二氮嗪预处理抑制大鼠肝缺血再灌注所致细胞凋亡的延迟保护作用

目的：探讨二氮嗪(DE)预处理模拟缺血预处理(IP)抑制肝缺血再灌注(I/R)损伤所致细胞凋亡的延迟保护(DP)作用及其可能机制。方法：大鼠随机分为5组:IP组以肝缺血5min作I/R预处理;DE组静脉注射DE 作I/R预处理;DE+5-HD组在DE组基础上再予静脉注射5-HD作预处理;对照组(C组)仅以等量生理盐水作预处理;假手术组（S组）仅行2次开腹手术，不作其他处理。4个预处理组均在24h后行肝缺血1h再灌注3h。切取肝组织用免疫组化法检测Bcl-2蛋白表达及用TUNEL法检测肝细胞凋亡,并观察显微结构变化。结果： C组肝细胞凋亡指数(AI)明显高于S组(P<0.01),光镜与电镜下肝脏结构损伤明显;IP组与DE组Bcl-2蛋白表达指数(BI)高于C组(P<0.01),AI明显低于C组(P<0.05),组织损伤也轻于C组;而DE+5-HD组BI低于DE组(P<0.01),AI则高于DE组(P<0.05)。结论：使用DE预处理能模拟IP抗大鼠I/R损伤所致肝细胞凋亡的DP作用,可能系通过诱导肝细胞Bcl-2蛋白表达上调而发挥抗凋亡作用。     

七氟烷预处理对局灶性脑缺血再灌注损伤大鼠线粒体通透性转换孔的影响

目的 探讨七氟烷预处理对局灶性脑缺血再灌注损伤大鼠线粒体通透性转换孔(mPTP)的影响.方法 成年雄性SD大鼠60只,体重250～300 g,随机分为5组(n=12):假手术组(S组)、缺血再灌注组(I/R组)、七氟烷预处理组(Sev组)、线粒体ATP敏感性钾离子通道(mito-KATP通道)阻断剂5-羟癸酸(5-HD)+Sev组和5-HD组.采用大脑中动脉阻断法制备局灶性脑缺血再灌注模型.S组只分离血管不置入线栓;I/R组制备局灶性脑缺血再灌注模型;Sev组吸入2.4%七氟烷60 min行预处理,24 h后制备局灶性脑缺血再灌注模型;5-HD+Sev组腹腔注射5-HD 40mg/kg,30 min后行七氟醚预处理,其余处理同Sev组;5-HD组腹腔注射5-HD 40 mg/kg,30 min后制备局灶性脑缺血再灌注模型.于再灌注24 h时断头取缺血侧顶叶皮层组织,测定mPTP活性,Western blot法测定Bcl-2、Bax表达水平,并计算Bcl-2/Bax比值,采用TUNEL法检测神经元凋亡情况.结果 与S组比较,I/R组、Sev组、5-HD+Sev组和5-HD组凋亡神经元计数升高,Bcl-2和Bax表达上调,Bcl-2/Bax比值升高,mPTP活性升高(P＜0.05);与I/R组比较,Sev组凋亡神经元计数减少,Bcl-2表达上调,Bcl-2/Bax比值升高,mPTP活性降低(P＜0.05);与Sev组比较,5-HD+Sev组和5-HD组Bcl-2表达下凋,Bcl-2/Bax比值降低,mPTP活性升高(P＜0.05);5-HD+Sev组与5-HD组上述指标比较差异无统计学意义(P＞0.05).结论 七氟烷预处理可能通过激活神经元mito-KATP通道,上调Bcl-2的表达,从而抑制mPTP的大量开放减轻大鼠局灶性脑缺血再灌注时的神经元凋亡.     

异氟醚预处理对沙士鼠脑缺血再灌注损伤的保护作用

目的探讨异氟醚预处理对沙士鼠脑缺血再灌注损伤的保护作用及可能的机制。方法75只雄性沙士鼠，随机分5组，每组15只。假手术组（SHAM组）；I／R组：夹闭双侧颈总动脉5min后开放造成缺血再灌注；异氟醚预处理组（ISO组）：缺血前60min吸入1．2％．1．5％异氟醚30min；5．羟葵酸盐组（5-HD组）：缺血前30min腹腔内注射线粒体ATP敏感性钾通道抑制剂5-HD 10mg／kg；5．HD＋ISO组：腹腔内注射5-HD10mg／kg，30min后同ISO组。再灌注24h，取鼠前脑，透射电镜下观察线粒体超微结构，用荧光分光光度计测定线粒体游离Ca^2＋浓度，用紫外分光光度计测定线粒体通透转运通道（MPTP）开放程度。结果I／R组、5-HD和5-HD＋ISO组线粒体肿胀，嵴断裂、溶解，内呈空泡状，ISO和SHAM组线粒体结构较完整，嵴及内膜间隙仍清晰可见。I／R、5．HD、5．HD＋ISO组线粒体游离Ca^2＋浓度及MFrP开放程度均高于SHAM组，ISO组线粒体游离Ca^2＋浓度及MPTP开放程度低于I/R组（P〈0．05）。结论异氟醚预处理对沙士鼠脑缺血再灌注损伤有保护作用，可能是通过激活线粒体ATP敏感性钾通道，减轻Ca^2＋超载，从而抑制MPTP开放而产生的。     

二氮嗪后处理对大鼠离体心脏缺血再灌注损伤的影响

目的 评价二氮嗪后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,体重250～300 g,成功建立Langendorff再灌注模型的64个心脏随机分为4组(n=16):正常对照组(C组)、缺血再灌注组(I/R组)、二氮嗪后处理组(D组)和线粒体ATP敏感性钾通道阻断剂5-羟葵酸+二氮嗪后处理组(5-HD+D组).采用K-H液平衡灌注20 min时,C组继续灌注K-H液70 min;I/R组、D组和5-HD+D组进行心肌缺血40 min,I/R组缺血前灌注4 ℃ ST.Thomas停跳液10 ml/kg;D组再灌注5 min时灌注含50μmol/L二氮嗪的K-H液5 min,然后再灌注20 min;5-HD+D组灌注二氮嗪前灌注含100 μmol/L 5-羟葵酸的K-H液5 min,再灌注20 min.分别于平衡灌注末与再灌注末时取8个心脏,记录心功能指标,然后提取线粒体,测定心肌细胞线粒体膜电位(MMP)、氧自由基(ROS)生成量和呼吸功能指标.结果 各组平衡灌注末时各指标差异无统计学意义(P＞0.05).与C组比较,再灌注末时其余3组心功能和线粒体呼吸功能减退,MMP降低,ROS生成量增加(P＜0.05或0.01);与I/R组和5-HD+D组比较,D组心功能和线粒体呼吸功能改善,MMP升高,ROS水平降低(P＜0.01).结论二氮嗪后处理可减轻大鼠心肌缺血再灌注损伤,其机制与开放线粒体ATP敏感性钾通道而改善线粒体功能有关.     

缺血预处理对大鼠离体缺血再灌注心脏心肌功能和线粒体ATP敏感性钾通道的影响

目的研究缺血预处理(IP)对大鼠离体心脏缺血再灌注损伤的保护作用机制。方法 Wistar大鼠48只,其中40只随机分为缺血再灌注组(I/R组)、IP组、二氮嗪组(DZ组)、5-羟葵酸(选择性线粒体ATP敏感性钾通道阻滞剂)拮抗IP组(5-HD IP组)、5-羟葵酸拮抗二氮嗪组(5-HD DZ 组),每组8只,另外8只用作正常心肌线粒体电镜检查对照组。应用Langendorff离体心脏灌注系统建立心脏缺血再灌注模型,平衡灌注20 min后,30 min预处理期间各组进行以下处理,IP组进行2次缺血再灌注,灌注压8．5 kPa,灌注速率8．5 ml／min。每次IP缺血5 min再灌注5 min;DZ组灌注50 μmol ·L-1二氮嗪;5-HD IP组灌注100 μmol·L-1 5-羟葵酸10 min,然后给予2次IP;5-HD DZ组灌注5-羟葵酸100μmol-L-1 10min,再灌注二氮嗪50μmol·L-1 10min。然后各组全心缺血40min,再灌注30min。持续测定心功能指标[心率、左心室发展压(INDP)、左心室舒张末压(INEDP)和冠脉流量(CF)],再灌注末取心肌,提取线粒体,电镜下观察其病理学改变,并进行线粒体Flameng评分。结果与I／R组比较,IP和二氮嗪预处理能明显提高再灌注期间LVDP,降低LVEDP,降低心肌线粒体Flameng评分(P< 0．01),减轻心肌病理学损伤;5-羟葵酸能部分拮抗IP、完全拮抗二氮嗪预处理对心肌缺血再灌注损伤的保护作用。结论 IP对心肌缺血再灌注损伤的保护作用与线粒体ATP敏感性钾通道的激活有关。     

ATP敏感性钾通道在硫化氢减轻大鼠肝缺血再灌注损伤中的作用

目的 评价ATP敏感性钾(KATP)通道在硫化氢减轻大鼠肝缺血再灌注损伤中的作用.方法 健康雄性SD大鼠30只,体重220～250 g,采用阻断左叶和中叶肝脏血流的方法制备肝缺血再灌注损伤模型.采用随机数字表法,将大鼠随机分为5组(n=6):假手术组(S组)仅开腹分离肝蒂,不进行肝门阻断及再灌注;缺血再灌注组(I/R组)制备肝缺血再灌注模型;硫氢化钠组(NaHS组)于再灌注前5 min时腹腔注射NaHS 28 μmol/kg,余同I/R组;格列本脲组(G组)于NaHS给药前5 min时腹腔注射非选择性KATP通道阻断剂格列本脲6 mg/kg,余同NaHS组;5-羟基葵酸组(5-HD组)于NaHS给药前5 min时腹腔注射选择性KATP通道阻断剂5-HD 10 mg/kg,余同NaHS组.于再灌注6h时,采集下腔静脉血样,测定血清ALT和AST的活性;然后处死大鼠,取肝组织,测定TNF-α含量和MPO活性,并观察病理学结果.结果 与S组比较,I/R组、NaHS组、G组和5-HD组血清ALT和AST活性升高,I/R组、G组和5-HD组肝组织TNF-α含量和MPO活性升高,NaHS组肝组织TNF-α含量升高(P＜0.01);与I/R组比较,NaHS组血清ALT、AST活性和肝组织TNF-α含量、MPO活性降低(P＜0.01),病理学损伤减轻;与NaHS组比较,G组和5-HD组血清ALT、AST活性和肝组织TNF-α含量、MPO活性升高(P＜0.01).结论 KATP通道的开放参与了硫化氢减轻大鼠肝缺血再灌注损伤.     

二氮嗪预处理对未成熟兔心脏的保护作用

目的 了解二氮嗪预处理对未成熟兔心脏有无保护作用,并探讨其机制。方法 大耳白幼兔(小于28 d)21只随机分成三组:对照组(Ⅰ组n=8):K-H缓冲液灌注30 min后St.ThomasⅡ号停跳液(STH)停跳;二氮嗪预处理组(Ⅱ组n=8):二氮嗪(100μmol/L)灌注5 min,再K-H液灌注10min后STH停跳;二氮嗪+5-HD组(Ⅲ组n=5):二氮嗪和5-HD(均100μmol/L)共同灌注5 min后停跳。在LangendOrff模型上进行离体心脏常温缺血/再灌注(I/R)实验。观察再灌后血液动力学恢复、冠脉流出液心肌酶、心肌组织内ATP含量及心肌超微结构变化。结果 再灌后Ⅱ组左室发展压(LVDP)、左室压力上升和下降最大速率(±dp/dtmax)的恢复率在多个时间点上均高于Ⅰ组,再灌末心肌组织ATP含量也高于Ⅰ组(P<0.01),冠脉流出液中的三种心肌酶值均较Ⅰ组降低(P<0.01)。Ⅱ组的线粒体评分低于Ⅰ组(P<0.01),Ⅲ组线粒体评分回到Ⅰ组水平(P>0.05)。结论 二氮嗪能通过开放线粒体ATP敏感性通道而发挥对幼兔心肌的保护作用。     

线粒体心磷脂在二氮嗪预处理减轻大鼠离体心脏缺血再灌注损伤中的作用

目的 评价线粒体心磷脂在二氮嗪预处理减轻大鼠离体心脏缺血再灌注损伤中的作用.方法 清洁级SD大鼠72只,体重200～280 g,雌雄各半,随机分为对照组(C组)、缺血再灌注组(I/R组)、二氮嗪预处理组(DZ组)和5-羟葵酸拮抗二氮嗪组(HD组),每组18只.采用Langendorff灌流装置建立大鼠离体心脏缺血再灌注模型,C组平衡灌注20 min,持续灌注100 min;I/R组平衡灌注20 min,持续灌注30 min,缺血40 min,再灌注30 min;DZ组平衡灌注20 min后,依次灌注K-H液15 min、50 μmol/L二氮嗪10 min和K-H液5 min,其余缺血再灌注同I/R组;HD组二氮嗪预处理前给予含5-羟葵酸100 μmol/L K-H液10 min,其余处理同DZ组.各组分别于平衡灌注末(T1)、缺血前即刻(T2)、再灌注末(T3)时随机取6只大鼠,监测心率(HR)、左心室发展压(LVDP)和左心室舒张末压(LVEDP),采用高效液相色谱仪测定心肌线粒体心磷脂含量.结果 与T1,2时比较,各组T3时HR、LVDP降低,LVEDP升高,心肌线粒体心磷脂含量降低(P<0.05);与C组比较,其余3组T3时HR、LVDP降低,LVEDP升高,心肌线粒体心磷脂含量降低(P<0.05);与I/R组比较,DZ组T3时HR、LVDP升高,LVEDP降低,心肌线粒体心磷脂含量升高(P<0.05);与DZ组比较,HD组T3时HR、LVDP降低,LVEDP升高,心肌线粒体心磷脂含量降低(P<0.05).结论 二氮嗪预处理可减轻大鼠离体心脏缺血再灌注损伤,与维持心肌线粒体心磷脂含量有关.     

线粒体ATP敏感性钾通道在缺血预处理保护硬化肝脏中的作用

目的 研究缺血预处理(IP)对肝硬化大鼠肝脏缺血/再灌注(I/R)损伤的保护作用,探讨线粒体ATP敏感性钾通道(mitoKATP通道)在这种保护机制中的作用.方法 复制雄性肝硬化SD大鼠,随机分为6组(每组8只).IP组以肝缺血5 min再灌注10 min作预处理;IP+5-HD组是在IP组基础上,使用微量注射泵经大鼠门静脉注射mitoKATP通道特异性阻滞剂5-HD进行预处理;DE组以静脉注射mitoKATP通道选择性开放剂DE作为预处理;DE+5-HD组是在DE组基础上再予静脉注射5-HD进行预处理;对照组(C组)以静脉注射等量生理盐水作为预处理;上述5组均在预处理后行肝缺血45 min再灌注60 min;缺血方式为70%肝脏热缺血.假手术组(S组)仅行开腹,不作任何其它处理.完成预定实验操作后分别取血用于血清谷丙转氨酶(ALT)与乳酸脱氢酶(LDH)检测,切取肝组织用于测定ATP酶活力、超氧化物岐化酶(SOD)活性、丙二醛(MDA)含量、湿重/干重(W/D)的测定及观察显微、超微结构变化.结果 C组ATP酶活性与肝损伤指标ALT与LDH活性、MDA含量与W/D比值均明显高于S组(P<0.01),肝脏在光镜与电镜下的显微与超微结构损伤明显;IP组与DE组的各项肝组织损伤指标均明显好于C组,ATP酶活性低于C组(P<0.05,P<0.01),而IP+5-HD组、DE+5-HD组的肝损伤指标分别差于IP组、DE组,ATP酶活性高于IP组、DE组(P<0.05,P<0.01);在SOD活性方面,C组明显低于S组(P<0.01),IP组低于S组,高于C组(P<0.01).DE组与C组相比无差异,IP+5-HD组、DE+5-HD组SOD活性分别与lP组、DE组相比无差异(P>0.05).结论 mitoKATP通道参与IP抗肝硬化大鼠肝I/R损伤的保护效应,其作用可能与下调肝组织ATP酶活性,减少ATP大量分解,改善肝能量代谢,增加能量储备;提高肝脏的抗氧化能力;改善肝组织微循环,减轻肝脏水肿有关.     

缺血后处理对缺血-再灌注心肌的保护作用及其与线粒体ATP敏感性钾通道的关系

目的探讨缺血后处理（IPo）的心肌保护作用及与心肌线粒体三磷酸腺苷（ATP）敏感性钾通道（mitoKATP）的关系,为药物后处理的研发提供依据。方法40只Wistar大鼠,建立大鼠离体心脏Langendorff灌注模型,采用随机数字表法分为5组,每组8只,正常对照组（NC组）：用K-H液持续灌注100min,不做任何处理;缺血-再灌注（I/R）组：全心缺血40min,再灌注60min;IPo组：全心缺血40min,再灌注10s,缺血10s,反复6次,然后持续再灌注58min;5-羟基癸酸（5-HD）组：全心缺血40min后,先用含5-HD（100μmol/L）的K-H液再灌注15min,再用不含5-HD的K-H液再灌注45min;IPo＋5-HD组：全心缺血40min后,先用含5-HD（100μmol/L）的K-H液再灌注10s,缺血10s,反复6次,再用含5-HD的K-H液持续灌注13min,然后用不含5-HD的K-H液再灌注45min。观察比较各组心功能、冠状动脉流量（CF）、冠状动脉流出液中心肌肌钙蛋白I（cTnI）含量、心肌梗死（AMI）面积和心肌细胞超微结构改变。结果再灌注末IPo组左心室发展压（74.3±3.3mmHgvs.57.1±3.3mmHg,t=13.00,P=0.000）、＋dp/dtmax（1706.6±135.6mmHg/svs.1313.3±96.2mmHg/s,t=6.28,P=0.000）、-dp/dtmax（1132.8±112.1mmHg/svs.575.7±67.7mmHg/s,t=13.48,P=0.000）、CF（6.49±0.30ml/minvs.3.70±0.24ml/min,t=28.60,P=0.000）与I/R组比较均升高;左心室舒张期末内压（10.9±1.7mmHgvs.26.2±1.5mmHg,t=-19.21,P=0.000）,冠状动脉流出液中cTnI含量（0.62±0.01ng/mlvs.0.71±0.01ng/ml,t=-12.00,P=0.000）均降低,AMI面积与I/R组比较减少20.8%（P〈0.05）。IPo＋5-HD组对心肌的保护作用与IPo组相似,但作用轻于IPo组。电子显微镜观察结果表明,IPo和IPo＋5-HD可减轻I/R引起的心肌纤维和线粒体损伤。结论IPo对I/R心肌有保护作用,其作用与mitoKATP的激活有关。     

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.