TRAF2 K48聚泛素化位点的研究

目的筛选K48聚泛素链在肿瘤坏死因子受体相关因子2（tumor necrosis factor receptor-associated facto r 2,T RA F2）上的主要修饰位点。方法比较不同物种间的T RA F2氨基酸序列,选出人T RA F2上保守率在90%以上的赖氨酸。构建人野生型TRAF2的表达载体及保守赖氨酸突变为精氨酸的突变表达载体。将不同的TRAF2表达载体与NF-κB荧光素酶报告基因表达载体共转至293FT细胞中,通过荧光素酶检测NF-κB激活情况。结果人TRAF2上共有8个保守率在90%以上的赖氨酸,酶切及测序结果证明本研究成功构建TRAF2野生型和突变型表达载体。NF-κB荧光素酶报告基因检测证明TRAF2-K320可能是K48聚泛素链的主要修饰位点。结论 TRAF2-K320位点对TRAF2介导的NF-κB激活具有负向调控作用。     

Chemoprevention of liver cancer by plant polyphenols

Primary liver cancer or hepatocellular carcinoma (HCC) is one of the most frequent tumors representing the fifth commonest malignancy worldwide and the third cause of mortality from cancer. Currently, the treatments for HCC are not so effective and new strategies are needed for its fight. Chemoprevention, the use of natural or synthetic chemical agents to reverse, suppress or prevent carcinogenesis is considered an important way for confronting HCC. Many of the chemopreventive agents are phytochemicals, namely non-nutritive plant chemicals with protective or disease preventive properties. In this review, we focus on plant polyphenols, one of the most important classes of phytochemicals, their chemopreventive properties against HCC and discuss the molecular mechanisms accounting for this activity.     

Interaction between the biological effects of high- and low-LET radiation dose components in a mixed field exposure

Abstract

Purpose: The relative biological effectiveness of two epithermal neutron sources, a reactor based source at Studsvik, Sweden, and a proton accelerator-based source in Birmingham, UK, was studied in relation to the proportional absorbed dose distribution as a function of neutron energy. Evidence for any interactions between the effects of biological damage induced by high- and low-linear energy transfer (LET) dose components, in this ‘mixed field’ irradiation, was also examined

Materials and methods: Clonogenic survival in Chinese Hamster-derived V79 cells was used to assess biological effectiveness in this study. Cells were irradiated in suspension at 4°C at depths of 20, 35, 50 and 65 mm in a water phantom. This prevented the repair of sublethal damage, predominantly that produced by both incident and induced γ-rays in the field, over the variable periods of exposure required to irradiate cells with the same total absorbed dose. Cell survival, as a function of the absorbed radiation dose and depth in the phantom, was compared with Monte Carlo N-Particle (MCNP) calculations of the proportional absorbed dose distribution as a function of neutron energy for the two sources.

Results: In terms of the dose-related reduction in clonogenic cell survival, the epithermal neutron source at Studsvik was more biologically effective than the Birmingham source at all depths considered in the phantom. Although the contribution from the high-LET dose component was greater for the Studsvik source at 20 mm depth in the phantom, at greater depths the dose contribution from the high-LET dose component at Studsvik overlap with those for the Birmingham source. However, the most striking difference is in the fast neutron component to the dose of the two sources, neutron energies > 1 MeV were only associated with the Studsvik source. The relative biological effectiveness (RBE) of both sources declined slightly with depth in the phantom, as the total high-LET dose component declined. The maximum source RBE for Studsvik was 2.70 ± 0.50 at 20 mm; reduced to 2.10 ± 0.35 at depths of 50 and 65 mm. The corresponding values for Birmingham were 1.68 ± 0.25 and 1.31 ± 0.19, all values relate only to the surviving fraction of V79 cells at 37%, since RBE values are only applicable to the selected endpoint. Based on a dose reduction factor (DRF) of 1.0 for the total low-LET component to the absorbed dose, the RBE values for the high-LET dose component (fast neutrons and induced protons from the nitrogen capture reaction) was 14.5 and 7.05 for the Studsvik and Birmingham neutron sources, respectively. This is well outside the range of RBE historically reported values for V79 cells for the same level of cell survival for fast neutrons. The calculation of RBE values, based on the proportional absorbed dose distribution as a function of neutron energy, from historical data, and using a RBE of 1.8 for the dose from the nitrogen capture reaction, suggests RBE values for the total high-LET dose component of 3.1–2.8 and 2.5–2.0 for Studsvik and Birmingham, respectively, values again declining with depth in the phantom.

