rhGDNF对大鼠脊髓损伤后Ntyr表达影响的研究

目的研究大鼠脊髓损伤（spinal cord injury,SCI）后应用人重组胶质细胞源性神经营养因子（recombinated human glial cell line derived neurotrophic factor,rhGDNF）对酪氨酸硝基化蛋白（nitrotyrosine,Ntyr）表达情况的影响。方法48只雄性SD大鼠随机分为正常组、假手术组、生理盐水对照组和rhGDNF实验组,改良Allen法致脊髓中等程度损伤,伤后1d、3d、7d、14d用免疫荧光染色法测定Ntyr的表达情况,同时评定下肢运动功能（Tarlov评分和改良Rivlin斜板）。结果伤后1d rhGDNF组Ntyr阳性神经元数量多于生理盐水对照组（P〈0．05）,伤后3d、7d、14d时较同时程生理盐水对照组明显减少（P〈0．05）。2组的运动功能评分比较：伤后1d无明显差异,伤后3d、7d、14d时rhGDNF治疗组较生理盐水对照组明显提高（P〈0．05）。结论SCI后应用rhGDNF可减少大鼠脊髓Ntyr的表达,促进其运动功能恢复。     

17β-雌二醇对大鼠脊髓损伤后神经保护作用的研究

目的：探讨17β-雌二醇（E2）对大鼠脊髓损伤（SCI）后的神经保护作用及其机制。方法：应用改良的Allen′s重物打击法建立大鼠急性脊髓损伤模型,将大鼠随机分为两组：A组（PBS对照组）和B组（E2治疗组）,每组42只,B组造模成功后15min及24h腹腔注射E2（4.0mg/kg,以PBS溶解）,A组在相同时间给予等量无菌PBS。分别于伤后7d、14d、21d及28d,应用改良Tarlov评分法和Rivlin斜板试验评价大鼠脊髓神经功能恢复情况。于伤后6h、24h、3d、7d、14d及28d时处死动物,以损伤部位为中心取材,HE染色观察脊髓组织病理变化,TUNEL法染色检测细胞凋亡,免疫组化染色检测caspase-3、Bcl-2的表达情况。结果：从伤后14d起,B组Tarlov评分和斜板试验角度与A组相比差异有显著性（P〈0.01）。TUNEL法检测表明,大鼠SCI后存在细胞凋亡,3d时达高峰,与caspase-3的表达基本一致,B组伤后24h、3d及7d时凋亡细胞比率显著低于A组（P〈0.01或P〈0.05）。免疫组化结果显示B组伤后24h、3d、7d、14d及28d时caspase-3表达低于A组（P〈0.01或P〈0.05）,而Bcl-2表达高于A组（P〈0.01或P〈0.05）。结论：E2能促进大鼠SCI后的神经功能恢复,具有一定的神经保护作用;E2可能是通过减少SCI后继发性细胞凋亡的机制发挥作用的。     

人胚神经干细胞移植治疗大鼠脊髓损伤

目的 探讨人胚神经干细胞（hNSC）移植治疗脊髓损伤（SCI）的可行性。方法 分离、培养和鉴定hNSC；用5溴-2脱氧尿苷嘧啶（BrdU）标记hNSC，并将其移植到14只T10半横断的Wistar大鼠损伤脊髓内（另外14只T10半横断损伤的大鼠作为对照组，仅损伤脊髓内注射DMEM／F12培养液），用BrdU的FITC免疫荧光染色检测移植细胞的存活和迁徙，用NF-200、GFAP免疫组织化学鉴定移植细胞的分化，BBB评分评定大鼠功能恢复情况。结果 （1）获得了大量的hNSC；（2）用免疫组织化学可以检测到移植的hNSC能在体内长时间存活（达2个月）并向远处迁徙，并分化为神经元和胶质细胞；（3）检测到实验组大鼠BBB得分明显高于对照组大鼠（P〈0．01），在SCI后第10周时实验组和对照组BBB得分最大差距达到2．1分。结论 hNSC移植能促进SCI大鼠后肢功能恢复，它是SCI移植治疗较有价值的细胞资源。     

