scholarly journals Velocity dispersion and backscatter in marrow-filled and water-filled trabecular bone samples in vitro

2018 ◽  
Vol 144 (5) ◽  
pp. EL386-EL391 ◽  
Author(s):  
Kang Il Lee
1992 ◽  
Vol 50 (4) ◽  
pp. 336-341 ◽  
Author(s):  
Dominique Egrise ◽  
Dominique Martin ◽  
Pierre Neve ◽  
Anne Vienne ◽  
Michel Verhas ◽  
...  

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Xianling Feng ◽  
Xinxin Yue ◽  
Mao Niu

Objectives. The present study intended to further verify that simvastatin-loaded nanomicelles (SVNs) enhanced the role of simvastatin (SV) in promoting osteoblast differentiation in vitro and to evaluate the effect of SVNs on bone defect repair in vivo. Methods. SVNs were synthesized by dialysis. MG63 cells were subjected to intervention with 0.25 μmol/l of SVNs and SV. A 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay kit and flow cytometry were used to determine cell proliferation activity, cell cycle distribution, and apoptosis. The osteoblastic differentiation of MG 63 cells was evaluated by measuring alkaline phosphatase (ALP) activity, ALP staining, and the expression levels of the osterix (Osx) and osteocalcin (OC) proteins. In addition, 0.5 mg of SVNs or SV was applied to the skull defect area of rabbits. Micro-CT, hematoxylin and eosin (HE) staining, and Masson’s trichrome staining were used for qualitative and quantitative evaluation of new bone in three dimensions and two dimensions. Results. The SVNs had a mean diameter of 38.97 nm. The encapsulation and drug-loading efficiencies were 54.57 ± 3.15 % and 10.91 ± 0.63 % , respectively. In vitro, SVNs and SV can inhibit the proliferation activity and promote osteogenic differentiation of MG63 cells by arresting MG63 cells at the G0/G1 phase without increasing the apoptosis rate. In vivo quantitative results showed that the bone mineral density (BMD), bone volume (BV)/total volume (TV) ratio, and trabecular number (Tb.N) in the gelatin sponge with SVNs (SVNs-GS) group and gelatin sponge with SV (SV-GS) group were 362.1%, 292.0%; 181.3%, 158.0%; and 215.2%, 181.8% of those in the blank control (BC) group, respectively. Histological results identified the new bone tissue in each group as irregular fibrous bone, and the arrangement of trabecular bone was disordered. There were significantly more osteoblasts and new capillaries around the trabecular bone in the SVNs-GS group and SV-GS group than in both the BC and drug-free nanomicelle (DFNs) groups. Both in vitro and in vivo, SVNs exhibited greater osteogenic efficacy than SV. Conclusion. SVNs significantly improved the osteogenic efficacy of SV.


Author(s):  
Marcelo G.P. Cavalcanti ◽  
Axel Ruprecht ◽  
William T. Johnson ◽  
Thomas E. Southard ◽  
Jane Jakobsen

2008 ◽  
Vol 123 (5) ◽  
pp. 3512-3512 ◽  
Author(s):  
Guillaume Haiat ◽  
Alain Lhémery ◽  
Frederic Padilla ◽  
Pascal Laugier ◽  
Salah Naili

2000 ◽  
Vol 123 (2) ◽  
pp. 176-183 ◽  
Author(s):  
W. Pistoia ◽  
B. van Rietbergen ◽  
A. Laib ◽  
P. Ru¨egsegger

Micro-finite element (μFE) models based on high-resolution images have enabled the calculation of elastic properties of trabecular bone in vitro. Recently, techniques have been developed to image trabecular bone structure in vivo, albeit at a lesser resolution. The present work studies the usefulness of such in-vivo images for μFE analyses, by comparing their μFE results to those of models based on high-resolution micro-CT (μCT) images. Fifteen specimens obtained from human femoral heads were imaged first with a 3D-pQCT scanner at 165 μm resolution and a second time with a μCT scanner at 56 μm resolution. A third set of images with a resolution of 165 μm was created by downscaling the μCT measurements. The μFE models were created directly from these images. Orthotropic elastic properties and the average tissue von Mises stress of the specimens were calculated from six FE-analyses per specimen. The results of the 165 μm models were compared to those of the 56 μm model, which was taken as the reference model. The results calculated from the pQCT-based models, correlated excellent with those calculated from the reference model for both moduli R2>0.95 and for the average tissue von Mises stress R2>0.83. Results calculated from the downscaled micro-CT models correlated even better with those of the reference models (R2>0.99 for the moduli and R2>0.96 for the average von Mises stress). In the case of the 3D-pQCT based models, however, the slopes of the regression lines were less than one and had to be corrected. The prediction of the Poisson’s ratios was less accurate (R2>0.45 and R2>0.67) for the models based on 3D-pQCT and downscaled μCT images respectively). The fact that the results from the downscaled and original μCT images were nearly identical indicates that the need for a correction in the case of the 3D-pQCT measurements was not due to the voxel size of the images but due to a higher noise level and a lower contrast in these images, in combination with the application of a filtering procedure at 165 micron images. In summary: the results of μFE models based on in-vivo images of the 3D-pQCT can closely resemble those obtained from μFE models based on higher resolution μCT system.


Bone ◽  
2012 ◽  
Vol 50 ◽  
pp. S45
Author(s):  
S. Syberg ◽  
A. Brandao-Burch ◽  
J.J. Patel ◽  
M.O. Hajjawi ◽  
T.R. Arnett ◽  
...  

2012 ◽  
Vol 27 (11) ◽  
pp. 2373-2386 ◽  
Author(s):  
Susanne Syberg ◽  
Andrea Brandao-Burch ◽  
Jessal J Patel ◽  
Mark Hajjawi ◽  
Timothy R Arnett ◽  
...  

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