Intracranial medulloblastoma as the cause of progressive ataxia in a 6-month-old draft horse cross gelding

We describe the unique clinical presentation of a central nervous system neoplasm in a 6-month-old draft horse cross gelding. Based on the neurologic examination at admission, neurolocalization was most consistent with a mildly asymmetric cervical, multifocal, or diffuse myelopathy. Mild vestibular involvement also was considered, but no cranial nerve deficits were observed. The gelding was negative for Sarcocystis neurona or Neospora hughesi based on paired serum and cerebrospinal fluid (CSF) samples analyzed, with no evidence of cervical compression based on contrast myelography. The horse was euthanized because of progression of clinical signs. At necropsy, a mass was identified associated with the cerebellum, and histopathology was consistent with medulloblastoma, which has not been reported previously in the horse.     

Recording cerebellar neuron activities in swimming goldfish

ABSTRACT:   Neuronal activities were investigated in the cerebellum of immobilized and swimming goldfish Carassius auratus . Extracellularly recorded neural activities of the cerebellum in immobilized goldfish were characterized and classified into five types. Based on the waveforms and recording depths, these five neural activity types were estimated to originate from three identified classes of cerebellar neurons: Purkinje cells, eurydendroid cells, and granule cells. Chronic recording of cerebellar neuron activities in unrestrained goldfish was performed for more than 100 h. During the chronic recordings, a submersible amplifier attached to the goldfish head, and a multielectrode array developed for the present study were used. Neuronal activities in the cerebellum of free-swimming fish could also be classified into five types as in the immobilized condition. Firing patterns of two neurons identified as Purkinje cells and eurydendroid cells were analyzed during turning movements of the goldfish. The firing patterns of these neurons changed in relation to turning movements. Although some improvements are required, the chronic recording method developed in the present study can be applied to further investigations concerning the direct relationship between brain neural activities and certain behavior.     

The Effect of Tryptophan on Serotonin-Like Neurons in Duck Cerebellum

Healthy Cherry Valley ducks were used in the present study. Different doses of tryptophan were injected intraperitoneally to them after being fasted 4 h （8：00 a.m.-12：00 a.m.）. One hour later, they were deeply anaesthetized and perfused. The cerebellum was removed to make serial paraffin longitudinal sections. The streptavidin-biotin-peroxidase complex （SABC） method was used to study the distribution of serotonin-like neurons in the cerebellum. All films were analysed by using a computer-assisted image analysis system. Serotonin-like neurons are only localized in cerebellar Purkinje cell layer. The optical density averages of serotonin-like neurons in 200 and 100 mg kg^-1 group are significantly higher than that of 0 mg kg^-1 group （P〈0.01）. These results show that serotonin-like neurons are distributed in Purkinje cell layer and that excessive tryptophan can affect the content of serotonin in cerebellum.     

乌鸡小脑的解剖学及神经肽Y神经元分布的研究

为了探明乌鸡小脑的形态结构及其细胞构筑和神经肽Y免疫反应神经元在小脑内的分布情况 ,采用石蜡切片HE染色和免疫组化SABC染色技术 ,对 1 0只泰和乌鸡的小脑进行了研究 ,并与北京鸭、肉鸽、本地鸡及非洲鸵鸟等禽类的相关结构进行了比较。结果表明 :①泰和乌鸡小脑皮质分 3层 ,由外至内依次为分子层、蒲肯野氏细胞层和颗粒层 ;②小脑分 1 0叶 ,Ⅰ、Ⅱ和Ⅹ为单叶 ,其余都有2个～ 3个小叶 ;③小脑中央核的神经元数量稀少 ;④神经肽Y免疫阳性神经元主要存在小脑皮质的蒲肯野氏细胞层 ,分子层、颗粒层 ,在小脑中央核未见阳性反应细胞 ;⑤泰和乌鸡小脑的形态结构及其细胞构筑与其它家禽相似 ;⑥小脑内NPY阳性神经元在蒲肯野氏细胞层的分布与鸡、肉鸽、大鼠的大体相似 ,在小脑白质内与肉鸽的有一定差异     

Brain anatomy of two-toed sloth (Choloepus didactylus,Linnaeus, 1758): A comparative gross anatomical study of extant xenarthrans

The neural system plays an important role in understanding some features of animals. Anatomical complexity correlates with the increase of functional capacity. Xenarthrans include anteaters (Vermilingua), armadillos (Cingulata) and sloths (Folivora). This group is the base of eutherian mammals, and understanding the anatomy of its neural system could provide data for functional and evolutionary interpretations. The gross anatomy of the xenarthran brain is recorded. Four extant families of Pilosa and two families of Cingulata were sampled. Usual dissection procedures were used, and the brains were analysed macroscopically. The brain of two-toed sloth, three-toed sloth, six-banded armadillo, giant anteater and collared anteater are gyrencephalic. Pygmy anteater, nine-banded armadillo, great long-nosed armadillo, southern naked-tailed armadillo and giant armadillo are lissencephalic. In most species, the rhinal fissure presents two segments, rostral and caudal (except in Vermilingua and three-toed sloth). The diencephalon and brainstem present similar anatomy. The cerebellum is wide and presents four lobes (rostral, central, caudal and floccular). Its average volume is 12.16% (Folivora), 14.26% (Vermilingua) and 18.61% (Cingulata). Among these groups, there is a statistical difference between Folivora/Cingulata concerning the cerebellum average. The general pattern of the brain of the xenarthrans is similar to that of other mammals.     

