The application of an indenter system to measure structural properties of articular cartilage in the horse. Suitability of the instrument and correlation with biochemical data.

A recently developed indenter system that aims at determination of local structural properties of the cartilage surface was evaluated for suitability in the horse. To this aim, maximum indenter force was measured of the articular surface and related to biochemical characteristics of the cartilage at different sites of the distal metacarpal bone (MC). Significant topographical variation exists in structural properties of the articular surface of the MC.

Eotaxin induces degranulation and chemotaxis of eosinophils through the activation of ERK2 and p38 mitogen-activated protein kinases.

Eotaxin and other CC chemokines acting via CC chemokine receptor-3 (CCR3) are believed to play an integral role in the development of eosinophilic inflammation in asthma and allergic inflammatory diseases. However, little is known about the intracellular events following agonist binding to CCR3 and the relationship of these events to the functional response of the cell. The objectives of this study were to investigate CCR3-mediated activation of the mitogen-activated protein (MAP) kinases extracellular signal-regulated kinase-2 (ERK2), p38, and c-jun N-terminal kinase (JNK) in eosinophils and to assess the requirement for MAP kinases in eotaxin-induced eosinophil cationic protein (ECP) release and chemotaxis.

Use of recombinant human osteogenic protein-1 for the repair of subchondral defects in articular cartilage in goats.

The objective of this pilot study was to examine in vivo the potential of recombinant human osteogenic protein-1 (rhOP-1, also called bone morphogenetic protein-7, BMP-7) for treatment of subchondral lesions by induction of new hyaline cartilage formation. Subchondral left knee defects in 17 mature goats were treated with fresh coagulated blood mixed with (1) rhOP-1 combined with collagen (OP-1 device, 400 microgram/mL); (2) rhOP-1 alone (OP-1 peptide, 200 microgram/mL); (3) OP-1 device with small particles of autologous ear perichondrium; (4) OP-1 peptide with small particles of autologous ear perichondrium; or (5) autologous ear perichondrium alone (controls). rhOP-1 was combined with either collagen (OP-1 device) or not (OP-1 peptide).

IgE levels in surgery: effect of ranitidine and prednisolone.

Background: Immunoglobulin E (IgE) is important in allergic reactions and in host defense against parasites. IgE may also participate in the acute-phase response to physical stress. This study aimed to determine whether major abdominal surgery induced increased serum IgE levels, and whether treatment with ranitidine or prednisolone influenced the IgE response to surgery.

Increase of decorin content in articular cartilage following running.

The effect of long distance running exercise (40 km/day for 15 weeks, five days a week) on the decorin content of articular cartilage from the knee joint was studied in female beagle dogs. Samples from load bearing sites on the lateral plateau of the tibia (TL), and pooled material from two minimum load bearing sites on the posterior section of lateral (FLP) and medial (FMP) femoral condyles were analyzed. The running exercise protocol did not lead to significant changes in the overall glycosaminoglycan content of the cartilage.

Histamine and tryptase in nasal lavage fluid following challenge with methacholine and allergen.

Background: The level of histamine in nasal lavage fluid has been used as an index of mast cell/basophil activation in a number of studies. Obviously, such an index can only be valid if changes in the secretory activity of nasal glands do not affect the level of histamine in lavage fluid (i.e.

A method for production and determination of histamine releasing activity from human peripheral blood mononuclear cells.

Histamine releasing factors, i.e. cytokines capable of inducing histamine release from basophils or mast cells, have been suggested to be involved in the pathogenesis of, for example, allergic late-phase reactions.

Cyclic loading is harmful to articular cartilage from which proteoglycans have been partially depleted by retinoic acid.

We studied whether cyclic loading is harmful to degraded cartilage. Sets of four cartilage-bearing sesamoid bones were dissected from 5-year old cows. One bone from each set was cultured for 17 h in control medium to serve as an ex vivo control.

Irreversible changes in glycosaminoglycan composition of anatomically intact bovine articular cartilage induced by intermittent loading.

The changes in matrix composition induced by I MPa intermittent (0.2 Hz) loading of anatomically intact bovine articular cartilage in vitro are studied. The kinetics of chondrocyte response was determined in experiments where sesamoid bones of adult cows were loaded for 0, 3, 5 and 7 days.

Transforming growth factor-beta stimulates retinoic acid-induced proteoglycan depletion in intact articular cartilage.

Cartilage-bearing sesamoid bones from the metacarpophalangeal joints of adult cows were cultured with retinoic acid for 1 week and allowed to recover in control medium for another 2 weeks. Retinoic acid decreased the proteoglycan synthesis of the cartilage to 33% of control values, and induced 26% loss of proteoglycans from the matrix. During recovery, the synthesis of proteoglycans returned to the control level but their content remained reduced.

Intermittent loading induces the expression of 3-B-3(-) epitope in cultured bovine articular cartilage.

Objective: To study the effects of intermittent loading on the proteoglycans synthesized in intact cultured articular cartilage.

