不同剂量重组人促红细胞生成素对大鼠肾脏缺血再灌注损伤保护作用的研究

目的探讨不同剂量重组人促红细胞生成素(recombinant human erythropoietin,rhEPO)对大鼠肾脏缺血再灌注损伤(renal ischemia reperfusion injury,RIRI)的保护作用及其机制。方法将40只健康的雄性大鼠随机分为5组:假手术组(S组),缺血再灌注模型组(IR组),rhEPO大剂量治疗组(H组),rhEPO中剂量治疗组(M组),rhEPO小剂量治疗组(L组)。IR组、H组、M组、L组分别通过夹闭双侧肾动、静脉45 min,制作大鼠RIRI模型,H组、M组、L组于造模成功后分别按照5 000 IU/kg、3 000 IU/kg、1 000 IU/kg标准给予腹腔注射rhEPO。比色法测定血清肌酐(SCr)和尿素氮(BUN),免疫组化分析法测定血红素加氧酶-1(heme oxygenase-1,HO-1)、白细胞介素6(interleukin-6,IL-6),HE染色分析肾组织形态学变化。结果与S组比较,IR组大鼠SCr及BUN水平于缺血再灌注1 h即有显著上升(P0.05),并且随着再灌注时间的延长逐渐升高。在各个再灌注时间点(1、6、12、24 h)上,H组、M组的SCr、BUN较IR组均有下降趋势,但以H组下降幅度最明显。L组与IR组相比较,肾功能无明显改善。至再灌注后24 h,BUN与SCr均未达峰值。IR组肾组织中IL-6、HO-1的表达明显高于S组。H组、M组中IL-6的水平均显著降低,HO-1水平升高,且与rhEPO的剂量相关,而L组与IR组相比无明显差异。IR主要累及肾小管上皮细胞。与IR组比较,S组可见正常大鼠肾小球及肾小管的组织形态结构,在各个时间点均未出现明显的组织坏死。结论rhEPO对RIRI有保护作用,且剂量越大,对缺血再灌注损伤的保护作用越明显。推测其保护机制可能与rhEPO抑制肾小管上皮细胞凋亡而减轻RIRI相关。     

姜黄素预处理对大鼠缺血再灌注肾小管上皮细胞凋亡的影响

目的：建立大鼠。肾脏缺血再灌注损伤（IRI）模型,观察姜黄素预处理对大鼠肾脏缺血再灌注肾小管上皮细胞凋亡的影响。方法：36只SD雄性大鼠随机分为3组,分别为假手术（Sham）组、肾脏缺血再灌注模型（IR）组、姜黄素预处理（CUR）组,每组12只。CUR组在缺血前2h给予姜黄素100mg／kg剂量溶于0．1％二甲基亚砜1ml中,注入腹腔。24小时后沿原切口进入,切除左。肾。肾组织用4％多聚甲醛固定24h,常规石蜡包埋切片。采用TUNEL法检测各组缺血肾小管上皮细胞凋亡。结果：与Sham组相比,IR组肾小管上皮细胞凋亡明显增加。与IR组比较,CUR组肾小管上皮细胞凋亡减少（P＜0．05）。结论：姜黄素预处理可减轻肾脏IRI的肾小管上皮细胞凋亡。     

大鼠肾缺血再灌注后炎症反应和间质血管病变研究

目的：探讨在缺血再灌注（ischemia/reperfusion,I/R）模拟急性肾损伤的大鼠模型中间质血管损伤状况及其病变机制。方法：按随机分组将15只SD大鼠分为假手术组（sham）、肾缺血再灌注损伤（I/R）6 h组、24 h组,每组5只,测定血尿素氮水平,并观察肾脏病理改变;免疫组织化学法观察巨噬细胞浸润、促血管生成因子-血管内皮生长因子（VEGF）的表达,免疫荧光法检测肾小管间质血管的分布,原位缺口末端标记法（TUNEL）检测肾小管上皮细胞凋亡。结果：I/R 6 h、24 h组与sham组相比,BUN明显升高（P〈0.05）,巨噬细胞浸润明显（P〈0.05）,VEGF表达量下降,间质血管密度下降（P〈0.05）,上皮细胞凋亡增多（P〈0.05）。结论：I/R损伤后炎症细反应所致间质血管密度降低是肾小管上皮细胞损伤的重要机制。     

