表皮生长因子对人小细胞肺癌细胞Survivin表达的影响及其机制

目的 探讨表皮生长因子(EGF)对人小细胞肺癌NIC-H446细胞中凋亡抑制因子Survivin表达的影响及其调控Survivin的机制.方法 噻唑蓝(MTT)法测定EGF对细胞增殖率的作用.逆转录-聚合酶链反应(RT-PCR)和免疫印迹(Western blot)方法测定EGF对NIC -H446细胞Survivin表达的影响.Western blot方法测定EGF对NIC-H446细胞p38丝裂原活化激酶(p38MAPK)、磷酸化p38MAPK(p-p38MAPK)、c-Jun氨基端激酶(JNK)、磷酸化JNK (p-JNK)、细胞外信号调节蛋白激酶(ERK)、磷酸化ERK(p-ERK)信号通路蛋白的表达影响.结果 EGF可促进NIC-H446细胞增殖,具有浓度-时间依赖性.与对照组(0.36±0.06、0.57 ±0.15)比较,EGF组Survivin mRNA(0.69±0.12)和蛋白(0.89±0.19)表达明显升高(P＜0.01).与对照组(0.29±0.08)比较,EGF组p-p38MAPK蛋白表达水平(0.68±0.27)明显上升(P＜0.01),其他蛋白表达均无明显变化.EGF+ SB203580组Survivin蛋白表达(0.56±0.17)、p-p38MAPK蛋白表达(0.41±0.11)显著低于EGF组(0.92 ±0.21、0.72 ±0.19,P＜0.01),与对照组比较差异无统计学意义.结论 EGF通过活化p38MAPK信号通路上调小细胞肺癌细胞中Survivin的表达,促进细胞增殖,这可能是小细胞肺癌发展的重要机制.     

缺氧诱导因子-1α对体外模拟CO2气腹下人胃癌细胞凋亡的影响

目的 通过体外模拟CO2气腹环境,构建沉默缺氧诱导因子-1α(HIF-1α)的RNAi表达载体,探讨HIF-1α对CO2气腹环境下人胃癌细胞MKN-45凋亡的影响及机制.方法 利用密闭培养箱模拟CO2气腹,气腹机维持培养箱内压力分别为0、5、10、15 mm Hg(1 mm Hg=0.133 kPa),采用RT-PCR方法和Western blot方法观察沉默HIF-1α前后MKN-45细胞HIF-1α mRNA和蛋白表达变化.免疫组化技术观察沉默HIF-1α前后细胞bcl-2/bax表达变化.Annexin V-FITC/PI舣标染色、流式细胞仪检测沉默HIF-1α前后细胞凋亡比例变化.结果 沉默HIF-1α前15 mm Hg组细胞HIF-1α mRNA和蛋白表达(1.48±0.22和1.34±0.09)以及10 nnn Hg组细胞蛋门表达(1.25±0.10)均显著高于对照组(0.55±0.17和0.83±0.04)(P＜0.05).0、5、10 mm Hg组细胞HIF-1α mRNA和0、5 mm Hg蛋白表达与对照组比较差异无统计学意义(P＞0.05).沉默HIF-1α前15 mm Hg组细胞bcl-2/bax比值(0.78±0.05)较对照组(1.43±0.15)明显降低(P＜0.05),细胞凋亡比例(11.70±0.12)较对照组(0.22±0.07)显著增加(P＜0.01).而在沉默HIF-1α后15 mm Hg组细胞HIF-1α mRNA表达(0.52±0.11)和蛋白表达(0.92±0.02)、bcl-2/bax比值(1.57±0.04)、细胞凋亡比例(0.45±0.11)与对照组比较均无显著差异(P＞0.05).结论 在CO2气腹环境压力为0、5、10 mmHg CO2时MKN-45细胞凋亡比例与对照组比较无显著差异,压力为15 mm Hg时CO2气腹可促进胃癌细胞凋亡,HIF-1α可能为促进细胞凋亡的重要因子.     

