酸性成纤维细胞生长因子基因转染改善缺血心肌血流灌注的研究

目的　探讨酸性成纤维细胞生长因子 (aFGF)基因重组腺病毒 (Ad .aFGF)转染改善缺血心肌血流灌注的作用。方法　小型猪左冠回旋支 (Lcx)放置Ameroid环后 4周 ,注射Ad .aFGF(n =7)、空病毒 (Ad .Null,n =6 )、磷酸盐缓冲液 (PBS ,n =6 )于Lcx供血区域 ,每头 10点 ,每点 1× 10 9pfu或 10 0 μl的PBS。 4周后 ,单光子计算机断层扫描 (SPECT )和心脏超声分别检测局部血流灌注和心功能。注射点心肌Ⅷ因子免疫组织化学染色观察血管新生。结果　SPECT显示Ad .aFGF组心肌核素摄取评分 ( 76 .1± 2 .9)显著高于Ad .Null组 ( 6 4.6± 3 .0 ,P <0 .0 1)和PBS组( 6 5 .4± 3 .9,P <0 .0 1) ;超声显示Ad .FGF组节段性室壁收缩期增厚率 ( 34.1± 1.8) %显著高于Ad .Null组 [( 2 4.2± 2 .3) % ,P <0 .0 1]和PBS组 [( 2 3 .7± 2 .2 ) % ,P <0 .0 1] ;免疫组织化学显示Ad .aFGF组心肌中血管密度 [( 32 .8± 1.9)个 /每高倍视野 (HPF) ]显著高于Ad .Null组 [( 18.2±1.5 )个 /HPF ,P <0 .0 1]和PBS组 [( 17.3± 1.7)个 /HPF ,P <0 .0 1]。结论　Ad .aFGF转染慢性缺血心肌可增加血流灌注 ,改善心功能。     

猪慢性心肌缺血模型的建立

目的建立一个良好的慢性心肌缺血模型.方法 12只中华实验小型猪,开胸将Ameroid慢性缩窄环置于左冠状动脉前降支的近端,经4～6周后行冠状动脉造影判断狭窄的情况.结果 12只猪中8只手术顺利完成,饲养4～6周后,行冠状动脉造影显示前降支均见明显的狭窄,狭窄程度为90%～100%;4只死亡.结论应用Ameroid慢性缩窄环置于前降支的近端可建立良好的慢性心肌缺血动物模型.     

腺病毒携带肝细胞生长因子基因不同途径转染对大鼠急性缺血心肌的影响

目的探讨腺病毒携带肝细胞生长因子基因（Ad-HGF）不同途径转染对大鼠缺血心肌的影响。方法将75只大鼠随机分为心肌内注射Ad，HGF组、注射携带绿色荧光蛋白（Ad-GFP）组、注射生理盐水空白对照组，心室腔注射Ad-HGF组、注射Ad-GFP组，各组分别于第3、7、14、21、28天各处死3只检查腺病毒的分布情况及进行血管计数。结果心肌内和心室腔注射Ad-HGF组第14、21、28天可见新生血管生成数量显著增加，与对照组相比差异有统计学意义（P〈0．05）。心肌内注射Ad-GFP组术后3d心脏绿色荧光最强，14d消失，心腔内注射Ad-GFP组术后3d心脏可见到范围较小的微弱绿色荧光，7d消失。结论Ad-HGF可明显促进大鼠缺血心肌微小血管生成，心肌内直接注射途径仍优于心腔内给药。     

