The effects of amrinone on cardiac contraction and relaxation were assessed in isolated, perfused rat hearts. It was found that the left ventricular developed pressure (LVDP), dp/dtmax and -da/dtmax did not significan...The effects of amrinone on cardiac contraction and relaxation were assessed in isolated, perfused rat hearts. It was found that the left ventricular developed pressure (LVDP), dp/dtmax and -da/dtmax did not significantly increase . and the time constant (τ) did not markedly shorten with perfusion of low concentration ( 1 nmol/L , 100 nmol/L) of amrinone. The perfusion with higher concentration (1000 nmol/L) of amrinone reduced LVDP (P<0. 01 ) ,dp/dtmax (P<0.01) , -dp/dtmax (P<0. 01). and prolonged τ(P< 0. 05) significaiatly. It was assumed that amrinone has no direct positive inotropic effect. and can not improve cardiac relaxation. On the contrary, the cardiac contraction and relax ation will be inhibited at higher concentration of amrinone.展开更多
The role of the Ca^(2+)-permeable ion channel TRPC5 in regulating vasocontraction in obesity is poorly understood.Here,we investigated whether TRPC5 contributes to vascular dysfunction in obesity by promoting endothel...The role of the Ca^(2+)-permeable ion channel TRPC5 in regulating vasocontraction in obesity is poorly understood.Here,we investigated whether TRPC5 contributes to vascular dysfunction in obesity by promoting endothelium-dependent contraction via activation of cytosolic phospholipase A2(cPLA_(2))in the aortic endothelial cells of obese mice.Acetylcholine-induced endothelium-dependent relaxation and contraction in the aorta were measured us-ing wire myography.PLA_(2)activity was measured by the fluorogenic PLA_(2)substrate Bis-BODIPY^(TM)FL C_(11)-PC.The intracellular Ca^(2+)level in response to acetylcholine was measured by Fluo-4 fluorescence.Endothelium-derived contracting factors were assessed by enzyme immunoassay.Diet-induced obesity(DIO)attenuated endothelium-dependent vasodilation,enhanced endothelium-dependent contraction(EDC),and increased the expression of TRPC5 in the mouse aorta.Activation of TRPC5 promoted EDC in the wild-type mouse aorta,whereas pharma-cological inhibition and genetic knockout of TRPC5 decreased EDC in the DIO mouse aorta.Moreover,cPLA_(2)phosphorylation and activity were higher in aortic endothelial cells from DIO mice,and this was attenuated by inhibition and knockout of TRPC5.Cyclooxygenase 2(COX-2)expression was increased in DIO mouse endothe-lium and was decreased by a TRPC5 inhibitor and knockout of TRPC5.Release of prostaglandins F_(2α(PGF_(2α)and E 2(PGE 2)was involved in TRPC5-regulated EDC in DIO mice.This study demonstrated that TRPC5 contributes to endothelial and vascular dysfunction and is involved in EDC through activation of cPLA_(2)and enhanced COX-2-PGF_(2α)/PGE_(2)levels in DIO mice.展开更多
