静脉输注高氧液对家兔小肠缺血再灌注损伤的影响

目的 评价静脉输注高氧液对家兔小肠缺血再灌注损伤的影响.方法 健康成年家兔24只,雌雄不拘,体重2.5 ～ 3.2 kg,采用随机数字表法,将家兔随机分为3组(n=8):假手术组(S组)、小肠缺血再灌注组(I/R组)和静脉输注高氧液组(HOS组).S组仅开腹游离但不夹闭肠系膜上动脉,I/R组和HOS组采用夹闭肠系膜上动脉1h恢复灌注2h的方法制备家兔小肠缺血再灌注模型,于夹闭肠系膜上动脉即刻HOS组耳缘静脉输注高氧液20 ml·kg-1 ·h-1,I/R组静脉输注等容量生理盐水.于再灌注2h时采集下腔静脉血样,检测血清乳酸浓度,处死家兔取小肠组织,测定丙二醛(MDA)含量、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、谷胱甘肽过氧物酶(GSH-Px)的活性,光镜及电镜下观察肠上皮组织病理学结果,行肠黏膜损伤评分.取内脏组织,观察细菌移位情况.结果 与S组相比,I/R组和HOS组肠组织MDA含量、血清乳酸浓度和细菌移位率升高,SOD、CAT和GSH-Px活性降低(P＜0.05);与I/R组相比,HOS组肠组织MDA含量、血清乳酸浓度和细菌移位率降低,SOD、CAT和GSH-Px活性降低(P＜0.05).结论 静脉输注高氧液可减轻家兔小肠缺血再灌注损伤.     

肠系膜上动脉灌注高氧液对家兔肠缺血-再灌注损伤的保护作用

目的探讨术中肠系膜上动脉(SMA)灌注高氧液对家兔肠缺血再灌注损伤的保护作用及机制。方法健康家兔32只,随机均分为假手术组(S组)、缺血再灌注组(I组)、高氧液灌注组(H组)和灌注对照组(C组)。开腹夹闭SMA1h造成缺血,松夹再灌注2h制作肠缺血再灌注模型。H组在缺血期经SMA以20ml·kg-1·h-1恒速灌注高氧液1h,C组则采用同样方法输入等容量的5%葡萄糖液。再灌注2h后分别测定各组肠组织丙二醛(MDA)含量及超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和谷胱甘肽过氧化物酶(GPX)活性;观察光镜下各组肠粘膜组织形态学改变;测定肠粘膜组织ATP含量,并测定肠道的氧摄取率。结果小肠缺血再灌注后,肠组织MDA含量明显升高,SOD、CAT和GPX活性明显下降,光镜下肠粘膜损伤严重,肠粘膜组织ATP含量及肠道的氧摄取率均明显下降。I组与C组各参数差异无显著意义。与I组和C组相比,H组肠组织MDA含量明显降低(P<0.01),SOD、CAT和GPX活性明显升高(P<0.05),光镜下肠粘膜损伤明显减轻,肠粘膜组织ATP含量及肠道的氧摄取率均明显增加(P<0.05,P<0.01)。结论术中经SMA灌注高氧液是一种安全有效的小肠保护方法,这与高氧液中的高氧分压有关,并通过增强抗氧化酶的活性减轻肠缺血再灌注损伤。     

肠道淤血再灌注在大鼠肝脏缺血再灌注损伤中的作用

目的:探讨肠道淤血再灌注在大鼠肝脏缺血再灌注损伤中的作用。方法:SD大鼠40只被分成4组:单纯肠道淤血再灌注肝脏组(E组)、无肠道淤血肝脏缺血再灌注组(I组)、肝脏缺血再灌注组(H组)、未处理组(S组),每组10只。测定血清谷丙转氨酶(ALT)、谷草转氨酶(AST)、肿瘤坏死因子-α(TNF-α)水平;测定肝组织丙二醛(MDA)含量和超氧化物歧化酶(SOD)活性;计算肝、肠系膜淋巴结肠道细菌移位率;镜下观察肝组织、肠黏膜形态变化;Western blot测定并计算肝组织NF-κb活化P65(P-P65)占P65的比例。结果:血清ALT、AST、TNF-α及肝组织MDA含量H组高于I组、E组高于S组(P0.05),肝组织SOD活性则相反。肝组织NF-κb、P-P65/P65值在E组、I组和H组较S组升高(P0.05),其中H组高于I组(P0.05)。结论:肠道淤血再灌注是加重肝脏缺血再灌注损伤的重要因素;肠道淤血再灌注能加重肝缺血再灌注损伤的发生机制可能与肠黏膜屏障受损致肠源性细菌移位,NF-κb被活化致炎症介质TNF-α等释放增加及肝脏抗氧化能力降低,氧化应激性损伤加重有关。     

