长链非编码RNA RUSC1-AS1对肝细胞癌恶性生物学行的影响及其与微小RNA-326的关系

背景与目的:有研究表明长链非编码RNARUSC1-AS1(lnc RNARUSC1-AS1)与肿瘤的恶性生物学行为密切相关,但其对肝细胞癌(肝癌)的影响尚不清楚。笔者前期研究显示,lnc RNARUSC1-AS1与微小RNA-326(mi R-326)存在结合位点,因此本研究探讨lnc RNARUSC1-AS1在肝癌中的表达,以及是否通过靶向mi R-326调控肝癌细胞生物学行为。方法:用q RT-PCR检测41例肝癌组织和对应癌旁组织中lnc RNARUSC1-AS1与mi R-326的表达。以lnc RNARUSC1-AS1表达抑制质粒/阴性对照质粒、mi R-326模拟物/阴性对照序列、mi R-326抑制物/阴性对照序列为工具,采用MTT法、Transwell法、流式细胞术、Westernblot法观察接受不同转染处理的MHCC97-H细胞的增殖能力、迁移和侵袭能力、凋亡以及相关蛋白表达的变化。采用荧光素酶报告实验分析lnc RNARUSC1-AS1和mi R-326的靶向关系,并用q RT-PCR验证。结果:与癌旁组织比较,肝癌组织中lnc RNARUSC1-AS1表达水平明显升高,mi R-326表达水平明显降低(均P0.05)。转染lnc RNARUSC1-AS1表达抑制质粒或mi R-326模拟物后,肝癌MHCC97-H细胞的增殖能力以及迁移与侵袭能力明显降低,细胞凋亡率明显升高,cyclinD1、MMP-2、MMP-9、Bcl-2蛋白表达水平明显降低,P21、Bax蛋白表达水平明显升高(均P0.05)。MHCC97-H细胞转染lnc RNARUSC1-AS1表达抑制质粒的同时mi R-326抑制物,前者对MHCC97-H细胞以上作用被取消(均P0.05)。双荧光素酶报告实验及q RT-PCR验证结果显示,mi R-326为lnc RNARUSC1-AS1的靶分子。结论:lnc RNARUSC1-AS1在肝癌中表达上调,其可通过靶向调控mi R-326的表达促进肝癌细胞的恶性生物学行。     

microRNA-25高表达与直肠癌细胞的侵袭和迁移的关系

目的:探讨micro RNA-25(mi R-25)在直肠癌细胞中的表达及作用。方法:检测多种不同直肠癌细胞中mi R-25的表达,并检测直肠癌细胞转染mi R-25前体(pre-mi R-25)上调mi R-25的表达或转染mi R-25抑制剂(anti-mi R-25)下调mi R-25的表达后生物学行为的变化。结果:与正常直肠黏膜组织比较,不同的直肠癌细胞中mi R-25的表达均不同程度的明显升高(均P0.05)。在mi R-25表达水平相对较低的直肠癌HR-834细胞中转染pre-mi R-25,在mi R-25高表达的直肠癌SW-837细胞中转染anti-mi R-25后,两种细胞的增殖、细胞周期、凋亡无明改变(均P0.05),但侵袭及迁移能力在HR-834细胞的明显增强,SW-837细胞减弱(均P0.05)。结论:mi R-25在直肠癌细胞中的表达升高,且其升高程度与细胞的侵袭和迁移能力密切相关。     

胃癌细胞中miR-455-3p的表达及其对增殖和凋亡的影响

目的:探讨mi R-455-3p在胃癌细胞中的表达及对胃癌细胞增殖和凋亡的影响。方法:用q RT-PCR检测mi R-455-3p在正常胃黏膜上皮细胞RGM-1及5种胃癌细胞系(AGS、Hs746T、MGC-803、SGC-7901及BSG-823)中的表达。将胃癌细胞mi R-455-3p模拟物后,分别用CCK8法检测细胞增殖,流式细胞术检测细胞凋亡,Western blot检测细胞p27 kip1、p21的蛋白表达,分光光度法检测细胞caspase酶活性。结果:mi R-455-3p在5种胃癌细胞系中的表达水平明显低于RGM-1细胞系,其中在AGS细胞中降低最为明显(均P0.05)。AGS细胞转染mi R-455-3p模拟物后,增殖能力明显降低而胞凋亡率明显升高,p27 kip1蛋白表达量明显升高,caspase-3与caspase-9相对活性明显升高(均P0.05),但p21蛋白表达量与caspase-8相对活性无明显改变(均P0.05)。结论:mi R-455-3p在胃癌细胞表达下调,增加其表达可抑制胃癌细胞增殖并促进凋亡,其机制可能与其上调p27 kip1表达及增强caspase-3、caspase-9活性有关。     

