TSA抑制人胰腺癌PANC1细胞生长的实验研究

目的研究去乙酰化转移酶抑制剂TSA对人胰腺癌PANC-1细胞生长的影响及其作用机制。方法用不同浓度的TSA处理PANC-1细胞。MTT法检测肿瘤细胞的增殖;流式细胞仪分析细胞凋亡及细胞周期;Western免疫印迹及荧光定量RT-PCR分析抗凋亡基因bcl-2和肿瘤抑制基因p21WAF1/CIP1的表达。结果TSA作用于PANC-1细胞能明显抑制细胞的增殖,且具有明显的剂量依赖性;TSA处理72 h的PANC-1细胞其早期凋亡率明显提高(P0.05),G0/G1期细胞比例显著升高(P0.05),S期细胞比例显著降低(P0.05)。TSA在转录和翻译水平上能明显下调bcl-2的表达(P0.05),上调p21WAF1/CIP1的表达(P0.05)。结论TSA可以通过诱导胰腺癌细胞的凋亡和周期阻滞而抑制癌细胞生长;其发生机制可能与下调抗凋亡基因bcl-2和上调肿瘤抑制基因p21WAF1/CIP1的表达有关。     

TWEAK/Fn14通路在胰腺癌细胞增殖中的作用研究

目的将构建的Fn14短发夹RNA(short hairpin RNA,shRNA)转染胰腺癌PANC-1细胞并检测接种转染的癌细胞增殖情况,分析探讨肿瘤坏死因子相关弱诱导细胞凋亡/成纤维细胞生长因子诱导因子14(TNFrelated weak inducer of apoptosis/fibroblast growth Factor-inducible 14,TWEAK/Fn14)在胰腺癌细胞增殖过程中的作用。方法构建靶向Fn14基因的shRNA并转染胰腺癌PANC-1细胞来特异性沉默Fn14基因的表达。采用流式细胞术及免疫荧光法检测shRNA干扰序列对Fn14表达的影响;采用CCK-8法检测阻断TWEAK/Fn14信号通路后PANC-1肿瘤细胞增殖情况;采用Western blotting法检测阻断TWEAK/Fn14信号通路后下游因子核因子κB(nuclear factor-κB,NF-κB)、TWEAK及半胱氨酸天冬氨酸蛋白酶-3(caspase-3)蛋白表达的影响来进一步探索该信号通路的作用机制。结果转染Fn14 shRNA 24 h后,PANC-1肿瘤细胞的吸光度值(A值)显著低于对照组(P0.000 1);质粒转染后PANC-1细胞的NF-κB、TWEAK及caspase-3蛋白表达量也明显低于对照组(P0.05);且抑制TWEAK/Fn14信号通路后PANC-1细胞的凋亡增加。结论 TWEAK/Fn14参与了胰腺癌的发生发展过程。TWEAK/Fn14可影响胰腺癌肿瘤细胞的凋亡。     

RNA干扰下调NF-κB p65基因表达诱导胰腺癌细胞株PANC-1的凋亡

目的运用RNA干扰（RNA interference，RNAi）技术下调胰腺癌细胞株PANC-1中NF-κB p65基因表达，并评价其对肿瘤细胞凋亡的影响。方法利用阳离子脂质体Lipofectamine^TM 2000将化学合成的人NF-κB p65的小干扰RNA（small interference RNA，siRNA）转染入胰腺癌细胞株PANC-1中。采用RT-PCR法测定细胞内NF-κB p65mRNA的表达，酶联免疫吸附测定法（ELISA）检测NF-κB亚单位p65的DNA结合活性的改变，运用Hoechst33258核染色、流式细胞仪和透射电子显微镜检测p65基因表达下调对PANC-1细胞凋亡的影响。结果化学合成的人NF-κB p65 siRNA能有效地抑制PANC-1细胞中NF-κB p65mRNA的表达（P〈0．01），同时ELISA结果显示，RelA siRNA组的p65亚单位与DNA结合活性明显低于对照组（P〈0．05）。Hoechst33258核染色、流式细胞仪和透射电子显微镜检测发现下调p65基因表达能够诱导PANC-1细胞的凋亡。结论体外实验初步证明了NF-κB p65基因在胰腺癌细胞凋亡调控方面扮演重要角色．通过沉默其表达可诱导胰腺癌细胞的凋亡．     

