高温预处理对过氧化氢诱导大鼠心肌细胞线粒体金属硫蛋白表达的影响

目的 探讨高温预处理对过氧化氢(H2O2)诱导大鼠心肌细胞线粒体金属硫蛋白(MT)表达的影响.方法 采用随机数字表法,将体外培养的H9C2大鼠心肌细胞分为3组(n=6):正常对照组(C组)心肌细胞加入含血清DMEM培养基,置于37℃5％CO2培养箱中3 h;H2O2组加入含0.5mmol/L H2O2的无血清DMEM培养基,置于37℃5％CO2培养箱中孵育3h;高温预处理组(HTP组)加入含血清DMEM培养基,置于42℃恒温水浴lh,行高温预处理,然后在37℃5％CO2细胞培养箱中孵育12 h,去除DMEM培养基,随后处理同H2O2组.采用流式细胞术测定心肌细胞凋亡率;观察心肌细胞线粒体超微结构;采用Western blot法测定线粒体MT的表达.结果 与C组比较,H2O2组和HTP组细胞凋率升高,线粒体MT表达上调(P＜0.01);与H2O2组比较,HTP组细胞凋率降低,线粒体MT表达上调(P＜0.01).HTP组心肌细胞线粒体损伤较H2 O2组减轻.结论 高温预处理减轻H2O2诱导大鼠心肌细胞损伤的机制可能与上调线粒体MT表达,增强心肌内源性保护机制有关.     

二甲基乙二酰基甘氨酸对缺氧复氧诱导的肾小管上皮细胞损伤的保护作用及其机制

目的 通过脯氨酸羟化酶抑制剂二甲基乙二酰基甘氨酸（DMOG）稳定缺氧诱导因子1α（HIF-1α）表达,探讨其对缺氧复氧诱导的肾小管上皮细胞（HKC）损伤的保护作用及其机制。 方法 制作无糖缺氧复氧细胞损伤模型,用不同浓度的DMOG预处理,锥虫蓝染色和乳酸脱氢酶（LDH）活性方法检测细胞活力及损伤;Annexin V和PI染色流式细胞仪技术检测细胞凋亡;实时荧光定量PCR方法检测红细胞生成素（EPO）、热休克蛋白70（HSP70）和血红素氧合酶1（HO-1） mRNA的表达;Western印迹法检测HIF-1α、活性caspase-3和Bcl-2蛋白表达。 结果 正常情况下HKC细胞内几乎无HIF-1α蛋白表达,DMOG刺激6 h后HIF-1α蛋白及其靶基因EPO、HSP70和HO-1 mRNA表达均显著上调（均P ＜ 0.01）,且呈浓度依赖性。500 μmol/L或1 mmol/L DMOG预处理可明显改善缺氧复氧诱导的细胞损伤,表现为细胞存活率升高（95.6%±1.8%、96.1%±1.0%比 83.3%±3.1%）;培养上清液中LDH 活性下降;细胞凋亡减少（8.6%±2.7%、6.1%±2.3%比19.2%±4.0%）（均P ＜ 0.05）。另外,细胞内活性caspase-3蛋白表达显著下调,而Bcl-2蛋白表达则显著上调（均P ＜ 0.05）。 结论 DMOG预处理可稳定肾小管上皮细胞内HIF-1α表达,对缺氧复氧诱导的肾小管上皮细胞损伤具有一定保护作用。其机制可能与促进EPO、HSP70和HO-1表达,抑制caspase-3活化,上调Bcl-2表达有关。     

自噬和PI3K-Akt-mTOR信号转导通路在缺氧预处理对高糖心肌细胞缺氧/复氧损伤保护中的作用

目的 探讨自噬和磷脂酰肌醇3激酶（phosphatidylinositol 3 hydroxy kinase, PI3K）-蛋白激酶B（protein kinase B, Akt）-雷帕霉素靶蛋白（mammalian target of rapamycin, mTOR）信号转导通路在缺氧预处理（hypoxia preconditioning, HPC）对高糖心肌细胞缺氧/复氧（anoxia/reoxygenation, AR）损伤中的作用及机制。 方法 将采用高糖培养基培养72 h的心肌细胞用随机数字表法分为5组：空白对照组（S组）、AR损伤对照组（AR组）、HPC组、渥曼青霉素＋HPC组（Wo＋HPC组）、雷帕霉素＋HPC组（Ra＋HPC组）。采用乳酸脱氢酶（lactate dehydrogenase, LDH）检测试剂盒检测心肌细胞LDH漏出率,Annexin V/PI双染流式细胞术检测心肌细胞凋亡情况,蛋白印迹法检测心肌细胞微管相关蛋白1轻链3（microtubulesas sociated protein light, LC3）-Ⅱ、Beclin-1、mTOR、PI3K表达和磷酸化（phospho, p）蛋白激酶B/蛋白激酶B（p-Akt/Akt）比值。 结果 与AR组比较,Wo＋HPC组LDH漏出率、早期和晚期凋亡率降低（P〈0.05）,LC3-Ⅱ和Beclin-1表达降低（P〈0.05）,mTOR、PI3K表达和p-Akt/Akt比值升高（P〈0.05）。HPC组各指标与AR组比较,差异均无统计学意义（P〉0.05）。与HPC组比较,Wo＋HPC组LDH漏出率、早期和晚期凋亡率降低（P〈0.05）,Beclin-1表达降低（P〈0.05）,mTOR、PI3K表达和p-Akt/Akt比值升高（P〈0.05）。 结论 激活PI3K-Akt-mTOR信号转导通路抑制自噬可明显改善HPC对高糖心肌细胞AR损伤的保护作用。     

