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T R Oegema

Publications and source records attributed to T R Oegema.

At least 19 recordsLinked to original sources
PubMed1997

The interaction of the zone of calcified cartilage and subchondral bone in osteoarthritis.

The zone of calcified cartilage (ZCC) forms an important interface between cartilage and bone for transmitting force, attaching cartilage to bone, and limiting diffusion from bone to the deeper layers of cartilage. The height of the ZCC is a relatively constant percent of articular cartilage and the height is maintained by a balance between progression of the tidemark into the unmineralized cartilage and changing into bone by vascular invasion and bony remodeling. During its formation, the cells that form the ZCC have properties similar to the cells of the growth plate. In the adult, the ZCC becomes quiescent but not inactive. The ZCC may be reactivated in osteoarthritis and may progressively calcify the unmineralized cartilage. This might contribute to cartilage thinning which would increase the concentration of forces across the uncalcified cartilage leading to more damage. Although the subchondral bony plate remodels extensively in osteoarthritis, there is little evidence that a change in the biomechanics of the plate directly initiates the osteoarthritic process in cartilage. However, increased repair by endochondral ossification of vertical cracks in the ZCC that penetrate into the marrow space could contribute to progression via changes in the ZCC.

Animals↗
PubMed1997

Mercuric salt-catalyzed removal of unsaturated glucuronic acid from chondroitinase-treated proteochondroitin sulfate.

Aggrecan (PG) was isolated from Swarm rat chondrosarcoma and the chondroitin 4-sulfate removed with chondroitinase ABC (ABC) or ACII (AC), leaving a 4-deoxy-beta-d-gluc-4-enuronosyl (DeltaGlcA) residue on the nonreducing terminus of the attached chondroitin sulfate chains. Mercuric acetate (as low as 5 mm) removed the DeltaGlcA from the PG-ABC within 10 min at 25 degrees C at pH 5.0, and the rate was pH independent between pH 3.0 and 5.0. The reaction was readily monitored by following the loss of reactivity to the monoclonal antibodies specific for 4-sulfated and nonsulfated unsaturated disaccharides in ELISA. After mercury treatment, there was a loss of carbazole-positive material and a decrease in the size of the linkage region oligosaccharides consistent with DeltaGlcA being removed. Aside from the loss of DeltaGlcA, neutral sugar composition and sialic acid content remained unchanged. After electrophoresis in a 4% polyacrylamide gel, Hg-treated PG-ABC and PG-AC migrated as single major bands, but with reduced mobilities, which is consistent with a loss of charge. There was a loss of reactivity to specific monoclonal antibodies. Treated aggrecan did not bind hyaluronic acid. This loss was not completely prevented by being present in a complex with link protein and hyaluronic acid. However, link protein could partially restore the hyaluronic acid interaction, so the effect of mercuric acetate on biological function will have to be assessed on an individual basis. Treatment with mercuric acetate is an effective, rapid, reproducible way of removing DeltaGlcA from both chondroitinase ABC and ACII-digested proteoglycan.

Aggrecans↗
PubMed1996

Reduction of brain injury using heparin to inhibit leukocyte accumulation in a rat model of transient focal cerebral ischemia. I. Protective mechanism.

Heparin has long been established as an anticoagulant. Although heparin has been demonstrated to reduce brain injury after ischemia and reperfusion, its mechanism of action remains unknown. Recent investigations reveal that it can modulate biological processes such as binding to adhesion receptors on endothelial cells and leukocytes. The authors hypothesized that heparin's protective effect is closely related to its antileukocyte adherence property. They evaluated the efficacy of sulfated polysaccharides (unfractionated heparin, low-molecular-weight heparin, heparan sulfate, chondroitin sulfate C, and dextran sulfate) on leukocyte accumulation, infarction size, and neurological outcome after transient focal cerebral ischemia in rats subjected to 1 hour of ischemia and 48 hours of reperfusion. Forty-nine animals were included in the study. The animals receiving unfractionated heparin or dextran sulfate showed a significant reduction in leukocyte accumulation, infarct size, and neurological dysfunction 48 hours after reperfusion (p < 0.05) when compared to untreated animals. The animals receiving unfractionated heparin also showed significantly better results than the animals receiving an equivalent anticoagulant dose of low-molecular-weight heparin. These data indicate that heparin's antileukocyte property plays a more important role than its anticoagulant ability in neuronal protection. The relative potency of the sulfated polysaccharides tested in leukocyte depletion was closely related to their degree of sulfation. Thus, in addition to demonstrating the potential efficacy of heparin as a therapeutic agent for ischemia and reperfusion injury by the prevention of leukocyte accumulation, the results also serve as a basis for studying important cellular and molecular events that contribute to tissue damage.

