表皮生长因子对PC-3细胞内皮素-1及其受体mRNA表达的影响

目的:探讨表皮生长因子(EGF)对激素非依赖性前列腺癌(HRPC)PC-3细胞中内皮素1(ET-1)及其受体mRNA表达的影响。方法:EGF作用不同时间(0、8、16、24、32、48h)后,RT-PCR法测定PC-3细胞中ET-1及其受体ETAR mRNA、ETBR mRNA表达;EGF干预24h后,RT-PCR法测定ET-1及其受体ETAR mRNA、ETBR mRNA表达变化。结果:在PC-3细胞中可检测到ET-1及ETAR mRNA表达,但无ETBR mRNA表达;EGF可上调ET-1及ETAR mRNA表达,与对照组比较,差异具有显著性;ET-1及ETAR mRNA表达随EGF干预时间增加而增加,EGF作用不同时间对PC-3细胞ET-1、ETAR mRNA表达的影响不同,差异具有显著性(P<0.05)。结论:EGF可上调PC-3细胞中ET-1及ETAR mRNA表达,为HRPC的治疗提供了分子生物学基础。     

高糖对人腹膜间皮细胞局部内皮素系统表达的影响

目的:研究高浓度葡萄糖对人腹膜间皮细胞(HPMC)局部内皮素系统表达的影响,并应用非特异性内皮素受体拮抗剂即ETA/ETBR拮抗剂PD142893进行干预,探讨高浓度葡萄糖透析液导致腹膜受损的机制.方法:以人腹膜间皮细胞株(HMrSV5)为研究对象,采用放免法检测不同时间(12 h、24 h和48 h)、不同浓度(50、100、150、200、250 mmol/L)的葡萄糖、甘露醇作用下HPMC分泌的ET-1水平.采用半定量逆转录多聚酶链反应(RT-PCR)检测局部内皮素系统ET-1、ETAR、ETBR及ECE的基因表达.采用ELISA检测不同浓度ET-1、葡萄糖作用下IL-1β水平,并在此基础上加入PD142893,观察IL-1β的变化.结果:(1)正常HPMC分泌低水平的ET-1,高浓度的葡萄糖可诱导HPMC分泌 ET-1增加,呈时间和剂量依赖.高浓度的甘露醇作用下,HPMC分泌的ET-1与正常对照组相比未见明显差异.(2)正常HPMC表达完整的ET-1、ETAR、ETBR、ECE mRNA.高糖作用下ET-1、ETAR、ETBR mRNA表达增强,而高糖对ECE mRNA的表达无明显影响.(3)ET-1、高糖刺激HPMC分泌IL-1β,呈剂量依赖.PD142893可明显减少高糖诱导的IL-1β的分泌.结论:正常HPMC存在局部内皮素系统,高浓度葡萄糖诱导其表达增加,高浓度葡萄糖透析液导致腹膜受损可能部分通过内皮素途径,内皮素可能是导致CAPD患者腹膜纤维化的重要因素.     

内皮素受体拮抗剂对前列腺癌细胞PC3和成骨细胞相互作用的影响

目的 在细胞共培养微环境下,观察内皮素(ET)受体拮抗剂阻断内皮素轴对前列腺癌细胞PC3和成骨细胞SaOS_2相互作用的影响.方法 利用细胞体外共培养系统,比较前列腺癌细胞PC3和成骨细胞SaOS_2在共培养微环境下和单独培养环境下细胞增殖的差异.共培养微环境下,分别以ET_A受体(ET_AR)拮抗剂BQ123和ET_B受体(ET_BR)拮抗剂BQ788阻断相应的ET受体,观察其对前列腺癌细胞和成骨细胞增殖的影响.同时,通过酶联免疫吸附试验(ELISA)法测定各组培养液中的ET-I浓度,通过逆转录.聚合酶链反应(RT-PCR)测定PC3细胞、SaOS_2:细胞ET-I及其受体的mRNA表达,比较它们的表达差异.结果 与单独培养比较,共培养微环境下的PC3细胞和SaOS_2细胞的增殖数量均显著升高(P均＜0.05).ET_AR拮抗剂BQ123能阻断共培养微环境对SeOS:细胞的生长促进作用,部分阻断共培养微环境对PC3细胞的生长促进作用,而ETBR拮抗剂BQ788则无显著的干预作用.EUSA结果显示共培养组培养液中ET-1浓度[(14.26±1.06)βg/L/10~5个细胞]显著高于单独培养组[(6.58±0.74)pc/L/105个细胞,P＜0.05].RT-PCR结果显示PC3细胞表达ET-1和ET_AR,SaOS_2细胞只表达ET_AR;与单独培养比较,共培养微环境下PC3细胞ET-l的表达显著升高(P＜0.05),而PC3细胞和SaOS2细胞ET_AR的表达差异均无统计学意义(P＞0.05).结论 ET-1及ET_AR构成的内皮素轴是共培养微环境中前列腺癌细胞PC3和成骨细胞之间相互作用促进增殖的重要链接因子,而ETAR拮抗剂能有效地抑制两者间的相互作用,抑制PC3细胞增殖.     

