维生素k2对维甲酸致大鼠骨质疏松症的抑制作用

目的 比较VitK2(20)、K2(35)和柠檬酸-苹果酸钙(CCM)对维甲酸致大鼠骨质疏松症的抑制作用.方法 取60只3月龄雌性大鼠随机均分为正常对照组、模型组、1 mg/kg Vit K2(20)组、0.01 mg/kg Vit K2(35)组、100 mg/kg CCM组和0.125 mg/kg的尼尔雌醇(nilestriol)片阳性对照组.正常对照组以二次蒸馏水10 ml*kg-1*d-1灌胃,其余组按维甲酸70 mg*kg-1*d-1灌胃共15 d,从第9天起上午灌服维甲酸,下午分别灌服VitK2(20)、K2(35)、CCM和尼尔雌醇,灌胃量均为10 ml*kg-1*d-1,连续14 d.结果 与模型组比较,1 mg/kg VitK2(20), 0.01 mg/kg K2(35)和100 mg/kg CCM灌胃给药14 d可明显提高大鼠血清钙含量,显著升高股骨骨密度,并且骨密度与股骨灰重呈线性相关,其中VitK2(35)组的子宫指数、卵巢指数均明显高于其他药物组(P<0.05);VitK2组骨小梁厚度增加,表面积百分率明显增大,VitK2(35)组的骺板软骨细胞增生明显且有许多新的骨小梁形成.结论 VitK2(20)、K2(35)和CCM对维甲酸致大鼠的骨质疏松症有明显抑制作用,在同等剂量下,VitK2活性约为CCM的102～104倍,VitK2(35)尤为显著.     

云克治疗糖皮质激素性骨质疏松模型大鼠的实验研究

目的 探讨云克对地塞米松诱导的骨质疏松症大鼠的治疗作用.方法 12周龄的雌性Wistar大鼠30只,随机分为3组,对照组、模型组和治疗组,每组10只.模型组和治疗组给予5mg/kg地塞米松肌注,1次/周,连续注射12周,对照组肌注等剂量的生理盐水.DEXA骨密度仪检测大鼠股骨骨密度,各组均取2只处死,HE染色观察股骨结构的病理改变鉴定骨质疏松大鼠模型是否构建成功.骨质疏松模型构建成功后,治疗组大鼠尾静脉注射云克(0.05 μg/kg),对照组和模型组注射等剂量的生理盐水,1次/周,连续注射15周,治疗前后尾静脉采血,ELISA法检测血清骨碱性磷酸酶和酒石酸酸性磷酸酶水平的变化.检测各组大鼠治疗后的股骨骨密度,之后,处死各组大鼠,取股骨,免疫组化法检测大鼠股骨骨保护素的变化,HE染色观察骨结构的病理改变.结果 (1)模型组和治疗组大鼠经地塞米松处理12周后,股骨骨密度较对照组明显降低(P＜0.05);病理改变为骨小梁稀疏、数目明显减少甚至断裂,而对照组骨小梁结构较完整.(2)与模型组相比,治疗组大鼠血清骨特异碱性磷酸酶水平明显升高(P＜0.05),而抗酒石酸酸性磷酸酶水平有所下降,但无统计学差异(P＞0.05).(3)治疗组治疗后血清骨特异碱性磷酸酶水平明显升高(P＜0.05),而抗酒石酸酸性磷酸酶水平有所下降,但无统计学差异(P＞0.05).(4)与模型组和治疗前相比,治疗组大鼠股骨骨密度无明显改变(P＞0.05).(5)与模型组相比,治疗组大鼠股骨骨保护素表达明显增加.(6)云克治疗后,治疗组大鼠股骨有新生骨小梁的广泛形成,骨小梁结构破坏较模型组明显减轻.结论 云克对糖皮质激素性骨质疏松大鼠有治疗作用.     

肉桂醛对去卵巢诱导的骨质疏松大鼠模型骨密度和骨量的保护作用

目的探讨肉桂醛对去卵巢手术诱导的骨质疏松症大鼠模型中骨密度(BMD)和骨量的影响。方法 24只雌性Sprague-Dawley大鼠经过去卵巢手术或假手术。12周后大鼠被分为肉桂醛组(RGQ组)、对照组(CON组)和去卵巢组(OVX组)。检测所有大鼠股骨和腰椎骨密度(BMD),血清细胞因子肿瘤坏死因子-α(TNF-α)和IL-6(Interleu-kin)水平和进行股骨组织形态学分析。结果去卵巢手术显著降低大鼠的BMD值、骨小梁数量、小梁厚度和小梁面积;此外,显著增加骨小梁分离度和血清TNF-α和IL-6水平;和CON组比较差异有统计学意义(P0.05)。而RGQ治疗后,RGQ组大鼠大鼠的BMD值、骨小梁数量、小梁厚度和小梁面积显著增加,骨小梁分离度和血清TNF-α和IL-6水平显著降低;和CON组比较差异有统计学意义(P0.05)。结论肉桂醛对去卵巢手术诱导的骨质疏松症大鼠模型中骨密度(BMD)和骨量有保护作用。     

