吸入不同浓度异氟醚对老龄大鼠海马细胞色素c表达的影响

目的 评价吸入不同浓度异氟醚对老龄大鼠海马细胞色素c(Cyt c)表达的影响.方法 健康雄性老龄SD大鼠63只,月龄20月,体重500～600 g,随机分为3组(n=21),对照组(C组):吸入30%氧气2 h;0.75%异氟醚组(L组):吸入0.75%异氟醚和30%氧气的混合气体2 h;1.5%异氟醚组(I2组):吸入1.5%异氟醚和30%氧气的混合气体2 h.分别于麻醉30 min、1和2 h时,各组取5只大鼠,取动脉血样行血气分析.于麻醉结束后24 h时,各组取8只大鼠,测定认知功能;取8只大鼠,分别采用免疫组化法和Western blot法测定海马Cyt c 的表达水平.结果 与C组比较,Ⅰ1组和Ⅰ2组逃避潜伏期延长,原平台象限停留时间缩短,穿越原平台次数减少,海马Cyt c表达上调(P＜0.05);与Ⅰ1组比较,Ⅰ2组逃避潜伏期、原平台象限停留时间缩短和穿越原平台次数差异无统计学意义(P＞0.05),海马Cyt c表达上调(P＜0.05).结论 吸入异氟醚可通过上调海马Cyt c的表达导致老龄大鼠认知功能障碍.     

异氟醚对大鼠海马蛋白激酶A和蛋白激酶C水平的影响

目的 评价异氟醚对大鼠海马蛋白激酶A(PKA)和蛋白激酶C(PKC)水平的影响.方法 健康雄性SD大鼠36只,月龄3月,体重180～220g,随机分为3组(n=12),Ⅰ组不给予任何处理,直接进行认知功能测试;Ⅱ组吸入1.2%异氟醚4 h,2 d后进行认知功能测试;Ⅲ组吸入1.2%异氟醚4 h,2周后进行认知功能测试.采用Morris水迷宫进行大鼠认知功能测试,记录逃避潜伏期.认知功能测试完毕后,处死大鼠,取海马,测定PKA和PKC的表达和活性.结果 与Ⅰ组比较,Ⅱ组逃避潜伏期差异无统计学意义(P＞0.05),Ⅲ组逃避潜伏期延长,Ⅱ组和Ⅲ组海马PKA和PKC的表达下调,活性降低(P＜0.05);与Ⅱ组比较,Ⅲ组逃避潜伏期延长(P＜0.05),海马PKA和PKC的表达和活性差异无统计学意义(P＞0.05).结论 吸入1.2%异氟醚4 h可抑制海马PKA和PKC的水平,从而导致大鼠认知功能障碍.     

手术对异氟醚麻醉下老龄大鼠术后认知功能的影响

目的 探讨手术对老龄大鼠异氟醚麻醉下术后认知功能的影响.方法 健康雄性老龄SD大鼠72只,年龄20月,体重500～600 g,随机分为3组(n=24):对照组(C组)、异氟醚麻醉组(I组)和手术组(O组).C组吸入30%氧气2 h,I组吸入1.5%异氟醚和30%氧气的混合气体2 h,O组吸入1.5%异氟醚和30%氧气的混合气体2 h,并实施腹部手术.于麻醉结束后或术后24 h时随机取8只大鼠,取海马组织,采用免疫组织化学法和RT-PCR法分别测定神经元胆碱乙酰转移酶(ChAT)及ChAT mRNA的表达水平,其余大鼠进行Morris水迷宫实验,测定认知功能.结果 与C组比较,I组和O组逃避潜伏期延长,原平台象限停留时间缩短,穿越原平台次数减少,海马神经元ChAT mRNA及其蛋白表达水平降低(P<0.05);与I组比较,O组术后第4、5天逃避潜伏期延长,原平台象限停留时间缩短,海马神经元ChAT mRNA及其蛋白表达水平降低(P<0.05);与麻醉结束后或术后第3天比较,C组第4、5天逃避潜伏期差异无统计学意义(P>0.05),I组和O组逃避潜伏期延长(P<0.05);I组和O组麻醉结束后或术后第4、5天逃避潜伏期差异无统计学意义(P>0.05).结论 手术操作可加重异氟醚引起的老龄大鼠术后认知功能障碍,其机制可能与海马胆碱能神经元受损有关.     