内皮素-1及其受体在良性前列腺增生中的表达研究

目的探讨内皮素-1及其受体(ETAR与ETBR)在良性前列腺增生(BPH)移行区组织中表达的意义。方法采用免疫组化及Western blot技术检测5例正常前列腺组织(NP)与16例BPH组织中内皮素-1及其受体表达情况。结果BPH移行区组织中内皮素-1阳性面积为(77936.16±85291.33)μm2,ETAR积分吸光度为316.6±65.2,明显高于正常前列腺组织(阳性面积75.68±110.85μm2,ETAR积分吸光度为140.2±64.8),而2组ETBR的表达(积分吸光度分别为81.4±31.8,105.0±45.5)差异无统计学意义。结论BPH移行区组织中内皮素-1及其ETAR表达上调,在BPH的病理生理过程中可能产生重要作用。     

姜黄素对雄激素非依赖性前列腺癌细胞PC-3及血管内皮生长因子的影响

目的：研究姜黄素对雄激素非依赖性前列腺癌细胞株PC-3细胞体外作用及其对血管内皮生长因子（VEGF）表达的影响，探讨其抗肿瘤的作用机制。方法：分别用0、6．25、12．5、25、50μmol／L浓度的姜黄素作用于PC-3细胞，12、24、36、48、72、96h后台盼蓝拒染法、四甲基偶氮唑蓝（MTT）法检测细胞生长活性；24h后流式细胞仪测定细胞周期及凋亡的变化，透射电镜观察细胞超微结构变化；半定量RT-PCR法检测PC-3细胞内VEGF mRNA的表达；ELISA检测细胞上清液中VEGF浓度。结果：姜黄素能显著抑制PC-3细胞的增殖，呈剂量与时间依赖性，不同浓度姜黄素组之间及不同时间组之间差异均有统计学意义（P〈0．01）。不同浓度姜黄素诱导PC-3细胞出现剂量依赖性G2／M期阻滞（P〈0．01），且各浓度组凋亡细胞比例均显著高于空白对照组（P〈0．01），差异有统计学意义；姜黄素作用24h后PC-3细胞出现凋亡的形态学改变；PC-3细胞内VEGF mRNA的表达和细胞上清液中VEGF呈剂量依赖性降低。结论：姜黄素能显著抑制体外PC-3细胞的生长，并促进其G2／M期阻滞和凋亡，VEGF mRNA及蛋白的表达也明显降低，可能是其抑制肿瘤和血管生长的机制之一。     

内皮素1及其受体拮抗剂对HSC-T6细胞内皮素受体mRNA表达的影响

目的探讨内皮素1(ET-1)及其受体拮抗剂对HSC-T6细胞内皮素受体mRNA表达的作用及其机制,进一步了解缩血管物质在门静脉高压症发病机制中的作用。方法培养的肝星状细胞HSC-T6细胞系分为7组,分别为空白对照组,ET-1组(培养瓶中加入10 nmol/L的ET-1),BQ-123组[加入1μmol/L的选择性内皮素A型受体(ETRA)拮抗剂BQ-123],BQ-788组[加入1μmol/L的选择性内皮素B型受体(ETRB)拮抗剂BQ-788],ET-1+BQ-123组(加入10 nmol/L的ET-1和1μmol/L的BQ-123),ET-1+BQ-788组(加入10 nmol/L的ET-1和1μmol/L的BQ-788),ET-1+BQ-123+BQ-788组(加入10 nmol/L的ET-1、1μmol/L的BQ-123和1μmol/L的BQ-788)。采用逆转录聚合酶链反应(RT-PCR)检测HSC-T6细胞内皮素受体mRNA的表达。结果ET-1+BQ123+BQ788组ETRA mRNA的表达与空白对照组相比差异具有统计学意义(分别为0.292±0.023和0.440±0.030,P<0.05),其余各组与之相比无明显差异(P>0.05);与ET-1组相比,ET-1+BQ788组和ET-1+BQ123+BQ788组ETRA mRNA表达低,差异具有统计学意义(分别为0.329±0.044,0.292±0.023和0.487±0.039,P<0.05];与空白对照组相比,ET-1组ETRB mRNA表达上调,但差异无统计学意义(分别为0.499±0.136和0.289±0.047,P=0.134];与ET-1组相比,ET-1+BQ788组ETRB mRNA表达明显低,差异具有统计学意义(分别为0.153±0.071和0.499±0.136,P<0.05)。结论ET-1对ETRA mRNA的表达无明显作用;ET-1本身可能会上调HSC-T6 ETRB mRNA的表达,ET-1作用于ETRA时则会抑制ETRB mRNA的表达。     

