低温生理盐水与腺苷局部灌注对脊髓缺血损伤的保护作用

目的 研究低温生理盐水和腺苷对兔主动脉阻断致脊髓缺血损伤的保护作用。方法 30只成年健康新西兰白兔随机分成3组,每组10只。A组：作为缺血对照：B组,用低温生理盐水局部灌注;C组：用低温生理盐水和腺苷局部灌注。通过阻断兔贤动脉水平的腹主动脉60分钟建立兔脊髓缺血损伤模型。观察3组血流动力学指标,脊髓自由基含量、术后Tarlov评分和脊髓组织病理学改变。结果 3组心率比较均无差异,C组血压于阻断腹主动脉20分钟时下降（P＜0．05）;A组丙二醛增加,超气门物歧化酶减少,而B组和C组变化较轻;A组大部分发生截瘫,B组后肢功能部分恢复,C组后肢功能恢复良好;病理检查示A组中央灰质聚集性坏死,巨噬细胞浸润,尼氏小体消失,核仁模糊,B组和C组脊髓结构较完整。结论 低温生理盐水和腺苷局部灌注具有良好的脊髓保护作用,其方法简便。腺苷可减少三磷酸腺苷（ATP）的耗竭,促进其恢复,并具有神经保护作用。     

不同高压氧预处理方案对兔脊髓缺血再灌注损伤的影响

目的 探讨不同高压氧预处理方案对兔脊髓缺血再灌注损伤的影响.方法 新西兰大白兔45只,月龄4～5月,体重2.0～2.5 kg,随机分为5组:假手术组(S组,n=5)开腹剥离左肾动脉下段腹主动脉但不阻断血流,20 min后关腹;脊髓缺血再灌注组(IR组,n=10)采用左肾动脉下段腹主动脉阻断法建立脊髓缺血再灌注损伤模型,缺血20 min后恢复灌注;不同方案高压氧预处理组(H_(1～3)组,n=10)分别接受连续5 d(H_1组)、10 d(H_2组)或20 d(H_3组)高压氧预处理(2.5 ATA,吸入氧浓度100%),1h/d,末次高压氧预处理结束后24 h时,建立脊髓缺血再灌注模型.再灌注48 h时,采用修正Tarlov评分,评价后肢运动功能.然后取L_5脊髓节段,分别行HE、TUNEL和nuoro-Jade B染色,计数脊髓正常神经元、凋亡神经元和变性神经元.结果 与S组比较,IR组后肢运动功能评分和脊髓前角正常神经元计数降低(P<0.01);与IR组比较,H_1组和H_2组后肢运动功能评分和脊髓前角正常神经元计数升高,凋亡神经元计数和变性神经元计数降低(JP<0.01),H_3组各指标差异无统计学意义(P>0.05);H_1组和h_2组各指标比较差异无统计学意义(P>0.05);与H_1组和H_2组比较,H_3组后肢运动功能评分和脊髓前角正常神经元计数降低,凋亡神经元计数和变性神经元计数升高(P<0.01).结论 连续5 d或10 d高压氧预处理(2.5 ATA,吸入氧浓度100%)可减轻脊髓缺血再灌注损伤;而连续20 d高压氧预处理无神经保护作用.     

脊髓缺血性损伤时脑源性神经营养因子、丝氨酸/苏氨酸蛋白激酶ε蛋白和mRNA含量的变化及远程缺血预处理干预作用

目的探讨远程缺血预处理(RIPC)对兔脊髓缺血再灌注损伤(SCIRI)时脑源性神经营养因子(BDNF)、丝氨酸/苏氨酸蛋白激酶(PKC)ε蛋白和mRNA含量的影响及其意义。方法日本大耳白兔36只,随机均分为假手术组(S组)、缺血性损伤组(IR组)、IR+RIPC组。每组6只动物分别于再灌注第2天和第5天处死。S组不阻断腹主动脉,IR组和IR+RIPC组夹闭腹主动脉30分钟建立SCIRI模型,IR+RIPC组于主动脉阻断前1小时实施RIPC。3组动物在再灌注第2天和第5天行后肢神经功能评分后处死并取脊髓组织L3-L5段,评估病理学变化;用Western blotting和RT-PCR法分别检测脊髓组织BDNF、PKCε蛋白及其mRNA含量。结果同一时间点,与IR组相比,IR+RIPC组后肢神经功能评分和脊髓组织病理切片分级明显改善(P0.05),脊髓组织BDNF、PKCε蛋白及mRNA表达均明显升高(P0.05)。结论 RIPC对兔SCIRI有一定的防治作用,其作用机制与RIPC激活了PKCε/PKC信号通路,进而上调脊髓损伤区域BDNF蛋白的表达有关。     

