转bak基因促膀胱癌多药耐药细胞凋亡的研究(英文)

目的观察转入 bak 基因对膀胱癌多药耐药(MDR)细胞的杀伤效果,探讨其可能的机制。方法用脂质体将 bak 基因导入 MDR 细胞,通过原位杂交法检测 bak mRNA 的表达,同时用 SABC 免疫组化法分析 bak 和 Bcl-2的表达。采用细胞计数法检测细胞生长抑制率,流式细胞仪检测细胞周期的变化。荧光染色观察细胞形态。结果转入 bak 基因后,MDR 细胞的生长明显受抑制(P<0.05)。细胞周期分析可见凋亡峰,凋亡率35%。细胞中可见 bak 阳性表达(P<0.05),Bck-2表达显著减少(P<0.05)。凋亡细胞在荧光显做镜下形成凋亡小体。结论转入 bak 基因可显著促进 MDR 细胞的凋亡,其作用机制与下调 Bcl-2基因的表达有关。     

念珠菌对唑类药物耐药机理的探讨

文献报道念珠菌对唑类药物耐药机制有三，即膜通透性降低、靶酶改变及靶酶产生过多。本文对２６株分离自艾滋病患者的耐氟康唑白念珠菌及通过诱变获得的白念珠菌ＡＴＣＣ１４０５３五个氟康唑耐药突变菌落的耐药机制进行了初步探讨。根据唑类药物靶酶编码序列设计六对上下之间交叉重叠的引物，分六段（包括相当于调控序列所在部位）将目的基因扩增出来，采用Ｓｏｕｔｈｅｒｎ杂交、限制性片段多态性分析及聚合酶链反应－单链构象多态性分析等方法对所获目的片段进行了分析。结果排除了所有受试菌株因靶酶编码基因缺失而耐药的可能，单链构象多态性分析结果呈阳性，且耐药株之间也存在差异。故此，推测耐药性系因为靶酶编码序列多位点突变造成，这一点尚有待进一步证实。另外，本实验结果不能排除另两条耐药机理的存在     

Comparison of action of the anti-neoplastic drug lonidamine on drug-sensitive and drug-resistant human breast cancer cells:31 P and 13C nuclear magnetic resonance studies

Lonidamine (LND) is a relatively new anti-cancer drug,and several clinical trials have indicated that it may be effectivein combinations with other therapeutic modalities. LND isclassified within the metabolic inhibitor agents. Multidrugresistance (MDR) phenomenon is often associated with increasedenergy requirements, and enhanced glycolysis rate. These studieswere performed to delineate the mechanism of action of LNDon MDR human breast cancer cells, and to investigate whetherLND as a single agent, or in combination with anotheranti-metabolism drug, 2-deoxyglucose (2-DG), may be usefulagainst MDR tumors. The effects of LND on intact perfuseddrug-sensitive (WT) and 33-fold resistant to Adriamycin(Adr) MCF-7 cells, embedded in alginate micro capsules, were continuouslymonitored by ³¹P and ¹³C nuclearmagnetic resonance (NMR) spectroscopy. ³¹PNMR studies showed that LND induced intracellular acidificationand depletion of NTP in both WT and Adr cells. However, pH and NTPlevels decreased less in the Adr cells than in the WT cells(p < 0.05 for both parameters). ¹³CNMR demonstrated that LND inhibited lactate transport,and lactate signals were elevated in both cell lines. However, theintracellular lactate levels increased to a greater extentin the WT than in the Adr cells (p < 0.05).There were major differences in the effects of LND onmetabolism between sensitive and resistant cells.While LND enhanced glucose uptake in the WT cells, and itsadministration was followed by continuous increase oflactate signal, both processes were not affected by LNDin the Adr cells. 2-DG is a glucose analogue that inhibitsboth cellular uptake and utilization of glucose, leading to cell starvation. Combined treatment with LND and2-DG yielded at best additive, but not synergistic,cellular toxicity, and the metabolic effects of LNDwere attenuated by 2-DG. These results showed that the principalmechanism of action of LND is inhibition of lactate transportleading to intracellular lactate accumulation and acidificationin both WT and Adr cells. The Adr cells were only 2-fold resistantto LND (compared to the WT cells), and since cellular uptakeof alkaloid chemotherapy is improved in acidic environment,LND may have a role in the treatment protocols of MDR tumors,especially when given as the initial means for inductionof intracellular acidification.     

