慢性肾脏病患者血浆成纤维细胞生长因子23水平与骨矿物质代谢的相关性分析

目的观察分析血浆成纤维细胞生长因子23(FGF-23)水平与慢性肾脏病(CKD)患者骨矿物质代谢的相关性。方法选择2015年1月至2017年6月经实验室、影像学等检查确诊为CKD的患者105例作为CKD组,按照肾小球滤过率估计值(eGFR)分为1~5期;选择同期就诊于体检中心且性别、年龄相当的健康体检者30例作为健康组。比较分析两组血红蛋白(Hb)、血浆白蛋白(ALB)、血浆FGF-23、肾小球滤过率(GFR)情况及不同CKD分期患者间血钙、血磷、碱性磷酸酶(ALP)、甲状旁腺激素(PTH)水平,利用Spearman相关分析探讨CKD患者血浆FGF-23水平与血钙、血磷、ALP等指标之间的关系。结果 CKD组的FGF-23显著高于健康组(P<0.05),而Hb、GFR显著低于健康组(P<0.05),并且存在钙磷代谢紊乱、低白蛋白血症。不同CKD分期患者间血磷及血清ALP水平随肾功能的下降有增高趋势,但差异无统计学意义(P>0.05);血钙随GFR下降有下降趋势,但差异无明显统计学意义(P>0.05);PTH水平随CKD分期增高而增高,FGF-23水平随肾功能的降低而增加(P<0.05)。以FGF-23为因变量,以血钙、血磷、ALP、PTH为自变量进行Spearman相关分析。结果显示,FGF-23与血钙(r=-0.77,P<0.05)呈负相关,FGF-23与血磷(r=0.21,P<0.05)、ALP(r=0.85,P<0.01)、PTH(r=0.675,P<0.05)呈正相关。结论 CKD患者外周血FGF-23水平与骨矿物质代谢有一定的相关性。血清FGF-23与血清中钙、磷、PTH具有一定的关系。正常人的血液循环中有FGF-23表达不高,但在高磷饮食、使用活性维生素D过程中,患者血清FGF-23水平也明显升高。FGF-23的调控可能是维生素D、钙、磷、iPTH等多种因素共同作用的结果。通过早期检测血清中FGF-23与钙、磷、ALP的水平,可为患者赢取更多的治疗时间,为患者获益。     

慢性肾脏病3～4期患者骨矿物质代谢紊乱的调查

目的 调查慢性肾脏病（chronickidney disease,CKD）3 ～4期患者慢性肾脏病矿物质及骨代谢紊乱（chronic kidney disease-mineral and bone disorder,CKD-MBD）的状况和检测有关骨代谢的指标.方法 检测111例CKD3～4期患者的血钙、血磷、血清全段甲状旁腺素（intact parathyroid hormone,iPTH）,并随机对其中20例患者行25羟维生素D[25（OH）D]及骨性碱性磷酸酶（bone-alkaline phosphare,b-ALP）的检测.结果 CKD3 ～4期患者矫正钙分别为（2.25 ±0.12 mmol/L）和（2.20±0.14 mmol/L）,血磷分别为（1.20 ±0.23 mmol/L）和（1.36 ±0.28 mmol/L）,iPTH分别为（73.18±51.77pg/mL）和（118.95±64.97pg/mL）,低钙血症的发生率分别为2.22％和6.06％,高磷血症的发生率分别为0％和7.58％,SHPT的发生率分别为37.78％和48.48％.CKD4期患者与CKD3期的患者相比,血钙显著性下降（P＜0.05）,iPTH水平显著升高（P＜0.05）,iPTH水平与血磷（r=0.103,P＞0.05）成正相关,与GFR（r=-0.422,P＜0.01）、血钙（r=-0.268,P＜0.01）成负相关.多元逐步回归分析显示,血钙、血磷、GFR是iPTH的独立影响因素（复相关系数R=0.482,p＜0.05）.CKD3～4期患者b-ALP（74.476±56.056ng/mL）,显著高于健康人（24.141±14.741ng/mL）（P＜0.01）,而25（OH）D（173.763±52.375ng/mL）显著低于健康人（306.995±93.085ng/mL）（P＜0.05）.结论 CKD早期患者存在CKD-MBD及骨代谢异常,且随着疾病的进展而愈加明显,应重视并早期干预,从而改善预后.     

