丰富环境对脑损伤后脑功能恢复的作用

目的：自20世纪40年代首次提出丰富环境可促进脑损伤患功能恢复以来，对不同类型的脑损伤动物模型的大量研究均证实了这一观点。随着脑科学和分子生物学研究的进展，有关环境对脑损伤功能恢复的实验研究得到进一步的发展。资料来源：应用计算机检索Medline：1990-01／2004-01和science direct 2000-01／2004-01与丰富环境相关章，检索词为“environmental enrichment，brain damage，synaptic plasticity”，并限定章语言种类为English。资料选择：选择丰富环境应用于脑损伤修复的实验研究方面的献，排除科研设计明显不正确的献及综述献。资料提炼：共检索到35篇英献，排除明显重复和较陈旧献，共纳入11篇。对检索到的丰富环境干预促进脑损伤修复研究方面章中的相关信息进行综述。资料综合：对检索到的章进行分析综合，提示中枢神经系统在结构和功能上具有很强的适应和重塑能力，易受环境和经验的影响，脑损伤后亦如此。脑损伤后神经元的修复是一个非常复杂的过程，丰富环境干预能引起突触结构和功能的变化，促进脑损伤后脑功能的恢复。结论：丰富环境干预可以促进脑损伤后脑功能的恢复，丰富环境刺激还具有神经保护作用，提高中枢神经系统的环境适应能力，降低再次受损的危险性。因此如果将丰富环境结合被动活动和主动学习与训练运用于临床康复中，将会显促进脑损伤后认知能力和感觉运动功能的恢复。     

小胶质细胞与缺血性脑损伤

目的:探讨中枢神经系统固有的免疫效应细胞小胶质细胞在缺血性脑损伤中作用。资料来源:应用计算机检索Pubmed和PML数据库1990-01/2004-08与小胶质细胞和在缺血性脑损伤相关的文章,检索词“mircoglia,is-chemia,braindamage”,限定文章语言种类为English。同时计算机检索中国期刊全文数据库1990-01/2004-08与小胶质细胞和脑损伤有关的文章,限定文章语言种类为中文,检索词“小胶质细胞/脑损伤”。资料选择:对资料进行初审,选取以小胶质细胞活化和脑缺血损伤为主要研究内容的文献,排除脑损伤、脑内炎症与小胶质细胞有关的文献、重复性同一研究的文献以及综述类文献。资料提炼:共搜集到相关文献144篇,其中英文96篇,中文48篇,21篇文献符合小胶质细胞活化和缺血脑损伤的纳入标准。资料综合:对选取的文献进行阅读、归纳及综合。结果显示小胶质细胞在脑损伤中的作用被广泛研究,活化的小胶质细胞通过释放毒性细胞因子和蛋白酶类,增强吞噬作用及启动脑内炎症反应等多种方式参与神经元损伤。结论:脑缺血早期,适当抑制小胶质细胞的活化增殖,可以减轻脑损伤,有助于脑功能恢复。     

小胶质细胞与缺血性脑损伤

目的：探讨中枢神经系统固有的免疫效应细胞小胶质细胞在缺血性脑损伤中作用。资料来源：应用计算机检索Pubmed和PML数据库1990-01／2004-08与小胶质细胞和在缺血性脑损伤相关的文章，检索词“mircoglia，ischemia，brain damage”，限定文章语言种类为English。同时计算机检索中国期刊全文数据库1990-01／2004-08与小胶质细胞和脑损伤有关的文章，限定文章语言种类为中文，检索词“小胶质细胞／脑损伤”。资料选择：对资料进行初审，选取以小胶质细胞活化和脑缺血损伤为主要研究内容的文献，排除脑损伤、脑内炎症与小胶质细胞有关的文献、重复性同一研究的文献以及综述类文献。资料提炼：共搜集到相关文献144篇，其中英文96篇，中文48篇，21篇文献符合小胶质细胞活化和缺血脑损伤的纳入标准。资料综合：对选取的文献进行阅读、归纳及综合。结果显示小胶质细胞在脑损伤中的作用被广泛研究，活化的小胶质细胞通过释放毒性细胞因子和蛋白酶类，增强吞噬作用及启动脑内炎症反应等多种方式参与神经元损伤。结论：脑缺血早期，适当抑制小胶质细胞的活化增殖，可以减轻脑损伤，右助于脑功能恢复。     

