携带小鼠白介素12基因的增殖型腺病毒对胃癌细胞株化疗敏感性影响的研究

目的研究携带白介素12(mIL-12)基因的增殖型腺病毒CNHK200-mIL-12对胃癌细胞株化疗敏感性的影响。方法扩增增殖型腺病毒Onyx-015及携带小鼠mIL-12基因的增殖型腺病毒CNHK200-mIL-12,利用MTT法测定同一病毒滴度下联合应用不同浓度化疗药物及同一化疗药物浓度下联合应用不同滴度病毒对胃癌细胞株杀伤作用,并观察增殖型腺病毒联合化疗药物对裸鼠腹腔种植瘤的抑制作用。结果当不同感染复数(MOI)=0.5时,增殖型病毒Onyx-015、CNHK200-mIL-12对胃癌细胞SGC-7901无明显的杀伤作用。加入化疗药物阿霉素(ADM)、氟尿嘧啶(5-Fu)和卡铂(CAP)后,两者对SGC-7901的杀伤率随着药物浓度增加都有不同程度的升高,与单纯使用化疗药物组比较,差异有统计学意义(P<0.05)。浓度为10μg/ml的5-Fu对SGC-7901的杀伤作用不明显,单用增殖型腺病毒对SGC-7901的杀伤作用也较弱,两者联合应用杀伤活性明显提高,与未加5-Fu组比较,差异有统计学意义(P<0.05)。动物试验证明:经Onyx-015联合5-Fu治疗后,裸鼠腹腔内肿瘤形成率为1/6,而CNHK200-mIL-12联合5-Fu组未见腹腔内肿瘤生长,与单用增殖型腺病毒或单用化疗者比较,差异有统计学意义(P<0.05)。结论携带mIL-12基因的增殖型腺病毒能够提高胃癌细胞株对化疗药物的敏感性,在杀伤胃癌细胞株的作用中     

非增殖型和靶向增殖型腺病毒携带TRAIL基因治疗肝癌的实验研究

目的比较携带人TRAIL基因的增殖型腺病毒（CNHK500-hTRAIL）和非增殖型腺病毒（Ad-hTRAIL）对TRAIL基因的表达以及对SMMC-7721肝癌细胞的杀伤能力。方法通过病毒增殖实验评估增殖型腺病毒CNHK500-hTRAIL的选择性增殖能力。通过MTT实验,评估增殖型腺病毒CNHK500-hTRAIL以及非增殖型腺病毒Ad-hTRAIL对人正常肝细胞株L02、人肝癌细胞株SMMC-7721的杀伤能力。采用ELISA法检测CNHK500-hTRAIL和Ad-hTRAIL感染SMMC-7721肝癌细胞后TRAIL基因的表达情况。以及通过流式细胞术（FCM）检测其对细胞早期凋亡的影响。结果CNHK500-hTRAIL能选择性地在SMMC-7721细胞内大量增殖,感染96 h后增殖达225137倍,在极低的MOI值（MOI=0.1）即可大量杀伤SMMC-7721细胞,明显强于Ad-hTRAIL,而对L02细胞无明显杀伤。CNHK500-hTRAIL和Ad-hTRAIL感染SMMC-7721细胞后,其TRAIL基因表达量,前者是后者的近10倍;CNHK500-hTRAIL可选择性地诱导SMMC-7721细胞早期凋亡,其能力显著高于Ad-hTRAIL。结论靶向增殖型腺病毒载体携带TRAIL基因对肿瘤细胞的杀伤能力和目的基因的表达,明显优于传统的非增殖型腺病毒载体,应用前景广阔。     

