骨髓间充质干细胞介导大鼠肺内基因转移的可行性

目的评价骨髓间充质干细胞(MSCs)介导大鼠β-半乳糖苷酶(Lac-Z)基因肺内转移的可行性。方法对原代培养的Lewis大鼠MSCs进行Lac-Z表达载体(pSV-β-Gal)转染和DAPI荧光染色标记,再将MSCs(5×105细胞/每只大鼠)经颈静脉输入同基因背景受体Lewis鼠体内(n=10),48 h 和8周后处死大鼠(每时点5只大鼠),制作肺、脾、肝、肾、骨骼肌标本,荧光显微镜观察荧光标记的移植细胞,将肺组织与X-gal色素原一起孵育检测Lae-Z基因表达产物。结果静脉输入细胞后48 h及 8周,脾、肝、肾组织仅见少量DAPI标记的阳性细胞,骨骼肌组织未见阳性细胞,但肺组织内可见较多 DAPI标记的阳性细胞,主要分布于肺间质和肺泡腔内。经颈静脉输入转染了pSV-β-Gal的MSCs后48 h及8周,肺组织标本与X-gal色素原溶液一起孵育后,显微镜下可见大鼠肺内散布着许多深蓝色标记的MSCs,而脾、肾中则仅见少量深蓝色标记的MSCs,肝、骨骼肌未见深蓝色标记的MSCs。结论颈外静脉注射基因修饰的MSCs具有较好的肺内靶向性,且在受体鼠肺可较长时间表达外源基因。     

骨髓间充质干细胞治疗慢性后肢缺血机理的初步研究

目的利用细胞示踪技术探讨骨髓间充质干细胞（MSCs）治疗慢性后肢缺血的相关机理。方法采用密度梯度离心法结合直接贴壁法分离和培养大鼠MSCs,并以5-溴脱氧尿嘧啶核苷（BrdU）标记。采用线栓法制备8只Lewis大鼠慢性后肢缺血模型,将其随机均分为MSCs移植组和对照组,分别于患侧后肢肌肉注射MSCs和生理盐水。分别于移植术后第7天和第14天,对其进行临床观察、后肢血流量测定及后肢血管造影,再于相应时间点处死大鼠,取患侧后肢股四头肌和腓肠肌,行HE染色及BrdU免疫组化染色。结果移植术后14 d,8只大鼠全部成活,移植部位均无坏死和肿瘤形成;MSCs移植组大鼠患侧/健侧后肢的血流灌注比值明显增高（1.773比1.279）,而血管造影结果提示2组大鼠的侧支血管数量比值未见显著增加（0.908比0.835）。HE染色结果示2组大鼠的股四头肌及腓肠肌并未发生特殊的病理学变化。BrdU免疫组化结果显示,阳性颗粒定位为股四头肌及腓肠肌的间质细胞和血管内皮细胞;且MSCs的分布存在差异,移植术后7 d腓肠肌内阳性细胞所占比例明显高于股四头肌,而14 d时则相反。结论 MSCs移植在术后早期可以提高血流灌注量,但这并非为增加了侧支血管数量使然,MSCs移植后所引起的旁分泌效应可能在术后早期起着重要的作用。     

骨髓间充质干细胞对缺血再灌注损伤肾小管上皮细胞增殖和凋亡的影响

目的：探讨外源性骨髓间充质干细胞（MSCs）移植对缺血再灌注损伤（I/R）后肾小管上皮细胞增殖和凋亡的影响。方法：将雄性SD大鼠MSCs用DAPI标记后注入受体雌性SD大鼠体内。30只受体大鼠随机分为3组：假手术对照组（C组）、MSCs＋I/R组（M组）、DMEM-F12＋I/R组（D组）,每组10只。7d后观察肾功能,肾脏病理改变,采用原位末端标记法检测细胞凋亡指数,免疫组化法检测增殖细胞核抗原（PCNA）的表达,并观察DAPI标记的MSCs在受体大鼠肾脏的分布情况。结果：I/R后第7天,M组在肾功能、肾脏病理改变上,均明显好于D组;肾组织内PCNA＋细胞数和凋亡指数均低于D组。I/R后7d内未发现MSCs定位于肾组织中。结论：外源性MSCs可以促进I/R损伤后肾小管上皮细胞的增殖和减少细胞凋亡,从而有利于肾小管损伤的早期恢复。     