细胞外信号调节激酶和P38蛋白激酶在自体移植静脉中的表达

目的研究丝裂原活化蛋白激酶亚单位细胞外信号调节激酶(ERK)和p38蛋白激酶(p38 MAPK)在移植静脉血管重塑过程中的表达.方法选Wistar大鼠80只,建立自体移植静脉模型,术后随机分为6 h、24 h、3 d、7 d、2周、4周、6周及8周组,于相应时点取材,半定量逆转录PCR法检测移植血管中ERK和p38 MAPK的mRNA表达;Western蛋白印迹定量检测ERK和p38 MAPK的蛋白产物及磷酸化蛋白产物表达;脱氧核苷酸末端转移酶末端标记法(TUNEL)检测血管平滑肌细胞(VSMC)凋亡的变化;免疫组化检测增殖细胞核抗原(PCNA)的表达.结果移植静脉术后6 h,ERK1和p38 MAPK的mRNA表达均明显增强,与正常静脉组比较差异均有显著性意义(P＜0.01);ERK1mRNA表达在移植后7 d达高峰,表达值为(33.2±14.2)%,p38 MAPK的mRNA表达于术后2周达到高峰,表达值为(58.8±26.2)%,与其余各时点比较差异有显著性意义(P＜0.01).Western蛋白印迹提示ERK1/2在术后1～2周达高峰,6周时逐渐恢复至正常水平;而p38 MAPK则在移植后2～4周达高峰,之后开始减少,8周时仍维持一定表达量(1/4～1/2).ERK1与PCNA表达呈正相关(r=0.759 6,P＜0.01),p38 MAPK与凋亡呈正相关(r=0.892 2,P＜0.01).结论MAPK的激活是移植静脉内膜增生以及血管重塑的关键环节,可能成为防治移植静脉狭窄、闭塞的新的治疗靶点.     

灯盏细辛对大鼠肾冷缺血再灌注损伤中细胞凋亡的影响

目的 观察中药灯盏细辛对大鼠肾脏冷缺血再灌注损伤(IRI)中肾脏细胞凋亡及相关基因表达的影响.方法 封闭群SD大鼠36只,随机分为3组,每组12只.假手术组(A组),对照组(B组),实验组(C组).药物应用:C组术前15 min,灯盏细辛注射液按1.2 ml/100 g通过尾静脉注射,A、B组按相应剂量注射生理盐水.动物手术:A组,切除右肾.B、C组采用的是冷IRI模型,3组大鼠均在术后24h再次手术切除左肾进行检测.透射电镜检查肾组织形态学,免疫组织化学检测凋亡相关的基因bcl-2与bax的表达,原位末端标记法(TUNEL)检测细胞凋亡.结果 (1)超微结构检查(透射电镜):A组结构正常;B组细胞呈损伤形态:线粒体肿胀,微绒毛减少,胞质内空泡形成,部分细胞核可见凋亡迹象.C组病变较B组显著减轻.(2)免疫组织化学蛋白阳性染色指数(PI):缺血再灌注后B、C组的bcl-2表达分别为(21.21±1.18)％和(35.52±1.94)％,较A组(4.95±0.77)％均增多(P＜0.05),B组低于C组(P＜0.05).B、C组的bax表达分别为(58.55±2.90)％和(45.90±3.14)％,较A组(4.67±0.67)％增多(P＜0.05),而且B组高于C组(P＜0.05).A组的蛋白阳性染色指数的比值bcl-2/bax为(1.06±0.07)高于B组(0.35±0.03)和C组(0.78±0.07,P＜0.05),而且C组高于B组(P＜0.05).(3)细胞凋亡检测(TUNEL):细胞凋亡指数B组(28.57±3.58)％和C组(19.99±3.37)％均显著大于A组(2.33±0.42)％(P＜0.01),C 组小于B组(P＜0.01).结论 灯盏细辛减少大鼠肾脏冷IRI诱导的肾脏细胞的凋亡,与调节凋亡相关基因bcl-2与bax表达有关.     

热休克蛋白70对大鼠离体心脏细胞凋亡的影响

目的 观察热休克蛋白70(HSP70)对离体大鼠供心心肌细胞凋亡相关蛋白bcl-2、bax表达的影响.方法 Wistar大鼠18只,分为2组:对照组(C,n=9),腹腔注射生理盐水0.5 ml,24 h后取离体心脏灌注HTK心脏保护液,4 ℃保存3 h后建立Langendorff离体心脏灌注模型,灌注KH液2 h;实验组(E,n=9)腹腔注射重酒石酸去甲肾上腺素(溶于生理盐水中)3.1 μmol/kg(0.53 mg/kg),腹腔注射24 h后取离体心脏,处理方法旧C组.运用免疫组织化学SP法测定心肌HSP70含量、bcl-2、bax蛋白的含量并做统计学处理比较.结果 HSPT0含量E组(17.78±1.82)较C组(5.22±1.05)明显增高(P＜0.01),bel-2的表达E组(41.88±5.09)较C组(31.36±3.27)明显增多(P＜0.01),bax的表达E组(22.61±3.49)较C组(40.52±4.17)明显减少(P＜0.01),bel-2/bax比值E组(1.86±0.11)较C组(0.77±0.01)明显增高(P＜0.05).结论 心肌HSP70高表达能促进心肌抗凋亡蛋白bcl-2的表达,减少促凋亡蛋白bax表达,增加bel-2/bax比率,抑制心肌细胞凋亡.     

