大鼠脑出血后水通道蛋白4的表达与血脑屏障超微结构变化的相关性研究

目的观察脑出血后水通道蛋白4(AQP4)和血脑屏障(BBB)超微结构在脑水肿形成中的不同时间点的变化特征,探讨二者在脑水肿形成中的作用机制。方法采用自体非抗凝血注入尾状核制做脑出血模型,免疫组化法检测脑出血后血肿周围组织AQP4的表达,伊文思蓝检测BBB的通透性,干湿重法检测脑水肿含水量,电镜观察BBB超微结构的变化。结果与对照组相比较,脑出血组在脑出血后6h脑含水量、AQP4表达和伊文思蓝含量开始增加,差异有显著性(P<0.05),72h达到最高峰(P<0.05),之后开始下降,到第7天仍高于正常。AQP4表达与BBB通透性呈显著正相关(r=0.726,P<0.05);AQP4表达与脑含水量的变化规律也趋于一致(r=0.793,P<0.05)。BBB电镜观察:脑出血后6h脑微血管内皮细胞吞饮小泡增多、线粒体堆积。72h胶质细胞足突内线粒体逐渐肿胀、模糊,细胞充满大量空泡,基膜断裂。7d内皮细胞回缩,毛细血管基底膜形态开始恢复。结论脑出血后AQP4表达和BBB的通透性有显著相关性,提示脑出血后可能通过提高AQP4的表达水平,增加BBB的通透性,参与脑水肿的形成。     

溶血磷脂酸对血脑屏障及AQP4蛋白表达的影响

目的 研究溶血磷脂酸对大鼠血脑屏障通透性及水孔蛋白-4(aqaporin-4,AQP4)表达的影响.方法 在立体定向仪下向大鼠右侧尾壳核注射50uL溶血磷脂酸,在不同时间点对注射部位邻近脑组织AQP4蛋白进行免疫组化检测;用伊文斯蓝(Evans blue, EB)作为示踪剂定量测定不同时间点血脑屏障(Blood-brain barrier,BBB)通透性.结果 注射溶血磷脂酸后6 h尾壳核AQP4蛋白表达开始增高,在第2 d达到高峰,并维持到第3 d,以后逐渐下降. 表达增高的部位主要为微血管内皮细胞及其周围的胶质细胞.与对照组各时间点相比,均有显著性差异;LPA注射后6 h同侧尾壳核区BBB对EB通透性开始增加,24 h达最大,到48 h逐渐减低,与对照组相同时间点比差异有显著性(p<0.05).结论 溶血磷脂酸可以促进脑微血管内皮细胞及其周围胶质细胞AQP4蛋白表达的增加,引起血脑屏障通透性的增加,参与脑水肿的发生.     

尼膜同对大鼠脑出血后血脑屏障通透性及水通道蛋白4mRNA表达的影响

目的研究大鼠脑出血后血脑屏障(BBB)通透性与水通道蛋白4(AQP 4)的关系及尼膜同的干预作用。方法采用自体动脉血注入尾状核法制成大鼠脑出血模型,RT-PCR法观察AQP 4 mRNA的表达,伊文思兰法测量BBB通透性,干湿重法计算脑含水量表示脑水肿。结果与对照组相比,脑出血组及尼膜同组BBB通透性均在出血后6h开始升高(0.5955±0.0956、0.5092±0.0309),1d~3d最高(0.8889±0.0968、0.7826±0.0339和0.7914±0.0520、0.7442±0.0753),尼膜同组低于脑出血组(P<0.05);两组AQP 4 mRNA表达也于6h即开始升高(1.06±0.12、0.90±0.15),3d时达到高峰(1.34±0.14对1.27±0.14),尼膜同组低于脑出血组(P<0.05);BBB通透性与AQP 4 mRNA表达呈显著正相关(r=0.686,P<0.01),与脑水肿变化趋势一致。结论脑出血后可能通过上调APQ 4 mRNA表达,增加BBB通透性,参与脑水肿形成;尼膜同可抑制此过程。     

尼膜同对大鼠脑出血后血脑屏障通透性及水通道蛋白4mRNA表达的影响

目的研究大鼠脑出血后血脑屏障(BBB)通透性与水通道蛋白4(AQP4)的关系及尼膜同的干预作用。方法采用自体动脉血注入尾状核法制成大鼠脑出血模型,RT-PCR法观察AQP4mRNA的表达,伊文思兰法测量BBB通透性,干湿重法计算脑含水量表示脑水肿。结果与对照组相比,脑出血组及尼膜同组BBB通透性均在出血后6h开始升高(0.5955±0.0956、0.5092±0.0309),1d~3d最高(0.8889±0.0968、0.7826±0.0339和0.7914±0.0520、0.7442±0.0753),尼膜同组低于脑出血组(P<0.05);两组AQP4mRNA表达也于6h即开始升高(1.06±0.12、0.90±0.15),3d时达到高峰(1.34±0.14对1.27±0.14),尼膜同组低于脑出血组(P<0.05);BBB通透性与AQP4mRNA表达呈显著正相关(r=0.686,P<0.01),与脑水肿变化趋势一致。结论脑出血后可能通过上调APQ4mRNA表达,增加BBB通透性,参与脑水肿形成,尼膜同可抑制此过程。     

精氨酸加压素对星形胶质细胞水孔蛋白-4表达的调节及脑水肿形成影响的研究

目的研究精氨酸加压素(AVP)对星形胶质细胞水孔蛋白-4(AQP4)表达的调节,以及p38 MAPK信号通路在AQP4表达过程的作用,明确AVP及AQP4在脑水肿发生过程中的作用。方法大鼠大脑皮质分离星形胶质细胞,星形胶质细胞经分别用AVP、V1a受体(V1aR)拮抗剂和SB 203580进行处理,采用免疫组织化学技术及RT-PCR对AQP4 mRNA进行检测,Western blot检测p38 MAPK信号通路在AVP诱导AQP4表达中的活化程度。结果500nmol/L的AVP处理6h后,AQP4 mRNA表达开始升高(P<0.01),到12h达高峰(P<0.01),24h后仍维持在较高的水平(P<0.05)。加入p38 MAPK抑制剂SB 203580干预后,AQP4 mRNA表达水平与对照组比较差异不显著(P>0.05);AVP处理15min后p38 MAPK磷酸化水平开始增加,30min达高峰,持续到60min开始下降。V1aR拮抗剂处理后p38 MAPK磷酸化水平整个时间段均未出现明显变化。结论AVP通过激活V1aR引起p38MAPK信号通路活化从而诱导AQP4 mRNA高表达,从基因水平对AQP4进行调节,可能在脑水肿发生中,尤其是在星形胶质细胞水肿形成中起重要作用。V1aR拮抗剂及p38 MAPK抑制剂能抑制AQP4 mRNA的表达,避免星形胶质细胞肿胀。     

尼莫地平对大鼠脑出血周边组织AQP4表达的影响

目的 观察尼莫地平对ICH周边组织AQP4表达、细胞内Ca2+浓度变化及对BBB保护作用的影响.方法 参考Rosenberg等方法复制大鼠ICH动物模型,随机将120只Wistar大鼠分为假手术组(n=20)、脑出血组(n=50)和尼莫地平治疗组(n=50),脑出血后分别观察6h、1d、3d、5d、7d等5个时间点.用免疫组化法测定ICH周边组织AQP4的表达,用荧光标记检测胞内Ca2+及EB作为示踪剂监测BBB的损伤程度,用干湿法测定脑组织含水量.结果 (1)脑出血组3d含水量达到高峰,第7天明显下降,但仍高于正常水平;尼莫地平组3d含水量达高峰,但低于脑出血组;(2)脑出血后6h血肿周边组织EB含量增加,1d达高峰,7d已明显下降;尼莫地平干预后各时间点EB含量明显低于脑出血组,高于假手术组,7d后EB含量恢复正常;(3)脑出血后6h血肿周边组织AQP4表达及细胞内Ca2+浓度逐渐增高,3d达高峰,7d后下降明显;尼莫地平组血肿周边组织AQP4表达及细胞内Ca2+浓度逐渐增高,3d达高峰,明显低于脑出血组.结论 (1)Ca2+能促进AQP4的过度表达,使BBB通透性增加,参与出血性脑水肿的病理过程;(2)尼莫地平可阻断Ca2+向细胞内过度内流,进而降低AQP4的表达,减轻脑水肿程度,为脑出血治疗提供新的靶点.     

