基于p53介导自噬通路探讨臭椿酮对顺铂耐药胃癌细胞株耐药性的影响

目的探讨臭椿酮对顺铂(DDP)耐药胃癌细胞株SGC-7901/DDP耐药性的影响及其机制。方法采用噻唑蓝(MTT)法检测不同质量浓度臭椿酮对SGC-7901/DDP细胞活力的影响以筛选无毒作用浓度。将体外培养的SGC-7901/DDP细胞分为臭椿酮低浓度(0.2 mg/mL)+DDP(2μg/m L)组、臭椿酮中浓度(0.4 mg/mL)+DDP(2μg/m L)组、臭椿酮高浓度(0.8mg/mL)+DDP(2μg/m L)组考察臭椿酮对SGC-7901/DDP细胞DDP敏感性的影响;将体外培养的SGC-7901/DDP细胞分为对照组、DDP(2μg/m L)组、DDP(2μg/mL)+Pifithrin-α(20μmol/L)组、臭椿酮(0.8 mg/mL)+DDP组、臭椿酮+DDP(2μg/m L)+Pifithrin-α(20μmol/L)组考察p53信号通路与药物作用的关系;采用MTT法检测SGC-7901/DDP细胞活力,流式细胞仪检测SGC-7901/DDP细胞凋亡率,免疫印迹法检测SGC-7901/DDP细胞中LC3Ⅱ、LC3Ⅰ、Beclin1和p53蛋白表达水平。结果 0.2、0.4、0.8 mg/mL臭椿酮对SGC-7901/DDP细胞未产生明显细胞毒性。与DDP组相比,臭椿酮低浓度+DDP组、臭椿酮中浓度+DDP组、臭椿酮高浓度+DDP组细胞活力明显降低,凋亡率、LC3Ⅱ/LC3Ⅰ值和Beclin1、p53蛋白表达水平明显升高(P0.05),且呈浓度依赖性;而DDP组和对照组之间差异无统计学意义(P0.05);给予Pifithrin-α作用后的DDP+Pifithrin-α组和臭椿酮+DDP+Pifithrin-α组细胞活力较相应对照DDP组、臭椿酮+DDP组明显升高,而细胞凋亡率、LC3Ⅱ/LC3Ⅰ值和Beclin1、p53蛋白表达水平较DDP组、臭椿酮+DDP组明显降低(P0.05)。结论臭椿酮可通过p53通路诱导自噬逆转SGC-7901/DDP细胞对DDP的耐药性。     

藤茶蛇葡萄素抗人胃癌细胞作用的实验研究

目的:探讨藤茶蛇葡萄素的体外抗肿瘤作用。方法:采用MTT法、生长曲线法、细胞集落形成法观察蛇葡萄素对人胃癌SGC-7901细胞的抑制作用。结果:蛇葡萄素能明显抑制体外培养的SGC-7901细胞的生长,MTT法IC50为11.19μg/mL;细胞生长曲线法提示其对SGC-7901细胞的生长也有明显的抑制作用;集落形成法,当药物浓度在9.90μg/mL以上时抑制率为100%,当药物浓度为6.60μg/mL时抑制率为72.3%,当药物浓度为4.40μg/mL时抑制率为36.0%。结论:蛇葡萄素对体外SGC-7901细胞的生长有明显的抑制作用。     

