维生素C对大鼠肾结石模型体内活性氧及成石的影响

目的　观察不同剂量维生素C(VitC)对大鼠肾结石模型体内活性氧 (ROS)的影响及VitC、ROS与肾结石形成的关系。　方法　用乙二醇诱导Wistar大鼠产生肾草酸钙结石。 30只大鼠分为正常组 ,成石组 ,治疗组 (分三个不同剂量 ,VitC 2 5、10 0、4 0 0mg·kg-1·d-1) ,喂养 15d。测定血和右肾组织中丙二醛 (MDA)、过氧化氢酶 (CAT)、超氧化物歧化酶 (SOD)、谷胱甘肽过氧化物酶(GSH Px)含量 ;左肾冰冻切片 ,偏光显微镜观察结晶情况。　结果　成石组血和组织中的MDA分别为 (43.89± 5 .10 )nmol/ml和 (6 .2 0± 2 .0 0 )nmol/gpr,较正常组增高 ,差别有显著性意义 (P <0 .0 1和P <0 .0 0 1) ,而抗氧化酶显著降低 (P <0 .0 1和P <0 .0 0 1)。VitC 4 0 0mg·kg-1·d-1治疗组血MDA(30 .80± 4 .6 9)nmol/ml,较成石组降低 (P <0 .0 5 ) ,与正常组比较差别无显著性意义 (P >0 .0 5 ) ,血SOD较成石组降低 (P <0 .0 5 ) ,血CAT、GSH Px较成石组升高 (P <0 .0 1) ;VitC 4 0 0mg·kg-1·d-1治疗组肾组织中MDA(11.96± 2 .4 4 )nmol/gpr ,较成石组升高 (P <0 .0 5 ) ,SOD较成石组升高 (P <0 .0 5 ) ,CAT、GSH Px较成石组有所降低。肾组织晶体形成与VitC剂量呈正相关 (r =0 .6 6 85 ,P <0 .0 1)。　结论　高草酸尿可使机体活性     

雄激素对前列腺癌细胞内游离钙离子浓度的影响

目的 探讨5α-双氢睾酮(DHT)对前列腺癌LNCaP细胞内游离钙离子浓度([Ca2+]i)的影响及其机制.方法 应用Fura-2/乙酸甲酯(Fura-2/AM)Ca2+荧光探针法结合MiraCal荧光成像系统实时检测不同浓度的DHT刺激以及Ca2+通道阻滞剂干预后LNCaP细胞[Ca2+]i的变化.结果 DHT能快速诱导[Ca2+]i升高,在20 s～3 min升至峰值.DHT浓度为1、10、100和1000nmol/L时能诱导[Ca2+]i分别从基础值(28±5)、(29±5)、(28±4)和(28±9)nmol/L上升至峰值31±3(P＞0.05)、65±9(P＜0.01)、193±33(P＜0.001)和(208±42)nmol/L(P＜0.001).DHT浓度为100和1000 mol/L时,[Ca2+]i峰值间差异无统计学意义(P＞0.05).细胞外液无Ca2+时,1000 nmol/L DHT未能诱导[Ca2+]i升高.细胞膜L-型电压门控Ca2+通道阻滞剂维拉帕米(50μmol/L)、地尔硫卓(100 μmol/L)或硝苯地平(5 mmol/L)37℃孵育细胞5 min后,能完全抑制1000nmol/L DHT诱导的[Ca2+]i升高.磷脂酶C抑制剂新霉素(1 mmol/L)37 ℃孵育细胞5 min或兰尼定受体阻滞剂普鲁卡因(50 mmol/L)37℃孵育细胞3 min后,对1000 nmol/L DHT诱导的[Ca2+]i升高没有影响.结论 DHT可快速、剂量依赖性诱导LNCaP细胞[Ca2+]i升高;DHT诱导LN-CaP细胞[Ca2+]i的升高是细胞外Ca2+经细胞膜L-型电压门控Ca2+通道流入细胞内实现的,细胞内贮钙库未释放Ca2+.     