Mg对单纯疱疹病毒性脑炎小鼠水孔蛋白-4表达的影响及血脑屏障通透性的研究

目的 研究镁剂对单纯疱疹病毒性脑炎(Herpes simplex encephalitis,HSE)后水孔蛋白-4(aquaporin-4,AQP4)表达、血脑屏障(BBB)通透性及神经功能的影响.方法 小鼠脑内接种HSV-1病毒,治疗组静脉注射硫酸镁,对照组仅注射等量生理盐水.采用免疫组化技术对感染侧脑组织AQP4蛋白进行检测.通过检测渗出到脑血管外的伊文斯蓝(Evans Blue,EB)的含量来定量观察BBB的通透性.HSV-1病毒感染后5d对小鼠进行神经功能评分.结果 造模后第3天,脑组织AQP4的表达增加,第5天时更加明显(P<0.01),与血脑屏障通透性增高相一致,给与硫酸镁治疗后,血脑屏障通透性及AQP4的表达均明显降低(P<0.01),伴随着神经功能的改善.结论 镁剂能抑制AQP4蛋白的表达,保护BBB,改善脑炎后神经功能.     

大鼠实验性脑出血后血肿周围水通道蛋白-4动态变化的研究

目的研究大鼠脑出血后血肿周围水通道蛋白4(AQP4)的动态变化及其与脑水肿、脑损伤程度的关系。方法采用SD大鼠自体动脉血注入尾状核建立脑出血模型,应用免疫组织化学法、干湿重法、Alexis法分别检测大鼠脑出血后不同时间点血肿周围AQP4、脑组织含水量及神经功能缺损程度的动态变化。结果①血肿周围AQP4在脑出血后12h表达开始增强,1～3d达到高峰,7d后略高于正常,14d基本恢复正常。②脑组织含水量在出血后6h增加,1～3d达到峰值,7d明显减轻,14d基本恢复正常。③神经功能缺损从出血后6h开始,最重的时间点是12h～3d,7d明显减轻,14d基本恢复正常。④脑出血后血肿周围AQP4的表达与脑组织含水量之间存在关联(x2mh=16.49,P<0.05)。⑤脑出血后血肿周围AQP4的表达与神经功能缺损程度之间存在关联(x2mh=15.07,P<0.05)。结论①AQP4的表达与脑水肿、脑损伤的发生发展密切相关,是引起出血性脑水肿脑损伤的重要因素之一。②早期积极控制脑出血后AQP4的过度表达将是减轻和预防脑出血后脑水肿脑损伤的有效途径。     

大鼠尾壳核内注射凝血酶对AQP4蛋白表达的影响

目的研究凝血酶对水孔蛋白-4(aqaporin-4,AQP4)表达的影响及引起脑出血后脑水肿形成的机制.方法在立体定向仪下向大鼠右侧尾壳核注射15 U凝血酶,在不同时间段对注射部位邻近脑组织AQP4蛋白进行免疫组化检测.结果注射凝血酶6 h后尾壳核AQP4蛋白表达开始增高,在第1 d达高峰,并维持到第3 d,以后逐渐下降到正常水平.结论凝血酶能促进脑微血管周围的AQP4蛋白表达的增加,加速水分的跨膜流动,引起星形胶质细胞水肿和血脑屏障的破坏,导致脑出血早期阶段脑水肿的发生.     

亚低温对实验性脑出血后水通道蛋白4表达及脑水肿的影响

目的研究亚低温对脑出血后水通道蛋白4(AQP4)表达及脑水肿的影响,探讨亚低温对出血性脑水肿的作用机制。方法在大鼠苍白球注射胶原酶制作脑出血模型,用冰块降温及白炽灯照射加温的方法调节体温;应用免疫组化方法检测脑组织AQP4表达,采用干湿重法观察脑含水量的动态变化。结果脑出血模型大鼠病灶侧脑含水量、血肿周围AQP4的表达水平明显高于假手术组(均P<0.001);各个时间点亚低温组大鼠病灶侧脑含水量以及血肿周围AQP4的表达水平均明显低于对照组(P<0.05～0.01);AQP4表达水平与脑含水量呈正相关(r=0.977,P<0.001)。结论亚低温能明显减轻脑出血后脑水肿及AQP4的表达,亚低温可能通过抑制AQP4的表达而减轻脑水肿。     

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.