bluuebunny/crossref_metadata_2025_split huggingface dataset:
Basic fibroblast growth factor stimulates articular cartilage enlargement in young rats in vivo
Authors: Shida Jun‐Ichi , Jingushi Seiya , Izumi Toshihiro , Iwaki Akira , Sugioka Yoichi 
Published: February 2005

AbstractBasic fibroblast growth factor is a potent mitogen for chondrocytes and influences the protein synthesis of their extracellular matrix in vitro. To investigate its effect on normal developing articular cartilage in vivo, we injected basic fibroblast growth factor once into the knee joints of 4‐week‐old rats. Phosphate buffered saline was similarly injected into the contralateral knee joints as controls. A histological analysis showed that an injection of basic fibroblast growth factor induced enlargement of the articular cartilage area, especially in the condylar ridge region on day 7 after the injection. The extent of the enlargement was dose‐dependent. The localization and amount of proliferating cells in the articular cartilage were analyzed immunohistochemically by the detection of proliferating cell nuclear antigen. On day 1 after the injection, the number of cells positive for proliferating cell nuclear antigen increased significantly in the joints that were injected compared with the controls, and Northern blot analysis showed that the level of messenger RNA for α(II) procollagen was lower in these joints than in the controls. The message in the joints that had been injected increased on day 7, and it was greater than that in the controls. This suggests that proliferating chondrocytes in developing articular cartilage respond to basic fibroblast growth factor with a resulting proliferation of chondrocytes followed by enlargement of cartilage.
Articular chondrocyte tenascin‐C production and assembly into de Novo extracellular matrix
Authors: Savarese J. J. , Erickson H. , Scully S. P. 
Published: February 2005

AbstractTenascin‐C is an oligomeric glycoprotein of the extracellular matrix that is expressed in a variety of processes including development, tissue remodeling, wound healing, cell adhesion/antiadhesion, and cell/matrix interactions. Tenascin has recently been acknowledged as a component of the extracellular matrix of articular cartilage, but its function remains unclear. In this study, bovine articular chondrocytes were grown in alginate beads for 35 days to examine the kinetics of tenascin synthesis and incorporation into de novo extracellular matrix. During the culture period, 6 harvest days were established in which culture medium was recovered, alginate beads were dissociated with an EDTA solution, and chondrocytes were collected and lysed by sonication. Total DNA determination performed on the cell lysates demonstrated chondrocyte survival and proliferation. Western blotting performed on the medium, EDTA/alginate, and lysate samples demonstrated the production of both the 220 and 320 kDa tenascin size variants and their differential compartmentalization within the culture system. Tenascin was incorporated into the alginate bead matrix at a constant rate of 3.8 μg/day. The 320 kDa variant was produced in higher quantity, but the 220 kDa fragment was twice as likely to be incorporated into the de novo matrix. Methylene blue/acid fuchsin staining and tenascin immunohistochemistry demonstrated the incorporation of tenascin into a progressively expanding matrix surrounding the chondrocytes. The results suggest a role for tenascin in the assembly of the chondrocyte matrix and as a soluble mediator of chondrocytes with possible diverse functions for the tenascin size variants.
Anterior glenohumeral stabilization factors: Progressive effects in a biomechanical model
Authors: Malicky David M. , Soslowsky Louis J. , Blasier Ralph B. , Shyr Yu 
Published: February 2005