Conclusions: The overall biological effectiveness of the mixed field irradiation from an epithermal neutron sources depends on the composition and quality of the different dose components. The experimentally derived RBE values for the total high-LET dose components in these ‘mixed field’ irradiations are well in excess of historical data for fast neutrons. The difference between the historically expected and the observed RBE values is attributed to the interactions between the damage produced by high- and low-LET radiation.     

核因子-κB p65在宫颈癌组织中的表达及意义

 目的　探讨NF κBp6 5蛋白在宫颈鳞癌及宫颈腺癌组织中表达的意义。 方法　采用免疫组织化学方法 ,用NF κBp6 5单克隆抗体检测 6 4例宫颈鳞癌组织 ,6例宫颈腺癌组织 ,11例宫颈上皮内瘤样病变 (CIN)组织 ,16例慢性宫颈炎组织中NF κBp6 5的表达。 结果　NF κBp6 5在宫颈鳞癌和腺癌中的阳性表达明显高于CIN和慢性宫颈炎组织 ,有淋巴转移的癌组织中NF κBp6 5的阳性表达率高于无淋巴转移的癌组织。结论　NF κBp6 5蛋白在宫颈癌的发生发展中起重要作用     

Preoperative glucocorticoids decrease pulmonary hypertension in piglets after cardiopulmonary bypass and circulatory arrest

BACKGROUND: Glucocorticoids during cardiopulmonary bypass benefit pediatric patients undergoing repair of congenital heart defects and are routine therapy, but underlying mechanisms have not been fully examined. The hypothesis was that glucocorticoids could improve cardiopulmonary recovery after cardiopulmonary bypass and deep hypothermic circulatory arrest. METHODS: Crossbred piglets (5 to 7 kg) were cooled with cardiopulmonary bypass, followed by 120-min deep hypothermic circulatory arrest. Animals were then warmed to 38 degrees C, removed from bypass, and maintained for 120 min. Methylprednisolone (60 mg/kg) was administered in the cardiopulmonary bypass pump prime (intraoperative glucocorticoids) or 6 hours before bypass (30 mg/kg) in addition to the intraoperative dose (30 mg/kg; preoperative and intraoperative glucocorticoids). Controls (no glucocorticoids) received saline. RESULTS: Pulmonary vascular resistance in controls increased from a baseline of 152 +/- 40 to 364 +/- 29 dynes. s/cm(5) at 2 hours of recovery (p < 0.001). Intraoperative glucocorticoids did not alleviate the increase in pulmonary vascular resistance (301 +/- 55 dynes. s/cm(5) at 2 hours of recovery, p < 0.001). However, animals receiving pre and intraoperative glucocorticoids had no increase in pulmonary vascular resistance (155 +/- 54 dynes. s/cm(5)). Plasma endothelin-1 in controls increased from 1.3 +/- 0.2 at baseline to 9.9 +/- 2.0 pg/mL at 2 hours recovery (p < 0.01), whereas glucocorticoid-treated animals had lower endothelin-1 levels (4.5 +/- 2.1 pg/ml, preoperative and intraoperative glucocorticoids; 4.9 +/- 1.7 pg/mL, intraoperative glucocorticoids) at the end of recovery (p < 0.05). Intracellular adhesion molecule-1 in lung tissue was lower in animals receiving pre and intraoperative glucocorticoids (p < 0.05). Myeloperoxidase activity was elevated in control lungs at 2 hours of recovery compared with glucocorticoid-treated groups (p < 0.05). Inhibitor kappaBalpha, the inhibitor of nuclear factor-kappaB, was higher in lungs of animals receiving glucocorticoids compared with controls (p < 0.05). CONCLUSIONS: Glucocorticoids prevented pulmonary hypertension after cardiopulmonary bypass and deep hypothermic circulatory arrest, which was associated with reduced plasma endothelin-1. Glucocorticoids also reduced pulmonary intercellular adhesion molecule-1 and myeloperoxidase activity. Inhibition of nuclear factor-kappaB, along with reduced neutrophil activation, contributed to glucocorticoid alleviation of pulmonary hypertension after cardiopulmonary bypass and deep hypothermic circulatory arrest.     

