异丙酚对LPS诱导中性粒细胞Toll样受体2和Toll样受体4表达的影响

目的 探讨异丙酚对内毒素(LPS)诱导中性粒细胞Toll样受体2(TLR2)和TLR4表达的影响.方法 健康志愿者6名,年龄20～35岁,各采集外周静脉血样50 ml,加入20 U/ml肝素抗凝,分离提纯中性粒细胞,制备细胞悬液,然后随机分为6组,每组6皿:对照组(C组)不给予任何药物,置于37℃、5%CO_2培养箱中培养12 h;异丙酚脂质溶剂intralipid组(I组)、异丙酚组(P组)和LPS组(L组):分别加入intralipid(终浓度为5 μg/ml)、异丙酚(终浓度为5 μg/ml)或LPS(终浓度为1μg/ml),置于37℃、5%CO_2培养箱中孵育12 h;intralipid+LPS组(IL组)和异丙酚+LPS组(PL组)先分别加入intralipid(终浓度为5 μg/ml)或异丙酚(终浓度为5 μg/ml)后,置于37℃、5%CO_2培养箱中孵育20 min,然后加入LPS(终浓度为1μg/ml),置于37℃、5%CO_2培养箱孵育12 h.采用流式细胞仪测定中性粒细胞膜TLR2和TLR4的表达;采用荧光定量PGR检测中性粒细胞膜TLR2 mRNA和TLR4 mRNA的表达;采用ELISA法测定培养上清液TNF-α和IL-8的浓度.结果 与C组比较,I组和P组TLB2和TLR4的表达、1NF-α和IL-8L-8的浓度差异无统计学意义(P>0.05),L组和IL组TLR2和TLR4的表达上调,L组TNF-α和IL-8L-8的浓度升高,IL组IL-8浓度升高(P<0.05);与L组比较,IL组TLR2和TLR4的表达、TNF-α和IL-8L-8的浓度差异无统计学意义(P>0.05),PL组TLR2和TLR4的表达下调,TNF-α和IL-8L-8的浓度降低(P<0.05).各组TLR2 mRNA和TLR4 mRNA的表达差异无统计学意义(P>0.05).结论 异丙酚可下调LPS诱导的中性粒细胞TLR2和TLR4的表达,从而抑制炎性反应.     

异丙酚对肿瘤坏死因子-α诱导小鼠脊髓神经元凋亡的影响

目的研究异丙酚对肿瘤坏死因子-α（TNF-α）诱导小鼠脊髓神经元凋亡的影响。方法脊髓神经元取自孕14d胎龄小鼠的胎鼠，于含B27的神经细胞培养基中培养7d后，随机分为6组：对照组（Con组）；50μmol／L异丙酚组（P50组）；TNF-α组（TNF-α组）；25μmol／L异丙酚＋TNF-α组（P25＋TNF-α组）；50μmol／L异丙酚＋TNF-α组（P50＋TNF-α组）；100μmol／L异丙酚＋TNF-α组（P100＋TNF-α组），各组中加入相应终浓度的异丙酚孵育30min，再加入TNF-α至终末浓度为2000U／ml，培养24h后，采用碘化丙锭／Hoechst 33342双染法检测细胞凋亡，计算细胞凋亡率，采用免疫细胞化学方法测定Bcl-2表达。结果与Con组比较，TNF-α组神经元凋亡率升高，Bcl-2表达降低（P〈0．01），不同浓度异丙酚预先给药可减弱TNF-α诱导的上述改变（P〈0．05）。结论异丙酚可抑制TNF-α诱导小鼠脊髓神经元的凋亡，其机制与上调Bcl-2表达有关。     

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.     

