hIGF-I基因增强Mosaicplasty技术重建膝负重区大面积骨软骨复合缺损实验研究

目的研究hIGF-I基因增强组织工程提高Mosaicplasty修复大面积骨软骨缺损的修复质量，改善骨软骨的整合。 方法制造山羊膝关节股骨髁大面积骨软骨缺损模型，使用自制Mosaicplasty器械，植入2 mm直径骨软骨柱镶嵌充填缺损，以hIGF-I基因转染的骨髓基质干细胞复合可注射藻酸钙凝胶填充残余缺损。同时设立未转染hIGF-I基因的骨髓基质干细胞组、Mosaicplasty组和对照组。术后4 w、8 w、16 w处死动物，行大体观察、光镜、电镜观察，磁共振检查比较修复效果。 结果骨软骨缺损在16 w时IGF-I基因增强Mosaicplasty组移植物固定牢固，关节面平滑，移植物间界限消失，新生软骨组织类似于正常软骨，4~16 w修复效果逐渐改善，优于其他各组。光镜观察见移植的骨软骨生长良好，与新生软骨组织紧密相连，新生的软骨细胞排列规整，细胞外基质分布均一。对照组无明显修复。MRI观察类似大体观察结果。 结论使用转染hIGF-I基因的骨髓基质干细胞复合可注射藻酸钙凝胶可促进Mosaicplasty后骨软骨的整合，改善其修复效果。     

BMSCs复合PHBV原位修复兔鼻中隔软骨缺损的实验研究

目的探索BMSCs复合PHBV原位修复兔鼻中隔软骨缺损的可行性。方法建立兔鼻中隔软骨缺损模型。将36只健康新西兰大白兔随机分成3组。实验组:软骨缺损处植入BMSCs-PHBV复合物进行修复;对照组:软骨缺损处植入单纯PHBV支架材料进行修复。空白组:单纯取出鼻中隔软骨,不予修复。分别于16、24周取材,行大体观察及组织学检测。结果大体观察显示,实验组新生软骨样组织将鼻中隔软骨缺损区填充修复,与周围软骨组织未见明显分界;对照组新生软骨薄,与周围组织分界明显;空白组鼻中隔软骨缺损区未生成软骨组织,缺损部位及其周围正常软骨组织被纤维结缔组织充填覆盖。组织学检测显示,实验组构建的软骨组织结构致密,基质及Ⅱ型胶原显色程度均明显强于对照组构建的软骨。结论 BMSCs-PHBV复合物能有效修复兔鼻中隔软骨缺损。     

兔自体松质骨颗粒修复关节软骨损伤

目的研究兔自体松质骨颗粒在膝关节软骨损伤处移植后能够诱导软骨组织生成、促进关节软骨损伤修复的现象。方法 12只新西兰大白兔麻醉后在兔的右侧膝关节股骨远端内、外侧髁负重区用电钻分别造成直径、深度均为3 mm的骨软骨缺损创面,取同侧髂骨松质骨,制成直径约为1 mm松质骨颗粒植入股骨内侧髁软骨缺损处,作为实验组,外侧髁软骨缺损不做处理作为对照组。术后12周进行膝关节大体观察、病理切片染色,评估关节软骨损伤的修复情况。结果兔膝关节实验组软骨缺损处被新生软骨填充,软骨面光滑,组织切片染色显示有关节软骨形成。对照组缺损创面仍然凹陷,仅在缺损边缘有少量软骨生长。结论兔自体松质骨颗粒在膝关节软骨损伤处能够诱导软骨生成,促进关节软骨的修复,是一种良好的关节软骨损伤修复方法。     

