摘要:

AbstractTo determine the fate of transplanted cryopreserved articular cartilage, an animal model employing the proximal humerus in the rabbit has been developed. Previous studies have been hindered by problems of postoperative joint instability, secondary injury due to immobilization, and paucity of cartilage for analysis. This experiment demonstrates the survival and function of transplanted cartilage by quantitative assessment of metabolic and biochemical parameters. Forty‐five New Zealand white rabbits underwent transplantation of the right proximal humerus. In 29 animals, the proximal half of the humerus was resected and replaced by a cryopreserved osteoarticular allograft. Autograft procedures were carried out in the remaining animals. Following sacrifice at 3, 6, 9, and 12 months postoperatively, articular cartilage was analyzed for gross appearance, collagen synthesis, proteoglycan synthesis, and water, hydroxyproline, hexosamine, and hexuronic acid contents. The results indicate that the cryopreserved osteoarticular allografts retained their metabolic and biochemical intergrity and behaved as viable and biologically functional units 1 year postoperativel

ISSN:0736-0266    

DOI:10.1002/jor.1100100502

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractCultured bovine articular cartilage was subjected to 50 ms, 0.5–1.0 MPa compressions repeated at intervals of 2–60 s for 1.5 h and simultaneously labeled with35SO4. The compression was delivered with a 4‐mm‐diameter nonporous loading head on an 8‐mm‐diameter cartilage explant. This method created directly compressed (central) and uncompressed (border) areas within the tissue. Analysis of the whole explant under a 0.5 MPa load showed significantly increased35SO4incorporation by compression repeated at 2‐ and 4‐s but not at 20‐ and 60‐s intervals. When the incorporation was studied separately in the border and central areas, a statistically significant stimulation was noticed in the central area with a 4‐s cycle, while the border area was stimulated with a 2‐s cycle. Autoradiography of the central area showed that the stimulation with 0.5 MPa and a 4‐s cycle occurred through the whole depth of the cartilage, while raising the pressure to 1 MPa or the frequency to 2 s reduced the stimulation, particularly in the superficial cartilage. In the border area the stimulation with 0.5 MPa and a 2‐s cycle was noted in the superficial zone only. The stimulation of proteoglycan synthesis is thus limited to certain loading frequencies and pressures and occurs in specific areas under and around the loaded site. Its rapid appearance suggests enhanced glycosylation or sulfation of core proteins or enhanced speed of p

ISSN:0736-0266    

DOI:10.1002/jor.1100100503

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractHuman cartilage link protein exists as three native components, while equine, bovine, and porcine cartilage link protein exist as two and Swarm rat chondrosarcoma link protein exists as only one component. These nonhuman link protein components represent intact protein structures, and there is little evidence for proteolytically modified forms in nonhuman tissues. In human cartilage, the proteolytic production of modified link proteins increases with age, whereas high amounts of such products were not seen in the nonhuman tissues. However, the small amounts of link protein fragments that were observed in the nonhuman cartilages were of a similar size to their human counterparts. On digestion of human proteoglycan aggregate with stromelysin, rapid modification of the link protein components occurred, whereas the aggregates from nonhuman cartilages showed incomplete cleavage of their link protein components. The relative resistance of nonhuman link protein to stromelysin may in part be due to a unique amino acid substitution present near the enzymic cleave site.

ISSN:0736-0266    

DOI:10.1002/jor.1100100504

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractThe dermatan sulfate proteoglycans decorin and biglycan were extracted from pooled adult human menisci with 4Mguanidinium chloride and purified by successive cesium chloride density gradient centrifugation, ion exchange chromatography, and gel filtration. A final yield of about 2 mg of dermatan sulfate proteoglycan per gram of wet tissue was obtained. The proteoglycan is predominantly decorin with some biglycan, and the dermatan sulfate chains contain about 70% of their uronic acid residues as iduronate and possess about three times as much 4‐sulfation as 6‐sulfation of their N‐acetylgalactosamine residues. On gel filtration under associative conditions, about half of the proteoglycan exhibits self‐association. This includes most of the biglycan but also a substantial proportion of decorin. The molecules that show self‐association appear to have longer dermatan sulfate chains, though there is no apparent difference in their overall composition. The predominance of decorin in the adult meniscus and its ability to interact both with itself and collagen fibrils is compatible with a role in maintaining tissue integrity and

ISSN:0736-0266    

DOI:10.1002/jor.1100100505

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractThe basic fibroblast growth factor (bFGF) family of peptides influences a wide range of cellular actions. To better understand the possible role of bFGF in the growth plate, we have characterized the interaction of this growth factor with isolated bovine growth plate chondrocytes. Basic FGF interacts with two classes of binding sites on these cells. One is consistent with high‐affinity bFGF receptors and the other with low‐affinity heparin‐like binding sites on the chondrocyte surface. Radiolabeled bFGF binding studies revealed approximately 4 × 106binding sites per cell, with aKdof approximately 42 nM. Graded concentrations of heparin or NaCl competed with [125I]‐labeled bFGF in a dose‐dependent fashion, reducing [125I]‐labeled bFGF binding by 75 and 97%, respectively. The data suggest the presence of a high‐capacity, low‐affinity class of binding sites with the properties of a heparin‐like moiety. Affinity cross‐linking of [125I]‐labeled bFGF to chondrocytes labeled two principal species with apparent molecular masses of 135 and 160 kDa. Labeled bFGF was specifically displaced from both species by subnanomolar concentrations of unlabeled bFGF. These high‐affinity, low‐capacity binding sites are characteristic of classical bFGF receptors. Binding of [125I]‐labeled bFGF to these sites was also influenced by heparin, consistent with coregulation of binding to the two classes of binding sites. The data suggest that bFGF participates in the regulation of skeletal growth at the growth plate and that this regulation may involve bFGF interaction with at least two disti

