p38丝裂原活化蛋白激酶在肠缺血再灌注损伤大鼠炎性反应中的作用

目的探讨p38丝裂原活化蛋白激酶（p38MAPK）在肠缺血再灌注损伤大鼠炎性反应中的作用。方法健康成年雄性Wistar大鼠30只,随机分为3组（n=10）：假手术组（S组）、缺血再灌注组（I/R组）和p38MAPK抑制剂SB203580组（SB组）。采用夹闭肠系膜上动脉（SMA）的方法制备肠缺血再灌注损伤模型。I/R组和SB组夹闭SMA 1 h再灌注6 h,SB组缺血前30 min经股静脉注射p38MAPK特异性抑制剂SB203580 100μg/kg。于再灌注6 h时,处死大鼠,测定血浆肿瘤坏死因子-α（TNF-α）浓度、双胺氧化酶（DAO）活性及小肠组织TNF-α含量、p38MAPK、细胞间粘附分子-1（ICAM-1）表达水平,在光镜下观察小肠组织病理学,并进行小肠组织损伤程度评分。结果与S组比较,I/R组血浆TNF-α浓度、DAO活性及小肠组织p38MAPK、ICAM-1表达、TNF-α含量、小肠组织损伤程度评分升高,SB组血浆DAO活性、小肠组织ICAM-1表达、TNF-α含量及小肠组织损伤程度评分升高（P〈0.05）;与I/R组比较,SB组血浆TNF-α浓度、DAO活性及小肠组织p38MAPK、ICAM-1表达和TNF-α含量、小肠组织损伤程度评分降低（P〈0.05）。结论p38MAPK参与了肠缺血再灌注损伤大鼠炎性反应。     

高渗氯化钠羟乙基淀粉40注射液对大鼠脑缺血/再灌注损伤后凋亡细胞及对p38 MAPK和Ref-1表达的影响

目的 探讨高渗氯化钠羟乙基淀粉40注射液(hypertonic sodium chloride hydroxyethyl starch 40 injection,HSH)对大鼠脑缺血/再灌注(ischeamia/reperpusion,I/R)损伤的作用及其机制.方法 雄性SD大鼠90只,随机分为HSH组、缺血组(I/R)组和假手术对照(C)组,每组30只.I/R组和HSH组大鼠在凝断双侧椎动脉24 h后夹闭双侧颈总动脉,5 min后重新开放,制作全脑缺血模型.HSH组再灌注开始时静脉注射HSH 1.5 ml/kg,I/R组及C组分别静脉注射生理盐水6 mL/kg.各组在再灌注后6 h、12 h、24 h、48 h、72 h时取标本,制备脑组织病理切片,采用免疫组织化学染色方法测定p38蛋白和Ref-1蛋白的表达,TUNEL检测凋亡细胞数目.结果 与C组比较,I/R组凋亡细胞显著增多(P<0.05),I/R组在再灌注后各时点p38MAPK、Ref-1表达均显著增强(P<0.05),HSH组二者较C组表达增强但较I/R组表达显著减弱(P<0.05).结论 HSH对全脑I/R损伤有保护作用,其机制可能与其参与细胞信号转导减弱p38、Ref-1蛋白表达强度有关.     

牛磺酸对大鼠肝缺血再灌注后小肠损伤的保护作用

目的探讨牛磺酸对大鼠肝缺血再灌注(I/R)后小肠损伤的保护作用。方法将大鼠随机分成假手术组,肝I/R组,牛磺酸预处理+肝I/R组;采用阻断肝动脉、门静脉30min后再灌注的方法,制作肝I/R模型。各组于再灌注3,6,24h分别采血,测定二胺氧化酶(DAO)数值,检测小肠功能;同步切取小肠,测定肠道组织中的SOD及MDA含量,评价肠道自由基损伤程度;切片后行苏木素-伊红(HE)染色,观察病理形态学改变;原位末端标记法(TUNEL)测定细胞凋亡;免疫组化法测定caspase-3表达。结果与假手术组比较,肝I/R组SOD水平明显降低(P<0.05),MDA和DAO水平明显升高(P<0.05),小肠病理损伤严重,凋亡指数明显升高(P<0.05),caspase-3阳性率明显增加(P<0.05)。与I/R组同时间点比较,牛磺酸预处理+I/R组各项指标均明显改善(均P<0.05)。结论牛磺酸对肝I/R后小肠损伤具有保护作用。     

大鼠肠缺血再灌注对小肠屏障、吸收、通透和蠕动功能的影响

目的从不同角度探讨大鼠肠缺血再灌注对小肠屏障、吸收、通透和蠕动等功能的影响,为更深入地研究创伤后肠道损伤及其保护提供理论及诊治依据.方法42只Wistar大鼠随机分成健康对照组(C)、单纯肠系膜上动脉夹闭组(Ⅰ)、肠系膜上动脉夹闭再灌1h组(Ⅰ/R1h)、肠系膜上动脉夹闭再灌2h组(Ⅰ/R2h)和肠系膜上动脉夹闭再灌4h组(Ⅰ/R4h).动物活杀后取血和小肠组织,测定血浆和小肠组织二胺氧化酶(DAO),观察肠屏障功能的变化;测定血浆D-乳酸浓度以判断小肠通透性;测定血浆中D-木糖含量以作小肠吸收功能的诊断;肠道给予葡聚糖蓝来测定肠蠕动的长度.与此同时,还进行小肠组织脂质过氧化(MDA)的测定和普通小肠光镜检查.结果缺血再灌注后各组血浆DAO较C组显著升高(P＜0.05),而小肠组织DAO则在各组有不同程度降低,其中在Ⅰ/R 2h和Ⅰ/R 4h组降低显著.血浆和小肠组织DAO的变化呈显著的负相关(P＜0.05);缺血再灌注后小肠D-木糖的吸收呈显著升高(P＜0.05);缺血再灌注后各组D-乳酸的浓度有不同程度升高,其中Ⅰ/R1h和Ⅰ/R2h组升高显著(P＜0.05);给予葡聚糖蓝后各组小肠染色长度均显著较C组有增加(P＜0.05);小肠MDA含量在Ⅰ/R2h和Ⅰ/R4h组有升高,Ⅰ/R4h组较C组显著升高(P＜0.05).小肠组织HE染色光镜检查见小肠绒毛有较多嗜酸性白细胞,有少量淋巴细胞浸润,小肠绒毛出血.结论肠缺血再灌注后小肠的屏障、吸收、通透性及肠蠕动功能均发生不同程度的改变.     

肠缺血再灌注对小肠功能的影响

目的从不同角度探讨大鼠肠缺血再灌注对小肠屏障、吸收、通透和传输等功能的影响,为更深入地研究肠道损伤及其保护提供防治依据.方法以Wistar大鼠肠缺血再灌注(I/R)作模型,将动物随机分为健康对照(C)、肠系膜上动脉夹闭1h(I)、夹闭后再灌1h(R 1h)、2h(R 2h)和4h(R 4h)共5个组.分别测血或小肠组织的二胺氧化酶(DAO)、D-乳酸、D-木糖、肠传输、脂质过氧化物(MDA)和髓过氧化物酶(MPO),并作小肠普通光镜检查.结果R 1h和R 4h组的血浆DAO显著升高(P<0.05),小肠DAO各组有不同程度的降低,R 2h组降低显著,血浆和小肠DAO的变化呈负相关(r=-0.648,P<0.05).缺血和再灌注后各时相点血D-乳酸浓度升高,其中R 1h和R 2h升高显著(P<0.05).缺血再灌后肠道D-木糖的吸收增加,小肠的传输显著加快.结论肠缺血和再灌注后小肠的屏障、吸收、通透和传输功能均显示不同程度的改变.     

小肠缺血再灌注后氧自由基和肝超微结构改变及凋亡相关基因的表达

目的:研究大鼠小肠缺血再灌注(I/R)后血中氧自由基的改变以及肝组织中bax、bcl-2、p53的表达及肝组织超微结构的变化,以探讨小肠I/R后肝绢织的损伤及其机制.方法:建立小肠I/R模型,分对照组、I/R后0 min、30 min、1 h、2 h、1 d、3 d及7 d共8组,于各时点检测血中一氧化氮(NO)和超氧化物岐化酶(SOD)的浓度,用免疫组织化学SP法观察肝组织中bax、bcl-2及p53的表达情况,透射电镜观察肝组织细胞超微结构变化.结果:大鼠小肠I/R后NO浓度在冉灌注0 min时升高,至冉灌注2 h时明显降低.其后又持续升高,至冉灌注7 d时达高峰.SOD的浓度变化则相反.再灌注0 min时肝组织中bax、bcl-2及p53阳性细胞率增高,再灌注30 min时阳性细胞率升高更为明显,但bcl-2表达高于bax,二者差别显著(P＜0.01).再灌注2 h时3种基因均有所降低,其后又开始升高,至再灌注7 d时阳性细胞率达高峰.bax表达明显高于bcl-2.二者差别显著(P＜0.01).透射电镜显示肝组织细胞超微结构损伤改变.结论:血中NO和SOD浓度的变化及肝组织中超微结构的改变表明,小肠I/R可引起肝组织细胞凋亡和损伤;而I/R后bax、bcl-2及p53阳性细胞在肝组织中的表达明显改变,可能与引起细胞凋亡和损伤有关.     

p38 MAPK在沙土鼠前脑缺血再灌注损伤及缺血预处理中的作用

目的 研究p38 MAPK在沙土鼠前脑缺血再灌注损伤及缺血预处理中的作用。方法 雄性蒙古沙土鼠384只，体重50-80 g，随机分为6组，每组64只。假手术组（SH组）：仅游离双侧颈总动脉但不阻断;缺血再灌注组（I／R组）：夹闭双侧颈总动脉，前脑缺血5min后恢复灌注;缺血预处理组（IP组）：前脑缺血3 min后恢复灌注，24 h后再行前脑缺血5 min;P组：于前脑缺血前20 min侧脑室内注射0．8μg p38 MAPK特异性激动剂P79350;SB组：于前脑缺血前20 min侧脑室内注射0．4μg p38 MAPK特异性抑制剂SB202190;溶剂对照组（VE组）：于前脑缺血前20min侧脑室内注射1％二甲基亚砜4μl。各组于再灌注15min、2h、4h、6h分别取8只沙土鼠，测定海马CA1区p-p38 MAPK的表达，再灌注1、3、5、7d分别取8只沙土鼠，采用开阔法观察行为学，然后测定海马CA1区存活神经元计数、凋亡神经元计数及p-p38 MAPK、HSP27、Bcl-2、Bax的表达。结果 I／R组再灌注期p-p38 MAPK表达上调，IP组及SB组再灌注各时点p-p38 MAPK表达水平低于I／R组，P组再灌注各时点高于I／R组、IP组及SB组（P〈0．05）;IP组、SB组较I／R组及vE组沙土鼠探索活动减少，CA1区再灌注期凋亡神经元数减少，HSP27、Bax表达下调，存活神经元数增加，Bcl-2表达上调（P〈0．05）;P组再灌注1 d探索活动增加，再灌注各时点p38 MAPK及HSP27表达均较I／R组上调（P〈0．05）。结论 沙土鼠脑缺血再灌注损伤及神经元凋亡与p38 MAPK的激活有关;缺血预处理可通过抑制p38 MAPK的激活，下调HSP27及Bax的表达、上调Bcl-2的表达。     

