靶向RNA干扰Survivin对结肠癌细胞HT-29增殖凋亡的影响

目的探讨肿瘤增殖型腺病毒（Ad-delE1b55KD-shRNA／Survivin-EGFP）介导的以人Survivin为靶标的RNA干扰对结肠癌细胞株HT-29中Survivin mRNA和蛋白表达及对HT-29增殖凋亡的影响。方法用Ad-delE1b55KD-shRNA／Survivin-EGFP转染结肠癌细胞株HT-29（以携带相同shRNA的增殖缺陷型腺病毒和脂质体载体为对照），用逆转录-聚合酶链反应（RT-PCR）和Western blot分别检测转染后的HT-29细胞中Survivin mRNA和蛋白表达的变化，用噻唑蓝（MTT）法、吖啶橙／溴乙锭荧光染色法、Annexin V-PE／7-AAD联合染色法检测细胞死亡率及凋亡率。结果与复制缺陷型腺病毒载体和脂质体载体比较，转染Ad-delE1b55KD-shRNA／Survivin-EGFP后，HT-29细胞中Survivin mRNA拷贝数及蛋白表达显著降低，其细胞死亡率和凋亡率显著提高（P〈0．05）。结论Ad-deIE1b55KD-shRNA／Survivin-EGFP介导的RNA干扰较之增殖缺陷型腺病毒载体和脂质体载体具有更高的干扰效率，且能高效地诱导结肠癌细胞凋亡并抑制其增殖。     

反义寡核苷酸抑制Survivin基因表达对移植静脉内膜增生的影响

目的研究反义寡脱氧核苷酸（ASODN）抑制Survivin基因表达对移植静脉内膜增生的抑制作用。方法Wistar大鼠60只，建立自体静脉移植模型，术后随机分为：对照组、Survivin ASODN 50、200μg组、正义对照组、Lipofectin＋pluronic等五个组，施加不同的处理因素，在移植后1、2周取材。组织形态学方法比较内膜增生程度，逆转录．聚合酶链反应（RT-PCR）检测Survivin基因的mRNA表达，Westem blot检测Survivin基因的蛋白产物表达，免疫组织化学方法检测Survivin及增殖细胞核抗原（PCNA）的表达，脱氧核苷酸转移酶末端标记法（TUNEL）检测血管平滑肌细胞（VSMC）凋亡的变化。结果移植后1、2周内膜增生明显，局部转染50μg Survivin ASODN组内膜增生明显受抑制（P〈0．05），200μg组受抑制程度更为明显（P〈0．05）；与对照组相比，Survivln ASODN组Survivin的mRNA及蛋白产物表达显著减少（P〈0．05），PCNA阳性表达同时减少，而TUNEL阳性细胞却明显增加。结论Survivin ASODN可显著抑制移植静脉的内膜增生，其作用可能是通过抑制Survivin基因及其蛋白产物表达，从而抑制VSMC增殖、促进其凋亡而实现的。     

脂质体介导的cFLIP反义寡核苷酸对肾细胞癌的凋亡作用

目的探讨cFLIP反义寡核苷酸（ASODN）对肾细胞癌的抑制作用。方法设计合成cFLIP的ASODN，按不同浓度在脂质体介导下转染786—0肾癌细胞株，设无义（NSODN）和空白对照组进行比较。观察细胞的生长状态，Western blot检测cFLIP蛋白的表达，MTT法检测细胞生长抑制率，应用流式细胞仪检测其凋亡率。结果与NSODN、空白对照组比较，ASODN组cFLIP蛋白表达显著降低（P〈0．05），细胞抑制率（分别为10μmol／L组34．20％，20μmol／L组39．50％）显著增高，上述效应呈浓度依赖性；镜下观察ASODN转染细胞代谢衰退，当转染浓度至20μmol／L时，其凋亡率（56．11％）显著高于空白对照组（7．29％）和NSODN（4．69％）组。结论AS0DN能特异性封闭肾癌细胞cFLIP基因的表达，并可抑制肾癌细胞的增殖，诱导其凋亡。     

生存素反义寡核苷酸对胃癌细胞的抑制作用

目的研究生存素(Survivin)反义寡核苷酸(ASODN)对胃癌细胞系HS746T的抑制作用。方法应用SurvivinASODN转染胃癌细胞,设空白、脂质体和正义链对照组,100、200和400nmol/L反义链组。电镜下观察细胞超微结构,流质细胞术、四甲基偶氮唑盐(MTT)法、逆转录聚合酶链反应(RTPCR)及Westernblot法检测转染后2～48h细胞凋亡指数(AI),生长抑制率(IR),SurvivinmRNA和蛋白表达的变化。结果转染后反义链组均能够下调SurvivinmRNA含量和蛋白表达,凋亡细胞增多。转染后24h100、200和400nmol/L反义链组AI为14.8%、19.4%及53.8%;IR(%)为45.98±2.99、50.96±3.38、72.79±2.48,反义链组高于其他对照组。结论Survivin反义寡核苷酸能够抑制胃癌细胞增殖。     

生长抑素抑制人结肠癌细胞增殖的实验研究

目的：研究外源性生长激素（GH）和生长抑素（SS）对人结肠癌细胞株HT-29的影响，并探讨其作用机制。方法：人结肠癌细胞株HT-29分成正常对照组、生长抑素组（SS组）、生长激素组（GH组）和生长抑素＋生长激素组（GH＋SS组）。MTT法测定细胞抑制率，流式细胞仪测定细胞周期分布、增殖指数、凋亡率，RT—PCR方法测定bcl．2及baxmRNA水平。结果：生长抑素能够明显抑制人结肠癌细胞株HT-29增殖（P〈0．01）、降低S期和G2／M期细胞比例（P〈0．05）、降低增殖指数（PI）（P〈0．05）、促进细胞凋亡（P〈0．01）、降低bcl-2mRNA表达（P〈0．05）、提高baxmRNA表达（P〈0．01），生长激素则无明显作用。GH＋SS组表现与SS组相似。结论：生长抑素可能通过抑制GdG．期细胞进入S期和G2／M期以及促进细胞凋亡两种途径抑制体外培养的人结肠癌细胞株HT-29增殖。生长抑素可能是通过改变bax基因和bcl-2基因的表达影响肿瘤细胞的凋亡。生长激素对体外培养的人结肠癌细胞株HT-29无显著影响。     

Survivin反义核酸诱导乳腺癌细胞凋亡的实验研究

目的探讨Survivin反义核酸技术诱导乳腺癌细胞凋亡的作用及效果。方法本实验共分6组，分为以脂质体介导反义寡核苷酸组（ASODN／Lip）、无义寡核苷酸组（NODN／Lip）及RPMI 1640培养液的空白对照组（Lip），转染人乳腺癌MCF-7细胞系，应用Hoechst 33258／PI双重染色观察MCF-7细胞的形态学改变，透射电镜观察细胞超微结构，流式细胞仪检测细胞周期和细胞凋亡的变化，DNA凝胶电泳观察凋亡情况，研究Survivin反义寡核苷酸对MCF-7乳腺癌细胞的生长抑制作用。结果Hoechst 33258／PI染色及透射电镜观察可见转染后的细胞结构呈凋亡样改变；流式细胞仪检测见转染后细胞凋亡显著增加，并出现G2／M期阻滞现象；DNA凝胶电泳在600ng／ml，800ng／ml ASODN／Lip组的电泳图谱上呈现出明显的“梯状”现象。结论凋亡抑制基因Survivin表达下涧对乳腺癌细胞的生长抑制作用主要是通过诱导细胞发生凋亡以及阻止有丝分裂发生在G2／M阻滞期来实现，Survivin靶向反义核酸技术可能成为乳腺癌基因治疗的一种有效方法。     

反义寡核苷酸抑制Survivin基因表达对PC-3的体外作用

目的　观察Survivin反义寡核苷酸 (ASODN)PC 3细胞表达Survivin蛋白、细胞凋亡、增殖的影响。方法　设计并合成特异性靶向Survivin的ASODN。PC 3分为 6组 :空白对照组、脂质体转染对照组、正义链转染对照组、2 0 0、40 0和 60 0nmol/LASODN转染组。作用 2 4h后收获各组细胞。观察细胞形态变化及超微结构变化 ,免疫组织化学法和流式细胞术法检测各组细胞Sur vivin表达情况 ,流式细胞术检测各组细胞增殖指数 (AI)和凋亡指数 (PI) ,四甲基偶氮唑蓝 (MTT)法检测ASODN对细胞的生长抑制率。结果　电镜下可见到典型凋亡样改变 ;各ASODN转染组细胞Survivin表达有不同程度减弱 ;2 0 0、40 0和 60 0nmol/LASODN转染组AI和PI分别为 (8.5 0±0 .79) % ,(13 .78± 0 .5 6) % ,(2 1.3 1± 1.67) %和 (3 7.80± 1.72 ) % ,(2 5 .10± 2 .18) % ,(19.90±0 .97) % ,分别与对照组相比差异有显著性 (P <0 .0 5 ) ,而AI和PI在各对照组间差异无显著性(P >0 .0 5 )。转染后第 3天 2 0 0、40 0和 60 0nmol/LASODN组相对于空白对照组的抑制率分别为60 .0 %、66.0 %、78.6%。结论　SurvivinASODN转染后能下调Survivin蛋白表达 ,诱导PC 3细胞凋亡 ,抑制PC 3细胞增殖。     

针对K-ras基因点突变的反义寡核苷酸对人胰腺癌Patu 8988细胞的抑制作用

目的 检测人胰腺癌Patu8988细胞K-ras基因点突变形式，并观察针对该点突变的硫代反义寡核苷酸在体内外对Patu8988细胞增殖和凋亡的影响。方法顺序特异引物聚合酶链反应（PCR-SSP）法和基因测序检测Patu8988细胞K-ras点突变形式，根据点突变形式设计并合成硫代反义寡核苷酸（K-ras mutation ASODN）作用Patu 8988，通过噻唑蓝（MTT）比色法检测细胞生长情况；流式细胞术（FCM）检测K-ras蛋白表达和细胞凋亡；逆转录-聚合酶链反应（RT—PCR）检测K-ras mRNA表达水平；以Patu8988细胞建立裸鼠胰腺癌模型观察K-ras mutation ASODN在体内的抗肿瘤效果。结果 PCR-SSP法和基因测序检测表明Patu 8988细胞存在K-ras基因第12密码子点突变，其突变方式为GGT→GTT.体外实验表明K-rasmutation ASODN组较正义寡核苷酸（SODN）组、随机寡核苷酸（RODN）组和空白对照组可明显抑制Patu8988细胞生长（P〈0．01），并呈时间．剂量效应关系；转染48h后，K—ras mutation ASODN组的K-ras蛋白和mRNA表达程度较SODN组、RODN组和对照组均明显降低（P〈0．01），而细胞凋亡明显增多（P〈0．05）。体内实验表明K-ras mutation ASODN较SODN组、RODN组和对照组能有效抑制BALB／C裸鼠人胰腺癌的生长（P〈0．01）。结论 针对K-ras基因第12密码子点突变的反义寡核苷酸可明显抑制人胰腺癌Patu 8988细胞生长，促进细胞凋亡，其机制可能是通过下调K-ras蛋白和K—ras mRNA表达而起作用。     

