阻断转化生长因子-β1自分泌环对骨肉瘤细胞生物学活性和化疗药物敏感性的影响

目的　观察阻断转化生长因子 β1(TGF β1)自分泌环对肿瘤细胞增殖活性和化疗药物敏感性的影响。方法　将反义TGFβ1基因转染骨肉瘤细胞MG 63 ,采用四甲基偶氮唑蓝微量酶反应比色法 (MTT)检测细胞增殖活性。以含 0、0 .2 5、0 .5 0、0 .75、1.0 0mg/L阿霉素 (ADR)的培养基培养转染细胞 48h后 ,采用3 H TdR掺入法检测细胞化疗药敏感性。结果　MG 63和空载体转染细胞增殖活性为 0 .197± 0 .0 15和 0 .195± 0 .0 2 1,差异无显著性 (P >0 .0 5 )。反义TGF β1转染细胞增殖活性为 0 .162± 0 .0 17,生长明显缓慢 ,对ADR敏感性明显增强 ,与对照组比较差异有显著性 (P <0 .0 5 )。讨论　通过阻断TGF β1自分泌环以降低骨肉瘤表达TGF β1,可以抑制细胞增殖活性 ,增加细胞对化疗药敏感性     

转Endostatin基因角朊细胞移植对烧伤深Ⅱ°创面愈合及瘢痕增生的影响

目的探讨转内皮生长抑制素(ES)基因角朊细胞移植对烧伤深Ⅱ°创面愈合及瘢痕增生的影响。方法将人体皮肤移植于裸鼠并造成深Ⅱ°烧伤创面。实验分为对照组(11只)、单纯角朊细胞移植组及转ES基因角朊细胞移植组(各10只)。对照组不行细胞移植,创面自行愈合;单纯角朊细胞移植组创面移植培养人角朊细胞;转基因移植组移植转ES基因角朊细胞。观察各组裸鼠创面愈合特点、瘢痕增生情况,并对愈合区组织进行病理切片检查、检测愈合区皮肤组织ES 蛋白表达、I、Ⅲ型前胶原含量。结果转基因移植组裸鼠创面愈合时间(13±5)d与单纯移植组 (14±5)d差异无统计学意义(P>0．05),但明显短于对照组[(25±7)d,P<0．01]。对照组裸鼠创面愈合后瘢痕增生明显,伤后100 d厚度≥0．22 cm,单纯移植组瘢痕增生厚度≥0．17 cm,转基因移植组仅有轻度瘢痕增生,愈合区皮肤组织ES蛋白检测阳性。单纯移植组、转基因移植组愈合区组织前胶原I含量(65．3±8．5)μg／g,(61．4±7．0)μg／g、前胶原I／前胶原Ⅲ比例(0．66±0．15,0．57± 0．13)明显低于对照组(1．51±0．37,P<0．01),而前胶原Ⅲ含量显著高于对照组(P<0．01)。结论转ES基因移植既可加速创面封闭,又能抑制愈合后瘢痕形成。     

雌激素对大鼠门静脉高压性胃病的影响及其机制

目的探讨雌激素对大鼠门静脉高压性胃病的影响及其机制。方法40只SD大鼠被随机分为4组:P+E组接受门静脉主干结扎+雌激素;P组仅接受门静脉主干结扎;S+E组接受假手术+雌激素;S组仅接受假手术。所有大鼠维持相应处理14 d后处死,处死前1h予2 ml 99％乙醇灌胃。用激光多普勒仪检测胃黏膜血流量,计算胃黏膜损伤程度。用动态一氧化氮(NO)检测仪检测胃黏膜NO含量等。结果P+E组胃黏膜血流量(103±14)U显著高于其他3组(P<0．05)。胃黏膜损伤指数:P+E组(0．28±0．17)、P组(0．21±0．08)和S+E组(0．21±0．12)组均显著高于S组(0．11±0．06),P<0．05。P+E组的NO测量值(153±23)nmol／L显著高于P组(123±14) nmol／L、S+E组(116±18)nmol／L和S组(104±15)nmol／L,P<0．05。结论雌激素加重门静脉高压症大鼠胃黏膜的损伤,可能与其促进胃黏膜内NO的产生有关。     

联合反义存活素、血管内皮生长因子治疗裸鼠骨肉瘤

目的探讨存活素（Survivin，SVV）、血管内皮生长因子（VEGF）反义寡核苷酸（ASODN）联合治疗裸鼠骨肉瘤。方法构建荷骨肉瘤裸鼠模型，采用瘤内注射给药方式（5mg,／kg体重），以反义SVV、反义VEGF对瘤鼠进行联合干预治疗1周，并与各单药组和空白对照组进行比较，观测各组裸鼠肿瘤生长情况、评估瘤体病理形态，免疫组织化学法检测移植瘤组织SVV、VEGF蛋白表达，DNA末端原位标记法（TUNEL法）检测肿瘤细胞凋亡水平。结果与对照组比较，各治疗组肿瘤生长均不同程度受抑，以联合组最为显著，瘤重仅为（0．52±0．01）g，抑瘤率IR为（42．80±0．88）％；各治疗组肿瘤细胞中SVV、VEGF蛋白表达有所减低，肿瘤细胞出现凋亡坏死改变，其中联合组细胞凋亡指数AI[（27．90±3．66）％]显著高于对照组[（7．10±2．05）％，Χ^2=46．27，P〈0．01]。结论联合应用SVV与VEGFASODN将对裸鼠荷骨肉瘤发挥更强的抗瘤效应。     

