scholarly journals A technique for 3D in vivo quantification of proton density and magnetization transfer coefficients of knee joint cartilage

2000 ◽  
Vol 8 (6) ◽  
pp. 426-433 ◽  
Author(s):  
J Hohe ◽  
S Faber ◽  
T Stammberger ◽  
M Reiser ◽  
K.-H Englmeier ◽  
...  
Keyword(s):  
Knee Joint ◽  
Magnetization Transfer ◽  
Proton Density ◽  
Joint Cartilage ◽  
Transfer Coefficients

scholarly journals Silk fibroin hydrogel scaffolds incorporated with chitosan nanoparticles repair articular cartilage defects by regulating TGF-β1 and BMP-2

2021 ◽  
Vol 23 (1) ◽  
Author(s):  
Yuan Li ◽  
Yanping Liu ◽  
Qiang Guo
Keyword(s):  
Articular Cartilage ◽  
Knee Joint ◽  
Silk Fibroin ◽  
Cartilage Defects ◽  
Joint Cartilage ◽  
Hydrogel Scaffolds ◽  
Articular Cartilage Defects ◽  
Tgf Β1

AbstractCartilage defects frequently occur around the knee joint yet cartilage has limited self-repair abilities. Hydrogel scaffolds have excellent potential for use in tissue engineering. Therefore, the aim of the present study was to assess the ability of silk fibroin (SF) hydrogel scaffolds incorporated with chitosan (CS) nanoparticles (NPs) to repair knee joint cartilage defects. In the present study, composite systems of CS NPs incorporated with transforming growth factor-β1 (TGF-β1; TGF-β1@CS) and SF incorporated with bone morphogenetic protein-2 (BMP-2; TGF-β1@CS/BMP-2@SF) were developed and characterized with respect to their size distribution, zeta potential, morphology, and release of TGF-β1 and BMP-2. Bone marrow stromal cells (BMSCs) were co-cultured with TGF-β1@CS/BMP-2@SF extracts to assess chondrogenesis in vitro using a cell counting kit-8 assay, which was followed by in vivo evaluations in a rabbit model of knee joint cartilage defects. The constructed TGF-β1@CS/BMP-2@SF composite system was successfully characterized and showed favorable biocompatibility. In the presence of TGF-β1@CS/BMP-2@SF extracts, BMSCs exhibited normal cell morphology and enhanced chondrogenic ability both in vitro and in vivo, as evidenced by the promotion of cell viability and the alleviation of cartilage defects. Thus, the TGF-β1@CS/BMP-2@SF hydrogel developed in the present study promoted chondrogenic ability of BMSCs both in vivo and in vitro by releasing TGF-β1 and BMP-2, thereby offering a novel therapeutic strategy for repairing articular cartilage defects in knee joints.

scholarly journals A Phantom System Designed to Assess the Effects of Membrane Lipids on Water Proton Relaxation

2018 ◽  
Author(s):  
Oshrat Shtangel ◽  
Aviv A. Mezer
Keyword(s):  
Membrane Lipids ◽  
Magnetization Transfer ◽  
Membrane Lipid ◽  
Water Proton ◽  
Proton Relaxation ◽  
Proton Density ◽  
Brain Lipids ◽  
Water Fraction ◽  
Lipid Environment

AbstractPurposeQuantitative magnetic resonance imaging (qMRI) provides a method for the non-invasive study of brain structure and associated changes, expressed in physical units. qMRI parameters have been shown to reflect brain tissue composition such as myelin. Nevertheless, it remains a major challenge to identify and quantify the contributions of specific molecular components to the MRI signal. Here, we describe a phantom system that can be used to evaluate the contribution of human brain lipids to qMRI parameters.MethodsA thin layer evaporation-hydration technique was used to formulate liposomes that mimic the physiological bi-layered membrane lipid environment. We then applied quantitative clinical MRI techniques with adjusted bias corrections in order to test the ability of the phantom system to estimate multiple qMRI parameters such as proton density (PD), T1, T2, T2* and magnetization transfer (MT).ResultsThe results indicated that phantoms composed of various lipids could provide a stable and reliable estimation of qMRI parameters. In addition, the calculated water fraction (WF) maps for the phantoms were found to accurately represent the true WF volumes.ConclusionWe have successfully created a biologically relevant liposome phantom system whose lipid composition can be fully controlled. This system can be used to measure the contributions of lipids to qMRI parameters under conditions that are relevant to in-vivo human scans.