AbstractThe aim of this study was to evaluate the anterior stabilizing factors of the glenohumeral joint over a range of translations. The stabilizers examined included the capsular ligaments, the coracohumeral ligament, the rotator cuff muscles and the long head of the biceps. Simulated muscle forces were applied to eight shoulder specimens to produce 90° of total elevation of the arm in the scapular plane. Stability, defined as the force required to reach a specified subluxation, then was evaluated under varying configurations of capsule cuts, humeral rotation, and muscular loads. The overall force‐displacement relationship of the subluxation was found to increase exponentially in external rotation to 239 N at 10 mm of displacement and to level off in neutral rotation to 172 N at 10 mm of displacement. Among the muscles, the biceps was the most important stabilizer in neutral rotation, providing more than 30 N of stabilization: the subscapularis provided the greatest degree of stabilization in external rotation, increasing to approximately 20 N. The subscapularis and supraspinatus were the most consistently important stabilizers in both types of rotation. In external rotation, the superior, middle, and inferior glenohumeral ligaments were the most effective ligamentous stabilizers, and all provided progressively more stabilization as higher displacements were reached. The stability provided by some of the ligaments reached nearly 50 N at 10 mm of displacement.
Activating mutations of Gs protein in monostotic fibrous lesions of bone
Authors: Alman Benjamin A. , Greel Debra A. , Wolfe Hubert J. 
Published: February 2005

AbstractActivating mutations of the alpha chain of the heterotrimeric signal transducer Gs disrupt the inherent guanosine triphosphatase activity of the alpha chain, stimulate adenylyl cyclase, and can result in independent cell proliferation. Such mutations are identified in a number of endocrine disorders, including McCune‐Albright syndrome, which is a triad of endocrinopathy, café au lait spots, and polyostotic fibrous dysplasia. The mutation in this syndrome is a missense point mutation in exon 8 that results in the substitution of either histidine or cysteine for arginine at position 201. Monostotic fibrous dysplasia is a nonhereditary isolated bone lesion. Other isolated bone lesions that share some cytologic and clinical similarities to fibrous dysplasia are osteofibrous dysplasia and aggressive fibromatosis involving bone. Four cases of monostotic fibrous dysplasia, four cases of aggressive fibromatosis involving bone, and one case of osteofibrous dysplasia were studied to determine if a mutation was present in exon 8 of the alpha chain of Gs. A missense mutation was present in all of the fibrous dysplasias. The other fibrous lesions and uninvolved tissue did not contain a mutation. Somatic activating mutations of Gs differentiate fibrous dysplasia from the other lesions and may be responsible for the loss of control of local proliferation and growth factor expression.
Effect of human adrenomedullin on vascular resistance of the canine tibia
Authors: Kato Teiji , Bishop Allen T. , Wood Michael B. , Adams Mary L. 
Published: February 2005

AbstractAn ex vivo model of a perfused canine tibia was used to investigate the effect of human adrenomedullin, a novel peptide with known vasodilator properties, on the vascular resistance of bone. Human adrenomedullin has a potent and long‐lasting vasodilator effect in the canine tibia following precontraction of vascular smooth muscle by infusion of prostaglandin F2α. A 0.1 ml bolus injection of 10−5 M human adrenomedullin suppressed the pressor response of the canine tibia preparation to an infusion of norepinephrine by 43–52% for a duration of 100 minutes. An injection of 10−6 adrenomedullin suppressed the pressor response to an infusion of norepinephrine by 22–23% for a duration of 40 minutes. These data suggest that human adrenomedullin may be a potent and long‐acting vascular smooth‐muscle relaxant in bone.
Effect of link protein concentration on articular cartilage proteoglycan aggregation
Authors: Tang Lih‐Heng , Buckwalter Joseph A. , Rosenberg Lawrence C. 
Published: February 2005