bcl-2 mRNA、baX mRNA表达在三氧化二砷诱导肝癌细胞凋亡中的意义

目的 分析三氧化二砷(As2O3)诱导肝癌细胞凋亡中凋亡相关基因bcl—2 mRNA、bax mRNA表达的意义。方法 采用电镜、流式细胞仪、电泳及半定量RT—PCR方法检测不同剂量三氧化二砷诱导人肝癌细胞株bel—7402后凋亡的出现及bcl-2mRNA、bax mRNA的表达。结果 0．5にmol/L As2O3处理肝癌细胞未见凋亡，8μmol/L As2O3诱导肝癌细胞出现明显凋亡。对照组和药物组未检测到bcl-2 mRNA的表达，随浓度增加，bax mRNA的表达上调。结论 As2O3通过诱导凋亡抑制肝癌细胞株bel-7402的增殖，凋亡诱导基因bax mRNA的表达上调与此过程有关。bcl—2mR—NA表达与此过程无关。     

特异性阻断Hedgehog信号通路对胰腺癌细胞凋亡的影响及分子机制

目的 观察特异性阻断Hedgehog信号通路对人胰腺癌Mia PaCa-2细胞凋亡的影响,探讨其可能的分子机制.方法 应用特异性Hedgehog通路阻断剂KAAD-eyelopamine阻断Mia PaCa-2细胞的Hedgehog信号通路,噻唑蓝(MTT)法检测阻断Hedgehog信号通路对胰腺癌细胞生长情况的影响;流式细胞技术观察细胞凋亡的变化;Western blot方法检测bax和bcl-2表达的变化.结果 KAAD-cyclopamine明显抑制胰腺癌Mia PaCa-2细胞生长,其作用呈剂量依赖性;阻断Hedgehog信号通路后,胰腺癌细胞凋亡显著增加,细胞中bax表达水平上调,bcl-2表达水平明显下调.结论 特异性阻断Hedgehog信号通路使胰腺癌细胞生长抑制,凋亡明显增加,其机制可能为通过上调bax及下调bcl-2的表达水平实现.     

胰腺癌细胞凋亡与bcl-2,bax基因的表达

目的探讨胰腺癌组织中的bcl-2和bax的表达及bcl-2/bax比值与胰腺癌细胞凋亡的关系.方法对30例胰腺癌标本应用免疫组化SP方法测定胰腺癌切片中的凋亡抑制基因bcl-2和凋亡促进基因bax的表达;同时应用TUNEL法测定胰腺癌细胞原位凋亡情况.结果高分化腺癌的凋亡指数(AI)为(5.70±1.21)%;中低分化腺癌为(6.80±2.01)%.AI与bcl-2/bax比值呈负相关关系(r=- 0.5583,P<0.05 ).结论 bcl-2和bax在胰腺癌细胞凋亡调节过程中起着重要作用.     

长链非编码RNA WAC-AS1在胰腺癌中的临床意义及分子机制验证

目的探索长链非编码RNA(lncRNA) WAC-AS1在胰腺癌中的生物学功能和作用机制以及对胰腺癌预后的影响。方法基于在线数据库计算并分析WAC-AS1在胰腺癌组织中相对正常组织的表达以及与其预后、肿瘤微环境、免疫细胞浸润的关系。同时应用基因集差异分析(GSVA)以及基因集富集分析(GSEA)探讨了WAC-AS1在胰腺癌中的生物学作用以及参与的信号通路。构建质粒转染人胰腺癌PANC-1细胞系, 分成空载对照组、低表达组、中表达和高表达组, 细胞计数试剂盒(CCK-8)实验检测WAC-AS1对胰腺癌细胞的增殖影响, 蛋白质印迹法(Western blot)检测WAC-AS1过表达后B细胞淋巴瘤/白血病-2(bcl-2)、bcl-2相关X蛋白(bax)和细胞周期蛋白(Cyclin) D1的变化, 组间比较采用t检验。结果 lncRNA WAC-AS1在胰腺癌组织中(P<0.01)相对正常组织呈明显高表达。在胰腺癌中, WAC-AS1主要影响患者的总体生存期以及无进展生存期[P<0.01, 风险比(HR)=0.559, 95%可信区间(CI):0.368～0.848;P<...     