右美托咪啶对脂多糖诱导大鼠外周血单核细胞Toll样受体4mRNA表达的影响

目的 探讨右美托咪啶对脂多糖(LPS)诱导大鼠外周血单核细胞Toll样受体4(TLR4)mRNA表达的影响.方法 健康雄性Wistar大鼠40只,取外周血分离培养单核细胞,采用随机数字表法,将其随机分为5组(n=8),A组:阴性对照;B组:单核细胞中加入LPS(终浓度为1μg/ml);C组:单核细胞中加入LPS(终浓度为1μg/ml)+右美托咪啶(终浓度为0.5 ng/ml);D组:单核细胞中加入LPS(终浓度为1μg/ml)+右美托咪啶(终浓度为5.0 ng/ml);E组:单核细胞中加入LPS(终浓度为1μg/ml)+右美托咪啶(终浓度为50.0 ng/ml).孵育24 h后,收集上清液,采用ELISA法测定TNF-α、IL-1β和IL-6的浓度,采用RT-PCR法测定TLR4 mRNA的表达.结果 与A组比较,B组TNF-α、IL-1p、IL-6的浓度升高,TLR4 mRNA表达上调(P＜0.01);与B组比较,C组、D组和E组TNF-α、IL-1β、IL-6的浓度降低,TLR4 mRNA表达下调(P＜0.05或0.01);与C组比较,D组和E组TNF-α、IL-1β、IL-6的浓度降低(P＜0.01),TLR4 mRNA表达差异无统计学意义(P＞0.05);D组和E组各指标比较差异无统计学意义(P＞0.05).结论 右美托咪啶可通过下调TLR4 mRNA表达,抑制TLR4的合成,从而抑制LPS诱导大鼠外周血单核细胞TNF-α、IL-1β和IL-6的生成与释放.

Abstract：

Objective To investigate the effects of different concentrations of dexmedetomidine on the expression of Toll-like receptor 4 (TLR4) mRNA in rat peripheral blood monocytes exposed to lipopolysaccharide ( LPS ). Methods Peripheral blood monocytes isolated from male Wistar rats were seeded in 24-well plate in RPMI 1640 liquid culture medium in CO2 incubator at 37 ℃ and 5% CO2 for 2 h, and were randomly divided into 5 groups ( n = 8 each): group A negative control; group B was exposed to LPS 1 μg/ml and C, D and E groups were exposed to LPS 1 μg/ml + dexmetomidine 0.5, 5.0 and 50.0 ng/ml respectively. The monocytes were then incubated for 24 h. The concentrations of TNF-α, IL-1β and IL-6 in the supernatant of the cultured monocytes were detected by ELISA. The expression of TLR4 mRNA in the monocytes was detected by RT-PCR.Results Exposure to LPS significantly increased the expression of TLR4 mRNA and the concentrations of TNF-α, IL-1β and IL -6 in group B as compared with group A ( P ＜ 0.01 ). Dexmedetomidine attenuated the LPS-induced increase in the expression of TLR 4 mRNA and the concentrations of TNF-α, IL-1β and IL-6 in a dose-dependent manner ( P ＜0.05or 0.01 ). Conclusion Dexmedetomidine can inhibit the synthesis of TLR4 and inhibit the secretion and dilivery of TNF-α, IL-1β and IL-6 by down-regulating the gene expression of TLR4 in rat peripheral blood monocytes exposed to LPS.     

交感神经递质NE对内毒素诱导大鼠kupffer细胞TNF-α/IL-1β表达的影响

目的探讨交感神经递质去甲肾上腺素对体外培养大鼠kupffer细胞TNF-α、IL-1β炎症相关细胞因子表达的影响。方法分离大鼠kupffer细胞体外分三组培养,经体外培养48h后,给予外源性内毒素（LPS10μg／m1）刺激,同时给予不同浓度的去甲。肾上腺素（0．1μmol／L～10μmol／L）分别作用12h,运用定量逆转录多聚酶链反应检测各处理组TNF-α和IL-1β mRNA的表达,ELISA检测细胞培养上清TNF-α IL-1β蛋白的表达。结果同时给予LPS（10μg/ml）刺激和去甲肾上腺素（1μmol／L及10μmol／L）作用后,kupffer细胞培养上清TNF-α和IL-1β蛋白较LPS组显著增高（P〈0．05）;TNF-α mRNA表达分别较LPS组增加50．9％（P〈0．05）和59．1％（P〈0．05）;IL-1β mRNA较LPS组表达增加53．7％（P〈0．05）和57．8％（P〈0．05）。结论应激浓度的去甲肾上腺素能增加内毒素诱导大鼠kupffer细胞TNF-α、IL-1β表达,具有促炎效应。     

