乌司他丁对大鼠肾缺血/再灌注损伤的保护作用

目的探讨乌司他丁对大鼠肾缺血/再灌注(I/R)损伤的作用及其机制.方法雄性SD大鼠75只,随机分为三组假手术对照组(C组)、肾I/R组(I组)、乌司他丁组(U组),每组25只.I组和U组大鼠夹闭双侧肾蒂45min后重新开放肾脏血供,制作肾脏I/R模型,C组不夹闭双侧肾蒂.U组缺血前30min及再灌注开始时静脉注射乌司他丁1.25万单位,I组分别静脉注射生理盐水1ml.各组在再灌注后0、2、6、12、24h时取标本,测定血尿素氮(BUN)和血肌酐(Cr)浓度,并制备肾脏病理切片,采用免疫组化方法测定热休克蛋白70(HSP70)和bcl-2蛋白的表达.结果与I组比较,C组在再灌注后各时点血清BUN和Cr浓度均降低(P＜0.05),U组在再灌注后12、24h时血清BUN和Cr浓度也降低(P＜0.05).C组肾脏未发现明显的形态学改变;I组近曲小管上皮细胞空泡变性和坏死,肾小管腔扩张,内可见管型和坏死脱落细胞,可见管周血管明显扩张淤血;U组近曲小管上皮细胞肿胀、颗粒变性,罕见管型,管周稍有淤血.与I组比较,C组在再灌注后0、6、12、24h时Paller评分降低(P＜0.05),U组在再灌注后0、6、24h时Paller评分也降低(P＜0.05),C组再灌注后12、24h时HSP70表达降低(P＜0.05),U组在再灌注后6、24h时bcl-2蛋白表达增强(P＜0.05).结论乌司他丁对肾脏I/R损伤有保护作用,其机理可能与上调肾脏bcl-2蛋白表达有关.     

肾缺血/再灌注时肾组织损伤及细胞凋亡的实验研究

目的：检测肾缺血／再灌注不同时问点肾组织、功能损伤及细胞凋亡的变化，探讨细胞凋亡在肾缺血／再灌注损伤中发生的机制。方法：应用苦味酸法和二乙酰一肟反应法测定大鼠肾缺血／再灌注不同时间点血肌酐和尿素氮值检测肾功能变化，用HE染色光镜下观察缺血／再灌注石蜡包埋切片肾组织损伤形态学改变，用酚／氯仿抽提小片断DNA，在琼脂糖电泳上测定不同时间点DNA Ladder及利用原位凋亡检到法观察各时间点TUNEL阳性细胞数检测细胞凋亡情况。结果：肾功能检测发现，缺血45min后血肌酐和尿素氮值明显增高和正方对照差异显(P＜0.05)，再灌注早期上升缓慢，3h后再次增高，组内对比差异显(P＜0．05)。HE染色光镜下观察肾组织细胞以近端肾小管变性为主、坏死轻微，缺血／再灌注各时间点组织损伤变化与肾功能变化规律相一致。琼脂糖电泳和TUNEL检测在缺血45min再灌注3h时可测到DNA Ladder和TUNEL阳性细胞增加，再灌注12h细胞凋亡最明显。结论：肾缺血／再灌注可引起肾组织轻、中度的损伤和明显的肾功能损害；肾缺血／再灌注后期肾组织及功能损伤加重可能与细胞凋亡的发生有关。     

乌司他丁对高龄食管癌患者术后肺肝肾功能的影响

目的 研究乌司他丁对高龄食管癌患者术后肺、肝、肾功能的影响.方法 收集2005年1月至2008年1月第三军医大学西南医院收治的40例高龄食管癌患者的临床资料,按照随机数字表法分为对照组、乌司他丁组.两组患者均于术后给予7 d全胃肠外营养(TPN),其中乌司他丁组同时给予乌司他丁40万U/d静脉滴注.分别于术前及术后第2天、第6天晨抽取两组患者的动、静脉血测量PaO_2、PaCO_2、氧分压/吸入气体氧含量(PaO_2/FiO_2)、ALT、AST、TBil、尿酸、尿素氮、肌酐.采用t检验和χ~2检验分析结果.结果 术后第6天,乌司他丁组和对照组的PaO_2分别为(87.3±4.2)mm ng(1 mm Hg=0.133 kPa)和(79.0±4.3)mm Hg,PaO_2/FiO_2分别为(416±20)mm Hg和(376±20)mm Hg;两组比较差异有统计意义(t=6.2,6.2,P<0.05).乌司他丁组和对照组的ALT分别为(23±7)U/L和(39±8)U/L,AST分别为(38±8)U/L和(50±9)U/L,TBil分别为(13.4±3.0)μmol/L和(24.5±6.0)μmol/L,两组比较差异有统计学意义(t=7.0,4.4,7.6,P<0.05).乌司他丁组和对照组的尿酸分别为(279±84)μmol/L和(386±67)μmol/L,尿素氮分别为(4.1±1.7)mmol/L和(8.9±2.7)mmol/L,肌酐分别为(66±12)μmol/L和(95±38)μmol/L,两组比较差异有统计学意义(t=4.4,6.4,3.3,P<0.05).乌司他丁组并发症发生率低于对照组(χ~2=4.8,P<0.05).结论 在术后常规行TPN治疗的基础上,应用乌司他丁可以更好地保护和改善高龄食管癌患者的肺、肝、肾功能.     

