阿米洛利对压力超负荷心肌肥厚大鼠心肌细胞内游离钙的影响

目的:观察阿米洛利预防性给药对压力超负荷心肌肥厚大鼠心肌细胞[Ca²⁺]i 影响。方法:以Fura-2/AM为指示剂,测定单细胞[Ca²⁺]i。结果:压力超负荷大鼠左室心肌细胞[Ca²⁺]i 升高,阿米洛利和依那普利组则[Ca²⁺]i 明显降低。给予KCl,NE刺激后,给药组左室心肌细胞[Ca²⁺]i 的增加值明显低于左室肥厚组,百日咳毒素(PTX,100 ng·L^-1) 处理5 h 后,其静息[Ca²⁺]i 无显著变化,但抑制NE诱导左室心肌细胞[Ca²⁺]i 升高,该作用在左室肥厚组更明显,对KCl 刺激引起的[Ca²⁺]i 升高,给药组无影响,左室肥厚组的升高值略有增加。结论:NE所致心肌细胞[Ca₂₊]i 升高与PTX敏感的G 蛋白有关,肥厚时此途径亢进。     

甲状旁腺素对人甲状腺髓样癌细胞增殖和凋亡的影响

目的探讨甲状旁腺素对人甲状腺髓样癌细胞体外增殖抑制及凋亡作用。方法体外培养甲状腺髓样癌细胞株,经甲状旁腺素和甲状旁腺素受体单抗干预处理后,倒置相差显微镜下观察细胞生长状况,流式细胞仪检测细胞凋亡。结果倒置相差显微镜下细胞变化明显,各浓度的甲状旁腺素和甲状旁腺素受体单抗均分别能有效地抑制甲状腺髓样癌细胞增殖、诱导细胞凋亡,凋亡作用呈时间和浓度依赖。当甲状旁腺素浓度为2.0μmol/L、甲状旁腺素受体单抗浓度为1.0μmol/L时,对细胞凋亡作用显著(P0.05),凋亡率分别为13.24%及20.78%。结论甲状旁腺素对人甲状腺髓样癌细胞增殖有抑制作用并能诱导其凋亡。     

细胞内游离钙与柯萨奇病毒B3诱导的大鼠培养心肌细胞凋亡

目的 探讨（Ｃａ＾２＋）ｉ在柯萨奇病毒（ＣＶ）Ｂ３诱导心肌培养细胞凋亡中的作用。方法 ＤＮＡ裂点检测法（３′－末端标记）及扫描电镜检测细胞凋亡。Ｆｌｕｏ３－ＡＭ负载心肌细胞,共聚劁业微镜观察（Ｃａ＾２＋）ｉ荧光强度变化。结果：感染２４ｈ,心肌细胞内ＣＶＢ３的浓度达峰值,感染１０ｈ未见凋亡的心肌细胞,１７,２４和３６ｈ凋亡细胞分别为５％,６０％和９０％,感染１７ｈ心肌（Ｃａ＾２＋）ｉ浓度达峰值,电镜     

脂联素对高糖环境下人心肌细胞增殖和凋亡的干预作用

目的探讨脂联素（Adiponectin,ADPN）对高糖环境下人心肌细胞增殖、凋亡的影响,揭示脂联素在糖尿病心肌病变中的保护作用。方法将人心肌细胞用5.5mmol/L葡萄糖（正常对照组）、30.0mmol/L葡萄糖（高糖组）、30.0mmol/L＋2.5μg/mlADPN（脂联素组）分别培养24h,48h,72h后,运用MTT方法检测细胞增殖,Westernblotting检测凋亡相关蛋白Bax,Bcl-2的表达,用荧光探针DCFH-DA检测细胞内ROS水平,观察细胞凋亡。结果①高糖组人心肌细胞增殖被抑制（P〈0.05）,ROS水平、细胞凋亡增加,并呈时间依赖性。②高糖组人心肌细胞,脂联素（2.5μg/ml）干预后,细胞增殖接近正常对照组,ROS水平下降,延缓了细胞凋亡。高糖环境下随着时间的延长,可引起心肌细胞增生肥大,诱导其凋亡;脂联素可促进细胞增殖,延缓细胞凋亡。     

