Effects of Ca^(2+) channel blockers on store-operated Ca^(2+) channel currents of Kupffer cells after hepatic ischemia/reperfusion injury in rats

AIM： To study the effects of hepatic ischemia/ reperfusion （I/R） injury on store-operated calcium channel （SOC） currents （Isoc） in freshly isolated rat Kupffer cells, and the effects of Ca^2＋ channel blockers, 2-aminoethoxydiphenyl borate （2-APB）, SK＆F96365, econazole and miconazole, on Isoc in isolated rat Kupffer cells after hepatic I/R injury.METHODS： The model of rat hepatic I/R injury was established. Whole-cell patch-clamp techniques were performed to investigate the effects of 2-APB, SK＆F96365, econazole and miconazole on Isoc in isolated rat Kupffer cells after hepatic I/R injury.RESULTS： I/R injury significantly increased Isoc from -80.4±25.2pA to -159.5±34.5pA （^bp 〈 0.01, n = 30）. 2-APB （20, 40, 60, 80, 100 pmol/L）, SK＆F96365 （5, 10, 20, 40, 50 pmol/L）, econazole （0.1, 0.3, 1, 3, 10 μmol/L） and miconazole （0.1, 0.3, 1, 3, 10 μmol/L） inhibited Isoc in a concentration-dependent manner with IC50 of 37.41 μmol/L （n = 8）, 5.89 μmol/L （n = 11）, 0.21 μmol/L （n = 13）, and 0.28 μmol/L （n = 10）. The peak value of Isoc in the I-V relationship was decreased by the blockers in different concentrations, but the reverse potential of Isoc was not transformed. CONCLUSION： SOC is the main channel for the influx of Ca^2＋ during hepatic I/R injuries. Calcium channel blockers, 2-APB, SK＆F96365, econazole and miconazole,have obviously protective effects on I/R injury, probably by inhibiting Isoc in Kupffer cells and preventing the activation of Kupffer cells.

Effects of Atractylodes Macrocephala on the Cytomembrane Ca^(2+)-activated K^+ Currents in Cells of Human Pregnant Myometrial Smooth Muscles

The study examined the inhibitory effect of Atractylodes macrocephala （AM） on the uterine contraction during premature delivery and explored its electrophysiological mechanism by studying the effects of AM on the Ca^2＋-activated K^＋ currents of pregnant human myometrial smooth muscle cells with or without the treatment with intedeukin-6. Single cells were acutely isolated from pregnant human myometrial smooth muscles. Whole-cell Ca^2＋-activated K^＋ currents were recorded by using an Axopatchl-D amplifier. The cells were divided into three groups： group A in which AM was added into perfusate, group B, in which interleukin-6 was added into perfusate） and group C in which AM was added into perfusate after addition of interleukin-6. IL-6 10 ng/mL inhibited BKca by 36.9%±13.7% as compared with control （P〈0.01）. AM at 2 mg/mL raised BKca by 36.7%±22.6% or 45.2%±13.7% with or without the treatment of IL-6, respectively （P〈0.01）. It is concluded that AM was able to enhance the BKca of pregnant human myometrial smooth muscle cells treated or untreated with interleukin-6 and its effect on the BKca IL-treated cells was stronger that its effect on BKca of untreated cells. Our results suggested that AM can help to maintain the membrane potentials and the resting status of pregnant human myometrial smooth muscle cells.

水溶液环境下手性配合物Phe·Ca^(2+)对映异构机理的DFT研究

采用DFT(density functional theory)的M06-2X、MN15方法和处理溶剂效应的SMD模型方法,研究了水溶液中S-苯丙氨酸(S-Phe)与二价钙(Ca^(2+))配合物(Phe·Ca^(2+))的对映异构。反应通道研究发现,S-Phe·Ca^(2+)的对映异构可在质子以N和O分别为桥以及O和N联合为桥迁移的3个通道上实现。计算表明:最优势通道是质子以N为桥迁移,隐性水溶剂效应下决速步自由能垒是227.5 kJ/mol,显性水溶剂效应下该能垒降至108.0~117.6 kJ/mol。结果表明:水溶液中手性Phe·Ca^(2+)的消旋过程十分缓慢,将其用于生命体同补苯丙氨酸和钙元素可能比较安全。

