依托咪酯对大鼠海马脑片突触长时程增强的影响

目的 评价依托咪酯对大鼠海马脑片突触长时程增强(LTP)的影响.方法 雄性SD大鼠,断头后取出海马组织,制备厚400 μm的海马脑片.采用细胞外微电极记录技术,记录海马脑片CA1区细胞外群体峰电位(PS).取42张脑片,随机分为6组(n=7):用正常的人工脑脊液(ACSF)灌流海马脑片记录正常的PS,待其稳定后,对照组继续灌流ACSF,不同浓度依托咪酯组分别用含依托咪酯1μmol/L(依托咪酯 1 μol/L组)、2/μmol/L(依托咪酯2 μmol/L组)、5 μmol/L(依托咪酯5 μmol/L组)、10μmol/L(依托咪酯10 μmol/L组)、20 μmol/L(依托咪酯20 μmol/L组)的ACSF灌流,记录PS幅值.另取84张脑片,随机分为12组(n=7):用正常ACSF灌流海马脑片,记录稳定正常的PS 30 min,LIT组继续灌流ACSF,其余各组分别用含依托咪酯l μmol/L(LTP-依托咪酯 1 μmol/L组)、2 μmol/L(LTP-依托咪酯2μmol/L组)、5 μmol/L(LTP-依托咪酯 5 μmol/L组)、10μmol/L(LTP-依托咪酯 10 μmol/L组)、20 μmol/L(LTP-依托咪酯20 μmol/L组)、印防己毒素50 μmol/L(印防己毒素组)、荷包牡丹碱10 μmol/L(荷包牡丹碱组)、CGP35348 5 μmol/L(CGP35348 组)、印防己毒素50 μmol/L+依托咪酯10 μmol/L(印防己毒素+依托咪酯组)、荷包牡丹碱10 μmol/L+依托咪酯10 μmol/L(荷包牡丹碱+依托咪酯组)、CGP35348 5 μmol/L+依托咪酯10 μmol/L(CGP35348+依托咪酯组)的ASCF灌流,记录PS 30 min后,施以100 Hz的高频刺激(HPS),记录PS幅值.结果 与LTP组比较,LTP-依托咪酯2 μmol/L组、LTP-依托咪酯5 μmol/L组、LTP-依托咪酯10 μmol/L组、LTP-依托咪酯20 μmol/L组和CGP35348+依托咪酯组HIS后PS幅值降低(P＜0.05或0.01),印防己毒素组、荷包牡丹碱组、CGP35348组HFS后PS幅值差异无统计学意义(P＞0.05);与依托咪酯LTP 10μmol/L组比较,印防己毒素+依托咪酯组和荷包牡丹碱+依托咪酯组HIS后PS幅值增加(P＜0.01).结论 依托咪酯可通过激活大鼠海马GABAA受体抑制LTP的形成,从而影响学习和记忆功能.     

四种静脉麻醉药物对大鼠皮层脑片缺氧缺糖损伤的作用

目的 探讨四种常用静脉麻醉药物对大鼠皮层脑片缺氧缺糖损伤的作用。方法 建立大鼠皮层脑片缺氧缺糖损伤模型,设立对照组、缺氧缺糖损伤组、药物加损伤组,利用2,3,5-三苯基氯化四氮唑(TTC)染色定量比色方法,评价氯胺酮、异丙酚、咪达唑仑和硫喷妥钠对脑片损伤的保护作用。结果 随着缺氧缺糖损伤时间的延长,皮层脑片TTC染色程度明显降低,TTC染色反映的组织损伤百分率与孵育上清液乳酸脱氢酶(LDN)释放比活性呈正相关(r=0.9609,P<0.01)。对于缺氧缺糖损伤所致脑片TTC染色降低,不同浓度氯胺酮均能完全抑制;与损伤组比较。大剂量硫喷妥钠和咪达唑仑(400μmol·L~(-1)和10μmol·L~(-1)A值明显升高(P<0.01或0.05);小剂量异丙酚(1μmol·L~(-1))对脑片TTC染色降低无作用,大剂量(100μmol·L~(-1))加重TTC染色降低(P<0.01)。结论 对于大鼠皮层脑片缺氧缺糖损伤,四种静脉麻醉药物作用效果各不相同:临床麻醉剂量的氯胺酮具有明显保护作用,咪达唑仑和硫喷妥钠在超过临床使用范围的大剂量时有部分保护作用;大剂量异丙酚会加重大鼠皮层脑片的缺氧缺糖损伤。     

