Preparation and characterization of a novel strontium-containing calcium phosphate cement with the two-step hydration process

A novel Sr-containing calcium phosphate cement (CPC) with excellent compressive strength, good radiopacity and suitable setting time was developed in this work. The two-step hydration reaction resulted in a high compressive strength, with a maximum of up to 74.9 MPa. Sr was doped into the calcium-deficient hydroxyapatite as a hydrated product during the hydration reaction of the CPC. Because of the existence of Sr element and the compact microstructure after hydration, the Sr-containing CPC shows good radiopacity. It is expected to be used in orthopedic and maxillofacial surgery for bone defects repairing.     

Strontium ranelate,a promising disease modifying osteoarthritis drug

Introduction: The articular cartilage and subchondral bone may have potential crosstalk in the development and progression of osteoarthritis (OA). Strontium ranelate (SrR) has the ability to dissociate the bone remodeling process and to change the balance between bone resorption and bone formation. Its effect on subchondral bone makes it a potential disease- modifying osteoarthritis drug (DMOAD) in the treatment of OA. The aim of the current review is to summarize up-to-date pharmacological and clinical data of SrR for OA treatment.

Areas covered: A literature search was performed on PubMed and European Medicines Agency (EMA) website for all publications and documents related to SrR and OA. References of related studies were searched by hand. Treatment with SrR, especially at the dosage of 2 g/day, was associated with reduced radiographic knee OA progression, and with meaningful clinical improvement. It was also significantly associated with decreased MRI-assessed cartilage volume loss (CVL) and bone marrow lesions (BMLs).

Expert opinion: SrR could be a promising DMOAD particularly for OA patients with bone phenotypes. The clinical efficacy and side effects of SrR for OA treatment need to be further investigated in future clinical trials before clinical application.     

负载BMP-2掺锶磷酸钙复合材料对成骨细胞增殖及功能的影响

目的探索负载BMP-2掺锶磷酸钙复合材料对成骨细胞增殖及功能的影响。方法获取SD大鼠成骨细胞,随机分为空白对照组(Con组)、磷酸钙组(CPC组)和复合材料组(BSCPC组);培养基中分别添加安慰剂、磷酸钙和负载BMP-2掺锶磷酸钙共培养一段时间,通过CCK-8法检测成骨细胞的增殖情况,碱性磷酸酶(alkalinephosphatase,ALP)及茜素红染色观察细胞的功能状态,蛋白电泳观察骨保护素(osteoprotegerin,OPG)、核因子κB受体活化因子(receptor activator of nuclear factor-KB,RANK)及核因子κB受体活化因子配体(ligand of receptor activator of nuclear factor-κB,RANKL)蛋白的表达情况。结果共培养1、3、5和7 d,和Con组比较,CPC组和BSCPC组的成骨细胞数目明显增加(P0.05),且以BSCPC组成骨细胞数目最多(P0.05);共培养14 d及21 d,和Con组比较,CPC组和BSCPC组的成骨细胞的矿化能力及ALP活性明显增加(P0.05),且以BSCPC组细胞钙化能力最强及ALP活性最高(P0.05);共培养7 d,和Con组比较,CPC组和BSCPC组的成骨细胞的OPG表达明显增加,而RANK及RANKL蛋白表达明显降低(P0.05),且以BSCPC组的成骨细胞蛋白OPG、RANK及RANKL蛋白表达量改善最为显著(P0.05)。结论负载BMP-2掺锶磷酸钙复合材料促进成骨细胞增殖分化和改善细胞活性和功能。     