scholarly journals Magnetic Resonance Imaging in Experimental Models of Brain Disorders

2003 ◽  
Vol 23 (12) ◽  
pp. 1383-1402 ◽  
Author(s):  
Rick M. Dijkhuizen ◽  
Klaas Nicolay
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Imaging Modality ◽  
Magnetization Transfer ◽  
Treatment Strategies ◽  
Experimental Models ◽  
Proton Density ◽  
Brain Disorders ◽  
Resonance Imaging

This review gives an overview of the application of magnetic resonance imaging (MRI) in experimental models of brain disorders. MRI is a noninvasive and versatile imaging modality that allows longitudinal and three-dimensional assessment of tissue morphology, metabolism, physiology, and function. MRI can be sensitized to proton density, T1, T2, susceptibility contrast, magnetization transfer, diffusion, perfusion, and flow. The combination of different MRI approaches (e.g., diffusion-weighted MRI, perfusion MRI, functional MRI, cell-specific MRI, and molecular MRI) allows in vivo multiparametric assessment of the pathophysiology, recovery mechanisms, and treatment strategies in experimental models of stroke, brain tumors, multiple sclerosis, neurodegenerative diseases, traumatic brain injury, epilepsy, and other brain disorders. This report reviews established MRI methods as well as promising developments in MRI research that have advanced and continue to improve our understanding of neurologic diseases and that are believed to contribute to the development of recovery improving strategies.

Emodin protects knee joint cartilage in rats through anti-matrix degradation pathway: An in vitro and in vivo study

Life Sciences ◽  
2021 ◽  
pp. 119001
Author(s):  
Hailong Hu ◽  
Xiaopeng Song ◽  
Yue Li ◽  
Tianwen Ma ◽  
Hui Bai ◽  
...  
Keyword(s):  
Knee Joint ◽  
Degradation Pathway ◽  
In Vivo Study ◽  
Matrix Degradation ◽  
Joint Cartilage

scholarly journals An Evidence-Based Systematic Review of Human Knee Post-Traumatic Osteoarthritis (PTOA): Timeline of Clinical Presentation and Disease Markers, Comparison of Knee Joint PTOA Models and Early Disease Implications

2021 ◽  
Vol 22 (4) ◽  
pp. 1996 ◽  
Author(s):  
Christine M. Khella ◽  
Rojiar Asgarian ◽  
Judith M. Horvath ◽  
Bernd Rolauffs ◽  
Melanie L. Hart
Keyword(s):  
Synovial Fluid ◽  
Knee Joint ◽  
Ex Vivo ◽  
Disease Process ◽  
Early Disease ◽  
Knee Trauma ◽  
Post Traumatic ◽  
Acute Knee

Understanding the causality of the post-traumatic osteoarthritis (PTOA) disease process of the knee joint is important for diagnosing early disease and developing new and effective preventions or treatments. The aim of this review was to provide detailed clinical data on inflammatory and other biomarkers obtained from patients after acute knee trauma in order to (i) present a timeline of events that occur in the acute, subacute, and chronic post-traumatic phases and in PTOA, and (ii) to identify key factors present in the synovial fluid, serum/plasma and urine, leading to PTOA of the knee in 23–50% of individuals who had acute knee trauma. In this context, we additionally discuss methods of simulating knee trauma and inflammation in in vivo, ex vivo articular cartilage explant and in vitro chondrocyte models, and answer whether these models are representative of the clinical inflammatory stages following knee trauma. Moreover, we compare the pro-inflammatory cytokine concentrations used in such models and demonstrate that, compared to concentrations in the synovial fluid after knee trauma, they are exceedingly high. We then used the Bradford Hill Framework to present evidence that TNF-α and IL-6 cytokines are causal factors, while IL-1β and IL-17 are credible factors in inducing knee PTOA disease progresssion. Lastly, we discuss beneficial infrastructure for future studies to dissect the role of local vs. systemic inflammation in PTOA progression with an emphasis on early disease.

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