诱导H-2半相合小鼠骨髓受体获得免疫赦免的体内研究

目的通过Fas配体(FasL)-Fas途径清除异体骨髓移植(allo-BMT)物中针对受体主要组织相容复合物(MHC)的淋巴细胞,从而抑制受体发生移植物抗宿主病(GVHD).方法实验组(5组)用磁性细胞分离系统分离BALB/C小鼠(H-2d,雌性)早期造血细胞(HC),经逆转录病毒法转移外源mFasLcDNA基因并扩增1w后与BAC小鼠(H-2d×b,雄性)骨髓单个核细胞(BMMC)按0.625∶1混合培养1w,经尾静脉将5×106个混合细胞(0.5ml)注入经全身60Coγ照射的BALB/C小鼠.同时设立1组(空白对照组,未移植细胞);2组(同基因BMT组);3组(转染外源FasL的同基因BALB/CHC+正常BALB/C小鼠BMMC混合培养后移植组);4组(H-2单倍型不同小鼠的allo-BMT组).观察移植鼠的造血重建及细胞来源、GVHD、生存率和造血重建后的免疫学特征.结果BMT后+10d、+20d,实验组、3和4组的外周血白细胞、血小板计数均低于2组(P＜0.01),但+30d后以上各组则均恢复正常.实验组中存活2个月的8只BALB/C小鼠,其BMMC中供体来源Y染色体出现率为(81.14±5.3)%,其中1例脾细胞基因组DNA经PCR检出Neor和mFasLcDNA整合;各组移植2个月后的生存率为实验组80%、1组0%、2、3组均为100%、4组20%,经对数秩和检验Kaplan-Meier曲线,实验组总体生存期明显长于4组(P＜0.01).实验组和4组移植后死亡小鼠及4组存活2个月的小鼠肝脏、爪垫皮肤和小肠(回肠)组织切片大部分显示GVHDⅡ～Ⅲ度,而存活2个月的实验组小鼠组织切片则多显示GVHDⅠ度或无GVHD表现.BMT造血重建后,实验组的BALB/C小鼠脾细胞,与近交系供体BAC小鼠及BALB/C小鼠脾细胞混合培养均不显示增殖反应,但对无关Wistar大鼠脾细胞则仍显示明显的增殖反应.结论经逆转录病毒法基因转移并表达mFasL的受体HC,体外与异基因供体BMMC混合培养后移植,能使受体获得供体来源的造血重建,并明显降低GVHD发生,且无明显Fas+靶器官损害,延长了受体生存率.     

HSV-sr39TK-GCv/ACV系统抑制小鼠异基因骨髓移植后移植物抗宿主病

目的 研究突变型单纯疱疹病毒胸苷激酶一更昔洛韦/阿昔洛韦(HSV-sr39TK-GCV/ACV)系统对小鼠异基因骨髓移植后移植物抗宿主病(GVHD)的影响.方法 采用改良的磷酸钙沉淀法,以携带HSv-sr39TK基因的慢病毒感染C57BL/6小鼠的脾淋巴细胞.制得sr39TK+T淋巴细胞.以C57BL/6小鼠为供者,Balb/c小鼠为受者进行骨髓移植,受者移植前接受60>Coγ射线照射.实验分6组进行:(1)GCV组共30只小鼠,均于骨髓移植的同时输注sr39TK+T淋巴细胞.其中10只于骨髓移植当天至第6天腹腔注射GCV 0.5 mg/d,10只于骨髓移植后第7～13天腹腔注射GCV0.5 mg/d,10只于骨髓移植后第12～18天腹腔注射GCV 0.5 nag/d;(2)ACV组共30只小鼠,骨髓移植与sr9TK+T淋巴细胞输注同GCV组,其中10只于骨髓移植当天至第6天腹腔注射ACV 0.5mg/d,10只于骨髓移植后第7～13天腹腔注射ACV 0.5 mg/d,10只于骨髓移植后第12～18天腹腔注射ACV 0.5 mg/d;(3)移植对照组仅行骨髓移植;(4)脾细胞对照组行骨髓移植和脾淋巴细胞输注;(5)GCV对照组在脾细胞对照组的基础上于骨髓移植后第7～13天腹腔注射GCV 0.5 mg/d.(6)sr39TK对照组行骨髓移植和sr9TK+T淋巴细胞输注.观察各组受者的存活时间、GVHD的发生情况及程度.结果 GCV对照组、sr9TK对照组、睥细胞对照组和移植对照组小鼠均于骨髓移植后19 d内死亡.GCV组移植当天用药者、第7天用药者和第12天用药者的存活时间分别为(36.70±5.20)d、(40.30±4.69)d和(27.10±4.85)d.ACV组移植当天用药者、第7天用药者和第12天用药者的存活时间分别为(36.50±5.26)d、(46.20±3.61)d和(30.90±5.21)d.GCV组和ACV组受者的存活时间均长于4个对照组(P<0.01),GCV组和ACV组中第7天用药者的存活时间和5(1 d存活率优于其它各时间用药者,差异有统计学意义(P<0.05),而ACV组第7天用药者又明显优于GCV组第7天用药者(P<0.05).4个对照组小鼠移植后10～12 d均开始出现Ⅲ～Ⅳ级GVHD.GCV组和ACV组死亡小鼠可见Ⅱ～Ⅳ级GVHD.而该两组中长期存活受者仅有Ⅰ～Ⅱ级GVHD.结论 HSV-sr9TK-GCV/ACV系统对小鼠异基因骨髓移植后的GVHD有一定的抑制作用;ACV的效果优于GCV;移植后7 d时应用ACV的效果较佳.     

同种异基因造血干细胞移植急性移植物抗宿主病小鼠模型的制作

目的 制作同种异基因造血干细胞移植急性移植物抗宿主病(GVHD)小鼠模型.方法 以C57BL/6( H-2b)小鼠为供者,Balb/c( H-2d)小鼠为受者,进行同种异基因骨髓移植.设立全身照射(TBI)对照组(4只)、GVHD组(10只)、单纯骨髓移植组(10只)及正常对照组(4只).TBI对照组仅进行致死性TBI,TBI后不进行骨髓移植;GVHD组于TBI前5d开始饮用含320 mg/L庆大霉素和250 mg/L红霉素的饮用水,移植当天以60Co γ射线行一次性TBI,总剂量8.0Gy,TBI后5h内每只小鼠经尾静脉输注C57BL/6小鼠骨髓细胞2×106个+脾细胞1×107个;单纯骨髓移植组预处理与GVHD组相同,每只小鼠经尾静脉输注C57BL/6小鼠骨髓细胞2×106个.移植后观察小鼠的精神状态、活动能力、体位改变、皮毛、体重和大便等,记录每只小鼠的存活时间,计算存活率,并绘制生存曲线.濒死小鼠的皮肤、肝脏、小肠和骨髓行病理检查.结果 TBI对照组小鼠的存活时间为(9.0±0.7)d,GVHD组为(32.0±3.2)d,单纯骨髓移植组为(17.5±1.6)d,3组间两两比较,存活时间的差异均有统计学意义(P＜0.01).TBI对照组病理检查显示造血功能衰竭.GVHD组于移植后第10～13天出现急性GVHD表现,其皮肤、肝脏和小肠组织的病理表现均符合Ⅰ～Ⅱ度急性GVHD改变,单纯骨髓移植组也于移植后第10～13天出现GVHD表现,但其GVHD表现和组织学改变明显轻于GVHD组,仅为0～Ⅰ度GVHD.结论 Balb/c小鼠经致死性TBI后移植同种异基因小鼠骨髓细胞+脾细胞可成功制作稳定的急性GVHD模型.     

