脑内胰岛素与围术期神经认知障碍相关性的研究进展北大核心CSCD

围术期神经认知障碍(PND)是老年患者常见的围术期并发症,表现为注意力不集中,学习能力下降和记忆受损,严重影响患者生存质量,增加社会和家庭负担。PND是多种因素共同作用的结果,脑内胰岛素信号通路异常或胰岛素抵抗是PND发生的重要原因之一。脑内胰岛素具有调节能量代谢、促进神经元再生以及改善记忆和认知等作用,其功能失调可能导致老年患者发生认知障碍。麻醉及手术等破坏脑内胰岛素功能,引发神经炎症反应、突触功能受损、β淀粉样蛋白沉积和tau蛋白过度磷酸化等病理变化,最终导致PND。因此,本文就脑内胰岛素对PND的影响进行综述,以期为探究PND的发病机制和寻找新的治疗靶点提供参考。     

补体系统在围术期神经认知障碍中的研究进展

围术期神经认知障碍（PND）是一种常见的围术期神经系统并发症,表现为注意力不集中,学习能力下降和记忆受损,可影响患者术后短期功能恢复及预后,延长患者的住院时间。目前PND的发生机制仍存在争议。补体系统是一种生物级联反应体系,已被证实在多种神经退行性疾病的发生发展过程中起着重要作用。麻醉及手术刺激可激活中枢神经系统中的补体系统,影响神经炎症反应、突触功能、血脑屏障、血脑脊液屏障,引起或加重PND。本文章就补体系统对围术期神经认知功能的影响做一系统综述,以期为PND的潜在药物靶点和治疗提供参考。     

迷走神经刺激影响器官功能的研究进展

迷走神经是副交感神经系统的主要承担者,可以调控炎症反应及器官功能。围术期手术和麻醉等刺激可导致机体迷走神经张力相对降低,导致围术期循环、呼吸、消化、神经等系统相关并发症的发生率升高。本文就迷走神经张力降低对围术期多器官功能的影响及迷走神经刺激在器官功能中的应用做一综述,为减少围术期各种并发症的发生提供新思路。     

炎症反应在围术期神经认知障碍中的作用研究进展

围术期神经认知障碍(PND)患者有发生严重并发症的风险,可能出现痴呆甚至死亡。目前,关于发生PND的具体机制尚不明确。越来越多的研究表明,PND患者和动物模型中出现促炎信号分子。外周炎性因子的释放、血脑屏障的破坏、中枢神经炎症反应的发生、神经元的凋亡和突触的丧失,提示炎症机制可能在PND的发生中起关键作用。本文对神经炎症反应在PND中的作用以及干预措施的研究进展作一综述,以期为基础研究及临床实践提供新的思路。     

自噬在绝经后骨质疏松中作用的研究进展

绝经后骨质疏松症是临床上较为常见的疾病,严重影响许多老年女性生活质量。研究表明,自噬参与了绝经后骨质疏松的发生与发展。在机体衰老、雌激素水平下降及氧化应激水平增高等多种因素的影响下,骨组织细胞的自噬活性发生改变,进而导致了骨代谢及骨稳态的调节失控,并进一步导致骨质疏松的发生。自噬在细胞增殖、分化、凋亡及维持细胞稳态等多方面发挥重要作用,尤其也参与了促骨形成及促骨吸收的过程。近年来随着对自噬研究的不断深入,自噬活性的调控通路及其在细胞中作用的研究取得了众多进展。在查阅大量国内外的相关文献后,本文对自噬在绝经后骨质疏松症发病机制中所发挥的作用进行综述,并对自噬与骨形成、骨吸收的关系进行总结。     

线粒体自噬的调控分子在不同病生理过程中的作用机制研究进展

线粒体自噬与许多疾病的病理过程相关联,了解细胞自噬在不同疾病的病理过程中的具体机制具有重要意义。本文拟对细胞自噬的三种调控方式在不同疾病的病理生理过程中的作用进行综述。探讨线粒体自噬受体NIX/BNIP3和FUDNC1 以及 PINK1/Parkin 途径在神经退行性疾病、糖尿病、细胞死亡、炎症和缺血再灌注损伤中调控机制。明确细胞自噬在疾病中的调控机制,为疾病的诊治提供理论基础。     

肠道菌群紊乱与围术期神经认知障碍的研究进展

正随着手术麻醉的普及和医学人文的发展,围术期神经认知障碍(perioperative neurocognitive disorders,PND)受到越来越多的关注。2018年11月麻醉学领域6大权威期刊同步刊发关于PND的最新定义,明确PND是指发生在术前和术后12个月内,且符合第五版神经障碍手册(diagnostic and statistical manual of mental disorders-fifth edition,DSM-5)中神经认知障碍诊断标准的围术期认知功能损害[1]。PND好发于老年患者,主要表现为注意力、记忆力、语言思维能力等减     