增殖性腺病毒CNHK600-p53的构建及对肝癌细胞抑制的体外实验研究

目的研究携带p53基因的新型增殖性腺病毒CNHK600-p53的导入是否增加肝癌细胞株PLC／PRF5对化疗药物的敏感性。方法采用四甲基偶氮唑盐(methylthiazolyl tetrazolium assay,MTT)法,观察化疗药物5-氟尿嘧啶(Fluorouracil,5-Fu)、丝裂霉素(Mitomycin,MMC)和表阿霉素(Epirubicin,EPI)单独及与CNHK600-p53联合对肝癌细胞株PLC／PRF5的杀伤效应。结果PLC／PRF5在5-Fu浓度为400μg／ml时细胞抑制率为(65±4．2)％,MMC浓度为1μg／ml细胞抑制率为(41±1．9)％,EPI浓度为10μg／ml细胞抑制率为(65±1．8)％。转入CNHK600-p53(MOI= 0．625)后再使用上述浓度的化疗药物,细胞抑制率分别为(89±5．3)％、(60±2．3)％和(75±1．5)％。当MOI值为0．3125,0．625,1．25时,CNHK600-p53组和Ad-p53组的细胞抑制率分别为(27±2．5)％、(30±3．7)％、(61±4．3)％和(4±2．7)％、(5±3．5)％、(16±4．5)％。结论单用CNHK600-p53效果优于Ad-p53,携带p53基因的CNHK600-p53能提高肝癌细胞株PLC／PRF5对化疗药物的敏感性。     

外磁场协同表阿霉素-羧甲基磁性纳米颗粒对膀胱癌体内外的杀伤作用

目的探讨脉冲外电磁场协同表阿霉素(EPI)-羧甲基葡聚糖氧化铁磁性纳米颗粒(CDMN)对人膀胱癌BIU-87细胞体外增殖活性和裸鼠皮下移植膀胱癌生长及其凋亡的影响。方法用化学共沉淀和氧化还原法制备EPI-CDMN并检测其理化性质,建立膀胱癌BIU-87细胞裸鼠皮下移植瘤动物模型,并设立空白对照组、磁场组、EPI组和EPI-CDMN组作为对照。分别采用噻唑蓝(MTT)比色法、双标流式细胞术、DNA原位末端标记法观察脉冲外电磁场联合EPI-CDMN对BIU-87细胞生长增殖活性和裸鼠皮下瘤生长状况及凋亡的影响。结果EPI-CDMN的直径、比饱和磁化强度分别为8～10 nm、0．22 emu/g。外磁场协同EPI-CDMN可以显著抑制BIU-87细胞增殖,抑制率达(21．82±3．18)%,并诱导细胞发生明显的凋亡,凋亡率为(16．8±3．4)%,均显著高于其他各组(P＜0．05)；裸鼠皮下瘤体积(1．57±0．42)cm~3和重量(2．00±0．21)g,均显著低于其他各组,抑瘤率51．69%和细胞凋亡指数(60．45±6．93)%均明显高于其他各组。结论外磁场可以显著增强EPI-CDMN对膀胱肿瘤的杀伤作用,为抗膀胱肿瘤的磁靶向治疗提供了实验依据。     

聚乙二醇化干扰素-α联合卡培他滨对肝癌生长作用的影响

目的探讨联合应用聚乙二醇化干扰素-α与肿瘤选择性化疗药卡培他滨抑制肝癌生长的作用。方法用30只LCI-D20人肝癌高转移裸鼠模型,随机分为对照组、聚乙二醇化干扰素- α组(1．875μg／周)、卡培他滨组(每日2．10mmol／kg体重)和联合用药组。用药4周后,观察裸鼠肝内移植瘤体积变化及肝内转移情况,检测血常规、肝肾功能和体重变化。结果对照组、聚乙二醇化干扰索-α组、卡培他滨组和联合用药组肿瘤体积分别为(2 275±1 337)、(336±220)、(889±614) 和(26±56)mm~3。与对照组相比,用药组肿瘤体积明显缩小,联合用药组尤为突出(P<0．01)。各用药组血常规、肝功能和体重的变化差异无统计学意义(P>0．05)。结论聚乙二醇化干扰素-α与卡培他滨联合应用能显著抑制LCI-D20裸鼠模型中肝移植瘤的生长和浸润,副作用不明显。     

