异丙酚对小鼠海马脑片CREB磷酸化水平的影响

目的 评价异丙酚对小鼠海马脑片cAMP反应元件结合蛋白(CREB)磷酸化水平的影响.方法 BALB/C小鼠,体重18～22 g,雌雄不拘,迅速断头取脑,将其海马切成450 μm厚的脑片.42张脑片,分别随机用不同浓度(10-9、10-8、10-7、10-6、10-5和10-4 mol/L)异丙酚孵育1 h,每个浓度6张脑片,另外6张脑片,不用异丙酚孵育,作为正常对照.70张脑片,其中63张脑片以5×10-6 mol/L异丙酚孵育,分别于异丙酚孵育1、2、5、7、9、12、15、30和60 min随机取出7张脑片,另外7张脑片,不用异丙酚孵育,作为正常对照;35张脑片以5×10-6 mol/L异丙酚孵育5 min后,用人工脑脊液洗脱异丙酚,分别于洗脱2、4、7、10、25 min随机取出7张脑片.采用聚丙烯酰胺凝胶电泳和蛋白质印迹法测定脑片CREB磷酸化水平.结果 与正常对照比较,10-9～10-4 mol/L异丙酚可降低脑片CREB磷酸化水平,5×10-6 mol/L异丙酚孵育1～60 min可降低CREB磷酸化水平,5×10-6 mol/L异丙酚孵育5 min后,用人工脑脊液洗脱2～7 min时,CREB磷酸化水平未恢复(P＜0.05或0.01),用人工脑脊液洗脱10、25 min时,CREB磷酸化水平恢复(P＞0.05).结论 异丙酚可抑制小鼠海马脑片CREB磷酸化,这可能是其抑制记忆功能的机制之一.     

吗啡预处理对小鼠海马脑片氧-糖缺失/恢复时CaMKⅡ和NMDA受体的影响

目的 评价吗啡预处理对小鼠海马脑片氧-糖缺失，恢复时钙，钙调蛋白依赖性蛋白激酶Ⅱ（CaMKⅡ）膜转位及N-甲基-D-天冬氨酸（NMDA）受体磷酸化的影响。方法成年BALB／C小鼠，体重18-22g，雌雄不拘。每次将5只小鼠同批断头取脑，制备海马脑片，随机分为5组：正常对照组（Ⅰ组）、氧．糖缺失，恢复组（Ⅱ组）、吗啡预处理组（Ⅲ组）、纳络酮＋吗啡预处理组（Ⅳ组）及纳络酮预处理组（Ⅴ组）。Ⅰ组脑片正常体外培养，假操作换液。Ⅲ、Ⅳ、Ⅴ组小鼠海马脑片分别作相应预处理30min，间隔30min。Ⅱ、Ⅲ、Ⅳ、Ⅴ组建立小鼠海马脑片体外缺血再灌注损伤模型，分别氧-糖缺失20min，氧-糖恢复2h。各组于氧．糖缺失前即刻（T0）、氧-糖缺失20min（T1）、氧-糖恢复1h（T2）和2h（T3）取若干脑片匀浆、超声粉碎、离心，分离胞浆蛋白和膜相关蛋白；部分脑片分离总蛋白，Western blot检测CaMKⅡα蛋白表达量以及NMDA受体NR1亚单位的磷酸化。结果 海马脑片在T1、T2．T3时，CaMKⅡα膜相关蛋白含量增多。同时胞浆蛋白含量减少（P〈0．05）；T2、T3时，NMDA受体NR1亚单位磷酸化水平增高（P〈0．05）；而吗啡预处理明显地抑制上述CaMKⅡα膜转位及NMDA受体NR1亚单位磷酸化（P〈0．05）。纳络酮完全阻断吗啡预处理对CaMKⅡα膜转位及NR1磷酸化的抑制作用（P〈0．05）。CaMKⅡα总蛋白表达水平未见明显变化。结论 CaMKⅡ膜转位的抑制及NMDA受体磷酸化的抑制在吗啡预处理对小鼠海马脑片缺血再灌注的脑保护作用机制中起重要作用。     