吡咯烷二巯基氨甲酸对大鼠肾缺血再灌注的保护作用及机制

目的 探讨吡咯烷二巯基氨甲酸(PDTC)对大鼠肾缺血再灌注的保护作用及可能的机制.方法 选择成年、健康及雄性的Wistar大鼠56只,随机分为缺血再灌注损伤(IRI)组,PDTC组及对照组.IRI组:24只,建立大鼠肾缺血再灌注模型;PDTC组:24只,缺血再灌注前15 min经鼠尾静脉注射PDTC 150 mg/kg,其余步骤同IRI组;对照组:8只,不给予缺血再灌注处理.IRI组和PDTC组分别于再灌注后2、6和24 h检测大鼠血清肌酐(Cr)和尿素氮(BUN)水平;检测肾组织中自细胞介素8(IL-8)和肿瘤坏死因子α(TNF-α)的含量;逆转录聚合酶链反应(RT-PCR)检测肾组织中核因子-κB(NF-κB)和诱导型一氧化氮合酶(iNOS)mRNA表达水平;苏木素-伊红(HE)染色观察大鼠肾组织的病理变化.取对照组的各项数据作为正常对照.结果 IRI组大鼠再灌注后各时间点的血Cr、BUN、IL-8及TNF-α含量、NF-κB和iNOS mRNA表达水平均高于对照组和PDTC组(P<0.05).再灌注后6 h时,PDTC组大鼠肾组织中IL-8和TNF-α含量与对照组比较,差异无统计学意义(P>0.05).再灌注后24 h时,PDTC组大鼠各项生化指标与对照组相比,差异均无统计学意义(P>0.05).PDTC组大鼠肾损伤的病理变化较IRI大鼠明显减轻.结论 PDTC通过抑制NF-κB,有效减少IL-8,TNFα和iNOS的产生,对肾缺血再灌注有良好的保护作用.     

大鼠肾缺血-再灌注后JNK mRNA及蛋白表达的变化及银杏达莫注射液的干预作用

目的：观察JNK在肾缺血-再灌注损伤大鼠肾组织中的表达,研究银杏达莫注射液对肾缺血-再灌注损伤的防治作用。方法：将健康雄性SD大鼠50只随机分为5组：假手术对照组（n=10）,缺血-再灌注损伤模型组（n=10）,银杏达莫高剂量、中剂量、低剂量组（每组10只）。对于模型组、高、中、低剂量组,切除右肾,夹闭左侧肾蒂缺血1h,移去动脉夹再灌注1h,除此之外,对于银杏达莫处理组,手术前分别按每天0.9,1.8,3.6ml/kg的剂量尾静脉注射给药1周,假手术对照组和模型组手术前按每天1.8ml/kg的剂量尾静脉注射生理盐水,给药1周。检测肾组织丙二醛（MDA）含量、超氧化物歧化酶（SOD）的活性及血肌酐（Scr）、血尿素氮（BUN）的含量。取肾组织光镜、电镜下观察各组肾组织的形态学变化,用RT-PCR技术检测各组大鼠肾组织JNKmRNA的表达情况,Western印迹法观察p38MAPK、JNK的活化情况。结果：与假手术对照组相比,模型组大鼠Scr（214.2±40.1）μmol/L、BUN（8.75±1.28）mmol/L及MDA（11.27±2.43）nmol/mgprot含量均比假手术组增高（P〈0.01）,SOD（103.62±6.59）nmol/mgprot活性显著下降（P〈0.01）;肾组织JNKmRNA（1.38±1.36）水平显著升高（P〈0.01）;肾组织p-JNK蛋白水平显著上升,与模型组比较差异有统计学意义（P〈0.05）。银杏达莫注射液干预后,Scr、BUN及MDA含量显著降低,SOD活性显著升高;肾组织JNKmRNA水平显著下调,与模型组比较差异有统计学意义（P〈0.01）;肾组织p-JNK蛋白水平显著下调,与模型组比较差异有统计学意义（P〈0.05）;银杏达莫不同剂量组之间差异无统计学意义。结论：银杏达莫注射液可通过降低氧自由基水平、减轻脂质过氧化反应,从而下调JNKmRNA及蛋白表达水平以改善缺血-再灌注损伤大鼠肾功能,减轻其损伤程度。     