柔性互联装置的广泛应用给主动配电网(active distribution network,ADN)规划带来巨大挑战。该文提出一种考虑智能软开关(soft open point,SOP)接入的ADN扩展规划方法,对变电站新建及扩容,线路新建,智能软开关、分布式电源、储能系统以...柔性互联装置的广泛应用给主动配电网(active distribution network,ADN)规划带来巨大挑战。该文提出一种考虑智能软开关(soft open point,SOP)接入的ADN扩展规划方法,对变电站新建及扩容,线路新建,智能软开关、分布式电源、储能系统以及无功补偿等设备的选址定容进行协同规划。首先,考虑分布式电源出力和负荷功率不确定性,采用基于改进高斯混合模型的聚类方法构建典型日场景。在此基础上,以年综合费用最小为目标函数,建立了考虑SOP接入的ADN扩展规划模型。然后,通过线性化和二阶锥松弛技术,将原始非凸非线性规划模型转化为混合整数二阶锥规划(mixed-integer second-order cone programming,MISOCP)模型,并提出逐次收缩凸松弛算法以获得凸松弛间隙足够小的原问题最优解。最后,在54节点主动配电网算例上验证了所提规划模型和求解算法的可行性与有效性。展开更多
目的研究不同周龄对大鼠心肌细胞收缩／舒张功能的影响。方法SD大鼠分为三个周龄组：A组（12～15周）、B组（36～41周）和C组（51～55周），并以常规酶解法分离成年大鼠心肌细胞，观察分离即刻（D时间点）、复钙1h后（E时间点）和电刺激...目的研究不同周龄对大鼠心肌细胞收缩／舒张功能的影响。方法SD大鼠分为三个周龄组：A组（12～15周）、B组（36～41周）和C组（51～55周），并以常规酶解法分离成年大鼠心肌细胞，观察分离即刻（D时间点）、复钙1h后（E时间点）和电刺激10min后（F时间点）心肌细胞成活率，采用IonOptix单细胞动缘探测系统同步检测心肌细胞的收缩幅度、收缩／舒张速度和钙瞬变等，这些指标均由计算机自动实时采集并记录。结果复钙1h后和电刺激10min后心肌细胞成活率降低均有统计学意义（P〈0．05或P〈0．01），周龄越大越明显，随着周龄的增大，心肌细胞收缩幅度（峰值高度，ph）、心肌细胞收缩幅度／单个心肌细胞的长度百分比（ph／bl％）、最大收缩速率（maximal velocity of contraction，＋dL／dt）、最大舒张速率（maximal velocity of relaxation，-dL／dt）和钙瞬变幅度（⊿FFI）降低，ph在A组、B组和C组分别为（0．14±0．06），（0．12±0．05），（0．11±0．05）／zmph／b1％分别为（9．17±3．54）％、（7．14±2．58）％和（6．56±2．36）％；＋dL／dt分别为（2．01±0．74），（1．82±0．51），（1．51±0．56）μm／s；-dL／dt分别为（2．10±0．75），（1．70±0．62），（1．41±0．52）μm／s；⊿FFI分别为（0．38±0．05），（0．35±0．04），（0．25±0．05）。其中C组ph／bl%、＋dL／dt、-dL／dt和么FFI均较A组显著降低（P〈0．05），降低幅度分别为27％，26％，33％和31％。结论随着周龄的增大，分离大鼠心肌细胞的成活率下降，大鼠心肌细胞的收缩／舒张功能降低，钙瞬变幅度减小。展开更多
文摘The effects of amrinone on cardiac contraction and relaxation were assessed in isolated, perfused rat hearts. It was found that the left ventricular developed pressure (LVDP), dp/dtmax and -da/dtmax did not significantly increase . and the time constant (τ) did not markedly shorten with perfusion of low concentration ( 1 nmol/L , 100 nmol/L) of amrinone. The perfusion with higher concentration (1000 nmol/L) of amrinone reduced LVDP (P<0. 01 ) ,dp/dtmax (P<0.01) , -dp/dtmax (P<0. 01). and prolonged τ(P< 0. 05) significaiatly. It was assumed that amrinone has no direct positive inotropic effect. and can not improve cardiac relaxation. On the contrary, the cardiac contraction and relax ation will be inhibited at higher concentration of amrinone.
基金This work was supported by the National Natural Science Foundation of China(Grants No.81622007,81960662,and 82000291)the Chang Jiang Scholars Program(Grant No.Q2015106)+3 种基金Fundamental Research Funds for the Central Universities(Grant No.JUSRP51704A)the National First-class Discipline Program of Food Science and Technology(Grant No.JUFSTR20180101)Fundamental Research Funds for Young Scholars of Jiangnan University(Grant No.JUSRP12046)the Natural Science Foundation for Young Scholars of Jiangsu Province(Grant No.BK20190596).
