大鼠心脏移植排斥反应时细胞间粘附分子-1的表达及霉酚酸酯对其的抑制作用

目的　探讨大鼠同种异位心脏移植排斥反应期间移植心组织细胞间粘附分子-1（ICAM-1）的表达及霉酚酸酯（MMF）对移植心ICAM-1表达和排斥反应的抑制作用。方法　建立大鼠心脏腹腔移植模型,设Wistar到Wistar大鼠的同系心脏移植对照组、SD大鼠到Wistar大鼠的同种移植组和同种移植MMF治疗组。采集移植心组织标本行免疫组织化学和组织病理学检查,应用多媒体彩色图文分析系统对移植心组织ICAM-1的表达进行定量检测。结果　对照组移植心组织ICAM-1表达较弱;同种移植组在排斥反应期间移植心组织毛细血管内皮细胞ICAM-1的表达强度和数量明显增加,且伴有大量淋巴细胞浸润;MMF治疗组移植心仅微弱表达ICAM-1,同时少有淋巴细胞浸润;检测移植心组织ICAM-1的表达改变比普通组织病理学检查可以提早2～3d发现排斥反应。结论　ICAM-1的表达水平与排斥反应的发生和发展有关;MMF能显著抑制移植心ICAM-1的表达和淋巴细胞的浸润,明显延长移植物的存活。     

细胞间粘附分子-1的反义寡核苷酸在异种心脏移植中的作用

目的探讨细胞间粘附分子1的反义寡核苷酸(ICAM1ASO)在小鼠→大鼠的异种心脏移植中对ICAM1表达以及排斥反应的作用。方法BALB/c小鼠和Lewis大鼠分别作为供者和受者,随机配对建立小鼠→大鼠的异种心脏移植模型。按照供者术前处理不同分为双蒸馏水对照组、寡核苷酸对照组和ICAM1ASO组。各组供者术前6h分别从右颈外静脉注射双蒸馏水、寡核苷酸和ICAM1ASO。术后48h各组取5只受者切取供心进行病理学检查;采用免疫组织化学方法对供心组织ICAM1的表达进行观察;半定量逆转录聚合酶链(RTPCR)法对ICAM1mRNA的表达进行定量分析。每组中余下5只受者继续观察直至供心停跳,记录供心存活时间。结果双蒸馏水对照组和寡核苷酸对照组在移植后48h可观察到供心心跳减慢,出现不同程度的心律不齐、心律紊乱,供心搏动无力;供心病理学检查显示心脏组织中广泛间质充血、水肿、出血及血栓形成,部分心肌髓样变性及溶解并伴有炎性细胞浸润;与移植前BALB/c小鼠心脏对比,内皮细胞和心肌细胞ICAM1表达明显增强;ICAM1mRNA表达也明显增加;供心存活时间分别为(53.6±3.58)h和(55.0±3.16)h。ICAM1ASO组供心ICAM1在蛋白水平和mRNA水平的表达均减弱;排斥反应程度也明显减轻;供心存活时间为(66.4±2.61)h;与寡核苷酸对照组和双蒸馏水对照组比较,差异有统计学意义。结论ICAM1ASO能明显抑制异种移植中供心ICAM1的表达,抑制异种移植后排斥反应的发生和发展,延长移植物的存活时间,其作用具有高度序列特异性。     

