异氟烷对发育期大鼠海马IL-1β mRNA、IL-6 mRNA和TNF-α mRNA表达的影响

目的 探讨异氟烷对发育期大鼠海马IL-1β mRNA、IL-6 mRNA和TNF-α mRNA表达的影响.方法 出生7 d的SD大鼠64只,随机分为2组(n=32):对照组(C组)和异氟烷麻醉组(I组).I组大鼠吸入1.5%异氟烷麻醉6 h,C组吸入空气.I组于麻醉前(T0,基础状态)、麻醉2 h(T1)、4 h(T2)、6 h(T3)、麻醉停止后4 h(L)、6 h(T5)、12 h(T6)、24 h(T7)时,C组在对应时点各取4只大鼠,测定海马IL-1β mRNA、IL-6 mRNA及TNF-α mRNA的表达水平.结果 C组各时点海马IL-1β mRNA、IL-6 mRNA和TNF-α mRNA比较差异无统计学意义(P＞0.05);与C组比较,I组海马T1～5 时IL-1βmRNA表达上调,T2,3 时IL-6 mRNA表达上调,T1～6时TNF-α mRNA表达上调(P＜ 0.05).结论 1.5%异氟烷麻醉可短暂上调发育期大鼠海马IL-1β mRNA、IL-6 mRNA和TNF-α mRNA的表达.     

手术创伤对不同月龄大鼠认知功能及海马小胶质细胞活化的影响

目的 评价手术创伤对不同月龄大鼠认知功能和海马小胶质细胞活化的影响.方法 健康雄性SD大鼠72只,3～4月龄,采用随机数字表法,将其分为2组:成年对照组(n=30)和成年手术组(n=42).健康雄性SD大鼠72只,18 ～ 20月龄,采用随机数字表法,将其分为2组:老年对照组(n=30)和老年手术组(n=42).手术组腹腔注射5%水合氯醛4～6 ml/kg麻醉下行剖腹探查术,对照组腹腔注射生理盐水1 ml/kg.于术后1～7d开始行水迷宫实验,术后1d采用条件恐怖适应实验检测大鼠术后空间和恐怖记忆能力,术后第1、3、7天时处死大鼠,取海马,采用免疫组化法检测小胶质细胞OX42表达.结果 与成年对照组比较,成年手术组大鼠僵直时间占总时间百分比降低,术后第1天海马小胶质细胞OX42表达上调(P＜0.05),逃避潜伏期及穿过原平台次数差异无统计学意义(P＞0.05);与老年对照组比较,老年手术组大鼠逃避潜伏期延长,穿过原平台次数减少,僵直时间占总时间百分比降低,术后第1和3天海马小胶质细胞OX42表达上调(P＜0.05).结论 手术创伤可降低成年大鼠恐怖记忆能力,但对空间记忆能力影响不明显;手术创伤可降低老年大鼠空间及恐怖记忆能力,与海马小胶质细胞活化有关.     

脾切除术对大鼠海马tau表达的影响

目的 评价脾切除术对大鼠海马tau表达的影响.方法 SD大鼠105只,随机分为3组,正常对照组(A组,n=15)不给予任何处理,麻醉组(B组,n=45)仅吸入1.5%异氟醚2 h,手术+麻醉组(C组,n=45)吸入1.5%异氟醚(吸入2 h)麻醉下实施脾切除术.B组和C组分别于麻醉后或术后1、3、7 d时处死15只大鼠,取海马组织,测定海马IL-1β mRNA、TNF-α mRNA、IL-1β、TNF-α、总tau、苏氨酸第205位点磷酸化tau(pT205 tau)、丝氨酸第396位点磷酸化tau(pS396 tau)、总糖原合成酶-3β(GSK-3β)和磷酸化GSK-3β(p-GSK-3β)的表达水平.结果 与A组比较,B组各时点IL-1β mRNA、TNF-α mRNA、IL-1β、TNF-α、总tau、pT205 tau、pS396 tau、GSK-3β和p-GSK-3β的表达水平差异无统计学意义(P＞0.05),C组术后IL-1βmRNA、TNF-α mRNA、IL-1β、pT205 tau和pS396 tau的表达上调,p-GSK-3β表达下调(P＜0.05或0.01).结论 手术创伤可导致大鼠海马tau磷酸化,其机制与手术创伤诱发炎性反应,从而激活GSK-3β有关.     

