丙泊酚对布比卡因诱导的PC12细胞毒性、活性氧和过氧化氢酶的影响

目的探讨丙泊酚对布比卡因诱导的PC12细胞毒性的保护作用及活性氧（ROS）和过氧化氢酶（CAT）在其中的作用。方法培养的PC12细胞分成四组：正常对照组（C组）；丙泊酚组（P组），在细胞培养基中加入2mmol／L，丙泊酚；布比卡因组（B组），在细胞培养基中加入0．09mmol／L布比卡因；丙泊酚加布比卡因组（PB组），在细胞培养基中同时加入2mmol／L，丙泊酚和0．09mmol／L布比卡因；每组6孔。培养6h和24h后，用倒置相差显微镜观察细胞形态、MTT比色微量分析细胞活性，测定上清液乳酸脱氢酶（LDH）活性和细胞内CAT、ROS活性。结果与c组相比，B组PC12细胞活性和细胞内CAT活性显著降低（P＜0．01），LDH活性和细胞内ROS活性显著增加（P＜0．01）；P组PC12细胞活性及其它指标无显著变化；与B组相比，PB组PC12细胞活性和细胞内CAT活性显著增加（P〈0．05），LDH活性和细胞内ROS活性显著降低（P＜0．01）。结论布比卡因对PC12细胞具有毒性作用，可能与降低细胞内CAT活性、增加ROS活性有关；丙泊酚通过保护细胞内CAT活性和清除ROS而减轻布比卡因诱导的PC12细胞毒性。     

丙泊酚对布比卡因诱导的PC12细胞毒性、活性氧和过氧化氢酶的影响

目的探讨丙泊酚对布比卡因诱导的PC12细胞毒性的保护作用及活性氧(ROS)和过氧化氢酶(CAT)在其中的作用。方法培养的PC12细胞分成四组:正常对照组(C组);丙泊酚组(P组),在细胞培养基中加入2mmol/L丙泊酚;布比卡因组(B组),在细胞培养基中加入0.09mmol/L布比卡因;丙泊酚加布比卡因组(PB组),在细胞培养基中同时加入2mmol/L丙泊酚和0.09mmol/L布比卡因;每组6孔。培养6h和24h后,用倒置相差显微镜观察细胞形态、MTT比色微量分析细胞活性,测定上清液乳酸脱氢酶(LDH)活性和细胞内CAT、ROS活性。结果与C组相比,B组PC12细胞活性和细胞内CAT活性显著降低(P<0.01),LDH活性和细胞内ROS活性显著增加(P<0.01);P组PC12细胞活性及其它指标无显著变化;与B组相比,PB组PC12细胞活性和细胞内CAT活性显著增加(P<0.05),LDH活性和细胞内ROS活性显著降低(P<0.01)。结论布比卡因对PC12细胞具有毒性作用,可能与降低细胞内CAT活性、增加ROS活性有关;丙泊酚通过保护细胞内CAT活性和清除ROS而减轻布比卡因诱导的PC12细胞毒性。     

依达拉奉对氯胺酮致PC12细胞凋亡时线粒体功能的影响

目的评价依达拉奉对氯胺酮致PC12细胞损伤时线粒体功能的影响。方法将神经生长因子诱导分化的PC12细胞采用随机数字表法分为3组(n=30):对照组PC12细胞正常培养;氯胺酮组PC12细胞诱导分化后第7天加入PBS+100 μmol/L氯胺酮培养;依达拉奉+氯胺酮组加入10 μmol/L依达拉奉+100 μmol/L氯胺酮培养。于培养24 h时采用试剂盒测定细胞活力、caspase-3/7活性、ROS活性、ATP含量和NADH/NAD+比例, TUNEL法观察细胞凋亡情况, 计算细胞凋亡率。结果与对照组比较, 氯胺酮组和依达拉奉+氯胺酮组细胞活力、caspase-3/7活性、NADH/NAD+比例和细胞凋亡率升高, ROS活性和ATP含量降低(P<0.05);与氯胺酮组比较, 依达拉奉+氯胺酮组细胞活力、caspase-3/7活性、NADH/NAD+比例和细胞凋亡率降低, ROS活性和ATP含量升高(P<0.05)。结论依达拉奉抑制氯胺酮致PC12细胞凋亡的机制与其改善线粒体功能有关。     