脑损伤修复与成体干细胞的可塑性

目的：成体干细胞体在内外可分化为神经细胞而用于脑损伤修复，探讨成体干细胞用于脑损伤康复的可行性可为脑功能恢复的临床实践提供前瞻性依据。资料来源：应用计算机检索Medline 1998-01／2004-04和PubMed 1998-01／2004-04期间的相关文章，检索词“stemcell，cerebralmlury．rehabilitation”，并限定文章语言种类为English。同时计算机检索《中国临床康复》杂志1997-01／2004-04期间的相关文章，限定文章语言种类为中文，检索词“干细胞、脑损伤、康复”。资料选择：对资料进行初审，选取包括成体干细胞分化为神经细胞及其用于脑损伤治疗的实验和l临床研究文献，查找文献全文。资料提炼：共收集到33篇关于成体干细胞可塑性分化及其用于脑损伤的研究文献。资料综合：33篇文献证明了成体干细胞可分化为神经细胞及其可能的机制，并证明了成体干细胞移植治疗脑损伤的有效性。结论：已有研究充分证明成体干细胞在体内外可分化为神经细胞，并可用于脑损伤的修复。     

脑损伤修复与成体干细胞的可塑性

目的成体干细胞体在内外可分化为神经细胞而用于脑损伤修复,探讨成体干细胞用于脑损伤康复的可行性可为脑功能恢复的临床实践提供前瞻性依据.资料来源应用计算机检索Medline 1998-01/2004-04和PubMed1998-01/2004-04期间的相关文章,检索词"stem cell,cerebral injury,rehabilitation",并限定文章语言种类为English.同时计算机检索<中国临床康复>杂志1997-01/2004-04期间的相关文章,限定文章语言种类为中文,检索词"干细胞、脑损伤、康复".资料选择对资料进行初审,选取包括成体干细胞分化为神经细胞及其用于脑损伤治疗的实验和l临床研究文献,查找文献全文.资料提炼共收集到33篇关于成体干细胞可塑性分化及其用于脑损伤的研究文献.资料综合33篇文献证明了成体干细胞可分化为神经细胞及其可能的机制,并证明了成体干细胞移植治疗脑损伤的有效性.结论已有研究充分证明成体干细胞在体内外可分化为神经细胞,并可用于脑损伤的修复.     

丰富环境与神经可塑性

目的:神经系统的发育是遗传因素和环境因素共同作用的结果,丰富环境对脑发育和脑损伤修复具有显著的促进作用,而脑发育与脑损伤修复的基础是神经可塑性。因此,关于丰富环境与神经可塑性的研究已成为脑损伤修复研究的热点。资料来源:应用计算机检索Medline1994-01/2004-08和ELSEVER1997-07/2004-08期间丰富环境与神经可塑性相关的文章,检索词“Enrichedenvironment,Neuronalplasticity”,并限定语言种类为英文。资料选择:对资料进行初审,选出与丰富环境与神经可塑性关系密切的文摘进行全文查找,浏览全文后,筛除重复研究的文献,将最新研究纳入提取精读范围。资料提炼:共收集到19篇符合要求的文献,其中11篇是关于丰富环境、神经可塑性及二者关系的文献,5篇涉及丰富环境的作用机制,3篇为问题与展望。资料综合:丰富环境可以提供多感官刺激、运动和社交的机会,丰富环境即可刺激和引起神经可塑性的变化,神经系统的生长发育及其损伤修复都具有可塑性。丰富环境刺激可引起神经形态学结构及行为学功能的改变,其作用机制与神经生长因子、离子型谷氨酸受体及早期即刻基因等变化有关。结论:丰富环境刺激具有引起神经形态学结构和行为学功能变化的效果,使其成为一种有效而低风险的脑损伤康复手段。     

