帕金森炎症细胞模型的建立与炎症机制的研究

目的观察脂多糖（LPS）对小鼠中脑原代多巴胺能神经元的损伤作用。方法取孕13d的C57/BL小鼠胚胎中脑原代培养,以LPS为工具药激活小胶质细胞,通过酪氨酸羟化酶（TH）免疫细胞荧光染色,计数TH阳性细胞数目并观察形态的变化,ELASA法观察炎症因子的变化。结果 不同浓度LPS（0.1、1.0和10.0mg/L）处理72h与相同浓度LPS（1mg/L）不同时间点（8h、24h、72h）分别处理原代混合细胞多巴胺神经元,TH阳性细胞减少,大部分细胞表现为突起数目的减少,突起变短并有串珠样改变。分泌细胞因子TNF-α含量与给药组相比显著增多（P〈0.001）。结论 LPS通过激活小胶质细胞释放TNF-α发挥对多巴胺能神经元的损伤作用。     

β-arrestin 2对多巴胺能神经元的保护作用及机制研究

目的探讨β-arrestin 2对多巴胺能神经元的保护作用及机制。方法分离并培养原代小鼠中脑小胶质细胞,脂多糖(LPS)处理后采用实时定量PCR检测炎性细胞因子IL-6、IL-1β和TNF-α的转录水平,ELISA检测上述因子的表达水平;将原代小鼠中脑小胶质细胞和多巴胺能神经元Transwell共培养(细胞数2∶1),LPS处理后TUNEL法检测多巴胺能神经元凋亡,酪氨酸羟化酶(TH)免疫组织化学法检测多巴胺能神经元。结果原代小胶质细胞经LPS处理后IL-6、IL-1β和TNF-α的转录水平及表达水平均较对照组显著升高,而β-arrestin 2高表达能抑制这种炎症反应;β-arrestin 2高表达能显著抑制LPS处理所致的多巴胺能神经元凋亡,抑制多巴胺能神经元数目的减少。结论β-arrestin 2可能通过抑制小胶质细胞炎性细胞因子的产生,从而对多巴胺能神经元发挥神经保护作用。     

Aβ25-35激活小胶质细胞机制的研究

目的以Aβ25-35为工具药，观察小胶质细胞激活后形态和功能的变化，以探讨阿尔茨海默病发病过程中活化的小胶质细胞对神经元损伤作用的可能机制。方法用Aβ25-35处理体外培养的大鼠小胶质细胞，采用倒置相差显微镜观察细胞形态，RT-PCR方法检测炎性因子肿瘤坏死因子（TNF）-α、白介素（IL）-1β、诱导型一氧化氮合酶（iNOS）mRNA表达，Griess反应检测一氧化氮（NO）生成量，超氧化物岐化酶可抑制的WST-1还原法检测细胞外超氧化物产生量。结果Aβ25-35作用后，小胶质细胞形态发生明显变化，细胞胞体延长，由胞体伸出一个或多个树枝状突起，变为类巨噬样细胞；细胞外超氧化物产生量明显增加；但TNF—α、IL-1β、iNOS mRNA表达及NO释放量无明显改变。结论Aβ25-35激活小胶质细胞以活性氧类物质产生为主，活性氧类物质在介导Aβ诱导的神经毒性中起了关键作用。     

神经胶质细胞在帕金森病发病机制中的作用

目的　探讨胶质细胞在帕金森病 ( Parkinson's disease,PD)发病机制中的作用。方法　采用立体定向术将神经毒素 6 -羟基多巴 ( 6 - hydroxydopamine,6 - OHDA)注入大鼠右侧纹状体内 ,制备经典的帕金森病动物模型。观察黑质致密带内多巴胺 ( dopamine,DA)能神经元缺失、胶质细胞的增生和肿瘤坏死因子 ( tumor necrosis factor-alpha,TNF- α)表达水平。结果　模型组右侧黑质 DA能神经元的数量明显减少 ,同时伴有星形胶质细胞和小胶质细胞的数量明显增高 ( P<0 .0 5 ) ,TNF- α在模型组右侧黑质和纹状体内有阳性表达 ,且主要分布在激活的小胶质细胞上。结论　神经胶质细胞可能是通过 TNF- α等细胞因子 ,导致或参与 DA能神经元的大量的变性、死亡。以抑制小胶质细胞的激活作为靶点的药物研究有可能为 PD的治疗提供新的思路。     

脂多糖预处理改善脂多糖诱导的中脑脑片神经元损伤

目的探讨脂多糖（lipopolysaccharide,LPS）预处理对脂多糖所致中脑脑片多巴胺能神经元炎性损伤的影响及其可能的机制。方法建立大鼠中脑脑片体外培养体系,于体外培养14d后以不同剂量脂多糖（0、1、3、6及10ng／mL）预处理24h,然后用大剂量脂多糖（100ng／mL）作用72h,观察脂多糖预处理对脑片乳酸脱氢酶（lactic acid dehydrogenase,LDH）活性的影响。通过免疫组化检测酪氨酸羟化酶（Tyrosine hydroxylase,TH）和OX-42的阳性细胞数变化,应用酶联免疫吸附法测定培养液上清肿瘤坏死因子-α（tumor necrosis factor-α,TNF-α）水平。结果100ng／mL多糖作用72h后引起脑片TH阳性细胞数从对照组的191&#177;12减少到46&#177;4,LDH活性明显升高（P〈0．01）,小胶质细胞大量激活,TNF-α水平显著增高（P〈0．01）。脂多糖预处理能减少神经细胞的丢失（3ng／mL和6ng／mL的LPS处理后TH阳性细胞数分别为126&#177;12和180&#177;13）,降低脑片LDH活性（P〈0．05）,并有效地抑制小胶质细胞的激活,明显减少TNF-α的生成（P〈0．05）。结论小剂量脂多糖预处理可改善脂多糖对大鼠中脑脑片多巴胺能神经元的损伤,其作用机制可能是通过抑制小胶质细胞的激活,减少TNF-α的释放,减轻炎症反应对神经元的损伤。这种保护作用可为帕金森氏病的治疗提供新思路。     

