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1.
摘要 目的:研究白藜芦醇对脊髓损伤(Spinal cord injury, SCI)小鼠脊髓组织神经元凋亡和凋亡相关蛋白表达的影响。方法:21只雌性C57BL/6小鼠,6-8周龄,随机分为三组:Sham组(假手术对照组),SCI组(脊髓损伤模型)和Resveratrol组(白藜芦醇治疗的脊髓损伤模型),每组7只。通过Basso小鼠量表(BMS)评估小鼠后肢运动功能、HE染色评估小鼠脊髓病变面积、尼氏染色检测脊髓组织神经元数目、TUNEL染色检测凋亡细胞数目。通过酶联免疫试剂盒检测脊髓组织髓过氧化物酶(myeloperoxidase,MPO)、肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)、白细胞介素(interleukin, IL)-6和IL-8蛋白表达水平。通过免疫印迹法检测脊髓组织凋亡相关蛋白Fas、FasL、caspase 3和caspase 8表达水平。结果:与Sham组小鼠相比,SCI模型小鼠脊髓组织病变面积和MPO活性均显著增加(P<0.05),但经白芦藜醇治疗后的Resveratrol组SCI小鼠脊髓组织病变面积和MPO活性较SCI组小鼠显著降低(P<0.05)。与Sham组小鼠相比,SCI模型小鼠BMS评分显著降低(P<0.05),但经白芦藜醇治疗后的Resveratrol组SCI小鼠BMS评分较SCI组小鼠显著升高(P<0.05)。与Sham组小鼠相比,SCI模型小鼠脊髓组织神经元丢失和凋亡均显著增加(P<0.05),但经白芦藜醇治疗后的Resveratrol组SCI小鼠脊髓组织病神经元丢失和凋亡较SCI组小鼠显著降低(P<0.05)。与Sham组小鼠相比,SCI模型小鼠脊髓组织Fas、FasL、caspase 3、caspase 8、TNF-α、IL-6和IL-8蛋白表达水平均显著升高(P<0.05),但经白芦藜醇治疗后均显著降低(P<0.05)。结论:白芦藜醇可显著降低脊髓损伤小鼠脊髓组织神经元凋亡,其机制可能与抑制脊髓损伤小鼠脊髓组织炎症和炎症引起的凋亡蛋白表达有关。 相似文献
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摘要 目的:心肌缺血再灌注损伤常常会导致心肌的凋亡和坏死,有研究表明胸段硬膜外麻醉(Thoracic epidural anesthesia,TEA)在心肌缺血再灌注损伤中的作用,因此,我们建立了心肌缺血损伤模型和胸段硬膜外麻醉模型来探讨胸段硬膜外麻醉对大鼠心肌缺血再灌注损伤(Myocardial ischemia-reperfusion injury,I/R)的影响。方法:SPF小鼠60只,随机分为正常组、I/R组及TEA组,分别采用TTC、HE染色、免疫组化、Western-blot等方法检测各组小鼠心肌组织及相关蛋白表达情况。结果:1.与正常组比较,I/R组和TEA组有较高的心肌梗死面积。与I/R组相比,TEA组心肌梗死面积明显减少,差异具有统计学意义(P<0.05)。2.TEA组上调了Akt、Hes1和Bcl-2的蛋白表达,下调了Notch 1、DTNA、BAX和HIF-1α的表达。结论:TEA对小鼠心肌缺血再灌注损伤具有保护作用。 相似文献
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摘要 目的:探讨人参皂苷Rg3(ginsenoside Rg3,Rg3)对脓毒症介导的心肌损伤的作用效果及机制。方法:本研究通过对小鼠进行盲肠结扎穿孔手术的方法构建脓毒症模型。32只BALB/c小鼠随机分为假手术组(Sham组)、脓毒症组(CLP组)、人参皂苷Rg3治疗组(Rg3+CLP组)以及自噬抑制剂干预组(3-MA+Rg3+CLP组),每组8只。术后18 h分别留取各组小鼠血浆及心肌组织。