Animals↗
PubMed1995

Inhibition of glycogenin-catalyzed glucosyl and xylosyl transfer by cytidine 5'-diphosphate and related compounds.

The self-glucosylation of beef kidney glycogenin was inhibited by the following pyrimidine nucleotides and nucleotide sugars, listed in order of decreasing effectiveness: CDP-glucose, CDP, UDP-xylose, UDP-N-acetylglucosamine, UDP-galactose, UDP, CTP, CDP-choline, UDP-glucuronic acid, beta-S-UDP-glucose, and CMP. In contrast, the purine nucleotide sugars, ADP-glucose and GDP-glucose, were essentially ineffective, as was the pyrimidine nucleoside, cytidine. UDP-Xylose may be utilized by glycogenin as an alternative sugar donor instead of UDP-glucose (Rodén, L., Ananth, S., Campbell, P., Manzella, S., and Meezan, E. (1994) J. Biol. Chem. 269, 11509-11513) and therefore presumably inhibited the glucosyl transfer reaction by being a competitive substrate. Like glucosyl transfer, xylosyl incorporation into glycogenin was also inhibited effectively by CDP. On the other hand, UDP-xylose:proteoglycan core protein xylosyltransferase (EC 2.4.2.26) was not affected by CDP, nor was it inhibited by UDP-glucose. Addition of CDP or UDP-glucose to reaction mixtures containing both enzymes therefore made it possible to assay xylosyltransferase EC 2.4.2.26 reliably without the extensive product characterization that is otherwise necessary. The CDP effect on glycogenin further allowed the development of an improved procedure for the purification of this enzyme, in which specific elution of an affinity matrix (UDP-glucuronic acid-agarose) was carried out with CDP as the eluant.

Animals↗
PubMed1995

Expression of type-X collagen in osteoarthritis.

The present study was undertaken to examine how osteoarthritis affects the expression of type-X collagen, a hypertrophic chondrocyte-specific collagen in articular cartilage. A well characterized sheep polyclonal antiserum, as well as three mouse monoclonal antibodies against canine type-X collagen, was used to immunolocalize type-X collagen in human and canine joints. Its expression in osteoarthritic cartilage was altered in several locations. In the canine osteoarthritic joints, type-X collagen increased in and just above the zone of calcified cartilage and was present diffusely throughout the calcified matrix. In both the human and canine cartilage, type-X collagen was localized around cell clones in the transitional zone of cartilage. This is surprising, since that region of the cartilage does not calcify and one of the proposed roles of type-X collagen is in mineralization. Thus, the osteoarthritic process may damage the matrix in the superficial layer and induce changes leading to the expression of the hypertrophic chondrocyte phenotype.

Animals↗
PubMed1995

Identification of heterogeneous cell populations in normal human intervertebral disc.

There is clear evidence that tissues related to the intervertebral disc, such as articular cartilage, contain several phenotypically different chondrocytic cell populations. Histological data for the disc suggest the same may be true for the annulus fibrosus and nucleus pulposus, but this has not been shown directly. For the first time, cells from adult human nondegenerative nucleus pulposus and annulus fibrosus were recovered after enzymatic digestion and maintained in an alginate bead culture system for up to 6 wk. The cells remained viable and produced matrix, but did not divide. Cultured cells were stained simultaneously for the presence of chondroitin sulphate and keratan sulphate, or types I and II collagen. The majority of the cells from both the annulus fibrosus and the nucleus pulposus produced both keratan sulphate and chondroitin sulphate (> 60%), a few only detectable levels of one or the other, but a significant population produced neither. This is an indication of a population of cells with a nonchondrocytic phenotype. In nondegenerative discs, the majority of the annulus fibrosus cells produced both types I and II collagen but the majority of nucleus pulposus cells produced only type II collagen. These observations are consistent with the presence of at least 2 phenotypically stable populations of cells in the adult human intervertebral disc and with the view that the phenotype of the major population of the annulus is different from that of the nucleus.