异丙酚对N-甲基-D-天冬氨酸诱发大鼠海马神经元内游离钙离子浓度的影响

目的观察异丙酚对N-甲基-D-天冬氨酸（NMDA）诱发大鼠海马神经元内游离钙离子浓度（[Ca^2＋]i）的影响。方法取当天新生的Wistar大鼠海马神经元，培养12d随机分为5组，对照组（C组）、NMDA组、异丙酚10μmol／L＋NMDA组（P1组）、异丙酚100μmol／L＋NMDA组（P2组）、异丙酚400μmol／L＋NMDA组（P3组）。NMDA组培养液中加入NMDA至终浓度20μmol／L，P1组、P2组及P3组加入NMDA前即刻分别加入异丙酚至终浓度为10、100、400μmol／L，加入异丙酚后11min用激光共轭聚焦显微技术测定[Ca^2＋]。结果NMDA可诱发海马神经元[Ca^2＋]．升高，预先加入异丙酚100、400μmol／L可抑制这种改变，异丙酚10μmol／L对NDMA诱发的上述改变无影响。结论高浓度异丙酚可抑制NMDA诱发的大鼠海马神经元细胞[Ca^2＋]．的升高，这可能是其神经保护作用的机制之一。     

血管紧张素Ⅱ对增生性瘢痕成纤维细胞细胞外信号调节激酶活性的影响

目的：本研究硼察血管紧张素Ⅱ（angiotensinⅡ,AngⅡ）对增生性瘢痕成纤维细胞细胞外信号调节激酶（extracellular　signal-regulated kinase，ERK）活性的影响，旨在探讨其影响增生性瘢痕成纤维细胞生物学行为的信号机制。方法：取自愿捐献的增生性瘢痕组织标本，采用胶原酶法行成纤维细胞培养。用免疫荧光组织化学法检测细胞AT1和AT2受体的表达。取第3～4代细胞，并按实验设计，分别加入10^-2mol／L Ang Ⅱ，10^-7mol／L Ang Ⅱ＋10μmol／L Valsartan，10^-7mol／L Ang Ⅱ＋10μmol／L PD123319，10μmol／L Valsartan，10μmol／LPD123319共5组：对照组仅加入等量DMEM。以Western Blot法检测培养的细胞细胞外信号调节激酶（extracellular Signal-regulated kinases，ERK）活性变化，观察在阻断AT1或AT2受体情况下AngⅡ对培养的瘢痕成纤维细胞ERK磷酸化的影响。结果：免疫荧光组织化学染色结果显示培养的增生性瘢痕成纤维细胞同表达AT1和AT2受体。AngⅡ可增加培养的增生性瘢痕成纤维细胞ERK磷酸化。在一定剂量范围内，AngⅡ浓度增加，细胞ERK磷酸化程度增加。与对照组比较10^-7mol／L Ang Ⅱ显著增加瘢痕成纤维细胞ERK磷酸化，且差异有统计学意义（P〈0．05）。10μmol/L AT2受体拮抗剂PD1233191可显著增强AngⅡ诱导的细胞ERK磷酸化（P〈0．05）：10μmol／L的AT1受体拮抗剂Valsattan可显著抑制AngⅡ诱导的细胞ERK磷酸化；Valsattan或PD1233191单独刺激细胞并未明显影响ERK磷酸化（P〉0．05）。应用抗ERK抗体显示各组ERK含量一致。结论：AngⅡ通过其受体AT1和AT2可调控增生性瘢痕成纤维细胞ERK磷酸化，AngⅡ对增生性瘢痕成纤维细胞ERK活性的影响可能是AngⅡ调控增生性瘢痕成纤维细胞生物学行为可能的信号机制之一。     

异丙酚对大鼠海马CA1区神经元兴奋性突触传递的影响

目的 研究异丙酚对大鼠海马CA1区神经元兴奋性突触后电流（EPSC）和自发性兴奋性突触后电流（sEPSC）的影响。方法 Wistar大鼠断头后分离海马脑组织，制成400μm厚度的海马脑片，脑片随机分为5组（n=10）。脂肪乳剂Ⅰ组、异丙酚Ⅰ组、SR95531＋异丙酚组：记录EPSC10min（基础值）后分别加入10％脂肪乳剂90μl,1％异丙酚90μl（相当于100μmol／L）、10μmol／LSR95531＋100μmol/L异丙酚，继续记录EPSC40min，分析EPSC幅值的变化。脂肪乳剂Ⅱ组、异丙酚Ⅱ组：细胞破膜后稳定10．15min，分别加入10％脂肪乳剂90出和1％异丙酚90出，记录sEPSC40min，分析sEPSC频率、幅值和半衰期的变化。膜钳制电压均为-70mV。结果 与基础值比较，给药后脂肪乳剂Ⅰ组和SR95531＋异丙酚组EPSC幅值差异无统计学意义，异丙酚Ⅰ组EPSC幅值降低；给药后异丙酚Ⅰ组EPSC幅值比脂肪乳剂Ⅰ组降低（P〈0．05）。与脂肪乳剂Ⅱ组比较，异丙酚Ⅱ组sEPSC的频率、幅值降低、半衰期缩短（P〈0．05）。结论 异丙酚主要通过增强大鼠海马CA1区神经元突触前膜和突触后膜的GABA．受体活性，产生突触前抑制和突触后抑制，从而抑制兴奋性突触传递。     

