缬沙坦对糖尿病肾病大鼠肾间质纤维化的作用

目的 探讨缬沙坦在防治糖尿病肾病(DN)大鼠肾间质纤维化( RIF)中的作用及其机制.方法 54只大鼠随机被分为对照组(C组)、DN模型组(D组)和缬沙坦治疗组(T组).D组和T组大鼠分别给予链脲菌素( STZ)一次性腹腔注射建立糖尿病大鼠模型.造模后T组给予缬沙坦混悬液40 mg· kg-1·d-1,分别于实验第4周、第8周和第12周末测血糖、血浆白蛋白、Scr、尿蛋白.Masson染色观察RIF面积.免疫组化法检查肾组织缺氧诱导因子1α( HIF-1α)、金属蛋白酶1组织抑制剂(TIMP-1)、基质金属蛋白酶9(MMP-9)的表达.实时荧光定量PCR测定其mRNA表达.结果 与C组比较,D组及T组大鼠24 h尿蛋白量、Scr均显著升高,肾组织RIF面积、HIF-1α、TIMP-1蛋白及mRNA表达均显著增加,血清白蛋白及肾组织中MMP-9蛋白及其mRNA表达均明显减少,差异均有统计学意义(均P＜0.05).与同时间点D组比较,T组在实验第8周末、第12周末24h尿蛋白、Scr均显著降低,肾组织中RIF面积、HIF-1α、TIMP-1蛋白及其mRNA表达均显著减少,血清白蛋白及肾组织中MMP-9及其mRNA表达均显著增多,差异均有统计学意义(均P＜0.05).结论 缬沙坦可能通过下调HIF-1α、TIMP-1表达,上调MMP-9表达,延缓肾间质纤维化.     

芡实对糖尿病肾病大鼠肾组织MMP-9、TIMP-1及Collagen Ⅳ表达的影响

目的:探讨芡实对糖尿病肾病大鼠肾组织MMP-9、TIMP-1及CollagenⅣ表达的影响。方法:健康雄性Wistar大鼠65只,随机选取10只为正常对照组(N组);其余一次性腹腔注射链脲佐菌素(STZ)制作DN模型,造模成功后,随机分为DN组、芡实低、中、高剂量组及氯沙坦钾组,均采用灌胃给药,N组和DN组给予等体积蒸馏水。12周后检测大鼠生化指标;HE、Masson、PAS染色观察肾脏病理变化;免疫组化法测定MMP-9、TIMP-1及CollagenⅣ在肾组织表达情况;采用实时荧光定量PCR技术检测肾组织中MMP-9、TIMP-1及CollagenⅣ基因的表达。结果:实验12周末,与N组比较,DN组大鼠肾小球肥大,细胞外基质积聚,血糖、24 h尿蛋白定量、血尿素氮(BUN)、肌酐(Scr)、尿白蛋白排泄率(UAER)、尿蛋白/尿肌酐(Up/Ucr)比值显著升高(P0.05),肾组织MMP-9蛋白和mRNA表达降低(P0.05),TIMP-1、CollagenⅣ蛋白和mRNA表达升高(P0.05);与DN组比较,EM组、EH组及LP组大鼠病理改变减轻,24 h尿蛋白定量、Scr、BUN、UAER、Up/Ucr显著降低(P0.05),肾组织MMP-9蛋白和mRNA表达显著升高(P0.05),TIMP-1、CollagenⅣ蛋白和mRNA表达显著减少(P0.05)。结论:芡实可能通过调节DN大鼠肾脏MMP-9、TIMP-1的表达,减少细胞外基质积聚,从而减轻肾小球硬化,减少蛋白尿,保护肾功能,延缓DN病变的进展。     