Adult↗
PubMed1993

Immunolocalization of selected cytokines and proteases in canine articular cartilage after transarticular loading.

Cytokines and proteases are thought to play a role in the destruction of cartilage and the development of osteoarthritis. The purpose of this study was to document chronological involvement of interleukin-1 beta (IL-1 beta), tumor necrosis factor-alpha (TNF-alpha), stromelysin (MMP-3), fibronectin, and alteration in the chondroitin sulphate sulfation pattern. Canine patellae underwent a closed-joint impact to induce the development of osteoarthritis. The animals were killed at 2, 12, 24, and 52 weeks. The patellar damage included cracks in the superficial zone of cartilage and the zone of the calcified cartilage-bone interface, vertical step-off fractures in the zone of calcified cartilage, and loss of proteoglycan around the cracks in the deep and superficial zones of cartilage. With avidin-biotin immunohistochemistry, these specimens were stained with antibodies to IL-1 beta, TNF-alpha, MMP-3, fibronectin, and altered proteoglycan sulfate with the monoclonal antibody 3-B-3. Three of the four specimens obtained at 2 weeks demonstrated a strong cellular and weak matrix staining pattern for IL-1 beta, TNF-alpha, MMP-3, and fibronectin around the cracks in the superficial and transitional zones of cartilage. No consistent staining pattern was noted in the cracks in the deep zone. None of the specimens obtained at 12, 24, or 52 weeks stained for these antibodies. No staining for the abnormal sulfation with the 3-B-3 antibody was evident in any specimen. The specimens obtained at 52 weeks showed healing of the step-off fractures and a filling-in of the proteoglycan loss. This model probably reflects the short-term cartilaginous changes in the patella after trauma; thus, only transient elevations in the cytokines and proteases were evident.

Animals↗
PubMed1993

Role of acute trauma in development of osteoarthritis.

Two canine acute transarticular loading models have been developed to study the role of acute traumatic cartilage damage in the development of osteoarthritis. One model involves damage to a closed joint and has the advantage of maintaining normal joint biology. The second model involves impaction of an open joint with direct visualization of the cartilage and has the advantages of being able to change the placement, intensity, and geometry of the impaction. Comparison of preliminary histochemical data at 2 weeks and 3 months for the open joint model with previously published data on the closed joint model is consistent with the two models having similar initial features that include surface cracks and step fractures of the zone of calcified cartilage. The early changes include loss of proteoglycan, expression of the pro-inflammatory markers such as TNF-alpha and IL-1 beta, and the metalloprotease stromelysin. By 3 months, cloning is present. The models will be useful in evaluating two hypotheses: one, that there is a threshold of damage that must be exceeded before the lesions became progressive and two, the cracks in the zone of calcified cartilage contribute to progression of osteoarthritis by acting as sites of endochondral ossification and thereby decreasing cartilage thickness.

Animals↗
PubMed1993

Cell surface CD44-related chondroitin sulfate proteoglycan is required for transforming growth factor-beta-stimulated mouse melanoma cell motility and invasive behavior on type I collagen.

