Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “CARTILAGE, ARTICULAR”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 919 records · Page 51Linked to original sources
PubMed1988

Cation movement in rat articular and non-articular cartilage and in isolated chondrocytes: calcium influx and efflux.

1. Calcium ion influx varies between different types of young adult rat cartilage. Sternal cartilage accumulates significantly less Ca2+ than other cartilage types. 2. Influxes of Ca2+ into young adult and ageing tibial cartilage display no significant differences. 3. Efflux of Ca2+ from sternal and tibial cartilage resolves into exponential phases indicative of three compartments. Tracheal cartilage displays two compartment behaviour only. 4. Efflux of Ca2+ from isolated chondrocytes has different characteristics to cartilage efflux with the third slow compartment reduced. 5. Modification of Ca2+ efflux by lanthanum and barium is suggestive of an exchange of strongly bound extracellular calcium during the slow phase of the efflux from young adult tibial cartilage. 6. The metabolic inhibitor 2,4-dinitrophenol is without effect on the efflux of Ca2+ from tibial articular cartilage. 7. The degree of calcium binding exhibited during efflux depends upon cartilage type. Non-articular sternal cartilage binds calcium more strongly than articular tibial, both binding more strongly than non-articular tracheal cartilage. 8. In articular cartilage calcium binding shows an age-related increase.

2,4-Dinitrophenol↗
PubMed2002

Diffraction-enhanced X-ray imaging of articular cartilage.

OBJECTIVE: To introduce a novel X-ray technology, diffraction-enhanced X-ray imaging (DEI), in its early stages of development, for the imaging of articular cartilage. DESIGN: Disarticulated and/or intact human knee and talocrural joints displaying both undegenerated and degenerated articular cartilage were imaged with DEI. A series of three silicon crystals were used to produce a highly collimated monochromatic X-ray beam to achieve scatter-rejection at the microradian level. The third crystal (analyser) was set at different angles resulting in images displaying different characteristics. Once the diffraction enhanced (DE) images were obtained, they were compared to gross and histological examination. RESULTS: Articular cartilage in both disarticulated and intact joints could be visualized through DEI. For each specimen, DE images were reflective of their gross and histological appearance. For each different angle of the analyser crystal, there was a slight difference in appearance in the specimen image, with certain characteristics changing in their contrast intensity as the analyser angle changed. CONCLUSIONS: DEI is capable of imaging articular cartilage in disarticulated, as well as in intact joints. Gross cartilage defects, even at early stages of development, can be visualized due to a combination of high spatial resolution and detection of X-ray refraction, extinction and absorption patterns. Furthermore, DE images displaying contrast heterogeneities indicative of cartilage degeneration correspond to the degeneration detected by gross and histological examination.

Adult↗
PubMed1996

Articular cartilage volume in the knee: semiautomated determination from three-dimensional reformations of MR images.

PURPOSE: To determine the accuracy of semiautomated quantification of articular cartilage volume from three-dimensional (3D) reformations of magnetic resonance (MR) images. MATERIALS AND METHODS: Sagittal, fat-suppressed, 3D, spoiled gradient-recalled-echo MR imaging of two bovine and two human cadaver knees was performed. Articular cartilage volume was calculated from 3D reformations of the MR images by using a semiautomated program written at the authors' institution. Calculated volumes were compared with directly measured volumes of the surgically removed articular cartilage. RESULTS: The percentage of error of the MR imaging-determined volumes was 6.53% +/- 4.75 (mean +/- standard deviation). A strong correlation between the two sets of observations was shown (r=.997). Linear regression showed the calculated volumes to be highly accurate (slope=1.002, P>.25). Repeated reformations yielded volumes that were reproducible (mean absolute error, 0.013 mL +/- 0.019) and not significantly different from the measured volume (P>.10). CONCLUSION: Semiautomated quantification of knee articular cartilage from MR images yields highly accurate cartilage volumes.

Animals↗
PubMed2000

Repair of articular cartilage defects one year after treatment with recombinant human bone morphogenetic protein-2 (rhBMP-2).

