七氟醚后处理对大鼠脑缺血-再灌注损伤海马血红素氧合酶-1蛋白表达的影响

目的 探讨七氟醚后处理对大鼠脑缺血-再灌注损伤的保护作用及血红素氧合酶-1(HO-1)在其中的作用.方法 清洁级雄性SD大鼠40只,体重230～270 g,随机均分为五组:假手术组(C组),缺血-再灌注组(IR组),七氟醚组(S组),七氟醚+锌原卟啉Ⅸ(Znpp)组(SZ组)和溶剂对照组(SD组).采用双侧颈总动脉夹闭合并取血降压再回输的方法制备脑缺血-再灌注损伤模型,S组再灌注前5 min气管插管,吸入1MAC七氟醚15 min; SZ组模型制备前腹腔注射Znpp45μmol/kg,溶于二甲基亚砜(DMSO)0.5 ml; SD组模型制备前腹腔注射DMSO 0.5 ml.所有大鼠再灌注24 h后处死,取海马.光镜下观察各组海马病理学变化,检测海马超氧化物歧化酶(SOD)活性、丙二醛(MDA)含量和HO-1蛋白表达.结果 与C组比较,其余四组SOD活性明显降低(P＜0.05),MDA含量明显升高(P＜0.05),SZ组HO-1蛋白表达差异无统计学意义,IR、S和SD组HO-1蛋白表达明显升高(P＜0.05).与IR组比较,S组和SD组SOD活性和HO-1蛋白表达明显升高(P＜0.05),MDA含量明显降低(P＜0.05),SZ组HO-1蛋白表达明显降低(P＜0.05).光镜下S组和SD组海马病理学损伤较IR组和SZ组减轻.结论 七氟醚后处理对大鼠脑缺血-再灌注损伤有保护作用,其作用机制可能与七氟醚上调脑组织中HO-1蛋白表达有关.     

七氟醚对肢体缺血再灌注大鼠肝损伤的影响

目的探讨七氟醚对肢体缺血再灌注大鼠肝损伤的影响。方法健康SD大鼠24只,体重200～250g,随机分为3组,各8只:假手术组(Sham组),只进行手术操作不做其他处理;肢体缺血再灌注组(IR组),双后肢缺血4h、再灌注6h;七氟醚组(S组)于再灌注前吸入2.5%七氟醚6h。IR、Sham组只吸入氧气。实验结束断头处死大鼠,于下腔静脉取血测定血清丙氨酸氨基转移酶(ALT)、天冬氨酸氨基转移酶(AST)的含量。摘取肝脏测定肝组织匀浆超氧化物歧化酶(SOD)、丙二醛(MDA)、肿瘤坏死因子α(TNF-α)和白细胞介素6(IL-6)的含量,光学显微镜下观察组织病理学结果。结果与Sham组比较,IR组和S组ALT、AST、MDA、TNF-α和IL-6含量升高,SOD含量降低(P<0.01),肝组织损伤明显;与IR组比较,S组ALT、AST、MDA、TNF-α和IL-6含量降低,SOD含量升高(P<0.05),肝组织损伤减轻。结论七氟醚对肢体缺血再灌注大鼠肝损伤具有一定程度的保护作用,其机制可能与其减少氧自由基的释放和抑制炎症反应有关。     

七氟醚预处理联合后处理对大鼠心肌缺血-再灌注损伤的影响

目的 探讨七氟醚预处理联合后处理对大鼠缺血-再灌注损伤心肌的保护作用及其相关机制.方法 清洁级成年雄性SD大鼠40只,体重230～270 g,采用随机数字表法,将其均分为五组:假手术组(S组)、心肌缺血-再灌注组(IR组)、七氟醚预处理组(SP1组)、七氟醚后处理组(SP2组)、七氟醚预处理联合后处理组(SS组).除S组外均采用结扎左冠状动脉前降支30 min,再灌注120 min的方法制备大鼠心肌缺血-再灌注模型,S组只穿线,不结扎;SP1和SP2组分别于缺血前30min、再灌注前10 min吸入2.5％七氟醚15 min,洗脱15 min;SS组于缺血前30 min和再灌注前10min均吸入2.5％七氟醚15 min,洗脱15 min.于缺血前30 min、缺血30 min、再灌注120 min时记录HR和MAP,计算RPP(SBP×HR).于再灌注120 min时取心脏制病理切片,光镜下观察各组心肌病理学变化,测定凋亡指数(AI),检测心肌组织SOD和MDA含量,免疫组化法检测心肌组织TNF-α和caspase-3的表达.结果 与S组比较,其余四组再灌注120 min时MAP和RPP明显降低,AI明显升高,心肌组织SOD含量明显降低,MDA含量明显升高,TNF-α和caspase-3表达明显增高(P＜0.05);与IR组比较,SP1组、SP2组和SS组AI明显降低,心肌组织SOD含量明显升高,MDA含量明显降低,TNF-α和caspase-3表达明显降低(P＜0.05);与SP1组和SP2组比较,SS组AI明显降低,心肌组织SOD含量明显升高,MDA含量明显降低,TNF-α和caspase-3表达明显降低(P＜0.05).结论 与单纯七氟醚预处理或后处理比较,两种方法联合应用可使心肌组织AI降低,SOD含量升高,MDA含量降低,TNF-α和caspase-3的表达降低,从而进一步减轻了大鼠心肌缺血-再灌注损伤.     