RNA干扰技术阻断CD40/CD40L共刺激通路对小鼠移植心存活时间的影响

目的 探讨慢病毒介导RNA干扰(RNAi)技术阻断CD40/CD40L共刺激通路对小鼠移植心存活时间的影响.方法 以针对小鼠CD40基因的RNAi慢病毒载体在体外感染供者骨髓来源的树突状细胞(DC),制备低表达CD40的耐受性DC(Tol-DC).荧光实时定量聚合酶链反应及流式细胞术检测DC感染前后CD40 mRNA及DC表面抗原CD40、CD11c和MHCⅡ的表达.建立小鼠异位腹腔心脏移植模型.在小鼠异位心脏移植前7 d,经静脉给受者输注体外制备的低表达CD40的Tol-EC(慢病毒感染DC注射组),并设置单纯移植对照组和未感染DC注射组作为对照.观察各组移植心的存活时间,评定各组术后第7天移植心排斥反应的病理分级.结果 CD40-RNAi慢病毒载体在体外感染DC 48 h后,CD40 mRNA表达明显受到抑制,抑制率为80.9%;CD40表达明显下降,由(74.37±4.08)%降至(40.07±4.03)%(P＜0.05).单纯移植对照组、未感染DC注射组和慢病毒感染DC注射组移植心存活时间分别为:(8±2)d、(9±1)d和(14±4)d,慢病毒感染DC注射组移植心存活时间明显延长,并且移植心排斥反应病理分级显著降低,差异有统计学意义(P＜0.05).结论 阻断CD40/C40L共刺激通路可抑制异系T淋巴细胞的活化,从而抑制急性排斥反应,延长小鼠移植心的存活时间.     

大鼠接受小鼠异种心脏移植后粘附分子ICAM-1的表达

目的观察大鼠接受小鼠异种心脏移植后延迟性排斥反应(DXR)的病理特征,研究异种心脏移植中粘附分子ICAM-1的表达变化,探讨DXR的发生机制。方法建立Lewis大鼠接受BALB/c小鼠异种心脏移植模型。随机将接受异种心脏移植的大鼠分为5组,每组5只,分别于移植后12、24、36、48 h及移植心停跳时切取移植心;另取5只术前健康雄性BALB/c小鼠心脏作为对照。进行病理学检查、免疫组织化学检测及图象分析定量,研究供者移植心组织中ICAM-1的表达,以及应用半定量逆转录-聚合酶链式(RT-PCR)方法检测移植心组织中ICAM-1 mRNA的表达。结果病理学检查显示移植后12 h,移植心组织中即有间质充血、出血以及少量的炎性细胞浸润;随时间的推移病变不断加重,直至排斥反应的终点呈现典型的DXR。术前对照组心脏组织中ICAM-1表达微弱;异种心脏移植后随着时间的推移,心脏组织中ICAM-1的表达不断增强。半定量RT-PCR结果显示,移植心组织中ICAM-1 mRNA亦随时间的推移进行性增高。结论异种心脏移植后,移植心组织中供者型ICAM-1的表达明显增强,与DXR的发生和发展密切相关;供者型ICAM-1表达增强可较早提示DXR的发生。     

槐耳清膏在小鼠心脏移植排斥反应中作用的初步探讨

目的 探讨槐耳清膏在小鼠心脏移植急性排斥反应中的作用.方法 实验分为3组:A组:同种异基因移植后槐耳清膏处理组(槐耳清膏组);B组:同种异基因移植财照组(移植排斥组)及C组:同系移植对照组(同系移植组).观察各组移植心脏的存活时间、术后第5天供心的组织病理改变.用免疫荧光检测移植心脏中CD8+T淋巴细胞的浸润和颗粒酶B的表达水平.结果 A组移植心脏的平均存活时间为(6.38±0.69)d,与B组(8.31±0.59)d相比明显缩短(P<0.01);心肌组织呈3级急性排斥反应病理改变,CD8+T淋巴细胞弥漫性浸润及颗粒酶B表达与两个对照组相比明显增强(P<0.05).结论 在术后早期单用槐耳清音会促进小鼠心脏移植物的急性排斥反应,可能机制足促进CD8+T淋巴细胞的组织浸润并增强颗粒酶B的表达.     

