芬太尼联合七氟烷后处理对离体大鼠缺血/再灌注心功能的影响

目的 研究芬太尼联合七氟烷后处理对离体大鼠缺血/再灌注(ischemia/reperfusion,I/R)心脏心功能的影响.方法 建立离体大鼠心脏缺血40 min,再灌注120 min模型.根据再灌注开始10 min的不同处理,使用随机数字表法将实验动物随机分为4组(n=10):I/R对照组(Con),七氟烷后处理组(...     

丙泊酚对全脑缺血/再灌注损伤大鼠保护作用研究

目的探讨丙白酚对大鼠全脑缺血/再灌注损伤（ischemia/reperfusion injury,I/RI）的保护作用。方法65只Wistar雄性大鼠采用完全随机法分为5组：假手术组（S组）、缺血/再灌注(ischemia/reperfusion,I/R)组(I/R)组、丙泊酚组1(P1)、丙泊酚组2(P2)、丙泊酚组...     

缺血预适应在外科领域的研究进展

缺血预适应(ischemic preconditioning.IPC)指的是一种通过预先反复短暂缺血以延缓或减轻组织后续缺血再灌注损伤的现象。作为机体对于缺血／再灌注(ischemia／reperfusion，I／R)损伤的一种内源性保护现象，IPC的保护作用不仅存在于心脏。而且存在于机体的其他重要组织器官。有关IPC现象及其机制的研究将为外科手术抗I／R损伤治疗提供更有价值的理论基础。     

雷帕霉素减弱七氟烷预处理对心肌缺血/再灌损伤的保护作用

目的 观察自噬增强剂雷帕霉素(rapamycin,RAPA)对七氟烷预处理离体大鼠心脏缺血/再灌注损伤(ischemia/reperfusion injury,I/RI)保护作用的影响,探讨自噬在七氟烷预处理对心肌I/RI保护中的作用. 方法 36只健康成年雄性Wistar大鼠,体重250 g～280 g,采用随机数字表法分为3组(每组12只):缺血/再灌注(ischemia/reperfusion,I/R)组,七氟烷预处理组(S+I/R组),七氟烷预处理+RAPA组(S+I/R+RAPA组).采用Langendorff灌注装置制备离体心脏I/R模型,缺血30 min、再灌注120 min,记录平衡末及再灌注末的左室舒张末期压(left ventricular diastolic pressure,LVEDP)、左室发展压(left ventricular developed pressure,LVDP)、左心室内压最大上升/下降速率(the maximum rate of increase or decrease of left ventricular pressure,±dp/dtmax)、心率(heart rate,HR).再灌注120 min后,收集冠状动脉流出液测乳酸脱氢酶(lactate dehydrogenase,LDH)活性;取心肌,计算心肌梗死面积百分比.Western blot半定量检测自噬标记物微管相关蛋白1轻链3(microtubule-associated protein 1 light 3,LC3)、RAPA靶蛋白(target of rapamycin,mTOR)及磷酸化mTOR (phosphorylated mTOR,p-mTOR)蛋白表达量. 结果 再灌注末,与I/R组比较,S+I/R组心功能明显改善(P＜0.05),心肌梗死面积[(47±6)％、(29±5)％]、冠状动脉流出液LDH活性[(29±5) U/L、(19±4) U/L]均降低,心肌LC3-Ⅱ表达下调,p-mTOR表达上调(P＜0.05);S+I/R+RAPA组各指标与I/R组比较,差异无统计学意义.与S+I/R组比较,S+I/R+RAPA组心功能各项指标呈损害性变化(P＜0.05)、梗死面积增大[(29±5)％、(46±3)％]、冠状动脉流出液LDH活性[(19±4) U/L、(27±5) U/L]均增加(P＜0.05),LC3-Ⅱ表达水平增加,p-mTOR表达降低. 结论 RAPA能够减弱七氟烷预处理对I/RI产生的保护作用,可能与其降低p-mTOR表达,减弱对自噬的抑制作用有关.     

心肌缺血/再灌注损伤中细胞胀亡产生机制的研究进展

背景 细胞胀亡和凋亡均可出现在心肌缺血/再灌注损伤(ischemia/reperfusion injury,I/RI)过程中.胀亡是一种特殊形式的非凋亡性细胞死亡方式,它的特征表现为细胞肿胀、起泡、细胞器肿胀、细胞膜通透性增加和核溶解. 目的 明确细胞胀亡在心肌缺血/再灌注(ischemia/reperfusion,I/R)发生、发展中的作用将有助于心肌保护研究的深入. 内容 阐述细胞胀亡的生物学特性、发生机制及与心肌I/RI. 趋向 通过对心肌I/RI中细胞胀亡的深入了解和研究,有可能带来心肌保护的新突破.     

