他克莫司处理的供者树突状细胞延长大鼠移植心脏的存活时间

目的 研究经他克莫司(Tac)处理的供者未成熟树突状细胞(imEX3)在延长大鼠移植心脏存活时间中的作用和机制.方法 以Wistar大鼠为供者,SD大鼠为受者,行颈部异位心脏移植.心脏移植前将受者随机分为3组,每组15只,进行不同的预处理.第1组:为对照组,术前7 d经受者的尾静脉注射生理盐水1.0ml;第2组:为未经Tac处理组,术前7 d经受者的尾静脉注射未经Tac处理的imDC 2×106(1.0 m1);第3组:为Tac处理组,术前7 d经受者的尾静脉注射经Tac处理的imDC 2×106(1.0 m1).术后观察:移植心脏的存活时间、受者与供者及无关供者(Lewis大鼠)的单向混合淋巴细胞反应(MLR)、心肌组织病理学表现及血清中白细胞介素(IL)-2、IL-4、IL-10和γ干扰素(IFN-γ)的水平变化.结果 第1、2、3组移植心脏的存活时间分别为(8.57±1.34)d、(20.92±2.68)d和(33.30±3.92)d.各组之间比较,差异均有统计学意义(P＜0.01);第2、3组受者对供者的MLR刺激指数较第1组明显降低,而对无关供者的MLR刺激指数则与第1组相近;各组受者血清IL-2、IFN-γ、IL-4、IL-10浓度问差异有统计学意义(P＜0.01),第3组IL-2和IFN-γ(代表TH1细胞)水平明显降低,而IL-4和IL-10(代表TH2细胞)水平明显增高.结论 imDC能够延长大鼠心脏移植后的存活时间,经Tac处理的imDC能够进一步加强这种作用;且imDC所诱导的免疫低反应性是供者特异性的.其机制可能主要与调节T淋巴细胞免疫应答类型(TH1至TH2的免疫偏移)和诱导T淋巴细胞免疫应答降低有关.     

维生素D衍生物联合供者骨髓细胞输注诱导异基因大鼠心脏移植免疫耐受

目的 探讨同种异基因心脏移植后免疫耐受的诱导。方法 建立大鼠颈部异位心脏移植模型，按分组分别给予门静脉输注供者骨髓细胞(DBMC)(B组)、骨化三醇灌胃(C组)、输注DBMC及骨化三醇灌胃(D组)以及环孢素A(CsA)灌胃(E组)。观察移植心脏的存活时间及心肌组织病理改变，测定心肌组织中肿瘤坏死因子及细胞间粘附分子-1 mRNA的表达以及血清钙、磷浓度，进行受者与供者及无关第三品系大鼠脾细胞混合淋巴细胞培养(MLR)。结果 D组移植心脏的存活时间较其它各组显著延长(P＜0．05)；术后7d，C组、D组、E组受者脾细胞均能显著抑制供者及第三方无关供者脾细胞作为刺激细胞引起的MLR；D组手术前后血磷、血钙浓度的差异无显著性(P＞0．05)；各组急性排斥反应的程度，D组最轻；D组肿瘤坏死因子及细胞间粘附分子-1 mRNA的表达受到显著抑制，与对照组(A组)、B、C组比较，差异有显著性(P＜0．05)。结论 骨化三醇灌胃联合DBMC输注可显著延长移植心脏的存活时间，二者具有协同作用。     

器官组织移植

HOE-642联合改良K／Mg冷血心麻液对犬供心的保护作用，心肌细胞移植改善心肌梗死大鼠左心室收缩功能，注射供者的肝匀浆提取液延长大鼠异位心脏移植存活时间，转染IL-12亚基干扰RNA的供者树突状细胞延长同种小鼠移植心脏存活时间,抗CD8单抗与抗CD40L单抗联合应用对小鼠心脏移植后慢性排斥反应的影响[编者按]     

