右美托咪啶后处理对大鼠离体心脏缺血再灌注时线粒体损伤的影响

目的 探讨右美托咪啶后处理对大鼠离体心脏缺血再灌注时线粒体损伤的影响.方法 健康雌性Wistar大鼠,体重220～250 g,成功制备Langendorff离体灌注模型的40个心脏随机分为5组(n=8):缺血再灌注组(A组)、右美托咪啶10 nmol/L组(B组)、右美托咪啶100 nmol/L组(C组)、线粒体通透性转换孔开放剂苍术苷组(D组)及右美托咪啶联合苍术苷组(E组).离体心脏经K-H液平衡灌注20 min后,采用全心停灌40 min再灌注60 min的方法制备离体心脏缺血再灌注模型.于再灌注即刻B组、C组、D组和E组分别灌注含10 nmol/L右美托咪啶、100 nmol/L右美托咪啶、20μmol/L苍术苷、100 nmol/L右美托咪啶和20 μmol/L苍术苷的K-H液10 min.再灌注结束即刻取心尖组织,分离线粒体,测定SOD、Na+ -K+ -ATP酶、Ca2+-ATP酶活性和MDA和Ca2+含量.结果 与A组比较,B组和C组线粒体SOD、Na+ -K+ -ATP酶和Ca2+ -ATP酶活性升高,MDA和Ca2+含量降低(P＜0.05),D组和E组上述指标比较差异无统计学意义(P＞0.05);与C组比较,D组和E组线粒体SOD、Na+-K+-ATP酶和Ca2+ -ATP酶活性降低,MDA和Ca2+含量升高(P＜0.05),B组上述指标比较差异无统计学意义(P＞0.05).结论 右美托咪啶后处理可减轻大鼠离体心脏缺血再灌注时的线粒体损伤,其机制可能与抑制线粒体通透性转换孔开放有关.     

缺血后处理减轻犬肾缺血再灌注损伤的作用

目的 探讨缺血后处理减轻犬肾缺血再灌注损伤的作用及其相关机制.方法 随机将犬分为假手术组、缺血再灌注组和缺血后处理组,每组5只.假手术组:犬麻醉后,取其腹正中切口进入腹腔,游离双侧肾脏,切除右肾后,关腹.缺血再灌注组:手术操作与假手术组相同,仅在切除右肾和游离左肾之后,将左肾动、静脉夹闭60 min,然后开放血管.缺血后处理组:手术操作与缺血再灌注组相同,仅在肾动、静脉被夹闭60 min后,以再灌注(开放血管)30 s、夹闭血管30 s为1个循环,共进行6次循环,然后完全放开血管.分别于术后24、48及72 h采集犬静脉血2 ml,使用全自动生化分析仪测定各组犬血清肌酐(Cr)和尿素氮(BIJN)水平;术后第3天取犬肾组织,采用硫代巴比妥酸法测定丙二醛(MDA)含量,采用黄嘌呤氧化酶法测定超氧化物歧化酶(SOD)活性,采用化学比色法测定髓过氧化物酶(MPO)活性,并观察犬肾组织的病理改变和细胞凋亡情况.结果 术后各时间点,缺血再灌注组、缺血后处理组和假手术组犬的血清Cr和BUN水平均依次降低,3组间比较,差异均有统计学意义(P<0.05).术后第3天,缺血再灌注组、缺血后处理组和假手术组犬肾组织中SOD活性依次升高,而MDA含量和MPO活性均依次降低,3组间比较,差异均有统计学意义(P<0.05).假手术组肾小球和肾小管结构正常,未见明显病理改变;缺血再灌注组肾间质水肿,大量炎症细胞浸润,肾小管上皮细胞刷状缘消失,大量上皮细胞坏死、脱落,管腔扩张,其中可见大量管型;缺血后处理组可见肾间质轻度水肿,肾小管上皮细胞扁平,部分刷状缘消失、坏死,偶见管型,管周血管有少量淤血.假手术组、缺血再灌注组、缺血后处理组犬肾的细胞凋亡指数分别为2.7±1.3、28.4±6.2和15.4±4.1,3组间比较,差异均有统计学意义(P<0.05).结论 缺血后处理能减轻犬肾缺血再灌注损伤,其机制可能与缺血后处理减少氧自由基的产生、抑制细胞凋亡及减少炎症细胞浸润有关.     

