PI3K/Akt信号转导通路在二氮嗪预处理减轻大鼠海马神经元缺氧复氧损伤中的作用

目的 探讨PDK/Akt信号转导通路在二氮嗪预处理减轻大鼠海马缺氧复氧损伤中的作用.方法 新生SD大鼠,出生时间<24 h,体重5-6 g,断头取海马组织,胰蛋白酶消化后,将神经元接种于96孔板或直径35 mm培养皿中,培养12 d后,随机分为6组:对照组(C组)、缺氧复氧组(HR组)、二氮嗪100μmol/L预处理组(Dz组)、二氮嗪100 μmol/L预处理+5-羟癸酸100μmol/L预处理组(DZ+HD组)、5-羟癸酸100 μmol/L预处理组(HD组)和二氮嗪100 μmol/L预处理+LY294002 50μmol/L预处理组(Dz+LY组),每组48孔或12皿.C组不给予任何处理,其余5组每天给予相应药物预处理l h,连续3 d,然后缺氧4 h,复氧24 h,测定神经元活力、凋亡率、Akt、Bcl-2和Bax的表达水平.结果 与C组比较,其余各组海马神经元活力降低.凋亡率升高,Akt和Bcl-2和Bax表达上调(P<0.01);与HR组比较.DZ组海马神经元活力升高.凋亡率降低,Altt和Bel-2表达上调,Bax表达下调(P<0.01);与Dz组比较,DZ+HD组、HD组和Dz+LY组海马神经元活力降低,凋亡率升高.Akt和Bel-2表达下调,Bax表达上调(P<0.01).结论 二氮嗪预处理可能通过激活PDK/Akt信号转导通路,上调Bel-2表达,下调Bax表达,抑制神经元凋亡,从而减轻大鼠海马缺氧复氧损伤.     

二氮嗪预处理联合低温对大鼠海马神经元缺氧复氧时Bcl-2和Bax表达的影响

目的 二氮嗪预处理联合低温对大鼠海马神经元缺氧复氧时Bcl-2和Bax表达的影响.方法 清洁级SD大鼠,出生<24 h,体重5～6 g,离体培养海马神经元,接种于培养皿或96孔板.海马神经元随机分为8组,每组36孔或12皿:常温组(NT组)、二氮嗪预处理+常温组(DP+NT组)、浅低温组(MiH组)、二氮嗪预处理+浅低温组(DP+MiH组)、中低温组(MoH组)、二氮嗪预处理+中低温组(DP+MoH组)、深低温组(DeH组)和二氮嗪预处理+深低温组(DP+DeH组).DP+NT组、DP+MiH组、DP+MoH组和DP+DeH组培养液中加入二氮嗪,终浓度为100μmol/L,孵育1 h,1次/d,连续2 d,随后分别在37、34、30和22℃下缺氧4 h,37℃复氧48 hoNT组、MiH组、MoH组和DeH组分别在37、34、30和22℃下行缺氧4 h,37℃复氧48 h.于复氧48 h时测定海马神经元活力、凋亡率和Bcl-2和Bax 的表达水平,计算Bcl-2/Bax.结果 与NT组比较.DP+NT组、MiH组、MoH组和DeH组海马神经元活力升高,凋亡率降低,Bcl-2表达上调,Bax表达下调,Bcl/21Bax升高(P<0.05);与DP+NT组比较,DP+MiH组、DP+MoH组和DP+DeH组海马神经元活力升高,早期凋亡率降低,Bcl-2表达上调,Bax 表达下调,Bcl-21Bax升高(P<0.05),晚期凋亡率差异无统计学意义(P>0.05);与MiH组比较,DP+MiH组和DeH组海马神经元活力升高,早期凋亡率降低,Bcl-2表达上调,Bax表达下调,Bel-2/Bax升高(P<0.05),晚期凋亡率差异无统计学意义(P>0.05),MoH组上述指标差异无统计学意义(P>0.05);与DP+MiH组比较,DP+DeH组海马神经元活力升高,早期凋亡率降低,Bcl-2表达上调,Bax表达下调,Bcl-2/Bax升高(P<0.05).结论 二氮嗪预处理联合低温减轻大鼠神经元缺氧复氧损伤的机制可能与纠正Bcl-2与Bax失衡,抑制神经元早期凋亡有关.     

