脂多糖对U937细胞中microRNA-107与NF-κB信号通路的影响

目的分析单核细胞在炎症状态下microRNA-107与NF-κB信号通路的相关性。方法经50ng/ml佛波酯(PMA)诱导成熟的U937细胞随机分为对照组和LPS(10μg/ml)刺激组,LPS刺激时间为1、3、6h,采用qRT-PCR检测各组细胞中microRNA-107、肿瘤坏死因子α(TNF-α)、白细胞介素-1β(IL~(-1)β)的mRNA表达量;Western blot法检测细胞NF-κB(p65)与磷酸化p65(p-p65)蛋白含量。结果与对照组比较,LPS组细胞microRNA-107、TNF-α、IL~(-1)βmRNA表达量明显升高(P0.05);p-p65/p65蛋白含量比值明显升高(P0.01)。Spearman相关性分析显示,microRNA-107表达量与p-p65/p65蛋白含量比值呈中度正相关(r=0.69,P0.01);与TNF-αmRNA表达量(r=0.835,P0.01)、IL~(-1)βmRNA表达量(r=0.839,P0.01)呈高度正相关。结论脂多糖刺激PMA诱导的U937细胞后microRNA-107的表达升高可能与NF-κB信号通路有关。     

右美托咪定通过c-Fos/NLRP 3/caspase-1级联抑制LP S诱发的小胶质细胞炎症反应

目的探讨右美托咪定通过c-Fos/NLRP3/caspase-1级联抑制脂多糖(LPS)诱发的小胶质细胞炎症反应。方法选取新生的SD大鼠,取其小胶质细胞进行原代培养及分离纯化。采用LPS诱导建立小胶质细胞炎症模型。采用MTT法选取右美托咪定抑制LPS诱导小胶质细胞炎症反应的最适宜浓度。将细胞分为三组:对照组、LPS组和右美托咪定治疗组(D组)。采用实时定量PCR法测定细胞中IL-1β和TNF-α的mRNA表达量;采用ELISA法检测细胞上清液中IL-1β和TNF-α的含量;采用Western blot法检测原癌基因c-Fos、NLRP3和caspase-1的蛋白含量。结果与对照组比较,LPS组小胶质细胞中炎性因子IL-1β和TNF-α的mRNA表达量均明显升高(P0.05);D组IL-1β和TNF-α的mRNA表达量明显低于LPS组(P0.05)。与对照组比较,LPS组中小胶质细胞中炎性因子IL-1β和TNF-α的含量均明显增加(P0.05);而D组IL-1β和TNF-α的含量明显低于LPS组(P0.05)。与对照组比较,LPS组小胶质细胞中c-Fos、NLRP3和caspase-1的蛋白含量均明显增加(P0.01);而D组c-Fos、NLRP3和caspase-1的蛋白含量明显低于LPS组(P0.05)。结论右美托咪定可抑制LPS诱发的小胶质细胞中炎性因子IL-1β和TNF-α的mRNA表达量及蛋白含量,推测其作用机制可能与抑制c-Fos/NLRP3/caspase-1级联反应有关。     

丙泊酚对脂多糖诱导人单核细胞表达Peroxiredoxin-2蛋白和超氧化物歧化酶蛋白的影响

目的 研究丙泊酚对脂多糖(lipopolysaccharide,LPS)诱导人单核细胞(THP-1)表达Peroxiredoxin-2及超氧化物歧化酶(SOD1)的影响.方法 将体外培养的THP-1细胞按照完全随机方法分为4组:正常对照组(C组);LPS刺激组(L组):加入LPS 1 mg/L;丙泊酚处理组(P组):给予丙泊酚15 mg/L和丙泊酚预处理合并LPS刺激组(P+L组):给予丙泊酚15 mg/L,1 h后再给予LPS 1 mg/L.通过Western blot法分别检测各组内Peroxiredoxin-2及SOD1含量的变化,用四唑盐快速比色法(MTT)观察各组THP-1细胞的存活率.结果 在LPS刺激12 h后收集细胞,Westernblot结果显示与正常对照组(C组)、丙泊酚处理组(P组)、丙泊酚预处理合并LP3刺激组(P+L组)3组相比,LPS刺激组(L组)中Peroxiredoxin-2和SOD1的表达量明显降低,而L组与(P+L)组比较,(P+L)组中Peroxiredoxin-2和SOD1的表达量则明显高于L组;MTT结果显示L组与(L+P)组相比较,L组细胞存活率明显低于(L+P)组细胞存活率(P<0.05)结论丙泊酚可以逆转LPS对THP1细胞表达抗氧化蛋白Peroxiredoxin-2及SOD1的抑制作用,其抗氧化作用可能与增加Peroxiredoxin-2及SOD1的表达有关.     

