特布他林对海水浸泡人肺泡上皮细胞钠钾泵及钠通道的影响

目的 探讨特布他林对海水浸泡的人肺泡上皮细胞(A549)钠水转运通道的影响.方法 将常规培养的A549细胞分为海水处理(SG)组、特布他林(20 μmol/L孵育6h)处理(TG)组和阴性对照(NG)组.采用甲基噻唑基四唑(MTT)法检测细胞存活率,流式细胞仪检测细胞的凋亡和坏死情况,Western blotting法检测钠钾泵α1亚单位(Na+/K+-adenosine triphosphatase-α1,NKA-α1)、钠通道α亚单位(epithelail sodium channds-α,α-ENaC)的表达,水解比色法检测Na+-K+-ATP酶(Na-/K+-exchanging ATPase,NKA)活性.结果 MTT法及流式细胞仪检测结果均显示,特布他林处理对海水孵育后细胞的存活率无影响.NG组的NKA-α1和α-ENaC蛋白表达显著高于SG组(P＜0.01)和TG组(t=3.71,3.78,P＜0.01),TG组显著高于SG组(t=2.58,2.64;P＜0.05).与NG组NKA酶活性[(31.298±5.779)μmol/(mg·h)]比较,SG组[(14.211±3.885)μmol/(mg·h)]和TG组[(19.521±1.648)μmol/(mg·h)]明显降低(t=2.54,2.71;P＜0.05);TG组的NKA酶活性[(19.521±1.648)μmol/(mg·h)]较SG组升高(t=2.51,P＜0.05).结论 特布他林不影响人肺泡上皮细胞存活,并且可以抑制海水浸泡引起的α-ENaC、NKA-α1含量及NKA活性的下降.     

二至丸对自然衰老小鼠血液流变学及心肌能量代谢酶的影响

目的：研究长期给予二至丸对自然衰老小鼠血液流变学及心肌能量代谢的影响。方法：小鼠分为正常对照组和二至丸组,二至丸按1.8g.kg-1的剂量给予昆明种小鼠,并制备成含药饲料,自6月龄开始给药,至18月龄结束,测定其对血液流变学以及心肌组织Na＋-K＋-ATP酶、Ca2＋-Mg2＋-ATP酶、SDH、LDH活性的影响。结果：二至丸组会使红细胞聚集指数降低,但是与空白对照组比较没有统计学意义;二至丸组能提高SDH酶、LDH酶、Na＋K＋ATP酶、Ca2＋Mg2＋ATP酶的活性,与空白组比较具有显著的有统计学意义（P〈0.05）。结论：二至丸能够提高心肌有氧代谢能力,从而延缓机体衰老的进程。     

姜黄素对缺氧/复氧心肌细胞凋亡的影响及其机制的研究

目的研究姜黄素(Cur)对缺氧/复氧干预下心肌细胞凋亡的影响以及其可能的作用机制。方法用体外培养的SD乳大鼠心肌细胞,建立缺氧(4 h)/复氧(1 h)模型,然后用磷脂酰肌醇3-激酶(PI3-K)特异性的抑制剂LY294002进行干预。实验分为对照组、缺氧/复氧组(H/R)、H/R+Cur组和H/R+Cur+LY294002组。用MTT比色法测定细胞活力,Annexin-V与PI双染法及流式细胞仪检测心肌细胞凋亡率,Western blotting检测磷酸化Akt(p-Akt)和总Akt(t-Akt)蛋白水平的表达变化。结果与H/R组和H/R+Cur+LY294002组相比,H/R+Cur组能显著抑制缺氧/复氧损伤所诱导的细胞存活率的下降(P均<0.01),并且可显著降低心肌细胞的凋亡率(P均<0.05);同时H/R+Cur组Akt磷酸化明显增强(P均<0.01)。结论Cur可抑制缺氧/复氧损伤引起的心肌细胞凋亡,其抗细胞凋亡作用可能与Cur激活细胞内信号传递途径PI3-K/Akt有关。     

银杏内酯B对体外培养乳鼠心肌细胞氧化损伤的保护作用

目的探讨银杏内酯B对体外培养乳鼠心肌细胞氧化损伤的保护作用及其机制.方法利用低浓度过氧化氢诱导原代培养乳鼠心肌细胞氧化损伤为模型,通过电镜观察细胞超微结构,以及培养介质中LDH活力,MDA含量,心肌细胞内Na -K -ATPase,GSH-PX活力的改变,来评价银杏内酯B对心肌细胞的保护作用,并探讨其机制.结果过氧化氢对心肌细胞有显著的损伤作用.银杏内酯B可使培养介质中的LDH和MDA水平显著下降,细胞内Na -K -ATPase,GSH-PX活力显著提高,同时细胞超微结构得到改普.结论银杏内酯B对过氧化氢致心肌细胞损伤有保护作用,机理与其抑制脂质过氧化和提高细胞内钠钾泵活力的作用有关.     

