In JoVE (5)
- Use of Human Perivascular Stem Cells for Bone Regeneration
- A Contusive Model of Unilateral Cervical Spinal Cord Injury Using the Infinite Horizon Impactor
- Capillary Force Lithography for Cardiac Tissue Engineering
- Engineering Platform and Experimental Protocol for Design and Evaluation of a Neurally-controlled Powered Transfemoral Prosthesis
- Sediment Core Sectioning and Extraction of Pore Waters under Anoxic Conditions
Articles by Michael Lee in JoVE
Use of Human Perivascular Stem Cells for Bone Regeneration Aaron W. James*1, Janette N. Zara*2, Mirko Corselli2, Michael Chiang1, Wei Yuan2, Virginia Nguyen1, Asal Askarinam1, Raghav Goyal1, Ronald K. Siu3, Victoria Scott1, Min Lee3, Kang Ting1, Bruno Péault2,4, Chia Soo2 1Dental and Craniofacial Research Institute and Section of Orthodontics, School of Dentistry, UCLA, 2UCLA and Orthopaedic Hospital, Department of Orthopaedic Surgery and the Orthopaedic Hospital Research Center, UCLA, 3Department of Bioengineering, UCLA, 4Center for Cardiovascular Science, University of Edinburgh Human perivascular stem cells (PSCs) are a novel stem cell class for skeletal tissue regeneration similar to mesenchymal stem cells (MSCs). PSCs can be isolated by FACS (fluorescence activated cell sorting) from adipose tissue procured during standard liposuction procedures, then combined with an osteoinductive scaffold to achieve bone formation in vivo.
A Contusive Model of Unilateral Cervical Spinal Cord Injury Using the Infinite Horizon Impactor Jae H.T. Lee1, Femke Streijger1, Seth Tigchelaar1, Michael Maloon1, Jie Liu1, Wolfram Tetzlaff1, Brian K. Kwon1,2 1International Collaboration on Repair Discoveries (ICORD), University of British Columbia, 2Department of Orthopaedics, University of British Columbia A reliable and repeatable way to produce a cervical unilateral spinal cord injury using the Infinite Horizon impactor is described. The method takes advantage of a custom designed frame and clamp to stabilize the spine. The standardized procedure and biomechanical injury parameters result in sufficient and sustained injuries.
Capillary Force Lithography for Cardiac Tissue Engineering Jesse Macadangdang1, Hyun Jung Lee1, Daniel Carson1, Alex Jiao1, James Fugate2, Lil Pabon2, Michael Regnier1, Charles Murry2, Deok-Ho Kim1 1Department of Bioengineering, University of Washington, 2Department of Pathology, University of Washington In this protocol, we demonstrate the fabrication of biomimetic cardiac cell culture substrata made from two distinct polymeric materials using capillary force lithography. The described methods provide a scalable, cost-effective technique to engineer the structure and function of macroscopic cardiac tissues for in vitro and in vivo applications.
Engineering Platform and Experimental Protocol for Design and Evaluation of a Neurally-controlled Powered Transfemoral Prosthesis Fan Zhang1, Ming Liu1, Stephen Harper2,3, Michael Lee3, He Huang1 1Joint Department of Biomedical Engineering, North Carolina State University & University of North Carolina at Chapel Hill, 2Department of Physical Medicine and Rehabilitation, University of North Carolina School of Medicine, 3Atlantic Prosthetics & Orthotics, LLC Neural-machine interfaces (NMI) have been developed to identify the user's locomotion mode. These NMIs are potentially useful for neural control of powered artificial legs, but have not been fully demonstrated. This paper presented (1) our designed engineering platform for easy implementation and development of neural control for powered lower limb prostheses and (2) an experimental setup and protocol in a laboratory environment to evaluate neurally-controlled artificial legs on patients with lower limb amputations safely and efficiently.
Sediment Core Sectioning and Extraction of Pore Waters under Anoxic Conditions Alison R. Keimowitz1, Yan Zheng2, Ming-Kuo Lee3, Michael Natter3, Jeffrey Keevan3 1Department of Chemistry, Vassar College, 2Division of Geochemistry, Lamont-Doherty Earth Observatory, 3Department of Geosciences, Auburn University A protocol for sectioning sediment cores and extracting pore waters under anoxic conditions in order to permit analysis of redox sensitive species in both solids and fluids is presented.