鼠纤维介素在小鼠心脏移植急性排斥反应中的表达及其意义

目的　探讨小鼠同种心脏移植急性排斥反应期间鼠纤维介素 (mfgl2 )在移植心脏组织中的表达及其与组织病理学改变的关系。方法　采用BALB/c小鼠到C5 7BL/ 6小鼠的颈部异位心脏移植作为同种排斥反应模型 ,以抗mgfl2多克隆抗体干预 ,并设同系小鼠心脏移植对照组。采集移植心组织标本作病理学检查 ,以免疫组织化学方法测定mfgl2在移植心脏组织细胞上的表达 ,并对mgfl2的表达进行半定量分析。结果　同系移植对照组移植心脏组织结构正常 ,未见mfgl2表达 ;同种移植组移植心脏组织出现进行性坏死 ,大量单个核细胞浸润 ,并伴有mfgl2的表达 ,且血管内皮细胞表达mfgl2 ;抗mfgl2抗体干预组移植心脏组织损伤较轻 ,移植物的存活时间延长 (P <0 .0 1) ,巨噬细胞、淋巴细胞的浸润和mfgl2表达量也显著减少。结论　mfgl2表达水平与排斥反应所致移植心脏病理损害程度相关 ;抗mfgl2抗体干预能显著减少移植心脏巨噬细胞、淋巴细胞的浸润 ,明显延长移植心脏存活时间。     

大鼠心脏移植排斥反应时细胞间粘附分了—1的表达及霉酚酯对其的抑制作用

目的 探讨大鼠同种异位心脏移植排斥反应期间移植心组织细胞间粘附分子－1（ICAM－1）的表达霉酚酯酯（MMF）对移植心ICAM－1表达和排斥反应的抑制作用。方法 建立大鼠心脏腹腔移植模型。设Wistar 到Wistar大鼠的同系心脏移植对照组、SD大鼠到Wistar大鼠的同种移植组和同种移植MMF治疗组。采集移植心组织标本行免疫组织化学和组织病理学检查,应用多媒体彩色图文分析系统对移植心组织ICAM－1的表达进行定量检测。结果 对照组移植心组织ICAM－1表达较弱;同种移植组在排斥反应期间移植心组织毛细血管内皮细胞ICAM－1的表达强度和数量明显增加,且伴有大量淋巴细胞浸润;MMF治疗组移植心仅微弱表达ICAM－1,同时少有淋巴细胞浸润;检测移植心组织ICAM－1的表达改变比普通组织病理学检查可以提早2－3d发现排斥反应。结论 ICAM－1的表达水平与排斥反应的发生和发展有关;MMF能显著抑制移植心ICAM－1的表达和淋巴细胞的浸润,明显延长移植物的存活。     

CXC趋化因子受体6在小鼠心脏移植排斥反应中的表达及意义

目的 研究CXC趋化因子受体6(CXCR6)在同种异体小鼠心脏移植中的表达及CXC趋化因子配体16(CXCL16)与CXCR6相互作用对移植物存活时间的影响.方法 以野生型Balb/c小鼠(H-2d)为供者(同种移植组),或以野生型C57BL/6小鼠(H-2b)为供者(同系移植组),以野生型C57BL/6小鼠为受者分别行小鼠腹腔异位心脏移植.测定同系和同种移植组小鼠移植心脏CXCR6mRNA的表达,并测定受者脾脏CD8+T淋巴细胞CXCR6的表达.另制作小鼠同种异位心脏移植模型(Balb/c小鼠为供者,C57BL/6小鼠为受者),将其分为实验组和对照组,实验组受者移植当天至发生排斥反应时腹腔注射抗CXCL16抗体,对照组受者同期注射对照抗体.记录两组移植心脏存活时间.进行CD8+T淋巴细胞的细胞毒试验,即用Balb/c小鼠脾细胞免疫C57BL/6小鼠后,获取C57BL/6小鼠脾脏CD8+T淋巴细胞,将Balb/c小鼠脾细胞与C57BL/6小鼠CD8+T淋巴细胞混合培养,分别加入抗CXCL16抗体、小鼠IgG(对照抗体)和抗CD40L抗体.结果 同种移植组移植心脏中CXCR6 mRNA的表达以及脾脏CD8+T淋巴细胞上CXCR6的表达均高于同系移植组和正常对照组.抗CXCL16抗体对CD8+T淋巴细胞的细胞毒活性无影响.与对照组相比较,实验组小鼠移植心脏存活时间并未明显延长.结论 小鼠心脏移植排斥反应中CD8+T淋巴细胞CXCR6的表达上升,阻断CXCL16/CXCR6相互作用并不能延长移植心脏的存活时间.     