咪达唑仑对N-甲基-D-天冬氨酸所致PC12细胞损伤的保护作用

目的 观察静脉麻醉药咪达唑仑对N-甲基-D-天冬氨酸(NMDA)致PC12细胞损伤的保护作用,并探讨其可能的作用机理。方法 乳酸脱氢酶(LDH)法及MTT比色法判断细胞损伤程度及细胞存活率,Fura-2/AM荧光标记法测定细胞内Ca2+浓度([Ca2+]i),分光光度法测定细胞一氧化氮合酶(NOS)活性。结果 NMDA 300μmol·L-1处理4 h可明显导致PC12细胞的损伤,LDH释放量明显增加,存活细胞吸光度值OD570nm明显降低(P<0.01),[Ca2+]和NOS活性则明显增加(P<0.01)。咪达唑仑0.33～30μmol·L-1与NMDA 300μmol·L-1共同作用4 h后,除0.33 gmol·L-1组外,其他各剂量组均有较好的细胞保护作用,LDH明显降低而OD570nm显著增加(P<0.01)。咪达唑仑3和30 μmol·L-1均可显著降低NMDA诱导的[Ca2+].水平及NOS活性(P<0.01)。结论 咪达唑仑对NMDA所致PC12细胞损伤有明显的保护作用.可能与其抑制钙超载及NOS活性有关。     

一氧化氮合酶反义RNA重组腺相关病毒载体体外提高PC12细胞耐缺氧的能力

目的探讨2种分别携带神经元型一氧化氮合酶（nNOS）、诱导型一氧化氮合酶（iNOS）反义RNA重组腺相关病毒载体（rAAV-AsnNOS和rAAV-AsiNOS）提高PC12细胞耐氧能力和抑制PC12细胞凋亡的作用机制。方法将PC12细胞培养基换成分别含有rAAV—AsnNOS、rAAV-Asi—NOS和rAAV-LacZ（携带β-半乳糖苷酶的结构基因重组腺相关病毒载体）的10％胎牛血清DMEM，设立对照组，测定不同rAAV转染后PCI2细胞在不同缺氧时间下细胞生长趋势和乳酸脱氢酶（LDH）活性改变，流式细胞仪（FCM）测定细胞凋亡率，FCM和半定量RT—PCR分别分析nNOS、iNOS、p38MAPK和Caspase-3阳性细胞百分比和mRNA的表达。结果一定感染复数的rAAV对PC12细胞生长趋势无明显影响；转染rAAV-AsnNOS的PC12细胞在缺氧1—6h时LDH活性、细胞凋亡率以及nNOS、p38MAPK和Caspase-3阳性细胞百分比和mRNA表达量均较对照组、rAAV-LacZ组和rAAV-AsiNOS组均降低；转染rAAV—AsiNOS的PC12细胞在缺氧6～24h时LDH活性、细胞凋亡率以及iNOS、p38MAPK和Caspase-3阳性细胞百分比和mRNA表达量也均较对照组、rAAV—LacZ组和rAAV-AsnNOS组降低。结论在体外神经细胞缺氧模型中，转染后PC12细胞能够耐受缺氧损伤；转染rAAV-AsnNOS病毒载体的PC12细胞能够在缺氧早期抑制nNOS、p38MAPK和Caspase-3的表达，转染rAAV-AsiNOS病毒载体的PC12细胞能够在缺氧晚期抑制iNOS、p38MAPK和Caspase-3的表达。     