Effects of Arecoline on Calcium Channel Currents and Caffeine-induced Calcium Release in Isolated Single Ventricular

The effects of Arecoline (Are) on calcium m obilization were investigated. In isolated single ventricular m yocyte of guinea pig,patch clamp whole cell recording techniques were used to record the current of L - type calcium channel and cytosolic Ca2 + level ([Ca2 + ]i) labeled with fluo- rescence probe Fluo- 3/ AM was m easured under a laser scanning confocal microscope.Results re- vealed that Are(3- 10 0 μm ol/ L) could inhibit L- type calcium current in a concentration- depen- dent manner and the value of IC50 was33.73μm ol/ L (n=5 ) .In the absence of extracellular calci- um,the resting levels of[Ca2 + ]i was not affected by Are(n=6 ,P>0 .0 5 ) ,but pretreatment with Are(30 μmol/ L) could significantly inhibit the[Ca2 + ]i elevation induced by caffeine(10 m mol/ L,n=6 ,P<0 .0 1) .It was concluded that Are could inhibit not only calcium influx through L- type calcium channel but also calcium release from sarcoplasm ic reticulum.

粒度和温度对纳米Ca(OH)_(2)溶解行为的影响

以微米级到纳米级的Ca(OH)_(2)粉末作为原料,采用pH玻璃电极的测试方法分析粉末粒度和溶解温度对Ca(OH)_(2)溶解过程的影响。研究表明:溶解过程在表面反应控制条件下,拟合得到的表观溶解速率常数随着粒度的减小而增大,当溶解温度由25℃增加到55℃、平均粒度由3.81μm降低到56.47 nm时,Ca(OH)_(2)的表观溶解速率常数从6.17×10^(-4)mol/(L·s)增加到了2.01×10^(-3)mol/(L·s),Ca(OH)_(2)的表观溶解反应级数为1.78;当温度分别为25℃、35℃、45℃、55℃时,粒度与表观溶解速率常数呈函数关系。利用Arrhenius方程回归获得平均粒度为3.81μm、0.82μm、78.90 nm、56.47 nm的Ca(OH)_(2)粉末在25~55℃条件下的表观溶解活化能分别为31.99 kJ/mol、31.73 kJ/mol、27.55 kJ/mol、17.80 kJ/mol。纳米Ca(OH)_(2)溶解能够在更短的时间达到较高的pH值,有提高根管消毒效率的可能。

Effects of fructose-1,6-diphosphate on concentration of calcium and activities of sarcoplosnic Ca^(2+)-ATPase in cardiomyocytes of Adriamycin-treated rats

Objective: To observe the effects of fructose-1,6-diphosphate (FDP) on serum levels of cardiac troponin 1 (cTnl) and creatine kinase-MB (CK-MB), as well as the concentration of calcium in cardiomyocytes (Myo[Ca2+]) and activity of sarcoplosnic Ca2+-ATPase (SRCa2+-ATPase) in Adriamycin (ADR)-treated rats. Methods: Rats were intraperitoneally injected with ADR (2.5 mg/kg every other day for 6 times) and then with different dosages of FDP (every other day for twenty-one times). Bi-antibodies sandwich Enzyme linked immune absorption assay (ELISA) was performed to detect serum level of cTnl. CK-MB was detected by monoclonal antibody, Myo[Ca2+] was detected by fluorescent spectrophotometry and the activity of SRCa2+-ATPase was detected by inorganic phosphate method. Results: FDP (300, 600, 1200 mg/kg) significantly reduced the serum levels of cTnl and CK-MB, while at the same time decreased calcium concentration and increased SRCa2+-ATPase activity in cardiomyocytes of ADR-treated rats (P<0.01). Conclusions: FDP might alleviate the cardiotoxic effects induced by ADR through decreasing calcium level as well as increasing SRCa2+-ATPase activity in cardiomyocytes.