热休克蛋白70对肾脏缺血预处理保护作用的研究

目的 :研究缺血预处理对肾脏缺血再灌注损伤的保护作用 ,观察热休克蛋白 70 (HSP70 )的表达变化并探讨其作用机制。方法 :建立大鼠肾脏缺血再灌注损伤模型并进行缺血预处理 ,实验分组 :假手术组 (S组 )、缺血再灌注组 (IR组 )和缺血预处理组 (PC组 )。各组再灌注后检测血清肌酐 (Scr)、肾组织丙二醛 (MDA)含量 ,肾组织石蜡切片苏木精伊红染色以及免疫组化染色。结果 :PC组Scr值、肾小管病理评分、肾组织中MDA含量明显低于IR组 (P <0 .0 5 ) ,PC组与S组比较差异无显著性意义 (P >0 .0 5 ) ;HSP70免疫组化染色 :S组未见明显的阳性反应产物 ,PC组和IR组肾小管上皮细胞胞质可见棕黄色阳性反应产物。计算机图像分析显示PC组灰度值显著高于IR组 (P <0 .0 1)。结论 :缺血预处理对肾脏缺血再灌注损伤有明显保护作用 ,其作用机制可能与HSP70本身的细胞保护作用及HSP70的细胞内抗氧化作用有关     

乌司他丁对大鼠肾缺血/再灌注损伤的保护作用

目的探讨乌司他丁对大鼠肾缺血/再灌注(I/R)损伤的作用及其机制.方法雄性SD大鼠75只,随机分为三组假手术对照组(C组)、肾I/R组(I组)、乌司他丁组(U组),每组25只.I组和U组大鼠夹闭双侧肾蒂45min后重新开放肾脏血供,制作肾脏I/R模型,C组不夹闭双侧肾蒂.U组缺血前30min及再灌注开始时静脉注射乌司他丁1.25万单位,I组分别静脉注射生理盐水1ml.各组在再灌注后0、2、6、12、24h时取标本,测定血尿素氮(BUN)和血肌酐(Cr)浓度,并制备肾脏病理切片,采用免疫组化方法测定热休克蛋白70(HSP70)和bcl-2蛋白的表达.结果与I组比较,C组在再灌注后各时点血清BUN和Cr浓度均降低(P＜0.05),U组在再灌注后12、24h时血清BUN和Cr浓度也降低(P＜0.05).C组肾脏未发现明显的形态学改变;I组近曲小管上皮细胞空泡变性和坏死,肾小管腔扩张,内可见管型和坏死脱落细胞,可见管周血管明显扩张淤血;U组近曲小管上皮细胞肿胀、颗粒变性,罕见管型,管周稍有淤血.与I组比较,C组在再灌注后0、6、12、24h时Paller评分降低(P＜0.05),U组在再灌注后0、6、24h时Paller评分也降低(P＜0.05),C组再灌注后12、24h时HSP70表达降低(P＜0.05),U组在再灌注后6、24h时bcl-2蛋白表达增强(P＜0.05).结论乌司他丁对肾脏I/R损伤有保护作用,其机理可能与上调肾脏bcl-2蛋白表达有关.     

通过短时间预缺血改变肾小管上皮细胞命运诱导肾脏缺血耐受

目的 探讨短时间缺血预处理在诱导肾脏缺血耐受中的作用,及其对肾小管上皮细胞坏死、凋亡、增殖等的影响。 方法 雄性SD大鼠随机分为3组：假手术组（Sham）,只分离两侧肾蒂,不进行夹闭;单纯缺血再灌注组（I/R）,第0天假手术,第4天用无损伤动脉夹夹闭两侧肾蒂40 min,然后恢复灌注;缺血预适应组（IPC）,第0天预缺血20 min,第4天再次缺血40 min。PAS染色观察肾组织形态学,透射电镜观察小管上皮细胞超微结构,原位末端标记法（TUNEL）检测细胞凋亡情况,免疫组织化学法观察肾小管上皮细胞增殖核抗原（PCNA）的表达。 结果　与单纯缺血再灌注组相比,缺血预适应组肾脏功能和病理性损伤显著减轻（P < 0.01）;大鼠死亡率从33%降低为0 ;肾小管上皮细胞凋亡和坏死显著减少（P < 0.05）,细胞增殖（PCNA阳性）显著增多（P < 0.01）。 结论 短时间缺血预处理能诱导肾脏耐受长时间缺血,减少小管上皮细胞死亡和促进其及时增殖修复可能是预缺血发挥肾脏保护作用的机制之一。     

