一氧化氮合酶在继发癫痫的脑膜瘤中表达及其生物学意义

目的探讨一氧化氮在脑膜瘤继发癫痫的发病机制中的作用。方法运用SABC免疫组化方法研究了一氧化氮合酶三种亚型在继发术前癫痫的脑膜瘤标本中的表达。结果在实验组与对照组脑膜瘤的组织切片中,诱生型一氧化氮合酶(iNOS)表达有非常显著性差异(P<0.01),神经元型一氧化氮合酶(nNOS)的表达有显著性差异(P<0.05),内皮组织型一氧化氮合酶(eNOS)的表达没有统计学意义(P>0.05)。结论一氧化氮参与了脑膜瘤继发的术前癫痫发作病理过程,iNOS是诱发脑膜瘤继发术前癫痫的内源性一氧化氮的主要合酶,nNOS可以增强iNOS的诱导作用。     

美满霉素改善血管性痴呆大鼠认知功能损伤并抑制氧化应激

目的 观察美满霉素(minocycline)对血管性痴呆大鼠学习记忆功能和脑组织内皮型一氧化氮合酶(endothelial nitric oxide synthase,eNOS)、诱导型一氧化氮合酶(inducible nitric oxide synthase,iNOS)表达的影响,探讨美满霉素对血管性痴呆的脑保护作用的机制.方法 Wistar大鼠随机分为假手术组(S组)、痴呆模型组(M组)、美满霉素治疗组(MT组).RT-PCR和免疫组织化学法检测大鼠脑组织eNOS、iNOS的表达,行为学检测大鼠学习记忆功能的改变.结果 M组与S组行为学检查显示,M组大鼠有显著学习记忆障碍(P＜0.01),MT组与M组比较行为学检测结果显示,MT组大鼠学习记忆障碍有显著改善(P＜0.01).MT组iNOS表达较M组降低(P＜0.01),MT组eNOS表达较M组增高(P＜0.05);MT组eNOS、iNOS表达较S组增高(P＜0.01);M组eNOS、iNOS表达较S组显著增高(P＜0.01).结论 美满霉素能降低血管性痴呆大鼠脑组织iNOS表达,增强eNOS表达,抑制氧化应激反应,发挥脑保护作用.     

一氧化氮合酶在脑缺血再灌注中的双重作用

目的 探讨短暂脑缺血再灌注后大鼠脑内3型一氧化氮合酶(nitric oxide synthase，NOS)的表达及作用，为脑缺血治疗提供理论依据。方法 采用免疫组织化学方法，用3型NOS的多克隆抗体检测大鼠局灶性脑缺血2h再灌注15min及22h NOS在脑内的表达情况。结果 大鼠脑缺血2h再灌注15min，在脑缺血边缘区的血管壁及神经细胞出现内皮型一氧化氮合酶(endothelial nitric oxide synthase，eNOS)上调表达；脑缺血2h再灌注22h，在脑梗死区内表达神经元型一氧化氮合酶(neuronal mitric oxide synthase，nNOS)的神经细胞减少，并出现表达诱导型一氧化氮合酶(inducible nitric oxide synthase，iNOS)的胶质细胞，同时梗死边缘区血管及神经细胞出现eNOS及iNOS的上调表达。结论 在短暂脑缺血再灌注早期，缺血区周围可能有eNOS相关的保护机制；亚急性期eNOS及iNOS的保护及损伤机制并存；因此，在短暂脑缺血早期恢复灌注后予选择性iNOS抑制剂及促进eNOS活性有可能减少迟发性神经损伤。     