ISSN:0736-0266    

DOI:10.1002/jor.1100100506

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractThe impact of naproxen treatment on juxta‐articular hemodynamics and bone metabolism in experimental juvenile arthritis was studied in the articular carrageenan injection model. Unilateral gonarthritis was induced for 12 weeks in eight dogs receiving naproxen (dosage, 2 mg/kg) and eight controls. Regional blood flow was assessed by the microsphere method, plasma volume by the distribution space of [125I]fibrinogen, and bone metabolism by the 2‐h uptake of [99mTc]diphosphonate ([99mTc]DPD). Synovial effusion was less prominent with naproxen treatment as judged by joint fluid volume and pressure. Naproxen reduced the arthritic capsular hyperemia, almost normalized a severe blood flow increase in patella and both juxta‐articular epiphyses, ameliorated an expansion of plasma volume in the patella and the distal femoral epiphysis, and normalized an increased [99mTc]DPD uptake in subchondral femoral bone and the tibial cortex. Significantly increased arteriovenous shunting in the arthritic extremity was unaffected by naproxen. The study suggests that long‐term cyclooxygenase inhibition offers protection against hemodynamic and metabolic changes in juxta‐articular bone secondary to synovial inf

ISSN:0736-0266    

DOI:10.1002/jor.1100100507

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractThis study evaluates the effect of crushing load on functional recovery of the sciatic nerve. Male Sprague‐Dawley rats were divided into five groups: sham operation, resected sciatic nerve, and 100 g (13 mm Hg/mm2), 500 g (50 mm Hg/mm2), and 15,000 g (1,000 mm Hg/mm2) of sciatic crush load (groups 1–5). In groups 3–5, a 5‐mm segment of sciatic nerve was crushed for 10 min using a specially designed crushing device. Motor functional recovery was assessed from hind‐limb walking tracks by calculating a sciatic functional index. There was no detectable functional deficit in the group receiving sham operations, while the resected sciatic nerve group exhibited complete dysfunction for the full duration of the experiment. All groups subjected to crush exhibited an initial deficit that gradually recovered to normal by day 14 (100‐g crush), day 39 (500‐g crush), and day 53 (15,000‐g crush). Histological changes were also related to the initial crushing load and the length of the recovery period. Results indicate that the crushing device described is able to administer an adjustable, defined crush injury to the rat sciatic nerve, and that the functional deficit resulting from such an injury can be easily monitored with a sciatic functional index. The rate of recovery of crushed nerves was directly related to the initial load. All crushed nerves recovered in this experiment, even after the application of a 15,000‐

ISSN:0736-0266    

DOI:10.1002/jor.1100100508

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractA 5 × 5‐mm anterolateral incision was made in the annulus fibrosus (AF) of lumbar discs of 16 sheep; four animals of similar age not operated on were used as controls. The experimental animals were sacrificed 2, 4, 6, 8, 12, and 18 months postoperatively (PO), and the incised and adjacent lumbar discs were collected. Discs were dissected into four zones: AF (zones 1 and 2) and nucleus pulposus (NP) (zones 3 and 4) corresponding to the half of the AF in which the cut was made and its opposite half, and the complementary halves of the NP. Each zone was analyzed for moisture, proteoglycan (PG), collagen, and noncollagenous protein (NCP) content. The PG extractability, aggregation, and hydrodynamic size were also examined. The NP of injured discs showed a significant loss of PGs and collagen 8 months PO, but NCP levels increased. In the incised discs, PG aggregation initially declined but recovered to within control values 6–8 months PO. The NP of discs adjacent to the incised disc also showed time‐dependent changes in matrix components that included loss of collagen and PG; however, the AF matrix remained essentially uneffected. Double immunodiffusion studies indicated that a sizeable proportion of the NCPs present in the injured discs (but not the adjacent lumbar discs) were derived from

ISSN:0736-0266    

DOI:10.1002/jor.1100100509

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractAdult, 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 μm. 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) (<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 microcult

ISSN:0736-0266    

DOI:10.1002/jor.1100100510

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractThis study investigated the cocontraction of eight trunk muscles during the application of asymmetric loads to the torso. External moments of 10, 20, 30, 40, and 50 Nm were applied to the torso via a harness system. The direction of the applied moment was varied by 30° increments to the subjects' right side between the sagittally symmetric orientations front and rear. Electromyographic (EMG) data from the left and right latissimus dorsi, erector spinae, external oblique, and rectus abdominus were collected from 10 subjects. The normalized EMG data were tested using multivariate and univariate analyses of variance procedures. These analyses showed significant interactions between the moment magnitude and the moment direction for seven of the eight muscles. Most of the interactions could be characterized as due to changes in muscle recruitment with changes in the direction of the external moment. Analysis of the relative activation levels, which were computed for each combination of moment magnitude and direction, indicated large changes in muscle recruitment due to asymmetry, but only small adjustments in the relative activation levels due to increased moment magnitude

ISSN:0736-0266    

DOI:10.1002/jor.1100100511

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY