降钙素治疗膝骨关节炎的疗效观察

目的:观察和评价应用密盖息治疗膝骨关节炎的疗效.方法:40例女性病人,年龄50-75岁,平均年龄65岁,均经过临床X线检查确诊,应用密盖息四周后,对疼痛缓解时间、功能恢复情况进行疗效评估,并经一年门诊随访,总结其疗效.结果:随访1年后,统计达到优20例,良17例,无效3例,总有效率80%以上.结论:密盖息对膝骨关节炎治疗达到止痛、控制和预防膝骨关节内翻、外翻畸形,在临床治疗提高疗效起到巨大的作用.     

降钙素和降钙素基因相关肽的选择性表达

降钙素和降钙素基因相关肽(CT/CGRP)由同一基因编码,该基因结构及其5＇端侧翼序列决定了它能够在甲状腺C细胞以及中枢和外周神经细胞生成不同的表达产物.这种选择表达调控决定多细胞生物的发育、性别分化和进化.如果表达失控将导致甲状腺髓样瘤(MTC)和骨质疏松症等疾病.文章对该基因的结构和选择性表达调控进行了综述.     

Modulation of Calcitonin Binding by Calcium: Differential Effects of Divalent Cations

Abstract

Binding of salmon calcitonin to bovine hypothalamic membranes is enhanced about 25% by calcium with a half-maximal effect at 15 mM calcium. In contrast, membranes prepared from a cell line expressing a recombinant human calcitonin receptor show no effect of calcium under similar conditions. The hypothalamic calcitonin receptor solubilized with CHAPS detergent retains an apparent Kd of 0.3 nM for salmon calcitonin; however, binding of calcitonin to the detergent-solubilized receptor complex can be inhibited by divalent cations in order of potency Mn>Ca Sr Mg NaCl with Mn and Ca having apparent Ki's of 5 mM and 20 mM respectively. Dixon and Scatchard plots of Mn and Ca inhibition of binding to the soluble receptor complex suggest a noncompetitive mechanism of inhibition. Calcium also inhibits calcitonin binding to a detergent-solubilized recombinant human calcitonin receptor. Inhibition of calcitonin binding is observed using two independent methods for determining soluble receptor-hormone complex and inhibition is reversed by EDTA.     

Activation of Calcitonin Receptor and Calcitonin Receptor-like Receptor by Membrane-anchored Ligands

G protein-coupled receptors (GPCRs) are the most important pharmaceutical targets, and more than 40% of drugs in use today modulate GPCR signaling. A major hurdle in the development of therapies targeting GPCRs is the drug candidate''s nonselective actions in multiple tissues. The ability to spatially control GPCR signaling would provide a venue for developing therapies that require targeted GPCR signaling. Here, we show that the fusion of a RAMP1 co-receptor with the calcitonin gene-related peptide (CGRP), or calcitonin, transforms the RAMP1 from a co-receptor to bona fide membrane-anchored ligands (CGRP-RAMP1 and CAL-RAMP1). The CAL-RAMP1 selectively activates the calcitonin receptor (CR), whereas, the CGRP-RAMP1 activates both the calcitonin receptor-like receptor (CLR) and CR. Unlike a free peptide, which moves freely in the extracellular space and differentiates targets based on molecular affinity, the anchored CGRP-RAMP1 and CAL-RAMP1 ligands confine their activities to individual cells. In addition, our study showed that a CGRP8–37-RAMP1 chimera, but not RAMP1, functions as an antagonist for CGRP-RAMP1-mediated signaling, suggesting that the activation of CLR by CGRP-RAMP1 shares similar molecular mechanisms with the CGRP-mediated activation of CLR/RAMP1 receptor complexes. Taken together, our finding thus provides a novel class of ligands that activate CR and CLR exclusively in an autocrine manner and a proof-of-concept demonstration for future development of targeted therapies aimed at these receptors in specific cell populations.     

降钙素基因相关肽的研究

降钙素基因相关肽(cGRP)是近年来发现的一种新肽,广泛分布于中枢和外周神经系统以及某些非神经组织,在心血管和消化道等部位尤其丰富;它参与机体多种调节扼制,特别是感觉和胃肠功能的调节,对血压、血流、心率等也有较强的调节作用。     

降钙素基因相关肽家族受体及其受体活性修饰蛋白

降钙素基因相关肽家族是一类多功能的激素家族 ,参与人体的多种生物学功能 ,与多种疾病有关。降钙素基因相关肽受体包括降钙素受体 (CTR)和降钙素受体样受体 (CRLR) ,CTR可以独自与降钙素结合 ,而CRLR必须与一组称作受体活性修饰蛋白 (RAMPs)的蛋白质共同作用才能发挥生物学功能。综述CTR的研究概况及CRLR与RAMPs相互作用的机制和表达调控 ,以期为人们设计新型药物提供参考。     

Fibrillation of Human Calcitonin and Its Analogs: Effects of Phosphorylation and Disulfide Reduction

Some therapeutic peptides self-assemble in solution to form ordered, insoluble, β-sheet-rich amyloid fibrils. This physical instability can result in reduced potency, cause immunogenic side effects, and limit options for formulation. Understanding the mechanisms of fibrillation is key to developing rational mitigation strategies. Here, amide hydrogen-deuterium exchange with mass spectrometric analysis (HDX-MS) coupled with proteolytic digestion was used to identify the early stage interactions leading to fibrillation of human calcitonin (hCT), a peptide hormone important in calcium metabolism. hCT fibrillation kinetics was sigmoidal, with lag, growth, and plateau phases as shown by thioflavin T and turbidity measurements. HDX-MS of fibrillating hCT (pH 7.4; 25°C) suggested early involvement of the N-terminal (1–11) and central (12–19) fragments in interactions during the lag phase, whereas C-terminal fragments (20–32 and 26–32) showed limited involvement during this period. The residue-level information was used to develop phosphorylated hCT analogs that showed modified fibrillation that depended on phosphorylation site. Phosphorylation in the central region resulted in complete inhibition of fibrillation for the phospho-Thr-13 hCT analog, whereas phosphorylation in the N-terminal and C-terminal regions inhibited but did not prevent fibrillation. Reduction of the Cys1-Cys7 disulfide bond resulted in faster fibrillation with involvement of different hCT residues as indicated by pulsed HDX-MS. Together, the results demonstrate that small structural changes have significant effects on hCT fibrillation and that understanding these effects can inform the rational development of fibrillation-resistant hCT analogs.     

Effects of Renal Denervation on Renal Artery Function in Humans: Preliminary Study

Aim

To study the effects of RD on renal artery wall function non-invasively using magnetic resonance.

Methods and Results

32 patients undergoing RD were included. A 3.0 Tesla magnetic resonance of the renal arteries was performed before RD and after 6-month. We quantified the vessel sharpness of both renal arteries using a quantitative analysis tool (Soap-Bubble®). In 17 patients we assessed the maximal and minimal cross-sectional area of both arteries, peak velocity, mean flow, and renal artery distensibility. In a subset of patients wall shear stress was assessed with computational flow dynamics. Neither renal artery sharpness nor renal artery distensibility differed significantly. A significant increase in minimal and maximal areas (by 25.3%, p = 0.008, and 24.6%, p = 0.007, respectively), peak velocity (by 16.9%, p = 0.021), and mean flow (by 22.4%, p = 0.007) was observed after RD. Wall shear stress significantly decreased (by 25%, p = 0.029). These effects were observed in blood pressure responders and non-responders.

Conclusions

RD is not associated with adverse effects at renal artery level, and leads to an increase in cross-sectional areas, velocity and flow and a decrease in wall shear stress.     

Calcitonin receptors of human osteoclastoma

Osteoclast-rich cultures were prepared by disaggregation of osteoclastomas (giant cell tumour of bone) and settlement onto glass or plastic surfaces. Autoradiography using [125I]-salmon calcitonin ([125I]-sCT) revealed specific binding only to multinucleate giant cells (osteoclasts) and a minor population of mononuclear cells. [125I]-sCT competitive binding studies indicated a Kd of 5 x 10(-10) M and receptor number of approximately 1 million sites/osteoclast. sCT treatment resulted in a dose-dependent rise in cAMP (EC50 10(-10) M). Homogenates of an osteoclastoma also demonstrated specific binding of [125I]-sCT. Chemical cross-linking of a labelled synthetic sCT derivative. [125I]-[Arg11,18,Lys14]-sCT, using disuccinimidyl suberate, resulted in labelling of a receptor component of approximate Mr 85-90,000. The multinucleate giant cells (osteoclasts) of human osteoclastomas possess large number of CT receptors which exhibit the same binding kinetics and apparent Mr as those of other CT target cells.     