成纤维细胞生长因子-23与慢性肾病患者钙磷代谢的相关性研究

目的：检测CKD3～5期患者血中成纤维细胞生长因子23（FGF-23）水平,探讨FGF-23与钙磷代谢的关系。方法：采用酶联免疫分析法（ELISA）对108例CKD3～5慢性肾脏疾病患者及20例健康志愿者进行血清全段FGF-23测定,同时测定血清25（OH）D3、iPTH、血清肌酐（Scr）、血钙（Ca2＋）、磷（P3-）、碱性磷酸酶（ALP）、血红蛋白（Hb）、白蛋白（Alb）、C反应蛋白等指标。观察各期患者以上指标的变化,及其与FGF-23的关系。结果：（1）CKD各组患者血清FGF-23水平均显著高于对照组。CKD各期FGF-23水平逐步升高,组间差异有统计学意义。（2）Pearson相关分析结果显示：非透析组血清FGF-23水平与肌酐清除率、血红蛋白、校正血钙、血磷存在显著负相关关系（P〈0.01）;与钙磷乘积、全段甲状旁腺激素（P〈0.01）和白蛋白（P〈0.05）存在直线正相关关系。透析组血清FGF-23水平与全段甲状旁腺激素及C-反应蛋白（P〈0.01）存在正相关关系。（3）非透析组多元回归结果显示：血磷、iPTH、肌酐清除率是血清FGF-23水平的独立相关因素,其回归方程为：Y（FGF-23）=1.700＋0.106（P）＋0.048（LogPTH）-0.003（Ccr）。透析组PTH、CRP是影响FGF-23的主要变量。结论：CKD患者血FGF-23明显升高,血磷和甲状旁腺激素可能是CKD患者血FGF-23水平的调节因子。     

腹膜透析患者成纤维细胞生长因子23与骨代谢的关系

目的 探讨腹膜透析患者成纤维细胞生长因子23（FGF-23）与钙磷代谢及骨密度的关系。 方法 研究对象为中南大学湘雅医院持续性不卧床腹膜透析（CAPD）患者59例,按照世界卫生组织骨密度评分标准将CAPD患者分为骨质正常、骨质降低、骨质疏松3组,另设健康对照组30例。酶联免疫吸附法检测FGF-23、1,25（OH）2VitD3;免疫化学发光法检测甲状旁腺激素（PTH）;自动生化分析仪测量血钙（Ca）、磷（P）;双能X射线吸收仪测量骨密度（BMD）。 结果 CAPD患者股骨颈部位的骨质疏松率为23.7%,腰椎部位的骨质疏松率为35.6%。3组间FGF-23水平差异无统计学意义,但CAPD组FGF-23水平显著高于健康对照组（P ＜ 0.01）。Pearson相关分析显示log[FGF-23]与血磷呈正相关（r = 0.604,P ＜ 0.01）;与肾小球滤过率（GFR）、1,25（OH）2VitD3呈负相关（r = -0.651,P ＜ 0.01;r = -0.401,P ＜ 0.05）;与 PTH、Ca、T值、透析龄无相关。 结论 CAPD患者血FGF-23显著增高,血磷、肾功能状态、1,25（OH）2VitD3均可调节血FGF-23水平,但FGF-23与骨密度降低无直接关系。     

上海市绝经后妇女冬季维生素D状况

目的调查上海市绝经后妇女在冬季(12月份)维生素D的状况。方法在社区101例年龄63.7±7.0岁健康绝经后妇女中,检测血清25羟维生素D[25(OH)D]、甲状旁腺激素(PTH),同时检测血钙、磷、碱性磷酸酶、肝肾功能及空腹血糖。所有研究对象均用双能X线吸收仪检测腰椎和股骨近端骨密度(BMD),同时用问卷调查生活方式。结果本研究101例绝经后女性血清25(OH)D平均值为17.09 ng/ml,PTH平均值51.0 pg/ml,维生素D缺乏者占(<20 ng/ml)68%,维生素D不足者(20～29 ng/ml)占了30%,只有2例维生素D充足(>30 ng/ml)占2%。PTH均值在维生素D缺乏组中(53.7 pg/ml)高于维生素D不足组(44.8 pg/ml),有统计学差异(P<0.05);但未发现血清25(OH)D与PTH有线性回归关系。同时未发现血清25(OH)D与血钙、BMD或BMI相关。结论上海市健康绝经后妇女在冬季维生素D普遍不足,维生素D缺乏组的PTH显著高于维生素D不足组,不良的生活方式及低维生素D和钙的摄入应引起重视。     

