人脐血间充质干细胞的分离培养及其多向分化潜能的实验研究

目的 研究人脐血间充质干细胞(MSCs)分离培养的生物学特性及其向成骨、成脂诱导分化的能力.方法 从人脐血中分离扩增MSCs,显微镜下观察其形态及生长情况,绘制生长曲线,电镜下观察超微结构,流式细胞仪检测细胞表面标志物;成骨、成脂诱导后以碱性磷酸酶(ALP)染色、茜素红染色鉴定MSCs成骨分化潜能,油红O染色鉴定成脂分化潜能.结果 人脐血MSCs为成纤维细胞样,漩涡状贴壁生长排列,传至第110代细胞形态无明显变化;电镜下显示为低分化细胞;细胞表面不表达CD34和CD45,强表达CD29、CD44和CD90;成骨诱导后可检测到ALP表达及钙化结节形成;成脂诱导后可检测到脂滴形成.结论 人脐血中可分离出MSCs,与其他来源的MSCs具有类似的生物学特性及多向分化潜能,脐血有可能成为骨组织工程种子细胞的来源.     

诱导人孤雌胚胎干细胞向类间充质干细胞分化的实验研究

目的探索人孤雌胚胎干细胞在体外向类间充质干细胞诱导分化的方法 ,并鉴定所得细胞的生物学特性。方法人孤雌胚胎干细胞在无血清条件下悬浮培养,形成拟胚体,10d后在含血清条件下使拟胚体贴壁生长,7d后胰酶消化,所得细胞在含血清的培养液中传代、扩增。观察传代、扩增后细胞的形态学变化;用免疫荧光染色和流式细胞技术进行细胞表型分析;取第9代细胞进行成脂、成骨和成软骨诱导,9～28d后行特殊染色及RT-PCR分析。结果人孤雌胚胎干细胞在诱导分化后,形态与骨髓间充质干细胞相似,多次扩增传代后仍保持细胞形态和扩增能力。免疫荧光染色发现,细胞表达中胚层标志波形蛋白(Vimentin)。流式细胞分析显示,细胞表达CD29、CD105、CD166、CD44等间充质干细胞表面标志。特殊染色及RT-PCR分析显示:成骨诱导后,细胞碱性磷酸酶和茜素红染色阳性,碱性磷酸酶和Cbfa-1表达增加;成软骨诱导后,细胞Ⅱ型胶原染色阳性,Ⅱ型胶原和软骨寡聚基质蛋白(COMP)表达增强;成脂诱导后,细胞油红染色阴性,脂蛋白酶和Leptin无表达。结论人孤雌胚胎干细胞可以诱导、分化为间充质干细胞,并具有成骨、成软骨分化潜能。     

人瘢痕疙瘩成纤维细胞的干细胞特性研究

目的探讨人瘢痕疙瘩成纤维细胞是否具有间充质干细胞的生物学特性,从细胞分子学角度为进一步研究瘢痕疙瘩的发病机制提供基础研究资料。方法以人瘢痕疙瘩标本为研究对象,通过组织块贴壁法获得成纤维细胞,用流式细胞术检测细胞表面标志CD29、CD34、CD44及CD90的表达;采用免疫细胞化学法检测细胞波形蛋白、Oct4的表达;将体外诱导细胞向成骨细胞、成软骨细胞、成脂肪细胞方向分化。结果采用组织块贴壁法,从瘢痕疙瘩标本中获得成纤维细胞;经流式细胞术检测瘢痕疙瘩成纤维细胞呈高表达CD29、CD44、CD90等间充质干细胞表面标志;经免疫细胞化学法检测瘢痕疙瘩成纤维细胞的波形蛋白、Oct4呈阳性表达;体外诱导分化结果:瘢痕疙瘩成纤维细胞可向成骨细胞、成软骨细胞和成脂肪细胞分化,具有多向分化潜能。结论人瘢痕疙瘩成纤维细胞具有间充质干细胞的生物学特性,可能是瘢痕疙瘩发生、发展的重要因素。     

人骨髓间充质干细胞体外成骨分化过程中成骨相关基因的动态表达

目的：系统研究人骨髓间充质干细胞（hBMSCs）体外成骨诱导分化过程中成骨相关基因的表达变化。方法：应用密度梯度离心法分离hBMSCs,取第2代细胞通过流式检测及多向诱导分化方法进行干细胞鉴定;应用RT-PCR法对hBMSCs在体外成骨诱导不同时间点的成骨相关基因表达进行检测。结果：第2代hBMSCs表达间充质干细胞表面标志CD44、CD90,具有成脂和成骨分化潜能。成骨相关基因在诱导早期部分表达,中期均有表达,基因表达大部分在14天达高峰,与矿化相关的基因表达在21天达高峰。结论：hBMSCs体外成骨诱导过程中成骨相关基因呈动态表达,其表达时序与成骨细胞生理发育基本相似。     