不同靶点注射骨髓基质干细胞对大鼠脊髓损伤修复的影响

目的研究不同靶点注射骨髓基质干细胞（BMSCs）对脊髓损伤（SCI）修复的影响,观察注射的BMSCs在SCI局部和两侧健康组织中的存活情况。方法体外分离培养BMSCs并鉴定。采用改良Allen打击法制作sD大鼠SCI（T10节段）模型,伤后9d注射细胞,将100只sD大鼠随机分为5组（每组20只）：4点法治疗组（脊髓损伤区头、尾侧）;6点法治疗组（加上脊髓损伤中心区）：8点法治疗组（加损伤区及损伤区头尾的上或下节段）;10点法治疗组（加损伤区及损伤区头尾的上和下节段）;E组为空白对照组,未注射细胞。通过改良的BBB评分,评估不同靶点注射BMSCs对SCI运动功能恢复的促进作用。通过组织切片和HE染色观察注射细胞在SCI局部和两侧健康组织中的存活情况。结果成功培养BMSCs并鉴定。改良的BBB评分显示,局部注射BMSCs能明显的促进SCI动物的运动功能的恢复（P〈0．01）。6、8、10点法注射明显优于4点法（P〈0．01）。6、8、10点法之间差异无统计学意义（P〉0．05）。组织切片观察显示,6点法注射的BMSCs在SCI局部和两侧健康组织中的存活比例明显优于4点法（P〈0．01）,6、8、10点法之间差异无统计学意义（P〉0．05）。结论6点法注射能有效的促进SCI动物的运动功能的恢复,同时能减少过多次数的注射对健康脊髓的损伤。注射的BMSCs在SCI局部和两侧健康组织中的存活较好。     

大鼠胸段脊髓损伤后后肢运动功能不同评价标准的比较研究

目的：对大鼠脊髓损伤模型运动功能不同评价方法进行评价。方法：大鼠急性脊髓压迫损伤模型按轻、中、重度损伤随机分组,分别应用叙板试验、Tarlov评分和BBB（Basso,Beattie and Bresnahan,BBB)评分法进行后肢运动功能评价。结果：三种方法评价结果均与损伤程度相关,其中BBB评分相关性最高,并且体现了损伤后运动功能恢复的每一阶段。结论：BBB评分对SCI模型运动功能评价具有明显优势,可做为今后研究的标准评分法。     

补阳还五汤对脊髓损伤大鼠脊髓组织病理学的影响

目的：探讨补阳还五汤对脊髓损伤（SCI）大鼠脊髓组织病理学结构的影响。方法：SPF级Wistar大鼠制作中度SCI模型,参照改良Tarlov评分标准分为模型组、补阳还五汤组、金纳多组、正常组;2周后取SCI大鼠脊髓组织HE染色制片,进行病理组织学观察。结果：模型组出现脊髓组织出血、组织疏松、水肿,细胞胞浆外渗、变性,呈空泡状,神经元细胞核游离、固缩等严重损伤现象;补阳还五汤组和金纳多组上述变化均有不同程度的恢复,其中以空泡变性减轻,神经细胞形态恢复,细胞核分布排列趋于完整尤为明显,与模型组比较改善明显;脊髓组织修复趋势补阳还五汤组＞金纳多组＞模型组。Tarlov评分比较,在0～3周内,补阳还五汤组与金纳多组评分随时间变化差异无统计学意义（P＞0.05）,与模型组及正常组比较差异有统计学意义（P＜0.05）;各时间点组间比较结果：造模后3 d,模型组大鼠评分显著降低,与正常组比较差异有显著性统计学意义（P＜0.01）;补阳还五汤组大鼠后肢运动功能恢复明显,与模型组同时间点比较差异有统计学意义（P＜0.05）。结论：补阳还五汤能有效改善SCI损伤大鼠脊髓组织的组织结构损伤,营养神经元细胞,促进神经纤维的修复。     

