Lateral Mobility of the Cell Adhesion Molecule L1 Within the Surface Membrane of Morphologically Undifferentiated and Differentiated Neuroblastoma Cells

Lateral mobility and localization in the surface membrane of the adhesion molecule L1 was studied in morphologically undifferentiated and differentiated neuroblastoma cells to gain insight into its possible association with the different molecular forms of N-CAM. In undifferentiated cells, the fraction of mobile L1 molecules is high and similar to that of N-CAM 140. Upon long-term morphological differentiation, the fraction of mobile L1 molecules is reduced by a factor of three and is similar to that of N-CAM 180, the predominant molecular form of N-CAM in differentiated neuroblastoma cells. Comparable to N-CAM 180, L1 is also preferentially accumulated at contact sites between these cells as seen by indirect immunofluorescence. These observations raise the question of whether at least part of the L1 molecules may be directly or indirectly (e.g. via N-CAM 180) linked to the cytoskeleton, thus stabilizing cell contacts between differentiated cells.     

β1整合素基因缺失对Gi蛋白分布的影响

目的 了解跨膜蛋白β1整合素对信号分子G蛋白细胞内构型的影响,为进一步研究β1整合素在信号传导中的作用打下基础。方法 采用荧光双标记及重叠合显微镜分析技术,观察野生型胚胎干细胞系（D3细胞）,β1整合素基因敲除胚胎干细胞（G201细胞）,β1整合素基因敲除后再植入胚胎干细胞（G201N）及小鼠胚胎心肌细胞中多种G蛋白（Gas,Gai1-3,Gao,Gai/o/t/z）细胞内构型特点和差异。结果 Gas,Gao,Gai/o/t/z在上述几种细胞系中均呈弥温性分布,未能发现明显差异,与此不同的是Gai1-3在D3细胞源性心肌细胞内呈网状分布,在非心肌细胞内呈线条状分布,而在G201细胞中Gi上述特异性构型被打乱,呈近似于弥漫样分布,值得注意的是在β1整合素重新恢复的G201N细胞Gi构型又呈网样或线条样分布,与野生型胚胎干细胞中Gi的构型相一致。结论 β1整合素能够影响信号分子Gi蛋白的细胞内定位,推测β1整合素可通过改变Gi的分布而影响Gi介导的信号传导。     

神经细胞粘附分子在人脑星形细胞瘤中的表达

研究神经细胞粘附分子在人脑星形细胞瘤发生发展中的作用。方法：用原位杂交和免疫组织化学方法检测４０例人脑星形细胞瘤组织中的ＮＣＡＭｍＲＮＡ及其蛋白（ＣＤ５６）的表达。结果：星形细胞瘤１,２级中ＮＣＡＭｍＲＮＡ及蛋白的表达显著高于星形细胞瘤３,４级,核酸与蛋白水平的检测结论一致。结论：ＮＣＡＭｍＲＮＡ及其蛋白的表达与星形细胞瘤的恶性程度有关,ＮＣＡＭ的高表达可与星形细胞瘤的侵袭转有关,并有可能成为星形     

腹膜透析对可溶性细胞间粘附分子-1水平的影响及其意义

目的：探讨腹膜透析对可溶性细胞间粘附分子－１（ｓＩＣＡＭ－１）水平的影响及其在长期透析患者免疫功能下降中的作用。方法：采用夹心ＥＬＩＳＡ方法分别检测感染期、非感染期连续不卧床腹膜透析（ＣＡＰＤ）患者血清及腹膜透析液中ｓＩＣＡＭ－１水平的变化。结果：与非感染期ＣＡＰＤ患者相比,感染期ＣＡＰＤ患者血清ｓＩＣＡＭ－１水平显著降低,腹透液ｓＩＣＡＭ－１水平明显升高（Ｐ〈０．０１）;治疗后血清及腹透液ｓＩＣＡＭ－１水平,均较治疗前显著升高或降低（Ｐ〈０．０１）。结论：ｓＩＣＡＭ－１在感染期ＣＡＰＤ患者血清及腹透液中的变化,可能损害了巨噬细胞的正常粘附能力,从而降低机体的免疫能力。     

