上皮-间质转化是肝动脉断流后肝癌侵袭转移潜能增加的重要机制

目的 研究肝动脉断流对原发性肝癌(简称肝癌)侵袭转移潜能的影响.方法 采用24只 BALB/c-nu/nu裸鼠,建立转移性人肝癌裸鼠原位移植模型.种瘤术后2周荷瘤裸鼠随机分为2组干预:一组行肝动脉结扎(hepatic artery ligation,HAL);另一组假手术作为对照.每组随机抽取6只裸鼠于干预术后4周进行肿瘤大小和肺转移率的比较,并用免疫组化(S-P法)及Western blot检测移植瘤上皮-间质转化(epithelial-mesenchymal transition,EMT)相关分子的表达;其余荷瘤动物观察生存时间.体外以100 μmol/L CoCl2模拟乏氧环境,观察MHCC97L肝癌细胞生长和凋亡以及运动和侵袭能力,用免疫荧光和Western blot检测细胞EMT标志分子的变化.结果 HAL抑制肝癌生长[(1996.8±223.6)mm3比(4049.1±596.5)mm3,P＜0.01],但增加肺转移率(6/6比1/6,P＜0.05),因此不能改善荷瘤动物生存期[(56.0±4.6)d比(60.7±5.8)d,P＞0.05].这与乏氧环境中癌细胞运动[(472.7±84.3)μm比(378.8±73.7)μm,P＜0.05]和侵袭能力[(154.4±30.5)个比(45.2±7.6)个,P＜0.01]增强有关,主要涉及E-cadherin下降及N-cadherin和Twist上调的EMT机制.结论 HAL抑制肝癌生长,促进其侵袭转移潜能,与乏氧环境中癌细胞EMT相关.     

抑制残癌细胞上皮间质转化能降低肝动脉结扎增强的肝癌转移潜能

目的 探讨抑制残癌细胞上皮-间质转化对肝动脉断流后肝癌增强的转移潜能的影响.方法 采用MHCC97肝癌细胞系和52只BALB/c-nu/nu裸鼠,建立转移性人肝癌裸鼠原位移植并肝动脉结扎(hepatic artery ligation,HAL)模型.另12只荷瘤裸鼠行假手术设为对照.分别观察肝动脉结扎+阻滞剂LY294002以及肝动脉结扎+不同剂量干扰素α(intererin-α,IFN-α)对移植瘤生长和肺转移率的影响.体外将肝癌细胞MHCC97置于缺氧环境中培养.Western blot检测细胞和移植瘤内HIF-1 α、E-cadherin、N-cadherin、Twist表达.结果 肝动脉结扎虽然减小肝癌移植瘤体积(2002.97 ±331.28) mm3 vs.(3921.23 ±786.21) mm3,t =4.052,P＜0.01),但增加荷瘤裸鼠肺转移率( 10/12 vs.4/12,P＜0.05).联合阻滞剂LY294002治疗不能进一步抑制肝癌生长,但显著减少裸鼠肺转移(1/6 vs.10/12 vs.100％,P＜0.05).中等以上剂量的IFN-α(7.5×106 U/kg)显著降低肝动脉结扎诱导的肺转移率(0/6 vs.2/6 vs.100％,P＜0.01,P＜0.05).对移植瘤和细胞样本的分析证实阻滞剂LY294002或中等以上剂量的IFN-α均抑制缺氧肝癌细胞内N-cadherin和Twist上调,增加E-cadherin表达.结论 阻断肝癌细胞上皮-间质转化能够抑制缺氧诱导的肝癌侵袭、转移.     