通过ELISA方法检测白细胞介素-1β(IL-1β)、白细胞介素-18(IL-18)、乳酸脱氢酶(LDH)、肌酸激酶同工酶MB(CK-MB)及半胱氨酸蛋白酶-3(Caspase-3)表达水平。通过HE染色观察心肌组织形态结构的变化。应用Western-blot方法检测自噬及NLRP3炎性小体相关蛋白(NLRP3、ASC、Caspase-1)的表达。结果:与Sham组相比,CLP组小鼠心肌组织结构紊乱,炎性细胞浸润明显。另外,Caspase-3活性增加,NLRP3炎性小体相关蛋白(NLRP3、ASC、Caspase-1)表达升高,差异均有统计学意义(P<0.05)。与CLP组相比,外源应用Rg3组小鼠心肌组织炎性细胞浸润减少,并且Caspase-3活性降低,NLRP3炎性小体相关蛋白表达下降,差异有统计学意义(P<0.05),而部分自噬相关蛋白表达升高。应用自噬抑制剂后,较单纯应用Rg3组,心肌组织损伤明显,而NLRP3炎性小体活性增加,差异有统计学意义(P<0.05)。结论:脓毒症时NLRP3炎性小体激活,释放大量的细胞因子,进而导致心肌损伤。而Rg3治疗后,可以调节心肌细胞自噬,抑制NLRP3炎性小体激活,进而减轻细胞因子对心肌细胞的损伤。本研究表明Rg3可能通过调节心肌自噬,抑制NLRP3炎性小体的激活,进而减轻脓毒症时心脏的损伤。 相似文献
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摘要 目的:基于蛋白激酶R样内质网激酶(PERK)/核因子E2相关因子2(Nrf2)/血红素氧合酶-1(HO-1)信号通路探究瑞马唑仑对心肌缺血再灌注损伤(MIRI)大鼠铁死亡的影响。方法:将90只SD大鼠随机分为假手术(Sham)组、MIRI组、低剂量-瑞马唑仑组(L-瑞马唑仑组,5 mg/kg)、高剂量-瑞马唑仑组(H-瑞马唑仑组,20 mg/kg)、H-瑞马唑仑+PERK抑制剂组(瑞马唑仑20 mg/kg+GSK2606414 1 mg/kg),每组18只。采用结扎冠状动脉左前降支(LAD)0.5 h、再灌注2 h制备MIRI大鼠模型,于再灌注2 h后即刻尾静脉注射给药,再灌注24 h后进行组织取材。酶联免疫吸附(ELISA)法检测血清心肌损伤标志物[肌酸激酶同工酶(CK-MB)、心肌肌钙蛋白I(cTnI)]水平;HE染色观察心肌组织病理改变;Tunel染色检测心肌细胞凋亡;透射电镜观察心肌细胞超微结构变化;检测心肌组织中铁死亡相关标志物[铁、活性氧(ROS)、谷胱甘肽(GSH)、丙二醛(MDA)]水平;蛋白质印迹法(Western Blot)检测心肌组织中PERK/Nrf2/HO-1信号通路相关蛋白表达。结果:与Sham组相比,MIRI组心肌结构受损,纤维排列紊乱,线粒体呈现显著的铁死亡特征(膜固缩,膜密度增加,嵴减少),血清中CK-MB、cTnI水平,心肌细胞凋亡率及心肌组织中铁、ROS、MDA水平升高(P<0.05),心肌组织中GSH水平及p-PERK/PERK、核Nrf2/Nrf2、HO-1蛋白表达降低(P<0.05);与MIRI组相比,L-瑞马唑仑组和H-瑞马唑仑组心肌组织上述病理改变明显减轻,血清CK-MB、cTnI水平,心肌细胞凋亡率及心肌组织中铁、ROS、MDA水平降低(P<0.05),心肌组织中GSH水平及p-PERK/PERK、核Nrf2/Nrf2、HO-1蛋白表达升高(P<0.05);与H-瑞马唑仑组相比,H-瑞马唑仑+PERK抑制剂组心肌组织上述病理改变加重,血清CK-MB、cTnI水平,心肌细胞凋亡率及心肌组织中铁、ROS、MDA水平升高(P<0.05),心肌组织中GSH水平及p-PERK/PERK、核Nrf2/Nrf2、HO-1蛋白表达降低(P<0.05)。结论:瑞马唑仑可通过抑制铁死亡减轻大鼠MIRI,可能通过激活PERK/Nrf2/HO-1信号通路而实现。 相似文献
