Chondrocyte cultures from human proximal interphalangeal finger joints.

Osteoarthritis (OA) of the hand is a common disease resulting in pain and impaired function. The pathogenesis of hand OA (HOA) is elusive and models to study it have not been described. Chondrocyte culture has been essential to understand cartilage degeneration, which is a hallmark of OA. We investigated the feasibility of human chondrocyte culture derived from proximal interphalangeal (PIP) finger joints. Hyaline cartilage of the PIP and knee joints was obtained from human cadavers. Chondrocytes harvested up to 236 h after death of the donors were viable and expressed chondrocyte-specific genes. Gene expression comparing chondrocytes from PIP and knee joints using Affymetrix GeneChip arrays resulted in a unique PIP-specific gene expression pattern. Genes involved in developmental processes including the WNT pathway were differentially expressed between the joints. These findings suggest that our knowledge on chondrocyte biology derived mainly from knee and hip joints may not apply to chondrocytes of the PIP joints and some of the distinctive features of HOA may be caused by the specific properties of PIP chondrocytes. Chondrocyte culture of PIP cartilage is a novel tool to study cartilage degeneration in HOA. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1569-1575, 2016.

A higher order diffusion model for three-dimensional photon migration and image reconstruction in optical tomography.

In this work, we derived three-dimensional simplified spherical harmonics approximated higher order diffusion equations. We also solved the higher order diffusion equations using a finite element method and compared the solutions from the first-order diffusion equation and Monte Carlo simulations. We found that the conducted model is able to improve the first-order diffusion solution in a transport-like homogeneous or heterogeneous medium. Reconstructed images based on the higher order diffusion model are also presented. We conclude that the developed higher order diffusion model is able to accurately describe light propagation in biological tissues and to offer improved image reconstruction.

Capsular tissues of the proximal interphalangeal joint: normal composition and effects of Dupuytren's disease and rheumatoid arthritis.

Three fibrocartilages associated with the proximal interphalangeal joint are described--at the attachment of the central slip to bone, within the slip where it passes over the joint, and the volar plate. Material was obtained at surgery following trauma, Dupuytren's disease and rheumatoid arthritis. The fibrocartilages were structurally distinct and immunolabelled differently with monoclonal antibodies to extracellular matrix components. All fibrocartilages from normal and Dupuytren's fingers contained chondroitin and keratan sulphate. Type II collagen was present in all attachment zones, although there was little in rheumatoid fingers. It was also present in the dorsal hood of some normal fingers, but not in pathological specimens or the volar plate. The results show that the fibrocartilages are dynamic tissues whose composition varies according to function and use, and changes in disease.