Effect of cerium ion on the proliferation,differentiation and mineralization function of primary mouse osteoblasts in vitro

The effects of cerium ion(Ce3+) on the proliferation,differentiation,adipocytic transdifferentiation and mineralization function of primary mouse osteoblasts(OBs) were investigated.The results indicated that Ce3+ at all concentrations(1×10-9,1×10-8,1×10-7,1×10-6,1×10-5,and 1×10-4 mol/L) promoted the proliferation of osteoblasts(OBs).On day 1 and 3,Ce3+ promoted the differentiation of OBs at concentrations of 1×10-9,1×10-7,and 1×10-6 mol/L,but inhibited the differentiation of OBs at higher concentrations.On day 2,Ce3+ inhibited the differentiation of OBs at tested concentrations.On day 9 and 12,Ce3+ inhibited the adipocytic transdifferentiation of OBs at most concentrations.On day 15,Ce3+ promoted the adipocytic transdifferentiation of OBs at concentrations of 1×10-9,1×10-6,1×10-5,and 1×10-4 mol/L,but had no effects at other concentrations.Ce3+ inhibited the formation of mineralized matrix nodules of OBs at concentrations of 1×10-9,1×10-8 and 1×10-7 mol/L,and promoted the formation of mineralized matrix nodules of OBs at other concentrations.These findings suggested that the effects of Ce3+ on the proliferation,differentiation,adipocytic transdifferentiation and mineralization function of primary OBs depended on the concentration and culture time;moreover,they were pivotal factors for switching the biological effects of Ce3+ from toxicity to activity,from damage to protection,or from down-regulation to up-regulation.     

Effect of yttrium ion on the proliferation,differentiation and mineralization function of primary mouse osteoblasts in vitro

A series of experimental methods including MTT test,alkaline phosphatase(ALP) activity measurement,oil red O stain and measurement and mineralized function were employed to assess the effects of Y3+ on the proliferation,differentiation,adipogenic transdifferentiation and mineralization function of primary mouse osteoblasts(OBs) in vitro.The results indicated that Y3+(1×10-9,1×10-8,1×10-7,1×10-6,1×10-5,and 1×10-4 mol/L) promoted the proliferation of OBs on day 1,2 and 3.Y3+ had no effect on the differentiati...     

Effects of scandium chloride on osteogenic and adipogenic differentiation of mesenchymal stem cells

Mesenchymal stem cells(MSCs)are multi-potent cells that are able to differentiate and mature into various types of cells under a certain microenvironment for cell therapy and tissue regeneration.Scandium(Sc),an important rare earth element,recently has been intensively investigated in biomedical fields as well as industrial engineering,and chloride channels have been proven to be able to affect osteogenic differentiation.Thus,it is significant to investigate effects of ScCl₃on cell activities of MSCs.In this paper,rat bone MSCs(rBMSCs)were co-cultured with various concentrations of ScCl₃(1×10^-8,1×10^-6,and 1×10^-4mol/L)to evaluate their influence on cell proliferation as well as osteogenic and adipogenic differentiation in vitro.The results indicate that ScCl₃promotes the proliferation of rBMSCs initially,which is yet reduced upon ion accumulation.We used immunofluorescence staining,quantitative real time polymerase chain reactions,and assays measuring alkaline phosphatase activity,mineralized deposits,and intracytoplasmic lipids to reveal that rBMSCs treated with ScCl₃at concentrations of 1×10^-8-1×10^-6mol/L can enhance levels of osteogenic differentiation in a dosedependent manner and reduce adipogenic differentiation to a certain degree through Wnt/β-catenin signaling pathway.These results indicate that appropriate concentrations of ScCl₃can improve osteogenic differentiation in the lineage commitment of rBMSCs,and thus,promote bone remodeling.This study implies that ScCl₃ possesses great potentials in the treatment of bone diseases and would provide new strategy of designing composites by SiCl3 doping for biomedical applications in the future.     