基因-病毒治疗系统CNHK300-murine endostatin的构建及体外研究

目的构建一种新型的肿瘤基因．病毒治疗系统CNHK300-murine endostatin（CNHK300-mE），以肿瘤增殖病毒为载体，携带抗肿瘤新生血管生成的基因。方法利用基因重组技术将人端粒酶逆转录酶（hTERT）启动子插入腺病毒E1A基因上游，将小鼠内皮抑素基因表达盒插入到腺病毒包装信号和hTERT启动子之间，通过病毒增殖试验、电镜技术、Western blot分析、酶联免疫吸附实验（ELISA）、鸡胚绒毛尿囊膜（CAM）试验，观察CNHK300-mE的复制情况、mE的表达情况及对鸡胚绒毛尿囊膜新生血管的抑制情况。结果成功构建了基因-病毒治疗系统CNHK300-mE，该系统为hTERT启动子调控腺病毒E1A基因表达并携带小鼠内皮抑素基因的重组腺病毒。该病毒可以在端粒酶阳性的胃癌细胞株SGC-7901和肝癌细胞株HepGⅡ中大量增殖及复制，而在端粒酶阴性的正常纤维细胞中不增殖。电镜证实该重组病毒在胃癌细胞株SGC-7901中复制及增殖。ELISA检测表明SGC-7901感染CNHK300-mE后7d，小鼠内皮抑素的表达量为1000μg／L。CAM实验证实该病毒感染胃癌细胞后的培养液上清具有抗新生血管生成的生物活性。结论基因-病毒治疗系统CNHK300-mE能在端粒酶阳性的肿瘤细胞中特异性增殖复制，并大量表达具有抗新生血管生成生物活性的小鼠内皮抑素。     

多重调控病毒.基因载体的构建及其体外抗肿瘤活性

目的 构建一种新型的病毒.基因治疗载体.方法 通过克隆技术将人肿瘤坏死因子相关凋亡诱导配体(TRAIL)基因插入质粒载体pBHGE3的E3区,得到由主要晚期启动子(MLP)调控的腺病毒质粒pPE3-hTRAIL,再通过与质粒pSGS00在293细胞中进行位点特异性重组得到E1A、E1B基因分别受hTERT启动子与HRE启动子双重调控的重组增殖型腺病毒,用TCID50方法测定病毒滴度.通过增殖实验观察重组病毒的选择性增殖能力.利用酶联免疫吸附试验(ELISA)检测人TRAIL基因的表达.并进行噻唑蓝(MTT)比色法实验检测其杀伤肿瘤细胞的能力.结果 CNHK500-hTRAIL的病毒滴度为2.39×1010pfu/ml,增殖实验结果证实CNHK500-hTRAIL可以选择性地在端粒酶阳性的人肺癌细胞A549中增殖,其所携带的人TRAIL基因在A549中的表达量(183.12μg/L)明显高于携带该基因的非增殖型腺病毒载体Ad-hTRAIL(24.53μg/L,P<0.01).MTr显示CNHK500-hTRAIL对A549的杀伤能力明显高于携带该基因的非增殖型腺病毒载体Ad-hTRAIL,其半数抑制MOI值分别为17.825、0.197(P<0.01).结论 CNHKS00一hTRAIL是一种具备治疗肺癌潜力的新型病毒-基因治疗系统.     

携带治疗基因的增殖型腺病毒CNHK300-m干扰素-γ的构建

目的 研制出一种携带抗癌基因的选择增殖型腺病毒载体系统.方法 克隆鼠干扰素(IFN)-γ基因序列,利用分子克隆技术将其插入肿瘤特异性增殖病毒的病毒基因组中,得到腺病毒载体质粒pSG300-m IFN-γ.通过pSG300-m IFN-γ与质粒pBHGE3在293细胞中同源重组得到重组病毒CNHK300-mIFN-γ.扩增、纯化病毒,用TCID50方法测病毒滴度.通过病毒增殖实验观察重组病毒的选择性增殖能力,通过Western blot检测腺病毒蛋白的表达,通过双抗体夹心法酶联免疫吸附试验(ELISA)检测重组病毒在不同细胞及不同时相的mIFN-γ表达量.结果 成功构建了携带治疗基因的增殖型腺病毒CNHK300-mIFN-γ,病毒滴度为1.0×109 pfu/ml,增殖实验证实CNHK300-mIFN-γ可以选择性地在端粒酶阳性肿瘤中增殖,Western blot分析结果显示腺病毒的E1A蛋白选择性在端粒酶阳性的肿瘤细胞中表达,ELISA显示CNHK300-mIFN-γ感染端粒酶阳性肿瘤后有大量mIFN-γ的表达,并随着感染的时间表达量也相应上升.结论 CNHK300-mIFN-γ为肿瘤的生物治疗提供了一种新的策略.     