毒扁豆碱对异氟醚麻醉大鼠炎性反应和认知功能的影响

目的探讨毒扁豆碱对异氟醚麻醉大鼠认知功能的影响及其机制。方法 2月龄SD大鼠80只,随机分为四组,每组20只。对照组(C组)吸入含有30%氧气的空氧混合气体6h;异氟醚组(I组)吸入1.4%的异氟醚6h;毒扁豆碱+异氟醚组(PI组)与毒扁豆碱组(P组)腹腔注射毒扁豆碱100μg/kg,每8小时一次,共3次。首次给药后,PI组吸入1.4%异氟醚6h;P组吸入同浓度载气6h。麻醉结束行动脉血气分析,12h后取海马组织,ELISA法检测TNF-α、IL-1β、IL-6含量,RTPCR法检测capase-3mRNA的表达。光镜下观察海马CA1区锥体细胞形态学变化。麻醉后第2~7天评估认知功能。结果四组大鼠动脉血气指标、血糖和海马TNF-α含量差异均无统计学意义。与C组和P组比较,I组和PI组大鼠海马IL-1β、IL-6含量、capase-3mRNA明显升高,第4~6天逃避潜伏期明显延长,探索时间明显缩短(P0.05)。与I组比较,PI组大鼠海马IL-1β、IL-6含量、caspase-3mRNA表达明显降低,第4~6天逃避潜伏期明显缩短,探索时间明显延长(P0.05)。结论毒扁豆碱改善了异氟醚麻醉引起的大鼠认知功能损害,其机制可能与抑制海马炎性反应及神经元凋亡有关。     

米诺环素对异氟醚麻醉后老年大鼠认知功能和海马炎症反应的影响

目的探讨米诺环素预处理对老年大鼠吸入异氟醚后认知功能和海马炎症反应的影响。方法健康雄性SPF级SD大鼠48只,约20月龄,体重350～400g,随机分为3组:生理盐水组(NS组)、异氟醚组(Iso组)、米诺环素预给药组(M组),每组16只。NS组腹腔注射等容量生理盐水;Iso组大鼠开始吸入2.5%异氟醚3min,随后1.5%异氟醚麻醉维持4h;M组于吸入异氟醚前30min腹腔注射米诺环素50mg/kg,余同Iso组。所有大鼠麻醉结束后24h立即进行认知功能测试,包括Morris水迷宫和旷场实验测试,认知功能测试完毕后立即处死大鼠,取海马组织,采用ELISA法测定大鼠海马IL-1、IL-6、TNF-α的浓度。结果与NS组比较,Iso组第2、3和4天逃避潜伏期明显延长(P0.05),第5天平台象限停留时间明显缩短、穿越平台象限次数明显减少(P0.05),第1、2和3天中心区停留时间明显缩短(P0.05)。与Iso组比较,M组第2、3和4天逃避潜伏期明显缩短(P0.05),第5天平台象限停留时间明显延长、穿越平台象限次数明显增多(P0.05),第1、2和3天中心区停留时间明显延长(P0.05)。与NS组比较,Iso组海马IL-1、IL-6、TNF-α浓度明显升高(P0.05),与Iso组比较,M组海马IL-1、IL-6、TNF-α浓度明显降低(P0.05)。NS组和M组不同时点各指标差异无统计学意义。结论米诺环素预处理可减轻异氟醚麻醉所致老年大鼠认知功能障碍,其机制可能与抑制海马炎症反应有关。     

异氟醚对老龄和成龄大鼠海马synaptotagmin-Ⅰ蛋白质的影响

目的探讨异氟醚对成龄及老龄大鼠海马synaptotagmin-Ⅰ(Syt-Ⅰ)蛋白表达的影响。方法用蛋白质印迹方法对吸入2h异氟醚的全身麻醉模型和吸氧对照的成龄及老龄大鼠,取24h后的海马组织检测Syt-Ⅰ蛋白的表达水平。结果异氟醚麻醉后24h老龄大鼠海马组织Syt-Ⅰ蛋白质与对照组比较表达量下调(P<0.05),而成龄大鼠海马组织Syt-Ⅰ蛋白质表达量与对照组比较没有明显变化。结论异氟醚麻醉后的老龄大鼠早期海马Syt-Ⅰ蛋白质可能参与异氟醚麻醉后延迟相大鼠的学习和记忆功能改变。     

