齿状核微血管构筑的研究

应用１２例经甲醛碳素黑水灌注的儿童脑及１０例经红色乳胶灌注的成人脑，光镜及手术显微镜下观察齿状核微血管构筑形式。齿状核动脉直接起自小脑三对脉的１－２级分支，分为齿状核内动脉及齿状核外动脉。     

幼儿基底神经节微血管构筑

目的:观察幼儿基底神经节微血管构筑的形态学特点.方法:采用改良碱性磷酸酶染色法显示幼儿基底神经节的微血管形态及吻合.结果:本实验成功地显示出微静脉,且观察到微动脉和微静脉间的吻合.基底神经节各核团内的微动脉有两种类型即长微动脉和短微动脉.其走行迂曲,多为树根状、树藤状和弓状,分支以大锐角发出多见,但也可见直角和钝角发出者,经1～4级分支形成毛细血管网.基底节区内各核团和内囊微血管密度高低不等,其由高到低依次为壳核、尾状核、屏状核、杏仁核、苍白球、内囊.结论:基底神经节各核团内微动脉的走行迂曲、形态各异,可能是该区易发生出血的形态学基础.各核团间微血管密度的差异,说明各部神经细胞的需氧量和代谢的活跃程度不同.     

小脑皮质及髓质的微血管构筑

12例新鲜儿童尸脑,以甲醛碳素墨水灌注,光镜观察.小脑皮质及髓质的动脉来源于小脑动脉皮质支及中央支.血管多以直角及呈放射状穿小脑实质.小脑皮质及髓质的动脉分为皮质浅动脉、皮质中动脉、皮质深动脉、皮质髓质动脉及髓质动脉.动脉分支间相互吻合构成皮质浅、深层及髓质血管网.血管及血管网眼密度以皮质深层为最高.皮质的血供主要来自皮质浅、中、深动脉,髓质主要来自皮质髓质动脉及髓质动脉.髓质内的血管多呈直角分支.且血管走行与白质纤维方向一致.本文讨论了小脑皮质及髓质的血供及血管形态与小脑血管疾病的关系.     

利用内源性碱性磷酸酶显示组织中的微血管构筑

碱性磷酸酶常见于运输活跃的膜上,如毛细血管内皮,肾近曲小管刷状缘和肠上皮的纹状缘等。早期常用组织化学方法显示内源性磷酸酶．然而存在所需试剂较多、染色时间较长的缺点。在原位分子杂交实验中,常用碱性磷酸酶标记抗地高辛抗体,而采用硝基四氮唑蓝（４－ｎｉｔｒｏｂｌｕｅｔｅｔｒａｚｏｌｉｕｍｃｈｌｏｒｉｄｅ,ＮＢＴ）和５一溴－４－氯－３－吲哚基－磷酸（５－ｂｒｏｍｏ－４－ｃｈｌｏｒｏ－３－ｉｎｄｏｌｙｌ－ｐｈｏｓｏｈａｔｅ,ＢＣＩＰ）作为碱怀磷酸酶的显色剂（以下简称ＮＢＴ／ＢＣＩＰ显色系统）［１］．本文试…     

应用单宁酸-氯化铁法显示小脑不同部位的微血管构筑

目的　光镜下观察 6只大鼠小脑前叶、后叶及蚓部微血管构筑。方法　用单宁酸 -氯化铁法 (TAFM)媒染显示小脑内血管。结果　小脑各部位皮质、髓质动脉均来源于软脑膜动脉和小脑动脉中央支 ,软脑膜动脉分支多以直角进入小脑皮质 ,分别在分子层、蒲肯野细胞层、颗粒层形成毛细血管网 ;小脑后叶髓质中微动脉呈爪状分支 ,小叶两侧皮质深层微动脉或毛细血管可跨过髓质互相沟通。结论　 TAFM显示小脑微血管构筑清晰、立体感强 ,并发现小叶内皮质深层微血管之间有吻合支     

小脑齿状核及其静脉的磁敏感加权成像

目的利用磁敏感加权成像(SWI)技术显影齿状核及其静脉,探讨齿状核门位置与静脉变异的关系。方法筛选18～30周岁的健康青壮年51例(男24例,女27例)行3. 0T SWI序列头部扫描,利用最小密度投影(m IP)技术对原始图像进行后处理,通过SWI序列的原始图像以及重建后图像,对齿状核门及周围静脉的解剖形态进行观察分析。结果齿状核长(16. 64±0. 20)mm,宽(8. 36±0. 14)mm,两侧长宽均无差异;齿状核长轴夹角中位数为26. 80°(四分位间距为34. 58°)。齿状核静脉可分为外侧、内侧两组,由水平裂大静脉、核静脉、齿状核中央静脉及蚓静脉引流。齿状核外前部经核静脉引流至岩上窦;外中部由多条小静脉向外侧汇入水平裂大静脉;外后部由很多支极细小静脉引流,汇入蚓静脉或髓质静脉;内前部由蚓旁静脉、齿状核中央静脉共同引流,蚓旁静脉常于齿状核门周围汇入齿状核中央静脉,最终经蚓前静脉至直窦;内后部常汇入蚓静脉属支,蚓旁静脉可与之共同汇入蚓静脉。齿状核门75. 49%位于内上象限,24. 51%位于内下象限。结论齿状核及其静脉在SWI图像中清晰可见,齿状核门的位置可能与蚓旁静脉汇入点相关。     