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摘要 目的:探讨下调miR-223表达对脓毒症心肌病(SCM)小鼠心肌的保护作用及其机制。方法:按随机数字表法将27只8-10 周龄SPF级雄性C57BL/6小鼠分配至SCM模型(0 h,6 h,12 h,18 h,24 h)时相组、Normal组、SCM组、miR-223 antagomir NC组、miR-223 antagomir组,每组3只。腹腔注射脂多糖(lipopolysaccharide, LPS)15 mg/kg构建SCM小鼠模型。miR-223 antagomir NC组与miR-223 antagomir组分别于建模前连续3天鼠尾静脉注射miR-223 antagomir NC、miR-223 antagomir预处理。采用反转录-聚合酶链反应(RT-PCR)研究SCM模型各个时相组小鼠心肌组织miR-223的表达情况。采用苏木素伊红(HE)染色法观察Normal组、SCM组、miR-223 antagomir NC组和miR-223 antagomir组小鼠心肌病理形态变化。采用酶联免疫吸附实验(ELISA)测定Normal组、SCM组、miR-223 antagomir NC组和miR-223 antagomir组小鼠血清cTnI、BNP、CK-MB、IL-6、IL-1β、TNF-α的含量并进行相关性分析。结果:SCM模型时相组小鼠随刺激时间延长,心肌组织miR-223表达水平逐渐升高。与Normal组比较,SCM组、miR-223 antagomir NC组、miR-223 antagomir组小鼠心肌组织出现不同程度损伤;血清心肌损伤标记物cTnI、BNP、CK-MB及炎性因子IL-6、IL-1β、TNF-α的表达水平均上升,差异具有统计学意义(P<0.05);与SCM组比较,miR-223 antagomir NC组各项指标相差不大,差异均无统计学意义(P>0.05);miR-223 antagomir组小鼠心肌组织病理损伤程度有所减轻,心肌损伤标记物cTnI、BNP、CK-MB及炎性因子IL-6、IL-1β、TNF-α水平下降,差异具有统计学意义(P<0.05)。相关性分析结果显示小鼠miR-223表达与心肌损伤标记物cTnI、BNP、CK-MB及炎性因子IL-6、IL-1β、TNF-α的表达呈正相关。结论:下调miR-223表达可通过减轻炎症反应对SCM小鼠心肌产生保护作用。 相似文献
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摘要 目的:本研究旨在探究黄芪甲苷(Astragaloside IV,Ast-IV)在缺血再灌注(ischemia-reperfusion,I/R)大鼠模型中的保护作用,并讨论黄芪甲苷在抑制I/R诱导心肌细胞凋亡过程中的作用。方法:通过左冠状动脉前降支结扎构建I/R大鼠模型;将40只SD大鼠分为4组:假手术组(Sham组)、模型组(I/R组)、黄芪甲苷干预组(Ast组)和黄芪甲苷+LY294002干预组(Ast+LY组)。使用试剂盒测定血清中心脏功能障碍标记物CPK、ALT、LDH和tropornin-T的表达水平;通过HE染色和TUNEL分别检测心肌组织病理学变化和心肌细胞凋亡情况;通过超氧化物荧光探针染色检测细胞内ROS水平;通过ELISA试剂盒测定心肌组织MDA、GSH和GSH-PX含量;免疫组织化学检测SOD2和HO-1蛋白表达水平,分析心肌氧化应激状态;通过Western blot检测PI3K、p-Akt、Akt、p-eNOS、eNOS、caspase-3、Bax和Bcl-2蛋白表达水平变化。结果:Ast组大鼠血浆CPK、ALT、LDH和tropornin-T酶活性均明显低于I/R组(P<0.05)。Ast组大鼠心肌纤维断裂,心肌细胞坏死和炎性细胞浸润等病变程度均低于I/R组。Ast组大鼠TUNEL阳性细胞数低于I/R组(P<0.05)。相较于I/R组,Ast组大鼠Caspase3和Bax表达水平均明显下调,Bcl-2和PI3K蛋白表达水平上调,p-Akt/Akt和p-eNOS/eNOS比值均显著上调(P<0.05)。Ast组大鼠DHE荧光强度显著低于Ast+LY组(P<0.05)。与I/R组相比,Ast组大鼠心肌组织中MDA含量降低,GSH、GSH-PX、SOD2和HO-1表达水平升高(P<0.05);与Ast组相比,Ast+LY组大鼠心肌组织中MDA含量升高,GSH、GSH-PX、SOD2和HO-1表达水平降低(P<0.05)。结论:黄芪甲苷通过激活PI3K/Akt信号通路,抑制心肌细胞氧化应激反应,从而减少I/R诱导大鼠心肌细胞凋亡,缓解I/R后大鼠心肌损伤。 相似文献