miR-204对TFAM的靶向调控作用及其对乳腺癌细胞生长与增殖的影响

目的:探讨乳腺癌细胞中miR-204对线粒体转录因子A(TFAM)的靶向调控作用及其与细胞生长、增殖的关系。方法:将人乳腺癌MDA-MB-231细胞分别转染mi R-204模拟物或miR-204抑制物,用real-time PCR和Western blot分别检测mi R-204与TFAM蛋白的表达;构建荧光酶报告基因质粒(mut-TFAM/wt-TFAM),将其与mi R-204模拟物或miR-204抑制物共转染MDA-MB-231细胞后检测荧光酶活性变化;构建pc DNA3.1/TFAM质粒,将其单独或与mi R-204模拟物共转染MDA-MB-231细胞后检测TFAM蛋白表达,并用MTT法和Brd U法检测细胞生长与增殖情况。结果:MDA-MB-231细胞转染mi R-204模拟物后mi R-204的表达明显升高,而TFAM蛋白表达明显降低,转染miR-204抑制物后则呈反向变化(均P0.05)。wt-TFAM与mi R-204模拟物共转染时荧光酶活性明显下降,与mi R-204抑制物共转染时荧光酶活性明显升高(均P0.05)。转染pc DNA3.1/TFAM后,MDA-MB-231细胞的TFAM m RNA及蛋白表达量明显上调,细胞生长与增殖能力明显升高(均P0.05);mi R-204模拟物后,MDA-MB-231细胞在TFAM表达降低的同时,细胞生长与增殖能力明显降低,而与pc DNA3.1/TFAM共转染后其上述作用均被部分抵消(均P0.05)。结论:mi R-204能靶向抑制乳腺癌细胞TFAM的表达,从而抑制乳腺癌细胞的生长与增殖。     

miR-137与胃癌侵袭能力的关系研究

目的:探讨胃癌组织mi R-137的表达及其与胃癌细胞侵袭能力间的关系。方法:用q RT-PCR检测胃癌组织与癌旁组织mi R-137的表达,分析mi R-13表达与胃癌临床病理特征的关系;分别用q RT-PCR与Transwell侵袭实验检测3种胃癌细胞(AGS、SGC7901、BGC823)及正常胃黏膜细胞(GES1)mi R-137的表达与穿膜。结果:胃癌组织中mi R-137表达量明显低于癌旁组织(P<0.05),mi R-137表达与胃癌患者T分期有关,T分期越高mi R-137表达量越低(P<0.05);各胃癌细胞mi R-137表达量均低于正常胃黏膜细胞,且胃癌细胞侵袭力越强胃癌细胞mi R-137表达量越低(P<0.05);穿膜细胞数与mi R-137表达量之间呈明显负相关(r=-0.8881,P<0.05)。结论:胃癌组织mi R-137表达降低,且mi R-137表达量越低提示胃癌细胞侵袭能力越强。     

