麝香对颅骨骨缺损模型大鼠基质细胞衍生因子1和肝细胞生长因子的相关性研究

目的探讨麝香对颅骨骨缺损模型大鼠基质细胞衍生因子1(stromal cell-derived factor 1,SDF-1)和肝细胞生长因子(hepatocyte growth factor,HGF)水平变化的影响及其作用机制。方法 SD大鼠雌、雄各150只,利用牙科钻建立颅骨骨缺损模型,模型动物完全随机分为给药组和模型组,又将这两组分别分为3小组,每组50只。给药组灌服麝香,模型组灌服生理盐水,采用酶联免疫吸附法(ELISA)分别测定各组7d、14d、28d血清中SDF-1、HGF的变化,将所得OD值处理计算后应用SPSS17.0统计分析。结果与模型组比较,给药组第7天SDF-1含量增加,差异有统计学意义(P=0.0008),第7天和第14天HGF含量均增加(P=0.0158,P=0.0234),但第7天表达增加更加显著。结论麝香可促进大鼠颅骨骨缺损区的愈合速度,而这种愈合机制可能与增加血清中SDF-1、HGF水平有关。     

麝香对颅骨骨缺损模型大鼠SCF和MCP-1 mRNA表达的影响及意义

目的分析干细胞因子(SCF)、单核细胞趋化蛋白1(MCP-1)在颅骨骨缺损模型大鼠中的作用及麝香对二者表达的影响。方法通过颅骨钻建立颅骨骨缺损模型,将模型大鼠随机分为给药组与模型组,再将给药组和模型组随机分为3小组,给药组灌服麝香,模型组灌服生理盐水,分别在干预后7 d、14 d、28 d通过酶联免疫吸附法(ELISA)检测各组大鼠血清中SCF表达及采用实时荧光定量PCR法检测颅骨骨缺损处MCP-1 mRNA含量的表达变化。结果与模型组比较,给药组第14天SCF表达最低,且无显著性,第7天和第28天其表达均比第14天升高,这两时间段与模型组比较差异均有统计学意义(P=0.0002、0.0025),但是第7天SCF表达增加更加显著;给药组在第7天MCP-1 mRNA表达水平最高,与模型组比较差异有统计学意义(P0.05),第14天和第28天其表达持续降低,与模型组比较差异均无统计学意义(P=0.0633、0.1597)。结论SCF、MCP-1在颅骨骨缺损修复愈合过程中可能起重要作用,麝香通过增加模型大鼠血清中SCF的表达和颅骨骨缺损组织MCP-1 mRNA的表达,间接反映出骨缺损修复愈合机制可能与增加SCF和MCP-1 mRNA表达有关,麝香在加速骨缺损修复与愈合微环境中起着重要作用。     

Brdu标记的rBMSCs在大鼠体内的迁移

目的5-溴-2-脱氧尿嘧啶核苷(5-bromo-2-deoxyuridine，Brdu)体外标记大鼠骨髓间充质干细胞（rBMSCs)，通过尾静脉回植于大鼠体内，观察其是否在大鼠体内能向损伤部位迁移。方法 采用贴壁筛选法培养rBMSCs，对rBMSCs进行鉴定，用Brdu标记细胞并计算标记率;大鼠颅骨骨缺损模型的建立;Brdu标记的rBMSCs体内回植;分别于7、14、21d后处死大鼠取出损伤部位的颅骨，并对其脱钙、制作切片;做荧光免疫组化染色;用荧光倒置相差显微镜来观察标本处是否有Brdu标记的rBMSCs。结果 筛选纯化的骨髓间充质干细胞呈均一的成纤维细胞样，贴壁生长，以长梭形为主，漩涡状盘旋排列，CD45阴性表达，CD44、CD90表达阳性，rBMSCs经诱导后可向成脂、成骨分化。Brdu标记率为86. 2%，在标本处检测到Brdu标记的 rBMSCs，14d迁移效果最佳。结论 Brdu标记的rBMSCs可以进行大鼠体内的迁移研究。     

Hoechst33342标记大鼠骨髓间充质干细胞及其在大鼠体内的迁移

目的 检测外源性的BMSCs是否可向骨缺损处迁移,Hoechest3342标记BMSCs,从而跟踪外源性BMSCs在体内的迁移,研究其归巢机制可行性.方法 贴壁筛选提取大鼠BMSCs,培养至第三代,用Hoechst33342标记后,尾静脉回植于颅骨缺损的大鼠体内,14d后处死大鼠,取颅骨,切片,荧光显微镜下观察细胞迁移情况.主要观察指标:光学显微镜下观察不同时期细胞形态和表面抗原检测;荧光显微镜下观察Hoechst33342标记后细胞形态,以及细胞增殖率;组织切片上Hoechst33342标记的阳性细胞.结果 筛选纯化的BMSCs呈均一的成纤维细胞样,贴壁生长,以长梭形为主.CD45阴性,CD44、CD90均呈阳性表达;组织切片上可见Hoechst33342标记大鼠的BMSCs.结论 外源性的BMSCs可向骨缺损处迁移;Hoechst33342可以标记BMSCs,从而跟踪外源性BMSCs在体内的迁移,进而研究其归巢机制.     