大鼠肾缺血再灌注损伤中ICAM-1表达的变化

目的:观察细胞间黏附分子-1(intercellular adhesion molecule-1,ICAM-1)在大鼠肾缺血再灌注(ischemia/reperfusion,I/R)不同时间点表达的变化并与肾功能恶化程度做相关性分析,从而探讨ICAM-1在肾I/R损伤中所起的作用.方法:应用苦味酸法和二乙酰一肟反应法测定大鼠肾I/R不同时间点血肌酐和尿素氮值, HE染色光镜下观察石蜡包埋切片肾组织损伤的形态学改变,免疫组化法分析ICAM-1在肾I/R不同时间点表达的变化.结果:肾功能检测发现, 再灌注1 h后血肌酐和尿素氮值开始增高和正常对照组比较有统计学差异(P＜0.05),12 h达峰值.HE染色光镜下观察肾组织细胞以近端肾小管变性、坏死为主,I/R各时间点肾组织病理损伤变化与肾功能变化规律相一致.再灌注后早期ICAM-1表达以内皮细胞为主,后期肾脏各部均可表达,小管上皮尤甚.肾脏表达的ICAM-1与肾功能恶化程度存在明显的正相关(P＜0.01).结论:I/R早期肾脏即有ICAM-1表达,其表达量与肾功能恶化程度呈正相关,提示ICAM-1在肾I/R损伤发病机制中起促进作用.     

氨基酸对大鼠肾缺血再灌注损伤bcl-2和HSP70表达影响的研究

目的：探讨8种L—支链氨基酸合剂对急性肾缺血—再灌注损伤的保护作用及作用机制。方法：夹闭大鼠双侧肾蒂45min，再灌注24h制成肾缺血再灌注损伤动物模型，将24只SD大鼠随机分为假手术组(A组)、对照组(B组)、氨基酸治疗组(C组)，通过检测尿量、血尿素氮(BUN)、血肌酐(Cr)，肾组织苏木精—伊红染色及用免疫组织化学进行bcl—2和HSP70表达检测。结果：3组肾组织中bcl—2和HSP70均有表达，但免疫反应强度不同。与A组相比，B组尿量增加，血BUN、Cr升高，肾小管上皮细胞呈现缺血性改变，HSP70表达明显增强，两组间差异有显著性意义，而bcl—2表达差异无显著性意义。与B组相比，C组尿量明显增加，血BUN、Cr明显下降，且缺血损伤程度有减轻，bcl—2表达明显增强，两组间差异有显著性意义，而HSP70表达差异无显著性意义。结论：该氨基酸合剂对大鼠急性肾缺血再灌注损伤有明显保护作用，其作用机制可能与它影响bcl—2表达有关。     

左卡尼汀对肾缺血再灌注损伤的抗氧化作用及其机制

目的研究左卡尼汀对大鼠肾缺血再灌注损伤的抗氧化作用并探讨其机制。方法将大鼠随机分为3组：对照组（C组）,缺血再灌注组（IR组）,左卡尼汀组（LC组）。C组不予缺血再灌注处理,IR组及LC组建立肾脏IR模型。再灌注6h后检测各组血清肌酐（Cr）和尿素氮（BUN）水平;测定肾组织超氧化物歧化酶（SOD）活性及丙二醛（MDA）含量;RT-PCR检测肾组织核因子E2相关因子2（Nrf2）、血红素氧化酶-1（HO-1）mRNA含量;Western-blot检测各组肾组织Nrf2及HO-1蛋白表达水平。结果 LC组血清Cr、BUN水平低于IR组[（74.17±12.80）μmol/L、（24.28±2.58）mmol/L vs.（112.83±17.45）μmol/L、（35.13±6.01）mmol/L],差异具有统计学意义（P〈0.01）。LC组肾组织SOD活性高于IR组[（39.55±6.61）kU/g vs.（28.05±4.37）kU/g],差异具有统计学意义（P〈0.01）;MDA显著降低于IR组[（4.15±0.69）μmol/g vs.（6.12±1.08）μmol/g],差异具有统计学意义（P〈0.01）。IR组Nrf2、HO-1mRNA及蛋白表达水平高于C组（P〈0.01）,低于LC组（P〈0.01）。结论左卡尼汀对肾脏缺血再灌注损伤具有明显保护作用,其机制可能为激活Keapl-Nrf2-ARE通路进而诱导HO-1的表达。     