淫羊藿总黄酮对摘除卵巢大鼠骨质疏松症的防治作用

用除卵巢法结合低钙饲料建立大鼠骨质疏松模型。淫羊藿总黄酮在75-300mg/kg剂量范围内连续给药3个月，与模型组大鼠比较，能明显提高大鼠股骨表现观面密度（W/LD）和骨密度（BMD）而不升高子宫系数及血清雌二醇（s-E2)水平，并有提高骨Ca、骨P的趋势。高剂量组大鼠血清碱性磷酸酶（s-ALP)降低，股骨骨密度升高。骨形态计量学结果表明，高剂量组大鼠骨小梁吸收表面百分率（TRS%）和形成表面百分率（TFS%）等参数明显降低，骨小梁体积百分率（TBV%）明显提高。     

硝酸甘油间断性给药对大鼠糖皮质激素性骨质疏松模型骨密度及血清N0S水平影响的初步研究

目的 观察大鼠糖皮质激素性骨质疏松模型血清一氧化氮合酶(NOS)变化及硝酸甘油(Nitroglycerin,NG)对糖皮质激素性骨质疏松的防治作用.方法 健康3月龄SD雄性大鼠30只,体重(251±12.5)g,随机分为3组,每组10只.模型组(A)给予生理盐水和地塞米松,实验组(B)给予地塞米松和硝酸甘油,对照组(C)给予生理盐水.试验8周后测量各组大鼠第3腰椎及右股骨中段骨密度,并行切片HE染色观察骨组织显微结构,测量大鼠体重、血清一氧化氮合酶(NOS)、碱性磷酸酶含量.结果 8周后3组体重差异明显(P＜0.01),模型组体重低于实验组,实验组低于对照组.实验组第3腰椎骨密度值明显高于模型组(P＜0.01).对照组骨密度值与实验组比较差异无显著性意义(P＞0.05).各组股骨骨密度值无明显差异(P＞0.05).实验组第3腰椎骨小梁形态结构与对照组相似,模型组骨小梁稀疏,断裂.模型组ALP较对照组及实验组明显升高(P＜0.01),NOS各组差异不明显(P＞0.05).结论 血清NOS水平不宜作为激素性骨质疏松症的评价指标,硝酸甘油可有效预防糖皮质激素性骨质疏松的发生.     

地塞米松促进大鼠血管钙化的实验研究

目的 在大鼠血管钙化模型上,探讨地塞米松对血管钙化的影响.方法 在维生素D3加尼古丁诱导制备的大鼠血管钙化模型上,给予地塞米松肌肉注射,制备血管钙化加骨质疏松复合模型,观察地塞米松对血管钙化的影响.Wistar大鼠共分为4组,即对照组、骨质疏松组、钙化组和钙化加骨质疏松组.8周后,进行主动脉钙含量测定、碱性磷酸酶(alkaline phosphatase,ALP)活性及骨钙素(osteocalcin,OC)含量测定,判断血管钙化程度;用骨密度仪测定大鼠骨密度以反映骨质疏松程度.结果 在钙化加骨质疏松组,其血管钙含量(183.39±7.22)nmol/(mg·pr)高于单独钙化组(111.72 ±8.58)nmol/(mg·pr)(P＜0.01);钙化组腰椎骨密度(0.18 ±0.01)g/cm2低于正常对照组(0.20±0.006)g/,cm2(P＜0.01);结论 地塞米松所致的骨质疏松症可能会加重血管钙化;血管钙化也可能促进骨质疏松症的发生,其机制有待进一步探讨.     