重复加热对肝癌HepG2细胞增殖周期及bcl-2的影响

目的探讨多次热疗后残存的肝癌HepG2细胞增殖速度变化及其相关的可能原因。方法HepG2细胞43℃加热，每次80min，2次／d，10个循环，分析细胞倍增时间，检测细胞周期及bcl-2 mRNA及bax mRNA的表达。结果热处理后的HepG2细胞增殖加快，细胞周期中G2期和S期细胞的比率增高，bcl-2 mRNA的表达增强，bcl-2／bax比值增大。结论热处理后的HepG2细胞的增殖加快与其完成DNA复制而进入分裂的细胞比率高、抗凋亡基因bcl-2mRNA的强表达及bcl-2／bax比值的增加有关。     

miR-7-5p抑制胰腺癌细胞放疗后加速再增殖的体外实验研究

目的 研究放疗后濒死胰腺癌细胞（PANC-1）释放的微小RNA-7-5p（miR-7-5p）对存活PANC-1加速再增殖效应的相关机制。方法 通过慢病毒感染,建立荧光素酶标记的PANC-1-LUC胰腺癌细胞放疗后加速再增殖模型。通过RT-qPCR检测miRNA-7-5p的表达水平,流式细胞仪检测细胞周期及凋亡,双荧光素酶法验证miR-7-5p靶基因,Western blotting检测γH2A.X与DDIT4 蛋白的表达情况。结果 miR-7-5p在受辐照PANC-1（10 Gy）濒死细胞上清中表达下调,受辐照PANC-1细胞与存活PANC-1-LUC细胞共培养,可促进放疗后存活PANC-1-LUC细胞加速再增殖及其DNA损伤修复,而上调miR-7-5p可抑制放疗后胰腺癌细胞PANC-1-LUC再增殖。进一步研究表明,miR-7-5p在胰腺癌细胞中通过靶向下调DDIT4通路促进凋亡信号。结论 受辐照胰腺癌细胞可通过下调miR-7-5p促进DDIT4表达,从而抑制细胞凋亡及调控细胞周期再分布来加速再增殖,表明提高miR-7-5p的水平能够提高胰腺癌细胞的放疗敏感性,这将为改善胰腺癌放疗抵抗提供了一种新的思路和方法。     

肿瘤相关巨噬细胞通过PI3K/Akt途径促进胰腺癌浸润迁移的研究

目的研究PI3K/Akt信号通路对胰腺癌细胞PANC-1浸润迁移能力的影响,进一步探讨肿瘤相关巨噬细胞促进胰腺癌发生发展的分子机制。 方法通过密度梯度离心法从健康成人外周血中分离单个核细胞,用IL-4体外诱导选择性激活的巨噬细胞(M2)。采用实时荧光定量PCR和Western blotting法检测胰腺癌PANC-1细胞PI3K、Akt mRNA和蛋白表达水平的变化,利用Transwell侵袭实验与划痕实验观察细胞浸润迁移能力的变化。 结果体外模拟胰腺癌微环境,将胰腺癌PANC-1细胞与不同激活状态的巨噬细胞共培养,证明M2可显著上调胰腺癌PANC-1细胞PI3K、Akt的mRNA和蛋白水平,共培养20 h后可明显促进胰腺癌PANC-1细胞的浸润与迁移能力。 结论肿瘤相关巨噬细胞可通过PI3K/Akt信号通路促进胰腺癌细胞的浸润与迁移。     

Vasopressor hormone response following mesenteric traction during major abdominal surgery

