猫内囊组织间液纤维束间隙向脑室的引流

目的：探讨生理状态下猫内囊组织间液在纤维束间隙内的引流方向。方法：将５μｌ印度墨汁０．４μｌ／ｍｉｎ的速度立体定位地注射于猫内囊,在脑切面、２ｍｍ透明脑薄片及石蜡切片上对碳颗粒的扩散和引流途径予以观察。结果：脑切面及透明后的脑薄片显示,墨汁在三个平面上均沿白质扩散;脑室外侧壁轻微黑染。光镜下,墨汁从脑内注射点沿白质纤维网向脑室方向扩散。脑室管膜下,碳颗粒成簇呈线状排列。结论：猫内囊组织间液经纤维束     

大鼠脑内大分子物质的引流通路及方法学研究

为探讨脑内大分子物质的引流通路,本研究微量注射示踪剂墨汁到大鼠右侧尾壳核,Ⅰ组动物使用传统的脑内注射方法,Ⅱ组动物采取改良方法防止示踪剂从进针处进入蛛网膜下腔,术后1、3、7、14、21 d处死动物,分别用肉眼、光镜及电镜观察墨汁在脑内、蛛网膜下腔、颈总动脉及颈部淋巴结的分布。结果显示:墨汁在两组动物脑实质内的分布趋势相同,即在白质内沿神经纤维弥漫性分布,7 d后在灰质内选择性地沿血管周围间隙分布,部分碳颗粒被管周细胞和巨噬细胞吞噬;Ⅱ组动物中观察到墨汁从大脑顶部进入蛛网膜下腔后沿其中的血管周围间隙分布并引流到脑的底部和嗅球及筛板区域,在耳蜗、前庭蜗神经和视神经等的脑神经鞘以及颈总动脉壁和颈部淋巴结有碳颗粒沉积;Ⅰ组动物没有这种分布。以上结果表明,大鼠脑实质内的大分子物质在白质和灰质中的引流方式不同;进入脑脊液的大分子物质可由颈部淋巴系统引流;墨汁不是很好的研究脑实质内大分子物质引流的示踪剂。     

猫内囊组织间液经淋巴管前淋巴系统的引流

目的 探讨内囊组织间液是否经淋巴管前淋巴系统引流,材料和方法：将１０μｌ印度墨汁注射于８例成年猫内囊,在大体,光镜和电镜下对碳颗粒的引流途径予以追踪观察,结果：颈深淋巴结及蛛网膜下腔内和脑表面的动脉黑染,光镜下,颈深淋巴结内有碳颗粒,颈内动脉外段外膜中偶见碳颗粒,颈内动脉颅内段,大脑中动脉,大脑动脉环,蛛网膜下腔内动脉,软膜内小动脉等各动脉外膜中有碳颗粒,周围不存在内皮,电镜下,颈深淋巴结见碳颗粒     

大鼠颈内动脉系的脑淋巴管前淋巴系统

用向大鼠大脑皮质内注射墨汁，电镜下观察示踪物质（碳）的方法，研究了大鼠大脑的淋巴引流途径。结果发现在大脑毛细血管的魏尔啸－罗宾间隙，以及大脑中动脉，颈内动脉的颅内段和颅外段的外膜中均有碳颗粒出现；颈深淋巴结因碳颗粒积聚而变黑，光镜下即可见碳颗粒出一颈大淋巴结髓窦内。上述结果表明颈内动脉系血管外膜中也存在脑的淋巴管前淋巴系统，其功能为引流大脑的淋巴。     

长期舞蹈训练对白质纤维微结构影响的TBSS比较研究

舞蹈涉及复杂的感觉运动信息处理,长期舞蹈训练可能让脑产生功能与结构的可塑性改变。目前关于舞蹈训练导致的白质结构研究相当有限,缺乏统一的结果,因此对舞蹈家与正常对照组的白质纤维微结构指标进行比较研究,以探索舞蹈家白质纤维微结构的特异性改变。采集18名舞蹈家及与之匹配的25名对照被试的磁共振扩散张量成像(DTI)数据,使用基于纤维束示踪的空间统计分析(TBSS)技术,对被试白质纤维的部分各向异性分数(FA)和平均弥散率(MD)图谱进行体素级别统计分析。采用t检验,对比两组被试数据的差异。结果表明,舞蹈家在涉及感觉运动信息处理的白质纤维微结构的一致性降低:在胼胝体压部、左侧内囊前肢(左侧丘脑辐射前部)、左侧内囊后肢(左侧皮质脊髓束)存在显著降低的FA值,在左侧内囊后肢(含部分左侧下纵束、左侧上纵束与左侧皮质脊髓束)、左侧外囊(含部分下额枕束与钩束)、左侧冠状束前部与胼胝体膝部存在显著升高的MD值。以上结果提示,舞蹈训练可能导致脑内特定白质纤维束的交错更多,连接不同脑区的轴突纤维更为发散,进而影响感觉运动信息的上下行传递与左右脑信息整合效率。同时,长期舞蹈训练可能对主导运动控制的左半脑的白质通路影响明显。     