氯化锂预先给药对异氟醚麻醉诱发老龄大鼠认知功能障碍及海马炎性反应的影响

目的 评价氯化锂(LiCl)预先给药对异氟醚麻醉诱发老龄大鼠认知功能障碍及海马炎性反应的影响.方法 老龄雄性SD大鼠80只,20月龄,体重350 ～400g,采用随机数字表法,将大鼠随机分为4组(n=20):对照组(C组)吸入30％O2-70％ N26h;异氟醚麻醉组(I组)吸入1.4％异氟醚6h,以30％O2-70％N2作为载气;LiCl+异氟醚麻醉组(L+I组)腹腔注射LiC1 100 mg/kg,1次/d,连续3d,第4d行异氟醚麻醉;LiCl组(L组)腹腔注射LiCl 100 mg/kg,1次/d,连续3d,第4d吸入30％ O2-70％ N26h.麻醉结束即刻行动脉血气分析,麻醉结束后24h取海马组织,采用Western blot法测定海马糖原合成酶激酶-3β(GSK-3β)和核因子κB第310赖氨酸乙酰化蛋白[acetyl-NF-κB (Lys310)]的表达,采用实时定量PCR和ELISA法分别检测海马TNF-α、IL1β和IL-6的mRNA表达及其含量;麻醉结束后第2d评估认知功能.结果 与C组比较,I组GSK-3β和acetyl-NF-κB (Lys310)表达上调,TNF-α、IL-1β及IL-6含量及其mRNA表达水平升高,逃避潜伏期延长,探索时间缩短(P＜0.05),L+I组和L组上述指标差异无统计学意义(P＞0.05);与I组比较,L+I组GSK-3β、acetyl-NF-κB (Lys310)表达下调,TNF-α、IL-1β、IL-6含量及其mRNA表达水平降低,逃避潜伏期缩短,探索时间延长(P＜0.05).结论 氯化锂预先给药可改善异氟醚麻醉诱发老龄大鼠认知功能障碍,其机制与抑制海马炎性反应有关.     

异氟醚对老龄大鼠海马CA3区突触素表达的影响

目的 评价异氟醚对老龄大鼠海马CA3区突触素表达的影响.方法 雌性清洁级SD大鼠63只,月龄24月,体重400～650 g,随机分为3组(n=21):对照组(C组)、1.2%异氟醚组(E_1组)和1.8%异氟醚组(E_2组).C组吸入含40%氧气的空氧混合气体3 h;E_(1,2)组吸入3%异氟醚行麻醉诱导,待翻正反射消失后再分别吸入1.2%、1.8%异氟醚维持3 h.各组随机取12只大鼠,于麻醉结束后第1天采用Morris水迷宫系统测定大鼠认知功能(逃避潜伏期和探索时间),连续测定7 d;随机取9只大鼠于麻醉结束后第1、3和7天处死,测定海马CA3区突触素的表达水平.结果 与C组比较,E_1组和E_2组麻醉结束后第2、3天逃避潜伏期延长(P<0.05或0.01),第4～6天逃避潜伏期差异无统计学意义(P>0.05),麻醉结束后海马CA3区突触素表达持续下调(P<0.05).三组探索时间比较差异无统计学意义(P>0.05);与E_1组比较,E_2组逃避潜伏期差异无统计学意义(P>0.05),海马CA3区突触素表达下调(P<0.01).结论 异氟醚致老龄大鼠认知功能障碍与海马突触素表达无关.     

褪黑素对异氟醚麻醉大鼠海马胆碱乙酰基转移酶的影响

目的 探讨褪黑素对异氟醚麻醉大鼠海马胆碱乙酰基转移酶(ChAT)的影响.方法雄性SD大鼠60只,体重390～440 g,采用随机数字表法,将大鼠随机分为5组(n=12):对照组(C组)、1%异氟醚组(Ⅰ组)、1%异氟醚+褪黑素组(IM组)、2%异氟醚组(J组)和2%异氟醚+褪黑素组(JM组).IM组和JM组腹腔注射褪黑素10 mg/kg,1次/d,连续7 d,C组、Ⅰ组和J组给予等容量生理盐水.Ⅰ组、IM组第7天吸入1%异氟醚4 h,J组、JM组第7天吸入2%异氟醚4 h.于麻醉次日行Morris水迷宫实验,测试逃避潜伏期及原平台象限探索时间;水迷宫实验结束后取血浆及脑组织,采用ELISA法测定血浆褪黑素浓度,Western blot法测定海马ChAT表达水平,采用比色法测定海马ChAT活性,采用免疫荧光法测定海马CA1区和齿状回的ChAT阳性神经元数量.结果 与C组比较,Ⅰ组血浆褪黑素浓度、ChAT表达水平和活性降低(P＜0.01);J组逃避潜伏期延长,原平台象限探索时间缩短,血浆褪黑素浓度、ChAT表达水平和活性降低(P＜0.05或0.01).与Ⅰ组比较,IM组逃避潜伏期缩短,原平台象限探索时间延长,褪黑素浓度升高,ChAT表达水平和活性升高(P＜0.05或0.01).与J组比较,JM组逃避潜伏期缩短,褪黑素浓度升高,ChAT活性升高(P＜0.05或0.01).海马CA1区和齿状回的ChAT阳性神经元数量与ChAT表达水平变化一致.结论 褪黑素可减轻异氟醚麻醉对ChAT表达水平及活性的抑制,从而改善异氟醚麻醉后大鼠的认知功能.

Abstract：

Objective To investigate the effects of melatonin on choline acetyltransferase (ChAT) in rat hippocampus after isoflurane anesthesia. Methods Sixty male SD rats weighing 390 - 440 g were randomized into 5 groups (n = 12 each): control group (group C), 1% isoflurane group (group Ⅰ), 1% isoflurane + melatonin group (group IM) , 2% isoflurane group (group J) and 2% isoflurane + melatonin group (group JM) . In IM and JM groups, melatonin 10 mg/kg was administered intraperitoneally once a day for 7 consecutive days, while equal volume of normal saline was given intraperitoneally instead of melatonin in C, I and J groups. Groups Ⅰ and IM inhaled 1% isoflurane and groups J and JM 2% isoflurane for 4 h on 7th day. All the rats underwent Morris water maze test on the day after anesthesia for assessment of learning and memory ability (escape latency and probe time) . The training test was performed 4 times a day for S days. Six rats randomly selected from each group were sacrificed the end of the test. The blood samples were collected for detection of plasma melatonin level by ELISA.The brain tissues were removed for determination of the expression and activity of ChAT in hippocampus by Western blot or colorimetric assay. The left rats were selected and sacrificed for determination of the number of ChAT positive neurons in hippocampal CA1 region and entate gyrus by immunofluorescence. Results The plasma melatonin level and expression and activity of ChAT were significantly lower in group I than in group C ( P ＜ 0.01) . The escape latency was significantly longer, the probe time was significantly shorter, and the plasma melatonin level and expression and activity of ChAT were significantly lower in group J than in group C ( P ＜ 0.05 or 0.01) . The escape latency was significantly shorter, the probe time was significantly longer, and the plasma melatonin level and expression and activity of ChAT were significantly higher in group IM than in group Ⅰ ( P ＜ 0.05 or 0.01). The escape latency was significantly shorter and the plasma melatonin level and ChAT activity were significantly higher in group JM than in group J ( P ＜ 0.05 or 0.01) . The results of immunofluorescent staining showed that the number of ChAT positive neurons in hippocampal CA1 region and dentate gyrus wag consistent with the changes in the measured ChAT expression. Conclusion Melatonin can reduce isoflurane-mediated inhibition of ChAT expression and activity and thus improve spatial memory impaired by isoflurane anesthesia in rats.     

孕早期异氟醚麻醉对子代大鼠认知功能的影响

目的 评价孕早期异氟醚麻醉对子代大鼠认知功能的影响.方法 孕5～7d的SD大鼠30只,采用随机数字表法,将其随机分为3组(n=10):正常对照组(C组)、吸入异氟醚4h组(Ⅰ1组)和吸入异氟醚8h组(Ⅰ2组).Ⅰ1组和Ⅰ2组分别吸入95％氧气-1.4％异氟醚4h和8h,氧流量2L/min,C组吸入95％氧气8h.分别于出生后20、30 d取5只母鼠的子鼠,采用Morris水迷宫实验测定认知功能,持续7d,然后处死子代大鼠,分离海马组织,测定N-甲基-D-天冬氨酸受体2B亚基mRNA及其蛋白的表达水平.结果 3组子代大鼠水迷宫实验结果、N-甲基-D-天冬氨酸受体2B亚基mRNA及其蛋白表达水平差异均无统计学意义(P＞0.05).结论 孕早期异氟醚麻醉对子代大鼠认知功能无影响.     

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.     

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.