丙泊酚对脂多糖诱导人单核细胞表达Peroxiredoxin-2蛋白和超氧化物歧化酶蛋白的影响

目的 研究丙泊酚对脂多糖(lipopolysaccharide,LPS)诱导人单核细胞(THP-1)表达Peroxiredoxin-2及超氧化物歧化酶(SOD1)的影响.方法 将体外培养的THP-1细胞按照完全随机方法分为4组:正常对照组(C组);LPS刺激组(L组):加入LPS 1 mg/L;丙泊酚处理组(P组):给予丙泊酚15 mg/L和丙泊酚预处理合并LPS刺激组(P+L组):给予丙泊酚15 mg/L,1 h后再给予LPS 1 mg/L.通过Western blot法分别检测各组内Peroxiredoxin-2及SOD1含量的变化,用四唑盐快速比色法(MTT)观察各组THP-1细胞的存活率.结果 在LPS刺激12 h后收集细胞,Westernblot结果显示与正常对照组(C组)、丙泊酚处理组(P组)、丙泊酚预处理合并LP3刺激组(P+L组)3组相比,LPS刺激组(L组)中Peroxiredoxin-2和SOD1的表达量明显降低,而L组与(P+L)组比较,(P+L)组中Peroxiredoxin-2和SOD1的表达量则明显高于L组;MTT结果显示L组与(L+P)组相比较,L组细胞存活率明显低于(L+P)组细胞存活率(P<0.05)结论丙泊酚可以逆转LPS对THP1细胞表达抗氧化蛋白Peroxiredoxin-2及SOD1的抑制作用,其抗氧化作用可能与增加Peroxiredoxin-2及SOD1的表达有关.     

丙泊酚对脂多糖诱导人单核细胞表达Peroxiredoxin-2蛋白和超氧化物歧化酶蛋白的影响

目的 研究丙泊酚对脂多糖(lipopolysaccharide,LPS)诱导人单核细胞(THP-1)表达Peroxiredoxin-2及超氧化物歧化酶(SOD1)的影响.方法 将体外培养的THP-1细胞按照完全随机方法分为4组:正常对照组(C组);LPS刺激组(L组):加入LPS 1 mg/L;丙泊酚处理组(P组):给予丙泊酚15 mg/L和丙泊酚预处理合并LPS刺激组(P+L组):给予丙泊酚15 mg/L,1 h后再给予LPS 1 mg/L.通过Western blot法分别检测各组内Peroxiredoxin-2及SOD1含量的变化,用四唑盐快速比色法(MTT)观察各组THP-1细胞的存活率.结果 在LPS刺激12 h后收集细胞,Westernblot结果显示与正常对照组(C组)、丙泊酚处理组(P组)、丙泊酚预处理合并LP3刺激组(P+L组)3组相比,LPS刺激组(L组)中Peroxiredoxin-2和SOD1的表达量明显降低,而L组与(P+L)组比较,(P+L)组中Peroxiredoxin-2和SOD1的表达量则明显高于L组;MTT结果显示L组与(L+P)组相比较,L组细胞存活率明显低于(L+P)组细胞存活率(P<0.05)结论丙泊酚可以逆转LPS对THP1细胞表达抗氧化蛋白Peroxiredoxin-2及SOD1的抑制作用,其抗氧化作用可能与增加Peroxiredoxin-2及SOD1的表达有关.     

