小鼠异位小肠移植模型的建立

目的 探讨稳定的小鼠异位小肠移植模型制作方法,为小肠移植排斥反应的研究提供良好的实验工具.方法 选用C57BL/6小鼠作供体和BALB/c小鼠作受体进行同种异基因型异位节段性小肠移植.采用小肠供体的门静脉与受体下腔静脉端侧吻合,供体带主动脉片的肠系膜上动脉与受体腹主动脉端侧吻合,供体近端肠管结扎,远端与受体空肠端侧吻合的方式建立异位小肠移植.术后禁食3天,不禁饮,每天分两次经皮下分别给予5%葡萄糖生理盐水2 mL,术后不使用抗生素和免疫抑制剂.小鼠存活超过5 d视为手术成功.结果 共行小肠节段性移植30例,术后5 d存活率达70%(21/30).供体手术时间(41±5.5)min,热缺血时间约0.5 min,供体肠段肠系膜上动脉组织片修整时间约为3 min,供体冷保存时间为(30±7.5)min,受体手术时间(90±7.5)min,其中腹主动脉及下腔静脉阻断时间为(40±3.0)min,静脉吻合时间(10±2.0)min,动脉吻合时间(15±2.5)min,成活小鼠受体手术平均出血量约0.2 mL.手术失败的9例小鼠的死亡原因为动脉吻合口部位狭窄及吻合口处血栓形成(6例),吻合口出血导致出血性休克(2例)和术后腹腔内感染(1例).结论 良好的供体肠段的获取、高质量的血管吻合和肠道吻合及供、受体补液是提高小鼠小肠移植手术成功率的关键.     

大鼠肾移植模型手术改良技巧探讨

目的探讨大鼠肾移植模型手术的改良方法。方法供体Sprague-Dawley(SD)大鼠21只,受体Wistar大鼠42只。采用双侧供肾。受体左肾切除后借助自制导管,行受体肾动脉与供体肾动脉、受体肾静脉与供体下腔静脉端端吻合,供体输尿管带膀胱瓣与受体膀胱吻合,最后切除右肾,腹腔内注入头孢米诺10 mg,关腹。记录手术时间,动、静脉吻合时间,冷、热缺血时间等手术数据;术后大鼠存活3 d认为模型建立成功,计算建模成功率,分析死亡原因。结果供体手术时间为(32.7±5.6)min,供肾修整时间为(4.2±1.1)min。受体手术时间为(42.3±4.9)min,其中动脉吻合时间为(10.1±3.2)min,静脉吻合时间为(13.9±2.5)min,尿路重建时间为(6.3±1.4)min。热缺血时间为(5.4±1.8)s,冷缺血时间为(56.2±7.3)min。42只受体大鼠中,建模成功40只,成功率为95%。另2只受体大鼠死亡,其中1只死于血管吻合口出血,1只死于尿瘘引致的腹膜炎。结论采用改良的血管端端吻合法建立大鼠肾移植模型具有操作简单、手术时间短、成功率高的特点。     

大鼠小肠移植模型的改进

目的：在传统小肠移植模型基础上改进操作方法并试图建立一个操作简便、并发症少、稳定的大鼠小肠移植模型.方法：显微镜下切取供肠的范围包括近端空肠、门静脉及其带肠系膜上动脉的腹主动脉袖.动脉吻合采用供体带肠系膜上动脉的腹主动脉袖与受体的腹主动脉端侧吻合,静脉吻合采用供体的门静脉用袖套法与左肾静脉端端吻合,移植肠两端造瘘.结果：正式实验100次,手术成功率91%.供体手术控制在50 min以内,受体手术控制在80 min以内,手术时间约为150 min.结论：完全在显微镜下建立大鼠小肠移植模型并将手术方法加以改进能在手术视野清晰、术中操作定位准确、局部创伤小的基础上使手术时间缩短,并发症更少,存活率更高.     

简化的大鼠异位全小肠移植术

目的:建立简化的大鼠异位全小肠移植术技术,以提高手术成功率,为相关研究奠定基础.方法:供、受体均为雄性近交系Wistar大鼠,共180只,配对手术.采用供肠的肠系膜上动脉与受体肾下腹主动脉端侧吻合、门静脉与受体左肾静脉套管法端端吻合重建移植小肠血供,移植小肠远端腹壁造口.结果:手术耗时130min,移植小肠热缺血时间约30min.90只受全大鼠术扣即时存活率为100%,长期存活率(＞7d)为95.6%.结论:简化术式具有操作简便,移植小肠的热缺血时间短,手术成功率高等优点,有利于后续研究工作的开展.     