脐血间充质干细胞的分离培养鉴定及诱导分化研究

目的：分离培养人脐血间充质干细胞（human umbilical cord blood-derived mesenchymal stem cells,hUCB-MSC）,体外观察其生长特性,并在特定条件下诱导分化,探讨其成脂成骨分化能力.方法：采用沉降法和密度梯度离心结合贴壁培养法自脐血中分离间充质干细胞,倒置显微镜下观察其形态及生长情况;流式细胞仪分析细胞周期并检测细胞表面标志物;用茜素红染色和油红0染色分别鉴定其成骨成脂分化能力.结果：纯化的hUCB-MSC贴壁生长,呈均一梭形,具有较强的增值能力,流式细胞仪分析P3代hUCB-MSC稳定表达间充质干细胞表面抗原标志CD73,CD105和CD90等,不表达造血标志CD34和CD45;成骨诱导后3周后细胞茜素红染色阳性;成脂诱导3周后细胞油红0染色阳性.结论：本实验分离的hUCB-MSC具有较强的增殖能力,表达间充质干细胞的表面标记,具有成骨成脂分化潜能.     

人脂肪组织来源干细胞体外增殖分化中端粒酶的表达

目的 探讨体外培养条件下人脂肪干细胞增殖和分化过程中端粒酶的表达水平,为其作为种子细胞的应用研究提供理论基础.方法 体外分离、培养人脂肪干细胞并传代,行流式细胞表面抗原分析,并用油红O染色及茜素红染色行成骨和成脂诱导分化的鉴定;采用TRAP法分别检测新鲜的不同时间培养的人脂肪干细胞和诱导分化为脂肪细胞的人脂肪干细胞的端粒酶活性.结果 脂肪干细胞具有向脂肪细胞、成骨细胞多向分化的能力,且表达干细胞相关表面标志物.新鲜分离和传代的脂肪干细胞,在体外培养12代内端粒酶活性呈阴性或低水平表达;一旦经过成脂诱导分化,细胞端粒酶活性表达上调,培养3～6 d后端粒酶活性开始出现逐渐降低.结论 用胶原酶消化法从脂肪抽吸术中得到的细胞主要是人脂肪干细胞;在体外培养增殖的过程中,人脂肪干细胞的端粒酶活性未见异常表达;成脂诱导分化早期人脂肪干细胞端粒酶活性增高,其后开始出现下降趋势.     

阿司匹林对Ⅰ型成骨不全小鼠脂肪来源间充质干细胞增殖和成骨分化的影响

目的探讨阿司匹林对Ⅰ型成骨不全小鼠脂肪来源间充质干细胞增殖和成骨分化能力的影响。方法从Ⅰ型成骨不全小鼠的脂肪组织中分离培养的脂肪间充质干细胞(ADSCs~(col1a1+/-)),经流式细胞仪检测其表面间充质干细胞相关Marker CD 29、CD 45等的表达情况,并在成骨诱导7 d后进行ALP染色、成脂诱导14 d后进行油红O染色,验证ADSCs~(col1a1+/-)的成骨和成脂分化潜能;分别配制含0、0.5、1、1.5、2、5、10 mmol/L阿司匹林的培养基,MTS检测不同浓度阿司匹林对ADSCs~(col1a1+/-)增殖的影响;将ADSCs~(col1a1+/-)分为对照组、单纯成骨诱导组和加入1.5 mmol/L阿司匹林的成骨诱导+阿司匹林组进行成骨诱导,比较ALP染色结果及ALP活性,qPCR检测成骨相关基因及相关信号通路因子转录水平的变化。结果分离培养的ADSCs~(col1a1+/-)高表达间充质干细胞相关Marker CD 29及CD 45,低表达CD 44,并具有成骨、成脂分化潜能;低、中浓度(0～2 mmol/L)的阿司匹林可促进ADSCs~(col1a1+/-)增殖,高浓度(5～10 mmol/L)时则抑制,浓度为1.5 mmol/L时促增殖效果最明显;与对照组和单纯成骨诱导组相比,成骨诱导+阿司匹林组的ALP表达明显增强,成骨相关基因col1a1、bglap、runx2、osterix和Wnt信号通路中β-catenin以及TGF-β通路中bmp2的转录水平有显著上调。结论阿司匹林能够促进ADSCs~(col1a1+/-)的增殖和成骨分化,可能是通过Wnt及TGF-β信号通路来促进成骨分化的。     