依达拉奉对大鼠小肠缺血-再灌注所致肺损伤的保护作用

目的探讨依达拉奉对大鼠小肠缺血-再灌注所致肺损伤的保护作用。方法雄性SD大鼠18只,随机均分为假手术组(Sham组),缺血-再灌注组(IR组)和依达拉奉组(E组)。Sham组只分离肠系膜上动脉,不做其他处理;IR组分离肠系膜上动脉,从大鼠尾静脉注射与E组等量的生理盐水后,用无创动脉夹夹闭120min后移去动脉夹,再灌注120min;E组在缺血-再灌注前静脉注射依达拉奉6mg/kg。再灌注120min后采集标本。肺组织HE染色后病理学检测,采集腹主动脉血液检测大鼠血清中TNF-α和IL-6浓度,取肺组织检测髓过氧化物酶(MPO)活性和丙二醛(MDA)浓度。结果与Sham组比较,IR组肺泡上皮细胞广泛水肿、炎性细胞浸润、肺泡肺萎陷、肺毛细血管扩张出血;E组肺组织病理改变较IR组明显改善,肺泡炎性渗出减少;E组病理评分为(2.1±0.7)分,明显低于IR组的(5.7±1.1)分,IR组病理评分明显高于Sham组的(1.5±0.2)分(P0.01);血清中TNF-α和IL-6的浓度明显少于IR组,肺组织中MPO活性和MDA浓度明显低于IR组(P0.01)。结论依达拉奉能够明显改善小肠缺血-再灌注性肺损伤。     

肝缺血-再灌注损伤对大鼠肠黏膜屏障功能及肠道菌群易位的影响

目的观察大鼠肝缺血-再灌注后肠黏膜屏障功能的变化,并探讨其对肠源性细菌移位的影响。方法64只成年健康雄性SD大鼠,随机分为对照组和实验组,每组32只。实验组用无创微血管钳于肝门部夹闭肝动脉、门静脉和胆总管,45 min后去除血管钳,分别在全肝血流阻断45 min后再灌注即刻(0 h)、再灌注1 h、再灌注2.5 h、再灌注4 h共4个时间点采集标本,测定血浆肿瘤坏死因子α(TNF-α)、D-乳酸水平以及肠黏膜中丙二醛、特异性分泌型免疫球蛋白(sIgA)的含量;观察回肠壁组织病理学改变,取肠系膜淋巴结(MLN)、肝、脾、肺、肾及回肠组织匀浆进行细菌培养和鉴定。对照组仅分离门静脉、肝动脉及胆总管,不行血管阻断。结果实验组在再灌注即刻及再灌注后血浆TNF-α的水平不断升高,再灌注后的TNF-α的水平明显高于再灌注即刻(P<0.05);D-乳酸的水平也明显高于对照组,但组内不同时间点比较,差异无统计学意义;肠黏膜中丙二醛的含量明显高于对照组(P<0.05),再灌注后的含量明显高于再灌注即刻(P<0.05);而sIgA在再灌注即刻及再灌注后明显低于对照组(P<0.05)。随着肝缺血-再灌注时间的延长,实验组肠黏膜的病理改变逐渐加重。实验组在再灌注即刻在MLN、肝、脾、肺及肾组织中可培养出细菌,随着再灌注后时间的延长,实验组中MLN、肝、脾、肺及肾组织中检出细菌的动物数明显增多(P<0.05),培养出的细菌与回肠的优势菌分布一致。结论肝缺血-再灌注损伤导致肠屏障功能损害,且引起肠道菌群易位。     