表没食子儿茶素没食子酸酯对大鼠脊髓损伤后神经功能恢复的影响

【摘要】 目的：研究经蛛网膜下腔给予表没食子儿茶素没食子酸酯（epigallocatechin gallate,EGCG）对大鼠脊髓损伤（spinal cord injury,SCI）后神经功能恢复的影响及其作用机制。方法：成年雌性SD大鼠40只,随机分为4组,每组10只,假手术组（A组）仅切除椎板;对照组（B组）SCI后,蛛网膜下腔注射同体积载体溶液;10mg/kg EGCG治疗组（C组）SCI后经蛛网膜下腔注射EGCG 10mg/kg;20mg/kg EGCG治疗组（D组）SCI后经蛛网膜下腔注射EGCG 20mg/kg。改良Allen法（40g·cm）制作T10节段SCI模型,L4水平蛛网膜下腔注射EGCG或载体溶液。术前、术后1d、术后3d及术后1、2、3、4周进行盲法BBB评分、斜板试验;术后4周时处死大鼠,病理学检查（Luxol fast blue染色）观察脊髓损伤部位残余髓鞘情况;免疫组化及Western blot法检测胶质细胞源性营养因子（GDNF）、脑源性神经营养因子（BDNF）、Bcl-2和Bax的表达水平。结果：A组术前及术后各时间点BBB评分均为21分,斜板试验角度无明显变化;术后各时间点B、C组和D组BBB评分及斜板试验角度均小于A组（P＜0.05）;术后1d、3d时,B、C组和D组BBB评分以及斜板试验角度无统计学差异（P＞0.05）;术后1、2、3、4周时,C、D组的BBB评分及斜板试验角度均大于B组（P＜0.05）,C组的BBB评分及斜板试验角度与D组比较均无统计学差异（P＞0.05）。术后4周时,B、C、D组大鼠脊髓损伤部位的髓鞘残余面积均小于A组（P＜0.05）,C、D组明显大于B组（P＜0.05）,在损伤脊髓中心D组明显大于C组（P＜0.05）。术后4周时免疫组化检查,B、C、D组的BDNF、GDNF、Bcl-2和Bax的阳性表达强于A组,C、D组的BDNF、GDNF和Bcl-2的阳性表达强于B组,Bax的阳性表达弱于B组。术后4周时Western blot法检测,B、C、D组的BDNF、GDNF、Bcl-2和Bax的表达高于A组（P＜0.05）;C、D组的BDNF和GDNF表达明显高于B组（P＜0.05）,C组与D组无统计学差异（P＞0.05）;C、D组的Bcl-2表达明显高于B组（P＜0.05）,C组与D组比较无统计学差异（P＞0.05）;C组和D组的Bax表达明显低于B组（P＜0.05）,D组明显低于C组（P＜0.05）。结论：EGCG可有效促进大鼠SCI后的神经功能恢复,其机理可能与髓鞘的丢失减少、神经营养因子BDNF和GDNF的表达上调及细胞凋亡被抑制等有关。     