自体骨软骨移植与含富集骨髓干细胞松质骨移植修复兔关节软骨缺损

目的:评价自体骨软骨移植与含富集骨髓干细胞松质骨镶嵌移植两种方法修复全层关节软骨缺损的生物学特征和效果。方法:采用新西兰大白兔制作左右后肢全层软骨缺损模型,分别进行自体骨软骨镶嵌移植、含富集骨髓干细胞松质骨镶嵌移植修复,对照组不作任何修复,每组12只。术后第4、8、12周处死动物取材,分别进行膝关节活动度测定、大体观察、光镜观察与电镜观察。结果:移植实验组在第12周时均能以类透明软骨组织修复缺损,对照组为纤维肉芽组织。形态学检查表明,两种方法均能以类透明软骨组织覆盖缺损,骨软骨移植组无明显免疫排斥现象,随着时间延长,修复高度逐渐增加。骨软骨移植组同含富集骨髓干细胞松质骨镶嵌移植组效果无显著差别。结论:骨软骨移植、含富集骨髓干细胞松质骨镶嵌移植两种方法均能以类透明软骨组织修复全层关节软骨缺损,含富集骨髓干细胞松质骨镶嵌移植更适用于较大面积软骨缺损的修复。     

骨软骨镶嵌成形术修复骨软骨复合缺损的比较研究

目的观察采用骨软骨镶嵌成形术（Mosaicplasty）修复膝关节中等和大面积骨软骨复合缺损的效果,为临床应用提供理论依据。方法24只成年山羊随机分成3组（n=8）。中等面积缺损组在股骨内髁制造直径6mm缺损,植入直径2mm骨软骨柱修复;大面积缺损组于股骨内髁制造9mm直径缺损,以直径3mm骨软骨柱修复;对照组于股骨内髁制造直径6mm缺损后不修复。自股骨髁间窝和滑车沟两侧非负重区用自制Mosaicplasty器械钻取骨软骨柱,推出器嵌入缺损处镶嵌填满。术后4、8、16及24周处死动物,取修复骨软骨组织行大体观察、HE及甲苯胺蓝染色。术后24周,取大面积缺损组和对照组膝关节摄X线片,观察骨软骨缺损修复情况,并分别取修复组织及正常软骨组织行蛋白聚糖（glycosaminogly cans,GAG）含量测定。结果中等面积缺损组术后4周,移植的骨软骨柱与基底部骨床结合牢固;8-24周软骨层之间以及与正常软骨间界限仍清晰。大面积缺损组术后4周,移植的骨软骨柱与基底骨床结合牢固,部分骨软骨柱被压入骨床内;8-24周压陷程度加重,与股骨髁相对关节面的部分软骨被磨损。对照组24周缺损仍无明显修复迹象,与股骨髁相对关节面的软骨磨损剥脱。组织学观察结果类似大体观察,术后24周中等及大面积缺损组软骨柱间均有缝隙存在,大面积缺损组毗邻软骨细胞稀疏肥大。术后24周,X线片可见大面积缺损组软骨下骨愈合良好,而对照组仍可见骨质缺损,与股骨髁相对关节面的软骨局部骨质硬化;软骨GAG含量测定显示正常软骨和大面积缺损组修复组织间差异无统计学意义（P〉0.05）;前两者与对照组修复组织比较,差异均有统计学差异（P〈0.05）。结论Mosaicplasty可修复中等面积骨软骨复合缺损,但无法有效修复大面积缺损,效果有待改进。     

自体骨软骨镶嵌移植成形术

自体骨软骨镶嵌移植成形术(Mosaicplasty)是近年来国外新兴的治疗骨软骨缺损的手术方法，在经过数年的研究与随访之后，其优势已逐渐显现出来．并被大众所接受。骨软骨缺损为软骨下骨与软骨面的复合型缺损，Mosaicplasty可一期同时重建坚强支撑的软骨下骨和正常结构的软骨。     

自体骨软骨镶嵌移植修复猪膝关节骨软骨缺损

目的: 探讨猪自体骨软骨镶嵌移植治疗股骨负重区骨软骨复合缺损的优缺点。方法: 采用德国Arthrex公司OATS软骨移植器械, 进行长枫杂交仔猪同关节非负重区骨软骨移植修复负重区骨软骨缺损。结果: 12周后发现骨软骨柱移植后存活良好, 移植软骨中心区无明显凹陷及退变, 甚至稍有凸起, 质地同正常软骨; 与周围正常软骨界限仍清晰, 交界区软骨整合差, 有明显裂隙存在; 骨软骨供区有明显凹陷, 为白色组织充填, 质软, 周围可见正常软骨退变。结论: 自体骨软骨镶嵌移植具有移植软骨固定可靠、软骨细胞存活率高等优点, 但也有交界区整合差, 为纤维软骨修复等缺点。     