苹果sMdCAX11基因的功能分析与鉴定

【目的】深入分析苹果sMdCAX11(去掉NRR区域的MdCAX11)基因功能。【方法】分别利用蜜脆苹果果实和拟南芥材料,采用过表达sMdCAX11的试验方法,观察果实、叶片等各组织的表型,并测定不同组织的矿质元素含量,同时对苹果MdCAX11基因启动子区域进行预测分析以及启动子转录活性分析。【结果】瞬时过表达sMdCAX11的苹果果肉颜色变褐,并出现皱缩;同时过表达sMdCAX11的苹果果肉和拟南芥叶片的总Ca含量明显下降,且元素比值(K+Mg)/Ca明显升高。【结论】sMdCAX11基因过表达可导致植株组织的元素分配不均,不同元素间的比例失衡。

Simultaneous CO_(2) capture and thermochemical heat storage by modified carbide slag in coupled calcium looping and CaO/Ca(OH)2 cycles

The simultaneous CO_(2) capture and heat storage performances of the modified carbide slag with byproduct of biodiesel were investigated in the process coupled calcium looping and CaO/Ca(OH)2 thermochemical heat storage using air as the heat transfer fluid.The modified carbide slag with by-product of biodiesel exhibits superior CO_(2) capture and heat storage capacities in the coupled calcium looping and heat storage cycles.The hydration conversion and heat storage density of the modified carbide slag after 30 heat storage cycles are 0.65 mol·mol^(-1) and 1.14 GJ·t^(-1),respectively,which are 1.6 times as high as those of calcined carbide slag.The negative effect of CO_(2) in air as the heat storage fluid on the heat storage capacity of the modified carbide slag is overcome by introducing CO_(2) capture cycles.In addition,the CO_(2) capture reactivity of the modified carbide slag after the multiple calcium looping cycles is enhanced by the introduction of heat storage cycles.By introducing 10 heat storage cycles after the 10th and 15th CO_(2) capture cycles,the CO_(2) capture capacities of the modified carbide slag are subsequently improved by 32%and 43%,respectively.The porous and loose structure of modified carbide slag reduces the diffusion resistances of CO_(2) and steam in the material in the coupled process.The formed CaCO_(3)in the modified carbide slag as a result of air as the heat transfer fluid in heat storage cycles decomposes to regenerate CaO in calcium looping cycles,which improves heat storage capacity.Therefore,the modified carbide slag with by-product of biodiesel seems promising in the coupled calcium looping and CaO/Ca(OH)_(2) heat storage cycles.

不同补钙方式对固定献血者血清Ca^(2+)及PTH的影响分析

目的探讨不服钙剂、口服葡萄糖酸钙、口服乳酸钙颗粒三种情况对于固定单采血小板献血者血清钙(Ca^(2+))、血清甲状旁腺素(PTH)和献血不良反应的影响,比较哪种钙剂的效果更好。方法2020年7月—9月从本中心固定献血者人群中招募35名志愿者(男性21名,女性14名)共同参与三组实验:第一组实验为对照组,即在单采血小板前不予补充钙剂;第二组在采前20 min(采样后)补充10%葡萄糖酸钙口服液;第三组在采前20 min(采样后)补充乳酸钙颗粒。三组实验中,每一组都分别在采样时(采前20 min)、穿刺时(采集0 min)、采集初中期(采集20 min)、采集中后期(采集40 min)留取全血标本5 mL用于血清Ca^(2+)和血清PTH的检测。比较三组血清Ca^(2+)和血清PTH数值的变化趋势,探讨钙剂的作用效果。结果献血者血清Ca^(2+)随时间的改变在显著变化(F=101.979,P<0.001),组间效应不显著(F=0.059,P=0.943>0.05);血清PTH随时间的改变在显著变化(F=495.834,P<0.001),组间效应不显著(F=1.241,P=0.294>0.05);血清Ca^(2+)和血清PTH数值随采血时间的变化成负相关。两种钙剂均能减少枸橼酸盐反应的发生概率(P<0.001)。结论无论是否预防性补充钙剂,或是补充何种钙剂,献血者体内血清Ca^(2+)均能够在PTH的作用下保持稳定;预防性补充钙剂可以降低枸橼酸盐反应发生率。

Degradation of critical current in Bi2212 composite wire under compression load

Since Bi2Sr2Ca1Cu2O8＋x（Bi2212） wires are subject to mechanical loadings, degradation of critical current will occur. The effect of compressive loadings on the critical current of Bi2212 wire is studied by considering micro-buckling of filament. A Bi2212 wire is regarded as a unidirectional filament-reinforced composite in the theoretical analysis. By considering the influence of inclusion, the micro-buckling wavelength can be derived by using a two-dimensional model. Based on the experimental results, the critical current is fitted as a function of buckling wavelength. It is found that the decrease of the critical current is directly proportional to the reciprocal of square of the buckling wavelength. Change of micro-buckling wavelength with material parameters is discussed. A critical strain in the wire with a filament bridge is analyzed using the finite element method.

