未成熟树突状细胞的制备及其免疫学特性

近年来,树突状细胞(dendritic cells,DCs)诱导免疫耐受成为研究的热点(1-2).成熟树突状细胞(mDCs)能激活T淋巴细胞诱导免疫应答,未成熟树突状细胞(imDCs)虽不能活化T淋巴细胞,但具有强大的抗原摄取及处理能力,可导致T淋巴细胞无能,利于免疫耐受的维持[3-4].借此特性可为同种异体复合组织移植(composite tissue allotransplantation,CTA)排斥反应寻求有效特异的防治新手段.本实验应用大鼠骨髓前体细胞在细胞因子的诱导下培养分离imDCs,进行CTA局部免疫耐受作用的模拟研究.     

结肠抗原特异性T细胞克隆回输治疗大鼠溃疡性结肠炎的研究

目的　探讨结肠抗原特异性T细胞克隆回输治疗溃疡性结肠炎大鼠的作用。方法将结肠抗原特异性T细胞克隆回输至 2 0只溃疡性结肠炎大鼠 ,观察刺激指数 (SI)、CD 4、CD 8以及CD4 CD2 5 T细胞和白细胞介素 13和白细胞介素 4水平的变化 ,并对照治疗前后结肠病变情况。结果　克隆回输后结肠炎症吸收 ,症状基本消失。回输前SI平均值为 8.15± 2 .2 4,回输后为2 .0 2± 0 .87;CD 4、CD 8水平、CD 4/CD 8比值、IL 13和IL 4水平呈明显下降 ,CD4 CD2 5 调节性T细胞水平 (% )明显升高 (16.5± 3 .8Vs 45 .4± 4.9) ,差异有显著性 (P <0 .0 5 )。结论　结肠抗原特异性T细胞克隆回输 ,成功诱导溃疡性结肠炎大鼠进入特异性免疫耐受状态 ,CD4 CD2 5 调节性T细胞可能参与耐受机制     

CpG寡聚脱氧核苷酸增强树突状细胞疫苗诱导的特异性抗前列腺癌作用

目的 观察CpG寡聚脱氧核苷酸(CpG-ODN)对截短的人前列腺特异性膜抗原(tPSMA)基因修饰的树突状细胞(DCs)诱导的抗前列腺癌效应.方法 利用复制缺陷性腺病毒AdEasy-1系统,通过基因重组技术构建Ad-tPSMA及Ad-eGFP.将Ad-tPSMA和Ad-eGFP感染鼠源性DCs,用含10μg/L粒细胞-巨噬细胞集落刺激因子(GM-CSF)、白细胞介素(IL)-4和含10%胎牛血清(FCS)的RPMI 1640培养基诱导培养6 d后,然后再添加1 mg/L的CpG-ODN体外培养1 d,最后添加1 mg/L的脂多糖(LPS)继续培养1 d,使其成熟.流式细胞仪检测DCs细胞表型,CCK-8法检测混合淋巴细胞反应T细胞增殖能力,酶联免疫吸附试验(ELISA)试剂盒检测T细胞分泌细胞因子[IL-2、干扰素(INF)-γ]的影响,CCK-8试剂检测T细胞特性杀伤靶细胞活性.结果 CpG-ODN促进Ad-tPSMA感染的DCs(CpG/DCs-Ad-tPSMA)高表达MHC Ⅱ(83.8±3.7)%、CD80(79.8±5.6)%和CD86(78.3 ±2.8)%,且刺激同种异体T细胞增殖能力明显高于DCs-Ad-tPSMA组、DCs-Ad-eGFP组和未转染的DCs组(P＜0.05);培养上清中细胞因子IL-2(179.64±2.72)ng/L和INF-γ(1581.75±28.61)ng/L,表达水平均明显高于DCs-Ad-tPSMA组、DCs-Ad-eGFP组和未转染的DCs组(P＜0.05);CpG/DCs-Ad-tPSMA组诱导RM-1-tPSMA细胞特异性杀伤率为(55.3±1.2)%,明显高于DCs-Ad-tPSMA组(40.7±1.4)%、DCs-Ad-eGFP组(12.7±1.2)%和未转染的DCs组(10.8±1.7)%(P＜0.05).结论 CpG-ODN能增强PSMA基因修饰的DCs疫苗诱导的特异性抗前列腺癌效应.

Abstract：

Objective To observe cytosine-phosphorothioate-guanine oligodeoxynucleotides (CpG-ODN) for the anti-prostate cancer effect induced by dendritic cells (DCs) transduced with recombinant adenovirus vector bearing truncated human prostate specific membrane antigen (tPSMA) gene. Methods Replication deficient adenovirus AdEasy-1 system was used to construct recombination adenovirus Ad-tPSMA and Ad-eGFP. Mouse derived DCs were transduced with Ad-tPSMA and Ad-eGFP, and cultured for 6 days in the presence of 10 μg/L GM-CSF and IL4 in RPMI 1640 containing 10% FCS. After culture with 1 mg/L CpG-ODN for 1 day, DCs were further matured with lipopolysaccharide (LPS) at a concentration of 1μg/L for 1 day. The phenotype of DCs was analyzed by using flow cytometry. T cells proliferation stimulated by DCs in allogeneic mixed lymphocyte reactions and the level of interleukin (IL)-2, interferon (IFN)-γ were detected by ELISA kit, and cytotoxic CTL activity induced by DCs was tested by CCK-8 assay. Results CpG-ODN up-regulated the expression of MHCⅡ (83. 8 ±3. 7)% , CD80 (79. 8 ±5. 6)% and CD86 (78. 3 ±2. 8)% in Ad-tPSMA-tranduced DCs (CpG/DCs-Ad-tPSMA). T cells proliferation stimulated by CpG/DCs-Ad-tPSMA was significantly higher than that in DCs control group, DCs-Ad-tPSMA group and DCs-Ad-eGFP group (P ＜0.05). CpG/DCs-Ad-tPSMA induced increased IL-2 (179. 64 ±2. 72) ng/L, and INF-7 (1581.75 ±28. 61) ng/L expression levels as compared to DCs control group, DCs-Ad-tPSMA group, and DCs-Ad-eGFP group (P＜0. 05), and induced more outstanding RM-1-tPSMA cell specific cytotoxic rate (40.7 ±1.4)%than DCs control group (10. 8 ± 1.7) % , DCs-Ad-tPSMA group (40.7 ± 1.4)% , and DCs-Ad-eGFP group (12.7 ± 1. 2)% (P＜0.05). Conclusion CpG-ODN can promote specific anti-prostate cancer induced by DCs modified with recombinant adenovirus vector bearing tPSMA gene.     

胃癌抗原特异性树突状细胞疫苗的抗瘤效应

我们利用液氮冻融提取胃癌细胞抗原刺激小鼠骨髓来源树突状细胞(DCs)制备肿瘤疫苗,进而诱导小鼠脾脏淋巴细胞制备肿瘤抗原特异细胞毒性淋巴细胞(CTLs) ,应用于胃癌裸小鼠皮下模型,探讨其多方面抗胃癌效应。一、材料与方法1.BALB/c小鼠骨髓DCs肿瘤疫苗制备:依据文献[1] ,分离BALB/c小鼠股、胫骨骨髓细胞,经1g/L浓度SCG790 1肿瘤可融性抗原孵育过夜后,终浓度5 0 μg/L的粒细胞 巨噬细胞集落刺激因子(GM CSF)及10 0 μg/L的白细胞介素(IL) 4(PeproTech公司)诱导培养7d获得DCs肿瘤疫苗。抗CD40 FITC、抗CD80 FITC直标荧光…     

转Survivin基因树突状细胞抗消化道肿瘤的免疫效应研究

目的　研究转染Survivin的树突状细胞 (DC)在体外诱导高效而特异的抗消化道肿瘤免疫效应。方法　用脂质体作为介质 ,将Survivin基因转染入DC ,用Westernblot法检测培养上清Survivin的表达 ,检测这种DC分泌细胞因子白介素 (IL 12 )、肿瘤坏死因子 (TNF) α的功能 ,以及表面分子CD1a、CD83、MHcⅡ、CD80、CD86表达的高低 ,用MTT法诱导人特异的细胞毒性T淋巴细胞 (CTLs)的能力。结果　培养上清中均可以检测到Survivin表达 ;转基因DC的上清IL 12、TNF α两种细胞因子含量为 (2 65 .2± 3 2 .7)ng/L和(4 3 7.1± 83 .5 )ng/L明显比单纯DC组高(P <0 .0 5 ) ;转基因DC表面高表达CD1a、CD83、MHCⅡ、CD80、CD86;转基因的DC提呈的T细胞对胃癌细胞、结肠癌细胞、胆管癌细胞杀伤率分别为 :65 %、77%、85 % ,而未修饰的单纯DC杀伤作用较低。结论　Survivin基因转染修饰的DC能诱导细胞毒性T淋巴细胞的特异性 ,显著地提高DC的抗原提呈功能 ,体外能诱导高效而特异的抗癌免疫效应。     

反义bcl-2基因的表达诱导癌细胞凋亡致敏树突状细胞的研究

目的 探讨bcl-2基因与癌细胞的关系，建立反义bcl-2基因的逆转录病毒表达载体诱导癌细胞凋亡致每从人外周血诱导扩增的树突状细胞（DC s)的方法。方法 从正常人外周血分离获得单核细胞，加入50μg/L、1000U/L白细胞介素（IL）－4，隔日1次，共4次，培养第3天，加入反义bcl-2表达诱导凋亡的胆管癌细胞，再继续体外培养4d后，用树突细胞富集柱收集DCs。结果DCs高表达共刺激分子B7和CD1a，表面具有典型不规则突起，反义bcl-2表达诱导癌细胞凋亡形态的凋亡小体被DCs捕捉、吞噬，负载抗原的DCs其激发同种异体T淋巴细胞增殖的能力进一步增强。结论 反义bcl-2表达诱导癌细胞凋亡可以致敏rhGM-CSF加rhIL-4 从人外周血单核细胞诱导、扩增出的DCs，DCs可以有效提呈凋亡胆管癌细胞的抗原，可望成为有效的肿瘤抗原致敏DC的新途径。     

抗原负载的树突状细胞体外诱导抗肿瘤免疫的研究

目的 观察抗原负载的树突状细胞(DCs)体外诱导抗肿瘤免疫效应,探讨树突状细胞肿瘤疫苗的制备方法 .方法 以细胞因子粒细胞-巨噬细胞集落刺激因子(GM-CSF)和白细胞介素(IL)-4体外诱导人单核细胞来源的树突状细胞,第6天加入肝癌细胞BeL-7402的冻融抗原并以联合细胞因子鸡尾酒法[肿瘤坏死因子(TNF-α)+IL-6+IL-1β+前列腺素E2(PGE2)]诱导成熟,对照组仅以鸡尾酒法诱导成熟.24 h后收获DCs以流式细胞仪检测其成熟表型CD80、CD83、CD86和LHA-DR,酶联免疫吸附试验(ELISA)法检测其IL-12的分泌,噻唑蓝(MTT)比色法检测其刺激淋巴细胞增殖活性,乳酸脱氢酶释放实验检测其诱导的免疫效应细胞对肝癌细胞的特异性细胞毒作用.结果 联合细胞因子可诱导的DCs成熟和IL-12的分泌(P＜0.05),成熟的DCs有较强的刺激淋巴细胞增殖能力;抗原负载组DCs可诱导效应细胞对肝癌细胞BeL-7402的特异性杀伤作用(P＜0.05).结论 抗原负载的DCs可体外诱导特异性抗肿瘤免疫效应,提示以抗原负载的树突状细胞作为肿瘤免疫治疗的方法 是可行的.     

GW5074对不成熟树突状细胞诱导初始性CD4+T淋巴细胞分化为Treg的影响

目的 建立一种稳定且高效的不成熟树突状细胞(imDC)体外培养方法,探讨细胞外信号调节激酶(ERK)1/2信号传导通路抑制剂GW5074对imDC体外诱导同种初始性CD4+T淋巴细胞分化为调节性T淋巴细胞(Treg)的影响.方法 从健康成人外周血单个核细胞(PBMC)中分离、培养成熟树突状细胞(mDC)和imDC,并对mDC和imDC的免疫表型和功能进行鉴定.取新生儿脐静脉血分离初始性CD4+T淋巴细胞.实验分为5组:(1)空白对照组为单纯培养的初始性CD4+T淋巴细胞,不做任何处理;(2)阳性对照组将imDC与初始性CD4+T淋巴细胞以1∶10的细胞比例混合培养;(3)低浓度GW5074组;(4)中浓度GW5074组;(5)高浓度GW5074组.后3组在阳性对照组基础上,分别加入终浓度为8、24和40μmol/L的GW5074.培养5 d后,用流式细胞仪检测初始性CD4+T淋巴细胞转化为Treg细胞的转化率.结果 imDC呈CD1a高表达,CD80和CD83低表达;mDC呈CD1a低表达,CD80和CD83高表达.imDC和mDC的刺激指数分别为1.12±0.03、2.85±0.07.空白对照组,阳性对照组,低、中及高浓度GW5074组的CD4+CD25+Treg转化率分别为(5.81±1.36)%、(35.73±2.07)%、(22.53±2.11)%、(11.55±1.73)%和(4.97±1.83)%,除空白对照组与高浓度GW5074组间的差异无统计学意义(P＞0.05)外,其余各组之间两两比较,差异均有统计学意义(P＜0.01).结论 通过应用重组人粒细胞-巨噬细胞集落刺激因子和重组人白细胞介素4联合诱导人外周血PBMC可获得高纯度imDC,ERK1/2信号传导通路在诱导免疫耐受中发挥作用,GW5074可抑制初始性CD4+T淋巴细胞向Treg转化.

