诱导小鼠破骨前体细胞成熟分化的实验条件探讨

目的探讨小鼠单核细胞RAW264.7能否在RANKL诱导下向破骨细胞成熟分化。方法 RANKL作用RAW264.7细胞7天～9天,光镜、透射电镜、扫描电镜(scanning electron microscope,SEM)分别观察其细胞形态学变化,用抗酒石酸酸性磷酸酶(tartrate-resistant acid phosphatase,TRAP)染色法观察TRAP阳性的多核细胞,RT-PCR检测破骨细胞表型和功能基因表达变化情况,扫描电镜观察破骨细胞在骨片上形成骨吸收陷窝。结果光镜、透射电镜下可见细胞胞体增大,为椭圆形或不规则形,胞核5～10个,扫描电镜下可见细胞表面大量的伪足样突起;此外,RANKL能诱导RAW264.7细胞分化为TRAP染色阳性的多核破骨细胞,细胞多为超过5个核的多核巨细胞;RAW264.7细胞成熟分化后具有骨吸收功能,并且能上调Cathepsin-K、TRAP、RANK等典型破骨细胞表型和功能基因mRNA的表达。结论 RAW264.7细胞是一种较好的破骨前体细胞模型,单用50ng/ml的RANKL体外连续诱导7天以上,能明显促进它向成熟的破骨细胞分化。     

CTGF对破骨前体细胞RAW264.7增殖及碳酸酐酶Ⅱ分化的影响

目的研究结缔组织生长因子(CTGF)对体外培养的破骨细胞前体细胞RAW264.7增殖及对核因子Kappa B配体受体(RANKL)诱导体外培养的破骨细胞前体细胞RAW264.7分化为成熟多核破骨细胞的影响。方法使用200 ng/mLCTGF干预培养的破骨细胞前体细胞RAW264.7,采用3H-TdR掺入法检测RAW264.7细胞增殖率;使用200 ng/mL CTGF与RANKL单独或共同处理RAW264.7细胞,抗酒石酸酸性磷酸酶(TRAP)染色观察TRAP阳性多核细胞,Western blot检测碳酐酶Ⅱ蛋白的表达。结果 CTGF可显著促进RAW264.7细胞增殖;200 ng/mLCTGF与RANKL共同处理RAW264.7细胞可促进RAW264.7细胞分化为成熟多核破骨细胞;200 ng/mL CTGF与RANKL共同处理RAW264.7细胞可促进RAW264.7细胞碳酐酶Ⅱ蛋白的表达。结论 CTGF促进体外培养的破骨细胞前体细胞RAW264.7增殖,促进RANKL诱导的破骨细胞前体细胞RAW264.7分化为成熟多核破骨细胞。     

IL-6对RAW264. 7细胞成熟分化的体外实验研究

目的探讨研究白介素-6(Interleukin-6,IL-6)对核因子NF-κB受体活化因子配体(Receptor activator of nuclear kappa B ligand,RANKL)及对破骨前体细胞的成熟分化和溶骨效应。方法破骨前体细胞RAW264.7细胞经50ng/mL RANKL诱导1 d后将其分为:1、空白对照组(RANKL+PBS)2、低浓度IL-6组(RANKL+50ng/mL IL-6)3、中浓度IL-6组(RANKL+100ng/mL IL-6)4、高浓度IL-6组(RANKL+150ng/mL IL-6)。连续培养9 d后,进行HE染色检测成熟破骨细胞生成量;通过抗酒石酸酸性磷酸酶(Tartrate resistant acid phosphatase, TRAP)染色法观察TRAP阳性多核细胞的情况;运用扫描电镜检测破骨细胞在骨片上的骨吸收陷窝形成情况。结果 HE染色中,成熟破骨细胞生成量中、高浓度IL-6组明显少于低浓度IL-6组(P0.05),低浓度IL-6组和空白对照组间无明显差别(P0.05)。②通过TRAP染色后,经染色阳性区域面积与视野面积的百分比计算,中、高浓度IL-6组与明显少于低浓度和空白对照组(P0.05)。③扫描电镜观察发现骨吸收陷窝面积与视野面积的百分比随着IL-6浓度的增高,相比空白对照组有显著减少,且高浓度IL-6组中陷窝形成最少(P0.05)。结论 IL-6能直接作用于经RANKL诱导的RAW264.7细胞,能明显抑制破骨细胞激活分化,并降低破骨细胞所致的骨吸收效应。当IL-6浓度超过50ng/mL时,其抑制破骨细胞的骨吸收效应更加明显。     