人脐血细胞分化为神经细胞的体内实验研究

目的:人脐血富含干细胞和前体细胞,本文检索了人脐血治疗中枢神经系统疾病的体内实验研究状况、脐血细胞穿过血脑屏障的机制,并对其临床应用前景进行展望。资料来源:应用计算机检索PUBMED1997-01/2005-10期间的相关文章,检索词为“Humanumbilicalcordbloodcells,nervecell”,并限定文章语言种类为English。同时计算机检索万方数据库2000-01/2005-10期间的相关文章,检索词为″脐血细胞,神经细胞″,并限定文章语言种类为中文。资料选择:对资料进行初审,并查看每篇文献后的引文。纳入标准:文章所述内容应与人脐血细胞的研究相关。排除标准:重复研究或Meta分析类文章。资料提炼:共收集到230篇相关文献,52篇文献符合纳入标准,排除的178篇文献为内容陈旧或重复。符合纳入标准的52篇文献中,36篇涉及人脐血治疗中枢神经系统疾病的体内实验研究状况,11篇涉及脐血细胞穿过血脑屏障的机制,5篇涉及人脐血细胞存在的问题与展望。资料综合:脐血富含干细胞和前体细胞,静脉注射人脐血细胞可进入脑内分化为神经干细胞、神经元和星形胶质细胞,提高脑和外周血神经营养因子水平,促进神经功能恢复。脑损伤后,病变组织表达趋化蛋白和黏附分子并释放多种化学物质及一系列生物活性因子,促使脐血中的骨髓间充质细胞、单个核细胞和造血细胞穿过损伤的血脑屏障进入脑内,向病灶迁移通过促进病灶周围的血管再生从而促进神经再生。脐血静脉移植为治疗神经退行性疾病提供了广阔的前景,脐血来源的干细胞可能将成为组织工程中的种子细胞,将对神经系统的细胞治疗和基因治疗起到极大地推动作用。结论:静脉注射人脐血细胞可进入脑内并分化为神经细胞,对神经功能缺损有改善作用,为脐血移植治疗神经系统疾病提供了新思路。     

骨髓基质细胞移植治疗外伤性脑损伤的效应

目的:综述骨髓基质细胞移植治疗外伤性脑损伤的效应。资料来源:应用计算机检索PUBMED 1996-10/2006-10期间的相关文章,检索词为“bone marrow stromal cells(BMSCs),traumatic brain in jury(TBI),cell transplantation”,并限定文章语言种类为English。资料选择:对资料进行初审,并查看每篇文献后的引文。纳入标准:文章所述内容应与骨髓基质细胞移植治疗外伤性脑损伤研究相关。排除标准:重复研究或Meta分析类文章。资料提炼:共收集到138篇相关文献,31篇文献符合纳入标准,排除的107篇文献为内容陈旧或重复。符合纳入标准的31篇文献中,分别涉及骨髓基质细胞的生物学特性、体外诱导分化、移植途径、对外伤性脑损伤的修复以及修复中枢神经系统损伤的机制。资料综合:骨髓间充质干细胞是一群存在于骨髓中的非造血干细胞,具有较强的自我更新能力和多向分化潜能,在体外不同的诱导条件下可分化为骨细胞、软骨细胞、肌腱细胞、脂肪细胞、神经细胞、平滑肌细胞等多种细胞。通过脑实质内直接注射、脑脊液内注射或血管内注射移植后,骨髓基质细胞可透过血脑屏障集中于损伤区并在中枢神经系统内长时间存活。通过替代受损细胞和激活内源性修复机制,骨髓基质细胞可改善损伤的神经功能、促进外伤后神经重塑。随着对骨髓基质细胞研究的深入,以下几个方面还需进一步研究:骨髓基质细胞特异性标志的确定及快速分离纯化、归巢及体内分化的相关机制、促进损伤后神经组织重塑的分子机制。结论:骨髓基质细胞于脑实质内直接注射、脑脊液内注射或血管内注射移植后均能促进外伤性脑损伤修复,作用机制主要为替代受损细胞和激活内源性修复。目前尚存在一些未解决的问题,但骨髓基质细胞治疗外伤性脑损伤仍是一种很有前途的治疗方法。     