烧伤血清对大鼠心肌细胞钙稳态的影响

目的　观察烫伤血清对成年大鼠分离的心肌细胞游离钙浓度 [(Ca2 )i]及胞膜钙通道电流的影响 ,探讨烧伤引起的心肌细胞钙稳态变化。　方法　伤后 2、4、6h分离 30 %TBSAⅢ度烧伤SD大鼠血清 ,简称 2hBS、4hBS、6hBS ;逆行循环灌流、胶原酶消化分离心肌细胞 ;Fura - 2 /AM荧光染色法测定 [Ca2 ]i;膜片钳技术全细胞记录模式测定细胞膜钙通道电流。　结果　正常心肌细胞[Ca2 ]i为 (10 1.3± 2 1.3)nmol/L ,烧伤血清可使心肌细胞 [Ca2 ]i显著升高。 (P <0 .0 1) ,以 6hBS的作用最强 ;钙通道阻断剂异搏定 (30mmol/L)和肌浆网rynodine受体拮抗剂普鲁卡因 (2mmol/L)均非常显著地抑制 6hBS的作用 (P <0 .0 1) ,抑制率分别为 47.7%和 6 7.6 % ,后者强于前者 (P <0 .0 1) ,2hBS使峰值L型钙电流 (ICa -L)比对照组增加 5 0 80 % ;而 6hBS使峰值ICa -L增加 1 5 2 .5倍 ;峰值电流 -电压曲线显示烧伤血清明显增加各个去极化钳制电压下的ICa ,并使得最大激活电压提前 ;细胞外液灌洗可祛除烧伤血清对钙电流的作用。　结论　烧伤血清能使心肌细胞 [Ca2 ]i,和膜上钙通道电流显著升高 ,钙稳态变化可能是烧伤后心肌损害的一种细胞机制     

缺血再灌注对肾细胞内钙水平和细胞凋亡的影响

目的　观察缺血再灌注损伤对肾细胞游离钙 ([Ca2 ]i)水平和细胞凋亡的影响。　方法　 30只Wistar大鼠 ,分组建立急性缺血再灌注肾损伤模型 ,应用Fura 2 /AM荧光指示剂测定缺血再灌注大鼠肾细胞 [Ca2 ]i水平 ,流式细胞术检测肾细胞凋亡率。　结果　缺血再灌注 1、2、2 4h肾细胞Ca2 超载水平分别为 15 6 .2、181.6和 2 6 0 .6nmol/L ,与对照组 (10 9.7nmol/L)相比差异有统计学意义(P <0 .0 1) ;1、2、2 4h肾细胞凋亡率分别为 9.5 8%、9.79%和 11.2 3% ,与对照组 (1.5 1% )相比差异有统计学意义 (P <0 .0 5 )。缺血再灌注细胞Ca2 超载与肾细胞凋亡率有正相关趋势 (r =0 .83,P >0 .0 5 )。　结论　缺血再灌注肾细胞呈现Ca2 超载 ,与肾细胞凋亡率呈正相关趋势 ,提示肾细胞钙超载可能是再灌注损伤肾功能障碍的重要原因。     

糖尿病大鼠膀胱中P物质、神经生长因子表达及氧化应激状态的研究

目的 研究糖尿病大鼠膀胱中P物质、神经生长因子(NGF)的表达及氧化应激状态的改变. 方法雄性Wistar大鼠分3组:对照组(n=10),糖尿病组(n=10),治疗组(n=10,糖尿病大鼠胃管注入太得恩(R),100 mg·kg-1·d-1).8周后取出膀胱,RT-PCR法检测膀胱组织中NGF表达,免疫组化方法检测P物质及一氧化氮合酶(iNOS)的表达,采用生化方法检测过氧化氢酶(CAT)、过氧化物酶(SOD)和丙二醛(MDA)水平.结果 糖尿病组膀胱组织中NGF mRNA表达水平中位值(0.35)显著低于对照组(2.77,P＜0.05),P物质表达水平(9.83)显著低于对照组(28.81,P＜0.05),CAT及SOD水平(11.46,7.16 U/mg蛋白)显著低于对照组(16.01,21.436 U/mg蛋白,P＜0.05),iNOS及MDA水平(67.50,15.97 nmol/mg蛋白)显著高于对照组(0,7.95 nmol/mg蛋白,P＜0.05).治疗组膀胱组织中NGF mRNA表达水平中位值(1.84)显著高于糖尿病组(P＜0.05),P物质表达水平(20.75)显著高于糖尿病组(P＜0.01),CAT及SOD水平(14.47,16.641 U/rag蛋白)显著高于糖尿病组(P＜0.05),iNOS及MDA水平(13.20,10.99 nmol/mg蛋白)显著低于糖尿病组(P＜0.05).结论 氧化应激存在于糖尿病大鼠膀胱.NGF、P物质在糖尿病膀胱中低表达.太得恩能增强糖尿病大鼠膀胱中NGF及P物质表达,改善氧化应激状态.     