BACKGROUND: Damaged articular cartilage has a limited ability to repair. Operative removal of damaged cartilage and penetration into the subchondral bone to allow population of the defect with progenitor cells can result in filling of the defect with repair tissue. However, this repair tissue often degenerates over time because of its inability to withstand the mechanical forces to which it is subjected. We previously reported that recombinant human bone morphogenetic protein-2 (rhBMP-2) improves the repair of full-thickness defects of cartilage as long as six months postoperatively. We have now extended that study to examine the quality of the repair tissue at one year. METHODS: Full-thickness defects of cartilage were created in the trochlear groove of twenty-five adult New Zealand White rabbits. Eight defects were left empty, eight were filled with a collagen sponge, and nine were filled with a collagen sponge impregnated with five micrograms of rhBMP-2. The animals were killed at fifty-two weeks postoperatively, and the gross appearance of the healed defect was assessed. The repair tissue was examined histologically and was evaluated, according to a grading scale, by four individuals who were blinded with respect to the treatment. The tissue sections were immunostained with antibodies against type-I collagen, type-II collagen, aggrecan, and link protein. The residence time of the rhBMP-2 in the cartilage defect was evaluated in vivo with use of scintigraphic imaging of radiolabeled protein. RESULTS: One year after a single implantation of a collagen sponge containing five micrograms of rhBMP-2, the defects had a significantly better histological appearance than the untreated defects (those left empty or filled with a collagen sponge). The histological features that showed improvement were integration at the margin, cellular morphology, architecture within the defect, and reformation of the tidemark. The total scores were also better for the defects treated with rhBMP-2 than for the untreated defects, but in no instance was the repair tissue identical to normal articular cartilage. The thickness of the cartilage in the defects treated with rhBMP-2 was 70 percent that of the normal cartilage, an observation that was identical to that at twenty-four weeks postoperatively. Immunostaining demonstrated significantly less type-I collagen in the defects treated with rhBMP-2 than in the untreated defects. Immunostaining for other matrix components showed no difference among the treatment groups. The mean residence time of rhBMP-2 in the cartilage defects was eight days with an elimination half-life of 5.6 days. Detectable amounts of rhBMP-2 were present as long as fourteen days after implantation. CONCLUSIONS: The problems associated with operative repair of cartilage include the formation of fibrocartilage rather than normal articular cartilage and the degeneration of that repair tissue over time. Our results demonstrate that the addition of rhBMP-2 to the operative site after creation of a full-thickness defect results in an improvement in the histological appearance and composition of the extracellular matrix at one year postoperatively. If these experimental results translate directly to the clinical situation, it is possible that the addition of rhBMP-2 to existing operative treatments for the repair of cartilage may improve the repair process and may help to maintain the integrity of the repair tissue.

Animals↗
PubMed2005

Identification of genes preferentially expressed in articular cartilage by suppression subtractive hybridization.

Suppression subtractive hybridization is very effective to enrich differentially expressed genes in two different tissues or cells. We therefore used the technique to identify characteristic genes expressed in rat knee joint articular cartilage as compared to rat costal cartilage. In this study, we revealed that several genes were enriched in a subtracted articular cartilage cDNA library. The most enriched gene is lubricin that is a putative key molecule for joint lubrication. The second gene is milk fat globule epidermal growth factor (EGF) factor 8, MFG-E8 whose expression has never been observed in cartilage. Other enriched genes are known to be expressed in cartilage, however their differential expressions in cartilages have not been necessarily common. The preferential expression of characteristic genes in articular cartilage would provide unique properties to the tissue. Our findings will provide a new view of articular cartilage.

Animals↗
PubMed1989

The effect of tumor necrosis factor alpha and gamma-interferon on the resorption of human articular cartilage and on the production of prostaglandin E and of caseinase activity by human articular chondrocytes.

