| 1. |
- Forslund, Carina, et al.
(författare)
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A comparative dose-response study of cartilage-derived morphogenetic protein (CDMP)-1, -2 and -3 for tendon healing in rats
- 2003
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Ingår i: Journal of Orthopaedic Research. - 0736-0266 .- 1554-527X. ; 21:4, s. 617-621
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Tidskriftsartikel (refereegranskat)abstract
- Cartilage-derived morphogenetic proteins (CDMPs), belonging to the bone morphogenetic protein (BMP) family, are known to b cartilage and bone inducers as well as to induce tendon and ligament-like tissue. In this study we investigated the influence of CDMP-1, -2 or -3 at four different doses (0, 0.4, 2 and 10 ?g) on tendon healing in a rat model, as well as differences in osteogenesis between the different CDMPs and doses. In 110 rats, a 3 mm segment of the Achilles tendon was removed via a 2 mm skin incision. CDMP-1, -2 or -3 was injected into the defect 6 h postoperative. The rats were killed 8 days after operation. The tendon regenerates were tested biomechanically. There was a significant dose-related increase in strength and stiffness with all three CDMPs, but no difference between the CDMPs was found. Another 50 rats were used to compare the highest dose of the CDMPs with controls and osteogenic protein 1 (OP-1), as regards cartilage or bone formation after 4 weeks. Cartilage occurred in all groups, including the controls. Some specimens in all groups contained bone, except the controls. No difference between the CDMPs could be demonstrated. The CDMP-1, CDMP-3 and OP-1 groups contained significantly more calcium than controls. Only the CDMP-2 group and the controls contained significantly less calcium than the OP-1 group. In conclusion, the three CDMPs appeared similar as regards improvement of tendon repair and osteogenicity in this setting. ⌐ 2003 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
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| 2. |
- Forslund, Carina, et al.
(författare)
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CDMP-2 induces bone or tendon-like tissue depending on mechanical stimulation
- 2002
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Ingår i: Journal of Orthopaedic Research. - 0736-0266 .- 1554-527X. ; 20:6, s. 1170-1174
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Tidskriftsartikel (refereegranskat)abstract
- Cartilage derived morphogenetic proteins (CDMPs, also known as growth and differentiation factors, GDFs) are a subgroup of the bone morphogenetic protein (BMP) gene family. As most BMPs, they are known to induce cartilage or bone formation when implanted subcutaneously or intramuscularly on an appropriate carrier. However, similar implantation experiments with CDMPs have also reported the formation of a tendon-like tissue, without any cartilage or bone. A solution to this apparent contradiction might be offered by the mechanical tissue differentiation theory, suggesting that tissue differentiation depends on the mechanical environment. This study analyzes the response to CDMP-2 implants at different sites and under different loading conditions in the rat. Collagen sponges carrying CDMP-2 were implanted subcutaneously, intramuscularly or inside a freshly created defect in the achilles tendon. Large amounts of bone were induced subcutaneously, smaller amounts intramuscularly, and in the tendons, only small amounts of bone or cartilage were seen in few animals. Thus, the amount of bone appeared inversely related to the degree of mechanical stimulus. To confirm this, CDMP was also injected into tendon defects that were either loaded or partially unloaded. All the unloaded tendons showed bone induction after one CDMP-2 injection, whereas only 4 of 10 loaded ones showed any cartilage or bone (p = 0.0005). Single injections of a similar dose of CDMP-2 have previously been shown to augment tendon repair by increasing the size of the tendon callus. This study suggests that the response to CDMP-2 is dependent on the mechanical situation at the site where it is applied. ⌐ 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
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| 3. |
- Skoglund, Björn, 1975-, et al.
