NADPH氧化酶下调海马内微清蛋白表达在老年小鼠术后认知功能障碍中的作用

目的观察海马内微清蛋白(PV)表达变化在老年小鼠术后认知功能障碍(POCD)中的作用,并探讨磷酸酰胺腺嘌呤二核苷酸(NADPH)氧化酶是否参与其中。方法采用异氟醚麻醉+剖腹探查术建立POCD动物模型。雄性16月龄C57BL/6小鼠21只,随机均分为三组(n=7):对照+溶剂组(C+V组)、异氟醚麻醉+剖腹探查+溶剂组(POCD+V组)、异氟醚麻醉+剖腹探查+夹竹桃麻素组(POCD+A组)。POCD+A组术后1h腹腔注射夹竹桃麻素5mg/kg,其后每天注射一次直至术后第7天;其余两组注射等容量的溶剂。术后第6天行旷场实验和条件性恐惧实验训练,第7天在给予药物或溶剂后2h行条件性恐惧测试。行为学测试后2h取小鼠海马组织,采用Western blot检测PV、gp91phox、p22phox及羟基壬烯酸(4-HNE)的表达变化。结果三组小鼠总探索路程和中央格停留时间差异无统计学意义。与C+V组比较,POCD+V组在场景性条件恐惧测试中僵直时间明显缩短,海马PV表达明显下降,而gp91phox、p22phox和4-HNE表达明显升高(P0.05);与POCD+V组比较,POCD+A组在场景性条件恐惧测试中僵直时间明显延长,海马PV表达明显升高,gp91phox、p22phox和4-HNE表达明显降低(P0.05)。结论海马NADPH氧化酶活化介导PV表达降低可能参与老年小鼠POCD。     

七氟醚麻醉对大鼠海马α7烟碱型乙酰胆碱受体、胆碱酯酶和胆碱乙酰移位酶蛋白含量的影响

目的研究七氟醚麻醉对大鼠海马α7烟碱型乙酰胆碱受体(α7nAchR)、胆碱酯酶(AChE)、胆碱乙酰移位酶(ChaT)蛋白含量的影响。方法健康SD新生大鼠120只,雌雄不拘,1周龄,随机分为五组:空白组、空氧组、七氟醚组(SEV组)、α7nAchR激动剂组(PNU组)和α7nAchR拮抗剂组(MLA组),每组24只。空白组自由喂养;空氧组吸入60%的氧气即运载气体(1 L/min O_2+1 L/min空气)2 h;SEV组吸入3.4%七氟醚+运载气体2 h;PNU组单次腹腔注射α7nAchR激动剂PNU-282987,24 h后吸入3.4%七氟醚+运载气体2 h;MLA组单次腹腔注射α7nAchR拮抗剂甲基牛扁亭,24 h后吸入3.4%七氟醚+运载气体2 h。麻醉清醒后2 h、1周、4周取海马组织,采用Western blot法测定α7nAchR、AChE、ChaT蛋白含量。结果麻醉清醒后2 h SEV组、PNU组、MLA组α7nAchR蛋白含量明显低于空氧组(P0.05);PNU组、MLA组AChE蛋白含量明显高于空氧组(P0.05);SEV组、PNU组、MLA组ChaT蛋白含量明显低于空氧组(P0.05)。麻醉清醒后1周空白组、SEV组、PNU组海马中α7nAchR蛋白含量明显高于空氧组(P0.05),MLA组α7nAchR蛋白含量明显低于空氧组(P0.05);空白组、PNU组AChE蛋白含量明显高于空氧组(P0.05);空白组ChaT蛋白含量明显高于空氧组,SEV组ChaT蛋白含量明显低于空氧组(P0.05)。麻醉清醒后4周五组AChE蛋白含量差异无统计学意义;SEV组α7nAchR蛋白含量明显高于空白组,PUN组和MLA组明显低于空白组(P0.05);空白组、SEV组和PNU组ChaT蛋白含量明显低于空氧组,MLA组明显高于空氧组(P0.05)。结论吸入七氟醚后能抑制ChaT、α7nAChR;对AChE并无直接作用;α7nAChR激动剂能有效缓解吸入七氟醚对α7nAChR、ChaT抑制作用,并在1周左右达到高峰;氧浓度在60%左右能增加α7nAChR蛋白含量,一定程度对抗七氟醚抑制作用。     

