粉防己碱和环孢素A在大鼠心脏移植中的协同作用

目的 研究粉防己碱(Tetrandrine,Tet)和低剂量环孢素A(CsA)联合使用对同种异基因大鼠移植心脏存活时间的影响.方法 分别以近交系雄性Lewis(RT11)大鼠和BN(RT1n)大鼠为供、受者,将接受心脏移植后的BN大鼠随机分为5组,术后开始连续每天腹腔注射给药.A组:给予生理盐水1 ml/d;B组:给予CsA 3.2 mg·kg-1·d-1;C组:给予Tet 40 mg·kg-1·d-1;D组:给予Tet 40 mg·kg-1·d-1和CsA 3.2 mg·kg-1·d-1;E组:给予CsA 6 mg·kg-1·d-1.观察移植心存活时间并进行病理检查,测定受者外周血CD3+CD25+ T淋巴细胞数量、体外单向混合淋巴细胞反应以及受者血清白细胞介素2(IL-2)浓度等.结果 A、B、C、D、E组大鼠的移植心平均存活分别为(7.2±0.45)d、(10.8±1.48)d、(9±1.0)d、(15.6±3.05)d和(15.2±2.28)d,D、E组移植心存活时间比A组显著延长(P＜0.05),术后6 d D组外周血CD3+CD25+ T淋巴细胞数量、单向混合淋巴细胞反应刺激指数、血清 IL-2浓度较A组显著降低(P＜0.05),D组移植心排斥反应程度最轻.结论 Tet和低剂量CsA联合应用能显著延长同种异基因大鼠移植心的存活时间,其机理可能与抑制反应性T淋巴细胞活化以及抑制外周血清IL-2产生等有关.     

AG490延长移植心存活时间的探讨

目的 研究AG490在大鼠心脏移植中免疫抑制及延长移植心存活时间的作用,探讨AG490的作用机制.方法 供者为SD大鼠,受者为Wistar大鼠,建立大鼠心脏移植模型.将受者分为4组.对照组(14只):术后1～7 d经尾静脉注射生理盐水0.2 ml·kg-1·d-1;AG490组(14只):术后1～7 d经尾静脉注射AG490 20 mg·kg-1·d-1;CsA组(10只):术后1～7 d经尾静脉注射CsA20 mg·kg-1·d-1;AG490+CsA组(10只):术后1～7 d经尾静脉注射AG490和CsA各20mg·kg-1·d-1.术后各组分别取10只受者,观察移植心存活时间,并在术后1、4和7 d时,检测受者外周血中白细胞介素(IL)-2和IL-6的水平.术后第7天,处死对照组和AG490组受者(各4只)后,分别取移植心组织进行病理学检测.结果 AG490组受者术后移植心存活时间为(26.6±3.81)d,CsA组为(28.4±4.25)d,AG490+CsA组为(31.8±4.39)d,均较对照组的(8.4±0.84)d显著延长(P＜0.05).与对照组相比,AG490组术后外周血IL-2水平显著降低(P＜0.05),IL-6水平虽有所降低,但差异无统计学意义(P＞0.05),而AG490+CsA组IL-2和IL-6水平下降更为显著,与对照组相比,差异均有统计学意义(P＜0.05).AG490组移植心组织中淋巴细胞浸润程度较对照组明显减轻.结论 AG490具有免疫抑制作用,能延长移植物的存活时间,与CsA联合应用时效果更加明显.AG490的主要作用机制包括降低IL-2表达的水平,抑制移植心组织中淋巴细胞的浸润.     