五味子甲素对去卵巢骨质疏松大鼠SDF-1/CXCR4信号通路的影响

目的 探究五味子甲素对去卵巢骨质疏松症大鼠的治疗作用以及对基质细胞衍生因子-1（SDF-1）/CXC趋化因子受体4（CXCR4）信号通路的影响。方法 采用去卵巢法构建骨质疏松症大鼠模型，将建模成功的60只大鼠随机分为模型组、五味子甲素低（20 mg/kg）、高（40 mg/kg）剂量组、阿仑膦酸钠（1 mg/kg）组、五味子甲素高剂量+SDF-1/CXCR4通路抑制剂（AMD3100）（40 mg/kg+5 mg/kg）组，每组12只。另取12只大鼠作为假手术组（手术过程中仅暴露卵巢不切除）。建模结束后，各组给予对应药物干预，每天1次，连续12周。采用双能 X 射线骨密度仪检测大鼠左、右股骨骨密度（BMD）；酶联免疫吸附法检测大鼠血清中Ⅰ型胶原交联羧基末端肽（CTX-Ⅰ）、骨钙素（OC）水平；HE染色观察大鼠股骨组织病理学变化；荧光定量PCR法检测大鼠股骨组织中SDF-1、CXCR4信使RNA（mRNA）水平；蛋白印迹法检测大鼠股骨组织中SDF-1、CXCR4蛋白水平。结果 假手术组大鼠股骨组织骨小梁结构正常，排列规则；与假手术组相比，模型组大鼠股骨组织骨小梁稀疏断裂，数量减少，排列紊乱，左、右股骨BMD、血清中OC、CTX-Ⅰ水平、股骨组织中SDF-1、CXCR4 mRNA和蛋白水平显著降低（P<0.05）；与模型组相比，五味子甲素低、高剂量组大鼠股骨组织病变程度依次减轻，左、右股骨BMD、血清中OC、CTX-Ⅰ水平、股骨组织中SDF-1、CXCR4 mRNA和蛋白水平依次升高（P<0.05）；阿仑膦酸钠组和五味子甲素高剂量组大鼠股骨组织病理学变化及各项指标差异比较均无统计学意义（P>0.05）；AMD3100可逆转高剂量五味子甲素对骨质疏松症大鼠上述指标的改善效果（P<0.05）。结论 五味子甲素可抑制骨质疏松症大鼠BMD的下降，减轻大鼠股骨组织病变，改善大鼠骨质疏松，其机制可能与激活SDF-1/CXCR4信号通路有关。     

枸杞子乙酸乙酯提取物急性毒性及对切除卵巢大鼠骨质疏松的防治作用

目的研究枸杞子乙酸乙酯提取物的急性毒性及抗骨质疏松作用。方法枸杞子乙酸乙酯提取物以1.25 g/kg、2.50g/kg、5.00 g/kg、10.00 g/kg对C57/BL6小鼠灌胃给药,连续观察7天,记录急性毒性反应。7天后,观察内脏主要器官的病理变化。将雌性SD大鼠切除卵巢构建绝经后骨质疏松症模型,用125 mg/kg枸杞子乙酸乙酯提取物溶液连续给药3个月,Micro-CT扫描分析检测,评价对去卵巢大鼠骨质疏松症的作用。结果各给药组与对照组小鼠均未见明显的毒性反应症状,枸杞子乙酸乙酯提取物LD50及MTD10 g/kg。与切除卵巢模型组大鼠相比,枸杞子乙酸乙酯提取物组大鼠的股骨骨密度(P0.05)、骨体积比(P0.05)、骨小梁厚度(P0.05)和骨小梁数目(P0.05)有所增加,骨小梁间隔(P0.05)和骨表面积比(P0.05)有所减小,微观结构各项指标都优于模型组。结论枸杞子乙酸乙酯提取物毒性极小,能够起到一定的抗骨质疏松作用。     

