Characterization of a synaptiform transmission between a neuron and a glial cell in the leech central nervous system

The cross-talk between neurons and glial cells is receiving increased attention because of its potential role in information processing in nervous systems. Stimulation of a single identifiable neuron, the neurosecretory Leydig interneuron in segmental ganglia of the leech Hirudo medicinalis, which modulates specific behaviors in the leech, evokes membrane hyperpolarization directly in the giant glial cell (Schmidt and Deitmer. Eur J Neurosci 11:3125-3133, 1999). We have studied the neuron-to-glia signal transmission in the voltage-clamped giant glial cell to determine whether this interaction exhibits properties of a chemical synapse. The glial response had a mean latency of 4.9 s and was dependent on the action potential frequency; the glial cell responded to as few as five Leydig neuron action potentials in 50% of the trials. The glial current was sustained for minutes during repetitive Leydig neuron activity without any sign of desensitization. The current was sensitive to tetraethylammonium, and its reversal potential of -78 mV shifted with the external K+ concentration. The glial response increased with the duration of the neuronal action potentials and was sensitive to the external Ca2+/Mg2+ concentration ratio. The results suggest that Leydig neuron activity leads to a Ca2+-dependent release of transmitter from the neuronal dendrites, evoking an K+ outward current in the giant glial cell, implying a synapse-like transmission between a neuron and a glial cell.     

An antiserum to locust adipokinetic hormone reveals a novel peptidergic system in the rat central nervous system

Using an antiserum to locust adipokinetic hormone I, a novel peptidergic system was identified in the rat central nervous system. Immunoreactive fibers were present in the hypothalamic median eminence and periventricular nucleus and the spinal cord dorsal horn, intermediolateral cell column and sacral parasympathetic nucleus. Immunoreactive cells were present in the dorsal gray commissure of lumbosacral spinal cord, the hypothalamic periventricular nucleus and cerebral cortex.     

Benign isolated arteritis of the central nervous system

We present a case of benign isolated arteritis of the CNS. The clinical and angiographic features of this rare disease are discussed and compared with similar cases published in the recent literature.

The importance of the angiographic patterns in the diagnosis of this treatable disease is stressed     

Reductive metabolism of ascorbic acid in the central nervous system

Rat and feline brain and feline spinal cord were examined for the presence of semidehydroascorbate reductase (EC 1.6.5.4) and dehydroascorbate reductase (EC 1.8.5.1). Semidehydroascorbate reductase (SDAR), as monitored by both ascorbyl radical-dependent nicotinamide adenine dinucleotide (NADH) oxidase activity and NADH-dependent ascorbyl radical quenching, was present in all tissues studied. Rat cerebrum exhibited the highest levels and feline spinal cord the lowest. SDAR activity was about twice as high in feline cerebral cortex as in underlying white matter, and paralleled ascorbic acid levels. Subcellular fractionation of rat cerebrum localized most SDAR in a large granular fraction. In contrast, dehydroascorbate reductase was not detectable in any of the tissues examined. The results suggest that semidehydroascorbate reductase is the major enzyme catalyzing the regeneration of reduced ascorbic acid in the central nervous system.     