EFFECTS OF THE HOE 694 ON TRANSIENT INWARD CURRENT AND NA^+- CA^(2+) EXCHANGE IN GUINEA PIG CARDIOMYOCYTES

To determine the effects of HOE 694, a new and potent Na＋- H＋ exchanger blocker, on transient inward current (Iti) and Na＋- Ca2＋ exchange during hypoxia- reoxygenation in guinea pig cardiomyocytes. Methods. Cardiomyocytes were isolated from adult guinea pig ventricle. Experiment was performed in an experimental chamber that allowed the cells to be exposed to a sufficiently low O2 pressure. The cells were subjected to hypoxia and reoxygenation. The ionic currents were studied with patch clamp technique. Results. In the absence of HOE 694, hypoxia- reoxygenation induced Iti in 12 of 15 experiments; but in cardiomyocytes pretreated with HOE 694 (10～ 50μ mol/L), the incidence of Iti observed during reoxygenation was reduced to 5 of 11 experiments and 3 of 10 experiments, P Conclusions. Blockade of the Na＋- H＋ exchange by HOE 694 could reduce Ca2＋ overload upon hypoxia- reoxygenation, and inhibition of Na＋- H＋ exchange may also indirectly decrease Na＋- Ca2＋ exchange activity during hypoxia.

镉对玉米苗中钙调蛋白含量和Ca^(2+)-ATPase活性的影响

试验采用营养液培养的方法,以玉米为试材,研究了不同供镉浓度(0、52、0和100μmol/L)和处理时间(122、4、48、96、168 h)对植株体内钙调蛋白(CaM)含量及生物膜上的Ca2+-ATPase活性的影响。结果表明,植株可溶性Ca2+含量在镉胁迫后较不加镉处理增加,镉处理在叶和根中分别在48和24 h后达最高,然后随镉处理浓度和处理时间的增加逐步下降;同时镉诱导了植株CaM的合成,其含量随镉处理浓度和处理时间增加逐步增加,但20μmol/L和100μmol/L镉处理在168 h后有所下降;与不加镉处理相比,镉胁迫导致植株生物膜上的Ca2+-ATPase活性迅速升高,但随镉处理浓度提高和时间延长,镉胁迫植株的Ca2+-ATPase活性在48 h(质膜、液泡膜和内质网膜)和24 h(线粒体膜)后逐步降低。各膜上的Ca2+-ATPase活性依次为质膜>液泡膜>内质网膜>线粒体膜,且同一微囊膜,根中的活性大于叶中。

海嘧啶对肿瘤细胞内[Ca^(2+)]_i的影响

研究表明海嘧啶抗癌疗效确切 ,抗癌机制与其诱导肿瘤细胞凋亡有关 .旨在进一步揭示海嘧啶诱导肿瘤细胞凋亡的机制 ,采用激光扫描共聚焦技术观察海嘧啶对肿瘤细胞内 [Ca2 +]i 的影响及 [Ca2 +]i 变化时Ca2 +的来源 ,采用定磷法测定海嘧啶对肿瘤细胞膜钙泵活性的影响 .海嘧啶可显著升高肿瘤细胞内[Ca2 +]i 的浓度 ;[Ca2 +]i 升高时 ,Ca2 +同时来源于细胞外钙内流和细胞内钙释放 .海嘧啶可显著降低肿瘤细胞膜钙泵活性 .海嘧啶通过升高肿瘤细胞内 [Ca2 +]i 的浓度 ,从而启动肿瘤细胞凋亡机制 ,诱导肿瘤细胞凋亡 ;海嘧啶升高肿瘤细胞内的作用是通过开放肿瘤细胞膜钙通道、引起肿瘤细胞内钙库释放、降低肿瘤细胞钙泵活性三条途径达到的 .