Abstract：

Objective To establish a stable and efficient method of culturing imDCs in vitro,and to explore the effect of GW5074, which blocks ERK1/2 signal pathway in the process of imnature dentritic cells (imDCs) on inducing differentiation of the na(i)ve allogeneic CD4+ T cells into Treg cells in vitro. Methods The imDCs and mature DCs (mDCs) were isolated and cultured from the peripheral blood mononuclear cells (PBMC) derived from a healthy adult male volunteer, and they were identified by cell morphology, cell surface marker and cell functions respectively. Na(i)ve CD4+ T cells were isolated from newborn umbilical vein blood and were divided into 5 groups to be cultured: (1) Blank control group: Na(i)ve CD4+ T cells were cultured alone;(2) Positive control group: The irrDCs were Middle-concentration GW5074 group;(5) High-concentration GW5074 group. In the last three groups, imDCs and na(i)ve CD4+ T cells were co-cultured, the same as the positive control group, but these groups were added by GW5074 dilution at the concentrations of 8, 24, and 40μmol/Lrespectively. After co-culture for 5 days, the transformation ratio from naive CD4+T cells to Treg T cells was detected by flow cytometry. Results On the surface of imDCs, there was stronger pression of CD1a, but weaker expression of CD80 and CD83. On the contrary, on the surface of mDCs, there was weaker expression of CD1a, but stronger expression of CD80 and CD83. The stimulation index in imDCs group and mDCs group was 1.12±0.03 and 2.85±0. 07 respectively. The transformation ratio of Treg T cells in blank control group, positive control group, low-concentration GW5074 group, middle-concentration GW5074 group and high-concentration GW5074 group was (5. 81±1.36)%, (35.73±2.07)%, (22.53±2.11)%, (11.55±1.73)%, and (4.97±1.83)%respectively. One-way ANOVA analysis revealed that there was no significant difference between high-concentration GW5074 group and blank control group, P＞0. 05, but significant difference between the remaining groups, P＜0.01. Conclusion High purity of imDCs can be obtained from PBMC by induction with rhGM-CSF and rhIL-4. ERK1/2 signal pathway plays a role in inducing the immune tolerance. GW5074 can inhibit differentiation of na(i)ve CD4+ T cells into Treg T cells.     

调节性CD4~+CD25~+T细胞的分离纯化及免疫功能研究

目的 制备调节性CD~+ CD25~+T细胞(Treg)分析其免疫功能,诱导局部免疫耐受防治同种异体复合组织移植(CTA)排斥反应.方法 采用免疫磁珠法(MACS)从雄性大鼠脾脏细胞分离CD4~+CD25~+Treg(1×10~6),2%锥虫蓝染色检测活性、流式细胞术分析其纯度,在5 mg/L抗CD3的刺激下观察其反应性、增殖及其与200 U/ml细胞介素(IL)-2的关系.结果 从8只雄性大鼠脾脏分选出的CD4~+CD25~+Treg活性平均为(97.90±0.36)%及纯度为(96.05±0.41)%,CD3刺激呈低反应,按比例培养抑制率为89%,IL-2可使CD4~+CD25~-抑制逆转.结论 MACS能快速分选出较高纯度的CD4~+CD25~+Treg,并且活性良好在体外具有免疫无能及免疫抑制作用,能满足动物CTA排斥反应研究的需要.     

RNAi对大鼠T淋巴细胞CD28和OX40基因表达的联合抑制作用

目的 通过RNAi技术干扰T细胞CD28、CD134基因表达后,诱导获得抑制性T细胞(Ts);探讨Ts免疫学特性.方法 设计针对目标基因的siRNA,转染大鼠T淋巴细胞,FCM检测CD28、CD134水平,混合淋巴细胞反应(MLR)检测转染后的T淋巴细胞对异体淋巴细胞的增殖能力的影响,逆转录-聚合酶链反应(RT-PCR)及酶联免疫吸附试验(ELISA)法检测细胞因子水平.结果 siRNA转染大鼠T淋巴细胞后,抑制CD28、CD134分子的表达,siRNA转染24 h后,siRNA组CD28、CD134表达受到抑制[转染后及转染前表达分别为(22.35±4.37)%及(34.76±3.51)%(P<0.05)],T淋巴细胞分泌细胞因子IL-10水平增高,转染组及未转染组表达分别为(77.15±12.60)ng/L及(37.56±5.93)ng/L(P<0.01).而转染组及未转染组的IL-2表达分别为(2.79±0.51)及(4.35±1.11)ng/L(P<0.05);干扰素(IFN)-γ表达分别为(277.15±14.8)、(682.7±53.5)ng/L(P<0.05).结论 siRNA可以特异性抑制大鼠T淋巴细胞共刺激分子CD28、CD134基因表达,抑制了IL-2、IFN-γ的表达,提高了IL-10细胞因子表达水平,从而产生了免疫耐受效应.Ts细胞具有抗原特异性,而且在外源性rrIL-2存在时,不能逆转Ts细胞的功能.     

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.