骨髓间充质干细胞分化为皮肤附属器细胞的初步实验研究

目的探讨骨髓间充质干细胞(marrowmesenchymalstemcells,MSCs)分化为创面皮肤附属器细胞的可能性,及其参与创面修复的可能机制。方法无菌条件下取Wistar大鼠股骨骨髓细胞,密度梯度离心分离、纯化MSCs,体外培养扩增后,用BrdU标记细胞。另于同种雄性Wistar大鼠背部正中,制备1cm×1cm全厚皮肤缺损创面模型,将BrdU标记的1×106/mlMSCs从阴茎静脉输注,术后第3天与第7天切取创面组织,行BrdU免疫组织化学单染色,以及BrdU和广谱角蛋白免疫组织化学双染色。结果BrdU阳性细胞出现在创面皮下组织、皮脂腺、毛囊和骨髓腔中。免疫组织化学双染色结果显示,皮脂腺和毛囊有BrdU阳性细胞,同时表达广谱角蛋白。结论创面愈合过程中,MSCs归巢并参与创面修复;在实验性全身皮肤缺损创面微环境下,MSCs可分化为皮肤附属器细胞。     

大鼠骨髓间充质干细胞移植治疗肾小管间质损伤的实验研究

目的:探讨骨髓间充质干细胞(MSCs)移植对大鼠单侧输尿管梗阻(UUO)后肾小管间质损伤的治疗效果。方法:密度梯度离心法和贴壁细胞培养法结合分离纯化MSCs。取成年雄性Wistar大鼠40只,随机分为移植组(组A,n=15)、对照组(组B,n=15)、假手术组(组C,n=10)。移植组和对照组分别结扎左侧输尿管,制作肾小管间质纤维化模型。移植组于结扎当日肾脏多点注射Brd U标记的含MSCs 1×10~6的DMEM培养基50μl,对照组注射等量DMEM培养基。假手术组开腹但不结扎输尿管。术后第14天处死各组大鼠,行HE染色,观察肾脏病理变化;免疫组化方法测定BrdU阳性细胞在肾脏的分布以及TGF-β_1,Ki-67的表达情况。结果:HE染色显示移植组与对照组肾脏间质损伤严重,两组相比无明显差异,假手术组正常。移植组肾实质内可见Brd U标记的MSCs,向周围组织分散,形态上与肾间质成纤维细胞类似,肾小管上皮细胞中未发现MSCs掺入。移植组较对照组TGF-β_1表达差异无统计学意义。移植组Ki-67表达较对照组有明显增强。结论:UUO大鼠骨髓间充质干细胞移植后,肾小管及间质细胞增生明显增高,提示骨髓间充质干细胞同种异体移植可能通过促进肾脏细胞的增生对肾间质损伤起到一定治疗作用。具体机制尚待进一步研究。     

转基因骨髓间充质干细胞移植对大鼠缺血脑组织转换生长因子-β1表达的影响

目的探讨碱性成纤维细胞生长因子(bFGF)转染间充质干细胞(MSC)对大鼠缺血皮层脑组织转换生长因子-β1(TGF-β1)mRNA表达的影响。方法电穿孔法将bFGF基因转染MSCs,免疫组织化学及双标记法鉴定bFGF表达;逆转录-聚合酶链反应(RT-PCR)检测缺血脑组织TGF-β1mRNA的表达。结果移植7、14d发现转基因MSCs缺血脑组织表达bFGF。MSCs移植组和转基因MSCs移植组比较,移植后7、14d的TGF-β1mRNA表达系数分别为(0.42±0.04、0.52±0.06)和(0.33±0.05、0.36±0.04),后者更显著的降低其表达,两组比较差异有统计学意义(P<0.01)。结论转染bFGF的MSCs移植后表达bFGF,并显著下调缺血脑组织TGF-β1mRNA的表达。     