盐酸戊乙奎醚对内毒素血症大鼠全身炎性反应的影响

目的 探讨盐酸戊乙奎醚对内毒素血症大鼠血清TNF-α、诱导型一氧化氮合酶(inducible nitric oxide synthase,iNOS),肺组织NF-κB亚基p65亲和肽(NF-κB p65)含量的影响. 方法 健康SD大鼠60只,采用随机数字表法分为5组(每组12只):对照组(C组)、内毒素组(LPS组)、LPS+低剂量盐酸戊乙奎醚组(P1组)、LPS+中剂量盐酸戊乙奎醚组(P2组)、LPS+高剂量盐酸戊乙奎醚组(P3组).LPS组腹腔注射内毒素8 mg/kg制备内毒素血症模型,C组给予等量生理盐水,P1组～P3组给予相应剂量的盐酸戊乙奎醚5 min后注射LPS,给药6h后处死动物取标本.采用ELISA检测血清TNF-α含量,采用比色法测血清iNOS活力,Western blot检测肺组织NF-κB p65含量,并观察肺组织病理学改变. 结果 与C组比较,LPS组、P1组、P2组、P3组血清TNF-α含量显著升高(P＜0.05),iNOS活力水平明显升高(P＜0.05),肺组织NF-κB p65表达明显增高(P＜0.05);与LPS组比较,P2组、P3组血清TNF-α、iNOS活力水平和肺组织NF-κB p65含量均下降(P＜0.05),而P1组TNF-α、iNOS活力和NF-κB p65表达水平,差异无统计学意义(P＞0.05);P2组、P3组间各指标表达水平比较,差异无统计学意义(P＞0.05);P2组、P3组肺组织病理学损伤程度明显轻于LPS组(P＜0.05). 结论 盐酸戊乙奎醚可能通过下调TNF-α、NF-κB p65的表达,减少iNOS活化来抑制内毒素休克大鼠全身炎症反应.     

转录因子核因子-κB p65通过miR-17调控血管平滑肌细胞增殖的机制研究

目的研究miR-17在血管平滑肌细胞(VSCM)增殖中的作用,以及转录因子核因子(NF)-κB调控miR-17的作用机制。方法将miR-17mimics转染人VSCM,CCK-8法检测细胞活力,流式细胞术检测细胞周期。生物信息学预测NF-κB p65与miR-17启动子区存在结合位点,将pcDNA3.1-p65与报告基因载体p GL3-miR-17启动子区共转染至293T细胞中,通过检测荧光素酶报告基因Luc活性分析NF-κB p65对miR-17启动子区的影响。脂多糖(LPS)刺激细胞后,检测NF-κB p65、miR-17的表达水平。结果与miR-NC组相比,转染miR-17 mimics后,VSMC增殖能力增强,差异具有统计学意义(P0.05),细胞周期G0/G1期明显减少,S与G2/M明显增加,差异具有统计学意义(P0.05)。与miR-17启动子区结合位点突变型(Mutant)组相比,转染miR-17启动子区野生型(Wild)组荧光素酶Luc活性增高,差异具有统计学意义(P0.05)。与对照组相比,LPS刺激细胞后,NF-κB p65、miR-17表达水平明显升高,差异具有统计学意义(P0.05)。结论 NF-κB通过直接结合miR-17启动子区,促进miR-17的表达从而促进VSMC的增殖。     

藁本内酯抑制星形胶质细胞中NF-κB依赖的细胞因子的表达

目的观察藁本内酯(LIG)对脂多糖(LPS)诱导的星形胶质细胞中促炎性细胞因子表达的抑制作用。方法将原代培养成功的星形胶质细胞随机分成四组,对照组(C组)、LPS组、LIG组、BAY组。C组未加入任何药物刺激细胞;LPS组加入浓度为1μg/ml的LPS刺激细胞6h;LIG组用浓度为50μM的LIG预孵育细胞30min后,再加入LPS刺激6h;BAY组用浓度为20μM的核转录因子(NF)-κB抑制剂BAY11-7082预孵育细胞30min后,再加入LPS刺激6h。采用Real-time PCR方法检测促炎性细胞因子白细胞介素(IL)-1β、肿瘤细胞坏死因子(TNF)-α、IL-6 mRNA的表达;采用Western blot方法检测pNF-κB p65的表达。结果与LPS组比较,C、LIG和BAY组IL-1β、TNF-α、IL-6mRNA的表达明显减少(P0.05)。与LPS组比较,C、LIG组pNF-κB p65蛋白的表达明显降低(P0.05)。结论藁本内酯可通过抑制原代培养的星形胶质细胞中NF-κB的活化来抑制LPS诱导的促炎症相关的细胞因子的表达。     

