胆固醇结石病人肝脏脂质代谢异常的分子生物学研究

目的:研究导致胆石病人胆汁胆固醇过饱和的肝脏胆固醇和胆汁酸代谢途径中的分子生物学改变。方法:收集22例胆石病人和13例无胆石病的对照病人肝脏活检组织、胆囊胆汁和血浆。采用实时定量PCR检测肝脏基因表达,采用Western印迹法测定蛋白含量。结果:胆石病人较对照组ABCG5/ABCG8和LXRα基因的mRNA表达水平分别增加51%、59%和102%。肝脏SRBI的mRNA和蛋白含量均增加。结论:胆石病人ABCG5/ABCG8基因表达上调,可能与LXRα表达增加促进相关,这些异常是导致胆汁胆固醇过饱和的原因。此外,胆汁中过多的胆固醇可能来源于经肝脏高密度脂蛋白受体SRBI的摄取,而不是由于肝脏合成和酯化的异常。     

从胆石成因研究谈胆石病预防的新策略

胆囊胆固醇结石病发病率有不断增加趋势。在胆石病发病机制中,胆汁胆固醇过饱和是胆石形成的必要条件。近年来的研究显示,胆石病患者肝肠循环脂质代谢异常是导致胆汁胆固醇过饱和的分子生物学基础：包括肝脏高密度脂蛋白受体增加胆固醇的摄入、胆小管侧膜胆固醇转运蛋白增加向胆汁中分泌以及经小肠摄人体内的胆固醇增加。大量实验证据表明,对肝肠循环脂质代谢异常进行有效干预,通过降低肝脏胆固醇负荷及其分泌,抑制小肠胆固醇摄取等多个环节,维持胆汁胆固醇的平衡,有望成为预防胆石形成的一系列新的措施。     

胆囊黏膜ABCG5和ABCG8基因在胆固醇结石病中的作用

目的探讨ABCG5和ABCG8基因在胆囊黏膜中的表达与胆固醇结石病的关系。方法采集28例胆囊胆固醇结石病患者和10例无胆石对照的胆囊黏膜和胆汁、胆石。测定胆汁胆固醇、胆汁酸和磷脂含量;Real-time PCR测定胆囊黏膜中ABCG5和ABCG8的表达量。结果胆石组中胆固醇摩尔百分比和饱和指数均较对照组显著升高(P<0.01);ABCG5和ABCG8的表达呈显著正相关(r=0.55,P<0.01),胆石组中ABCG5和ABCG8的mRNA表达分别是对照组的2.8倍(P<0.01)和1.9倍(P<0.05)。结论胆固醇结石病患者的胆囊黏膜ABCG5和ABCG8基因表达增高,限制了胆囊上皮对胆固醇的吸收,使胆汁过饱和状态得以维持。     

胆色素结石肝细胞胆小管侧膜转运蛋白mRNA表达的实验研究

目的:探讨肝细胞胆小管侧膜转运蛋白表达与胆色素结石形成间的相关性及其可能的作用机制.方法:豚鼠45只随机分为对照组(CON)、成石组(PS),分别给予正常饲料、胆色素结石致石饮食,饲养8周建立胆囊胆色素结石模型,检测并比较各组胆结石成石率、肝细胞胆小管侧膜转运蛋白mRNA表达.结果:成石组成石率为68.24％,与对照组相比,成石组豚鼠的肝细胞胆小管侧膜Abcb11(t=6.885,P＜0.01)和Abcc2 (t=6.794,P＜0.01)的mRNA的表达水平都比较低.而各组中胆固醇转运蛋白Abcg5及Abcg8在mRNA水平表达未见有明显差异.结论:胆色素结石与肝细胞胆小管侧膜转运蛋白的表达之间具有一定的相关性.肝细胞胆小管侧膜转运蛋白表达改变影响肝细胞分泌功能,导致胆汁易成石,在促进胆色素结石的形成中发挥一定的作用.     

胆囊黏膜ABCG5和ABCG8与胆囊胆固醇息肉关系的研究

目的:研究胆囊黏膜ABCG5和ABCG8的基因表达与胆囊胆固醇息肉发病的关系.方法:收集63例因胆囊疾患而行腹腔镜胆囊切除术患者的胆石、胆汁及部分胆囊黏膜组织,其中胆囊胆固醇息肉32例,胆囊胆固醇结石18例,对照13例(胆囊腺瘤6例,非胆固醇胆囊结石7例),分别测定胆石胆固醇含量,胆汁胆固醇、胆汁酸、磷脂的浓度,实时定量PCR检测胆囊黏膜ABCG5和ABCG8的mRNA表达.结果:胆固醇息肉组胆汁胆固醇饱和指数较对照组明显增高(P<0.01),结石组胆囊黏膜ABCG5和ABCG8的表达量较息肉组和对照组显著增高,息肉组和对照组ABCG5和ABCG8的表达量差异无统计学意义(P>0.05).结论:胆囊黏膜ABCG5/ABCG8 mRNA的相对低水平表达,可能是导致胆囊胆固醇息肉发病的重要因素之一.     