(författare)
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PMMA particles and pressure - A study of the osteolytic properties of two agents proposed to cause prosthetic loosening
- 2003
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Ingår i: Journal of Orthopaedic Research. - 0736-0266 .- 1554-527X. ; 21:2, s. 196-201
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Tidskriftsartikel (refereegranskat)abstract
- Amongst the wear debris particles implicated in the particle hypothesis for prosthetic loosening are polymethylmethacrylate (PMMA), and particularly PMMA with barium sulphate contrast agent. Another suggested cause for loosening is hydrostatic pressure. PMMA particles were combined with hydrostatic pressure in a study to investigate whether there could be a synergistic or additive effect between these two factors. Titanium plates were fastened onto tibiae of 59 rats. After osseointegration, PMMA particles with barium sulphate were administered to the bone-implant interface. Further, PMMA particles were introduced into a previously published model for hydrostatic pressure induced osteolysis. There was measurable resorption in response to the PMMA particles but no additive or synergistic effect from introducing particles to the pressure model, and the effect of pressure was far greater than that of particles. These results suggest that, whereas particles can be shown to elicit an osteolytic response, the much less studied osteolytic effects of pressure could be far more important. ⌐ 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
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| 4. |
- Alfredson, Håkan, et al.
(författare)
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cDNA-arrays and real-time quantitative PCR techniques in the investigation of chronic Achilles tendinosis.
- 2003
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Ingår i: Journal of Orthopaedic Research. - 0736-0266 .- 1554-527X. ; 21:6, s. 970-975
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Tidskriftsartikel (refereegranskat)abstract
- The aetiology and pathogenesis of chronic painful Achilles tendinosis are unknown. This investigation aimed to use cDNA arrays and real-time quantitative polymerase chain reaction (real-time PCR) technique to study tendinosis and control tissue samples. Five patients (females mean age 57.1+/-4.3 (years+/-SD)) with chronic painful Achilles tendinosis were included. From all patients, one biopsy was taken from the area with tendinosis and one from a clinically normal area (control) of the tendon. The tissue samples were immediately immersed in RNAlater and frozen at -80 degrees C until RNA extraction. Portions of pooled RNA from control and tendinosis sites, respectively, were transcribed to cDNA, radioactively labelled (32P), hybridized to cDNA expression arrays, and exposed to phosphoimager screens over night. Expressions of specific genes, shown to be regulated in the cDNA array analysis, were analyzed in the individual samples using real-time PCR. cDNA arrays showed that gene expressions for matrix-metalloproteinase-2 (MMP-2), fibronectin subunit B (FNRB), vascular endothelial growth factor (VEGF), and mitogen-activated protein kinase p38 (MAPKp38) were up-regulated, while matrix-metalloproteinase-3 (MMP-3) and decorin were down-regulated, in tendinosis tissue compared with control tissue. Using real-time PCR, 4/5 and 3/5 patients showed up-regulation of MMP-2 and FNRB mRNA, respectively. For decorin, VEGF, and MAPKp38, real-time PCR revealed a great variability among patients. Interestingly, the mRNAs for several cytokines and cytokine receptors were not regulated, indicating the absence of an inflammatory process in chronic painful Achilles tendinosis. In conclusion, cDNA-arrays and real-time PCR can be used to study differences in gene expression levels between tendinosis and control tendon tissue.
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| 5. |
- Alfredson, Håkan, et al.
(författare)
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High intratendinous lactate levels in painful chronic Achilles tendinosis. An investigation using microdialysis technique.
- 2002
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Ingår i: Journal of Orthopaedic Research. - 0736-0266 .- 1554-527X. ; 20:5, s. 934-938
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Tidskriftsartikel (refereegranskat)abstract
- In this investigation the microdialysis technique was used to study the concentrations of lactate in Achilles tendons with painful chronic tendinosis and in normal pain-free tendons. In four patients (mean age 40.7 years) with a painful thickening localized at the 2-6 cm level in the Achilles tendon (chronic Achilles tendinosis) and in five controls (mean age 37.2 years) with normal Achilles tendons the local concentrations of lactate were registered under resting conditions. All tendons were examined using ultrasonography. In the tendons with tendinosis the painful thickening corresponded to a widened tendon and structural tendinosis changes. Normal tendons showed no widening and a normal structure. A standard microdialysis catheter was inserted into the Achilles tendon under local anesthesia. Samplings were done every 15 min during a 4 h period. The results showed significantly higher mean concentrations of lactate in tendons with tendinosis compared to normal tendons (2.15 mmol/l vs. 1.14 mmol/l). The lactate concentrations in the tendons with tendinosis were stable, and approximately twofold higher than in the normal tendons during the whole 4 h investigation period. In conclusion, the higher concentrations of lactate in Achilles tendons with painful tendinosis indicate that there are anaerobic conditions in the area with tendinosis. The importance of this finding for the pathogenesis and pain mechanisms in this chronic condition needs to be further investigated.
