椎体骨折评估在绝经后女性骨质疏松诊断中的应用价值

目的研究利用双能X线骨密度仪扫描的脊柱影像进行椎体骨折评估在绝经后女性骨质疏松诊断中的应用价值。方法回顾499名年龄≥50岁的绝经后女性行骨密度检测同时行椎体侧位扫描,分析骨密度及椎体骨折评估(vertebral fracture assessment,VFA)的检测结果,收集研究对象的一般资料。结果对499名绝经后女性进行VFA检测结果分析:(1)椎体骨折诊断率提高了41.1%,骨质疏松诊断率提高了6.3%,严重骨质疏松诊断率提高了29.1%(P0.05);(2)当骨密度达到骨质疏松阈值时,椎体骨折率明显升高,较骨密度未达到骨质疏松阈值的椎体骨折发生率提高了29.2%(P0.05);(3)年龄增加、绝经年限延长的女性椎体骨折、骨质疏松、严重骨质疏松的患病率显著增加,骨量显著减少(P0.05);此外,体质量指数(body mass index,BMI)降低的绝经后女性骨量显著减少,骨质疏松的患病率显著增加(P0.05)。结论骨密度检测联合椎体骨折评估可以显著提高椎体骨折、骨质疏松、严重骨质疏松的诊断率;骨密度越低,年龄越大,绝经年限越长,椎体骨折的风险就越高;随年龄增长、绝经年限增加、BMI降低,骨密度减少,骨质疏松患病率增加。     

定量与半定量方法评估DXA影像发现椎体骨折的比较

目的比较形态学定量评估方法和Genant半定量方法对DXA影像进行椎体骨折评估的一致性。方法对217例≥50岁绝经后女性作骨密度检测的同时进行胸腰椎T4~L5正侧位扫描,采用形态学定量评估方法和Genant半定量方法进行椎体骨折评估,比较二种方法确定椎体骨折的一致性和二种方法确定椎体骨折组与无椎体骨折组的临床特征。结果形态学定量评估方法确定59例椎体骨折,椎体骨折率为27.19%;Genant半定量方法确定60例椎体骨折,椎体骨折率为27.65%。kappa一致性分析,κ=0.80。二种方法确定椎体骨折组与无椎体骨折组的临床特征无统计学差异。结论 Genant半定量方法和形态学定量评估方法均是评估椎体骨折的有效方法。     

绝经后医务人员骨密度与椎体骨折的横向研究

目的通过横向研究探讨绝经后医务人员骨密度与椎体骨折的相互关系。方法从单中心医务人员中,随机抽取216名绝经后女性,通过双能X线吸光测定仪检测其骨密度,运用Genant半定量法评估椎体骨折,分析骨密度与骨质疏松性骨折、椎体骨折的畸形程度以及EQ-5D评分的关系。结果绝经后医务人员椎体骨密度的正常组、骨量减少组及骨质疏松组分别占27%、35%、38%;随着骨密度T值的降低,正常组(T≥-1. 0)、骨量减少组(-2. 5T-1. 0)和骨质疏松组(T≤-2. 5)的椎体骨质疏松性骨折患病率明显升高(P0. 05),分别为28%、42%和53%;椎体骨折组(无论有/无临床症状)的骨密度明显低于无骨折组(P0. 01);椎体骨折畸形程度越重,其骨密度越低(P0. 01),躯体伸展程度、日常活动、疼痛或舒适度的EQ-5D评分亦越低(P0. 05)。结论绝经后医务人员随着骨密度的降低,骨质疏松和椎体骨折的患病率增加,生活质量亦降低。     