文摘The role of the Ca^(2+)-permeable ion channel TRPC5 in regulating vasocontraction in obesity is poorly understood.Here,we investigated whether TRPC5 contributes to vascular dysfunction in obesity by promoting endothelium-dependent contraction via activation of cytosolic phospholipase A2(cPLA_(2))in the aortic endothelial cells of obese mice.Acetylcholine-induced endothelium-dependent relaxation and contraction in the aorta were measured us-ing wire myography.PLA_(2)activity was measured by the fluorogenic PLA_(2)substrate Bis-BODIPY^(TM)FL C_(11)-PC.The intracellular Ca^(2+)level in response to acetylcholine was measured by Fluo-4 fluorescence.Endothelium-derived contracting factors were assessed by enzyme immunoassay.Diet-induced obesity(DIO)attenuated endothelium-dependent vasodilation,enhanced endothelium-dependent contraction(EDC),and increased the expression of TRPC5 in the mouse aorta.Activation of TRPC5 promoted EDC in the wild-type mouse aorta,whereas pharma-cological inhibition and genetic knockout of TRPC5 decreased EDC in the DIO mouse aorta.Moreover,cPLA_(2)phosphorylation and activity were higher in aortic endothelial cells from DIO mice,and this was attenuated by inhibition and knockout of TRPC5.Cyclooxygenase 2(COX-2)expression was increased in DIO mouse endothe-lium and was decreased by a TRPC5 inhibitor and knockout of TRPC5.Release of prostaglandins F_(2α(PGF_(2α)and E 2(PGE 2)was involved in TRPC5-regulated EDC in DIO mice.This study demonstrated that TRPC5 contributes to endothelial and vascular dysfunction and is involved in EDC through activation of cPLA_(2)and enhanced COX-2-PGF_(2α)/PGE_(2)levels in DIO mice.
文摘柔性互联装置的广泛应用给主动配电网(active distribution network,ADN)规划带来巨大挑战。该文提出一种考虑智能软开关(soft open point,SOP)接入的ADN扩展规划方法,对变电站新建及扩容,线路新建,智能软开关、分布式电源、储能系统以及无功补偿等设备的选址定容进行协同规划。首先,考虑分布式电源出力和负荷功率不确定性,采用基于改进高斯混合模型的聚类方法构建典型日场景。在此基础上,以年综合费用最小为目标函数,建立了考虑SOP接入的ADN扩展规划模型。然后,通过线性化和二阶锥松弛技术,将原始非凸非线性规划模型转化为混合整数二阶锥规划(mixed-integer second-order cone programming,MISOCP)模型,并提出逐次收缩凸松弛算法以获得凸松弛间隙足够小的原问题最优解。最后,在54节点主动配电网算例上验证了所提规划模型和求解算法的可行性与有效性。
文摘目的研究不同周龄对大鼠心肌细胞收缩／舒张功能的影响。方法SD大鼠分为三个周龄组：A组（12～15周）、B组（36～41周）和C组（51～55周），并以常规酶解法分离成年大鼠心肌细胞，观察分离即刻（D时间点）、复钙1h后（E时间点）和电刺激10min后（F时间点）心肌细胞成活率，采用IonOptix单细胞动缘探测系统同步检测心肌细胞的收缩幅度、收缩／舒张速度和钙瞬变等，这些指标均由计算机自动实时采集并记录。结果复钙1h后和电刺激10min后心肌细胞成活率降低均有统计学意义（P〈0．05或P〈0．01），周龄越大越明显，随着周龄的增大，心肌细胞收缩幅度（峰值高度，ph）、心肌细胞收缩幅度／单个心肌细胞的长度百分比（ph／bl％）、最大收缩速率（maximal velocity of contraction，＋dL／dt）、最大舒张速率（maximal velocity of relaxation，-dL／dt）和钙瞬变幅度（⊿FFI）降低，ph在A组、B组和C组分别为（0．14±0．06），（0．12±0．05），（0．11±0．05）／zmph／b1％分别为（9．17±3．54）％、（7．14±2．58）％和（6．56±2．36）％；＋dL／dt分别为（2．01±0．74），（1．82±0．51），（1．51±0．56）μm／s；-dL／dt分别为（2．10±0．75），（1．70±0．62），（1．41±0．52）μm／s；⊿FFI分别为（0．38±0．05），（0．35±0．04），（0．25±0．05）。其中C组ph／bl%、＋dL／dt、-dL／dt和么FFI均较A组显著降低（P〈0．05），降低幅度分别为27％，26％，33％和31％。结论随着周龄的增大，分离大鼠心肌细胞的成活率下降，大鼠心肌细胞的收缩／舒张功能降低，钙瞬变幅度减小。