脂质胞壁酸诱导的延迟预适应对大鼠局灶性脑缺血/再灌注损伤的保护作用

目的　探讨脂质胞壁酸 (LTA)诱导的延迟预适应对大鼠局灶性脑缺血 /再灌注 (I/R)损伤的作用。方法　采用局灶性脑缺血 2h ,再灌注 12h或 2 4h的方法 ,预适应组大鼠缺血前 2 4h腹腔注射LTA 1mg/kg) ,检测脑组织再灌注 2 4h后组织含水量、超氧化物歧化酶 (SOD)和丙二醛(MDA) ,再灌注 12h后大鼠神经症状、组织中一氧化氮 (NO)的含量 ,同时用TUNEL染色法检测神经细胞的凋亡。结果　I/R组脑组织中SOD和MDA的含量分别为 (2 .72± 0 .3 8)kU /g蛋白和(1.83± 0 .3 3 ) μmol/g蛋白 ,LTA预适应组SOD活性和MDA的含量分别为(3 .68± 0 .40 )kU /g .蛋白和 (1.2 7± 0 .2 1) μmol/g蛋白 ,与I/R组比较差异有统计学意义 (P均 <0 .0 1) ;I/R组NO含量和凋亡百分率为 (3 4.4± 6.3 ) %、(0 .85 2± 0 .0 90 ) μmol/g蛋白 ,而LTA预适应组神经细胞的凋亡百分率和脑组织中NO含量为 (7.2± 3 .2 ) %、(0 .5 94± 0 .0 78) μmol/g .蛋白均较I/R有显著降低 (P均 <0 .0 1)。结论　LTA诱导的延迟预适应能显著减少大鼠脑组织再灌注损伤 ,减少组织坏死和细胞凋亡。其作用机制与减少脑I/R后自由基和NO毒性作用有关。     

BK通道对大鼠脑缺血再灌注损伤神经细胞内钙离子浓度及凋亡的影响

目的 观察BK通道对脑缺血再灌注损伤神经细胞内钙离子浓度([Ca2+]i)和对神经元凋亡的影响。方法 将108只SD大鼠随机分为假手术组(SS组,n=36)、脑缺血再灌注组(IR组,n=36)、脑缺血再灌注且脑室内Iberiotoxin(IBTX)处理组(IBTX组,n=36),分别比较各组在不同再灌注时间后神经功能缺损评分、脑梗死面积,利用激光共聚焦显微镜技术测定各组[Ca2+]i浓度,免疫组织化学和TUNEL法分别检测BK通道表达和神经元细胞凋亡。结果 IBTX处理组在再灌注24h后神经功能缺损评分为(2.17±0.44)明显高于IR组(1.83±0.42,P＜0.05);脑梗死体积(27.97±5.84)％明显大于SS组(22.83±4.74)％(P＜0.05);激光共聚焦显微镜结果显示:IBTX处理组24h点[Ca2+]i为(914.50 ±86.57) nmol/L较SS组(732.09 ±51.30) nmol/L明显升高(P＜0.01),TUNEL细胞凋亡检测显示IBTX处理组24h神经细胞凋亡率为(15.20±6.11)％,与IR组(10.49±1.91)％比较差异有统计学意义(P＜0.05),免疫组织化学结果显示缺血再灌注损伤后BK通道的表达增加,但组间比较差异无统计学意义(P＞0.05)。结论 在缺血状态下,BK通道对神经细胞具有保护作用,其机制很可能是通过降低神经细胞内钙离子浓度和减少细胞的凋亡。     

