新疆维吾尔族人群雄激素受体基因CAG重复多态性与良性前列腺增生的关系

目的　初步探讨雄激素受体 (AR)基因CAG重复多态性与良性前列腺增生 (BPH)的关系。　方法　收集 80例维吾尔族BPH患者和 4 0例健康者外周血标本 ,应用PCR和直接测序法行AR基因CAG重复长度测定。分析评价CAG重复长度与BPH的关系。　结果　BPH组CAG重复次数范围 13～ 30 ,平均 2 2 .78。对照组CAG重复次数范围 14～ 2 9,平均 2 2 .38。两组比较差异无显著性意义 (P >0 .0 5 )。CAG重复长度 <2 2和≥ 2 2比较 ,其OR值为 1.0 6 (95 %CI 0 .4 6～ 2 .4 8,P >0 .0 5 )。CAG重复长度与BPH患者年龄 (γ =- 0 .0 6 ,P >0 .0 5 )、国际前列腺症状评分 (IPSS) (γ =0 .11,P >0 .0 5 )无相关性 ,而与前列腺的体积相关 (γ =- 0 .2 6 ,P <0 .0 5 )。在BPH患者 ,前列腺体积随着CAG重复次数的增加而减小 ,差异有显著性意义 (趋势检验P <0 .0 5 ) ,CAG重复长度≤ 2 0与≥ 2 5相比 ,前列腺体积差异有显著性意义 (P =0 .0 5 )。　结论　AR基因CAG重复长度与BPH腺体的增长有关。     

前列腺癌与雄激素受体基因(CAG)n重复多态性的关系

目的　探讨前列腺癌 (PC)与雄激素受体 (AR)基因 (CAG)n重复多态性的关系。　方法　应用DNA双链循环测序方法对 34例PC组织与癌旁正常组织、2例PC患者外周血白细胞内的AR基因 (CAG)n重复数进行测定。　结果　同一PC患者的癌组织与癌旁正常组织 (CAG)n重复数相同 ;36例患者癌组织AR基因 (CAG)n呈重复多态性 ,平均 2 0 .0 6 ,显著低于正常组织 ,差别有显著性意义 (P <0 .0 5 ) ;不同分化程度的癌组织 (CAG)n重复数差别无显著性意义 (P >0 .0 5 )。　结论　AR基因 (CAG)n重复数改变的体细胞突变在PC癌细胞中罕见 ,该重复数的减少可能与PC发病相关     

雄激素受体基因CAG多态性与迟发性性腺功能减退症的相关性研究

目的:研究雄激素受体基因(AR)重复序列(CAG)n多态性与迟发性性腺功能减退症(LOH)的关系,探讨LOH的发病机制。方法:共调查1 000例40～70岁中老年男性,其中19例迟发性性腺功能减退症患者,随机抽取127例正常健康中老年男性,测定甘油三酯(TG)、空腹血糖(FBG)、血清总睾酮(TT)、游离睾酮(fT),测量身高、体重、腰围(WC)、血压,并采用DNA测序方法进行AR基因外显子1氨基端转录调节区(CAG)n重复序列长度测定,比较两组各指标之间的差异。结果:(CAG)n重复次数为15～32(23.05±2.95)。正常健康中老年男性的体重指数(BMI)、FBG较LOH患者显著下降(P<0.01),而TG、TT及fT较LOH患者显著升高(P<0.01)。正常健康中老年男性AR基因(CAG)n重复数为22.54±3.06;LOH患者AR基因(CAG)n重复数为23.23±2.24;LOH患者(CAG)n重复数略高于正常健康人群,但两者比较无统计学意义(P=0.946)。(CAG)n重复长度显示:长组(n≥22)AR基因(CAG)n在LOH组和正常健康中老年男性组的频率分别为73.68%和48.82%(P<0.05)。相关分析显示:TT、fT与(CAG)n重复序列无明显相关性(r=0.04和r=0.025,P>0.05)。结论:LOH男性AR基因(CAG)n重复序列呈现多态性,长(CAG)n重复多态可能是LOH发病的遗传因素,但仍需进一步扩大样本量证实。     

