶性程度的人胶质瘤细胞系CHG-5（WHO分级Ⅱ级）和SHG-44（WHO分级Ⅳ级）的差异表达基因，为胶质瘤分子机制的进一步研究提供基础资料，以期改善胶质瘤的诊断和治疗。     

TaqMan低密度表达芯片检测DNA损伤修复基因在原发胶质瘤中的表达研究

目的运用低密度表达谱芯片检测人脑原发胶质瘤组织中DNA损伤修复基因的表达情况,进一步分析其表达变化的意义。方法使用TaqMan低密度表达芯片技术检测27个DNA损伤修复基因在40例不同级别原发胶质瘤组织和10例正常脑组织中的表达情况,并通过统计学分析其在不同级别胶质瘤和正常脑组织中的表达差异。结果与正常脑组织相比较,有13个DNA损伤修复基因在Ⅱ、Ⅲ、Ⅳ级胶质瘤中均表达下调,包括ERCC1、ERCC2、ERCC3、ERCCA、MGMT、MLH1、MLH3、NTHL1、OGG1、RAD50、SMUG1、XRCC4、XRCC5(P<0.05)。MSH2、MSH6、NUDT1和XRCC3只在Ⅱ级和Ⅲ级胶质瘤中表达下凋;MRE11A和MUS81只在Ⅲ级和Ⅳ级胶质瘤中表达下调。PMS2、RAD52和XRCC1只在Ⅲ级胶质瘤中表达下调,而UNG只在Ⅱ级中表达下调。结论TaqMan低密度表达芯片为多个基因的同时定量表达提供了一种准确、快速、有效的多变量检测技术,可用于发现新的肿瘤相关基因。大量的DNA损伤修复基因的表达下调,与胶质瘤的发生密切相关。     

ATRX基因突变在胶质瘤发生和发展中作用的研究进展

α地中海贫血伴智力低下综合征X连锁(ATRX)基因是位于X染色体的α地中海贫血伴智力低下综合征的致病基因,在染色质重塑、基因组和端粒稳定性的维持中起重要作用。约30%的胶质瘤患者存在ATRX基因突变及其编码的ATRX蛋白缺失,是世界卫生组织(WHO)Ⅱ、Ⅲ级星形细胞瘤以及继发性胶质母细胞瘤的特征性分子改变。此外,ATRX基因突变可作为评估胶质瘤患者预后的指标。ATRX缺失的胶质瘤细胞通过端粒替代延长机制维持端粒的长度,其端粒DNA的损伤重,克服端粒DNA的损伤可能是此类胶质瘤快速恶性进展的重要机制,针对端粒DNA的损伤修复进行干预可能达到靶向治疗的效果。     

胶质细胞分化障碍与胶质瘤发生和发展相关分子研究

我们已经在细胞形态学等方面证明,无论在体外还是动物体内诱导分化剂可使分化差的胶质瘤细胞向分化好的方向转化;而在人体内,分化相对好的神经细胞胶质瘤能自发地向分化很差的多行性胶质母细胞瘤恶性转化,但其发生的分子机制不清。为探讨胶质瘤发生和发展的分子变化,进一步研究胶质瘤发生的分子病因创造条件,在自建的人脑胶质瘤细胞诱导分化和神经节细胞胶质瘤恶性转化相关基因表达谱中,采用生物信息学聚类分析方法筛选胶质瘤分化与去分化密切相关的新基因,进而分别用DotBlot和RT-PCR在分化程度不同的临床胶质瘤标本和处于不同分化阶段体…     

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.     

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.     

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.     

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.     

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.     

Special Pharmacokinetic Considerations in Children

Summary: Pediatric patients have greater degrees of pharmacokinetic variability and unpredictability than adults. This variability results from the effects of pharmacogenetics, age and growth, prior and current comedication, and disease. Newborns with seizures have the least predictable dosage requirements, and their needs change as drug-eliminating mechanisms mature in the neonatal period. Infants have the highest relative capacities to eliminate antiepileptics of any age group and require the largest relative doses. In addition to age-related trends, children demonstrate the same drug-specific, pharmacokinetic phenomena that adults do, including nonlinear phenytoin elimination, nonlinear valproate binding, and autoinduction of carbamazepine. Intercurrent illness and drug interactions further modify the age-related pharmacokinetic patterns in children and make dosage requirements even more unpredictable. Recent studies have shown that febrile illness can affect drug elimination, sometimes decreasing drug levels by 50% or more. Intermittent treatment with benzodiazepines administered either orally or rectally can be an important adjunct and help minimize this type of problem for children with marginally controlled epilepsy. Intermittent benzodiazepines are also helpful for children who have febrile seizures and who need only occasional antiepileptic protection.