瞬时受体电位阳离子通道M7在海马神经元损伤中的作用

目的探讨瞬时受体电位阳离子通道M7(TRPM7)在七氟醚预处理缓解缺血缺氧性损伤(OGD)后海马神经元损伤中的作用。方法出生1d的SD大鼠,提取海马神经元,将其随机分为五组:对照组(C组)、七氟醚预处理组(Sev组)、OGD组、七氟醚预处理+OGD组(SD组)和七氟醚预处理+缓激肽(TRPM7特异性激动剂)+OGD(B组)。缺糖缺氧1.5h后复糖复氧,再正常培养24h以制备OGD模型。C组海马神经元仅做正常培养;Sev组海马神经元行2%七氟醚预处理1h;OGD组海马神经元仅制备OGD模型;SD组海马神经元行2%七氟醚预处理1h,24h后制备OGD模型;B组神经元于七氟醚预处理前15 min在培养基中加入缓激肽(TRPM7特异性激动剂,终浓度200μmol/L),之后行2%七氟醚预处理1h,24h后制备OGD模型。正常培养24h后,分别采用MTT法检测神经元相对存活指数,TUNEL凋亡染色法检测神经元凋亡率,Western blot检测TRPM7蛋白含量,实时定量PCR法检测TRPM7 mRNA表达水平,ELISA法测定神经元IL-1β和TNF-α蛋白含量。结果 OGD组海马神经元TRPM7蛋白含量及mRNA表达水平、凋亡率、IL-1β、TNF-αmRNA表达水平及上清蛋白含量明显高于C组(P0.05),而相对存活指数明显降低于C组(P0.05)。SD组海马神经元TRPM7蛋白含量及mRNA表达水平、凋亡率、IL-1β、TNF-αmRNA表达水平及上清蛋白含量明显低于OGD组(P0.05),而相对存活指数明显高于OGD组(P0.05)。B组海马神经元TRPM7蛋白含量及mRNA表达水平、凋亡率、IL-1β、TNF-αmRNA表达水平及上清蛋白含量明显高于SD组(P0.05),而相对存活指数明显低于SD组(P0.05)。结论七氟醚预处理可通过缓解神经元TRPM7过度表达,减轻缺血缺氧性损伤后海马神经元凋亡和炎症反应。     

细胞自噬在七氟醚致老年小鼠海马区神经元细胞凋亡中的保护作用

目的探讨细胞自噬在七氟醚致老年小鼠海马区神经元细胞凋亡中的作用机制。方法 18月龄BL/C57小鼠16只, 按随机数字表法分为两组(每组8只):七氟醚组和对照组。七氟醚组吸入47.5%空气+2.5%七氟醚+50%氧气3 h, 对照组吸入50%空气+50%氧气3 h。建模后24 h进行新物体识别实验, 随后断头取海马组织, 尼氏染色检测海马神经元细胞凋亡情况, Western blot法检测海马神经元细胞自噬相关蛋白[微管关联蛋白(microtubule-associated protein, LC)3Ⅱ/LC3Ⅰ、Becline-1、p62蛋白]水平。另取18月龄BL/C57小鼠18只, 按随机数字表法分为3组(每组6只):七氟醚+3-甲基腺嘌呤组(M组, 吸入麻醉前2 h经腹腔注射3-甲基腺嘌呤)、七氟醚+雷帕霉素组(R组, 吸入麻醉前24 h和2 h经腹腔注射雷帕霉素)、七氟醚+生理盐水组(N组, 吸入麻醉前2 h经腹腔注射生理盐水100 μl)。经腹腔注药及七氟醚处理后, 尼氏染色检测海马神经元细胞凋亡情况, Western blot法检测海马神经元细胞自噬相关蛋白(LC3Ⅱ/L...     

