A comparative chemical and histochemical study of the chondrodystrophoid and nonchondrodystrophoid canine intervertebral disc.
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The chemical composition of the intervertebral disc of 9-month-old chondrodystrophoid and nonchondrodystrophoid dogs was studied for collagen, noncollagenous protein and glycosaminoglycan. Content of these substances differed significantly between breeds. The differences were most marked in the nucleus pulposus; the noncollagenous protein content of the nonchondrodystrophoid breed was higher than in that of the chondrodystrophoid dogs. The total nitrogen value of the nonchondrodystrophoid nuclei pulposi was less than that of the corresponding chondrodystrophoid discs mainly because of the high collagen content of the latter discs. Histochemically, it was found that the nuclei pulposi of the nonchondrodystrophoid breed contains larger amounts of glycosaminoglycan than in the discs of the chondrodystrophoid breeds. (+info)
Gender differences in knee cartilage volume as measured by magnetic resonance imaging.
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OBJECTIVE: The aim of this study was to analyze sex differences in knee cartilage volume. METHODS: Articulate cartilage volumes were determined by processing images acquired in the sagittal plane using T1-weighted fat saturation magnetic resonance on an independent work station. The knees of 28 subjects (17 male, 11 female) who underwent MRI for clinical indications (pain <3 months) but who had a normal X-ray and structurally normal MRI were examined. RESULTS: Males had significantly larger cartilage volumes than females, with difference in cartilage volume remaining statistically significant after adjusting for age, height, weight and bone volume. The differences for males relative to females were: femoral cartilage volume [4.1 ml 95% CI (2.0, 6.1)]; and patella cartilage volume [1.4 ml (0.2, 2.7)]. Although not statistically significant, the tibial cartilage volume also showed these sex differences. Exploratory analysis indicated an increasing gender difference with increasing age for patellar cartilage volume. CONCLUSION: Men have significantly larger knee cartilage volume than women, independent of body and bone size. The mechanisms for this will need to be determined. (+info)
Immunohistochemical observations on the initial disorders of the epiphyseal growth plate in rats induced by high dose of vitamin A.
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The initial disorders of the epiphyseal growth plate cartilage were immunohistochemically examined in the proximal tibia of rats administered a high dose of vitamin A. Male Wistar rats were given 100,000 IU/100 g body weight/day of vitamin A for administration periods of 1 to 5 days (Day 1 to 5) from 4 weeks after birth or were given deionized water and used as control. They were sacrificed after 5-bromo-2'-deoxyuridine (BrdU) injection on Day 1 to Day 5 to remove the tibiae. The tibiae were processed for immunohistochemical examinations using antibodies against type I, II, X collagens and BrdU. BrdU-incorporated chondrocytes and type X collagen-negative area were reduced since Day 2 and type X collagen-positive area was reduced since Day 4. The cartilage matrix partially lost type II collagen and deposited type I collagen in the epiphyseal growth plate near the periosteum on Day 5. These findings suggest that a high dose of vitamin A initially disturbed the differentiation from resting to proliferating chondrocytes, subsequently inhibited the differentiation from proliferating to hypertrophic chondrocytes, caused the chondrocytes to deviate from the process of normal differentiation, and finally resulted in the deformation of the epiphyseal growth plate. (+info)
Articular cartilage repair: are the intrinsic biological constraints undermining this process insuperable?
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This article reviews the experimental and clinical strategies currently in use or under development for the treatment of articular cartilage lesions. The vast majority of protocols under investigation pertain to the treatment of full-thickness defects (i.e., those which penetrate the subchondral bone and trabecular-bone spaces) rather than partial-thickness ones (i.e., those which are confined to the substance of articular cartilage tissue itself). This bias probably reflects the circumstance that partial-thickness defects do not heal spontaneously whereas full-thickness ones below a critical size do, albeit transiently. And it is, of course, a seemingly easier task to manipulate a process which is readily set in train than it is to overcome an induction-problem which Nature herself has not solved. Indeed, the reasons for this inert state of partial-thickness defects have only recently been elucidated, and these are briefly discussed. However, the main body of this review deals with the various transplantation concepts implemented for the repair of full-thickness defects. These fall into two broad categories: tissue-based (entailing the grafting of perichondrial, periosteal, cartilage or bone-cartilage material) and cell-based (utilizing chondroblasts, chondrocytes, periochondrial cells or mesenchymal stem cells). Cell-based systems are further subdivided according to whether cells are transplanted within a matrix (biodegradable, non-biodegradable or synthetic) or free in suspension. Thus far, the application of cell suspensions has always been combined with the grafting of a periosteal flap. The strengths and weaknesses of each concept are discussed. (+info)
Biomechanics of integrative cartilage repair.