甲状旁腺素对维持性血液透析患者的红细胞寿命和细胞内钙离子的影响

目的探讨在血液透析(HD))患者中,全段甲状旁腺素(iPTH)、红细胞寿命(RCS)和红细胞内游离钙离子浓度(E[Ca~(2+)]i)三者之间的相关性,以及PTH对RCS和(E[Ca~(2+)]i的影响。方法选择维持性HD一年以上的患者23例,按i PTH的水平不同分为两组(≤350 pg/ml组和>350 pg/ml组)。采用51Cr标记法测定RCS,钙荧光指示剂Fura-3法测定E[Ca~(2+)]i,采用Roche电化学发光分析仪检测iPTH。结果iPTH≤350 pg/ml组的RCS为(23.36±3.17)d,i PTH>350 pg/ml组为(18.67±3.25)d,两组之间的RCS存在显著的统计学差异(P<0.01),在RCS与PTH两者之间存在显著统计学意义的负相关(r=-0.754,P<0.001)。iPTH≤350 pg/ml组的E[Ca~(2+)]i浓度为(2.53±0.37)nmo I/L,i PTH>350 pg/ml组E[Ca~(2+)]i浓度为(2.04±0.34)nmo I/L,两组之间的E[Ca~(2+)]i浓度存在显著的统计学差异(P<0.001)。在E[Ca~(2+)]i浓度与PTH水平之间,两者存在显著统计学意义的正相关(r=0.82,P<0.001)。在E[Ca~(2+)]i浓度与RCS天数之间,两者存在显著统计学意义的负相关(r=-0.67,P<0.01)。结论过量分泌的i PTH可以导致HD患者的RCS缩短和E[Ca21]i浓度增加。RCS和E[Ca21]i浓度之间又有密切的关联性。最终,i PTH有可能通过增加红细胞内Ca~(2+)导致RCS缩短,对HD患者的贫血产生不良的影响。     

甲状旁腺素和甲状旁腺素相关肽在皮肤病中的研究进展

甲状旁腺素（ PTH）和甲状旁腺素相关肽（ PTHrP）是一类多肽类激素,它们具有相似的基因结构、相同的膜受体,在人体钙、磷代谢过程中起着重要的调节作用。 PTH和PTHrP及其受体除表达于肿瘤组织外,在皮肤、毛囊等正常组织也有表达。它们对表皮增殖分化、毛发生长的生理作用等方面,有望成为银屑病等常见皮肤病的治疗新靶点。     

环维黄杨星D升高心肌细胞内游离钙浓度实验研究

观察了环维黄杨星D（CVB－D）对急性分离心肌细胞内游离Ca^2 浓度的影响。应用特异性荧光指示剂Fluo-3/AM负载细胞,用激光共聚焦显微镜检测胞内游离钙的变化。结果表明,CVB－D在10^-5,10^-4mol/L时均可升高心肌细胞内游离钙离子浓度,此作用随剂量增加而增加。因此,CVB－D具有升高心肌细胞内游离钙离子浓度的作用。     

广枣总黄酮对心肌细胞内游离钙浓度的影响

目的：研究广枣总黄酮（TFC）对心肌细胞内游离钙浓度的影响。方法：以大白鼠作为受试动物，随机分为6组，其中4组为TFC等比剂量（6，12，24，48mg/kg）给药组，用灌胃法给药15d后测定其心肌细胞内Ca^2 浓度；另两组分别为阳性对照组和阴性对照组。结果：用药组大鼠心肌细胞内Ca^2 浓度降低，与阴性对照组比较差异显（P＜0．01），且Ca^2 浓度降低的程度与TFC剂量呈正相关。结论：TFC能降低心肌细胞内Ca^2 浓度可能是广枣在临床被用于治疗心脏病症的机理。     

Vasopressin-evoked [Ca2+]i responses in neonatal rat cardiomyocytes.

The presence of arginine vasopressin (AVP) V1 receptors on neonatal rat cardiomyocytes (NRCs) linked to processes capable of elevating intracellular free calcium ([Ca2+]i) is now firmly established. This study examined the sources and signaling involved in [Ca2+]i elevations evoked by AVP in NRCs. AVP promoted increases in both [Ca2+]i and 1,4,5-inositoltrisphosphate (IP3) levels in NRCs. The degree of [Ca2+]i elevation was less than that of angiotensin II, but greater than that of endothelin-1. Extracellular Mg2+ depletion led to diminution of the maximal [Ca2+]i response, with a rightward shift in the concentration-response curves to AVP. The phospholipase C inhibitors, D-609, NCDC, or U73122, and the IP3 receptor blocker, heparin, abolished the [Ca2+]i response to AVP. Neither cyclooxygenase inhibition with indomethacin nor PKC inhibition with staurosporine had any effect. Neither ryanodine nor caffeine, which deplete sarcoplasmic reticulum (SR) Ca2+ stores, nor ruthenium red, which inhibits both SR and mitochondrial Ca2+ stores, affected [Ca2+]i responses to AVP. The SR Ca2+ pump inhibitor, cyclopiazonic acid, abolished, and removal of extracellular Ca2+ attenuated, the response to AVP. These data indicate that activation of cardiac V1 receptors by AVP results in mobilization of Ca2+ from a distinct, non-SR, nonmitochondrial, intracellular Ca2+ pool that is Ca2+ pump replenished and IP3 sensitive. This process occurs secondary to phospholipase C (PLC)-mediated generation of IP3, requires the presence of Mg2+ and extracellular Ca2+, and occurs in a manner independent of PKC and cyclooxygenase activation. Such mechanisms of Ca2+ mobilization might indicate a distinct role for AVP in cardiac physiology and disease.     

