肾病综合征药物反应差异与相关细胞色素P450酶遗传机制的研究进展

为揭示肾病综合征在治疗过程中个体间药物反应差异的机制，阐明CYP450酶遗传变异与药物代谢的基本规律和个体差异的作用，本文综述了几种CYP450同工酶的基因结构、多态性、底物及诱导等方面的研究进展。     

细胞色素P450 3A4和3A5对磷酸二酯酶5抑制剂（PDE5Is）-西地那非，优地那非，伐地那非3种药物代谢的影响

细胞色素P450 3A5（CYP3A5）基因多态性在细胞色素P4503A（CYP3A）底物代谢上的作用目前尚不清楚，Ku HY等人进行了一项相关研究，分析了CYP3A4和CYP3A5两种异构体对PDE，抑制剂-西地那非，优地那非，伐地那非3种药物代谢的差异。研究者采用重组的CYP3A和15个以CYP3A5基因表型为主的人肝微粒体进行体外研究，     

麻醉药物代谢酶CYP450酶系基因组学研究进展

遗传多态性是造成个体对药物反应差异的重要因素之一,其中CYP450酶系的基因多态性可能导致种族间及个体间对同一底物代谢能力的不同.现就镇静安定药、吸入麻醉药、局麻药、镇痛药的药物效应与CYP450基因多态性的相关性进行综述,为临床个体化给药,实现个体优化治疗提供新思路.     

CYP3A5在肝移植术后他克莫司个体化治疗中的意义

目的总结CYP3A5在肝移植术后他克莫司个体化治疗中的意义。方法复习、分析近年来有关肝移植患者CYP3A5基因多态性对他克莫司药代动力学影响的文献。结果他克莫司可以有效预防肝移植的排斥反应。药代动力学中狭窄的有效药物浓度范围和个体差异使其很难确定针对所有患者的固定剂量,药物代谢酶和转运子的基因多态性影响着他克莫司的血药浓度。CYP3A5基因分型影响着肝移植受体的他克莫司需要量。结论 CYP3A5基因分型可能为优化肝移植患者的免疫抑制治疗提供帮助。     

麻醉药物代谢酶CYP450酶系基因组学研究进展

遗传多态性是造成个体对药物反应差异的重要因素之一，其中CYP450酶系的基因多态性可能导致种族间及个体间对同一底物代谢能力的不同。现就镇静安定药、吸入麻醉药、局麻药、镇痛药的药物效应与CY450基因多态性的相关性进行综述，为临床个体化给药，实现个体优化治疗提供新思路。     

雌激素代谢酶CYP17、CYP19单核苷多态性与乳腺癌易感性的相关性分析

目的 初步探讨雌激素代谢酶CYP17和CYP19单核苷多态性与乳腺癌易感性的相关性.方法 采用聚合酶链反应-限制性片段长度多态性及短串联重复多态性方法,检测213例乳腺癌患者和430例正常对照CYP17、CYP19单核苷多态性分布.结果 乳腺癌患者雌激素代谢酶CYP17 A2/A2基因型频率为6.7%,高于对照组的2.4%(P＜0.05),CYP17变异等位基因A2病例组的频率为16.2%,亦明显高于对照组的10.6%(P＜0.05);乳腺癌患者雌激素代谢酶CYP19(TTTA)10等位基因病例组的频率为12.4%,对照组为8.2%,差异有统计学意义(P＜0.05).结论 CYP17单核苷多态性与乳腺癌易感性相关,A2/A2基因型增加乳腺癌风险;CYP19单核苷多态性与乳腺癌易感性亦相关,CYP19(TTTA)10等位基因变异升高与乳腺癌易感性高度相关.     

肾移植受者CYP3A5基因多态性对术后他克莫司药物代谢的影响

目的 研究肾移植受者细胞色素P450 3A(CMP3A)酶系中的CYP3A5基因多态性对术后他克莫司(Tac)药物代谢的影响,并探讨测定CYP3A5基因型的方法 .方法 选取97例肾移植术后常规使用Tac+吗替麦考酚酯+泼尼松三联免疫抑制方案的受者.用焦磷酸测序法测定受者CYP3A5基因型;用均相酶扩大免疫分析法(EMIT)测定受者全血Tac浓度谷值(C0);比较不同基因型的受者肾移植术后第7天、第14天、1个月、3个月和6个月时的Tac C0,与Tac校正剂量的比值(Tac G0/Tac校正剂量).结果 焦磷酸测序法能够快速准确的测定肾移植受者CYP3A5基因型;97例肾移植受者CYP3A5基因型分别为:CYP3A5+1/*1型17例(17.5%),CYP3A5* 1/*3型35例(36.1%),CYP3A5*3/*3型45例(46.4%).CYP3A5*1/*1型和CYP3A5*1/*3型受者肾移植术后Tac G0/Tac校正剂量均显著低于CYP3A5*3/*3型受者.结论 肾移植受者CYP3A5基因型对Tac药物代谢具有显著的影响.采用焦磷酸法测定肾移植受者CYP3A5基因多态性,有助于确定不同个体移植术后理想的Tac起始剂量,实现Tac个体化用药.     

MDR-1和CYP3A基因多态性在肝肾移植中的应用

MDR-1和CYP3A分别编码P-糖蛋白和药物代谢酶P4503A,两者对于免疫抑制剂在体内达到有效血药浓度水平具有重要的作用。本文介绍了这两个基因的多态性在药物代谢方面的作用,以及其多态性与环孢霉素A和普乐可复的关系。     

MDR-1和CYP3A基因多态性在肝肾移植中的应用

MDR-1和CYP3A分别编码P-糖蛋白和药物代谢酶P4503A，两者对于免疫抑制剂在体内达到有效血药浓度水平具有重要的作用。本文介绍了这两个基因的多态性在药物代谢方面的作用，以及其多态性与环孢霉素A和普乐可复的关系。     

肾移植术后稳定期受者应用他克莫司的剂量及血药浓度个体差异的研究

他克莫司(Tac)的应用使肾移植受者临床疗效发牛了根本改善,但其较窄的治疗指数和不同个体间的高度差异一直困扰着临床医师.我们从药物基因组学角度分析了肾移植受者细胞色素酶P450-3A5(CYP3A5)和多药耐药基因((MI)R1)的基因多态性,并紧密结合肾移植术后稳定期受者的临床特点,采用多元线性同归分析方法对119例受者进行了研究,以探讨肾移植术后稳定期受者Tac应用剂量及血药浓度个体差异的原因.     

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.     

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.     

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.