细胞自噬在认知功能障碍机制中的研究进展

认知功能障碍是各种原因导致的认知功能损害,严重影响患者的生活质量。高龄、既往心脑血管疾病、麻醉及手术等均是其危险因素。细胞自噬是维持细胞能量稳态必需的细胞内降解途径,与应激、感染、癌症及神经退行性疾病等密切相关。近年来大量研究表明,细胞自噬在认知功能障碍机制中发挥重要作用。神经元内自噬水平异常会破坏细胞稳态,严重时可影响患者的认知功能。通过调控各种细胞自噬信号通路可明显改善细胞缺氧、促进能量及物质代谢,改善认知功能,以上为临床认知功能障碍的预防和治疗提供了新的思路。     

自噬在骨质疏松与骨稳态中作用的研究进展

骨质疏松症是与年龄相关的全身系统性骨代谢疾病。随着年龄增加,骨形成受抑制骨破坏增加导致骨量降低与骨折易感性。骨质疏松症形成的分子机制较为复杂,其中自噬与骨质疏松形成之间的关系一直是近年热点研究话题。自噬是高度保守的真核细胞物质循环过程,通过降解大分子物质、蛋白质、细胞器,并对降解产物循环利用,保持细胞在应激、能量缺乏等不利环境中稳定生存。随着人们对自噬研究的不断拓展,自噬水平的分子调控通路及其在细胞生理与疾病发展中的作用取得了众多进展,包括神经退行性疾病、癌症、糖尿病、心肌疾病等。许多动物体内外及人体研究显示自噬与包括骨质疏松症在内的骨骼疾病存在着很大关联。自噬在骨组织各细胞增殖、分化、凋亡及保持稳定等多方面扮演重要角色,深度参与骨重塑过程。骨组织各细胞在衰老、活性氧累积、雌激素水平下降、全身炎症水平增高等多种不利因素影响下,自噬水平发生不同程度的改变,导致骨代谢与骨稳态失衡并逐步发展为骨质疏松症。该文在现有的相关文献报告基础上,对自噬与骨稳态、骨质疏松症的关系进行综述,以期对进一步研究提供参考。     

细胞自噬与炎症小体相互作用的研究进展

细胞自噬是真核生物细胞内普遍存在的一种自我维持内环境稳定的机制,并在多种生理活动中发挥重要作用,如生存、发育、细胞自我保护等。炎症小体是胱天蛋白酶活化平台,并促进某些促炎因子如IL-1β、IL-18的成熟和分泌,启动机体的固有免疫反应。自噬与炎症小体关系密切,炎症小体能够诱导自噬的发生,自噬对炎症小体也有调控作用。现就细胞自噬和炎症小体的相互作用作一综述。     

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.     

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.     

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.     

Is the recovery profile of mivacurium independent of the rate of decay of its plasma concentration in patients with normal plasma cholinesterase activity?

Background: The duration of action of muscle relaxants is poorly correlated to the rate of decay of their plasma concentration. The plasma concentration of mivacurium may rapidly decrease below its active concentration because of the extensive hydrolysis of mivacurium. By inflating a tourniquet on one upper limb for 3 min after the administration of atracurium, mivacurium or vecuronium, we studied the influence of the initial decline of their plasma concentration on their effect. Methods: In 50 patients anaesthetised with thiopental, isoflurane and fentanyl, the effect of bolus doses of 0.15 or 0.25 mg . kg^?1 mivacurium (MIV 15, MIV 25), 0.3 or 0.5 mg . kg^?1 atracurium (ATR 30, ATR 50) and 0.06 or 0.1 mg . kg^?1 vecuronium (VEC 06, VEC 10) were measured on both arms (evoked response of the adductor pollicis to train-of-four stimulation every 12 s), a tourniquet being applied on one arm just before and during 3 min after the muscle relaxant bolus. Results: Tourniquet inflation of 3 min almost abolished the neuromuscular effect of mivacurium. In the vecuronium groups and in the ATR 50 group, tourniquet inflation did not modify the maximum degree of depression of the twitch response. Also, the duration of action of vecuronium was unaffected by the tourniquet. In the ATR 30 group, times to return of the twitch response to 25% (duration 25%) and 75% (duration 75%) of control response were significantly shorter in the cuffed arm, 23 min vs 27 min, and 41 min vs 45 min, respectively. In the ATR 50 group, only duration 25% was significantly shorter in the cuffed arm (41 min vs 45 min). Conclusion: The results suggest that the rate of decline of the plasma concentration of mivacurium is so rapid, that a very low and almost clinically ineffective concentration is present as soon as 3 min after its administration. The results also indicate that the recovery from a mivacurium-induced neuromuscular blockade is not influenced by the rate of decay of its plasma concentration in patients with genotypically normal plasma cholinesterase.     

Membranes in Artificial Organs

Abstract: Membrane processes play a pivotal and enabling role in modern replacement therapy for acute and chronic organ failure and in the management of immunologic diseases. In fact, virtually all contemporary extracorporeal blood purification methods employ membrane devices, and the next generation of artificial organs and tissue engineering therapies are almost certain to be similarly grounded in membrane technology. In this short essay, we comment on the similarities and differences among synthetic membranes and their natural counterparts and also provide a critical overview of the demographics and technology of hemodialysis, hemofiltration, apheresis, oxygenation, and emerging membrane technologies and applications.     

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.