DJ-1 shRNA靶向逆转人乳腺癌阿霉素耐药细胞株MCF-7/ADM的耐药性

目的探讨干扰癌基因DJ-1表达对人乳腺癌耐药细胞株MCF-7/ADM多药耐药性(multi-drug resistence,MDR)的影响。方法将构建的DJ-1 shRNA真核表达载体,用脂质体转染至人乳腺癌耐药细胞株MCF-7/ADM;用RT-PCR和Western blot法分别检测细胞MDR 1 mRNA和P-糖蛋白(P-glycopro-tein,P-gp)的表达;MTT法检测细胞对化疗药物的敏感性。结果 DJ-1 shRNA靶向干预MCF-7/ADM细胞DJ-1表达后,DJ-1 shRNA组细胞MDR 1 mRNA和P-gp表达水平较空白与阴性对照组明显下降(P0.0 1);细胞内Adriamycin浓度明显增加;细胞对Adriamycin的敏感性增强2.6 8倍。结论 DJ-1shRNA可降低乳腺癌MCF-7/ADM细胞的MDR,为研究逆转乳腺癌化疗耐药提供了新方法。     

Cdc42在人乳腺癌细胞MCF-7阿霉素敏感株和耐药株中的表达

目的探讨细胞分裂周期蛋白42(Cdc42)在乳腺癌细胞MCF-7阿霉素敏感株和耐药株MCF-7/Adr中表达的变化以及对细胞耐药性的影响。方法将Cdc42 siRNA转染MCF-7/Adr细胞株后,用RT-PCR和Weastern Blot方法检测MCF-7组,MCF-7/Adr组,MCF-7/Adr siRNA干扰组细胞Cdc42的转录以及蛋白的表达水平;采用四甲基偶氮唑蓝(MTT)法测定siRNA处理后阿霉素(ADM)对MCF-7/Adr细胞的杀伤作用;用荧光分光光度计测定细胞内ADM药物浓度。结果 MCF-7/Adr细胞中Cdc42 mRNA及蛋白表达量显著高于MCF-7细胞(P0.05);siRNA干扰后Cdc42表达受到明显抑制(P0.05),并显著提高细胞内ADM的浓度(P0.05)。结论特异性siRNA能明显抑制Cdc42 mR-NA及蛋白表达,并逆转细胞耐药性。     

葡萄籽多酚逆转胆囊癌细胞株GBC-SD耐药的研究

目的研究葡萄籽多酚（GSP）逆转先天性耐药细胞株GBC-SD耐药的机制，寻找高效低毒的耐药逆转剂。方法选择先天性耐药细胞株GBC-SD为研究对象。MTT比色法测定各化疗药物的半数抑制浓度（IC50）；RT-PCR测定MDR1 mRNA的变化；流式细胞仪检测P-gP，bcl-2蛋白和细胞内阿霉素浓度的变化。结果（1）无毒（3μg／mL）和低毒（6μg／mL）浓度的GSP处理后各化疗药物的IC50值均明显下降（P〈0．05），能明显逆转GBC-SD的多药耐药性；（2）上述两浓度的GSP能下调GBC-SD细胞MDR1 mRNA表达（P〈0．05）；（3）上述两浓度的GSP能下调GBC-SD细胞P-gP和bcl-2蛋白表达（P〈0．05）；（4）GSP增加GBC-SD细胞内ADM药物浓度（P〈0．05）。结论GSP能部分逆转先天性耐药细胞株GBC-SD多药耐药性，其作用机制为下调GBC-SD细胞MDR1 mRNA，及P-gP和bcl-2蛋白表达。     

多药耐药相关基因及其蛋白在介导胰腺癌细胞原发性耐药中的作用及调控

目的 检测多药耐药相关基因（MDR1）及其蛋白（P-gP）在胰腺癌细胞株的表达,初步探讨胰腺癌发生先天性耐药的机理。方法 选择8株人胰腺癌细胞株,采用RT-PCR方法检测MDR1mRNA在胰腺癌细胞中的表达;通过免疫细胞化学方法检测P-gP的表达;以流式细胞仪检测胰腺癌细胞对罗丹明的外排情况,评价P-gP泵功能;最后通过P-gP抑制物维拉帕米与化疗药物联合应用,检测其对胰腺癌细胞的杀伤作用。结果 MDR1mRNA在胰腺癌细胞株SW1990中的表达最高,除PCT-2未检测到MDR1的表达外,其余6株细胞均有MDR1的微弱表达;免疫细胞化学染色结果证实P-gP在SW1990中的表达明显高于其他细胞株。57．9％±5．4％的SW1990细胞内有罗丹明蓄积,而在P-gP阴性对照细胞中,99．5％±3．3％的细胞内存在罗丹明的积聚,两者差异有统计学意义（P〈0．05）。P-gP抑制物维拉帕米与阿霉素或表阿霉素联合应用时可以部分逆转肿瘤细胞对化疗药物的耐药性。结论 MDR1及P-gP在人胰腺癌细胞中存在一定量的表达;维拉帕米联合阿霉素可以明显抑制P-gP阳性细胞的生长。     

肝细胞癌SMC7721体内外多药耐药模型的建立及其耐药机制

目的 建立肝细胞癌SMC7721体内外多药耐药细胞株并探讨其耐药机制.方法 通过阿霉素浓度递增筛选出SMC7721/ADM肝癌多药耐药细胞株并建立裸鼠移植瘤模型;噻唑蓝(MTr)检测各组移植瘤对化疗药物的耐药性;逆转录-聚合酶链反应(RT-PCR)和Western blot检测MDR1和BCRP在各组移植瘤中的表达.结果 SMC7721/ADM对阿霉素,丝裂霉素,5-Fu的耐药性均较亲本细胞明显降低(P<0.01);其移植瘤对3种化疗药物的IC50.均明显低于亲本细胞(P<0.05);SMC7721/ADM细胞中MDR1 mRNA表达是亲本细胞的40.13倍(P<0.01);BCRP mRNA表达与亲本细胞差异无统计学意义(P>0.05).其移植瘤中BCRP mRNA表达是亲本细胞移植瘤的3.69倍(P<0.01);而MDR1 mRNA表达与亲本细胞差异无统计学意义(P>0.05);SMC7721/ADM细胞株中两种蛋白表达显著高于亲本细胞株(P<0.01);SMC7721/ADM移植瘤中BCRP蛋白表达显著高于亲本移植瘤(P<0.01),而两者中MDR1表达差异无统计学意义(JP>0.05).结论 MDR1和BCRP在SMC7721/ADM多药耐药的不同阶段起作用并介导肝细胞癌对不同药物的耐药性.     

CD326在乳腺癌细胞系的表达及其与乳腺癌细胞耐药的关系

目的 探讨上皮细胞黏附分子(CD326)在乳腺癌细胞系中的表达及其与乳腺癌细胞耐药的关系.方法 流式细胞仪分析MCF-7、MCF-7/ADR及MDA-MB-231中cD326表达情况;细胞计数法(CCK-8法)检测流式细胞仪分选获得的CD326阳性和阴性细胞亚群体外对表阿霉素、多西他赛耐药情况;逆转录-聚合酶链反应(RT-PCR)检测不同细胞亚群中多药耐药基因(MDR1)及乳腺相关耐药基因(BCRP)的表达情况.结果 MCF-7/ADR中CD326的表达(31.03%)明显高于亲本株MCF-7(27.02%),MDA-MB-231中CD326的表达(33.43%)明显高于MCF-7及MCF-7/ADR;MCF-7和MDA-MB-231中CD326阳性细胞亚群对表阿霉素及低浓度多西他赛(0.25～1.0*IC50)的体外耐受性明显高于阴性细胞亚群(P＜0.01),但对高浓度多西他赛(1.5～2.0* IC50)的体外耐受性差异无统计学意义(P＞0.05);CD326阳性与阴性细胞亚群间MDR1、BCRP基因表达差异元统计学意义(P＞0.05).结论 CD326与乳腺癌化疗药物的耐药有关,其诱导耐药并不是通过经典的耐药途径.     

葡萄籽多酚体外逆转胆囊癌细胞株GBC-SD多药耐药作用的研究

目的:研究葡萄籽多酚(GSP)逆转胆囊癌先天性耐药细胞株GBC-SD耐药的作用,寻找高效低毒的耐药逆转剂。方法:选择GBC-SD为研究对象,MTT比色法测定各化疗药物的半数抑制浓度(IC50),RT-PCR测定MDR1mRNA的变化,流式细胞仪检测P-gp蛋白和细胞内阿霉素浓度的变化。结果:①无毒(3μg/ml)和低毒(6μg/ml)剂量浓度的GSP处理后各化疗药物的IC50值均明显降低(P〈0.05),能明显逆转GBC-SD的多药耐药性;②无毒(3μg/ml)和低毒(6μg/ml)剂量浓度的GSP能下调GBC-SD细胞MDR1mRNA表达(P〈0.05);③无毒(3μg/ml)和低毒(6μg/ml)剂量浓度的GSP能下调GBC-SD细胞P-gp蛋白表达(P〈0.05);④GSP增加GBC-SD细胞内ADM药物浓度(P〈0.05)。结论:GSP能部分逆转先天性耐药细胞株GBC-SD多药耐药性,作用机制为下调GBC-SD细胞MDR1mRNA及P-gp蛋白表达。     

腺病毒介导的野生型p53基因逆转乳腺癌耐药细胞株MCF-7/A耐药性的研究

目的 探讨野生型p53基因对乳腺癌耐药细胞株MCF-7/A耐药性的逆转作用及其机制.方法 选用含野生型p53基因的重组腺病毒载体,转染乳腺癌耐药细胞株MCF-7/A,绘制细胞生长曲线,利用流式细胞计数仪检测细胞周期分布及凋亡分析、TUNEL法检测细胞凋亡的发生,并采用逆转录-聚合酶链反应(RT-PCR)和Western blot印迹转移检测p53基因的表达情况.结果 野生型p53基因转染MCF-7/A后的24、48 h均检测到p53基因的表达,并显著抑制MCF-7/A细胞的增殖;细胞周期发生改变,转染后的MCF-7/A的G0%G1期DNA百分含量(76.22%)明显高于对照组(43.64%,P<0.05),凋亡率(10.76%)与对照组(1.48%)之间差异有统计学意义(P<0.05).结论 重组腺病毒介导的野生型p53基因对乳腺癌耐药细胞株MCF-7/A的耐药性有明显的逆转作用,其机制可能是引起明显的G1期阻滞并诱导细胞凋亡.     

中药复方肝癌-1号逆转肝癌多药耐药的实验研究

目的分析中药复方肝癌-1号逆转阿霉素(ADM)诱导的HepG2/ADM细胞的多药耐药性的机制。方法以亲本细胞HepG2为对照,MTT法观察肝癌-1号对HepG2/ADM细胞的毒性作用;流式细胞仪检测肝癌-1号作用后细胞表面p-糖蛋白(P-gp)表达阳性率;逆转录聚合酶链式反应检查多药耐药基因(MDR1)mRNA表达水平;MTT法观察肝癌-1号处理后的HepG2/ADM细胞对阿霉素、表阿霉素、氟尿嘧啶耐药的逆转作用。结果肝癌-1号<50μmol/L对HepG2/ADM细胞无明显毒性,半数抑制率(IC50)为75μmol/L;50μmol/L的肝癌-1号可部分抑制HepG2/ADM细胞P-gp合成及MDR1 mRNA的表达,可逆转HepG2/ADM的耐药性,对阿霉素、表阿霉素、氟尿嘧啶的逆转倍数分别为3.94(P<0.01),1.72(P<0.05),1.67(P<0.05)。结论肝癌-1号通过抑制HepG2/ADM耐药细胞MDR1 mRNA的表达及P-gp合成,能部分逆转HepG2/ADM的耐药性。     

胰腺癌多药耐药细胞株BxPC-3/ADM的建立及耐药机制的初步探讨

目的 构建胰腺癌多药耐药细胞株BxPC-3/ADM,通过动态监测诱导耐药过程,探讨其耐药的可能机制.方法 逐步增加阿霉素浓度对BxPC-3细胞进行诱导,在不同的阿霉素诱导浓度,MTT法检测细胞对多种化疗药物的耐药指数,RT-PCR和Western印迹法检测细胞MDR1和MRP mRNA和蛋白的表达.结果 成功构建多药耐药细胞株BxPC-3/ADM;在0.05 μg/ml至8 μg/ml阿霉素诱导浓度,细胞对5-Fu、MMC和Gem的耐药指数无明显增加;在16 μg/ml浓度3种化疗药物的耐药指数有较明显上升,同时伴有MDR1 mRNA表达的明显增加;至32 μg/ml 5-Fu和Gem的耐药指数未再有继续上升,而MMC的耐药指数则继续上升,同时MDR1 mRNA表达未再增加,而MRP mRNA表达则明显增加.Western印迹实验显示MDR1和MRP蛋白表达变化与mRNA表达变化趋势一致.结论 MDR1基因在诱导早期的耐药中起主导作用,在后期则和MRP基因协同发挥作用.     