缺血预处理对大鼠缺血再灌注心肌HIF-1α和HO-1的影响

目的 探讨缺血预处理对大鼠缺血再灌注心肌低氧诱导因子1α(HIF-1α)和血红素加氧酶1(HO-1)的影响.方法 健康雄性SD大鼠48只,体重220～280 g,随机分为4组(n=12):假手术组(S组)、缺血再灌注组(IR组)、缺血预处理+缺血再灌注组(IP组)和缺血预处理+缺血再灌注+HO-1抑制剂组(HI组).采用结扎左冠状动脉前降支30 min再灌注120 min的方法建立心肌缺血再灌注模型.S组仅在冠状动脉下穿线;IP组于缺血前采用结扎/放松左冠状动脉前降支各5 min,重复3次的方法行缺血预处理;HI组于缺血预处理前1 d腹腔注射锌原卟啉Ⅸ 10 ms/ks,其余同IP组.于再灌注结束时测定心肌HIF-1α、HO-1的mRNA和蛋白表达、HO-1活性、SOD活性及MDA含量,计算心肌梗死面积,取动脉血样测定血清TNF-α和IL-6的浓度.结果 与S组比较,IR组、IP组和HI组心肌SOD活性降低,MDA含量升高,血清TNF-α和IL-6的浓度升高(P＜0.01);与IR组比较,IP组心肌SOD活性升高,MDA含量降低,血清TNF-α和IL-6浓度降低,心肌HIF-1α和HO-1的mRNA和蛋白表达上调,HO-1活性升高,心肌梗死面积减小(P＜0.01);与IP组比较,HI组心肌SOD活性降低,MDA含量升高,血清TNF-α和IL6浓度升高,心肌HO-1的mRNA和蛋白表达下调,HO-1活性降低,心肌梗死面积增加(P＜0.05或0.01),心肌HIF-1α的mBNA和蛋白表达差异无统计学意义(P＞0.05).结论 缺血预处理减轻大鼠心肌缺血再灌注损伤的机制与HIF-1α诱导HO-1活性增强有关.     

细胞穿透肽PEP-1介导血红素加氧酶-1对大鼠离体心脏缺血再灌注损伤的影响

目的 探讨细胞穿透肽PEP-1介导血红素加氧酶-1(HO-1)对大鼠离体心脏缺血再灌注损伤的影响.方法 雄性SD大鼠,体重220～280g,制备Langendorff离体心脏灌注模型,选取模型制备成功的离体心脏18个,随机分为3组(n=6):假手术组(S组)、缺血再灌注组(IR组)和PEP-1/HO-1处理+缺血再灌注组(HO-1组).IR组K-H液平衡灌注30 min后,采用停灌40 min再灌注50 min的方法制备缺血再灌注模型.HO-1组在停灌前用含50 μmol/L融合蛋白PEP-1/HO-1的K-H液平衡灌注15 min,S组采用K-H液持续灌注120 min.再灌注50 min时,收集冠脉流出液,测定肌酸激酶(CK)和乳酸脱氢酶(LDH)的活性;取心肌组织,采用Western blot法测定HO-1蛋白表达水平,采用硫代巴比妥酸比色法测定MDA含量,黄嘌呤氧化酶法测定SOD活性.结果 HO-1组心肌组织HO-1蛋白表达水平较IR组升高(P＜0.01).与S组比较,IR组和HO-1组冠脉流出液CK和LDH活性及心肌组织MDA含量升高,心肌组织SOD活性降低(P＜0.01);与IR组比较,HO-1组冠脉流出液CK和LDH活性及心肌组织MDA含量降低,心肌组织SOD活性升高(P＜0.01).结论细胞穿透肽PEP-1可将HO-1蛋白成功导入心肌组织,并减轻大鼠心肌缺血再灌注损伤.     

