异丙酚对乳鼠心肌细胞氧化损伤时线粒体功能的影响

目的 评价异丙酚对乳鼠心肌细胞氧化损伤时线粒体功能的影响.方法 SD乳鼠20只,分离乳鼠心肌细胞,接种于96孔培养板原代培养48 h,随机分为5组,每组32孔,对照组(C组):继续培养4 h;氧化损伤组(OI组):加入叔丁基过氧化氢,终浓度为100 μmol/L,孵育4 h;异丙酚1 μmol/L组、10 μmol/L组和30 μmol/L组(P1-3组):加入叔丁基过氧化氢,终浓度为100 μmol/L,同时加入异丙酚,终浓度分别为1、10、30,μmol/L,孵育4 h.于细胞培养或孵育4 h时,测定上清液乳酸脱氢酶(LDH)活性,细胞谷胱甘肽(GSH)、丙二醛(MDA)含量和超氧化物岐化酶(SOD)活性、心肌细胞线粒体活力、线粒体膜电位和心肌细胞凋亡率.结果 与C组比较,其余4组上清液LDH活性、心肌细胞MDA含量、凋亡率升高,心肌细胞线粒体活力、膜电位降低、心肌细胞GSH含量、SOD活性降低(P<0.05);与OI组比较,P2,3组上清液LDH活性、心肌细胞MDA含量、凋亡率降低,心肌细胞线粒体活力、膜电位升高,P3组心肌细胞GSH含量、SOD活性升高(P<0.05),P1组上述指标差异无统计学意义(P>0.05);P2组与P3组上述指标比较差异无统计学意义(P>0.05).结论 异丙酚减轻心肌细胞氧化损伤的机制与改善线粒体功能、抑制细胞凋亡有关.     

高糖诱发施万细胞损伤时自噬与Nrf2信号通路的关系

目的探讨高糖诱发施万细胞损伤时自噬与核因子E2相关受体2(Nrf2)信号通路的关系。方法将原代细胞株RSC96体外培养制成单细胞原液,分别接种于96孔板(1×104个/ml,200 μl/孔)或6孔板(1×106个/ml,2 ml/孔),培养48 h。采用随机数字表法分为3组(n=25):对照组(C组)、高糖组(H组)和高糖+自噬激动剂雷帕霉素组(H+RAP组)。C组在正常培养基中培养;H组培养基中加入50 mmol/L葡萄糖;H+RAP组培养基中加入50 mmol/L葡萄糖和5 μmol/L雷帕霉素。孵育48 h时,倒置显微镜下观察细胞生长情况,采用MTT法测定细胞活力,流式细胞术检测细胞凋亡率,硫代巴比妥酸法测定MDA含量,黄嘌呤氧化酶法测定SOD活性,Western blot法检测Nrf2、P62和微管相关蛋白1轻链3Ⅱ(LC3Ⅱ)的表达水平。结果与C组比较,H组和H+RAP组细胞活力和SOD活性降低,细胞凋亡率和MDA含量升高,Nrf2、P62和LC3Ⅱ表达上调(P<0.05);与H组比较,H+RAP组细胞活力和SOD活性升高,细胞凋亡率和MDA含量降低,Nrf2和LC3...     

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。     

异丙酚对布比卡因致PC12细胞毒性时细胞Ca2+浓度和一氧化氮合酶活性的影响

目的 评价异丙酚对布比卡因致PC12细胞毒性时细胞Ca2+浓度和一氧化氮合酶(NOS)活性的影响.方法 PC12细胞悬液(105/ml)随机分成4组:对照组(C组)、异丙酚组(P组)、布比卡因组(B组)和异丙酚+布比卡因组(PB组),每组PC12细胞分别接种于36孔板(每孔1 ml,每组9孔)、激光共聚焦显微镜专用培养皿(每皿1 ml,每组6皿)和24孔板(每孔 1 ml,每组6孔).C组加入D-Hank液500 μl;P组加入异丙酚至终浓度为2 mmol/L;B组加入布比卡因至终浓度为0.09 mmol/L;PB组同时加入异丙酚和布比卡因,终浓度分别为2 mmol/L和0.09 mmol/L.于36孔板中孵育24 h后测定PC12细胞凋亡率;于激光共聚焦显微镜专用培养皿中孵育6、24 h时,测定PC12细胞游离Ca2+浓度;于24孔板中孵育6、24 h时测定细胞NOS活性.结果 与C组相比,B组和PB组PC12细胞游离Ca2+浓度、NOS活性和凋亡率均升高(P<0.01),P组上述指标差异无统计学意义(P>0.05);与B组相比,PB组PC12细胞游离Ca2+浓度、NOS活性和凋亡率均降低(P<0.05).结论 在细胞水平,异祆丙酚可能通过抑制NOS活性和钙超载,减轻布比卡因诱导的神经毒性.     