降钙素与骨质疏松的治疗

骨质疏松症是常见的老年性疾病,日前尚无有效的预防和治疗手段。降钙素是一种多肽激素,能调节体内钙的代谢,对骨质疏松症有一定的疗效。本文简要阐述了降钙素用于治疗骨质疏松症的机理、方法、效果以及应用前景。     

Calcitonin and prostaglandin system

It has been repeatedly reported that calcitonin treatment in various diseases with high levels of bone resorption is associated with an antalgic effect, the mechanism of which is far from been clarified. The involvment of prostaglandins and thromboxane in hyperalgesia prompted us to consider the possibility that calcitonin induces its antalgic effect through on interference with prostaglandin and thromboxane synthesis. Guinea pig lung which, perfused with arachidonic acid releases in the perfusate a mixture of thromboxane and prostaglandins, each measurable on a separate smooth muscle tissue (rabbit aorta and rat stomach strip), was used as a test system. Calcitonin added to the perfusion fluid was shown to inhibit the synthesis both of prostaglandins and thromboxane. The concentration of calcitonin (salmon) which decreased the activity of arachidonic acid by 50% (KB) was 0.27 and 0.40 nmoles for prostaglandins and thromboxane respectively. In the experiments carried out using Ca⁺⁺ concentration in the perfusion fluid 50% higher than normal (0.28 g/l), calcitonin inhibition of prostaglandins and thromboxane was unchanged (KB = 0.23 and 0.36 nmoles respectively). The reported results by indicating that calcitonin has an influence on cyclooxygenase as indomethacin (used as reference standard) whose it is well known the activity at this level, support the interesting possibility that the antalgic effect consequent to the treatment with the hormone is due, at least in part, to a mechanism involving the prostaglandin synthetase system.     

慢性肾缺血致心功能不全时大鼠心肌组织降钙素基因相关肽含量的变化

目的观察慢性肾缺血导致心功能不全时心肌组织降钙素基因相关肽（CGRP）含量变化,并分析变化的机制。方法将40只Wistar大鼠分为,狭窄对照组（n=15）和狭窄治疗组（n=15）,均采用两肾动脉之间腹主动脉缩窄术造成单侧慢性肾缺血。假手术组（n=10）仅分离腹主动脉。至术后16周狭窄治疗组给予阿魏酸钠40mg／kg腹腔内注射,狭窄对照组和假手术组均给予同等剂量生理盐水。治疗2周后,测定颈动脉压、左心功能,处死大鼠后测定心肌组织CGRP、ET-1和NO含量,分别测定心肌和脊髓背根神经节CGRP mRNA表达。结果狭窄对照组和狭窄治疗组心功能均下降,但狭窄治疗组心脏舒张功能优于狭窄对照组。狭窄对照组心肌内ET-1含量明显增加,CGRP含量明显下降。狭窄治疗组心肌内ET-1含量较对照组减少,CGRP含量略增高。各组心肌CGRP mRNA表达无明显差异。狭窄治疗组脊髓背根神经节CGRP mRNA表达较假手术组增加。结论大鼠慢性肾缺血导致心脏组织ET-1持续激活,CGRP、NO合成受损,与心功能下降密切相关。心功能不全时,脊髓背根神经节CGRP mRNA表汰代偿件增高,但心脏血管内皮绢织受损可能是心脏CGRP含量下降的主要因素。     

葛根素对甘油致急性肾功能衰竭兔血液流变学和肾血流量的影响

目的 肌注甘油复制急性肾功能衰竭(ARF)兔模型,观察葛根素(Pue)对ARF兔血液流变学和肾血流量的影响.方法 健康雄性日本大耳白兔30只,随机分为正常组、ARF模型组、Pue 1组(20 mg/kg)、Pue 2组(40mg/kg)、Pue 3组(80 mg/kg).各组于不同时间点测量其肾血流量、血液流变学指标和肾功能指标(Cr、BUN),并观察肾组织形态学改变.结果 与模型组比较,Pue 2组和Pue 3组治疗后各时间点Cr、BUN降低(P＜0.05),血液流变学指标降低明显(P＜0.05),肾血流量增加差异具有统计学意义(P＜0.05).Pue 2组和Pue 3组肾小管上皮细胞肿胀减轻,管型少见.结论 葛根素可明显改善急性肾功能衰竭兔血液流变性,增加肾血流量,进而达到改善、减轻肾小管损害的作用.     

比较L-精氨酸、肌苷对肾脏功能保护的实验研究

探讨L-精氨酸(L-Arg)的肾功能保护作用机制及与肌苷的疗效比较。模拟手术肾损伤模型,分别采用放射免疫法和硝酸还原酶法检测手术前后大鼠不同时期尿液β2-MG、血浆NO含量变化。结果表明L-Arg和肌苷均对肾功能损伤有明显保护作用,L-Arg比肌苷更快地促进肾功能的恢复。