PS-341对小鼠重症急性胰腺炎核因子-κB活化的影响

目的观察PS-341对重症急性胰腺炎(SAP)小鼠胰腺组织核因子-κB(NF-κB)活化的影响,阐明PS-341对SAP的作用机制。方法采用连续7次腹内注射雨蛙素(每次间隔1h)及脂多糖制作小鼠SAP模型,将60只ICR雌性小鼠随机分为PS-341治疗组(注射脂多糖前0.5h腹内注射0.5mg/kgPS-341),模型对照组(注射脂多糖前0.5h腹内注射50%DMSO),空白对照组(生理盐水制模)。最后一次注射雨蛙素后2h麻醉小鼠,取血检测血淀粉酶,光镜下观察小鼠胰腺和肺脏的病理形态,测定胰腺组织中髓过氧化物酶水平,实时荧光定量PCR测定胰腺组织中黏附分子(ICAM-1)的含量,免疫印迹法(Westernblotting)检测胰腺组织中IκBα的表达,电泳迁移率实验(EMSA)测定NF-κB活性。结果 PS-341治疗组和模型对照组比较,胰腺组织中I-κB降解减少,NF-κB活性显著下降,血清淀粉酶、MPO、胰腺组织中细胞黏附分子ICAM-1的表达都明显降低(P<0.05)。胰腺和肺脏组织病理学有明显的改善(P<0.05)。结论 PS-341通过抑制胰腺内NF-κB活化而抑制炎症反应。PS-341可能是治疗SAP的一个新措施。     

氯化钆预处理对ANP肺损伤大鼠肺泡巨噬细胞中CYLD及NF-κB的影响

目的:观察氯化钆(GdCl3)预处理对性坏死性胰腺炎(ANP)大鼠肺泡巨噬细胞(AMs)肿瘤抑制因子CYLD及NF-κB的影响,探讨CYLD在ANP肺损伤中所起的作用。方法:36只SD大鼠随机分成正常对照组,ANP组,GdCl3预处理组。采用5%牛磺胆酸钠逆行性胰胆管注射制备ANP动物模型,GdCl3预处理组在造模前30 min经尾静脉注射GdCl3(10 mg/kg)。术后6 h处死各组动物,经支气管肺泡灌洗获取肺泡AMs,检测支气管肺泡灌洗液(BALF)中TNF-α和IL-1β含量,Western blot检测AMs中NF-κB及CYLD活性水平。检测肺组织髓过氧化物酶(MPO)的水平变化,并行肺组织病理学检查。结果:假手术组肺组织未见病理改变,ANP组和GdCl3预处理组肺组织均出现充血、水肿、炎性渗出等病理改变,但GdCl3预处理组病变程度轻与ANP组;ANP组肺组织的MPO活性,以及BALF的TNF-α,IL-1β含量较正常对照组明显升高(均P<0.05);正常对照组,ANP组,GdCl3预处理组AMs核蛋白NF-κB的表达量分别为0.08±0.03,0.18±0.06及0.11±0.04,3组AMs的CYLD的表达量分别为0.32±0.09,0.15±0.05和0.27±0.07。ANP组,GdCl3预处理组AMs中NF-κB与CYLD的表达活性均呈负相关(r=-0.708,r=-0.571,均P<0.05)。结论:ANP肺损伤中存在CYLD低表达和NF-κB活化,GdCl3预处理能通过增加CYLD表达,减少NF-κB活化,进而减轻肺损伤。     