AbstractPrevious work has shown that alterations in proteoglycan aggregates are among the first changes detected with aging, disuse, and degeneration of articular cartilage, yet the cause or causes of these alterations remain unknown. To determine if differences in link protein concentration can explain alterations in the assembly, size, and stability of articular cartilage proteoglycan aggregates, we isolated proteoglycan monomer (aggrecan) and link protein from adult bovine articular cartilage and then assembled proteoglycan aggregates from aggrecan and 0.8% hyaluronan relative to aggrecan weight, in the presence of 0, 2, 4, 6, 8, 10, 15, and 20% concentrations of link protein relative to aggrecan weight. We determined the amount, sedimentation coefficient, and stability of the aggregates by analytical ultracentrifugation and measured their dimensions by electron microscopy with use of the monolayer technique. Increased aggregate size, as determined by ultracentrifugation, was directly correlated with an increased number of aggrecans per aggregate and with increased hyaluronan length, as determined by electron microscopy. The concentration of link protein significantly influenced aggregation: concentrations of 6–8% produced maximum aggregation, aggregate stability, and uniformity of aggrecan spacing; concentrations greater than 10% led to the formation of superaggregates (aggregates with sedimentation velocities greater than 100 S that may result from linking two or more hyaluronan filaments) but decreased aggregate stability; and concentrations of less than 4% link protein significantly decreased aggregation, the size and stability of aggregates, and the regularity of aggrecan spacing. The latter observations suggest that a decline in the concentration of link protein could decrease the organization and stability of the articular cartilage matrix.
Transforming growth factor‐β1 enhances bone healing to unloaded tricalcium phosphate coated implants: An experimental study in dogs
Authors: Lind Martin , Overgaard Søren , Søballe Kjeld , Nguyen Tue , Ongpipattanakul Boonsri , Bünger Cody 
Published: February 2005

AbstractGrowth of bone into cementless prosthetic components is compromised after revision of failed joint prostheses and by osteoporosis, gaps, and micromotion. We studied the effects of recombinant human transforming growth factor‐β1 adsorbed on ceramic coated implants on the improvement of mechanical fixation and bone growth on the implant. Unloaded cylindrical grit‐blasted titanium alloy implants were inserted bilaterally into both the medial and lateral femoral condyles of 10 skeletally mature mongrel dogs. The implants measured 10 mm in length and 6 mm in diameter and were initially surrounded by a 2 mm gap. One implant had an uncoated titanium surface and three implants were coated with tricalcium phosphate and 0, 0.3, or 3.0 μg of recombinant human transforming growth factor‐β1. The dogs were killed at 6 weeks. Mechanical testing showed a 3‐fold increase in fixation for the 0.3 μg dose of recombinant human transforming growth factor‐β1 and a 2‐fold increase for the 3.0 μg dose. Histological analysis of bone growth on the implant demonstrated that maximal stimulation occurred with the 0.3 μg dose, but bone volume in the gap was maximally stimulated by the 3.0 μg dose and increased 2‐fold over control values. The majority of tricalcium phosphate was resorbed after the 6‐week observation period. This study suggests that recombinant human transforming growth factor‐β1 adsorbed onto implants coated with tricalcium phosphate ceramic can enhance mechanical fixation and bone growth on the implant. The use of transforming growth factor‐β1 on ceramic coated prosthetic components may help to improve the functional outcome of cementless total joint replacements.
Expression of syndecan‐3 and tenascin‐C: Possible involvement in periosteum development
Authors: Koyama Eiki , Shimazu Atsushi , Leatherman Judith L. , Golden Eleanor B. , Nah Hyun‐Duck , Pacifici Maurizio 
Published: February 2005