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| 6. |
- Alfredson, Håkan, et al.
(författare)
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In vivo microdialysis and immunohistochemical analyses of tendon tissue demonstrated high amounts of free glutamate and glutamate NMDAR1 receptors, but no signs of inflammation, in Jumper's knee.
- 2001
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Ingår i: Journal of Orthopaedic Research. - 0736-0266 .- 1554-527X. ; 19:5, s. 881-886
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Tidskriftsartikel (refereegranskat)abstract
- This investigation describes, to our knowledge, the first experiment where the microdialysis technique was used to study certain metabolic events in human patellar tendons in combination with immunohistochemical analyses of tendon biopsies. In five patients (four men and one woman) with a long duration (range 12-36 months) of pain symptoms from Jumper's knee (localized tenderness in the patellar tendon verified as tendon changes with ultrasonography or MRI), and in five controls (four men and one woman) with normal patellar tendons, a standard microdialysis catheter was inserted into the patellar tendon under local anestesia. The local concentrations of glutamate (excitatory neurotransmitter) and prostaglandin E2 (PGE2) were registered under resting conditions. Samplings were done every 15 min during a 2 h period. In all individuals (patients and controls) biopsies were taken for immunohistochemical analyses. The results showed that it was possible to detect and measure the concentrations of glutamate and PGE2 in the patellar tendon with the use of microdialysis technique. There were significantly higher concentrations of free glutamate, but not PGE2, in tendons with tendinosis compared to normal tendons. In the biopsies, there were no inflammatory cell infiltrates, but, for the first time, it was shown that there was immunoreaction for the glutamate receptor NMDAR1 in association with nerve structures in human patellar tendons. These findings altogether indicate that glutamate might be involved in painful Jumper's knee, and further emphasizes that there is no chemical inflammation (normal PGE2 levels) in this chronic condition.
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| 7. |
- Bergström, Jonas, et al.
(författare)
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Purification and quantification of opioid peptides in bone and joint tissues : a methodological study in the rat
- 2003
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Ingår i: Journal of Orthopaedic Research. - 0736-0266 .- 1554-527X. ; 21:3, s. 465-469
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Tidskriftsartikel (refereegranskat)abstract
- The occurrence of methionine-enkephalin-Arg(6)-Phe(7) (MEAP) and dynorphin B (DYNB) representing two main precursors of opioids was analyzed in specimens from rat cortical bone, periosteum, bone marrow and joint tissue by radioimmunoassay (RIA). MEAP and DYNB were extracted in a solution of 4% EDTA in 2 M acetic acid previously proven suitable for extraction of sensory and autonomic neuropeptides in bone and joints. In crude extracts of cortical bone, the immunoreactive (ir) levels of both opioids were under the detection limit of RIA. As for DYNB this also applied to crude extracts of joints and periosteum. Therefore, two purification methods were tested and compared, i.e. reverse phase C 18 and ion exchange chromatography. RIA of the elution fraction disclosed a significant difference between the two methods in terms of recovery, i.e. <5% and 50%, respectively. Thus, purification by ion exchange chromatography prior to RIA appeared to be the most suitable by providing measurable levels of both MEAP and DYNB in all tissues analyzed (highest in bone marrow, lowest in cortical bone). The described method offers a means of quantifying opioid peptides in bone and joints, which may be utilized in the analysis of regulatory mechanisms of nociception, growth and immune responses in different conditions.
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| 8. |
- Tillander, Bo, et al.