咪达唑仑对N-甲基-D-天冬氨酸所致PC12细胞损伤的保护作用

目的 观察静脉麻醉药咪达唑仑对N-甲基-D-天冬氨酸(NMDA)致PC12细胞损伤的保护作用,并探讨其可能的作用机理。方法 乳酸脱氢酶(LDH)法及MTT比色法判断细胞损伤程度及细胞存活率,Fura-2/AM荧光标记法测定细胞内Ca2+浓度([Ca2+]i),分光光度法测定细胞一氧化氮合酶(NOS)活性。结果 NMDA 300μmol·L-1处理4 h可明显导致PC12细胞的损伤,LDH释放量明显增加,存活细胞吸光度值OD570nm明显降低(P<0.01),[Ca2+]和NOS活性则明显增加(P<0.01)。咪达唑仑0.33～30μmol·L-1与NMDA 300μmol·L-1共同作用4 h后,除0.33 gmol·L-1组外,其他各剂量组均有较好的细胞保护作用,LDH明显降低而OD570nm显著增加(P<0.01)。咪达唑仑3和30 μmol·L-1均可显著降低NMDA诱导的[Ca2+].水平及NOS活性(P<0.01)。结论 咪达唑仑对NMDA所致PC12细胞损伤有明显的保护作用.可能与其抑制钙超载及NOS活性有关。     

不同剂量右美托咪定对大鼠海马神经元缺氧复氧损伤中线粒体分裂的影响

目的探讨不同剂量的右美托咪定(dexmedetomidine,Dex)在大鼠海马神经元缺氧复氧损伤中对线粒体分裂的影响。方法 24h内出生的雄性SD大鼠,断头分离海马区神经组织,收集获得神经元细胞进行培养,8d后培养的海马神经元随机分为六组:正常对照组(C组);赋形剂组(V组);缺氧复氧组(HR)组;缺氧复氧+右美托咪定组(D1、D2、D3)组。C组:正常培养;V组:不行缺氧复氧、加入赋形剂二甲基亚砜培养6h,浓度0.01%;HR组:氧糖剥夺法缺氧6h,复氧12h建立缺氧复氧损伤模型;D1、D2、D3组,于缺氧6h后分别加入右美托咪定0.1、1、10μmol/L。采用激光共聚焦显微镜观察各组神经元细胞质Ca2+荧光强度,采用ELISA法检测细胞钙调神经磷酸酶活性,采用透射电镜观察线粒体的超微结构,Western-blot法检测线粒体分裂蛋白Drp1、Fis1的含量。结果与C组比较,HR组、D1组、D2组和D3组线粒体超微结构破坏加重,Ca2+荧光强度、CaN活性明显增强,Fis1、Drp1蛋白含量明显升高(P0.05);与HR组比较,D1组、D2组和D3组线粒体超微结构破坏减轻,Ca2+荧光强度、CaN活性明显减弱,Fis1、Drp1蛋白含量明显降低(P0.05);与D1组和D3组比较,D2组线粒体结构更加完整,Ca2+荧光强度、CaN活性明显减弱,Fis1、Drp1蛋白含量明显降低(P0.05)。C组和V组各指标差异无统计学意义。结论右美托咪定0.1、1、10μmol/L可以减少大鼠海马神经元缺氧复氧损伤中线粒体的分裂,其中1μmol/L是最佳的保护浓度,其机制可能是与其抑制钙超载有关。     