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摘要 目的:探讨瑞舒伐他汀联合缺血后处理对糖尿病小鼠心肌的作用并分析其保护作用的机制。方法:应用高脂高糖饮食的方法构建2型糖尿病小鼠动物模型,随机分为假手术组(sham组)、缺血/再灌注组(I/R组)、缺血后处理组(IpostC组)及瑞舒伐他汀联合缺血后处理组(RPO+IpostC组),每组10只。分析各组小鼠低氧诱导因子-1α(HIF-1α)、诱导型一氧化氮合酶(iNOS)蛋白表达及血浆炎症因子、血清一氧化氮(NO)水平变化,观察各组小鼠心肌梗死面积、心肌组织HE染色结构变化。结果:与I/R组、IPostC组相比,RPO+IpostC组HIF-1α,iNOS蛋白表达显著上调(P<0.05);与IpostC 组相比,RPO+ IpostC组小鼠血清NO和血浆IL-1β、IL-6、TNF-α水平均明显降低,血浆IL-10升高(P<0.05);经显微镜观察显示,sham组小鼠的心肌细胞HE染色结构正常,RPO+IpostC组小鼠心肌细胞HE染色后损伤相对较小;与I/R组相比,IpostC组和RPO+IpostC组小鼠缺血面积(AAR/LV)、梗死面积(IRR/AAR)均明显减小,且RPO+IpostC组小鼠AAR/LV、IRR/AAR最小(P<0.05)。结论:瑞舒伐他汀联合缺血后处理可以通过对糖尿病小鼠HIF-1α-iNOS信号通路进行调节,进而上调HIF-1α、iNOS蛋白表达,减轻炎症反应,降低心肌细胞缺血再灌注损伤,保护心肌。 相似文献
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摘要 目的:探讨右美托咪定(DEX)对糖尿病小鼠心肌缺血再灌注损伤的保护作用及可能分子机制。方法:将60只8周龄的SPF级C57BL小鼠高脂喂养6周,第7周通过腹腔注射链脲佐菌素(STZ)45 mg/kg/天,1次/天,连续5天,建立2型糖尿病模型,建模后采用随机数字表法分为假手术组(sham组)、缺血再灌注组(I/R组)、缺氧诱导因子-1α(HIF-1α)抑制剂2ME2组(2ME2组)、DEX组、DEX+2ME2组(DM组),每组12只。假手术组仅切开皮肤后缝合,其余四组开胸结扎冠状动脉左前降支,缺血60 min后松开结扎线结,再灌注120 min建立缺血再灌注损伤模型。于再灌注120 min时抽取小鼠腹主动脉血,ELISA检测血清肌钙蛋白I(cTnI)、白介素-1β(IL-1β)、肿瘤坏死因子-α(TNF-α)的浓度,随后处死小鼠,分离左心室,HE染色观察心肌组织形态结构,Western blot检测HIF-1α、nod样受体蛋白3(NLRP3)的表达量,再灌注24 h时超声心动图评估心功能。结果:与sham组相比,I/R组、2ME2组、DEX组、DM组cTnI、IL-1β,TNF-α浓度明显升高,心肌组织结构紊乱,心肌纤维断裂增加,心肌细胞明显肿胀,炎性细胞浸润增加,心肌组织NLRP3表达量显著增加,每搏量(SV)、射血分数(EF)%、短轴缩短率(FS)%明显下降(P<0.05);与I/R组相比,DEX组、DM组HIF-1α表达量明显增加,NLRP3表达明显降低,cTnI、IL-1β,TNF-α浓度明显下降,心肌组织结构明显改善,炎性细胞浸润明显减少,SV,EF、FS明显升高(P<0.05);与DEX组相比,DM组HIF-1α表达量明显降低,NLRP3表达量明显增加,cTnI、IL-1β、TNF-α浓度明显增加,心肌组织结构紊乱,心肌纤维断裂增加,心肌细胞明显肿胀,炎性细胞浸润增加,SV,EF、FS明显降低(P<0.05)。结论:DEX可能通过上调心肌组织HIF-1α的表达,抑制NLRP3炎性体的激活,减轻心脏炎症反应,改善糖尿病小鼠心肌缺血再灌注损伤。 相似文献