重症肌无力患者IgG对大鼠脑内NOS不同时间表达的影响

目的观察重症肌无力(myasthenia gravis,MG)患者IgG(AchRab)对大鼠脑内一氧化氮合酶(NOS)表达的影响,探讨NOS在MG中造成中枢神经系统损害的机制.方法将AchRab IgG或健康人的IgG注入大鼠侧脑室,1次/d,连续4次.免疫组化方法观察不同时间点大鼠脑皮质、海马及杏仁核神经元型一氧化氮合酶(nNOS)和诱导型一氧化氮合酶(iNOS)的表达变化.结果侧脑室注射后1周实验组大鼠皮质、海马神经元nNOS表达量明显减少,后2周实验组皮质、海马神经元nNOS表达下降更为明显,同时杏仁核神经元nNOS表达量也减少;实验组及对照组脑内细胞均未见iNOS表达.结论AchRab侧脑室内注射可引起大鼠皮质、海马及杏仁核神经元nNOS表达量减少,且2周内这种减少效应随时间延长而增强,但未能诱导脑内细胞iNOS表达,提示AchRab尚可通过抑制大鼠中枢神经系统nNOS表达,降低脑内正常的一氧化氮浓度,减弱一氧化氮对脑组织的保护作用,增加神经元的易损性.     

颅脑损伤后局部组织一氧化氮合酶表达的实验研究

目的研究一氧化氮合酶(nitricoxidesynthase,NOS)基因在实验性大鼠颅脑创伤后局部组织中表达.方法应用免疫组化技术和高清晰度彩色病理图像分析系统,对大鼠脑组织神经细胞中诱导型一氧化氮合酶(iNOS)的表达进行了检测.结果颅脑创伤后大鼠局部及周围神经细胞中有NOS阳性产物表达并具时程特点,伤后2h平均积分光密度(ODI)较0.5h升高不显著(P0.05),伤后6h、12h、24hODI较0.5h升高非常显著(P<0.01).结论在急性脑损伤后的病理过程中,脑组织中诱导型一氧化氮合酶被大量合成,可能是造成机体一氧化氮(Nitricoxide,NO)升高的直接原因.     

一氧化氮和一氧化氮合酶在大鼠局灶性脑缺血中的表达特点

目的建立脑缺血SD大鼠模型,探讨一氧化氮(NO)和一氧化氮合酶(NOS)在脑缺血模型中的表达特点。方法应用线栓法制作大脑中动脉阻塞(MCAO)局灶性脑缺血模型,根据缺血不同时间分为8组,设立假手术组和正常对照组,每组各有6只大鼠。应用硝酸还原酶法测定脑组织NO的含量,流式细胞术(FCM)定量检测硝基酪氨酸(NT)表达,化学比色法测定脑组织NOS的活性,免疫组织化学方法定位检测eNOS、nNOS和iNOS表达位置,逆转录反应系统(RT-PCR)半定量分析eNOS、nNOS和iNOS的 mRNA在脑缺血区域的表达。结果神经功能缺失评分发现缺血时间越长,神经功能缺失越明显;脑组织中NO含量与缺血时间正相关;缺血1h后NT阳性细胞百分比开始明显升高(9.50%);缺血0.5h时NOS的活性开始升高,缺血3d达到高峰[0.94nmol/(g.min)];免疫组织化学提示eNOS在神经细胞和血管内皮细胞胞浆均有表达,nNOS和iNOS抗体主要在神经细胞胞浆中表达;RT-PCR半定量分析在缺血早期(0.5h~6h),随着缺血时间延长,eNOS和nNOS表达增加,iNOS未见表达或低表达;缺血中晚期(6h~5d),iNOS高表达,并与缺血时间呈正相关,eNOS和nNOS表达明显减少。结论脑缺血时间延长,NOS的活性升高,NO在体内特异性代谢产物NT量增加,神经功能缺失越明显;NOS在缺血早期以eNOS和nNOS为主,在缺血晚期以iNOS为主。     

血管内一氧化氮合酶基因转染预防脑血管痉挛的实验研究

目的采用血管内基因转染的方法,将重组内皮型一氧化氮合酶(eNOS)基因转染入蛛网膜下腔出血(SAH)后迟发性脑血管痉挛大鼠脑动脉,探讨防治SAH后迟发性脑血管痉挛的新方法。方法首先构建携带eNOS基因的重组腺病毒。采用小脑延髓池二次注血法建立大鼠SAH后迟发性脑血管痉挛模型。通过颈动脉微泵持续滴注方法进行基因转染,并设置对照组。结果第7天采用免疫组化证实重组eNOS基因表达,重组eNOS主要表达于内皮层。第7天显微镜下测定血管内eNOS转染组脑动脉环平均直径较单纯SAH组增大,电镜观察血管痉挛较单纯SAH组减轻。结论通过本研究证实采用颈动脉微泵持续滴注方法可在大鼠脑动脉表达重组eNOS,重组基因主要表达于动脉内皮细胞,可达到缓解SAH后迟发性脑血管痉挛的目的。     