Comparison of the haemodynamic actions of desflurane/N2O and isoflurane/N2O anaesthesia in vascular surgical patients

Background: The purpose of this study was to compare heart rate and arterial blood pressure response to desflurane/N₂O vs isoflurane/N₂O anaesthesia in a randomised clinical trial performed in patients before vascular surgery.
Methods: To evaluate associated changes in the autonomic nervous system with maintenance of anaesthesia, we used power spectral analysis (PSA) of heart rate and blood pressure and measured plasma catecholamine concentrations. Twenty-five patients whose trachea had been intubated after propofol induction were given either desflurane or isoflurane at 1 and 1.5 MAC in N₂O (60%) in a random manner.
Results: At an anaesthetic depth of up to 1.5 MAC, arterial blood pressure, indices of sympathetic activity derived from PSA, decreased with both anaesthetics, while heart rate and plasma catecholamine concentrations did not significantly change. Plasma renin activity significantly increased at 1.5 MAC anaesthesia in both groups.
Conclusions: We conclude that sympathetic hyperactivity previously reported during desflurane anaesthesia in healthy volunteers is not frequent in clinical practice in elderly vascular surgical patients under desflurane/N₂O anaesthesia, since it occurs at an anaesthetic depth which cannot be reached in these patients because of the lowering arterial blood pressure effects of desflurane, which are similar to those of isoflurane.     

Principles of CO2/Erbium Laser Safety

BACKGROUND: There are a variety of potential hazards with laser technology. METHODS: A review of the literature. OBJECTIVE: To summarize the potential hazards of CO2 and erbium laser technologies and the safety guidelines and equipment developed to minimize them. RESULTS: Laser hazards can be divided into the following categories: mechanical, environmental, macrobiologic, microbiologic, and iatrogenic. CONCLUSION: At the conclusion of this learning activity, the reader should be able to discuss the mechanical, environmental, macrobiologic, microbiologic, and iatrogenic hazards of resurfacing laser technology, the literature cited to support current safety guidelines, and the equipment developed to promote laser safety.     

Clinical relevance of the B12/N2O interaction A report of a seminar

The interaction of nitrous oxide and vitamin B₁₂ and its implications are not the exclusive territory of any one discipline. The initial discovery was by a chemist but it is of obvious relevance to anaesthetists and intensivists; some complications are neurological others haematological. The interaction provides an extremely important research tool as the first easily available B₁₂-deficient animal model. Finally there are implications for exposure to contaminated atmospheres in hospitals and in industry.     

Acute Xenograft Rejection Mediated by Antibodies Produced Independently of TH1/TH2 Cytokine Profiles

There is substantial support for the hypothesis that T(H)1 cytokine responses are critical for the normal elaboration of allograft rejection. Recent studies by Wang et al. (1) underscore the importance of T(H)2 responses in xenograft rejection and revealed that T(H)1 cytokines, IL-12 and interferon-gamma (IFN-gamma), can negatively regulate the development of humoral responses necessary for xenograft rejection. Their exceptional studies prompted us to test whether the ability of allografts to elicit cellular rejection and xenografts to induce humoral rejection also result from the differential ability to induce T(H)1 and T(H)2 responses. We compared the kinetics of antibody and cytokine (IFN-gamma and IL-4) production in C57BL/6 mice following allograft transplantation with BALB/c hearts and in C57BL/6 and BALB/c mice following transplantation with Lewis rat hearts. We also compared the ability of BALB/c mice, deficient in the ability to produce IL-4 or IFN-gamma, to reject xenografts and produce xenoantibodies. We observed that T(H)1/T(H)2 cytokine production minimally affected the kinetics of graft rejection but regulated the magnitude of IgG subclass production. Anti-graft IgM played a critical role in initiating acute antibody-mediated xenograft rejection, and the production antigraft IgM was unaffected by IL-4 or IFN-gamma deficiency. In contrast to the report by Wang et al. (1), we conclude that antibody-mediated xenograft rejection in the concordant Lewis rat heart-to-C57BL/6 mouse xenotransplantation model is dependent on anti-IgM production but independent of T(H) cytokine profiles.