内质网应激分子伴侣GRP78在大鼠缺血再灌注损伤肝脏中的表达

目的:观察内质网应激相关分子葡萄糖调节蛋白78(GRP78)在大鼠缺血再灌注损伤肝脏组织中的表达水平.方法:将24只健康雄性SD大鼠随机均分为假手术组,单纯肝缺血组(肝缺血30 min+再灌注0h),再灌注6h组(肝缺血30 min+再灌注6h)和再灌注12h组(肝缺血30 min+再灌注12h).分别检测各组血清丙氨酸转氨酶(ALT)和门冬氨酸转氨酶(AST)水平;肝组织病理学、凋亡情况及GRP78 mRNA表达水平.结果:与对照组比较,各实验组大鼠肝缺血后出现明显的肝组织损伤,且随着再灌注时间的延长损伤加重,表现为血清ALT和AST水平升高,明显的肝组织病理学改变,肝细胞凋亡率增加,各组间计量指标的差异均有统计学意义(均P＜0.05).大鼠肝组织GRP78 mRNA变化趋势与上述指标一致,缺血后表达明显上调,且随着再灌注时间延长而逐渐升高,各组间差异均有统计学意义(均P＜0.05).结论:缺血再灌注损伤肝脏组织中GRP78表达上调,但其具体作用还有待于探明.     

乳化异氟醚对大鼠肺缺血-再灌注内质网应激的影响

目的探索乳化异氟醚预处理对大鼠肺缺血-再灌注损伤诱导内质网应激的影响。方法雄性SD大鼠32只随机分成四组:假手术组(S组)、缺血-再灌注组(IR组)、乳化异氟醚预处理(EI组)、脂肪乳组(IL组)。S组腹腔注射生理盐水10.5ml/kg,24h后仅开胸游离左肺门,不进行阻断左肺门;IR组、EI组和IL组分别腹腔注射生理盐水、8%乳化异氟醚10.5 ml/kg、30%脂肪乳10.5ml/kg,24h后通过阻断左肺门1h后再灌注2h建立大鼠原位肺缺血-再灌注损伤模型。于再灌注2h即刻经左心室采集血样检测PaO2、PaCO2值;取左肺组织测湿重/干重比(W/D),通过HE染色评估肺组织病理损伤程度;通过RT-PCR和Western blot检测肺组织中GRP78和CHOP的表达水平。结果与S组比较,IR组、EI组和IL组PaCO2、肺组织GRP78、CHOP mRNA和CHOP蛋白表达明显升高,PaO2明显降低(P0.05),GRP78蛋白表达水平差异无统计学意义;与IR组比较,EI组、IL组PaCO2、肺组织GRP78mRNA、CHOP mRNA和CHOP蛋白表达明显降低、PaO2明显升高(P0.05),GRP78蛋白表达水平差异无统计学意义。与IL组比较,EI组PaCO2、肺组织W/D、GRP78、CHOP mRNA和CHOP蛋白表达明显降低、PaO2明显升高(P0.05),GRP78蛋白表达水平差异无统计学意义。病理显示EI组和IL组肺损伤轻于IR组,EI组肺损伤轻于IL组。结论乳化异氟醚和脂肪乳预处理均可减轻大鼠术后肺缺血-再灌注损伤引起的过度内质网应激,并且乳化异氟醚的保护效果更显著。     

