铁死亡抑制剂Ferrostatin-1在心肺转流大鼠认知功能中的作用

目的 探讨铁死亡抑制剂Ferrostatin-1在心肺转流（CPB）大鼠认知功能中的作用。

方法 选择SPF级健康雄性SD大鼠24只,12周龄,体重350～400 g。采用随机数字表法将大鼠分为三组：假手术组（S组）、CPB组（C组）和CPB＋Ferrostatin-1组（F组）,每组8只。S组行股动静脉及颈内静脉穿刺置管,不进行CPB;C组穿刺置管后行CPB 60 min;F组术前腹腔注射Ferrostatin-1 5 mg/kg,60 min后穿刺置管并行CPB 60 min。于术后第3天行水迷宫实验,记录潜伏期和穿越平台次数。处死大鼠,采用ELISA法检测海马组织活性氧（ROS）、丙二醛（MDA）、谷胱甘肽（GSH）浓度,亚铁嗪比色法检测海马组织Fe²⁺浓度,Western blot法检测海马组织τau蛋白、β-淀粉样蛋白（Aβ）和谷胱甘肽过氧化物酶4（GPX4）蛋白含量,HE染色观察海马组织锥体细胞病理变化,透射电镜观察海马组织锥体细胞线粒体结构。

结果 与S组比较,C组和F组潜伏期明显延长（P＜0.05）,穿越原平台次数明显减少（P＜0.05）,海马组织ROS、MDA、Fe²⁺浓度、τau蛋白和Aβ蛋白含量明显升高（P＜0.05）,GSH浓度和GPX4蛋白含量明显降低（P＜0.05）,海马组织锥体细胞核固缩,线粒体损伤加重。与C组比较,F组潜伏期明显缩短（P＜0.05）,穿越原平台次数明显增多（P＜0.05）,海马组织ROS、MDA、Fe²⁺浓度、τau蛋白和Aβ蛋白含量明显降低（P＜0.05）,GSH浓度和GPX4蛋白含量明显升高（P＜0.05）,海马组织锥体细胞病理结构和线粒体损伤减轻。

结论 CPB诱导大鼠海马组织神经元发生铁死亡,诱发大鼠术后认知功能障碍,Ferrostatin-1通过抑制铁死亡降低大鼠海马组织ROS、MDA、Fe²⁺浓度和τau、Aβ蛋白含量,改善CPB大鼠的术后认知功能。     

七氟醚对低温全心缺血-再灌注心脏电传导及Cx43 Ser368磷酸化的影响

目的 观察七氟醚对低温全心缺血-再灌注心室肌电传导及Cx43 Ser368磷酸化的影响。
方法 制备成功的离体灌注工作心脏24只,随机分为三组：对照组（C组）、低温全心缺血-再灌注组（IR组）和1.0 MAC七氟醚处理组（Sev组）,每组8只。C组：37 ℃ K-H液平衡灌注15 min后继续灌注37 ℃ K-H液105 min;IR组：37 ℃ K-H液平衡灌注15 min后继续灌注37 ℃ K-H液15 min,注射Thomas液（4 ℃,20 ml/kg）使心脏停搏60 min,4 ℃ K-H液保护心脏,停搏30 min时半量复灌Thomas液（4 ℃,10 ml/kg）,60 min时使用37 ℃ K-H液再灌注30 min;Sev组：37 ℃ K-H液平衡灌注15 min后继续灌注含饱和1.0 MAC七氟醚的37 ℃ K-H液15 min,注射Thomas液（4 ℃,20 ml/kg）使心脏停搏60 min,4 ℃ K-H液保护心脏,停搏30 min时半量复灌Thomas液（4 ℃,10 ml/kg）,60 min时使用含饱和1.0 MAC七氟醚的37 ℃ K-H液再灌注30 min。于再灌注即刻至灌注结束,记录离体心脏复跳时间（再灌注即刻至心脏首次跳动所需的时间）,室性心律失常（室性早搏、室性心动过速、室性颤动）发生情况和持续时间。采用心脏刺激仪行程控刺激,测定并记录有效不应期（ERP）、传导速度(CV）。采用免疫印迹法检测心室肌组织Cx43和Cx43 Ser368蛋白相对含量。
结果 与C组比较,IR组和Sev组ERP明显延长,CV明显减慢（P＜0.05）;IR组Cx43及Cx43 Ser368蛋白相对含量明显降低（P＜0.05）。与IR组比较,Sev组心脏复跳时间明显缩短,心律失常发生率明显降低,心律失常持续时间明显缩短,ERP明显缩短,CV明显增快,Cx43及Cx43 Ser368蛋白相对含量明显升高（P＜0.05）。
结论 七氟醚可以上调低温全心缺血-再灌注心室肌组织Cx43和Cx43 Ser368的表达,促使心室肌电传导增快、有效不应期缩短,降低再灌注心律失常的发生。     