Methods: Sesamoid bones carrying articular cartilage were subjected to cyclic loading in vitro for one week. A new procedure to fix and decalcify the tissue was developed and an immunohistochemical analysis of the expression of 3-B-3(-) epitope in the articular cartilage was carried out.

Modulation of proteoglycan composition in cultured anatomically intact joint cartilage by cyclic loads of various magnitudes.

The anatomically intact articular cartilage (area approximately 2.5 cm2) of 6-month-old bovine sesamoid bones was cyclically (0.3 Hz) loaded with 0, 5, 25 and 50 kg in vitro for 7 days.

Proteoglycan depletion of intact articular cartilage by retinoic acid is irreversible and involves loss of hyaluronate.

Intact sesamoid bones from bovine metacarpophalangeal joints were cultured with retinoic acid for 9 days and allowed to recover in control medium for up to 17 days. Retinoic acid (300 ng/ml) induced 91.8% inhibition of glycosaminoglycan (GAG) synthesis and 50.

Kinetics of proteoglycan turnover in bovine articular cartilage explants.

The turnover of proteoglycans was studied in explant cultures of mature bovine articular cartilage. The aim of the study was to compare the in vitro turnover rates of newly synthesized proteoglycans and endogenous proteoglycans. Cartilage was maintained in the presence of various serum concentrations in order to determine the conditions of steady-state proteoglycan metabolism.

Effects of loading on the synthesis of proteoglycans in different layers of anatomically intact articular cartilage in vitro.

The anatomically intact articular cartilage (approximately equal to 2.5 cm2) of whole bovine sesamoid bones was cultured on its bone support. A load of 5 kg was applied intermittently at 0.

Age related changes in the turnover of proteoglycans from explants of bovine articular cartilage.

Articular cartilage in explant culture synthesized 2 proteoglycan types of different size. The proportion of 35S-sulfate incorporated into the small proteoglycan was higher in mature (17%) than in immature cartilage (11%). The chondroitin sulfate chains of both proteoglycans, synthesized by mature cartilage were shorter than those of immature cartilage, with a higher ratio of 6-sulfated over 4-sulfated disaccharides.

Effect of temperature on the metabolism of proteoglycans in explants of bovine articular cartilage.

The turnover of proteoglycans in bovine articular cartilage was determined in explant cultures, maintained at 32 degrees C or 37 degrees C. Both the rate of proteoglycan synthesis and the release of newly synthesized proteoglycans were decreased in cultures incubated at 32 degrees C compared to 37 degrees C. At both temperatures the newly synthesized proteoglycans were similar in hydrodynamic size and chain length of the glycosaminoglycans.

Composition of proteoglycans synthesized in different layers of cultured anatomically intact articular cartilage.

Calf articular cartilage was cultured anatomically intact on its natural bone-support. At day 0 and day 7, respectively, the cartilage was radiolabeled, washed and harvested in 3 successive layers parallel to the articular surface. The proteoglycans were studied after extraction by 4 M guanidine hydrochloride.

Effect of nalidixic acid, pipemidic acid and cinoxacin on chondrocyte metabolism in explants of articular cartilage.

Explants of immature bovine articular cartilage were exposed to nalidixic acid, pipemidic acid and cinoxacin at one and ten times the human therapeutic plasma level for 7 days. Only nalidixic acid had significant effects on the chondrocyte metabolism. 20 micrograms/ml nalidixic acid caused an increase of 35S-sulfate incorporation into glycosaminoglycans at day 7.

Studies on the extraction of different proteoglycan populations in bovine articular cartilage.

Large proteoglycan monomers and small dermatan sulfate proteoglycans were extracted from explants of bovine articular cartilage with increasing (0-4 M) concentrations of guanidinium chloride (GuHCl). The first extractions were followed by a second extraction with 4 M GuHCl. The amount of proteoglycans extracted in the first buffer depended on the GuHCl concentration.

A Staphylococcus aureus factor exclusively removes large proteoglycan monomers from explants of articular cartilage.

Exposure of explants of viable, as well as freeze-thawed, bovine articular cartilage to culture filtrates of Staphylococcus aureus increased the release of proteoglycans from the tissue significantly within 24 h. The S. aureus factor exclusively releases the large, 4 M guanidinium extractable proteoglycans from the matrix; the small proteoglycans are not affected by this factor.

Bovine sesamoid bones: a culture system for anatomically intact articular cartilage.

Medial sesamoid bones from the metacarpophalangeal joints of calves were used for prolonged culture of anatomically intact articular cartilage on its natural bone support. The cartilage remained viable during culture, without signs of degeneration. After 1 wk of culture the cartilage showed an increased proteoglycan synthesis, and some minor changes in the composition of newly synthesized proteoglycans were observed.

Effect of sulfate concentration on glycosaminoglycan synthesis in explant cultures of bovine articular cartilage.

The effects of the sulfate- and FCS concentration on the rate of synthesis and the biochemical properties of glycosaminoglycans, synthesized in bovine articular cartilage in vitro, were studied. 20% FCS in the culture medium stimulated the rate of synthesis. In media without FCS, the rate of synthesis decends from day 0 on.