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A comparative analysis of bone and cartilage metabolism in two strains of guinea-pig with varying degrees of naturally occurring osteoarthritis

Huebner, J.L. (author), Hanes, M.A. (author), Beekman, B. (author), TeKoppele, J.M. (author), Kraus, V.B. (author), Gaubius Instituut (author)

Objective: To evaluate the interaction of bone and cartilage in knee osteoarthritis (OA) pathogenesis in two guinea-pig strains with appreciable differences in bone metabolism. Design: Two guinea-pig strains were evaluated for their susceptibilities to OA using semi-quantitative histological grading of knee joints and quantification of...

article 2002

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Influence of development and joint pathology on stromelysin enzyme activity in equine synovial fluid

TNO Preventie en Gezondheid (author), Brama, P.A.J. (author), TeKoppele, J.M. (author), Beekman, B. (author), van El, B. (author), Barneveld, A. (author), van Weeren, P.R. (author)

Objective - To investigate the role of stromelysin (MMP-3) activity in synovial fluid (SF) at different stages of development and in common joint disorders in the horse. Methods - Stromelysin activity was determined with a fluorogenic enzyme activity assay in SF of normal joints of fetal, juvenile and adult horses, and in SF of horses suffering...

article 2000

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Urokinase-mediated fibrinolysis in the synovial fluid of rheumatoid arthritis patients may be affected by the inactivation of single chain urokinase type plasminogen activator by thrombin

Gaubius Instituut TNO (author), Braat, E.A.M. (author), Jie, A.F.H. (author), Ronday, H.K. (author), Beekman, B. (author), Rijken, D.C. (author)

Background - Excessive fibrin deposition within the inflamed joints of rheumatoid arthritis (RA) patients suggests that local fibrinolysis is inefficient, which seems to be in contrast with the observed increased levels of urokinase type plasminogen activator (u-PA). Thrombin-mediated inactivation of single chain u-PA (scu-PA) into an inactive...

article 2000

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Fluorogenic MMP activity assay for plasma including MMPs complexed to α2-macroglobulin

Beekman, B. (author), Drijfhout, J.W. (author), Ronday, H.K. (author), TeKoppele, J.M. (author), Gaubius instituut TNO (author)

Elevated MMP activities are implicated in tissue degradation in, e.g., arthritis and cancer. The present study was designed to measure MMP enzyme activity in plasma. Free active MMP is unlikely to be present in plasma: upon entering the circulation, active MMP is expected to be captured by the proteinase inhibitor α2-macroglobulin (α2M)....

article 1999

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Fluorogenic activity assays for MMP-3 and MMP-I in synovial fluid.

Beekman, B. (author), van El, B. (author), Drijfhout, J.W. (author), TeKoppele, J.M. (author)

article 1999

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Doxycycline inhibits collagen synthesis by differentiated articular chondrocytes.

TeKoppele, J.M. (author), Beekman, B. (author), Verzijl, N. (author), Koopman, J.L. (author), de Groot, J. (author), Bank, R.A. (author), Gaubius Instituut TNO (author)

Doxycycline (DOX) profoundly inhibited collagen synthesis by differentiated articular chondrocytes. At 25 microM, the rate of collagen synthesis was suppressed by more than 50% without affecting cell proliferation (DNA levels) and general protein synthesis (35S-Met and 35S-Cys incorporation). Steady-state mRNA levels of type II collagen were...

article 1998

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Matrix degradation by chondrocytes cultured in alginate: IL-1β induces proteoglycan degradation and proMMP synthesis but does not result in collagen degradation

Beekman, B. (author), Verzijl, N. (author), de Roos, J.A.D.M. (author), TeKoppele, J.M. (author), Instituut voor Verouderings- en Vaatziekten Onderzoek TNO (author)

Objective: To determine the role of interleukin-1β (IL-1β) in the degradation of proteoglycans and collagen by articular chondrocytes. Design: Chondrocytes were cultured in alginate beads for 2 weeks to produce extracellular matrix, followed by the addition of IL-1β for 1 or 2 days. Breakdown of extracellular matrix (with and without activation...

article 1998

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Articular chondrocytes: synthesis and MMP-mediated degradation of extracellular matrix

TNO Preventie en Gezondheid (author), Beekman, B. (author)

doctoral thesis 1998

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Matrix metalloproteinase activity in equine synovial fluid: Influence of age, osteoarthritis, and osteochondrosis

Gaubius Instituut TNO (author), Brama, P.A.J. (author), TeKoppele, J.M. (author), Beekman, B. (author), van Weeren, P.R. (author), Barneveld, A. (author)

Objective - To investigate the influence of age, osteoarthritis (OA), and osteochondrosis (OC) on the matrix metalloproteinase (MMP) activity in the synovial fluid (SF) of equine joints. Methods - SF was collected from normal and osteoarthritic metacarpophalangeal joints (normal: 14 adult, 28 juvenile; OA: 22 adult). And from normal and...

article 1998

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A simplified measurement of degraded collagen in tissues: Application in healthy, fibrillated and osteoarthritic cartilage