Ad.mda-7高选择性杀伤不同转移潜能肝癌细胞的研究

目的利用携带人MDA-7／IL-24基因的复制缺陷型腺病毒（Ad．mda7）作为载体，感染不同转移潜能的肝癌细胞MHCC97H，MHCC97L，Hep3B和正常的肝细胞L02，观察该基因对肝癌的选择性杀伤作用和增殖抑制作用。方法将携带人MDA-7／IL-24基因的腺病毒Ad．mda-7感染正常肝细胞L02和肝癌细胞MHCC97H，MHCC97L和Hep3B，通过RT-PCR和ELISA方法观察MDA7基因的表达，通过四甲基偶氮哩蓝染色法（MTT）观察该基因对肝癌细胞的生长抑制，Hoechst染色和流式细胞仪观察MDA-7对肝癌细胞的杀伤作用，流式细胞仪检测细胞周期变化。结果RT-PCR提示复制缺陷型腺病毒能介导外源基因MDA-7／IL-24在肝癌细胞株MHCC97H，MHCC97L，Hep3B和正常细胞L02中高效表达；ELISA方法检测提示细胞培养上清液中MDA-7／IL-24蛋白的表达，而且随着感染时间延长表达量升高；MTT实验结果表明MDA7能明显抑制肝癌细胞的生长，Hoechst染色和流式细胞仪提示MDA7能促进肝癌细的凋亡；细胞周期检测提示肝癌细胞大量被阻滞在G2／M期，正常细胞没有增殖阻滞作用。各项结果提示MDA7对正常的肝细胞没有促进凋亡和增殖阻滞的作用。结论Ad．mda-7选择性的杀伤肝癌细胞，促进细胞增殖阻滞及诱导肿瘤细胞凋亡与肝癌细胞的转移潜能无关。     

FasL、B7-1联合基因修饰的胃癌细胞诱导抗胃癌主动免疫的研究

目的 探讨FasL、B7-1联合基因转移是否具有协同的抗肿瘤效应。方法 采用重组腺病毒载体将FasL、B7-1基因导入人胃癌细胞SGC-7901,G418阳性克隆筛选,流式细胞分析,逆转录-聚合酶链反应(RT-PCR),显示FasL和B7-1的表达,并且通过Hoechst33342染色检测胃癌细胞凋亡;将携带 FasL和 B7-1基因的胃癌细胞(命名为 SGC-7901/FB-11)接种于 C57BL/6小鼠背部皮下,观测其致瘤性能;SGC-7901/FB-11致敏的小鼠对野生型瘤细胞是否具有免疫保护作用;用SGC-7901和 SGC-7901/FB-11细胞分别经腹腔免疫小鼠,得到腹腔浸润淋巴细胞及致敏脾细胞,MTT法检测其体外杀伤实验。结果 FasL和B7-1基因在胃癌细胞中获得高表达并可诱导胃癌细胞的凋亡,双基因转染的胃癌细胞的致瘤性明显下降;SGC-7901/FB-11诱导的细胞毒T淋巴细胞(CTL)对SGC-7901的杀伤活性显著高于野生型SGC-7901诱导的CTL对相同靶细胞的杀伤活性(P<0.05);SGC-7901/FB-11诱导的 CTL对 SGC-7901/FB-11的杀伤率显著高于对野生型 SGC-7901的杀伤率(P<0.05)。结论 FasL促进胃癌细胞凋亡,B7-1促进抗胃癌CTL的增殖、活化,在效应阶段两基因发挥着重要的协同作用。     

