Intradiscal thermal therapy using interstitial ultrasound: an in vivo investigation in ovine cervical spine.

Study Design: In vivo investigation of intradiscal ultrasound thermal therapy in ovine cervical spine model.

Objective: To evaluate the potential of interstitial ultrasound for selective heating of intradiscal tissue in vivo.

Summary Of Background Data: Application of heat in the spine using resistive wire and radiofrequency current heating devices is currently being used clinically for minimally invasive treatment of discogenic low back pain.

Effects of growth differentiation factor-5 on the intervertebral disc--in vitro bovine study and in vivo rabbit disc degeneration model study.

Study Design: In vitro studies on the effects of recombinant human growth and differentiation factor-5 (rhGDF-5) on matrix metabolism of bovine intervertebral disc cells and an in vivo study on the effect of rhGDF-5 in the rabbit anular puncture model.

Objective: To determine the reparative capacity of rhGDF-5 on the intervertebral disc.

Summary Of Background Data: The in vitro and in vivo effects of rhGDF-5, a crucial protein in the developing musculoskeletal system, on repair of the degenerated intervertebral disc remain unidentified.

Platelet-rich plasma (PRP) stimulates the extracellular matrix metabolism of porcine nucleus pulposus and anulus fibrosus cells cultured in alginate beads.

Study Design: In vitro assessment of the effects of platelet-rich plasma on the extracellular matrix metabolism of porcine intervertebral disc cells.

Objectives: To determine whether platelet-rich plasma is effective in stimulating cell proliferation and extracellular matrix metabolism by porcine disc cells cultured in alginate beads.

Summary Of Background Data: Platelet-rich plasma is used to accelerate wound healing and tissue regeneration.

Bone grafts prepared with selective cell retention technology heal canine segmental defects as effectively as autograft.

Using a canine critical-size segmental defect model, a two-phased study was undertaken to evaluate the healing efficacy of demineralized bone and cancellous chips (DBM-CC) enriched with osteoprogenitor cells using a Selective Cell Retention (SCR) technology. The goals of this study were: 1) to determine the bone-healing efficacy of SCR-enriched grafts versus autograft, and 2) to assess the value of clotting SCR-enriched grafts with platelet-rich plasma (PRP). Thirty dogs were included in Phase I: 18 dogs were treated with an SCR-enriched DBM-CC graft clotted with autologous bone marrow, and were compared to 12 autograft controls.

Intradiscal thermal therapy does not stimulate biologic remodeling in an in vivo sheep model.

Study Design: Thermal energy was delivered in vivo to ovine cervical discs and the postheating response was monitored over time.

Objectives: To determine the effects of two distinctly different thermal exposures on biologic remodeling: a "high-dose" regimen intended to produce both cellular necrosis and collagen denaturation and a "low-dose" regimen intended only to kill cells.

Summary Of Background Data: Thermal therapy is a minimally invasive technique that may ameliorate discogenic back pain.

Molecular regulation of osteoblasts for tissue engineered bone repair.

The use of biodegradable polymers in medicine and biomedical research is increasing. A key growth area has been the use of these materials in tissue engineering, especially for guided regeneration of bone and cartilage. Our interest has been in determining the mechanisms by which cellular attachment and growth occurs on these materials.

Cryopreservation of tissue engineered constructs for bone.

The large-scale clinical use of tissue engineered constructs will require provisions for its mass availability and accessibility. Therefore, it is imperative to understand the effects of low temperature (-196 degrees C) on the tissue engineered biological system. Initial studies used samples of the osteoblast-like cell line (SaOS-2) adhered to a two-dimensional poly(lactide-co-glycolide) thin film (2D-PLAGA) or a three-dimensional poly(lactide-co-glycolide) sintered microsphere matrix (3D-PLAGA) designed for bone tissue engineering.

The sintered microsphere matrix for bone tissue engineering: in vitro osteoconductivity studies.

A tissue engineering approach has been used to design three-dimensional synthetic matrices for bone repair. The osteoconductivity and degradation profile of a novel polymeric bone-graft substitute was evaluated in an in vitro setting. Using the copolymer poly(lactide-co-glycolide) [PLAGA], a sintering technique based on microsphere technology was used to fabricate three-dimensional porous scaffolds for bone regeneration.

Integrin expression by human osteoblasts cultured on degradable polymeric materials applicable for tissue engineered bone.

The use of biodegradable polymers in the field of orthopaedic surgery has gained increased popularity, as surgical pins and screws, and as potential biological scaffolds for repairing cartilage and bone defects. One such group of polymers that has gained considerable attention are the polyesters, poly(lactide-co-glycolide) (PLAGA) and polylactic acid (PLA), because of their minimal tissue inflammatory response, favorable biocompatibility and degradation characteristics. The objective of this study was to evaluate human osteoblastic cell adherence and growth on PLAGA and PLA scaffolds by examining integrin receptor (alpha2, alpha3, alpha4, alpha5, alpha6 and beta1) expression.

Tissue engineered microsphere-based matrices for bone repair: design and evaluation.

The need for synthetic alternatives to conventional bone grafts is due to the limitations of current grafting materials. Our approach has been to design polymer-based graft substitutes using microsphere technology. The gel microsphere matrix and the sintered microsphere matrix were designed using the random packing of poly(lactide-co-glycolide) microspheres to create a three-dimensional porous structure.