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Cartilage repair is required in a number of orthopaedic conditions and rheumatic diseases. From a macroscopic viewpoint, the complete repair of an articular cartilage defect requires integration of opposing cartilage surfaces or the integration of repair tissue with the surrounding host cartilage. However, integrative cartilage repair does not occur readily or predictably in vivo. Consideration of the 'integrative cartilage repair process', at least in the relatively early stages, as the formation of a adhesive suggests several biomechanical approaches for characterizing the properties of the repair tissue. Both strength of materials and fracture mechanics approaches for characterizing adhesives have recently been applied to the study of integrative cartilage repair. Experimental configurations, such as the single-lap adhesive test, have been adapted to determine the strength of the biological repair that occurs between sections of bovine cartilage during explant culture, as well as the strength of adhesive materials that are applied to opposing cartilage surfaces. A variety of fracture mechanics test procedures, such as the (modified) single edge notch, 'T' peel, dynamic shear, and trouser tear tests, have been used to assess Mode I, II, and III fracture toughness values of normal articular cartilage and, in some cases, cartilaginous tissue undergoing integrative repair. The relationships between adhesive biomechanical properties and underlying cellular and molecular processes during integrative cartilage repair remain to be elucidated. The determination of such relationships may allow the design of tissue engineering procedures to stimulate integrative cartilage repair. (+info)
Concerning the ultrastructural origin of large-scale swelling in articular cartilage.
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The swelling behaviour of the general matrix of both normal and abnormally softened articular cartilage was investigated in the context of its relationship to the underlying subchondral bone, the articular surface, and with respect to the primary structural directions represented in its strongly anisotropic collagenous architecture. Swelling behaviours were compared by subjecting tissue specimens under different modes of constraint to a high swelling bathing solution of distilled water and comparing structural changes imaged at the macroscopic, microscopic and ultrastructural levels of resolution. Near zero swelling was observed in the isolated normal general matrix with minimal structural change. By contrast the similarly isolated softened general matrix exhibited large-scale swelling in both the transverse and radial directions. This difference in dimensional stability was attributed to fundamentally different levels of fibril interconnectivity between the 2 matrices. A model of structural transformation is proposed to accommodate fibrillar rearrangements associated with the large-scale swelling in the radial and transverse directions in the softened general matrix. (+info)
Para-articular chondroma and osteochondroma of the infrapatellar fat pad: a report of three cases.
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We report three cases of para-articular chondroma and osteochondroma in the region of infrapatellar fat pad. All three lesions were resected and examined histologically. Two of them were primarily cartilaginous with a lobular pattern internally, and one uniformly osseous with peripheral cartilage. We conclude that these lesions are not the same. The former should be designated para-articular chondroma after Jaffe and the latter, osteochondroma. (+info)
Premature termination codon in the aggrecan gene of nanomelia and its influence on mRNA transport and stability.
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AIM: To analyze the influence of the premature termination codon on mRNA transport and stability METHODS: Chondrocyte mRNA was isolated from homozygous and heterozygous nanomelic 17-days old embryos and examined by RT-PCR analysis. To analyze aggrecan mRNA stability, mRNA synthesis was inhibited with DRB [5,6 dichloro-1-(-D-ribofuranosyl benzimidazole)], a specific inhibitor of RNA polymerase II. Visualization of the aggrecan alleles was performed by in situ hybridization. RESULTS: The level of mutant aggrecan mRNA within the nucleus was equal to that of the control, but no mutant mRNA was observed in the cytoplasm. RT-PCR revealed that the mutant transcript was only detectable in the nucleus, compared with house-keeping glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene or collagen type II. A restriction site induced by premature termination codon TAA allowed the distinction of normal and mutant transcripts in chondrocytes derived from embryos heterozygous for the nanomelic mutation. After the treatment with DRB, identical decay rates were demonstrated for both transcripts within the heterozygous nucleus. In situ hybridization showed no abnormal mRNA accumulation. CONCLUSION: This is the first evidence suggesting that the transcript of the mRNA with the premature termination codon within an exon does exit the nucleus. (+info)