Expression of Nogo-A mRNA after injury of the rat central nervous system

BACKGROUND： Nogo protein has been identified as an inhibitor of axonal growth, which was highly expressed in central nervous system; however, there are only a few studies on changes of Nogo-A expression following central nervous system injury. OBJECTIVE： To investigate the dynamic expression of Nogo-A mRNA after rat central nervous system injury. DESIGN： Randomized controlled animal study. MATERIALS： Thirty-five rats were randomly divided into two groups, normal animal group （n = 5） and model group （n = 30）. The model group was then divided into six subgroups at six time points： 12, 24 hours and 3, 9, 15, and 21 days post-injury, with five rats in each subgroup. METHODS： The left parietal lobe of rats was contused by free-fall strike, and total RNA was extracted from the entire brain tissue. Semi-quantitative RT-PCR was used to detect Nogo-A mRNA expression, and the ratio between expression of the target gene and glyceraldehyde phosphate dehydrogenase was used to determine the relative expression level. MAIN OUTCOME MEASURES： To determine whether Nogo-A mRNA expression was higher than usual following brain injury. RESULTS： The level of Nogo-A mRNA started to increase 12 hours after injury （P 〈 0.05） and decreased slightly by 24 hours post-injury. Expression increased again on day 3 and reached a peak on day 9. Nogo-A mRNA expression started to decrease on day 15, and then decreased to normal levels at days 21 （P 〉 0.05）. CONCLUSION： After injury of the central nervous system, Nogo-A may play a pivotal role in obstructing regeneration of the nerve.     

中枢神经系统基因治疗的病毒载体

重组病毒载体因其自然感染途径而成为有效的基因转移手段。迄今为止，许多病毒载体，包括逆转录病毒、腺病毒、单纯疱疹病毒、腺相关病毒、慢病毒及多种杂交型病毒载体等，已应用于中枢神经系统基因治疗的基础和临床研究。本对其主要研究进展进行了综述。     

24例原发性中枢神经系统血管炎患者的MRI表现

目的观察24例原发性中枢神经系统血管炎(PACNS)的磁共振成像(MRI)表现,探讨PACNS的MRI诊断价值。方法对急性期进行了MRI检查的24例经病理证实的PACNS的MRI特点进行了回顾性分析。结果 24例患者中,病灶以幕上多见[19例(79.2%)],最常累及颞叶、额叶、顶叶及基底节区(包括丘脑),分别为13例(54.2%)、10例(41.7%)、8例(33.3%)、8例(33.3%);大部分病灶累及双侧大脑半球[15例(72.5%)],灰质和白质均受累[21例(87.5%)]。MRI上病灶可多发或单发,均为12例(50%)。病灶形态大致可分为四种类型:斑片状、肿块样、脑回状和混合性,分别为12例(50%)、8例(33.3%)、2例(8.3%)和2例(8.3%)。MRI上所有病灶均呈长(稍长)T1WI、长(稍长)T2WI异常信号,增强扫描可见病灶均有强化,FLAIR上均呈高或稍高信号,9例(37.5%)病灶中心呈散点状短T1WI、短T2WI混杂信号。17例行DWI和ADC序列检查者中,9例(52.9%)在DWI上呈高(稍高)信号,ADC上呈等信号或混杂信号影,8例(47.1%)在DWI及ADC上呈等信号。11例行GRE序列检查者,8例(72.7%)可见病灶局部有点状低信号影或病灶周围血管影增粗,余3例未见异常。8例行MRA序列检查者,仅1例发现异常,可见病灶供血区相应血管局部有狭窄。结论本组24例PACNS患者急性期头MRI均有异常,表现多样,病灶以幕上多见,可累及各个脑区,病灶可多发或单发,多数灰白质均受累。其形态可表现为斑片状、肿块样、脑回状或混合性,增强扫描均可见强化,以斑片状或脑回样强化多见。头MRI上病灶多变、灰白质受累、斑片状或脑回样强化等表现对PACNS诊断有一定提示性。     

中枢神经病毒感染的病理及生物化学机制

近年来在中枢神经系统(CNS)病毒感染发病机制的认识上取得较大进展。本综述了病毒的传播、细胞群的选择性易损性、病毒的组织亲嗜性和神经毒力特性在CNS感染发病机制中的作用。病毒产生有意义的CNS感染的潜力差异极大，CNS感染的发病取决于病毒对神经的亲嗜性，分子病毒学的研究强调了影响和决定这种亲嗜性的机制，包括病毒和宿主两方面的遗传因素。     