白介素6对人髓核细胞凋亡的影响

[目的]研究炎症因子IL-6对人髓核细胞凋亡的影响及可能机制。[方法]培养人髓核细胞,将细胞随即分为4组:IL-6刺激组;IL-6+P38MAPK阻断组;IL-6+JNK/SAPK阻断组及对照组。然后用AnnexinV/PI染色流式细胞仪和TUNEL法检测髓核细胞凋亡情况,免疫荧光检测P-P38MAPK和P-JNK/SAPK的表达及定位;West-ern印迹法检测P38MAPK、JNK/SAPK及各自活化形式,即P-P38MAPK和P-JNK/SAPK的表达。[结果]流式细胞仪和TUNEL法检测凋亡结果中,IL-6刺激组相对于对照组及各阻断组有着较高的凋亡细胞密度(P0.01);免疫荧光结果显示IL-6刺激组P-P38MAPK和P-JNK/SAPK在细胞质和细胞核均有表达,各阻断组在细胞质和细胞核可见少量表达,与IL-6刺激组差异有显著统计学意义(P0.01),对照组仅见极少量表达;Western印迹法结果显示P38MAPK,JNK/SAPK在各组髓核细胞内均有表达,但无活化形式,IL-6刺激组可见P-P38MAPK,P-JNK/SAPK表达,但相应阻断组无表达。[结论]外源性IL-6可通过P38MAPK和P-JNK/SAPK途径导致人髓核细胞凋亡。     

高渗氯化钠羟乙基淀粉40注射液对大鼠脑缺血／再灌注损伤后凋亡细胞及对p38MAPK和Ref-1表达的影响

目的探讨高渗氯化钠羟乙基淀粉40注射液（hypertonic sodium chloride hydroxyethvl starch 40 injection,HSH）对大鼠脑缺血／再灌注（ischeamia／reperpusion,I／R）损伤的作用及其机制。方法雄性SD大鼠90只,随机分为HSH组、缺血组（I／R）组和假手术对照（C）组,每组30只。I／R组和HSH组大鼠在凝断双侧椎动脉24h后夹闭双侧颈总动脉,5min后重新开放,制作全脑缺血模型。HSH组再灌注开始时静脉注射HSH1．5ml／kg,I／R组及c组分别静脉注射生理盐水6ml／kg。各组在再灌注后6h、12h、24h、48h、72h时取标本,制备脑组织病理切片,采用免疫组织化学染色方法测定p38蛋白和Ref-1蛋白的表达,TUNEL检测凋亡细胞数目。结果与C组比较,I／R组凋亡细胞显著增多（P＜0．05）,I／R组在再灌注后各时点p38MAPK、ReH表达均显著增强（P＜0．05）,HSH组二者较C组表达增强但较I／R组表达显著减弱（P＜0．05）。结论HSH对全脑L／R损伤有保护作用,其机制可能与其参与细胞信号转导减弱p38、Ref-1蛋白表达强度有关。     

NSC23766对糖尿病大鼠局灶性脑缺血再灌注损伤的影响

目的 评价NSC23766对糖尿病大鼠局灶性脑缺血再灌注损伤的影响.方法 健康成年雄性SD大鼠,2～3月龄,体重250～300 g,采用腹腔注射链脲佐菌素60mg/kg的方法制备糖尿病模型.取糖尿病模型制备成功的大鼠51只,采用随机数字表法,将其随机分为3组(n=17):假手术组(S组)、缺血再灌注组(I/R组)和Racl特异性抑制剂NSC23766组(N组).I/R组和N组采用线栓法制备局灶性脑缺血再灌注损伤模型,N组于缺血前15 min经侧脑室注射NSC23766 50μg,S组与I/R组给予等容量生理盐水.于再灌注24 h时进行神经功能缺陷评分,然后处死大鼠,取脑组织,测定脑梗死体积,HE及Nissl染色,光镜下观察病理学结果,并测定细胞凋亡指数和p38丝裂原活化蛋白激酶 (p38MAPK)磷酸化水平.结果 与S组比较,I/R组和N组神经功能缺陷评分和细胞凋亡指数升高,脑梗死体积增大,p38MAPK磷酸化水平上调(P＜0.05);与I/R组比较,N组神经功能缺陷评分和细胞凋亡指数降低,脑梗死体积缩小,p38MAPK磷酸化水平下调(P＜0.05).结论 NSC23766可减轻糖尿病大鼠局灶性脑缺血再灌注损伤.     

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.