小儿郎格罕细胞组织细胞增生症并发小脑齿状核变性1例

病例患儿，男，7岁，因左眼球突出4年伴右眼球突出、行走不稳1年入院。病后少语少动，无发热、皮疹、多饮、多尿。家族中无遗传病病人。体检：体温36.7℃，脉搏90次／分，行走慢且不稳，反应迟钝，双眼球突出，左眼甚（如图），无眼震，甲状腺不大，双膝腱反射弱，指鼻试验、跟-膝-胫试验阳性。T3、T4、TSH、基础代谢率、肝功能、骨髓象、血常规、尿比重均正常。胸片示双肺纹理重，颅骨平片见多个不规则骨破坏区，眼眶CT：眼球结构正常，眼外肌肥厚，颅底骨质破坏，其边界可见骨肥厚，头颅CT：小脑齿状核区对称性低密度影，无占位效庆，…     

杏仁核点燃癫癎鼠小脑齿状核和浦肯野细胞fos蛋白的表达

目的：探讨癫痫的病理生理机制。方法：采用免疫组化的方法，在杏仁核点燃的大鼠癫痫模型上，观察小脑齿状核和浦肯野细胞fos蛋白的表达情况。结果：在杏仁核点燃癫痫大鼠，不同发作级别其fos表达强度不同，Ⅰ～Ⅲ级发作时小脑齿状核和浦肯野细胞fos蛋白的表达为弱阳性核团；Ⅳ-Ⅴ级发作时小脑齿状核和浦肯野细胞fos蛋白的表达为强阳性核团。结论：小脑齿状核和浦肯野细胞极可能参与杏仁核点燃癫痫的病理生理过程。     

人鼻粘膜的微血管构筑

用新鲜胎儿和新鲜成人标本作墨汁灌注连续切片、冰冻切片碱性磷酸酶染色光镜观察和微血管铸型扫描电镜观察方法研究了人鼻粘膜的微血管构筑。鼻甲粘膜内微动脉吻合形成两级微动脉拱。微静脉吻合形成浅、深静脉丛、下鼻甲粘膜的深静脉丛是由短而卷曲的微静脉吻合而成的致密静脉丛。在中、下鼻甲粘膜内观察到动－静脉吻合。对粘膜内微血管构筑的机能意义进行了讨论。     

Synaptic pathology in the cerebellar dentate nucleus in chronic multiple sclerosis

In multiple sclerosis, cerebellar symptoms are associated with clinical impairment and an increased likelihood of progressive course. Cortical atrophy and synaptic dysfunction play a prominent role in cerebellar pathology and although the dentate nucleus is a predilection site for lesion development, structural synaptic changes in this region remain largely unexplored. Moreover, the mechanisms leading to synaptic dysfunction have not yet been investigated at an ultrastructural level in multiple sclerosis. Here, we report on synaptic changes of dentate nuclei in post‐mortem cerebella of 16 multiple sclerosis patients and eight controls at the histological level as well as an electron microscopy evaluation of afferent synapses of the cerebellar dentate and pontine nuclei of one multiple sclerosis patient and one control. We found a significant reduction of afferent dentate synapses in multiple sclerosis, irrespective of the presence of demyelination, and a close relationship between glial processes and dentate synapses. Ultrastructurally, we show autophagosomes containing degradation products of synaptic vesicles within dendrites, residual bodies within intact‐appearing axons and free postsynaptic densities opposed to astrocytic appendages. Our study demonstrates loss of dentate afferent synapses and provides, for the first time, ultrastructural evidence pointing towards neuron‐autonomous and neuroglia‐mediated mechanisms of synaptic degradation in chronic multiple sclerosis.     

Synaptic organization of the cerebello-thalamo-cerebral pathway in the cat. I. Projection of individual cerebellar nuclei to single pyramidal tract neurons in areas 4 and 6

The neural connections of the dentate (DN) and the interpositus (IN) nuclei to the motor cortex and area 6 were investigated by recording intracellular postsynaptic potentials from fast and slow pyramidal tract neurons (PTNs) in the anesthetized cat. Localized stimulation of DN and IN produced di- or polysynaptic EPSPs in fast and slow PTNs in the "forelimb area" of the motor cortex and area 6. The effects of stimulation of the two cerebellar projections were essentially the same, although some regional difference of their relative strength was noted. In these cortical areas, the majority of fast and slow PTNs received convergent inputs from both DN and IN. By examining the interaction of DN- and IN-evoked EPSPs, spatial facilitation and occlusion at the level of the thalamus were demonstrated. Therefore, it was concluded that at least a portion of the convergence of the dentate and the interpositus inputs occurred at the level of the ventrolateral nucleus of the thalamus.     

