Avian-specific TLRs and downstream effector responses to CpG-induction in chicken macrophages

Chickens possess toll-like receptor (TLR15), a pattern recognition receptor (PRR) absent in mammals. We characterized the regulation and mechanism of CpG responsiveness via TLRs in chicken macrophage HD11 cells. TLR15 was significantly upregulated after induction with B- and C-type CpG oligonucleotides (ODN), tripalmitoylated lipopeptide (PAM3CSK4), Escherichia coli- and Salmonella enteritidis-derived lipopolysaccharide (LPS). In response to CpG-ODN inhibitor, TLR15 and IL1B were downregulated, but TLR21 was upregulated. IL1B was upregulated with CpG-ODN and downregulated after inhibitor treatment. The results suggest that responsiveness to different types of CpG-ODN in chicken macrophages requires multiple receptors, each with unique variation in expression. We utilized RNA interference (RNAi) technology to examine myeloid differentiation primary response gene (MyD88) dependency of TLR15 and TLR21. HD11 macrophages transfected with multiple MyD88-target siRNAs exhibited 70% decrease in MyD88 mRNA expression. IL1B was upregulated with CpG induction in cells with no reduction of MyD88 mRNA levels, but not in cells with 70% MyD88 reduction. Therefore, induction through TLR15 in response to CpG-ODN operates via the MyD88-dependent pathway in chicken macrophages.     

A flavonoid component from Docynia delavayi (Franch.) Schneid represses transplanted H22 hepatoma growth and exhibits low toxic effect on tumor-bearing mice

The fruit of Docynia delavayi (Franch.) Schneid is a kind of popular food in southwestern areas of China. Additionally, its rhizome has been long used as a folk medicine in the treatment of liver cancer by local people. Chrysin is a kind of flavonoid which induces cancer cell death in vitro. However, its anti-tumor activity in vivo and toxicological effects on the tumor-bearing animals still remain poorly understood. In this study, we obtained four flavonoids from this herb. Among them, chrysin showed the strongest cytotoxic effect on an array of cultured tumor cells. Further investigations revealed that it significantly repressed transplanted H22 ascitic hepatic tumor cell growth in vivo. Moreover, this compound displayed little toxic effects. Additionally, we demonstrated that in transplanted tumor tissues, chrysin not only activated caspase-3 and induced apoptosis, but also inhibited the production of vascular endothelial growth factor (VEGF) and suppressed angiogenesis. These data showed that chrysin exhibited prominent anti-tumor activities and low toxic effects in vivo.     

做好伦理委员会主席之我见

伦理委员会主席在伦理委员会中扮演着一个相当重要的角色。他必须是一个相当热情和热心于伦理委员会工作的领导者,他必须是一个医学、法学、伦理学和管理学的专家。伦理委员会主席的主要职责就是要积极鼓励伦理委员会委员做好伦理评审工作,不要受任何外界因素的干扰。     

腹主动脉阻断术临床原理及其上中下段安全时限探讨——兼述缺血再灌注损伤机制与对策及“二叉树耐受法则”

目的深入探讨腹主动脉阻断术的临床原理及其高中低位阻断安全时限等问题,以期在临床上安全地使用该技术。方法1980年-1982年我们首次进行了腹主动脉阻断安全时限及其阻断与撤钳后病理生理变化的前瞻性实验研究。结果表明:犬腹主动脉阻断25min为安全时限;在阻断安全时限内,犬体内血液动力学、血气酸碱、血液生化和主要的脏器超微结构(脑肺肝肾胰肠脊髓)仅发生轻度可逆性改变;如超出安全时限,上述指标则会发生难以代偿的严重改变。基于广义生命时空场论学说,通过对腹主动脉阻断术解剖学基础,腹主动脉阻断后与撤钳后综合征群(呼吸宭迫综合征、急性高血压性脑水肿、多脏器微栓塞病细胞综合征、撤钳后中枢性呼吸衰竭)及腹主动脉阻断所致的缺血再灌注损伤病理生理与细胞分子生物学机制等讨论,并根据近期实验与临床研究结果和结合文献复习对相关问题做了探讨,对临床上预防和治疗腹主动脉阻断术所致的缺血再灌注损伤提出了一整套对策。此外还叙述了预防腹主动脉阻断术并发症的远端主动脉灌注、脑脊液引流以及硬膜外冷却、控制性再灌注与缺血预/后处理等几种新技术。结果如果超出腹主动脉阻断术安全时限,则在术中与术后将发生缺血再灌注损伤、全身炎症反应综合征和多脏器衰竭。临床上,人类一次性持续腹主动脉阻断术安全时限如下:高位(T12水平,腹腔干A上)、中位(L2水平,肾A上)与低位(L4水平,髂总A上)均不能轻易超越25-30min。如术中须延时宁可采用间断阻断法。结论如果"二叉树耐受法则"(即体内任何一处大血管阻断均不能超出其固有安全时限,否则受术者非死必伤)被严格遵守,则腹主动脉阻断术中与术后病人的安全将得到保证。     