输注供鼠骨髓间充质干细胞延长肾移植大鼠的存活时间

目的 探讨在同种大鼠肾移植中输注供者骨髓间充质干细胞(MSC)对急性排斥反应的影响以及延长受鼠存活时间的作用.方法 取Wistar大鼠骨髓,分离和培养其MSC.以Wistar 大鼠为供者,Lewis大鼠为受者,建立同种大鼠肾移植模型.根据受鼠处理方式的不同,分为低剂量MSC组、高剂量MSC组、CsA组及对照组,低剂量MSC组和高剂量MSC组于移植前后分别多次输注1×106个和t×107个供者MSC,CsA组于术后2d开始腹腔内注入CsA 0.5 mg·kg-1 ·d-1,以腹腔内注射PBS作为对照.移植后,比较各组受鼠的存活时间,观察各组移植肾功能及移植肾组织病理学改变.结果 低剂量MSC组、高剂量MSC组、CsA组及对照组受鼠的存活时间分别为(21.7±7.2)d、(31.2±14.3)d、(34.9±15.7)d及(9.0±2.3)d;低剂量MSC组、高剂量MSC组和CsA组存活时间均明显长于对照组(P＜0.01),而低剂量MSC组存活时间明显短于高剂量MSC组和CsA组(P＜0.05).术后第4天,高剂量MSC组和CsA组移植肾组织形态和结构基本正常;对照组移植肾组织则表现出典型的急性排斥反应,出现广泛间质性浸润,肾小管炎症和片状坏死、出血,肾小球炎症浸润严重;而与对照组相比,低剂量MSC组急性排斥反应的病理表现则要明显减轻.结论 同种肾移植大鼠输注供者MSC后,可以达到有效的免疫调节作用,并且可明显延长大鼠的存活时间,呈MSC剂量依赖性.     

雷帕霉素阶梯用药方案在异基因大鼠皮瓣移植模型中的疗效观察

目的探讨异基因大鼠皮瓣移植模型中雷帕霉素阶梯用药方案的疗效。方法建立近交系大鼠下腹部皮瓣移植模型。Ⅰ组(n=5)不予免疫抑制剂;Ⅱ组(n=5)给予雷帕霉素2mg·kg-1·d-1;Ⅲ组(n=5)给予雷帕霉素4mg·kg-1·d-1;Ⅳ组(n=8)术后第1～2周给予雷帕霉素4mg·kg-1·d-1,第3周改为2mg·kg-1·d-1,第4周后减量至1mg·kg-1·d-1。3组给药时间持续至术后60d或移植皮瓣死亡为止。大体观察各组移植皮瓣排斥反应发生的时间。分别于术后7、15、30d取移植皮瓣皮肤组织(每个时间点每组3只)行HE染色,观察病理学变化。结果Ⅲ组5例全部存活至术后60d,Ⅳ组7例存活至术后60d,而Ⅱ组移植皮瓣在术后60d前全部发生排斥反应,Ⅳ组与Ⅱ组比较移植皮瓣存活率差异有统计学意义(P0.05),与Ⅲ组比较差异无统计学意义(P0.05)。根据Banff07标准评分,术后7d时Ⅰ组为3级,其余各组为0级;术后15d时Ⅱ组为2级,Ⅲ、Ⅳ组为0级;术后30d时Ⅳ组中1例为4级,其余存活移植皮瓣为0级。结论本实验证实雷帕霉素阶梯用药与大剂量持续给药有相同的抑制排斥反应效果。     

激活型Akt1转染大鼠胰岛联合免疫抑制剂在异种胰岛移植中的应用

目的 探讨腺病毒载体介导激活性Akt1基因(Adv-CA-Akt1)转染大鼠胰岛对异种移植胰岛功能和存活的影响.方法 以BALB/C糖尿病小鼠为受体,分离纯化雄性Wistar大鼠胰岛,体外培养,Adv-CA-Akt1转染后异种胰岛移植.受体小鼠分3组,实验组:Adv-CA-Akt1转染的大鼠胰岛体外培养24 h,小鼠肾被膜下移植,并口服环孢素A(CsA)30 mg·kg-1·d-1;CsA组:未转染胰岛移植,同剂量环孢素口服;对照组:单纯胰岛移植.每只接受300胰岛当量(IEQs)移植.检测术后血糖,移植物存活时间及组织病理学.结果 实验组和CsA组术后2 d血糖即降至正常,胰岛功能存活时间分别为(21.0±3.65)d和(9.0±2.54)d,而对照组血糖短暂下降后再次升高,胰岛功能存活时间(4.2±2.6)d.实验组小鼠生存时间为(31.0±5.67)d比CsA组(17.0±3.35)d和对照组(10.0±1.52)d明显延长,三组比较差异有统计学意义(P<0.05);胰岛素免疫组化染色实验组.肾被膜下见较多有功能胰岛细胞团,而CsA组和对照组胰岛素染色阳性细胞数减少.结论 Adv-CA-Akt1转染大鼠胰岛联合应用免疫抑制剂,可提高胰岛功能,延长异种胰岛移植物存活时间.     