大鼠脑内多巴胺受体超敏与Na^＋—K^＋—ATP酶活性变化的相关性研究

目的 研究超敏状态下多巴胺（ＤＡ）受体调节功能的变化与Ｎａ＾＋－Ｋ＾＋－ＡＴＰ酶活性活性变化的可能相关性。方法 采用慢性连续给予ＤＡ受体拮抗剂的方法导致大离内ＤＡ受体的超敏。应用分光光度法测定Ｎａ＾＋－Ｋ＾＋－ＡＴＰ酶经ＡＴＰ水解释放的无机磷而确定酶的活性。结果 生给予利血平、氯氮平和氟哌啶醇对大鼠纹状体、海马和皮层Ｎａ－Ｋ－ＡＴＰ酶的活性均无显著影响。而以相同剂量的利血平、氯氮平和氟哌啶醇连续给     

大鼠心肌缺血再灌注损伤对心肌细胞膜钠泵表达的影响

目的：观察心肌缺血再灌注（MIR）损伤大鼠心肌组织内洋地黄素水平、ATP酶活性、线粒体Ca^2＋浓度以及Na^＋-K^＋-ATP酶各亚基基因表达的改变，并观察钙通道阻滞剂维拉帕米对其影响，探讨内洋地黄素在MIR损伤细胞内钙超载中的可能作用及其机制。方法：24只雄性SD大鼠随机分成3组，每组8只。假手术组：丝线穿过左冠状动脉前降支，但不结扎：缺血再灌注组（MIR组）：结扎左冠状动脉前降支30min，再灌注45min；维拉帕米组：MIR模型＋5mg／kg维拉帕米，维拉帕米于再灌注前5min经股静脉注射。取缺血区左室心肌检测心肌匀浆内洋地黄素水平、心肌细胞膜Na^＋-K^＋-ATP酶和Ca^2＋-Mg^2＋-ATP酶活性、线粒体Ca^2＋浓度；免疫组化方法检测心肌Na^＋-K^＋-ATP酶α1、α2、α3和β1亚基蛋白水平表达的改变。结果：MIR损伤时，心肌组织内洋地黄素水平明显升高，心肌细胞膜Na^＋-K^＋-ATP酶和Ca^2＋-Mg^2＋-ATP酶活性显著下降，线粒体Ca^2＋浓度升高，Na^＋-K^＋-ATP酶α1、α2、α3和β1亚基蛋白水平表达均明显下降；维拉帕米除具有降低线粒体Ca^2＋浓度外，对缺血再灌注引起的其它各项异常指标无明显改善作用。结论：MIR促进机体内洋地黄素分泌增加，后者可能通过影响心肌细胞膜上的Na^＋-K^＋-ATP酶α1、α2、α3和β1亚基基因表达，抑制Na^＋-K^＋-ATP酶活性，导致线粒体内Ca^2＋超载。     

Physical-chemical-activity relationship of organic solvents: Effects on Na-K-ATPase activity and membrane fluidity in mouse synaptosomes

Physical-chemical-activity relationship of aromatic hydrocarbons (n = 10) and alkyl acetates (n = 16) with respect to their in vitro effects on synaptosomal membranes was studied. Na⁺-K⁺-adenosine triphosphatase (Na⁺-K⁺-ATPase) activity and membrane fluidity, which was determined using the fluorescence probe 1,6-diphenyl-1,3,5-hexatriene, were used as potential indicators of neuronal cell toxicity. The potency of inhibition for the enzyme (IC₅₀), the potency of increasing membrane fluidity (IC_12.5), and n-octanol/water partition coefficient (P) were all determined experimentally for 26 solvents. Correlation analyses were made on aromatic hydrocarbons and on alkyl acetates. There were linear relationships between log P and pIC₅₀ (log1/IC₅₀) values, and between log P and pIC_12.5 (logl/IC_12.5) values, indicating that the hydrophobicity of the solvents determines their toxic ability to affect membrane environment; the more hydrophobic the solvents are, the more toxic they are. A direct linear relationship between Na⁺-K⁺-ATPase activity pIC₅₀ and membrane fluidity pIC_12.5 values was also shown. This predictive correlation suggests a similar mechanism of membrane surface interaction govering both processes that are common to the test solvents. The present results confirm the importance of the lipid environment of neuronal membranes in maintaining the normal function of membrane-bound protein.     