The human dentate nucleus: a complex shape untangled

The dentate nucleus is the largest single structure linking the cerebellum to the rest of the brain. The peculiar shape and large size of the human dentate nucleus have sparked a number of theories about the role of the cerebellum in human evolution. Some of the proposed ideas could be explored by comparative studies of humans and apes, but comparative studies are hindered because of the complex three dimensional shape of the human dentate. Here we present a 3D model based on a quantitative reconstruction of the human dentate; this model can facilitate comparative studies. The dentate nucleus has been partitioned into dorsal and ventral lamellae based on sheet thickness. Our data show that the thicker ventral lamella occupies a distinctly smaller portion of the human dentate than previously hypothesized. Within the dorsal lamella there is a medial to lateral increase in depth of dentate folds. However, the dorsal lamella retains a thin sheet thickness unlike the macrogyric ventral lamella, in which sheet thickness is increased. The appearance of larger folds laterally reflects the emergence of secondary folds that could encompass the projection of the cerebellar hemispheres, minimizing convergence of different corticonuclear microzones. Thus, the unique feature of the hominoid dentate is the development of a large surface area and an expansion of its mediolateral width. We propose that this is to allow for a large number of independent corticonuclear modules that can modulate an equal large number of sequential motor acts.     

Histamine evokes excitatory response of neurons in the cerebellar dentate nucleus via H2 receptors

Previous studies have shown an excitatory effect of histamine on neurons in two cerebellar nuclei, the fastigial nucleus and the interposed nucleus. Here we investigated action of histamine on the dentate nucleus (DN), another nucleus of the cerebellum, and provided more evidence for motor control by histamine via the cerebellum. Spontaneous unitary discharge of neurons in the DN was extracellularly recorded by use of cerebellar slice preparations. In total 79-recorded neurons, which were from 53 cerebellar slices, 67 neurons (84.8%) had an excitatory response to histamine stimulation, and the rest (15.2%) were not reactive. The histamine-induced excitation of the DN neurons was not blocked by low-Ca²⁺/high-Mg²⁺ medium, demonstrating that this effect of histamine was postsynaptic. Triprolidine, an antagonist of histamine H₁ receptors, did not block the excitatory effect of histamine, but ranitidine, an antagonist for H₂ receptors, blocked the excitatory response to histamine in a concentration-dependent manner. Further, histamine H₁ receptor agonist 2-pyridylethylamine did not elicit any response of DN neurons, but H₂ receptor agonist dimaprit had an excitatory action on the DN cells and this action was blocked by ranitidine. These results indicate that histamine excites cerebellar DN neurons via histamine H₂ receptors. Since the DN receives hypothalamocerebellar histaminergic projections and plays a role in initiation and planning of somatic movement, the postsynaptic excitation of the DN neurons by histamine suggests the possibility that the initiation and planning of movement may be modulated by the histaminergic projections.     

Cerebellar pleomorphic xanthoastrocytoma in an infant

Pleomorphic xanthoastrocytoma (PXA) is a rare brain tumor and typically occurs in the superficial cerebral hemispheres of young subjects. We report a case of PXA in the cerebellum of a 3-month-old infant in view of its unusual location and age. The patient presented with a 1-month history of upward eyeball gazing difficulty. To the authors' knowledge, this is the first report of occurrence of this neoplasm in the cerebellum of an infant. We report the morphologic and immunophenotypical features, and literature review with regard to the clinicopathologic aspects of a case of unusual PXA.     

Monolateral hypoplasia of the motor vagal nuclei in a case of sudden infant death syndrome

During the development of motor vagal nuclei (MVN), the neuroblasts of the myeloencephalic basal plate migrate in the dorsolateral direction to form the dorsal motor vagal nucleus (DMVN) and ventrolaterally to form the ventral motor vagal nucleus (VMVN). Those neuroblasts that remain close to the median sulcus will form the hypoglossal nucleus. In support of the congenital origin of the alteration of the MVN in sudden infant death syndrome (SIDS), we report the case of an 8‐month‐old female child who was found dead in her cot. The neuropathological assessment revealed that the medullary triangle of the 4th ventricle floor was asymmetric, owing to the presence of three prominences to the left side of the median sulcus. The medial prominence corresponded to the hypoglossal nucleus, which showed a marked increase in the number of large neurons; the intermediate prominence corresponded to the DMVN whose large neurons were reduced and were recognizable mainly at the level of the medial fringe; the lateral prominence corresponded to the solitary nucleus. The left solitary tract showed a reduction of the transverse diameter. Also, the left VMVN showed marked reduction in the number of neurons. Inflammatory and astrocytic reactions were absent. We suggest that in SIDS cases the hypocellularity of the MVN and the increased number of neurons of the hypoglossal nucleus are intimately related, indicating a congenital alteration due to incomplete migration of the vagal neuroblasts with abnormality of the autonomic cardio‐respiratory control.