γ射线诱导人肝癌细胞表达B7-1共刺激分子的研究

目的　研究电离辐射与肿瘤细胞B7- 1分子表达之间的关系 ,探讨肿瘤细胞辐照后免疫原性增强的机制。方法　采用间接免疫荧光 -流式细胞仪分析技术 ,研究在用不同剂量γ射线照射SMMC - 772肝癌细胞后、培养不同时间内SMMC - 772细胞B7- 1共刺激分子的表达水平。并用3H -TdR释放法测定照射和未照射肿瘤细胞与淋巴细胞共反应后的细胞毒活性。结果　未照射和经 10、2 0、30Gy照射的人肝癌细胞不表达B7- 1分子。经 40、5 0、6 0Gy剂量照射后 ,SMMC - 772肝癌细胞表达B7- 1分子 ,最高达 6 6 .8± 1.3% ,与对照组比有非常显著性差异 (P <0 .0 1)。表达时间的高峰在照射后培养 72h时 ,最低在照射后培养 2 4h时 (P <0 .0 5 )。细胞毒活性测定结果表明 ,表达B7- 1分子的SMMC - 72肝癌细胞与淋巴细胞共反应后 ,细胞毒活性明显高于未照射组 (P <0 .0 1)。结论　γ射线可诱导肝癌细胞表达B7- 1分子 ,从而增强肿瘤细胞的免疫性     

Structure and evolution of neuronal wiring receptors and ligands

One of the fundamental properties of a neuronal circuit is the map of its connections. The cellular and developmental processes that allow for the growth of axons and dendrites, selection of synaptic targets, and formation of functional synapses use neuronal surface receptors and their interactions with other surface receptors, secreted ligands, and matrix molecules. Spatiotemporal regulation of the expression of these receptors and cues allows for specificity in the developmental pathways that wire stereotyped circuits. The families of molecules controlling axon guidance and synapse formation are generally conserved across animals, with some important exceptions, which have consequences for neuronal connectivity. Here, we summarize the distribution of such molecules across multiple taxa, with a focus on model organisms, evolutionary processes that led to the multitude of such molecules, and functional consequences for the diversification or loss of these receptors.     

动态血压正常高限者的左室肥厚

目的：观察动态血压为正常高限者的左室肥厚情况,为该患者群靶器官损害的防治策略提供依据。方法：根据２４小时动态血压监测结果将病人分为３组：Ｎ组（正常血压组）、ＮＨ组（血压正常高限组）和Ｈ组（高血压组）。以超声心动图检测左室舒张末期内径,舒张末期室间隔和左室后壁厚度等,计算左室重量指数（ＬＶＭＩ）。结果：Ｈ组（１２９±４１）和ＮＨ组（１１５±３２）的ＬＶＭＩ明显高于Ｎ组（９７±２３,Ｐ＝０．００００１和０．００５）,Ｈ组和ＮＨ组间无统计学差异。结论：动态血压正常高限者左室肥厚程度明显重于血压完全正常者。对该人群亦应积极采取措施预防和治疗靶器官损害     

LIF对体外培养小鼠孕早期胚胎发育及ICAM-1表达的影响

目的研究白血病抑制因子（ＬＩＦ）在胚胎发育中的作用并探讨其参与胚泡着床的机制。方法收集昆明种小鼠的单细胞受精卵,连续培养１２０ｈ,观察不同浓度ＬＩＦ对胚胎发育的影响;用免疫印迹法测定培养液中细胞间粘附分子（ＩＣＡＭ－１的表达水平。结果ＬＩＦ在０．１～１０ｎｇ／ｍｌ浓度之间对胚胎发育有促进作用,其作用在桑椹胚及胚泡期最明显（Ｐ＜０．０５）;ＬＩＦ增加胚胎ＩＣＡＭ－１的表达,其作用在０．１ｎｇ／ｍｌ浓度时最强,并随着浓度的增加而减弱。结论适应浓度的ＬＩＦ可促进胚胎发育,增加ＩＣＡＭ－１的表达,从而参与胚胎着床过程。