Hypokalemic thyrotoxic periodic paralysis: clinical characteristics and predictors of recurrent paralytic attacks

Background and purpose:  To study the clinical characteristics of hypokalemic thyrotoxic periodic paralysis (hoTPP) and identify the predictors of recurrent paralytic attacks before achieving the euthyroid status.
Methods:  We retrospectively analyzed 45 hoTPP patients who were admitted during the 7-year study period.
Results:  A tendency towards male predominance was observed among the 45 patients (91.1%, 41/45). The mean onset age was 32.9 ± 10.0 years (range: 16–54 years). No significant differences were observed in the onset age between male and female patients. Precipitating factors included rest/sleep at night, hot weather, upper respiratory tract infections (URIs), and excessive physical activities. Atypical weakness was observed in nine (20%, 9/45) patients. One patient initially diagnosed with sporadic periodic paralysis eventually developed hoTPP.
Discussion:  In provocative tests, hypokalemia was not a consistent finding during paralytic attacks. Before achieving the euthyroid status, the rate of recurrent attacks was as high as 62.2%, and peaked in the first 3 months after hoTPP was diagnosed. Patients with URIs exhibited a higher incidence of recurrent paralytic attacks than those without (odds ratio = 13.00; 95% confidence interval = 1.08–156.08; P  =   0.04).     

Regulation of energy metabolism by creatine in cardiac and skeletal muscle cells in culture

Cardiac and skeletal muscle cells grown in culture were used in experiments designed to test the regulatory function of creatine. An increased concentration of intracellular phosphorylcreatine resulted from the addition of creatine to the growth media and the addition of metabolic inhibitors prevented the new high steady state concentration without depletion of ATP. With 1-fluoro-2, 4-dinitrobenzene the high concentration of phosphorylcreatine remained unchanged, while ATP was depleted. The use of the inhibitors provided additional evidence for creatine as the effector molecule in a feedback regulation of energy production, and for phosphorylcreatine in the regulation of energy charge at the contractile site. The effect of creatine on the fusion of myoblasts into myotubes supported its role in the control of cellular functions other than those involved in the energy metabolism. The correlation of the growth of muscle with increased muscular activity might be mediated through creatine, the end product of muscle activity. Creatine, synthesized in tissues other than muscle, might be involved in the coordination of muscle development throughout the body. Furthermore, it is suggested that the metabolic regulatory function of creatine is limited to the cells which do not synthesize creatine de novo, while in the tissues, such as the liver and kidney which have the mechanism for de novo synthesis of creatine, the absence of mitochondrial CPK precludes metabolic regulation of ～ P synthesis by creatine.     

Ca(2+)-ATPase and Na(+)-K(+)-ATPase content in skeletal muscle from malignant hyperthermia patients.

The purpose of this study was to determine the concentration of Ca(2+)-ATPase and Na(+)-K(+)-ATPase in biopsies from vastus lateralis muscle of 24 patients, who underwent a diagnostic contracture test for susceptibility to malignant hyperthermia (MH). Ca(2+)-ATPase was quantified as the Ca(2+)-dependent 32P incorporation in whole muscle homogenates. Na(+)-K(+)-ATPase was quantified as the [3H]ouabain-binding capacity in intact muscle samples. These methods avoid isolation of membranes, a procedure that may influence the results due to interindividual variation in recovery. The results show that both enzymes can be determined in (frozen) muscle biopsies weighing 50 mg. Neither the concentration of Ca(2+)-ATPase nor that of Na(+)-K(+)-ATPase differed in biopsies from subjects diagnosed as susceptible (MHS) or nonsusceptible (MHN) to MH. Our data support the view that changes in the concentration of Ca(2+)-ATPase and/or Na(+)-K(+)-ATPase do not play a primary role in the pathogenesis of MH.