1O-羟基喜树碱和环孢素A诱导异基因大鼠心脏移植受者免疫耐受的实验研究

目的以中药制剂10-羟基喜树碱(HCPT)和环孢素A(CsA)诱导异基因大鼠心脏移植受者免疫耐受,并探讨免疫耐受的特异性和形成机制.方法以纯系SD大鼠为供者,纯系Wis-tar大鼠为受者行异体颈部心脏移植.将移植后50只受者大鼠随机分成5组,分别接受不同剂量HCPT、CsA或二者联合应用.A组接受安慰剂.B组接受HCPT 1.0mg·kg-1·d-1,腹腔注射.C组接受HCPT 2.0 mg·kg-1·d-1,腹腔注射.E组接受CsA10.0 mg·kg·d-1,导管灌胃.F组联合应用HCPT和CsA,方法剂量同B组和E组.心脏移植物长期存活受者术后60 d停用免疫抑制剂,120 d同时行供者来源(SD)大鼠和无关供者(SHR)大鼠皮肤移植.结果3只C组大鼠和5只F组大鼠心脏移植术后停用免疫抑制剂长期存活超过730 d.8块SD大鼠皮肤移植物长期存活超过610 d,而8块SHR大鼠皮肤均被排斥,平均存活时间(4.50±1.25)d.结论大剂量HCPT或小剂量HCPT与CsA联合应用可诱导异基因大鼠心脏移植受者免疫耐受,且形成的免疫耐受具有明确的抗原特异性.     

大黄素对大鼠肝移植后CD4~+CD25~+调节性T细胞的影响

目的研究大黄素对大鼠肝移植后CD4+CD25+调节性T细胞的比例以及对其免疫抑制功能的影响。方法双袖套法建立大鼠原位肝移植模型,以大黄素和环孢素A(CsA)分别在术后腹腔给药,并以给予PBS作为模型对照组,观察不同药物移植后大鼠存活时间的影响,以及对移植术后大鼠外周血中CD4+CD25+调节性T细胞(Tregulatory cells,Treg)亚群的变化以及免疫功能的影响。结果大黄素能显著延长大鼠原位肝移植的术后成活时间,大黄素组大鼠的平均存活时间(17.4±2.5)d与肝移植模型对照组(8.8±1.9)d相比差异具有统计学意义;大鼠肝移植后大黄素给药可显著上调受体大鼠外周血以及肝内CD4+CD25+Treg的比例,并显著增强CD4+CD25+Treg抑制效应性T细胞的增殖能力(P0.05)。结论大黄素能够延长大鼠原位肝移植的术后成活时间,并可能通过上调外周血以及肝内CD4+CD25+Treg的数量及免疫抑制功能来实现移植后免疫排斥反应的抑制。     

钙离子通道阻滞剂在预防他克莫司肾毒性中的作用

目的 观察他克莫司(FK506)肾毒性模型中钙离子代谢的变化情况,探讨钙离子通道阻滞剂地尔硫草(Dil)对FK506肾毒性的预防作用.方法 按公式将肾移植术后FK506、环孢素(CsA)和Dil的首剂治疗剂量换算成大鼠的治疗剂量.雄性SD大鼠24只随机分成对照组、CsA组(25 mg·kg-1·d-1)、FK506组(0.8 mg·kg-1·d-1)和FK506加Dil组(0.8 mg·kg-1·d-1及8 mg·kg-1·d-1),每组6只,用药4周后建立各组大鼠肾毒性模型.观察各组大鼠SCr、血电解质、肾组织的病理改变(HE染色)、电子显微镜F肾脏细胞内超微结构的改变.结果 CsA组和FK506组大鼠SCr值分别为(36.00±2.61)和(34.17±4.54)μmol/L,均高于FK506加Dil组和对照组[(28.50±2.07)和(29.17±3.43)μmol/L,P＜0.05].CsA组和FK506组大鼠血钙浓度分别为(2.00±0.04)和(2.05_4-0.04)mmol/L,均低于FK506加Dil组和对照组(P＜0.05).CsA组和FK506组均可观察到肾小管细胞轻微肿胀及空泡变性、线粒体肿胀及空泡化等病理改变.与FK506组和CsA组相比,FK506加Dil组上述各项指标的变化明显减轻或接近正常.结论 钙离子代谢紊乱可能介导了FK506引起的肾毒性,Dil可用于预防FK506的肾毒性.     