中药葛根素对青年大鼠峰值骨量的影响研究

目的探究葛根素(puerarin,PR)是否能提高青年大鼠的峰值骨量,起到预防骨质疏松症的作用。方法 1月龄Wistar雌性健康大鼠36只,按随机数表法分为3组,每组12只,分别为对照组(control,CON)、淫羊藿苷组(icariin,ICA,阳性对照)和葛根素组(puerarin,PR)。ICA组灌胃淫羊藿苷25 mg/(kg·d),PR组灌胃葛根素15.4 mg/(kg·d),CON组灌胃等体积蒸馏水。待各组间骨密度有显著差异后(两个月后)处死所有大鼠,进行重要脏器的器官指数计算,采用HE染色进行病理学分析、双能X线骨密度仪检测椎骨和股骨离体骨密度、万能材料试验机进行骨生物力学检测、ELISA试剂盒进行血清骨代谢指标检测以及VG染色进行骨形态计量学的检测。结果在实验期间各组大鼠体重均呈上升趋势,但组间无显著差异;各组间主要脏器肺、肾、子宫等的器官指数无明显差异,病理学观察也未见异常改变;骨密度结果显示:灌胃给药前,CON组、ICA组和PR组大鼠全身骨密度均无统计学意义,灌胃4 w时,与CON组比较,ICA组和PR组大鼠全身骨密度有升高趋势,但无统计学意义(P均0.05),灌胃8 w时ICA组和PR组大鼠骨密度显著升高,且差异具有统计学意义(P均0.05);与CON组相比,ICA组和PR组股骨离体骨密度均显著升高(P均0.01),椎骨离体骨密度显著升高(P均0.05);生物力学结果:与CON组相比,ICA组和PR组大鼠股骨和椎骨的最大载荷值均显著升高(P0.01,P0.05),弹性模量值也均显著升高(P均0.05);骨形态计量学VG染色结果分析:与CON组相比,ICA组和PR组股骨中骨小梁数目(trabecular number,Tb.N)、骨小梁厚度(trabecular thickness,Tb.Th)和骨体积/组织体积(bone volume/tissue volume,BV/TV)值均显著升高(P均0.05),而骨小梁分离度(trabecular Spacing,Tb.Sp)显著下降(P0.01)。血清骨代谢指标检测结果:与CON组比较,ICA组和PR组骨钙素(osteocalcin,OC)含量值显著升高(P均0.05),而抗酒石酸酸性磷酸酶(tartrate-resistant acid phosphatase 5b,TRACP 5b)含量均显著降低(P均0.05)。结论葛根素能显著提高青年大鼠的峰值骨密度和骨质量,增强股骨和椎骨生物力学性能,改变骨形态计量学,其可能机制是具有提高骨形成和抑制骨吸收的双重活性。     

葛根素和白藜芦醇对青年大鼠峰值骨量的影响研究

目的:比较葛根素、白藜芦醇单体与二者的复合药物对大鼠峰值骨量的影响。方法 :选取雌性SPF级Wistar大鼠40只,体重109.45～119.44 g,平均115.87 g,大鼠适应3 d后采用随机数字表法将其分为4组,每组10只,分别为空白对照组(CON组,每日灌胃等体积的蒸馏水),葛根素组(PR组,每日灌胃15.4 mg/kg葛根素),白藜芦醇组(RES组,每日灌胃8.4 mg/kg白藜芦醇),复合药物组(P+R组,每日灌胃8.4 mg/kg白藜芦醇+15.4 mg/kg葛根素复合药)。每7 d监测1次大鼠体重,每月检测1次大鼠全身骨密度。3个月后处死全部大鼠。采用双能X线骨密度仪检测股骨和椎骨离体骨密度;采用万能材料试验机分析骨生物力学;采用VG染色分析骨形态计量学;采用ELISA试剂盒检测血清骨代谢指标及用Micro-CT扫描仪扫描股骨微结构。结果:各组大鼠在实验期间的体重变化无统计学意义;骨密度结果显示:与CON组比较,其余3组股骨和椎骨骨密度均显著升高,且R+P组显著高于PR组和RES组。股骨三点弯曲和椎骨压缩试验结果显示:与CON组相比,其余3组股骨和椎骨最大载荷值均显著升高,且P+R组高于PR组和RES组,而各组间弹性模量值无统计学意义;股骨VG染色结果显示:与CON组相比,其余3组骨小梁数目显著增加,分离度明显减低,且R+P组明显优于PR组和RES组,而各组间骨小梁厚度无显著变化。Micro-CT扫描重建图结果显示:与CON相比,其余3组股骨骨小梁结构紧密,数目较多,分离度小,连续性好,且R+P组显著优于RES和PR组;Micro-CT扫描指标结果显示:与CON组相比,其余3组股骨骨小梁数目(trabecular number,Tb.N)、骨小梁厚度(trabecular thickness,Tb.Th)显著增加,骨小梁分离度(trabecular spacing,Tb.Sp)显著降低,且差异具有统计学意义(P0.05),且R+P组显著优于RES和PR组。血清生化指标结果显示:与CON组相比,其余3组血清中骨钙素(osteocalcin,OC)水平均升高,抗酒石酸酸性磷酸酶5b(TRACP 5b)含量均下降,差异具有显著性,且P+R组显著高于PR组、RES组,而TRACP 5b含量无显著变化。结论:葛根素与白藜芦醇单体按1∶1比例组合而成的复合药在提高青年大鼠峰值骨密度和骨质量,增强骨生物力学性能,促进成骨细胞的矿化成熟,抑制破骨细胞骨吸收方面的药效显著优于葛根素和白藜芦醇单体的作用,表明中药复方或复合药将作为预防和治疗骨质疏松的新途径。     

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.