绞股蓝总皂苷防治单侧输尿管结扎大鼠肾间质纤维化的实验研究

目的探讨绞股蓝总皂苷(GPs)对单侧输尿管结扎(UUO)大鼠肾组织结缔组织生长因子(CTGF)表达及肾间质纤维化的影响。方法采用UUO大鼠模型,将大鼠随机分为3组假手术组、模型组、GPs组。假手术组和模型组仅给予标准饲料30g,GPs组于术前3d至术后9d每天给予GPs200mg·kg-1·d-1灌胃,第9d处死各组大鼠。免疫组化法检测各组肾组织CTGF、转换生长因子β1(TGF-β1)和α-平滑肌肌动蛋白(α-SMA)的表达;RT-PCR方法检测各组CTGFmRNA含量;Masson染色评定各组肾小管间质损害程度。结果模型组CTGF、TGF-β1、α-SMA的表达及肾小管间质损伤指数明显高于假手术组(P<0.01),而GPs组各项指标明显低于模型组(P<0.01)。各项指标作相关分析,CTGF与肾小管间质损伤指数(r=0.788,P<0.01)、TGF-β1(r=0.879,P<0.01)、α-SMA(r=0.940,P<0.01)为正相关关系。结论绞股蓝总皂苷可以抑制肾纤维化时结缔组织生长因子表达,从而遏制肾纤维化的进展。     

结缔组织生长因子在关木通相关肾小管间质肾病肾间质纤维化中的作用

目的 通过观察关木通相关肾小管间质肾病(GMT-TIN)肾小管间质内纤维化相关生长因子表达及细胞外基质(ECM)沉积的特点,探讨其纤维化病变发生与发展的有关环节。方法 22例GMT-TIN患者根据病理特点分为急性组8例、慢性轻型组8例和慢性重型组6例,对其纤维化程度进行半定量分析。应用免疫组化SP法观察肾活检组织标本中,肾小管间质内α-平滑肌肌动蛋白(α-SMA)、纤连蛋白(FN)、IV型胶原、结缔组织生长因子(CTGF)和转化生长因子 β1(TGF-β1)的表达情况。分析上述指标之间以及与纤维化病变之间的相关关系。结果 (1)各组肾小管间质内均检测到高表达的α-SMA、FN和IV型胶原,随病变慢性化加重3者表达均明显增强,并与肾间质纤维化程度正相关(P<0.01)。(2)各组肾间质内均出现CTGF及TGF-β1表达,2者间显著正相关(r=O.771,P<0.0001),但在时相上存在一定差异。(3)肾间质内CTGF表达分别与FN及IV型胶原沉积正相关(r=0.6855和0.5964,P<0.01)、与纤维化病变程度正相关(r=0.4941,P<0.05)。结论(1)GMT-TIN肾间质内CTGF的高表达、CTGF与ECM沉积以及纤维化病变的相关性,提示其在GMT-TIN肾间质纤维化病变中起重要作用。(2)CTGF与TGF-β1的相关关系及2者表达时相的差异,进一步支持CTGF可能作为TGF-β1的下游效应因子在纤维化病变     

维甲酸抑制大鼠单侧输尿管梗阻模型肾间质纤维化

目的探讨维甲酸对大鼠单侧输尿管梗阻(UUO)模型肾间质纤维化的影响。方法建立大鼠UUO模型前2d治疗组和对照组分别每天给予10mg/kg全反式维甲酸或溶媒皮下注射。观察模型第3、7和12天肾小管损害百分比、肾间质纤维化程度、肾间质巨噬细胞数、肾间质α-平滑肌肌动蛋白(α-SMA)、胶原Ⅲ和单核细胞趋化蛋白-1(MCP-1)mRNA的表达。结果维甲酸显著减轻肾小管损害和肾间质纤维化(P<0.01)。治疗组肾间质巨噬细胞数和肾间质α-SMA表达显著低于对照组(P<0.01)。维甲酸显著抑制胶原Ⅲ和MCP-1mRNA表达(P<0.01)。结论维甲酸减少大鼠UUO模型肾间质巨噬细胞浸润、降低胶原Ⅲ和MCP-1mRNA表达、抑制α-SMA蛋白的表达,从而减轻肾间质纤维化。     