慢性肾脏病患者成纤维细胞生长因子23与肾功能及钙磷代谢的关系

目的 探讨慢性肾脏病（CKD）患者随着肾功能的变化,其成纤维细胞生长因子23（FGF23）与钙磷代谢的关系。 方法 研究对象为2008年8月至2009年4月在上海交通大学附属第一人民医院肾内科住院的初诊CKD患者72例,按照肾小球滤过率（GFR）水平分为5组,另设健康对照组20例。抽取受试者静脉血并分离血清,以酶联免疫法检测FGF23、25（OH）VitD3、1,25（OH）2VitD3;全自动生化分析仪测量钙（Ca）、磷（P）、血肌酐（Scr）、尿素氮（BUN）、白蛋白（Alb）水平;免疫放射法测定全段甲状旁腺激素（iPTH）。 结果 CKD患者血清FGF23水平随GFR降低逐渐升高,在CKD4期和5期时,血FGF23、P、iPTH上升明显,1,25（OH）2VitD3显著下降,与CKD1期差异有统计学意义（均P < 0.05）。CKD2~3期与CKD1期的FGF23、P、Ca、iPTH、活性维生素D水平差异均无统计学意义。血Ca、25（OH）VitD3随着肾功能下降有降低趋势,但各期间差异均无统计学意义。Pearson相关分析显示,CKD1~5期logFGF23与P、logiPTH呈正相关（r = 0.653,P < 0.01;r = 0.800,P < 0.01）,与GFR、1,25（OH）2VitD3呈负相关（r = -0.753,P < 0.01;r = -0.265,P < 0.05),与Ca、25（OH）VitD3无相关。CKD1~3期logFGF23与logiPTH呈正相关(r = 0.374,P < 0.05),而与Ca、P、25（OH）VitD3、1,25（OH）2VitD3、GFR均无相关。CKD4~5期log FGF23与P、logiPTH呈正相关（r = 0.381,P < 0.05;r = 0.515,P < 0.01）,与GFR呈负相关（r = -0.654,P < 0.01）,与Ca、25（OH）VitD3、1,25（OH）2VitD3无相关。 结论 随着肾功能减退,血清FGF23、P、iPTH水平逐渐升高,活性维生素D水平逐渐下降,尤以CKD4~5期明显。在肾脏病早期阶段（CKD1~3期）血iPTH水平与FGF23有关。当GFR<30 ml/min时,肾功能状态、血磷、血iPTH均可影响血FGF23水平。     

贵阳城区男性血清25( OH) D水平与血清PTH及骨密度的相关性研究

目的了解贵阳城区男性血清25(OH)D水平与血清PTH、骨密度之间关系的阈值。方法用整群抽样的方法横断面调查贵阳城区20~79岁(46.2±14.9岁)健康男性居民634名。研究对象均问卷调查健康状况,测定血钙、血磷、血肌酐、血清25(OH)D水平和血清PTH浓度(美国DiaSorin放射免疫试剂盒),测定非优势(左)股骨近端股骨颈(neck)、全髋部(hip)及腰椎前后位(L1-L4)的骨密度(BMD)值(美国GE公司Lunar Prodigy双能x线骨密度仪)。结果1.资料较齐全的571名受试者中,维生素D营养状况正常[25(OH)D≥30.0 ng/ml]仅为103名(18.0%),维生素D营养状况异常者[25(OH)D30.0ng/ml]高达82%;2.血清25(OH)D水平与血清PTH浓度呈负相关,当25(OH)D水平低于20 ng/ml时,PTH开始升高;3.青中年男性骨密度值随血清25(OH)D水平在20 ng/ml以上明显升高,老年男性血清25(OH)D水平在10 ng/ml各部位骨密度增高,但达到20 ng/ml后,骨密度增长缓慢。结论贵阳市城区男性低血清25(OH)D水平较常见,血清25(OH)D水平低于20 ng/ml可能会导致甲状旁腺激素水平升高,维生素D营养状况对不同年龄段男性骨密度部位影响可能不同。     

超声评估慢性肾脏病患者肾功能的探索

目的:分析慢性肾脏病(CKD)患者超声参数与估算肾小球滤过率(e GFR)的关系，探索评估肾功能的最佳超声参数。方法:选取我院收治的CKD1～5期肾功能稳定且未进入透析的97例患者，由同一名B超专科医师测量患者双侧肾脏长径、皮质厚度、实质厚度、皮质回声，计算CKD超声积分，并收集患者的一般资料、血生化指标、血红蛋白等。分析各超声参数与e GFR的相关性，并进行多因素分析。绘制接受者操作特征(ROC)曲线，并估计曲线下面积，评估超声参数识别CKD3期(e GFR <60 ml/min)患者的能力。结果:(1)本研究97例患者平均e GFR (50.9±35.7) ml/min，平均肾长(9.62±1.24)cm，平均肾实质厚度(1.51±0.29) cm，平均肾皮质厚度(0.69±0.16) cm，肾皮质回声中位值2，平均CKD超声积分(5.16±3.67)。(2) e GFR与肾脏长径(r=0.756,P <0.01)、实质厚度(r=0.739,P <0.01)、皮质厚度(r=0.715,P <0.01)呈正相关，与皮质回声(r=-0.786,P <0.0...     