骨髓基质细胞与中枢神经系统损伤和修复

目的:探讨骨髓基质细胞生物学特性、增殖分化能力和在中枢神经系统的多潜能应用及其作用机制。资料来源:应用计算机检索Medline1994-01/2004-12与骨髓基质细胞和中枢神经系统损伤和修复相关的文章,检索词“bonemarrowstemcells,centralnervoussystem,并限定文章语言种类为English,同时计算机检索万方数据库2000-01/2004-12相关的文章,限定文章语言种类为中文,检索词为“骨髓基质细胞,中枢神经系统”。资料选择:就检索到的200余篇文献进行筛选,选择以骨髓基质细胞用于中枢神经系统损伤和修复的基础研究为主要内容的文献60多篇,其中研究内容相似的,以近5年且发表在较权威杂志者优先,排除综述类文献和Meta分析。资料提炼:将筛选的22篇文献进行分类,7篇研究骨髓基质细胞的生物学特性,5篇与骨髓基质细胞增殖分化能力相关,10篇与骨髓基质细胞在中枢神经系统的应用及其作用机制相关。资料综合:骨髓基质细胞修复中枢神经系统损伤有巨大潜力。通过局部、脑室系统及动脉、静脉植入骨髓基质细胞均发现其在中枢神经系统内长时间存活并集中于损伤区,且有着向神经细胞分化的表现。脑内特殊微环境对其迁移、分化起着重要的诱导作用,同时通过移植骨髓基质细胞可改善损伤的神经功能,此外,骨髓基质细胞对中枢神经系统的神经干细胞也有积极的影响作用,可促进神经再生及可塑性的增强。但目前在骨髓基质细胞的分离、鉴别等方面还存在一些问题有待解决。结论:骨髓基质细胞具有多向分化潜能,在适宜条件下可分化为神经元和星形胶质细胞,能在人类中枢神经系统疾病中起到修正和更改的潜在作用,但其对神经功能损伤恢复的具体机制仍不是十分明确。     

骨髓源性神经细胞的现状与展望

目的:了解骨髓基质干细胞向神经细胞分化的内在潜力及分化后神经细胞的结构和功能特点以及电针在神经细胞诱导分化中的应用前景。资料来源:应用计算机检索medline1995-01/2005-03与间质干细胞神经细胞分化相关的文献,检索词“mesenchymalstemcells,neurons”,并限定文章语言种类为“English”。同时检索中国学术期刊全文数据库1994-01/2005-03相关的文献以及与针刺治疗脊髓、脑相关的文献,检索词为“骨髓基质细胞、脊髓/脑”、“针刺、脊髓/脑”,限定语言种类为中文。资料选择:对检索到的100余篇文献进行筛选,选择骨髓基质细胞体内、外分化特性及用于中枢神经系统损伤和修复的基础研究文献40篇,针刺治疗脊髓、脑相关的文献60多篇,其中研究内容相似的,以近5年且发表在较权威杂志者优先,排除综述类文献和Meta分析。资料提炼:将筛选的52篇文献进行分类,7篇研究骨髓基质细胞的生物学特性,11篇与骨髓基质细胞增殖分化能力相关,22篇与骨髓基质细胞在中枢神经系统的应用及其作用机制相关。12篇与针刺抗氧化、促生长因子分泌以及促进内源性神经干细胞增殖相关。进一步选择有代表性的23篇进行综述。资料综合:体内外微环境对骨髓基质细胞的诱导分化起着重要作用,但目前骨髓基质细胞向神经细胞诱导分化的技术还不成熟,诱导率和存活率还较低。结论:骨髓基质细胞在适宜条件下可分化为神经元,如何提高骨髓基质细胞的神经元转化率和存活率是值得进一步探讨的问题。     

