莲子提取物对大鼠急性肾缺血再灌注损伤的影响研究

目的：研究莲子提取物对大鼠急性肾缺血再灌注损伤的影响,并初步探讨其作用机制,为将来应用于临床提供理论依据。方法：选用健康雄性SD大鼠30只随机分为三组：假手术组（ Sham组）、缺血再灌注损伤组（ RIRI组）、莲子提取物给药组（ LE组）。再灌注24 h 后,检测大鼠血清中丙二醛（ MDA ）、超氧化物歧化酶（ SOD ）、血清肌酐（ Scr ）和尿素氮（ BUN）,肾组织中MDA含量和谷胱甘肽过氧化物酶（ GSH-Px）的活性,并采用肉眼和光镜下观察肾脏组织病理学切片以及肾小管计分等病理变化。结果：与肾脏缺血再灌注组相比,莲子提取物给药组大鼠血清中MDA、 Scr、 BUN含量均显著降低（P〈0.01）,血清中SOD含量升高（P〈0.01）、肾小管计分明显降低（P〈0.01）,肾组织中MDA含量降低（P〈0.01）、GSH-Px活性增强（P〈0.01）。结论：莲子提取物对急性肾缺血再灌注损伤具有保护作用,其作用机制可能与抗自由基损伤和减轻脂质过氧化、抗血栓形成有关。     

缺血后处理对大鼠肾缺血再灌注损伤的影响

目的探讨缺血后处理对大鼠肾缺血再灌注（I／R）损伤的影响及其机制。方法18只雄性SD大鼠随机分为3组（n=6）：假手术组（S组）、缺血再灌注组（I／R组）和缺血后处理组（IPo组）。采用夹闭双侧肾蒂45min-再灌注6h制备肾脏缺血再灌注损伤模型。IPo组在夹闭双侧肾蒂45min后，再灌注10s，缺血10s，重复3次后，完全恢复肾血流。再灌注6h时开胸，取心脏血后处死大鼠，取肾组织。测定血清肌酐（Cr）、尿素氮（BUN）和尿酸（UA）浓度，肾组织中丙二醛（MDA）含量和超氧化物歧化酶（SOD）活性；光镜下观察肾组织病理学改变；采用原位末端脱氧核苷酸转移酶标记（TUNEL）法检测肾组织中凋亡细胞，光镜下计数凋亡细胞，并计算肾小管上皮细胞凋亡指数（AI）。结果与S组比较，I／R组和IPo组Cr和BUN浓度升高（P〈0．05），UA浓度差异无统计学意义（P〉0．05），肾组织SOD活性降低，MDA含量升高，肾小管上皮细胞凋亡指数增加（P〈0．05），病理损伤明显。与I／R组比较，IPo组Cr和BUN浓度降低（P〈0．05），UA浓度差异无统计学意义（P〉0．05），SOD活性升高，MDA含量降低，肾小管上皮细胞凋亡指数减少（P〈0．05），病理损伤减轻。结论缺血后处理能减轻大鼠肾缺血再灌注损伤，其机制与增强肾脏抗氧化能力和抑制肾组织细胞凋亡有关。     

红景天甙对大鼠肾脏缺血再灌注损伤的保护作用

目的探讨红景天甙对大鼠肾脏缺血再灌注损伤（IRI）的预防和保护作用。方法将32只健康成年SD大鼠随机分成正常对照组、假手术组、缺血再灌注组和红景天甙组4组，每组8只。缺血再灌注组和红景天甙组分别制作肾脏缺血再灌注模型，红景天甙组予以红景天甙预处理。检测血中尿素氮（BUN）和肌酐（Scr）及肾脏中超氧化物歧化酶（SOD）、丙二酰二醛（MDA）和钠钾ATP酶（Na^＋-K^＋ATPase）含量，并用光镜和电镜观察肾脏组织形态学变化。结果红景天甙组血清BUN和Scr水平、肾皮质MDA含量较缺血再灌注组显著降低（P〈0．01），而肾皮质中SOD和Na^＋-K^＋ATPase含量与缺血再灌注组相比显著升高（P〈0．01）；肾组织光镜和电镜观察均见缺血再灌注组肾小球和肾小管上皮细胞损伤明显，而红景天甙组肾小球及肾小管仅见轻微损伤。结论红景天甙能有效降低大鼠肾脏缺血再灌注损伤（IRI），对肾脏IRI有明显的预防和保护作用，为临床上肾脏IRI提供新的预防和治疗思路。     

甘氨酸对肾缺血-再灌注损伤的保护作用及对iNOS表达的影响

目的探讨甘氨酸对急性肾缺血-再灌注损伤的保护作用及作用机制。方法将24只Wistar大鼠随机分为假手术组（A组）、对照组（B组）、甘氨酸治疗组（C组），通过夹闭大鼠双侧肾蒂30min，再灌注30min制成肾缺血-再灌注损伤动物模型，检测尿量、血尿素氮（BUN）、血肌酐（Cr），肾组织光镜及电镜检查并使用免疫组化法检测iNOS表达。结果B组比A组尿量增加，血BUN、Cr升高，肾小管上皮细胞变性坏死明显，iNOS表达明显增强（P〈0．05）。C组比B组尿量明显增加，血BUN、Cr明显下降，肾小管上皮细胞变性坏死程度减轻，iNOS表达明显减少（P〈0．05）。结论甘氨酸对大鼠肾脏缺血-再灌注损伤有明显的保护作用，其机制可能与抑制大鼠缺血-再灌注后肾脏iNOS蛋白表达有关。     