镧对内毒素/脂多糖诱导的巨噬细胞核因子KB活化的抑制作用

目的了解稀土元素镧对内毒素/脂多糖(LPS)诱导的小鼠腹腔巨噬细胞(Mφ)核因子κB(NF-κB)活化的影响,并探讨其机制。方法分离培养小鼠腹腔 Mφ,分为:空白对照组,无刺激因素;LPS 组,用1μg/ml LPS 刺激30 min;镧离子(La~(3 ))组,用2.5 μmol/L La~(3 )刺激30 min;La~(3 ) LPS 组,先后用2.5μmol/L La~(3 )、1μg/mI LPS 各刺激30 min;La~(3 )/LPS 组,2.5μmol/L La~(3 )刺激30 min 后,洗涤细胞,再加入1μg/ml LPS 刺激30 min。采用细胞免疫荧光染色法观察 NF-κB在各组细胞中的分布与表达;酶联免疫吸附测定(ELISA)法捡测胞核中 NF-κB/p65蛋白活性;蛋白质印迹法检测细胞核内 NF-κB/p65蛋白及胞质中核因子抑制蛋白α(IκBα)的表达量。ELISA 法测定各组细胞培养上清液中肿瘤坏死冈子α(TNF-α)的含量。结果 (1)免疫荧光染色显示,空白对照组、La~(3 )组、La~(3 ) LPS 组和 La~(3 )/LPS 组 Mφ绿色荧光多分布于胞质,胞核荧光强度分别为42±7、73±30、48±11和67±19;LPS 组绿色荧光集中于胞核,荧光强度为116±14,明显高于其余4组(P<0.01)。(2)胞核 NF-κB/p65蛋白活性:LPS 组吸光度值为0.435±0.066.与空白对照组(0.048±0.027)、La~(3 )组(0.062±0.049)、La~(3 ) LPS 组(0.066±0.031)、La~(3 )/LPS 组(0.108±0.017)比较,明显偏高(P<0.01)。(3)LPS 组 Mφ胞核 NF-κB/p65蛋白表达水平明显高于其余4组,胞质 IκBα蛋白表达水平明显低于其余4组。(4)TNF-α含量:La~(3 )组培养上清液中 TNF-α含量低于试剂盒检测下限(25 pg/ml)及空白对照组(P<0.05),La~(3 ) LPS 组和 La~(3 )/LPS 组低于 LPS 组(P<0.01),但高于空白对照组。结论 LPS 可激活小鼠腹腔 MφNF-κB/p65核移位,并使胞核中 NF-κB/p65的表达量和活性升高、胞质 IκBα蛋白表达下调,导致 TNF-α分泌增多。镧可抑制上述效应。     

异丙酚对LPS诱导BV-2小胶质细胞IL-1β和TNF-α释放的影响及TLR4在其中的作用

目的 评价异丙酚对LPS诱导BV-2小胶质细胞IL-1β和TNF-α释放的影响及Toll样受体4(TLR4)在其中的作用.方法 将体外培养的BV-2小胶质细胞接种于96孔培养板中,采用随机数字表法,将其随机分为4(n=12):对照组、LPS组、异丙酚组和LPS+异丙酚组.LPS组加入LPS1μg/ml孵育24h;异丙酚组加入异丙酚30 μmol/L孵育24 h;LPS+异丙酚组同时加入LPS 1 μg/ml和异丙酚30 μmol/L孵育24h.于孵育6h时,采用ELISA法检测细胞上清液TNF-α浓度,以此反映TNF-α的释放量,采用RT-PCR法测定TLR4 mRNA表达;于孵育24h时,采用ELISA法检测细胞上清液IL-1β浓度,以此反映IL-1β的释放量,采用Western Blot法检测TLR4蛋白表达.结果 与C组比较,LPS组和LPS+异丙酚组IL-1β和TNF-α的释放量升高,TLR4 mRNA及其蛋白表达上调(P＜0.05);与LPS组比较,LPS+异丙酚组IL-1β和TNF-α的释放量降低,TLR4 mRNA及其蛋白表达下调(P＜0.05).结论 异丙酚可抑制LPS诱导BV-2小胶质细胞IL-1β和TNF-α的释放,其机制与抑制TLR4的表达有关.     

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.     

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.     

Immunomodulation in Transplantation with Photopheresis

Abstract: Photopheresis is a technique in which peripheral blood mononuclear cells, in the presence of a photoacti-vatable compound, are exposed extracorporeally to ultraviolet A light and reinfused, inducing a host autoregula-tory immune response. Experimental work and ongoing clinical studies are helping to define the role of this novel, safe, and non-toxic immunomodulating technology in the field of transplantation.