右美托咪啶对大鼠全脑缺血再灌注损伤的影响

目的 评价右美托咪啶对大鼠全脑缺血再灌注损伤的影响.方法 健康雄性SD大鼠54只,体重200 ～ 250 g,采用随机数字表法,将其随机分为3组(n=18):假手术组(S组)、缺血再灌注组(I/R组)和右美托咪啶组(D组).I/R组和D组采用夹闭双侧颈总动脉联合低血压法建立大鼠全脑缺血再灌注损伤模型.D组于缺血再灌注即刻静脉注射右美托咪啶3 μg/kg,后以3μg·kg-·h-1的速率静脉输注至再灌注2h.于再灌注6 h(T1)、24 h(T2)和72 h(T3)时行神经功能缺陷评分(NDS评分),然后各组随机处死6只大鼠,取脑组织,观察海马CA1区病理学结果,采用分光光度计法测定髓过氧化物酶(MPO)活性,采用ELISA法测定TNF-α、IL-1β的含量,采用免疫组化法测定胶质纤维酸性蛋白(GFAP)表达.结果 与S组比较,I/R组和D组T1 ～3时NDS评分、脑组织MPO活性、TNF-α和IL-1β的含量升高,T2,3时GFAP表达上调(P＜0.05或0.01),海马CA1区病理学损伤明显;与I/R组比较,D组T1 ～3时NDS评分、脑组织MPO活性和TNF-α含量降低,T1,2时脑组织IL-1β含量降低,T2,3时脑组织GFAP表达下调(P＜0.05或0.01),海马CA1区病理学损伤减轻.结论 右美托咪啶可减轻大鼠全脑缺血再灌注损伤,其机制可能与抑制炎性反应有关.     

右美托咪啶预处理对大鼠离体心脏缺血再灌注损伤的影响

目的 评价右美托咪啶预处理对大鼠离体心脏缺血再灌注损伤的影响.方法 健康清洁级雄性Wistar大鼠24只,体重230～ 260 g,制备离体Langendorff心脏灌注模型后,采用随机数字表法,将离体心脏随机分为3组(n=8):缺血再灌注组(I/R组)、右美托咪啶Ⅰ组(DI组)、右美托咪啶Ⅱ组(DⅡ组).各组均先用K-H液平衡灌注10 min后,I/R组用K-H液继续灌注30 min,D I组和DⅡ组分别用含有0.23.、2.30ng/ml右美托咪啶的K-H液继续灌注20 min,再用K-H液冲洗10 min.各组心脏均缺血30 min,K-H液再灌注120 min.于平衡灌注末、再灌注5、30、60和120min时收集冠脉流出液,测定肌酸激酶(CK)和乳酸脱氢酶(LDH)活性.再灌注末取心肌组织,测定SOD活性及MDA含量.结果 与I/R组比较DⅠ组和DⅡ组冠脉流出液CK、LDH活性、心肌组织MDA含量降低,心肌组织SOD活性升高(P＜0.05);与DI组比较,DⅡ组冠脉流出液CK、LDH活性、心肌组织MDA含量降低,心肌组织SOD活性升高(P＜0.05).结论 右美托咪啶预处理可减轻大鼠心肌缺血再灌注损伤,且与浓度有关.     

右美托咪啶预先给药对大鼠局灶性脑缺血再灌注损伤的影响

目的 评价右美托咪啶预先给药对大鼠局灶性脑缺血再灌注损伤的影响.方法 健康雄性SD大鼠100只,体重290～310 g,采用随机数字表法,将其随机分为5组(n=20):假手术组(SH组)、缺血再灌注组(I/R组)和不同剂量右美托咪啶预先给药组(L组、M组和H组).I/R组、L组、M组和H组采用线栓法建立大鼠局灶性脑缺血再灌注损伤模型,缺血60 min后行再灌注.L组、M组和H组于缺血前15 min分别腹腔注射右美托咪啶100、200和400 μg/kg,I/R组腹腔注射等容量生理盐水.再灌注24h时,随机取10只大鼠,测定神经功能缺陷评分和脑梗死体积,观察脑组织病理学改变;随机取10只大鼠,测定缺血侧脑组织热休克蛋白70(HSP70)表达、Na+ -K+ -ATP酶活性和血浆SOD活性、皮质醇浓度.结果 与SH组比较,I/R组、L组、M组和H组神经功能缺陷评分和皮质醇浓度升高,SOD和Na+ -K+ -ATP酶的活性降低,HSP70表达上调(P＜0.05);与I/R组比较,L组、M组和H组神经功能缺陷评分、脑梗死体积和皮质醇浓度降低,HSP70表达上调,SOD和Na+ -K+ -ATP酶的活性升高,且呈剂量依赖性(P＜0.05),病理学损伤程度呈剂量依赖性减轻.结论 右美托咪啶预先给药可减轻大鼠局灶性脑缺血再灌注损伤,且呈剂量依赖性,其机制可能与改善脑细胞能量代谢、减轻脂质过氧化反应和应激反应有关.     