色甘酸钠对大鼠肠缺血再灌注损伤的作用

目的 探讨肥大细胞膜稳定剂色甘酸钠对大鼠肠缺血再灌注损伤的作用。方法 32只SD大鼠随机分为4组（n=8）：假手术组（S组）、缺血再灌注组（I/R组）、缺血再灌注＋色甘酸钠25 mg/kg组（C1组）及缺血再灌注＋色甘酸钠50 mg/kg组（C2组）。采用肠缺血45 min再灌注1h制备肠缺血再灌注损伤模型,C1组、C2组再灌注前15min腹腔注射色甘酸钠。再灌注1h后,取小肠组织,光镜下观察小肠粘膜病理学改变,进行Chiu评分,电镜下观察小肠粘膜的超微结构,测定小肠肿瘤坏死因子-α（TNF-α）及组胺含量,进行肠粘膜肥大细胞（IMMC）计数,并测定类胰蛋白酶表达。结果 肠缺血再灌注导致小肠Chiu评分、TNF-α含量、IMMC计数及类胰蛋白酶表达增加,组胺含量降低,IMMC出现胞浆颗粒明显减少,颗粒包膜相互融合形成细胞内空泡等脱颗粒现象;色甘酸钠25、50mg/kg可减弱肠缺血再灌注导致的上述改变,且50mg/kg的作用更明显。Chiu评分与TNF-α、组胺、类胰蛋白酶水平有相关性,相关系数分别为0．532、-0．770（P＜0．05）。结论 色甘酸钠25、50mg/kg可抑制IMMC活性,减少TNF-α的释放,从而减轻了大鼠肠缺血再灌注损伤;色甘酸钠50mg/kg的效果较好。     

谷氨酰胺强化肠外营养对大鼠小肠黏膜缺血再灌注损伤的影响

目的：构建大鼠小肠缺血再灌注模型,观察谷氨酰胺强化肠外营养对小肠黏膜屏障作用的影响,并探讨其作用机制。方法：30只雌性Wistar大鼠,随机分为正常对照组（N组）、传统肠外营养组（TPN组）和谷氨酰胺强化肠外营养组（TPN＋Gln组）3组,每组10只。TPN组和TPN＋Gln组构建小肠缺血再灌注模型后予完全肠外营养5d。观察3组小肠黏膜形态、血浆D-乳酸、内毒素、TNF-α、IL-6水平及小肠黏膜HO-1 mRNA和蛋白的表达。结果：TPN＋Gln组与TPN组相比,小肠黏膜组织形态明显改善,血浆D-乳酸、内毒素、TNF-α和IL-6水平均显著性降低,HO-1 mRNA及蛋白表达水平明显增高。结论：谷氨酰胺强化肠外营养可以明显减轻大鼠缺血再灌注小肠黏膜屏障损伤及炎性反应,保护黏膜屏障完整性,并促进HO-1 mRNA表达及HO-1合成。HO-1及其代谢产物的抗氧化、抗凋亡及抗炎作用可能是谷氨酰胺保护缺血再灌注损伤小肠的作用机制。     

缺血预处理-后处理对大鼠肠缺血再灌注损伤的影响

目的 评价缺血预处理.后处理对大鼠肠缺血再灌注损伤的影响.方法 清洁级成年雄性SD大鼠40只.体重225～275 g,随机分为5组(n=8):假手术组(S组)仅分离肠系膜上动脉(SMA),不夹闭;肠缺血再灌注组(IIR组)采用夹闭SMA 60 min,再灌注60 min的方法制备肠缺血再灌注损伤模型;缺血预处理组(IPr组)夹闭SMA 10 min,再灌注10 min,余同IIR组;缺血后处理组(IPo 组)夹闭SMA 60 min后,再灌注30 s,缺血30 s,反复3次,再灌注60 min;缺血预处理.后处理组(IPr-IPo组)先行缺血预处理,再行缺血后处理,操作过程同IPr组和IPo组.于再灌注60 min时各组取肠粘膜组织,观察肠粘膜形态并行Chiu评分,检测丙二醛(MDA)含量,超氧化物歧化酶(SOD)及髓过氧化物酶(MPO)活性,同时采集动脉血样检测血浆肿瘤坏死因子α(TNF-α)及白细胞介素6(IL-6)浓度.结果 与S组比较,其余各组Chiu评分、MDA含量、MPO活性、血浆TNF-α与IL-6浓度升高,SOD活性降低(P<0.05).与IIR组比较,IPr组、IPo组及IPr-IPo组Chiu评分、MDA含量、MPO活性、血浆TNF-α和IL-6浓度降低.SOD活性升高(P<0.01).与IPr组和IPo组比较,IPr-IPo组Chiu评分和MDA含量降低,SOD活性升高(P<0.05).IPr组与IPo组各指标比较差异无统计学意义(P>0.05).结论 缺血预处理-后处理可减轻大鼠肠缺血再灌注损伤,较单独应用时效果好.     

