皮脂腺肿瘤p53及bcl-2蛋白表达的研究

目的研究ｐ５３及ｂｃｌ ２基因在皮脂腺肿瘤中的作用。方法应用免疫组化方法对皮脂腺良、恶性肿瘤上述两种基因产物的表达进行了检测。结果５例皮脂腺癌、２例皮脂腺痣和２例皮脂腺增生症均不同程度表达ｂｃｌ ２蛋白,而ｐ５３蛋白仅表达于５例皮脂腺癌的癌细胞。两种蛋白表达强度无相关关系（ｒ’ｓ＝０．１０５,Ｐ＞０．０５）。结论ｐ５３基因突变在皮脂腺癌发生中起决定性作用,而ｂｃｌ ２基因则起协同促进作用。检测ｐ５３蛋白可用于鉴别皮脂腺良、恶性肿瘤。     

厚朴酚对兔视网膜缺血再灌注神经元凋亡和bcl-2、caspase-3表达的影响

目的 研究厚朴酚(Magnolol,Mag)预处理对视网膜缺血再灌注损伤后神经元凋亡和bcl-2、caspase-3蛋白表达的影响,并探讨其对视网膜缺血保护的可能机制.方法 用升高眼压的方法制作兔视网膜缺血模型,将新西兰大白兔随机分为正常组、生理盐水组及Mag组.缺血前24h,对照组耳缘静脉注射生理盐水,Mag组注射厚朴酚100mg/kg.观察缺血再灌注后不同时间段对照组及Mag组视网膜组织学变化,TUNEL检测及bcl-2、caspase-3蛋白的表达.结果 视网膜缺血再灌注各时间段,HE染色Mag组大鼠视网膜内层厚度均较对照组厚,且内核层细胞数较多(P＜0.01); TUNEL法检测正常组无凋亡细胞,缺血再灌注24h凋亡达高峰,Mag组内核层的凋亡细胞比对照组少(P＜0.01);Mag组和对照组在缺血再灌注12h均检测到bcl-2、caspase-3蛋白表达,Mag组较生理盐水组少(P＜0.01).结论 Mag预处理可以促进视网膜缺血再灌注后细胞的存留,减少细胞凋亡,bcl-2、caspase-3蛋白表达的调节可能参与这种保护机制.     

鼻咽癌组织中bcl-2、bax和p53的表达及其与瘤细胞凋亡的关系

目的：了解鼻咽癌组织中瘤细胞ｂｃｌ２、ｂａｘ和ｐ５３的表达及其与瘤细胞凋亡指数（ａｐｏｐｔｏｓｉｓｉｎｄｅｘ,ＡＩ）的关系。方法：对３８例未经治疗的鼻咽癌组织,应用免疫组化ＬＳＡＢ法检测瘤细胞ｂｃｌ２、ｂａｘ和ｐ５３的表达;末端标记细胞死亡检测法（ＴＵＮＥＬ）计算癌细胞的凋亡指数。结果：（１）３７例（９７４％）中有９０％左右的瘤细胞呈ｂｃｌ２过表达;（２）３８例（１００％）中有７０％左右的瘤细胞过表达ｂａｘ;（３）２９例（７６３％）呈ｐ５３过表达;（４）３８例活检组织的平均ＡＩ为２６０２±２６４２／ＨＰＦ;（５）ＡＩ与ｂｃｌ２、ｂａｘ和ｐ５３的表达无相关性。结论：（１）本组大多数鼻咽癌组织的绝大部分瘤细胞均呈ｂｃｌ２和ｂａｘ高表达;（２）由于ｂｃｌ２和ｂａｘ的表达已在高水平达到相对平衡,因此在大多数人体鼻咽癌中它们可能并不起到介导瘤细胞凋亡的主导作用;（３）鼻咽癌组织中过表达的ｐ５３蛋白可能已失去了调节ｂｃｌ２和ｂａｘ的表达进而影响细胞凋亡的功能。     