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摘要 目的:探讨刺槐素对大鼠心肌缺血再灌注损伤(MIRI)的作用以及可能的作用机制。方法:对24只Sprague-Dawley (SD)大鼠进行随机分组,分为:假手术组、模型组、刺槐素给药组、刺槐素+AG490给药组,每组6只,通过结扎冠状动脉左前降支,缺血30 min,再灌注120 min复制心肌缺血再灌注损伤模型。利用氯化三苯基四氮唑测定心肌梗死面积,紫外分光光度计和酶联免疫法检测血清中肌酸激酶同工酶(CK-MB)、乳酸脱氢酶(LDH)的活性,蛋白印迹法分别检测心肌组织中Bcl-2、Bax、Stat3和p-Stat3蛋白相对表达水平。结果:与假手术组比较,模型组大鼠血清中CK-MB、LDH活性明显升高(P<0.01),心肌梗死面积百分比显著增加(P<0.01),p-Stat3/Stat3比率、Bcl-2/Bax比率显著下降(P<0.01);与模型组相比,刺槐素给药组中CK-MB、LDH的活性,以及心肌梗死面积百分比显著降低(P<0.01),Bcl-2/Bax比率和p-Stat3/Stat3比率显著提高(P<0.05)。然而在刺槐素+AG490药物组中刺槐素对于受损心肌的保护作用被AG490消除。结论:刺槐素可减轻MIRI大鼠心肌损伤,发挥心肌保护作用,其机制可能与活化Jak2/Stat3信号通路进而抑制心肌细胞凋亡有关。 相似文献
10.
摘要 目的:探讨粒细胞-巨噬细胞集落刺激因子(GM-CSF)基因转染的骨髓间充质干细胞(BMSCs)对脓毒症小鼠血管内皮损伤、凝血功能及炎症因子的影响。方法:将60只SD小鼠分为Sham组、模型(Model)组、BMSCs组、GM-CSF-BMSCs组,每组15只,采用盲肠结扎穿孔法制备小鼠脓毒症模型。实时荧光定量聚合酶链式反应(qRT-PCR)检测细胞GM-CSF基因表达;记录24 h小鼠尾出血时间;检测血浆凝血酶原时间(PT)、活化部分凝血酶原时间(APTT)、凝血酶时间(TT)、纤维蛋白原(Fib)水平;ELISA法检测血清白细胞介素(IL)-6、肿瘤坏死因子(TNF)-α、IL-1、IL-10水平;苏木精-伊红(HE)染色观察血管组织形态;TUNEL法检测血管内皮细胞凋亡;Western blot检测血管组织因子(TF)、组织因子途径抑制物(TFPI)、抗凝血酶(ATⅢ)、血管细胞粘附因子1(VCAM1)、蛋白酶激活受体(PAR1)蛋白表达。结果:与CK组BMSCs比较,Transfection组BMSCs细胞GM-CSF mRNA表达显著升高(P<0.05)。与Sham组比较,Model组小鼠血管形态结构有明显的损伤,小鼠尾出血时间、Fib含量、血清IL-10水平和血管内皮组织ATⅢ蛋白表达显著降低,PT、APTT、TT时间、血清IL-6、TNF-α、IL-1水平、凋亡率、血管内皮组织TF、TFPI、VCAM1、PAR1蛋白表达显著升高(P<0.05);与Model组比较,BMSCs组和GM-CSF-BMSCs组小鼠血管形态结构损伤明显减轻,小鼠尾出血时间、Fib含量、血清IL-10水平和血管内皮组织ATⅢ蛋白表达显著升高,PT、APTT时间、血清IL-6、TNF-α、IL-1水平、凋亡率、血管内皮组织TF、TFPI、VCAM1、PAR1蛋白表达显著降低(P<0.05);GM-CSF-BMSCs组各项检测指标优于BMSCs组(P<0.05)。结论:GM-CSF转染的BMSCs可减轻脓毒症小鼠炎症反应和血管内皮细胞损伤,改善凝血功能。 相似文献
11.
