Par-4反义寡核苷酸对谷氨酸诱导PC12细胞STAT3活性下调的抑制作用

目的研究Par-4反义寡核苷酸拮抗谷氨酸对PC12细胞中信号转导子和激活子3(STAT3)活性的下调作用及其抗凋亡意义.方法脂质体将Par-4反义寡核苷酸转染PC12细胞.谷氨酸诱导PC12细胞凋亡.吖啶橙/溴化乙锭荧光染色观察PC12细胞形态.流式细胞分析评价凋亡百分率.Western blot测定Par-4的蛋白表达量,凝胶迁移改变实验测定STAT3的DNA结合力.结果谷氨酸诱导PC12细胞中蛋白表达上调,Par-4反义寡核苷酸呈剂量依赖性地拮抗其上调(P＜0.01).谷氨酸诱导PCl2细胞中STAT3的DNA结合力下调,Par-4反义寡核苷酸拈抗其下调(P＜0.01).Par-4反义寡核苷酸拮抗谷氨酸诱导的PC12细胞凋亡.如予Jak/STAT3信号通路阻断剂AG-490预处理,则其拮抗作用被下调.结论Par-4反义寡核苷酸拈抗谷氨酸诱导的PC12细胞凋亡,其机制可能与STAT3活化有关.     

磷酸化蛋白酪氨酸激酶及信号转导子和转录激活子在谷氨酸诱导的PC12细胞凋亡中的表达研究

目的探讨谷氨酸诱导PC12细胞凋亡后磷酸化蛋白酪氨酸激酶2（P-JAK2）、磷酸化信号转导子与转录激活子3（P-STAT3）表达的变化及意义。方法采用谷氨酸诱导PC12细胞发生凋亡，实验分为6组，分别为正常对照组、500μmol／L谷氨酸作用5、10、20、30、60min组，应用流式细胞仪观察PC12细胞凋亡．Western blot定量观测PC12细胞P-JAK2与P-STAT3蛋白表达的变化。结果对照组PC12细胞的凋亡率为（2．71±0．32）％；经500μmol／L谷氨酸作用PC12细胞20min，凋亡率增加到（61．20±4．60）％，与对照组相比差异有显著性意义（P=0．000）；Westem blot检测结果表明P-JAK 25 min在胞浆中开始表达，20min达最高峰，是5min组（3．52±0．20）倍（P=0．002）；P-STAT35min表达增强，30min达高峰，为5min组的（4．76±0．17）倍（P=0．000）。结论细胞损伤激活了JAK／STAT信号转导通路，该通路参与了神经细胞凋亡的过程。     

嘌呤霉素敏感的氨肽酶对β-淀粉样蛋白诱导的细胞凋亡的影响

目的 探讨嘌呤霉素敏感的氨肽酶(PSA)对β-淀粉样蛋白(Aβ25-35)诱导的SH-SY5Y细胞、PC12细胞凋亡的影响. 方法 采用MTT法检测Aβ25-35对SH-SY5Y、PC12细胞生长的影响;Hoechst染色检测Aβ25-35对SH-SY5Y、PC12细胞核形态的影响;进一步采用脂质体转染法在SH-SY5Y细胞中瞬时转染PSA-siRNA,在PC12细胞中瞬时转染PSA重组质粒,加入Aβ25-35作用24h后收集细胞,进行流式细胞术检测细胞凋亡率;Western blotting检测PSA、caspase-3蛋白的表达变化;酶标仪检测caspase-3活性. 结果 Aβ25-35抑制SH-SY5Y、PC12细胞增殖,细胞核发生凋亡的形态学改变,流式检测细胞凋亡率增加;在SH-SY5Y细胞中,沉默PSA表达能使Aβ25-35诱导的细胞凋亡率升高,促进caspase-3酶原激活,caspase-3活性升高.反之,PC12细胞中过表达的PSA能使Aβ25-35诱导的细胞凋亡率下降,抑制caspase-3酶原激活,caspase-3活性降低. 结论 Aβ25-35能抑制神经细胞生长,引起神经细胞凋亡;PSA能抑制Aβ25-35诱导的神经细胞凋亡,对神经元具有保护作用,其机制可能与抑制caspase-3通路的激活有关.     