致敏供者淋巴细胞输注对受者免疫功能重建及移植物抗宿主病发生率的影响

目的探讨非清髓异基因外周血造血干细胞移植后致敏供者淋巴细胞输注(DLI)对受者免疫重建及移植物抗宿主病(GVHD)发生率的影响。方法以C57BL/6小鼠(H-2b)为受鼠, BALB/c小鼠(H-2d)为供鼠,建立异基因外周血造血干细胞移植模型(实验组),移植当天受者接受60Coγ射线全身照射,移植后第2天腹腔注射环磷酰胺200 mg/kg。以不行造血干细胞移植,仅行γ射线全身照射和环磷酰胺腹腔注射的正常C57BL/6小鼠为对照。实验组存活小鼠在移植后第28天分别接受致敏供鼠淋巴细胞输注(n=8)、未致敏供鼠淋巴细胞输注(n=8),另有6只不输注供鼠淋巴细胞。移植后检测受者异基因嵌合率,观察GVHD的发生情况以及T淋巴细胞亚群变化,并行供受者间以及供受者与第三方小鼠(昆明鼠)间的单向混合淋巴细胞反应。结果实验组受鼠SRY基因均为阳性,嵌合率为(30.881±3.962)%。DLI后,接受未致敏DLI者均出现不同程度的GVHD,死亡3只(7.5%,3/8),而接受致敏DLI者无明显GVHD及死亡者。移植后45 d,接受致敏DLI者的CD8 T淋巴细胞明显高于正常C57BL/6小鼠(P<0.05),而接受未致敏DLI者的CD8 T淋巴细胞与正常对照的差异无统计学意义(P>0.05),至移植后60 d,接受DLI者的T淋巴细胞亚群接近正常(P>0.05);对照组T淋巴细胞亚群持续低于正常对照(P<0.05)。实验组小鼠淋巴细胞对供者淋巴细胞刺激的反应性均下降(P<0.01),以接受致敏DLI者最明显,而对昆明鼠淋巴细胞刺激的反应性维持正常水平。结论造血干细胞移植后输注致敏供者的淋巴细胞能促进受者的免疫功能重建,并可减少GVHD的发生。     

骨髓间充质干细胞的输注时机对小鼠骨髓移植后急性移植物抗宿主病的影响

目的 探讨骨髓间充质干细胞(MSCs)输注时机对异基因骨髓移植(allo-BMT)后急性移植物抗宿主病(aGVHD)的影响及其机制.方法 以Babl/c小鼠为供者,于无菌条件下获取其骨髓,制成MSCs悬液及骨髓细胞悬液.C57BL/6小鼠为受者,经电子直线加速器行全身照射后,分为5组进行allo-BMT.骨髓移植组受者经尾静脉输注骨髓细胞悬液和RPMI 1640培养液各0.2 ml;联合移植组受者经尾静脉输注骨髓细胞悬液和MSCs悬液各0.2 ml;延迟输注Ⅰ组受者经尾静脉输注骨髓细胞悬液0.2 ml,3 d后再输注MSCs悬液0.2 ml;延迟输注Ⅱ组受者经尾静脉输注骨髓细胞悬液0.2 ml,7 d后再输注MSCs悬液0.2 ml;对照组受者经尾静脉输注RPMI 1640培养液0.4 ml.记录受者存活时间及aGVHD的发生情况,检测外周血白细胞、CD4+ 和CD8+淋巴细胞数,测定血清γ干扰素(IFN-γ)和白细胞介素4(IL-4)水平,观察死亡小鼠的肝、脾、小肠及皮肤等组织病理学变化.结果 对照组受者均于移植后14 d内死亡.骨髓移植组于移植14 d以后出现aGVHD的表现,且均于23 d内死亡.联合移植组aGVHD的发生率为30%,延迟输注Ⅰ组aGVHD的发生率为60%,两组受者的存活时间均长于骨髓移植组.延迟输注Ⅱ组与骨髓移植组间aCVHD发生率和死亡时间的差异无统计学意义.受者的白细胞数均于全身照射后3 d降至最低,各移植组白细胞数皆于移植后回升,但骨髓移植组和延迟输注Ⅱ组的白细胞数未能恢复至正常水平,而联合移植组和延迟输注Ⅰ组的白细胞数均于移植后28 d恢复正常.输入MSCs者,CD4+淋巴细胞数量明显升高,而CD8+淋巴细胞数量下降,以联合移植组最为明显.联合移植组的IFN-γ水平明显低于骨髓移植组,而IL-4水平高于骨髓移植组.各组发生aGVHD的小鼠的肝、脾、小肠及皮肤病理改变基本一致.结论 MSCs与骨髓同时输注时aGVHD的发生率最低,受者的存活时间也最长,其机制可能与细胞因子水平有关.     