麻醉浓度七氟醚对TM3小鼠睾丸间质细胞活力的影响

目的 探讨麻醉浓度七氟醚对TM3小鼠睾丸间质细胞活力的影响.方法 采用随机数字表法,将TM3小鼠睾丸间质细胞株随机分为3组,每组24皿:对照组(C组)、2％七氟醚组和5％七氟醚组(SEV1,2组).将细胞放置于37℃的密闭培养箱中,通入七氟醚,维持浓度2％(SEV1组)或5％(SEV2组).C组仅给予95％空气和5％CO2的混合气体.于七氟醚孵育2、4、6 h(T1-3)时采用光学双目倒置显微镜观察细胞形态,并采用CCK-8法测定细胞活力.于七氟醚孵育6h后,收集C组和SEV2组细胞,应用基因芯片筛选差异基因.结果 与C组和SEV1组比较,SEV2组T3时细胞活力明显降低(P＜0.05),T1.2时差异无统计学意义(P＞ 0.05);SEV1组和C组各时点细胞活力比较差异无统计学意义(P＞0.05).C组和SEV1组细胞形态未见异常,SEV2组细胞发生形态学改变.与C组比较,SEV2组差异表达的基因有45个,差异倍数最大的有:前列腺素内过氧化物酶2基因、趋化因子配体2基因和双特异性磷酸酶l基因.结论 麻醉浓度七氟醚可抑制TM3小鼠睾丸间质细胞的活力,且与浓度有关,其机制可能与前列腺素内过氧化物酶2基因、趋化因子配体2基因和双特异性磷酸酶1基因表达异常有关.     

异氟醚和七氟醚麻醉对患者心率变异性的影响

目的研究异氟醚和七氟醚麻醉对患者心率变异性(HRV)的影响。方法60例择期颅脑手术患者,用动态心电图仪记录麻醉诱导前、插管后10 min、停药时、停药后1、2 h和4 h的HRV。结果ISO1组(异氟醚,年龄<60岁)和ISO2组(异氟醚,年龄≥60岁)插管后10 min、停药时、停药后1、2 h的低频功率(LF)、高频功率(HF)值均显著低于麻醉诱导前(P<0.05)。SEV1组(七氟醚,年龄<60岁)和SEV2组(七氟醚,年龄≥60岁)的LF、HF值在插管后10 min、停药时、停药后1 h均显著低于麻醉诱导前(P<0.05)。ISO组插管后各时点的LF、HF值均显著低于SEV组(P<0.05)。结论异氟醚对患者的交感神经和迷走神经都有明显的抑制作用,而对于交感神经和副交感神经活性的均衡性没有显著的影响。异氟醚对于交感神经和迷走神经的抑制作用比七氟醚更为明显。     