麝香对骨缺损模型大鼠HMGB1和BMP2表达的影响

目的探讨麝香对高迁移率族蛋白1(highmobilitygroupbox-1protein,HMGB1)和骨形态发生蛋白2(bone morphogenetic protein-2,BMP2)在颅骨骨缺损模型大鼠组织中表达的变化。方法 SD大鼠300只,建立颅骨骨缺损模型。随机分为对照组和给药组,每组150只,再将这两个组按照第7、14和28天分为3个小组,每组50只。给药组按42 mg/kg给予天然麝香灌胃,对照组灌服等体积的生理盐水,均每日1次。第7、14和28天采用蛋白印迹法检测HMGB1和BMP2的表达。结果给药组HMGB1、BMP2在第7天的表达均达到峰值(P0.05),第14天时降低,第28天时表达最低;与对照组比较,第7天HMGB1、BMP2表达均有统计学意义(P0.05);给药组第7和14天HMGB1的表达明显高于本组第28天(P0.05)。结论麝香促进大鼠HMGB1、BMP2的表达增加,可能是颅骨骨缺损处的愈合原因之一。     

不同浓度麝香含药血清对骨髓间充质干细胞迁移影响的实验研究

目的探讨麝香对外源性骨髓间充质干细胞(bone marrow mesenchymal stem cells,BMSCs)增殖和迁移的影响。方法将60只SD大鼠随机分为麝香高、中、低剂量组及空白对照组,制备麝香含药血清及生理盐水血清。15只SD大鼠利用全骨髓贴壁法分离BMSCs,培养至P3代,通过形态学观察、表型鉴定、成骨成脂诱导鉴定BMSCs,鉴定认为培养成功后通过麝香含药血清干预BMSCs,检测细胞增殖率,利用Transwell实验检测麝香含药血清对BMSCs迁移的影响。结果外源性大鼠BMSCs呈梭形贴壁生长,生长状态良好;表型鉴定:CD45、CD34阴性表达,CD44、CD90阳性表达;细胞成骨、成脂诱导后可定向成骨、成脂分化;不同浓度麝香组与对照组比较均能提高BMSCs增殖率(P0.05);与对照组比较,不同浓度麝香在24 h、48 h、72 h均增加BMSCs迁移(P0.05),以低浓度组效果最佳。结论麝香含药血清可以促进BMSCs增殖,促进BMSCs的体外迁移。     

SDF-1/CXCR4介导体外冲击波促进大鼠骨髓间充质干细胞的黏附、迁移作用

目的探讨体外冲击波(extracorporeal shock wave,ESW)对大鼠骨间充质干细胞(marrow mesenchymal stem cells,MSCs)黏附、迁移及成骨分化的影响及SDF-1/CXCR4通路在其中的作用。方法体外试验分四组:空白对照组(Ctrl组)、冲击波组(ESW组)及CXCR4特异性抑制剂AMD3100对照组(AMD组),采用最适宜能力ESW(500脉冲次数、10 kV)处理MSCs,通过黏附率、划痕试验、Transwell试验对比MSCs黏附及迁移能力的差别,通过ELISA检测SDF-1分泌表达及蛋白免疫印迹法检测CXCR4的表达,研究SDF-1/CXCR4通路的作用;体内试验则选取12周龄SD大鼠48只,随机分成Ctrl、ESW及AMD 3组各16只,采用右侧股骨中段骨缺损模型,各组骨缺损处植入载有该组细胞的PLGA支架,AMD组术后接受AMD3100注射(1 mg/kg/day),于术后第4、8周取材,通过HE染色评估骨缺损区域的骨愈合及新生骨形成情况。结果 ESW明显增加了MSCs的SDF-1分泌量及CXCR4受体表达,促进了MSCs的黏附、迁移及骨缺损的愈合,AMD3100可部分抑制ESW此促进作用。结论 ESW可促进MSCs的黏附、迁移能力,并促进骨缺损区域的骨愈合,其分子机制与分泌型蛋白SDF-1及其受体CXCR4的表达相关,此结果为ESW在促进骨愈合治疗中的临床应用提供了理论基础。     

