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Parathyroid hormone-related peptide (PTHrP) and parathyroid hormone (PTH)/PTHrP-receptor, PTH/PTHrP-R, are frequently expressed in mammary carcinomas as well as in bone cells. In this study we compared the ligand binding characteristics of the PTH/PTHrP-R in SaOS-2 human osteosarcoma cells with those in MCF7 breast cancer cells. We used both Scatchard analysis of saturation kinetics for iodinated ligand and the level of expressed receptor protein by visualising the single radio-labelled receptor-ligand complex from isolated membrane preparations from the two cell lines. In MCF7 cells, ligand binding, (receptor number) was increased by prior exposure of the cultured cells to epidermal growth factor (EGF), estradiol (E2), or dexamethasone (DEX), and decreased following calcitriol (1,25 DHCC). In contrast in the SaOS-2 cells, PTH/PTHrP-R number was increased by exposure to E2 and 1,25DHCC and decreased by DEX while EGF had no effect. These data were confirmed when the PTH/PTHrP-R was cross linked with (125)I-PTHrP-1-34(Tyr), and extended by visualising the intensity of the isolated radiolabelled receptor complex by autoradiography following SDS-PAGE at several time points during the treatment. 相似文献
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De Pedro JA Pérez-Caballer AJ Dominguez J Collía F Blanco J Salvado M 《Bioelectromagnetics》2005,26(1):20-27
An experimental study was carried out in rats with the purpose of demonstrating the capacity of pulsed electromagnetic fields (PEMFs) to stimulate regeneration of the peripheral nervous system (PNS). Wistar and Brown Norway (BN) rats were used. Direct sciatic nerve anastomoses were performed after section or allograft interposition. Treatment groups then received 4 weeks of PEMFs. Control groups received no stimulation. The evaluation of the results was carried out by quantitative morphometric analysis, demonstrating a statistically significant increase in regeneration indices (P < 0.05) in the stimulated groups (9000 +/- 5000 and 4000 +/- 6000) compared to the non-stimulated groups (2000 +/- 4000 and 700 +/- 200). An increase of NAD specific isocitrate dehydrogenase (IDH) activity was found along with an increase in the activity of acetyl cholinesterase at the motor plate. The present study might lead to the search for new alternatives in the stimulation of axonal regenerative processes in the PNS and other possible clinical applications. 相似文献
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The aim of the present study was to compare the classical parathyroid hormone/parathyroid hormone-related peptide (PTH/PTHrP) receptors in MCF7 breast cancer cells with SaOS-2 osteosarcoma cell line. Quantitative binding showed that (125)I-PTHrP-1-34(Tyr) binds with a single binding site in both cells. However (125)I-PTHrP-1-34(Tyr) has higher affinity binding in MCF7 (K(D) = 1.88 +/- 0.08 nM) than in SaOS-2 cells (K(D) = 4.4 +/- 0.185 nM). The competitive binding using 3.3 nM (125)I-PTHrP-1-34(Tyr) with increasing amounts (0.33-33 nM) of unlabelled human PTHrP-1-34, PTHrP-7-34, PTHrP-1-86 His(5)-PTHrP-1-36, His(5)-Phe(23)-PTHrP-1-36 or PTH-1-34 revealed different displacements. In SaOS-2 the PTHrP-7-34 and PTHrP-1-86 caused similar displacement compared with 73% by PTH-1-34 and 70% by PTHrP-1-34. However, in MCF7, PTHrP-7-34, PTHrP-1-86 and PTH-1-34 displaced by 54%, 72% and 67%, respectively, compared to 87% by PTHrP-1-34. The His(5)-Phe(23)-PTHrP-1-36 caused an increase in the K(D) from 2.0 +/- 0.03 nM to 2.75 +/- 0.045 nM in MCF7 cells, but had no significant effect in SaOS-2 cells. The PTH/PTHrP receptor in both cell lines revealed a single 85 KDa band with different intensity. Our results suggest that the PTH/PTHrP receptor in MCF7 cells has higher binding affinity for PTHrP than PTH compared to the receptor in SaOS-2 cells. 相似文献
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Pulsing electromagnetic field (PEMF) therapy may be a viable form of complementary and alternative medicine. Clinical applications
include the treatment of fractures, wounds, and heart disease. More recent applications involve treatment of recurrent headache
disorders. This paper reviews available studies investigating PEMF for headache management. Possible mechanisms for effects