七氟醚减轻大鼠呼吸机相关性肺损伤

目的 探讨七氟醚对大鼠呼吸机相关性肺损伤（VILI）的影响并探讨其可能机制。
方法 健康SPF级雄性SD大鼠36只，6～8周龄，体重220～280 g。随机分为三组：对照组（C组）、VILI组（V组）和七氟醚组（S组），每组12只。大鼠给予1%戊巴比妥钠40 mg/kg麻醉后行气管切开插管术，C组自主呼吸4 h，V组和S组插管后机械通气4 h，S组机械通气期间吸入2%七氟醚4 h。通气参数：V_T 20 ml/kg，RR 80次/分，I∶E 1∶1，FiO₂ 21%，PEEP 0 cmH₂O。机械通气结束时采集股动脉血测定PaO₂。处死大鼠，取肺组织和支气管肺泡灌洗液（BALF），计算肺组织湿/干重比值（W/D），采用ELISA法检测BALF中白细胞介素（IL）-1β、IL-18浓度，二氯荧光黄双乙酸盐法检测BALF中肺泡巨噬细胞活性氧（ROS）水平，Western blot法及qRT-PCR法检测肺组织NF-E2相关因子2（Nrf2）、NLRP3、凋亡相关斑点样蛋白（ASC）、caspase-1蛋白含量及其mRNA表达量，观察肺组织病理学改变并进行肺损伤评分。
结果 与C组比较，V组和S组机械通气结束时PaO₂、肺组织Nrf2蛋白含量及其mRNA表达量明显降低（P<0.05），肺组织W/D、BALF中IL-1β、IL-18浓度、BALF中肺泡巨噬细胞ROS水平、肺组织NLRP3、ASC、caspase-1蛋白含量及其mRNA表达量、肺损伤评分明显升高（P<0.05）。与V组比较，S组机械通气结束时PaO₂、肺组织Nrf2蛋白含量及其mRNA表达量明显升高（P<0.05），肺组织W/D、BALF中IL-1β、IL-18浓度、BALF中肺泡巨噬细胞ROS水平、肺组织NLRP3、ASC、caspase-1蛋白含量及其mRNA表达量、肺损伤评分明显降低（P<0.05）。
结论 七氟醚可能通过上调Nrf2和下调NLRP3炎性小体的表达，减轻肺组织氧化应激反应和炎症反应，减轻大鼠呼吸机相关性肺损伤。     

七氟醚后处理对大鼠脑缺血-再灌注时氧化应激和炎症反应的影响

目的评价七氟醚后处理对大鼠脑缺血-再灌注时氧化应激及炎症反应的影响,以探讨其脑保护机制。方法健康雄性清洁级SD大鼠36只,12~14周龄,体重220~260g,采用随机数字表法分为假手术组(Sham组)、脑缺血-再灌注组(IR组)和脑缺血-再灌注+七氟醚后处理组(SPC组),每组12只。制备大鼠脑缺血-再灌注损伤模型,缺血30min后再灌注24h。Sham组不阻塞大脑中动脉;IR组:建立脑缺血-再灌注损伤模型;SPC组于再灌注即刻给予2.6%七氟醚吸入15min。再灌注末处死各组大鼠,断头取出脑组织。采用Western blot法检测Iba-1和HO-1蛋白含量;并测定脑组织中活性氧(ROS)含量,丙二醛(MDA)、TNF-α、IL-1β浓度和超氧化物歧化酶(SOD)活性。结果 IR组和SPC组脑皮质Iba-1蛋白含量明显高于Sham组(P0.05),SPC组Iba-1蛋白含量明显低于IR组(P0.05)。与Sham组比较,IR组和SPC组ROS含量和MDA、TNF-α、IL-1β浓度明显升高,SOD活性和HO-1蛋白含量明显降低(P0.05)。SPC组ROS含量和MDA、TNF-α、IL-1β浓度明显低于IR组,SPC组SOD活性和HO-1蛋白含量明显高于IR组(P0.05)。结论七氟醚后处理能抑制脑缺血-再灌注时诱发的小胶质细胞激活,减轻脑组织氧化应激及炎症反应,从而减轻脑缺血-再灌注损伤,发挥其脑保护作用。     

七氟醚预处理对小鼠Lewis肺癌细胞肺转移的抑制作用

目的观察七氟醚预处理对小鼠Lewis肺癌细胞肺转移的影响。方法小鼠Lewis肺癌细胞接种于培养板,培养24h后,采用随机数字表法,将其随机分为四组:对照组(CC组)、1%七氟醚组(SC1组)、2%七氟醚组(SC2组)和3%七氟醚组(SC3组)。CC组不接受七氟醚处理,SC1~3组细胞分别用1%、2%、3%七氟醚处理4h,继续培养24h。采用Transwell法检测细胞侵袭能力,细胞划痕实验检测细胞迁移能力;采用ELISA法检测细胞MMP-2和MMP-9蛋白表达。32只C57BL/6小鼠随机分为四组:对照组(CM组)、1%七氟醚组(SM1组)、2%七氟醚组(SM2组)和3%七氟醚组(SM3组),每组8只。取SC1~3组七氟醚预处理后的Lewis肺癌细胞悬液0.1ml(2×107个/ml),分别给SM1~3组小鼠尾静脉注射,CM组小鼠注射等体积的CC组细胞悬液。3周后观察肺部转移灶,计算肺转移抑制率。结果 SC1~3组细胞侵袭能力和迁移能力明显低于CC组,且SC1组SC2组SC3组(P0.05);SC1~3组MMP-2和MMP-9浓度明显低于CC组,且SC1组SC2组SC3组(P0.05);SM1~3组肺转移抑制率明显高于CM组,且SM1组SM2组SM3组(P0.05)。结论七氟醚预处理小鼠Lewis肺癌细胞可抑制其在小鼠体内的肺转移,此效应可能与下调小鼠Lewis肺癌细胞MMP-2和MMP-9表达有关。     