冀东油田健康体检中老年骨密度水平现状调查

目的：了解冀东油田中老年人群骨密度（BMD）水平,为防治骨质疏松症（OP）提供依据。方法应用美国GE Achilles Express骨密度仪,进行右跟骨定量超声测定,以骨密度T值≤－2．5诊断骨质疏松（ OP）,－2．5＜T值≤－1诊断骨量减少（ OPA）,两者统称骨密度异常,作为标准尺度进行分析,收集2012年3月至2012年7月参加体检40岁以上人群的骨密度。结果入选3596例中老年人,OP患病率6．34％,OPA患病率25．22％,男性OP患病率7．47％,OPA患病率31．41％;女性OP患病率5．2％,OPA患病率18．96％。按年龄分段：40－49岁、50－59岁、60－69岁、70－80岁段各年龄段,男性OP患病率分别为5．31％,7．31％、9．95％、11．59％,随年龄增长而增加,OPA患病率32．78％、31．25％、29．70％、33．33％,呈“U”型改变;女性OP患病率分别为1．26％、3．68％、11．63％、24．39％,随年龄而增加, OPA 患病率分别为11．73％、17．99％、31．19％、14．63％,呈“∩”型改变。按性别分层：40－59岁骨密度异常（ OP、OPA）男性大女性,60－80岁骨质疏松女性大于男性。结论随年龄增长骨密度异常比率增加,骨质疏松患病率表现明显,女性更为明显,要加强防治;40－59岁的男性骨密度异常明显高于女性,更应该重视,改变不良的生活习惯,参加体育锻炼。     

绝经后女性腰椎T值评分与椎体骨折的关系

目的探讨绝经后女性腰椎骨密度的T值评分与发生椎体骨折的关系。方法选择原发性骨质疏松症女性患者共74例,其中发生椎体骨折患者37例,无椎体骨折患者37例,所有受检者均行正侧位胸腰椎X线摄片证实。两组女性的出生年月、身高、体重、绝经年限等无显著性差异。用双能X线吸收仪(DXA)分别检测正位腰椎(L1-L4)及一侧股骨近段股骨颈的骨密度(BMD)值及T值,统计腰椎部位的T值评分(T-Score),以腰椎T值评分达≤-2.5可入选,并对两组腰椎的T值评分进行统计分析。结果骨折组腰椎T值评分明显低于非骨折组腰椎T值评分(P0.05)。结论绝经后女性发生椎体压缩性骨折与腰椎骨密度的T值评分降低相关。     

绝经后2型糖尿病患者不同部位骨密度的 变化情况及影响因素

目的探讨绝经后2型糖尿病女性不同部位骨密度的变化、影响因素及骨质疏松诊断率,为早期诊断、早期防治糖尿病并发骨质疏松提供理论依据。方法回顾性分析在我院内分泌科住院的绝经后2型糖尿病患者169例,采用双能X线骨密度测量仪检测腰椎1-4椎体、左侧股骨颈、Ward’s三角及全髋的骨密度,统计各年龄组不同部位的骨密度值及T≤-2.5SD所占百分比,采用多元逐步回归分析各部位骨密度影响因素。结果各部位骨密度随着年龄的增长而下降,股骨颈及Ward’s三角、全髋部位的骨密度下降幅度较大,腰椎部位骨密度下降相对平缓。随着年龄增长,腰椎和髋部骨质疏松检出率增加。其中在50～59岁年龄组中,骨质疏松检出率最高的部位是L1-L4正位,在60岁以上的年龄组中检出率最高的部位是Ward’s三角。多元回归分析结果显示L1、L2、L3、L4、股骨颈、Ward’s三角及全髋部位骨密度均与BMI呈正相关,除L3、L4外,所有部位骨密度与年龄呈负相关,L3、L4部位骨密度与绝经年限及空腹C肽有关。各部位骨密度与空腹血糖、HbA1C未见相关性。结论随年龄的增长,绝经后糖尿病患者骨质疏松症检出率随测量部位不同而不同。腰椎正位(L1-L4正位)和Ward’s三角分别是50～59岁及60岁以上女性诊断骨质疏松最敏感的部位。影响绝经后2型糖尿病患者骨密度的主要因素为年龄、BMI。低体重、高龄的糖尿病女性因定期检查骨密度预防骨质疏松骨折的发生。     