阿托伐他汀调控PERK/eIF2α/CHOP通路减轻造影剂诱导的大鼠肾小管上皮细胞凋亡

目的研究造影剂肾病大鼠肾脏中葡萄糖调节蛋白78(GRP78)、内质网调节激酶(PERK)、真核起始因子2α(eIF2α)及C/EBP同源蛋白质(CHOP)的表达情况,探讨内质网应激在造影剂肾病发病中的作用及阿托伐他汀的干预作用。 方法60只大鼠随机分为4组：对照组、模型组和高、低剂量阿托伐他汀组(80 mg,40 mg),每组15只。分别于注射造影剂后24、48、72 h留取血清;检测各组大鼠的血清尿素氮(BUN)、血清肌酐(Scr);TUNEL法及Western印迹法测casepase-3的表达检测肾小管上皮细胞凋亡;免疫组化和Western印迹法检测各组大鼠肾组织GRP78、p-eIF2α、p-PERK及CHOP的表达。 结果与对照组相比,模型组大鼠BUN、Scr显著升高,细胞凋亡严重,GRP78、p-eIF2α、p-PERK及CHOP的表达均显著升高(P< 0.05);与模型组相比,高、低剂量阿托伐他汀组,BUN、Scr显著下降,凋亡指数降低,GRP78、p-eIF2α、p-PERK及CHOP的表达显著下调,但仍高于对照组,差异均达到统计学意义(P<0.05);高、低剂量阿托伐他汀组之间上述各指标差异均不显著。 结论PERK/eIF2α/CHOP通路介导的内质网应激可能参与大鼠造影剂肾病的发生发展;阿托伐他汀在造影剂诱导的肾脏损伤中发挥保护作用,这可能与其调节PERK/eIF2α/CHOP通路,从而减轻内质网应激有关。     

祛痰通络汤对糖尿病大鼠肾组织内质网应激相关分子GRP78和CHOP表达的影响

目的:观察祛痰通络汤对糖尿病大鼠肾组织中内质网应激相关分子GRP78和CHOP表达的影响。方法:高糖高脂饲料联合腹腔注射STZ制备糖尿病模型,随机分为4组,分别为正常对照组、模型组、祛痰通络汤组、四苯基丁酸组,治疗8周。观察各组24 h尿蛋白定量、肾脏病理学变化;免疫组化和western-blot检测肾组织内质网应激相关蛋白GRP78,CHOP的表达。结果:祛痰通络汤降低尿蛋白,减轻病理改变;模型组肾组织的GRP78、CHOP表达明显升高(P0.05),祛痰通络汤组GRP78、CHOP表达明显低于模型组(P0.05)。结论:糖尿病大鼠肾脏中GRP78、CHOP表达明显增强,祛痰通络汤降低内质网应激,可能是其肾脏保护作用的重要机制。     

黄芪甲苷对大鼠肝脏缺血再灌注损伤和Caspase途径的影响

目的探讨黄芪甲苷对大鼠肝脏缺血再灌注损伤（HIRI）的保护作用以及相关机制。 方法将75只纯系SD大鼠随机分为Sham组（假手术组）、HIRI组（缺血再灌注组）以及黄芪甲苷低剂量组、中剂量组、高剂量组,建立大鼠HIRI模型,于再灌注4、8、16 h后取下腔静脉血及肝左外叶组织。全自动生化分析仪检测血清谷丙转氨酶（ALT）、谷草转氨酶（AST）水平;光学显微镜下观察肝细胞显微结构变化;Western Blotting及免疫组化染色分析肝组织中Caspase-3、8、9的表达;流式细胞仪检测肝细胞凋亡率。 结果HIRI组的ALT和AST水平升高,而黄芪甲苷组明显降低,且肝细胞损伤明显减轻。高剂量组Caspase-3、8、9蛋白的表达水平以及细胞凋亡率明显低于HIRI组。 结论黄芪甲苷预处理可减轻大鼠HIRI,其作用机制可能与其抑制Caspase-3、8、9的表达,从而抑制细胞凋亡有关。     