长叶胡颓子体外抑制肿瘤细胞增殖的研究

目的研究长叶胡颓子乙醇提取物、三萜酸部位、熊果酸对4株肿瘤细胞增殖的体外抑制作用以及熊果酸抗肿瘤作用机制。方法采用MTT法测定长叶胡颓子乙醇提取物、三萜酸部位和熊果酸在25、50、100、200μg/mL时对人胃癌细胞SGC-7901、BGC-823、肠癌细胞LOVO、HCT-8实体瘤细胞增殖的体外抑制作用;并在上述药物剂量下,观察熊果酸作用72 h后对SGC-7901细胞形态的影响,以及作用24 h后对SGC-7901细胞凋亡的诱导作用。结果长叶胡颓子乙醇提取物、三萜酸部位、熊果酸对4株肿瘤细胞的增殖具有较强的体外抑制作用,其中对于胃癌细胞的抑制作用为熊果酸>三萜酸部位>乙醇提取物;对肠癌细胞的抑制作用为三萜酸部位>熊果酸>乙醇提取物,同时熊果酸能显著改变SGC-7901细胞的形态,并且SGC-7901细胞的凋亡率与熊果酸的剂量呈相关性。结论三萜酸是长叶胡颓子发挥体外抗肠癌细胞增殖作用的主要有效部位;熊果酸是其发挥体外抗胃癌细胞增殖作用的主要活性成分,熊果酸抑制胃癌细胞增殖机制为诱导细胞凋亡,为开发新的抗癌药物提供参考。     

丙泊酚对胃癌SGC-7901细胞增殖、凋亡的影响及其机制研究

目的:探究麻醉药丙泊酚对人胃癌SGC-7901细胞体外增殖、凋亡的影响及其作用机制.方法:体外培养人胃癌SGC-7901细胞,分别使用不同浓度(0,2,4,6μg·ml-1)的丙泊酚干预SGC-7901细胞(其中0μg·ml-1为对照组),采用克隆形成实验测定丙泊酚对SGC-7901细胞克隆形成能力的影响,噻唑蓝(MT...     

齐墩果酸对顺铂耐药胃癌SGC-7901细胞增殖的影响及其机制研究

目的探讨齐墩果酸对顺铂耐药胃癌SGC-7901细胞增殖的影响及其作用机制。方法体外诱导建立人胃癌顺铂耐药细胞株SGC-7901/CDDP,MTT比色法检测SGC-7901/CDDP细胞活力;适时荧光定量PCR分析凋亡相关基因Bcl-2及BaxmRNA的表达。结果MTT实验证明齐墩果酸对SGC-7901/CDDP细胞的生长有抑制作用,100μmol.L-1齐墩果酸作用72h对SGC-7901/CDDP细胞的抑制率达62%,并表现为时间和剂量依赖性;适时荧光定量PCR实验证明,SGC-7901/CDDP细胞经齐墩果酸处理后,促凋亡基因Bax表达上调,抗凋亡基因Bcl-2表达下调。结论齐墩果酸在体外能够抑制SGC-7901/CDDP细胞增殖,并使促凋亡基因Bax表达升高,抗凋亡基因Bcl-2表达降低,上调Bax和下调Bcl-2mRNA的表达可能是其作用机制之一。     

黄荆子乙酸乙酯提取物体内外对胃癌SGC-7901细胞作用的研究

目的研究黄荆子乙酸乙酯提取物(EVn-50)在体内外对人胃癌SGC-7901细胞的作用。方法细胞计数法检测EVn-50对人胃癌SGC-7901细胞生长增殖的抑制作用,并绘制细胞生长曲线;平板克隆试验测定细胞集落形成率;建立SGC-7901裸鼠异种移植瘤模型,绘制移植瘤生长曲线,计算经EVn-50治疗后的肿瘤抑制率;光镜和电镜观察肿瘤组织病理变化。结果在体外,1、10、100mg·L-1的EVn-50均能抑制人胃癌SGC-7901细胞生长和增殖,呈浓度和时间依赖性;与对照组比较,细胞集落形成率明显下降(P<0.05);在体内,EVn-50能够抑制SGC-7901细胞裸鼠异种移植瘤生长,5、10、20mg·kg-1的EVn-50对移植瘤的瘤重抑制率分别为32%、43%和56%,且呈浓度依赖性;病理学观察结果,EVn-50可引起SGC-7901细胞坏死,诱导SGC-7901细胞凋亡。结论EVn-50在体内外均可抑制SGC-7901细胞生长和增殖,并在体内诱导其凋亡。     