α-硫辛酸对肾缺血再灌注损伤大鼠心肌细胞凋亡的影响

目的 评价α-硫辛酸对肾缺血再灌注损伤大鼠心肌细胞凋亡的影响.方法 健康雄性SD大鼠36只,体重250～280 g,采用随机数字表法,将其随机分为3组:假手术组(S组)、肾缺血再灌注组(I/R组)和α-硫辛酸组(L组),每组12只.I/R组和L组采用夹闭双侧肾动、静脉45 min后恢复灌注的方法制备大鼠肾缺血再灌注损伤模型,S组不夹闭双侧肾蒂.L组于夹闭前20 min和再灌注前20 min分别尾静脉注射α-硫辛酸30 mg/kg,I/R组分别尾静脉注射等容量溶剂(35％聚乙二醇+60％生理盐水+5％乙醇).于再灌注24h抽取腹主动脉血,测定血清肌酐(Cr)和MDA浓度,随后处死大鼠取心脏,测定心肌MDA含量和SOD活性,采用流式细胞术检测心肌细胞凋亡率,采用免疫组化法测定心肌细胞Bcl-2及Bax的表达,计算Bcl-2/Bax比值.结果 与S组相比,I/R组和L组血清Cr和MDA浓度、心肌MDA含量和心肌细胞凋亡率升高,SOD活性降低,I/R组Bcl-2/Bax比值降低(P＜0.05);与JR组相比,L组血清Cr和MDA浓度、心肌MDA含量和心肌细胞凋亡率降低,SOD活性升高,Bcl-2/Bax比值升高(P＜0.05).结论 α-硫辛酸可减轻肾缺血再灌注损伤大鼠心肌损伤,与抑制心肌细胞凋亡有关.     

臭氧氧化预处理对大鼠肾脏缺血再灌注损伤致细胞凋亡的影响

目的 观察臭氧氧化预处理对大鼠肾脏缺血再灌注损伤导致的细胞凋亡的影响.方法 分为3组进行实验:(1)假手术组:切除大鼠右肾,缝合腹壁;(2)缺血再灌注组:切除大鼠右肾后,夹闭左肾动、静脉45 min,然后开放;(3)臭氧氧化预处理组:手术步骤与缺血再灌注组相同,在术前15d开始经直肠吹入氧气和臭氧的混合气体5～5.5 ml(臭氧浓度为50 mg/L,1 mg·kg-1 ·d-1),应用至术前1d.全自动生化分析仪检测3组大鼠血清尿素氮和肌酐,比色法测定血清脂质过氧化产物丙二醛(MDA)和超氧化物歧化酶(SOD).免疫组织化学法检测大鼠肾细胞胞浆细胞色素C(CytC)的表达,蛋白质印迹法检测CytC的含量.逆转录聚合酶链反应法检测肿瘤坏死因子α(TNF-α)、白细胞介素-1β(IL-1β)和白细胞介素-6 (IL-6) mRNA的表达.结果 缺血再灌注和臭氧氧化预处理组血清尿素氮、肌酐和MDA均高于假手术组,而缺血再灌注组的尿素氮、肌酐和MDA又高于臭氧氧化预处理组.缺血再灌注组血清SOD低于假手术组和臭氧氧化预处理组(P＜0.05).臭氧氧化预处理组的肾组织病理学改变较缺血再灌注组轻.假手术组、缺血再灌注组和臭氧氧化预处理组的CytC表达灰度值分别为101.50±18.02、181.00±20.85和156.71±16.82,两两比较,差异均有统计学意义(P＜0.05).臭氧氧化预处理组肾细胞胞浆和线粒体中CytC含量较缺血再灌注组有所下降(P＜0.05).结论 臭氧氧化预处理可以减轻肾脏脂质过氧化反应,减少炎症因子的合成,抑制CytC的释放,减轻肾缺血再灌注损伤.     

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.     

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.