(författare)
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Fibronectin, MMP-1 and histologic changes in rotator cuff disease
- 2002
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Ingår i: Journal of Orthopaedic Research. - 0736-0266 .- 1554-527X. ; 20:6, s. 1358-1364
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Tidskriftsartikel (refereegranskat)abstract
- This study was designed to investigate human surgical specimens from patients with impingement (n = 16), ruptured supraspinatus tendons (n = 7), frozen shoulder (n = 2) and controls (n = 9) with respect to histological changes and the presence of fibronectin and Matrix metalloprotease-1 (MMP-1). The biopsy of the middle part of the supraspinatus tendons was analyzed microscopically after staining with hematoxyline eosin, Van Giesons hematoxyline and Phospho Tungstic Acid Hematoxyline for visualization of fibrin. Immunofluorescent stainings for fibronectin and MMP-1 were performed. Histology and immunofluorescence were assessed blindly. Necrotic tendinous tissue and fibrin were found only in some specimens from ruptures. The staining for fibronectin was significantly increased among patients with a rupture. MMP-1 was, however, only infrequently found in specimens from patients with impingement and ruptures. Fibrosis and thinning of fascicles seemed to be a more non-specific finding, appearing in control, impingement and rupture specimens. In conclusion, necrotic tendinous tissue, fibrin and fibronectin appear to be signs of tendon degeneration, whereas fibrosis and thinning of fascicles were found also in controls. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
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| 9. |
- Agholme, Fredrik, et al.
(författare)
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Efficacy of a Sclerostin Antibody Compared to a Low Dose of PTH on Metaphyseal Bone Healing
- 2014
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Ingår i: Journal of Orthopaedic Research. - : Wiley-Blackwell. - 0736-0266 .- 1554-527X. ; 32:3, s. 471-476
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Tidskriftsartikel (refereegranskat)abstract
- We compared the effect of a sclerostin antibody to that of a clinically relevant dose of parathyroid hormone (PTH) in a rat model for metaphyseal bone healing. Screws of steel or poly methyl methacrylate (PMMA) were inserted bilaterally into the proximal tibia of young male rats. During 4 weeks the animals then received injections of either phosphate buffered saline (control), sclerostin antibody (25mg/kg, twice weekly) or PTH (5 mu g/kg, daily). The healing response around the screws was then assessed by mechanical testing and X-ray microtomography (mu CT). To distinguish between effects on healing and general effects on the skeleton, other untraumatized bone sites and serum biomarkers were also assessed. After 4 weeks of treatment, PTH yielded a 48% increase in screw pull-out force compared to control (p=0.03), while the antibody had no significant effect. In contrast, the antibody increased femoral cortical and vertebral strength where PTH had no significant effect. mu CT showed only slight changes that were statistically significant for the antibody mainly at cortical sites. The results suggest that a relatively low dose of PTH stimulates metaphyseal repair (screw fixation) specifically, whereas the sclerostin antibody has wide-spread effects, mainly on cortical bone, with less influence on metaphyseal healing.
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| 10. |
- Almquist, Per Otto, et al.
(författare)
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Knee rotation in healthy individuals related to age and gender.
- 2012
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Ingår i: Journal of Orthopaedic Research. - : Wiley. - 1554-527X .- 0736-0266.
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Tidskriftsartikel (refereegranskat)abstract
- An external device ("the Rottometer") was especially designed to measure passive knee rotation in vivo. The device had earlier been evaluated with respect to it's validity and reliability. In the present study, we evaluated knee rotation in knee-healthy individuals and studied possible age and gender related differences. Measurements of total internal-external rotation were made at 90°, 60°, and 30° of flexion using 6 and 9 N m torques, as well as the examiner's apprehension of end-feel as displacing forces. The study group constituted of 120 healthy subjects (60 females and 60 males) with no prior or present knee disorders. The sample was divided into four age groups (15-30, 31-45, 46-60, and >60 years). The results showed no differences in knee rotation between the right and left knees or between the different flexion angles. The females showed 10-20% (p < 0.01) larger knee rotation than the males at all the three flexion angles and at all the three applied torques in all age-matched groups. In all age groups in both genders, the internal rotation accounted for 40-44% and the external for 56-60% of the total internal-external knee rotation. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.