吞噬细胞在脑淋12引流中的作用

目的:研究吞噬细胞在脑淋巴引流中的作用.方法:将荧光蛋白作为脑淋巴引流的示踪剂微量注射到大鼠大脑皮层内,用荧光显微镜观察其在大脑皮层和颈部淋巴结的分布.结果:荧光显微镜下,大脑皮层内可见红色荧光沿血管周围间隙分布,还可见室管膜周围和脑室内有强荧光信号.高倍光镜下,可见大脑皮层内点状散在分布的红色荧光,为吞噬了荧光蛋白的细胞.颈部淋巴结内见红色点状荧光信号沿淋巴窦分布.结论:脑淋巴内的大分子物质可引流到颈部淋巴结.大分子物质在大脑皮层内沿血管周围间隙分布,脑内的吞噬细胞参与脑淋巴内大分子物质的引流.脑淋巴内的大分子物质可沿神经纤维间隙经室管膜进入脑室,加入脑脊液循环.     

吞噬细胞在脑淋巴引流中的作用

目的:研究吞噬细胞在脑淋巴引流中的作用。方法:将荧光蛋白作为脑淋巴引流的示踪剂微量注射到大鼠大脑皮层内,用荧光显微镜观察其在大脑皮层和颈部淋巴结的分布。结果:荧光显微镜下,大脑皮层内可见红色荧光沿血管周围间隙分布,还可见室管膜周围和脑室内有强荧光信号。高倍光镜下,可见大脑皮层内点状散在分布的红色荧光,为吞噬了荧光蛋白的细胞。颈部淋巴结内见红色点状荧光信号沿淋巴窦分布。结论:脑淋巴内的大分子物质可引流到颈部淋巴结。大分子物质在大脑皮层内沿血管周围间隙分布,脑内的吞噬细胞参与脑淋巴内大分子物质的引流。脑淋巴内的大分子物质可沿神经纤维间隙经室管膜进入脑室,加入脑脊液循环。     

磁共振扩散张量成像评价小儿脑病的初步应用

目的应用扩散张量成像（DTI）来进一步评价小儿脑疾病，探讨DTI的诊断价值。方法对15例患各种脑病的小儿进行MRI检查，其中男性10例，女性5例，年龄为生后3天至11岁（平均年龄4．8岁）。采用Philips Intera Achieva 3．0 Tesla的超导MRI仪，用回波平面成像（EPI）的DTI技术，b为800s／mm^2，15个方向。观察彩色分数各向异性（FA）图和三维彩色编码图。结果15例患儿中，发育畸形2例，分别是胼胝体发育不良、巨脑回；脑室旁白质软化（PVL）7例；缺氧缺血性脑病3例；脑软化2例；脑积水1例。在巨脑回病例，常规MRI见右侧脑回发育不良，呈巨脑回畸形，右侧脑室扩大，在DTI上见右侧病变区白质束明显较对侧少。胼胝体发育不良病例在DTI张量图见胼胝体菲薄。在PVL和缺氧缺血性脑病病例均可见白质纤维束在放射冠颜色混杂，方向性混乱。脑软化病例可见白质纤维束部分中断。在脑积水病例可见白质束受压推移。结论DTI能够显示白质束的走向、绕行、交叉及推挤、中断等异常，可能对今后评估小儿脑病的预后转归有帮助。     

应用DTI技术对人脑白质纤维束的初步研究

目的建立扩散张量纤维束成像对人脑白质纤维的显示方法,并应用中国数字化可视人体数据进行对照观察,验证扩散张量成像(DTI)方法的可靠性。方法选择5名健康志愿者进行DTI成像,采用DtiStudio软件进行分析处理,重建出部分各向异性(FA)图、容积比(VR)图、相对各向异性(RA)图、表面扩散系数(ADC)图以及二维彩色张量图。应用中国数字化可视人体数据集断面图像、FA图及彩色FA图进行对照观察,利用fibertracking纤维跟踪软件及3DMRI软件进行三维重建显示脑内主要白质纤维束,辨认脑内白质纤维束的位置、形态。结果应用DTI纤维束成像可以清晰准确地描绘脑白质内主要神经纤维束的解剖图谱,包括联络纤维如弓形纤维、钩束、扣带束、上纵束和下纵束,连合纤维如胼胝体、前连合和穹隆,投射纤维如锥体束、视放射、内侧丘系等。DTI纤维束成像结果与已知解剖知识、中国可视化人体断面图像具有很好的一致性。结论应用DTI纤维束成像可以清晰准确地描绘脑白质内主要神经纤维束的解剖图谱,其结果与中国可视化人体断面图像、已知解剖知识是一致的,应用DTI纤维束成像研究脑内纤维连通性是可靠的。     

