类风湿关节炎合并骨质疏松与7关节超声评分相关性及预测模型

目的 探讨类风湿关节炎（rheumatoid arthritis,RA）合并骨质疏松与7关节超声评分（7-joint ultrasound score ,US7）相关性并建立骨质疏松预测模型。方法 123例RA患者根据骨密度检测结果分为骨质疏松组、低骨量组和骨量正常组,进行病史记录、血清学检测、US7超声评分,通过多元logistic回归分析建立预测模型。结果 多元Logistic回归分析显示：年龄、病程、DAS28、抗环瓜氨酸抗体（CCP）是骨质疏松组与骨量正常组、低骨量组与骨量正常组的危险因子（P<0.001）。预测模型总符合率78.0 %,骨质疏松模型符合率87.5 %、低骨量模型53.3 %、正常模型82.8 %。结论 年龄、病程、DAS28、CCP是RA患者骨量异常的危险因子,建立的骨质疏松模型可为预测RA患者骨质疏松提供重要参考。     

类风湿关节炎骨质疏松危险因素分析

目的类风湿关节炎(RA)是继发性骨质疏松的常见原因,本研究旨在通过分析比较RA患者血清类风湿因子(RF)、抗环瓜氨酸多肽抗体(anti-CCP)、C-反应蛋白(CRP)、血细胞沉降率(ESR)及骨代谢六项指标水平,探讨RA患者骨质疏松的危险因素。方法 133例RA患者根据双能X线检测的骨密度(BMD)结果分为骨质疏松组、骨量减低组和骨量正常组,检测各组受试者RF、anti-CCP、CRP、ESR及骨代谢六项等指标,分析比较各组受试者各指标水平差异,并比较各组患者糖皮质激素用药情况,多元logistic回归分析上述指标与RA患者骨质疏松的关系。结果①RA患者血清RF、anti-CCP、CRP及ESR水平相较于正常人群显著升高;②骨质疏松和骨量减低组CRP、ESR及骨碱性磷酸酶(BALP)、β胶原特殊序列(β-CTx)两项骨代谢指标水平较RA骨量正常组显著升高,且OP组糖皮质激素使用率明显高于骨量正常组,差异有统计学意义;③患者年龄、病程、疾病活动度及使用糖皮质激素是RA患者发生骨质疏松的独立危险因素OR(95%CI)分别为1.116(1.013-1.230)、1.775(1.191-2.645)、4.356(1.741-10.898)和9.448(1.040-85.802)。结论 RA患者血清自身抗体、炎症指标及骨代谢指标水平存在不同程度异常,患者年龄、病程、疾病活动度及糖皮质激素使用情况可作为判断RA患者骨质疏松风险的参考指标,有助于指导临床对RA患者疾病发展和病程进行监测,并进行及时的合理治疗。     

类风湿性关节炎患者骨密度及骨代谢生化标志物的变化

目的 通过测定骨密度和骨代谢指标了解类风湿关节炎(RA)患者骨质疏松的发生情况、骨代谢指标的变化及其影响因素。方法 应用双能X线吸收法（DXA)测定110例（男28例,女82例）RA患者和120例（男30例,女90例）正常人腰椎 L1-4和股骨近端骨密度,骨代谢指标血清I型胶原氨基末端肽(NTX - 1)、骨碱性磷酸酶（B-ALP)及相关临床指标。结果 RA组男性、绝经前及绝经后女性各组腰椎骨密度均较对照组减低（P <0. 05),以绝经后女性下降显著（P < 0. 01); RA骨质疏松组患者(26例,23. 6%)股骨颈骨密度值与病程、关节肿胀数、关节压痛数、ESR、CRP、X线分期负相关(P <0. 05),与RF无明显相关性(P >0. 05)。NTX - 1水平在RA患者骨量正常组、骨量减少组、骨质疏松组依次升高,且组间两两比较差异有显著性(P < 0. 05);与骨质疏松组比较,骨量正常组和骨量减少组的ESR、CRP水平显著降低（P < 0. 05),B-ALP显著增加（P < 0.05),而这两组间的B-ALP、ESR、CRP水平差异无显著性（P >0.05)。RA患者NTX-1与CRP水平呈正相关（P <0.05)。 结论 RA继发骨质疏松十分常见,骨代谢指标NTX - 1及B-ALP测定可作为早期活动性指标。     

