Introducing Microchannels into Chondrocyte-Seeded Agarose Hydrogels Influences Matrix Accumulation in Response to Dynamic Compression and TGF-β3 Stimulation

2011 ◽  
pp. 26-30 ◽  
Author(s):  
T. Mesallati ◽  
C. T. Buckley ◽  
T. Nagel ◽  
D. J. Kelly
Keyword(s):  
Dynamic Compression ◽  
Matrix Accumulation

scholarly journals Dynamic compression of chondrocyte-seeded fibrin gels: effects on matrix accumulation and mechanical stiffness

2004 ◽  
Vol 12 (2) ◽  
pp. 117-130 ◽  
Author(s):  
Christopher J. Hunter ◽  
Janna K. Mouw ◽  
Marc E. Levenston
Keyword(s):  
Dynamic Compression ◽  
Mechanical Stiffness ◽  
Fibrin Gels ◽  
Matrix Accumulation

Mechanical Loading Modulates Gene Expression in Chondrocyte-Seeded Agarose Hydrogels

2001 ◽  
Author(s):  
Sansan S. Lo ◽  
Robert L. Mauck ◽  
Sara L. Seyhan ◽  
Glyn D. Palmer ◽  
Van C. Mow ◽  
...  
Keyword(s):  
Gene Expression ◽  
Mechanical Loading ◽  
Promoter Activity ◽  
Dynamic Compression ◽  
Cell Phenotype ◽  
Mrna Levels ◽  
Matrix Deposition ◽  
Matrix Gene ◽  
The Matrix ◽  
Matrix Accumulation

Abstract A successful tissue engineered articular cartilage construct needs to possess mechanical, biochemical, and histological features similar to that of native cartilage in order to serve its load-bearing function. Agarose is a suitable scaffold material for chondrocyte cultures (1,2), allowing long-term maintenance of cell phenotype and the elaboration of a functional cartilage-like matrix. This culture system facilitates further elucidation of the roles of matrix and cell-matrix interactions in the regulation of chondrocyte response to mechanical loads. We have previously shown (3) that mechanical loading at a physiologic frequency can increase the rate of matrix deposition, increasing mechanical properties of the tissue engineered constructs (∼21 fold increases in HA over day 0 with loading vs. ∼4 fold increases for free swelling controls). We have also shown that dynamic loading of transiently transfected chondrocytes in agarose hydrogels for 1 hour at 10% strain increased aggrecan promoter activity by ∼1.5 fold (4). In this study we sought to further characterize the short term response of chondrocytes to static load (by measuring aggrecan promoter activity) and the effects of dynamic compression on aggrecan gene expression over a longer (3 day) culture period (by monitoring mRNA levels). Monitoring matrix gene expression during early times of culture, when there is little matrix accumulation and the cells deform directly with the matrix (5), may provide insights into cellular responses to strain and allow for the optimization of cartilage bioreactor conditions.

Influence of Cartilaginous Matrix Accumulation on Viscoelastic Response of Chondrocyte/Agarose Constructs Under Dynamic Compressive and Shear Loading

2008 ◽  
Vol 130 (5) ◽  
Author(s):  
Shogo Miyata ◽  
Tetsuya Tateishi ◽  
Takashi Ushida
Keyword(s):  
Energy Dissipation ◽  
Biochemical Composition ◽  
Dynamic Compression ◽  
Three Dimensional ◽  
Shear Stiffness ◽  
Relative Energy ◽  
Shear Loading ◽  
Cartilage Defects ◽  
Sgag Content ◽  
Matrix Accumulation

