RASSF1A基因启动子甲基化与贲门癌的相关性

目的 探讨抑癌基因RAS相关区域家族1基因(RASSF1A)在贲门癌组织中的表达与RASSF1A基因肩动子甲基化的关系.方法 运用RT-PCR方法检测35例贲门癌组织(A组)和20例贲门正常组织(B组)中RASSF1A的表达,并运用甲基化特异PCR(MSP)方法检测这些组织中RASSF1A基因启动子的甲基化情况.结果 RASSF1A基因在A组中有25例(71%)存在表达缺失,明显多于B组的3例(15%)(P<0.05).A组的RASSF1A基因启动子甲基化频率62%,明显高于B组的20%(P<0.05).结论 贲门癌组织中RASSF1A基因启动子的高甲基化是引起RASSF1A基因表达下调的重要原因,在肿瘤的发生和发展中起重要的调控作用.     

甲状腺乳头状癌组织中RASSF1A基因启动子甲基化与临床病理学的关系

目的：探讨甲状腺乳头状癌及癌旁组织中RASSF1A基因启动子甲基化改变的特点与临床特征的关系。方法：从甲状腺乳头状癌及癌旁组织中提取基因组DNA，采用甲基化特异性PCR检测RASSF1A基因启动子甲基化情况。结果：（1）甲状腺乳头状癌组织中RASSF1A基因启动子甲基化的发生率为55．9％（19／34），癌旁组织中RASSF1A基因启动子的甲基化的发生率为23．5％（8／34），癌组织中RASSF1A基因启动子甲基化显著高于癌旁组织（P〈0．05）。（2）有淋巴结转移的甲状腺乳头状癌组织RASSF1A基因启动子的甲基化的发生率为77．8％（14／18），高于无淋巴结转移组的31．3％（5，16），差异有统计学意义（P〈0．05）。（3）临床Ⅱ～Ⅲ期甲状腺乳头状癌患者中RASSF1A基因启动子的甲基化发生率为88．9％（8／9），高于I期的44．0％（11／25），差异有统计学意义（P〈0．05）。结论：甲状腺乳头状癌组织中存在RASSF1A基因启动子区的异常甲基化，甲基化可能与甲状腺乳头状癌发生发展过程有关。     

胃癌患者血清RASSF1A基因启动子区甲基化检测及其临床意义

目的检测胃癌患者血清RASSF1A基因启动子区甲基化情况,探讨其在胃癌早期诊断和顶后评估中的可能作用。方法以甲基化特异性聚合酶链反应（MSP）检测47例胃腺癌患者、30例胃良性病变患者和旁组织标本以及术前、术后血标本行对照研究。结果胃腺癌患者血清RASSF1A基因启动子区甲基化率为34．0％（16／47）,显著高于胃良性病变患者（3．3％,1／30）和健康对照者（0％）（P〈0．01）。16例胃腺癌组织中5例（31．2％）检测到RASSF1A基因启动子区甲基化与胃癌患者性别、年龄、肿癌分化程度、有关转移以及血清癌胚抗原（CEA）水平均无相关性。结论血清RASSF1A基因启动子区甲基化检测可望为胃癌早期诊断和预后判断提供依据。     

胃癌术后复发转移与抑癌基因Syk启动子甲基化的研究

目的 研究胃癌组织中Syk基因启动子甲基化与术后复发转移的关系.方法 采用甲基化特异性PCR法检测胃癌组织及癌旁正常胃组织的Syk基因启动子甲基化状态.结果 在70例胃癌组织中,Syk基因启动子甲基化发生率为45.7％(32/70);在癌旁正常组织发生率分别为0(0/70);在胃癌组织中,Syk基因甲基化发生率明显高于癌旁正常组织(P＜0.001).检测到Syk基因启动子甲基化的32例病例中,有21例病例术后发生复发转移,发生率为65.6％(21/32);在未检测到Syk基因启动子甲基化的38例病例中,仅有7例病例术后发生复发转移,发生率为18.4％(7/38)(P＜0.001).结论 (1)Syk基因启动子甲基化与胃癌术后复发转移密切相关.(2)胃癌组织中Syk基因启动子甲基化的检测有助于胃癌术后复发转移的早期诊断及预后评估.     

胃癌BLU基因启动子区高甲基化的临床意义

目的研究BLU基因启动子区高甲基化在胃癌发生发展中的作用。方法应用甲基化特异性PCR技术分别检测92例胃癌组织与相应的癌旁组织以及79例胃癌患者与79例正常人外周血BLU基因甲基化水平,分析BLU基因甲基化与临床病理参数的相关性。结果胃癌组织BLU基因甲基化率高于癌旁组织(67.39%vs.52.17%)(P<0.05)。BLU基因甲基化与患者性别、年龄、肿瘤大小、分化程度、TNM分期和浸润深度之间无明显相关性(P>0.05),但与肿瘤淋巴结转移密切相关(P<0.05)。胃癌患者外周血BLU基因甲基化率与正常人外周血比较差异无统计学意义(63.29%vs.56.96%)(P>0.05)。结论 BLU基因启动子的CpG岛在胃癌组织存在高甲基化现象,提示BLU基因的高甲基化可能与抑癌基因被失活从而导致胃癌的发生有关。BLU甲基化可能参与胃癌淋巴结转移。     

