ISSN:0736-0266    

DOI:10.1002/jor.1100160602

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

年代:1998

数据来源: WILEY

摘要:

AbstractAlthough the timely conveyance of information at national meetings like those of the Orthopaedic Research Society is critical to the dissemination of new scientific research, the ultimate goal of most researchers is to publish work in peer‐reviewed journals referenced in Medline. All of the abstracts that were presented at the podium at the 1991. 1992. and 1993 annual meetings of the Orthopaedic Research Society and printed in the appropriate yearly transactions were included in this study (n = 888, 296 per year). A detailed computerized Medline search of each author on the abstract and the appropriate keywords from the title was performed until a publication was found; otherwise, the abstract was excluded. The database was searched through June 30. 1997. A total of 463 (52%) of the abstracts were published by July 1, 1997. The percentages for each individual year were similar: 148 (50%) were published in 1991,162 (55%) in 1992, and 153 (52%) in 1993. Publication of the majority of these papers (93.1%, 431 of 463) occurred within 4 years of the respective meeting.The Journal of Orthopaedic Researchpublished the majority of these papers (17.5%), followed byThe Journal of Bone and Joint Surgery (American), theJournal of Biomechanics, Clinical Orthopaedics and Related Research, and Spine(each 5.2%). No significant differences in the rate of publication were observed between papers of 10 broad subject categories (p = 0.103). These results are similar to those from other basic science meetings and to the recently reported results for the annual meeting of the American Academy of Orthopaedic Surgeon

ISSN:0736-0266    

DOI:10.1002/jor.1100160603

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

年代:1998

数据来源: WILEY

摘要:

AbstractTo investigate the effect of 25‐OH‐vitamin D supplements (calcidiol) on fracture healing in the elderly, an experimental model with 15 18‐month‐old female Wistar rats was designed. An experimental fracture in the middle third of both femora of each rat was made. Then the rats were randomly assigned to two groups: one group was subcutaneously treated with 25‐OH‐vitamin D during all healing processes, and the other group (the control group) was not. After 5 weeks of healing, the animals were killed and both femora were extracted. Blood samples were collected before fracture and at death to determine the levels of 25‐OH‐vitamin D. All bones that were extracted were subjected to a torsion test to assess healing; a significantly greater maximum shear force before failure was supported in the treated group (p<0.01). Moreover, a positive correlation (p<0.01; r = 0.55) was found between blood levels of 25‐OH‐vitamin D at death and the mechanical strength of the callus. Thus, the administration of 25‐OH‐vitamin D after the experimental fracture significantly improved the mechanical strength of the fractured bone. If similar results are found in the human, then treatment with 25‐OH‐vitamin D after the occurrence of a fracture would be a good way to improve frac

ISSN:0736-0266    

DOI:10.1002/jor.1100160604

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

年代:1998

数据来源: WILEY

摘要:

AbstractThe effects of a single local injection of recombinant human fibroblast growth factor‐2 on the healing of segmental bone defects were evaluated in rabbits. One month after the external fixator originally designed for this experiment was installed in the tibia of the rabbit, a 3‐mm bone defect was created by an osteotomy in the middle of the tibia and 0, 50, 100, 200, or 400 μg of fibroblast growth factor‐2 in 100 μg of saline solution was injected into the defect. Injection of the growth factor increased the volume and mineral content of newly made bone at the defect in a dose‐dependent manner with significant effects at Concentrations of 100 μg or greater. These significant effects were observed at 5 weeks and later. One hundred micro‐grams of the growth factor increased the volume and mineral content of newly made bone by 95 and 36%, respectively, at 5 weeks. These results indicate that a single local injection of fibroblast growth factor‐2 stimulates the healing of segmental defects. We speculate that such an injection could be clinically useful for the healing of fractures even when the fracture gap i

ISSN:0736-0266    

DOI:10.1002/jor.1100160605

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

年代:1998

数据来源: WILEY

摘要:

AbstractIt has been hypothesized that bone resorption during tumor osteolysis is performed by osteoclasts. Data supporting this hypothesis have been provided from analysis of human biopsy specimens obtained from sites of tumor osteolysis, as well as from experimentation with in vivo animal models. Experiments in this report take this concept one step further by testing the hypothesis that osteoclasts are required for bone tumors to grow and destroy bone. To test this hypothesis, the influence of an osteolytic sarcoma tumor, NCTC clone 2472 (2472). on bone was studied in animals that are osteoclast deficient (microphthalmic, strain B6C3Fe‐a/a‐Mitfmi) but whose osteoclast deficiency can be reversed following bone marrow transplantation. Femora of these mice and unaffected wild‐type siblings were injected with 1052472 cells, and after 14 days the femora were analyzed by radiographic and histomorphometric analysis. Macroscopic tumor, tumor‐induced osteolysis, and increased osteoclast number were noted in femora of normal mice but not in femora of osteoclast‐deficient mice (p<0.001). Bone marrow transplantation converted osteoclast‐deficient mice to mice with femora that contained osteoclasts in 4 weeks. Femora of these mice were then injected with 1052472 tumor cells; after 14 days, in contrast to the findings in the original osteoclast‐deficient mice, macroscopic tumor was present, tumor‐induced osteolysis was noted on roentgenograms, and osteoclast number was increased when tumor‐bearing limbs were compared with sham‐injected limbs (p<0.001). These data prove the hypothesis that osteoclasts are required for 2472 tumor‐induced osteolysis, and they introduce the exciting possibility that osteoclasts are also required for t

ISSN:0736-0266    

DOI:10.1002/jor.1100160606

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

年代:1998

数据来源: WILEY

摘要:

AbstractProduction of nitric oxide by solid tumors may have important ramifications regarding tumor growth and potential metastasis. This study demonstrated that the chondrosarcoma of the Swarm rat has upregulated mRNA for inducible nitric oxide synthase and produces nitric oxide. These results were confirmed by (a) the, presence of a 4.4‐kb band of mRNA detected by Northern blot using a probe for inducible nitric oxide synthase, (b) a 133‐kDa band of prothein that was detected with either a polyclonal or monoclonal antibody to the inducible nitric oxide synthase of the murine macrophage. and (c) the detection of nitrites from the culture medium of freshly cultured, isolated chondrosarcoma cells. This study showed that the expression of inducible nitric oxide synthase and the production of nitric oxide by the tumor can be increased by stimulation with endotoxin lipopolysaccharide and can be inhibited by inducible nitric oxide synthase inhibitors (L‐N(g)‐monomethyl arginine and aminoguanidine). Immunostaining confirmed the presence of inducible nitric oxide synthase within the tumor cells and appeared to localize the enzyme to the cytoplasm of the cells. A human chondrosarcoma was also shown to have an upregulated inducible nitric oxide synthase by both the detection of mRNA for inducible nitric oxide synthase and the presence of nitrites from the culture medium of the tumor in organ culture. Because the chondrosarcoma of the Swarm rat is a well differentiated solid tumor that rarely metas‐tasizes, nitric oxide may be produced by the tumor to promote local growth by effects on vascul

ISSN:0736-0266    

DOI:10.1002/jor.1100160607

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

年代:1998

数据来源: WILEY

摘要:

AbstractThe posterolateral structures of the knee consist of a complex anatomical architecture that includes several components with both static and dynamic functions. Injuries of the posterolateral structures occur frequently in conjunction with ruptures of the posterior cruciate ligament. To investigate the role of the posterolateral structures in maintaining posterior knee stability, we measured thein situforces in the posterolateral structures and the distribution of force within the structures major components, i.e., the popliteus complex and the lateral collateral ligament, in response to a posterior tibial load. Eight cadaveric knees were tested. With use of a robotic/universal force‐moment sensor testing system, a posterior tibial load of 110 N was applied to the knee, and the resulting five‐degree‐of‐freedom kinematics were measured at flexion angles of 0, 30, 60, 75, and 90°. The knees were tested first in the intact state and then after the posterior cruciate ligament had been resected. These tests were also performed with an additional load of 44 N applied at the aponeurosis to simulate contraction of the popliteus muscle. In the intact knee, thein situforces in the posterolateral structures were found to decrease with increasing knee flexion. After the posterior cruciate ligament was sectioned, these forces increased significantly at all angles of flexion. With no load applied to the popliteus muscle, thein situforces in the popliteus complex were similar to those in the lateral collateral ligament. However, with a load of 44 N applied to the popliteus muscle,in situforces in the popliteus complex were three to five, times higher than those in the lateral collateral ligament. These results reveal that in response to posterior tibial loads, the posterolateral structures play an important role at full extension in intact knees and at all angles of flexion in posterior cruciate ligament‐deficient knees. The popliteus muscle appears to be a major stabilizer under this loading condition; thus, the inability to restore its function may be a cause of unsatisfactory results in reconstructive procedures of the posterolateral structures o

ISSN:0736-0266    

DOI:10.1002/jor.1100160608

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

年代:1998

数据来源: WILEY

摘要:

AbstractRehabilitation after soft‐tissue autograft reconstructions is controversial because there is indirect evidence that some grafts fail by creeping over time. The vulnerability of soft‐tissue grafts to creep over healing time and the effects of the load environment during healing on this vulnerability have never been studied specifically. We hypothesized that immobilization would decrease the magnitude of the vulnerability of ligament grafts to creep. Thirty‐nine skeletally mature New Zealand White rabbits underwent a standardized medial collateral ligament autograft procedure to the right hindlimb, and 19 of the rabbits also had the limb rigidly pinned into flexion. Subgroups were killed at 3 or 8 weeks, and all isolated tibia/medial collateral ligament/femur complexes were tested for creep at 4.1 MPa under a standardized protocol. Eight normal medial collateral ligament controls were tested similarly. Results showed that all grafts were quantitatively more susceptible to cyclic and static creep than were normal medial collateral ligament controls (p<0.05). By 3 weeks of healing, immobilization significantly increased the magnitude of the vulnerability of the grafts to cyclic, static, and total creep (all: p<0.05). Furthermore, the grafts had more unrecovered creep strain than did the controls following a 20‐minute recovery period. Contrary to our hypothesis, immobilization resulted in increased vulnerability of these ligament autografts to creep even with this relatively nonprovocative test of short duration and low stress. We postulate that following immobilization, this increase in the magnitude of susceptibility of the grafts to creep will result in functionally significant elongation of the graft if it is exposed to higher loads and over longer periods of time

ISSN:0736-0266    

DOI:10.1002/jor.1100160609

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

年代:1998

数据来源: WILEY

摘要:

AbstractThe present study, using confocal laser scanning microscopy and immunoelectron microscopy, examined the intracellular localization of tyrosine‐phosphorylated proteins in cultured mouse dorsal root ganglion neurons with special reference to their growth cones. The growth cone is the specialized structure formed at the growing tip of the axon; characteristically highly motile with filopodia on the surface, it is responsible for the extension and guidance of the neurites to the appropriate targets during nerve regeneration. It has been suggested that protein‐tyrosine phosphorylation plays an important role in the intracellular signal transduction that regulates the extension and motility of growth cones. By fluorescence immunocyto‐chemistry, phosphotyrosine immunoreactivity was found in the growth cones and neurites. Some of the filopodia exhibited strong immunoreactivity at their tips. By immunoelectron microscopy, a large number of immunogold particles (gold particles conjugated to the secondary antibody) were seen to be distributed in the cytoplasm and some were observed on the plasma membrane in the growth cones, whereas in the neurites the density of immunogold particles was the same in the axoplasm as on the plasma membranes. These findings suggest that in the growth cones phosphotyrosines might mainly be involved in intracellular signaling for maintaining their high motility whereas in the neurites they might mostly be associated with the receptor proteins at the plasma membrane for adhesion as well as for growth of neurites. Thus, tyrosine phosphorylation might contribute to different functions for growth cones and neu

ISSN:0736-0266    

DOI:10.1002/jor.1100160610

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

年代:1998

数据来源: WILEY

摘要:

AbstractThe anti‐inflammatory mediator interleukin‐10 was investigated as a potential inhibitor of pro‐inflammatory cytokine release in human peripheral blood monocytes activated with titanium particles. It inhibited the secretion of both tumor necrosis factor‐alpha and interleukin‐6 in a dose‐dependent manner, with complete inhibition observed at 2 ng/ml. Co‐culture experiments were performed to determine whether this cytokine may have functional importance as an inhibitor of the inflammatory response. When unstimulated lymphocytes and monocytes were co‐cultured with titanium‐stimulated monocytes, they significantly suppressed the secretion of both interleukin‐6 and tumor necrosis factor‐alpha. The inhibitory effect of these co‐cultured cells could be partially blocked with the addition of an interleukin‐10 neutralizing antibody. Interleukin‐10 levels were measured in monocyte cultures treated with titanium particles as well as in fresh monocyte cultures treated with conditioned medium from titanium‐stimulated monocytes. The latter experiments demonstrated marked stimulation of interleukin‐10 secretion in conditioned medium‐treated cultures, an effect that was related to the presence of tumor necrosis factor‐alpha in the conditioned medium. The addition of titanium to conditioned medium‐treated cultures markedly reduced the secretion of interleukin‐10, suggesting that the most responsive cells are unstimulated monocytes exposed to agents released from activated monocytes. Altogether, the expression and responsiveness to interleukin‐10 suggest a potential role for anti‐inflammatory cytokines in regulation

ISSN:0736-0266    

DOI:10.1002/jor.1100160611

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

年代:1998

数据来源: WILEY