女性类风湿关节炎患者骨密度的研究

目的探讨女性类风湿关节炎(RA)患者骨密度(BMD)的变化和骨质疏松(OP)的发生情况及其与临床指标的相关性.方法采用双能X线骨密度仪,测量了45例女性RA患者和45例女性正常人的前臂、腰椎2～4以及股骨颈、Ward区和大转子的骨矿含量,并同时测定握力、关节功能、X线分期、关节压痛数和肿胀数、日常生活能力评估(以健康评估表HAQ积分表示)和血沉、血清类风湿因子、C反应蛋白、钙、磷、碱性磷酸酶等指标.结果女性RA患者中除股骨Ward区骨量丢失较对照组差异有显著性(P＜0.05)外,其余各测定部位的BMD与对照组间差异无显著性(P＞0.05).45例女性RA患者中发生骨质疏松较非骨质疏松组年龄更大(P＜0.005),关节功能更差(P＜0.01),HAQ积分更高(P＜0.05),握力更低(P＜0.05),CRP更高(P＜0.05).女性RA患者中服用糖皮质激素组与未服用糖皮质激素组间BMD及OP发生情况的差异无显著性(P＞0.05).绝经后女性RA患者的骨量丢失较绝经前明显(P＜0.05);除桡骨远端外,绝经后患者各测定部位BMD均低于绝经前患者(P＜0.05).Logistic Regression分析显示年龄:OR=1.085[(1.019-1.156),P=0.011]和关节功能:OR=4.828[(1.368-17.039),P=0.014]为RA患者骨质疏松发生的相关因素.结论女性RA患者的总体骨量变化与正常人相近,但股骨Ward区的骨量丢失明显高于正常人.其BMD的降低和OP的发生与年龄、绝经和关节炎的严重程度有关.     

RA患者肌肉含量与骨量变化的相关性分析

目的分析类风湿关节炎(rheumatoid arthritis,RA)患者的肌肉含量与其骨量变化特点的相关性,以及影响RA患者肌肉含量减少的相关因素。方法选取66名(男∶女=8∶25) RA患者为研究对象,平均年龄为60. 4岁。采用双能X线骨密度仪(dual energy X-ray absorptiometry,DXA)及法国MEDI-LINK超声骨密度仪对研究对象进行二维骨密度(bone mineral density,BMD)、3D体积骨密度(皮质骨、骨小梁及总体积骨密度)及肌肉含量的测定,根据T值将研究对象分为骨量正常组(41名)和骨量流失组(25名),并收集患者的一般资料和临床数据,包括性别、年龄、骨折史、吸烟史、糖尿病史、肾病史、甲状腺病史以及RA疾病活动度DSA28评分。结果与RA骨量正常组患者相比,RA骨量流失组患者的全身各部位的肌肉含量均明显降低(P0. 05); RA患者肌肉含量的减少与其BMD及总的体积骨密度的减低具有明显相关性(r=0. 342,P=0. 005及B=35022. 918,P0. 001);而RA患者的总体肌肉含量与激素的使用及RA疾病活动度(DSA28)无明显相关性。结论 RA合并骨量流失患者的肌肉含量明显减少,肌肉含量的改变与骨密度存在一定的相关性。     

OPG/RANKL系统在类风湿关节炎中的变化及其对骨质疏松的影响

目的 探讨类风湿关节炎(RA)患者外周血核因子κB受体活化因子配体(RANKL)和护骨素(OPG)水平的变化及其对RA患者骨质疏松的影响.方法 采用ELISA测定64例RA患者和60例正常人外周血中RANKL和OPG水平,采用双能X线骨密度吸收仪测定骨密度,分析RA患者中RANKL和OPG水平的变化与RA患者骨密度、骨质疏松发生之间的相关性.结果 ①和正常组相比,RA组外周血OPG水矫飨越档停琑ANKL水平明显升高,OPG/RANKL比值明显降低(P<0.0001).②RA患者各测定部位的骨密度均明显低于正常组(P<0.0001),其骨质疏松症发生率为35.9%,明显高于正常组中的15.0%(P<0.0001).③RA患者外周血OPG水平与年龄呈负直线相关(P<0.0001),与各测定部位骨密度呈正直线相关(P<0.05～0.0001).RA患者外周血RANKL水平与年龄呈正直线相关(P<0.0001),与各测定部位骨密度呈负直线相关(P<0.05～0.0001).RA患者外周血OPG/RANKL水平与关节肿胀指数、关节压痛指数、HAQ积分呈正直线相关(P<0.05～0.001),与骨密度无相关(P>0.05).④Logistic Regression多元回归法分析显示:外周血RANKL水平为RA患者中骨质疏松发生的独立的、强烈的危险因素,OR=126.42,CI 95%:37.87～185.36.结论 RA患者外周血OPG水平明显降低,RANKL水平明显升高,它们的变化与骨密度密切相关.外周血RANKL水平升高为RA患者中骨质疏松发生的独立危险因素.     

抗瓜氨酸蛋白抗体与类风湿关节炎继发骨质疏松的相关性

摘要：目的 分析ACPAs抗体（主要是AMCV和ACCP）与类风湿关节炎（rheumatoid arthritis，RA）患者继发骨质疏松以及与骨密度、骨代谢指标的相关性。方法 根据纳入标准及排除标准选取内蒙古科技大学包头医学院第一附属医院就诊的591例RA患者，详细记录患者的临床资料。采用ELISA法检测AMCV、ACCP、三种亚型RF以及骨代谢指标PINP、β-CTX、N-MID OC和25HVD；采用DXA检测RA患者髋关节及腰椎的BMD、BMC、Z值和T值；采用SPSS 20软件进行统计分析。结果 AMCV、ACCP阳性组较阴性组比较，IgA、IgM、三种亚型RF水平高，25HVD水平低。PINP、N-MID OC与病程呈正相关，骨密度指标与病程呈负相关；25HVD与ACCP、AMCV、三种亚型RF呈负相关。PINP和N-MID OC水平随病程增加而升高，25HVD和骨密度指标水平随病程增加而下降。骨质疏松组与骨量正常组和骨量减少组相比较，RA患者的年龄更大，病程更长，三种亚型RF水平更高。结论 ACPAs抗体与RA患者25HVD呈负相关；RA患者的骨密度及骨代谢与病程呈负相关；继发骨质疏松的RA患者病情更为复杂。     