成纤维细胞生长因子受体1在胰腺癌细胞中的表达和调控

目的 研究成纤维细胞生长因子受体1(FGFR1)蛋白和mRNA在胰腺癌细胞系中的表达和调控机制.方法 采用Western免疫印迹实验、Northern印迹分析和RT-PCR检测FGFR1在胰腺癌细胞中的表达.使用外源性生长因子刺激细胞并使用激酶抑制剂阻断细胞内信号转导通路,观察FGFR1蛋白和mRNA在胰腺癌细胞中表达的变化情况.结果 FGFR1蛋白和mRNA在胰腺癌细胞系中均有不同程度的表达.生长因子刺激可上调FGFR1蛋白和mRNA的表达水平.其中IGF-1、EGF和FGF2显著增加Mia PaCa-2细胞FGFR1的表达,EGF和FGF2显著增加PANC-1细胞FGFR1的表达(P＜0.05).FGF2对FGFR1表达的调节具有时间依赖性.ERK1/2抑制剂UO126和p38 MAPK抑制剂SB203580降低了PANC-1细胞中FGFR1的蛋白和mRNA的表达水平. 结论生长因子可上调FGFR1在胰腺癌细胞中的表达水平,MAPK信号转导通路中的ERK1/2和p38 MAPK亚通路参与FGFR1表达的调节.     

胆汁性肝硬化猪肝组织中内皮素受体及诱导型一氧化氮合酶mRNA表达的意义

目的　研究胆汁性肝硬化猪肝组织中内皮素受体 (ETAR、ETBR)及诱导型一氧化氮合酶 (iNOS)mRNA的表达及其对肝脏血液循环的影响。方法　湖北白种猪 15头 ,其中实验组 10头 ,对照组 5头。监测门静脉压 (Pp)、门静脉血流量 (Qp)和平均动脉压 (MAP)的变化 ,用原位杂交方法检测肝组织中ETAR、ETBR及iNOSmRNA的表达水平。结果　术后 4周实验组Pp(14 .6±1.7)mmHg (1mmHg =0 .13 3kPa)、Qp(3 2 .3± 2 .8)ml·min-1·kg-1及MAP(80 .5± 2 .5 )mmHg显著高于对照组的 (8.1± 3 .6)mmHg、(14 .2± 3 .7)ml·min-1·kg-1和 (10 8.3± 6.5 )mmHg(P <0 .0 1)。实验组ETAR、ETBR及iNOSmRNA的表达水平分别为 0 .78± 0 .2 0、0 .90± 0 .2 3和 0 .75± 0 .13 ,均显著高于对照组 (分别为 0 .3 8± 0 .2 6、0 .2 4± 0 .15和 0 .3 2± 0 .11,P <0 .0 1)。结论　胆汁性肝硬化猪肝组织中ETAR、ETBR及iNOSmRNA表达水平的变化影响肝脏血液循环的调节。     

过氧化物酶体增殖因子活化受体γ在胰腺癌中的表达及其意义

目的：研究过氧化物酶体增殖因子活化受体（PPAR）在胰腺癌中的表达，探讨其可能意义。方法：分别应用免疫组织（细胞）化学和逆转录-聚合酶链式反应（RT-PCR）检测正常胰腺组织、24例胰腺癌组织和胰腺癌细胞株PC-3及PANC-1中PPARα、δ、γ表达。结果：RT-PCR显示正常胰腺组织PPAR各亚型mRNA均无表达，而胰腺癌组织和胰腺癌细胞株PPARγmRNA高表达，PPARα和PPARδmRNA则无表达。免疫组织（细胞）化学显示胰腺癌组织及细胞株PPAR（呈高表达，在胰腺癌组织表达总阳性率为79.17％。结论：本文初步观察到核内受体PPARγ在人胰腺癌组织及人胰腺癌细胞株中表达上调。PPARα为今后胰腺癌化学预防一个新的靶点。     

机械压力对人脐静脉内皮细胞ET-1、NO合成的影响和意义

目的探讨压力增高对血管内皮细胞分泌血管活性物质功能的影响及其在门静脉高压症发病机制中的作用。方法用RT-PCR方法半定量研究人脐静脉内皮细胞ET-1、eNOS、i-NOS mRNA的表达;用硝酸还原酶法检测各组细胞培养液中NO代谢产物NO2-/NO3-的含量,免疫荧光标记激光扫描共聚焦显微镜检测培养细胞的ET-1蛋白表达。结果ET-1和eNOS mR-NA在正常培养的内皮细胞中即有表达,iNOS mRNA则几乎无表达。生理水平压力刺激下各组各待测基因mRNA表达与对照组无显著性差异。超生理范围压力刺激后,ET-1 mRNA有显著性升高。eNOS mRNA在40 mm Hg 24 h后才有显著性差异。iNOS mRNA在不同条件下均无显著变化。在细胞培养液中分别加入细胞外钙螯合剂EGTA、PKC抑制剂后,则见ET-1、eNOS mRNA表达下降。结论压力增高可刺激血管内皮细胞合成ET-1、NO,其作用在转录水平,其作用机制分别与PKC信号通路和细胞外钙浓度有关。门静脉压力增高与血管内皮细胞合成ET-1、NO增多之间存在相互作用。     

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.     

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.     

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.