重组大鼠肝再生增强因子对急性肾衰竭大鼠肾脏的保护作用

目的 探讨重组大鼠肝再生增强因子(rrALR)对庆大霉素所致急性肾衰竭（ARF）大鼠肾小管上皮细胞及肾功能的保护作用。 方法 雌性Wistar大鼠150只，随机分成5组，每组30只，即健康对照组，ARF模型组，模型+空质粒对照组（空质粒组），模型+rrALR干预组（ALR组）：根据给予rrALR的剂量不同分为ALR1组和ALR2组两个亚组。分别于实验的第4、8、12、16和21天每组随机抽取6只大鼠在留取血、尿标本后，处死大鼠并取肾组织标本。常规生化方法检测各组大鼠BUN、Scr和尿N-乙酰-β-D-葡萄糖苷酶（NAG）酶的变化；PAS染色观察各组大鼠肾组织病理学改变；免疫组化法检测大鼠肾组织中ALR和增殖细胞核抗原（PCNA）的表达；Western印迹法检测肾组织中ALR蛋白的表达量。 结果 ARF大鼠各组BUN、Scr及尿NAG酶水平在第4、8、12、16天时均较对照组显著升高（P < 0.05）。与模型组和空质粒组相比，ALR组BUN、Scr及尿NAG酶水平明显降低（P < 0.05）；肾组织病理损害程度在各时间点明显减轻；而肾组织的ALR蛋白表达增加（P < 0.05）；肾小管上皮细胞增殖活跃；PCNA阳性细胞呈弥漫性分布，增殖指数（PI）明显升高（P < 0.05）。 结论 rrALR对急性损伤的肾小管上皮细胞具有减轻病变和促进再生修复的作用，可明显改善ARF大鼠的肾功能。     

阿魏酸钠对缺血性急性肾衰竭中SDF-1表达影响

目的：探讨阿魏酸钠对缺血性急性肾衰竭大鼠肾脏基质细胞衍生因子-1（SDF—1）表达的影响。方法：将雄性SD大鼠随机分为假手术组、缺血再灌注组、阿魏酸钠（SF）治疗组、SOD治疗对照组。检测肾功能;免疫组化、RT—PCR检测SDF-1的表达。结果：在假手术组,Scr（53．56±4．47）μmol／L,BUN（5．8±0．41）mmol／L;缺血再灌注导致大鼠肾脏损伤明显,Scr（105．10±6．31）pmol／L,BUN（19．60±0．56）retool／L;SF治疗后,血清Scr、BUN水平较IR组下降明显。在SF20mg治疗组,Scr（80．92±5．02）μmol／L,BUN（13．64±0．53）mmol／L;在SF40rng治疗组,Scr（66．88±4．86）μmol／L,BUN（10．46±0．79）mmol／L;在SOD治疗对照组,Scr（57．04±2．1）μmol／L,BUN（7．98±0．48）mmol／L。在假手术组SDF-1有微量表达;大鼠肾脏缺血45min再灌注24h,肾组织SDF-1蛋白、mRNA的表达上调。阿魏酸钠上调SDF-1蛋白、mRNA的表达更加明显。SOD亦能上调SDF-1蛋白、mRNA的表达。结论：在缺血性急性肾衰竭中,阿魏酸钠可促进肾组织表达SDF-1,可能是促进造血干细胞（HSC）向肾脏归巢、加速损伤肾脏修复的机制之一。     

骨碎补总黄酮对急性肾衰竭大鼠ICAM-1基因表达的影响

目的：研究骨碎补总黄酮（AFFDR）对大肠杆菌脂多糖（LPS）诱导的急性肾衰竭大鼠肾组织细胞间黏附因子-1（ICAM-1）mRNA表达的影响。方法：用LPS（30mg/kg）腹腔注射建立急性肾衰竭大鼠模型,分模型组（LPS组）、骨碎补总黄酮治疗组（LPS＋AFFDR组）、正常对照组（Control组）和骨碎补对照组（AFFDR组）。实验第7天测定各组大鼠血清肌酐（Scr）的含量,观察肾脏的超微结构和ED-1阳性巨噬细胞的浸润,并用半定量RT-PCR方法检测AFFDR对肾组织ICAM-1 mRNA表达的影响。结果：LPS引起大鼠Scr明显升高,肾脏近曲小管出现明显病理改变。AFFDR有效降低LPS攻击大鼠Scr的含量,明显减轻近曲小管的损伤。LPS组肾组织ED-1阳性巨噬细胞浸润和ICAM-1 mRNA的表达明显高于对照组,而LPS＋AFFDR组肾组织ED-1阳性巨噬细胞的浸润和ICAM-1 mRNA的表达明显低于LPS组。结论：AFFDR防治内毒性急性肾衰竭的作用机制可能与其抑制肾组织ED-1阳性巨噬细胞浸润和ICAM-1的表达有关。     