简单条件下大鼠肾移植模型的建立

目的探讨在简单条件下,稳定的、用于移植后早期免疫功能等实验研究的大鼠肾移植模型的建立方法。方法以Wistar大鼠为供体,Sprague Dawley大鼠为受体。取供体大鼠左肾,移植物包括与肾静脉相连的下腔静脉段,与肾动脉相连的腹主动脉段,以及与输尿管相连的供体膀胱瓣,经腹主动脉原位低温灌注6～8mL4℃肝素生理盐水。受体手术于裸眼下完成,供体下腔静脉与受体下腔静脉、供体腹主动脉与受体腹主动脉行端侧吻合,供体输尿管带膀胱瓣与受体膀胱两定点连续缝合。结果共完成50例异体肾移植大鼠模型,存活41例,手术成功率82%,存活时间（6.3±1.6）d。供体手术时间（44.8±7.4）min、受体手术时间（59.0±6.6）min、动脉吻合时间（15.9±2.3）min、静脉吻合时间（14.2±2.7）min、尿路重建时间（5.3±0.8）min、热缺血时间（55.7±4.5）s和冷缺血时间（55.1±5.9）min。结论建立此模型所需要的实验条件简单,术者容易掌握,移植成功率高。     

大鼠小肠移植模型的改进

目的　通过改进技术 ,建立一种简便稳定存活率高的大鼠异位节段小肠移植模型。方法　“无损伤”游离 ,原位冷灌注 ,切取带有腹主动脉和肠系膜上静脉并门静脉的节段小肠 ,4℃乳酸林格氏液保存 1h。游离受体左肾静脉 ,切除左肾。采用显微外科技术行供体腹主动脉对受体腹主动脉的端侧吻合 ,门静脉与受体左肾静脉行袖式吻合。移植肠近端关闭 ,远端外置。结果　共进行 87次移植实验 ,其中 2 6次为正式实验。动脉、静脉吻合时间分别为 2 5～ 30min和 5min。 2 6只受体鼠中2 1只存活超过 3d ,平均存活 (8.93± 2 .5 9)d ,最长存活时间为 14d。结论　良好的血管吻合和充分补充液体是手术成功、移植肠具有良好活力的关键因素     

大鼠原位小肠移植模型的建立与改进

目的探讨建立一种简便稳定存活率高的大鼠原位小肠移植模型。方法整块切取带有腹主动脉和肠系膜上静脉并门静脉的节段小肠,术中原位冷灌注,4℃乳酸林格液保存。动脉吻合采用显微外科技术行供体腹主动脉对受体腹主动脉的端侧吻合,利用Cuff套管技术将供体的门静脉与受体的左肾静脉端端吻合。移植肠远、近端分别与受体肠行端端吻合。结果建立小肠移植模型1 6次,动脉、静脉吻合时间分别为(2 5±5)m in和(4±1)m in。1 6只受体鼠中1 3只存活超过5 d,平均存活(1 0.3 5±2.8 4)d,最长存活时间为2 1 d。结论移植肠的获取、血管吻合技术、肠吻合技术和维持良好的血容量是手术成功的关键。该模型的成功建立,为小肠移植的基础研究提供了良好的动物模型。     

大鼠辅助性肝-小肠联合移植模型

目的　介绍一种新的大鼠辅助性肝 -小肠联合移植模型。方法　整块切取全部小肠和6 0 %的肝脏。同时切取腹腔动脉及肠系膜上动脉的动脉段以确保移植器官的血供。供体小肠的静脉血通过供体完整的门静脉回流。将供体左肾静脉水平肝下下腔静脉斜形切断吻合于受体两肾静脉之间的下腔静脉 ,供体腹主动脉和受体腹主动脉端侧吻合。切除受体的小肠 ,通过小肠端 -端吻合重建肠道。结果　整个手术时间平均为 130min。 3个月的生存率为 8% (16 2 0 )。移植后 90d ,对 3只大鼠行剖腹探查及组织学检查 ,观察到移植物的形态及功能均正常。观察移植后 12个月的 5只大鼠 ,肝功能正常 ,移植肝及小肠均呈正常的组织学结构。结论　大白鼠辅助性肝 -小肠联合移植是可行的。     