脂氧素A4对脂多糖活化小鼠巨噬细胞NF-κB和TNF-α转化酶的影响

目的 研究脂氧素A4（LXA4）对脂多糖（LPS）活化的小鼠巨噬细胞NF-κB及TNF-α转化酶的影响。方法 小鼠RAW 264．7巨噬细胞株培养于细胞培养板,随机分为空白对照组、LPS处理组（LPS 1μg/ml）和LPS＋LXA4组（LPS 1μg/ml＋LXA4 10^-7mol/L）。酶联免疫吸附法测定上清液TNF-α水平,提取细胞总蛋白,Western blot法测定NF-κB p65、IκB-α及TNF-α转化酶含量,荧光素酶报告质粒测定NF-κB活性。结果 LXA4抑制LPS活化的RAW 264．7巨噬细胞IκB-α降解、NF-κB p65核转位及NF-κB活性,同时抑制TNF-α蛋白表达和上调TNF-α转化酶蛋白表达。结论 LXA4通过抑制NF-κB活性和下调TNF-α转化酶表达而减少LPS活化的RAW264．7巨噬细胞分泌TNF-α。     

LPS耐受巨噬细胞致炎和抗炎细胞因子表达和分泌的特点

目的：分析巨噬细胞LPS耐受形成过程中致炎和抗炎细胞因子（TNF-α、IL-6和IL-10）释放的特点和规律,探讨其在巨噬细胞建立LPS耐受机制中的作用.方法：培养小鼠腹腔巨噬细胞系RAW264.7 细胞.实验分为两部分：①LPS刺激细胞不同时间（4 h,8 h,20 h）或用PBS培养细胞4 h;②LPS耐受实验（LPS预刺激巨噬细胞20 h后,换液并洗去LPS,再次加入LPS刺激4 h）.ELISA法检测细胞培养上清中TNF-α、IL-6和IL-10的浓度,RT-PCR法相对定量分析巨噬细胞TNF-α和IL-10 mRNA 表达水平.结果：细胞培养上清中TNF-α、IL-6和IL-10的浓度随着LPS刺激时间的延长而增加;LPS刺激20 h后建立耐受的巨噬细胞再次受到LPS打击时,其TNF-α释放量低于非耐受细胞,而IL-6和IL-10释放量则大幅增加,与TNF-α释放减少截然相反.TNF-α和IL-10mRNA 表达水平与其蛋白分泌量呈现相似的变化规律.结论：巨噬细胞对LPS的耐受建立在致炎因子和抗炎因子共同作用的基础上;LPS预刺激细胞再次受到LPS打击时,抑炎因子表达和分泌大幅增加是介导巨噬细胞对LPS耐受的重要机制.     

硫喷妥钠对内毒素诱导小鼠肺组织NF-κB表达的影响

目的研究硫喷妥钠对内毒素（LPS）诱导小鼠肺组织NF-κB的表达的影响。方法雄性昆明小鼠24只，随机分为4组（n=6）：对照组（C组）、LPS组（L组）、硫喷妥钠处理组（L＋T组）、单纯硫喷妥钠处理组（T组）。C组腹腔注射生理盐水1ml／ks；L组腹腔注射LPS5mg／kg；L＋T组腹腔注射LPS5mg／kg 20min时再注射1％硫喷妥钠注射液60mg/kg；T组单纯腹腔注射1％硫喷妥钠注射液60mg／kg。在注射LPS后3h放血处死小鼠，立即开胸取肺。免疫蛋白印迹法测定肺组织NF-κB p65的表达；酶联免疫吸附法测定肺组织肿瘤坏死因子-α（TNF-α）、白细胞介素-1β（IL-1β）含量。结果与C组相比，L、L＋T组肺组织NF-κB p65表达增加，L、L＋T、T组肺组织，TNF-α、IL-1β含量上升（P〈0．05）；与L组相比，L＋T、T组肺组织NF-κB p65表达降低，肺组织TNF-α，IL-1β含量降低（P〈0．05）。结论硫喷妥钠通过下调小鼠LPS诱导的肺组织NF．KB065表达，降低了TNF-α及IL-1β的释放。     