Mediators of brain edema and secondary brain damage

Progress is our understanding of the roles of vasogenic and cytotoxic brain edema in secondary brain damage can be expected from studies of the ability of biochemical factors to open the blood-brain barrier, derange the microcirculation, and cause cell swelling and necrosis. Mediator compounds are considered to form or to become released in an area of primarily damaged brain (necrosis) and to enter the cerebral parenchyma through the broken blood-brain barrier from the intravascular space. Many biochemical factors must be considered. We suggested three criteria for determining the roles of mediators: a) they must inflict brain tissue damage, b) they must occur in pathologic concentrations or in compartments not normally present, and c) specific inhibition should attenuate secondary brain damage. These requirements are met by the kallikrein-kinin system and by glutamate. In the case of arachidonic acid and its many metabolites, the concept is difficult to test because fatty acids may be active only if not bound to proteins, and therapeutic inhibition might be difficult. A variety of mediators may enhance each other in a cascade manner by various initiating reactions that might be amenable for pharmacologic inhibition.     

Imaging brain development: the adolescent brain

The past 15 years have seen a rapid expansion in the number of studies using neuroimaging techniques to investigate maturational changes in the human brain. In this paper, I review MRI studies on structural changes in the developing brain, and fMRI studies on functional changes in the social brain during adolescence. Both MRI and fMRI studies point to adolescence as a period of continued neural development. In the final section, I discuss a number of areas of research that are just beginning and may be the subject of developmental neuroimaging in the next twenty years. Future studies might focus on complex questions including the development of functional connectivity; how gender and puberty influence adolescent brain development; the effects of genes, environment and culture on the adolescent brain; development of the atypical adolescent brain; and implications for policy of the study of the adolescent brain.     

Enhanced brain extraction improves the accuracy of brain atrophy estimation

BET (Brain Extraction Tool) is a widely used computer program to automatically separate brain from non-brain structures in MR images. This procedure is used in SIENAX and SIENA, which are robust approaches to quantifying brain volume (atrophy state) and volume change (atrophy rate), respectively. Occasionally, however, BET produces imperfect results (e.g., inclusion of non-brain structures). This is usually either ignored (if inaccuracies are small) or corrected by manual adjustment, with the disadvantages of user intervention. We describe here a new, automated option in BET. This is based on the original BET, but uses standard-space masking to remove tissue around the eyes, and further morphological operations and thresholding to refine eyeball removal and eliminate additional non-brain tissues. To assess whether the new BET procedure improves brain volume measurements, this was compared with the traditional and manual editing procedures in SIENA and SIENAX. Measures of atrophy rate and state were significantly higher with the traditional procedure than with the manual editing and new procedures. In contrast, both atrophy measures were almost identical and highly correlated when the manual editing and new procedures were used. The voxels excluded with these two procedures showed close overlap, as judged by the Dice overlap coefficient. We conclude that, in SIENA and SIENAX, the proposed BET procedure shows results matching those obtained after manual editing, thus more closely approximating the "true" brain volume. Multicentre studies monitoring brain atrophy in clinical trials may receive benefit by using this unbiased, fully automated procedure.     

