Chemical composition and swelling of normal and osteoarthrotic femoral head cartilage. I. Chemical composition.

Abstract

SUMMARY Radiochemical and biochemical methods were used to characterize post-mortem and osteoarthrotic femoral head cartilage. Fixed charge density measurements were correlated with glycosaminoglycan content as estimated by uronic acid and hexosamine analyses. In post-mortem cartilage water content decreased from a maximum at the surface to a minimum in the deep zones. In the osteoarthrotic specimens water content was greatest in the middle zones. Glycosaminoglycan content increased with depth and in the osteoarthrotic specimens was reduced throughout the depth of the cartilage. With increasing degeneration there was an increase in water content and decrease in glycosaminoglycan content. The difference in the water content profile in osteoarthrotic cartilage was explained in terms of damage to the collagen network. In osteoarthrosis the latter is no longer capable of restraining the swelling pressure produced by the glycosaminoglycans and swelling is greatest in the midzones, where glycosaminoglycan content is highest.Topographical variations in the total glycosaminoglycan content of human cartilage has been studied using the fixed charge density (FCD) method in post-mortem specimens of the hip (Maroudas et al., 1973) and knee (Ficat and Maroudas, 1975). FCD measurements have been correlated with biochemical analyses for cartilage of the human femoral condyle (Maroudas et al., 1969). Chondroitin sulphate showed small variations with depth but keratan sulphate content increased with depth from the surface. Chemical analyses have also been correlated with the distribution of histochemical staining (Stockwell and Scott, 1967). A similar distribution pattern has been described for bovine knee cartilage when the glycosaminoglycans were separated as their macromolecules (Lemperg et al., 1974).The aims of the present study were first to confirm that the FCD as measured by the tracer cation method (Maroudas and Thomas, 1970;Maroudas et al., 1973) agreed over a wide range of concentrations with the values calculated from chemical determinations of uronic acid and hexosamine, and second, to compare topographical variations in the

Effect of multislice acquisition on T1 and T2 measurements of articular cartilage at 3T

“…T 1 -calculated maps of patellar cartilage at the center slice as measured by single-slice and multislice acquisition overlaid on morphological images in a representative case are shown in Fig. 4 4], respectively, a significant difference (P Ͻ 0.05). The average MIS %variation of superficial and deep layers were 6.6 Ϯ 4.7% [2.8 -19.0] and 6.3 Ϯ 2.8% [2.6 -10.7], respectively, a nonsignificant difference.…”

“…Because early degeneration of cartilage is characterized by deterioration of the extracellular matrix components (3)(4)(5) such as glycosaminoglycan (GAG) and collagen, qualitative MRI techniques have the potential to identify cartilage degeneration in an early stage. Delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) is a qualitative MRI technique that can evaluate the concentration of GAG in cartilage (6,7).…”

Aged bovine chondrocytes display a diminished capacity to produce a collagen-rich, mechanically functional cartilage extracellular matrix

“…Hydroxyproline residues from hydrolyzed aliquots of the papain digest were oxidized with chloramine-T hydrate and quantified following the colorimetric reaction with Ehrlich's reagent. Collagen contents were evaluated assuming that 13.2% of collagen mass originated from hydroxyproline residues [16,37]. Aliquots from identically processed agarose disks, but without cells, were added to standard curves to account for any potential interference from agarose hydrogel.…”

A Bimodular Theory for Finite Deformations: Comparison of Orthotropic Second-order and Exponential Stress Constitutive Equations for Articular Cartilage

“…Cartilage is composed of chondrocytes embedded in an extracellular ma trix consisting primarily of proteoglycans, a crosslinked collagen network, and water. The proteoglycans are negatively charged molecules that mainly resist compressive loads (Basser et al 1998;Lai et al 1991) while the collagen net work primarily resists tensile and shear loads (Mow and Ratcliffe 1997;Venn and Maroudas 1977). Due to this molecular structure, articular cartilage typically exhibits a mechanical response with marked anisotropy and tension-compression asymmetry (Akizuki et al 1986;Laasanen et al 2003;Soltz and Ateshian 2000;Wang et al 2003;Woo et al 1976Woo et al , 1979, and likely experiences finite, multi-dimensional strains due to typical in vitro and in vivo loads.…”