阿片受体激动剂预处理对器官缺血/再灌注损伤的保护作用

背景 μ、κ、δ、ε、σ及λ等多种阿片受体广泛存在于体内各器官,它们各自有其特异的内源性配体,发挥不同的生物效应,其对缺血/再灌注损伤(ischemia/reperfusion injury,I/RI)器官的保护作用已引起医学界的广泛关注.目的 综述阿片受体激动剂对I/RI器官的保护作用的研究进展.内容 阿片受体激动剂...     

阿片类药物减轻急性缺血/再灌注损伤及相关机制

背景 缺血预处理对于器官缺血/再灌注损伤（ischemia/reperfusion injury,I/RI）具有强大的保护作用,但其临床应用受到时机以及伦理学的限制.近年来有研究发现阿片类药物预处理以及后处理对组织器官I/RI同样具有保护作用,其既不损伤器官又能产生与缺血预处理相同的效果,是更为可行的治疗措施. 目的 在将阿片类药物处理推广至临床应用前,仍需进行更多大规模的临床研究.拟就阿片类处理减轻I/RI的发展过程及其作用机制进行探讨. 内容 阿片类药物处理I/RI的几种方式及其机制. 趋向 阿片类药物处理比较其他损伤性处理方式更易操作,且对I/RI同样具有保护作用,有望成为日后治疗的热点之一.     

肢体远隔缺血预处理对肝脏缺血/再灌注损伤保护作用的研究进展

背景 肝脏缺血/再灌注损伤(ischemic/reperfusion injury,I/RI)是影响临床肝脏手术和肝脏移植手术术后发病率和病死率的主要因素,肢体远隔缺血预处理(limb remote ischemic preconditioning,LRIPC)可以减轻肝脏I/RI.目的 综述LRIPC对肝脏I/RI保护作用的研究进展.内容 LRIPC的发展、保护作用的机制、保护作用的时相及LRIPC的建模方法.趋向 LRIPC应用于临床防治肝脏I/RI不失为一种可取的方案.     

肢体远隔缺血后处理联合吗啡后处理增强对心肌缺血/再灌注损伤的保护作用

目的 评估联合应用肢体远隔缺血后处理(remote ischemic postconditioning,RIP)和吗啡后处理能否获得增强的心肌保护作用. 方法 采用大鼠在体心肌缺血/再灌注损伤(ischemia/reperfusion injury,I/RI)模型,采用随机数字表法将60只大鼠分为6组(每组10只):空白对照组(Sham组)、缺血/再灌注(ischemia/reperfusion,I/R)组(I/R组)、缺血预处理(ischemic preconditioning,IPC)组(IPC组)、肢体RIP组(RIP组)、吗啡后处理组(M组)以及联合应用肢体RIP和吗啡后处理组(M+RIP组).实验中连续监测心律失常情况,计算缺血期和再灌注早期的心律失常评分,检测血清肌酸激酶同工酶(creatine kinase MB,CK-MB)和心脏肌钙蛋白Ⅰ(cardiac troponin Ⅰ,cTnⅠ)浓度,并采用伊文蓝和氯化三苯基四氮唑(triphenyltetrazolium chloride,TTC)双重染色法测定心肌梗死面积. 结果 I/R组、IPC组、RIP组、M组和M+RIP组的心肌梗死面积分别是(56.0±9.1)％、(23.9±5.5)％、(40.4±11.1)％、(47.7±9.3)％和(27.2±6.7)％.与I/R组比较,M+RIP组再灌注早期心律失常发生率和心律失常评分、血清CK-MB和cTnⅠ浓度以及心肌梗死面积均明显降低(P＜0.05);这些参数在IPC组和M+RIP组之间差异无统计学意义(P＞0.05). 结论 在大鼠在体心肌I/RI模型,联合应用肢体RIP和吗啡后处理可获得增强的心肌保护作用,其心肌保护作用类似于IPC.     

心脏肥大细胞在心肌缺血/再灌注损伤中的研究进展

肥大细胞是一种多效应细胞,起源于骨髓多分化细胞,激活后脱颗粒释放多种炎症介质、细胞因子及蛋白酶,参与炎症反应及IgE依赖的组胺介导的高敏反应.现讨论心脏肥大细胞与心肌缺血/再灌注(ischemia/reperfusion,I/R)损伤中炎症反应、细胞凋亡及梗死修复等病理过程的相关关系.     

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.