硫化氢抑制自噬减轻肝硬化大鼠肝脏缺血再灌注损伤

目的:探讨硫化氢(H_2S)预处理对肝硬化大鼠肝脏缺血再灌注损伤(HIRI)的影响及机制。方法:将32只采用胆总管结扎法制作的肝硬化模型大鼠随机均分为4组,分别行假手术(假手术组)、30 min肝门阻断及4 h再灌注诱导HIRI模型(HIRI组)、硫氢化钠(Na HS,外源性H_2S供体)预处理+HIRI模型诱导(Na HS组)、Na HS+雷帕霉素(RPM,m TOR抑制剂)预处理+HIRI模型诱导(RPM组),随后检测血清谷草转氨酶(AST)、谷丙转氨酶(ALT)浓度,分别用光镜与电镜观察肝组织病理学变化与自噬水平,Western blot检测肝组织LC3-II(自噬特异性标记)以及m TOR、磷酸化m TOR(p-m TOR)蛋白表达。结果:除假手术组外,其余各组肝组织在肝硬化表现的基础上均出现明显的炎症反应、细胞肿胀与局灶性坏死等损伤改变,但Na HS组的损伤程度明显轻于HIRI组与RPM组。与假手术组比较,其他各组血清AST、ALT水平均明显升高、肝细胞内自噬体数量明显增多、肝组织LC3-II蛋白表达明显升高,而p-m TOR蛋白表达(p-m TOR/m TOR比值)明显降低(均P0.05),但Na HS组转氨酶升高幅度、细胞内噬体数量、肝组织LC3-II蛋白升高及p-m TOR蛋白降低程度均明显低于HIRI组(均P0.05),而RPM组与HIRI组间各项指标差异均无统计学意义(均P0.05)。结论:H_2S预处理能减轻肝硬化大鼠HIRI,其机制可能与通过活化m TOR途径抑制自噬有关。     

褪黑素对大鼠移植肝组织GRP-78及CHOP表达的影响

目的通过检测褪黑素(MEL)对肝移植大鼠肝脏内质网应激(ERS)通路相关分子葡萄糖调节蛋白-78(GRP-78)及CCAAT增强子结合蛋白同源蛋白(CHOP)表达的影响,探讨MEL对移植肝的作用。方法采用"磁环法"制作大鼠原位肝移植模型,雄性SD大鼠随机分为3组:假手术组(Sham组)、原位肝移植组(OLT组)、原位肝移植+褪黑素处理组(OLT+MEL组),每组各8只。术后24 h,获取血清样本及肝脏标本。检测血清丙氨酸转移酶(ALT)及天冬氨酸转移酶(AST)水平,苏木素-伊红(HE)染色观察各组肝组织病理学改变,采用聚合酶链反应和蛋白免疫印迹试验检测GRP-78及CHOP的信使核糖核酸(mRNA)和蛋白表达水平。结果与Sham组比较,OLT组血清ALT、AST显著升高(均为P0.01),肝组织损伤严重,GRP-78及CHOP在mRNA和蛋白水平表达明显增加(均为P0.01)。与OLT组比较,OLT+MEL组大鼠ALT、AST水平明显降低(均为P0.05),肝组织损伤减轻,GRP-78及CHOP mRNA和蛋白表达水平明显降低(均为P0.05)。结论褪黑素能降低移植肝ERS相关分子GRP-78及CHOP在mRNA和蛋白水平的表达,这可能是它减轻移植后肝脏损伤的机制之一。     

外源性左旋肉碱对过度内质网应激介导的严重烫伤大鼠肝细胞焦亡的影响及其分子机制

目的探讨外源性左旋肉碱对过度内质网应激介导的严重烫伤大鼠肝细胞焦亡的影响及其分子机制。方法采用实验研究方法。将15只6～8周龄雌性SD大鼠按随机数字表法(分组方法下同)分为假伤组、单纯烫伤组、烫伤+肉碱组, 每组5只, 单纯烫伤组和烫伤+肉碱组大鼠背部制作30%体表总面积的Ⅲ度烫伤, 其中烫伤+肉碱组大鼠另外给予腹腔注射左旋肉碱。伤后72 h, 采用全自动生化仪检测肝损伤生物化学指标天冬氨酸转氨酶(AST)和丙氨酸转氨酶(ALT)水平, 样本数为5。伤后72 h, 采用苏木精-伊红染色观察肝组织损伤情况。伤后72 h, 采用实时荧光定量反转录PCR(RT-qPCR)法检测肝组织中细胞焦亡相关标志物核苷酸结合寡聚化结构域蛋白样受体热蛋白结构域相关蛋白3(NLRP3)、胱天蛋白酶1(caspase-1)、消皮素D和白细胞介素1β(IL-1β)以及内质网应激相关标志物葡萄糖调节蛋白78(GRP78)、CCAAT/增强子结合蛋白同源蛋白(CHOP)的mRNA水平;采用蛋白质印迹法检测肝组织中GRP78、CHOP、NLRP3、caspase-1、caspase-1/p20、消皮素D-N、剪切型I...     

