输注鼠基因工程Treg细胞抑制小鼠异基因骨髓移植后移植物抗宿主病

目的 探讨输注慢病毒载体介导的鼠基因工程调节性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)的影响.方法 利用慢病毒载体介导,将鼠又状头螺旋转录因子(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,实验分4组进行:(1)工程Treg组经受鼠尾静脉输注供鼠骨髓细胞5×10~6个+脾细胞5×10~6个+基因工程Treg细胞5×10~6个;(2)移植对照组经受鼠尾静脉输注供鼠骨髓细胞5×10~6个+脾细胞5x10~6;(3)单纯照射组经受鼠尾静脉输注RPMI 1640培养液0.2ml;(4)空载体对照组经受鼠尾静脉输注供鼠骨髓细胞5×10~6个+脾细胞5×10~6个十空载体转导的CD4~+ CD25~-T 淋巴细胞5×10~6个.每天观察受鼠存活情况;记录GVHD的发生情况;各组均于小鼠濒死前取其肝脏、小肠、皮肤等组织,进行病理学观察;取长期存活(超过60d)的受鼠骨髓细胞,检测嵌合情况.结果 单纯照射组、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(8.8±0.6)d、(36.7±2.5)d、(51.6±4.0)d和(34.1±2.3)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).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均存在GVHD病理改变,工程Treg组长期存活小鼠的肝脏、皮肤和小肠常规病理切片结构基本正常,未见GVHD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,减轻其严重程度.     

Ly49A转基因淋巴细胞对异基因骨髓移植后GVHD和GVL的影响

目的　观察Ly49A基因转染淋巴细胞对异基因骨髓移植后移植物抗宿主病 (GVHD)和移植物抗白血病效应 (GVL)的影响。方法　经逆转录病毒介导将Ly49A基因转染至C57BL/ 6小鼠的淋巴细胞 ,以C57BL/ 6(H 2 b)小鼠为供者 ,以接种EL961 1红白血病细胞的BALB/c(H 2 d)小鼠为受者 ,进行脾淋巴细胞和骨髓细胞联合移植 ,建立异基因急性GVHD模型 ,观察Ly49A基因转染的淋巴细胞对GVHD和GVL的影响。结果　在未进行移植的单纯照射组 ,小鼠的存活时间为 (6 .50±2 .41 )d ;仅以环磷酰胺治疗的小鼠存活时间为 (2 0 .90± 2 .88)d ;非转染淋巴细胞和骨髓细胞联合移植组的存活时间为 (1 7.1 0± 4 .65)d ;空载体转染淋巴细胞和骨髓细胞联合移植组的存活时间为(1 7.40± 5 .32 )d ;Ly49A转染淋巴细胞与骨髓细胞联合移植组的存活时间为 (35 .2 0± 1 2 .52 )d ,较上述各组明显延长 (P =0 .0 0 0 )。结论　Ly49A基因转染的淋巴细胞在异基因骨髓移植模型上具有一定程度的降低GVHD并保留GVL的作用     

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.     

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。     

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.     

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.     

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.     

输注供者自然杀伤细胞对小鼠单倍型相合造血干细胞移植的影响

目的 探讨输注供者自然杀伤(NK)细胞对小鼠单倍型相合造血干细胞移植的影响.方法 选取C57BL/6(H-2b)雄性小鼠为供者、CB6F1(H-2d/b)雌性小鼠为受者.移植前制备供者的骨髓细胞(BMC)、脾细胞(SC)及脾NK细胞,NK细胞经体外培养扩增和激活;所有受者均接受直线加速器X线全身照射(TBI)预处理.TBI后将受者分为4组(每组10只),分别进行单倍型相合造血干细胞移植.单纯TBI组:TBI后不输注细胞,仅作为对照;单纯BMC输注组:输注5×106个BMC;诱发GVHD组:输注5×106个BMC+1.5×107个SC;NK细胞输注组:输注5 x 106个BMC+1.5×107个SC+1×107个NK细胞,并腹腔注射100 ng重组人白细胞介素2(rhIL-2)和1μg rhIL-15,持续7 d.移植后观察各组受者GVHD的发生情况,并对各组受者进行组织病理学、供者细胞嵌合度和免疫功能重建等检测.另取TBI后受者20只,设白血病复发组和白血病治疗组,每组10只.白血病复发组:输注5×106个BMC+1×107个SC+2×106个白血病细胞株EL9611;白血病治疗组:在白血病复发组的基础上再输注1 x 107个NK细胞,并腹腔注射100 ng rhIL-2和1μg rhIL-15,持续7 d.观察两组受者白血病复发情况和移植后100 d的存活率.结果 单纯BMC输注组受者无GVHD发生,NK细胞输注组受者GVHD的评分和组织病理学改变均较诱发GVHD组轻(P<0.05)f诱发GVHD组的免疫功能重建较NK细胞输注组延迟.白血病复发组和白血病治疗组移植后100 d的存活率分别为20%和90%,两组比较,差异有统计学意义(P<0.01).结论 输注激活的供者NK细胞可以减轻小鼠单倍型相合造血干细胞移植后的GVHD,减少白血病复发,促进免疫功能重建.     