兔视神经损伤后谷氨酸对视网膜的兴奋毒性损伤作用研究

目的探讨家兔视神经损伤后谷氨酸浓度变化对视网膜的兴奋毒性及其作用机制。方法 40只健康雄性日本大耳白家兔随机分成2组,A组35只,B组5只。A组家兔左眼为实验制备视神经损伤模型,右眼为对照眼。B组家兔双眼同时制备视神经损伤模型。分别于第1、3、7、14及28d随机处死A组7只家兔及B组1只家兔,检测家兔实验眼和对照眼视网膜谷氨酸浓度,并观察B组家兔视网膜病理形态学改变。结果家兔视神经损伤后视网膜内谷氨酸浓度逐渐升高,3d达到高峰,14d时家兔实验眼视网膜谷氨酸浓度仍高于对照眼(p<0.05),28d时其视网膜谷氨酸浓度无统计学差异(p>0.05)。家兔视网膜病理形态学观察:视神经损伤后1d,神经节细胞排列紊乱;3～7d,视网膜节细胞大量空泡化;7d～14d,视网膜厚度变薄,神经节细胞减少;14d后视网膜各层细胞改变逐步趋于稳定。结论家兔视神经损伤后,视网膜谷氨酸浓度升高是视网膜神经节细胞继发损伤的原因之一。     

氯通道在一氧化氮诱导离体大鼠海马神经元凋亡中的作用

目的 观察氯通道阻断剂SITS和DIDS对NO诱导的大鼠离体海马神经元凋亡的效应,探讨氯通道在缺血性脑损伤中的作用。方法 离体培养12天的SD大鼠海马神经元,随机分为正常对照组、NO处理组、NO处理后使用氯通道阻断剂组,对各组神经元分别在相应的时间点进行Hoechst荧光染色观察凋亡细胞数和MTT实验定量检测神经元的存活率,western blot 分析凋亡信号分子caspase-3的变化。结果 SITS和DIDS呈剂量依赖性地抑制NO诱导的神经元损伤,并能抑制损伤所引起的caspase-3的激活,提高神经元的存活率。结论 氯通道阻断剂对NO诱导的大鼠海马神经元凋亡有一定的保护作用。     

转化生长因子-β1与脑缺血关系的研究进展

脑缺血是以脑循环血流量减少为特征的中枢神经系统疾病,具有发病率高、致残率高和死亡率高的特点,其发病机制目前尚未完全明确,近年来认为炎症在其发生发展中起到重要作用[1].转化生长因子-β1(TGF-β1)是一种多功能细胞因子,可通过其受体和特定信号转导通路对机体多种细胞的生长、分化、迁移、凋亡及细胞外基质生成等发挥生物学功能[2].目前发现,TGF-β1可通过多种途径参与脑缺血后损伤与修复的病理生理过程.本文就TGF-β1的生物学特性及其在脑缺血中的作用和潜在作用机制等进行综述.     