高压氧对精索静脉曲张大鼠生精细胞凋亡及其基因缺氧诱导因子-α、bcl-2及bax表达的影响

目的 观察高压氧(HBO)对精索静脉曲张(VC)SD大鼠生精细胞凋亡的影响,探讨精索静脉曲张导致男性不育的机制.方法 50只青春期雄性SD大鼠,随机抽出10只作为假手术对照组(A).A组只游离左肾静脉不予结扎,其余40只部分结扎左肾静脉建立VC模型,8周后,将建立了VC模型的40只随机分为VC模型组(B)和HBO干预的VC模型组(C),C组用HBO对VC模型进行干预.实验结束后各组大鼠切取双侧睾丸,采用原位末端标记法(TUNEL)检测大鼠睾丸生精细胞凋亡,免疫组织化学检测低氧诱导因子(HIF)-α、bcl-2及bax的基因表达.结果 B组较A组生精细胞凋亡数明显增多,HIF-α、bax表达增强(P＜0.01),bcl-2表达减弱(P＜0.01),bcl-2/bax比值降低;C组大鼠较B组生精细胞凋亡数减少(P＜0.01),HIF-α表达减弱(P＜0.01)、bcl-2/bax比值上升,而与A组比较差异无统计学意义.结论 VC大鼠生精细胞凋亡率增加,HIF-α表达增强、bcl-2和bax基因表达失调为其凋亡机制之一;高压氧可能通过HIF-α、bcl-2和bax基因调控途径调节生精细胞凋亡,从而改善VC所致的生精功能障碍.     

力学刺激对软骨细胞凋亡信号转导分子Caspase-3及bcl-2、bax mRNA表达的影响

目的 观察力学刺激对软骨细胞凋亡信号转导分子半胱氨酸酶-3( Caspase-3)及B细胞淋巴瘤-2(bcl-2)、bax mRNA表达和凋亡的影响.方法 兔膝关节软骨分离培养,在第3代软骨细胞培养瓶中加入不同剂量的Caspase-3、bcl-2、bax抑制剂,力学刺激诱导凋亡,然后检测软骨细胞凋亡率,聚合酶链反应(PCR)半定量分析Caspase-3 bcl-2、bax mRNA表达.结果 力学刺激诱导软骨细胞凋亡,在加入抑制剂的各组和空白组的凋亡率差异有统计学意义(P＜0.05);各组Caspase-3及bcl-2、bax mRNA表达和空白组差异有统计学意义(P＜0.05).Caspase-3抑制剂组的凋亡率和Caspase-3表达明显相关(r=0.69,t=3.41,P＜0.01);bcl-2抑制剂组和bcl-2的表达明显相关(r=0.73,t=3.97,P＜0.01);bax抑制剂组和bax的表达明显相关(r=0.89,t =6.69,P＜0.01);各组差异均有统计学意义.结论 Caspase-3、bax抑制剂能对抗力学刺激诱导的凋亡,而bcl-2抑制剂使凋亡增加,各组Caspase-3及bcl-2、bax mRNA表达发生相应改变.     