胆囊结石病人小肠胆固醇吸收相关基因表达的初步研究

目的 该研究通过分析胆石病人小肠胆固醇吸收相关基因的表达情况探讨小肠胆固醇吸收的遗传凶素在胆石病发生中的作用.方法 研究包括10例胆囊结石病人和7例无胆石症的对照.实时定量PCR法测定近段空肠黏膜胆固醇吸收相关基因mRNA的表达量.结果 胆石组小肠胆固醇吸收相关基因的mRNA表达量与对照组没有统计学差异(NPCIL1:1.15±0.60 vs 0.80±0.29;ABCG5:3.11±2.70 vs 1.92±1.38;ABCG8:3.65±2.08 vs 2.85±1.33;ACAT2:0.30±0.25vs 0.20±0.16;MTTP:12.35±8.10 vs 8.22±5.74,P>0.05).结论 胆石病人小肠胆固醇吸收相关基因表达差异不是胆石病发生的主要遗传因素.     

胆结石病人肝脏核受体LRH-1及其调控基因表达的研究

目的 研究胆囊胆固醇结石病人肝脏的肝脏受体类似物1(Liver receptor homolog 1,LRH-1)及其调控的三磷酸腺苷结合盒(ABC)转运体家族成员abcg5/8的表达,探讨胆固醇结石病发病的机制.方法 27例胆囊胆固醇结石病人,男6例,女21例;年龄平均52岁.10例无胆石症的胆囊息肉病人为对照,男6例,女4例;平均年龄48岁.测定胆汁脂类成分和计算胆汁胆固醇饱和指数.实时定量PCR法测定肝脏LRH-1及abcg5/8 mRNA的表达量.结果 胆石组LRH-1表达高于对照组(14.18±1.80vs7.22±2.22,P<0.05),胆石组肝脏abcg基因mRNA表达量均较对照组增高(abcg5:49.34±3.68 vs 33.48±2.77,P<0.05)abcg8:38.93±5.70 vs 18.70±3.42,P<0.05).胆石组胆汁呈胆固醇过饱和(1.17±0.02).结论 该研究结果提示人类肝脏LRH-1及其调控的abcg5/8的表达增高与胆囊胆固醇结石形成有关.     

胆固醇息肉病人胆囊黏膜ABCG1表达的研究

目的:探讨ABCG1基因在胆囊黏膜中的表达与胆固醇息肉病的关系。方法:采集15例胆囊胆固醇息肉病病人和8例无息肉无结石之对照组的胆囊黏膜和胆汁。测定胆汁胆固醇、胆汁酸和磷脂含量;real-time PCR测定胆囊黏膜中ABCG1 mRNA的表达;Western印迹法检测胆囊黏膜ABCG1之蛋白表达。结果:胆固醇息肉组胆汁胆固醇饱和指数、ABCG1mRNA表达均较对照组升高(P<0.05);息肉组中胆囊黏膜ABCG1在蛋白水平较对照组同样存在高表达。结论:胆固醇息肉病人之胆囊黏膜ABCG1基因及蛋白高表达,可能在胆固醇息肉疾病的发生、发展中起一定作用。     

肝脏X受体对小鼠胆汁脂质成分与胆固醇代谢基因表达的影响

目的 通过激活小鼠肝脏X受体,观察胆汁脂质成分变化与胆固醇代谢相关基因的表达情况,观察肝脏X受体在胆石病发生中的作用.方法 C57BL小鼠18只,分为2组,分别管饲肝脏X受体激动剂T0901317和安慰剂.分析胆汁脂质成分.实时定量PCR法测定肝脏与腹腔巨噬细胞的胆固醇代谢相关基因mRNA表达量.结果 实验组胆汁胆固醇摩尔百分比较对照组升高89%.实验组肝脏组织Abcg5、Abcg8、Abca1与Srebp1表达显著高于对照组:Abcg5为2.96±0.55比1.10±0.22(P＜0.01);Abcg8为0.86±0.16比0.29±0.07(P＜0.01);Abca1为8.45±1.06比5.51±0.84(P＜0.05);Srebp1为14.08±3.18比3.06±0.74(P＜0.01).腹腔巨噬细胞Abca1表达实验组高于对照组(27.66±7.18比8.39±3.65,P＜0.05).结论 肝脏X受体激活使胆固醇逆转运增强,肝脏摄取的过多胆固醇通过胆汁清除,导致胆汁胆固醇含量升高,提示肝脏X受体在胆石病发生中有重要作用.     

ABCG5和ABCG8与胆固醇结石形成的关系

目的探讨ABCG5和ABCG8与结石形成的关系。方法测定结石组病人结石胆固醇含量,确定为胆固醇结石。比较禁食情况下胆固醇结石病人和胃癌病人中血脂、脂蛋白的差异,采用实时PCR方法比较胆固醇结石病人与胃癌病人ABCG5和ABCG8mRNA的差异。结果两组病例血脂、脂蛋白比较无明显差异。胆固醇结石组ABCG5/beta-actin和ABCG8/beta-actin均高于胃癌组(为17.6%±9.8%vs13.5%±6.2%,P<0.01;18.9%±7.1%vs16.5%±4.2%,P<0.01),说明胆固醇结石病人在基础情况下ABCG5和ABCG8有较高的转录水平。结论本研究提示胆固醇结石的形成与肝脏ABCG5和ABCG8高表达,向胆汁中转运较多的胆固醇有关。     

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.     

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.