基于多模型响应函数约束球面反卷积的纤维方向估计EI北大核心CSCD

约束球面反卷积可以从大脑扩散磁共振成像数据中量化白质纤维取向分布信息,该方法仅适用于单壳的扩散磁共振成像数据;在包含各向同性扩散信号的白质组织中,该方法会提供错误的纤维方向信息。针对这一不足,本文在约束球面反卷积的基础上,结合多壳数据和多种扩散模型下估计的响应函数,提出一种基于多模型响应函数的约束球面反卷积方法。多壳数据可以提高纤维方向估计的稳定性,多模型响应函数可以衰减脑白质中各向同性扩散信号,提供更加准确的纤维方向信息。为了验证算法的有效性,利用模拟数据和来自公开数据库的真实人脑数据进行对比实验。结果表明,本文算法可以衰减白质组织中的各向同性扩散信号,克服部分容积效应的影响,能更准确地进行纤维方向估计;重建的纤维方向分布稳定,伪峰少,而且对交叉纤维的识别能力也更强,为纤维束追踪技术的进一步研究奠定了基础。     

Pathways of Fluid Drainage from the Brain - Morphological Aspects and Immunological Significance in Rat and Man

There is firm physiological evidence for the lymphatic drainage of interstitial fluid and cerebrospinal fluid from the brains of rats, rabbits and cats. The object of this review, is to describe firstly the morphological aspects of lymphatic drainage pathways from the rat brain and secondly, to explore through scanning and transmission electron microscope techniques, the possibility of similar lymphatic drainage pathways in man. Interstitial and oedema fluid spreads diffusely through the white matter in the rat and appears to drain into the ventricular cerebrospinal fluid. In grey matter, however, tracers pass along perivascular spaces to the surface of the brain and into the cerebrospinal fluid. Paravascular compartments in the subarachnoid space follow the course of major arterial branches to the circle of Willis and thence along the ethmoidal arteries to the cribriform plate of the ethmoid bone. Particulate tracers, such as Indian ink, enter channels in the arachnoid beneath the olfactory bulbs and connect directly with nasal lymphatics through channels which pass through holes in the cribriform plate. Proteins and other solutes may also drain along other cranial nerves. Thus, there is a bulk flow pathway for interstitial and cerebrospinal fluid from the rat brain into cervical lymphatics. In man, it is probable that diffuse interstitial drainage of fluid from the white matter occurs in a similar way to that in the rat. Furthermore, the anatomical pathways exist by which bulk drainage of fluid could occur along perivascular spaces from the grey matter into perivascular spaces of the leptomeningeal arteries and thence into the cerebrospinal fluid (CSF).(ABSTRACT TRUNCATED AT 250 WORDS)     

Fiber arrangement of the rat splenic capsule with special reference to elastic fibers

The fiber arrangement of the rat splenic capsule was examined under scanning electron microscope (SEM) after selective removal by chemical maceration of capsule components, in conjunction with examination of thin sections using a transmission electron microscope (TEM). TEM findings were compared to those of the guinea-pig, mouse and dog. Serosal cells of the rat splenic capsule showed labyrinthic channels that consisted of expanded intercellular spaces and tunnel-like spaces or slits in the basal cytoplasm. The channels contained fascicles of collagenous fibrils, forming a loose net on an underlying elastic lamina of densely aggregated elastic fibers. The fibrous tunica was an intermingled layer of elastic and collagenous fibers and sparse interstitial cells. The fibrous components were arranged more densely in the external layer than in the internal layer of the capsule. The elastic lamina comprised the outermost layer of the fibrous tunica in the intertrabecular region, but was situated deep in the trabecular region. Outward branches of the lamina in the trabecular region were arranged in a spiral. Intrachannel fibrillar fascicles were continuous, via fenestrations in the elastic lamina, with thick fascicles of collagenous fibers. The elastic lamina may play a role in effective contraction of whole spleen. In the guinea-pig, mouse and dog, elastic fibers were fragmented and not arranged in laminae. Typical smooth muscle cells were abundant in the dog. The channel spaces in the serosal tunica are discussed from the viewpoint of extravascular lymphatic flow for circulation of the peritoneal serous fluid.     

