We studied human specimens and compared data on cartilage thickness measurements with magnetic resonance imaging by using an image analysing system with corresponding histological sections in the middle of each sector. The findings are based on 768 measurements in 26 knee joints. Overall, there was very good magnetic resonance/anatomic correlation (r=0.88). The poorest correlation was in the sectors of the femur (r=0.69). The correlation seemed not to be dependent on the grade of osteoarthritic cartilage lesions. Despite good correlation rates, the mean magnetic resonance/anatomic difference (absolute values) was 0.41 mm (standard deviation (SD) 0.34 mm) or 18.08% (SD 18.9%). Imaging techniques need to be improved if the assessment of cartilage thickness by this means is to be of clinical relevance .Résumé Nous avons examiné des speciments humains et comparé les dates des mesures de l'épaisseur du cartilage avec le MRI utilisant un système "image analysing" avec les séctions histologiques correspondantes dans le centre de chaque secteur. Les résultats sont fondés sur 768 mesures de 26 articulations du genou. Tous ensemble, la correlation magnetique resonance/anatomique était tres bien (r=0.88). La correlation plus petite dans notre exanination était dans les secteurs du femur (r=0.69). La correlation était apparement independante du degré des lésions osteoarthritique du cartilage. En dépit des taux positifs de correlation, la difference moyenne magnetique resonance/anatomique (valeurs absolues) était 0.41 mm (écart-type (EC): 0.34 mm) ou 18.08% (EC 18.9%). Les techniques d`images ont besoin d`améloriation si les mesures de l'épaisseur du cartilage avec le MRI semble important pour les questions médicales. Il faut considérer les differences selon la localisation en évaluant l'épaisseur du cartilage avec le MRI.
IntroductionIn the evaluation of cartilage lesions, arthroscopy is still the "gold standard". However, arthroscopy is invasive and is less informative about cartilage thickness. Ultrasonography has the potential to provide information on the cartilage layer but access to the knee joint is restricted. Techniques to assess cartilage thickness by arthrography and X-ray measurements have been described [4,8,12]; however, they mainly provide information on the joint space. These methods are of only minor value. By contrast, magnetic resonance imaging (MRI) provides a non-invasive image of the cartilage layer. It has been recommended that in cartilage imaging with MRI there should be high resolution, thin planar slices without gaps and with good discrimination of the cartilage relative to the surrounding tissue [9]. A sequence termed "fast imaging with steady state precession" (FISP) has proved to be very effective in the evaluation of knee disorders [7,24] and meets these criteria. The following study of human knee joints compares cartilage thickness measurements by MRI with corresponding histological sections.
Materials and methodsWe removed 30 fully encapsulated human knee joints at autopsy. Gross de...
Perifibrillar adapter proteins, interconnecting collagen fibrils, and linking the collagen network with the aggrecan matrix seem to play a crucial role in the pathogenesis of osteoarthritis (OA). Therefore, we examined immunohistochemically the extracellular distribution of collagen II and the main perifibrillar adapter proteins-collagen IX, decorin, cartilage oligomeric matrix protein (COMP), and matrilin-3-in human samples of healthy (n=4) and OA (n=42) knee joint cartilage. Histopathology assessment was performed using an OA score. Staining patterns were evaluated in relation to the disease stage. The perifibrillar adapter proteins were uniformly distributed in the upper zones of healthy cartilage. In moderate OA (n=8; score 14.3 ± 4.7), all proteins analyzed were locally absent in the fibrillated area or the superficial and upper mid zone. In advanced OA (n=20; score 18.9 ± 5.3), they were uniformly distributed in these zones and accumulated pericellularly. Perifibrillar adapter proteins are important for the stabilization of the collagen network in the upper zones of healthy cartilage. Their degradation might be a critical event in early OA. In advanced OA, there are indications for an increased synthesis in an attempt to regenerate the lost tissue and to protect the remaining cartilage from further destruction.
Objective. We have previously shown that human articular chondrocytes synthesize large amounts of interleukin-6 (IL-6) upon stimulation with proinflam-matory cytokines and that they express the IL-6 receptor. The present study was undertaken to analyze whether different IL-6-type cytokines can induce synthesis of the acute-phase protein 1-antitrypsin in human articular chondrocytes. Methods. Chondrocytes from human articular cartilage, cultured in agarose, were stimulated with IL-6-type cytokines. Total RNA was isolated and analyzed by Northern blotting. Levels of 1-antitrypsin protein were determined by enzyme immunoassay. Results. Stimulation of chondrocytes with on-costatin M (OSM) and IL-6 led to a 5-10-fold increase in 1-antitrypsin synthesis. This increase was dose and time dependent. Furthermore, OSM and IL-6 induced IL-6 synthesis in chondrocytes, resulting in an autocrine amplification loop. Conclusion. Our data strongly suggest the existence of a local acute-phase response in the joint.
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