Effects of Lanthanum on Formation and Bone-Resorbing Activity of Osteoclast-Like Cells

The effect of La3 on formation of osteoclast-like cells in rabbit bone marrow cells induced by 1,25-dihydroxyvitamin D3 and their bone-resorbing activity was evaluated by counting the number of tartrate resistant-acid phosphatase-positive ［TRAP( )］ multi-nucleated cells and measuring the number and surface area of bone resorption pits with photomicrography and image analysis. The formation and morphological characteristics of osteoclast-like cells and bone resorption pits were observed under a phase contrast inverted microscope. La3 promotes the formation of osteoclast-like cells at the concentration of 1.00×10-8mol·L-1 compared with the control group(P<0.01), whereas no significant change in cell number is observed at higher concentrations(1.00×10-5, 1.00×10-6 and 1.00×10-7 mol·L-1)(P>0.05). La3 at the concentration of 1.00×10-8mol·L-1 also increases the number and surface area of the resorption pits(P<0.01), but inhibits the bone-resorbing activity dose-dependently(P<0.01)at higher concentrations(1.00×10-5, 1.00×10-6 and 1.00×10-7 mol·L-1). These findings suggest that La3 may promote or inhibit the formation and bone-resorbing activity of osteoclast-like cells depending on its concentration.     

Effects of gadolinium on proliferation, differentiation and calcification of primary mouse osteoblasts in vitro

To evaluate the effects of Gd on proliferation, differentiation and mineralization function of primary osteoblasts (OBs) in vitro, we tested cell viability by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay, cell differentiation by alkaline phosphatase (ALP) activity assay, synthesis of type ? collagen, and oil red O and alizarin red S (ARS) stain assays. The results indicated that effects of Gd on the proliferation, osteogenic differentiation, mineralization function and adipocytic transdifferentiation of primary OBs de-pended on concentration and incubation time, but were not dose-dependent. It was suggested that the effect of Gd on bone metabolism was complicated, and concentration and culture time were key factors for switching the biological effects of Gd from damage to protection.     

Effects of Lanthanum on Bone Resorbing Activity of Rabbit Mature Osteoclasts Co-Cultured with Osteoblasts

The effects of lanthanum (Ⅲ) on the bone resorbing activity of rabbit mature osteoclasts (OCs) in the presence of osteoblasts (OBs) were studied in vitro by measuring the number and area of absorption pits. La(Ⅲ) at concentrations ranging from 1.00×10-5 to 1.00×10-8 mol·L-1 show no effect on mature OC number (P＞0.05). In the OC-OB co-culture systems without La(Ⅲ), osteoblasts alone did not influence the pit number and area whether the two kinds of cells were in contact or not (P＞0.05). Under the OC-OB not-in-contact condition, the effect of La(Ⅲ) on the bone-resorbing activity of OCs was similar to that of La(Ⅲ) in the absence of OBs (P＞0.05). However, while OCs were in direct contact with OBs, the inhibitory effects of La(Ⅲ) on OCs' bone-resorbing activity decreased at the concentrations of 1.00×10-5, 1.00×10-6 and 1.00×10-7 mol·L-1, and the promotion effects increased at 1.00×10-8 mol·L-1 (P＜0.05). The results suggest that direct cell-cell contact between OC and OB be essential for OBs to play their role in regulating the response of OCs to La(Ⅲ).     

Induction of osteoblast differentiation in human adipose derived stem cells by lanthanum ions

Adipose derived stem cells represent a readily available source of adult stem cells for various biomedical applications. In this study, the proliferation and osteogenic differentiation potential of lanthanum nitrate（La3＋） on human adipose derived mesenchymal stem cells（hADSCs） were investigated for the first time and compared with that of dexamethasone（Dex）. Our results provided evidence that La3＋ at 50 μmol/L concentration promoted proliferation of hADSCs upto 2.4 fold when treated for 21 d in DMEM medium. Treatment of hADSCs with La3＋ containing osteogenic induction medium（α-MEM with ascorbic acid and β-glycerophosphate） for 7 d resulted in higher calcium deposition than that in the presence of Dex（0.1 μmol/L） as shown by Alizarin red S and von Kossa staining. Scanning electron micrographs also showed more extracellular matrix mineralization in the presence of La3＋. After 7 d of treatment with La3＋（10 μmol/L） the expression of RunX2, osteopontin（OP） and osteocalcin（OC） increased 3.4, 5.5 and 2.7 fold respectively. Our results provided evidence that in the presence of La3＋ osteogenic differentiation occurred earlier than that in the presence of Dex.     