黄芪甲苷预处理对大鼠肠缺血再灌注损伤的影响

目的:探讨黄芪甲苷(AS-Ⅳ)预处理对大鼠肠缺血再灌注损伤的影响。方法:30只成年雄性Wistar大鼠随机分为假手术(Sham)组、模型(I/R)组、AS-Ⅳ预处理(AS-Ⅳ)组。I/R组和AS-Ⅳ组采用无创微动脉夹夹闭肠系膜上动脉60 min再灌注120 min的方法建立大鼠肠缺血再灌注损伤模型。AS-Ⅳ组于造模前60 min时采用60 mg/kg AS-Ⅳ对大鼠进行灌胃预处理。于再灌注120 min时取小肠组织,采用HE染色法测定小肠组织病理学变化,ELISA法测定大鼠血清中TNF-α、HMGB-1、SOD和CAT的表达情况,荧光定量PCR法测定小肠组织中Bcl-2、Bax和Caspase-9的mRNA情况,Western blotting法测定小肠组织中紧密连接蛋白occludin和ZO-1的表达情况。结果:与Sham组比较,I/R组小肠组织病理学Chiu评分升高,TNF-α和HMGB-1的表达水平升高,SOD和CAT的表达水平降低,Bcl-2、Bax和Caspase-9的mRNA水平升高,occludin和ZO-1的蛋白表达水平降低(P0.05);与I/R组比较,AS-Ⅳ组I/R组小肠组织病理学Chiu评分降低,TNF-α和HMGB-1的表达水平降低,SOD和CAT的表达水平升高,Bcl-2、Bax和Caspase-9的mRNA水平降低,occludin和ZO-1的蛋白表达水平升高(P0.05)。结论:AS-Ⅳ灌胃预处理能够显著改善大鼠肠I/R损伤,其机制可能与减轻机体炎症反应和氧化应激水平、抑制肠道细胞的凋亡发生以及调节紧密连接蛋白表达有关。     

p38丝裂原活化蛋白激酶在肠缺血再灌注损伤大鼠炎性反应中的作用

目的探讨p38丝裂原活化蛋白激酶（p38MAPK）在肠缺血再灌注损伤大鼠炎性反应中的作用。方法健康成年雄性Wistar大鼠30只,随机分为3组（n=10）：假手术组（S组）、缺血再灌注组（I/R组）和p38MAPK抑制剂SB203580组（SB组）。采用夹闭肠系膜上动脉（SMA）的方法制备肠缺血再灌注损伤模型。I/R组和SB组夹闭SMA 1 h再灌注6 h,SB组缺血前30 min经股静脉注射p38MAPK特异性抑制剂SB203580 100μg/kg。于再灌注6 h时,处死大鼠,测定血浆肿瘤坏死因子-α（TNF-α）浓度、双胺氧化酶（DAO）活性及小肠组织TNF-α含量、p38MAPK、细胞间粘附分子-1（ICAM-1）表达水平,在光镜下观察小肠组织病理学,并进行小肠组织损伤程度评分。结果与S组比较,I/R组血浆TNF-α浓度、DAO活性及小肠组织p38MAPK、ICAM-1表达、TNF-α含量、小肠组织损伤程度评分升高,SB组血浆DAO活性、小肠组织ICAM-1表达、TNF-α含量及小肠组织损伤程度评分升高（P〈0.05）;与I/R组比较,SB组血浆TNF-α浓度、DAO活性及小肠组织p38MAPK、ICAM-1表达和TNF-α含量、小肠组织损伤程度评分降低（P〈0.05）。结论p38MAPK参与了肠缺血再灌注损伤大鼠炎性反应。     

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.