基因工程Treg细胞对小鼠异基因骨髓移植后GVHD和GVL效应的影响

目的 探讨输注慢病毒载体介导的小鼠基因工程调节性T淋巴细胞(Treg细胞)对小鼠异基因骨髓移植后移植物抗宿主病(GVHD)及移植物抗白血病(GVL)效应的影响.方法 利用慢病毒载体介导,将小鼠叉状头螺旋转录因子(Foxp3)基因转导入Balb/c小鼠的CD4+CD25-T淋巴细胞,即为基因工程Treg细胞.以Balb/c小鼠为供者.C57BL/6小鼠为受者,进行异基因骨髓移植,移植当天受者接受X线直线加速器全身照射.用随机数字表法将受者分为5组,每组10只.(1)单纯照射组:经受者尾静脉输注RPMI 1640培养液0.2 ml;(2)白血病对照组:经受者尾静脉输注供者骨髓细胞5×106个+C57BL/6小鼠T淋巴细胞白血病/淋巴瘤细胞株(EL4细胞)500个;(3)移植对照组:经受者尾静脉输注供者骨髓细胞5×106个+脾细胞5×106个+EL4细胞500个;(4)工程Treg组:经受者尾静脉输注供者骨髓细胞5×106个+脾细胞5×106个+EL4细胞500个+基因工程Treg细胞5×106个;(5)空载体对照组:经受者尾静脉输注供者骨髓细胞5×106个+脾细胞5×106个+EL4细胞500个+空载体转导的CD4+CD25-T淋巴细胞5×106个.每天观察受者存活情况;记录GVHD及白血病的发生情况;各组均于小鼠濒死前取其肝脏、小肠、皮肤、脾脏等组织,进行病理学观察;取长期存活(超过60 d)受者的骨髓细胞,检测嵌合情况.结果 单纯照射组、白血病对照组、移植对照组、工程Treg组和空载体对照组小鼠存活时间分别为(10.3±1.5)d、(20.7±1.9)d、(26.0±4.3)d、(49.0±17.7)d和(24.4±4.1)d,工程Treg组小鼠存活时间明显长于其他各组,差异有统计学意义(P＜0.05).白血病对照组小鼠肝、脾组织病理切片均存在白血病细胞浸润表现,移植对照组及空载体对照组小鼠肝脏、皮肤和小肠病理切片存在GVHD病理改变,而工程Treg组长期存活小鼠各组织病理切片结构基本正常,未见GVHD及白血病细胞浸润病理表现,该组GVHD评分明显低于移植对照组及空载体对照组.结论 小鼠异基因骨髓移植时联合输注基因工程Treg细胞可有效减少GVHD的发生并保留GVL效应.     