肿瘤坏死因子-α与急性脑血管病

中枢神经系统多种细胞可释放TNF—α等炎性细胞因子,如神经元细胞,血管内皮细胞,小胶质细胞,星形细胞,成纤维细胞,巨噬细胞及平滑肌细胞。急性脑血管病后TNF-α释放迅速增加。TNF—α作为细胞间相互作用的炎性细胞因子,与细胞膜上TNP—α受体结合后发挥多种生物学效应,直接或间接地导致脑血管内皮细胞的损伤,激活磷脂酶A_2和肾上腺素能β受体,使血脑屏障通透性增高,出现血管     

凝血酶诱导的小胶质细胞激活促进多巴胺能神经元变性

目的探讨凝血酶（Thrombin）诱导小胶质细胞（Micoglia）激活与黑质多巴胺能神经元变性的关系。方法采用立体定向术注射凝血酶至大鼠黑质,在不同时间点观察酪氨酸羟化酶（tyrosine hydroxylase,TH）神经元的表达及小胶质细胞的激活情况;同时检测黑质NO量及iNOS mRNA表达。结果（1）凝血酶注入大鼠黑质导致明显的黑质多巴胺能神经元变性,呈时间依赖性,TH阳性细胞数在第3d开始下降,第7d有大量的TH阳性细胞丢失,与对照侧相比下降达约53％（P〈0．01）;高倍镜下可见胞体皱缩、突起明显缩短或减少;14d时细胞数下降至21％,30d时下降至12％（P〈0．01）。（2）凝血酶注射入黑质4h后小胶质细胞开始呈现为“灌木丛样”或少量呈现“阿米巴样”：12h后小胶质细胞数目明显增加且绝大部分呈现“阿米巴样”;24h后细胞已完全激活,“阿米巴样”细胞达高峰;3d维持高峰;14d后小胶质细胞染色变淡,体积变小,“阿米巴样”细胞数目下降。（3）与对照组相比,iNOSmRNA表达明显上调及NO合成增加（P〈0．05）,并且有iNOS在小胶质细胞表达。结论凝血酶对多巴胺能神经元具有一定的损毁作用,小胶质细胞的激活先于多巴胺能神经元变性,其激活后释放的NO有可能参与多巴胺能神经元变性。     

脂多糖与帕金森病模型的研究

中脑黑质多巴胺能神经元变性是帕金森病的主要病理变化,炎症反应和氧化应激与神经元变性有密切的联系。体内外实验应用脂多糖可诱发小胶质细胞激活,使之释放大量的各种细胞毒性因子(包括NO等自由基),触发炎症反应和氧化应激,选择性使中脑多巴胺能神经元变性死亡,降低酪氨酸羟化酶的活性,使多巴胺水平下降,最终致帕金森病样病理改变。在脂多糖所致的一系列病理变化中,干预小胶质细胞激活及细胞毒性因子的释放,有助于阻止帕金森病的进展。     

调节性T细胞缓解帕金森病中多巴胺神经元炎性损伤

免疫炎症可能是引起帕金森病病理机制级联反应最终导致多巴胺神经元变性缺失的主要因素,黑质纹状体多巴胺神经元变性与小胶质细胞激活和T淋巴细胞浸润相关。调节性T细胞可调控小胶质细胞的激活反应,缓解Th17细胞介导的神经炎症。因此,针对调节性T细胞在其天然免疫和适应性免疫中的相互作用,通过硝基化α-突触核蛋白疫苗、格拉默醋酸盐和骨髓间充质干细胞等方法调控调节性T细胞的数量和功能,清除积聚的错误折叠蛋白,可为帕金森病神经保护治疗提供新的策略。     

小胶质细胞活化在实验性自身免疫性脑脊髓炎中的作用机制

目的探讨小胶质细胞活化在实验性自身免疫性脑脊髓炎(EAE)发病机制中的作用。方法利用同种脑脊髓匀浆诱导EAE模型。采用免疫组化法、免疫组织荧光染色观察小胶质细胞对EAE不同病期炎性脱髓鞘病灶的反应,采用免疫组化法、ELISA法观察脑组织及外周血肿瘤坏死因子α(TNF-α)的表达。结果EAE发病前小胶质细胞即开始激活并持续至高峰期,形态学上表现为从正常的细小分枝状逐渐演变为高度分枝状、阿米巴状。免疫组化染色显示TNF-α阳性细胞多为小胶质细胞。EAE大鼠发病前脑组织中小胶质细胞、TNF-α阳性细胞数及外周血TNF-α水平已升高并持续至高峰期。结论小胶质细胞活化伴随EAE发病的整个过程。活化后的小胶质细胞可能通过合成和释放多种炎症介导物及细胞因子如TNF-α,进一步扩大炎症反应,进而促使髓鞘病变。     

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.