大麻素受体2在谷氨酸诱发小胶质细胞损伤中的作用

目的 评价大麻素受体2(CB2受体)在谷氨酸诱发小胶质细胞损伤中的作用.方法 采用随机数字表法,将小胶质细胞随机分为4组:对照组(C组)细胞常规培养26h;小胶质细胞损伤组(Ⅰ组)细胞于含10 mmol/L谷氨酸的培养基中孵育24h;CB2受体特异性激动剂AM1241组细胞于含2 μmol/L AM1241的培养基中孵育2h,然后于含10 mmol/L谷氨酸的培养基中孵育24 h;CB2受体特异性拮抗剂AM630组细胞含2 μmol/L AM630的培养基中孵育2h,然后于含10 mmol/L谷氨酸的培养基孵育24h.测定细胞活力和LDH释放量,观察细胞形态学.结果 与C组比较,Ⅰ组、AM1241组和AM630组细胞活力降低,LDH释放量增加(P＜0.05);与Ⅰ组比较,AM1241组细胞活力升高,LDH释放量减少(P＜0.05),AM630组细胞活力和LDH释放量差异无统计学意义(P＞0.05).结论 谷氨酸通过抑制CB2受体的功能诱发小胶质细胞损伤.     

高温预处理对PC12细胞高温损伤的影响

目的探讨高温预处理（HPC）对大鼠嗜铬细胞瘤株（PC12）细胞高温损伤的影响及其机制。方法体外培养PC12细胞,随机分为4组（n=6）,正常对照组（C组）37℃培养箱中常规培养23 h；高温预处理组（HPC组）将细胞置于42℃培养箱中1h后,37℃常规培养22h；严重高温损伤组（LH组）细胞常规培养19h,将细胞置于46℃培养箱中2h后,恢复常规培养2h；高温预处理＋严重高温损伤组（HPC＋LH组）细胞置于42℃培养箱1h,恢复常规培养18h,再置于46℃培养箱2h后,恢复常规培养2h。各组处理后观察细胞形态学,测定细胞活力、上清液乳酸脱氢酶（LDH）活性,检测细胞内HSP70的表达。结果与C组比较,LH组、HPC＋LH组细胞活力降低,LDH活性升高,LH组细胞内HSP70表达下调,HPC组细胞内HSP70表达上调（P＜0．01）；与LH组比较,HPC＋LH组细胞活力升高,LDH活性降低,细胞内HSP70表达上调（P＜0．01）。结论高温预处理可通过诱导HSP70表达上调,减轻高温对PC12细胞的损伤。     

IGFBP 3在白藜芦醇抑制胃癌细胞增殖过程中的作用

目的研究在白藜芦醇（Res）抑制胃癌细胞增殖过程中,胰岛素样生长因子结合蛋白 3（IGFBP 3）表达的变化。方法噻唑蓝（MTT）法测定Res对BGC 823细胞增殖的抑制程度,实时荧光定量聚合酶链反应（qRT PCR）和Western blot技术检测Res处理后BGC 823细胞中IGFBP 3表达变化,siRNA技术沉默IGFBP 3基因表达,MTT法观察Res对BGC 823细胞增殖的影响,流式细胞技术测定各组细胞凋亡率。结果Res能够抑制BGC 823生长,经20,40,80,160 μmol·L－1Res处理后,细胞存活率分别为（82.35±10.65）%,（74.30±12.36）%,（62.80±14.66）%,（50.75±11.14）%。Res刺激后,IGFBP 3表达水平升高,与对照组比较,IGFBP 3 mRNA水平增高2.96 倍（P＜0.05）, IGFBP 3蛋白水平变化与其mRNA一致。siRNA技术沉默IGFBP 3表达后,160 μmol·L－1Res刺激BGC 823细胞,细胞存活率下降（78.5±9.86）%,但高于同浓度下Res刺激的未经IGFBP 3沉默的BGC 823细胞（P＜0.05）。IGFBP 3沉默后,160 μmol·L－1Res处理后BGC 823细胞凋亡率（20.13±9.12）%,明显低于未经IGFBP 3沉默的BGC 823细胞［（35.48±11.12）%］,且差异有统计学意义（P＜0.05）。结论Res可以抑制BGC 823细胞增殖,促进其凋亡。该机制涉及IGFBP 3高表达。     