红细胞生成素对慢性肾衰竭大鼠残肾组织归巢因子表达的影响

目的 观察红细胞生成素(EPO)对慢性肾衰竭(CRF)大鼠肾组织归巢因子表达的影响.方法 采用分阶段5/6肾切除制备大鼠CRF模型.实验动物随机分为3组:假手术组、CRF模型组和EPO治疗组.从第3周开始,治疗组大鼠每次皮下注射重组人EPO 50 IU/kg,每周3次,共6周.8周后检测各组大鼠血肌酐(Scr)、血尿素氮(BUN)、尿蛋白、血红蛋白(Hb)；采用实时荧光定量PCR、Western印迹和免疫组化方法检测残肾组织EPO及其受体(EPOR)、归巢因子及其受体(SDF-1、CXCR4、Ang-1、Tie2、SCF、c-Kit)的表达.结果 与模型组比较,EPO治疗可上调残肾组织归巢因子及其受体(SDF-1、CXCR4、Ang-1、Tie2、SCF、c-Kit)mRNA和蛋白的表达(均P＜0.05)；同时,EPO治疗还可上调残肾组织EPO及EPOR的mRNA和蛋白的表达(均P＜ 0.05).此外,EPO治疗还能下调大鼠Scr、BUN和尿蛋白水平(均P＜0.05),上调Hb水平(P＜0.05).结论 EPO能改善慢性肾衰竭大鼠的肾功能,这种作用可能与其激活残肾组织归巢因子而参与损伤肾脏的修复有关.     

缬沙坦对糖尿病肾病大鼠肾间质纤维化的作用

目的 探讨缬沙坦在防治糖尿病肾病(DN)大鼠肾间质纤维化( RIF)中的作用及其机制.方法 54只大鼠随机被分为对照组(C组)、DN模型组(D组)和缬沙坦治疗组(T组).D组和T组大鼠分别给予链脲菌素( STZ)一次性腹腔注射建立糖尿病大鼠模型.造模后T组给予缬沙坦混悬液40 mg· kg-1·d-1,分别于实验第4周、第8周和第12周末测血糖、血浆白蛋白、Scr、尿蛋白.Masson染色观察RIF面积.免疫组化法检查肾组织缺氧诱导因子1α( HIF-1α)、金属蛋白酶1组织抑制剂(TIMP-1)、基质金属蛋白酶9(MMP-9)的表达.实时荧光定量PCR测定其mRNA表达.结果 与C组比较,D组及T组大鼠24 h尿蛋白量、Scr均显著升高,肾组织RIF面积、HIF-1α、TIMP-1蛋白及mRNA表达均显著增加,血清白蛋白及肾组织中MMP-9蛋白及其mRNA表达均明显减少,差异均有统计学意义(均P＜0.05).与同时间点D组比较,T组在实验第8周末、第12周末24h尿蛋白、Scr均显著降低,肾组织中RIF面积、HIF-1α、TIMP-1蛋白及其mRNA表达均显著减少,血清白蛋白及肾组织中MMP-9及其mRNA表达均显著增多,差异均有统计学意义(均P＜0.05).结论 缬沙坦可能通过下调HIF-1α、TIMP-1表达,上调MMP-9表达,延缓肾间质纤维化.     

HIF-VEGF-Notch信号通路相关因子在阿霉素肾病大鼠肾小球硬化过程中的表达研究

目的:探讨HIF-VEGF-Notch信号通路相关因子在阿霉素肾病大鼠肾小球硬化过程中的表达。方法:SD大鼠随机分为对照组和模型组(实验组),建立阿霉素肾病大鼠模型,第4、8、12、16周检测大鼠24 h尿蛋白、血清白蛋白(Alb)、尿素氮(BUN)、肌酐(Scr),光镜下观察肾组织病理改变,采用RT-PCR检测肾组织HIF-1 mRNA、VEGF mRNA、Notch1 mRNA表达水平,并采用Western blot法检测肾组织缺氧诱导因子-1α(HIF-1α)、血管内皮生长因子(VEGF)、Notch1蛋白表达水平。结果:实验组大鼠肾脏呈典型的肾小球硬化改变。与对照组相比,第4、8、12、16周实验组大鼠尿蛋白明显升高(P 0. 01); Alb均明显下降(P 0. 01); BUN、Scr持续升高,有显著性差异;实验组大鼠肾组织第4、8、12、16周HIF-1 mRNA、VEGF mRNA、Notch1 mRNA均表达升高(P 0. 01);肾组织HIF-1α、VEGF、Notch1蛋白水平也明显升高(P 0. 01)。结论:HIF-VEGF-Notch信号通路相关因子的高表达可能与阿霉素肾病肾小球硬化进展有关。     