缺氧诱导因子1α对CO2气腹环境下人胃癌细胞凋亡的影响

目的 通过体外模拟CO2气腹环境,构建沉默缺氧诱导因子1α(HIF-1α)的RNAi表达载体,探讨HIF-1α对CO2气腹环境下人胃癌细胞MKN-45凋亡的影响及机制.方法 利用密闭培养箱模拟CO2气腹,气腹机维持培养箱内压力分别为0、5、10、15mm Hg.采用荧光定量RT-PCR方法和Western blot方法观察沉默HIF-1α前后MKN-45细胞HIF-1α mRNA和蛋白表达的变化;免疫细胞化学技术观察沉默HIF-1α前后细胞bcl-2/bax表达的变化;Annexin V-FITC/PI双标染色、流式细胞仪检测沉默HIF-1α前后细胞凋亡比例的变化.结果 沉默HIF-1α前15 mm Hg组细胞HIF-1αmRNA和蛋白表达(分别为1.51±0.04、4.44±0.30)均显著高于对照组(0.584±0.06、2.01±0.06)(P<0.01).沉默HIF-1α前15mmHg组细胞bcl-2/bax比值(0.77±0.05)较对照组(1.43±0.02)明显降低(P<0.05),细胞凋亡比例(11.60±2.11)较对照组(0.30±0.02)增加.而在沉默HI-1α后15 mm Hg组细胞HIF-1α mRNA(0.464±0.04)和蛋白表达(0.92±0.02)、bcl-2/bax比值(1.61±0.04)、细胞凋亡比例(0.4±0.03)与对照组相比差异均无统计学意义(P>0.05).结论 在CO2气腹环境压力为0、5、10mm Hg CO2时MKN-45细胞凋亡比例与对照组比较无差异,压力为15mm Hg时CO2气腹可促进胃癌细胞凋亡.HIF-1α可能为促进细胞凋亡的原因之一.     

机械牵张对A549细胞穿透素-3表达的影响

目的 探讨械牵张对肺泡上皮腺癌细胞A549(A549细胞)穿透素-3(PTX-3)表达的影响.方法 体外培养人A549细胞,将A549细胞接种于包被胶原基底膜的培养板上,待细胞贴壁并融合50%后,随机分为正常对照组(Ⅰ组)、假机械牵张组(Ⅱ组)、机械牵张组(Ⅲ组)、siRNA对照组(Ⅳ组)和siRNA+机械牵张组(V组).Ⅳ组仅转染PTX-3 siRNA;Ⅴ组转染PTX-3 siRNA后24 h,进行周期性机械牵张4 h.机械牵张结束后24 h时测定PTX-3 mRNA、PTX-3蛋白水平及细胞凋亡情况.结果 与Ⅰ组和Ⅱ组比较,Ⅲ组PTX-3 mRNA和PIX-3蛋白水平上调,Ⅳ组和Ⅴ组上述两指标下调(P＜0.05或0.01);与Ⅲ组比较,Ⅴ组上述两指标下调(P＜0.01).Ⅲ组和Ⅴ组细胞凋亡率高于Ⅱ组(P＜0.01);Ⅴ组细胞凋亡率低于Ⅲ组(P＜0.01).结论 机械牵张可上调A549细胞PTX-3 mRNA表达.     

羟考酮与吗啡对体外培养肺腺癌A549细胞的影响

目的比较羟考酮与吗啡对体外培养肺腺癌A549细胞增殖、凋亡、迁移的影响,并探讨其可能机制。方法采用不加药培养基(C组)及加入不同浓度羟考酮[10μg/ml(Q1组)、20μg/ml(Q2组)、40μg/ml(Q3组)]和吗啡(10μg/ml(M1组)、20μg/ml(M2组)、40μg/ml(M3组)]培养基培养肺腺癌A549细胞。显微镜下观察A549细胞形态学改变;四甲基偶氮唑盐(MTT)法检测细胞体外增殖情况;流式细胞术检测细胞早期凋亡率;划痕实验检测细胞迁移能力;逆转录聚合酶链式反应(RT-PCR)法检测凋亡相关分子P53、bax和bcl-2的mRNA表达;ELISA法测定血管内皮生长因子(VEGF)及尿激酶纤维蛋白溶酶原激活物(uPA)的表达。结果羟考酮和吗啡处理后,A549细胞均出现凋亡;两者均剂量依赖性地抑制A549细胞增殖,且羟考酮的抑制作用比吗啡更明显(P0.05);两者均剂量依赖性地促进A549细胞凋亡率(P0.05),但两者差异无统计学意义;羟考酮剂量依赖性抑制细胞迁移,而吗啡促进细胞迁移(P0.05);两者均剂量相关性地上调细胞P53mRNA、bax mRNA的表达,下调bcl-2mRNA的表达(P0.05);二者均抑制细胞VEGF的表达,且羟考酮的抑制作用比吗啡更明显(P0.05);羟考酮抑制细胞uPA的表达,而吗啡促进细胞uPA的表达(P0.05)。结论羟考酮比吗啡更抑制A549细胞增殖,促进其凋亡,减弱其迁移,这可能与羟考酮调控P53、bax和bcl-2mRNA的水平和VEGF、uPA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.