靶向CXCR1基因的shRNA真核表达质粒的构建及鉴定

目的：构建靶向化学趋化因子受体1（CXCR1）的短发夹小干扰RNA（shRNA）质粒表达载体。方法：针对人CXCR1基因的mRNA序列,按RNA干扰靶位点的设计原则,设计并构建靶向CXCR1基因的3个shRNA质粒表达载体和1个阴性对照质粒表达载体,经酶切和测序确认构建成功后,转染胃癌细胞MKN45,RT-PCR和Western blot检测CXCR1 mRNA和蛋白的表达。结果：经酶切和测序证实,3个靶向CXCR1基因的shRNA真核表达质粒均构建成功;与未转染和转染阴性对照质粒的MKN45细胞比较,转染3种shRNA质粒的MKN45细胞,CXCR1 mRNA和蛋白水平均明显下调（均P<0.05）。结论：靶向CXCR1基因的shRNA真核表达质粒的成功构建,为进一步研究CXCR1在胃癌中的功能和实验性靶向治疗提供了初步的基础。

     

RNAi靶向抑制suvivinn基因对膀胱癌EJ细胞凋亡和细胞周期的影响

用真核转录载体pSilencer 2.0.U6在膀胱癌细胞系EJ细胞内表达针对Survivin基因的短发卡状RNA(shRNA),以阻断细胞中Survivin基因的表达,观察Survivin基因沉默后对EJ细胞凋亡、细胞周期产生的影响.     

Survivin在紫杉醇介导MCF-7细胞凋亡中的作用

目的 观察紫杉醇对人乳腺癌细胞株MCF-7的凋亡诱导作用，探讨Survivin在此过程中的作用。方法 将不同浓度的紫杉醇作用于MCF-7细胞，噻唑蓝（MTT）比色法检测紫杉醇作用的时间效应和剂量效应；用光镜、Hoechst33258荧光染色、流式细胞仪观察细胞的凋亡变化；用逆转录一聚合酶链反应（RT-PCR）、Western blot法观察在紫杉醇作用过程中Survivin的mRNA和蛋白水平的变化。结果 细胞生长抑制率呈现一定的时间、剂量依赖性。较高浓度的紫杉醇处理MCF-7细胞48h后可观察到凋亡。而在各种浓度紫杉醇作用过程的早期（6h内），Survivin转录和蛋白表达水平明显—过性升高。结论 紫杉醇可诱导乳腺癌MCF-7细胞凋亡；而紫杉醇作用过程的早期Survivin表达的增加，极可能有利于肿瘤细胞逃避紫杉醇诱导的细胞凋亡，增加肿瘤细胞耐药的机会。     

短发卡状RNA特异性抑制表皮生长因子受体对大肠癌细胞凋亡的影响

目的体外构建编码人类表皮生长因子受体(EGFR)的短发卡状RNA(shRNA)的质粒表达载体,观察其对结肠癌LoVo细胞EGFR的特异性抑制作用以及对细胞凋亡的影响。方法体外合成EGFR的DNA模板引物和Pgenesil-1质粒构建编码shRNA的表达载体。应用脂质体Lipofectamine2000转染人结肠癌LoVo细胞,转染成功后以G418筛选4周,实时荧光定量RT-PCR(realtime RT-PCR)和Western-blot检测EGFR的表达,流式细胞仪检测细胞凋亡。结果成功的构建了针对EGFR的质粒表达载体。质粒载体成功转染后,EGFR mRNA表达下降了(81.3±2.8)%,蛋白表达下降了(73.4±2.3)%,细胞凋亡增加了(10.1±0.4)%,和对照质粒载体比较差异有统计学意义。结论我们构建的针对EGFR的质粒表达载体可以显著抑制其在人结肠癌LoVo细胞的表达,诱导细胞凋亡,为结肠癌的基因治疗提供了新的思路。     

靶向survivin的shRNA对人胆管癌细胞体外增殖及凋亡的影响

目的：探讨靶向survivin的shRNA对人胆管癌细胞体外增殖及凋亡的影响。方法：合成具有互补序列的能够编码短发卡RNA（shRNA）的双链寡核苷酸并构建pSilencer2．1真核表达质粒,经稳定转染QBC939细胞后对转基因后胆管癌细胞的生物学行为进行观察。结果：neo基因稳定表达于转染阳性质粒及阴性对照质粒的QBC939细胞中。通过RT—PCR及westernblot检测证实shRNA在mRNA及蛋白质水平抑制survivin表达率分别达68固％和613％。细胞计数及平板克隆形成实验显示转染细胞生长速度及细胞克隆明显减缓（P〈O．01）。流式细胞术测定细胞周期显示转染细胞G1期细胞明显增多,S期细胞明显减少。DNAladder、透射电镜观察及流式细胞定量研究显示转染细胞凋亡明显增多。结论：靶向survivin的shRNA能有效抑制目的基因的表达,通过增加细胞凋亡在体外抑制人胆管癌细胞的生长,为胆管癌的基因治疗提供一定的实验基础。     