RhoC基因高表达对胃癌细胞血管内皮细胞生长因子、碱性成纤维细胞生长因子表达的影响

目的 探讨RhoC基因对胃癌细胞血管内皮细胞生长因子(VEGF)、碱性成纤维细胞生长因子(bFGF)表达的影响及其意义。方法 常规脂质体转染法将RhoC基因重组质粒转染人胃癌细胞系SGC7901；应用免疫细胞化学链霉菌抗生物素蛋白-过氧化酶(SP)法检测胃癌细胞转染RhoC基因重组质粒前后VEGF、bFGF蛋白表达的变化。结果 转染RhoC基因重组质粒在SGC7901细胞中有稳定表达。转染RhoC基因重组质粒SGC7901表达VEGF、bFGF明显强于对照组。结论 体外条件下RhoC基因可促进胃癌细胞VEGF、bFGF的表达。这可能是RhoC基因促进胃癌细胞侵袭、转移的分子基础。RhoC基因的表达可望作为估计胃癌转移的参考指标。     

基因-病毒治疗系统CNHK300-小鼠内皮抑素对裸鼠胃癌的抗肿瘤作用

目的探讨新构建的基因-病毒治疗系统CNHK300-小鼠内皮抑素murineendostatin（CNHK300-mE）对胃癌的抑制作用。方法通过胃癌SGC-7901细胞裸鼠皮下移植瘤模型观察该病毒治疗系统对胃癌生长和肿瘤血管生成的抑制作用。用电镜观察该病毒在肿瘤细胞中的复制情况及肿瘤细胞的超微结构改变。用酶联免疫吸附（ELISA）法检测mE基因在体内的表达。用免疫组织化学的方法检测腺病毒外壳蛋白六邻体（hexon）、增殖细胞核抗原（PCNA）及vWF因子相关抗原的表达情况。采用TUNEL法检测细胞凋亡。结果CNHK300-mE能在肿瘤细胞内复制,高表达mE,在第7天时,达到（2115±770）ng/ml（范围1745～3000ng/ml）;明显抑制胃癌皮下移植瘤的生长及瘤内的血管生成,并可引起胃癌细胞的凋亡[治疗组小鼠肿瘤细胞凋亡率（78.4±9.1）%,对照组仅（15.2±0.5）%,P〈0.01],抑制肿瘤细胞增殖[治疗组小鼠PCNA指数（55.0±1.4）%,对照组为（74.1±0.4）%,P〈0.05]。结论CNHK300-mE能在小鼠胃癌内增殖复制,高效表达mE基因,抑制胃癌生长。     

温热化疗诱导胃癌细胞凋亡及其对凋亡调控基因表达的影响

目的探讨温热化疗诱导不同分化程度胃癌细胞SGC7901和MKN45凋亡及其对凋亡调控基因表达的影响。方法体外培养中分化胃癌细胞SGC7901和低分化胃癌细胞MKN45并实施(43.0±0.1)℃温热化疗。用透射电子显微镜观察温热化疗后两种不同分化程度胃癌细胞的形态学改变。用末端原位标记法(TUNEL)测定肿瘤细胞的凋亡率。用流式细胞仪和Westernblot法分别测定凋亡调控基因Fas和bcl-2的表达水平。结果温热化疗诱导中分化胃癌细胞SGC7901凋亡的作用强于低分化胃癌细胞MKN45。温热化疗可诱导SGC7901凋亡调控基因Fas表达上调、bcl-2基因表达下调;但只诱导MKN45bcl-2基因表达下调,对MKN45Fas基因表达水平的影响不明显。结论温热化疗诱导分化较好的胃癌细胞的凋亡率大于低分化胃癌细胞;而Fas和bcl-2的表达水平可能是温热化疗后不同分化程度胃癌细胞凋亡率不同的重要原因。     

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.