七氟醚对内毒素致急性肺损伤鼠肺泡毛细血管膜通透性的影响

目的　探讨七氟醚对内毒素致急性肺损伤鼠肺泡毛细血管膜通透性和肺泡灌洗液内炎性细胞的影响。方法　 4 8只Wistar大鼠 ,麻醉后静注伊万斯蓝 5 0mg/kg后 ,随机分为 4组 ,每组 12只。对照组 :股静脉注射生理盐水 1 2ml后机械通气 4h ;内毒素组 :股静脉注射内毒素 5mg/kg后机械通气 4h ;七氟醚 1L组和七氟醚 2L组 :股静脉注射内毒素 5mg/kg后机械通气 ,分别吸入肺泡气最低有效浓度 (MAC)为 1 0和 1 5的七氟醚 4h。 4h后取肺组织测定 :病理形态学积分 ,肺湿 /干重比 ,肺水含量 ,肺通透指数 ,伊万斯蓝含量和肺泡灌洗液内炎性细胞总数及百分比。结果　七氟醚1L组肺通透指数、伊万斯蓝含量、病理形态学积分分别由 4 6 8± 0 82 ,( 112 2 1± 11 4 4 )ng/mg ,9 17± 0 90下降到 3 98± 0 5 0 ,( 92 85± 11 80 )ng/mg ,7 5 0± 0 96 ;七氟醚 2L组下降到 3 91±0 34,( 96 33± 8 79)ng/mg ,7 6 7± 0 75。结论　 1 0和 1 5MAC七氟醚可降低内毒素所致急性肺损伤肺泡毛细血管膜通透性 ,使肺组织病理损伤减轻     

活性氧在七氟醚预处理减轻大鼠海马脑片氧糖缺失损伤中的作用

目的 评价活性氧(ROS)在七氟醚预处理减轻大鼠海马脑片氧糖缺失损伤中的作用.方法 雄性SD大鼠,体重80～100 g,断头处死,剥离海马,符合标准的40片海马脑片随机分为4组(n=10):氧糖缺失组(OGD组)、4%七氟醚预处理组(Sevo组)、ROS清除剂组(MPG组)和4%七氟醚预处理+ROS清除剂组(SM组),采用脑片灌流及电生理技术,细胞外记录海马CAI区缺氧期间和复氧1 h期间的顺向群锋电位(OPS);采用2,3,5-三苯基氯化四氮唑(TYC)染色定量比色法分析脑片损伤程度.结果 与OGD组相比,Sevo组OPS消失时间缩短,OPS恢复程度、OPS恢复率均升高,组织损伤百分率降低(P<0.01);与Sevo组相比,MPG组和SM组OPS消失时间缩短,OPS恢复程度、OPS恢复率降低,组织损伤百分率升高(P相似文献   