RNA干扰双位点抑制Survivin基因诱导雄激素非依赖性前列腺癌PC-3细胞凋亡

目的研究采用RNA干扰技术抑制雄激素非依赖性前列腺癌PC-3细胞中Survivin 基因的表达对PC-3细胞增殖及凋亡的影响。方法设计2条靶向Survivin mRNA的Survivin shRNA,克隆至同一质粒载体,并鉴定分析;质粒转染PC-3细胞,绘制细胞生长曲线;并于转染48 h 后进行Survivin基因蛋白表达及细胞凋亡检测。结果酶切鉴定、测序分析证实负载双片段Sur- vivin shRNA的质粒载体构建成功。转染PC-3细胞后,细胞生长曲线示实验组PC-3细胞增殖明显受抑制;转染后48 h．实验组、阴性对照组、空白对照组Survivin蛋白表达强度分别为(4．62± O．84)％、(38．83±7．96)％和(40．98±3．83)％,实验组与两对照组相比差异均有显著性意义(P< 0．05);转染48 h后PC-3细胞凋亡率开始增加。结论负载双片段Survivin shRNA的质粒载体转染PC-3细胞后能明显抑制PC-3细胞增殖,抑制PC-3细胞Survivin蛋白表达,并能诱导PC-3细胞凋亡。但诱导PC-3细胞凋亡最明显的时机需要进一步观察。     

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。     

短发夹RNA干扰表达质粒逆转人大肠癌细胞LOVO／5-Fu多药耐药的研究

目的：探讨短发夹RNA（shRNA）沉默多药耐药MDR）基因对大肠癌多药耐药细胞株LO-VO/5-Fu生长的影响。方法：构建靶向MDR1的shRNA干扰质粒转染人大肠癌多药耐药细胞株LO-VO/5-Fu,MTT法检测各组细胞对5-Fu的敏感性,流式细胞术检测细胞周期变化、凋亡情况及P-糖蛋白（P-gp）的表达,Realtime-PCR检测各组细胞MDR1 mRNA表达的变化,Western blot检测各组细胞P-gp表达的变化。结果：与对照组质粒组和未转染组相比,转染含shRNA干扰质粒细胞的实验组IC50明显降低,为（2.304±0.232）μmol/L,且差异有统计学意义（P〈0.05）,敏感性的相对逆转率为73.8%;凋亡率明显升高为（5.767±0.694）%（P〈0.05）;MDR1 mRNA表达明显下调（P〈0.05）;P-gp的表达水平降低（P〈0.05）。结论：靶向MDR1的shRNA干扰质粒有效抑制了MDR1的表达,使P-gp的表达降低,从而增强了LOVO/5-Fu细胞对5-Fu的敏感性,有可能为临床上克服大肠癌化疗过程中出现的耐药提供新的作用靶点和治疗途径。     

靶向Survivin基因的短发卡RNA对U251细胞生长和凋亡的影响

目的观察Survivin基因特异性短发卡RNA（shRNA）对人脑胶质母细胞瘤U251细胞体外生长和细胞凋亡的影响。方法对U251细胞，稳定转染Survivin基因shRNA真核表达载体pWH1-SR的U251-SR细胞，以及稳定转染空载体pWH1的U251-P细胞。分别采用细胞计数法绘制生长曲线和平板克隆形成实验观察各组细胞的体外生长情况；采用流式细胞术（FCM）定量测定各组细胞的细胞周期和凋亡细胞数量；采用HE染色、Hoechst染色和原位末端标记（TUNEL）方法观察各组细胞形态学特征。结果与U251和U251-P细胞相比，U251-SR细胞生长明显减缓（P〈0．01），细胞克隆形成明显减少（P〈0．01）；U251-SR细胞G1期细胞增多，S期细胞减少，凋亡细胞增加至20．9％，并呈现典型的细胞凋亡形态学改变。结论靶向Survivin基因的特异性shRNA能够在体外明显抑制U251细胞的生长并诱导其发生大量凋亡。     

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 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.     

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.     

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.     

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.     