维拉帕米对脑膜瘤细胞增殖的抑制作用

目的探讨维拉帕米对脑膜瘤细胞增殖的影响。方法将不同浓度维拉帕米作用于培养的脑膜瘤细胞,MTT法观察其对细胞增殖的抑制作用。建立裸鼠皮下脑膜瘤模型,观察服用维拉帕米后肿瘤的生长情况,免疫组织化学检测皮下肿瘤增殖细胞核抗原(PCNA)的表达。结果维拉帕米呈浓度依赖性地抑制脑膜瘤细胞增殖,浓度为1 μmol／L时即有抑制效应,抑制率为 16．82％,100μmol／L时抑制作用最明显,为52．95％。服药组皮下肿瘤体积明显小于对照组 (163．94±10．24 VS 211．40±16．51,P<0．01),其PCNA表达也低于对照组(1．52±0．24 VS 2．86±0．53,P<0．05)。结论维拉帕米在体外和体内均可抑制脑膜瘤细胞的增殖和生长。     

左旋卡尼汀对离体心肌缺血再灌注损伤的保护作用

目的探讨左旋卡尼汀增补于停搏液中对离体鼠心再灌注损伤的保护作用。方法将32只SD大鼠随机分为左旋卡尼汀3个剂量(2．5、5．0、10．0 mmol／L)组和对照组。离体鼠心在改良的Langendorff灌注模型上30 min预灌注,120 min缺血、60 min再灌注。缺血前及再灌注期间测定血流动力学指标、心肌超氧化物歧化酶(SOD)、丙二醛(MDA)含量和三磷酸腺苷(ATP)水平。电镜观察心肌超微结构。结果再灌注60 min后,左旋卡尼汀5 mmol／L剂量组和10 mmol／L剂量组与对照组相比,冠脉流量(CF)[(68．39±12．71)％、(72．27±6．27)％比(44．94±13．26)％]、左室收缩压(LVSP)[(73．04±3．32)％、(77．8±3．80)％比(62．29±4．14)％]、左室舒张末压(LVEDP)[(0．38±0．01)、(0．36±0．01)比(0．43±0．01)mmHg(1mmHg=0．133 kPa)]、左室压力变化速率(+dp／dt)[(69．66±0．92)％、(71．34±0．66)％比(62．16±1．21))％]、(-dp／dt) [(68．39±12．71)％、(72．27±6．27)％比(44．94±13．26)％],其差异均有统计学意义(P＜0．01)。心肌超微结构的改善,也优于对照组,尤其是10 mmol／L剂量组,2．5 ml／L组没有变化。左旋卡尼汀5 mmol／L剂量组和10 mmol／L剂量组丙二醛(MDA)含量显著低于对照组(19．04±0．41)、(17．60±0．53)nmol／mg蛋白比(27．36±1．23)nmol／mg蛋白,P＜0．01),超氧化物歧化酶(SOD) [(218．20±14．91)、(238．63±7．61)U／mg蛋白比(141．80±15．17)U／mg蛋白]含量和三磷酸腺苷(ATP)水平[(3．83±0．20)、(5．26±0．18)μmol／L比(1．36±0．08)μmol／L]显著高于对照组(P＜0．01)。结论左旋卡尼汀(5～10 mmol／L)增补于停搏液中可减轻心肌缺血再灌注损伤,具有良好的心肌保护作用并在一定范围内呈剂量依赖性,10mmol／L剂量组心肌保护效果最佳。     

靶向丝氨酸/苏氨酸激酶15基因小片段干扰RNA抑制胃癌细胞生长的实验研究

目的观察丝氨酸／苏氨酸激酶15基因(serine／threonine kinase15,STK15)沉默后对胃癌细胞系MKN45体内外生长的抑制作用,探讨STK15基因作为胃癌靶点治疗的可行性。方法应用RNA干扰技术(RNA interference,RNAi)抑制STK15基因的表达;Western blot检测STK15蛋白质的表达变化;体外侵袭实验检测MKN45细胞侵袭能力的变化;MTT法检测MKN45细胞增殖速度的变化。将裸鼠随机分成2组,每组10只,皮下移植经STK15siRNA处理的MKN45细胞,观察其成瘤性的改变。结果 MKN45细胞经STK15 siRNA作用后,蛋白表达水平均明显降低;STK15-组与对照组比较体外侵袭能力明显下降[平均4值为(182±27)比(308±38),P<0．05];更多的MKN45 细胞聚集于G2／M期附近[G2期DNA含量细胞为(30±5)％比(14±3)％,P<0．05];增殖速度明显减缓(P<0．05);在裸鼠体内成瘤性明显减低[平均肿瘤重量为(0．15±0．07)g比(0．29±0．16)g, P<0．05]。结论靶向STK15的siRNA可在体内外抑制胃癌MKN45细胞的增殖,STK15有可能成为胃癌治疗的靶点。     

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.