肝动脉结扎对转移性人肝癌裸鼠原位移植瘤乏氧的影响

目的 观察肝动脉结扎(HAL)对转移性人肝癌裸鼠原位移植瘤乏氧的影响.方法 采用24只BALB/C-nu/nu裸鼠,建立转移性人肝癌裸鼠原位移植模型;随机分为2组,A组于移植瘤术后2周进行HAL(n=12),B组假手术(Sham)作为对照(n=12).分别于干预术后2 d和4周各随机处死每组中6只荷瘤裸鼠,利用免疫组织化学显色(SP法)和Western blot检测移植瘤内哌莫硝唑(Pimonidazole)和缺氧诱导因子(HIF)-1α的阳性表达和染色强度,以及血管内皮生长因子(VEGF)蛋白水平和肿瘤组织微血管密度(MVD),并用肺连续切片法计数4周时荷瘤裸鼠肺转移灶.结果 与Sham组比较,HAL组移植瘤内Pimonidazole阳性细胞及HIF-1α表达水平在术后2 d显著增加(P<0.05),并且肿瘤组织和血清内VEGF水平[(922.5±59.3)比(349.6±46.5)ng/L,P<0.01]明显增加.术后4周,荷瘤裸鼠肺转移率较对照组增加(6/6比1/6,P<0.05),但此时乏氧细胞,VEGF表达和MVD则与对照组比较差异无统计学意义(P>0.05).结论 HAL促进转移性人肝癌裸鼠原位移植瘤短期乏氧及VEGF表达,但不影响移植瘤长期乏氧效应.     

转移性人肝癌裸小鼠原位种植合并肝动脉结扎模型的建立

目的 建立稳定有效的转移性人肝癌裸小鼠原位种植合并肝动脉结扎模型.方法 采用56只BALB/C-nu/nu裸小鼠,建立转移性人肝癌裸小鼠原位种植模型;随机分为2组,移植瘤术后2周进行肝动脉结扎(HAL)组和仅开腹为假手术组.两组中各随机抽出6只裸鼠,在2次手术后2 d利用哌莫硝唑(PimoIlidazole)作为乏氧探针行肝脏移植瘤标本免疫组织化学显色和Western blot检测移植瘤组织中乏氧诱导因子(HIF)-1α蛋白的表达.结果 人肝癌裸小鼠原位种植成瘤率为100.0%(56/56);HAL手术成功率达93.3%(28/30);与假手术组比较,HAL组移植瘤内乏氧细胞(Pimonidazole阳性细胞)显著增加(P＜0.05),移植瘤组织HIF-1α蛋白表达升高(P＜0.05).结论 转移性人肝癌裸小鼠原位种植合并肝动脉结扎模型手术成功率高,能够导致肝脏移植瘤有效乏氧,是一种较理想的研究肝动脉断流对人肝癌生物学特性影响的实验模型.     

肝动脉断流促进癌旁正常肝细胞上皮-间质转化

目的 观察肝动脉断流对癌旁正常肝细胞生物学特性的影响.方法 肝动脉结扎(HAL)阻断裸鼠肝脏原位移植瘤(高转移性MHCC97H肝癌细胞)血供(nHAL=10,n假手术=10).免疫组织化学(SP)法分别检测移植瘤内或癌旁缺氧诱导因子-1α(HIF-1α)、Pimonidazole及上皮-间质转化(EMT)标记分子如E-cadherin和N-cadherin分子表达;体外用CoCl2模拟缺氧环境,免疫荧光和Western blot检测缺氧处理后L-02肝细胞内上述分子的表达变化.结果 HAL增加肝癌组织和癌旁肝组织内HIF-1α表达和Pimonidazole阳性细胞数(HAL组:9±3比假手术组:4±2,P＜0.05),减少癌旁肝细胞内E-cadherin水平,增加其N-cadherin蛋白表达.100 μmol/L CoCl2有效模拟体外缺氧环境,增加L-02肝细胞内HIF-1α表达,上调N-cadherin同时降低E-cadherin表达.结论 HAL 增加肝癌及癌旁组织缺氧,诱导癌旁正常肝细胞发生EMT.     

