少突胶质细胞祖细胞在神经退行性疾病发病机制中的作用研究进展

少突胶质细胞祖细胞(OPCs)分布于整个中枢神经系统, 可增殖、迁移、分化为少突胶质细胞(OLs)。OLs的核心功能是产生髓磷脂, 形成髓鞘包裹轴突, 提高神经传导速率。近年来研究显示, 在多发性硬化、阿尔茨海默病等神经退行性疾病的病灶处存在大量OPCs, 其在中枢神经系统损伤修复过程中具有重要作用, 髓鞘再生受阻的主要原因就是OPCs未能分化为成熟的OLs或者形成的OLs无法发挥正常功能。笔者现围绕OPCs的生理功能及其在多发性硬化、阿尔茨海默病等神经退行性疾病发病机制中的作用进行综述, 以期为神经退行性疾病的研究和治疗提供新的思路及方向。     

小胶质细胞在癫痫中作用的研究进展

正癫痫是神经元突发、异常、过度、同步放电引发的一种发作性脑功能障碍。癫痫发病机制十分复杂。研究发现神经炎症、氧化应激、免疫失调、神经元凋亡、自噬等因素,在癫痫发病过程中发挥重要作用。小胶质细胞是中枢神经系统的免疫效应细胞,参与将神经炎症、氧化应激、神经元凋亡、免疫调节等。本文就小胶质细胞在癫痫中的作用进行综述。1小胶质细胞的概述1.1小胶质细胞的类型与功能小胶质细胞外形和蛋白表达存在差异,不同条件激活的类型和功能状态也有差异[1]。小胶质细胞处于静息状态时体积较小,呈梭状,有树枝状分支;激活后,细胞体积变大,     

NF155及其在脑白质损伤疾病中的研究

在中枢神经系统（central nervous system,CNS）,髓鞘由少突胶质细胞（oligodendrocyte,OL）形成,神经元轴突髓鞘化完成预示着神经发育成熟。髓鞘具有重要的生理功能,它不仅能对神经元轴突起保护作用,而且使轴突绝缘,以确保神经冲动通过跳跃式传导而高速传递。然而在脑白质损伤中,由于神经细胞脱髓鞘,髓鞘生理功能部分或完全丧失,导致一系列病理生理改变。脑白质损伤引起的神经纤维脱髓鞘包括了原发性脱髓鞘和继发性脱髓鞘。     

NgR1复合物的实验研究进展与干扰策略

成年哺乳动物周围神经系统损伤后可有效再生,但中枢神经系统损伤后却很难再生。在分子途径促进损伤中枢神经系统轴突再生的研究中,发现了3种髓磷脂相关抑制性蛋白：Nogo、髓鞘相关糖蛋白（myelinassociatedglycoprotein,MAG）、少突胶质细胞髓鞘糖蛋白（oligodendroeytemyelinglycoprotein,OMgp）在中枢神经系统损伤后发挥着抑制轴突生长的作用,并发现Nogo—A、MAG、OMgp存在于中枢白质的髓鞘内外环和少突胶质细胞的表面,通过与共同受体NgR1特异性结合诱导生长锥塌陷并抑制轴突生长。进而提出了通过阻断NgR1复合物及其下游的信号转导途径来促进神经元轴突再生的设想。本文拟对近年来关于NgR1复合物的研究加以综述。     

p38MAPK在MS/EAE少突胶质细胞系中的作用

<正>多发性硬化(multiple sclerosis,MS)是一种中枢神经系统脱髓鞘性疾病,近年的研究已经证实遗传、环境、免疫等因素改变引起的免疫细胞比例失衡、机体的氧化应激等在MS发病中起到重要作用。髓鞘是有髓神经纤维外包绕的一层膜,它在中枢神经系统主要是由少突胶质细胞的片状突起包绕神经元轴突而形成的螺旋形多长膜性结构。病理染色及免疫组化染色可发现多发性硬化患者的病灶处大量的神经纤维脱髓鞘。     

