胸腺注射供体脾细胞诱导移植心脏免疫耐受的实验研究

目的探讨诱导心脏移植免疫耐受的方法及其产生的可能机制. 方法采用大鼠腹部心脏移植模型,随机分成未处理(Ⅰ)组,胸腺注射供体脾细胞(Ⅱ)组,腹腔注射兔抗鼠淋巴细胞血清(Ⅲ)组,胸腺注射供体脾细胞联合应用兔抗鼠淋巴细胞血清(Ⅳ)组,每组6只大鼠.Ⅱ、Ⅳ组在移植前2 1 d将供体脾细胞2.5×107个注射到受体胸腺,Ⅲ、Ⅳ组受体腹腔注射兔抗鼠淋巴细胞血清(ALS)1 ml,然后行异位心脏移植.观察移植心脏存活时间,供心病理学改变及供、受体间的混合淋巴细胞反应(MLR). 结果Ⅳ组供心平均存活时间(MST)为(81.8±7.6)d,较Ⅰ组(7.3±1.0)d、Ⅱ组( 7.8±1.0)d、Ⅲ组(8.2±1.2)d显著延长,差异有显著性意义(P＜ 0.01 );供心仅见少量炎性细胞浸润;供、受体间MLR较正常对照组显著降低,差异有显著性意义(P＜0.01). 结论胸腺注射供体脾细胞联合应用ALS能成功诱导心脏移植的免疫耐受;胸腺内特异性T细胞克隆消除可能与免疫耐受的形成有关.     

大鼠胸腺内注射同种抗原对甲状旁腺移植物存活的影响

目的　改善甲状旁腺移植物的存活时间。方法　用SDLewis及DA大鼠进行甲状旁腺移植实验。由供体Lewis大鼠的脾细胞提取抗原。按照不同的抗原注射途径（尾静脉、门静脉及胸腺内）,是否合用抗淋巴细胞血清及第3品系大鼠的甲状旁腺移植共分为9组。结果　胸腺内注射抗原结合抗淋巴细胞血清的应用，使甲状旁腺移植物的平均存活期达到（196.00±3.96）d，与其他各组相比差异有非常显著性（P＜0.01）。结论　大鼠胸腺内注射抗原结合抗淋巴细胞血清的应用成功地诱导受体产生了供体特异性免疫耐受。     

供体脾细胞胸腺注射对大鼠肢体移植存活的研究

目的 :通过大鼠肢体移植模型 ,旨在分析供体脾细胞注射对大鼠肢体移植中免疫耐受的诱导作用。方法 :选择雄性Wistar和SD大鼠为供、受体 ,对照组为胸腺注射脾细胞培养液 ,实验组为供体脾细胞注射 ,进行了 1 6例异体肢体移植动物实验。观察大鼠移植肢体排斥反应时间及存活时间。结果 :对照组肢体平均存活时间为 ( 9.38± 1 .92 )d ;实验组移植肢体存活时间为 ( 1 5.38± 2 .97)d。结论 :供体脾细胞胸腺注射大鼠肢体移植术后能够明显延长移植肢体的存活时间。     

大鼠脾移植诱导特异性免疫耐受效果

目的 比较异位脾移植和原位脾移植诱导特异性免疫耐受的效果.方法 建立大鼠异位脾移植和原位脾移植模型6周后,二期行同源心脏移植,比较移植心脏的存活时间和移植5d后的排斥反应强度.以单纯心脏移植组和心脏移植+环孢菌素组作为对照组.结果 移植心脏存活时间:心脏移植+环孢菌素组＞原位脾移植组＞异位脾移植组＞单纯心脏移植组(P＜0.05).术后第7天排斥反应强度和混合淋巴细胞反应强度测定:心脏移植+环孢菌素组＜原位脾移植组＜异位脾移植组＜单纯心脏移植组(P＜0.05).结论 由于脾脏的生理功能与门静脉系统的回流特点有关,较之于异位脾移植,原位脾移植能更为有效地诱导受体特异性免疫耐受状态.     

供者肝脏非实质细胞输注诱导免疫耐受模型的建立

目的探讨供者肝脏非实质细胞输注诱导受者特异性免疫耐受的效果.方法将2×107个C3H/HE小鼠的肝脏非实质细胞通过尾静脉输入C57BL/6小鼠的体内,48*!h后给其腹腔注射环磷酰胺200*!mg/kg,18*!d后接受C3H/HE小鼠的皮片移植,观察皮片的存活情况.于肝脏非实质细胞输注前及输注后18*!d、30*!d、60*!d进行供、受者混合淋巴细胞培养.结果15只输注C3H/HE小鼠肝脏非实质细胞的C57BL/6小鼠,其移植皮片的存活时间明显延长(74.6*!d±9.7*!d,对照组仅存活10*!d±0.4*!d);混合淋巴细胞培养的结果证实受者的T淋巴细胞对供者小鼠淋巴细胞的反应程度明显降低.结论肝脏非实质细胞可以有效诱导免疫耐受.     