(neurochemical, electrophysical, and cardiovascular) are discussed. The available data suggest that PEMF treatment for headache
merits further study. Suggestions for future research are provided. 相似文献
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脉冲电磁场(pulse electromagnetic fields, PEMFs)能够促进大鼠成骨细胞（rat osteoblast cells, ROB）成熟矿化,但是其作用机制并不明确。本实验主要研究PEMFs促进大鼠成骨细胞成熟矿化与NO/cGMP信号途径的关系,进而阐明PEMFs促进成骨细胞成熟矿化的机理。首先将成骨细胞经50Hz、0.6mT脉冲电磁场作用不同时间后,检测细胞培养液中一氧化氮(Nitric Oxide, NO)和细胞内3?-5?-环鸟苷一磷酸(3?-5?-cyclic-GMP, cGMP)的含量,以探明电磁场是否影响NO和cGMP的合成;其次,提取总蛋白,应用蛋白质印迹检测细胞内eNOS、iNOS和PKG-1的蛋白表达量;最后,利用NOS的阻断剂L-NAME抑制NO信号通路后,检测成骨性相关指标,包括碱性磷酸酶（ALP）活性、钙化结节数量、成骨性基因Bmp-2、Collagen-1、Osterix及破骨细胞调节因子Rankl基因的表达量。结果发现经PEMFs处理后,NO含量及cGMP含量均有明显升高;细胞内eNOS、iNOS和PKG-1蛋白表达量较空白对照组均有显著升高,说明PEMFs能够激活NO/cGMP信号途径。且经PEMFs处理的成骨细胞,ALP活性升高,BMP-2、Collagen-1和Osterix基因表达量显著增加,Rankl基因表达量下降,成骨细胞形成钙化结节的能力增强,当加入L-NAME,PEMFs引起的ALP活性增加、成骨性基因表达升高和钙化结节形成能力增强的趋势均被显著抑制。上述结果表明,经PEMFs处理成骨细胞成熟矿化过程中 NO/cGMP信号通路被激活;如该通路被抑制,则电磁场促成骨作用被抵消。说明脉冲电磁场促进成骨细胞成熟矿化依赖于NO/cGMP信号通路。 相似文献
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A 1984 study determined the effect of a 72 Hz pulsating electromagnetic field (PEMF) on bone density of the radii of post-menopausal (osteoporosis-prone) women, during and after treatment of 10 h daily for 12 weeks. Bone mineral densities of the treated radii increased significantly in the immediate area of the field during the exposure period and decreased during the following 36 weeks. Bone density determination of the radii of these women, remeasured after eight years, suggests no long-term changes. The bone density-enhancing effect of PEMFs should be further studied, alone and in combination with exercise and pharmacologic agents such as the bisphosphonates and hormones, as prophylaxis in the osteoporosis-prone postmenopausal woman and as a possible block to the demineralization effect of microgravity. Bioelectromagnetics 19:75–78, 1998. © 1998 Wiley-Liss, Inc. 相似文献
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Biosilica‐loaded poly(ϵ‐caprolactone) nanofibers mats provide a morphogenetically active surface scaffold for the growth and mineralization of the osteoclast‐related SaOS‐2 cells 
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下载免费PDF全文 Werner E.G. Müller Emad Tolba Heinz C. Schröder Bärbel Diehl‐Seifert Thorben Link Xiaohong Wang 《Biotechnology journal》2014,9(10):1312-1321
Bioprinting/3D cell printing procedures for the preparation of scaffolds/implants have the potential to revolutionize regenerative medicine. Besides biocompatibility and biodegradability, the hardness of the scaffold material is of critical importance to allow sufficient mechanical protection and, to the same extent, allow migration, cell–cell, and cell–substrate contact formation of the matrix‐embedded cells. In the present study, we present a strategy to encase a bioprinted, cell‐containing, and soft scaffold with an electrospun mat. The electrospun poly(?‐caprolactone) (PCL) nanofibers mats, containing tetraethyl orthosilicate (TEOS), were subsequently incubated with silicatein. Silicatein synthesizes polymeric biosilica by polycondensation of ortho‐silicate that is formed from prehydrolyzed TEOS. Biosilica provides a morphogenetically active matrix for the growth and mineralization of osteoblast‐related SaOS‐2 cells in vitro. Analysis of the microstructure of the 300–700 nm thick PCL/TEOS nanofibers, incubated with silicatein and prehydrolyzed TEOS, displayed biosilica deposits on the mats formed by the nanofibers. We conclude and propose that electrospun PCL nanofibers mats, coated with biosilica, may represent a morphogenetically active and protective cover for bioprinted cell/tissue‐like units with a suitable mechanical stability, even if the cells are embedded in a softer matrix. 相似文献
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Hui‐Fang Liu Lin Yang Hong‐Chen He Jun Zhou Ying Liu Chun‐Yan Wang Yuan‐Chao Wu Cheng‐Qi He 《Bioelectromagnetics》2013,34(4):323-332