Peroxiredoxin触发脑缺血后炎性反应的机制

脑梗死是由大脑动脉狭窄或闭塞引起的大脑供血不足所致的脑组织坏死.脑缺血会引起氧、糖以及其他营养成分的缺乏,以至于不能够维持由胶质细胞、内皮细胞、神经元细胞组成的神经元微环境的功能正常.脑缺血性卒中(136.64/10万)已超过恶性肿瘤(135.88/10万)成为中国的第一致死病因.卒中也是单病种致残率最高的疾病[1].脑缺血后的炎性反应是缺血性脑损伤的重要环节,并且与患者的预后相关[2].更多关于脑缺血后炎症反应进展的研究可以为缺血性卒中找到更有效的治疗方法[3].     

局限性脑皮质发育不良的MRI表现

局限性脑皮质发育不良(FCD)的特征是局部脑皮层的神经元与胶质细胞排列异常,有不同程度的脑白质内灰质异位、髓鞘化神经纤维减少及反应性胶质增生。FCD占癫痫手术切除标本病理检查异常的5％～15％,但裸眼以及触诊均不能发现本病。本文研究磁共振(MRI)检查对于FCD的显示能力及其与切除标本的病理学检查之间的联系。     

雪旺细胞与实验性脊髓损伤修复

脊髓损伤是神经科学领域致死率、致残率最高的创伤之一,可直接导致神经元坏死、神经轴突中断,脊髓结构严重破坏.而损伤后的微环境又有诸多不利于脊髓神经轴突再生的因素,如:多种神经营养因子的缺乏以及胶质疤痕和多种抑制再生的物质存在等.雪旺细胞是外周神经系统特有的胶质细胞,包绕轴突形成髓鞘,近年发现雪旺细胞不只在轴突周围形成髓鞘,它还有许多有利于调节损伤后轴突再生的独特功能.大量的动物实验已证明雪旺细胞移植和其他方法的联合应用能够克服这些因素达到促进轴突再生、髓鞘形成及功能恢复的目的,为脊髓损伤治疗带来了新的希望.     

小胶质细胞在癫痫发作状态中的研究进展

癫痫是一组由于脑部神经元异常过度放电引起的中枢神经系统疾病。小胶质细胞作为中枢神经系统的主要免疫细胞对神经的发育和维持起着重要作用。尽管研究报道,小胶质细胞可通过增加炎症介质等生物活性物质介导癫痫发作,但对于炎症介质相关的信号转导通路仍缺乏全面了解。此外,越来越多的证据证明,小胶质细胞在神经元变性、神经发生及突触修剪中发挥着至关重要的作用,这与癫痫的发生发展有关。因此,进一步研究小胶质细胞在癫痫发作过程中的生物学功能,明确小胶质细胞在癫痫中的分子机制,可为临床治疗癫痫提供新的分子靶点。 [国际神经病学神经外科学杂志, 2023, 50(6): 57-62]     

存活素及其对脑缺血后脑损害的保护作用及促血管再生作用

存活素是1997年Ambrosini等[1 ]利用效应细胞蛋白酶受体-1 (EPR-1)的cDNA,从人类基因组文库中筛选克隆出的一个新基因,是抗凋亡蛋白(IAP)家族中的一员.其组织分布具有明显的细胞选择性,表达于胚胎和发育的胎儿组织及绝大多数恶性肿瘤组织中,在终末分化的成人组织中未见表达(除胸腺、生殖腺外),因而存活素在肿瘤的研究中成为热点.然而,最近有研究[2]发现,大脑脉络丛室管膜细胞、神经元、星形胶质细胞和少突胶质细胞中也有存活素的表达,在脑缺血后参与抑制神经细胞凋亡和促进血管新生.现对存活素的分子结构与生物学功能,以及其在缺血性脑血管疾病中的作用作一综述.     

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.