腹主动脉局部灌注丙泊酚减轻脊髓缺血-再灌注损伤的研究

目的 建立兔脊髓缺血-再灌注损伤模型，研究经腹主动脉局部灌注丙泊酚对脊髓缺血-再灌注损伤的作用。方法 新西兰大耳白兔30只，随机均分为A、B、C三组，诱导后气管插管，持续监测平均动脉压、心率、脉搏血氧饱和度及肛温。左股动脉切开置管至腹主动脉分出左肾动脉远端1．0cm处，于左肾动脉开口远端0．5cm处阻断腹主动脉，同时阻断双侧髂总动脉，自阻断即刻开始经置入导管分别向阻断的腹主动脉远端灌注5ml／kg丙泊酚溶液（A组）、10％脂肪乳（B组）和生理盐水（C组），30min后开放。于动物完全清醒即刻、再灌注后6、24和48h对双后肢神经功能进行评分，光镜观察脊髓前角正常运动神经元并计数。结果 清醒即刻、再灌注后6、24和48hA组神经行为学评分明显高于B和C组（P〈0．05），B、C两组比较差异无统计学意义。三组脊髓前角正常运动神经元中位数分别为11、1和0，A组明显高于B、C两组（P〈0．05）。结论 腹主动脉阻断期间经阻断的腹主动脉局部灌注丙泊酚可减轻脊髓缺血一再灌注损伤。     

丙泊酚对家兔脊髓缺血-再灌注损伤的保护作用

目的 观察丙泊酚对脊髓组织中低氧诱导因子-1α(HIF-1α)的变化以及神经行为学和脊髓组织病理学改变,探讨丙泊酚对脊髓缺血-再灌注损伤的保护作用.方法 60只新西兰大白兔随机均分为三组:缺血-再灌注组(A组)、缺血-再灌注+英脱利匹特组(B组)、缺血-再灌注+丙泊酚组(C组).采用球囊压迫法建立兔脊髓缺血-再灌注模型.采用Tarlov评分法评价兔复灌后48 h神经行为学功能,显微镜下观察L4～L6脊髓组织的病理生理学改变,采用免疫组化法监测复灌后48、72 h及1周HIF-1α的变化.结果 C组48 h神经行为学Tarlov评分[(3.0±1.3)分]明显高于A组[(1.0±1.2)分]和B组[(1.0±1.1)分](P<0.05),A组与B组差异无统计学意义.神经元计数C组(8.5±3.5)显著高于A组(2.3±2.1)和B组(2.2±2.0).C组HIF-1α表达较其它两组明显增加(P<0.05).结论 丙泊酚能增加脊髓组织HIF-1α的表达,可能促进下游靶基因的表达,使受损组织的血管再生与重建,从而发挥对脊髓缺血-再灌注损伤的保护作用.     