乌司他丁对骨骼肌细胞热应激条件下释放炎症因子的影响

目的：研究乌司他丁对于热应激条件下骨骼肌细胞（HMF）释放IL-6和TNF-α的影响.方法：人骨骼肌细胞株（HMF）培养后分为对照组（细胞置于37 ℃、5%CO2浓度培养箱中培养）、43 ℃热应激后0h组（细胞置于43 ℃细胞培养箱中培养1 h）;43 ℃热应激后6 h组（细胞置于43 ℃细胞培养箱中培养1 h,再置于37 ℃、5%CO2浓度培养箱中培养6 h）;43 ℃热应激＋乌司他丁后0 h组（细胞培养液中加入3 000 U/ml乌司他丁并置于43 ℃细胞培养箱中培养1 h）;43 ℃热应激＋乌司他丁后6 h组（细胞培养液中加入3 000 U/ml乌司他丁并置于43 ℃细胞培养箱中培养1 h,再置于37 ℃、5%CO2浓度培养箱中 6 h）.双抗体夹心ELISA 法测定各组培养上清中IL-6和TNF-α浓度.结果：43 ℃热应激0 h和6 h组,HMF释放 IL-6、TNF-α水平均较37 ℃对照组明显升高（P＜0.05）.HMF与乌司他丁共孵育可明显降低热应激1 h后37 ℃培养0 h和6 h时IL-6、TNF-α的释放水平.结论：乌司他丁可抑制热应激条件下HMF释放IL-6和TNF-α.     

热休克蛋白90对大鼠缺氧心肌细胞丝氨酸苏氨酸蛋白激酶表达的影响

目的探讨内源性热休克蛋白90（HSP90）在缺氧心肌细胞丝氨酸苏氨酸蛋白激酶（AKT）相关信号通路中的作用。方法建立新生Wistar大鼠心肌细胞缺氧模型，将细胞分为正常组、缺氧组、加入HSP90特异性阻断剂格尔德霉素后再缺氧组（格尔德霉素＋缺氧组）。于缺氧后1、3、6、12、24、48h用噻唑蓝法检测心肌细胞的活力；缺氧24h，原位缺口末端标记法检测心肌细胞凋亡指数（AI）；缺氧1、3、6、12、24h，蛋白质印迹法检测大鼠心肌细胞中内源性HSP90及AKT表达水平。结果（1）缺氧24、48h，缺氧组、格尔德霉素＋缺氧组细胞活力均较正常组明显下降（P〈0．05）；格尔德霉素＋缺氧组细胞活力缺氧12h即开始明显下降，缺氧48h时明显低于缺氧组（P〈0．05）。（2）缺氧24h，缺氧组细胞AI为（10．7±1．2）％，明显高于正常组[（1．9±0．3）％．P〈0．05]；格尔德霉素＋缺氧组细胞AI为（26、3±5．3）％，明显高于缺氧组（P〈0．01）。（3）缺氧12h，缺氧组心肌细胞内源性HSP90及AKT表达水平高于正常组与格尔德霉素＋缺氧组；缺氧24h，缺氧组有所下降．格尔德霉素＋缺氧组则下降更明显。结论内源性HSP90对维持心肌细胞的活力有重要作用．缺氧心肌细胞AKT表达水平可受内源性HSP90表达水平的影响。     

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。     

川芎嗪预先给药对胎鼠海马神经细胞缺氧/复氧时c-fos和HSP70表达的影响

目的 探讨川芎嗪预先给药对胎鼠海马神经细胞缺氧/复氧时c-fos和热休克蛋白70(HSP70)表达的影响.方法 胎鼠海马神经细胞培养鉴定后,随机分为5组(n=24):正常对照组(C组)、缺氧/复氧损伤组(A/R组)、不同浓度川芎嗪预先给药组(L组、M组和H组).C组不制备缺氧/复氧模型;A/R组、L组、M组和H组制备缺氧/复氧模型;L组、M组和H组加入川芎嗪,终浓度分别为60、200和800μg/ml,孵育1 h后制备缺氧/复氧模型.缺氧/复氧模型制备方法:海马神经细胞置入90%N2-10%CO2培养箱中孵育2 h诱导缺氧,然后放入37 ℃、5%CO2培养箱中复氧24 h.处理结束后测定海马神经细胞凋率、细胞活力、c-fos和HSP70的表达水平.结果 与C组比较,A/R组、L组和H组海马神经细胞活力降低,细胞凋亡率升高(P＜0.01);与A/R组比较,L组、M组和H组海马神经细胞活力升高,细胞凋亡率降低,c-fos表达下调,HSP70表达上调(P＜0.05);与L组比较,M组和H组海马神经细胞活力升高,细胞凋亡率降低,c-fos表达下调,HSP70表达上调(P＜0.05);与M组比较,H组细胞活力下降,细胞凋亡率升高,c-fos表达上调,HSP70表达下调(P＜0.01).结论川芎嗪预先给药抑制胎鼠海马神经细胞缺氧/复氧时细胞凋亡的机制可能与下调c-fos表达,上调HSP70表达有关.     