NO可能作为Ca^(2+)的下游信号介导乙烯诱导的蚕豆气孔关闭

以蚕豆(Vicia fabaL.)为材料,利用药理学实验,结合激光共聚焦显微技术和分光光度法,探讨Ca2+和一氧化氮(nitric oxide,NO)在乙烯(ethylene,Eth)调控气孔运动信号转导中的作用。结果表明,光下乙烯利(0.004%,0.04%,0.4%)可诱导蚕豆叶片气孔关闭,且具有时间和剂量效应;NO清除剂cPTIO、硝酸还原酶(nitrate reductase,NR)抑制剂NaN3及胞外Ca2+螯合剂EGTA可部分逆转乙烯诱导的气孔关闭;乙烯能够明显增加气孔保卫细胞NO水平;提高蚕豆叶片NO含量和NR活性,并且NO的含量变化与NR活性的变化趋势基本一致;NR抑制剂NaN3可抑制乙烯诱导的气孔保卫细胞和叶片NO含量的增加;清除胞外Ca2+可减弱乙烯对NO含量和NR活性的诱导效应。说明Ca2+和NO均参与乙烯诱导的蚕豆气孔关闭,且NO(主要由NR途径合成)可能位于Ca2+下游参与调控这一信号转导过程。

广枣总黄酮对大鼠心室肌细胞IC_a、I_(to)和细胞[Ca^(2+)]_i的影响

目的 观察广枣总黄酮对大鼠心室肌细胞L 型钙通道电流 (ICa)和瞬时外向钾通道电流 (Ito)以及对心肌细胞内游离钙浓度 ([Ca2 + ]i)的影响 ,探讨其抗心律失常作用机制。方法 全细胞膜片钳记录大鼠心室肌细胞ICa、Ito,激光共聚焦显微镜观察细胞 [Ca2 + ]i 的变化。结果 在钳制电压- 4 0mV ,实验电压 - 4 0～ +5 0mV时 ,广枣总黄酮 10 0mg·L-1对心室肌细胞ICa无显著影响 ;在钳制电压 - 6 0mV ,实验电压 - 4 0～ +5 0mV时显著抑制瞬时外向钾通道Ito(P <0 0 5 ) ;而激光共聚焦显微镜结果显示广枣总黄酮在 5 0、10 0、2 0 0mg·L-1却降低缺氧复氧心肌细胞收缩期和静息期[Ca2 + ]i 的浓度。结论 广枣总黄酮对心肌细胞ICa无显著影响 ,可显著抑制瞬时外向钾通道Ito,并可明显降低心肌细胞收缩期和静息期细胞 [Ca2 + ]i 浓度。这可能是其抗心律失常和保护缺血心肌的主要作用机制。

赤芍对高脂兔血小板胞浆游离钙、红细胞膜Ca^（2＋）－Mg^（2＋）－ATP酶活性的影响

本研究观察了赤芍对高脂兔血小板胞浆游离钙（［Ｃａ２＋］ｉ）、红细胞膜钙－镁－ＡＴＰ酶（Ｃａ２＋－Ｍｇ２＋－ＡＴＰａｓｅ）活性血清钙及血脂的影响。结果表明：血小板［Ｃａ２＋］ｉ含量赤芍组（２７６．２５±２７．００ｎｍｏｌ／Ｌ）显著低于高脂组（３９０．８８±７０．００ｎｍｏｌ／Ｌ），Ｐ＜０．０１；红细胞膜Ｃａ２＋－Ｍｇ２＋－ＡＴＰａｓｅ基础及激活活性（μｍｏｌ·ｐｉ－１·ｍｇ－１·ｈ－１）赤芍组（０．７９±０．０５，１．３４±０．１０）明显高于高脂组（０．６５±０．０９，１．０４±０．１３），Ｐ＜０．０１。说明赤芍可提高高脂血症兔红细胞Ｃａ２＋－Ｍｇ２＋－ＡＴＰ酶基础及激活活性。

