N-乙酰半胱氨酸对慢性间歇缺氧大鼠海马神经元凋亡及氧化应激的影响

目的：探讨N-乙酰半胱氨酸(NAC)对慢性间歇缺氧(CIH)模型大鼠海马组织氧化应激及海马神经元凋亡的影响。方法:30只雄性Wistar大鼠随机分为慢性缺氧组、NAC治疗组及正常对照组3组，每组10只。采用化学比色法测定海马组织丙二醛(MDA)、超氧化物歧化酶(SOD)水平，同时应用免疫组化方法检测海马CA1 区磷酸化JNK(p-JNK)表达水平，应用TUNEL法检测海马CA1区神经元凋亡率。结果:NAC治疗组 MDA水平低于CIH组（1.71±0.43 vs 1.37±0.26，P＜0.05）、SOD活性高于CIH组（44.94±14.01 vs 57.66±14.07，P＜0.05），p-JNK表达水平低于CIH组 （0.53±0.10 vs 0.39±0.16，P＜0.05），海马神经元凋亡率显著低于CIH组（0.32±0.18 vs 0.20±0.11，P＜0.05）。结论:NAC能抑制慢性间歇缺氧导致的氧化应激，从而影响JNK信号转导通路，减少海马神经元凋亡。     

基因芯片对大鼠肝移植急性排斥反应T淋巴细胞信号传导基因表达变化的研究

目的：从基因水平研究肝移植急性排斥反应中T淋巴细胞信号传导途径。方法：利用4096条大鼠cDNA克隆的基因芯片对从急性排斥组Wistar→SD(n=5)和对照组SD→SD(n=5)两组肝移植大鼠T细胞中抽提、纯化mRNA，扩增、逆转录成cDNA，荧光标记后与芯片杂交，扫描后筛选出差异表达的基因。结果：在4096个基因中共发现差异表达基因190条，其中ll条与细胞信号传导有关的基因差异表达明显：MHC(3条)、CD3抗原(1条)相关基因；蛋白酶类：蛋白激酶C结合蛋白、蛋白酪氨酸磷酸酯酶D型受体、磷脂酰肌醇二磷酸酶基因各l条；涉及核酸信号传导、激活、转录、翻译的基因3条。结论：T细胞在肝移植术后排斥反应中信号传导机制涉及多个基因，基因芯片技术的大规模筛选为进一步研究T细胞在排斥反应中的信号传导途径提供了客观依据和目标。     

Protein kinase mediators of integrin signal transduction

 Protein kinases are important mediators of signal transduction initiated by soluble growth factors and cytokines. Cellular interactions with the extracellular matrix are mediated largely by members of the integrin class of cell adhesion molecules, which also subsume signal transduction functions required for cell growth, differentiation, and survival. Here we review the involvement of protein kinases in mediating integrin intracellular signal transduction and the possible role for these molecules in regulating integrin adhesion. Although in most cases mechanistic details are incomplete, the emerging theme of protein kinases mediating cross-talk between growth factor receptor and integrin signalling systems provides a timely backdrop against which to present new developments in this area. The contribution of the actin cytoskeleton to integrin signal transduction is discussed, with respect to the concept of ’solid-state’ signalling providing a mechanism for imposing order on the protein-protein interactions which underlie signal discrimination. Moreover, we review evidence that dysregulated integrin signalling contributes to pathological processes including arthritis, thrombasthenia, leucocyte adhesion deficiencies, and tumour angiogenesis and invasion. Received: 14 May 1996 / Accepted: 2 July 1996     

Detection and analysis of gastrointestinal sounds in normal and small bowel obstructed rats

This study is aimed at detecting gastrointestinal sounds (GIS) and correlating their characteristics with gastrointestinal (GI) conditions. The central hypotheses are that GIS generation depends on the motility patterns and the mechanical properties of the gut, and that changes in those result in measurable differences in GIS. An animal model which included both healthy rats and those with small bowel obstruction (SBO) was developed. The acoustic bursts, of GIS were detected by amplitude thresholding the signal envelope. Three methods of envelope estimation were proposed and evaluated. Envelope estimation using a Hilbert transform was found to produce the best results in the current application. The duration and dominant frequency of each detected GIS event was estimated and clear differences between healthy and diseased rats were discovered. In the control state, GIS events were found to consistently be of relatively short duration (3–65ms). Although the majority of events in the SBO state had similar short duration, infrequent longer events were also detected and appeared to be pathognomonic. Long duration events (>100 ms) occurred in each of seven obstructed, but in none of 14 non-obstructed, cases (p<0.001). It is concluded that GIS analysis may prove useful in the non-invasive, rapid, and accurate diagnosis of SBO.     

钙离子载体在诱导人外周血单核细胞分化为树突状细胞中的作用

目的研究钙离子载体(CI)能否诱导人外周血单核细胞(PBMC)分化为树突状细胞(DC)，并初步探讨其信号转导途径。方法分离健康献血者的PBMC，在体外用CI(A23187)或人重组粒细胞／巨噬细胞集落刺激因子(rhGM—CSF)和CI培养40h，或rhGM-CSF和白细胞介素4(IL-4)培养7d，部分PBMC预先用W-7或CsA或K35926处理30min后，再加入上述细胞因子或CI。相差显微镜下观察细胞形态，流式细胞仪检测细胞表面CD14、CD80、CD86、CD83等分子的表达，MTT比色法检测其对同种异体混合T淋巴细胞的刺激增殖作用。结果健康献血者的PBMC经CI培养40h，或rhGM—CSF与CI培养40h，或rhGM-CSF与IL-4培养7d，均可获得DC的典型形态和表面分子的表达，包括CD14表达下调、共刺激分子(CD80、CD86)表达上调，以及较强刺激同种异体混合T淋巴细胞增殖的作用；CI诱导的DC其CD14分子的下调及CD83分子的上调更明显，刺激混合T淋巴细胞的增殖能力更强；rhGM-CSF可协同CI诱导PBMC向DC的分化。经rhGM—CSF及CI处理的PBMC，其形态、表面标志物及对T细胞的刺激增殖能力，均受到W-7或CsA或KT5926不同程度的抑制；而rhGM-CSF及IL-4所诱导的PBMC其形态、表面分子的表达以及刺激T细胞增殖的作用却不受上述抑制剂的影响。结论CI可快速诱导PBMC向DC分化，其分化过程可能受控于Ca^2 /钙调蛋白及其下游的多个细胞信号转导途径的调节。     