不同浓度金属磨损颗粒对破骨细胞体外分化的影响

[目的]观察不同浓度金属磨损颗粒对RAW 264.7在体外分化成破骨细胞的影响,明确浓度与破骨细胞分化数量的关系.[方法]真空球磨法制备人工关节磨损颗粒:RANKL诱导RAW 264.7体外分化成破骨细胞,通过TRAP染色,电镜扫描检测骨片吸收陷窝来鉴定破骨细胞;不同浓度人工关节磨损颗粒混悬液作用RAW 264.7,并用RANKL诱导后第7 d,TRAP染色后,光镜下计数破骨细胞数量.[结果]不同浓度磨损颗粒作用于RAW 264.7 7 d后,显微镜下计数破骨细胞数量,结果显示随着磨损颗粒混悬液浓度增加,RANKL诱导生成的破骨细胞增多,低、中、高浓度3组破骨细胞数均显著高于空白对照组(P<0.05),中、高浓度组破骨细胞数均显著高于低浓组(P<0.05),高浓度组破骨细胞数亦显著高于中浓组(P<0.05).[结论](1)RAW 264.7是一种较好的破骨前体细胞模型,RAW 264.7诱导形成破骨细胞的方法简便易行,所获得破骨细胞均一性好;(2)人工关节金属磨损颗粒为RAW264.7细胞向具有骨质吸收功能的破骨细胞转化发挥正向作用,而且与混悬液的浓度有量效关系.     

RANKL诱导小鼠单核细胞RAW264.7分化成成熟破骨细胞

目的观察小鼠的单核／巨噬细胞RAW264．7的一般生物学特征及在RANKL诱导下形成成熟破骨细胞的特征。方法RANKI，诱导RAW264．7细胞6d后，用抗酒石酸酸性磷酸酶(TRAP)染色法观察TRAP阳性多核细胞，吖啶橙染色激光共聚焦显微镜(LCSM)观察多核细胞形态；诱导RAW264．7细胞9d后，RT、PCR检测RAW264．7细胞的破骨细胞表型和功能基因表达及其RANKL诱导后变化；诱导RAW264．7细胞12d后，钙磷覆盖的破骨细胞活性分析板观察破骨细胞的骨吸收功能。结果RAW264．7细胞TRAP染色阴性，单核或2个核，能表达破骨细胞表型和功能基因，无骨吸收功能。RANKL可诱导RAW264．7细胞形成TRAP阳性成熟的多核破骨细胞，上调CathepsinK、CAⅡ、integrinβ3等基因mRNA的表达。结论RAW264．7具有破骨细胞特征性基因表达谱，是一种较好的破骨前体细胞模型。RANKL可诱导RAW264．7细胞形成成熟破骨细胞。     

低分子量褐藻糖胶对破骨细胞凋亡的影响

目的探讨低分子量褐藻糖胶(LMWF)对小鼠单核细胞RAW264.7诱导成熟破骨细胞凋亡的影响。方法通过100ng/m L RANKL诱导RAW264.7细胞株分化为破骨细胞,经TRAP特异性染色和骨吸收陷窝对诱导后的细胞进行鉴定。鉴定成功后,用100 ng/m L RANKL诱导RAW264.7细胞株5 d后,使用含有LMWF的培养基继续培养3 d,通过对TRAP阳性细胞计数和分析骨吸收面积来观察低分子量褐藻糖胶对破骨细胞的抑制和骨吸收功能情况;采用流式细胞术检测LMWF对破骨细胞凋亡的影响,capsase-3活性测试试剂盒检测LMWF对capsase-3活性进行测定;RT-PCR检测LMWF对成熟破骨细胞BAX与BCL-2基因表达的影响。结果单纯采用100 ng/m L的RANKL可成功诱导成熟的、有功能的破骨细胞。LMWF可以明显抑制RANKL诱导成熟破骨细胞的形成以及成熟破骨细胞的骨吸收功能;流式细胞术显示LMWF可增加成熟破骨细胞的早期凋亡率;并且能升高capsase-3的活性;PCR显示LMWF可明显下调破骨细胞凋亡相关的BCL-2和上调BAX基因mRNA表达,降低BCL-2/BAX的比值。结论低分子量褐藻糖胶可抑制破骨细胞的活性与骨吸收能力,促进破骨细胞凋亡,其主要机制是通过下调BCL-2和上调BAX mRNA基因表达实现的。     

复合振动抑制RAW264.7细胞分化成熟

目的研究复合振动对核因子-κB受体活化因子配体(RANKL)诱导的RAW264.7细胞分化的影响,探讨复合振动对破骨细胞分化的影响及机制。方法 RAW264.7细胞RANKL诱导培养3或4d并施加复合振动干预,通过抗酒石酸酸性磷酸酶(TRAP)染色观察TRAP阳性多核细胞形成的变化,real-time RT-PCR分析破骨细胞特异性基因组织蛋白酶K(cathepsin K),金属蛋白酶-9(MMP-9)和TRAP表达的变化。结果复合振动能抑制RANKL诱导破骨细胞形成,下调破骨细胞特异基因cathepsin K,MMP-9和TRAP的表达。结论 RANKL促进RAW264.7细胞向破骨细胞分化,并增加特异基因的表达,但RANKL的促进作用受复合振动抑制。这进一步的阐释复合振动抗骨质疏松的作用机制。     