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.     

白细胞介素4在输注供体肝脏非实质细胞诱导免疫耐受中的作用

目的　探讨皮肤移植受体在输注供体肝脏非实质细胞 (NPC)诱导免疫耐受过程中 ,白细胞介素 4(IL 4)所起的作用。方法　将 2× 1 0 7个C3H/He (C3H)小鼠的肝脏非实质细胞通过尾静脉输入C57BL/ 6(B6)小鼠的体内 ,48h后B6小鼠腹腔注射环磷酰胺 2 0 0mg/kg ,1 8d后接受C3H小鼠皮片的移植 ,分别于NPC细胞输注前及输注后 7、1 8、30、60d采血监测IL 4水平的动态变化。结果　 1 5只接受皮片移植的小鼠 ,其皮片存活时间显著延长 ,皮片平均存活时间 (70± 1 7.2 )d ,正常对照组其移植皮肤的平均存活时间仅 (1 0± 0 .4)d ,用Elisa法检测NPC输注后不同时期IL 4水平的动态变化发现 ,B6小鼠体内血清IL 4水平逐渐升高 ,在长期耐受的小鼠中 ,其水平增加尤其显著 ,甚至成倍的提高。结论　IL 4水平的升高对于诱导和保持免疫耐受起着重要的作用     

Vasopressor hormone response following mesenteric traction during major abdominal surgery

Background : We investigated the vasopressor hormone response following mesenteric traction (MT) with hypotension due to prostacyclin (PGI₂) release in patients undergoing abdominal surgery with a combined general and epidural anesthesia. Methods : In a prospective, randomized, placebo-controlled study we administered 400 mg ibuprofen (i.v.) in 42 patients scheduled for abdominal surgery. General anesthesia was combined with epidural anesthesia (T4-L1). Before as well as 5, 15, 30, 45, and 90 min after MT we recorded plasma osmolality, hemodynamics and measured 6-keto-PGFlα (stabile metabolite of PGI₂), TXB₂ (stabile metabolite of thromboxane A₂) active renin, and arginine vasopressin (AVP) plasma concentrations by radioimmunoassay. Catecholamine levels were assessed by high-pressure liquid chromatography (HPLC) with electrochemical detection. Results : Following MT, arterial hypotension occurred along with a substantial PGI₂ release. This was completely abolished by ibuprofen administration. Although plasma levels of 6-keto-PGF_1α (1133 (708) vs. 60 (3) ng/L, median (median absolute deviation), P=0.0001, placebo vs. ibuprofen) remained significantly elevated, blood pressure was restored within 30 min after MT in the placebo group. At the same point in time plasma concentrations of TXB² (164 (87) vs. 58 (1) ng/L, P=0.0001), epinephrine (46 (33) vs. 14 (6) ng/L, P=0.001), AVP (41 ± (18) vs. 12 (7) ng/L, P=0.0004), and active renin (27 (12) vs. 12 (4) ng/L, P = 0.001) were significantly higher in placebo-treated patients. Conclusion : Under combined general and epidural anesthesia arterial hypotension following MT due to endogenous PGI₂ release is associated with enhanced release of AVP, active renin, epinephrine and thromboxane A₂, presumably contributing to hemodynamic stability within 30 min after MT.     

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.     

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.     

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.     

Reduction of Plasma Fibrinogen, Immunoglobulin G, and Immunoglobulin M Concentrations by Immunoadsorption Therapy with Tryptophan and Phenylalanine Adsorbents

Abstract Immunoadsorption (1A) therapy with tryptophan (TR-350) or phenylalanine (PH-350) adsorbents has been used to reduce the concentration of serum antibodies in human lymphocyte antigen (HLA)-immunized patients. Other forms of plasma purification have been reported to reduce the level of fibrinogen, which affects the blood properties. In this study we investigated the effects of IA therapy using both adsorbents on plasma fibrinogen and immunoglobulins G and M in 13 patients (8 patients were treated with TR-350, and 5 patients were treated with PH-350). During each session 1 plasma volume (2.8 ± 0.4 L of plasma) was processed through the immunocolumn and then returned to the patient together with the blood cells. Compared with the pretreatment values, the plasma fibrinogen, IgG, and IgM concentrations were significantly reduced after IA therapy (p < 0.01 for TR-350; p < 0.04 for PH-350). There was a positive correlation between the degree of reduction of plasma proteins and the number of IA treatments given. A nonpara-metric test (Wilcoxon's signed-rank test or the Mann-Whitney test) was used for statistical analysis. We conclude from our study that IA therapy effectively lowers the plasma levels of fibrinogen, IgG, and IgM and thus can be considered a valuable alternative to other blood purification methods.     

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.     

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.