血液灌流联合血液透析疗法对肾衰竭伴钙磷代谢异常患者血清PTH水平变化及临床效果研究

目的:探讨血液灌流联合血液透析治疗肾衰竭伴钙磷代谢异常患者的临床效果及对患者血清甲状旁腺素(parathyroid hormone,PTH)水平的影响。方法:选取2016年9月—2019年10月在芜湖市第二人民医院肾内科行维持性血液透析治疗的肾衰竭伴钙磷代谢异常患者110例进行病例对照研究,根据治疗方式不同分为对照组和观察组,每组各55例,对照组给予单纯血液透析治疗(hemodialysis,HD),观察组给予血液灌流(hemoperfusion,PH)联合血液透析治疗,检测并记录两组患者治疗前后β_2-微球蛋白(β_2-MG)、血肌肝(Scr)、尿酸(UA)等肾功能相关指标,成纤维细胞生长因子23(FGF-23)、Klotho蛋白、血钙、血磷及血清PTH水平变化。结果:两组患者治疗后肾功能指标均有所改善,观察组β_2-MG(12.02±2.76)mg/L,明显低于对照组β_2-MG(20.12±3.04)mg/L,其余指标UA、ScrL与对照组比较差异无统计学意义;治疗后观察组FGF-23(58.06±7.23)ng/L低于对照组,Klotho蛋白表达(149.71±18.53)U/L明显高于对照组(P0.05),差异有统计学意义;治疗后观察组血钙(2.23±0.35)mmol/L,达标率81.82%,血磷(2.38±0.41)mmol/L,达标率63.64%,钙磷乘积达标率87.27%,与对照组血钙、血磷、钙磷乘积达标率比较明显升高(P0.05),差异有统计学意义;治疗后观察组PTH(256.72±45.75)pg/ml,明显低于照组PTH(420.68±69.24)pg/ml,观察组治疗后28例PTH水平达标,达标率50.91%,对照组治疗后达标率仅有18.18%,明显低于观察组(P0.05),差异有统计学意义。结论:血液灌流联合血液透析治疗肾衰竭伴钙磷代谢异常患者临床效果优于单纯血液透析治疗,能够有效的改善肾患者钙磷代谢异常,降低患者血清PTH水平,减少并发症的发生。     

血清骨代谢指标对慢性肾脏病患者骨质量的评价作用

[摘要]目的：探讨血清骨代谢指标对慢性肾脏病（CKD）患者骨质量好坏的评价意义。方法：收集2012年1月～2013年11月上海市第六人民医院肾内科首次住院的CKD患者95例,将患者按GFR分为CKD3期组、CKD4期组及CKD5期组。测定各组患者血清钙（ca2＋）、磷（P3-）、骨代谢指标碱性磷酸酶（ALP）、骨钙素N端中分子（N—MID）、13胶原特殊序列（B—CTX）、25-羟维生素D[25-（OH）VD]和甲状旁腺激素（PTH）水平。结果：CKD三组患者随着GFR的逐渐下降,血ca2＋、25（OH）D呈下降趋势,血P”、PTH、N—MID、B—CTX则呈逐渐上升趋势,组间差异有统计学意义（P〈0．05）;血ALP组间差异总体无统计学意义（P〉0．05）;Pearson直线相关分析显示GFR分别与血P3-（r=-0．494）、N—MID（r=-0．577）、B—CTX（r=-0．518）呈负相关（P＜0．001）,与25（OH）D（r=0.289,P=0.008）呈正相关;血P3-与N—MID（r=0.5）、B—CTX（r=0．497）、PTH（r=0．528）分别呈正相关（P＜0.001）,与25（OH）D呈负相关（r=-0．276,P=0．012）;PTH、N—MID、B—CTX三者互为正相关,PTH与N—MID（r=0．532）、PTH与B—CTX（r=0．551）、N—MID与β-CTX（r=0．641）分别呈正相关（P＜0．001）。结论：CKD患者血清Ca2＋、P3-、PTH、AKP、N—MID、B—CTX、25（OH）D相互作用影响骨质量。血清骨代谢生化指标在评估CKD患者骨质量方面具有重要有益作用。     

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.