(−)Epigallocatechin-3-gallate inhibits the spontaneous firing of rat locus coeruleus neuron

(−)Epigallocatechin-3-gallate (EGCG), a tea catechin, has been known to cause many biological actions, such as anxiolytic and hypotensive effects in behavioral studies. However, to date, few reports investigate its neuronal modulation. In this study, intracellular recording was used to test the neuronal modulation of different catechins on locus coeruleus (LC) neuron, which has been demonstrated to be affected by cardiovascular function regulation and stressful events. Several catechins (1–1000 μM) were tested, including: (−)catechin (C), (−)catechingallate (CG), (−)epicatechin (EC), (−)epicatechin-3-gallate (ECG), (−)epigallocatechin (EGC) and EGCG. The results showed that catechins EC, ECG, EGC and EGCG could inhibit the spontaneous firing of the LC neurons; furthermore, these catechins show potency and efficacy in the order of EGCG > ECG > EC ≈ EGC. Among the tested catechins, EGCG was the most potent in inhibiting LC's spontaneous firing with IC₅₀ of 20.5 μM. This caused us to further examine the EGCG's desensitization and tolerance properties. When continuously administering EGCG at 1–300 μM for 20 min, no acute desensitization appeared. However, repeated applications of 300 μM EGCG at 5 min each time showed different results. The second and third applications induced less responses compared to that of the first application, suggesting a development of tolerance towards EGCG in inhibiting LC neuronal activity. Our data suggest that EGCG can inhibit LC neuron's spontaneous firing in a dose-dependent manner, with developed tolerance only when high concentration of EGCG is repeatedly applied.     

TSA联合基因工程腺病毒H101治疗食管癌皮下移植瘤的研究

目的 研究曲古霉素A(TSA)对基因工程腺病毒H101杀伤食管癌EC9706细胞作用的影响,探讨HDAC抑制剂在腺病毒载体基因治疗中应用的可能性和作用机制.方法1)先成瘤后治疗组,构建裸鼠食管癌移植瘤模型,待肿瘤长至肉眼可见的肿块(约8mm ×7mm)后分组.TSA治疗组:每只每次瘤内注射1.0 μmol/L TSA;...     

环六亚甲基双乙酰胺诱导EC9706细胞分化中细胞增殖与形态结构的变化

目的：观察环六亚甲基双乙酰胺（hexamethylene bisacetamide,HMBA）对人食管癌EC9706细胞的增殖以及形态结构的影响。方法：采用不同浓度的HMBA（3、5、8、10mmol/L）处理人食管癌EC9706细胞,实验同时设立对照组（未加HMBA）。测定各组细胞的生长曲线、分裂指数,并在光镜下观察HMBA诱导前后细胞增殖以及形态结构的变化。结果：与对照组比较,经3、5、8、10mmol/L的HMBA处理后,EC9706细胞的生长和增殖受到抑制,其抑制率依次分别为52.875%、80.579%、83.617%、90.272%,差异均具有统计学意久（P〈0.05或P〈0.01）,且呈浓度-效应关系。光镜下观察HMBA处理组的EC9706细胞较对照组细胞的体积增大,且趋于扁平铺展状态,细胞大小较为一致,排列较为规则。结论：经HMBA诱导处理后的人食管癌EC9706细胞出现了与同组织来源的正常上皮细胞相似的形态与结构特征,表现出肿瘤细胞恶性表型逆转的特征。     

维甲酸对人食管癌细胞核基质蛋白表达的影响

目的：探讨维甲酸对人食管癌EC9706细胞核基质蛋白表达的影响,了解食管癌变与核基质蛋白的关系。方法：人食管癌EC9706细胞采用维甲酸诱导分化处理48h后,进行核基质蛋白提取,采用双向电泳技术检测维甲酸处理前后核基质蛋白表达的变化。结果：维甲酸处理前后的EC9706细胞中多种核基质蛋白的表达发生了变化,其中处理后表达下调的有4个核基质蛋白,表达上调的11个,新出现的有3个蛋白质点。结论：维甲酸对体外培养的人食管癌EC9706细胞核基质蛋白的表达种类及水平有显著影响,核基质蛋白表达的变化可能与食管的癌变有关。