厄贝沙坦对糖尿病大鼠肾组织MCP-1表达的影响

目的：观察厄贝沙坦对糖尿病大鼠肾组织中单核细胞趋化蛋白-1（MCP-1）表达的影响,并探讨其对肾组织的保护作用。方法：高糖高脂饮食联合小剂量腹腔注射链脲佐菌素（streptozotocin STZ,30mg/kg）建立2型糖尿病大鼠模型。Wistar大鼠30只,随机分为正常对照组（A组）、糖尿病组（B组）与厄贝沙坦治疗组（C组）。于实验第12周和16周末检测大鼠血糖（BG）、胆固醇（TC）、三酰甘油（TG）、血尿素氮（BUN）、血肌酐（Scr）、24h蛋白定量（24U-pro）。第16周处死各组大鼠,测肾重指数（肾重KW/体重BW）。光镜观察肾组织的形态结构,实时荧光定量PCR和免疫组化法检测肾组织中MCP-1mRNA及蛋白的表达。结果：（1）糖尿病组大鼠的BG、TC、TG、BUN、Scr、24U-pro、KW/BW均明显高于正常对照组（P〈0.01）;肾组织MCP-1mRNA及蛋白的表达明显高于正常对照组（P〈0.01）。（2）与糖尿病组相比,厄贝沙坦治疗组大鼠的BG、TC、TG、BUN、Scr、24U-pro、KW/BW在第16周均被显著抑制（P〈0.05,P〈0.01）,肾组织MCP-1mRNA及蛋白的表达明显低于糖尿病组（P〈0.01）。结论：厄贝沙坦可以通过抑制肾脏MCP-1的表达来延缓糖尿病肾脏疾病的进展。     

β_1-整合素在急性肾小管损伤大鼠中表达变化的实验研究

目的 :通过观察 β1-整合素在大鼠急性肾小管损伤中表达的变化 ,探讨β1-整合素在急性肾小管损伤中的作用。方法 :用庆大霉素建立大鼠急性肾小管损伤模型。将大鼠随机分为庆大组、庆大 +整合素抗体组及对照组 ,测定各组血肌酐 (Scr)、血尿素氮 (BUN)的变化 ,并用反转录 -多聚酶链式反应 (RT -PCR)方法测定肾组织 β1-整合素mRNA表达的变化。结果 :庆大组在各个时间点的血肌酐、血尿素氮值分别显著高于庆大 +整合素抗体组及对照组 ;β1-整合素mRNA的表达变化在各组也有相同的结果。结论 :β1-整合素在肾小管损伤中起着十分重要的作用 ,整合素抗体可改善肾小管损伤引起的肾功能异常     

红细胞生成素对慢性肾衰竭大鼠肾小球内皮细胞功能的影响

目的 探讨红细胞生成素（EPO）对慢性肾衰竭（CRF）大鼠肾小球内皮细胞功能的影响。 方法 采用分阶段5/6肾切除术制备大鼠慢性肾衰竭动物模型。实验动物按数字随机法分为4组：假手术组（对照组）、慢性肾衰竭组（模型组）及EPO干预的两个剂量组（小剂量组EPO用量30 U/kg,大剂量组EPO用量50 U/kg）。慢性肾衰竭大鼠皮下注射EPO 6周后处死。检测各组大鼠血肌酐（Scr）、血尿素氮（BUN）、尿蛋白、血红蛋白（Hb）和血压的变化,并观察肾组织病理改变。免疫组化法检测肾小球CD34、CD31表达;RT-PCR检测肾组织内皮素1（ET-1）、内皮细胞一氧化氮合酶（eNOS）和血管内皮细胞生长因子（VEGF） mRNA的表达。 结果 与模型组比较,EPO治疗能显著增加大鼠肾小球CD34、CD31的表达（均P < 0.05）;下调肾组织ET-1 mRNA的表达（P < 0.05）;上调肾组织eNOS和 VEGF mRNA的表达（均P < 0.05）。此外,EPO治疗还能使大鼠Scr、BUN、尿蛋白和血压水平显著降低（均P < 0.05）,Hb水平显著增高（P < 0.05）,肾组织病理损害明显减轻。 结论 EPO能减轻慢性肾衰竭大鼠肾脏的病理损害,改善肾功能。这种作用可能与其促进肾小球内皮细胞的修复和改善内皮功能有关。     

益肾胶囊对糖尿病肾病大鼠肾组织TGF-β1及Smad7表达的影响

目的：探讨益肾胶囊对糖尿病肾病大鼠肾组织TGF-β1及Smad7表达的影响.方法：将32只雄性Wistar大鼠,随机分为对照组、糖尿病肾病模型组、氯沙坦治疗组、益肾胶囊治疗组,每组8只.治疗组给予氯沙坦钾（20 mg·kg-1·d-1）、益肾胶囊（625 mg· kg-1·d-1）灌胃8周.测定血糖、24 h尿蛋白定量、血肌酐（Scr）和尿素氮（BUN）,计算内生肌酐清除率（Ccr）;观察肾脏病理变化及肾组织中TGF-β1和Smad7蛋白的表达.结果：与对照组相比,糖尿病肾病模型组大鼠血糖、24h尿蛋白定量、Scr和BUN明显升高,Ccr显著降低;肾组织出现较明显的病理损伤;且肾组织TGF-β1表达显著上调,Smad7蛋白表达量明显减少.益肾胶囊治疗后,与糖尿病肾病模型组相比,24 h尿蛋白定量、Scr和BUN明显下降,Ccr显著上升;肾组织病理损伤程度减轻;此外,肾组织TGF-β1表达显著下调,Smad7蛋白表达量明显增加.结论：益肾胶囊可能通过调节TGF-β1/Smad的表达,从而对糖尿病肾病发挥肾脏保护作用.     

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.     

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.     

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.