树鼩皮层局部脑缺血时海马细胞微环境及氨基酸含量动态变化的研究

目的：揭示血栓性脑缺血后，海马神经细胞微环境及其细胞外液兴奋性与抑制性氨基酸含量的动态变化，并探讨其相互关系及可能的机制。方法: 建立光化学反应诱导树鼩局部脑缺血模型，进行微灌流并收集海马细胞外液，用高效液相色谱-PITC衍生法和IL-1306型血气分析仪分别测量天冬氨酸（Asp）、谷氨酸（Glu）、甘氨酸（Gly）和γ-氨基丁酸（GABA）含量和微环境相关指标pH值、PCO2、PO2和HCO3－的变化。结果: 局部脑缺血后，海马细胞外液中上述各种氨基酸的含量与对照组比均升高（P<0.01）；pH值、PO2、HCO3－均下降（P<0.01）；PCO2在6 h升高（P<0.05）。结论: 局部脑缺血后海马细胞外液氨基酸平衡紊乱参与了脑损伤的发生，氨基酸的代谢改变与缺血后细胞微环境的变化有关。     

用cDNA阵列技术研究黄曲霉毒素B1诱发树鼩肝癌形成过程中的基因变化

目的 对树鼩肝癌形成过程中的基因表达差异进行动态分析,探讨肝癌发生的分子机制。 方法用cDNA阵列技术,将2例黄曲霉毒素B1诱发的树鼩肝癌组织分别与其癌旁组织和其肝癌形成前的活检肝组织、实验前对照和同期对照肝组织进行基因表达水平的6种比较分析。结果 不同的比较方式所显示的差异表达的基因谱不同,可归为4类:癌组织表达高于癌旁组织、癌旁组织表达高于癌发生前肝的组织;癌与癌旁表达水平相仿,但高于癌发生前的肝组织;癌组织下调,低于癌旁组织;癌发生前表达上调,在癌发生后表达下调。 结论 对肝癌形成过程中不同时期的肝组织基因表达水平进行动态对比分析,有助于阐明肝癌发生的分子机制并最终筛选出与肝癌发生有关的关键基因。     

酒精对树鼩感染乙型肝炎病毒的影响

目的：验证酒精对树鼠句感染ＨＢＶ（ｈｅｐａｔｉｔｉｓＢｖｉｒｕｓ）是否具有更高的易感性。方法：应用酒精性免疫抑制的树鼠句模型,观察酒精性免疫抑制树鼠句对ＨＢＶ的易感性。结果：酒精组树鼠句的肺泡巨噬细胞和外周血中性粒细胞的吞噬率明显低于对照组,白细胞移动指数明显高于对照组,ＨＢＶ感染率比对照组增高２５倍。结论：提示酒精组树鼠句在发生免疫功能明显受损的同时对ＨＢＶ易感性也显著增高。     

Laminar organization of receptive field properties in the dorsal lateral geniculate nucleus of the tree shrew (Tupaiaglis belangeri)

A laminar analysis of the receptive field properties of relay cells in the binocular region of the tree shrew dorsal lateral geniculate nucleus (LGN) found three main subdivisions. Lamina 1 (receiving ipsilateral eye input) and lamina 2 (contralateral) comprise a pair of layers that contain only ON-center neurons. Laminae 4 (contralateral) and 5 (ipsilateral) comprise a pair of layers with mostly OFF-center cells (86%). Laminae 3 and 6 (both contralaterally innervated) also form a distinct pair, although lamina 3 contains a mixture of cells with ON-centers (43%) or OFF-centers (57%), and lamina 6 contains mostly cells with ON-OFF centers and suppressive surrounds (81%). Cells located in the interlaminar zones resembled neurons in laminae 3 and 6. In comparison with the cells in the OFF-center laminae 4 and 5, the ON-center cells in laminae 1 and 2 had smaller, more elliptical receptive field centers with stronger responses to flashed visual stimuli. In addition, cells in the ipsilateral eye laminae 1 and 5 showed a greater change in center diameter, with eccentricity from the area centralis, than cells in the contralateral eye laminae 2 and 4. Principal components analysis using six receptive field properties (latency to optic chiasm stimulation, receptive field center diameter, maintained discharge rate, response onset latency, peak spike density, and phasic-tonic index) suggested that the cells in laminae 3 and 6 and the interlaminar zones are W-like. Principal components analysis of the same receptive field properties in laminae 1, 2, 4, and 5 did not reveal differences clearly related to X-like (parvocellular) and Y-like (magnocellular) categories. Ninety-seven percent of the cells tested for linearity of spatial summation in laminae 1, 2, 4, and 5 were linear. We conclude that the dominant organizational features of the tree shrew LGN are the ON-center, OFF-mter, and W pairs of layers that project to different regions within the striate cortex. © 1995 Wiley-Liss, Inc.