CYP1A1与GSTM1基因多态性与前列腺癌易感性的关系

目的　探讨CYP1A1、GSTM1基因多态性与前列腺癌遗传易感性的关系。　方法　采用寡核苷酸芯片对 83例前列腺癌患者和 115例正常对照的中国汉族人群基因组DNA进行CYP1A1、GSTM1基因多态性分析。　结果　GSTM1基因缺失型前列腺癌组占 5 7.8% ,对照组 4 1.7% ,差异有显著性意义 ( χ2 =4 .99,P =0 .0 2 5 ) ,GSTM1null基因型使患前列腺癌的危险度增加 1.9倍 ( 95 %CI=1.10～ 1.34)。GSTM1基因缺失型前列腺癌患者的平均年龄 [( 6 8.1± 8.3)岁 ]低于GSTM1未缺失的患者[( 71.9± 7.4 )岁 ,P =0 .0 31]。前列腺癌组CYP1A1基因的两个多态位点m1、m2基因型频率和等位基因的频率与对照组相比差异无显著性意义 (P >0 .0 5 )。　结论　中国汉族人群GSTM1基因多态性与前列腺癌的发生相关 ,可能是增加前列腺癌危险和发病年龄早的因素之一。CYP1A1基因m1和m2的基因多态与中国汉族人群前列腺癌的发生无相关性     

前列腺癌发生风险与CYP3A5基因多态性的关系

目的 探讨CYP3A5基因多态性与前列腺癌发生风险和病理特点的关系。方法 采用限制性片段多态性分析法对356例前列腺癌患者和306个男性对照中CYP3A5基因第3内含子多态性进行了研究。结果 在前列腺癌和对照组之间CYP3A5基因型分布差异无显著性(P=0．063)，但两组间CYP3A5*1等位基因的分布差异存在显著性(P=0．025)；与携带CYP3A5*3*3基因型者相比，携带CYP3A5*1等位基因的男性患前列腺癌的风险降低了30％(P=0．026)。在不同分期和分级的前列腺癌患者之间CYP3A5基因型分布差异无显著性(P=0．904和0．986)。结论 CYP3A5基因中的CYP3A5*1等位基因可能与前列腺癌的患病风险降低有关。     

中国汉族男性CYP17基因多态性与前列腺癌发生危险性的关系

目的　探讨CYP1 7基因多态性与前列腺癌发生危险性的关系。　方法　提取 1 2 5例前列腺癌患者和 1 5 8例对照组的血DNA标本 ,设计引物通过PCR技术扩增出包括基因多态位点的片段 ,用限制性内切酶MspA1Ⅰ进行酶切 ,产物在 2 %琼脂糖凝胶上电泳 ,确定出CYP1 7基因的 3种基因型 ,即A1 /A1、A1 /A2、A2 /A2 ,并经测序证实。　结果　基因型A1 /A2、A2 /A2频数与A1 /A1基因型进行比较 ,A1 /A2和A2 /A2在前列腺癌中的频数与对照组相比 ,其OR值分别为 1 .1 9和 1 .2 8,P值分别为 0 .5 7和 0 .4 5 ;但年龄 >6 9岁的病例中 ,其OR值分别为 3.97和 3.2 1 ,P值分别为 0 .0 0 7和 0 .0 2 3;对照组的血fPSA、tPSA水平 3组间差异无显著性意义。　结论　A1 /A2、A2 /A2基因型未增加汉族人群前列腺癌发生的危险性 ,基因型间血PSA水平差异无显著性支持这一观点。年龄 >6 9岁的人群中 ,A1 /A2、A2 /A2基因型显著增加前列腺癌发生的危险性 ,提示CYP1 7基因可能与老年男性前列腺癌发生危险性之间有密切关系     