PKC在缺氧预处理和去甲肾上腺素预处理减轻乳鼠心肌细胞缺氧复氧损伤中的作用

目的 评价蛋白激酶C(PKC)在缺氧预处理和去甲肾上腺素预处理减轻乳鼠心肌细胞缺氧复氧损伤中的作用.方法 原代培养乳鼠心肌细胞,随机分为6组(n=25):对照组(Ⅰ组)常规培养;缺氧复氧组(Ⅱ组)细胞缺氧3 h,复氧1 h;缺氧预处理组(Ⅲ组)缺氧20 min,复氧20 min后制备缺氧复氧模型;去甲肾上腺素预处理组(Ⅳ组)细胞经终浓度为10-7 mol/L去甲肾上腺素孵育30 min后,去除去甲肾上腺素,再行缺氧复氧;H7+缺氧预处理组(Ⅴ组)细胞经终浓度为5×10-5 mol/L的H7孵育10 min后,去除H7,其余操作同Ⅲ组;H7+去甲肾上腺素预处理组(Ⅵ组)细胞经终浓度为5×10-5 mol/L的H7(PKC活性抑制剂)孵育10 min后,去除H7,其余操作同Ⅳ组.复氧结束后,测定心肌细胞存活率、培养液乳酸脱氢酶(LDH)、肌酸激酶(CK)活性和心肌细胞MDA含量和SOD活性.结果 与Ⅰ组比较,Ⅱ组细胞存活率和SOD活性降低,LDH、CK的活性及MDA含量升高(P＜0.01).与Ⅱ组比较,Ⅲ组和Ⅳ组细胞存活率和SOD活性升高,LDH、CK活性及MDA含量降低(P＜0.01).与Ⅲ组比较,Ⅴ组细胞存活率和SOD活性降低,LDH、CK活性及MDA含量升高(P＜0.01).与Ⅳ组比较,Ⅵ组细胞存活率和SOD活性降低,LDH、CK活性及MDA含量升高(P＜0.05).结论 PKC激活参与了缺氧预处理与去甲肾上腺素预处理减轻乳鼠心肌细胞缺氧复氧损伤.     

氯胺酮对谷氨酸引起神经元样嗜铬细胞瘤细胞株凋亡的影响

目的 观察氯胺酮对谷氨酸引起神经元样嗜铬细胞瘤(PC12)细胞株凋亡的影响。方法PC12细胞株分别以2×103/孔和1×105/ml密度接种于96孔细胞培养板和60 mm细胞培养皿中,置于培养基,培养基中加10 nmol/L神经生长因子(7S-NGF),96孔细胞培养板和60 mm细胞培养皿的细胞均随机分为五组,A组暴露于20 mmol/L谷氨酸中,B组暴露于20 mmol/L谷氨酸 0.1 mmol/L氯胺酮(氯胺酮比谷氨酸提前1 min 加入)中,C组暴露于20 mmol/L 谷氨酸 1.0 mmol/L氯胺酮中,D组暴露于20 mmol/L 谷氨酸 100 μmol/L D-2-氨基-5-膦酸基戊酸(D-AP5)(细胞与D-AP5提前孵育2h)中,E组暴露于等容积的不含7S-NGF的新鲜培养液中,采用MTT法测定细胞培养板中PC细胞的细胞活力,采用死端比色TUNEL系统细胞检测培养皿中PC12细胞株的凋亡率。结果 A组、B组、C组和D组细胞活力分别为:37％±6％、65％±7％、99％±10％、90％±22％,与A组比较,B组、C组、D组细胞活力均升高(P<0.05或0.01)。A组、C组、D组、E组凋亡细胞率分别为66％±10％、20％±6％、22±7％、3.2％±1.8％,与A组比较,C组、D组、E组细胞凋亡率明显降低(P<0.01)。结论 氯胺酮通过抑制谷氨酸引起的神经元样PC12细胞株凋亡而发挥神经保护作用。     

ROS/GADD153蛋白在血管紧张素Ⅱ诱导心肌细胞凋亡中的作用

目的 探讨活性氧簇(ROS)/GADD153蛋白在血管紧张素Ⅱ(AngⅡ)诱导心肌细胞凋亡中的作用.方法 体外培养乳鼠心肌细胞,随机分为9组(n=5),Ⅰ组(C组)常规心肌细胞培养,不予其他处理;Ⅱ组(AngⅡ6组)给予100 nmol/L AngⅡ,孵育6 h;Ⅲ组(AnsⅡ12组)给予100 nmol/L AngⅡ,孵育12 h;Ⅳ组(ArtsⅡ24组)给予100 nmol/L Ang Ⅱ,孵育24 h;V组[N-乙酰-L半胱氨酸(NAC)+AngⅡ组]预先给予抗氧化剂NAC 5 mmol/L,2 h后给予100 nmol/L Ang Ⅱ,孵育24 h;Ⅵ组(NAC组)仅给予NAC 5 mmol/L,孵育24 h;Ⅶ组(anti-ODN组)GADD153反义寡核苷酸10 μmol/L转染24 h后,加入100nmoFL AngⅡ,孵育24 h;Ⅷ组(mis-ODN组)GADDl53错义寡核苷酸10 μmol/L转染24 h后,加入100nmol/L Ang Ⅱ,孵育24 h;Ⅸ组(脂质体对照组)加入等容量转染试剂,孵育24 h.检测细胞活力、细胞内ROS产量、细胞凋亡率及GADD153蛋白表达水平.结果 与C组相比,AngⅡ6组、AngⅡ12组、AngⅡ24组细胞活力降低,细胞凋亡率、ROS产量及GADD153蛋白表达升高,且呈时间依赖性(P＜0.05);与AngⅡ24组比较,NAC+AngⅡ组和anti-ODN组细胞活力升高,细胞凋亡率、ROS产量及GADD153蛋白表达降低(P＜0.05).结论 AugⅡ通过增加ROS产量,诱导GADD153蛋白表达上调,从而导致心肌细胞凋亡的发生.     