International spread of major clones of methicillin resistant staphylococcus aureus: nosocomial endemicity of multi locus sequence type 239 in Saudi Arabia and Romania

Phenotypically identified methicillin resistant Staphylococcus aureus (MRSA) strains from several hospitals in Romania and Saudi Arabia (n = 103 and 68, respectively) were confirmed to be MRSA by mecA PCR and PBP-2' based latex agglutination. Subsequently, strains were differentiated at the sub-species level using pulsed field gel electrophoresis (PFGE) of SmaI DNA macro-restriction fragments. Comparison of the PFGE fingerprints identified major clusters of strains, persistently present in the various hospitals. Endemicity of certain strains was identified, amongst others one due to a particularly methicillin resistant type in the burn wound sector of the Romanian hospital. No PFGE-based overlap was found between the Saudi and Romanian strains. However, multi locus sequence typing (MLST), performed for 20% of all strains, revealed that genuine genetic similarity was obscured by the PFGE analysis. In both the Romanian and Saudi hospitals the renowned sequence type (ST) 239 was very over-represented. This was especially apparent in Saudi Arabia, where all strains except two shared the ST 239 genotype. This clonal type has previously been identified in a variety of other countries. Despite the MLST concordance, PFGE data indicate that ST 239 diversifies while maintaining its core genome intact. ST 80, another previously but less frequently identified clone, was introduced in 2000 in the Romanian institutes and persisted over the past 3 years as a frequent cause of infections in a surgical department. The successful MRSA types can acquire prominent positions in hospitals of previously low-endemicity MRSA status.     

利用基因芯片技术研究乌头碱抗KBV200细胞耐药机制

目的采用基因芯片技术研究乌头碱抗KBV200细胞耐药机制。方法提取乌头碱12.5μg/mL用药组和对照组KBV200细胞的RNA,进行cDNA微阵列分析。结果整张基因芯片5504个基因克隆,其中用药前高表达基因208个,占克隆总数的3.8%,用药后高表达基因196个,占3.6%。用药前后细胞凋亡相关基因、CDKS家族、SMADS家族、MAPK信号转导系统等的基因发生变化。结论乌头碱可能通过影响细胞凋亡相关基因和影响MAPK信号转导系统等机制,最后作用于Mdr1基因的表达,从而起到抗耐药作用。     

鲍曼不动杆菌对喹诺酮类耐药机制

目的 探讨鲍曼不动杆菌对氟喹诺酮类药物的耐药机制。方法 采用K-B法检测35株鲍曼不动杆菌对氟喹诺酮类药物的药敏情况。十二烷基磺酸钠一聚丙酰胺凝胶电泳(SDS-PAGE)法检测鲍曼不动杆菌的外膜蛋白(OMP)，直接荧光法检测鲍曼不动杆菌对环丙沙星的吸收和积累，PCR法扩增gyrA基因并对其进行测序。结果 35株鲍曼不动杆菌中有20株对氟喹诺酮类药物耐药，耐药菌株与敏感菌株相比，外膜蛋白在约29Ku条带处消失，在26Ku条带处明显增强。耐药菌株药物积累量不及敏感菌株，经叠氮钠处理后，积累量上升并接近敏感菌株，对PCR扩增产物gyrA测序未发现有突变。结论 鲍曼不动杆菌对氟喹诺酮类药物的耐药与外膜蛋白的低通透性和主动外运有关。     

含环丙沙星及卷曲霉素方案治疗耐多药肺结核近期疗效分析

目的观察和评价含环丙沙星（CPFX）和卷曲霉素（CPM）联合化疗方案在耐多药肺结核（MDR—PTB）治疗中的效果。方法将186例MDR—PTB患者随机分为治疗组92例和对照组94例。化疗方案：治疗组以CPFX和CPM为主，联合利福喷汀、异烟肼对氨基水杨酸钠、吡嗪酰胺；对照组用链霉素、乙胺丁醇，联用药物同治疗组，疗程均为21个月。结果共有170例患者完成化疗疗程，治疗组86例，痰菌阴转率为83％，对照组84例，痰菌阴转率为58％，痰菌阴转率治疗组与对照组比较差异有统计学意义（P〈0．01）；治疗组病灶显著吸收率为50％，空洞闭合率为64％，治疗组与对照组比较差异有统计学意义（P〈0．01或〈0．05）；治疗组的药物不良反应率为32％，对照组为34％，两组比较差异无统计学意义（P〉0．05）。结论含CPFX和CPM的方案治疗MDR—PTB，有助于痰菌阴转和病变吸收好转，药物不良反应低，值得在临床上推广应用。     