胸腰段椎体CT值对骨质疏松骨折预测意义

[目的]探讨常规CT测得胸腰段椎体CT值随年龄的变化趋势及其在骨质疏松骨折中的预测意义。[方法]对150例骨质正常人测量T11～L2椎体CT值并进行线性回归分析,研究随年龄增长胸腰段椎体CT值的变化趋势。比较289例骨质疏松骨折(osteoporotic fracture, OF)患者与123例骨质疏松无骨折(osteoporosis, OP)患者不同年龄段椎体CT值,并绘制相应的ROC曲线。[结果]随着年龄增长,正常人T11～L2椎体CT值均呈下降趋势。在女性50～59、60～69年龄段组,男性50～59、60～69、70～79三个年龄段,OF组T12椎体CT值均显著低于OP组(P0.05)。T11椎体CT值在60～69岁女性中诊断骨折效能较高,临界值为112.40 HU,曲线下面积(AUC)为0.74。T12椎体CT值在男性70～79岁诊断骨折效能最高,临界值为123.30HU,AUC为0.93。[结论]随年龄增长,胸腰段椎体中女性、男性椎体下降最快的椎体分别为T11、T12;常规CT所测得椎体CT值能为临床预测骨质疏松骨折提供一定的参考价值。     

绝经后妇女椎体骨折与骨密度的对照研究

目的探讨绝经后妇女骨质疏松性椎体骨折与骨密度的关系。方法随机选择椎体骨折的绝经后妇女120例为骨折组，无椎体骨折的120例绝经后妇女为对照组。两组的年龄、身高、体重等差异无显著性，均行胸腰椎正侧位X线摄片。用双能X线吸收仪（DXA）测量腰椎（L2-4）前后位及髋部骨密度（BMD）和T值。结果骨折组腰椎及髋部BMD和T值均低于对照组（P≤0．05）。结论腰椎BMD降低与绝经后妇女的骨质疏松性椎体骨折相关，髋部骨密度值的降低在一定程度上也能提示骨折的危险性。绝经后骨质疏松妇女应重视BMD变化，预防椎体骨折的发生。     

济南市1116例中老年人跟骨骨密度分析

目的探讨济南市中老年人骨质疏松的患病情况，为老年病工作者和老年人群的骨保健提供资料。方法对1116例中老年人健康查体者应用单能X线骨密度仪测量的右跟骨骨密度资料进行了回顾性分析，比较了骨密度与年龄和性别的关系。结果①在男性和女性45岁以上的人群中，随着年龄的增大，T值和BMD均逐渐降低，女性的降低幅度明显高于男性（P〈0．05）。②骨量减少和骨质疏松者在60岁以上男性中占60％，75岁以上占70％；骨质疏松患病率男性65岁～69岁组约占5％，70岁～74岁组约占10％，大于75岁组在20％以上。45岁～49岁的女性有30％的骨量减少；骨量减少和骨质疏松在女性50岁～54岁约占45％，55岁～59岁约占80％，60岁～69岁约占90％，70岁以上者高达99％。骨质疏松患病率在女性50岁～54岁近10％，55岁～59岁近30％，60岁～64岁近40％，65岁～69岁50％以上，70岁以上在70％以上。女性的骨质疏松患病率明显高于男性（P〈0．01）。③骨密度测定结果与年龄的相关性分析也显示，T值和BMD与年龄呈显著的负相关（P〈0．05），在女性其相关性更强。④以年龄为自变量，以T值和BMD为应变量，进行曲线拟合也看出，无论在男性还是在女性，T值和BMD随年龄的增大而逐渐变小，在女性曲线更陡。结论在中老年人群，随着年龄的增大，骨密度逐渐降低，骨质疏松的患病率明显增加，尤其在女性更为明显。     

绝经后妇女骨质疏松性椎体骨折与腰椎骨密度的关系

目的探讨绝经后妇女骨质疏松性椎体骨折与腰椎骨密度的关系。方法选择骨质疏松性椎体骨折的绝经后妇女23例为骨折组,无椎体骨折的25例绝经后骨质疏松妇女为对照组。两组的年龄、绝经年限、身高、体重、体重指数差异无显著性,均行胸腰椎正侧位X线摄片。用双能X线吸收仪（DXA）测量的腰椎（L2-4）前后位骨密度（BMD）、骨矿含量（BMC）和T值。结果骨折组BMD、BMC和T值均低于对照组（P〈0.01）。结论腰椎BMD降低与绝经后妇女的骨质疏松性椎体骨折相关。绝经后骨质疏松妇女应重视BMD变化,预防椎体骨折的发生。     

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.     

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.