骨髓间充质干细胞移植对大鼠脊髓损伤后氧化应激的影响

目的研究骨髓间充质干细胞（bone marrow mesenchymal stem cells,BMSCs）移植对大鼠脊髓损伤（spinal cord injury,SCI）后氧化应激的影响。方法取大鼠股骨和胫骨骨髓培养BMSCs并传代。参照Taoka方法制作30只大鼠脊髓压迫损伤模型,随机分为3组,损伤组（SCI）、假移植组（SCI＋生理盐水）、移植组（SCI＋BMSCs）。脊髓损伤30 min时,假移植组和移植组于损伤周围相应注射生理盐水和BMSCs。在损伤后第3天、7天、14天和28天,进行BBB（Basso-Beattie-Bresnahan,BBB）行为学评价。应用MTT方法检测血清中超氧化物岐化酶（SOD）活性和丙二醛（MDA）水平。结果脊髓损伤后,BMSCs移植第14天即可观察到大鼠后肢运动功能明显改善,第28天BBB评分有明显提高。与损伤组和假移植组大鼠相比,第7天、14天和28天移植组血中MDA水平降低（P〈0.05）;血中SOD水平较高（P〈0.05）。结论 BMSCs移植对SCI神经功能恢复有促进作用,其机制可能与其抑制氧化应激有关。     

大鼠脊髓损伤后不同行为学评分方法的比较研究

[目的]探讨胸段脊髓损伤后神经功能评价的最佳方法。[方法]将20只SD成熟雌性大鼠随机分为脊髓损伤组、假手术组。脊髓损伤组采用T10脊髓离断法制作脊髓损伤模型,假手术组仅行椎板切除术。分别于术后1、3、5、7、14、21、28 d观察大鼠后肢神经功能恢复的情况并记录结果。评价标准分别为:改良Tarlov评分和BBB评分。[结果]两组大鼠改良Tarlov评分和BBB评分值在伤后各时间点差异均非常显著(P﹤0.01);评分值标准化为百分制后,假手术组大鼠两种评分值之间的一致性较好,脊髓损伤组大鼠两种评分值之间的差异较大,伤后1、3、5、7d时差异非常显著(P﹤0.01)。[结论]两种不同行为学评分方法的评价结果均与损伤程度相关,其中BBB评分相关性较高,其对脊髓损伤模型运动功能评价具有明显优势,能准确、客观地反映大鼠胸段脊髓损伤后运动功能恢复的每一阶段,可作为今后研究的标准评分法。     

骨髓间充质干细胞经蛛网膜下腔移植治疗大鼠脊髓损伤及其对T细胞亚群影响的研究

目的将异体骨髓间充质干细胞（marrow mesenchymal stem cells,MSCs）移植至脊髓损伤（spinalcord injury,SCI）大鼠蛛网膜下腔,探讨其治疗效果以及对T细胞亚群的影响。方法取6周龄SD大鼠10只,采用密度梯度离心法进行细胞分离及培养,传至第6代后收集细胞。雌性8周龄SD大鼠60只,采用重物打击法制备SCI模型,从BBB后肢功能评分为0的存活大鼠随机取40只分为两组,每组20只。实验组（A组）：经蛛网膜下腔注入经BrdU标记的细胞浓度为2×106/ml的MSCs细胞悬液1ml;对照组（B组）：注入等量L-DMEM。另取20只正常雌性8周龄SD大鼠作为空白组（C组）。于第1、2和3周行BBB后肢功能评分,并采外周血经流式细胞仪检测T细胞亚群;第3周时,A、B组大鼠取损伤处脊髓,行组织切片观察。结果A组BBB后肢功能评分第3周优于B组,但仍低于C组,差异均有统计学意义（P〈0.05）;CD4＋T细胞在第1、2和3周均较B、C组少,CD8＋T细胞在第2、3周较B、C组少,CD4＋/CD8＋T细胞比值在第1周较B、C组少,上述差异均有统计学意义（P〈0.05）;但CD4＋/CD8＋T细胞比值在第2、3周与B、C组比较差异无统计学意义（P〉0.05）。组织学观察,A组第3周脊髓损伤处空泡缩小,有组织长入,较B组有轻微改善,但未明确见到BrdU阳性标记的MSCs。结论MSCs经蛛网膜下腔移植对SCI有一定治疗作用,且在一定时间内不引起机体排斥反应,在第1周对T细胞亚群的抑制更为明显,为临床利用MSCs治疗SCI及其他疾病提供了免疫学实验依据。     

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.     

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.     

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.