混合培养的供、受者骨髓细胞过继回输延长小鼠移植心脏存活时间

目的 将供、受者骨髓细胞经混合培养后过继回输,以观察其对同种异体移植心脏存活时间和受者免疫功能的影响.方法 取Balb/c小鼠和C57BL/6J小鼠的骨髓细胞,进行混合培养.配制含Balb/c小鼠和C57BL/6J小鼠脾淋巴细胞的混合淋巴细胞反应体系(MLR)以及含Balb/c小鼠和C3H小鼠脾淋巴细胞的MLR,分别加入混合培养的骨髓细胞,观察其对MLR中细胞增殖的影响.以C57BL/6J小鼠为供者,Balb/c小鼠为受者行腹腔异位心脏移植,实验分为4组:(1)移植对照组,受者仅进行心脏移植,不作其他处理;(2)实验对照组,心脏移植后给予西罗莫司灌胃;(3)实验组,移植手术结束前注射混合培养的骨髓细胞1×10~7个,术后给予西罗莫司;(4)第三方对照组,受者接受C3H小鼠的移植心脏,手术结束前注射混合培养的骨髓细胞1×10~7个,术后给予西罗莫司.记录移植心脏存活时间;移植心脏停跳当日,取受者外周血,检测CD4~+ CD25~+ T淋巴细胞的比例及供者来源的H-2K~b细胞的比例.结果 加入混合培养的骨髓细胞后,Balb/c和C57BL/6J的MLR的淋巴细胞增殖率低于Balb/c和C3H的MLR.实验组移植心脏的存活时间长于其他3组(P<0.05).实验组CD4~+CD25~+T淋巴细胞的百分率高于其他3组(P<0.05).实验组外周血中H-2K~b细胞的比例高于其他3组(P<0.05).结论 受者输注混合培养的供、受者骨髓细胞可在一定程度上调节免疫应答,延长小鼠移植心脏的存活时间,该作用具有供者抗原特异性.     

1O-羟基喜树碱和环孢素A诱导异基因大鼠心脏移植受者免疫耐受的实验研究

目的以中药制剂10-羟基喜树碱(HCPT)和环孢素A(CsA)诱导异基因大鼠心脏移植受者免疫耐受,并探讨免疫耐受的特异性和形成机制.方法以纯系SD大鼠为供者,纯系Wis-tar大鼠为受者行异体颈部心脏移植.将移植后50只受者大鼠随机分成5组,分别接受不同剂量HCPT、CsA或二者联合应用.A组接受安慰剂.B组接受HCPT 1.0mg·kg-1·d-1,腹腔注射.C组接受HCPT 2.0 mg·kg-1·d-1,腹腔注射.E组接受CsA10.0 mg·kg·d-1,导管灌胃.F组联合应用HCPT和CsA,方法剂量同B组和E组.心脏移植物长期存活受者术后60 d停用免疫抑制剂,120 d同时行供者来源(SD)大鼠和无关供者(SHR)大鼠皮肤移植.结果3只C组大鼠和5只F组大鼠心脏移植术后停用免疫抑制剂长期存活超过730 d.8块SD大鼠皮肤移植物长期存活超过610 d,而8块SHR大鼠皮肤均被排斥,平均存活时间(4.50±1.25)d.结论大剂量HCPT或小剂量HCPT与CsA联合应用可诱导异基因大鼠心脏移植受者免疫耐受,且形成的免疫耐受具有明确的抗原特异性.     

眼镜蛇毒因子消耗补体对大鼠移植心急性排斥反应的抑制作用

目的研究中华眼镜蛇毒因子(CVF)消耗补体对大鼠心脏移植急性排斥反应的影响。方法以近交系BN大鼠为供者,Lewis大鼠为受者,建立腹腔异位心脏移植模型。实验分为2组,每组8只。CVF组:心脏移植术前3 d、2 d时,经受者尾静脉注射CVF 50μg／kg;术前12 h至移植心停跳时,经尾静脉注射CVF 20μg／kg,每2 d注射1次。对照组:术前、术后不给予受者任何特殊处理。术后观察移植心的存活时间,测定术后第1、3、5和6d及移植心停跳时的血清总补体活性(CH50法)、移植心C3沉积及CD3+T细胞浸润情况,并观察移植心的病理变化。结果CVF组和对照组的移植心存活时间分别为(11．69±0．72)d和(6．65±0．35)d,两组比较,差异有统计学意义(P<0．01)。CVF组移植心组织内C3沉积和CD3+T细胞浸润程度均较对照组同期明显减轻,病理损害程度也较对照组同期明显减轻。结论CVF消耗补体对大鼠心脏移植急性排斥反应起到了明显的抑制作用,从而延长移植心存活时间。     

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.     