异丙酚腹主动脉灌注和静脉输入在兔脊髓组织内药物浓度的比较

目的 测定腹主动脉灌注与静脉输入异丙酚在缺血再灌注脊髓损伤组织内的药物浓度,探讨其可能的作用部位.方法 取健康4～6月龄新西兰大白兔46只,体重2.0～2.5 kg,随机分为生理盐水组(N组,n=10)、异丙酚腹主动脉灌注组(A组,n=18)、异丙酚静脉输入组(V组,n=18)组.建立肾下腹主动脉阻断脊髓缺血再灌注损伤模型,A组经腹主动脉阻断远端持续泵入异丙酚(50 mg/kg)30 min,N组泵入同等容量的生理盐水,V组经静脉持续泵入异丙酚(50 mg/kg)30 min.测定再灌注即刻A组和V组L4～6节段和T6～8节段的脊髓组织中异丙酚浓度,观察再灌注后48 h 3组动物的神经行为学评分和组织病理学变化,并计数脊髓前角正常神经元.结果 3组在腹主动脉阻断后平均动脉压均有一定程度的降低,其中V组降低幅度最明显,阻断5min后显著低于N组,阻断10min后低于同时间点A组(P＜0.05);A组在阻断15 min后显著低于N组(P＜0.05).N、A组组内不同时间点心率与基础心率比较差异无统计学意义(P＞0.05);V组于阻断期间心率增加明显,于阻断15 min开始心率明显高于同时间点的N组和A组(P＜0.05).A组与N组间心率比较差异无统计学意义(P＞0.05),A组L4～6节段脊髓组织异丙酚浓度为(26 950.5±30 242.3)ng/g,显著高于T6～8节段的(3 587.4±2 479.3)ng/g、V组L4～6节段的(3 045.9±2 252.9)ng/g及T6～8节段的(3 181.1±1 720.9)ng/g,比较差异有统计学意义(P＜0.05).神经行为学观察显示,A组动物术后截瘫率为30%,明显低于N组的80%和V组的100%,差异有统计学意义(P＜0.05);N、V组间比较差异无统计学意义(P＞0.05).A组脊髓前角正常神经元计数为8.4(4.0～11.5),明显多于N组的2.2(0～4.3)和V组的1.9(0～4.0),差异有统计学意义(P＜0.05),N、V组间比较差异无统计学意义(P＞0.05).结论 异丙酚腹主动脉灌注较静脉输入能获得更高的靶器官药物浓度,对缺血再灌注损伤脊髓具有更好的保护作用.     

静脉输注艾司洛尔对脊髓缺血再灌注损伤大鼠脊髓组织HIF-1α表达的影响

目的 评价静脉输注艾司洛尔对脊髓缺血再灌注损伤大鼠脊髓组织低氧诱导因子-1α表达( HIF-1α)的影响.方法 健康雄性Wistar大鼠36只,体重300～350 g,采用随机数字表法,将其随机分为3组(n=12):假手术组(S组)、脊髓缺血再灌注组(1R组)和艾司洛尔组(E组).采用夹闭肾下腹主动脉20 min再开放的方法制备脊髓缺血再灌注损伤模型.E组缺血前30 min静脉输注艾司洛尔200 g·kg-1·min-1,输注时间为1h;IR组静脉输注等容量生理盐水,输注时间为1h;S组不阻断腹主动脉,于分离腹主动脉后输注等容量生理盐水,输注时间为1h.再灌注24和48 h时随机抽取大鼠6只,采用Tarlov评分法评价后肢运动功能,然后处死大鼠,取L4,5脊髓组织,光镜下观察病理学结果,采用免疫组化法测定HIF-1α表达水平.结果 与S组比较,IR组各时点HIF-1α表达上调,Tarlov评分降低(P＜ 0.05),E组HIF-1α表达上调(P＜0.05),Tarlov评分差异无统计学意义(P＞0.05);与IR组比较,E组各时点HIF-1α表达上调,Tarlov评分升高(P＜0.05),脊髓病理学损伤j减轻.结论 静脉输注艾司洛尔可减轻大鼠脊髓缺血再灌注损伤,其机制与其上调脊髓组织HIF-1α的表达有关.     

异丙酚对脊髓兴奋性氨基酸含量的影响

目的 观察异丙酚对兔缺血再灌注损伤脊髓的保护作用以及对兴奋性氨基酸(excitatory amino acid,EAA)的影响.方法 健康新西兰大白兔60只,雌雄各半,体重2.0～2.5 kg.采用左肾下腹主动脉阻断法建立脊髓缺血再灌注损伤模型,阻断开始即泵入灌注液6 mL/kg(不足部分均以10%脂肪乳补充),灌注速度12 mL/(kg·h),30 min后停止灌注,开放腹主动脉.根据灌注液的不同,随机分为生理盐水组(A组)、10%脂肪乳组(B组)、30 mg/kg异丙酚组(C组)、40 mg/kg异丙酚组(D组)、50 mg/Kg异丙酚组(E组)及60 mg/kg异丙酚组(F组),每组10只.分别记录麻醉清醒即刻、再灌注后6、24和48 h兔神经行为学评分;于再灌注后48 h取L4～6节段脊髓组织计数脊髓前角正常神经元;采用高效液相色谱法测定脊髓组织中EAA含量.结果 C、D、E、F组各时间点神经行为学评分明显优于A、B组(P＜0.05),E组评分最高(P＜0.05),A、B组间差异无统计学意义(P＞0.05).C、D、E、F组脊髓前角正常神经元明显多于A、B组(P＜0.05),且E组多于C、D、F组(P＜0.05).A、B、C、D、E、F组脊髓组织EAA含量均明显高于正常值,其中A、B组最高(P＜0.05),但A、B组间差异无统计学意义(P＞0.05);E组最低(P＜0.05).谷氨酸、天门冬氨酸含量均与脊髓前角正常神经元计数及再灌注后48 h神经行为学评分成负相关,相关系数分别为-0.613、-0.536、-0.874及0.813(P＜0.01).结论 异丙酚能降低缺血再灌注脊髓组织中EAA含量,减轻脊髓缺血再灌注损伤.     