Tumor cell metastasis involves a complex series of events, including the adhesion, migration and invasive behavior of tumor cells on components of the extracellular matrix. Multiple cell surface receptors mediate interactions with the surrounding extracellular matrix and thereby influence cell adhesion, motility and invasion. We have previously described a cell surface CD44-related chondroitin sulfate proteoglycan on highly metastatic melanoma cells. CD44-chondroitin sulfate proteoglycan was shown to be important in melanoma cell motility and invasive behavior on type I collagen matrices. In our current studies, the role of cell surface CD44-chondroitin sulfate proteoglycan in collagen-mediated mouse melanoma cell migration and invasive behavior is further evaluated using transforming growth factor-beta 1. We report that transforming growth factor-beta 1 stimulates the migratory and invasive behavior of mouse melanoma cells on type I collagen. Transforming growth factor-beta 1 stimulated cell surface CD44-chondroitin sulfate proteoglycan synthesis in mouse melanoma cells, specifically through an upregulation of chondroitin sulfate production, while the expression of CD44-chondroitin sulfate proteoglycan core protein was not affected. Furthermore, transforming growth factor-beta 1-mediated enhancement of cell polarity, migration and invasive behavior on type I collagen gels was markedly inhibited in the presence of beta-D-xyloside, an agent that blocks chondroitin sulfate addition to the core protein. Collectively, our findings indicate that mouse melanoma cell surface CD44-chondroitin sulfate proteoglycan is required for transforming growth factor-beta 1-enhanced cell motility and invasion, and that CD44-chondroitin sulfate proteoglycan may play a role in forming and/or maintaining a dominant leading lamella, which is required for efficient locomotion.

Aggrecans↗
PubMed1993

Scanning electron-microscopic and magnetic resonance-imaging studies of injuries to the patellofemoral joint after acute transarticular loading.

To examine the effects of transarticular loading on articular cartilage and subchondral bone, we used a canine model that we had developed previously, in which a standardized load of approximately 2000 newtons is delivered across the patellofemoral joint. The purpose of the study was to define and describe the initial changes, as seen on histopathological and magnetic resonance-imaging studies, that occur in the early stages after injury to the joint by transarticular loading. Scanning electron microscopy was used to define the extent and characteristics of the fractures produced in the subchondral bone of four patellae that were examined on the day of loading. We found multiple, extensive fractures through the zone of calcified cartilage and the subchondral bone, frequently with step-off displacement, and with little or no change in the gross appearance of the articular cartilage. Specimens from four patellae were examined histologically two weeks after loading, and the observed changes were correlated with those that had been demonstrated by scanning electron microscopy. Fractures through the zone of calcified cartilage and the subchondral bone, with step-off displacement, were prominent. Clefts were present in the surface of the articular cartilage and, in some areas, there was a focal loss of proteoglycan from the extracellular matrix, as indicated by the complete absence of staining with safranin O. Six dogs were examined one year after loading. There was healing of the subchondral fractures and restoration of proteoglycan in the extracellular matrix. However, superficial clefts and fissures were still present in the articular cartilage. Sequential magnetic resonance-imaging studies were also carried out on these six dogs, at two, eight, sixteen, thirty-six, and fifty-two weeks after loading. Two weeks after loading, all knees had soft-tissue swelling, effusion, and a decreased marrow signal in the medullary cavity of the patella. The decreased marrow signal and effusion were still present eight weeks after the impact, and then the findings gradually returned to normal. One year after loading, it was found that the histopathological changes had not been progressive; in fact, they had been ameliorated and, to some extent, reversed by repair processes. The early, severe magnetic resonance-imaging changes had also been reversed, so that this study demonstrated normal findings by one year after loading.

Animals↗
PubMed1993

Biochemistry of the intervertebral disc.

In comparison to other tissues, understanding the disc biochemistry is only in the very early stage. The few facts that are known would point to strategies for interventions to alter disc biology and maintain disc biomechanics.

Biochemical Phenomena↗
PubMed1993

Histochemical and immunohistochemical characterization of cells constituting the giant cell tumor of bone.

Enzymatic activity and cell membrane proteins were characterized in cells from five giant cell tumors of bone (GCTs). Naphthyl alpha esterase (NAE) and acid phosphatase (AP) activity was noted within both the mononuclear and multinucleated cells of each tumor. In each tumor, all mononucleated cell populations displayed tartrate-sensitive AP activity, whereas the multinucleated cell populations demonstrated variable expression of tartrate-sensitive and tartrate-resistant AP activity. Analysis of cell membrane proteins included attempts at immunodetection of mannose receptor, OKM-1 antigen (OKM-1a), colony-stimulating factor-1 receptor (CSF-1r), and platelet-derived growth factor receptor (PDGFr). None of these membrane antigens were elicited on multinucleated cells. In contrast, the mannose receptor, OKM-1a, and PDGFr all were detected on the mononucleated cells within each tumor. These data demonstrate that a population of mononucleated, not multinucleated cells, expresses features unique to mature mononuclear phagocytes and establishes the presence of a membrane receptor, PDGFr, associated with mitogenesis of mesenchymal cells.

