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  • 1
    ISSN: 1437-160X
    Keywords: Key words Tenascin ; Total hip replacement ; Interface tissue ; Rheumatoid arthritis ; Osteoarthritis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The distribution of tenascin-X (Tn-X) was investigated in synovial samples from rheumatoid arthritis (RA), osteoarthritis (OA) and knee injuries, and in synovial membrane-like interface tissue (SMLIT) from aseptic loosening of total hip replacement (THR). An affinity purified rabbit antiserum against Tn-X was applied in avidin-biotin-peroxidase complex method. Double immunofluorescence labeling was used to assess the spatial relationship of Tn-X and Tn-C. All samples showed Tn-X immunoreactivity. Strong staining appeared in the lining and lining-like layers of RA and SMLIT samples, respectively. An intensive immunoreactivity was also found in pannus tissue in RA, and around multinucleate giant cells and polyethylene wear debris in SMLIT. Staining intensity/extent varied significantly in different samples in the following rank order: SMLIT, RA, OA, knee synovium membrane. Double labeling revealed two patterns of Tn-X/Tn-C distribution, reciprocal and co-localization. Our results suggest that Tn-X is an essential component of normal synovial membrane, and that inflammatory mediators may increase local Tn-X production. Tn-X distribution is not always reciprocal to that of Tn-C.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1437-160X
    Keywords: Key words Platelet-derived growth factor ; Total hip replacement ; Synovial-like membrane ; Aseptic loosening
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Aseptic loosening is the predominant cause of total hip implant failure. It has been assumed that a layer or membrane, containing macrophages, fibroblasts and vascular endothelial cells, of synovial-like tissue develops at the implant-to-bone interface almost invariably and, with time, somehow leads to loosening of the components from the surrounding bone. These cells produce a variety of cytokines and proteolytic enzymes which stimulate bone resorption. Platelet derived growth factor (PDGF) may be one of the cytokines which stimulate bone resorption and contribute to aseptic loosening in total hip replacement (THR). Synovial-like membrane from the implant or cement-to-bone interface (n=10) and pseudocapsule (n=10) were obtained from ten patients operated on for aseptic loosening of THR. As a control, nine samples of connective tissues were obtained from patients who had mandibular or maxillary fractures fixed with bone implant. The avidin-biotin-peroxidase complex (ABC) method with polyclonal rabbit anti-human IgG against the A-chain and B-chain of PDGF was used for staining. ABC-alkaline phosphatase-anti-alkaline-phosphatase double staining with monoclonal mouse anti-human fibroblast IgG1 and CD68 antibodies was used to ascertain the cellular origin of PDGF. Results of the PDGF staining were quantitated by a semi-automatic VIDAS image analysis system. The PDGF-A and PDGF-B chain containing cells were found in all periprosthetic tissues, in particular in macrophages with phagocytosed particulate debris, but to some extent also in fibroblasts and in endothelial cells. The numbers of PDGF-A and PDGF-B chain positive cells per mm2 in synovial-like interface membrane (1881±486 and 1877±214) and pseudocapsule (1786±236 and 1676±152) were higher (P〈0.01) around loose THR than in control tissue (821±112 and 467±150), respectively. The results of the present study suggest that PDGF is preferably expressed by macrophages, which to an increased extent produce it in the synovial-like interface membrane and pseudocapsular synovial-like membrane. Because of its role in bone resorption, it may well play a role in periprosthetic bone loss and aseptic loosening and deserves more detailed study as a mediator and potential target in the modulation or prevention of loosening of THR.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-1084
    Keywords: Key words: MRI ; DXA ; Osteoporosis ; Lumbar vertebrae ; Bone density
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. The aim of this study was to investigate whether MR imaging of trabecular bone structure using magnetic inhomogeneity measurements is related to the amount of bone mineral in human vertebrae. Weight, bone mineral content (BMCDXA), bone mineral per area (BMADXA) and bone mineral density (BMDCT) were determined in 12 defatted human lumbar vertebrae (L2–L4) by weighing, dual X-ray absorptiometry (DXA) and CT. Inhomogeneity caused by susceptibility differences between trabecular bone and surrounding water was studied with MR imaging at 1.5 T using the GESFIDE sequence. The pulse sequence determines the transverse relaxation rate R2* and its two components, the non-reversible transverse relaxation rate (R2) and the reversible transverse relaxation rate (R2'; i. e. relaxation rate due to magnetic susceptibility) in a single scan. Voxel size was 0.9 × 1.9 × 5.0 mm. Positive significant correlations between R2' and weight, BMCDXA, BMADXA and BMDCT were observed (r 〉 0.61 and p 〈 0.05 for all). Unexpectedly, R2 was also positively correlated with weight, BMCDXA and BMDCT (r 〉 0.66 and p 〈 0.05 for all), but not with BMADXA. Thus, R2' measurements are related to the amount of bone mineral, but they also provide information which is not obtainable from bone mineral measurements.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    European radiology 9 (1999), S. 643-647 
    ISSN: 1432-1084
    Keywords: Key words: MRI ; CT ; Lumbar vertebrae ; Osteoporosis ; Trabeculae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. The aim of the study was to assess the relative number of bone trabeculae in different orientations by using magnetic inhomogeneity measurements by MR imaging. Twelve defatted human vertebrae (L2–L4) were studied by MR imaging and CT. In the MR measurements the reversible transaxial decay rate, R2', was determined using the GESFIDE sequence. The relative contribution to R2' of bone trabeculae oriented along the x (R2'x), y (R2'y) and z (R2'y) axes was assessed, by rotation of the specimen in the magnetic field. The results were validated by CT measurements of trabecular structure at a resolution of 0.2 × 0.2 × 1 mm, using custom-made software. R2' ranged from 4.9 to 32 s–1. After separation, theoretical R2'x ranged from 2.3 to 10.7 s–1, R2'y ranged from 2.6 to 14.0 s–1 and R2'z ranged from 4.7 to 17.9 s–1. The number of bone trabeculae per millimeter identified in axial CT images ranged from 0.15 to 0.38 and from 0.039 to 0.22 per millimeter in sagittal images. The difference between axial and sagittal CT images was statistically significant and due to anisotropic voxels. The correlation between R2' and the number of bone trabeculae per millimeter was statistically significant (r = 0.83, p 〈 0.001 for x orientation; r = 0.63 for y orientation, and r = 0.59 for z orientation, p 〈 0.05 for both). The relative amount of bone trabeculae in different orientations can be assessed in vitro using R2' measurements.
    Type of Medium: Electronic Resource
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