咪达唑仑对新生大鼠心肌细胞缺氧/复氧时细胞凋亡的影响

目的 探讨咪达唑仑对新生大鼠心肌细胞缺氧/复氧时细胞凋亡的影响.方法 分离、培养出生2～4 d的Wistar大鼠心肌细胞,将培养融合的心肌细胞随机分为7组(n=7):正常对照组(C组)、缺氧/复氧组(HR组)、外周型苯二氮革类受体(PBR)拮抗剂PK 11195组(P组)、PBR激动剂Ro 5-4864组(R组)、咪达唑仑组(M组)、PK 11195+Ro 5-4864组(PR组)和PK 11195+咪达唑仑组(PM组).HR组缺氧30 min复氧2 h建立缺氧/复氧模型.P组、R组、M组、PR组、PM组在培养皿中分别加入终浓度为10-4mol/L的PK 11195、Ro 5-4864和咪达唑仑及相应混合药物共同孵育,30 min后行缺氧/复氧.复氧2 h时收集细胞,采用HTC-Annexin V/PI双标法检测细胞凋亡情况,计算细胞凋亡指数(AI);Western blot法测定心肌细胞蛋白激酶C(PKc)表达水平;Meta Flour单细胞内钙测定系统测定细胞内钙离子浓度.结果 与C组比较,其余各组AI升高,除R组外其余各组细胞内钙离子浓度升高,PKC表达下调(P<0.01);与HR组比较,R组AI和细胞内钙离子浓度降低,PKC表达上调,M组和PM组AI降低(P<0.01);与P组比较,R组AI和细胞内钙离子浓度降低,PKC表达上调(P<0.01),PR组、PM组差异无统计学意义(P>0.05);与R组比较,M组、PR组、PM组Al和细胞内钙离子浓度均升高,PKC表达下调(P<0.01).结论 咪达唑仑10-4mol/L可减轻新生大鼠心肌细胞缺氧/复氧时细胞凋亡,其作用机制可能是非PBR依赖性的,且与细胞内钙离子浓度和PKC表达无关.     

吗啡预处理减轻小鼠海马神经元氧-糖缺失/恢复损伤的影响因素

目的 探讨吗啡预处理减轻小鼠海马神经元氧-糖缺失/恢复损伤的影响因素(剂量和作用时间窗).方法 急性分离小鼠海马组织,制备脑片,行4部分实验,实验Ⅰ:应用吗啡0.1、0.3、0.5、1.0、3.0、10.0 μmol/L孵育脑片30 min,再常规培养30 min,缺氧无糖20 min,复氧复糖2 h.实验Ⅱ:应用吗啡3.0 μmol/L孵育脑片5、15、30、45、60 min,再常规培养30 min,缺氧无糖20 min,复氧复糖2 h.实验Ⅲ:应用吗啡3.0 μmol/L孵育脑片30 min,再常规培养即刻、5、15、30、60、120 min时行缺氧无糖20 min,复氧复糖2 h.实验Ⅳ:应用蛋白激酶C(PKC)非特异性抑制剂白屈菜赤碱10 μmol/L、选择性新奇型PKCε(nPKCε)抑制剂εVI.2 2 μmol/L、特异性钙-钙调蛋白依赖性蛋白激酶Ⅱ(CaMKⅡ)抑制剂AIP 2 μmol/L、N.甲基-D-天冬氨酸(NMDA)受体特异性阻断剂MK-801 10 μmol/L孵育脑片30 min,再与吗啡3.0 μmol,L共同孵育30 min,常规培养30 min,缺氧无糖20 min,复氧复糖2 h.计算神经元存活率.结果 与氧-糖缺失/恢复组比较,吗啡0.5、1.0、3.0、10.0 μmol/L预处理组、吗啡预处理15、30、45、60 min组、吗啡预处理后常规培养即刻、5、15、30、60 min组神经元存活率升高(P<0.05).PKC、nPKGt、CaMKⅡ抑制剂和NMDA受体阻断剂可部分抑制吗啡预处理升高神经元存活率的作用.结论 有效减轻小鼠海马神经元氧-糖缺失,恢复损伤的吗啡预处理方式为:浓度0.5～1.0 μmol/L,持续时间15～60 min,间隔时间小于60 min;其保护作用可能部分依赖于PKC、nPKCε、CaMKⅡ的活化和NMDA受体的激活.     

