Biomedical subjects

Joon Yung Lee

Publications and source records attributed to Joon Yung Lee.

2 recordsLinked to original sources

PubMed2005

Nucleus pulposus replacement: basic science and indications for clinical use.

STUDY DESIGN: A critical review of available and emerging nucleus pulposus replacement implants. OBJECTIVES: To review the biomechanics, design, and clinical data of currently available and developing nucleus pulposus replacement technologies. SUMMARY OF BACKGROUND DATA: The interest in minimally invasive treatment of degenerative disc disease has grown as the technology for intervertebral motion-sparing devices continues to improve. Replacement of nucleus pulposus without anular obliteration represents a tempting alternative to spinal fusion procedures. The aim in nucleus pulposus replacement is to slow adjacent level degeneration, restore normal loads to the diseased level, and restore segmental spinal biomechanics. METHODS: A literature review of currently available biomaterials, biomechanics, and available preclinical and clinical data on nucleus pulposus replacement implants. RESULTS: New synthetic biomaterials have recently been developed to closely mimic native biomechanics during compressive loading cycles of the intervertebral disc. This, in conjunction with improved understanding of global spine biomechanics, has allowed the development of novel nucleus replacement implants. These implants are currently at different stages of preclinical and clinical investigations. CONCLUSIONS: Although some of the newly designed prosthesis have shown some promising results in preclinical studies, rigorous short- and long-term clinical evaluations will be critical in evaluating their true efficacy.

Biocompatible Materials↗

PubMed2002

Enhancement of bone healing based on ex vivo gene therapy using human muscle-derived cells expressing bone morphogenetic protein 2.

Molecular biological advances have allowed the use of gene therapy in a clinical setting. In addition, numerous reports have indicated the existence of inducible osteoprogenitor cells in skeletal muscle. Because of this, we hypothesized that skeletal muscle cells might be ideal vehicles for delivery of bone-inductive factors. Using ex vivo gene transfer methods, we genetically engineered freshly isolated human skeletal muscle cells with adenovirus and retrovirus to express human bone morphogenetic protein 2 (BMP-2). These cells were then implanted into nonhealing bone defects (skull defects) in severe combined immune deficiency (SCID) mice. The closure of the defect was monitored grossly and histologically. Mice that received BMP-2-producing human muscle-derived cells experienced a full closure of the defect by 4 to 8 weeks posttransplantation. Remodeling of the newly formed bone was evident histologically during the 4- to 8-week period. When analyzed by fluorescence in situ hybridization, a small fraction of the transplanted human muscle-derived cells was found within the newly formed bone, where osteocytes normally reside. These results indicate that genetically engineered human muscle-derived cells enhance bone healing primarily by delivering BMP-2, while a small fraction of the cells seems to differentiate into osteogenic cells.

Adenoviridae↗