缺血后处理对兔脊髓缺血-再灌注损伤的保护作用

目的研究缺血后处理是否可以减轻兔脊髓缺血再灌注的损伤。方法雄性新西兰大白兔30只,随机分为五组,每组6只。假手术组(N1组)仅行单纯手术操作但不阻闭腹主动脉;对照组(N2组)行单纯缺血再灌注;缺血后处理15s/30s/60s(PA/PB/PC组)分别于阻闭腹主动脉15min后,再灌注15s/30s/60s,缺血15s/30s/60s,反复3次。再灌注48h时对所有动物的后肢运动功能进行评分并行脊髓前角正常神经元计数。结果PB组再灌注48h后肢运动功能评分[3.5(2～4)分],明显高于N2组[2(1～3)分](P<0.05),其他各组与N2组相比差异无显著意义。脊髓前角正常神经元计数PB组为36.7±7.0,明显多于N2组25.7±4.3(P<0.01),而PA组18.2±2.2和PC组8.0±4.1则明显少于N2组(P<0.05)。结论缺血后处理对兔脊髓缺血再灌注损伤的作用取决于后处理时间,缺血后处理30s/30s对脊髓缺血再灌注损伤具有保护作用,而缺血后处理15s/15s和60s/60s会加重脊髓损伤。     

抑肽酶预处理对兔脊髓缺血再灌注损伤的影响

目的:观察抑肽酶预处理对兔脊髓缺血再灌注损伤的影响,为临床应用抑肽酶治疗脊髓缺血再灌注损伤提供实验依据.方法:6月龄国产大耳白兔39只,随机分为A组(15只)、B组(15只)和C组(9只).A、B组动物于左肾动脉下用主动脉环扎器环扎腹主动脉,缺血60min后开放,再灌注24h.A组于缺血前10min静脉注射抑肽酶3×107IU/kg,继而用Graseby 3500微量泵持续注入抑肽酶1×107IU/(kg·h)至处死动物时;B组用生理盐水代替A组的抑肽酶,其余同A组;C组只暴露不夹闭腹主动脉,不给药.A、B组缺血前,缺血5、10、20、60min及再灌注后8h、24h,C组相应时间点,测定各组皮层体感诱发电位(CSEP).A、B组缺血前,缺血再灌注后8h、24h,C组相应时间点,处死动物,取L2～L4脊髓行一氧化氮(NO)及一氧化氮合酶(NOS)测定,取L3～L4脊髓灰质切片进行组织学检查,观察神经无形态变化.结果:A、B两组缺血5min时CSEP的P1波和N1波潜伏期较缺血前延长、波幅降低(P<0.05),缺血20min时两波潜伏期及波幅消失,缺血冉灌注后8h两波潜伏期及波幅有所恢复,但较缺血前及缺血后5min、10min时明显延长和降低(P<0.01),缺血再灌注后24h两波潜伏期及波幅较前面各时间点延长和降低(P<0.01);缺血再灌注后8h、24h,A组较B组P1波和N1波潜伏期短、波峰高(P<0.05),而C组较A、B组潜伏期短、波峰高(P<0.01).A、B两组NO、总NOS及诱导型NOS(iNOS)在缺血再灌注后8h明显升高,24h时更高(P<0.05),在缺血再灌注后8h、24h时A组的NO、总NOS及iNOS较B组低(P<0.01).各时间点C组P1波和N1波潜伏期及波幅不变,NO、总NOS及iNOS量均不变(P>0.05).A、B组脊髓缺血再灌注后神经元均有损伤,但在再灌注后8h、24h时A组神经元损伤程度均较B组为轻:C组神经元正常.结论:抑肽酶预处理可以改善脊髓缺血再灌注早期的CSEP,减少NO含量,从而减少缺血再灌注损伤.     

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 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.     

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.