雷奈酸锶:翻开了治疗骨质疏松的新篇章

雷奈酸锶是一个新型抗骨质疏松制剂,它和以前所用治疗骨质疏松的药物不同,其对骨代谢具有双重作用,即抑制骨吸收和促进骨的形成.尽管其机制尚不清楚,但在组织和细胞培养中,雷奈酸锶可以促进前成骨细胞的增生和分化,促进骨基质的合成.同时雷奈酸锶还可以抑制破骨细胞分化和破骨细胞活性并刺激破骨细胞凋亡.在体内,雷奈酸锶可使正常的大鼠和小鼠骨形成增强和骨吸收降低,并可改善骨的微细结构.在卵巢切除大鼠,雷奈酸锶在保持高水平骨形成的同时抑制骨吸收,增加骨量和骨的强度.在临床实验中,雷奈酸锶不仅可以增加血清碱性磷酸酶(骨的形成指标)的水平,并可降低血清C-交联端肽I型胶原(骨的吸收指标)的水平.组织测量学研究显示,雷奈酸锶可以使成骨细胞的表面和骨的矿物质沉积率增加,而骨吸收的参数下降.雷奈酸锶可降低椎骨以及非椎骨新发骨折的危险性.这些前临床和临床实验结果 显示雷奈酸锶是安全、有效的抗骨质疏松药物,其刺激骨形成和抑制骨吸收的双重作用使其有可能成为抗骨质疏松的理想药物.     

89锶联合内分泌疗法治疗前列腺癌骨转移疼痛的疗效观察

目的 探讨^89锶（^89 Sr）联合内分泌疗法治疗前列腺癌骨转移性疼痛的疗效。方法 将36例确诊为前列腺癌且有多个部位骨转移病灶并伴有疼痛的患者随机分为两组：治疗组19例，给予^89 Sr联合内分泌疗法，对照组17例，单纯采用内分泌治疗。结果 治疗前两组患者的疼痛级数和骨转移灶数目间差异无显著性意义（P〉0、05）。治疗 后两组患者疼痛级数和骨转移病灶数间差异均有显著性意义（P〈0、05）。结论^89 Sr联合内分泌疗法不仅能有效缓解前列腺癌骨转移性疼痛，而且可破坏骨转移病灶，使之缩小或消退，疗效优于单纯内分泌疗法。     

Metastable Equilibrium Solubility Behavior of Carbonated Apatite in the Presence of Solution Strontium

The purpose of this study was to use the concept of metastable equilibrium solubility (MES) to describe the anomalous solubility behavior of carbonated apatite (CAP) in the presence of solution strontium. A CAP sample (4.8 wt% CO₃, synthesized at 70°C) was prepared by precipitation. Baseline MES distributions were determined in a series of 0.1 M acetate buffers containing only calcium and phosphate (no strontium) over a broad range of solution conditions. In order to assess the influence of strontium, MES profiles were then determined in a similar fashion with 20, 30, 40, 50, 60, 70, and 80% of the solution calcium being replaced on an equal molar basis by solution strontium. From the compositions of the equilibrating buffer solutions, ion activity products (IAPs) of the form Ca_10-nSr_n(PO₄)₆(OH)₂ (n = 0–10) were calculated in an attempt to determine the correct function governing the dissolution of the CAP preparation. The results demonstrate the following important findings: (a) at high solution strontium/calcium ratios (i.e., when 60% or more of the solution calcium was replaced by strontium), the MES profiles in all the experiments were found to be essentially superimposable when the solution IAPs were calculated using the stoichiometry of Ca₆Sr₄(PO₄)₆(OH)₂, and (b), at low solution strontium/calcium ratios (i.e., when 40% or less of the solution calcium was replaced by strontium), the stoichiometry yielding MES data superpositioning was found to be that of hydroxyapatite. When other stoichiometries were assumed, good superpositioning of the data was not possible.     