积雪草颗粒对UUO大鼠肾组织CTGF、α-SMA、HGF、MCP-1表达的影响

目的:探讨积雪草对单侧输尿管梗阻(UUO)大鼠肾组织结缔组织生长因子(CTGF)、α-肌动蛋白(α-SMA)、肝细胞生长因子(HGF)、单核细胞趋化蛋白(MCP-1)-1表达的影响,为临床上应用积雪草延缓肾衰竭提供依据。方法:50只雄性SD大鼠随机分为假手术组、模型组、积雪草大剂量组、积雪草小剂量组、对照(福辛普利)组。每组10只,除假手术组外均成功建立UUO大鼠模型,术后21 d腹主动脉采血,检测肝、肾功能的变化;免疫组化检测CTGF、α-SMA、HGF、MCP-1的表达部位及含量。结果:模型组CTGF、α-SMA、MCP-1的表达高于假手术组(P<0.01),药物干预组指标低于模型组(P<0.01);药物干预组HGF含量显著高于模型组(P<0.01);其中积雪草大剂量组的表达高于小剂量组(P<0.01),但与福辛普利组相似(P>0.05)。药物干预组BUN水平下降,Scr、ALT、AST变化不明显。结论:积雪草可通过上调UUO大鼠肾组织HGF的表达,抑制UUO大鼠肾组织CTGF、α-SMA、MCP-1表达而实现其抗肾小管间质纤维化(TIF)的作用,大剂量组与福辛普利组作用相似,且没有明显的肝肾毒性。     

结缔组织生长因子在肾活检组织中的表达及意义

目的 :检测不同间质纤维化程度的肾活检组织中结缔组织生长因子 (CTGF)和α -平滑肌肌动蛋白(α -SMA)的表达 ,观察CTGF、α -SMA与肾间质纤维化程度和肾功能之间的关系 ,探讨CTGF在肾脏肌成纤维细胞形成中可能的作用。方法 :选取不同病因和类型的肾活检标本 4 5例 ,按常规进行染色 ,根据光镜下小管间质的病变分组。采用免疫组化方法 ,检测各组标本CTGF和α -SMA的表达 ,并将CTGF的表达、α -SMA的表达、间质纤维化程度和患者血肌酐水平进行比较。结果 :CTGF主要表达于肾小管上皮细胞和一些肾间质细胞胞浆 ,并且随间质病变的加重 ,表达量增加 ,范围增大 ;α-SMA在病变肾间质区域表达增强 ,一些管腔破坏和萎缩的肾小管上皮细胞也可见表达 ,阳性分布区域与CTGF相似。肾小管间质中CTGF、α -SMA表达量之间呈正相关 ,CTGF和α -SMA表达量与肾间质纤维化病变程度和患者血肌酐水平均呈正相关关系。结论 :CTGF可能通过促进间质中肌成纤维细胞的形成而参与肾间质纤维化的形成 ,CTGF的表达上调对肾脏疾病有预后价值     

黄芪注射液改善肾间质纤维化的作用机制研究

目的:观察黄芪注射液对肾间质纤维化的改善作用并探讨其机制.方法:以单侧输尿管梗阻(unilateral ureteral obstruction,UUO)大鼠模型为研究对象.将36只SD大鼠随机分为对照组、UUO模型组和黄芪注射液治疗组.治疗组每日给予黄芪注射液(5 ml·kg-1·d-1)腹腔注射,术前1天始至术后第9天止.术后第10天取术侧肾脏组织.HE、PAS和苦味酸-天狼星红染色,观察肾小管间质病理改变、肾皮质相对间质容积和相对胶原含量的变化.免疫组织化学方法检测转化生长因子-β1(TGF-β1)、α-平滑肌肌动蛋白(α-SMA)和Ⅰ型胶原在肾间质中的表达.免疫印迹方法检测热休克蛋白47(heat shock protein 47,HSP47)在肾脏中的表达.结果:UUO大鼠模型组和治疗组均出现明显的肾间质纤维化病理改变,但治疗组病变程度相对较轻.肾皮质相对间质容积和相对胶原含量于模型组及治疗组明显高于对照组(P＜0.01),但治疗组明显低于模型组(P＜0.01).免疫组化染色显示:TGF-β1、α-SMA和Ⅰ型胶原表达于模型组和治疗组均明显高于对照组(P＜0.05),但治疗组较模型组有明显减少(P＜0.05).免疫印迹方法显示:HSP47蛋白表达于模型组和治疗组明显高于对照组(P＜0.05),但治疗组较模型组有明显减少(P＜0.05).结论:黄芪注射液对大鼠肾间质纤维化具有明显的改善作用,这种作用部分是通过抑制TGF-β1表达,阻止肾小管上皮细胞转分化,减少胶原合成实现的.     