Background : We investigated the vasopressor hormone response following mesenteric traction (MT) with hypotension due to prostacyclin (PGI₂) release in patients undergoing abdominal surgery with a combined general and epidural anesthesia. Methods : In a prospective, randomized, placebo-controlled study we administered 400 mg ibuprofen (i.v.) in 42 patients scheduled for abdominal surgery. General anesthesia was combined with epidural anesthesia (T4-L1). Before as well as 5, 15, 30, 45, and 90 min after MT we recorded plasma osmolality, hemodynamics and measured 6-keto-PGFlα (stabile metabolite of PGI₂), TXB₂ (stabile metabolite of thromboxane A₂) active renin, and arginine vasopressin (AVP) plasma concentrations by radioimmunoassay. Catecholamine levels were assessed by high-pressure liquid chromatography (HPLC) with electrochemical detection. Results : Following MT, arterial hypotension occurred along with a substantial PGI₂ release. This was completely abolished by ibuprofen administration. Although plasma levels of 6-keto-PGF_1α (1133 (708) vs. 60 (3) ng/L, median (median absolute deviation), P=0.0001, placebo vs. ibuprofen) remained significantly elevated, blood pressure was restored within 30 min after MT in the placebo group. At the same point in time plasma concentrations of TXB² (164 (87) vs. 58 (1) ng/L, P=0.0001), epinephrine (46 (33) vs. 14 (6) ng/L, P=0.001), AVP (41 ± (18) vs. 12 (7) ng/L, P=0.0004), and active renin (27 (12) vs. 12 (4) ng/L, P = 0.001) were significantly higher in placebo-treated patients. Conclusion : Under combined general and epidural anesthesia arterial hypotension following MT due to endogenous PGI₂ release is associated with enhanced release of AVP, active renin, epinephrine and thromboxane A₂, presumably contributing to hemodynamic stability within 30 min after MT.     

A comparison of the inhibitory effects of four volatile anaesthetics on the metabolism of chlorzoxazone, a substrate for CYP2E1, in rabbits

Background: Halothane inhibits in vitro and in vivo activity of cytochrome P-450 (CYP) 2E1. There are several fluorinated volatile anaesthetics besides halothane, and most of them are defluorinated by CYP2E1. It is unclear whether other fluorinated anaesthetics inhibit the in vivo activity of CYP2E1.
Methods: We compared the inhibitory effects of therapeutic concentrations of four inhalational anaesthetics, halothane, enflurane, isoflurane, and sevoflurane, on chlorzoxazone metabolism in rabbits receiving artificial ventilation.
Results: All four inhalational anaesthetics decreased arterial blood pressure and increased plasma chlorzoxazone concentration. However, no significant differences in the plasma chlorzoxazone concentration were found between the four anaesthetics. The estimated chlorzoxazone clearance increased after beginning inhalation with all four agents, but no significant difference in clearance was noted between agents.
Conclusions: At therapeutic concentrations, the in vivo inhibitory effect on chlorzoxazone metabolism was similar for all four inhalational anaesthetics examined, even though their chemical characteristics and extent of hepatic metabolism differ considerably.     

A Teaspoon Pump for Pumping Blood with High Hydraulic Efficiency and Low Hemolysis Potential

Abstract: Virtually all blood pumps contain some kind of rubbing, sliding, closely moving machinery surfaces that are exposed to the blood being pumped. These valves, internal bearings, magnetic bearing position sensors, and shaft seals cause most of the problems with blood pumps. The original teaspoon pump design prevented the rubbing, sliding machinery surfaces from contacting the blood. However, the hydraulic efficiency was low because the blood was able to "slip around" the rotating impeller so that the blood itself never rotated fast enough to develop adequate pressure. An improved teaspoon blood pump has been designed and tested and has shown acceptable hydraulic performance and low hemolysis potential. The new pump uses a nonrotating "swinging" hose as the pump impeller. The fluid enters the pump through the center of the swinging hose; therefore, there can be no fluid slip between the revolving blood and the revolving impeller. The new pump uses an impeller that is comparable to a flexible garden hose. If the free end of the hose were swung around in a circle like half of a jump rope, the fluid inside the hose would rotate and develop pressure even though the hose impeller itself did not "rotate"; therefore, no rotating shaft seal or internal bearings are required.     

Microspheres Based Detoxification System: A New Method in Convective Blood Purification

Abstract: A variety of protein-bound or hydrophobic substances, accumulating as a result of pathologic conditions such as exogenous or endogenous intoxications, are removed poorly by conventional detoxification methods because of low accessibility (hemodialysis), insufficient adsorption capabilities (hemosorption), low efficiency (peritoneal dialysis), or economic limitations (high-volume plasmapheresis). Combining advantages of existing methods with microspheric technology, a module-based system was designed. Major operating parameters of the latter can be modified to allow for adjustment to individual clinical situations. An extracorporeal blood circuit including a plasmafilter is combined with a secondary high-velocity plasma circuit driven by a centrifugal pump. Different microspheric adsorbers can be combined in one circuit or applied in sequence. Thus, a prolonged treatment can be tailored using specially designed selective adsorber materials. Comparing this system with existing methods (high-flux hemodialysis, molecular adsorbent recycling system), results from our in vitro studies and animal experiments demonstrate the superior efficiency of substance removal.     