In cultured human articular chondrocytes, addition of tumor necrosis factor alpha (TNF alpha) stimulated caseinase activity over the range of 10(-11) M to 10(-7) M and stimulated prostaglandin E (PGE) production over the range of 10(-10) M to 10(-7) M. Maximal stimulation was observed at 10(-8)M TNF alpha for both activities. Gamma-interferon (gamma-IFN) had a variable effect on PGE production and no significant effect on caseinase activity in articular chondrocyte cultures over a concentration range of 0.1-1,000 units/ml. Co-incubation of TNF alpha with gamma-IFN enhanced PGE production and decreased caseinase activity. Concentrations as low as 1 unit/ml of gamma-IFN had significant effects on TNF-stimulated production of PGE and on caseinase activity. Resorption of human articular cartilage was stimulated by TNF alpha (10(-7) M) and was inhibited by gamma-IFN (1,000 units/ml). It is possible that cartilage breakdown in vivo may be modulated by such interactions between cytokines.

Cartilage, Articular↗
PubMed1985

The organization of collagen in cryofractured rabbit articular cartilage: a scanning electron microscopic study.

Adult rabbit articular cartilage was prepared for scanning electron microscopy using, in order, glutaraldehyde fixation, enzymatic removal of proteoglycan, dehydration in ethanol, cryofracture in liquid nitrogen, and critical-point drying. Enzymes were effective in fixed material. Fixation, cryofracture, alignment of fracture surfaces with "split lines," and retention of subchondral bone were found to be necessary steps for the preservation of collagen detail. The fibrous framework was found to be similar to that proposed by Benninghoff and favored by more recent phase-contrast microscopic studies. Vertical fibers extending from subchondral bone and a network of tangentially oriented superficial fibrils converge in the transitional zone. No random layer is seen. Pericellular capsules interdigitate with the vertical fibers. When cartilage is prepared in a manner that minimizes tissue damage, scanning electron microscopy provides useful, unique information.

Animals↗
PubMed1987

Streaming potentials: a sensitive index of enzymatic degradation in articular cartilage.

Under physiological conditions, the extracellular matrix of articular cartilage contains a high fixed-charge density, associated with its ionized proteoglycan (PG) molecules. Compression of the highly charged cartilage matrix within the physiologic range leads to the production of electrical streaming potentials. We observed significant changes in the potential response due to chemical modifications of the matrix, such as extraction of PG and glycosaminoglycan (GAG) moieties using chondroitinase-ABC adn trypsin. The streaming potential was a sensitive index of the degradative loss of these matrix constituents and of the kinetics of the enzymatic degradative process.

Animals↗
PubMed1984

Degradation of articular cartilage by copper and hydrogen peroxide.

When porcine articular cartilage particles were incubated in the presence of Cu2+ and H2O2 at pH 7.4, solubilization of collagen and proteoglycan was observed. Both agents were necessary and the rate of solubilization was concentration dependent. Other transition metal ions showed much lower catalytic activity. The solubilized polypeptides were polydispersed in size and the hydroxyproline content of the larger fragments was 13% by weight. Further incubation of the released material with Cu2+ and H2O2 resulted in further degradation and partial destruction of hydroxyproline residues. Competitive studies with scavengers of OH X and 1O2 as well as the effect of D2O excluded these two species as major mediators in this system.

Animals↗
PubMed1994

Crystals in equine articular cartilage.

Crystal deposits have been observed in equine articular cartilage and identified by scanning electron microscopy and X-ray diffraction as octacalcium phosphate and calcium pyrophosphate dihydrate. Of 89 equine fetlock joints examined 10 contained evidence of calcification visible by eye. It is suggested that the deposition of crystals may be a mediator of arthritis in horses and may also cause damage directly.

Animals↗
PubMed1994

Responses of articular cartilage explant cultures to different oxygen tensions.