定量CT在类风湿关节炎合并骨质疏松诊断中的应用价值

目的 分析定量CT（QCT）在类风湿关节炎（RA）合并骨质疏松（OP）诊断中的特异性和灵敏度，以及QCT评定RA患者骨量流失的影响因素，探讨QCT在RA患者合并OP诊断和病情评估中的价值。方法 选取112例确诊的类风湿关节炎患者为研究对象，QCT组（56例），双能X线组（56例），两组患者分别采用QCT及DXA检测骨密度。收集患者的一般资料，包括年龄、性别、体质指数、病程（月）、既往疾病和用药情况。同时收集患者的RA相关临床表现、辅助检查及骨密度检查结果。采用受试者工作特征曲线（ROC曲线）分析QCT诊断OP的特异性和灵敏度，多重线性回归分析QCT组患者骨量流失与RA临床表现、辅助检查的相关性。结果 ①经过对比，两组的一般资料差异无统计学意义（P>0.05)；②DXA诊断类风湿关节炎患者合并骨质疏松的检出率为44.6 %，QCT测定类风湿关节炎患者合并骨质疏松的检出率为51.9 %。ROC曲线分析显示QCT对RA合并OP诊断的灵敏度为0.739，特异度为0.618；③QCT组研究对象的骨量流失与RA患者的临床表现、疾病活动指标无明显相关性（P>0.05），但与RA特异性抗体抗核周因子抗体（APF）相关。结论 QCT对RA合并OP的检出率高于DXA，有着较好的灵敏度和特异性，可作为RA合并OP诊断的重要手段。     

风湿活动度预测绝经后女性类风湿关节炎患者骨密度的研究

目的探讨能够预测绝经后女性类风湿关节炎(Rheumatoid Arthritis RA)患者骨质疏松的指标。方法收集100例绝经后女性RA患者一般临床资料包括年龄、病程、血沉、C反应蛋白、类风湿因子、抗环瓜氨酸肽抗体、关节疼痛数目、关节肿胀数目,采用双能量X线骨密度仪测量腰椎、股骨及全身总的平均骨密度,比较临床资料并分析可能影响骨密度的因素。结果1.绝经后女性类风湿关节炎患者骨质疏松比例为33%,骨量减少比例47%,骨量正常比例20%。2.骨质疏松组的年龄、病程、血沉、关节疼痛数目、DAS28均高于非骨质疏松组,且有统计学意义。3.采用Logistic回归分析结果显示,年龄和DAS28是绝经后女性RA患者骨密度的独立危险因素。4.骨密度T值为诊断骨质疏松的金标准绘制受试者工作曲线,计算DAS28、年龄诊断骨质疏松的切点为5.3分和59.5岁。结论风湿活动度和年龄对于绝经后女性RA患者有较强的骨质疏松预警作用。     

血清骨代谢标记物对预测类风湿关节炎关节破坏的意义

目的：探讨血清骨代谢标记物与RA患者关节破坏的相关性。方法选取140例住院RA患者,90例同期健康人作为研究对象。采用DEXA测定RA者腰椎（ L1～L4）及股骨上端骨密度值,根据T值分为正常骨量、低骨量、骨质疏松组3组;另根据双手X线结果显示关节破坏程度分为Ⅰ、Ⅱ、Ⅲ、Ⅳ期组;同时检测患者血清CTX、25（ OH） D、TRACP－5b、PTH、血钙、血磷、抗CCP抗体、RF、CRP、ESR。结果 RA组TRACP－5b、CTX水平明显高于健康对照组（Z＝－2．747,－4．809,P＜0．01）,25（OH）D水平明显低于健康对照组（Z＝－6．152,P＜0．001）;TRACP－5b与病程、关节压痛个数、CTX呈正相关（r＝0．193, r＝0．189, r＝0．196,P＜0．05）,随着疾病活动度的加重,TRACP－5b水平呈现递增趋势,且骨质疏松组TRACP－5b水平高于正常骨量组,但未达统计学差异;CTX与关节肿胀个数、25（OH）D呈正相关（r＝0．215, r＝0．192,P＜0．05）,其水平在疾病重度活动组明显高于中低度组;X线Ⅰ期组患者与其他各组相比年龄较小,病程较短,关节破坏程度轻;Ⅰ期、Ⅱ期组骨质疏松患病率明显低于Ⅲ期、Ⅳ期组（ P＜0．05）;骨量丢失随年龄增长、病程的延长、疾病活动度的加重而增加。结论骨代谢标记物与RA患者关节破坏有一定的相关性,联合检测多种骨代谢标记物可望预测关节破坏的程度。     

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.     

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.     

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.     

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.     

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.