促红细胞生成素在七氟醚麻醉诱发老龄大鼠海马神经细胞凋亡中的作用

目的探讨促红细胞生成素(erythropoietin,EPO)减轻七氟醚麻醉诱发老龄大鼠海马神经细胞凋亡的作用以及与Toll样受体4(toll like receptor 4,TLR4)的关系。方法雄性SD大鼠,20月龄,体重550~750g,根据随机数字表法将大鼠分为三组(n=9):对照组(C组),七氟醚处理组(S组)和EPO+七氟醚处理组(ES组)。S及ES组大鼠吸入4%七氟醚6h;C组仅吸入空气-氧气混合气体;ES组大鼠在七氟醚处理后24、48和72h行尾缘静脉注射EPO(5 000U/kg),C组和S组仅注射等量生理盐水。采用Morris水迷宫实验评价大鼠的认知能力,采用TUNEL法评价大鼠海马神经细胞凋亡率,采用RT-PCR法测定海马组织中TLR4mRNA表达,采用JC-1免疫荧光染色法检测海马神经细胞线粒体膜电位水平;采用免疫蛋白印迹法测定海马组织中淀粉样前体蛋白(APP)和β-淀粉样肽(Aβ)蛋白表达。结果与C组比较,S组逃避潜伏期明显延长,穿越平台次数差异无统计学意义,神经细胞凋亡率明显增加,TLR4mRNA表达明显下降,海马神经细胞线粒体膜电位水平明显下降,APP和Aβ表达明显增加(P0.05);与S组比较,ES组逃避潜伏期明显缩短,穿越平台次数差异无统计学意义,神经细胞凋亡率明显下降,TLR4 mRNA表达明显升高,海马神经细胞线粒体膜电位水平上升,APP和Aβ表达明显减少(P0.05)。结论促红细胞生成素能够减轻七氟醚诱发老龄大鼠海马区神经细胞的凋亡,其机制可能与抑制TLR4 mRNA表达,改善线粒体膜电位水平和抑制APP和Aβ蛋白活化相关。     

抗氧化剂MitoQ对异氟醚诱导大鼠海马神经元损伤的影响及机制

目的探讨抗氧化剂MitoQ对异氟醚诱导的新生大鼠海马神经元细胞损伤的影响及潜在机制。方法 SPF级健康SD大鼠15只,7日龄,体重15~20g。采用随机数字表法分为三组:对照组(C组)、异氟醚组(I组)和异氟醚+MitoQ组(IM组),每组5只。C组吸入空-氧混合气体。Ⅰ组于出生后7、14和21d吸入1.5%异氟醚2h,IM组在每次吸入异氟醚前腹腔注射MitoQ0.4ml/kg。于出生后28d采用HE染色观察各组大鼠海马CA1区海马神经元细胞形态。分离培养新生大鼠原代海马神经元细胞培养并分组处理,采用MTT法和TUNEL原位荧光染色法检测细胞存活率和凋亡率;采用硫代巴比妥酸法和黄嘌呤氧化酶法检测细胞中丙二醛(MDA)浓度和超氧化物歧化酶(SOD)活性;采用Rhodamine 123染色荧光显微镜照相法检测线粒体膜电位(MMP),DCFH-DA染色荧光显微镜照相法检测细胞内活性氧簇(ROS)生成量,采用Western blot法检测海马神经元细胞中Bax、Bcl-2和caspase-3蛋白含量。结果与C组比较,Ⅰ组大鼠海马组织神经细胞受损明显,细胞数目减少,Ⅰ组细胞存活率明显降低,细胞凋亡率明显升高,MDA浓度明显升高,SOD活性明显降低,ROS生成量明显增加,MMP水平明显降低,Bax和caspase-3蛋白含量明显升高,Bcl-2蛋白含量明显降低(P0.05);与Ⅰ组比较,IM组大鼠海马组织神经细胞损伤减少,细胞存活率明显升高,细胞凋亡率明显降低,MDA浓度明显降低,SOD活性明显升高,ROS生成量明显减少,MMP水平明显升高,Bax和caspase-3蛋白含量明显降低,Bcl-2蛋白含量明显升高(P0.05)。结论抗氧化剂MitoQ可明显抑制异氟醚诱导的海马神经元细胞损伤,这与其拮抗细胞氧化应激和维持线粒体功能作用密切相关。     