Cariporide对未成熟兔心肌缺血再灌注损伤的保护作用

目的　探讨甲磺酸苯甲酰胍类化合物Cariporide对未成熟兔心肌缺血再灌注损伤的保护作用及其机制。　方法　以离体灌注幼兔心脏为模型 ,将 2 4只幼兔心脏随机均分为对照组 (应用St.ThomasⅡ液 )和实验组 (应用Cariporide St .ThomasⅡ液 ) ,常温缺血 60min ,期间每 2 0min灌注 1次保护液 ,恢复灌注后 ,测定心率、心律、平均动脉压、冠脉流量、左心室收缩压、左心室舒张末压、左心室压力微分 (±dp/dt)和心肌酶。将另 6只幼兔的心肌单细胞悬液随机均分为基础 (未予缺氧处理 )、钙对照和钙实验组 (经缺氧、再复氧处理 ,钙实验组于缺氧时加入Cariporide 1μmol/L) ,用激光共聚焦显微镜测定心肌细胞内游离钙 ([Ca2 ]i)浓度 ,以钙荧光强度比值表示。　结果　与对照组相比 ,实验组缺血、再灌注后室颤发生率低 ,心肌酶漏出量少 ,平均动脉压、左心室收缩压、冠脉流量及±dp/dt均明显增加 ,左心室舒张压低。未成熟兔心肌细胞内 [Ca2 ]i浓度 ,钙实验组比钙对照组明显减少 (P <0 0 1) ,钙实验组与基础组差异无显著意义 (14 4 6± 12 8与 13 75± 10 2 ,P >0 0 5)。结论　Cariporide对未成熟心肌缺血再灌注损伤有保护作用 ,其机制是抑制心肌细胞内 [Ca2 ]i超载引起的缺血再灌注损伤     

Rxa对过氧化氢诱导人类肝细胞系Fas mRNA表达及Ca2+流变化影响的单细胞分析

目的　探讨Rxa对过氧化物所致肝细胞凋亡时细胞保护作用的可能分子机制。方法应用全细胞膜片钳单细胞逆转录聚合酶链反应 (RT PCR)技术进行Rxa对过氧化氢 (H2 O2 )诱导人类肝细胞系 (L0 2细胞 )FasmRNA表达的单细胞分析 ,应用全细胞膜片钳显微荧光单细胞浆游离钙浓度 ([Ca2 ]i)测量技术进行同期瞬时Ca2 流变化观察。用流式细胞术观察早期凋亡细胞指数。结果　H2 O2 作用于L0 2细胞 2h电泳图分析可见FasmRNA表达 ,[Ca2 ]i (1115 .2 8± 2 2 7.16 )nmol/L、早期凋亡细胞指数骤升为 16 .18± 0 .6 5 ;而同期Rxa处理组电泳图分析未见FasmRNA特异性扩增条带出现 ;[Ca2 ]i、早期凋亡细胞指数较低 (P <0 .0 1、P <0 .0 1)。结论　Rxa可能通过抗氧化和钙阻滞作用阻抑L0 2细胞胞浆段Fas信号传导途径的活化 ,发挥细胞保护作用。     

联合应用ATP和NGF对体外培养乳鼠脊髓神经元影响的研究

目的　探讨三磷酸腺苷 (ATP)和神经生长因子 (nervegrowthfactor ,NGF)联合使用时对体外培养的乳鼠脊髓神经元的作用。　方法　利用神经细胞培养技术 ,根据不同干预分为NGF组、ATP组、ATP加NGF组以及单纯对照组。相差倒置显微镜观察细胞生长情况 ,并测量细胞突起的长度 ;用MTT法测定培养细胞的存活率。　结果　实验各组神经元的存活率和轴突的长度均明显优于对照组 ,差异有非常显著性 (P <0 .0 1)。比较MTT值 :ATP组与ATP加NGF组之间差异有非常显著性 (t =4.2 5 ,P <0 .0 1) ;NGF组与ATP加NGF组之间差异有显著性 (t =3 .5 0 3 ,P <0 0 5 )。比较细胞突起长度 :ATP加NGF组分别与ATP组、NGF组之间差异有非常显著性 (P <0 .0 1)。　结论　ATP、NGF对于体外培养的脊髓神经元的存活均有较强的维持作用 ,并能促进轴突生长 ;而两者联合使用作用明显增强。     

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.