慢性马兜铃酸肾病患者肾小管上皮细胞转分化的研究

目的探讨慢性马兜铃酸肾病。肾小管上皮细胞转分化与肾间质纤维化的关系。方法以慢性马兜铃酸肾病患者的肾组织为标本,作常规Masson染色化病理检查;用天狼星红组织化学(组化)染色检查胶原Ⅰ、Ⅲ表达;用免疫组化染色检查角蛋白(CK)、α-平滑肌肌动蛋白(α-SMA)、波形蛋白(Vim)及转化生长因子-β1(TGF-β1)表达。对结果进行定量或半定量分析。结果 肾间质Masson染色纤维化面积及胶原Ⅰ、Ⅲ面积,与肾小管间质α-SMA及Vim阳性表达面积呈显著正相关(P<0.05),与肾小管CK阳性表达面积呈显著负相关(P<0.05);病变过程中健存肾小管TGF-β1表达明显增强。结论慢性马兜铃酸肾病患者的肾小管上皮细胞可转分化为肌成纤维细胞,参与肾间质纤维化,而这细胞转分化很可能与其自身高表达TGF-β1相关。     

金属蛋白酶组织抑制剂1在大鼠肾小管间质损害中的表达及其意义

目的 观察单侧输尿管梗阻(UUO)大鼠模型中金属蛋白酶组织抑制剂1(TIMP-1)在肾小管间质中的表达部位、动态变化及其与肾小管问质损害的关系。方法 制备UUO大鼠模型,采用免疫组织化学方法检测UUO术后第1、3、5、7、14天肾小管间质中TIMP-1、α-平滑肌肌动蛋白(SMA)、增殖细胞核抗原(PCNA)和单核巨噬细胞抗原(ED)-1的表达及其与输尿管梗阻后肾小管间质损害的关系。结果 UUO术后第1天肾间质可见少量TIMP-1表达细胞,第3～7天TIMP-1表达明显增加,主要表达于肾小管上皮细胞和肾间质。UUO术后第3天肾小管PCNA表达达高峰,随后下降,而肾间质PCNA水平于第7～14天仍较高。UUO术后第3天肾间质成纤维细胞及肾小管上皮细胞可检出α-SMA表达并随时间递增。α-SMA阳性面积与肾间质相对面积成正相关(r=0.924,p<0.01)。TIMP-1表达与间质相对面积(r=0.835,P<0.05)及α-SMA阳性面积(r=0.922,P<0.01)成正相关。结论 TIMP-1蛋白质于肾小管间质病变早期表达于肾小管间质,早于肾间质纤维化出现,其表达量与肾间质α-SMA表达及肾间质相对面积呈正相关并随病变进展逐渐增加。TIMP-1在肾小管上皮细胞和问质细胞的高表达及肾小管上皮细胞和间质细胞增殖可能参与介导UUO术后肾小管间质损害。     

冬虫夏草在肾间质纤维化大鼠模型中的作用及其对TGF-β1、α-SMA的影响

目的：探讨冬虫夏草在肾小管间质纤维化大鼠模型中肾脏保护作用及其可能的作用机制。方法：采用单侧输尿管结扎术（UUO）致肾小管间质纤维化大鼠模型。将大鼠随机分为3组：假手术组、模型组、虫草治疗组。手术后第9d处死各组大鼠，用免疫组化半定量检测各组肾脏TGF-β1、α-SMA、Ⅳ型胶原的表达，Masson染色评定各组肾小管间质损害程度。结果：模型组TGF-β1、α-SMA、Ⅳ型胶原的表达及肾小管间质损伤指数明显高于假手术组（P〈0．01），而虫草治疗组明显低于模型组（P〈0．01）。结论：冬虫夏草可能通过下调TGF-β1，抑制肾小管上皮细胞、成纤维细胞转化为成肌纤维细胞防治。肾小管间质纤维化。     

毛蕊花糖苷改善单侧输尿管梗阻模型大鼠肾纤维化

该研究探讨毛蕊花糖苷对单侧输尿管梗阻模型大鼠肾纤维化的作用。采用随机数字表法将24只成年健康雄性SD大鼠随机分为假手术(CON)组、单侧输尿管梗阻(UUO)组、UUO+毛蕊花糖苷(ACT)组和UUO+贝那普利(BZ)组, 采用单侧输尿管结扎术建立肾纤维化动物模型。HE染色和Masson染色观察各组大鼠肾组织病理改变。免疫组化法检测肾组织Ⅲ型胶原蛋白(CollagenⅢ)、热休克蛋白(HSP)-47、结缔组织生长因子(CTGF)、α平滑肌肌动蛋白(α-SMA)、β联蛋白(β-catenin)、B细胞淋巴瘤因子2(Bcl-2)和半胱氨酸蛋白酶3(Caspase-3)蛋白的表达。Western印迹法检测肾组织葡萄糖调节蛋白(GRP)78蛋白表达。结果显示, 与CON组比较, UUO组大鼠肾小管扩张, 肾间质胶原纤维沉积显著增加;UUO+ACT组和UUO+BZ组大鼠肾小管扩张和间质胶原纤维沉积程度较UUO组显著减轻, 但仍明显重于CON组。与CON组比较, UUO组大鼠肾组织CTGF、α-SMA、CollagenⅢ、HSP-47、β-catenin及GRP78蛋白表达量均显著较高, Bcl-2...     

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.