Bank, R.A. (author), Krikken, M. (author), Beekman, B. (author), Stoop, R. (author), Maroudas, A. (author), Lafeber, F.P.J.G. (author), TeKoppele, J.M. (author)

article 1997

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Degenerated human articular cartilage at autopsy represents preclinical osteoarthritic cartilage: Comparison with clinically defined osteoarthritic cartilage

van Valburg, A.A. (author), Wenting, M.J.G. (author), Beekman, B. (author), TeKoppele, J.M. (author), Lafeber, F.P.G.J. (author), Bijlsma, J.W.J. (author)

article 1997

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Synthesis of collagen by bovine chondrocytes cultured in alginate; posttranslational modifications and cell-matrix interaction

Beekman, B. (author), Verzijl, N. (author), Bank, R.A. (author), Von Der Mark, K. (author), TeKoppele, J.M. (author), TNO Preventie en Gezondheid (author)

The extracellular matrix synthesized by articular chondrocytes cultured in alginate beads was investigated. Collagen levels increased sigmoidally with time and remained constant after 2 weeks of culture. The presence of cartilage-specific type II collagen was confirmed immunohistochemically. Predominantly type H collagen was present in the...

article 1997

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Pre-column derivatisation method for the measurement of glycosylated hydroxylysines of collagenous proteins

Bank, R.A. (author), Beekman, B. (author), Tenni, R. (author), Tekoppele, J.M. (author), Gaubius Instituut TNO (author)

Measurement of the glycosylated hydroxylysines galactosyl- and glucosylgalactosylhydroxylysine (GH and GGH) in combination with other amino acids has been based on ion-exchange chromatography followed by reaction with ninhydrin. Here, a rapid and sensitive high-performance liquid chromatographic method with fluorimetric detection has been...

article 1997

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Sensitive fluorimetric quantitation of pyridinium and pentosidine crosslinks in biological samples in a single high-performance liquid chromatographic run

Bank, R.A. (author), Beekman, B. (author), Verzijl, N. (author), de Roos, J.A.D.M. (author), Nico Sakkee, A. (author), Tekoppele, J.M. (author), TNO Preventie en Gezondheid (author)

A high-performance liquid chromatographic assay was developed for pyridinium crosslinks and pentosidine in mature collagen of a wide variety of connective tissue hydrolysates by a simple two-step isocratic assay using a reversed-phase column. The crosslinks (including the internal standard pyridoxine) were optimally detected by their native...

article 1997

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Doxycycline inhibits collagen synthesis by bovine chondrocytes cultured in alginate

Beekman, B. (author), Verzijl, N. (author), de Roos, J.A.D.M. (author), Koopman, J.L. (author), Tekoppele, J.M. (author), Leiden, Netherlands Gaubius Instituut TNO (author)

Doxycycline is known for its ability to inhibit matrix metalloproteinases (MMPs), a family of enzymes that play a role in cartilage breakdown in arthritides. Its prophylactic effect in reducing joint degradation in osteoarthritis is mainly attributed to this property. In this study, we show that doxycycline exhibits a profound inhibition of...

article 1997

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Modified proenzymes as artificial substrates for proteolytic enzymes: Colorimetric assay of bacterial collagenase and matrix metalloproteinase activity using modified pro-urokinase

Gaubius Instituut TNO (author), Verheijen, J.H. (author), Nieuwenbroek, N.M.E. (author), Beekman, B. (author), Hanemaaijer, R. (author), Verspaget, H.W. (author), Ronday, K.H. (author), Bakker, A.H.F. (author)

We describe a new principle for assessment of the activity of proteolytic enzymes of all classes and show the application of this principle for the quantitative assay of bacterial collagenase and human matrix metalloproteinases (MMPs). Central to this new principle is the presence of a proenzyme that can be activated into an active enzyme by a...

article 1997

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Highly increased levels of active stromelysin in rheumatoid synovial fluid determined by a selective fluorogenic assay

Gaubius Instituut TNO (author), Beekman, B. (author), van El, B. (author), Drijfhout, J.W. (author), Ronday, H.K. (author), TeKoppele, J.M. (author)

Stromelysin-1 (MMP-3) is an important member of the matrix metalloproteinase family. In joint-degrading diseases like arthritis, elevated levels of MMP-3 protein are detected in synovial fluid using immunological methods. However, these methods do not discriminate between active and inactive enzyme. In the present study, a specific stromelysin...

article 1997

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Amino acid analysis by reverse-phase high-performance liquid chromatography: Improved derivatization and detection conditions with 9-fluorenylmethyl chloroformate

Bank, R.A. (author), Jansen, E.J. (author), Beekman, B. (author), te Koppele, J.M. (author), Gaubius Instituut TNO (author)

article 1996

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Effect of IGF1 and TGFß2 on assembly of proteoglycans and collagen by cultured bovine articular chondrocytes

van Osch, G.J.V.M. (author), van den Berg, W.B. (author), te Koppele, J.M. (author), van der Kraan, P.M. (author), Beekman, B. (author), Homminga, G.N. (author), Häuselmann, H.J. (author), TNO Preventie en Gezondheid (author)

conference paper 1996

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Cleavage of collagen type I and II telopeptides by stromelysin is limited to the N-terminal telopeptide of collagen type II

Böhm, B.B. (author), Beekman, B. (author), Drijfhout, J.W. (author), te Koppele, J.M. (author), Gaubius Instituut TNO (author)

conference paper 1996