Correlation between biochemical composition and magnetic resonance appearance of articular cartilage

AbstractObjective: The objective of this study was to find a correlation between magnetic resonance (MR) appearance and biochemical composition of the normal articular cartilage by comparing the laminar aspects with the distribution of the two principal matrix components: proteoglycans and collagen.Design: T2-weighted MR microimages of porcine cartilage-bone plugs, excised from both the habitually loaded and habitually unloaded regions of the proximal end of the humerus, were obtained using a spin-echo sequence. Proteoglycans (PGs) were monitored by histology and by measuring the uronate and the sulfur content of the tissue; a histological method and the chemical determination of hydroxyproline were used for the evaluation of the collagen content.Results: The ‘loaded’ cartilage exhibited the expected MR laminar appearance whereas the ‘unloaded’ tissue appeared to be more homogeneous. The PG content in the ‘loaded’ cartilage, was found to be 2.4 times higher than in the habitually unloaded tissue, exhibiting an increasing trend from the articular surface to the bone. In the ‘unloaded’ cartilage the uronate distribution was more uniform with a higher concentration in the intermediate zone. The mean collagen content of both cartilage regions was found to be about 39% of the tissue dry weight. Histology and hydroxyproline distribution pattern showed that collagen was particularly concentrated at the surface and in a central zone of the ‘loaded’ cartilage whereas in the ‘unloaded’ tissue collagen was evident only at the surface. In accordance with the collagen distribution, transverse relaxation (T2) times in ‘loaded’ cartilage showed a minimum value at the articular surface and another minimum in a central region. On the contrary, the average T2value of the ‘unloaded’ tissue was high at the surface and decreased rapidly in the deeper zones.Conclusion: These results demonstrate that the MR appearance of articular cartilage correlates with the collagen content, but not with that of PGs, of the different zones. Other matrix components might, however, influence the MR appearance by contributing to the macromolecular organization of the tissue

Art-thérapies et Mineurs Non Accompagnés : indications, dispositifs et efficacités

International audienc

Les Mineurs Non Accompagnés (MNA) et le soutien psychologique par les arts : quels dispositifs pour quelles efficacités ?

International audienc

Art-thérapies et Mineurs Non Accompagnés : indications, dispositifs et bénéfices.

International audienc

Mineurs non Accompagnés et dispositifs d’art-thérapie : quelles indications ? quelseffets ?

International audienc

CD69 expression on a-gliadin-specific T cells in coeliac disease

Coeliac disease (CD) is a T-cell mediated immunological disease of the small intestine which is triggered in susceptible individuals by ingestion of gluten. The pathogenic mechanism of coeliac disease, and the role that a-gliadin specific T cells play in mucosal lesions and their involvement in peripheral blood is not yet explained at all. Previous studies have reported proliferative response to a-gliadin measured with the classic assay of 3HTdR incorporation. We analysed the activation antigen CD69 on T cells from CD patients and normal individuals following stimulation with a-gliadin and different antigens (tetanus toxoid, peptides unrelated to gliadin and PHA). CD69 coexpression with T cell CD3+ and proliferation marker Ki67 was evaluated with time. CD69 coexpression with T cell CD3+, CD4+ and CD8+ was also evaluated. It was found that peripheral blood mononuclear cells (PBMC) of coeliac patients increased their percentage of CD69 positive T cells when stimulated with a-gliadin, in comparison with cells from controls. Significant T cell activation was found only in subjects not treated with the gluten free diet; a positive response was found also in two coeliac patients with selective IgA deficiency, anti-endomisium negative, without circulat- ing IgA anti a-gliadin or anti-tissue transglutaminase antibodies. The CD69 expression after stimulation was compared with the standard method of 3HTdR incorporation. Our data show that CD69 expression is useful to asses a specific T cell response to a-gliadin in coeliac disease. in a very short time. Moreover, the method allows to investigate T cell response at the lymphocyte subsets level, which represents a useful tool in the diagnosis of coeliac disease

Sensitivity of chondrocytes of growing cartilage to reactive oxygen species.

BIOCHIMICA BIOPHYSICA ACT