Recurrent wavefront morphologies: A method for quantifying the complexity of epicardial activation patterns

We have developed a method for quantifying the complexity of activation patterns observed during ventricular fibrillation (VF) that is based on our previously reported methodology for decomposing epicardial mapping data into a set of isolated wavefronts. One-half second datasets are acquired from a 21×24 array of unipolar electrodes (1 mm spacing), and the wavefronts are isolated. A correlation technique is used to compute the similarity between all possible pairs of the isolated wavefronts. From these data, the wavefronts are sorted into clusters, each of which represents a recurring wavefront morphology. We define multiplicity (M) as the number of clusters needed to account for 90% of the total activations in the VF episode.M measures the complexity of the rhythm. In repetitive patterns (e.g., sinus rhythm),M=1, indicating that the same morphology repeatedly activates the mapped region. Typically, in VF,M>1, with larger numbers representing more complex, disorganized patterns. As an example, we computedM at 5, 10, 15, and 20 sec after electrical induction of VF in six pigs.M decreased significantly (p<0.001), suggesting increasing organization during this period.     

Investigation and improved performance of optical fibre probes in laser Doppler blood flow measurement

Laser Doppler flowmetry with optical-fibre beam transmission is a sensitive fast and convenient method of measuring tissue blood flow. However, its sensitivity can also be a problem because of movement artefacts. This study applies some basic considerations of fibre optics and Rayleigh light scattering to the field of laser Doppler blood flow meters. Practical suggestions are given by which movement arterfacts can be reduced by choice of optical fibres, attention to probe geometry, cladding the fibres to reduce their movements and in the method of application. Experiments which test the normalisation circuitry of laser Doppler instruments are described and the effects of movement artefacts on the interpretation of the pulsatile component of laser Doppler records are also discussed. Probe and fibre line movements cause high-frequency intensity fluctuations due to speckle movement. The intensity fluctuations produce an apparent Doppler shift much greater than the Doppler shift produced by the relative movements of probe and tissue. It has been found that it is important to ensure that the fields of view of the illuminating and detecting fibres do not overlap at the skin surface and that probe contact with the skin surface should be maintained.     

银杏叶提取物诱导大鼠主动脉平滑肌细胞HO-1的表达及细胞信号通路研究

目的： 旨在研究银杏叶提取物（Ginkgo Biloba Extract,EGB761）对大鼠主动脉平滑肌细胞(RVSMC)血红素氧合酶-1（HO-1）蛋白的影响,并探讨其中涉及的细胞信号通路。方法: 大鼠主动脉平滑肌细胞株复苏、传代培养到第6代，再复孔培养用于实验，分别给予空白对照、单纯EGB761、EGB761＋锌原卟啉Ⅸ(ZnPPⅨ)或不同的细胞内信号途径特异性阻断剂进行处理，采用Western blotting法定量检测HO-1蛋白表达。结果: EGB761能呈剂量依赖性诱导HO-1蛋白表达，加用ZnPPⅨ（血红素氧合酶特异性阻断剂）及酪氨酸蛋白激酶(TPK)阻断剂木黄酮均能显著抑制EGB761诱导的HO-1蛋白表达（均P<0.01），但calphostin-C（蛋白激酶C阻断剂）、LY294002（磷脂酰肌醇-3激酶阻断剂）及Bay11-7082（核因子-κB阻断剂）对EGB761诱导的HO-1蛋白表达无明显影响（均P>0.05）。结论: (1) EGB761能显著诱导RVSMC中HO-1蛋白的表达，并且这种诱导作用能被血红素氧合酶的特异性阻断剂ZnPPⅨ所阻断。（2）EGB761通过TPK途径介导大鼠主动脉平滑肌细胞HO-1蛋白的表达。     

肺动脉高压大鼠一氧化氮及过氧化氢依赖的可溶性鸟苷酸环化酶通路的变化

目的：观察低O2高CO2对血浆一氧化氮（NO）、肺组织超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、可溶性鸟苷酸环化酶(sGC)活性以及cGMP含量的变化，探讨NO-sGC和H2O2-sGC通路于肺动脉高压中的作用。 方法： 复制低O2高CO2 1、2、4周组及对照组大鼠模型。测定平均肺动脉压（mPAP）。比色法测定血浆一氧化氮（NO）、肺组织超氧化物歧化酶（SOD）、过氧化氢酶（CAT）活性，酶动力学分析基础及过氧化氢（H2O2）及硝普钠（SNP）激活的肺组织sGC酶活性，［125I］-放射免疫法检测肺组织cGMP含量。 结果： 低O2高CO2 1、2、4周组mPAP均明显高于对照组（均P<0.01）；血浆NO、肺组织SOD、CAT活性、基础sGC活性、过氧化氢（H2O2）及硝普钠（SNP）激活的sGC活性和肺组织cGMP含量均显著低于对照组（分别P<0.05, P<0.01）。 结论： 低O2高CO2抑制NO-sGC和H2O2-sGC通路参与肺动脉高压的形成与发展。