摘要:

AbstractAccurate estimation of cellular viability is important both in research and in aspects of orthopaedic clinical practice. We have been interested in the potential for flow cytometric application of fluorescein diacetate (FDA) in evaluating chondrocyte survival following cryopreservation of osteochondral allografts as well as in the assessment of sarcoma necrosis following preoperative chemotherapy. In order to evaluate the suitability of this method for cell viability assays, this study compared FDA with more traditional methodology (trypan blue, clonigenic assay, metabolic activity analysis, measurement of DNA synthesis, and histological assessment of necrosis). Both chondrocytes and sarcoma cells were exposed to various experimental injuries prior to viability analysis. Although it is evident from these experiments that FDA accurately reflects cell survival after physical injury, it underestimates the effect of chemotherapy on cell reproductive potential in vitro. However, FDA is highly correlated with histological assessment of tumor viability after chemotherapy in vivo. It is apparent that the methodology chosen for determination of viability should be appropriate for the type of experimental injury and should analyze the cell function (i.e., metabolic activity or reproductive capacity) that is appropriate for the experimental model.

ISSN:0736-0266    

DOI:10.1002/jor.1100060402

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

年代:1988

数据来源: WILEY

摘要:

AbstractThe Hulth instability model was performed on 25 rabbit knee joints. Electron‐microscopic, light‐microscopic, and histomorphometric data demonstrated consistent chondrocyte alterations and cartilage destruction. The comparison between operated, sham, and control knees shows that surgical intervention without surgically induced instability is followed by changes in the synovial membrane and cartilage. The cartilage destruction is preceded by a synovial reaction, suggesting that the inflammatory response has an important role in the onset of cartilage damage in this model. The damage was more severe in the experimental knees, suggesting that mechanical instability is also a factor in cartilge destruct

ISSN:0736-0266    

DOI:10.1002/jor.1100060403

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

年代:1988

数据来源: WILEY

摘要:

AbstractThis investigation illustrates the morphological changes that take place following eccentric exercise and correlates those changes with intramuscular pressure readings. Eight healthy male subjects were asked to exercise their right lower leg anterior compartment eccentrically and their left concentrically. Four hundred submaximal contractions were performed in each exercise regimen over a 20‐min period against a load corresponding to 15% of the individual's maximal dorsiflexion torque. Tissue fluid pressures were measured by the slit catheter technique before, during, and after exercise and 48 h later. Needle biopsies of both anterior tibialis muscles were also taken 48 h after completion of the exercise regimens. Overall morphology of the specimens revealed a greater cross‐sectional fiber area (both type 1 and type 2) in the eccentrically exercised muscle as compared with the concentrically exercised muscle. Scant evidence of infiammation (only 1 of 8 of the “eccentric” muscle samples) and no fiber necrosis was observed. Fiber type proportions were equal on both sides and type 1 fiber biased (70%). Extremely large type 2 fibers were found in 4 of 8 subjects from the eccentric specimens. This incidence correlated significantly with the length of the time to return to resting pressure after eccentric exercise (r= 0.93, p<0.001). The percentage of water content was significantly higher in the eccentrically exercised muscle. Based on these findings, we conclude that muscle fiber swelling is a predominant feature following eccentric exercise and is directly associated with delayed muscle s

ISSN:0736-0266    

DOI:10.1002/jor.1100060404

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

年代:1988

数据来源: WILEY

摘要:

AbstractWe measured patellofemoral contact areas and pressures using pressure sensitive film in ten human cadaver knees exhibiting degenerative lesions of patellar cartilage. We studied a flexion range from 20° to 90° and compared contact pressures before and after capsular reconstructive procedures. With an intact, normal capsule. localized lesions of grade I–II exhibited a 50% reduction in pressure (from 3.4 ± 0.7 MPa to 1.6 ± 0.9 MPa) directly over the lesion. Grade III–IV lesions exhibited a loss of contact pressure greater than 90%. This reduction in pressure appears to result from a loss of stiffness in the low grade cartilage lesions and from a loss of cartilage thickness in higher grade lesions. Highly localized peak pressures were also observed on the normal cartilage bordering the lesions. Capsular reconstructive procedures (medial plication, lateral release, and bilateral release) did not result in consistent pressure reductions or in the creation of more uniform pressure distribution. In particular, lateral capsular release, a popular surgical procedure, resulted in no change in three knees and four different pressure patterns in the other seve