不同病区和标本来源金黄色葡萄球菌感染的耐药性监测

目的：了解不同病区和标本中金黄色葡萄球菌的感染情况及其耐药性变化特别是ORSA的耐药情况。方法：应用MicroScan AutoScan-4专用PC12鉴定板检测210例金黄色葡萄球菌对18种的抗生素的敏感程度，根据仪器专家系统自动分析病原菌对抗生素的MIC浓度和β内酰胺酶阳性结果。结果：所有金黄色葡萄球菌菌株β内酰胺酶阳性，OR-SA菌株以白带最高（85．7％）、其次为精液（76．4％）、尿液（55．0％），伤口分泌物（31．2％）和脓液（5．3％）最低，门诊（标本主要为白带、精液等）、一般住院病人、ICU中ORSA菌株分离率分别为79．6、41．9、25．0％；ORSA菌株对氨苄西林、青霉素G耐药率99．2％，苯唑西林敏感金黄色葡萄球菌（OSSA）对氨苄西林、青霉素G耐药率也超过83．0％；ORSA菌株对诺氟沙星、环丙沙星、红霉素、克林霉素、庆大霉素等多种抗生素的耐药性高于OSSA菌株（P〈0．001），并有耐万古霉素菌株的出现；不同病区来源的金黄色葡萄球菌对环丙沙星、红霉素、诺氟沙星、四环素、苯唑西林耐药率高低出现门诊、一般住院病人、ICU依次递减的现象（P〈0．05）；来自精液、痰液标本的金黄色葡萄球菌对环丙沙星、庆大霉素、苯唑西林的耐药率和白带标本中金黄色葡萄球菌对苯唑西林的耐药率明显高于脓液（P〈0．05）。结论：来自社区感染金黄色葡萄球菌高ORSA分离率与标本来源有关，不同标本之间抗生素的敏感性存在差异性，ORSA与OSSA对抗生素耐药性不同。     

肥胖和肥胖抵抗大鼠神经肽Y及其受体基因表达的研究

目的:探讨高脂饲料对大鼠下丘脑神经肽Y(NPY)及其受体Y1、Y2、Y5基因表达的影响及大鼠肥胖易感性差异的机制。方法:36只雌性SD大鼠,按体重随机分为高脂组和对照组,分别给予高脂饲料和基础饲料13w。实验结束时,根据体重将高脂组分为饮食诱导肥胖(DIO)和肥胖抵抗(DIO-R)大鼠,观察各组大鼠体重、内脏脂肪湿重、脂体比、热能摄入量及能量利用率的差异;RT-PCR法测定下丘脑NPY及其受体Y1、Y2、Y5mRNA的表达水平。结果:DIO大鼠体重、内脏脂肪湿重、脂体比、热能摄入量及能量利用率显著高于对照组和DIO-R大鼠,而DIO-R大鼠与对照组相比未见显著性差异;DIO大鼠下丘脑NPY及其受体Y1、Y2、Y5mRNA的表达水平显著高于对照组和DIO-R大鼠,而DIO-R大鼠与对照组相比,除Y2受体mRNA的表达水平显著下降外,其余指标均无显著性差异。结论:高脂饲料诱导下,SD大鼠表现为明显的肥胖易感性差异,下丘脑NPY及其受体的高水平表达可能是导致DIO大鼠热能摄入过多的内在机制之一。     

肺炎链球菌对大环内酯类抗生素耐药机制研究

目的观察耐大环内酯类肺炎链球菌的耐药表型和基因型。方法用琼脂二倍稀释法测定耐大环内酯类肺炎链球菌对11种抗生素的最低抑菌浓度,耐药表型由红霉素和克林霉素双纸片法初步分型,通过PCR扩增耐药基因ermB和mefA进行基因分型,并测定ermB和mefA基因序列。结果　所有23株肺炎链球菌对大环内酯和克林霉素高度耐药,均表现为内在型耐药,没有发现诱导型耐药和M型耐药。ermB基因在23株肺炎链球菌中均检测到,其中5株同时检测到mefA基因,没有发现仅单一mefA基因阳性的菌株,基因型与耐药表型完全一致。所测ermB和mefA基因序列与基因库收录序列高度一致。 结论ermB基因介导的靶位改变可能是重庆地区肺炎链球菌对大环内酯类抗生素的主要耐药机制。