Mark A. Randolph

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BACKGROUND The avascular portion of the meniscus cartilage in the knee does not have the ability to repair spontaneously. HYPOTHESIS Cell-based therapy is able to repair a lesion in the swine meniscus. STUDY DESIGN Controlled laboratory study. METHODS Sixteen Yorkshire pigs were divided into four groups. A longitudinal tear was produced in the(More)
Hyaluronic acid is a natural polysaccharide found abundantly throughout the body with many desirable properties for application as a biomaterial, including scaffolding for tissue engineering. In this work, hyaluronic acid with molecular weights ranging from 50 to 1100 kDa was modified with methacrylic anhydride and photopolymerized into networks with a wide(More)
In this study, devitalized meniscal tissue pre-seeded with viable cultured chondrocytes was used to repair a bucket-handle incision in meniscal tissue transplanted to nude mice. Lamb knee menisci were devitalized by cyclic freezing and thawing. Chips measuring four by two by one-half millimeters were cut from this devitalized tissue to serve as scaffolds.(More)
The reconstruction, repair, and regeneration of the external auricular framework continue to be one of the greatest challenges in the field of tissue engineering. To replace like with like, we should emulate the native structure and composition of auricular cartilage by combining a suitable chondrogenic cell source with an appropriate scaffold under optimal(More)
We developed an experimental model to compare the efficacy of free vascularized bone grafts, conventional segmental autografts, matchstick autografts, and fresh segmental allografts in terms of their ability to reconstruct a 7-cm segmental diaphyseal defect created in the canine femur. Forty-five adult mongrel dogs were studied and followed for 6 to 12(More)
The objective of this study was to determine how changes in the network structure and properties of hyaluronic acid (HA) hydrogels, due to variations in the macromer molecular weight (50-1,100 kDa) and macromer concentration (2-20 wt %), affect neocartilage formation by encapsulated auricular chondrocytes. To investigate tissue formation, swine auricular(More)
At present, the transplantation of vascularized limb-tissue allografts can be achieved only with generalized host immunosuppression, which results in significant systemic toxicity, thereby precluding their clinical use. A better understanding of the immunogenic mechanisms of these allografts may permit less toxic and thus clinically applicable means of host(More)
Engineered cartilage composed of a patient's own cells can become a feasible option for auricular reconstruction. However, distortion and shrinkage of ear-shaped constructs during scaffold degradation and neocartilage maturation in vivo have hindered the field. Scaffolds made of synthetic polymers often generate degradation products that cause an(More)
Photopolymerizations are widely used in medicine to create polymer networks for use in applications such as bone restorations and coatings for artificial implants. These photopolymerizations occur by directly exposing materials to light in "open" environments such as the oral cavity or during invasive procedures such as surgery. We hypothesized that light,(More)
The capacity of isolated chondrocytes to join separate masses of cartilage matrix was investigated with composites implanted in subcutaneous pouches in nude mice. Slices of articular cartilage were harvested from lambs and were devitalized by cyclic freezing and thawing. The slices were then either co-cultured with viable allogeneic lamb chondrocytes(More)