Other articles by Michael Lee on PubMed
Boundary Conditions During Biaxial Testing of Planar Connective Tissues. Part 1: Dynamic Behavior Journal of Materials Science. Materials in Medicine. Oct, 2002 | Pubmed ID: 15348186 Current mechanical testing methods used to determine the biaxial properties of planar connective tissues may lead to artifactual observations of material behavior. The method of sample gripping affects the constraint on the extracellular fibers at the bounds of the sample. This applied constraint not only affects how the load is transferred to the sample, but also how the load is transmitted throughout the rest of the material - thereby influencing the resulting mechanical behavior of the tissue. In this study, we compared the dynamic biaxial mechanical response of pericardial tissue samples under two different gripping methods: (i) the common method of suturing sample edges and (ii) a new biaxial clamping method. Tissue samples were repeatedly testing using both gripping methods under the same conditions. The tissue samples appeared to be stiffer and less extensible when mechanically tested with clamped sample edges, as opposed to when tested with sutured sample edges. Thus, the influence of the sample boundaries affected the response of the material - precisely the situation to be avoided for reliable material testing. This casts doubt on whether any in vitro mechanical testing method can used to determine the "real" properties of the tissue since the boundary conditions of the tissue in situ are presently unknown.
A Mutation in Cartilage Oligomeric Matrix Protein (COMP) Causes Early-onset Osteoarthritis in a Large Kindred Study Annals of Human Genetics. Sep, 2011 | Pubmed ID: 21834907 We performed a genome-wide linkage analysis to identify susceptibility loci in a large six-generation extended family previously reported with early-onset osteoarthritis (OA) DNA sequencing was performed to investigate involvement of the COMP (Cartilage oligomeric matrix protein) gene in this family. The region covering D19S884, D19S226, and D19S414 on chromosome 19p following genome-wide scan from 70 individuals of this kindred showed significant linkage, with a maximum point LOD (logarithm of the odds ratio) score of 2.51 at D19S226. Direct sequencing of the COMP gene, the most plausible candidate gene in the region, identified a c.2152C>T substitution in exon 18 which resulted in a substitution of tryptophan for arginine at position 718 located in the C terminal globular domain of the gene product. A total of 26 individuals were identified with this mutation of which 21 affected individuals had the mutation, and the other five younger individuals (18.6 ± 11.3 years of age) carried the mutation without symptoms. The results indicate that COMP is the disease susceptibility gene and the c.2152C>T mutation in exon 18 could cause early-onset OA phenotypes in this kindred, which is compatible with a previous report that this mutation also causes a mild form of multiple epiphyseal dysplasia (MED).
Interactions of U937 Macrophage-like Cells with Decellularized Pericardial Matrix Materials: Influence of Crosslinking Treatment Acta Biomaterialia. Jul, 2013 | Pubmed ID: 23454057 While macrophages have been implicated in the failure of bioprosthetic heart valves, the macrophage response to crosslinked native pericardial collagen has not been previously investigated. Using decellularized bovine pericardium (DBP) as a model for native collagen, this study investigated the response of macrophage-like cells (U937s) to DBP, either: (i) untreated, or (ii) exogenously crosslinked with glutaraldehyde or 1-ethyl-3-(3-dimethyl-aminopropyl)-carbodiimide (EDC). We have previously validated the use of U937 cells as models for the response of human monocyte-derived macrophages to decellularized pericardial materials and, per our previous work, differentiated the U937 cells directly on the three material surfaces. After 72h in culture, the cells and medium were analyzed for DNA content, acid phosphatase activity, and cytokine and matrix metalloproteinase release. As well, cell/substrate samples were fixed for SEM. Fewer cells attached to or survived on the glutaraldehyde-treated substrate, and some showed an abnormal morphology compared to cells cultured on the other surfaces. Further, cells on glutaraldehyde-treated surfaces released more pro-inflammatory cytokines, more MMP-1 and less MMP-2 and MMP-9. The poor performance of the U937 macrophage-like cells on the glutaraldehyde-treated surfaces appears to be due to surface characteristics rather than to soluble aldehyde or other components leaching from the crosslinked material. These results provide evidence that crosslinking with glutaraldehyde is cytotoxic to macrophage-like cells, and that crosslinking with a zero-length crosslinker like EDC can be an acceptable alternative crosslinking treatment for biomaterials.