胞外Ca^(2+)信号——动植物中的第一信使

钙离子作为重要的胞内第二信使,控制着许多细胞的功能,人们对此已经研究得比较深入。然而最近发现的一些细胞表面胞外Ca2+探测器使我们想到是否在胞外环境中,钙离子也具有信号分子的功能。钙离子传感器包括已经研究得比较清楚的胞外Ca2+敏感受体—最初从甲状旁腺分离的G-耦联蛋白受体(CaR),另外,还有其他受体、通道和膜蛋白也都对胞外[Ca2+]的变化很敏感。最近从拟南芥保卫细胞中克隆到一个胞外钙离子受体蛋白(CAS),通过胞外钙离子的变化引起胞内钙离子信号。这些受体蛋白的克隆,使人们确信Ca2+在细胞中可以发挥第一信使的功能。

异丙肾上腺素致大鼠心肌肥大时心肌细胞核Ca^(2+)转运功能异常

为观察异丙肾上腺素致大鼠心肌肥大时心肌细胞核Ca2+转运功能的改变，给大鼠皮下注射异丙肾上腺素制各心肌肥大模型，采用差速离心和密度梯度离心法分离纯化心肌细胞核，并用酶学方法鉴定核的纯度及测定ATP酶活性，用45Ca2+同位素法测定核钙摄取。结果发现，与对照组相比，实验组肥大心脏的心系数增加40％（P＜0．01），心肌胶原含量增加81％（P＜0．01），Ca2+含量增加41％（P＜0．05），心脏组织呈显著的肥大和纤维化表现。实验组心肌细胞核Ca2+依赖性ATP酶的Ca2+浓度最大反应速度较对照组降低35％（P＜0．01），平衡常数降低46％（P＜0．05），对ATP浓度反应无显著改变，45Ca2+摄取显著低于对照组（P<0.01），其最大反应速度与对照组相比降低62％（P＜0.01），而平衡常数无显著变化。提示异丙肾上腺素所致大鼠的肥大心肌细胞核钙转运功能降低。

高压氧对脑缺血及再灌注时海马游离Ca^（2＋）及钙通道的作用

应用新型钙离子荧光指示剂Ｆｕｒａ－２／ＡＭ测定海马突触体内游离Ｃａ￣（２＋）浓度，观察在脑缺血时及不同压力高压氧治疗后的变化规律，并应用［￣３Ｈ］ＰＮ２００－１１０作为放射性配基，用放射配体结合法测定海马组织Ｌ－型钙通道生物学特性和缺血及高压氧治疗后的变化。结果表明：脑缺血及再灌注后海马脑区突触体内游离Ｃａ￣（２＋）浓度显著增加，其Ｌ－型钙通道的Ｂｍａｘ和Ｋｄ值均显著上升，但经吸入高压氧后，可降低胞浆内游离Ｃａ￣（２＋）浓度，其中以２５３．２５ｋＰａ高压氧作用明显，并可降低钙通道的Ｂｍａｘ与Ｋｄ值。说明高压氧部分地通过减少细胞内游离Ｃａ￣（２＋）而起作用，Ｌ－型钙通道参与了高压氧降低脑缺血后胞浆内游离Ｃａ￣（２＋）浓度的作用，高压氧可使其开放的通道数量减少。

海嘧啶对肿瘤细胞内[Ca^(2+)]_i的影响

目的 揭示海嘧啶诱导肿瘤细胞凋亡的机制。方法 采用激光扫描共聚焦技术观察海嘧啶对肿瘤细胞内[Ca2 +]i 的影响及 [Ca2 +]i 变化时 Ca2 +的来源 ,采用定磷法测定海嘧啶对肿瘤细胞膜钙泵活性的影响。结果 海嘧啶可显著升高肿瘤细胞内 [Ca2 +]i 的浓度 ,[Ca2 +]i 升高时 ,Ca2 +同时来源于细胞外钙内流和细胞内钙释放。海嘧啶可显著降低肿瘤细胞膜钙泵活性。结论 海嘧啶通过升高肿瘤细胞内 [Ca2 +]i 的浓度 ,从而启动肿瘤细胞凋亡机制 ,诱导肿瘤细胞凋亡 ;海嘧啶升高肿瘤细胞内的作用是通过开放肿瘤细胞膜钙通道、引起肿瘤细胞内钙库释放、降低肿瘤细胞钙泵活性 3条途径达到的。