缺氧诱导因子1α表达对裸鼠肝癌皮下移植瘤生长的促进作用

目的 探讨缺氧诱导因子1α表达对肝癌移植瘤生长的影响.方法 建立强力霉素诱导缺氧诱导因子1α表达的裸鼠肝癌HepG2 Tet-on-HIF-1α 细胞皮下移植瘤模型;荷瘤裸鼠口服强力霉素(Dox)后,观察上调缺氧诱导因子1α对皮下移植瘤生长的影响.结果 荷瘤裸鼠口服强力霉素可以上调裸鼠皮下移植瘤中缺氧诱导因子1α mRNA和蛋白表达水平;肿瘤体积Dox(+)组vs.Dox(-)组为(513.545±276.229)mm 3 vs.(166.506±110.142)mm 3 (P<0.05),肿瘤重量(1.251±0.438)g vs.(0.640±0.296)g(P<0.05),肿瘤生长速度Dox(+)组明显超过Dox(-)组,肿瘤内面积坏死率明显小于Dox(-)组(31.360%±2.728%)vs.(36.640±3.804%)(P<0.05);同Dox(-)组相比,Dox(+)组裸鼠体重下降更为明显(P<0.01).两组荷瘤鼠均无肝、肺转移发生.结论 强力霉素可以诱导裸鼠肝癌HepG2 Tet-on-HIF-1α 细胞皮下移植瘤模型中缺氧诱导因子1α的表达,促进肿瘤的生长.     

干扰素-α抑制高转移潜能人肝癌裸鼠肝细胞生长因子及血管内皮生长因子的表达

目的 观察干扰素-α(IFN-α)对高转移潜能人肝癌裸鼠模型中血管内皮生长因子(VEGF)、肝细胞生长因子(HGF)mRNA表达的影响.方法 应用绿色荧光蛋白转染的人高转移肝癌细胞株HCC-LM3建立高转移潜能人肝癌裸鼠模型LCI-D20,种植后第2天开始分别使用IFN-α 1.5×104 U/(kg·d)(治疗组,n=12)或生理盐水(对照组,n=12)皮下注射,28 d后处死裸鼠,比较肝脏肿瘤的大小和肝内转移,免疫组织化学检测肿瘤微血管密度(MVD),实时荧光定量聚合酶链反应(PCR)检测肿瘤HGF和VEGF表达的变化.结果治疗组、对照组的肝内肿瘤大小分别为(0.11±0.03)cm3、(0.99±0.37)cm3(P<0.05);肝内转移率分别为33.3%(4/12)、83.3%(10/12)(P<0.05);肝内转移数目分别为0.67±0.31个比1.91±0.43个(P<0.05);肿瘤内MVD分别为3.19±0.52、4.85±0.72(P<0.05);肿瘤VEGF mRNA表达(-△CT)分别为-8.16±0.54、-6.95±0.86(P<0.05);HGF mRNA表达分别为-11.62±0.63、-10.56±0.48(P<0.05).结论 IFN-α对HGF及VEGF表达的抑制可能是其抗肿瘤血管生成作用、抑制肿瘤生长转移作用的机制之一.     

肝动脉阻断对大鼠肝癌血供与VEGF、MMP表达的影响

目的　观察肝动脉阻断对大鼠移植性肝癌的血液灌流与血管内皮生长因子 (VEGF)、基质金属蛋白酶 1(MMP 1)表达的影响 ,初步探索肝动脉栓塞促进肝癌转移的机制。方法　采用大鼠肝内移植Walker 2 5 6肿瘤模型 ,以肝动脉结扎 (HAL)的方法阻断肝动脉血供 ,模拟肝动脉栓塞治疗。分为对照组、剖腹对照组、HAL组。Hoechst33342标记法检测瘤组织血液灌流 (标记细胞数代表血供情况 ) ,酶联免疫吸附试验 (ELISA)测定血清VEGF水平 ,原位杂交法检测瘤组织VEGF、MMP 1表达。结果　HAL后 2d瘤组织血供明显下降 (对照组每高倍视野Hoechst33342标记细胞数 383 6± 19 2 ,HAL组 32 9 1± 2 9 3 ,P <0 0 1)。血清VEGF水平明显升高 (对照组 5 4 9± 19 3pg ml,HAL组 92 5± 43 9pg ml,P <0 0 5 )。瘤组织VEGF、MMP 1mRNA表达水平较对照组、剖腹对照组明显升高 (P <0 0 5 )。瘤组织血供与血清VEGF水平、瘤组织VEGF表达负相关。结论　肝动脉阻断使癌组织血供减少 ,转移相关基因VEGF、MMP 1表达升高。血供减少、缺氧加重可能为其诱导VEGF表达的主要机制。     