ERK1/ERK2磷酸化在西地那非抑制猪肺动脉平滑肌细胞增殖中的作用

目的探讨丝裂原激活的蛋白激酶-44/蛋白激酶-42（ERK1/ERK2）磷酸化在西地那非抑制猪肺动脉平滑肌细胞增殖中的作用。方法体外原代培养猪肺动脉平滑肌细胞。细胞培养到3～5代后用于实验。随机分为4组：对照组（C组）、血小板衍生生长因子（PDGF）组（P组）、西地那非干预组（PS1组和PS2组）,P组细胞用20 ng/ml PDGF孵育,PS1组和PS2组在加入PDGF前20 min分别加入24、96μmol/L西地那非。于加入PDGF后1 h测定ERK1/ERK2磷酸化水平;于加入PDGF后24 h掺入5-溴脱氧尿嘧啶核苷（5-BrdU）,计算5-BrdU阳性细胞百分率,反映细胞DNA合成水平,并测定增殖细胞核抗原（PCNA）蛋白表达;于加入PDGF后3 d测定细胞增殖程度。结果与C组比较,P组、PS1组和PS2组ERK1/ERK2磷酸化水平、PCNA表达、5-BrdU阳性细胞百分率及细胞增殖率增加（P＜0．05或0．01）,PS1组和PS2组ERK1/ERK2磷酸化水平、PCNA表达、5-BrdU阳性细胞百分率及细胞增殖率低于P组（P＜0．05或0．01）,各组间总ERK1/ERK2水平差异无统计学意义（P＞0．05）。结论西地那非通过抑制ERK1/ERK2的磷酸化,下调PCNA的表达,抑制了DNA的合成,从而抑制了PDGF诱导猪肺动脉平滑肌细胞的增殖。     

P2X7受体在大鼠海马脑片和神经元突触体氧糖缺失时谷氨酸和γ-氨基丁酸释放中的作用

目的 评价P2X7受体在大鼠海马脑片和神经元突触体氧糖缺失(OGD)时谷氨酸(Glu)和γ-氨基丁酸(GABA)释放中的作用.方法 健康成年雄性SD大鼠,体重150～200 g,制备海马脑片和神经元突触体,放入95%O2-5%CO2预充饱和人工脑脊液(aCSF)中35 ℃下孵育30 min后,取大鼠海马脑片96张,随机分为3组(n=32);取大鼠海马神经元突触体72份,随机分为3组(n=24).对照组(C组)于95%O2-5%CO2预充饱和的aCSF中孵育60 min;OGD组于95%N2-5%CO2预充饱和的乏糖aCSF中35 ℃下孵育60 min;亮蓝G组(BBG组)于预先加入P2X7受体拮抗剂亮蓝G 1 μmol/L、95%O2-5%CO2预充饱和的aCSF中孵育20 min,随后移至2 ml含亮蓝G l μmol/L、95%N2-5%CO2预充饱和的乏糖aCSF中孵育60 min.于OGD即刻、20、40、60 min(T1-4)时,分别随机取海马脑片和神经元突触体各6份,测定Glu和GABA的释放量.各时点分别取海马脑片2张,光镜下观察病理学结果.结果 与C组比较,OGD组和BBG组T2-4时海马脑片Glu和GABA释放量增加(P＜0.05);与OGD组比较,BBG组T3-4时海马脑片Glu释放量减少,T4时GABA释放量减少(P＜0.05),病理学损伤减轻.与C组比较,OGD组和BBG组T2-4时海马神经元突触体Glu和GABA的释放量增加(P＜0.05);与OGD组比较,BBG组T2-4时海马神经元突触体GABA释放量差异无统计学意义(P＞0.05),Glu释放量增加(P＜0.05).结论 P2X7受体介导了大鼠海马OGD时Glu和GABA的释放,其中胶质细胞上的P2X7起主导作用.     