泛素特异性肽酶22经Wnt/β-catenin通路调控结直肠癌化疗耐药的机制研究

目的探讨泛素特异性肽酶22（USP22）作用于Wnt/β-catenin信号通路参与结直肠癌的发生和化疗耐药的分子机制。 方法采用氟尿嘧啶（5-Fu）处理结直肠癌细胞株HT-29,建立耐药细胞株HT-29/5-Fu;构建USP22 siRNA稳定表达细胞株（表示为HT-29-sh USP22、HT-29/5-Fu-sh USP22）。CCK-8法检测HT-29/5-Fu细胞对5-Fu的敏感性、抑制USP22表达后结直肠癌细胞对5-Fu敏感性的影响;采用Western blotting检测不同质量浓度5-Fu诱导下HT-29细胞中USP22蛋白表达,HT-29和HT-29/5-Fu细胞中USP22和β-catenin蛋白表达,以及抑制USP22表达对结直肠癌细胞USP22、β-catenin表达的影响。 结果（1）HT-29与HT-29/5-Fu细胞对5-Fu的IC₅₀值分别为（1.58±0.23）mg/L和（14.58±0.94）mg/L,其中HT-29/5-Fu细胞对5-Fu的敏感性显著下降（n=6,t=8.476,P<0.01）。（2）在0.5、5.0 mg/L的5-Fu诱导后,HT-29细胞内USP22蛋白表达水平（USP22/β-actin）显著升高（0.5 mg/L vs 0 mg/L：t=7.618,P<0.05;5.0 mg/L vs 0 mg/L：t=6.992,P<0.05）。HT-29/5-Fu组中USP22蛋白表达水平为0.92±0.11,显著高于HT-29组的0.18±0.06（t=7.618,P<0.05）。（3）HT-29-sh USP22组对5-Fu的IC₅₀为（0.25±0.23）mg/L,显著低于HT-29组（t=6.662,P<0.01）。HT-29/5-Fu-sh USP22组对5-Fu的IC₅₀为（1.36±0.14）mg/L,显著低于HT-29/5-Fu组（t=7.002,P<0.01）,但与HT-29组相比,差异无统计学意义（t=1.586,P>0.05）,抑制USP22表达可增强结直肠癌细胞HT-29对5-Fu的敏感性。（4）HT-29-sh USP22组的USP22蛋白表达水平为0.07±0.01,与HT-29组相比下调（t=7.105,P<0.01）。HT-29/5-Fu-sh USP22组的USP22蛋白表达水平为0.33±0.02,与HT-29/5-Fu组相比,USP22蛋白表达水平下调（t=6.153,P<0.01）。HT-29-sh USP22、HT-29/5-Fu-sh USP22中β-catenin蛋白表达水平与相应对照组HT-29、HT-29/5-Fu相比显著下调（HT-29-sh USP22 vs HT-29：t=8.823,P<0.01;HT-29/5-Fu-sh USP22 vs HT-29/5-Fu：t=7.656,P<0.01）。 结论5-Fu可诱导结直肠癌细胞USP22表达增高。抑制USP22表达可增加结直肠癌细胞对5-Fu的药物敏感性,其机制可能是抑制Wnt/β-catenin信号通路,从而有效逆转结直肠癌细胞对5-Fu的耐药。     

β1整合素反义寡核苷酸对人胰腺癌BXPC-3细胞体外侵袭力的影响

目的观察β1整合素反义寡核苷酸（ASODN）对人胰腺癌BXPC-3细胞体外侵袭力的影响。方法采用脂质体将不同浓度β1整合素ASODN转染到人胰腺癌BXPC-3细胞中，逆转录-聚合酶链反应（RT—PCR）、Western印迹法和Transwell侵袭室方法分别检测细胞β1整合素mRNA、蛋白表达水平及体外侵袭能力。结果与对照组相比，32～128mg／LASODN转染后可抑制β1整合素mRNA和蛋白的表达（P〈0．05），64mg／LASODN转染使BXPC-3细胞体外侵袭力明显下降（P〈0．05）。结论靶向β1整合素的ASODN可有效抑制其在人胰腺癌BXPC-3细胞中的表达。并降低癌细胞体外侵袭力。     

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.     

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.     

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.