二氮嗪预先给药对原代培养大鼠海马神经元缺氧/复氧损伤的保护机制

目的研究ATP敏感性钾通道开放剂二氮嗪预先给药对新生Wistar大鼠原代培养海马神经元缺氧/复氧损伤的保护机制。方法原代培养的新生大鼠海马神经元随机分为2组,二氮嗪组(Dia组),缺氧前给予50μmol/L二氮嗪;对照组(Con组),给予二氮嗪的赋形剂,即含2‰二甲基亚砜的0.01 mol/L磷酸盐缓冲液;分别在缺氧3 h/复氧24 h和缺氧3 h/复氧48 h后,测定神经元存活能力及LDH漏出率;在缺氧3 h/复氧24 h后,测定丙二醛(MDA)和超氧化物歧化酶(SOD)水平;在缺氧3 h、缺氧3 h/复氧24 h和缺氧3 h/复氧48 h时,测定早期神经元凋亡率和死亡率。结果与Con组比较,Dia 组缺氧3 h复氧24 h时神经元存活能力升高,缺氧3 h/复氧48 h时LDH漏出率降低,缺氧3 h/复氧24 h培养液中MDA浓度降低,SOD活性升高(P<0.05或0.01);缺氧复氧各时点Dia组神经元坏死率降低,神经元凋亡率升高(P<0.05或0.01)。结论50 μmol/L二氮嗪预先给药减轻原代培养新生Wistar 大鼠海马神经元缺氧/复氧损伤的机制与增加SOD活性有关。     

心肌肽素预先给药对大鼠海马神经元缺氧复氧损伤的影响

目的 研究心肌肽素(CMP)预先给药对原代培养大鼠海马神经元缺氧复氧损伤的影响 及相关机制。方法原代培养SD大鼠海马神经元,随机分为4组:对照组、缺氧复氧组、CMP 10 μg／ml 组、CMP 100 μg／ml组。对照组不实行任何处理,缺氧复氧组海马神经缺氧4 h复氧48 h,建立神经元缺 氧复氧损伤模型。CMP 10 μg／ml、CMP 100 μg／ml组缺氧前30 min于培养液中加入相应浓度的CMP,缺 氧复氧组加入相应的溶剂。采用四唑蓝比色法测定神经元的细胞活力,采用细胞免疫化学法测定神 经元Bcl-2蛋白表达水平。结果与对照组比较。缺氧复氧组、CMP10 μg／ml组、CMP100μg／ml组海马 神经元缺氧复氧后细胞活力降低,Bcl-2蛋白表达升高(P<0．05),CMP 100 μg／ml组细胞活力及Bcl-2 蛋白表达高于缺氧复氧组和CMP10μg／ml组(P<0．05),CMP 10μg/ml组与缺氧复氧组之间上述两指 标比较差异无统计学意义(P>0．05)。结论CMP100μg／ml可增强Bcl-2蛋白的表达,减轻缺氧复氧 后海马神经元损伤。     

二氮嗪预处理对大鼠海马神经细胞缺氧复氧时c-Jun氨基末端激酶表达的影响

目的 评价二氮嗪预处理对大鼠海马神经细胞缺氧复氧时c-Jun氨基末端激酶(JNK)表达的影响.方法 SD大鼠100只,出生<24 h,体重5～6 g,断头取海马组织,制备海马神经细胞悬液,海马神经细胞接种于96孔板或直径35 mm培养皿中,培养9～10 d后,随机分为4组,每组36孔或8皿:对照组(C组)、缺氧复氧组(A/R组)、二氮嗪30 μmol/L组(D1组)和二氮嗪100 μmol/L组(D2组).C组不行任何处理;A/R组置于特制的无菌密闭容器,容器中通人95%N2-5%CO2混合气体,流速0.2 L/min,4 h后放回原培养箱继续培养24 h;D1组和D2组在培养液中加入二氮嗪,终浓度分别为30、100 μmol/L,孵育1 h后用全量培养液洗脱,1次/d,连续3 d,随后处理同A/R组.于培养24 h时行免疫组化染色,观察神经细胞病理学结果 ,四甲基偶氮唑蓝比色法测定海马神经细胞活力,Westernblot法测定海马神经细胞Bcl-2、Bax和JNK的表达.结果 与C组比较,其余3组海马神经细胞Bcl-2、Bax和JNK表达均上调,活力降低(P<0.05或0.01);与A/R组比较,D2组海马神经细胞Bcl-2表达上调,Bax和JNK表达下调,活力升高(P<0.05或0.01),D1组上述指标差异无统计学意义(P>0.05).结论 二氮嗪预处理可能通过下调JNK的表达,抑制JNK信号通路,维持Bcl-2与Bax的平衡,减轻大鼠海马神经细胞缺氧复氧损伤.     