七氟醚后处理对大鼠脑缺血-再灌注损伤的抗炎作用

目的观察七氟醚后处理对大鼠脑缺血-再灌注(IR)炎症反应的作用。方法 40只Wistar大鼠被随机分为五组:S组大鼠分离血管但不阻断大脑中动脉,术后90min给予1.0MAC的七氟醚30min。IR组阻断大脑中动脉90min,在再灌注初期给予氧气30min。PS1、PS2、PS3组均阻断大脑中动脉90min,在再灌注初期分别给予0.5、1.0、1.5MAC的七氟醚30min。再灌注24h时采集股动脉血样,测定血清TNF-α、IL-10、IL-1β浓度。结果与S组比较,IR组大鼠的血清TNF-α和IL-1β浓度明显升高,而IL-10浓度明显降低(P0.05)。与IR组比较,PS1、PS2和PS3组血清TNF-α和IL-1β浓度明显降低,IL-10浓度明显升高(P0.05),并且随着七氟醚吸入浓度的增加,其作用不同程度地增强(P0.05)。结论七氟醚后处理对于缺血-再灌注大鼠可实现脑保护作用,并缓解血清炎症因子的变化。     

七氟醚预处理对急性心肌缺血再灌注损伤大鼠认知功能的影响

目的 探讨七氟醚预处理对急性心肌缺血再灌注损伤大鼠认知功能的影响.方法 健康SD大鼠60只,雌雄各半,体重300～350 g,随机分为4组:正常对照组(C组,n=6),假手术组(S组,n=18)仅挂线不结扎左冠状动脉;急性心肌缺血再灌注组(IR组,n=18)结扎左冠状动脉30 min后恢复再灌注;七氟醚预处理组(SP组,n=18)吸入七氟醚1.0 MAC 60 min,停止吸入七氟醚后60 min结扎左冠状动脉,缺血30 min后恢复再灌注.分别于左冠状动脉结扎前(T1)、缺血30 min(T2)及再灌注120 min(T3)时抽取股动脉血1 ml,测定血浆丙二醛(MDA)浓度和超氧化物歧化酶(SOD)活性.C组随机取3只大鼠,其余各组于再灌注1、3、7 d各随机取3只大鼠测定海马长时程增强(LTP),C组取另外3只大鼠,其余各组于上述时点随机取3只大鼠,测定海马肿瘤坏死因子α(TNF-α)、TNF-α mRNA、白细胞介素1β(IL-1β)、IL-1β mRNA、血红素氧合酶(HO)-1的表达水平.结果 与C组和S组比较,IR组和SP组LTP降低;与IR组比较,SP组LTP升高(P＜0.05).与C组比较,IR组和SP组HO-1、IL-1β mRNA、IL-1β、TNF-α mRNA表达上调;与S组比较,IR组和SP组IL-1β mRNA及IL-1β表达上调;与IR组比较,SP组TNF-α mRNA、HO-1、IL-1β mRNA及IL-1β表达下调,血浆MDA浓度降低,SOD活性升高(P＜0.05).结论 七氟醚预处理可改善急性心肌缺血再灌注损伤大鼠认知功能,其机制可能与下调TNF-α、IL-1β表达有关.     