雌激素对大鼠小脑中Bcl-2和Bax蛋白表达的影响

采用免疫组织化学超敏SP法检测摘除卵巢及用外源性17β-雌二醇治疗后SD大鼠小脑中Bcl-2和Bax蛋白表达的变化.结果显示,摘除双侧卵巢后,SD大鼠小脑皮质及深层核团中Bcl-2的表达有不同程度的降低,而Bax的表达出现不同程度的上升;给予外源性17β-雌二醇治疗后,2种蛋白的比例基本恢复正常.表明,雌激素能够下调小脑皮层及小脑深层核团中Bax蛋白的表达,上调Bcl-2蛋白的表达,对小脑神经元具有保护作用.     

MAGNETIC RESONANCE IMAGING OF SPONGY DEGENERATION OF THE CENTRAL NERVOUS SYSTEM IN A LABRADOR RETRIEVER

A 7-month-old, neutered female Labrador Retriever was evaluated for tetraparesis and subtle cerebellar dysfunction. Clinical signs progressed over a period of 6 weeks to severe ataxia, hypermetria, intention tremors, and finally non-ambulatory tetraparesis. On magnetic resonance imaging of the brain there were large, bilaterally symmetrical, ovoid lesions in the region of the deep cerebellar nuclei that were hyperintense on T2-weighted and proton density images and hypointense on T1-weighted images. There were similar but smaller bilaterally symmetrical lesions present within the thalamus. Euthanasia was performed and lesions consistent with the previously described spongy degeneration of Labrador Retrievers were identified. This disease and its relation to similar human heritable leukodystrophies are discussed.     

山羊胚胎小脑皮质的形成和发育

对山羊胚胎小脑皮质形成及其神经元发育的形态学变化进行了研究。结果表明:(1)山羊胚胎小脑形成于第6周末,小脑皮质的外颗粒层、分子层首先形成。(2)发育过程中,山羊胚胎小脑的外颗粒层呈现出非常复杂的变化趋势:第7～10周外颗粒层达到一定厚度,第11～12周开始变薄,此后外颗粒层又开始变厚,直到第15～16周又变薄,17～18周再次增厚,此后再次变薄,直到出生前1周外颗粒层已经较薄,仅有4～5层细胞。(3)山羊胚胎的蒲肯野氏细胞可能在第8周以前就已聚集定位,第14周以后,蒲肯野氏细胞内部结构逐渐发育成熟,这说明蒲肯野氏细胞虽然发生较早,但其开始发育的时间较晚。     

Cerebellar cortical abiotrophy in Wiltshire sheep

AIM: To investigate the nature of a neurological disease in Wiltshire sheep.

METHODS: Three affected lambs were examined, humanely killed and necropsied. Selected neurological tissues were examined by light and electron microscopy.

RESULTS: Primary neurological lesions were confined to the cerebellum and were characterised by loss of Purkinje cells and the presence of large hypertrophied dendrites of surviving Purkinje cells. These contained stacks of smooth endoplasmic reticulum. There was hyperplasia and cell swelling of Bergmann glia. Mild Wallerian-type degeneration affected white matter in the cerebellum and spinal cord.

CONCLUSION: The cerebellar lesions were of a degenerative and reactive rather than hypoplastic nature. These, and the history, suggest a genetic cause with putative inheritance as an autosomal recessive trait. Accordingly, the disorder is described as a cerebellar abiotrophy.     

雌激素对大鼠小脑神经元生长发育的影响

    为了观察雌激素对离体培养神经元的生长发育及神经分泌的影响,取1日龄SD大鼠,对小脑神经细胞进行培养,通过补充17β-雌二醇观察神经细胞生长发育情况及运用免疫组织化学SP法研究雌激素受体(ER)、神经生长因子(NGF)和胆碱乙酰转移酶(ChAT)的表达变化结果表明,雌激素对体外培养小脑神经元的生长、发育影响显著,可促进胞体的生长、突起的伸长;延长培养神经元的存活时间,阻止神经元的退化、萎缩和死亡雌激素对体外培养小脑神经元的神经分泌功能影响显著,可促进培养神经元ER、NGF和ChAT的表达,显著增加ER、NGF和chAT阳性神经元的数量并呈现出培养时间依赖性的变化说明雌激素通过ER可直接或间接地作用于培养神经元,发挥神经营养和调控神经信息传递的作用