臭氧氧化预处理对大鼠肾缺血再灌注损伤的热休克蛋白表达的影响

目的 探讨臭氧氧化预处理通过诱导热休克蛋白70(HSP70)的合成,保护大鼠肾脏缺血再灌注损伤的作用与机制.方法 建立原位大鼠单侧肾缺血再灌注动物模型,I/R前15 d经直肠吹入氧气和臭氧的混合气体5.0～5.5 ml(臭氧浓度50 mg/L,1 mg/kg体蕈,每日 1次).全自动生化分析仪检测尿素氮(BUN)、肌酐(Cr),比色法测定血清的脂质过氧化产物丙二醛(MDA)、超氧化物歧化酶(SOD).Western blot检测HSP70蛋白的含量;逆转录聚合酶链反应(RT-PCR)方法检测HSP70的表达.结果 肾缺血再灌注24 h后,血清中BUN、Cr、MDA明显增高,肾组织内HSPT0表达明显增强(P<0.05),经臭氧氧化预处理后,血清中的BUN、Cr、MDA均降低,SOD升高;HSP70表达升高更加明显(P<0.05).结论 臭氧氧化预处理可以诱导大鼠肾缺血再灌注组织中HSP70表达,减轻大鼠肾脏缺血再灌注损伤.     

环加氧酶抑制剂对缺血再灌注大鼠肾脏的保护作用

目的：本实验研究了环加氧酶抑制剂对缺血再灌注损伤（ischemia/reperfusion injury,I/R）所致大鼠肾脏组织细胞凋亡、Bcl-2蛋白和超氧化歧化酶（SOD）、丙二醛（MDA）表达的影响。方法：将36只大鼠随机分为3组：对照组,I/R模型组,罗非昔步治疗组,每组12只。I/R大鼠模型采取夹闭双侧肾动脉60min,恢复再灌注24h的方法建立。对照组大鼠除不钳夹双侧肾蒂外,余步骤与手术组同。观察肾组织病理改变,检测肾组织中Bcl-2蛋白、SOD和MDA含量的表达,TUNEL法检测细胞凋亡水平。结果：组织学检查发现对照组肾小管排列整齐,间质无充血水肿,I/R组可见明显损害,肾小管上皮细胞肿胀变性,肾小管扩张,可见管型和坏死脱落细胞,间质充血水肿,炎细胞浸润。治疗组组织损伤较I/R组明显减轻。免疫组化结果半定量分析显示模型组Bcl-2蛋白明显增多,给药组Bcl-2的水平较模型组明显减低（P〈0.05）。模型组细胞凋亡明显增多,给药组细胞凋亡水平较模型组明显减低（P〈0.05）。模型组肾组织SOD的活性明显降低,MDA含量增高,给药组比模型组有所改善。结论：罗非昔步能抑制I/R肾脏组织Bcl-2蛋白的表达,减轻细胞凋亡,抑制脂质过氧化产物MDA的产生,并提高抗氧化酶SOD的活性,减轻肾脏缺血再灌注损伤。     

缺血后处理对肾缺血再灌注损伤的抑制作用及对细胞凋亡的影响

目的 观察缺血后处理对大鼠急性.肾缺血再灌注损伤的抑制作用及其对细胞凋亡的影响.方法 建立原位大鼠单侧肾缺血再灌注动物模型,摘除右肾后对左肾行缺血后处理,即10 s再灌注,10 s缺血,6次循环后再灌注24 h.全自动生化分析仪检测血尿素氮(BUN)和肌酐(Cr)含量,比色法测定血浆中脂质过氧化产物丙二醛(MDA)和超氧化物歧化酶(SOD)含量,免疫组织化学法观察肾组织中细胞色素C的表达,流式细胞术检测细胞凋亡率,免疫印迹法(Western blot)检测胞浆中细胞色素C的含量.结果 肾缺血再灌注24 h后,血中BUN、Cr和MDA明显增高,肾细胞凋亡率明显增加.移植肾经缺血后处理,血中BUN、Cr和MDA含量均降低,SOD含量升高,细胞色素C释放减少,肾细胞凋亡率明显降低.结论 缺血后处理可以减轻移植肾脂质过氧化反应,减少肾细胞凋亡率,减轻肾缺血再灌注损伤.     