大黄素对大鼠肝移植后肝细胞凋亡的影响

目的：探讨大黄素对大鼠肝移植后肝细胞凋亡的影响。方法：建立LEW→BN大鼠肝移植动物模型,随机分为A组（排斥反应组）、B组（CsA组）、C组（大黄素组）、D组（CsA＋大黄素组）4组,每组6只。术后每天分别腹腔注射生理盐水0.5mL/d、环孢素A（CsA）10.0mg/（kg&#183;d）、大黄素50.0mg/（kg&#183;d）、大黄素50.0mg/（kg&#183;d）＋CsA10.0mg/（kg&#183;d）。连续用药8d,停药后处死动物取肝脏组织观察肝细胞凋亡指数（AI）和排斥活动指数（RAI）。结果：A、B、C、D组AI分别是35.83&#177;2.32、15.83&#177;1.33、16.50&#177;2.35、11.50&#177;1.05,RAI分别是7.67&#177;0.98、5.17&#177;0.40、5.83&#177;0.75、3.83&#177;0.75。B、C、D组的AI、RAI较A组均明显降低（P〈0.01）,而D组较B、C组也均有明显降低（P〈0.05）,B、C组间差别均无意义（P〉0.05）。结论：大黄素能有效减少大鼠移植肝术后肝细胞凋亡,抑制排斥反应。     

骨化三醇在抑制大鼠同种肢体移植排斥反应中的作用

目的 探讨应用骨化三醇(1,25-二羟维生素D;简称:VD5)在抑制肢体移植排斥反应中的作用.方法 以Wistar大鼠为供者,SD大鼠为受者,建立同种肢体移植模型.随机将受者分为4组,每组12只.(1)对照组:术后不用免疫抑制剂,仅以15 ml·kg-1·d-1.生理盐水灌服.(2)他克莫司(FK506)组:将FK506用生理盐水稀释为0.5 mg/ml,术后前2周的用量为1.0 mg·kg-1·d-1,术后第3周起,每周灌服2次.(3)VD3组:将骨化三醇用生理盐水稀释为0.125 μg/ml,术后用量为2.5μg·kg-1·d-1,连续灌服4周.(4)VD3+FK506组:术后联合应用骨化三醇及FK506,用药方法和用量与FK506组和VD3组相同.术后观察各组受者移植肢体排斥反应发生的时间和存活时间;流式细胞仪检测T淋巴细胞亚群CD4+、CD8+细胞的百分率.结果 对照组、FK506组、VD3组以及VD3+FK506组肢体移植后排斥反应发生的时间分别为:(3.50±0.50)d、(13.13±1.50)d、(10.63±0.38)d和(29.25±0.63)d;移植肢体的存活时间分别为:(8.50±0.50)d、(26.25±1.50)d、(17.25±0.38)d和(62.00±0.63)d;与对照组比较,VD3组排斥反应发生的时间和移植肢体的存活时间均明显延长,差异有统计学意义(P＜0.01);VD3+FK506组抗排斥反应效果更佳,与FK506组和VD3组比较,差异有统计学意义(P＜0.01).VD3组T淋巴细胞亚群CD4+/CD8+细胞的比值明显低于对照组,VD3+FK506组又明显低于VD3组和FK506组(P＜0.01).结论 骨化三醇能明显减轻同种肢体移植排斥反应,延长移植肢体的存活时间;骨化三醇与FK506联合应用效果更佳,二者具有协同作用.     

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.