A method has been developed to restore cartilage defects by culturing autologous chondrocytes to create a three dimensional tissue and then implanting the cultured tissue. In this kind of approach, it is important to characterize the dynamic mechanical behavior of the regenerated cartilaginous tissue, because these tissues need to bear various dynamic loadings in daily life. The objectives of this study were to evaluate in detail the dynamic viscoelastic responses of chondrocyte-seeded agarose gel cultures in compression and torsion (shear) and to determine the relationships between these mechanical responses and biochemical composition. The results showed that both the dynamic compressive and shear stiffness of the cultured constructs increased during culture. The relative energy dissipation in dynamic compression decreased, whereas that in dynamic shear increased during culture. Furthermore, correlation analyses showed that the sulfated glycosaminoglycan (sGAG) content of the cultured construct showed significant correlations with the dynamic modulus in both compression and shear situations. On the other hand, the loss tangent in dynamic compression, which represents the relative energy dissipation capability of the constructs, showed a low correlation with the sGAG content, whereas this capability in shear exhibited moderate correlation. In conclusion, we explored the dynamic viscoelasticity of the tissue-engineered cartilage in dynamic compression and shear, and determined correlations between viscoelasticity and biochemical composition.

Atypical Femoral Fracture in McCune-Albright Syndrome

2020 ◽  
Vol 7 (3) ◽  
pp. 147-152
Author(s):  
Salman Ghaffari ◽  
◽  
Mehran Razavipour ◽  
Parastoo Mohammad Amini ◽  
◽  
...  
Keyword(s):  
Femoral Fracture ◽  
Dynamic Compression ◽  
Plate Fixation ◽  
Medullary Canal ◽  
Mccune Albright Syndrome ◽  
Café Au Lait Spots ◽  
History Of ◽  
Albright Syndrome ◽  
Mccune Albright

McCune-Albright Syndrome (MAS) is characterized by endocrinopathies, café-au-lait spots, and fibrous dysplasia. Bisphosphonates are the most prescribed treatment for reducing the pain but their long-term use has been associated with atypical fractures of cortical bones like femur in patients. We present a 23-year-old girl diagnosed with MAS. She had an atypical mid-shaft left femoral fracture that happened during simple walking. She also had a history of long-term use of alendronate. Because of the narrow medullary canal, we used 14 holes hybrid locking plate for the lateral aspect of the thigh to fix the fracture and 5 holes dynamic compression plate (instead of the intramedullary nail) in the anterior surface to double fix it, reducing the probability of device failure. With double plate fixation and discontinuation of alendronate, the complete union was achieved five months after surgery

STRAIN CHARACTERISTICS OF SOIL AND METHODS OF THEIR DETERMINATION

2018 ◽  
pp. 39-43
Author(s):  
K.S. Sultanov ◽  
P.V. Loginov ◽  
Z.R. Salikhova
Keyword(s):  
Dynamic Loading ◽  
Dynamic Compression ◽  
Loess Soil ◽  
Seismic Loads ◽  
Static Compression ◽  
Plastic Model ◽  
Laboratory Conditions ◽  
Coefficient Of Viscosity ◽  
Wave Problems

The method to define strain characteristics of soil under dynamic loading is proposed based on the results of experiments on dynamic compression of soils on the device for dynamic loading in laboratory conditions; the method allows solving wave problems with the statement similar to the statement of experiments. Using the proposed method, the modulus of dynamic and static compression, the modulus of unloading, the coefficient of viscosity of loess soil in the range of seismic loads are determined in accordance with elastic-visco-plastic model of soil developed by G.M.Lyakhov.

Mechanical properties and microstructure of the Al0.3CoCrFeNiTi0.3 high entropy alloy under dynamic compression

2021 ◽  
Vol 812 ◽  
pp. 141147
Author(s):  
Xianzhe Zhong ◽  
Qingming Zhang ◽  
Jing Xie ◽  
Mingze Wu ◽  
Fuqing Jiang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Dynamic Compression ◽  
High Entropy Alloy ◽  
High Entropy

scholarly journals All-trans retinoic acid regulating angiopoietins-1 and alleviating extracellular matrix accumulation in interstitial fibrosis rats

Renal Failure ◽  
2021 ◽  
Vol 43 (1) ◽  
pp. 658-663
Author(s):  
Zhiqing Zhong ◽  
Hong-Yan Li ◽  
Hongzhen Zhong ◽  
Wenshan Lin ◽  
Shujun Lin ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Retinoic Acid ◽  
Interstitial Fibrosis ◽  
Trans Retinoic Acid ◽  
All Trans Retinoic Acid ◽  
Matrix Accumulation
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