携带Ad.ANG的骨髓基质细胞移植于缺血心肌的实验研究

目的　利用编码血管生长素基因的腺病毒 (Ad .ANG)转染骨髓基质细胞 (BMSCs) ,并移植于缺血心肌 ,研究其对心功能的保护作用。方法　Ad .ANG体外转染BMSCs后 ,通过ELISA方法检测ANG的表达和分泌情况 ;将转染Ad .ANG的BMSCs移植于同基因背景Lewis大鼠梗死心肌 ,通过EF、左室舒张末期容积等超声指标研究其对心功能的保护作用 ,另外通过免疫组化、电镜研究细胞存活、分化和血管新生情况。结果　Ad .ANG转染BMSCs后 ,在培养上清中有大量ANG出现 ,4～ 7d时表达达到高峰 ,15d后仍可检测到蛋白表达。移植于缺血心肌 4周后 ,实验组在心功能改善方面明显好于单纯细胞移植组 (P <0 0 5 )、Ad .ANG治疗组 (P <0 0 1)和空白对照组 (P <0 0 1) ,在促血管新生方面 ,实验组也明显优于以上 3组。结论　转染Ad .ANG后的BMSCs可获得很高的表达水平 ,移植于缺血心肌后 ,在改善心功能和促进血管新生方面明显优于单纯细胞移植组和基因治疗组。     

血管内皮生长因子定向转染诱导缺血心肌血管生成的研究

目的观察血管内皮生长因子（VEGF）质粒直接心肌注射对兔急性心肌缺血后侧支循环形成的影响。方法建立兔左冠状动脉结扎的急性心肌缺血模型，取缺血边缘区以先期构建的真核表达质粒pcDNA3／VEGF165和真核载体pcDNA3的DNA分别多点心肌注射，给药后2、4周取材分别行逆转录-聚合酶链反应（RT-PCR）和蛋白浓度分析、苏木素-伊红（HE）染色、VEGF染色。结果治疗组VEGF165 mRNA含量较对照组明显增多；蛋白浓度分析转染后VEGF165显著增多，高峰出现于实验后2周；治疗组缺血心肌新生血管数目明显多于对照组。结论VEGF165外源性基因能在转染心肌细胞后成功表达，促进了缺血心肌血管新生和侧支循环形成。     

骨髓间充质干细胞移植重建大鼠缺血心肌的实验研究

目的　探讨大鼠骨髓间充质干细胞 (MSCs)移植于缺血心肌后的增殖分化情况和对缺血心肌细胞的修复重建能力及心功能改善情况。　方法　实验组为将体外培养SD大鼠的MSCs经溴氮胞苷 (BrdU)标记后显微注射于结扎冠状动脉后的大鼠缺血心肌内 ,并以无血清培养基注射动物为对照组。 4周后观察移植细胞的分化情况 ,并通过超声多普勒、心肌核素显像、免疫组化和新生血管形成情况来检测心功能变化。　结果　实验组MSCs移植 4周后 ,在缺血心肌区内可发现不同分化阶段的心肌样细胞。超声检查发现实验组的左室射血分数 (LVEF)的改善明显好于对照组 (P <0 0 5 ) ;SPECT显示实验组心肌核素摄取显著高于对照组 (P <0 0 1) ;在促新生血管形成方面 ,实验组也明显好于对照组(P <0 0 5 )。　结论　骨髓间充质干细胞移植于缺血心肌后可重建缺血心肌 ,增加心肌灌注 ,显著改善心功能。     

吗啡预先给药对急性心肌缺血大鼠心肌P物质和降钙素基因相关肽的影响

目的观察吗啡预先给药对急性心肌缺血大鼠心肌组织缺血区和非缺血区P物质(SP)和降钙素基因相关肽(CGRP)表达的影响。方法健康成年雄性SD大鼠18只,体重270～300 g,随机分为3组(n=6),假手术组(S组)、单纯冠状动脉结扎组(I组)、吗啡干预冠状动脉结扎组(M组)。S组大鼠开胸后在冠状动脉左前降支下穿线不结扎;I组大鼠开胸后结扎冠状动脉左前降支;M组大鼠经尾静脉注射吗啡1．25 mg·kg-1,15 min后结扎冠状动脉左前降支。各组在手术后计时3 h。采用免疫组化、酶联免疫和反转录-聚合酶链反应法从蛋白和基因水平观察各组大鼠缺血区和非缺血区心肌SP和CGRP的表达。结果I组大鼠缺血区心肌SP／SP mRNA和CGRP／β-CGRP mRNA的水平较S组升高(P<0．05),M组低于I组(P<0．05),但仍高于S组(P<0．05);非缺血区各组的变化趋势类同缺血区,但各扎闭冠状动脉组SP／SP mRNA和CGRP／β-CGRP mRNA的水平均低于相应组缺血区的水平(P <0．05)。结论吗啡预先给药可降低急性心肌缺血大鼠心肌组织SP和CGRP的表达。     