芬太尼对大鼠海马锥体神经元GABAA受体的作用

目的探讨芬太尼对大鼠海马锥体神经元GABAA受体的作用。方法采用酶-机械法急性分离出生3-10 d SD大鼠的海马锥体神经元,用全细胞膜片钳技术记录锥体神经元GABAA受体介导的Cl-电流(GABA电流,IGABA),不同浓度的GABA和1 μmol/L GABAA受体特异性拮抗剂荷包牡丹碱诱发并确定IGABA;用不同浓度的芬太尼和1．0 μmol/L μ受体特异性拮抗剂CTAP评价芬太尼对30 μmol/L GABA诱发IGABA的影响。结果 GABA诱发内向电流(IGABA),其EC50为23．73μmol/L,荷包牡丹碱阻断IGABA;芬太尼剂量依赖性地抑制IGABA,其EC50为0．011 μmol/L,并缩短IGABA的脱敏感时间常数τdes;CTAP使芬太尼抑制GABA诱发IGABA的EC50升至0．414μmol/L;芬太尼不改变IGABA的翻转电位 ECl-(-3．0mV)。结论芬太尼可抑制大鼠海马锥体神经元GABAA受体的功能。     

P2X受体在大鼠海马氧糖缺失时IL-1β合成和释放中的作用

目的 探讨P2X受体在大鼠海马氧糖缺失时IL-1β合成和释放中的作用.方法 成年雄性SD大鼠,体重150～200 g,制备海马脑片,取160张,随机分为4组(n=40),C组:用95%O2-5%CO2饱和aCSF孵育;OGD组:脑片移至经95%N2-5%CO2饱和的无糖aCSF中,并置于持续通入95%N2-5%CO2的容器内进行氧糖缺失处理;BBG组:脑片移至含P2X7受体特异性拮抗剂亮蓝G(BBG,终浓度1μmol/L)的经95%O2-5%CO2饱和的aCSF中,孵育20 min,随后进行氧糖缺失处理,无糖aCSF中加入终浓度1 μmol/L的BBG;OP组:脑片移至加入P2X4受体单克隆抗体(终浓度1.5μg/ml)的经95%O2-5%CO2饱和的aCSF中孵育60 min,随后进行氧糖缺失处理,无糖aCSF中加入终浓度1.5 μg/ml的P2X4受体单克隆抗体.于氧糖缺失前及氧糖缺失20、40和60 min时测定LDH和IL-1β的释放量,并观察病理学结果.于氧糖缺失60 min时测定细胞内IL-1β前体蛋白(pro-IL-1β)的表达水平.结果 与C组比较,其余各组LDH和IL-1β释放量升高,细胞内pro-IL-1β表达上调(P＜0.05);与OGD组比较,BBG组LDH和IL-1β释放量降低,细胞内pro-IL-1β表达上调(P＜0.05),OP组上述指标差异无统计学意义(P＞0.05).结论 P2X7受体介导了大鼠海马氧糖缺失时IL-1β的合成和释放,而P2X4受体没有介导IL-1β的合成和释放.     

几种静脉麻醉药对大鼠心室肌细胞游离钙离子移动的影响

目的　观察临床常用静脉麻醉药咪唑安定、异丙酚和依托咪酯对心肌细胞内钙离子移动的作用 ,探讨其对心肌收缩性的影响。方法　急性分离的大鼠单个心室肌细胞 ,采用 Fluo- 3 / AM为钙荧光指示剂 ,观察临床诱导峰浓度及 5倍峰浓度时咪唑安定 ( 3μm ol· L- 1 或 15μmol· L- 1 )、异丙酚( 5 0μm ol· L- 1 或 2 5 0μmol· L- 1 )或依托咪酯 ( 3μmol· L- 1 或 15μmol· L- 1 )对高浓度 KCl或咖啡因所诱发细胞内钙离子浓度变化的影响。结果　临床诱导峰浓度异丙酚明显减弱 KCl所诱发的钙离子跨膜内流 ( P<0 .0 5 ) ,而咪唑安定和依托咪酯 ( 3 μm ol· L- 1 )有减弱钙离子跨膜内流趋势 ;而超临床浓度的咪唑安定、异丙酚和依托咪酯明显减弱 KCl所诱发钙离子跨膜内流 ( P<0 .0 5 )。上述两种浓度咪唑安定、异丙酚或依托咪酯对咖啡因所致胞浆内钙离子的增加均无明显影响 ( P>0 .0 5 )。结论　上述几种静脉麻醉药具有剂量依赖性地减少心肌细胞钙离子跨膜内流作用 ,以异丙酚影响最显著 ,咪唑安定次之 ,依托咪酯较弱 ,但对心肌细胞肌浆网功能尚无明显影响     