依那西普对磨屑诱导骨溶解影响的实验研究

[目的]检测依那西普（Etanercept，Enbrel）对钛颗粒刺激巨噬细胞（macrophages，MФ）分泌肿瘤坏死因子α（tumor necrosis factor-α，TNF-α）、白介素1（interleukin-1，IL-1）、白介素6（interleukin-6，IL-6）的影响，探讨依那西普防治人工关节无菌性松动的可能性。[方法]分离、培养小鼠腹腔巨噬细胞，24h后分为5组。A组：仅为MФ；B组：MФ＋钛颗粒；C组：MФ＋钛颗粒＋依那西普（10ng／m1）；D组：MФ＋钛颗粒＋依那西普（100ng／ml）；E组：MФ＋钛颗粒＋依那西普（1000ng／ml）。培养18h后，用酶联免疫法（ELISA）检测细胞培养上清液中TNF-α、IL-1、IL-6的含量。[结果]B组TNF-α、IL-1、IL-6含量明显高于A、D、E组（P〈0．001），E组TNF-α、IL-1、IL-6的含量明显低于B组、C组（P〈0．001，E组和D组间无统计学意义（P〉0．05）。[结论]钛颗粒可以刺激MФ分泌大量的TNF-α、IL-1、IL-6，依那西普能够呈剂量依赖型地有效抑制钛颗粒诱导的MФ分泌TNF-α、IL-1、IL-6，有望成为预防人工关节无菌性松动的药物。     

复肾颗粒对脂多糖诱导下人肾小管上皮细胞TRAF6表达的影响

目的:探讨复肾颗粒含药血清对脂多糖(L)诱导下人肾小管上皮细胞(HK-2)的增殖及肿瘤坏死因子受体相关因子6(TRAF6)表达的影响。方法:体外培养HK-2细胞并制备复肾颗粒含药血清,分为正常组,LPS诱导组(10μg/ml)、对照组(LPS 10μg/ml+等体积正常组血清)、复肾颗粒小剂量组(LPS 10μg/ml+复肾颗粒100μg/ml)、复肾颗粒中剂量组(LPS 10μg/ml+复肾颗粒500μg/ml)、复肾颗粒大剂量组(LPS 10μg/ml+复肾颗粒1 mg/ml)。培养6、12和24 h后,用MTT法检测细胞增殖,ELISA法检测细胞上清中IL-6、TNF-α的含量,RT-PCR法检测α-SMA mRNA和TRAF6 mRNA的含量,Western bolt法检测α-SMA和TRAF6蛋白的表达。结果:LPS诱导组较对照组细胞的增殖水平、胞质中IL-6和TNF-α的含量及α-SMA和TRAF6的表达水平均增加,而不同剂量复肾颗粒干预后细胞增殖水平、IL-6和TNF-α的含量以及α-SMA和TRAF6的表达水平均减低,呈现一定的浓度依赖性,结果差异具有统计学意义(P0.05,P0.01)。结论:复肾颗粒可抑制LPS诱导的HK-2细胞增殖水平和炎性因子的释放,发挥抑制肾小管上皮细胞-肌成纤维细胞转变的纤维化过程,其机制可能与抑制TRAF6蛋白的表达有关。     

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.     

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.     

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.     

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.     

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.     

Systemic analgesia adapted to the children's condition

A concept of balanced analgesia using nonsteroidal anti-inflammatory drugs (NSAIDs), paracetamol (acetaminophen), opioids, and corticosteroids can also be used in patients with pre-existing illnesses. NSAIDs are the most effective treatment for acute pain of moderate intensity in children; however, these drugs should be avoided in patients at increased risk for serious side effects, e.g. patients with renal impairment, bleeding tendency, or extreme prematurity. NSAIDs can be given with minimal risks to the younger child with mild to moderate asthma, and, in these patients, the use of steroids can be encouraged; in addition to their antiemetic and analgesic action, a beneficial effect on asthma symptoms can be expected. In the non-intubated child with cerebral trauma, exaggerated sedation caused by opioids and increased bleeding tendency caused by NSAIDs must be avoided. In neonates and small infants, the oral administration of sucrose or glucose is helpful to minimize pain reaction during short uncomfortable interventions.