莪术油对人胃癌SGC-7901细胞增殖与凋亡的影响

目的探讨莪术油（zedoary turmeric oil）对体外培养胃癌SGC-7901细胞增殖及诱导凋亡的作用。方法胃癌SGC-7901细胞经常规培养,给予不同浓度的莪术油处理,观察细胞生长情况,MMT比色法检测细胞增殖,计算抑制率;流式细胞技术检测SGC-7901细胞的凋亡,并计算凋亡指数。结果莪术油对SGC-7901细胞增殖的抑制率随浓度的增加而增高（P〈0．01）,莪术油诱导SGC-7901细胞凋亡率较对照组显著增加（P〈0．01）。结论莪术油在体外可以抑制胃癌SGC-7901细胞增殖,促进细胞凋亡。     

姜黄素诱导人胃癌SGC-7901细胞凋亡

目的 探讨姜黄素诱导人胃癌SGC-7901细胞凋亡的作用.方法 采用噻唑蓝(MTT)比色法检测人胃癌SGC-7901细胞生长活力;Hoechst 33258核染色观察细胞形态学变化;流式细胞术检测细胞周期及细胞凋亡率;比色法检测Caspase-3、8、9活性.结果 姜黄素(5.0、10.0、20.0、40.0、80.0 μmol/L)明显抑制SGC-7901细胞牛长并呈剂量依赖关系,48 h的IC50值为(23.65±3.15)μmol/L,细胞核经Hoechst 33258染色出现浓染致密的固缩形态和颗粒状荧光.与对照组相比,姜黄素处理后凋亡细胞比例增加;姜黄素处理SGC-7901细胞48 h后Caspase-3、8、9的活性明显增强.结论 姜黄素可通过激活Caspase级联活化而抑制人胃癌SGC-7901细胞生长并诱导其凋亡.     

维生素K2与苯那普利诱导胃癌细胞凋亡及抑制血管生成的体外实验研究

目的:通过体外细胞培养观察维生素K2联合苯那普利对人胃癌SGC-7901细胞的影响,以探讨两者对胃癌细胞的影响及有无协同作用。方法:通过人胃癌SGC-7901细胞培养,将处于对数生长期的SGC-7901细胞分成5组:药物组(维生素K2组、苯那普利组、联合组)、阴性对照组和空白对照组,阴性对照组不加药,空白对照组不加细胞。加入不同终浓度的药物(维生素K2:5、10、20、40、80μmol/L)或(苯那普利:0.625、1.25、2.5、5、10μg/mL)或(维生素K2+苯那普利)。分别培养24、48和72 h。利用MTT实验检测细胞生长抑制率,流式细胞仪Annexin V/PI双染法及梯状DNA电泳检测细胞凋亡情况,RT-PCR测定血管内皮生长因子(VEGF)表达。结果:药物组能抑制胃癌SGC-7901细胞的增殖,且具有明显的剂量-效应关系,在抑制细胞增殖、诱导细胞凋亡及抑制VEGF表达方面,联合组较单独药物组作用更强。结论:维生素K2与苯那普利联合有协同作用,能通过诱导细胞凋亡、抑制VEGF的表达抑制胃癌细胞增殖。     

甘草甜素对胃癌细胞株SGC-7901凋亡影响的体外研究

目的探讨甘草甜素（GL）抗肿瘤的机制,为GL在抗肿瘤方面的应用提供理论依据。方法采用流程式细胞仪检测胃癌细胞株SGC-7901凋亡。结果50,100,200μmol/LGL能够诱导胃癌细胞SGC-7901凋亡,凋亡率与剂量呈正相关,SGC-7901的凋亡随药物浓度及作用时间变化,细胞周期分布呈现G1期细胞比例逐渐增高,并出现典型的凋亡峰。结论GL能诱导胃癌细胞凋亡,并明显抑制癌细胞增殖,具有抗肿瘤作用。     

Efficacy of gut lavage,hemodialysis, and hemoperfusion in the therapy of paraquat or diquat intoxication