A randomized, active‐controlled clinical trial was conducted to examine the effect of pulsed electromagnetic fields (PEMFs) on women with postmenopausal osteoporosis (PMO) in southwest China. Forty‐four participants were randomly assigned to receive alendronate or one course of PEMFs treatment. The primary endpoint was the mean percentage change in bone mineral density of the lumbar spine (BMDL), and secondary endpoints were the mean percentage changes in left proximal femur bone mineral density (BMDF), serum 25OH vitamin D3 (25(OH)D) concentrations, total lower‐extremity manual muscle test (LE MMT) score, and Berg Balance Scale (BBS) score. The BMDL, BMDF, total LE MMT score and BBS score were recorded at baseline, 5, 12, and 24 weeks. Serum concentrations of 25(OH)D were measured at baseline and 5 weeks. Using a mixed linear model, there was no significant treatment difference between the two groups in the BMDL, BMDF, total LE MMT score, and BBS score (P ≥ 0.05). For 25(OH)D concentrations, the effects were also comparable between the two groups (P ≥ 0.05) with the Mann–Whitney's U‐test. These results suggested that a course of PEMFs treatment with specific parameters was as effective as alendronate in treating PMO within 24 weeks. Bioelectromagnetics 34:323–332, 2013. © 2012 Wiley Periodicals, Inc. 相似文献
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This study was a meta-analysis to examine whether electrical stimulation has a specific effect on spinal fusion. Little evidence exists on the efficacy of electrical stimulation for improving fusion rate of spinal fusion surgery. Using MEDLINE (1966-2000) and EMBASE (1985-1999), a search for articles was carried out using the Medical Subject Headings: (1) electric stimulation or electromagnetic fields, (2) spinal fusion, (3) controlled or clinical trial, and (4) human. Data were extracted from all the hit articles and additionally collected from appropriate journal lists. A total of five randomized controlled trials (RCT) on bones assessing healing of spinal fusion were identified and scored on methodological quality. All the identified studies reported positive findings, but the quality score of each trial showed wide flaws. Because of relatively homogenous subjects who had spine fusion and radiographic assessment from these studies, pooling of the data was able to be performed. Excluding one trial with the lowest score, the combined results of four trials, whose major endpoints were the success rate of the fusion, revealed a statistically significant effect of electrical stimulation with various techniques, but the selected trials still showed wide variation in view of stimulation modalities and treatment protocol. The pooled result of the studies in this review revealed the efficacy of electrical stimulation based on proved methodological quality. As problems on therapeutic modality and protocol remain, there is a further need for improvement in design to constitute acceptable proof and to establish treatment programs that better demonstrate electrical stimulation effects on spinal fusion. 相似文献
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Cyril Thouverey Agnieszka Strzelecka‐Kiliszek Marcin Balcerzak René Buchet Slawomir Pikula 《Journal of cellular biochemistry》2009,106(1):127-138
In bone, mineralization is tightly regulated by osteoblasts and hypertrophic chondrocytes which release matrix vesicles (MVs) and control extracellular ionic conditions and matrix composition. MVs are the initial sites of hydroxyapatite (HA) mineral formation. Despite growing knowledge about their morphology and function, their biogenesis is not well understood. The purpose of this work was to determine the source of MVs in osteoblast lineage, Saos‐2 cells, and to check whether MVs originated from microvilli. Microvilli were isolated from the apical plasma membrane of Saos‐2 cells. Their morphology, structure, and function were compared with those of MVs. The role of actin network in MV release was investigated by using microfilament perturbing drugs. When examined by electron microscopy MVs and microvillar vesicles were found to exhibit similar morphology with trilaminar membranes and diameters in the same range. Both types of vesicles were able to induce HA formation. Their electrophoretic profiles displayed analogous enrichment in alkaline phosphatase, Na+/K+ ATPase, and annexins A2 and A6. MVs and microvillar vesicles exhibited almost the same lipid composition with a higher content of cholesterol, sphingomyelin, and phosphatidylserine as compared to plasma membrane. Finally, cytochalasin D, which inhibits actin polymerization, was found to stimulate release of MVs. Our findings were consistent with the hypothesis that MVs originated from cell microvilli and that actin filament disassembly was involved in their biogenesis. J. Cell. Biochem. 106: 127–138, 2009. © 2008 Wiley‐Liss, Inc. 相似文献