七氟醚后处理对脑缺血/再灌注损伤大鼠的脑保护作用及对ROS/TXNIP/NLRP3通路的影响

目的探究七氟醚后处理对脑缺血/再灌注(ischemia/reperfusion,I/R)损伤大鼠的脑保护作用及对活性氧(reactive oxygen species,ROS)/硫氧还蛋白结合蛋白(thioredoxin interacting protein,TXNIP)/NOD样受体相关蛋白3(NOD-like receptor associated protein 3,NLRP3)信号通路的影响。方法60只SD雄性大鼠按随机数字表法分为假手术组(sham组)、I/R组、七氟醚后处理组(SP组),每组20只。采用大脑中动脉线栓法制备脑I/R模型,SP组造模后即刻吸入2.4%七氟醚30 min。对各组大鼠进行神经功能缺损评分;获取大鼠脑组织,H-E染色和2,3,5-氯化三苯基四氮唑(2,3,5-triphenyltetrazolium chloride,TTC)染色观察组织病理学变化和脑梗死体积;分析大鼠脑水肿程度及血脑屏障通透性;TUNEL法检测脑组织细胞凋亡率;检测血清炎性因子(IL-1β和IL-18)及脑组织氧化应激指标[ROS、丙二醛(malondialdehyde,MDA)、超氧化物歧化酶(superoxide dismutase,SOD)和谷胱甘肽过氧化物酶(glutathione peroxidase,GPx)]的水平;Western blot法检测TXNIP/NLRP3通路相关蛋白[TXNIP、NLRP3、凋亡相关点样蛋白(apotosis-associated speck-like protein containing a CARD,ASC)、半胱氨酸天冬氨酸酶-1(cysteine aspartase,caspase-1)]的表达。结果与sham组比较,I/R组大鼠神经功能缺损评分、脑梗死体积明显升高(P<0.05),脑组织水肿程度及血脑屏障通透性也明显增加,脑细胞凋亡率升高(P<0.05),血清IL-1β和IL-18含量明显升高(P<0.05),脑组织中ROS和MDA含量及TXNIP、NLRP3、ASC和caspase-1蛋白表达水平均明显升高(P<0.05),而GPx和SOD活性降低(P<0.05);与I/R组比较,SP组神经功能缺损评分和脑梗死体积降低(P<0.05),脑水肿程度及血脑屏障通透性下降,脑细胞的凋亡率降低(P<0.05),血清IL-1β和IL-18含量明显降低(P<0.05),脑组织中ROS和MDA含量及TXNIP、NLRP3、ASC和caspase-1蛋白水平明显降低(P<0.05),而GPx和SOD活性升高(P<0.05)。结论七氟醚后处理能够有效减轻大鼠脑I/R损伤,可能与其对ROS/TXNIP/NLRP3信号通路的抑制有关。     

舒芬太尼后处理对子宫缺血-再灌注大鼠急性肺损伤的影响

目的研究舒芬太尼后处理对子宫缺血-再灌注(IR)大鼠急性肺损伤的影响。方法成年雌性SD大鼠45只,随机分为三组:对照组(C组)、IR组和舒芬太尼后处理组(SPC组),每组15只。IR组、SPC组建立子宫缺血45 min再灌注2 h模型,SPC组给予舒芬太尼后处理。检测大鼠处理后子宫、血清及肺组织中TNF-α、丙二醛(MDA)含量、超氧化物歧化酶(SOD)活性以及肺湿干重比(W/D)、肺通透性指数(LPI)。结果 IR组、SPC组子宫、血浆及肺脏中TNF-α、MDA含量、W/D、LPI明显高于C组(P0.05);SPC组TNF-α、MDA含量、W/D、LPI明显低于IR组(P0.05);IR组、SPC组子宫、血浆以及肺脏中SOD活性明显低于C组(P0.05);SPC组SOD活性明显高于IR组(P0.05)。结论舒芬太尼后处理能减轻子宫缺血-再灌注大鼠急性肺损伤,可能与减少氧自由基和炎症因子的产生,降低肺通透性,减轻肺水肿,从而减轻子宫缺血-再灌注大鼠引发的急性肺损伤有关。     