Effect of brain cooling on brain ischemia and damage markers after fluid percussion brain injury in rats

Although systemic cooling had recently been reported as effective in improving the neurological outcome after traumatic brain injury, several problems are associated with whole-body cooling. The present study was conducted to test the effectiveness of brain cooling without interference with the core temperature in rats after fluid percussion traumatic brain injury (TBI). Brain dialysates ischemia (e.g., glutamate and lactate-to-pyruvate ratio) and injury (e.g., glycerol) markers before and after TBI were measured in rats with mild brain cooling (33 degrees C) and in the sham control group. Brain cooling was accomplished by infusion of 5 mL cold saline via the external jugular vein under general anesthesia. The weight loss was determined by the difference between the first and third day of body weight after TBI. The maximum grip angle in an inclined plane was measured to determine motor performance, whereas the percentage of maximal possible effect was used to measure blockade of proprioception. The triphenyltetrazolium chloride staining procedures were used for cerebral infarction assay. As compared with those of the sham-operated controls, the animals with TBI had higher values of extracellular levels of glutamate, lactate-to-pyruvate ratio, and glycerol in brain and intracranial pressure, but lower values of cerebral perfusion pressure. Brain cooling adopted immediately after TBI significantly attenuated the TBI-induced increased cerebral ischemia and injury markers, intracranial hypertension, and cerebral hypoperfusion. In addition, the TBI-induced cerebral infarction, motor and proprioception deficits, and body weight loss evaluated 3 days after TBI were significantly attenuated by brain cooling. We successfully demonstrate that brain cooling causes attenuation of TBI in rats by reducing cerebral ischemia and injury resulting from intracranial hypertension and cerebral hypoperfusion. Because jugular venipuncture is an easy procedure frequently used in the emergency department, for preservation of brain function, jugular infusion of cold saline may be useful in resuscitation for trauma patients.     

重型颅脑损伤术后顽固性脑蕈的临床分析

目的 探讨重型颅脑损伤术后顽固性脑蕈的形成原因及有效治疗措施。方法 对32例病人进行回顾性分析，总结其形成原因、有效治疗措施。结果 脑水肿、脑积水、颅内感染是重型颅脑损伤术后形成顽固性脑蕈的主要原因，有效运用脱水药物和各种措施降低颅内压、预防感染、保证创口I期愈合是治疗顽固性脑蕈的有效措施。结论 针对不同情况采取相应措施治疗重型颅脑损伤术后顽固性脑蕈，取得较好疗效。     

Human fetal brain imaging by magnetoencephalography: verification of fetal brain signals by comparison with fetal brain models

Fetal magnetoencephalogram (fMEG) is measured in the presence of a large interference from maternal and fetal magnetocardiograms (mMCG and fMCG). This cardiac interference can be successfully removed by orthogonal projection of the corresponding spatial vectors. However, orthogonal projection redistributes the fMEG signal among channels. Such redistribution can be readily accounted for in the forward solution, and the signal topography can also be corrected. To assure that the correction has been done properly, and also to verify that the measured signal originates from within the fetal head, we have modeled the observed fMEG by two extreme models where the fetal head is assumed to be either electrically transparent or isolated from the abdominal tissue. Based on the measured spontaneous, sharp wave, and flash-evoked fMEG signals, we have concluded that the model of the electrically isolated fetal head is more appropriate for fMEG analysis. We show with the help of this model that the redistribution due to projection was properly corrected, and also, that the measured fMEG is consistent with the known position of the fetal head. The modeling provides additional confidence that the measured signals indeed originate from within the fetal head.     

脑胶质瘤中肿瘤干细胞的体外傲射敏感性

背景：目前放疗治疗脑胶质瘤效果不理想,可能因素有很多.目的：探讨脑胶质瘤中肿瘤干细胞的体外放射敏感性.方法：取脑胶质瘤细胞,接种于含生长因子的无血清培养基中培养,取细胞活力最强的位点扩增3-5代的肿瘤球细胞,给予不同X射线剂量照射,检测其细胞活力,以确定最适的放疗剂量.结果与结论：胶质瘤中不同部位的肿瘤细胞增殖活力有差异;8 Gy以上X射线剂量对脑肿瘤干细胞具有显著的杀伤作用.说明脑胶质瘤具有异质性,部位不同,脑肿瘤干细胞增殖活力不同;不同的放疗剂量对脑肿瘤干细胞有不同的影响.