A multiple streamline approach to high angular resolution diffusion tractography

Diffusion-weighted magnetic resonance imaging has the ability to map neuronal architecture by estimating the 3D diffusion displacement within fibrous brain structures. This approach has non-invasively been demonstrated in the human brain with diffusion tensor tractography. Despite its valuable application in neuroscience and clinical studies however, it faces an inherent limit in mapping fiber tracts through areas with intervoxel incoherence. Recent advances in high angular resolution diffusion imaging have surpassed this limit and have the ability to resolve the complex fiber intercrossing within each MR voxel. To connect the fiber tracts from a multi-fiber system, this study proposed a modified fiber assignment using the continuous tracking (MFACT) algorithm and a tracking browser to propagate tracts along complex diffusion profiles. The Q-ball imaging method was adopted to acquire the diffusion displacements. Human motor pathways with seed points from the internal capsule, motor cortex, and pons were studied respectively. The results were consistent with known anatomy and demonstrated the promising potential of the MFACT method in mapping the complex neuronal architecture in the human brain.     

The ultrastructure of the sheath around chronically implanted electrodes in brain

Summary Insulated, bipolar stainless steel electrodes were chronically implanted in various regions of the cat brain and the long-term structural changes in the tissue surrounding the electrodes were studied by light and electron microscopy.A sheath surrounded and separated the electrode from normal grey or white matter. A layer of foreign body giant cells of variable thickness was formed adjacent to the electrode. This layer was attenuated in some places so that it was unrecognizable by light microscopy. The bulk of the sheath structure consisted of collagen fibrils, leptomeningeal cells and hypertrophied astrocytes. Areas consisting of modified leptomeningeal cells with long thin processes we designated as spongy areas. These have not been previously reported using the electron microscope.Glycogen bodies were seen in leptomeningeal cells.Astrocytes became greatly enlarged and were more numerous in and around the sheath. Oligodendrocytes contained lamellar bodies, and direct continuity was shown between a lamellar body and an adjacent myelin sheath. Myelin was seen in abnormal sites (around oligodendrocytes and neurons) and in unusual configurations.Neuronal changes near the sheath included whorls and stacks of modified endoplasmic reticulum and the presence of cytoplasmic nucleolus-like bodies. Reactive, regenerative and degenerative axons were observed.Blood vessels were more numerous in the sheath and surrounding tissue than normal. Perivascular spaces were prominent even around capillaries and often plasma cells and monocytes were in these spaces. As compared to normal tissue the extracellular space is noticeably increased.Electrodes passing through ventricles were surrounded with a sheath covered with ependymal cells. This sheath was comparable in structure to the sheath present around the electrode in other locations.     

大脑中央核心区白质纤维束解剖

目的采用Klingler纤维解剖技术显露大脑中央核心区白质纤维结构,对其进行系统性描述并测量相关结构。方法采用Klingler纤维解剖技术对8例(16侧)成人尸头标本进行解剖,对大脑中央核心区白质纤维束进行逐层分离,观察其走行特点、与周围结构的毗邻关系,并进行相应数据测量。结果采用Klingler纤维解剖技术可清晰显示大脑中央核心区白质纤维束的形态及其位置,最外囊、外囊与屏状核的相对关系,外囊、内囊与壳核的相对关系。经测量,胼胝体的平均长度与厚度分别为73.06 mm、6.85 mm,松果体与前连合的平均距离为28.01 mm,松果体与穹隆柱的平均距离为26.37 mm,穹窿与胼胝体的垂直距离仅为7.56 mm。结论运用Klingler纤维解剖技术可直观、清晰地显示大脑中央核心区白质纤维束的结构及位置,大脑中线上第三脑室空间狭小,进行临床相关手术时应加以重视。     

Degeneration of hippocampal fibers and spatial memory deficit in the aged rat

Old and young Fisher 344 rats were compared for their ability to learn a delayed alternation task. The old animals displayed significant impairment of alternation learning, and were slower than the young animals. The brains of these animals were examined using a silver degeneration stain, and among old rats there was conspicuous degeneration. The greatest density of degenerating fibers was seen in the hippocampus and in anatomically related tracts, but there was substantial fiber staining in the corpus callosum, anterior commissure, and internal capsule. Examination of the young brains revealed only an occasional fiber. There were no signs of cortical atrophy in the old animals. The histopathology of the aged animals' hippocampus and fiber tracts supports the possibility that the delayed alternation impairment shown by these animals was a result of age related degenerative changes.     

丘脑中央外侧核内的大脑皮质体感Ⅰ区下行纤维终末溃变的电子显微镜观察

本文采用多点连续电解毁损法对猫脑左侧皮质体感Ⅰ区进行损毀。用光镜和透射电镜对丘脑左侧中央外侧核内的溃变成分进行了观察。实验结果表明皮质体感Ⅰ区发出纤维通过内囊至中央外侧核后部,并与该部神经元形成突触,其中以轴-树突触较多,且以不对称型者居多。