地氟醚通过上调miR-29b表达减轻大鼠的心肌损伤

目的 探讨微小RNA-29b（miR-29b）在地氟醚处理减轻大鼠心肌梗死中的作用。
方法 成年雄性健康Wistar大鼠80只,10周龄,体重350～400 g,随机分为五组：假手术组（S组）、心肌梗死组（MI组）、地氟醚组（MD组）、空载AAV9组（MA组）和miR-29b沉默组（MR组）,每组16只。S组仅分离冠状动脉不结扎,其余组均建立心肌梗死模型,S组和MI组造模前3 d经尾静脉注射磷酸缓冲液（PBS）,MD组造模前3 d经尾静脉注射PBS,并于造模前30 min吸入5.9%地氟醚1 h,之后吸入1.3%地氟醚维持麻醉,MA组和MR组造模前3 d分别经尾静脉注射AAV9、AAV9-miR-29b-sponge,余同MD组。再灌注120 min后,采用Werstern blot法检测心肌组织转录激活因子3（STAT3）、p-STAT3、白介素-1β（IL-1β）、肿瘤坏死因子-α（TNF-α）蛋白含量;RT-qPCR检测心肌组织miR-29b表达量;红四氮唑（TTC）和HE染色观察心肌梗死面积百分比和组织形态;TargetScan预测并用双荧光素酶实验验证miR-29b与STAT3的靶向关系。
结果 与S组比较,MI组STAT3、p-STAT3、IL-1β、TNF-α蛋白相对含量明显升高,miR-29b相对表达量明显降低,心肌梗死面积百分比明显增大（P＜0.05）,心肌组织可见炎症浸润等损伤。与MI组比较,MD组STAT3、p-STAT3、IL-1β、TNF-α蛋白相对含量明显降低,miR-29b相对表达量明显升高,心肌梗死面积百分比明显减小（P＜0.05）,心肌组织损伤减轻。与MA组比较,MR组STAT3、p-STAT3、IL-1β、TNF-α蛋白相对含量明显升高,miR-29b相对表达量明显降低,心肌梗死面积百分比明显增大（P＜0.05）,心肌组织损伤加重。转染STAT3-3′UTR-WT、miR-29b mimics的心肌细胞荧光素酶活性明显弱于转染STAT3-3′UTR-WT、miR-29b NC的心肌细胞（P＜0.05）。
结论 地氟醚处理可通过上调miR-29b表达,靶向抑制STAT3表达,抑制STAT3相关炎症反应,减轻大鼠心肌梗死损伤,发挥心肌保护作用。     

远端缺血预处理对老年患者胃肠道恶性肿瘤根治术后早期心肌损伤的影响

目的 探讨远端缺血预处理（RIPC）对老年患者胃肠道恶性肿瘤根治术后早期心肌损伤的影响。
方法 选择行胃肠道恶性肿瘤根治术的老年患者59例，男43例，女16例，年龄65～85岁，BMI 18～35 kg/m²，ASA Ⅱ或Ⅲ级。将患者随机分为两组：远端缺血预处理组（RIPC组，n=27）和对照组（C组，n=32）。RIPC组于麻醉后、手术开始前进行3个循环的RIPC，每个循环行单侧下肢缺血5 min，再灌注5 min；C组不做处理。两组麻醉方案和手术操作均相同。记录术后24、48 h的肌钙蛋白I（cTnI）、C反应蛋白（CRP）、白细胞介素-6（IL-6）、丙二醛（MDA）、超氧化物歧化酶（SOD）、内皮型一氧化氮合成酶（eNOS）、诱导型一氧化氮合成酶（iNOS）浓度，以及术后48 h D-二聚体、纤维蛋白降解产物（FDP）浓度。记录心肌损伤（cTnI≥0.2 μg/L）以及术后30 d内的主要心血管不良事件的发生情况。
结果 与C组比较，RIPC组术后24、48 h cTnI明显降低，术后24 h CRP、IL-6明显降低，术后24、48 h MDA明显降低，术后48 h eNOS、iNOS明显升高，D-二聚体、FDP浓度明显降低（P＜0.05）。两组心肌损伤、术后30 d主要心血管不良事件的发生率差异无统计学意义。
结论 远端缺血预处理能降低胃肠道恶性肿瘤根治术后早期心肌损伤标志物cTnI的释放，减轻术后炎症反应、氧化应激、高凝状态并改善血管内皮功能，但不能降低心肌损伤以及术后30 d内主要心血管不良事件的发生率。     

星型胶质细胞和小胶质细胞在1型糖尿病小鼠外周神经病变中的作用

目的 观察星形胶质细胞和小胶质细胞标志物在1型糖尿病外周神经病变小鼠脊髓中的表达变化。
方法 SPF级健康雄性C57BL/6小鼠30只,6周龄,体重18~22 g,采用随机数字表法分为两组：对照组（C组）和糖尿病组（DM组）。DM组采用链脲佐菌素（STZ）（100 mg/kg,连续2 d腹腔注射）制备1型糖尿病小鼠模型,C组给予同等剂量柠檬酸钠缓冲液连续2 d。记录两组小鼠造模前、造模后1、2、4、6、8、10周的体重、随机血糖、机械缩足反应阈（MWT）、热缩足潜伏期（TWL）。生化检测分别选取C组和DM组1周、10周的脊髓。采用Western blot法测定L4—L6脊髓脂肪酸结合蛋白7（FABP7）、星形胶质细胞特异性标记物胶质纤维酸性蛋白（GFAP）、小胶质细胞标记物（CD11b、iba1）表达量,Elisa法测定小鼠脊髓组织中肿瘤坏死因子α（TNF-α）、IL-10浓度,免疫组化法测定足底表皮神经纤维密度（IENFD）。
结果 与C组比较,DM组造模后2、4、6、8、10周体重、MWT明显降低（P＜0.05或P＜0.01）,造模后1、2、4、6、8、10周血糖明显升高（P＜0.01）,造模后4、6、8、10周TWL明显延长（P＜0.05或P＜0.01）;造模后1周FABP7和GFAP表达量明显升高（P＜0.05）;造模后10周FABP7、CD11b、iba1表达量明显升高（P＜0.05）;造模后10周脊髓组织中IL-10、TNF-α浓度明显升高（P＜0.05）;造模后10周IENFD明显降低（P＜0.05）。
结论 糖尿病模型小鼠造模后1周脊髓中星形胶质细胞活化但小胶质细胞无明显改变,而造模后10周星形胶质细胞已恢复正常但小胶质细胞活化,1型糖尿病外周神经病变中星型胶质细胞较小胶质细胞更早的激活。     

咪达唑仑减轻升高透明平台法诱发的小鼠术前焦虑

目的 探索利用升高透明平台法建立动物焦虑行为的效果和咪达唑仑对减轻利用升高透明平台法诱导的小鼠焦虑行为的作用。
方法 雄性C57BL/6J小鼠39只，2月龄，体重20～24 g。将小鼠随机分为三组：对照组（C组）、升高平台应激组（E组）和升高平台应激+咪达唑仑组（EM组），每组13只。C组正常饲养；E组每天接受2次（每次持续3 min）升高透明平台应激，连续1周；EM组小鼠除接受与E组相同的升高透明平台应激外，于建模结束后第1天和第3天的行为学测试前30 min腹腔注射咪达唑仑0.5 mg/kg。建模结束后，采用旷场实验与新环境进食抑制实验检测小鼠进入旷场中心区次数、中心区停留时间、中心区运动距离和进食潜伏期。采用ELISA法检测小鼠血清皮质酮（Cor）浓度及海马组织中γ-氨基丁酸（GABA）浓度。
结果 与C组比较，E组中心区进入次数明显减少（P＜0.05）、中心区停留时间和中心区运动距离明显缩短（P＜0.05），进食潜伏期明显延长（P＜0.05），血清Cor浓度明显升高（P＜0.05），海马组织GABA浓度明显降低（P＜0.05）。与E组比较，EM组中心区进入次数明显增加(P<0.05)，中心区时间明显延长（P＜0.05），进食潜伏期明显缩短（P＜0.05），血清Cor浓度明显降低（P＜0.05），海马组织中GABA浓度明显升高（P＜0.05）。
结论 升高透明平台应激可诱导小鼠产生焦虑样行为，咪达唑仑可改善小鼠焦虑样行为，降低血清Cor浓度，升高海马组织GABA浓度。     