Acid Phosphatase↗
PubMed1992

Initial characterization of the metabolism of intervertebral disc cells encapsulated in microspheres.

Adult, canine intervertebral disc cells were isolated with a sequential digestion of pronase and bacterial collagenase. The nonchondrodystrophoid nucleus pulposus exhibits two populations of cells: large notochordal cells and smaller chondrocyte-like cells. The cells from the transition zone and anulus fibrosus are uniform in size, ranging from 17 to 21 microns. The isolated cells were encapsulated in alginate beads and cultured in Ham's F-12 medium containing 5% heat-inactivated fetal bovine serum. Alginate bead formation requires calcium ions and can be reversed with a suitable chelator, thus releasing viable cells. We observed that 58% of the newly synthesized proteoglycans formed large-molecular-weight aggregates with hyaluronic acid. The proteoglycans contained low amounts of keratan sulfate (KS) (less than 5% of the total glycosaminoglycans synthesized). The chondroitin sulfates (CS) consisted of 51-67% as 6-O-sulfate and 29-39% as 4-O-sulfate, with the remainder (4-10%) present as 4,6-sulfate for all three zones of the disc. The majority of cells synthesized significant amounts of matrix as evidenced by Alcian Blue staining. By immunohistochemical analysis, the matrix contained chondroitin 6-sulfate as demonstrated by monoclonal antibodies to the unsaturated disaccharides remaining on the proteoglycan core after chondroitinase ABC digestion. Keratan sulfate was also present in the majority of the matrices around cells. These results emphasize the similarity of the newly synthesized proteoglycans secreted by cells grown in alginate beads to those synthesized by the neonate disc. These experiments also demonstrate the usefulness of this method as a microculture technique for disc cells.

Animals↗
PubMed1992

Subchondral damage after acute transarticular loading: an in vitro model of joint injury.

Intact canine metacarpophalangeal and metatarsophalangeal joints were subjected to a variety of loads in vitro. Intraarticular fracture occurred in 19 joints loaded to an average force of 2.4 +/- 0.4 kN with a corresponding loading rate of 88 +/- 23 kN/s. The remaining 29 joints were without gross evidence of fracture with an average load and loading rate of 1.7 +/- 0.9 kN and 64 +/- 32 kN/s, respectively. In the fractured specimens, damage to the zone of calcified cartilage and subchondral bone was much more extensive than was initially evident by gross inspection when assessed by scanning electron microscopy. Cracks with associated step-off displacement at the zone of calcified cartilage were found distant to the gross fractures. These findings were confirmed histologically. In addition, cracks localized to the zone of calcified cartilage were commonly identified histologically in specimens loaded in the range of 1.9-2.8 kN, but were not grossly fractured. The contact area determined with pressure-sensitive film increased with increasing load up to the point of fracture. The average pressure generated at the articular cartilage surface at the time of fracture in this model is > or = 40 MPa, and the fracture occurred at the contact site. Our findings suggest that failure in acute transarticular loading begins in the zone of calcified cartilage and subsequently involves the subchondral bone and overlying cartilage. This type of injury may contribute to the development of osteoarthritis after intraarticular fracture, or at high loads that do not result in gross fracture.

Animals↗
PubMed1992

A cell surface chondroitin sulfate proteoglycan, immunologically related to CD44, is involved in type I collagen-mediated melanoma cell motility and invasion.