Is the recovery profile of mivacurium independent of the rate of decay of its plasma concentration in patients with normal plasma cholinesterase activity?

Background: The duration of action of muscle relaxants is poorly correlated to the rate of decay of their plasma concentration. The plasma concentration of mivacurium may rapidly decrease below its active concentration because of the extensive hydrolysis of mivacurium. By inflating a tourniquet on one upper limb for 3 min after the administration of atracurium, mivacurium or vecuronium, we studied the influence of the initial decline of their plasma concentration on their effect. Methods: In 50 patients anaesthetised with thiopental, isoflurane and fentanyl, the effect of bolus doses of 0.15 or 0.25 mg . kg^?1 mivacurium (MIV 15, MIV 25), 0.3 or 0.5 mg . kg^?1 atracurium (ATR 30, ATR 50) and 0.06 or 0.1 mg . kg^?1 vecuronium (VEC 06, VEC 10) were measured on both arms (evoked response of the adductor pollicis to train-of-four stimulation every 12 s), a tourniquet being applied on one arm just before and during 3 min after the muscle relaxant bolus. Results: Tourniquet inflation of 3 min almost abolished the neuromuscular effect of mivacurium. In the vecuronium groups and in the ATR 50 group, tourniquet inflation did not modify the maximum degree of depression of the twitch response. Also, the duration of action of vecuronium was unaffected by the tourniquet. In the ATR 30 group, times to return of the twitch response to 25% (duration 25%) and 75% (duration 75%) of control response were significantly shorter in the cuffed arm, 23 min vs 27 min, and 41 min vs 45 min, respectively. In the ATR 50 group, only duration 25% was significantly shorter in the cuffed arm (41 min vs 45 min). Conclusion: The results suggest that the rate of decline of the plasma concentration of mivacurium is so rapid, that a very low and almost clinically ineffective concentration is present as soon as 3 min after its administration. The results also indicate that the recovery from a mivacurium-induced neuromuscular blockade is not influenced by the rate of decay of its plasma concentration in patients with genotypically normal plasma cholinesterase.     

Membranes in Artificial Organs

Abstract: Membrane processes play a pivotal and enabling role in modern replacement therapy for acute and chronic organ failure and in the management of immunologic diseases. In fact, virtually all contemporary extracorporeal blood purification methods employ membrane devices, and the next generation of artificial organs and tissue engineering therapies are almost certain to be similarly grounded in membrane technology. In this short essay, we comment on the similarities and differences among synthetic membranes and their natural counterparts and also provide a critical overview of the demographics and technology of hemodialysis, hemofiltration, apheresis, oxygenation, and emerging membrane technologies and applications.     

Tissue perfusion in relation to cardiac output during continuous positive-pressure ventilation and administration of propranolol or verapamil

Background : Our objective was to determine whether administration of propranolol or verapamil modifies the hemodynamic adaptation to continuous positive-pressure ventilation (CPPV), in particular the regional distribution of cardiac output (CO).
Methods : General hemodynamics and regional blood flows assessed by microsphere technique (15 (μm) were recorded in 16 anesthetized pigs during spontaneous breathing (SB) and CPPV with 8 cm H₂O end-expiratory pressure (CPPV8) before and after intravenous administration of propranolol (0.3 mg · kg⁻¹ followed by 0.15 mg · kg⁻¹ · h⁻¹, n=8) or verapamil (0.1 mg · kg⁻¹ followed by 0.3 mg · kg⁻¹ · h⁻¹, n=8).
Results : CPPV8 depressed CO by 25% without shifts in its relative distribution with the exception of a noteworthy increase in adrenal perfusion. Propranolol increased arterial blood pressure, and due to a fall in heart rate, CO dropped by 25%. The kidneys and, to a lesser extent, the splanchic region and central nervous system received increased fractions of the remaining CO at the expense of skeletal muscle flow. Similar patterns were seen during SB and CPPV8 such that the combination of propranolol and CPPV8 depressed CO by 50%. The circulatory effects of verapamil were less evident but myocardial perfusion tended to increase.
Conclusions : The combination of propranolol or verapamil with CPPV does not result in any specific hemodynamic interaction in anesthetized pigs, except that the combined effect of propranolol and CPPV may severely reduce CO.     