人参皂苷Rb1对H_2O_2诱导新生大鼠心肌细胞凋亡的保护作用

目的观察人参皂苷Rb1对H2O2诱导的新生大鼠心肌细胞凋亡的保护作用,并探讨其可能作用机制。方法在培养的新生大鼠心肌细胞上建立H2O2损伤模型,观察不同剂量组人参皂苷Rb1(20、40、80mg·L-1)对心肌细胞凋亡率、丙二醛(MDA)含量,超氧化物歧化酶(SOD)活性,以及细胞内钙离子变化的影响。结果不同剂量组人参皂苷Rb1可以减少心肌细胞凋亡率、降低MDA含量、增加SOD活性、减少细胞内钙超载。结论人参皂苷Rb1可以抑制H2O2引起的新生大鼠心肌细胞凋亡,其作用机制可能与其抗脂质氧化和减少细胞内钙超载有关。     

甲状旁腺激素构效关系的研究进展

甲状旁腺激素(PTH)是生物体内调节钙、磷代谢最为重要的肽类激素之一,其氨基端1-34片段具有全分子PTH与受体结合的能力及生物活性,被广泛用于研究PTH的结构与功能。PTH二级结构中富含α-螺旋,该螺旋结构在PTH与受体相互作用中起重要作用,其中羧基端负责与受体结合,氨基端负责生理活性。现从甲状旁腺激素的结构、与受体的相互作用和构效关系等角度出发,综述了甲状旁腺激素近年来的研究状况,为开发新型骨质疏松症治疗药物提供理论依据。     

不同类型黄酮对过氧化氢诱导的心肌细胞凋亡的影响

目的：观察不同类型的黄酮类化合物红花黄色素A（查儿酮）、高良姜素（黄酮醇）、陈皮素（二氢黄酮）对H2O2诱导的心肌细胞凋亡及Bcl-2、Bax、Caspase-3蛋白表达的影响。方法：取Wistar大鼠乳鼠心肌细胞做原代培养，制备H2O2诱导的心肌细胞凋亡模型。MTT法检测3种黄酮类化合物适宜的实验浓度，TUNEL法、流式细胞术检测细胞凋亡率，免疫组化法测定Bcl-2、Bax、Caspase-3蛋白表达。结果：MTT法显示各组药物只有5μmol／L组与空白组相比差异无统计学意义（P〈0．05）。仅30μmol／L组细胞活力显著高于模型组，随后实验选用30μmol／L作为试验浓度。TUNEL法检测细胞凋亡率，除红花黄色素A组外各药物组细胞凋亡率均显著小于模型组（P〈0．05）。流式细胞术检测显示，各药物组均能降低细胞凋亡率和坏死率。免疫组化显示，Caspase-3蛋白阳性表达除红花黄色素A组（与空白对照组比较P〉0．05）外各药物组均显著小于模型组（P〈0．05）。Bcl-2／Bax比值除红花黄色素A组（与正常组比较P〉0．05）外各药物组均显著高于模型组（P〈0．05）。TUNEL法检测凋亡率、Caspase-3蛋白阳性表达、Bcl-2／Bax比值均显示陈皮素和高良姜素组间无统计学差异（P〉0．05）。结论：陈皮素和高良姜素抑制100tnnol／LH2O2诱导新生乳鼠心肌细胞凋亡的效果相当，可调节Bcl-2、Bax、Caspase-3蛋白表达，起到保护心肌细胞作用；而红花黄色素A对细胞坏死的影响可能比对细胞凋亡的作用更强。     

PTH2 receptor-mediated inhibitory effect of parathyroid hormone and TIP39 on cell proliferation

The parathyroid hormone (PTH) has dual mitogenic and inhibitory effects on cell proliferation, depending on the cell type and experimental conditions. PTH can signal via two different receptors, both positively coupled to the adenylyl cyclase/cyclic AMP pathway which can mimic some of the proliferative effects of PTH. We evaluated the role of the type-2 PTH (PTH2) receptor on cell proliferation in clonal human embryonic kidney HEK293 cells stably expressing the human PTH2 receptor. Using a cyclic AMP-responsive gene-reporter, we confirmed that the tuberoinfundibular peptide (TIP39) and various human (h) PTH fragments including hPTH-(1-34) were potent agonists (EC(50) in the range of 0.01-0.3 nM) whereas the bovine (b) PTH peptides b(Tyr(34))PTH-(7-34) and its tryptophan derivative b[D-Trp(12),Tyr(34)]PTH-(7-34) behaved as antagonists (IC(50)=117 and 249 nM, respectively). hPTH-(1-34) produced a dose-dependent inhibition of cell proliferation (EC(50)=8.5+/-0.4 nM) after 3 days and this effect was fully reversed by the tryptophan derivative antagonist. The same effect was observed with TIP39 which caused a 30% maximal inhibition. These findings reveal that PTH2 receptor activation can inhibit cell proliferation and might explain the dual functionality of PTH on cell proliferation.     