不同浓度七氟醚预处理对大鼠海马神经元缺氧复氧时细胞凋亡的影响及线粒体ATP敏感型钾通道在其中的作用

目的 探讨不同浓度七氟醚预处理对大鼠海马神经元缺氧复氧时细胞凋亡的影响及线粒体ATP敏感型钾通道(mito-KATP通道)在其中的作用.方法 新生(出生＜24 h)SD大鼠,雌雄不拘,体重5～6 g,原代培养海马神经元,接种于培养孔或培养皿中,采用随机数字表法,将其随机分为7组,每组48孔和12皿,正常对照组(C组):不予任何处理;缺氧复氧组(HR组):缺氧4 h复氧24 h;6%七氟醚预处理组(S1 组)、4%七氟醚预处理组(S2 组)、2%七氟醚预处理组(S3 组):分别经6%、4%、2%七氟醚预处理后行缺氧复氧;5-羟葵酸100 μmol/L预处理组(5-HD组):经mito-KATP通道阻断剂5-羟葵酸(终浓度100 μmol/L)预处理后进行缺氧复氧;5-羟葵酸100 μmol/L+6%七氟醚预处理组(5-HD+S组):同时行5-羟葵酸和6%七氟醚预处理后进行缺氧复氧.各组以上处理结束后,测定神经元活力、凋亡率、Bcl-2和Bax蛋白的表达水平.结果 与C组比较,其余6组海马神经元活力降低,细胞凋亡率升高,Bcl-2和Bax蛋白表达上调(P＜0.01);与HR组比较,S1组～S3组海马神经元活力增强,细胞凋亡率降低,Bcl-2蛋白表达上调,Bax蛋白表达下调(P＜0.01),5-HD组和5-HD+S组上述指标比较差异无统计学意义(P＞0.05);与S1组比较,S2组、S3组和5-HD+S组海马神经元活力降低,细胞凋亡率升高,Bcl-2蛋白表达下调,Bax蛋白表达上调(P＜0.01);与S2组比较,S3组海马神经元活力降低,细胞凋亡率升高,Bcl-2蛋白表达下调,Bax蛋白表达上调(P＜0.01).结论 七氟醚预处理可抑制大鼠海马神经元缺氧复氧时细胞凋亡,从而减轻神经元损伤,且呈浓度依赖性,机制可能与开放神经元mito-KATP通道,上调Bcl-2蛋白表达,下调Bax蛋白表达有关.

Abstract：

Objective To investigate the effect of preconditioning with different concentrations of sevoflurane on hypoxia-reoxygenation(H/R)-induced apoptosis in rat hippocampal neurons and the role of mitochondrial KATP(mito-KATP)channels.Methods Primary cultured hippocampal neurons isolated from newborn SD rats(＜24h)of both sexes,weighing 5-6 g,were randomly divided into 7 groups with 48 wells and 12 dishes in each one:control group(C group),H/R group,preconditioning with 6%,4%and 2% sevoflurane groups(S1-3 groups),5-hydroxydecanoate(5-HD,mito-KATP channel blocker)100 μmol/L preconditioning group(5-HD group)and preconditioning with 5-HD 100 μmol/L+6% sevoflurane group(5-HD+S group).The neurons were exposed to 4 h hypoxia followed by 24 h reoxygenation. In S1-3 groups, preconditioning was performed with 6% , 4% and 2% sevoflurane respectively before H/R. In 5-HD group, preconditioning was performed with 5-HD (final concentration 100 μmol/L) before H/R. In 5-HD + S group, preconditioning was performed with 5-HD 100 μmol/L and 6% sevoflurane before H/R. The neuronal viability, apoptosis rate and expression of Bcl-2 and Bax were determined after 24 h reoxygenation.Results The neuronal viability was significantly lower,while the apoptosis rate and expression of Bcl-2 and Bax were significantly higher in the other 6 groups than in group C(P＜0.01).The neuronal viability and expression of Bcl-2 were significantly higher,while the apoptosis rate and Bax expression were lower in S1-3 groups than in group H/R. There was no significant difference in the parameters mentioned above between 5-HD and 5-HD + S groups(P＞0.05).The neuronal viability and expression of Bcl-2 were significantly lower, while the apoptosis rate and Bax expression were higher in S2, S3 and 5-HD + S groups than in group S1, and in group S3 than in group S2(P＜0.0l) .Conclusion Sevoflurane preconditioning can inhibit H/R-induced apoptosis in rat hippocampal neurons and reduce the injury to neurons in a concentration-dependent manner, and the underlying mechanism may be related to activation of mito-KATP channels, up-regulation of Bcl-2 expression and down-regulation of Bax expression.     