Bovine articular cartilage explants were cultured under atmospheres of 6, 10, 24, 66 and 91% oxygen. [35S]Glycosaminoglycan, chondroitin sulphate and keratan sulphate synthesis were measured together with the pool size of UDP-N-acetylhexosamines, UDP-hexoses and UDP-glucuronate. UDP-xylose was not detected. [35S]Glycosaminoglycan synthesis was maintained at the same level as in fresh tissue when cultured over 7 days with 20% foetal calf serum present and under a 6% oxygen tension. Under normal atmosphere (24%) synthesis was stimulated and remained elevated throughout the incubation period. Under higher oxygen tensions, initial stimulation of glycosaminoglycan synthesis was followed by progressive inhibition. The [35S]chondroitin sulphate/keratan sulphate ratio was constant (approximately 16:1) between 6 and 24% oxygen tension, but increased to 50:1 at 91% oxygen. The UDP-N-acetylhexosamine pool was larger under anaerobic (6, 10%) and excessively aerobic (66, 91%) oxygen tensions than under a normal atmosphere (24%). The UDP-hexose pool was expanded under anaerobic conditions. The UDP-glucuronate pool showed little variation between 6 and 24% oxygen tensions, but contracted under very aerobic conditions. We found no evidence indicating that keratan sulphate synthesis was favoured under anaerobic conditions to compensate for decreasing chondroitin sulphate synthesis.

Animals↗
PubMed1983

The use of caesium sulphate density gradient centrifugation to analyse proteoglycans from human articular cartilages of different ages.

Proteoglycan subunits from human articular cartilage were fractionated by caesium sulphate density gradient centrifugation. A single heterogeneous population of molecules was produced whose average density decreased with increasing age of the individual from which they were obtained. At no density did the carbohydrate composition of any adult fraction resemble that of any newborn fraction, although there was considerable overlap in density. However, there was a similarity in amino acid composition between the most dense proteoglycans from the adult and those of least density from the newborn. The carbohydrate content of a 2-year-old proteoglycan was intermediate in composition, with high density fractions resembling the newborn and low density fractions resembling the adult. In addition, the proteoglycans of lowest density in both the newborn and two year preparations showed additional bands on agarose/polyacrylamide gel electrophoresis resembling the adult material. These results indicate that while a core protein of adult composition may occur in the juvenile proteoglycan it need not necessarily be glycosylated in an adult manner, suggesting that glycosylation is to some extent independent of the origin of core protein heterogeneity.

Aging↗
PubMed1987

Purification and characterization of a serine proteinase inhibitor from human articular cartilage.

An inhibitor of serine proteinases from human articular cartilage was purified to homogeneity by sequential ultrafiltration and ion exchange chromatography on CM-Sephadex C-50. The apparent molecular weight of the cationic glycoprotein (pI greater than 10) was determined to be 16.5 X 10(3) by SDS gel electrophoresis. The inhibitor blocked the activity of leukocyte elastase, cathepsin G and trypsin but not leukocyte collagenase. In kinetic studies for the interactions with leukocyte elastase a firm enzyme-inhibitor binding was obtained. Amino acid analyses did not reveal homologies with other serine proteinase inhibitors already purified from human tissues.

Amino Acids↗
PubMed1995

NMR studies of the action of hypochlorous acid on native pig articular cartilage.

The action of sodium hypochlorite on pig articular cartilage was studied by 1H-NMR spectroscopy to model some aspects of degradation processes of cartilage during rheumatoid arthritis. Two effects of NaOCl on cartilage polysaccharides have been observed. Hypochlorous acid causes an enhanced release of oligomeric polysaccharides from cartilage. The second effect concerns the degradation of N-acetyl side chains of carbohydrates to acetate via a chlorinated transient product. Signal intensities for N-acetyl groups (approximately 2.0 ppm) increase during the first 2 h of incubation of cartilage with NaOCl. Then they decrease again. However, acetate (1.90 ppm) as the final product of degradation of N-acetyl side chains increases continuously over the period of incubation with NaOCl. In addition to polysaccharides, effects of NaOCl were only observed in cartilage samples on amino acids like alanine. The alanine resonance disappeared already at NaOCl concentrations where only small effects on cartilage polysaccharides have been observed.

Animals↗
PubMed2004

Determination of Poisson's ratio of articular cartilage by indentation using different-sized indenters.