骨形态发生蛋白-2/胶原/掺锶羟基磷灰石材料修复颅骨缺损

目的 制备骨形态发生蛋白-2( BMP-2)/胶原/掺锶羟基磷灰石材料并探讨其修复大鼠颅骨缺损的可行性和有效性.方法 扫描电镜观察Ⅰ型胶原制备单纯胶原、胶原/羟基磷灰石、胶原/掺锶羟基磷灰石、BMP-2/胶原/掺锶羟基磷灰石4组骨修复材料表面结构.用BMP-2/胶原/掺锶羟基磷灰石材料浸提液进行细胞毒性试验和体外溶血试验评价其生物相容性.在大鼠头颅制备颅骨极限骨缺损模型,分别植入4种骨修复材料.术后12周CT扫描观察骨缺损修复影像学.苏木素-伊红(HE)和Masson染色观察骨缺损组织学变化,并在骨缺损及其周围新生骨部位行骨桥蛋白( OPN)和β-连环蛋白(β-catenin)免疫组织化学染色.结果 在扫描电镜下观察发现单纯的胶原材料为交织样物质结构,胶原/羟基磷灰石材料为交织晶体板状结构胶原/掺锶羟基磷灰石和BMP-2/胶原/掺锶羟基磷灰石材料晶体结构为单晶体交织状.BMP-2/胶原/掺锶羟基磷灰石材料浸提液对细胞相对增殖率(RGR)无显著影响(P＞0.05),材料的细胞毒性为1级.骨缺损CT扫描平均CT值分别为(98.5±10.2)、(208.4±19.5)、(418.4±27.1)、(476.8±30.5)hu,BMP-2/胶原/掺锶羟基磷灰石材料缺损部位CT值最高.HE和Masson染色见BMP-2/胶原/掺锶羟基磷灰石组骨质愈合完全,原骨缺损处多为红色成熟骨.胶原/掺锶羟基磷灰石组植入区内蓝色的新生骨较多.胶原/羟基磷灰石材料组,植入区在植入材料边缘新生骨形成,界限仍然清晰.单纯胶原组骨质未愈合,骨缺损处为淡蓝色条索状结构,中间未见骨形成.对比其他3组,BMP-2/胶原/掺锶羟基磷灰石组存在大量棕色的OPN和β-catenin染色阳性新生骨组织,差异有统计学意义(P＜0.05).结论 BMP-2/胶原/掺锶羟基磷灰石材料促进骨修复能力强于单纯胶原、胶原/羟基磷灰石、胶原/掺锶羟基磷灰石材料.     

89SrCl2治疗多发性骨髓瘤骨痛疗效分析

Objective: To evaluate the efficacy of 89SrCl2 in treatment of patients with multiple myeloma (MM). Methods: Thirty-three patients with phase III MM and bone pain were treated with 89SrCl2 once (4 mCi). KPS, VAS, radionuclide bone imaging, bone marrow and adverse effects were evaluated before and after treatment. Results: KPS scores raised and VAS scores decreased one month after treatment (both P<0.05). Three months after treatment, radionuclide bone imaging showed that the response rate of bone metastases was 39.4%, the stable rate was 42.4% and the non-response rate was 15.2%; there was no significant difference in the percentage of malignant plasma cells in bone marrow before and after treatment (P>0.05). No irreversible bone marrow depression was found. Conclusion: 89SrCl2 can be used to treat patients with MM as a safe and effective agent. © 2015, Journal of Practical Oncology, Editorial Board. All right reserved.     

Kinetic and pharmacological examination of stimulation-induced increases in synaptic efficacy in the chick ciliary ganglion

We have characterized the kinetic and pharmacological properties of stimulation-induced increases of synaptic efficacy in the embryonic chick ciliary ganglion. We found what appear to be four components of increased ganglionic efficacy with average time constants of decay of about 60 msec, 400 msec, 30 sec, and 200 sec. These time constants are similar to the those describing the decay of the four components of stimulation-induced increases in neurotransmitter release characterized at other synapses. These components have been termed first and second components of facilitation, augmentation, and potentiation. We found that the addition of small amounts of Ba²⁺ to the low Ca²⁺ bathing solution led to an increase in the magnitude of the augmentation-like component, whereas Sr²⁺ enhanced the magnitude and time course of the component resembling the second component of facilitation. These effects of Ba²⁺ and Sr²⁺ are similar to the effects of these same divalent cations on augmentation and the second component of facilitation, respectively, at the frog neuromuscular junction and rabbit superior cervical ganglion. Based on these similar kinetic and pharmacological properties, we conclude that the four components of stimulation-induced increases in release that have been described in other synaptic preparations also appear to be present in the chick ciliary ganglion. Published 1993 Wiley-Liss, Inc.     

Uptake and elution of radiosodium in bone powder: Comparison with47Ca and85Sr

A column constructed of defatted bone powder can discriminate between²²Na and⁵⁸Sr or⁴⁷Ca. Sodium is taken up, and eluted, from such a column at a more rapid rate than the other two isotopes. These observations make it unnecessary to assume the existence of an active process as a major explanation for the differential behaviour of Na and these multivalent cations in bonein vivo.Supported by the General Support Research Funds and the U.S. Atomic Energy Project of the University of Rochester, and assigned Report No. UR-49-1434.