中枢神经系统黑色素瘤的诊治

目的 总结中枢神经系统黑色素瘤的临床特征及诊治经验.方法 回顾性分析6例中枢神经系统黑色素瘤病人的临床资料,肿瘤位于颈椎椎管内1例,颅后窝1例,大脑半球4例.临床表现依据肿瘤所在位置而不同,临床症状、体征无特异性.术前影像学误诊率达67%.结果 手术治疗5例,其中显微镜下全切除4例,次全切除1例;放射治疗1例.5例行病理检查显示:恶性黑色素瘤3例,良性2例.随访5例,3例恶性黑色素瘤病人死亡,2例良性黑色素瘤病人存活.结论 原发于中枢神经系统的恶性黑色素瘤及转移性黑色素瘤预后差,应在手术基础上采取综合治疗;而良性黑色素瘤应尽可能全切,术后预后良好.     

Primary central nervous system lymphoma: a retrospective study

Eleven patients with primary central nervous system lymphoma (PCNSL) proven with biopsy between January 1991 and September 1995 were analysed according to the location of lesions, pathological studies, treatment and outcome. The ages of these patients ranged from 25 to 74 years with an average of 51.4 years. The male to female sex ratio was 6 to 5. The most frequent sites of lesions were frontal lobes. One patient had only leptomeningeal involvement. All intracranial PCNSL in this report arose from B cells; the leptomeningeal PCNSL case was the only one which arose from T cells. All patients received chemotherapy with or without radiotherapy, except two patients who did not receive any treatment. The results of treatment were generally poor. The survival time of patients who died ranged from 2.5 months to 45 months with a median of about 12.5 months. If a combined treatment is to be considered, the possibility of complications such as leucoencephalopathy should be taken in account.     

中枢神经系统复发性血管外膜细胞瘤临床特点分析

目的探讨中枢神经系统复发性血管外膜细胞瘤(HPC)的临床特点。方法回顾性分析46例复发性HPC病人的临床资料,均行手术全切除或次全切除肿瘤,其中辅助放疗29例,辅助伽玛刀治疗7例。采用统计学分析复发性HPC病人术后的生存期及生存期的影响因素。结果 46例病人术后随访3~164个月,平均生存期为(41.6±4.4)个月,术后1、2、3、4年生存率分别为80.4%、65.2%、59.2%和53.8%。所有复发性HPC病人中,复发1次30例,其平均生存期为(36.9±4.1)个月;复发2次及以上16例,其平均生存期为(39.7±7.0)个月。随访期间死亡18例,其平均生存期为(14.2±5.6)个月;存活28例,其平均KPS评分为(86.8±14.2)分。经统计学分析:复发性HPC病人的生存期与性别及肿瘤部位、大小、质地、病理分级之间无相关性(P0.05);复发1次与复发2次及以上病人的生存期间亦无显著差异(P0.05)。结论积极综合治疗复发2次及以上的HPC病人,预后仍可令人满意。     

中枢神经系统血管周细胞瘤诊治分析

目的：探讨中枢神经系统血管周细胞瘤的临床特点及其治疗方法。方法回顾分析14例中枢神经系统血管周细胞瘤患者的临床资料,随访5～100个月,并进行文献复习。结果14例患者均行手术,术后病理明确诊断。肿瘤全切除8例,大部切除3例,部分切除3例。肿瘤复发7例（50％,4例为全切除,1例大部切除,2例为部分切除,术后均未曾放疗）,中位复发时间39个月,全切术后中位复发时间41．5个月,未全切除中位复发时间17个月。复发后再次手术及术后放疗仍可获得较长时间生存。结论血管周细胞瘤诊断依赖于病理,目前手术及术后放疗是较好的治疗办法,手术切除的完整性尤为重要。     