Effect of Lanthanum(Ⅲ) on Cytosolic Free Calcium in Isolated Rabbit Mature Osteoclasts

The effect of lanthanum(Ⅲ) (La3 ) on cytosolic free calcium ([Ca2 ]i) in isolated rabbit mature osteoclasts was studied with the employment of fluo-3/AM as an intracellular calcium-sensitive fluorescent probe by using a confocal laser scanning microscope. La3 does not alter basal [Ca2 ]i levels and cell spread area at the concentration of 1.00×10-8 mol·L-1. However, La3 at higher concentrations ( 1.00×10-5 and 1.00×10-7 mol·L-1) decreases [Ca2 ]i levels and cell spread area, and greater decreases are observed for the higher concentrations of La3 . Since [Ca2 ]i affects cytoskeleton and the adhesion properties of osteoclasts, our results seem to suggest that La3 inhibit bone resorption by decreasing [Ca2 ]i in rabbit mature osteoclasts.     

Ytterbium ion promotes apoptosis of primary mouse bone marrow stromal cells

One of the main target organs for the lanthanides(Ln) is bone. Previous studies revealed that ytterbium(Yb) produced damage to the skeletal system in vivo. But the effects of Yb3+ on bone marrow stromal cells(BMSCs) in vitro had not been reported. In this paper, cell viability, apoptosis, mitochondrial membrane potential(MMP), reactive oxygen species(ROS) and lactate dehydrogenase(LDH) were measured in order to study the effects of Yb3+ on BMSCs. The results indicated that Yb3+ displayed a slight positive effect on the BMSCs viability at concentrations of 1×10–6, 1×10–5, and 1×10–4 mol/L, but turned to decrease the viability of BMSCs at the highest concentration of 1×10–3 mol/L for 24, 48 and 72 h. Yb3+ at 1×10–3 mol/L promoted apoptosis of BMSCs, increased the levels of ROS and LDH, and decreased MMP in BMSCs. It suggested that the precipitate of Yb PO4 might decrease the viability of BMSCs. Yb3+ induced the apoptosis of BMSCs via mitochondrial pathway. The results might be useful for more rational application of Yb-based compounds in the future.     

1,25-Dihydroxy vitamin D3 inhibits adipocyte differentiation and gene expression in murine bone marrow stromal cell clones and primary cultures

Bone marrow stromal stem cells differentiate into adipocytes and osteoblasts. These two lineages are thought to be reciprocally related, in part due to the observation that the osteoblast-inducing factor, 1,25 dihydroxy vitamin D3 [1,25(OH)2D3], inhibited adipogenesis of rat femoral-derived stromal cell cultures. However, the literature is divided concerning the adipogenic effects of this steroid hormone. This work examined the effect of 1,25(OH)2D3 (10(-12)-10(-8) M) on murine femoral-derived bone marrow stromal cell differentiation in response to adipogenic agonists employing two different classes of nuclear hormone receptors: the glucocorticoid receptor (hydrocortisone) or peroxisome proliferator-activated receptors (thiazolidinediones). Experiments used the multipotent murine bone marrow stromal cell line, BMS2, and its subclones, as well as primary-derived murine bone marrow stromal cell cultures. In all systems examined, 1,25(OH)2D3 blocked adipogenesis induced by hydrocortisone, methylisobutylxanthine, and indomethacin based on flow cytometric analysis of lipid accumulation. This correlated with reduced messenger RNA levels of the late adipocyte gene markers, aP2 and adipsin. In the BMS2 subclone no. 24, the 1,25(OH)2D3 actions were concentration dependent. Whereas 1,25(OH)2D3 partially inhibited thiazolidinedione-induced adipogenesis in the parental BMS2 cell line, it had minimal effect on the thiazolidinedione-induced differentiation of the BMS2 subclone and primary cultures. These findings indicate that 1,25(OH)2D3, at nanomolar concentrations, completely inhibits murine bone marrow stromal cell differentiation in response to glucocorticoid-based adipogenic agonists but is a less effective adipogenic antagonist following induction with thiazolidinediones. This work supports the conclusion that 1,25(OH)2D3 inhibits murine femoral-derived bone marrow stromal cell adipogenesis.     