异基因小鼠髓腔内骨髓移植诱导免疫耐受

目的探讨异基因小鼠髓腔内骨髓移植(IBM-BMT)诱导免疫耐受的效果。方法雄性BALB/c小鼠和雌性C57BL/6小鼠分别作为骨髓移植的供、受者。受者预处理后进行IBM-BMT,建立异基因小鼠骨髓移植模型。通过皮肤移植和混合淋巴细胞反应(MLR)对受者的耐受状态进行检测。结果接受过IBM-BMT的受者进行供者来源的皮肤移植,移植物的存活时间>300d,较对照组的(12.7±1.63)d明显延长(P<0.01),而受者接受来自无关供者(KM小鼠)的皮肤移植物存活时间未见延长。接受过IBM-BMT的受者脾细胞对供者脾细胞的MLR增殖率均明显降低,与对照组比较,P<0.01,而对无关供者的脾细胞仍表现强烈的增殖反应。结论应用IBM-BMT可以诱导受者获得供者抗原的特异性免疫耐受,使移植物存活时间延长。     

联体共生诱导大鼠心脏移植免疫耐受的实验研究

目的　通过联体共生模型 ,建立供、受者嵌合体 ,探讨嵌合体与免疫耐受的关系。方法　纯系雄性DA(RT1a)大鼠为供者 ,Lewis(RT11)大鼠为受者 ,随机分成 3组 ,每组供、受者各 15只。Ⅰ组 (未处理组 ) :仅行DA到Lewis大鼠的腹部心脏移植 ,手术前后不作任何处理。Ⅱ组 (环磷酰胺组 ) :DA到Lewis大鼠的心脏移植前后分别经腹腔注射环磷酰胺 80mg/kg。Ⅲ组 (联体组 ) :0d :供、受者大鼠腹腔注射环磷酰胺 80mg/kg ;第6d :供、受者联体 ;第 16d :联体大鼠腹腔注射环磷酰胺80mg/kg ;第2 1d :分开联体 ,行DA到Lewis大鼠的心脏移植。观察各组移植心存活时间 ,供心病理学改变 ,供、受者间的混合淋巴细胞反应 (MLR)。结果　Ⅲ组形成了稳定的供、受者嵌合体 ,供心平均存活时间为 :(76 .33± 10 .71)d ,较Ⅰ组 (7.17± 1.17)d、Ⅱ组 (8.5 0± 1.87)d显著延长 ,差异有显著性 (P <0 .0 1) ;Ⅲ组的供心仅见少量炎性细胞浸润 ;供、受者间MLR较正常对照组显著降低 ,差异有显著性 (P <0 .0 1)。结论　联体共生可形成稳定的外周和中枢嵌合体 ,嵌合体在同种心脏移植的免疫耐受中起重要作用。     

门静脉预输注供者凋亡骨髓细胞延长大鼠移植心脏的存活时间

目的探讨门静脉输注供者的凋亡骨髓细胞对大鼠移植心脏存活时间的影响。方法以Wistar大鼠为供者、SD大鼠为受者,将其随机分为4组,每组15只,A组为对照组,受者术前6d经门静脉输注RPMI1640培养基0.5ml,术后不注射环孢素A(CsA);B组为骨髓细胞输注组,受者术前6d经门静脉输注供者的骨髓细胞5×107个,术后不用CsA;C组为凋亡细胞输注组,受者术前6d经门静脉输注供者的凋亡骨髓细胞5×107个,术后不用CsA;D组为CsA组,受者术前3d起腹腔注射CsA5mg/kg,直至术后10d。60Coγ射线照射诱导骨髓细胞凋亡,各组大鼠建立腹部异位心脏移植模型。观察各组移植心的存活时间、组织病理学改变,测定受者血清中白细胞介素10(IL-10)及转化生长因子β1(TGF-β1)的含量及单向混合淋巴细胞培养(MLR)结果。结果C组移植心的存活时间为(14.00±0.95)d,较A组明显延长(P<0.01),但仍未达到长期存活(存活时间短于CsA组)。术后7d,C组移植心组织切片呈现中度急性排斥反应,心肌细胞损害不明显,但有大量淋巴细胞浸润。除术后7d的TGF-β1外,C组其它各测定时点的血清IL-10及TGF-β1均高于其它3个组。C组大鼠的脾细胞在供鼠脾细胞的刺激下,细胞增殖反应明显低于A组、B组(P<0.01),而对第三品系大鼠的脾细胞仍有较强的增殖反应,具有明显的抗原特异性;CsA组的细胞增殖均被抑制。结论门静脉预输注供者的凋亡骨髓细胞,可明显延长大鼠移植心脏的存活时间,但单纯单剂量的输注凋亡细胞并不足以建立长期、稳定的免疫耐受。     

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.     

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.     

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.     

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.     

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.