一氧化氮合酶及血红素氧化酶在颈动脉粥样硬化斑块中的表达

目的 探讨内皮型一氧化氮合酶(eNOS)、诱导型一氧化氮合酶(iNOS)和血红素氧化酶-1(HO-1)在动脉粥样硬化过程中表达的变化及相互关系.方法 选取10例经颈动脉内膜剥脱术取下的粥样硬化斑块标本,以10例正常颈内动脉为对照,用免疫组化方法检测eNOS、iNOS及HO-1在两组颈动脉内的表达,应用统计学的方法对结果进行分析.结果 (1)eNOS在粥样硬化斑块中表达较正常颈动脉表达明显减弱(P<0.001);(2)iNOS在正常颈动脉中没有表达,但在粥样硬化斑块中的平滑肌细胞以及泡沫细胞中有明显表达;(3)HO-1仅在正常颈动脉内皮细胞中表达,而在粥样硬化斑块中,HO-1不仅在内皮细胞中表达,而且在平滑肌细胞以及泡沫细胞中也有较高表达,与正常组相比其表达明显增高(P<0.001);(4)统计分析显示:eNOS阳性表达与iNOS阳性表达呈负相关(r=-0.680,P<0.001),iNOS阳性表达与HO-1阳性表达呈正相关(r=0.898,P<0.001),eNOS阳性表达与HO-1阳性表达呈负相关(r=-0.713,P<0.001).结论 随着动脉粥样硬化的形成,eNOS产生减少而iNOS和HO-1产生增多,一氧化氮合酶及血红素氧化酶在动脉粥样硬化中显示互补及代偿性调节的作用.     

一氧化氮合酶在并发癫的脑膜瘤中的表达及其生物学意义

目的探讨一氧化氮在脑膜瘤并发癫的发病机制中的作用。方法SABC法研究一氧化氮合酶的3种亚型在并发术前癫的脑膜瘤患者的肿瘤切除标本中的表达。结果脑膜瘤的组织切片中,nNOS呈散在分布,eNOS沿肿瘤内的血管壁分布,iNOS则呈点状或片状分布;按WHO的脑膜瘤恶性程度分类标准,nNOS和iNOS的表达有显著性差异;按WHO的脑膜瘤组织病理分类标准,eNOS在血管瘤型脑膜瘤中的表达与其在其他组织病理类型的脑膜瘤的表达之间有显著性差异;按脑膜瘤的不同原发部位划分,nNOS的表达在额叶、顶叶和颞叶有显著性差异,iNOS的表达在各部位均有显著性差异。结论NO参与脑膜瘤术前并发癫的发作病理过程,iNOS是诱发脑膜瘤术前并发癫的内源性NO的主要合酶,nNOS增强iNOS的诱导作用。     

大剂量伽玛刀照射后脑组织一氧化氮合酶亚型表达改变及其与急性脑水肿的关系

目的探讨大剂量伽玛刀(γ刀)照射后脑组织一氧化氮合酶(NOS)亚型表达改变及其与急性脑水肿的关系。方法200Gy量γ刀照射正常大鼠脑,采用光镜、电镜、免疫组化及原位杂交技术研究照射后急性脑水肿的发生发展及脑组织NOS亚型表达变化。结果①照射后30min出现急性脑水肿病理改变,照射后2h出现明显血管源性脑水肿,照射后6h出现明显细胞性脑水肿,照射后3d急性脑水肿达高峰。②脑组织NOS亚型表达在照射后30min开始增高,内皮型一氧化氮合酶(eNOS)及诱导型一氧化氮合酶(iNOS)表达分别于照射后2h及6h显著增高,神经元型一氧化氮合酶(nNOS)表达亦增高,但nNOS阳性表达细胞数量较少。3种NOS亚型表达增高持续时间长,伴行于脑水肿的急性发展阶段。结论大剂量γ刀照射后脑组织NOS亚型表达增高与急性脑水肿的发生发展有关。     

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.     

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.     

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.     

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.     

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.     

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.