肺部超声在支气管封堵单肺通气中对判断肺隔离的影响

目的 探讨肺部超声在支气管封堵单肺通气中判断肺隔离的效果。
方法 选取全身麻醉下左支气管封堵单肺通气下行左肺癌根治术的患者60例，年龄46~68岁，BMI 18~26 kg/m²，ASA Ⅰ或Ⅱ级。采用随机数字法将患者分为三组：听诊组（A组）、纤维支气管镜组（F组）和超声组（U组），每组20例。置入支气管封堵导管后，A组采用听诊器听诊呼吸音，F组采用纤维支气管镜观察套囊位置，U组采用超声观察肺部超声影像判断肺隔离。观察三种方法判断肺隔离时间、肺萎陷满意度和术中封堵导管套囊位置的调整次数，观察三组诱导前（T₀）、诱导后（T₁）、定位时（T₂）、单肺通气时（T₃）、单肺通气 30 min（T₄）时的HR、MAP、CVP。
结果 与A组比较，F组和U组判断肺隔离时间明显缩短（P＜0.05或P＜0.01），肺萎陷满意度明显升高（P＜0.01或P＜0.001），术中封堵导管套囊位置的调整次数明显降低（P＜0.001）。F组和U组判断肺隔离效果时间、肺萎陷满意度、术中封堵导管套囊位置的调整次数差异无统计学意义。与T₀时比较，T₂时F组HR明显增快、MAP明显升高（P＜0.05），与A组和U组比较，T₂时F组HR明显增快、MAP明显升高（P＜0.01或P＜0.001）。
结论 肺部超声用于判断单肺通气肺隔离效果优于听诊法，其判断效果与纤维支气管镜检查相近，且超声对于血流动力学的影响较纤维支气管镜小。     

不同剂量阿芬太尼对老年患者快速顺序诱导气管插管心血管反应的影响

目的 比较不同剂量阿芬太尼对老年患者快速顺序诱导气管插管心血管反应的影响。
方法 选择2022年3—9月行气管插管全麻老年患者96例，男47例，女49例，年龄65～80岁，BMI 18～24 kg/m²，ASA Ⅰ或Ⅱ级。采用随机数字表法分为四组：阿芬太尼10 μg/kg组（A组）、阿芬太尼15 μg/kg组（B组）、阿芬太尼20 μg/kg组（C组）和阿芬太尼25 μg/kg组（D组），每组24例。记录麻醉诱导前、气管插管后1、5 min的HR、MAP，同时抽取患者静脉血3 ml，检测血浆中去甲肾上腺素（NE）和皮质醇（Cor）的浓度、超声测量心脏指数（CI）、心脏射血分数（EF）。记录麻醉诱导后至气管插管后5 min高血压、低血压、心动过缓、心动过速的发生情况。
结果 与麻醉诱导前比较，A组和B组在气管插管后1、5 min HR明显增快，MAP、NE和Cor浓度明显升高，CI和EF明显降低（P＜0.05）；C组和D组气管插管后1 min HR明显增快，MAP明显升高，D组插管后5 min HR明显减慢，MAP、血浆NE和Cor浓度、CI和EF明显降低（P＜0.05）。与A组比较，C组和D组气管插管后1、5 min HR明显减慢，血浆NE和Cor浓度明显降低，气管插管后1 min CI和EF明显升高，高血压和心动过速发生率明显降低（P＜0.05）；D组插管后5 min CI和EF明显降低，低血压和心动过缓发生率明显升高（P＜0.05）。
结论 阿芬太尼20 μg/kg用于老年患者快速顺序诱导气管插管，可有效抑制插管引起的剧烈心血管反应，同时避免心血管系统的抑制，血流动力学更平稳。     