三套管法大鼠原位小肠移植动物模型的改进

目的 对三套管法大鼠原位小肠移植动物模型进行改进,提高原位小肠移植的成功率.方法 取106只SD大鼠作为供、受体进行同种同基因原位无造瘘全小肠移植,动静脉吻合采用改良三套管法,其中受体肠系膜上静脉套管采用手术显微镜下套管.供体小肠近端与受体近端空肠端端吻合,远端与受体升结肠端端吻合.手术后存活超过3d即认为手术成功.结果 手术成功率为90.6％ (48/53),供体小肠热缺血时间为0,冷缺血时间为(30±2.48) min,手术成功后7d存活率为97.9％ (47/48).结论 在三套管技术的基础上,采用手术显微镜辅助下肠系膜上静脉套管,大大提高了该动物模型的成功率,缩短了手术技术的成熟时间.     

大鼠辅助性肝—小肠联合移植模型

目的 介绍一种新的大鼠辅助性肝－小肠联合移植模型。方法 整块切取全部小肠和60％的肝脏。同时切取腹腔动脉及肠系膜上动脉的动脉段以确保移植器官的血供。供体小肠的静脉血通过供体完整的门静脉回流，将供体左肾静脉水平肝下下腔静脉斜形切断吻合于受体两肾静脉之间的下腔静脉，供体腹主动脉和受体腹主动脉端侧吻合。切除受体的小肠，通过小肠端－端吻合重建肠道。结果 整个手术时间平均为130min。3个月的生存率为8％（16／20）。移植后90d，对3只大鼠行剖腹探查及组织这检查，观察到移植物的形态及功能均正常。观察移植后12个月的5只大鼠，肝功能正常，移植肝及小肠均呈正常的组织学结构。结论 大白鼠辅助性肝－小肠联合移植是可行的。     

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 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.     

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.     

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.     

Dilemma of Membrane Biocompatibility and Reuse

Abstract: Numerous articles have been published on the multiple use of dialyzers and on the effect of different reprocessing chemicals and techniques on the dialyzer biocompatibility and performance. The results often appear contradictory, especially those comparing standard biocompatibility parameters. Despite this confusion, a discerning review of the published works allows certain limited conclusions to be drawn. Reprocessing of used hemodialyzers changes the biocompatibility profile of a dialyzer as defined by the parameters complement activation. leukopenia, and cytokine release. The effect of reprocessing depends on the chemicals and reprocessing technique applied and also on the type of membrane polymer being subjected to the reprocessing procedure. Reports of pyrogenic reactions indicate that the flux of the membrane also influences how suitable it is for safe reuse. An increased risk of allergic and pyrogenic reactions appears to be associated with dialyzer reuse. Furthermore, there has been a lack of investigations into the immunologic effect of the layer of adsorbed and chemically altered proteins that remains on the inner surface of reprocessed dialyzers. We conclude that the clinical benefit of dialyzer reuse cannot be generally accepted from a biocompatibility point of view.     

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.     

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.     

The analgesic effect of racemic ketamine in patients with chronic ischemic pain due to lower extremity arteriosclerosis obliterans

Background : Ketamine in sub-dissociative doses has been shown to have analgesic and phantom-Limb pain, where conventional treatment has often failed. Chronic ischemic pain due to lower extremity arteriosclerosis obliterans often responds poorly to analgesics, and the pain-generating mechanisms are not well understood.
Methods : Eight patients with rest pain in the lower extremity due to arteriosclerosis obliterans were given sub-dissociative doses of 0.15, 0.30, or 0.45 mg/kg racemic ketamine and morphine 10 mg as a 5-min infusion on four separate days in a cross-over, double-blind, randomised protocol. Plasma levels of (S)- and (R)-ketamine and their nor-metabolites were analysed with an enantioselective high-performance liquid chromatography (HPLC) method. Pain levels were evaluated with a visual analogue scale (VAS).
Results : Individual pain levels were highly variable during and after all the infusions but the pooled pain levels showed a dose-dependent analgesic effect of ketamine with a transient but complete pain relief in all patients at the highest dose (0.45 mg/ kg). Side-effects, mainly disturbed cognition and perception, were pronounced and dose-dependent. Morphine 10 mg had an analgesic peak at 20 min and 5/8 patients had complete pain relief. The remaining 3 patients also had high baseline pain scores, indicating a higher analgesic potency for the 0.30 and 0.45 mg/ kg ketamine doses than for morphine 10 mg.
Conclusion : We have demonstrated a potent dose-dependent analgesic effect of racemic ketamine in clinical ischemic pain. Due to a narrow therapeutic window, this analgesic effect is probably best utilised in combination with other analgesics.