七氟烷对血管性认知功能损害大鼠炎性反应的影响

目的 探讨七氟烷对血管性认知功能损害大鼠炎性反应的影响.方法 成年雌性Wistar大鼠42只,体重200～250 g,随机分为3组:假手术组(S组,n=6)、血管性认知功能损害组(VCI组,n=18)和七氟烷组(Sev组,n=18).采用永久结扎大鼠双侧颈总动脉法建立血管性认知功能损害模型.Sev组于双侧颈总动脉结扎后,持续吸入七氟烷(呼气末浓度1.8%)和氧气0.5 L/min 12 h.S组于干预结束后2 d,VCI组和Sev组于干预结束后2、14、26 d时进行水迷宫实验和穿梭箱实验,记录学习、记忆潜伏期和被动、主动逃避次数.S组于干预结束后12 d,VCI组和Sev组于吸入七氟烷后12、24、36 d时各取6只大鼠,心脏取血后处死,取皮质和海马组织,采用酶联免疫吸附法测定血清和脑组织白细胞介素-1β(IL-1β)和肿瘤坏死因子-α(TNF-α)的水平,采用RT-PCR法测定脑组织IL-1β mRNA和TNF-α mRNA的表达.结果 与S组比较,VCI组和Sev组学习潜伏期延长,记忆潜伏期、被动和主动逃避次数降低,脑组织和血清IL-1β和TNF-α的水平升高,脑组织IL-1β mRNA和TNF-αmRNA的表达上调(P<0.01);与VCI组比较,Sev组学习潜伏期缩短,记忆潜伏期、被动和主动逃避次数增加,脑组织和血清IL-1β和TNF-α的水平降低,脑组织IL-1β mRNA和TNF-α mRNA的表达下调(P<0.01).结论 七氟烷可通过抑制炎性反应减轻大鼠血管性认知功能损害.     

七氟醚预处理对急性心肌缺血再灌注损伤大鼠认知功能的影响

目的 探讨七氟醚预处理对急性心肌缺血再灌注损伤大鼠认知功能的影响.方法 健康SD大鼠60只,雌雄各半,体重300～350 g,随机分为4组:正常对照组(C组,n=6),假手术组(S组,n=18)仅挂线不结扎左冠状动脉;急性心肌缺血再灌注组(IR组,n=18)结扎左冠状动脉30 min后恢复再灌注;七氟醚预处理组(SP组,n=18)吸入七氟醚1.0 MAC 60 min,停止吸入七氟醚后60 min结扎左冠状动脉,缺血30 min后恢复再灌注.分别于左冠状动脉结扎前(T1)、缺血30 min(T2)及再灌注120 min(T3)时抽取股动脉血1 ml,测定血浆丙二醛(MDA)浓度和超氧化物歧化酶(SOD)活性.C组随机取3只大鼠,其余各组于再灌注1、3、7 d各随机取3只大鼠测定海马长时程增强(LTP),C组取另外3只大鼠,其余各组于上述时点随机取3只大鼠,测定海马肿瘤坏死因子α(TNF-α)、TNF-α mRNA、白细胞介素1β(IL-1β)、IL-1β mRNA、血红素氧合酶(HO)-1的表达水平.结果 与C组和S组比较,IR组和SP组LTP降低;与IR组比较,SP组LTP升高(P＜0.05).与C组比较,IR组和SP组HO-1、IL-1β mRNA、IL-1β、TNF-α mRNA表达上调;与S组比较,IR组和SP组IL-1β mRNA及IL-1β表达上调;与IR组比较,SP组TNF-α mRNA、HO-1、IL-1β mRNA及IL-1β表达下调,血浆MDA浓度降低,SOD活性升高(P＜0.05).结论 七氟醚预处理可改善急性心肌缺血再灌注损伤大鼠认知功能,其机制可能与下调TNF-α、IL-1β表达有关.     

脾切除术对大鼠空间学习记忆能力的影响

目的 评价脾切除术大鼠术后空间学习记忆能力的变化。方法 SD大鼠98只，随机分为对照组（A组）、麻醉组（B组）和手术组（C组）。B组腹腔注射芬太尼0．2mg／kg、氟哌利多5mg／kg麻醉，不做手术。C组麻醉下行脾切除术。B、C组随机分为3个亚组（B1、B3、B7组和C1、C3、C7组，n=14），分别于麻醉或术后1、3、7d进行Y迷宫试验，测试大鼠的空间学习记忆能力，RT-PCR测定海马TNF-amRNA、IL-1βmRNA表达，Western-blot测定TNF-α、IL-1β蛋白的表达。结果 与A、B1组相比，C1组大鼠跑动所需的刺激电压增大，Y迷宫的学习次数增多；C3组Y迷宫的学习次数比A、B3组增多（P〈0．01）。C7组学习记忆成绩与A、B7组相似（P〉0．05）。与A、B1组相比，C1组海马TNF-α mRNA及IL-1β蛋白表达增多，C1、C3组海马IL-1βmRNA表达升高（P〈0．05）。结论大鼠脾切除术后发生短暂认知功能障碍，可能与海马TNF-α mRNA、IL-1β mRNA表达升高和IL-1β蛋白表达增多有关。     