基质金属蛋白酶9、3和金属蛋白酶组织抑制物1在原发性膜性肾病肾小球内的表达及意义

目的探讨基质金属蛋白酶9（MMP-9）、基质金属蛋白酶3（MMP-3）和金属蛋白酶组织抑制物1（TIMP-1）在原发性膜性肾病（IMN）患者肾小球内的表达变化及其与蛋白尿、Scr的关系。方法用免疫组织化学技术分别检测44例IMN患者（IMN组）与6例正常对照者（对照组）肾小球内MMP-9、MMP-3和TIMP-1的表达。结果MMP-9及MMP-3在对照组正常肾组织的肾小管上皮细胞、肾间质和肾小球足细胞有少量表达；在IMN组肾小球足细胞、系膜细胞、肾小球基底膜及肾小管上皮细胞有表达。IMN组肾小球内MMP-9及MMP-3的表达均较对照组显著增强（P〈0．05）。TIMP-1在对照组正常肾组织的肾小管上皮细胞有少量表达，肾小球内无表达；在IMN组肾小球足细胞、肾小管上皮细胞有表达。IMN组肾小球内TIMP-1的表达较对照组显著增强（P〈0．01）。IMN组24h尿蛋白定量显著高于对照组（P〈0．01）。Ⅱ期MN组肾小球MMP-9／TIMP-1及MMP-3／TIMP-1比值较Ⅰ期MN组明显下降（P〈0．01）。IMN组肾小球内MMP-9的表达与Scr呈负相关（r=-0．02，P〈0．05）；TIMP-1的表达与Scr呈正相关（r=0．34，P〈0．05）。结论MMP-9与TIMP-1从正反两方面影响IMN患者肾功能的改变。MMP-9、MMP-3的异常表达与IMN患者蛋白尿之间可能相关；IMN患者肾小球MMP／TIMP比值失衡可能与IMN患者肾小球基底膜增厚相关。     

肿瘤坏死因子α对人腹膜间皮细胞基质金属蛋白酶及其组织抑制物表达的影响

目的 观察肿瘤坏死因子α（TNF-α）对人腹膜间皮细胞(HPMC) 基质金属蛋白酶（MMP）2、MMP-9及其组织抑制物（TIMP）2、TIMP-1 mRNA和Ⅰ型胶原表达的影响，同时观察TNF-α、TGF-β、IL-1单独或协同作用对HPMC的MMP-9活性的影响。 方法 采用半定量RT-PCR法测定细胞MMP-2、MMP-9、TIMP-2及TIMP-1 mRNA 的表达。采用Biotrak MMP-9 活性检测系统来精确定量测定MMP-9活性及MMP-9原的含量。ELISA法检测Ⅰ型胶原蛋白的表达。 结果 TNF-α(1~10 μg/L)分别刺激HPMC 4、16、24及48 h后， HPMC的MMP-9 mRNA表达显著上调，为基础的2.3～4.9倍（P ＜ 0.05），呈时间依赖性。TNF-α（1 μg/L）作用48 h后显著下调TIMP-1、TIMP-2 mRNA 表达，为基础的77.2％、61.3％（P ＜ 0.05），而MMP-2 mRNA表达没有显著变化。TNF-α+TGF-β１ （1~10 μg/L）、 TNF-α+TGF-β1+IL-1(1~10 μg/L)和TNF-α(5~10 μg/L)刺激HPMC 24 h后，促其分泌MMP-9 的作用最为明显。同时，TNF-α明显上调Ⅰ型胶原蛋白表达（P ＜ 0.05）。 结论 TNF-α 明显上调HPMC的MMP-9 mRNA的表达和MMP-9 的活性；联合其他细胞因子后促MMP-9分泌的作用更明显。TNF-α单独或协同其他因子在腹膜纤维化的过程中可能发挥了重要作用。     

参地补肾胶囊对肾小球硬化大鼠MMP-9、TIMP-1及其受体mRNA表达的影响

目的:观察参地补肾胶囊对肾小球硬化大鼠基质金属蛋白酶(MMP-9)、基质金属蛋白酶抑制物(TIMP-1)及其受体mRNA表达的影响,探讨其抗肾小球硬化的机制。方法:采用单侧肾脏切除同时尾静脉注射阿霉素的方法建立肾小球硬化大鼠模型,SD大鼠随机分为空白对照组、模型组、参地补肾胶囊组、贝那普利组、苏黄泄浊丸组,检测血肌酐(Scr)、尿素氮(BUN)、血浆蛋白(Alb);免疫组化法检测MMP-9、TIMP-1的表达,计算MMP-9/TIMP-1比值,RT-PCR检测受体TIMP-1mRNA的表达水平。结果:与模型组比较,参地补肾胶囊组能抑制TIMP-1及其受体mRNA的表达(P<0.01),上调MMP-9表达(P<0.01),提高MMP-9/TIMP-1的比值。结论:参地补肾胶囊可抑制TIMP-1及其受体mRNA的表达,改善肾脏病理形态,进而延缓肾小球硬化进展。     