大鼠肾缺血-再灌注后JNK mRNA及蛋白表达的变化及银杏达莫注射液的干预作用

目的：观察JNK在肾缺血-再灌注损伤大鼠肾组织中的表达,研究银杏达莫注射液对肾缺血-再灌注损伤的防治作用。方法：将健康雄性SD大鼠50只随机分为5组：假手术对照组（n=10）,缺血-再灌注损伤模型组（n=10）,银杏达莫高剂量、中剂量、低剂量组（每组10只）。对于模型组、高、中、低剂量组,切除右肾,夹闭左侧肾蒂缺血1h,移去动脉夹再灌注1h,除此之外,对于银杏达莫处理组,手术前分别按每天0.9,1.8,3.6ml/kg的剂量尾静脉注射给药1周,假手术对照组和模型组手术前按每天1.8ml/kg的剂量尾静脉注射生理盐水,给药1周。检测肾组织丙二醛（MDA）含量、超氧化物歧化酶（SOD）的活性及血肌酐（Scr）、血尿素氮（BUN）的含量。取肾组织光镜、电镜下观察各组肾组织的形态学变化,用RT-PCR技术检测各组大鼠肾组织JNKmRNA的表达情况,Western印迹法观察p38MAPK、JNK的活化情况。结果：与假手术对照组相比,模型组大鼠Scr（214.2±40.1）μmol/L、BUN（8.75±1.28）mmol/L及MDA（11.27±2.43）nmol/mgprot含量均比假手术组增高（P〈0.01）,SOD（103.62±6.59）nmol/mgprot活性显著下降（P〈0.01）;肾组织JNKmRNA（1.38±1.36）水平显著升高（P〈0.01）;肾组织p-JNK蛋白水平显著上升,与模型组比较差异有统计学意义（P〈0.05）。银杏达莫注射液干预后,Scr、BUN及MDA含量显著降低,SOD活性显著升高;肾组织JNKmRNA水平显著下调,与模型组比较差异有统计学意义（P〈0.01）;肾组织p-JNK蛋白水平显著下调,与模型组比较差异有统计学意义（P〈0.05）;银杏达莫不同剂量组之间差异无统计学意义。结论：银杏达莫注射液可通过降低氧自由基水平、减轻脂质过氧化反应,从而下调JNKmRNA及蛋白表达水平以改善缺血-再灌注损伤大鼠肾功能,减轻其损伤程度。     

丁羟茴香醚对衰老大鼠肾脏缺血再灌注损伤的保护作用

目的观察老年大鼠肾脏缺血再灌注（I／R）模型中。肾小管上皮细胞的损伤变化，探讨活性氧（ROS）清除剂对I／R损伤的保护作用。方法27月龄大鼠随机分为假手术组、I／R模型组、丁羟茴香醚（BHA）组和nicardipine组。夹闭双侧。肾动脉30min再灌注18h制成I／R模型。观察肾功能、肾脏病理改变、肾小管上皮细胞凋亡情况。检测肾组织半胱氨酸天冬氨酸蛋白酶（caspase）3、细胞色素C表达。测定肾组织脂质过氧化物丙二醛（MDA）含量和超氧化物歧化酶（SOD）活性。结果（1）肾脏I／R损伤时，老年大鼠肾功能明显减退，肾组织病理改变比较明显，大量肾小管上皮细胞凋亡，肾组织caspase-3、细胞色素C表达明显上调。肾组织中MDA增加、SOD活性下降（P均〈0．05）。（2）BHA或nicardipine均能明显改善肾功能。肾组织病理改变和凋亡相关指标（P〈0．05）；BHA或nicardipine均能减少组织中MDA含量，部分恢复肾组织中SOD含量。结论老年大鼠肾脏I／R损伤时肾小管上皮细胞凋亡增加，肾功能减退。ROS堆积后，线粒体损伤导致肾小管上皮细胞凋亡。清除ROS可以抑制‘肾小管上皮细胞凋亡，减轻I／R损伤。     

臭氧氧化预处理对大鼠肾缺血再灌注损伤的热休克蛋白表达的影响

目的 探讨臭氧氧化预处理通过诱导热休克蛋白70(HSP70)的合成,保护大鼠肾脏缺血再灌注损伤的作用与机制.方法 建立原位大鼠单侧肾缺血再灌注动物模型,I/R前15 d经直肠吹人氧气和臭氧的混合气体5.0～5.5 ml(臭氧浓度50 mg/L,1 mg/kg体重,每日1次).全自动生化分析仪检测尿素氮(BUN)、肌酐(Cr),比色法测定血清的脂质过氧化产物丙二醛(MDA)、超氧化物歧化酶(SOD).Western blot检测HSP70蛋白的含量;逆转录-聚合酶链反应(RT-PCR)方法检测HSPT0的表达.结果 肾缺血再灌注24 h后,血清中BUN、Cr、MDA明显增高,肾组织内HSP70表达明显增强(P＜0.05),经臭氧氧化预处理后,血清中的BUN、Cr、MDA均降低,SOD升高;HSP70表达升高更加明显(P＜0.05).结论 臭氧氧化预处理可以诱导大鼠肾缺血再灌注组织中HSP70表达,减轻大鼠肾脏缺血再灌注损伤.     

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.     

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.     

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.     

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.