六氰合铁酸铁/全氟磺酸 聚四氟乙烯共聚物复合膜修饰玻碳电极差分脉冲伏安法测定铅和镉

利用电聚合的方法将普鲁士蓝修饰到玻碳电极表面,然后修饰上全氟磺酸 聚四氟乙烯共聚物(Nafion)膜制成修饰电极。利用差分脉冲伏安法（DPV）对Pb2+和Cd2+在该修饰电极上的电化学行为进行了研究,建立了差分脉冲伏安法灵敏测定Cd2+和Pb2+的新方法。对富集电位、富集时间以及Nafion用量等实验条件进行了优化。在01 mol/L pH 45的NaAc HAc缓冲液中,在-11 V处搅拌富集450 s,用DPV分别测定-048 V和-073 V处的氧化峰电流。溶出峰电流与Pb2+和Cd2+的浓度分别在5×10-8~5×10-5 mol/L和2×10-8~2×10-5 mol/L范围内呈良好的线性关系,相关系数分别为0995和0992。检出限分别为5×10-9 mol/L (Pb2+)和2×10-9 mol/L(Cd2+) (S/N=3)。方法用于水样中Cd2+和Pb2+的测定,测定值与原子吸收光谱法的结果相一致,相对标准偏差为21%~38%。     

4-(3-吡啶基)-2-巯基咪唑修饰碳糊电极阳极溶出伏安法测定痕量银

报道了采用化合物4-(3-吡啶基)-2-巯基咪唑(PMI)修饰碳糊电极测定痕量银的阳极溶出伏安法。在0.1 mol/L的HNO3中,Ag+可以富集于PMI修饰电极表面,将介质交换至含I-的0.02 mol/L硫酸溶液中,-0.20 V还原30 s后再进行阳极溶出伏安测定,可以获得灵敏的银阳极溶出峰。一次导数峰电流与Ag+在8.0×10-10~4.0×10-6mol/L浓度范围内呈线性关系,检出限可达5.0×10-10mol/L(S/N=3)。采用本法不经过预分离,对成分复杂的定影液废液和锌合金等样品进行了直接测定,测定的回收率为92%~105%。     

Electrochemical Preparation of La—Fe Alloy Films in Dimethylsulfoxide（DMSO）

Ｒａｒｅｅａｒｔｈｓａｎｄｔｈｅｉｒａｌｌｏｙｓｈａｖｅｓｐｅｃｉｆｉｃｐｒｏｐｅｒｔｉｅｓ ,ｓｕｃｈａｓｍａｇｎｅｔｉｃ ,ｏｐｔｉｃａｌ,ｅｌｅｃｔｒｉｃａｎｄｈｙｄｒｏｇｅｎｓｔｏｒａｇｅ .Ｔｈｅｙｈａｖｅｂｅｅｎｗｉｄｅｌｙａｐｐｌｉｅｄｔｏｖａｒｉｏｕｓｆｕｎｃｔｉｏｎａｌｍａｔｅｒｉａｌｓ .ＴｈｅＬａ Ｆｅａｌｌｏｙｓｈａｖｅｂｅｅｎａｐｐｌｉｅｄａｓｍａｇｎｅｔｉｃｍａｔｅｒｉａｌｓ .Ｓｉｎｃｅｒａｒｅｅａｒｔｈｅｌｅｍｅｎｔｓａｒｅｖｅｒｙａｃｔｉｖｅ,ｉｔｉｓｖｅｒｙｄｉｆｆｉｃｕ…     

离子交换分离富集极谱法连续测定金、铂、铱、铑、钌

研究了在同一份试液中极谱法连续测定Au、Pt、Ir、Rh、Ru的体系。首先在1mol/L的氢氧化钠溶液中,于原点电位-0.20V处扫描作Au的峰电流-质量浓度曲线;然后,改变溶液pH值,在0.75mol/L硫酸-1.5%氯化铵-1.5×10-3mol/L六次甲基四胺-0.003%硫酸肼体系中,于原点电位-0.78V处扫描作Pt、Ir、Rh的峰电流-质量浓度曲线;最后,加入2.25mol/L硫酸-4%氯化铵-2.5×10-4mol/L硫脲测定Ru。在选定的实验条件下得到令人满意的分析结果,线性范围分别为:0.1～1000μg/mL(Au);8×10-5～6.4×10-3μg/mL(Pt、Ir);1.6×10-5～1.28×10-3μg/mL(Rh);1.14×10-4～3.42×10-3μg/mL(Ru)。实际样品通过阴离子交换树脂分离富集后进行分析,回收率在93%～106%之间。