鞘内注射Maresin 1对骨癌痛小鼠痛行为学和脊髓胶质细胞活化的影响

目的 探讨鞘内注射Maresin 1对骨癌痛（BCP）小鼠痛行为学和脊髓胶质细胞活化的影响。
方法 实验一：选择清洁级健康雄性C57BL/6小鼠28只,4～6周龄,体质量18～22 g。随机分为两组：假手术1组（S1组）和BCP1组（B1组）,每组14只。 B1组小鼠股骨髓腔内注射含有2×105个Lewis肺癌细胞的PBS溶液20 μl,建立骨癌痛小鼠模型;S1组仅注射PBS溶液20 μl。造骨癌痛模型（造模）前1 d、造模后3、7、10、14和21 d时随机取6只测定机械缩足阈值（MWT）和热缩足潜伏期（TWL）。B1组和S1组于造模后7、14和21 d时随机取4只小鼠处死,采用Western blot法检测脊髓胶质纤维酸性蛋白（GFAP）和离子钙结合适配器分子1（Iba1）含量。实验二：清洁级健康雄性C57BL/6小鼠36只,随机分为三组：假手术2组（S2组）、BCP2组（B2）组和Maresin 1（M）组,每组12只。S2组注射PBS溶液20 μl;B2和M组造骨癌痛小鼠模型。M组于造模后14～16 d时连续3 d鞘内注射Maresin 1 50 ng/5 μl。S2组、B2组和M组于造模后14～18 d时随机取6只测定MWT和TWL。于造模后18 d行为学测试完成后处死小鼠,采用Western blot和免疫荧光法检测脊髓GFAP和Iba1含量。ELISA法检测脊髓IL-1β、IL-6和TNF-α浓度。
结果 实验一：与S1组比较,B1组造模后7、10、14和21 d MWT明显降低,TWL明显缩短,造模后7、14和21 d脊髓GFAP和Iba1含量明显升高（P＜0.05）。实验二：与S2组比较,B2组造模后18 d脊髓GFAP和Iba1含量明显升高,平均荧光强度明显增强,脊髓IL-1β、IL-6和TNF-α浓度明显升高（P＜0.05）。与B2组比较,M组造模后15～18 d时MWT明显升高,TWL明显延长（P＜0.05）,造模后18 d脊髓GFAP和Iba1含量明显降低,平均荧光强度明显减弱（P＜0.05）,脊髓IL-1β、IL-6和TNF-α浓度明显降低（P＜0.05）。
结论 鞘内注射Maresin 1可能通过抑制脊髓胶质细胞活化,减轻神经炎症反应,缓解骨癌痛。     

经皮穴位电刺激预处理对蛛网膜下腔阻滞肛肠手术后尿潴留的影响

目的 评价经皮穴位电刺激（TEAS）预处理对蛛网膜下腔阻滞（腰麻）肛肠手术后尿潴留的影响。
方法 选择择期在腰麻下行肛肠手术的患者195例,男122例,女73例,年龄18～64岁,BMI 18～28 kg/m²,ASA Ⅰ或Ⅱ级。采用随机数字表法将患者随机分为三组：腰麻前TEAS预处理组（A组）、手术结束时TEAS组（B组）和对照组（C组）,每组65例。A组于腰麻前经皮电刺激中极穴（RN3）、气海穴（RN6）、关元穴（RN4）、关元俞穴（BL26）和八髎穴（BL31-34）,疏密波频率2/100 Hz,电流强度6～10 mA,刺激时间30 min;B组于手术结束后立刻选取与A组相同的穴位、频率、刺激强度及刺激时间;C组不予电刺激。记录首次排尿时间、首次排尿量、首次排尿等待时间以及术后当晚小腹胀满感评分以及术后尿潴留和术后因尿潴留导尿情况。
结果 与A组比较,B组首次排尿量明显减少（P＜0.05）;C组首次排尿时间、首次排尿等待时间明显延长,首次排尿量明显减少,术后当晚小腹胀满感评分明显升高（P＜0.05）。与B组比较,C组首次排尿时间明显延长（P＜0.05）。与A组比较,B组和C组术后尿潴留发生率明显升高（P＜0.05）,C组因尿潴留导尿率明显升高（P＜0.05）。
结论 腰麻前给予经皮穴位电刺激预处理可明显降低肛肠手术后尿潴留的发生率,能更好地保护膀胱功能,促进排尿功能的恢复。     

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.