Articular cartilage is often characterized as an isotropic elastic material with no interstitial fluid flow during instantaneous and equilibrium conditions, and indentation testing commonly used to deduce material properties of Young's modulus and Poisson's ratio. Since only one elastic parameter can be deduced from a single indentation test, some other test method is often used to allow separate measurement of both parameters. In this study, a new method is introduced by which the two material parameters can be obtained using indentation tests alone, without requiring a secondary different type of test. This feature makes the method more suitable for testing small samples in situ. The method takes advantages of the finite layer effect. By indenting the sample twice with different-sized indenters, a nonlinear equation with the Poisson's ratio as the only unknown can be formed and Poisson's ratio obtained by solving the nonlinear equation. The method was validated by comparing the predicted Poisson's ratio for urethane rubber with the manufacturer's supplied value, and comparing the predicted Young's modulus for urethane rubber and an elastic foam material with modulii measured by unconfined compression. Anisotropic and nonhomogeneous finite-element (FE) models of the indentation were developed to aid in data interpretation. Applying the method to bovine patellar cartilage, the tissue Young's modulus was found to be 1.79 +/- 0.59 MPa in instantaneous response and 0.45 +/- 0.26 MPa in equilibrium, and the Poisson's ratio 0.503 +/- 0.028 and 0.463 +/- 0.073 in instantaneous and equilibrium, respectively. The equilibrium Poisson's ratio obtained in our work was substantially higher than those derived from biphasic indentation theory and those optically measured in an unconfined compression test. The finite element model results and examination of viscoelastic-biphasic models suggest this could be due to viscoelastic, inhomogeneity, and anisotropy effects.

Animals↗
PubMed1980

Human joint performance and the roughness of articular cartilage.

It is known that the surface of articular cartilage is rough and it has been suggested that this is likely to affect the lubrication of human joints. This paper describes the direct measurement of a cartilage surface with a stylus instrument. It is found that the height distribution is Gaussian with an inverse-square power spectrum. It is thus possible to calculate the elastic deflection of the surface under normal walking loads and it is shown that the mean separation of the cartilage surfaces in a human joint varies rather slowly with load. In one particular hip joint at heel strike the real area of contact was calculated to be about 1.3 cm2, the mean gap to be about 60 micrometers and the trapped volume to be about 80 percent of that when standing.

Adult↗
PubMed1982

Characterisation of human articular cartilage link proteins from normal and osteoarthritic cartilage.

Proteoglycan link proteins were isolated from human articular cartilage obtained from normal and osteoarthritic femoral heads and purified to homogeneity employing a method previously described by this laboratory. The link proteins were analysed for amino acid composition, molecular weight on sodium dodecyl sulphate polyacrylamide gels, and ability to stabilise proteoglycan aggregates. The results of these studies were compared with those obtained with bovine link proteins. Two link proteins were identified in the purified fraction from normal and osteoarthritic human cartilage with apparent molecular weights of 54 000 (link 1) and 48 000 (link 2). Functionally the link proteins, isolated from osteoarthritic and normal cartilage, were indistinguishable as measured by their ability to stabilise aggregate. The amino acid compositions of normal and osteoarthritic link proteins were also found to be similar to each other but significantly different from the amino acid composition reported for the bovine link proteins. The quantities of these proteins in extracts from normal and diseased tissue were similar, as was the ratio of link protein 1 to link protein 2.

Aged↗
PubMed2005

Magnetic resonance imaging of articular cartilage: trauma, degeneration, and repair.

The assessment of articular cartilage using magnetic resonance imaging has seen considerable advances in recent years. Cartilage morphologic characteristics can now be evaluated with a high degree of accuracy and reproducibility using dedicated pulse sequences, which are becoming standard at many institutions. These techniques detect clinically unsuspected traumatic cartilage lesions, allowing the physician to study their natural history with longitudinal evaluation and also to assess disease status in degenerative osteoarthritis. Magnetic resonance imaging also provides a more objective assessment of cartilage repair to augment the information obtained from more subjective clinical outcome instruments. Newly developed methods that provide detail at an ultrastructural level offer an important addition to cartilage evaluation, particularly in the detection of early alterations in the extracellular matrix. These methods have created an undeniably important role for magnetic resonance imaging in the reproducible, noninvasive, and objective evaluation and monitoring of cartilage. An overview of the advances, current techniques, and impact of magnetic resonance imaging in the setting of trauma, degenerative arthritides, and surgical treatment for cartilage injury is presented.

Cartilage Diseases↗