补阳还五汤对骨髓间质干细胞移植治疗大鼠脊髓损伤的影响

目的:观察补阳还五汤联合骨髓间质干细胞(MSCs)移植对大鼠脊髓损伤后神经功能恢复以及移植的MSCs迁移情况的影响,并探讨其作用机制。方法:SD大鼠80只,其中70只用改良Allen法制备大鼠T10脊髓损伤模型,并随机分为中药+MSCs组20只、MSCs组20只、假手术组(无脊髓损伤)10只、中药组20只、空白对照组(无治疗)10只。中药+MSCs组、MSCs组、假手术组行大鼠尾静脉移植带Brdu标记的MSCs。各组大鼠于术后1、3、5周观察神经功能恢复、免疫组化检测带标记的MSCs迁移情况。结果:与空白对照组相比,治疗组神经功能测定在术后1、3、5周时均明显高于对照组(P<0·01)。术后1周移植组的脊髓组织内即可见Brdu标记阳性细胞(假手术组除外),术后5周中药+MSCs组Brdu阳性细胞计数较MSCs组有显著性差异(P<1.05)。结论:静脉注射移植的MSCs能够迁移到脊髓损伤组织,并促进神经功能的恢复。补阳还五汤能促进移植的MSCs迁移,同时有利于脊髓功能的恢复。     

自体原位移植肾缺血再灌注损伤模型的建立与环孢素A对移植肾的保护作用

目的建立一种新的移植肾缺血再灌注损伤(IRI)动物实验模型并寻找一种新的移植肾保护方法。方法40只兔随机分为A组(生理盐水对照组)、B组(单纯灌注液组)、C组[环孢素A(CsA)+灌注液组,CsA浓度为0.01‰,W/V]、D组(CsA+灌注液组,CsA浓度为0.03‰,W/V)。用套管针穿刺左肾动、静脉,灌注肾脏。原位低温保存2h后,切除右肾并开放左肾血流使左肾复灌。于术后6、24h分别取血标本,24h后取左肾标本,测定血尿素氮(BUN)、血肌酐(Cr),TUNEL法检测分析左肾小管上皮细胞凋亡率,免疫组织化学法测定左肾组织HSP70的表达。结果D组6、24hBUN为(8.60±0.25)mmol/L、(7.99±0.14)mmol/L;Cr为(79.90±1.37)μmol/L、(78.98±1.66)μmol/L,细胞凋亡指数为0.075±0.035,明显低于其他各组;HSP70表达为(0.211±0.025)μm2,明显高于其他各组。结论本模型能客观反映移植肾缺血再灌注损伤状态,0.03‰CsA复合肾灌注液能明显降低移植肾缺血再灌注损伤。     

缺血后处理对大鼠缺血再灌注肾损伤后尿NGAL蛋白表达的影响

目的:评估缺血后处理(ischemic postconditioning,IPO)对大鼠缺血再灌注肾损伤(ischemia/reperfusion injury,IRI)的保护作用,及其对尿中性粒细胞明胶酶脂质相关运载蛋白(neutrophil gelatinase-associated lipocalin,NGAL)表达的影响。方法:雄性SD大鼠144只,体重180~200 g,随机分为3组(n=48):缺血再灌注组(IRI组):夹闭双侧肾蒂45 min后恢复灌注;缺血后处理组(IPO组):在IRI组基础上进行短暂反复6遍再灌注10 s/缺血损伤10 s处理后恢复灌注;假手术组(sham组):仅开腹,游离双侧肾脏,分离肾蒂不夹闭;每组于术前及术后2 h、6 h、12 h、24 h、48 h、72 h、96 h收集血、尿液及肾组织标本,苦味酸法检测大鼠血清肌酐(Scr),自动生化分析仪检测大鼠血尿素氮(BUN),ELISA法检测尿NGAL表达改变,显微镜下观察肾组织病理学改变。结果:肾组织病理检查结果示:12 h、24 h、48 h IPO组大鼠肾损伤程度较相应时间IRI组均明显减轻,与肾功能(Scr、BUN)结果一致(P0.05);与sham组相比:IPO及IRI组大鼠尿NGAL均在术后2 h开始升高,12 h到达峰值,除再灌注0 h、2 h外,IPO组各时间点尿NGAL表达均明显低于IRI组(P值均0.05)。结论:IPO对大鼠缺血再灌注肾损伤肾功能有保护作用,并可降低IRI所致的尿NGAL蛋白表达水平,NGAL可能成为肾IRI新的治疗靶点。     