人增生性瘢痕成纤维细胞的间充质干细胞表型及多向分化潜能

目的 探讨人增生性瘢痕来源的成纤维细胞的细胞表型及分化潜能,以进一步研究其在增生性瘢痕形成中的作用.方法 从手术切除的增生性瘢痕中提取并分离培养成纤维细胞,以倒置显微镜观察其细胞形态及生长特点.待细胞培养传代至第3代,采用Vi-CELL细胞计数仪检测细胞生长情况,流式细胞仪检测成纤维细胞间充质干细胞表型标志CD73、CD44、CD105、CD90、CD34、CD45、CD14的表达情况;通过免疫细胞化学检测该细胞CK19、Oct 4、Vementin的表达情况及免疫荧光检测α-平滑肌肌动蛋白;诱导分化检测细胞向成骨、成软骨和成脂细胞方向分化能力.结果 细胞原代培养初期贴壁散在分布,生长曲线显示细胞1 ～2d生长较慢,从3～5d左右细胞生长较快,6～7d细胞进入平台期;第2代第5天细胞多为长梭形,呈放射状、漩涡状排列.细胞流式结果显示细胞表型CD90、CD44、CD105、CD73呈高表达,CD45、CD34、CD14不表达;免疫细胞化学检测间充质细胞标记物Vementin、多能干细胞标志物Oct 4均呈阳性表达,免疫荧光检测α-平滑肌肌动蛋白呈阳性表达,上皮细胞标志物CK19呈阴性表达,多向诱导分化实验该细胞可向成骨、成软骨和成脂细胞分化,具有多向分化潜能.结论 人增生性瘢痕来源成纤细胞具有间充质干细胞样生物学特性,该生物学特性可能在增生性瘢痕的形成以及创面修复中发挥至关重要的作用.     

骨折后外周血间充质干细胞浓度变化的实验研究

[目的]观察骨折后不同时间点外周血间充质干细胞(MSCs)浓度变化,并比较其与骨髓间充质干细胞生物学特性的异同.[方法]根据不同处理条件将SD大鼠分为:对照组和骨折组(骨折后1、3、7d共3组),每组20只.分别于骨折后1、3、7d抽取外周血,密度梯度离心法分离培养外周血MSCs,计数成纤维细胞集落形成单位(CFU-Fs)数.流式细胞仪检测细胞表面标记(CD44、CD90、CD34、CD45).成骨、成脂诱导,碱性磷酸酶、茜素红和油红染色检测其分化特性.[结果]原代外周血MSCs呈集落生长,骨折组集落数明显多于对照组,其中以骨折后3d组形成的集落数最多,具有显著差异(27.25±11.52 CFU-Fs/cuhure vs 2.80±3.96 CFU-Fs/culture,P＜0.01).外周血MSCs高表达CD44、CD90,低表达CD34、CD45,不同的是CD34小部分呈阳性(＜20％).与对照组骨髓MSCs的诱导结果相同,外周血MSCs成骨诱导后28 d出现钙结节,茜素红染色阳性;成脂诱导后21 d有大量脂滴出现,油红染色阳性.[结论]外周血体外密度梯度离心法分离培养的细胞具有多潜能分化的MSCs表面标记且可以向成骨、成脂分化.骨折后外周循环中MSCs数量明显增多,呈一定的时序性变化,可能参与骨折修复.     

人脂肪干细胞的体外培养鉴定及分化特性

目的：在体外从脂肪块中分离出脂肪干细胞（adipose derived stem/stromal cells,ASCs）,对其进行形态观察、干细胞鉴定、增殖和分化能力检测。方法：将腹部取皮术的皮下脂肪利用胶原酶消化法,进行体外分离培养,取第3代的细胞进行细胞爬片HE染色、流式鉴定、MTT、细胞周期检测等,利用成脂和成骨培养液诱导,油红O和茜素红染色鉴定诱导结果。结果：原代培养第1次换液时细胞多呈多角形和短梭形,第3代ASCs细胞爬片HE染色显示形态多为长梭形,呈漩涡状生长;流式鉴定显示：CD29＋,CD31-,CD34-,CD44＋,CD45-,CD49＋,CD106-,CD133-;MTT显示ASCs生长增殖活性强;细胞周期检测结果显示：G1=86.8%,G2=8.77%;成脂诱导后油红O染色阳性,对照组为阴性;成骨诱导后茜素红染色阳性,对照组为阴性。结论：人ASCs具有贴壁生长、多向分化以及干细胞表型等特征,且生长增殖活性强,是一种很有应用前景的间充质干细胞。     

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.