不同浓度七氟醚对大鼠原代皮质神经元的影响

目的评价不同浓度七氟醚对大鼠原代皮质神经元的毒性作用。方法出生24h内的SD大鼠48只,体外培养大鼠皮质神经元并接种于6孔板(2cm)或12孔板(4.5 mm)培养皿,采用随机数字表法分为四组:1%七氟醚处理组(A组)、2%七氟醚处理组(B组)、4%七氟醚处理组(C组)和对照组(D组),每组12只。A、B、C组神经元分别给予1%、2%和4%浓度的七氟醚处理6h,D组神经元正常培养,采用CCK-8法测定细胞存活率,采用乳酸脱氢酶(LDH)法测定细胞死亡率,采用免疫蛋白印迹(Western blot)法测定凋亡蛋白caspase-3 17kDa片段评价细胞凋亡和促凋亡蛋白Bid、Bim和Puma的表达。结果 B、C组神经元的存活率明显低于D组,死亡率明显高于D组,caspase-3的17kDa片段、Bid、Bim和Puma表达明显高于D组(P0.05);C组神经元的存活率明显低于B组,死亡率明显高于B组,caspase-3的17kDa片段、Bid、Bim和Puma表达明显高于B组(P0.05)。A、D组各指标差异均无统计学意义。结论随着吸入七氟醚浓度的升高,七氟醚可能通过促进促凋亡蛋白Bid、Bim和Puma的表达增加对神经元的毒性作用。     

七氟醚单次和多次暴露对新生鼠海马神经元结构的影响

目的探讨等同时间不同次数七氟醚暴露对新生大鼠海马CA1细胞形态及超微结构的影响。方法出生7d的SD雄性大鼠45只,体重14~18g,随机均分为三组:对照组(C组)、单次七氟醚暴露组(SS组)和多次七氟醚暴露组(TS组)。SS组于出生后第7天吸入1次3%七氟醚6h;TS组于出生后第7、8、9天每天吸入1次3%七氟醚2h,累计6h;C组在相应日龄吸入60%氧气。三组于出生后第14天灌注取脑,采用HE和尼氏染色观察大鼠海马CA1区锥体神经元形态及数量变化;同时,透射电镜下观察该区域神经元超微结构及突触后致密物厚度和活性区长度。结果 HE和尼氏染色显示:与C组比较,SS组和TS组海马CA1细胞排列稀疏,神经元数量明显减少(P0.05);与SS组比较,TS组海马CA1神经元数量明显减少(P0.05)。电镜结果显示:与C组比较,SS组和TS组海马CA1神经元亚细胞器均有不同程度的受损,突触后致密物厚度明显变薄,活性区长度明显缩短(P0.05);与SS组比较,TS组神经元亚细胞器损伤更明显,突触后致密物厚度更薄,活性区长度缩短更严重(P0.05)。结论七氟醚单次和多次暴露均会引起新生大鼠海马CA1区锥体神经元数量减少及细胞超微结构的改变,等同时间多次暴露比单次暴露对神经元形态的损伤更严重。     

异氟醚通过上调NMDA受体导致发育期大鼠海马神经元凋亡

目的探讨异氟醚麻醉对新生大鼠海马神经元N-甲基-D-天冬氨酸(NMDA)受体亚基及凋亡的影响。方法新生1d的SD大鼠36只,雌雄不拘,取海马组织进行原代培养。采用随机数字表法将培养海马神经元5d的培养皿随机分为三组:对照组(C组)、异氟醚组(I组)和AP5+异氟醚组(A组),每组12只。I组和A组培养的海马神经元放置在密闭箱中,吸入1.5%异氟醚和纯氧,吸入时间6h,C组不做任何处理。于异氟醚麻醉结束后2、4、6、24h(C组于相应时点),提取海马神经元总mRNA和总蛋白,采用RT-PCR法测定NR2A mRNA、NR2BmRNA和caspase-3mRNA的表达量,采用Westen blot法测定caspase-3蛋白含量。结果与C组比较,异氟醚麻醉结束后2、4和6hI组海马神经元NR2AmRNA和NR2BmRNA的表达量明显上调(P0.05)。与C组和A组比较,I组异氟醚麻醉结束后2、4和6h海马神经元caspase-3mRNA的表达量、异氟醚麻醉后4和6h海马caspase-3蛋白含量明显升高(P0.05)。结论吸入1.5%异氟醚可能通过上调新生大鼠海马神经元NMDA受体导致发育神经元凋亡,阻断NMDA受体可以预防异氟醚导致的发育期海马神经元凋亡。     