ISSN:0736-0266    

DOI:10.1002/jor.1100060405

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

年代:1988

数据来源: WILEY

摘要:

AbstractWe performed a study to determine pressure distribution properties of the normal radio‐carpal joint. A system was developed for measurement of the contact pressure within the wrist joint surfaces. The transducer was based on Fuji pressure‐sensitive paper, which was inserted into the joint space through a dorsal capsular incision. The hand was then positioned using a jig that permitted free axial loading of the joint. Each of five specimens was tested in 36 positions combining flexion/extension with radio/ulnar deviation and supination/pronation. The transducers were analyzed for contact area, scapholunate contact area ratio, pressure, and centroid locations using a microcomputer‐based video‐imaging system. The scaphoid and lunate contact areas on the radius and traingular fibrocartilage were separate and distinct in all wrist positions. Together these contact areas accounted for a relatively small fraction of the total joint surface area (average contact area/total joint area = 0.206, SD = 0.0495). For an applied 103 Newton compressive load, the high pressure averaged 3.17 MPa (SD = 0.83 MPa). Overall, the scaphoid contact area was 1.47 times that of the lunate, although variations occurred with position, as in flexion, in which the scaphoid/lunate area ratio was 0.83. The highpressure centroids of both scaphoid and lunate contact areas shifted palmarly from 20° of flexion to 20° of extension and then dorsally with further extension. The scaphoid‐lunate intercentroid distance averaged 14.91 mm with a range

ISSN:0736-0266    

DOI:10.1002/jor.1100060406

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

年代:1988

数据来源: WILEY

摘要:

AbstractThe effect of ascorbate on the proteoglycans synthesized by rabbit articular chondrocytes was studied in first‐ and third‐passage cultures for 12 and 26 days total duration, respectively.L‐Ascorbate (0.2 mM) was added daily to half of the flasks after attachment of the cells. The cultures were labeled with Na2[35S]O4or [14C]‐glucosamine and [3H]‐proline. Proteoglycans were isolated from the media and pericellular matrices by dissociative extraction and associative density gradient centrifugation. There was a large decline in the amount of proteoglycan synthesized between early and late cultures. Ascorbate increased the DNA content, amount of radiosulfate incorporated into glycosaminoglycans per microgram of DNA, and the proportion of labeled proteoglycan in the percellular fraction of both short‐ and long‐term cultures. The proteoglycans of the media and matrices of all cultures, with and without ascorbate, eluted as aggregates under associative column chromatographic conditons. The proteoglycans of 26‐day cultures exhibited a higher degree of polydispersity in size than those of the short‐term culture and contained small amount of keratan (2–5%) and dermatan sulfate (4–8%) as assessed by keratanase and chondroitinase digestions, respectively. The effect of ascorbate, therefore, was to increase the amount of proteoglycan formed and to direct it into matrix deposition rather than

ISSN:0736-0266    

DOI:10.1002/jor.1100060407

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

年代:1988

数据来源: WILEY

摘要:

AbstractAddition of CoCl2solutions to the culture media of confluent monolayers of lapine or human synoviocytes stimulated their production of the neutral proteinases collagenase, gelatinase, and caseinase. With lapine cells, maximum stimulation occurred at 10−7MCoCl2, while human cells required 10−4–10−5MCoCl2to achieve a maximum stimulation. Production of prostaglandin E2by lapine cells was enhanced some 30–40% by concentrations of CoCl2that maximally stimulated synthesis of the neutral proteinases, whereas all concentrations of CoCl2slightly depressed the productio of prostaglandin E2by human celis. Lapine synovial cells that had been stimulated by CoCl2also produced a substance, or substances, that provoked the synthesis of collagenase, gelatinase, caseinase, and prostaglandin E2by monolayers of articular chondrocytes. Chondrocytes themselves, however, resisted activation by CoCl2. These findings may be relevant to the aseptic loosening of joint p