通过骨基质表面培养板检测RANKL诱导破骨细胞骨侵蚀能力

目的探讨以骨基质表面培养板替代骨磨片鉴定破骨细胞骨侵蚀能力的应用方法。方法通过RANKL诱导破骨前体细胞RAW264. 7建立破骨细胞分化模型,运用TRAP染色检测破骨细胞分化程度,并以骨基质表面培养板替代骨磨片行骨陷窝试验检测破骨细胞骨侵蚀能力,以侵蚀面积反映骨侵蚀能力。结果不同浓度的RANKL因子可有效诱导破骨前体细胞RAW264. 7分化为成熟多核破骨细胞,呈浓度依赖性。成熟破骨细胞在骨基质表面培养板上形成不同面积的不规则侵蚀圆环,趋势与破骨细胞分化程度一致。结论使用骨基质表面培养板可有效反映破骨细胞形成及骨侵蚀能力,与TRAP染色结果一致,并且具有操作简便、结果直观、便于统计分析等优点。     

高糖及TNF-α对RAW264.7细胞向破骨细胞分化的影响

【摘要】 目的 观察高糖及TNF-α的培养条件对RAW264.7细胞向破骨细胞诱导分化的影响。方法 在正常、高糖(30 mmol/L)及TNF-α(10 μmol/L)条件下培养RAW264.7细胞后,加入浓度为100 ng/mL的细胞核转录因子κB受体激活物的配体(receptor activator of NF-κB ligand, RANKL)为诱导剂,诱导RAW264.7向破骨细胞分化;诱导9天后,抗酒石酸酸性磷酸酶(TRAP)染色,比较各组TRAP+细胞数,RT-PCR及Western Blot检测各组破骨细胞标志基因CTR和MMP-9的表达。结果 不同的培养条件下RANKL均能诱导RAW264.7分化为成熟的破骨细胞,其中TNF-α环境中RAW264.7形成的TRAP+阳性细胞数、CTR和MMP-9的表达最高,而在高糖环境下最低。结论 TNF-α可以促进RAW264.7向破骨细胞分化,而高糖对这个过程可能是抑制作用,这一现象符合Ⅰ型和Ⅱ糖尿病患者骨质破坏的表现;高糖及TNF-α的培养条件下RANKL对RAW264.7的作用可模拟糖尿病足病变微环境中OC的诱导分化的过程。     

不同氧环境中破骨细胞的发育分化和功能变化研究

目的 本实验拟观察不同氧浓度下破骨细胞诱导过程中的分化发育,寻找破骨细胞体外培养的适宜氧浓度,为骨转换平衡的修复提供依据.方法 取野生型C57B/L小鼠(2个月龄左右,雄性)骨髓进行破骨细胞的诱导培养.用RANKL(10ng/ml)和M-CSF(10ng/ml)联合的诱导方案,将小鼠骨髓中单核-巨噬细胞系体外诱导为破骨细胞样细胞.将原代破骨细胞置于20%O2、7%O2、2%O2下诱导培养,MOCP5不同氧浓度下普通培养.用MTT法检测MOCP5的增殖变化,用抗酒石酸酸性磷酸酶(TRAP)染色检测破骨细胞形成的变化,并进行TRAP阳性细胞计数,用象牙骨片骨吸收陷窝甲苯胺蓝染色检测破骨细胞骨吸收活性的变化.结果 骨髓中单核-巨噬细胞体外经RANKL和M-CSF联合诱导可分化为多核的破骨细胞样细胞,在诱导第3天细胞开始融合,第5天TRAP染色强阳性,第8天可见象牙骨片上形成圆形、椭圆形、腊肠形等多种形态的骨吸收陷窝.MTT检测显示MOCP5在20%O2培养时一直处于增殖状态,7%O2条件下由增殖期进入平台期,2%O2时增殖缓慢且没有规律.20%O2、7%O2、2%O2培养下形成的TRAP阳性破骨细胞数分别为22±5.97、34±2.97、7±1.39(P<0.05),原代诱导的破骨细胞在20%O2、7%O2、2%O2形成的骨吸收陷窝面积(μm2)分别为3892.28±1642.78、5356.7±1655.6、2573±994.48(P<0.05).结论 体外RANKL和M-CSF联合可将骨髓单核-巨噬细胞诱导成多核的破骨细胞样细胞作为破骨细胞的研究模型.常氧条件下破骨细胞的TRAP阳性细胞数和骨吸收活性均低于7%O2.7%O2培养下的破骨细胞更接近于体内生理状态的破骨细胞.     

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.     

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.