miR-519d在胰腺癌细胞中的表达及其作用

目的:探讨miR-519d在胰腺癌细胞中的表达及作用。方法:用qRT-PCR检测miR-519d在胰腺癌细胞系AsPC-1、BxPC-3、Capan-2、Panc-1及正常胰腺导管上皮细胞系HPDE6-C7中的表达。将Panc-1细胞分别转染miR-519d过表达质粒(miR-519d组)与阴性对照质粒(阴性对照组),以无处理的Panc-1细胞为空白对照组,用MTT法、Transwell实验、Western blot分别检测转染后细胞的增殖和侵袭能力、凋亡情况以及X连锁凋亡抑制蛋白(XIAP)的表达。结果:各胰腺癌细胞系中miR-519d相对表达量均明显低于正常胰腺导管上皮细胞系HPDE6-C7(均P0.05);与空白对照组比较,miR-519d组细胞增殖能力降低(培养72 h后明显降低)、凋亡率明显升高、侵袭能力明显减弱、XIAP蛋白表达量明显降低(均P0.05);阴性对照组各项指标与空白对照组差异均无统计学意义(均P0.05)。结论:miR-519d在胰腺癌细胞中表达下调,miR-519d表达下调有增强胰腺癌细胞增殖和侵袭能力、降低凋亡的作用,该作用可能与其调节XIAP蛋白的表达有关。     

microRNA-199b-5p在尤文肉瘤细胞系中的功能研究

目的探讨microRNA-199b-5p(mi R-199b-5p)在尤文肉瘤细胞系中的功能,分析其作用机制,以期为临床生物学治疗提供理论依据。方法取人尤文肉瘤细胞系A673、TC252,分别以mi R-199b-5p寡核苷酸片段(mimic)及其阴性对照(mimic control)转染,作为实验组及对照组。实时荧光定量PCR检测mi R-199b-5p m RNA相对表达量,并与MSCs比较;细胞计数试剂盒8法检测mi R-199b-5p对细胞增殖的影响;流式细胞术法检测对细胞周期及凋亡的影响。双荧光报告基因实验初步检测mi R-199b-5p可能作用的靶基因,Western blot验证靶基因。结果实时荧光定量PCR检测示,对照组A673细胞及TC252细胞中的mi R-199b-5p m RNA相对表达量与MSCs相比均显著下降(P0.05),与实验组对应细胞相比亦显著下降(P0.05)。与对照组对应细胞相比,实验组处于G1期细胞明显增多,S期细胞明显减少,比较差异均有统计学意义(P0.05);而两组G2/M期细胞无明显差异(P0.05)。实验组细胞凋亡率与对照组对应细胞相比显著增高(P0.05)。双荧光报告基因实验检测mi R-199b-5p可能作用的靶基因是细胞周期调节蛋白1(cyclin-L1,CCNL1)和c-Kit。Western blot检测显示,与对照组对应细胞相比,实验组CCNL1和c-Kit蛋白相对表达量明显下调,差异均有统计学意义(P0.05)。结论 mi R-199b-5p能抑制尤文肉瘤细胞增殖,阻滞细胞周期转换,促进细胞凋亡,其抑制作用是通过靶向CCNL1和c-Kit实现的。     

脊索瘤中microRNA的差异性表达及其RNA编辑

目的 :检测脊索瘤组织中micro RNA(mi RNA)的差异性表达情况,探讨其RNA编辑。方法 :使用RTq PCR(Real-time quantitative polymerase chain reaction)技术检测骶骨脊索瘤组织11种候选mi RNA的表达水平,将其与髓核组织中的表达水平进行比较,对表达异常的mi RNA前体(pri-mi RNAs)的DNA和c DNA序列进行对比,检测是否存在RNA编辑。使用蛋白印迹法(Western blot)检测脊索瘤组织中RNA编辑的关键酶RNA腺苷脱氨酶(adenosine deaminase acting on RNA,ADARs)的表达。构建ADAR的表达载体,同时构建ERBB2和HOXA1的3′-非翻译区报告载体并转染mi RNA模拟物和抑制物,将其和ADAR的表达载体共转染至人胚肾细胞293T(HEK293T细胞),用q RT-PCR检测mi RNA的表达水平,并通过荧光素酶报告基因活性分析法对已测得异常表达的mi RNA的靶基因ERBB2和HOXA1进行活性分析,检测ADAR与测得异常表达的mi RNA的靶基因的关系。结果:与髓核组织相比,脊索瘤组织中mi R-10a和mi R-125a的相对表达程度明显下调(P<0.05)。脊索瘤组织中mi R-10a和mi R-125a的前体c DNA序列中出现了腺苷酸向鸟苷酸(A-G)突变,而在髓核组织中mi R-10a和mi R-125a前体的c DNA序列中无此改变,mi R-10a和mi R-125a在成熟过程中出现了A-I RNA编辑。4组脊索瘤组织中有3组存在ADAR1过度表达,2组存在ADAR2过度表达。转染了mi RNA抑制物的HEK293T细胞中ADAR1表达出现上调,而mi R-10a和mi R-125a的表达出现下调,mi R-10a的靶基因ERBB2和mi R-125a的靶基因HOXA1的荧光素酶活性显著增高;相反,转染了mi RNA模拟物的HEK293T细胞中ADAR1表达出现下调,而mi R-10a和mi R-125a的表达出现上调,ERBB2和HOXA1的荧光素酶活性显著降低。结论:ADAR1的过度表达可能通过介导A-I RNA编辑影响mi R-10a和mi R-125a的成熟和表达,参与脊索瘤发生中的细胞异常增殖调控。     