氯化锂-匹罗卡品致痫大鼠海马结构中CLC-2、CLC-3氯通道表达变化的研究

目的 研究ClC-2、ClC-3氯通道在氯化锂-匹罗卡品大鼠慢性癫痫模型中分布和表达的变化,探讨其在癫痫发作病理机制中的作用.方法 Wistar大鼠采用随机数字表法分成致痫组(60只)与对照组(20只),其中致痫组根据处死及处理时间又分为24h组、14d组与30d组,每组20只.致痫组复制氯化锂-匹罗卡品大鼠慢性癫痫模型,在发作后24h、14d、30d时,分别予以:(1)免疫组化染色,观察ClC-2、ClC-3氯通道蛋白在海马表达的分布情况及其致病后不同时点的吸光度(A)值的变化;(2)RT-PCR,观察ClC-2、ClC-3氯通道mRNA在致痫后不同时点的变化.结果 (1)与对照组比较,致痫后14d至30d,致痫组免疫反应阳性神经元数和A值明显减少和降低,差异有统计学意义(P<0.05);ClC-2 mRNA表达降低,差异有统计学意义(P<0.05).(2)与对照组比较,致痫组致痫后24 h,海马CA1、CA3及齿状回各层ClC-3免疫反应阳性神经元数和A值明显增加和升高,差异有统计学意义(P<0.05);ClC-3氯通道mRNA表达明显增加,差异有统计学意义(P<0.05).结论 癫痫慢性期的发作和ClC-2氯通道的减少有关.     

Aβ1-40诱导的神经干细胞凋亡中钾通道和JNK信号转导通路的作用

目的探讨Aβ1-40诱导的神经干细胞凋亡中钾通道与JNK的作用,以及钾通道与JNK的关系,进一步了解AD的发病机制。方法应用MTT法、Hoechst33342法、比色法及Westernb1ot法分别检测以TEA和SP 600125作用的Aβ1-40诱导神经干细胞的存活率、凋亡发生率、Caspase-3活性的改变及JNK磷酸化的情况。结果预先加入TEA使Aβ1-40诱导的神经干细胞的存活率增加,凋亡减少;JNK的选择性阻断剂SP 600125可显著的保护Aβ1-40诱导的神经干细胞的凋亡。在Aβ1-40孵育前30min加入TEA,与Aβ1-40共同孵育24h,TEA使JNK的磷酸化表达显著降低。结论 Aβ1-40可以使神经干细胞发生凋亡。钾通道在Aβ1-40诱导的神经干细胞凋亡时被激活,TEA可以明显减轻Aβ1-40诱导的神经干细胞的凋亡。Aβ1-40诱导神经干细胞后JNK信号转导通路参与了凋亡的发生,SP600 125对Aβ1-40诱导的神经干细胞具有明显的保护作用。TEA作用于Aβ1-40诱导的神经干细胞可以使JNK蛋白表达下降,说明Aβ1-40引起的钾通道激活和JNK磷酸化两者之间有一定的相互联系,进而诱发了下游凋亡相关蛋白的改变。     

神经肽Y通过Y1受体激活P13K通路促进RAW264．7细胞中TGF-β1的产生

目的探讨神经肽Y对巨噬细胞系RAW264．7分泌转化生长因子TGF—β1的影响。方法酶联免疫吸附实验检测细胞培养上清液中的TGF-β1水平;细胞计数试剂盒CCK-8检测细胞活力;Western blot检测磷脂酰肌醇3激酶P13K p85的磷酸化水平。结果神经肽Y主要通过激活其Y1受体信号通路增加RAW264．7细胞中TGF—β1的产生,并可在10min内快速激活P13K通路。P13K通路阻滞剂可消除NPY对TGF-β1产生的促进作用。结论神经肽Y能够通过Y1受体促进RAW264．7细胞的TGF-β1的表达,此作用可能由P13K介导。     

PI3K/Akt信号转导通路与神经细胞凋亡研究进展

<正>脑缺血再灌注损伤中最常出现的是细胞凋亡,细胞凋亡的机制复杂多样,在众多细胞凋亡机制涉及的信号转导通路中,PI3K/Akt信号转导通路是最为重要的,其发挥抑制细胞凋亡作用的机制可通过调控凋亡蛋白和凋亡基因来实现,也可以影响线粒体、内质网等发生相应变化实现。神经营养因子激活了PI3K/Akt信号转导通路,但是它作为大分子,通过血脑屏障很难,探究一种既能够穿透血脑屏障又能够将PI3K/Akt信号转导通路高效激活的药物迫在眉睫。     

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.