七氟醚后处理对大鼠肠缺血再灌注损伤的影响

目的 评价七氟醚后处理对大鼠肠缺血再灌注损伤的影响.方法 成年雄性SD大鼠36只,体重200 ～ 220 g,采用随机数字表法,将其分为4组(n=9)∶假手术组(Sham组)、肠缺血再灌注组(I/R组)、缺血后处理组(Ipo组)和七氟醚后处理组(Sevo组).I/R组、Ipo组Sevo组采用结扎肠系膜上动脉60 min,再灌注120min的方法制备肠缺血再灌注模型.Ipo组于再灌注即刻恢复血流30 s后再阻断30 s,重复3次行后处理.Sevo组于再灌注即刻吸入1.15％七氟醚30 min行后处理.再灌注120 min时,处死大鼠,取小肠组织,采用Chui评分法行病理学损伤评分;采用TUNEL法计算凋亡细胞密度;采用比色法检测MDA含量和SOD活性;采用Western blot法检测caspase-3蛋白表达.结果 与Sham组相比,I/R组、Sevo组和Ipo组病理学损伤评分、凋亡细胞密度和MDA含量均升高,SOD活性降低,caspase-3蛋白表达上调(P＜0.05);与I/R组相比,Sevo组和Ipo组病理学损伤评分、凋亡细胞密度和MDA含量均降低,SOD活性升高,caspase-3蛋白表达下调(P＜0.05);Sevo组和Ipo组病理学损伤评分、凋亡细胞密度、MDA含量、SOD活性和caspase-3蛋白表达比较差异无统计学意义(P＞0.05).结论 七氟醚后处理可通过减轻脂质过氧化反应和减少细胞凋亡,减轻大鼠肠缺血再灌注损伤,其保护效应与缺血后处理相似.     

七氟醚后处理对大鼠局灶性脑缺血再灌注时氧化应激反应的影响

目的 探讨七氟醚后处理对大鼠局灶性脑缺血再灌注时氧化应激反应的影响.方法 健康雄性Wistar大鼠24只,体重240 ～ 280 g,采用随机数字表法,将大鼠随机分为3组(n=8):假手术组(S组)、局灶性脑缺血再灌注组(I/R组)和七氟醚后处理组(SP组).采用大脑中动脉阻断法制备局灶性脑缺血再灌注模型.SP组于再灌注前20 min至再灌注后10 min吸入3.9％(1.5 MAC)七氟醚.再灌注24 h时取脑组织,测定丙二醛(MDA)、谷胱甘肽(GSH)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GSH-Px)和谷胱甘肽还原酶(GR)水平,观察脑组织病理学结构;TTC染色法测定脑梗死体积.结果 与S组相比,I/R组和SP组脑梗死体积增加,MDA水平升高,I/R组GSH、SOD、CAT、GSH-Px和GR水平降低,SP组GSH-Px水平降低(P＜0.05);与I/R组相比,SP组MDA水平降低,脑梗死体积减小,GSH、SOD、CAT、GSH-Px和GR水平升高(P＜0.05).SP组脑组织病理学损伤较I/R组减轻.结论 七氟醚后处理减轻大鼠局灶性脑缺血再灌注损伤的机制与增强抗氧化酶活性,抑制氧化应激反应有关.     

七氟醚后处理对糖尿病大鼠脑缺血-再灌注损伤的影响

目的研究七氟醚后处理对糖尿病大鼠脑缺血-再灌注损伤的影响。方法雄性SD大鼠32只,3.0~3.5月龄,体重280~320 g,采用随机数字表法分为四组:非糖尿病缺血-再灌注对照组(NDC组)、糖尿病缺血-再灌注对照组(DC组)、非糖尿病缺血-再灌注七氟醚后处理组(NDS组)和糖尿病缺血-再灌注七氟醚后处理组(DS组),每组8只。采用栓线法和链脲佐霉素制备缺血-再灌注损伤大鼠模型和糖尿病大鼠模型。缺血2 h,再灌注24 h后,进行大鼠神经缺损评分,采用TTC法测定脑梗死体积,Western blot法测定血管生成素-1(angiopoiettin-1,Ang-1)蛋白含量。结果DC组神经缺损评分、脑梗死体积百分比明显高于NDC组,Ang-1蛋白含量明显低于NDC组(P0.05);NDS组神经缺损评分、脑梗死体积百分比明显低于NDC组,Ang-1蛋白含量明显高于NDC组(P0.05);DS组神经缺损评分、脑梗死体积百分比明显低于DC组,Ang-1蛋白含量明显高于DC组(P0.05)。结论大鼠脑缺血-再灌注后,糖尿病可加重神经缺损,增大脑梗死体积,减少Ang-1蛋白含量;七氟醚可减轻神经缺损,减小脑梗死体积,增加Ang-1蛋白含量;七氟醚后处理减轻大鼠脑缺血-再灌注损伤与Ang-1蛋白含量增加有关。     

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.     

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.     

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.