创伤弧菌脓毒症大鼠肝脏基质金属蛋白酶及其抑制基因的表达

目的观察创伤弧菌脓毒症大鼠肝脏组织基质金属蛋白酶（MMP-2、MMP-9）及其抑制基因（TIMP-2、RECK）表达水平的变化,探讨它们在创伤弧菌脓毒症中的作用。方法清洁级Sprague-Dawley雄性大鼠60只,随机分为6组,每组10只。第1组为健康对照组,第2—6组为创伤弧菌脓毒症模型组。观察大鼠行为学改变,提取各组大鼠肝脏组织总RNA,半定量RT-PCR法检测MMP-2、MMP-9以及TIMP-2、RECK基因mRNA水平表达的变化。结果染菌4h后,大鼠出现呼吸急促,皮温升高,下肢肿胀,且症状进行性加重;染菌12h后,大鼠出现紫绀、间断抽搐等症状。染菌2、6和9h后,大鼠肝脏组织中MMP-2及MMP-9基因mRNA水平表达明显上调,TIMP-2和RECK表达水平下调。结论MMP-2和MMP-9表达上调,以及TIMP-2和RECK表达水平下调提示它们可能参与了创伤弧菌脓毒症的病理生理过程。     

狼疮肾炎与基质金属蛋白酶-9表达的相关分析

目的探讨狼疮肾炎（LN）与基质金属蛋白酶-9（MMP-9）及金属蛋白酶组织抑制因子-1（TIMP-1）表达的相互关系。方法采用逆转录-聚合酶链反应（RT-PCR）方法检测17例LN患者和22例无明显肾损害（24h尿蛋白定量〈500mg）的系统性红斑狼疮（SLE）患者外周血单个核细胞MMP-9mRNA和TIMP-1mRNA的表达水平。结果17例LN患者MMP-9／β-actin与TIMP-1／β-actin比值分别为（0．94±0．16）和（0．78±0．49）,与22例无明显肾损害（24h尿蛋白定量〈500mg）的SLE患者比较,其MMP-9 mRNA表达水平显著升高,具有统计学差异（P〈0．01）,但TIMP-1 mRNA表达水平无明显差异（P〉0．05）。结论LN患者MMP-9的异常表达可能与其肾脏病理损伤有关。     

阿仑膦酸钠对长期应用糖皮质激素大鼠股骨头骨组织MMP/TIMP系统的影响

目的观察阿仑膦酸钠对长期应用皮质激素大鼠骨组织中基质金属蛋白酶-2（MMP-2）、MMP-9及其特异性抑制因子基质金属蛋白酶组织抑制剂-1（TIMP-1）和TIMP-2mRNA表达的影响,探讨阿仑膦酸钠预防激素性股骨头坏死的效果及其作用机制。方法健康SD大鼠30只,雌雄各半,随机分为激素组、阿仑膦酸钠组和空白对照组,每组10只。激素组和阿仑膦酸钠组肌内注射醋酸泼尼松龙12.5mg/kg,每周2次,阿仑膦酸钠组同时给予阿仑膦酸钠5mg/kg灌胃,每周1次;对照组只给予相同体积生理盐水肌注。4周后取左侧股骨头骨组织石蜡包埋,HE染色,鉴定骨质疏松和股骨头坏死情况;取右侧股骨头骨组织提取总RNA,采用逆转录聚合酶链反应（RT-PCR）技术检测MMP-2、MMP-9、TIMP-1和TIMP-2的mRNA表达水平。结果 MMP-2在激素组、阿仑膦酸钠组、对照组中的表达分别为0.15±0.04、0.13±0.07、0.09±0.03,MMP-9在三组中的表达分别为0.13±0.03,0.09±0.02和0.08±0.02;TIMP-1在三组中的表达分别为0.07±0.02,0.13±0.4和0.18±0.04;TIMP-2在三组中的表达分别为0.45±0.15,0.63±0.10和0.69±0.19。激素组与对照组比较,MMP-2、MMP-9mRNA表达增高,TIMP-1、TIMP-2mRNA表达降低,差异有统计学意义（P〈0.05）。阿仑膦酸钠组与对照组比较,仅MMP-2显著性差异。阿仑膦酸钠组与激素组比较,MMP-2、MMP-9mRNA表达降低,TIMP-1、TIMP-2mRNA表达增加,差异有统计学意义（P〈0.05）。结论醋酸泼尼松龙上调大鼠骨组织中MMP-2、MMP-9mRNA的表达,下调TIMP-1、TIMP-2水平,使MMPs/TIMPs比值升高。阿仑膦酸钠可以拮抗皮质激素对MMPs/TIMPs系统的调控。     