经高温处理后大鼠肝中热休克蛋白70的表达

目的　研究热休克蛋白 70 (HSP 70 )在高温处理后大鼠肝中不同时段的表达。方法　SD大鼠随机分成A组 (对照组 )和B组 (高温组 ,42℃ ,2 0min)。A组分别在麻醉后 4,8,2 0 ,3 6,72h取肝脏组织 ;B组置于自行设计的加热装置分别热处理后 4,8,2 4,3 6,72h取肝脏组织。用免疫组织化学、原位杂交方法检测A ,B两组不同时段HSP70表达 ,并对比其差异。结果　高温处理组各时段HSP70的表达差异有显著性 (P <0 .0 5 ) ;8～ 2 4h达最高峰 (P <0 .0 1)。高温处理后HSP70的表达明显高于对照组 (P <0 .0 5 )。结论　高温可诱导HSP70在大鼠肝中的高表达 ,处理后不同时段表达的量不同。     

谷氨酰胺对人肺泡Ⅱ型上皮细胞热休克蛋白70表达的影响

目的评价谷氨酰胺对人肺泡Ⅱ型上皮细胞系A549细胞热休克蛋白（HSP）70表达的影响。方法取人肺泡Ⅱ型上皮细胞系A549细胞,在不含谷氨酰胺的DMEM培养液中孵育24h作为空白对照组（C组）,43℃孵育1h、37℃恢复4h作为阳性对照组（PC组）,不同浓度（2、4、8、12和16 mmol/L）谷氨酰胺的DMEM培养液中孵育24h作为不同浓度谷氨酰胺诱导组（Gln2组、Gln4组、Gln8组、Gln（12）组和Gln（16）组）,8mmol/L谷氨酰胺的DMEM培养液中孵育不同时间（1、2、6、12、24和48 h）作为不同时间谷氨酰胺诱导组（T1组、T2组、T3组、T4组、T5组和T6组）。分别采用RT-PCR和Western blot法检测HSP70 mRNA和蛋白的表达。结果与C组比较,PC组和不同浓度谷氨酰胺诱导组人肺泡Ⅱ型上皮细胞系A549细胞HSPTO mRNA和蛋白的表达均升高,Gln8组HSP70 mRNA和蛋白表达水平高于Gln2组、Gln4组、Gln（12）组和Gln（16）组（P＜0．01）,而与PC组相比差异无统计学意义（P＞0．05）。与C组比较,PC组和不同时间谷氨酰胺诱导组HSP70 mRNA和蛋白的表达均升高,T5组HSP70 mRNA和蛋白表达水平高于T1组、T2组、T3组、T4组和T5组（P＜0．01）,而与PC组相比差异无统计学意义（P＞0．05）。结论谷氨酰胺可明显上调体外培养人肺泡Ⅱ型上皮细胞系A549细胞HSP70 mRNA和蛋白的表达,并呈浓度和时间依赖性。     

热休克蛋白70对肝硬化大鼠肝脏缺血再灌注损伤保护作用的研究

目的 探讨热休克蛋白70（HSP70）对肝硬化大鼠肝脏缺血再灌注损伤的保护作用。方法Wistar雄性大鼠用四氯化碳皮下注射制成肝硬化模型。分两组:IP组（缺血预处理组）,用 Pringle’s法阻断肝门15min后,恢复血供,关腹;C组（对照组）,只予以开、关腹。48h后,再次阻断肝门30min,恢复血供。用Western blotting法检测IP后6、24、48h肝组织中HSP70的表达水平;测再灌注1h血清生化酶（ALT、AST、LDH）水平;计算术后一周生存率,并行肝脏病理组织学检查。结果 IP组在缺血预处理后24-48hHSP70表达显著增强,呈高水平;而C组中在各时点HSP70均无表达增强。再灌注1h,IP组的ALT、AST、LDH水平显著低于C组（P<0.01或P<0.05,n=7）。术后一周生存率IP组（93.10％,n=29）明显高于C组（73.33％,n=30）（P<0.05）。缺血再灌注后1h,IP组的肝细胞损伤明显轻于C组。结论 HSP70能够减轻肝硬化大鼠肝脏缺血再灌注损伤,提高术后生存率。     

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.     

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.     

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.