miRNA-135a在肝癌组织中的表达及临床意义

目的 探讨mi RNA-135a(mi R-135a)在肝癌组织中的表达及其临床意义。方法 采用实时荧光定量PCR检测20例肝癌组织及其癌旁组织中mi R-135a的表达水平,并通过脂质体介导的方法将mi R-135a模拟物(mi R-135a mimics)转染肝癌细胞株Hep G2,采用实时荧光定量PCR测定转染后细胞中mi R-135a的表达水平;通过平板克隆实验和MTT法分别检测转染后细胞克隆形成率和存活率的变化,并对mi R-135a调控相关靶细胞的基因表达水平进行检测,观察mi R-135a在肝癌细胞维持正常功能中的作用。结果 通过对20例肝癌组织及其癌旁组织中mi R-135a的表达水平进行检测,结果 mi RNA-135a的表达在正常组织中相对更高,且两组之间存在显著性差异(P0.05);与阴性对照组比较,转染mi R-135a mimics后Hep G2细胞中mi R-135a表达水平显著提高(P0.05),而形成单克隆能力和细胞存活率均显著下降(P0.05),同时转染组细胞中与mi R-135a细胞调控相关靶基因FOS、PI3、Jak2、Stat3的m RNA表达量相较于NC组均显著降低(P0.05),表明mi R-135a表达提高后抑制细胞形成单克隆能力并降低存活率。结论 mi R-135a在正常组织和肝癌组织中差异表达,同时当mi R-135a表达提高时抑制肝癌细胞形成单克隆能力和降低细胞存活率,表明mi R-135a可能通过一些相关靶基因直接或间接调控Hep G2肝癌细胞的存活,在肝癌的发生过程中可能起到作用,mi R-135a可能成为临床治疗肝癌和预后的重要靶点。     

miR-150-5p抑制肝癌细胞的迁移和侵袭及其机制

目的:探讨mi R-150-5p在肝细胞癌(HCC)细胞迁移与侵袭中的作用及其调控机制。方法:用荧光定量PCR测定mi R-150-5p在正常肝细胞系L02及HCC细胞系Hep G2中的表达;将Hep G2细胞分成两组,分别转染mi R-150-5p(mi R-150-5p组)与随机序列(对照组),转染后,分别用细胞划痕实验、Transwell小室基质渗透实验检测细胞的迁移和侵袭能力,用Western blot检测细胞基质金属蛋白酶2(MMP2)和基质金属蛋白酶9(MMP9)的蛋白表达。结果:mi R-150-5p的表达量在Hep G2细胞系中明显降低,为L02细胞系的0.26倍(P0.01)。转染后,mi R-150-5p组的mi R-150-5p水平明显升高,为对照组的9.53倍(P0.001);mi R-150-5p组的细胞划痕愈合率明显低于对照组(54.63%vs.87.51%,P0.01),细胞侵袭数明显少于对照组(138个vs.452个,P0.01);MMP2与MMP9蛋白表达量均明显低于对照组(0.78 vs.1.75;0.82 vs.1.85,均P0.05)。结论:mi R-150-5p在HCC细胞中表达降低,升高mi R-150-5p的表达可抑制HCC细胞的迁移和侵袭,机制可能与其下调MMP2和MMP9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.     

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.     

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.