股密葆方对大鼠激素性股骨头坏死血管修复影响的实验研究

目的 探讨股密葆方对大鼠激素性股骨头坏死的血管生成修复的影响,以揭示其作用的部分机制。方法 176只动物随机分为空白对照组、模型组、股密葆方高、中、低剂量组,共5组,每组8只,雌雄各半。后四组参照S. Okazaki等人应用大肠杆菌内毒素联合激素注射的造模方法构建大鼠激素性股骨头坏死模型。造模成功后,股密葆方高、中、低剂量组分别灌服股密葆混悬液,空白对照组和模型组均灌服等量的生理盐水。分别选取药物干预后4周、8周、12周3个时间点,每组随机处死4只大鼠行VEGF免疫组化染色、透射电镜观察。分析每组各时间点相关指标的变化情况及各组之间的差异。结果 HE染色及透射电镜观察证实股骨头坏死动物模型建立成功,股密葆方各组VEGF表达增强,逐渐恢复至正常水平,与模组比较,差别具有统计学意义（P<0.05）,其中以股密葆方低剂量组表达最强。结论 股密葆方可以加速股骨头内的正常修复速度,促进新生血管生成,使骨形成加快。     

菟丝子黄酮对少弱精子症大鼠睾丸GM-CSF表达的影响

目的:探究菟丝子黄酮对少弱精子症大鼠睾丸GM-CSF表达的影响。方法:SD雄性大鼠30只,随机分为空白对照组、模型组和菟丝子黄酮组,每组各10只,菟丝子黄酮组和模型组腹腔注射环磷酰胺,建立少弱精子症模型。菟丝子黄酮组灌服菟丝子黄酮混悬液,空白对照组和模型组灌服等量生理盐水,连续4周。取附睾液进行精子计数及活动率测定,制作睾丸切片并分别在光镜和电镜下观察睾丸组织学变化及超微结构改变。用蛋白芯片检测各组大鼠睾丸GM-CSF的表达情况。结果:模型组大鼠与空白对照组、菟丝子黄酮组大鼠相比,附睾液精子数目降低(P0.01)且活动率下降(P0.01),睾丸形态学发生明显改变,生精小管变形,生精细胞数目减少且排列混乱。菟丝子黄酮组大鼠的睾丸组织结构正常,精子数目、活动率与空白对照组的差异无统计学意义。菟丝子黄酮组和空白对照组大鼠睾丸GM-CSF的表达量均低于蛋白芯片可测得的最小值故而未测得准确数值,模型组大鼠睾丸GM-CSF表达显著上升。结论:环磷酰胺所致少弱精子症大鼠睾丸GM-CSF表达增强,经过菟丝子黄酮干预后GM-CSF表达与空白对照组的差异无统计学意义。     

SDF-1/CXCR4信号轴调控骨髓间充质干细胞向哮喘小鼠肺组织的迁移

目的：探讨基质细胞衍生因子-1（SDF-1）/CXCR4轴在外源性骨髓间充质干细胞（MSC）向哮喘模型小鼠肺组织迁移的作用.方法：无菌条件下取GFP转基因小鼠骨髓MSC,体外扩增,鉴定.采用Transwell培养系统,观察0、50、100、150和200 ng/ml SDF-1和CXCR4阻断剂AMD3100对MSC体外定向迁移的影响.取60只雌性BALB/c小鼠,随机分为6组（n=10）：PBS非哮喘组、MSC非哮喘组、PBS哮喘组、MSC哮喘组、SDF-1处理哮喘组、AMD3100处理哮喘组.哮喘组采用哮喘致敏液0.2 ml（含100 μg卵白蛋白）致敏,并使用卵白蛋白雾化吸入激发哮喘.非哮喘组在致敏和激发时均予以PBS处理.MSC处理组于哮喘激发前移植外源性MSC.SDF-1处理哮喘组在MSC移植前气管内注入SDF-1,AMD3100处理哮喘组注入AMD3100预先孵育的MSC.PBS哮喘组注射等量的PBS液.采用Westernablot和RT-PCR方法检测肺组织中SDF-1的表达水平,通过荧光显微镜观察表达GFP的外源性MSC在哮喘小鼠肺组织中的分布情况,比较SDF-1和CXCR4阻断剂AMD3100干预对MSC向肺组织迁移的影响.结果：Transwell实验显示MSC的迁移水平与SDF-1（0~150军ng/ml）成浓度依赖性.与正常小鼠比较,哮喘小鼠肺组织SDF-1表达增强.与MSC非哮喘组比较,MSC哮喘组小鼠肺部有更多MSC聚集.在哮喘肺组织中增加外源性SDF-1能够促进MSC向肺组织迁移.通过AMD3100阻断MSC的CXCR4可以明显减少MSC向肺组织的迁移水平.结论：SDF-1/CXCR4轴参与了MSC迁移到哮喘小鼠肺组织的过程.     

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.