右美托咪啶复合舒芬太尼预处理对大鼠离体心脏缺血再灌注损伤的影响

目的 探讨右美托咪啶复合舒芬太尼预处理对大鼠离体心脏缺血再灌注损伤的影响.方法 雄性SD大鼠,8～ 10周龄,体重180 ～ 220 g,采用Langendorff装置建立大鼠离体心脏灌注模型.取离体灌注的心脏40个,采用随机数字表法,将心脏随机分为5组(n=8):正常对照组(C组):用K-H液持续灌注180 min;缺血再灌注组(I/R组):停止灌注K-H液30 min再灌注120 min;右美托咪啶预处理组(DP组):缺血前30 min用含右美托咪啶2.3 ng/ml的K-H液灌注30 min;舒芬太尼预处理组(SP组):缺血前30 min用含舒芬太尼3.77 ng/ml的K-H液灌注30 min;右美托咪啶预处理+舒芬太尼预处理组(DS组):缺血前30 min用含有右美托咪啶2.3 ng/ml和舒芬太尼3.77 ng/ml的K-H液灌注30min.于心脏稳定灌注15 min、缺血前即刻、缺血30 min、再灌注120 min时收集冠状动脉流出液,测定冠状动脉流出量(CF),记录左心室发展压(LVDP)、左心室内压最大上升/下降速率(±dp/dtmax)和心率(HR);再灌注120min时测定心肌超氧化物歧化酶(SOD)和髓过氧化物酶(MPO)活性、丙二醛(MDA)含量和心肌梗死面积.结果 与C组比较,其余各组CF、LVDP、±dp/dtmax、HR和心肌SOD活性降低,心肌梗死面积、心肌MDA含量和MPO活性升高(P＜0.05);与I/R组比较,DP组和DS组CF降低,SP组和DS组HR降低,DP组、SP组和DS组LVDP、±dp/dtmax和心肌SOD活性升高,MDA含量和MPO活性降低,心肌梗死面积减小(P＜0.05);与DS组比较,DP组CF降低,HR升高,SP组CF增高、心肌SOD活性降低,MDA含量和MPO活性升高,心肌梗死面积增加(P＜0.05),DP组心肌SOD和MPO活性、MDA含量和心肌梗死面积差异无统计学意义(P＞0.05).结论 右美托咪啶复合舒芬太尼预处理可减轻大鼠离体心脏缺血再灌注损伤,但复合应用效果并未进一步增强.     

缺血后处理对肾缺血再灌注损伤的抑制作用及对细胞凋亡的影响

目的 观察缺血后处理对大鼠急性.肾缺血再灌注损伤的抑制作用及其对细胞凋亡的影响.方法 建立原位大鼠单侧肾缺血再灌注动物模型,摘除右肾后对左肾行缺血后处理,即10 s再灌注,10 s缺血,6次循环后再灌注24 h.全自动生化分析仪检测血尿素氮(BUN)和肌酐(Cr)含量,比色法测定血浆中脂质过氧化产物丙二醛(MDA)和超氧化物歧化酶(SOD)含量,免疫组织化学法观察肾组织中细胞色素C的表达,流式细胞术检测细胞凋亡率,免疫印迹法(Western blot)检测胞浆中细胞色素C的含量.结果 肾缺血再灌注24 h后,血中BUN、Cr和MDA明显增高,肾细胞凋亡率明显增加.移植肾经缺血后处理,血中BUN、Cr和MDA含量均降低,SOD含量升高,细胞色素C释放减少,肾细胞凋亡率明显降低.结论 缺血后处理可以减轻移植肾脂质过氧化反应,减少肾细胞凋亡率,减轻肾缺血再灌注损伤.     