雄激素受体基因CAG多态性对男性激素避孕有效性影响的研究

目的：分析应用肌注十一酸睾酮酯（TU）进行激素避孕的男性志愿者中起反应者与不起反应者雄激素受体（AR）基因（CAG）n微卫星多态性，并探讨该多态性对激素避孕效果的影响。方法：29例TU不起反应者和34例起反应者分别作为试验组和对照组，应用PCR和DNA测序技术对两组外周血标本进行CAG重复数测定，分析该微卫星多态性对激素避孕效果的影响。结果：试验组和对照组CAG重复数的均数分别为23．62和22．97，均数比较差异无显著性（P〉0．05）。短组CAG（n≤22）在试验组和对照组的分布分别为51．7％、50．0％；长组CAG（n〉22）在试验组和对照组分布分别为48．3％、50．0％，长短组分布相同。CAG重复数与精子密度之间未见相关性。在FSH浓度〉0．2IU／L组中，CAG重复数〉22的受试者达到无精子症的机会是其他受试者的1．5倍。结论：受试者AR基因（CAG）n重复数呈多态性，但不反应组与反应组之间不具有显著性差异，AR基因CAG重复数或其他因素与男性激素避孕效果之间的关系有待进一步探讨。     

雄激素受体及前列腺特异性抗原基因多态性与前列腺癌易感性

雄激素受体(AR)基因CAG重复多态性与前列腺特异性抗原(PSA)基因ARE I G/A多态性及其交互作用影响了前列腺癌的发病风险及血清PSA水平的变化,本文就近年来AR基因与PSA基因多态性和前列腺癌易感性间的关系作一综述,并着重讨论了AR基因与PSA基因多态性交互作用对前列腺癌发病风险的影响。     

雄激素受体基因CAG多态性对男性激素避孕有效性影响的研究

目的:分析应用肌注十一酸睾酮酯(TU)进行激素避孕的男性志愿者中起反应者与不起反应者雄激素受体(AR)基因(CAG)n微卫星多态性,并探讨该多态性对激素避孕效果的影响。方法:29例TU不起反应者和34例起反应者分别作为试验组和对照组,应用PCR和DNA测序技术对两组外周血标本进行CAG重复数测定,分析该微卫星多态性对激素避孕效果的影响。结果:试验组和对照组CAG重复数的均数分别为23.62和22.97,均数比较差异无显著性(P>0.05)。短组CAG(n≤22)在试验组和对照组的分布分别为51.7%、50.0%;长组CAG(n>22)在试验组和对照组分布分别为48.3%、50.0%,长短组分布相同。CAG重复数与精子密度之间未见相关性。在FSH浓度>0.2IU/L组中,CAG重复数>22的受试者达到无精子症的机会是其他受试者的1.5倍。结论:受试者AR基因(CAG)n重复数呈多态性,但不反应组与反应组之间不具有显著性差异,AR基因CAG重复数或其他因素与男性激素避孕效果之间的关系有待进一步探讨。     

前列腺癌患者雄激素受体N端AF1区的突变研究

目的　探讨雄激素受体 (AR)N端转录活化功能区 (AF1)突变与进展的关系。　方法采用PCR SSCP(单链构象多态性 ) DNA双链循环测序法对 2 7例前列腺癌 (PC)石蜡切片组织的ARN端AF1区突变进行检测 ,用DNA测序法确定PC组织AR基因外显子A中的CAG重复数目[(CAG)n]。　结果　在ARN端的AF1区证实了 2种错义突变 (Gly142Val和Asp2 2 1His) ,均存在于低分化的PC组织。 2例突变AR基因外显子A的 (CAG)n均为 17。　结论　在国人PC组织ARN端AF1区发现了 2种新的AR基因突变型 ,突变AR的 (CAG)n重复数目均低于平均水平 ,提示AR突变可能与PC进展有关     

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.