Ras相关区域家族1A基因在宫颈癌组织中的表达及其甲基化调控研究

目的探讨Ras相关区域家族(RASSF)1A基因在宫颈癌中的作用。方法采用实时荧光定量聚合酶链反应(RT-PCR)技术检测宫颈癌中RASSF1A基因的表达状况;采用甲基化特异PCR技术检测RASSF1A启动子区5c-CpG岛的甲基化状态;通过细胞增殖和侵袭实验检测RASSF1A在宫颈癌细胞中的功能。结果本研究检测了65例宫颈癌和20份正常宫颈组织样本中RASSF1A的表达水平,结果显示其在宫颈癌中的表达水平明显低于正常宫颈组织,且差异有统计学意义。RASSF1A的表达与患者的年龄、淋巴结转移、肿瘤大小及病理类型无关,而与肿瘤的TNM分期有关。宫颈癌组织中RASSF1A启动子区5c-CpG岛的甲基化水平明显高于正常宫颈组织。RASSF1A可以抑制宫颈癌细胞的增殖和侵袭。结论 RASSF1A基因启动子区5c-CpG岛的高甲基化可能是参与宫颈细胞癌变的重要机制之一。     

LMX1A基因启动子在胃癌中的异常甲基化研究

目的研究LMX1A基因启动子在胃癌细胞中的甲基化状态。方法运用甲基化特异聚合酶链反应(MSP)法检测30例原发胃癌和癌旁组织中LMX1A基因的甲基化水平。甲基化修饰后亚硫酸盐测序聚合酶链反应(BSP)分析胃癌细胞MKN45细胞LMX1A基因启动子CpG岛甲基化状态。提取细胞RNA,通过实时定量聚合酶链反应(PCR)检测LMX1A基因mRNA在不同浓度的DNA甲基化酶抑制剂5′-杂氮-2′-脱氧胞嘧啶(5-aza-dC)处理MKN45细胞后,LMX1A基因mRNA的改变情况。结果原发性胃癌的甲基化异常检出率是33%(10/30)。LMX1A基因在MKN45细胞中存在高甲基化状态,MKN45细胞经5-aza-dC处理后LMX1A基因mRNA表达明显上调。结论 LMX1A基因在原发性胃癌中存在甲基化异常,说明LMX1A基因甲基化异常可能参与胃癌的发生。     

原发性肝癌中RASSF1A基因表达失活及其临床意义

目的 研究肝癌组织中的抑癌基因RASSF1A的表达情况和由于启动区异常甲基化导致其基因外失活的状况,并分析DNA异常甲基化与肝癌临床相关因素之间的关系.方法 利用RT-PCR和MS-PCR的方法,结合DNA测序和TaqⅠ酶切消化法,分析24例肝癌标本、4株肝癌细胞株中RASSF1A基因的表达情况,以及其基因启动区异常甲基化的情况.采用甲基化抑制剂5'-Aza-CdR处理肝癌细胞株,观察RASSF1A重新表达的情况.结果 66.7%的肝癌组织未表达RASSF1A;4株肝癌细胞株中仅1株检测到RASSF1A的表达.83.3%的肝癌组织及4株肝癌细胞株都发生了异常甲基化,而正常肝组织和正常肝细胞株(L02)中却未发现甲基化.甲基化与肝硬化、乙肝表面抗原、肿瘤分化程度及血管浸润和远处转移有相关性.原来RASSF1A表达失活的3株肝癌细胞株经甲基化抑制剂5'-Aza-CdR处理后,又重新恢复了表达.结论 基因转录启动区的异常甲基化是导致肝癌中RASSF1A表达失活的主要原因.检测RASSF1A启动区异常甲基化可作为一种有潜在应用价值的生物分子指标来用于肝癌的早期发现、早期诊断以及预后的判断.     

乳腺癌组织中C-erbB2基因启动子区CpG岛甲基化分析

目的了解乳腺癌组织中致癌基因C-erbB2启动子区CpG岛的甲基化状态。方法收集经病理确诊的39例乳腺癌患者甲醛固定的癌组织及相应的癌旁组织各39份;采用甲基化特异聚合酶链反应(MSP)检测C-erbB2基因启动子区CpG岛的甲基化状态。结果乳腺癌组织中C-erbB2基因启动子区CpG岛的甲基化率(51.3%)低于癌旁组织中存在的甲基化率(74.4%),二者之间差异有统计学意义(P<0.05)。结论所检测标本显示乳腺癌组织与癌旁组织间C-erbB2基因启动子区CpG岛甲基化率差异有统计学意义,提示C-erbB2的低甲基化可能是C-erbB2蛋白高表达和乳腺癌发生的原因之一。     

结肠腺瘤性息肉病基因异常甲基化在上皮性卵巢癌中的检测及临床意义

目的观察结肠腺瘤性息肉病(APC)基因异常甲基化在上皮性卵巢癌中的作用及临床意义。方法59例上皮性卵巢癌组织原发灶、32例相应的盆腹腔转移灶、12例癌旁卵巢组织及30例正常卵巢组织,采用甲基化特异性聚合酶链式反应(M SP)法检测APC基因启动子区甲基化状态。结果上皮性卵巢癌组织原发灶及相应的盆腹腔转移灶中存在APC基因启动子区异常甲基化,发生率分别为32.2%、40.6%,显著高于正常卵巢组织(P<0.01)。12例癌旁卵巢组织中1例检测到APC基因启动子区甲基化,30例正常卵巢组织未检测到APC基因启动子区甲基化。APC基因启动子区甲基化的发生率在临床Ⅰ期和Ⅱ期显著低于Ⅲ期和Ⅳ期(P<0.05),在高分化癌中低于低分化癌(P<0.05)。结论APC基因启动子区异常甲基化与上皮性卵巢癌发生密切相关,并可能与上皮性卵巢癌临床分期及分化程度有关。     

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.     

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.     

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.