门静脉注射供体脾细胞诱导大鼠移植肾长期存活

目的 :探讨门静脉内注射供体脾细胞诱导移植肾的免疫耐受情况。方法 :实验组 Wistar大鼠在肾移植同时将经过预处理的供体 SD大鼠脾细胞注入门静脉 ,对照组则注入生理盐水 ,然后用环孢素 A治疗 1周 ,并以大鼠平均存活时间为标准比较两组结果。结果 :对照组平均存活( 1 0 .5± 2 .1 ) d,实验组为 ( 72 .2± 32 .0 ) d( P <0 .0 1 )。实验组在肾移植 60 d后 ,再移植 SD大鼠和Lewis大鼠的皮肤 ,发现 SD大鼠的皮肤不被排异 ,Lewis大鼠的皮肤出现排异。结论 :门静脉内注射供体脾细胞可诱导肾移植免疫耐受 ,并且这种耐受具有特异性。     

腹腔注射豚鼠血管内皮细胞诱导豚鼠-大鼠心脏移植免疫耐受的研究

目的探讨腹腔注射豚鼠血管内皮细胞诱导豚鼠-大鼠心脏移植免疫耐受的可行性.方法心脏移植前14 d注射豚鼠血管内皮细胞至大鼠腹腔,观察豚鼠心脏存活时间.供心标本行苏木素-伊红(HE)染色和IgM、C3免疫组织化学检查.A组为实验对照组.B组给予2×106个豚鼠血管内皮细胞.C组予以肌注环磷酰胺(CY)40 mg/kg体重.D组为腹腔注射内皮细胞2.5×106个联合肌注CY 40 mg/kg体重组.结果腹腔注射豚鼠血管内皮细胞明显延长供心存活时间[B组为(35.12±5.24)min,与A组(14.75±7.22)min比较,差异有非常显著性(P＜0.001),与C组(42.34±5.43)min比较,P＜0.05].联合使用CY与内皮细胞能促进诱导耐受[(50.33±6.21)min],C组与D组相比P＜0.05.各组的病理表现为典型的超急性排斥反应改变.结论腹腔注射豚鼠血管内皮细胞具有延长供心存活时间,诱导免疫耐受的作用.联合使用环磷酰胺与内皮细胞能促进诱导免疫耐受.     

供者基因转染受者细胞诱导特异性免疫耐受的实验研究

目的　探讨供体特异性基因片段MHCClassI类抗原分子RT1.AacDNA在诱导免疫耐受中的作用和可能机制。方法　采用大鼠同种异体心脏异位移植模型,通过供体MHCClassI类抗原的RT1.AacDNA基因片段转染受体成肌细胞（MB）并接种自体胸腺,观察移植物存活时间,判断受体免疫耐受产生和维持的状态。结果　经胸腺接种转染供体基因的自体成肌细胞并同时服用CsA,移植物平均存活时间高达(96.13±12.91)d,明显高于其它实验组（P＜0.05）;动态混合淋巴细胞反应（MLR）,无论外周输注或胸腺接种其对照组cpm值均高于各自实验组;CD4     

嵌合体在同种心脏移植免疫耐受中的作用

目的探讨嵌合体在同种心脏移植免疫耐受中的作用.方法采用大鼠腹部心脏移植模型,将30只Lewis大鼠随机分成正常对照组(Ⅰ组)、排斥反应组(Ⅱ组)、免疫耐受组(Ⅲ组),每组10只.观察移植心存活时间,供心病理学改变,供、受者间的混合淋巴细胞反应(MLR)和脾、胸腺嵌合体.结果Ⅲ组供心平均存活时间(85.28±7.48天)较Ⅱ组(7.33±1.03天)显著长(P＜0.01);Ⅱ组供心见大量炎性细胞浸润,Ⅲ组供心仅见少量炎性细胞浸润;Ⅲ组供、受者间MLR较Ⅰ组显著低(P＜0.01);Ⅲ组受者的脾、胸腺形成了稳定的供者细胞嵌合体.结论移植免疫耐受的受者形成了稳定的中枢和外周嵌合体,嵌合体的形成对移植耐受起重要的作用.     

大鼠T细胞疫苗的制备及其抗移植皮肤排斥作用的实验研究

目的 探讨T细胞疫苗(TCV)的制备方法及其抗移植皮肤排斥反应的作用.方法 制备针对特定SD大鼠的供体特异性T细胞疫苗,将其免疫受体Wistar大鼠;然后取免疫前和每次免疫后第五天的受体Wistar的淋巴细胞(反应细胞)与供体SD的淋巴细胞(刺激)进行体外单向混合淋巴细胞反应(MLR),以MTT法检测细胞免疫增值反应情况,比较疫苗接种后诱导淋巴细胞反应受抑制的情况:再将SD大鼠皮肤移植到TCV免疫后的Wistar大鼠,观察皮肤移植反应并统计移植物存活的时间.排斥反应的移植物行病理检查.结果 TCV组受体淋巴细胞反应程度比接种前显著减弱(P＜0.05);特异性TCV组皮肤移植物存活时间较非特异性TCV组及对照组延长(P＜0.05).移植皮肤排斥反应病理表现更轻.结论 TCV经腹腔接种可以诱导出针对同种抗原特异性免疫耐受,TCV能够延长同种异体移植皮肤的存活时间,有一定抗移植排斥反应作用.     

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.