活性氧在缺氧后处理激活大鼠心肌细胞Nrf2/ARE信号通路中的作用

目的评价活性氧(ROS)在缺氧后处理激活大鼠心肌细胞核因子E2相关因子2(Nrf2)/抗氧化反应元件(ARE)信号通路中的作用。方法分离、培养成年大鼠原代心肌细胞, 采用随机数字表法分成4组(n=20):正常组(N)、缺氧复氧组(HR组)、缺氧后处理组(HPO组)及HPO+ROS清除剂组(HPO+MPG)。采用缺氧45 min复氧60 min的方法制备心肌细胞缺氧复氧损伤模型;HPO组缺氧45 min后, 行3个循环的氧合5 min-缺氧5 min处理, 再复氧60 min;HPO+MPG组缺氧35 min时加入ROS清除剂N-(2-硫基丙酰)-甘氨酸(终浓度2 mmol/L)继续缺氧处理10 min, 余同HPO组。于复氧末, 检测心肌细胞内Ca2+水平和Nrf2活性, 观察心肌细胞超微结构并进行线粒体Flameng评分;采用Western blot法和RT-PCR法分别检测心肌细胞Nrf2、醌氧化还原酶(NQO1)、SOD1、血红素加氧酶1(HO-1)及其mRNA表达。结果与N组比较, HR组心肌细胞内Ca2+水平、Nrf2活性和Flameng评分升高, Nrf2、NQO1、SOD...     

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.     

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.     

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.     

Dilemma of Membrane Biocompatibility and Reuse

Abstract: Numerous articles have been published on the multiple use of dialyzers and on the effect of different reprocessing chemicals and techniques on the dialyzer biocompatibility and performance. The results often appear contradictory, especially those comparing standard biocompatibility parameters. Despite this confusion, a discerning review of the published works allows certain limited conclusions to be drawn. Reprocessing of used hemodialyzers changes the biocompatibility profile of a dialyzer as defined by the parameters complement activation. leukopenia, and cytokine release. The effect of reprocessing depends on the chemicals and reprocessing technique applied and also on the type of membrane polymer being subjected to the reprocessing procedure. Reports of pyrogenic reactions indicate that the flux of the membrane also influences how suitable it is for safe reuse. An increased risk of allergic and pyrogenic reactions appears to be associated with dialyzer reuse. Furthermore, there has been a lack of investigations into the immunologic effect of the layer of adsorbed and chemically altered proteins that remains on the inner surface of reprocessed dialyzers. We conclude that the clinical benefit of dialyzer reuse cannot be generally accepted from a biocompatibility point of view.     

The analgesic effect of racemic ketamine in patients with chronic ischemic pain due to lower extremity arteriosclerosis obliterans

Background : Ketamine in sub-dissociative doses has been shown to have analgesic and phantom-Limb pain, where conventional treatment has often failed. Chronic ischemic pain due to lower extremity arteriosclerosis obliterans often responds poorly to analgesics, and the pain-generating mechanisms are not well understood.
Methods : Eight patients with rest pain in the lower extremity due to arteriosclerosis obliterans were given sub-dissociative doses of 0.15, 0.30, or 0.45 mg/kg racemic ketamine and morphine 10 mg as a 5-min infusion on four separate days in a cross-over, double-blind, randomised protocol. Plasma levels of (S)- and (R)-ketamine and their nor-metabolites were analysed with an enantioselective high-performance liquid chromatography (HPLC) method. Pain levels were evaluated with a visual analogue scale (VAS).
Results : Individual pain levels were highly variable during and after all the infusions but the pooled pain levels showed a dose-dependent analgesic effect of ketamine with a transient but complete pain relief in all patients at the highest dose (0.45 mg/ kg). Side-effects, mainly disturbed cognition and perception, were pronounced and dose-dependent. Morphine 10 mg had an analgesic peak at 20 min and 5/8 patients had complete pain relief. The remaining 3 patients also had high baseline pain scores, indicating a higher analgesic potency for the 0.30 and 0.45 mg/ kg ketamine doses than for morphine 10 mg.
Conclusion : We have demonstrated a potent dose-dependent analgesic effect of racemic ketamine in clinical ischemic pain. Due to a narrow therapeutic window, this analgesic effect is probably best utilised in combination with other analgesics.