氯胺酮复合咪达唑仑对谷氨酸诱导PC12细胞凋亡的影响

目的 探讨氯胺酮复合咪达唑仑对谷氨酸诱导PC12细胞凋亡的影响.方法 诱导分化4 d的神经元样PC12细胞随机分为5组:对照组(c组);谷氨酸组(Glu组)加入20 mmol/L谷氨酸;氯胺酮组(K组)、咪达唑仑组(M组)、氯胺酮+咪达唑仑组(K+M组)均加入20 mmol/L谷氨酸后,分别加入50 μmol/L氯胺酮、1μmol/L咪达唑仑、50 μmol/L氯胺酮+1 μmol/L咪达唑仑.各组细胞继续培养24 h后采用MTT法检测细胞活力,Hoechst33258核染色法及Annexin V-FITC/PI双染流式细胞术检测凋亡细胞.结果 与C组比较,Glu组细胞活力降低,细胞凋亡率升高(P<0.01);与Glu组比较,K组和M组细胞活力升高,细胞凋亡率降低(P<0.05);与K组和M组比较,K+M组细胞活力升高,细胞凋亡率降低(P<0.05);K组和M组细胞活力及细胞凋亡率差异无统计学意义(P>0.05).结论 氯胺酮复合咪达唑仑可更有效地抑制谷氨酸诱导PC12细胞凋亡.     

琥珀酸对人外周血中性粒细胞凋亡的影响

目的 了解琥珀酸对人外周血中性粒细胞(PMN)凋亡的影响,探讨其致病机制.方法 体外孵育PMN,将PMN浓度调至5×106个/ml.在细胞中加入琥珀酸刺激,根据所加琥珀酸浓度分为5、10、20、30 mmol/L琥珀酸组;对照组加入常规培养液.取各组细胞培养上清液,检测其活性氧含量.5、20 mmol/L琥珀酸组细胞于处理前及处理后2、4、6、8、10 h分别取细胞悬液1 ml,行半胱氨酸天冬氨酸蛋白酶3(caspase-3)活性及细胞凋亡率检测.结果 5、10、20、30 mmol/L琥珀酸组活性氧含量(0.437±0.056、0.432±0.024、0.395±0.049、0.386±0.010)均低于对照组(0.505±0.028,P＜0.05).随着孵育时间延长,各组细胞caspase-3活性均逐渐增加,但与对照组比较,5 mmol/L琥珀酸组caspase-3活性降低,20 mmol/L琥珀酸组则升高(P＜0.05).对照组细胞处理前凋亡率为(6.1±1.1)%,处理后2 h为(13.2±2.0)%,10 h达(27.7±3.7)%;5 mmol/L琥珀酸组细胞凋亡率除处理后4 h外其余时相点均低于对照组(P＜0.05);20 mmol/L琥珀酸组细胞处理后4～10 h凋亡率均高于对照组(P＜0.05).结论 低浓度琥珀酸抑制PMN凋亡,而高浓度琥珀酸可促进PMN凋亡.细菌感染时,通过代谢产物琥珀酸抑制PMN免疫功能.     

Fas/FasL在罗哌卡因致PC12细胞凋亡中的表达

目的检测Fas、FasL在罗哌卡因诱导PC12细胞凋亡中表达的变化,探讨罗哌卡因的神经毒性机制。方法采用不同浓度罗哌卡因(0.1、0.5、1、2、4 mmol/L)处理PC12细胞24 h以建立细胞的神经毒性模型,CCK-8法测定细胞活力。最终将细胞随机分为三组:0.5 mmol/L组、2mmol/L组和正常对照组。各组细胞培养24 h后用光学显微镜观察细胞形态学变化(加上1 mmol/L组),流式细胞仪检测细胞凋亡,免疫荧光检测Fas、FasL表达。结果与正常对照组比较,0.5 mmol/L组和2 mmol/L组细胞活力明显降低(P0.05),细胞形态明显异常(包括1 mmol/L组),凋亡率明显升高(P0.05),Fas、FasL表达明显增强(P0.05);与0.5 mmol/L组比较,2 mmol/L组细胞凋亡率和Fas、FasL表达明显增加(P0.05)。结论罗哌卡因可诱导PC12细胞凋亡,其机制可能与Fas/FasL上调有关。     

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.