ISSN:0736-0266    

DOI:10.1002/jor.1100060408

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

年代:1988

数据来源: WILEY

摘要:

AbstractThe optical bone chamber technique that includes intravital microscopy is described and is then applied to measuring primary wound healing neoostogenesis in rabbit tibia cortical bone during the period when fibrovascular tissue is being replaced by regenerating osteovascular tissue. The small population of rabbits sampled allowed only tentative conclusions. The quantitative measurements, a direct form of histomorphometry, are applied to determine the consistency of observations, with the hypothesis that healing into the bone chamber slit‐gap follows the pattern of primary bone regeneration established as “characteristic” by other studies. The results supported the hypothesis and showed that bony ingrowth started during the third postoperative‐week (W3) with a maximum linear growth rate of 85.5 μm/day for a bone front. Evidence for remodeling by W6 was also obtained. While the bone chamber environment for tissue ingrowth is artificial, it can generate quantitative data that may provide a statistically valid basis for modeling pathophysiologic processes associated with bone wound

ISSN:0736-0266    

DOI:10.1002/jor.1100060409

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

年代:1988

数据来源: WILEY

摘要:

AbstractCurrently, three criteria are accepted as indications for prophylactic internal fixation of metastatic disease in long bone, including lesions (a) destroying 50% or more of the cortex; (b) 2.5 cm or greater in diameter; or (c) with pain unrelieved by radiation therapy. Using an oblong defect configuration in which one half of the cross‐sectional area was destroyed, canine femora were torsion‐tested at high speed to determine (a) the actual strength reduction incurred by a lesion destroying 50% of the cortical circumference, and (b) the effects and benefits of internal fixation using polymethylmethacrylate and/or a six‐hole compression plate on such a defect. The femurs with a 50% circumferential cortical defect demonstrated only 12.7 ± 3.8% of intact strength. Defects treated with a combination of plating (all screws bicortical) and polymethylmethacrylate (torque to failure 4.39 ± 0.90 times greater than the defect alone or TE/TD= 4.39 ± 0.90) were statistically stronger than defects treated with polymethylmethacrylate alone (TE/TD= 2.48 ± 0.66; p<0.025) or by plating alone (TE/TD= 2.61 ± 0.91; p<0.025), but torque‐to‐failure was only increased to approximately 56% of an intact bone. Plated intact bones (TE/TD= 5.33 ± 0.41) were significantly weaker than intact bones (TE/TD= 8.50 ± 2.52; p<0.001). Our results substantiate the need for using polymethylmethacrylate and internal fixation in combination when prophylactically fixing pathologic lesions of

ISSN:0736-0266    

DOI:10.1002/jor.1100060410

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

年代:1988

数据来源: WILEY

摘要:

AbstractThe load‐carrying capacity of the skeleton is achieved and maintained as the result of a continued functional stimulus to the cell populations responsible for bone remodeling. Although some bone cells have been assumed to be influenced by the load‐induced changes in strain throughout the matrix, no evidence is available to indicate which cells are susceptible to such strain change or how such transient events provide a sustained influence on cell behaviour. In the present study, we showed that a short period of dynamic loading in vivo affects the orientation of proteoglycan within bone tissue. This reorientation declines only slowly, thus providing a persistent record of the tissue's recent strain history. Such a record has the ability not only to “capture” strain transients but also to “update” and “average” them. In this way, the bone cells could be presented with a sustained and coherent stimulus directly related to dynamic strain transients. These transients are the tissue's principal fu

ISSN:0736-0266    

DOI:10.1002/jor.1100060411

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

年代:1988

数据来源: WILEY