CXC趋化因子受体6在小鼠心脏移植排斥反应中的表达及意义

目的 研究CXC趋化因子受体6(CXCR6)在同种异体小鼠心脏移植中的表达及CXC趋化因子配体16(CXCL16)与CXCR6相互作用对移植物存活时间的影响.方法 以野生型Balb/c小鼠(H-2d)为供者(同种移植组),或以野生型C57BL/6小鼠(H-2b)为供者(同系移植组),以野生型C57BL/6小鼠为受者分别行小鼠腹腔异位心脏移植.测定同系和同种移植组小鼠移植心脏CXCR6mRNA的表达,并测定受者脾脏CD8+T淋巴细胞CXCR6的表达.另制作小鼠同种异位心脏移植模型(Balb/c小鼠为供者,C57BL/6小鼠为受者),将其分为实验组和对照组,实验组受者移植当天至发生排斥反应时腹腔注射抗CXCL16抗体,对照组受者同期注射对照抗体.记录两组移植心脏存活时间.进行CD8+T淋巴细胞的细胞毒试验,即用Balb/c小鼠脾细胞免疫C57BL/6小鼠后,获取C57BL/6小鼠脾脏CD8+T淋巴细胞,将Balb/c小鼠脾细胞与C57BL/6小鼠CD8+T淋巴细胞混合培养,分别加入抗CXCL16抗体、小鼠IgG(对照抗体)和抗CD40L抗体.结果 同种移植组移植心脏中CXCR6 mRNA的表达以及脾脏CD8+T淋巴细胞上CXCR6的表达均高于同系移植组和正常对照组.抗CXCL16抗体对CD8+T淋巴细胞的细胞毒活性无影响.与对照组相比较,实验组小鼠移植心脏存活时间并未明显延长.结论 小鼠心脏移植排斥反应中CD8+T淋巴细胞CXCR6的表达上升,阻断CXCL16/CXCR6相互作用并不能延长移植心脏的存活时间.     

CXC趋化因子受体6在小鼠心脏移植排斥反应中的表达及意义

目的 研究CXC趋化因子受体6(CXCR6)在同种异体小鼠心脏移植中的表达及CXC趋化因子配体16(CXCL16)与CXCR6相互作用对移植物存活时间的影响.方法 以野生型Balb/c小鼠(H-2d)为供者(同种移植组),或以野生型C57BL/6小鼠(H-2b)为供者(同系移植组),以野生型C57BL/6小鼠为受者分别行小鼠腹腔异位心脏移植.测定同系和同种移植组小鼠移植心脏CXCR6mRNA的表达,并测定受者脾脏CD8+T淋巴细胞CXCR6的表达.另制作小鼠同种异位心脏移植模型(Balb/c小鼠为供者,C57BL/6小鼠为受者),将其分为实验组和对照组,实验组受者移植当天至发生排斥反应时腹腔注射抗CXCL16抗体,对照组受者同期注射对照抗体.记录两组移植心脏存活时间.进行CD8+T淋巴细胞的细胞毒试验,即用Balb/c小鼠脾细胞免疫C57BL/6小鼠后,获取C57BL/6小鼠脾脏CD8+T淋巴细胞,将Balb/c小鼠脾细胞与C57BL/6小鼠CD8+T淋巴细胞混合培养,分别加入抗CXCL16抗体、小鼠IgG(对照抗体)和抗CD40L抗体.结果 同种移植组移植心脏中CXCR6 mRNA的表达以及脾脏CD8+T淋巴细胞上CXCR6的表达均高于同系移植组和正常对照组.抗CXCL16抗体对CD8+T淋巴细胞的细胞毒活性无影响.与对照组相比较,实验组小鼠移植心脏存活时间并未明显延长.结论 小鼠心脏移植排斥反应中CD8+T淋巴细胞CXCR6的表达上升,阻断CXCL16/CXCR6相互作用并不能延长移植心脏的存活时间.     

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.     

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.     

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.     

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.