Volatile anaesthetics reduce adhesion of blood platelets under low-flow conditions in the coronary system of isolated guinea pig hearts

Background : Inhibitory effects of volatile anaesthetics on platelet aggregation have been demonstrated in several studies. However, the influence of volatile anaesthetics on intracoronary platelet adhesion has not been elucidated so far.
Methods : Isolated hearts of guinea pigs were perfused with buffer in the absence or presence of volatile anaesthetics (0.5 and 1 MAC) at constant coronary flow rates of 5 ml/min for 25 min, then 1 ml/min for 30 min and again 5 ml/min for 10 min. Before, during and after low-flow perfusion, a bolus of human platelets was applied into the coronary system. To simulate thrombogenic conditions, 0.3 U/ml human thrombin was infused during low-flow perfusion and reperfusion. The number of platelets sequestered to the endothelium was calculated from the difference between coronary in- and output of platelets. The myocardial production of lactate and consumption of pyruvate and coronary perfusion pressure were also determined.
Results : At a flow rate of 5 ml/min only about 3% of the applied platelets did not emerge from the coronary system, in any group. In contrast, 13.1±1.2% (mean±SEM) of infused platelets became adherent in low-flow perfusion in the control group without anaesthetic. The adherence was reduced with each 1 MAC isoflurane (to 6.2±1.2%), sevoflurane (to 4.4±0.9%) or halothane (to 3.2±1.5%) (each P <0.05 vs. control). Volatile anaesthetic, 0.5 MAC, did not inhibit platelet adhesion to a statistically significant extent in any case. Perfusion pressure and metabolic parameters were not statistically different between the control and the hearts exposed to anaesthetics.
Conclusion : Volatile anaesthetics in a concentration of 1 MAC can reduce the adhesion of platelets in the coronary system under reduced flow conditions. This action does not arise from vasodilation or inhibition of ischaemic stress.     

Bariatric Surgery in Some "Central and East-European (former Eastern bloc)"Countries - Current Status and Prediction for the Next Millennium

Background: Obesity is increasing globallly, including in the formerly "Eastern Bloc" countries. Methods: A survey was made of obesity and bariatric surgery. Results: In the 8 East and Central European countries studied, with total population 300 million, roughly 43% of the population was overweight (BMI 25-30), 23% obese (BMI > 30), with about 15 million people morbidly obese (BMI > 40). From 0-10 morbidly obese individuals/100,000/year undergo bariatric surgery. Conclusion: Most countries were found to provide inadequate treatment for obesity.The majority of the morbidly obese are not treated effectively. However, health-care awareness of obesity and bariatric surgeons are slowly increasing.     

Dilemma of Membrane Biocompatibility and Reuse

Abstract: Numerous articles have been published on the multiple use of dialyzers and on the effect of different reprocessing chemicals and techniques on the dialyzer biocompatibility and performance. The results often appear contradictory, especially those comparing standard biocompatibility parameters. Despite this confusion, a discerning review of the published works allows certain limited conclusions to be drawn. Reprocessing of used hemodialyzers changes the biocompatibility profile of a dialyzer as defined by the parameters complement activation. leukopenia, and cytokine release. The effect of reprocessing depends on the chemicals and reprocessing technique applied and also on the type of membrane polymer being subjected to the reprocessing procedure. Reports of pyrogenic reactions indicate that the flux of the membrane also influences how suitable it is for safe reuse. An increased risk of allergic and pyrogenic reactions appears to be associated with dialyzer reuse. Furthermore, there has been a lack of investigations into the immunologic effect of the layer of adsorbed and chemically altered proteins that remains on the inner surface of reprocessed dialyzers. We conclude that the clinical benefit of dialyzer reuse cannot be generally accepted from a biocompatibility point of view.