AbstractThe development of cartilaginous elements of long bone during embryogenesis and postnatal bone repair processes is a complex process that involves skeletal cells and surrounding mesenchymal periosteal cells. Relatively little is known of the mechanisms underlying these processes. Previous studies from this and other laboratories have suggested that the extracellular matrix protein tenascin‐C is involved in skeletogenesis. Using in situ hybridization and immunofluorescence, we extended those studies by comparing the expression of tenascin‐C with that of syndecan‐3, which belongs to a family of cell surface receptors with which tenascins are known to interact. We found that syndecan‐3 transcripts at first were very abundant in the presumptive periosteum surrounding the diaphysis of early chondrocytic skeletal elements in chick limb. As the elements developed further syndecan‐3 gene expression decreased in the diaphyseal periosteum, whereas it became stronger around the early epiphysis and within the forming articular cells. However, as the diaphyseal periosteum initiated osteogenesis and gave rise to the intramembranous bone collar, syndecan‐3 gene expression increased again. At early stages of skeletogenesis, the tenascin‐C gene exhibited patterns of expression that were similar to, and temporally followed, those of the syndecan‐3 gene. At later stages, however, tenascin‐C gene expression was markedly reduced during intramembranous osteogenesis around the diaphysis. In addition, although syndecan‐3 gene expression was low in osteoblasts and osteocytes located deep into trabecular bone, tenascin‐C gene expression remained strong. Thus, tenascin‐C and syndecan‐3 display distinct temporal and spatial patterns of expression in periosteum and during the development of long bone. Given their multidomain structure and specific patterns of expression, these macromolecules may regulate site‐specific skeletal processes, including interactions between developing periosteum and chondrocytes and delineation of the early cartilaginous skeletal elements.
Zone‐specific cell biosynthetic activity in mature bovine articular cartilage: A new method using confocal microscopic stereology and quantitative autoradiography
Authors: Wong M. , Wuethrich P. , Eggli P. , Hunziker E. 
Published: February 2005

AbstractA new methodology was developed to measure spatial variations in chondrocyte/matrix structural parameters and chondrocyte biosynthetic activity in articular cartilage. This technique is based on the use of a laser scanning confocal microscope that can “optically” section chemically fixed, unembedded tissue. The confocal images are used for morphometric measurement of stereologic parameters such as cell density (cells/mm3), cell volume fraction (%), surface density (1/cm), mean cell volume (μm3), and mean cell surface area (μm2). Adjacent pieces of tissue are simultaneously processed for conventional liquid emulsion autoradiography, and a semiautomated grain counting program is used to measure the silver grain density at regions corresponding to the same sites used for structural measurements. An estimate of chondrocyte biosynthetic activity in terms of grains per cell is obtained by dividing the value for grain density by that for cell density. In this paper, the newly developed methodology was applied to characterize the zone‐specific behavior of adult articular cartilage in the free‐swelling state. Cylinders of young adult bovine articular cartilage were labelled with either [3H]proline or [35S]sulfate, and chondrocyte biosynthesis and structural parameters were measured from the articular surface to the tidemark. The results showed that chondrocytes of the radial zone occupied twice the volume and surface area of the chondrocytes of the superficial zone but were 10 times more synthetically active. This efficient and unbiased technique may prove useful in studying the correlation between mechanically induced changes in cell form and biosynthetic activity within inhomogeneous tissue as well as metabolic changes in cartilage due to ageing and disease.
Topographic variation in biglycan and decorin synthesis by articular cartilage in the early stages of osteoarthritis: An experimental study in sheep
Authors: Little C. B. , Ghosh P. , Bellenger C. R. 
Published: February 2005