幼猪机械通气中异氟醚或七氟醚混合一氧化氮吸入的安全性

目的研究吸入异氟醚或七氟醚混合一氧化氮(NO)在幼猪机械通气中的安全性。方法36头幼猪随机分为6组:Ⅰ组(对照组):单纯机械通气;Ⅱ组(NO组):吸入20ppmNO;Ⅲ组(异氟醚组):吸入1.3MAC异氟醚;Ⅳ组(异氟醚 NO组):吸入1.3MAC异氟醚及20ppmNO;Ⅴ组(七氟醚组)吸入1.3MAC七氟醚;Ⅵ组(七氟醚 NO组)吸入1.3MAC七氟醚及20ppmNO。用麻醉机行间歇正压通气4h,测定各组机械通气前、机械通气1、2、3、4h(T0、T1、T2、T3、T4)的呼吸频率(RR)、呼吸系统总顺应性(Crs)、气道压力(Paw)、潮气量(VT)、分钟通气量(MV)以及呼末二氧化碳分压(PETCO2);测定T0、T2、T4时点动脉血高铁血红蛋白(MetHb)和亚硝酸根(NO2-/NO3-)水平;处死动物后比较各组肺组织湿/干重比、支气管肺泡灌洗液(BALF)中饱和磷脂/总磷脂(DSPC/TPL)及饱和磷脂,总蛋白(DSPC/TP)、肺表面张力和白细胞计数,并行肺组织损伤评分。结果Ⅲ、Ⅳ、Ⅴ、Ⅵ组BALF中DSPC/TP及肺表面张力较Ⅰ组下降(P<0.05),通气结束时Crs较通气前下降(P<0.05),而Ⅱ组无显著性变化(P>0.05);与通气前比较,各组通气结束时MetHb与:NO2-/NO3-水平无变化,各组BALF中白细胞计数、肺组织损伤评分、肺泡扩张度和湿/干重比之间比较差异无统计学意义。结论1.3MAC异氟醚或七氟醚混合20ppmNO吸入可以安全用     

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.     

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.     

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.     

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.     

Is the recovery profile of mivacurium independent of the rate of decay of its plasma concentration in patients with normal plasma cholinesterase activity?

Background: The duration of action of muscle relaxants is poorly correlated to the rate of decay of their plasma concentration. The plasma concentration of mivacurium may rapidly decrease below its active concentration because of the extensive hydrolysis of mivacurium. By inflating a tourniquet on one upper limb for 3 min after the administration of atracurium, mivacurium or vecuronium, we studied the influence of the initial decline of their plasma concentration on their effect. Methods: In 50 patients anaesthetised with thiopental, isoflurane and fentanyl, the effect of bolus doses of 0.15 or 0.25 mg . kg^?1 mivacurium (MIV 15, MIV 25), 0.3 or 0.5 mg . kg^?1 atracurium (ATR 30, ATR 50) and 0.06 or 0.1 mg . kg^?1 vecuronium (VEC 06, VEC 10) were measured on both arms (evoked response of the adductor pollicis to train-of-four stimulation every 12 s), a tourniquet being applied on one arm just before and during 3 min after the muscle relaxant bolus. Results: Tourniquet inflation of 3 min almost abolished the neuromuscular effect of mivacurium. In the vecuronium groups and in the ATR 50 group, tourniquet inflation did not modify the maximum degree of depression of the twitch response. Also, the duration of action of vecuronium was unaffected by the tourniquet. In the ATR 30 group, times to return of the twitch response to 25% (duration 25%) and 75% (duration 75%) of control response were significantly shorter in the cuffed arm, 23 min vs 27 min, and 41 min vs 45 min, respectively. In the ATR 50 group, only duration 25% was significantly shorter in the cuffed arm (41 min vs 45 min). Conclusion: The results suggest that the rate of decline of the plasma concentration of mivacurium is so rapid, that a very low and almost clinically ineffective concentration is present as soon as 3 min after its administration. The results also indicate that the recovery from a mivacurium-induced neuromuscular blockade is not influenced by the rate of decay of its plasma concentration in patients with genotypically normal plasma cholinesterase.     

Membranes in Artificial Organs

Abstract: Membrane processes play a pivotal and enabling role in modern replacement therapy for acute and chronic organ failure and in the management of immunologic diseases. In fact, virtually all contemporary extracorporeal blood purification methods employ membrane devices, and the next generation of artificial organs and tissue engineering therapies are almost certain to be similarly grounded in membrane technology. In this short essay, we comment on the similarities and differences among synthetic membranes and their natural counterparts and also provide a critical overview of the demographics and technology of hemodialysis, hemofiltration, apheresis, oxygenation, and emerging membrane technologies and applications.     

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.     

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.