E-cadherin、vimentin、snail及NF-κB在胃癌组织中的表达及其与淋巴转移的关系

目的本研究通过分析上皮细胞-间质转型(Epithelial to mesenchymal transition,EMT)相关通路蛋白E-cadherin、vimentin、snail及NF-κB在胃癌淋巴转移组及无转移组中的表达情况,探讨EMT在胃癌淋巴转移中的可能作用。方法选取淋巴结转移者31例(有淋巴结转移组),无淋巴结转移者25例(无淋巴结转移组),取其癌组织,通过免疫组化方法检测E-cadherin、vimentin、snail及NF-κB在相关组织中的表达情况,并通过统计学分析两组间的表达差异。结果在胃癌组织中,有淋巴结转移组E-cadherin的表达明显低于无淋巴结转移组,而vimentin与其相反,有淋巴结转移组的表达明显高于无淋巴结转移组,两者比较均有统计学差异(P0.05);同时有淋巴结转移组snail的表达明显低于无淋巴结转移组,NF-κB在有淋巴结转移组的表达明显高于无淋巴结转移组,两者比较均有统计学差异(P0.05)。相关性分析提示E-cadherin的表达与NF-κB表达相关,而vimentin及snail的表达则与其无关。结论 E-cadherin及vimentin可能通过NF-κB及snail调节表达,通过EMT参与胃癌淋巴转移,其表达高低可以作为淋巴转移发生几率的预测,联合检测可作为重要的生物学指标,用于术前胃癌检测。     

大鼠肾移植后载脂蛋白M的表达变化及其在急性排斥反应中的作用和机制

目的 观察大鼠肾移植后载脂蛋白M(apoM)的表达,探讨apoM在急性排斥反应(AR)中的作用及机制.方法 以SD大鼠和Wistar大鼠作为供鼠,Wistar大鼠作为受鼠,建立同系和同种大鼠原位肾移植模型.实验共分3组,对照组取同系移植受鼠,AR组和PDTC组取同种移植受鼠,其中PDIC组受鼠术后0.5 h注射核因子-κB(NF-κB)抑制剂吡咯烷二硫代氨基甲酸盐(PDTC),其余2组注射等量生理盐水.术后1、3、5和7d,取各组血清和移植肾组织进行检测,采用蛋白质印迹法检测NF-κB P65和apoM蛋白的表达,采用实时聚合酶链反应法检测apoM、穿孔素和颗粒酶BmRNA的表达,并对各检测指标进行相关性分析.结果 术后各时间点,AR组和PDTC组apoM、穿孔素和颗粒酶BmRNA的表达水平均明显高于同期对照组(P＜0.01),而PDTC组3种mRNA的表达水平均较同期AR组显著降低(P＜0.01).AR组和PDTC组apoM和NF-κBP65蛋白的表达均较同期对照组明显增高(P＜0.01),PDTC组2种蛋白的表达水平均较同期AR组显著降低(P＜0.01).经相关性分析,apoM蛋白与NF-κB P65蛋白的表达呈直线正相关(r=0.469、P＜0.05),apoM mRNA与穿孔素和颗粒酶BmRNA的表达均呈正相关(r=0.731、P＜0.0l,r=0.514,P＜0.05).结论 同种肾移植后,受鼠移植肾组织内apoM的表达显著上调,其可能通过NF-κB的介导参与AR的发生.