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.     

氯胺酮预先给药对缺氧复氧诱导大鼠小脑颗粒神经元凋亡的影响

目的 研究氯胺酮预先给药对缺氧复氧诱导大鼠小脑颗粒神经元（CGNs）凋亡的影响，及磷脂酰肌醇-3-激酶（PI3K）／Akt通路在其中的作用。方法 出生7-8d的清洁级SD大鼠，雌雄不拘，体重15～20g；制备CGNs，培养的8d的CGNs随机分为5组，对照组（A组）、缺氧复氧组（B组）、氯胺酮预先给药组（C组）、PDK／Akt通路的特异性抑制剂Ly294002-氯胺酮预先给药组（D组）、Ly294002组（E组）。B组将CGNs放入特制缺氧盒中，缺氧3h后复氧；C组缺氧前1h加入200μmol／L氯胺酮；D组加入氯胺酮前30min加入20μmol／LLy294002；E组加入20μmol／LLy294002。复氧16h后进行下述指标的观察。二乙酸荧光素染色法测定CGNs存活率，Hoechst33258核染色检测CGNs凋亡细胞核，琼脂糖凝胶电泳检测DNA片断化水平，蛋白免疫印迹法（Western blot法）检测CGNs磷酸化Akt、磷酸化GSK3β及总Akt水平。结果缺氧复氧可诱导CGNs的凋亡，降低CGNs磷酸化Akt和磷酸化GSK3β水平（P〈0．05），氯胺酮预先给药可减轻缺氧复氧诱导的上述改变，氯胺酮对CGNs的这种保护作用可被Ly294002部分抑制。结论 氯胺酮预先给药可减轻缺氧复氧诱导大鼠CGNs凋亡，其机制与激活PI3K／Akt通路有关。     

二氮嗪预先给药对大鼠心肌微血管内皮细胞缺氧复氧时NF-κB mRNA和fractalkine mRNA表达的影响

目的 探讨二氮嗪预先给药对大鼠心肌微血管内皮细胞缺氧复氧时NF-κB mRNA和fractalkine(FKN)mRNA表达的影响.方法 培养SD大鼠心肌微血管内皮细胞,以1×106个/ml的密度接种于96孔板(100μl/孔)或培养皿(2 ml/皿),随机分为4组(n=24).正常对照组(C组)不作任何处理,缺氧复氧组(H/R组)、二氮嗪预先给药组(DZ组)、二氮嗪预先给药+线粒体ATP敏感性钾通道阻断剂5-羟葵酸组(DZ+5-HD组)均进行缺氧2 h、复氧2 h.DZ组和DZ+5-HD组在缺氧前2 h分别加入100 μmol/L二氮嗪、100 μmol/L二氮嗪+100μmol/L 5-羟葵酸.于复氧2 h时测定细胞活力、细胞凋亡率、NF-κB mRNA和FKN mRNA表达水平.结果 与C组比较,H/R组细胞活力降低,细胞凋亡率升高,NF-κB mRNA和FKN mRNA表达上调(P＜0.01);与H/R组比较,DZ组细胞活力升高,细胞凋亡率降低,NF-κB mRNA和FKN mRNA表达下调(P＜0.05);5-羟葵酸可抑制二氮嗪预先给药导致的上述改变(P＜0.05).结论 二氮嗪预先给药可下调NF-κB和FKN表达,从而减轻大鼠心肌微血管内皮细胞缺氧复氧损伤,其机制与激活线粒体ATP敏感性钾通道有关.     