赛来昔布对人骨肉瘤类肿瘤干细胞移植瘤微血管生成的影响

[目的] 探讨cox-2抑制剂赛来昔布(Celecoxib)对骨肉瘤类肿瘤干细胞裸鼠移植瘤生长及微血管生成的影响.[方法] 无血清堵养法从骨肉瘤细胞株MG-3中分离出类肿瘤干细胞建立裸鼠移植瘤模型.30只成瘤裸鼠随机分 Celecoxib 组和对照组,Celcoxib:25 mg/ (kg·d),用药15 d,第27 d处死裸鼠,观察肿瘤体积、抑瘤率,免疫组化技术检测VEGF表达及CD34标记的MVD值.[结果] 分离的骨肉瘤类肿瘤干细胞有致瘤性,可以建立动物模型.Celecoxib抑瘤率为23.2%,Celecoxib组裸鼠移植瘤的体积、VEGF的表达、MVD值均显著低于对照组(P＜0.05).[结论] 骨肉瘤类肿瘤下细胞可以建立裸鼠骨肉瘤移植瘤模型.Celeeoxib可以抑制肿瘤生长,减少移植瘤组织VEGF的表达,减少微血管生成,具有抗血管生成作用.     

5-LOX抑制剂NDGA对人肝癌HepG-2细胞裸鼠移植瘤生长的影响及其机制的探讨

目的观察5-lox抑制剂去甲二氢愈创木酸(NDGA)对裸鼠人肝癌HepG-2细胞移植瘤的作用,并探讨其抗肿瘤的可能机制。方法以人肝癌细胞HepG-2制备裸鼠人肝癌移植瘤模型共18只,将18只荷瘤裸鼠随机分为三组:1、正常对照组(接种正常肝癌HepG2细胞)。2、药物组(接种正常肝癌HepG2细胞同时皮下注入5-lox抑制剂去甲二氢愈创木酸(NDGA),剂量:10μml/L NDGA 0.1ml/10g一天一次,连续5天)。3、溶媒组(接种正常HepG-2细胞后皮下注射溶质二甲亚酚)。密切观察移植瘤生长及裸鼠生存情况21天,记录各组移植瘤肿瘤体积V(V=长径×短径2×0.5),计算衰退率:肿瘤衰退率=1-干预组平均肿瘤体积比/空白对照组平均肿瘤体积比(V/Vo)。通过RT-PCR及Western-blot法检测裸鼠移植瘤组织中bcl-2、caspase3凋亡调节因子以及通路信号蛋白MEK1/2、ERK1/2等的表达。结果实验期间各组荷瘤鼠活动较好,成瘤率100%,且实验过程中无不良繁衍及裸鼠死亡;试验后分别测得各组荷瘤鼠皮下移植瘤体积及肿瘤衰退率,利用单因素方差分析及t检验可以发现:药物组荷瘤鼠较对照组及溶媒组移植瘤体积明显缩小,肿瘤衰退率明显较高,且存在统计学差异(P0.01);利用RT-PCR及Western-blot法检测发现药物组caspase3表达量较对照组及溶媒组明显增强,差异存在统计学意义(P0.01),bcl-2、ERK1/2、MEK1/2等表达量较对照组及溶媒组明显下降,差异具有统计学意义(P0.01)。结论 NDGA对于裸鼠人肝癌移植瘤具有明显的抑制效果。NDGA可能通过诱导肿瘤细胞凋亡而抑制肿瘤生长,其作用机制与抑制MEK/ERK信号通路有关。     

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.     

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.