为了获得高产石杉碱甲(Huperzine A,Hup A)的蛇足石杉[Huperzia serrata(Thunb.)Trev.]叶状体,对H_2O_2诱变后的叶状体进行了研究。结果表明,诱变后叶状体株系的Hup A含量显著提高,并获得高产株系SH42,其相对生长率和Hup A含量分别达到4499.28%和261.17μg g~(–1) DW,比起始叶状体分别提高了2.35倍和2.43倍;且株系间可溶性蛋白质谱带和SOD同工酶谱均存在差异,经过连续9代培养,变异叶状体可以稳定遗传。因此,H_2O_2对叶状体细胞具有良好的诱变效应,可以用于筛选高产Hup A株系。 相似文献
12.
Data from microscopic morphology, single-spore cultures, and DNA analyses of teleomorphs and anamorphs support the recognition of five species of Prosthecium with Stegonsporium anamorphs on Acer: P. acerinum sp. nov., the teleomorph of S. acerinum; P. acerophilum comb. nov., formerly known as Dictyoporthe acerophila; P. galeatum comb. nov., originally described as Massaria galeata; P. opalus sp. nov.; and P. pyriforme sp. nov., the teleomorph of S. pyriforme s. str. The morphology of both type specimens and freshly collected material was investigated. The teleomorphs have brown ellipsoidal ascospores with five distosepta and often a longitudinal distoseptum. The anamorphs of all species described here belong to Stegonsporium; their connection to the Prosthecium teleomorphs was demonstrated by morphology and DNA sequences of single spore cultures derived from both ascospores and conidia. The anamorphs and teleomorphs of all five Prosthecium species are described and illustrated by LM images, and a key to these species is provided. As perceived from this work, S. pyriforme is restricted to Europe and does not occur in North America, whereas S. acerinum is restricted to North America, not found in Europe. The host associations given in the literature are revised and evidence is provided that only A. opalus, A. pseudoplatanus, and A. saccharum are confirmed hosts of Prosthecium with Stegonsporium anamorphs. Molecular phylogenetic analyses of tef1, ITS rDNA, and partial nuLSU rDNA sequences confirm that the species with Stegonsporium anamorphs are closely related to P. ellipsosporum, the generic type species. Stilbospora macrosperma is confirmed as the anamorph of P. ellipsosporum by DNA data of single spore isolates obtained from both ascospores and conidia. 相似文献
13.
David F. Farr M. Catherine Aime Amy Y. Rossman Mary E. Palm 《Mycological Research》2006,110(12):1395-1408
Species of Colletotrichum cause diseases on a wide range of hosts, frequently infecting plants in the Agavaceae (monocotyledons: Liliales). Three species of Colletotrichum restricted to the Agavaceae were detected through morphological studies of specimens and molecular sequence analyses of the LSU of the nu-rDNA and the ITS region of the nu-rDNA from cultures. Colletotrichum agaves on Agave is fully described and illustrated. Colletotrichum dracaenophilum is described as a new species for isolates having long conidia and occurring on Dracaena sanderiana from China. Colletotrichum phormii and Glomerella phormii are determined to be the correct scientific names for the asexual and sexual states, respectively, of a species commonly referred to as C. rhodocyclum and G. phacidiomorpha occurring mainly on Phormium. In addition, C. gloeosporioides and C. boninense were isolated from plants in the Agavaceae. All species of Colletotrichum described on Agavaceae were evaluated based on type specimens. A key to the five species of Colletotrichum on Agavaceae is included. This paper includes one new species, Colletotrichum dracaenophilum, and three new combinations, Colletotrichum phormii, Glomerella phormii, and Phaeosphaeriopsis phacidiomorpha. 相似文献
14.