硫化氢对大鼠海马神经元氧-糖缺失/恢复损伤的影响

目的研究硫化氢（H2S）对大鼠海马神经元氧-糖缺失/恢复损伤的影响。方法新生（24～48h内）Wistar大鼠断头,迅速取出海马,应用0．125%胰酶消化,海马神经元在96孔和6孔培养板上培养10d后随机分为5组：正常培养组（Ⅰ组）、氧-糖缺失/恢复组（Ⅱ组）、氧-糖缺失/恢复＋50μmol/L NaHS组（Ⅲ组）、氧-糖缺失/恢复＋100μmol/L NaHS组（Ⅳ组）和氧-糖缺失/恢复＋200μmol/L NaHS组（Ⅴ组）。Ⅱ组神经元进行氧-糖缺失45min后换回原来的培养液,然后放回原培养箱培养24 h,Ⅲ组、Ⅳ组和Ⅴ组在氧-糖缺失时加入NaHS,使其终浓度分别为50、100、200μmol/L,余处理同Ⅱ组,Ⅰ组按正常培养方法培养。检测96孔培养板神经元活力。鉴定6孔培养板的神经元纯度并进行细胞色素C水平、还原型谷胱甘肽（GSH）、丙二醛（MDA）浓度和神经元凋亡的检测。结果与Ⅰ组比较,Ⅱ组MDA浓度、细胞色素C水平和神经元凋亡率升高,GSH浓度和神经元活力降低（P＜0．05）；与Ⅱ组比较,Ⅲ组、Ⅳ组和Ⅴ组MDA浓度、细胞色素C水平和神经元凋亡率降低,GSH浓度和神经元活力升高（P＜0．05）；与Ⅲ组比较,Ⅳ组和Ⅴ组MDA浓度、细胞色素C水平和神经元凋亡率降低,GSH浓度和神经元活力升高（P＜0．05）；与Ⅳ组比较,Ⅴ组MDA浓度、细胞色素C水平和神经元凋亡率降低,GSH浓度和神经元活力升高（P＜0．05）。结论外源性H2S可减轻大鼠海马神经元氧-糖缺失/恢复损伤,其机制可能与其提高机体的抗氧化能力、减少神经元的凋亡有关。     

二氮嗪预先给药对大鼠心肌微血管内皮细胞缺氧复氧时PI3K mRNA和Akt mRNA表达的影响

目的 评价二氮嗪预先给药对大鼠心肌微血管内皮细胞缺氧复氧时磷脂酰肌醇-3激酶(PI3K) mRNA和蛋白质丝氨酸苏氨酸激酶(Akt) mRNA表达的影响.方法 培养SD大鼠心肌微血管内皮细胞,以1×106个/ml密度接种于96孔培养板(100μl/孔)或培养皿(2 ml/皿),采用随机数字表法,将其随机分为4组(n=25).正常对照组(C组)不作任何处理;缺氧复氧组(H/R组)、二氮嗪预先给药组(DZ组)、二氮嗪预先给药+线粒体ATP敏感性钾通道阻断剂5-羟葵酸组(DZ+ 5-HD组)均进行缺氧2h,复氧2h.DZ组和DZ+ 5-HD组在缺氧前2h分别加入100 μmol/L二氮嗪、100μnol/L二氮嗪+ 100 μmol/L 5-羟葵酸.于复氧2h时测定细胞活力、细胞凋亡率、PI3K mRNA和Akt mRNA表达.结果 与C组比较,H/R组细胞活力降低,细胞凋亡率升高,PI3K mRNA和Akt mRNA表达上调(P＜0.05或0.01);与H/R组比较,DZ组细胞活力升高,细胞凋亡率降低,PI3K mRNA和Akt mRNA表达上调(P ＜0.05或0.01);5-羟葵酸可逆转二氮嗪预先给药导致的上述改变(P＜0.05或0.01).结论 二氮嗪预先给药减轻大鼠心肌微血管内皮细胞缺氧复氧损伤的机制与激活线粒体ATP敏感性钾通道,促进PI3K和Akt基因的转录有关.     

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.     

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.