红景天苷预处理对大鼠移植肾缺血再灌注损伤的保护

目的探讨红景天苷预处理对移植肾缺血再灌注损伤的保护机制。方法建立近交系雄性SD大鼠同基因肾移植模型。共设3个组,假手术组、红景天苷预处理组、移植缺血再灌注模型组,每组24只。观察红景天苷预处理对大鼠移植肾缺血再灌注过程中血清尿素氮(BUN)、肌酐(SCr)、过氧化物歧化酶(SOD)、脂质过氧化产物丙二醛(MDA)水平变化的影响;取移植肾组织HE染色后光镜观察肾组织病理学改变;荧光探针DCFH-DA检测活性氧(ROS)含量;采用免疫组织化学染色和放射免疫法分别检测肾组织中核转录因子κB(NF-κB)阳性细胞数目和肿瘤坏死因子-α(TNF-α)、白介素1(IL-1)、白介素-6(IL-6)的表达。结果红景天苷预处理组大鼠BUN、SCr、MDA在术后轻度升高,与假手术组比较无统计学差异(P0.05),与模型组比较有统计学差异(P0.01);SOD在术后24 h增加最明显,与假手术组比较有统计学差异(P0.05),与模型组比较有统计学差异(P0.05)。ROS含量在红景天苷预处理组术后上升,与假手术组比较有统计学差异(P0.05),但不如模型组升高明显,两组比较有统计学差异(P0.01)。红景天苷预处理组肾脏病理表现损伤较轻,与模型组比较有统计学差异(P0.05)。NF-κB阳性细胞数目在红景天苷预处理组术后表达略增加,在模型组表达明显增加,两组比较有统计学差异(P0.01)。肾组织匀浆中TNF-α、IL-1和IL-6含量在假手术组和红景天苷预处理组各时间段均未见明显变化,两组间比较无统计学差异(P0.05),而模型组含量明显增加,与其他两组比较差异有显著性(P0.01)。结论红景天苷预处理通过抑制氧化应激和减轻炎性因子对大鼠肾脏移植缺血再灌注后损伤具有一定的预防和保护作用。     

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.     

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.     

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.     

Dilemma of Membrane Biocompatibility and Reuse

Abstract: Numerous articles have been published on the multiple use of dialyzers and on the effect of different reprocessing chemicals and techniques on the dialyzer biocompatibility and performance. The results often appear contradictory, especially those comparing standard biocompatibility parameters. Despite this confusion, a discerning review of the published works allows certain limited conclusions to be drawn. Reprocessing of used hemodialyzers changes the biocompatibility profile of a dialyzer as defined by the parameters complement activation. leukopenia, and cytokine release. The effect of reprocessing depends on the chemicals and reprocessing technique applied and also on the type of membrane polymer being subjected to the reprocessing procedure. Reports of pyrogenic reactions indicate that the flux of the membrane also influences how suitable it is for safe reuse. An increased risk of allergic and pyrogenic reactions appears to be associated with dialyzer reuse. Furthermore, there has been a lack of investigations into the immunologic effect of the layer of adsorbed and chemically altered proteins that remains on the inner surface of reprocessed dialyzers. We conclude that the clinical benefit of dialyzer reuse cannot be generally accepted from a biocompatibility point of view.     

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.