股骨头内支撑器/重组人骨形态发生蛋白/自体松质骨对犬股骨头坏死软骨下骨缺损的修复

目的探索应用新材料、新方法修复股骨头坏死骨缺损重建股骨头力学性能的新方法。方法活门法(trapdoor)建立犬股骨头骨缺损模型。通过活门A组植入股骨头内支撑器/重组人骨形态发生蛋白(rhBMP)2/自体松质骨;B组植入重组人骨形态发生蛋白(rhBMP)2/自体松质骨;C组植入自体松质骨。通过组织学、影象学、生物力学观察评价对股骨头骨缺损的修复以及重建股骨头力学性能的效果。结果各组均未出现关节脱位、关节间隙正常。A组缺损区修复,无关节软骨塌陷,内支撑器与周围骨组织融合;B组,骨缺损区修复,但骨密度低于周围骨组织;C组,仅缺损区周围少量低密度骨形成。A组组织学无软骨塌陷,内支撑器周围新生骨组织包绕,与周围骨组织融合;B组2例软骨塌陷(1.2mm,1.5mm),活门区软骨色泽近与正常,缺损区由新生骨组织填充;C组,活门区软骨塌陷(1.8～5.2mm),色泽苍白,质软易碎,骨缺损区边缘少量新生骨组织,骨小梁纤细稀疏。A组抗压强度为(289.46±23.05)MPa,B组抗压强度为(128.34±6.23)MPa,C组抗压强度(119.54±64.75)MPa,A明显强于B、C两组,且差异有统计学意义(P<0.05)。结论应用股骨头内支撑器/rhBMP2/自体松质骨修复股骨头软骨下骨缺损可以加快修复速度,并且恢复重建股骨头力学强度,有效的防止股骨头关节软骨的塌陷。     

可注射性藻酸钙凝胶修复整合兔膝关节骨软骨缺损实验研究

目的: 使用骨髓基质干细胞 (BMSCs)、藻酸钙及两种生长因子, 修复兔股骨内髁负重区骨软骨缺损, 寻找合适的关节骨软骨缺损修复方法。方法: 将藻酸钙、体外培养扩增的自体BMSCs及IGF I TGF β复合材料注射于兔膝关节股骨内髁负重区上的骨软骨缺损。结果: BMSCs在藻酸钙中能分化为软骨细胞和成骨细胞, 材料无毒副作用; 关节骨软骨缺损后注入BMSCs 藻酸钙 IGF I TGF β复合体, 各期修复较对照组均有统计学意义 (P<0. 05)。结论: 藻酸钙能为BMSCs提供良好三维生长环境并能使之保持正常形态; BMSCs 藻酸钙 IGF I TGF β复合体能用于关节骨软骨急性缺损修复, 形成正常透明软骨样结构, 软骨下骨修复良好。     

脱细胞骨软骨支架复合自体骨髓间充质干细胞修复羊骨软骨缺损的研究

目的探讨脱细胞骨软骨支架接种自体骨髓间充质干细胞(BMSCs)修复羊骨软骨缺损效果,探索骨软骨缺损新的修复方式。方法制备直径为8mm骨软骨脱细胞支架,培养羊BMSCs,接种于骨软骨支架,制备羊负重区骨软骨缺损模型,分空白、空白支架及细胞支架复合物3组,每组4只羊,3个月后处死动物取标本行大体及组织学检测。结果修复羊负重区骨软骨缺损模型实验结果显示细胞支架复合修复组骨软骨有较好修复,空白支架组软骨下骨基本修复、软骨侧无明显修复,空白对照组未见明显修复,缺损边缘软骨退变。结论含骨软骨连接结构的脱细胞骨软骨支架接种种子细胞能较好的修复羊负重区骨软骨缺损。     

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.