T-lymphocyte entry into the central nervous system

The entry of T-lymphocytes into the parenchyma of the central nervous system is a critical early feature in the pathogenesis of many experimental and spontaneously occurring immune-mediated illnesses. The physiological mechanisms controlling this entry have not been elucidated. This study reports that T-cell entry into the rat CNS appears to be primarily dependent upon the activation state of the lymphocytes; T-lymphoblasts enter the CNS (and all other tissues examined) in an apparently random manner while T cells not in blast phase are excluded. Antigen specificity, MHC compatibility, T-cell phenotype, and T-cell receptor gene usage do not appear related to the ability of cells to enter. This study demonstrates that when T-lymphoblasts are introduced into the circulation they rapidly appear in the CNS tissue. Their concentration in the CNS reaches a peak between 9 and 12 hr, and lymphocytes which have entered, exit within 1 to 2 days. Cells capable of reacting with a CNS antigen remain in the tissue or cyclically reenter to initiate inflammation if they are able to recognize their antigen in the correct MHC context. This observation also appears to pertain to the entry of activated T cells into many other tissues, although their concentrations in these non-CNS sites was not quantitated.     

Segmental differentiation in the leech central nervous system: proposed segmental homologs of the heart accessory neurons.

As part of an on-going study of segmental differentiation in the central nervous system (CNS) of the leech Hirudo medicinalis, a search was made for putative segmental homologs of the heart accessory (HA) neurons, which exist exclusively as a bilateral pair in the ganglia of the fifth and sixth body segments. As it is not yet feasible to obtain adequate cell lineage information in H. medicinalis, potential homologs of the HA neurons were determined using morphological, immunohistochemical, and electrophysiological criteria. Among cells in other body ganglia with somata in the same locations as HA neurons, a pair was found having extensive morphological and physiological similarities to HA neurons. These we have called HA-like (HAL) neurons. Adult HA and HAL neurons have closely related patterns of primary branching, in terms of shape, intraganglionic pathways taken, and extraganglionic projections. The number, location, and relative thickness of branches are also similar among these cells. In embryos 10 to 11 days old, HA and HAL neurons have virtually identical branching patterns, with primary and secondary branches of nearly uniform caliber. Differences in branch thickness develop gradually; by embryonic day 20, they resemble those found in adult neurons. Two features found to differ between HA and HAL neurons were the cell body diameter (larger for the HA cells) and the expression of antigens recognized by the monoclonal antibody Laz1-1 (absent at a detectable level in the HA neurons). At a physiological level, the HA and HAL neurons showed action potentials of similar size and shape, as well as inhibitory synaptic inputs from a common source, the heart interneurons (HN). The observations presented here suggest that there is a common developmental origin for the HA and HAL neurons, and hence that their fates are positionally determined by as yet unknown factors.     

原发性中枢神经系统血管炎的临床特点

目的探讨原发性中枢神经系统血管炎(PACNS)的临床特点。方法对27例PACNS患者的临床资料进行分析。结果PACNS好发于中青年,呈急性或亚急性起病,临床表现以头痛、大脑皮质功能减退、局灶性神经功能缺损及癫疒间样发作为主;头颅MRI示病灶处呈长T1、长T2改变,多有强化;脑组织病理检查示软脑膜血管炎性改变。经糖皮质激素以及抗血小板聚集、清除自由基、降低颅内压、改善微循环等综合治疗,病情明显改善。结论PACNS临床表现多样,综合临床表现、影像学及脑组织活检可作出诊断;应用糖皮质激素治疗可显著提高疗效。     

原发性中枢神经系统恶性淋巴瘤的诊断与治疗

目的探讨原发性中枢神经系统恶性淋巴瘤（PCNSL）的临床特征及诊疗经验。方法回顾性分析13例确诊为PCNSL患者的临床资料。结果11例经立体定向穿刺活检,2例经手术切除病理确诊。术后均接受放疗和化疗。随访3例分别死于确诊后3月、11月、18月,2例存活已超过3年,2例已超过2年,2例已超过1年,确诊不到1年的4例生存良好。结论对影像学高度怀疑PCNSL的病人主张选择立体定向穿刺活检确诊,对有脑疝倾向或脑疝的病人仍需要开颅手术切除肿瘤。确诊后,以小剂量放疗＋化疗的综合治疗疗效较好。     