The metastatic spread of tumor cells occurs through a complex series of events, one of which involves the adhesion of tumor cells to extracellular matrix (ECM) components. Multiple interactions between cell surface receptors of an adherent tumor cell and the surrounding ECM contribute to cell motility and invasion. The current studies evaluate the role of a cell surface chondroitin sulfate proteoglycan (CSPG) in the adhesion, motility, and invasive behavior of a highly metastatic mouse melanoma cell line (K1735 M4) on type I collagen matrices. By blocking mouse melanoma cell production of CSPG with p-nitrophenyl beta-D-xylopyranoside (beta-D-xyloside), a compound that uncouples chondroitin sulfate from CSPG core protein synthesis, we observed a corresponding decrease in melanoma cell motility on type I collagen and invasive behavior into type I collagen gels. Melanoma cell motility on type I collagen could also be inhibited by removing cell surface chondroitin sulfate with chondroitinase. In contrast, type I collagen-mediated melanoma cell adhesion and spreading were not affected by either beta-D-xyloside or chondroitinase treatments. These results suggest that mouse melanoma CSPG is not a primary cell adhesion receptor, but may play a role in melanoma cell motility and invasion at the level of cellular translocation. Furthermore, purified mouse melanoma cell surface CSPG was shown, by affinity chromatography and in solid phase binding assays, to bind to type I collagen and this interaction was shown to be mediated, at least in part, by chondroitin sulfate. Additionally we have determined that mouse melanoma CSPG is composed of a 110-kD core protein that is recognized by anti-CD44 antibodies on Western blots. Collectively, our data suggests that interactions between a cell surface CD44-related CSPG and type I collagen in the ECM may play an important role in mouse melanoma cell motility and invasion, and that the chondroitin sulfate portion of the proteoglycan seems to be a critical component in mediating this effect.

Animals↗
PubMed1992

Cell surface phosphatidylinositol-anchored heparan sulfate proteoglycan initiates mouse melanoma cell adhesion to a fibronectin-derived, heparin-binding synthetic peptide.

Cell surface heparan sulfate proteoglycan (HSPG) from metastatic mouse melanoma cells initiates cell adhesion to the synthetic peptide FN-C/H II, a heparin-binding peptide from the 33-kD A chain-derived fragment of fibronectin. Mouse melanoma cell adhesion to FN-C/H II was sensitive to soluble heparin and pretreatment of mouse melanoma cells with heparitinase. In contrast, cell adhesion to the fibronectin synthetic peptide CS1 is mediated through an alpha 4 beta 1 integrin and was resistant to heparin or heparitinase treatment. Mouse melanoma cell HSPG was metabolically labeled with [35S]sulfate and extracted with detergent. After HPLC-DEAE purification, 35S-HSPG eluted from a dissociative CL-4B column with a Kav approximately 0.45, while 35S-heparan sulfate (HS) chains eluted with a Kav approximately 0.62. The HSPG contained a major 63-kD core protein after heparitinase digestion. Polyclonal antibodies generated against HSPG purified from mouse melanoma cells grown in vivo also identified a 63-kD core protein. This HSPG is an integral plasma membrane component by virtue of its binding to Octyl Sepharose affinity columns and that anti-HSPG antibody staining exhibited a cell surface localization. The HSPG is anchored to the cell surface through phosphatidylinositol (PI) linkages, as evidenced in part by the ability of PI-specific phospholipase C to eliminate binding of the detergent-extracted HSPG to Octyl Sepharose. Furthermore, the mouse melanoma HSPG core protein could be metabolically labeled with 3H-ethanolamine. The involvement of mouse melanoma cell surface HSPG in cell adhesion to fibronectin was also demonstrated by the ability of anti-HSPG antibodies and anti-HSPG IgG Fab monomers to inhibit mouse melanoma cell adhesion to FN-C/H II. 35S-HSPG and 35S-HS bind to FN-C/H II affinity columns and require 0.25 M NaCl for elution. However, heparitinase-treated 125I-labeled HSPG failed to bind FN-C/H II, suggesting that HS, and not HSPG core protein, binds FN-C/H II. These data support the hypothesis that a phosphatidylinositol-anchored HSPG on mouse melanoma cells (MPIHP-63) initiates recognition to FN-C/H II, and implicate PI-associated signal transduction pathways in mediating melanoma cell adhesion to this defined ligand.

Amino Acid Sequence↗