异丙酚对布比卡因诱导的PC12细胞毒性的作用

目的 探讨异丙酚对布比卡因诱导的PC12细胞毒性的作用及其可能机制。方法PCI2细胞接种于96孔培养板中培养，随机分为4组：对照组、布比卡因组、异丙酚组和布比卡因＋异丙酚组，分别加入Hanks液、布比卡因（终浓度为0．03、0．06、0．09、0．12、0．15mmol／L）、异丙酚（终浓度为1、2,4、8mmol／L）以及同时加入布比卡因（终浓度为0．09mmol／L）和异丙酚（终浓度为1、2,4、8mmol／L）。培养24h时，采用二甲基噻唑二甲基四唑溴盐比色微量分析法测定各孔的细胞活力和上清液乳酸脱氢酶（LDH）的活性，应用流式细胞仪检测硫氧还蛋白-1（Trx-1）和硫氧还蛋白还原酶-1（TrxR-1）表达率。结果 与对照组比较，布比卡因组PC12细胞活力降低（P〈0．01），且呈浓度依赖性；异丙酚组PC12细胞活力差异无统计学意义（P〉0．05）。与布比卡因组的0．09mmol／L亚组比较，布比卡因＋异丙酚组的2—8mmol／L亚组PC12细胞活力增加（P〈0．05）。与对照组比较，布比卡因组和布比卡因＋异丙酚组LDH活性升高，Trx-1和TrxR-1表达率降低（P〈0．01）；与布比卡因组比较，异丙酚组和布比卡因＋异丙酚组LDH活性降低，Trx-1和TrxR-1表达率升高（P〈0．01）。结论 布比卡因对PC12细胞具有浓度依赖性的细胞毒性作用。异丙酚可通过保护内源性硫氧还蛋白系统减轻布比卡因诱导的PCI2细胞的毒性。     

槲皮素和黄芪甲苷对大鼠缺氧心肌细胞的保护作用

目的 了解并比较槲皮素、黄芪甲苷对体外培养的缺氧心肌细胞的保护作用，寻找其作用的量效关系。方法 将SD乳鼠心肌细胞分成单纯缺氧组（A组）、缺氧＋100mg／L槲皮素组（B组）、缺氧＋50mg／L槲皮素组（c组）、缺氧＋25mg／L槲皮素组（D组）、缺氧＋50．0mg／L黄芪甲苷组（E组）、缺氧＋25．0131mg／L黄芪甲苷组（F组）、缺氧＋12．5mg／L黄芪甲苷组（G组）、缺氧＋10mg／L维生素E组（H组）。各组细胞原代培养后先加入相应浓度的槲皮素、黄芪甲苷、维生素E，再行缺氧处理12h（A组培养后直接行缺氧处理）。检测各组心肌细胞活力和乳酸脱氢酶（LDH）、丙二醛（MDA）、超氧化物歧化酶（SOD）、活性氧（ROS，只检测A、C、F、H组）值。结果B～G组与A组比较，LDH、MDA、ROS（C、F组）值下降，心肌细胞活力、SOD值上升，作用普遍优于H组。在同等高、中、低浓度下，加入黄芪甲苷组的心肌细胞活力和LDH水平总体优于加入槲皮素组（如C、F组的心,肌细胞活力为0．454±0．018、0．471±0．017，LDH为2800±9、2312±52），但两组MDA、SOD和ROS值比较，差异无统计学意义（C、F组的ROS为16．0±5．3、22．4±8．7，P〉0．05）。结论 黄芪甲苷、槲皮素能有效保护缺氧心肌细胞，减轻损伤程度，其作用优于维生素E。黄芪甲苷的保护作用较槲皮素更好，但两者减轻细胞脂质过氧化损伤的作用差异不明显。     

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.     

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 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.     

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.     

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.     

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.