Disseminated intraparenchymal microgranulomas in the brainstem in central nervous system sarcoidosis

We report a 70‐year‐old woman with sarcoidosis and multiple cranial nerve palsy. The patient suffered from dysarthria, dysphagia and weakness of the upper and lower extremities and died of sepsis. No abnormalities were noted in brain MRI. At autopsy, numerous epithelioid granulomas with Langhans giant cells were present in the bilateral lungs, including the hilar lymph nodes. The brain had a normal external appearance. Histologically, there were brainstem parenchymal lesions consisting of many microgranulomas, lymphocytic infiltration, activated microglias and astrocytosis. Perivascular lympocytic cuffing was also seen. Neither granulomas nor lymphocytic infiltration were seen in the leptomeninges. The present case was considered to be a peculiar type of neurosarcoidosis, that is, “sarcoid brainstem encephalitis”.     

原发性中枢神经系统淋巴瘤诊疗进展

原发性中枢神经系统淋巴瘤(PCNSL)是一种罕见的结外非霍奇金淋巴瘤,可累及脑,眼、软脑膜以及脊髓,具有高度侵袭性.PCNSL对放化疗及免疫治疗敏感,但单方案常短期内复发.目前公认的治疗包括诱导治疗和巩固治疗.本文就原发性中枢神经系统淋巴瘤的发病、进展以及治疗的研究进展做一综述.     

The promise of exosome applications in treating central nervous system diseases

Exosomes (EXs), a type of extracellular vesicles, are secreted from virtually all types of cells. EXs serve as cell-to-cell communicators by conveying proteins and nucleic acids with regulatory functions. Increasing evidence shows that EXs are implicated in the pathogenesis of central nervous system (CNS) diseases. Moreover, EXs have recently been highlighted as a new promising therapeutic strategy for in vivo delivery of nucleotides and drugs. Studies have revealed that infusion of EXs elicits beneficial effects on the CNS injury animal models. As compared to cell-based therapy, EXs-based therapy for CNS diseases has unique advantages, opening a new path for neurological medicine. In this review, we summarized the current state of knowledge of EXs, the roles and applications of EXs as a viable pathological biomarker, and EX-based therapy for CNS diseases.     

原发性中枢神经系统淋巴瘤影像学特征和疗效分析

目的探讨原发性中枢神经系统淋巴瘤(primary central nervous system lymphoma,PCNSL)的影像学诊断、治疗及预后,提高临床对PCNSL的认识。方法回顾性分析经术后病理证实的30例免疫正常的原发性中枢神经系统淋巴瘤患者的临床资料。单纯手术8例,手术+化疗14例,手术+化疗+放疗8例。Kaplan-Meier法分析患者生存期。结果PCNSL临床表现主要为颅内压增高和神经功能缺损为主,误诊率高达93.3%。24例PCNSL(占80.0%)MRI明显均匀强化,表现为团块状及结节状强化,或出现具有特异性的"缺口征"、"尖角征"。病理检查均为B细胞淋巴瘤,以弥漫性大B淋巴瘤最多见。Kaplan-Meier分析全组中位生存期32.0个月,2年生存率46.7%。手术+化疗(中位生存期29个月)及手术+化疗+放疗组(34个月)的生存期高于单纯手术组(3个月)。手术+化疗组(64.3%)及手术+化疗+放疗组(62.5%)的2年生存率均高于单纯手术组(0)。放化疗患者肿瘤全切组与次全切组的生存率未见明显的统计学差异(P>0.05)。结论原发性中枢神经系统淋巴瘤影像学缺乏特异性,易误诊;单纯手术治疗不是首选,应尽早采取以放、化疗为主的全身综合治疗。