高机械指数三维超声联合微泡改善缺血心肌再灌注

目的探讨经胸三维高机械指数诊断超声联合微泡增强溶栓效果、改善缺血心肌微灌注的可行性。方法将15只冠状动脉左前降支血栓栓塞模型猪分为实验组(n=8)和对照组(n=7)。实验组给予组织型纤溶酶原激活剂(tPA)静脉注射和脂质微泡静脉输注,同时对心前区予高机械指数三维超声辐照30min;对照组仅予tPA静脉注射及微泡静脉输注。观察治疗90min后阻塞冠状动脉再通率、治疗前及治疗90min后缺血区室壁增厚率、危险心肌面积、治疗前及治疗30、60、90min后心电图抬高ST段回落情况。结果治疗90min后,两组冠状动脉再通率差异无统计学意义;实验组室壁增厚率显著高于治疗前,而对照组治疗前后室壁增厚率差异无统计学意义。实验组治疗30、60、90min后,心电图抬高ST段均较治疗前显著回落,而对照组仅在治疗90min后有回落。实验组治疗90min后危险心肌面积较治疗前显著降低,对照组无明显变化;实验组冠状动脉造影无再通者(n=5)治疗90min后造影所示缺血心肌面积较治疗前显著降低。结论冠状动脉造影未显示血管再通时,经胸三维高机械指数超声联合微泡可显著改善猪阻塞区心肌微循环灌注。     

肺癌中5型腺病毒受体表达与腺病毒感染效率的关系

目的 观察肺癌细胞中5型腺病毒(Ad5)及改良Ad5(Ad5F35)受体CAR和CD46的表达,探讨它们与Ad5、Ad5F35型腺病毒感染效率的关系.方法 采用流式细胞术检测人肺癌细胞株及10例原代培养肺癌细胞中CAR和CD46的表达水平.以带有绿色荧光蛋白(GFP)标记的Ad5和Ad5F35型腺病毒按10和50的感染强度(MOI)感染上述细胞,48 h后通过流式细胞术检测GFP表达阳性细胞百分率.结果 所检测的4株肺癌细胞和10例原代肺癌细胞中CD46的表达水平均明显高于CAR.Ad5-GFP(MOI=50)感染48 h后,A549、Z793、QG56和NCI-H520细胞GFP阳性表达率分别为39%、37%、45%和4%;同样浓度的Ad5F35-GFP感染48 h后,A549、Z793、QG56和NCI-H520细胞GFP阳性率分别为78%、75%、75%和54%.10例原代肺癌细胞中Ad5F35-GFP感染后GFP阳性细胞比例也明显高于Ad5-GFP.结论 Ad5及Ad5F35型腺病毒的基因转移效率与细胞中CAR和CD46的表达水平密切相关.肺癌细胞中CD46的表达水平普遍高于CAR,而Ad5F35对肺癌细胞的感染能力明显优于Ad5.     

腺病毒介导的LacZ基因在大鼠坐骨神经的表达

目的 :观察腺病毒介导的LacZ基因在大鼠坐骨神经雪旺细胞 (Schwanncells ,SCs)的表达。方法 :大鼠坐骨神经内直接注射报告基因LacZ重组腺病毒 (Ad LacZ) ,X gal组织化学染色检测LacZ基因的表达 ,采用LEICAM 5 5 0型图像分析仪对坐骨神经切片X gal染色强弱进行定量评价。结果 :将滴度为 1× 10 8PFU /ml的Ad LacZ病毒液 10 μl注入坐骨神经 2d后即可检测到LacZ的表达 ,7～ 14d表达显著增加 (与 2d组比较P <0 .0 1) ,7d组与 14d组表达量无显著差异 (P >0 .0 5 ) ,2 8d时SCs蓝染又减弱 (与 7d组和 14d组比较P <0 .0 1)。注射生理盐水的对照组X gal染色阴性。结论 :腺病毒介导的LacZ基因可转入活体动物坐骨神经内并高效表达 ,表明腺病毒介导神经营养因子等基因治疗有促进周围神经损伤再生的作用。     

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.