Clinical and in vitro investigations were carried out to test the efficacy of gut lavage, hemodialysis, and hemoperfusion in the treatment of poisoning with paraquat or diquat. In a patient suffering from diquat intoxication 130 times more diquat was removed by gut lavage 30 h after ingestion than was removed by complete aspiration of the gastric contents.Determination of in vitro clearances for paraquat and diquat by hemodialysis showed that, at serum concentrations of 1–2 ppm, such as are frequently encountered in poisoning in man, toxicologically relevant quantities of herbicide cannot be removed from the body. At a concentration of 20 ppm, on the other hand, hemodialysis proved to be effective, the clearance being 70 ml/min at a blood flow rate of 100 ml/min. The efficacy of hemoperfusion with coated activated charcoal was on the whole better. Especially at concentrations around 1–2 ppm, the clearance values for hemoperfusion were some 5–7 times higher than those for hemodialysis.In a patient suffering from paraquat poisoning, both hemodialysis as well as hemoperfusion were carried out. The in vitro results could be confirmed: At serum concentrations of paraquat less than 1 ppm no clearance could be obtained by hemodialysis while by hemoperfusion with activated charcoal quite high clearance values were measured and the serum level dropped down to zero.

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Zusammenfassung Klinische Untersuchungen und Laboratoriumsversuche wurden durchgeführt, um die Wirksamkeit von Darmspülung, Hämodialyse und Hämoperfusion bei Paraquat- und Deiquat-Vergiftungen zu prüfen.Bei einem Patienten wurde 30 Std nach Deiquat-Aufnahme durch Darmspülung 130mal mehr Deiquat entfernt als durch vollständige Aspiration des Mageninhaltes. In vitro-Versuche ergaben, daß bei Blutserumkonzentrationen von 1–2 ppm, die bei Vergiftungen oft gemessen werden, durch Hämodialyse keine toxikologisch relevanten Paraquat- oder Deiquat-Mengen entfernt werden können. Dagegen erwies sich die Hämodialyse bei 20 ppm und einer Blutumlaufgeschwindigkeit von 100 ml/min mit einer Clearance von 70 ml/min als wirksam. Die Hämoperfusion mit beschicheter Aktivkohle war in diesen Versuchen aber eindeutig überlegen, denn insbesondere bei Konzentrationen um 1–2 ppm waren die Clearance-Werte 5–7mal höher als bei der Hämodialyse.Die in vitro-Ergebnisse wurden bei einem Patienten mit einer Paraquat-Vergiftung bestätigt: Bei Konzentrationen unter 1 ppm war die Hämodialyse wirkungslos, während durch Hämoperfusion relativ hohe Clearance-Werte erreicht wurden, so daß der Serumspiegel rasch unter die Nachweisgrenze abfiel.

     

In vitro studies on sterically stabilized liposomes (SL) as enzyme carriers in organophosphorus (OP) antagonism

This study describes a new approach for organophosphorous (OP) antidotal treatment by encapsulating an OP hydrolyzing enzyme, OPA anhydrolase (OPAA), within sterically stabilized liposomes. The recombinant OPAA enzyme was derived from Alteromonas strain JD6. It has broad substrate specificity to a wide range of OP compounds: DFP and the nerve agents, soman and sarin. Liposomes encapsulating OPAA (SL)* were made by mechanical dispersion method. Hydrolysis of DFP by (SL)* was measured by following an increase of fluoride ion concentration using a fluoride ion selective electrode. OPAA entrapped in the carrier liposomes rapidly hydrolyze DFP, with the rate of DFP hydrolysis directly proportional to the amount of (SL)* added to the solution. Liposomal carriers containing no enzyme did not hydrolyze DFP. The reaction was linear and the rate of hydrolysis was first order in the substrate. This enzyme carrier system serves as a biodegradable protective environment for the recombinant OP-metabolizing enzyme, OPAA, resulting in prolongation of enzymatic concentration in the body. These studies suggest that the protection of OP intoxication can be strikingly enhanced by adding OPAA encapsulated within (SL)* to pralidoxime and atropine.     