15.
Rawal R Chawla S Chauhan N Dahiya T Pundir CS 《International journal of biological macromolecules》2012,50(1):112-118
A chitosan-glutaraldehyde crosslinked uricase was immobilized onto Prussian blue nanoparticles (PBNPs) absorbed onto carboxylated multiwalled carbon nanotube (c-MWCNT) and polyaniline (PANI) layer, electrochemically deposited on the surface of Au electrode. The nanohybrid-uricase electrode was characterized by scanning electron microscopic (SEM), Fourier transform infrared spectroscopy (FTIR) and cyclic voltammetry. An amperometric uric acid biosensor was fabricated using uricase/c-MWCNT/PBNPs/Au electrode as working electrode, Ag/AgCl as standard and Pt wire as auxiliary electrode connected through a potentiostat. The biosensor showed optimum response within 4 s at pH 7.5 and 40 °C, when operated at 0.4 V vs. Ag/AgCl. The linear working range for uric acid was 0.005-0.8 mM, with a detection limit of 5 μM. The sensor was evaluated with 96% recovery of added uric acid in sera and 4.6 and 5.4% within and between batch of coefficient of variation respectively and a good correlation (r = 0.99) with standard enzymic colorimetric method. This sensor measured uric acid in real serum samples. The sensor lost only 37% of its initial activity after its 400 uses over a period of 7 months, when stored at 4 °C. 相似文献
16.
Background
The evolution of alternatively spliced exons (ASEs) is of primary interest because these exons are suggested to be a major source of functional diversity of proteins. Many exon features have been suggested to affect the evolution of ASEs. However, previous studies have relied on the K A /K S ratio test without taking into consideration information sufficiency (i.e., exon length > 75 bp, cross-species divergence > 5%) of the studied exons, leading to potentially biased interpretations. Furthermore, which exon feature dominates the results of the K A /K S ratio test and whether multiple exon features have additive effects have remained unexplored. 相似文献17.
18.
Isabella Lois 《Inorganica chimica acta》2007,360(8):2686-2696
A comparative structural study on sodium and potassium N-chloroarenesulfonamidates has been carried out using X-ray diffraction and IR spectroscopy as experimental techniques. As shown by crystallographic studies, the sodium ions tend to incorporate more water oxygen atoms in their coordination spheres than the potassium ions, while the potassium congeners prefer the interaction with sulfonamidate moieties. The marked dissimilarity between the compositions of the coordination spheres as well as the different tendency of the sodium and potassium salts to absorb moisture from the air have been attributed to the different sizes of the sodium and potassium ions. The opposite shifts of the νas(SO2) and ν(SN) bands upon dehydration have been ascribed to an increased polarization of the sulfonyl group by the metal centers. Based on IR spectroscopic observations, a weakening of the N-Cl bonds is suspected in the water-free compounds, which may contribute to the known thermal instability of the dehydrated salts of N-chloroarenesulfonamides. Various sections of IR spectra as well as X-ray powder diffraction patterns have proved to be suitable to identify the water-free and hydrated samples. 相似文献
19.
目的测定板蓝根颗粒抗流感病毒的药效作用。方法 A/California/7/2009(CA7)病毒滴鼻感染BALB/c小鼠观察14d,观察板蓝根对甲型H1N1流感病毒感染小鼠的保护作用,计算小鼠存活率、存活天数以及延长生命率。感染的小鼠第5天每组小鼠处死一半,取肺组织,观察板蓝根对甲型H1N1流感病毒感染小鼠肺组织的保护作用。结果板蓝根可明显延长甲型H1N1流感病毒感染小鼠的存活天数并提高存活率,病理结果显示板蓝根对甲型H1N1流感病毒感染的小鼠的肺组织有一定程度的保护作用,与模型组比较差异显著(P〈0.05)。结论板蓝根颗粒对甲型H1N1流感病毒感染的小鼠有较好的保护作用。 相似文献