David C. Van Sickle

Cambium cell stimulation from surgical release of the periosteum

An autograft of periosteal tissue containing cambium cells has potential to become chondrogenic or osteogenic depending on the regeneration repair strategies. The potential number of harvestable cambium cells diminishes with age. Other factors may be associated with a reduction in the number or variable yields of cambium cells including harvest technique, harvest site location, and the time interval from harvest to implantation. Attempts to increase the number of cambium cells have included improvements in harvesting and handling technique, and expansion of the cells in tissue culture. An „in situ”︁ stimulation and proliferation technique would offer the potential for increasing the number of cambium cells in a cost‐effective manner for transplantation without the need for expansion in tissue culture.

Placental Transfer and Teratology of Pentachlorophenol in Rats

Pentachloro[U-14C]phenol was administered orally to Charles River CD strain pregnant rats on day 15 of gestation. Concentrations found in the placentas and fetuses up to 32 hr remained very small indicating that the amount that passes through the placental barrier is negligible. Unlabeled compound was administered on days 8, 9, 10, 11, 12, and 13 of gestation. The incidence of resorptions in the treated animals was not significantly greater than that in the controls. Although malformations were observed, the number was minimal and could have been due to the toxic effects of the compound on the maternal rat.

In vitro and in vivo evaluation of orthopedic interface repair using a tissue scaffold with a continuous hard tissue-soft tissue transition

Tendon tears produce pain and decrease joint stability; each year, over 1.1 million rotator cuff tendon surgical procedures are performed worldwide. However, surgical success is highly variable, and the inability of the procedure to drive the regeneration of the normal tendon-bone interface has been identified as a key factor in surgical failure. This study focuses on the development, in vitro evaluation, and in vivo assessment of a tissue scaffold derived from bovine cancellous bone with the potential to direct regeneration of a bone-soft tissue interface. The scaffold is a highly porous scaffold with a continuous hard tissue-soft tissue transition that facilitates load transfer across the interface and contains all of the extracellular matrix components of the orthopedic interface. This study demonstrated the in vitro characterization of the mechanical properties and successful in vivo assessment using an ovine model.

A Novel Suture Anchor of High-Density Collagen Compared With a Metallic Anchor Results of a 12-Week Study in Sheep

We report the early mechanical properties and histologic findings of a high-density, type I collagen bone anchor. This new anchor was compared with a traditional metallic anchor in a sheep patellar tendon model. No difference in strength of the repair was noted between the two devices at any time point. The insertions on the repaired side approached the strength of the nonoperated side by 12 weeks. Histologic analysis showed that the collagen anchor integrated with the surrounding bone by 6 weeks, and there was little degradation at 12 weeks. The high-density collagen anchor supported tendon healing to bone comparable with that seen with a traditional metallic device, but it has the potential advantage of the anchor being incorporated into bone.

Patellar Tendon-to-Bone Healing Using High-Density Collagen Bone Anchor at 4 Years in a Sheep Model

Background This study reports the long-term histologic and mechanical properties of the healing patellar tendon–bone interface reconstructed using a high-density type I collagen bone anchor (HDC) compared to a metal anchor in sheep. Hypothesis To determine the long-term histology and mechanical properties of extra-articular tendon-bone healing and in vivo response to a HDC anchor. Study Design Controlled laboratory study. Methods The structural properties, tendon-bone histology, and device histology in the bone were examined out to 208 weeks in a sheep model. Results The patellar tendon–proximal tibia bone interface continued to remodel with time but, by 4 years, had yet to develop the well-defined zones of tendon, fibrocartilage, calcified cartilage, and bone of the native patellar tendon to bone insertion. The insertion repair strength did not vary between the repaired tendons and the nonoperated controls at any time. Conclusion The healing tendon-bone interface undergoes a gradual remodeling process, which had yet to reconstitute back to the control interface by 208 weeks. The HDC device remained essentially intact at 208 weeks showing little signs of degradation. Clinical Relevance Tendon-bone healing is mechanically equivalent to the contralateral side by 26 weeks whereas histologic structure requires much longer to remodel back to the native insertion.

Biodistribution of bis[β-(N,N,N-trimethylamino)ethyl]selenide-75Se diiodide, a potential articular cartilage imaging agent

In an effort to develop a specific radiodiagnostic agent for articular cartilage imaging, we have investigated the biodistribution of bis[beta-(N,N,N-trimethylamino)ethyl]-selenide-75Se diiodide (75Se BISTAES) in rabbits. At an intravenous dose of 5 mg/kg, the greatest localization of the compound occurred in articular cartilage 15 min after injection. The compound was excreted rapidly in the urine. The results suggest that 75Se BISTAES has potential clinical use as an articular cartilage imaging agent.

Nonlinear Optical Microscopy and Spectroscopy of Articular Cartilage

Nonlinear optical microscopy is used to image living articular cartilage in situ without exogenous stains or dyes. Endogenous nonlinear optical signals may be used for image segmentation and to evaluate articular cartilage matrix health.