肢体缺血后处理和肾脏缺血后处理对大鼠肾脏缺血-再灌注损伤的影响

目的 探讨肢体缺血后处理和肾脏缺血后处理对大鼠肾脏缺血-再灌注(I-R)损伤的影响.方法 24只大鼠随机均分为假手术组(S组)、缺血-再灌注组(I-R组)、左下肢缺血后处理组(LIP组)及肾脏缺血后处理组(RIP组).S组仅对左肾动脉进行游离;I-R组:夹闭左肾动脉45 min后松开,左肾再灌注6 h;LIP组在左肾复灌前6 min时左股动脉夹闭5 min;RIP组在左肾缺血45min后灌注10 s,停灌10 s,反复6次;检测复灌6 h时血清肌酐(Cr)、血尿素氮(BUN);光镜下观察肾组织病理改变,TUNEL法检测肾组织中凋亡细胞并计算凋亡指数(AI);免疫组化法检测肾组织Fas、Caspase-3表达;电镜下观察肾单位超微结构改变.结果 与S组比较,其他三组大鼠BUN、Cr浓度升高(P<0.01)、肾组织病理改变明显、肾组织Fas、Caspase-3阳性指数和AI增加(P<0.01).与I-R组比较,LIP、RIP组大鼠BUN、Cr浓度降低(P<0.01),肾组织Fas、Caspase-3阳性指数和AI降低(P<0.01).RIP组AI明显低于LIP组(P<0.05).结论 在肾脏I-R损伤的病理过程中,肾小管上皮细胞凋亡可以由胞膜上的Fas被激活而最终导致靶细胞凋亡;两种后处理都可以抑制肾小管上皮细胞凋亡,减轻I-R损伤.     

右美托咪定减轻肾缺血?再灌注损伤中肾小球内皮糖萼的破坏

目的观察右美托咪定对肾缺血-再灌注损伤(kidney ischemia-reperfusion injury,KIRI)中肾小球内皮糖萼的影响。方法成年雄性SD大鼠28只,随机分为四组:假手术组(S组)、假手术+右美托咪定组(SD组)、肾缺血-再灌注组(R组)和肾缺血-再灌注+右美托咪定组(RD组),每组7只。术前30 min SD组和RD组腹腔注射右美托咪定25μg/kg,S组和R组注射等体积生理盐水。S组和SD组进行假手术,R组和RD组建立缺血45 min再灌注24 h急性肾损伤模型。24 h后分别检测血肌酐(Scr)、血尿素氮(BUN)浓度及观察肾组织的病理学变化。电镜和共聚焦显微镜下观察肾小球内皮糖萼的结构变化。采用Western blot法测定肾组织多配体聚糖1(Syndecan-1)、乙酰肝素酶1(Heparanase-1)、血管生成素受体2(Tie2)蛋白含量。结果与S组比较,R组Scr和BUN浓度明显升高(P0.05),肾组织病理性损伤明显加重,电镜和共聚焦显微镜下肾小球内皮糖萼结构明显破坏,肾组织Syndecan-1、Tie2蛋白含量明显降低(P0.05),Heparanase-1蛋白含量明显升高(P0.05)。与R组比较,RD组Scr和BUN浓度明显降低(P0.05),肾组织病理性损伤明显减轻,电镜和共聚焦显微镜下肾小球内皮糖萼结构破坏明显减轻,肾组织Syndecan-1、Tie2蛋白含量明显升高(P0.05),Heparanase-1蛋白含量明显降低(P0.05)。结论右美托咪定可能通过保护和重建肾小球内皮糖萼减轻KIRI,其机制可能与抑制Heparanase-1以及激活Tie2受体有关。     

缺血后处理对大鼠肾缺血再灌注损伤的影响

目的探讨缺血后处理对大鼠肾缺血再灌注（I／R）损伤的影响及其机制。方法18只雄性SD大鼠随机分为3组（n=6）：假手术组（S组）、缺血再灌注组（I／R组）和缺血后处理组（IPo组）。采用夹闭双侧肾蒂45min-再灌注6h制备肾脏缺血再灌注损伤模型。IPo组在夹闭双侧肾蒂45min后，再灌注10s，缺血10s，重复3次后，完全恢复肾血流。再灌注6h时开胸，取心脏血后处死大鼠，取肾组织。测定血清肌酐（Cr）、尿素氮（BUN）和尿酸（UA）浓度，肾组织中丙二醛（MDA）含量和超氧化物歧化酶（SOD）活性；光镜下观察肾组织病理学改变；采用原位末端脱氧核苷酸转移酶标记（TUNEL）法检测肾组织中凋亡细胞，光镜下计数凋亡细胞，并计算肾小管上皮细胞凋亡指数（AI）。结果与S组比较，I／R组和IPo组Cr和BUN浓度升高（P〈0．05），UA浓度差异无统计学意义（P〉0．05），肾组织SOD活性降低，MDA含量升高，肾小管上皮细胞凋亡指数增加（P〈0．05），病理损伤明显。与I／R组比较，IPo组Cr和BUN浓度降低（P〈0．05），UA浓度差异无统计学意义（P〉0．05），SOD活性升高，MDA含量降低，肾小管上皮细胞凋亡指数减少（P〈0．05），病理损伤减轻。结论缺血后处理能减轻大鼠肾缺血再灌注损伤，其机制与增强肾脏抗氧化能力和抑制肾组织细胞凋亡有关。     

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.     

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.     

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.     

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.