Synergistic interaction between the effects of propofol and midazolam with fentanyl on phrenic nerve activity in rabbits

Background: It has been shown that the depressive effects of both propofol and midazolam on consciousness are synergistic with opioids, but the nature of their interactions on other physiological systems, e. g. respiration, has not been fully investigated. The present study examined the effect of propofol and midazolam alone and in combination with fentanyl on phrenic nerve activity (PNA) and whether such interactions are additive or synergistic. Methods: PNA was recorded in 27 anaesthetised and artificially ventilated rabbits. In three groups, propofol, fentanyl and midazolam were administered intravenously in incremental doses to construct dose-response curves for the depressant effects of each one on PNA. In another two groups, the effect of pretreatment with either fentanyl 1 μg · kg^?1 i. v. or midazolam 0.05 mg · kg^?1 i. v. on the effects of propofol and fentanyl respectively on PNA were studied. Results: Propofol and fentanyl caused a dose-dependent depression of PNA with complete abolition at the highest total doses of 16 mg · kg^?1 i. v. and 32 μg · kg^?1 i. v., respectively. In contrast, midazolam in incremental doses to a total of 0.8 mg · kg^?1 reduced mean PNA by 63%, but approximately 12% of PNA remained at a total dose as high as 6.4 mg · kg^?1. The mean ED₅₀s, calculated from dose-response curves, were 5.4 mg · kg^?1, 3.9 μg · kg^?1 and 0.4 mg · kg^?1 for propofol, fentanyl and midazolam, respectively. Initial doses of either fentanyl 1 μg · kg^?1 i. v. or midazolam 0.05 mg · kg^?1 i. v. acted synergistically with subsequent doses of either propofol or fentanyl to abolish PNA at total doses of 8 mg · kg^?1 and 8 μg · kg^?1, respectively. Conclusion: Fentanyl has a synergistic interaction with both propofol and midazolam on PNA and hence potentially on respiration.     

Influence of dopexamine hydrochloride on haemodynamics and regulators of circulation in patients undergoing major abdominal surgery

Background: Catecholaminergic support is often used to improve haemodynamics in patients undergoing major abdominal surgery. Dopexamine is a synthetic vasoactive catecholamine with beneficial microcirculatory properties. Methods: The influence of perioperative administration of dopexamine on cardiorespiratory data and important regulators of macro- and microcirculation were studied in 30 patients undergoing Whipple pancreaticduodenectomy. The patients received randomized and blinded either 2 μg · kg^?1 · min^?1 of dopexamine (n=15) or placebo (n=15, control group). The infusion was started after induction of anaesthesia and continued until the morning of the first postoperative day. Endothelin-1 (ET-1), vasopressin, atrial natriuretic peptide (ANP), and catecholamine plasma levels were measured from arterial blood samples. Measurements were carried out after induction of anaesthesia, 2 h after onset of surgery, at the end of surgery, 2 h after surgery, and on the morning of the first postoperative day. Results: Cardiac index (CI) increased significantly in the dopexamine group (from 2.61±0.41 to 4.57±0.78 1 · min^?1 · m^?2) and remained elevated until the morning of the first postoperative day. Oxygen delivery index (DO₂I) and oxygen consumption index (VO₂I) were also significantly increased in the dopexamine group (DO₂I: from 416±91 to 717±110 ml/m² · m²; VO₂I: from 98±25 to 157±22 ml/m² · m²), being significantly higher than in the control group. pHi remained stable only in the dopexamine patients, indicating adequate splanchnic perfusion. Vasopressive regulators of circulation increased significantly only in the untreated control patients (vasopressin: from 4.37±1.1 to 35.9±12.1 pg/ml; ET-1: from 2.88±0.91 to 6.91±1.20 pg/ml). Conclusion: Patients undergoing major abdominal surgery may profit from prophylactic perioperative administration of dopexamine hydrochloride in the form of improved haemodynamics and oxygenation as well as beneficial influence on important regulators of organ blood flow.     

Systemic analgesia adapted to the children's condition

A concept of balanced analgesia using nonsteroidal anti-inflammatory drugs (NSAIDs), paracetamol (acetaminophen), opioids, and corticosteroids can also be used in patients with pre-existing illnesses. NSAIDs are the most effective treatment for acute pain of moderate intensity in children; however, these drugs should be avoided in patients at increased risk for serious side effects, e.g. patients with renal impairment, bleeding tendency, or extreme prematurity. NSAIDs can be given with minimal risks to the younger child with mild to moderate asthma, and, in these patients, the use of steroids can be encouraged; in addition to their antiemetic and analgesic action, a beneficial effect on asthma symptoms can be expected. In the non-intubated child with cerebral trauma, exaggerated sedation caused by opioids and increased bleeding tendency caused by NSAIDs must be avoided. In neonates and small infants, the oral administration of sucrose or glucose is helpful to minimize pain reaction during short uncomfortable interventions.     

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.