缬沙坦对高糖上调系膜细胞细胞外调节蛋白激酶表达的影响

目的观察在高糖刺激下，系膜细胞细胞外调节蛋白激酶（ERKI／2）的活性变化以及缬沙坦对其影响，探讨缬沙坦保护肾脏作用的可能机制。方法原代培养大鼠肾脏系膜细胞，随机分为4组：低糖组（NG，d-葡萄糖5．5mmol／L）、高糖组（HG，d-葡萄糖30mmol／L）、甘露醇组（MG，d-葡萄糖5．5mmol／L＋甘露醇24．5mmol／L）和缬沙坦组（HG＋Val，d-葡萄糖30mmol／L＋缬沙坦10μmol／L）。用免疫细胞化学法及Western印迹法对系膜细胞中磷酸化ERK1／2（p-ERK1／2）的表达进行定位及半定量分析；RT—PCR法检测细胞中TGF-β1 mRNA的表达；放射免疫法测定各组细胞上清中Ⅳ型胶原的含量。结果高糖组系膜细胞中P-ERK1／2蛋白的表达较低糖组明显增高，并由胞质向胞核内转移，呈时间依赖方式（P〈0．01）；TGF-β1 mRNA及细胞上清液中Ⅳ型胶原水平均高于低糖组（P〈0．01）。而缬沙坦组上述指标均较同时相点高糖组显著降低，差异有统计学意义（P〈0．01）。甘露醇组与低糖组各指标间差异均无统计学意义。结论高糖可显著激活系膜细胞ERK信号通路，缬沙坦可抑制高糖的激活作用。     

皮质酮复合异丙酚对大鼠海马 CA1区长时程抑制的影响

目的探讨皮质酮复合异丙酚对大鼠海马CA1区锥体神经元产生的长时程抑制(LTD)的影响。方法制备Wistar大鼠400μm厚度的海马脑片,随机分为5组:对照组、脂肪乳剂组、异丙酚组、皮质酮组、皮质酮 异丙酚组。对照组不加任何药物,脂肪乳剂组、异丙酚组、皮质酮组、皮质酮 异丙酚组分别以100μmol/L脂肪乳剂、100μmol／L异丙酚、10μmol／L皮质酮、10μmol／L皮质酮复合100μmol／L异丙酚预孵脑片60min,然后给予低频刺激(LFS),记录LTD的表达情况。结果各组海马CAI区锥体神经元给予LFS后,都产生LTD,与对照组相比,脂肪乳剂组给予LPS后10-40minEPSC值没有明显变化,异丙酚组、皮质酮组和皮质酮 异丙酚组给予LPS后10-40min的EPSC值明显降低(P<0.05),且皮质酮 异丙酚组给予LPS后10-40min兴奋性突触后电流与异丙酚组和皮质酮组相比,差异有统计学意义(P<0.05)。结论100μmol／L异丙酚或10μmol/L皮质酮都使大鼠海马CA1区锥体神经元LTD表达易化,二药复合应用时则进一步增强LTD的表达。     

ERK1/2信号转导通路在七氟醚后处理减轻大鼠海马脑片缺氧无糖损伤中的作用

目的 评价细胞外信号调节激酶1/2(ERK1/2)信号转导通路在七氟醚后处理减轻大鼠海马脑片缺氧无糖损伤中的作用.方法 选取符合标准的大鼠海马脑片,采用随机数字表法,将其随机分为5组(n=10):缺氧无糖组(OGD组)海马脑片进行15 min缺氧无糖处理,即将灌流液改为经95％N2-5％ CO2混合气体饱和的无糖人工脑脊液(aCSF);4％七氟醚后处理组(Sevo组)缺氧无糖处理后用4％七氟醚平衡后的aCSF灌流30 min;ERK1/2特异性抑制剂PD98059组(PD组)缺氧无糖处理后用含ERK1/2特异性抑制剂PD98059(50 μmol/L)的aCSF灌流10 min;二甲基亚砜组(DMSO组)缺氧无糖处理后用含1 mol/L DMSO的aCSF灌流10 min;4％七氟醚后处理+PD98059组(SPD组)缺氧无糖处理后用含ERK1/2特异性抑制剂PD98059(50μmol/L)并通人4％七氟醚的aCSF灌流30 min,处理完成 后各组均再用正常aCSF灌流1h.采用脑片灌流及电生理技术,细胞外记录海马CAI区的顺向群峰电位(OPS);采用TTC染色-定量比色法评价海马脑片损伤程度.结果 与OGD组比较,Sevo组OPS恢复程度和恢复率升高,海马脑片损伤程度降低(P＜ 0.01),其余3组各指标差异无统计学意义(P＞0.05);与Sevo组比较,PD组、DMSO组和SPD组OPS恢复程度和恢复率降低,海马脑片损伤程度升高(P＜0.01).结论 ERK1/2信号转导通路参与了七氟醚后处理减轻大鼠海马脑片缺氧无糖损伤的过程.     

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.     

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.     

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.     

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.