bcl—2基因表达在慢性粒细胞白血病急变中的意义

目的探讨ｂｃｌ２基因表达在慢性粒细胞白血病（ＣＭＬ）急变中的生物学意义。方法采用碱性磷酸酶抗碱性磷酸酶免疫复合物方法和地高辛标记探针原位杂交技术检测各期ＣＭＬ患者６０例新鲜骨髓标本中ＢＣＬ２蛋白和ｂｃｌ２ｍＲＮＡ的表达,并对其中１９例标本进行流式细胞术分析骨髓细胞凋亡率及细胞周期。结果初诊和治疗后ＣＭＬ中ｂｃｌ２基因表达相近,但明显低于急变时。ｂｃｌ２ｍＲＮＡ表达与蛋白表达基本一致。ｂｃｌ２基因高表达与ＣＭＬ患者外周血血红蛋白、血小板、幼稚细胞及骨髓不成熟细胞比例相关。加速／急变期ＣＭＬ细胞凋亡率明显低于慢性期,但细胞周期无明显变化。结论ＣＭＬ急变时ｂｃｌ２基因表达增高,骨髓细胞凋亡率降低,这些现象部分地阐明了ＣＭＬ急变预后不良的机制,也为ＣＭＬ急变的早期诊断和治疗提供了实验依据。     

胰腺癌中bcl-2的表达与细胞凋亡及癌基因c-myc表达的关系

目的：探讨人胰腺癌中bcl-2的变化情况与细胞凋亡及c-myc表达的关系。方法：采用免疫组织化学（SP法）和分子原位杂交法检测bcl-2及c-myc在胰腺癌病人癌组织（50例）和胰腺癌转移灶组织（15例）中的表达。采用TUNEL法检测细胞凋亡。结果：细胞凋亡的变化规律与胰腺癌的发生发展和临床病理特征有着内在联系。在mRNA和蛋白水平上bcl-2基因和c-myc基因分布一致。bcl-2蛋白的表达影响胰腺癌中细胞凋亡,并与c-myc蛋白在胰腺癌和胰腺癌转移灶组中的表达协同关系。结论：bcl-2和c-myc基因在胰腺癌发生和发展过程中发挥着重要作用。     

Determinants of the exclusion zone in dopaminergic amacrine cell mosaics

A fundamental organizing feature of the retina is the presence of regularly spaced distributions of neurons, yet we have little knowledge of how this patterning emerges during development. Among these retinal mosaics, the spatial organization of the dopaminergic amacrine cells is unique: using nearest-neighbor and Vornoi domain analysis, we found that the dopaminergic amacrine cells were neither randomly distributed, nor did they achieve the regularity documented for other retinal cell types. Autocorrelation analysis revealed the presence of an exclusion zone surrounding individual dopaminergic amacrine cells and modeling studies confirmed this organization, as the mosaic could be simulated by a minimal distance spacing rule defined by a broad set of parameters. Experimental studies determined the relative contributions of tangential dispersion, fate determination, and cell death in the establishment of this exclusion zone. Clonal boundary analysis and simulations of proximity-driven movement discount tangential dispersion, while data from bcl-2 overexpressing mice rule out feedback-inhibitory fate-deterministic accounts. Cell death, by contrast, appears to eliminate dopaminergic amacrine cells that are within close proximity, thereby establishing the exclusion zone surrounding individual cells and in turn creating their mosaic regularity.     

Catecholamine-induced oligodendrocyte cell death in culture is developmentally regulated and involves free radical generation and differential activation of caspase-3

Oligodendrocyte cultures were used to study the toxic effects of catecholamines. Our results showed that catecholamine-induced toxicity was dependent on the dose of dopamine or norepinephrine used and on the developmental stage of the cultures, with oligodendrocyte progenitors being more vulnerable. A role for oxidative stress and apoptosis on the mechanism of action of catecholamines on oligodendrocyte cell death was next assessed. Catecholamines caused a reduction in intracellular glutathione levels, an accumulation in reactive oxygen species and in heme oxygenase-1, the 32 kDa stress-induced protein. All these changes were prevented by N-acetyl-L-cysteine, a thiocompound with antioxidant activity and a precursor of glutathione, and were more pronounced in progenitors than mature cells, which could contribute to their higher susceptibility. Apoptotic cell death, as assessed by activation of caspase-9 and -3 and cleavage of poly(ADP-ribose) polymerase (a substrate of caspase-3), was only observed in oligodendrocyte progenitors. Pretreatment with zVAD, a general caspase inhibitor, prevented activation of caspase-9 and -3, DNA fragmentation, and decreased progenitors cell death. Furthermore, the expression levels of procaspase-3 and the ratio of the proapoptotic protein bax to antiapoptotic protein bcl-xl were several folds higher in immature than mature oligodendrocytes. Taken together, these results strongly suggest that the catecholamine-induced cytotoxicity in oligodendrocytes is developmentally regulated, mediated by oxidative stress, and have characteristics of apoptosis in progenitor cells.     