Aquatic Insects and Trace Metals: Bioavailability,Bioaccumulation, and Toxicity

Abstract

The uptake of metals from food and water sources by insects is thought to be additive. For a given metal, the proportions taken up from water and food will depend both on the bioavailable concentration of the metal associated with each source and the mechanism and rate by which the metal enters the insect. Attempts to correlate insect trace metal concentrations with the trophic level of insects should be made with a knowledge of the feeding relationships of the individual taxa concerned. Pathways for the uptake of essential metals, such as copper and zinc, exist at the cellular level, and other nonessential metals, such as cadmium, also appear to enter via these routes. Within cells, trace metals can be bound to proteins or stored in granules. The internal distribution of metals among body tissues is very heterogeneous, and distribution patterns tend to be both metal and taxon specific. Trace metals associated with insects can be both bound on the surface of their chitinous exoskeleton and incorporated into body tissues. The quantities of trace meals accumulated by an individual reflect the net balance between the rate of metal influx from both dissolved and particulate sources and the rate of metal efflux from the organism. The toxicity of metals has been demonstrated at all levels of biological organization: cell, tissue, individual, population, and community. Much of the literature pertaining to the toxic effects of metals on aquatic insects is based on laboratory observations and, as such, it is difficult to extrapolate the data to insects in nature. The few experimental studies in nature suggest that trace metal contaminants can affect both the distribution and the abundance of aquatic insects. Insects have a largely unexploited potential as biomonitors of metal contamination in nature. A better understanding of the physico-chemical and biological mechanisms mediating trace metal bioavailability and exchange will facilitate the development of general predictive models relating trace metal concentrations in insects to those in their environment. Such models will facilitate the use of insects as contaminant biomonitors.     

Alzheimer’s disease – current trends in basic and clinical research. Highlights from the 16th ECNP

Advances in the molecular biological knowledge of neuronal nicotinic acetylcholine receptors (nAChRs) have led to a growing interest by the pharmaceutical industry in the development of novel compounds that selectively modulate nAChR function. The ability of (-)-nicotine, an activator of nAChRs, to enhance attentional aspects of cognition in animals and humans, to exert neuroprotective and anxiolytic-like effects, and presumably to mediate the negative correlation between smoking and Alzheimer's (and Parkinson's) Disease, has focused interest on the potential therapeutic utility of modulators of nAChR function for treatment of some of the deficits associated with these progressive, neurodegenerative conditions. Numerous compounds are known which activate nAChRs and which might serve as lead compounds toward the development of such agents. The pharmacologic diversity of neuronal nAChR subtypes suggests the possibility of developing selective compounds which would have more favourable side-effect profiles than existing agents. This broader class of agents, collectively called cholinergic channel modulators (ChCMs), is anticipated to encompass compounds which would have more favourable side-effect profiles than existing agents, which generally exhibit low selectivity. This selectivity may be achieved by preferentially activating some subtypes of nAChRs (i.e., Cholinergic Channel Activators, ChCAs) or inhibiting the function of other subtypes (Cholinergic Channel Inhibitors, ChCIs). An overview of the biology of nAChRs and the rationale for the use of ChCMs for the treatment of dementia related to neurodegenerative diseases are presented, followed by a discussion of lead compounds and compounds under consideration for clinical evaluation.     

Steroidal sapogenin contents in some domestic plants

In order to find out the values of the steroid resources for the future use. the compositions and contents of steroidal sapogenins from 13 domestic plants have been investigated. As a result,Dioscorea nipponica, D. quinqueloba andSmilax china were found to have large amount of diosgenin. And pennogenin inTrillium kamtschaticum andParis verticillata, yuccagenin inAllium fistulosum, hecogenin inAgave americana and neochlorogenin inSolanum nigum were appeared to be major steroidal sapogenins.