补肾排毒合剂对单侧输尿管梗阻大鼠肾间质MMP-9与TIMP-1基因表达的影响

目的：研究单侧输尿管梗阻（unilateral ureteral obstruction，UUO）后大鼠肾间质MMP-9、TIMP-1基因的表达变化，探讨补肾排毒合剂对肾间质纤维化的保护作用。方法：采用UUO诱导肾间质纤维化的动物模型，将大鼠随机分为假手术组（Sham组）、模型组（UUO组）和补肾排毒合剂治疗组（REM组），用RT—PCR技术检测肾组织在术后3、10、20、30d MMP-9、TIMP-1的基因表达。结果：UUO组TIMP-1 mRNA的表达明显高于Sham组（P〈0．01），REM组TIMP-1 mRNA表达均明显低于UUO组（P〈0、01）。MMP-9 mRNA在UUO术后明显升高，第10天达到高峰，继之下降。REM组10d后下降幅度较小，在20、30d时间点高于UUO组（P〈0，01）。结论：补肾排毒合剂影响MMP-9／TIMP-1的基因表达，从而促进了ECM的降解过程，延缓肾间质纤维化的进展。     

霉酚酸酯对糖尿病大鼠肾脏基质金属蛋白酶9、转化生长因子β1表达的影响

目的 探讨霉酚酸酯（MMF）对糖尿病（DM）大鼠肾脏的保护作用及其机制。 方法 将实验动物分为正常对照组、DM组及MMF治疗组。MMF组给予MMF(15 mg/kg,口服,1次/d) 治疗。8 周后检测各组大鼠尿蛋白量（24 h）、内生肌酐清除率（Ccr）、血糖;HE染色观察肾脏病理改变;免疫组化及RT-PCR法检测肾组织中基质金属蛋白酶9（MMP-9）、转化生长因子β1（TGF-β1）的表达。 结果 DM组大鼠血糖[（22.18±3.36） mmol/L比（6.40±0.87）mmol/L]、尿蛋白量（24 h）[（26.80±0.82） mg比（6.64±1.42） mg]、Ccr[（0.220±0.380） ml/min比（0.098±0.015） ml/min]显著高于对照组（P ＜ 0.05）。MMF组的尿蛋白量（24 h）[（16.17±1.15） mg]、Ccr[（0.220±0.380） ml/min比（0.207±0.377） ml/min]均显著低于DM组（P ＜ 0.05）。与DM组比较,MMF组肾小球肿大、系膜细胞增生显著减轻。肾组织中MMP-9在对照组表达较多,主要在肾小球系膜细胞胞质内及肾小管上皮细胞,DM组表达较弱,MMF组介于两组之间,组间差异均有统计学意义（P < 0.05）。TGF-β1在正常对照组大鼠肾组织有少量表达,在DM组表达较强,在MMF组介于两组之间,组间差异亦均有统计学意义（P < 0.05）。 结论 MMF可降低DM大鼠尿蛋白排泄、Ccr,减轻早期肾小球肥大,此作用可能与MMF上调肾组织中MMP-9表达、下调TGF-β1的表达、减少系膜外基质的沉积有关。     

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.