供心体外转染腺病毒介导的CD40Ig融合基因延长小鼠移植心脏存活时间

目的探讨体外转染CD40Ig融合基因对小鼠移植心脏存活时间的影响。方法构建携带小鼠CD40胞外段和人IgGFc融合基因的重组腺病毒载体(AdCD40Ig),以BALB/c小鼠为供者,C57BL/6小鼠为受者,建立小鼠腹部异位心脏移植模型,实验组供心移植前在体外以AdCD40Ig灌注,转染CD40Ig基因,另设空载体转染对照组、非转染对照组和近交系对照组(供、受者均为近交系C57BL/6小鼠)。术后观察移植心的存活及移植物中炎症细胞浸润情况,采用酶联免疫吸附试验(ELISA)检测受者体内CD40Ig融合蛋白表达情况,流式细胞仪检测受者体内产生γ干扰素(IFN-γ)的脾细胞。结果实验组移植心的存活时间达(15.8±0.7)d,明显长于空载体转染对照组和非转染对照组(P<0.01)。术后第2d,实验组受者体内CD40Ig融合蛋白表达最高,1周后明显降低。术后第7d,实验组移植心组织中浸润的炎症细胞明显比未处理对照组和空载体对照组少。实验组产生IFN-γ的CD4+和CD8+T淋巴细胞分别为(2.18±0.16)%和(10.82±0.74)%,与近交系对照组接近,明显低于未处理对照组和空载体对照组(P<0.01)。结论供心体外转染CD40Ig融合基因可有效抑制移植后受者体内同种T淋巴细胞的增殖,并延长移植心的存活时间。     

粒细胞集落刺激因子减轻小鼠混合骨髓移植后移植物抗宿主病的实验研究

目的探讨同基因骨髓混合一定比例粒细胞集落刺激因子(G-CSF)动员的异基因骨髓移植能否减轻急性移植物抗宿主病(aGVHD).方法将BALB/c与BCF1(BALB/c×C57BL/6)小鼠或与G-CSF动员BCF1小鼠脾细胞按一定比例混合,腹腔注入BALB/c幼鼠,制备新生小鼠GVHD模型,结果以脾指数表示.成年雌性BALB/c小鼠接受60Co全身照射8.5Gy后进行移植,移植物为BALB/c与雄性BCF1或与G-CSF动员BCF.小鼠骨髓细胞按一定比例的混合,移植细胞总数60×105个/只.观察移植小鼠aGVHD典型症状、病理表现及存活率.ELISA法测定细胞因子含量,流式细胞术分析T细胞亚群变化.结果(1)注射BALB/c与BCF1小鼠脾细胞混合比例为21、11及异基因BCF1小鼠脾细胞的新生小鼠均发生GVHD;但G-CSF动员与否,GVHD发生程度差异有统计学意义.(2)21及11混合骨髓移植(MBMT)组小鼠有中到重度GVHD表现;经G-CSF动员的MBMT组小鼠8周存活率较未动员组明显提高(P＜0.05).(3)G-CSF动员供鼠后L3T4+细胞下降显著,L3T4+/Lyt2+比值明显低于未动员组(P＜0.01).(4)G-CSF动员供鼠后混合淋巴细胞反应(MLR)细胞培养上清中,IL-2、IFN-γ水平降低,IL-4水平升高.结论同基因骨髓混合一定量H-2半相合异基因骨髓移植可减轻GVHD的发生;G-CSF动员供鼠可进一步减轻MBMT后GVHD的发生.其机理可能与IL-2、IFN-γ下降、IL-4升高有关.     

造血干细胞在皮肤移植中诱导特异性免疫耐受的研究

目的 探讨造血干细胞在皮肤移植中诱导特异性免疫耐受的作用和地位；尝试建立一种简单、有效且实用的耐受诱导方案。方法 采用小鼠皮肤移植模型；通过免疫磁珠法负筛选系统提取供者骨髓中的造血干细胞。给低剂量放射线全身照射的BALB／C小鼠管饲CsA 50mg／kg，接着经尾静脉推注冷藏的C57BL／6小鼠的造血干细胞或骨髓细胞，并当天完成C57BL／6小鼠→BALB／C小鼠的皮肤移植。记录皮肤存活时间并于30d后对受者小鼠作混合淋巴细胞反应(MIR)和迟发超敏反应(DTH)检查。结果 经处理的BALB／C小鼠移植皮肤存活时间延长；MLR和DTH检查证明BALB／C小鼠对C57BL／6小鼠的抗原生产了特异性耐受，但对无关第三者KM小鼠的抗原仍表现出强烈的免疫应答。输注骨髓细胞和造血干细胞的两个方案差异无显著性。结论 利用C57BL／6小鼠的造血干细胞在BALB／C小鼠体内成功诱导出了供者特异性的移植耐受；输注骨髓细胞和造血干细胞的两个方案差异无显著性。     