落新妇苷对大鼠肝脏缺血再灌注损伤及自噬的影响

目的探讨落新妇苷对大鼠肝脏缺血再灌注损伤（HIRI）的保护作用及自噬的影响。 方法将54只SD大鼠随机分为假手术组（Sham组）、缺血再灌注组（HIRI组）以及落新妇苷组（40 mg·kg^-1·d^-1,连续7 d）,每组18只。建立大鼠HIRI模型,于再灌注4、8、16 h后取下腔静脉血及肝左外叶组织。全自动生化分析仪检测血清丙氨酸氨基转移酶（ALT）、天冬氨酸氨基转移酶（AST）水平;光学显微镜下观察肝细胞显微结构变化;Western blotting分析肝组织中自噬相关蛋白LC3、Beclin-1的表达;电镜下观察肝脏组织内自噬小体数量情况。 结果同检测时间点比较,Sham组和落新妇苷组的血清ALT和AST水平均低于HIRI组（P<0.05）,且肝细胞肿胀、炎性细胞浸润、汇管区结构损伤明显较轻。落新妇苷组LC3-Ⅱ/ LC3-Ⅰ灰度值比值及Beclin-1蛋白灰度值在术后4、8、16 h明显低于HIRI组（P<0.05）。落新妇苷组肝组织的自噬小体数量较HIRI组有所减少（3.68±0.42 vs 7.12±0.60,t=36.382,P<0.01）。 结论落新妇苷预处理可减轻大鼠HIRI,其作用机制可能与其抑制自噬有关。     

鸡尾酒神经保护剂降低急性脊髓损伤大鼠的内质网应激水平并促进运动功能恢复

[目的]观察鸡尾酒神经保护剂N6对SD大鼠急性脊髓损伤后脊髓组织内质网应激相关蛋白GRP78和CHOP表达量的影响以及运动功能恢复情况,探讨鸡尾酒制剂对损伤脊髓的保护作用机制。[方法]60只雌性SD大鼠被随机分为5组(n=12),假手术组(Sham组)、单纯脊髓损伤组(SCI组)、甲强龙30 mg/kg腹腔给药组(MP-a组)、甲强龙20μl蛛网膜下腔给药组(MP-b)和鸡尾酒神经保护剂20μl蛛网膜下腔给药组(Cocktail组)。采用NYU打击器建立大鼠急性脊髓损伤模型,给药组造模成功后10 min即给予相应药物治疗。各组大鼠于治疗后72 h,提取损伤段脊髓蛋白,用Western-blot方法检测GRP78和CHOP相对表达量,灌注后取损伤段脊髓做CHOP免疫荧光染色。各组剩余大鼠每7d进行后肢运动功能BBB评分,28 d时取损伤段脊髓,Luxol Fast Blue染色后观察髓鞘再生情况。[结果]与SCI组、MP-a和MP-b组相比,Cocktail组GRP78表达水平明显升高(P0.05)、CHOP表达水平明显降低(P0.05),BBB评分在第14、21、28 d有明显升高(P0.05),髓鞘存留面积较大。[结论]采用鸡尾酒神经保护剂N6蛛网膜下腔给药的方法治疗大鼠急性损伤,可有效降低脊髓组织CHOP表达量,抑制内质网应激水平,促进髓鞘再生和运动功能恢复。     

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.