联合应用神经保护剂对大鼠局灶性脑缺血后bcl-2表达的影响

目的：探讨不同类型神经保护剂联合应用是否较单一神经保护剂对局灶性脑缺血有更好的保护作用。方法：采用线栓法制作大鼠大脑中动脉闭塞模型（MCAO）,并分为1,6－二磷酸果糖（FDP）组、MK－801组、N－乙酰半胱氨酸（NAC）组,联合治疗组和对照组,应用western印记技术观察缺血后6和24h抗凋亡蛋白bcl-2表达的变化,结果：缺血后6h和24h,联合治疗组bcl-2表达明显增加,与单一用药各组相比有显性差异。结论：神经保护剂联合应用对大鼠脑组织缺血的保护作用较单一用药各组明显增强。     

类胡萝卜素对人乳腺癌细胞增殖及bcl-2基因表达的影响

目的 观察类胡萝卜素对人乳腺癌MCF－7细胞存活率、细胞周期和凋亡,以及对凋亡相关基因bcl－2的影响。方法 用MTT检测类胡萝卜素对MCF－7细胞作用的时间效应和剂量效应;流式细胞仪观察类胡萝卜素处理人乳腺癌细胞后细胞周期以及细胞凋亡的改变。用RT－PCR检测凋亡相关基因bcl－2的变化。结果 6种结构不同的类胡萝卜素对MCF－7乳腺癌细胞展现出不同的增殖抑制效果,60μmol／L的β－胡萝卡素和番茄红素在第4天的抑制率分别为88．4％和87．8％,而玉米黄素、角黄素、虾青素和玉米黄素双棕榈酸酯的抑制作用较弱。类胡萝卜素并不诱导87．8％,而玉米黄素、角黄素、虾青素和玉米黄毒素双棕榈酸酯的抑制作用较弱。类胡萝卜素并不诱导MCF－7细胞凋亡,番茄红素可阻滞细胞周期于G1／M,玉米黄素双棕榈酸酯可阻滞细胞周期于G0／G1期,而其他类胡萝卡素并不影响细胞周期。类胡萝卜素可不同程度地下调凋亡相关基因bcl－2mRNA的表达,bcl－2基因的下调与类胡萝卜素的抑制作用呈较明显的相关性。结论 类胡萝卜素可直接抑制人乳腺癌细胞MCF－7的增殖,不同结构的类胡萝卜素可能具有不同的抑制机制。     

咳喘灵对实验性豚鼠哮喘模型支气管——肺泡灌洗液嗜酸细胞Fas-mRNA及bcl2-mRNA表达的影响

研究咳喘灵对实验性豚鼠哮喘模型支气管—肺泡灌洗液嗜酸细胞凋亡基因Fas-mRNA及bc l2-mRNA表达的影响。方法:按文献造模,将豚鼠随机分哮喘模型组、强的松组、中药组、空白对照组。用原位杂交法检测治疗前后各组豚鼠支气管—肺泡灌洗液嗜酸细胞Fas-mRNA、bc l2-mRNA的表达,用HPIAS-1000彩色病理图文分析系统进行分析。全部数据使用SPSS10.0统计软件进行统计学处理。结果:中药组与强的松组均较空白对照组及哮喘模型组豚鼠支气管—肺泡灌洗液嗜酸细胞Fas-mRNA表达显著增多;bc l2-mRNA表达显著减少,P<0.05;中药组较强的松组Fas-mRNA表达显著增多,P<0.05。