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研究正弦波电磁场(SEMF)促进成骨细胞成熟矿化是否与一氧化氮(NO)信号通路相关.首先检测成骨细胞经正弦电磁场作用0h、0.5h、1h、1.5h、2h、2.5h、3h、3.5h和4h后一氧化氮合酶(NOS)的活性,以探明电磁场是否影响NO的合成;其次,在细胞培养液中加入NOS的阻断剂L-NAME以阻断NO信号通路,观察电磁场促进骨形成作用是否受到影响.结果发现,经正弦波电磁场处理后,NOS活性升高,在0.5h达到峰值,与空白对照组差异极显著(P<0.01),Osterix基因的表达量、碱性磷酸酶活性和钙化结节数等均显著高于对照组.L-NAME组各项指标均低于空白对照组,SEMF+L-NAME组则略高于空白对照组而低于SEMF组.以上结果表明SEMF促进成骨细胞成熟矿化过程中NO信号通路被激活,如该通路被抑制,则SEMF的促成骨作用被抵消. 相似文献
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Luke A. Smith MSc Jaedon D. Bem MSc Xiaojing Lv PhD Antonio Lauto PhD Ashour Sliow PhD Zhiyuan Ma MD David A. Mahns PhD Carolyn Berryman PhD Mark R. Hutchinson PhD Christophe Fumeaux PhD Giuseppe C. Tettamanzi PhD 《Bioelectromagnetics》2023,44(7-8):181-191
Electric-field stimulation of neuronal activity can be used to improve the speed of regeneration for severed and damaged nerves. Most techniques, however, require invasive electronic circuitry which can be uncomfortable for the patient and can damage surrounding tissue. A recently suggested technique uses a graft-antenna—a metal ring wrapped around the damaged nerve—powered by an external magnetic stimulation device. This technique requires no electrodes and internal circuitry with leads across the skin boundary or internal power, since all power is provided wirelessly. This paper examines the microscopic basic mechanisms that allow the magnetic stimulation device to cause neural activation via the graft-antenna. A computational model of the system was created and used to find that under magnetic stimulation, diverging electric fields appear at the metal ring's edges. If the magnetic stimulation is sufficient, the gradients of these fields can trigger neural activation in the nerve. In-vivo measurements were also performed on rat sciatic nerves to support the modeling finding that direct contact between the antenna and the nerve ensures neural activation given sufficient magnetic stimulation. Simulations also showed that the presence of a thin gap between the graft-antenna and the nerve does not preclude neural activation but does reduce its efficacy. 相似文献
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Butler JJ Mader JS Watson CL Zhang H Blay J Hoskin DW 《Journal of cellular biochemistry》2003,89(5):975-991
Adenosine is an immunosuppressive molecule that is associated with the microenvironment of solid tumors. Mouse T cells activated with anti-CD3 antibody in the presence of adenosine with or without coformycin (to prevent adenosine breakdown by adenosine deaminase) exhibited decreased tyrosine phosphorylation of some intracellular proteins and were inhibited in their ability to proliferate and synthesize interleukin (IL)-2. In addition, adenosine interfered with activation-induced expression of the co-stimulatory molecules CD2 and CD28. Activation-induced CD2 and CD28 expression was also diminished when T cells were activated in the presence of anti-IL-2 and anti-CD25 antibodies to neutralize IL-2 bioactivity. Collectively, these data suggest that CD2 and CD28 up-regulation following T cell activation is IL-2-dependent; and that adenosine inhibits activation-induced T cell expression of CD2 and CD28 by interfering with IL-2-dependent signaling. The inhibitory effect of adenosine on activation-induced CD2 and CD28 expression could not be attributed to cyclic AMP (cAMP) accumulation resulting from the stimulation of adenylyl cyclase-coupled adenosine receptors, even though cAMP at concentrations much higher than those generated following adenosine stimulation was inhibitory for both CD2 and CD28 expression. We conclude that adenosine interferes with IL-2-dependent T cell expression of co-stimulatory molecules via a mechanism that does not involve the accumulation of intracellular cAMP. 相似文献
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Chaoxu Liu Jizhe Yu Yong Yang Xiangyu Tang Dongming Zhao Wenchun Zhao Hua Wu 《Bioelectromagnetics》2013,34(6):453-464