七氟醚后处理对大鼠脑缺血-再灌注损伤海马血红素氧合酶-1蛋白表达的影响

目的 探讨七氟醚后处理对大鼠脑缺血-再灌注损伤的保护作用及血红素氧合酶-1(HO-1)在其中的作用.方法 清洁级雄性SD大鼠40只,体重230～270 g,随机均分为五组:假手术组(C组),缺血-再灌注组(IR组),七氟醚组(S组),七氟醚+锌原卟啉Ⅸ(Znpp)组(SZ组)和溶剂对照组(SD组).采用双侧颈总动脉夹闭合并取血降压再回输的方法制备脑缺血-再灌注损伤模型,S组再灌注前5 min气管插管,吸入1MAC七氟醚15 min; SZ组模型制备前腹腔注射Znpp45μmol/kg,溶于二甲基亚砜(DMSO)0.5 ml; SD组模型制备前腹腔注射DMSO 0.5 ml.所有大鼠再灌注24 h后处死,取海马.光镜下观察各组海马病理学变化,检测海马超氧化物歧化酶(SOD)活性、丙二醛(MDA)含量和HO-1蛋白表达.结果 与C组比较,其余四组SOD活性明显降低(P＜0.05),MDA含量明显升高(P＜0.05),SZ组HO-1蛋白表达差异无统计学意义,IR、S和SD组HO-1蛋白表达明显升高(P＜0.05).与IR组比较,S组和SD组SOD活性和HO-1蛋白表达明显升高(P＜0.05),MDA含量明显降低(P＜0.05),SZ组HO-1蛋白表达明显降低(P＜0.05).光镜下S组和SD组海马病理学损伤较IR组和SZ组减轻.结论 七氟醚后处理对大鼠脑缺血-再灌注损伤有保护作用,其作用机制可能与七氟醚上调脑组织中HO-1蛋白表达有关.     

长链非编码RNAβ分泌酶1反义转录物在七氟醚诱发老年大鼠认知功能下降中的作用

目的探讨长链非编码RNA(lncRNA)β分泌酶1反义转录物(BACE1-AS)在七氟醚诱发老年大鼠认知功能下降中的作用。方法 SPF级健康雄性SD老年大鼠64只,18月龄,体重480～580 g。采用随机数字表法分为四组:对照组(C组)、七氟醚组(S组)、七氟醚+阴性对照质粒组(SN组)和七氟醚+BACE1-AS抑制剂(siRNA-BACE1-AS)组(ST组),每组16只。SN组和ST组分别侧脑室注射阴性对照质粒和siRNA-BACE1-AS,C组和S组注射等体积PBS溶液,注射后1 d C组吸入30%氧气6 h, S组、SN组和ST组吸入3.6%七氟醚与30%氧气的混合气体6 h。气体吸入后1 d,采用水迷宫实验测实验第1～5天逃避潜伏期和实验第6天穿越平台次数。水迷宫实验结束后1 h内处死大鼠,取海马组织,采用ELISA法检测海马组织TNF-α、IL-1β、丙二醛(MDA)和超氧化物歧化酶(SOD)浓度,可见分光光度计法检测海马组织caspase-3活性,Western blot法检测海马组织Bax、Bcl-2和BACE1蛋白含量,RT-qPCR法检测海马组织lncRNA BACE1-AS、miR-124和BACE1 mRNA表达量,TUNEL法测定海马组织神经细胞凋亡百分比,苏木素伊红染色法观察海马组织病理结构。结果与C组比较,S组、SN组和ST组水迷宫实验第3～5天逃避潜伏期明显延长(P0.05),实验第6天穿越平台次数明显减少(P0.05),海马组织TNF-α、IL-1β和MDA浓度、BACE1和Bax蛋白含量、lncRNA BACE1-AS和BACE1 mRNA表达量、凋亡细胞百分比明显升高(P0.05),SOD浓度、Bcl-2蛋白含量、miR-124 mRNA表达量明显降低(P0.05),caspase-3活性明显增强(P0.05)。与S组比较,ST组水迷宫实验第3～5天逃避潜伏期明显缩短(P0.05),实验第6天穿越平台次数明显增多(P0.05),海马组织TNF-α、IL-1β和MDA浓度、BACE1和Bax蛋白含量、lncRNA BACE1-AS和BACE1 mRNA表达量、凋亡细胞百分比明显降低(P0.05),SOD浓度、Bcl-2蛋白含量、miR-124 mRNA表达量明显升高(P0.05),caspase-3活性明显减弱(P0.05)。S组和SN组上述指标差异均无统计学意义。结论长链非编码RNAβ分泌酶1反义转录物参与七氟醚诱导老年大鼠认知功能下降,其机制与神经细胞炎症、氧化应激损伤、调控miR-124和BACE1表达和促进细胞凋亡有关。     

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.     

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.     

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.