Effect of stannous chloride on rat femur

Oral administration of stannous chloride (SnCl₂) (1.0 mg $\text{Sn}{}^{\mathrm{2+}}\text{kg}$ body weight) to rats, twice daily for 30 or 90 days, caused a significant decrease of the calcium (Ca) content and acid phosphatase activity of the femoral epiphysis but did not reduce those of the femoral diaphysis. 1.0 mg $\text{Sn}{}^{\mathrm{2+}}\text{kg}$ for 30 days produced a significant decrease of alkaline phosphatase activity of the femoral epiphysis, but did not lower that of the femoral diaphysis. The results indicate that Sn may inhibit bone formation directly in the femoral epiphysis of rats.     

Effects of ovariectomy and 17 beta-oestradiol replacement on [Ca2+]i in female rat cardiac myocytes

1. The present study investigated the effects of ovariectomy (OVX) and 17beta-oestradiol replacement on [Ca2+]i in rat freshly isolated cardiac myocytes. 2. Myocytes were isolated from the hearts of sham, OVX and OVX + 17beta-oestradiol-replaced female rats by enzymatic digestion with collagenase. Changes in [Ca2+]i in response to varied extracellular [Ca2+] were measured using the Ca2+-sensitive dye fura-2, with the contractile responses of each cell measured as cell shortening. 3. Increasing extracellular [Ca2+] resulted in increased [Ca2+]i in all three groups. Peak [Ca2+]i and the amplitude of the Ca2+ transient were significantly greater (P < 0.01) in cells from OVX animals compared with cells from both sham and 17beta-oestradiol-replaced OVX animals. 4. The time-course of decay of the Ca2+ transient was significantly faster (P < 0.02) in OVX cells compared with both sham and 17beta-oestradiol-replaced cells. In addition, time to 50% relaxation was significantly faster (P < 0.04) and extent of shortening significantly greater (P < 0.01) in OVX cells than in either sham or 17beta-oestradiol cells. 5. These data demonstrate clear differences in peak [Ca2+]i and the amplitude of the Ca2+ transient between OVX female rat cardiac myocytes compared with intact and 17beta-oestradiol-replaced OVX female rat cardiac myocytes. This suggests that oestrogen may play a long-term role in limiting Ca2+ entry into the cardiac myocyte.     

RP-HPLC法测定注射用重组人甲状旁腺素含量

目的:建立RP-HPLC法测定注射用重组人甲状旁腺素的含量。方法:色谱柱为Agilent Zorbax 300SB C18(150 mm×4.6 mm,3.5μm),流动相为0.2 mol.L-1硫酸盐缓冲液(pH2.3)-乙腈(75∶25),流速0.8 mL.min-1,检测波长为214 nm,柱温为40℃。结果:线性范围:在10~30μg.mL-1浓度范围内与峰面积呈良好线性关系(r=0.9997,n=5),最低检出限为20 ng,平均回收率为99.8%(n=9)。结论:本方法准确,重复性好,可为注射用重组人甲状旁腺素质量评价提供较为可靠的分析方法。     

碘化N-正丁基氟哌啶醇对大鼠心肌细胞内钙离子的影响

目的:研究碘化N-正丁基氟哌啶醇(F2)对大鼠心肌细胞内钙离子([Ca2+]i)的影响。方法:采用钙荧光染料Fluo-3-AM负载心肌细胞,在激光扫描共聚焦显微镜上测定细胞内钙离子的变化。结果:在含钙(1.8mmol·L-1)台式液中,60mmol·L-1KCl使细胞内钙荧光强度由1.0增高至1.84±0.35(P<0.01,n=50),分别用0.1、1、10μmol·L-1F2预先孵育心肌细胞,F2可以浓度依赖地抑制钙荧光强度的增高,IC50为1.61μmol·L-1。0.1、1、10μmol·L-1F2使得KCl诱导增高的钙荧光强度从1.92±0.42分别降至1.88±0.39、1.31±0.36和1.09±0.05(P分别>0.05、<0.01和<0.01,n=50),IC50为1.78μmol·L-1。F2不影响静息状态下的细胞内钙的浓度。对咖啡因和三磷酸肌醇介导的细胞内钙的释放均无作用。结论:F2通过阻断心肌细胞膜电压依赖性钙通道降低心肌细胞内钙浓度,这可能是保护心肌缺血/再灌注损伤的机制。