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Long-term treatment with heparin has been associated with an increased risk of osteoporosis. Given the importance of heparan sulfate proteoglycans for bone metabolism, it can be anticipated that heparin due to its structural similarity with heparan sulfate chains somehow interferes with the biological activities of these cell surface- and extracellular matrix-associated molecules. Initially in order to study the effect(s) of heparin on osteoblasts that possibly contribute to the development of heparin-induced osteoporosis, we treated osteoblast-like Saos-2 cells in monolayer culture for different periods of time with different concentrations of heparin. None of the heparin concentrations tested led to an inhibition of osteoblast proliferation during the early proliferative phase. After longer incubation times, however, cultures treated with higher concentrations of heparin (>/=5 microg/ml) exhibited a reduction in cell number as well as an inhibition of matrix deposition and mineralization. These effects could not be observed with lower heparin concentrations. On the contrary, low concentrations of heparin (5-500 ng/ml) even promoted matrix deposition and its subsequent mineralization. Apparently, heparin has a biphasic effect on osteoblast-like Saos-2 cells, being inhibitory at high concentrations but stimulatory at low concentrations. These results imply that heparin at concentrations well below those used for antithrombotic therapy might eventually turn out to be beneficial for bone formation. 相似文献
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Jiahui Sun Rachel Lai‐Chu Kwan Yongping Zheng Gladys Lai‐Ying Cheing 《Bioelectromagnetics》2016,37(5):290-297
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Anabolic hormones, mechanical loading, and the obese protein leptin play separate roles in maintaining bone mass. We have previously shown that leptin, as well as its receptor, are expressed by normal human osteoblasts. Consequently, we have investigated how leptin affects proliferation, differentiation, and apoptosis of human osteoblasts. Iliac crest osteoblasts, incubated with either leptin (100 ng/ml), calcitriol (1,25(OH)(2)D(3); 10(-9) M) or 1-84 human parathyroid hormone (PTH; 10(-8) M), were cultured for 35 consecutive days and assayed for expression of various differentiation-related marker genes (as estimated by RT-PCR), de novo collagen synthesis, proliferation, in vitro mineralization, and osteoclast signaling. The effects of leptin on protection against retinoic acid (RA; 10(-7) M) induced apoptosis, as well as transition into preosteocytes, were also tested. Leptin exposure enhanced cell proliferation and collagen synthesis over both control condition and PTH exposure. Leptin inhibited in vitro calcified nodule production after 1-2 weeks in culture, however, subsequent to 4-5 weeks, leptin significantly stimulated mineralization. The mineralization profile throughout the entire incubation period was almost undistinguishable from the one induced by PTH. In comparison, 1,25(OH)(2)D(3) generally reduced proliferation and collagen production rates, whereas mineralization was markedly enhanced. Leptin exposure (at 2 and 5 weeks) significantly enhanced the expression of TGFbeta, IGF-I, collagen-Ialpha, ALP, and osteocalcin mRNA. Leptin also protected against RA-induced apoptosis, as estimated by soluble DNA fractions and DNA laddering patterns subsequent to 10 days of culture. The expression profiles of Bax-alpha and Bcl-2 mRNAs indicated that leptin per se significantly protected against apoptosis throughout the entire incubation period. Furthermore, the osteoblast marker OSF-2 was diminished, whereas the CD44 osteocyte marker gene expression was stimulated, indicating a transition into preosteocytes. In terms of osteoclastic signaling, leptin significantly augmented the mRNA levels of both interleukin-6 (IL-6) and osteoprotegerin (OPG). In summary, continuous leptin exposure of iliac crest osteoblasts, promotes collagen synthesis, cell differentiation and in vitro mineralization, as well as cell survival and transition into preosteocytes. Leptin may also facilitate osteoblastic signaling to the osteoclast. 相似文献