Tju103和CTLA4-Ig联合诱导主要组织相容复合物半相合小鼠骨髓移植耐受

目的观察吲哚亚甲基异烟腙(Tju103)和细胞毒性T淋巴细胞相关性抗原4免疫球蛋白(CTLA4-Ig)联合应用，对主要组织相容复合物(MHC)半相合小鼠骨髓移植的植入以及移植后移植物抗宿主病(GVHD)、移植物抗白血病(GVL)和抗感染的影响；探索一条既能降低GVHD能保留GVL和抗感染能力的移植途径。方法体外以受者(正常CB6F1鼠，H-2^bd)抗原为特异性免疫耐受诱导原，MHC半相合的供者(C57BL／6鼠，H-2^b)T淋巴细胞经和Tju103、CTLA4-Ig共育后，与供者骨髓细胞混合输入经预处理的受者体内。观察Tju103和CTLA4-Ig联合作用对移植后造血重建、GVHD、GVL和抗感染的影响。结果单纯照射组(A组)：全部(10只)白血病小鼠于照射后11d内死于造血功能衰竭，大部分(8只)死于照射后4～7d。环磷酰胺(CTX)治疗组(B组)：全部(10只)小鼠于接种白血病细胞后16～23d(移植后11～18d)死于白血病，但CTX治疗延长了白血病小鼠存活期。单纯移植组(C组)：全部(10只)小鼠于移植后21d内死亡，均死于GVHD。CsA预防组(D组)：4只小鼠于移植后8～22d内死亡，其中1只死于白血病，2只死于感染，1只死于GVHD；6只存活超过30d。Tju103处理组(E组)：4只小鼠于移植后9～26d内死亡，其中1只死于白血病，1只死于感染，2只死于GVHD；6只存活超过30d。CTLA4-Ig处理组(F组)：3只小鼠于移植后14～23d内死亡，其中1只死于感染，2只死于GVHD；7只存活超过30d。Tju103 CTLA4-Ig处理组(G组)：仅1只小鼠于移植后第19d死于GVHD；9只存活超过30d。结论CsA、Tju103或CTLA4-Ig单独处理均可以明显延长小鼠移植后生存期，降低GVHD的发生和程度；CTLA4-Ig有抗感染和GVL作用，而Tju103和CsA则没有此作用；CTLA4-Ig和Tju103两者联合处理供者T淋巴细胞对延长受者生存期和降低GVHD作用更明显。     

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.     

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.     

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.     

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.     

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.     

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.     

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.     

Systemic analgesia adapted to the children's condition

A concept of balanced analgesia using nonsteroidal anti-inflammatory drugs (NSAIDs), paracetamol (acetaminophen), opioids, and corticosteroids can also be used in patients with pre-existing illnesses. NSAIDs are the most effective treatment for acute pain of moderate intensity in children; however, these drugs should be avoided in patients at increased risk for serious side effects, e.g. patients with renal impairment, bleeding tendency, or extreme prematurity. NSAIDs can be given with minimal risks to the younger child with mild to moderate asthma, and, in these patients, the use of steroids can be encouraged; in addition to their antiemetic and analgesic action, a beneficial effect on asthma symptoms can be expected. In the non-intubated child with cerebral trauma, exaggerated sedation caused by opioids and increased bleeding tendency caused by NSAIDs must be avoided. In neonates and small infants, the oral administration of sucrose or glucose is helpful to minimize pain reaction during short uncomfortable interventions.