中性粒细胞明胶酶相关脂质运载蛋白对大鼠肾脏缺血再灌注损伤肾小管上皮细胞的保护作用

目的 探讨中性粒细胞明胶酶相关脂质运载蛋白(NGAL)对大鼠缺血再灌注损伤肾脏肾小管上皮细胞凋亡的保护作用及机制.方法 建立大鼠肾脏缺血再灌注模型,雄性SD大鼠随机分为对照组、缺血再灌注模型组、NGAL组 ;HE染色观察3组大鼠肾组织病理变化 ;TUNEL法检测肾小管上皮细胞凋亡 ;实时定量PCR、Western印迹法检测凋亡蛋白fas、bcl-2的表达变化.结果 与缺血再灌注模型组比较,NGAL组肾小管上皮细胞凋亡数量显著减少[(8.6±3.4)/HP比(20.8±3.7)/HP,P＜0.05] ;NGAL组肾组织fas mRNA(2.34±0.51比6.84±2.34,P＜0.05)、fas蛋白(0.65±0.05比0.95±0.08,P＜0.05)表达显著下调,bcl-2蛋白(0.33±0.05比0.24±0.03,P＜0.05)表达显著上调,但bcl-2 mRNA表达无明显改变.结论 NGAL对大鼠缺血再灌注损伤肾小管上皮细胞有保护作用,其作用可能与减少细胞凋亡、改变凋亡蛋白的表达有关.     

细胞穿透肽PEP-1介导血红素加氧酶-1对大鼠肠缺血再灌注损伤的影响

目的 评价细胞穿透肽PEP-1介导血红素加氧酶-1(HO-1)对大鼠肠缺血再灌注损伤的影响.方法 雄性SD大鼠18只,周龄7～9周,体重210～260 g,采用随机数字表法,将大鼠随机分为3组(n=6):假手术组(S组)、肠缺血再灌注组(IR组)和融合蛋白PEP-1/HO-1+肠缺血再灌注组(HO组).采用夹闭肠系膜上动脉45 min,恢复灌注120 min的方法制备大鼠肠缺血再灌注损伤模型.HO组夹闭肠系膜上动脉前30 min,左侧髂静脉注射融合蛋白PEP-1/HO-1 0.5 mg,S组不夹闭肠系膜上动脉,余操作同IR组.于再灌注120 min时处死大鼠取小肠组织,称重后计算肠湿/干重比,测定丙二醛(MDA)含量、超氧化物歧化酶(SOD)活性和HO-1活性,免疫组化法检测肠组织HO-1蛋白的表达,光镜下观察肠组织结构并进行损伤评分.结果 与S组比较,IR组和HO组肠湿/干重比和MDA含量升高,SOD活性降低,HO-1活性和蛋白表达水平升高,损伤评分升高(P＜0.05);与IR组比较,HO组肠湿/干重比、MDA含量降低,SOD活性升高,HO-1活性和蛋白表达水平升高,损伤评分降低(P＜0.05).HO组大鼠肠组织病理学损伤较IR组减轻.结论 细胞穿透肽PEP-1可将HO-1成功导人大鼠肠组织中的细胞并减轻肠缺血再灌注损伤.

Abstract：

Objective To investigate the effects of heme oxygenase-1 (HO-1) mediated by cell penetrating peptide PEP-1 on intestinal ischemia/reperfusion (I/R) injuiy in tats. Methods Eighteen male SD rats aged 7-9 weeks weighing 210-260 g were randomly divided into 3 groups (re = 6 each): sham operation group (group S) , I/R group and PEP-1/HO-1 + I/R group (group HO) . To establish a model of intestinal I/R injury, intestines were exteriorized and the superior mesenteric artery was exposed and occluded for 45 min ischemia, and then the clamp was removed for 120 min reperfusion. The PEP-1/HO-1 fusion protein 0.5 mg was injected via the left iliac vein 30 min prior to ischemia in group HO. The superior mesenteric artery was exposed but not occluded in group S. At the end of reperfusion, the rats were sacrificed and intestinal tissues obtained to determine the intestinal wet/ dry ratio, malondialdehyde (MDA) level, activities of superoxide dismutase (SOD) and HO-1, and HO-1 protein expression. The histological changes in the intestinal mucosa were examined and the injuiy was scored. Results Compared with group S, the intestinal wet/dry ratio, MDA level, HO-1 activity, HO-1 protein expression and injury score were significantly increased, while the SOD activity was significantly decreased in groups I/R and HO ( P ＜ 0.05) . Compared with group I/R, the intestinal wet/dry ratio, MDA level and injury score were significantly decreased, while the SOD activity, HO-1 activity and HO-1 protein expression increased in group HO ( P ＜ 0.05) . The pathologic changes were significantly attenuated in group HO compared with group I/R.Conclusion HO-1 protein can be successfully delivered into intestinal tissues by PEP-1 and has protective effects against intestinal I/R injury.     

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.