氯化锂预先给药对老龄大鼠腹部手术后认知功能的影响

目的 探讨氯化锂预先给药对老龄大鼠腹部手术后认知功能的影响.方法 雄性SD大鼠48只,18月龄,体重550～700 g,随机分为3组(n=16):对照组(C组)、手术组(O组)和氯化锂预处理组(L组).L组腹腔注射氯化锂2 mmol/kg,1次/d,连续7 d,C组和O组给予等容量生理盐水.给药结束后O组和L组行腹部手术,术后24 h时测定海马IL-1β含量、总糖原合成酶激酶3β(GSK-3β)和磷酸化GSK-3β(p-GSK-3β)的表达水平,术后4～6 d行Morris水迷宫实验(记录逃逸潜伏期和游泳距离).结果 与C组比较,O组术后4～6 d逃逸潜伏期和游泳距离延长,海马IL-1β含量升高,p-GSK-3β表达下调,L组术后4 d游泳距离延长,海马IL-1β含量降低(P＜0.05),O组和L组总GSK-3β表达差异无统计学意义(P＞0.05);与O组比较,L组逃逸潜伏期和游泳距离缩短,海马IL-1β含量降低,p-GSK-3β表达上调(P＜0.05),总GSK-3β表达差异无统计学意义(P＞0.05).结论 氯化锂预先给药可改善老龄大鼠术后认知功能,其机制与抑制海马GSK-3β的活性,减轻海马炎性反应有关.     

大黄丹参对实验性重症急性胰腺炎大鼠肝胰组织TNF-a mRNA和IL-10 mRNA表达的影响

目的:观察中药大黄丹参治疗重症急性胰腺炎大鼠肝胰组织TNF-α mRNA和IL-10 mRNA表达的影响 .方法:SD大鼠30只,随机平均分成假手术组、重症急性胰腺炎对照组及大黄丹参治疗组.造模后6 h后用荧光PCR方法测定各组大鼠肝脏及胰腺组织TNF-α mRNA和IL-10 mRNA.结果:肝脏组织中,重症急性胰腺炎组大鼠TNF-α mRNA和IL-10 mRNA的表达均较假手术组有明显升高(P<0.05);中药治疗后TNF-α mRNA的表达下降(P<0.05),IL-10 mRNA的表达升高(P<0.05).胰腺组织中,重症急性胰腺炎组TNF-α mRNA和IL-10 mRNA表达同样升高(P<0.05),中药治疗后TNF-α mRNA的表达降低(P<0.05),但IL-10 mRNA表达与急性胰腺炎组比较无统计学差异.结论:SAP大鼠在肝脏和胰腺组织中,TNF-α mRNA和IL-10 mRNA均有明显升高,两者呈同一化的进程.大黄丹参治疗能够使肝胰组织的TNF-α mRNA表达下降,使肝IL-10 mRNA升高,显示了中药的调节作用.     

手术对异氟醚麻醉下老龄大鼠术后认知功能的影响

目的 探讨手术对老龄大鼠异氟醚麻醉下术后认知功能的影响.方法 健康雄性老龄SD大鼠72只,年龄20月,体重500～600 g,随机分为3组(n=24):对照组(C组)、异氟醚麻醉组(I组)和手术组(O组).C组吸入30%氧气2 h,I组吸入1.5%异氟醚和30%氧气的混合气体2 h,O组吸入1.5%异氟醚和30%氧气的混合气体2 h,并实施腹部手术.于麻醉结束后或术后24 h时随机取8只大鼠,取海马组织,采用免疫组织化学法和RT-PCR法分别测定神经元胆碱乙酰转移酶(ChAT)及ChAT mRNA的表达水平,其余大鼠进行Morris水迷宫实验,测定认知功能.结果 与C组比较,I组和O组逃避潜伏期延长,原平台象限停留时间缩短,穿越原平台次数减少,海马神经元ChAT mRNA及其蛋白表达水平降低(P<0.05);与I组比较,O组术后第4、5天逃避潜伏期延长,原平台象限停留时间缩短,海马神经元ChAT mRNA及其蛋白表达水平降低(P<0.05);与麻醉结束后或术后第3天比较,C组第4、5天逃避潜伏期差异无统计学意义(P>0.05),I组和O组逃避潜伏期延长(P<0.05);I组和O组麻醉结束后或术后第4、5天逃避潜伏期差异无统计学意义(P>0.05).结论 手术操作可加重异氟醚引起的老龄大鼠术后认知功能障碍,其机制可能与海马胆碱能神经元受损有关.     

手术创伤对老龄大鼠认知功能及海马铁调素和膜铁转运蛋白1表达的影响

目的 评价手术创伤对老龄大鼠认知功能及海马铁调素和膜铁转运蛋白1(FP1)表达的影响.方法 健康老龄雄性SD大鼠100只,18月龄,体重400～ 500 g,采用随机数字表法,将其分为2组(n=50):对照组(C组)腹腔注射水合氯醛麻醉,但不进行手术；手术创伤组(ST组)腹腔注射水合氯醛麻醉后行改良性剖腹探查术30 min.于术后24h时随机取10只大鼠,行水迷宫实验,测定认知功能,持续6d,分别于水迷宫实验第1、3、5、7天时随机取10只大鼠处死,取脑,分离海马,采用PCR和Western blot法检测海马铁调素和FP1的表达.结果 与C组比较,ST组水迷宫实验第3、4、5天时大鼠逃避潜伏期延长,原平台象限停留时间缩短,穿越原平台次数减少(P＜0.05),各时点海马铁调素表达上调,FP1表达下调(P＜0.05).结论 手术创伤可降低老龄大鼠认知功能,其机制可能与上调海马铁调素表达,下调FP1表达有关.     

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.