AbstractArticular cartilage contains large molecular weight proteoglycans that aggregate with hyaluronic acid (aggrecan) and small species, particularly biglycan (dermatan sulphate proteoglycan‐1) and decorin (dermatan sulphate proteoglycan‐2). that do not. Mechanical stresses have been shown to profoundly influence the metabolism of aggrecan by articular chondrocytes; however, there are limited corresponding data on the metabolism of dermatan sulphate proteoglycans 1 and 2. The objective of this study was to examine the metabolism of aggrecan, biglycan, and decorin in articular cartilage from different weight‐bearing areas of normal ovine stifle joints and in joints 6 months after meniscectomy, a procedure that has been shown to induce early osteoarthritic changes. [35S]proteoglycans synthesised by cartilage explants from eight different weight‐bearing regions of unoperated and meniscectomised ovine stifle joints during 48 hours of culture were separated by size‐exclusion chromatography, hydrophobic chromatography, and sodium dodecyl sulfatepolyacrylamide gel electrophoresis and were quantitated by phosphor‐screen autoradiography. The synthesis and degradation of the proteoglycans were expressed relative to the DNA content of the explants. In control joints, the cartilage exposed to high contact stress synthesised significantly less proteoglycan overall and more decorin than joint regions bearing less stress. Explants from high stress regions also released significantly greater amounts of resident proteoglycans (dimethylmethylene blue positive) into media during culture. After lateral meniscectomy, the lateral tibial and femoral cartilages showed elevated biosynthesis of both 35S‐dermatan sulphate proteoglycans 1 and 2. This chondrocyte biosynthetic response was accompanied by increased catabolism of aggrecan and the release of its degradation products into culture media. These experiments revealed, in normal joints, a topographic variation in proteoglycan synthesis by articular cartilage that was related to the mechanical stress to which the tissues were subjected in vivo. This biosynthetic pattern changed when the load distribution of the joint was altered by unilateral meniscectomy. These data suggest that an altered chondrocyte phenotypic expression of proteoglycans in response to abnormal mechanical loading is an early event in osteoarthritis.
Role of aspartate in ischemic spinal cord damage
Authors: Ogata T. , Nakamura Y. , Tsuji K. , Okumura H. , Kataoka K. , Shibata T. 
Published: February 2005

AbstractTo study the potentially different roles of the excitatory amino acids glutamate and aspartate in the development of ischemic injury of the spinal cord, we measured their release from cultured neurons and glial cells under ischemic conditions. We also examined changes in intracellular Ca2+ concentration and the damage elicited in cultured neurons by glutamate and aspartate. Hypoxic‐hypoglycemic treatment (in vitro ischemia) elicited a rapid release of the excitatory amino acids from cultured spinal cord neurons and glial cells, but the release was greater from glial cells than from neurons. The ischemia‐induced glutamate release from glial cells was transient: the aspartate release lasted longer, although the peak level was smaller than that of glutamate. In cultured neurons, a remarkable elevation in intracellular Ca2+ concentration was induced by glutamate but not by a lower concentration (10 μM) of aspartate, which is below the neurotoxic dose. At the higher concentration (100 μM), both excitatory amino acids induced a marked elevation in intracellular Ca2+ concentration and neuronal death. These results indicate that aspartate is less potent than glutamate in eliciting excitatory neurotransmission under normal physiological conditions. However, under pathological conditions such as ischemia, the increased release of aspartate from glial cells may add to the damage to neighboring neurons.
Primary immunolocalization of estrogen and progesterone target cells in the human anterior cruciate ligament
Authors: Liu Stephen H. , Al‐Shaikh Raad , Panossian Vahé , Yang Rong‐Sen , Nelson Scott D. , Soleiman Neptune , Finerman Gerald A. M. , Lane Joseph M. 
Published: February 2005

AbstractTo identify estrogen and progesterone target cells in the human anterior cruciate ligament, immunohistochemical localization of both estrogen and progesterone receptors was performed in 17 specimens of human anterior cruciate ligament. All ligament specimens were obtained at surgery. Thirteen specimens were from women, and four were from men: the average age was 57 years (range, 18–78 years). Eleven specimens (from nine women and two men) came from total knee replacements for osteoarthritis of the knee; three (from two women and one man). from reconstructions of the anterior cruciate ligament; two (both from women). from medial meniscectomies: and one (from a man), from an amputation secondary to chondrosarcoma of the pelvis. An immunoperoxidase method using monoclonal antibodies to the estrogen and progesterone receptors was employed to identify estrogen and progesterone target cells in the anterior cruciate ligament. Staining of both receptors was demonstrable in 14 specimens, and in the remaining three specimens less than 15% of the cells were stained. Both estrogen and progesterone receptors were localized to synoviocytes in the synovial lining, fibroblasts in the anterior cruciate ligament stroma, and cells in the blood vessel walls of the ligament. This demonstration of receptors for estrogen and progesterone in the cells of anterior cruciate ligament suggests that female sex hormones may have an effect on its structure and composition.