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| 11. |
- Andersson, Therese, et al.
(författare)
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Achilles tendon healing in rats is improved by intermittent mechanical loading during the inflammatory phase
- 2012
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Ingår i: Journal of Orthopaedic Research. - : Wiley Online Library. - 0736-0266 .- 1554-527X. ; 30:2, s. 274-279
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Tidskriftsartikel (refereegranskat)abstract
- Tendons adapt to changes in mechanical loading, and numerous animal studiesshow that immobilization of a healing tendon is detrimental to the healingprocess. The present study addresses whether the effects of a few episodes ofmechanical loading are different during different phases of healing. Fifty femalerats underwent Achilles tendon transection, and their hind limbs were unloadedby tail suspension on the day after surgery. One group of 10 rats was taken downfrom suspension to walk on a treadmill for 30 minutes per day, on days 2-5 aftertransection. They were euthanized on day 8. Another group underwent similartreadmill running on days 8-11 and was euthanized on day 14. Completelyunloaded groups were euthanized on day 8 and 14. Tendon specimens were thenevaluated mechanically. The results showed that just 4 loading episodesincreased the strength of the healing tendon. This was evident irrespective of thetime-point when loading was applied (early or late). The positive effect on earlyhealing was unexpected, considering that the mechanical stimulation was appliedduring the inflammatory phase, when the calluses were small and fragile. Ahistological study of additional groups with early loading also showed someincreased bleeding in the loaded calluses. Our results indicate that a smallamount of early loading may improve the outcome of tendon healing. This couldbe of interest to clinical practice.
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| 12. |
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| 13. |
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| 14. |
- Aspenberg, P., et al.
(författare)
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Monkey bone matrix induces bone formation in the athymic rat, but not in adult monkeys
- 1991
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Ingår i: Journal of Orthopaedic Research. - : Wiley. - 0736-0266 .- 1554-527X. ; 9:1, s. 20-25
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Tidskriftsartikel (refereegranskat)abstract
- Demineralized bone matrix from young and adult monkeys was implanted intramuscularly for 6 weeks in athymic rats and adult monkeys. Cartilage and bone induction was evaluated by histology and calcium content. In the athymic rat, most implants induced cartilage or bone. In the monkeys, cartilage was formed only on rare occasions and there was no sign of bone formation. We conclude that (a) adult monkey bone matrix contains bone inductive properties; (b) these properties are not sufficient to induce bone formation in adult monkey muscle sites.
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| 15. |
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| 16. |
- Berglund, Maria, 1975-, et al.
(författare)
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Growth Factor and Protease Expression during Different Phases of Healing after Rabbit Deep Flexor Tendon Repair
- 2011
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Ingår i: Journal of Orthopaedic Research. - : Wiley. - 0736-0266 .- 1554-527X. ; 29:6, s. 886-892
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of the study was to contribute to the mapping of molecular events during flexor tendon healing, in particular the growth factors insulin-like growth factor-1 (IGF-1), vascular endothelial growth factor (VEGF) and nerve growth factor (NGF), matrix metalloproteinases (MMP-3 and MMP-13) and their inhibitors (tissue inhibitors of metalloproteinases, TIMP-1 and TIMP-3, and the protease cathepsin K. In a rabbit model of flexor tendon injury, the mRNA expression for the growth factors, MMPs and TIMPs were measured in tendon and tendon sheath tissue at several time points (3, 6, 21, and 42 days) representing different phases of the healing process. We found that MMP-13 remained increased during the study period, whereas MMP-3 returned to normal levels within the first week after injury. TIMP-3 was down-regulated in the tendon sheaths. Cathepsin K was up-regulated in tendons and sheaths after injury. NGF was present in both tendons and sheaths, but unaltered. IGF-1 exhibited a late increase in the tendons, while VEGF was down-regulated at the later time points. In conclusion, we have demonstrated the presence of NGF in flexor tendons. MMP-13 expression appears to play a more protracted role in flexor tendon healing than MMP-3. The relatively low levels of endogenous IGF-1 and VEGF mRNA following injury support their potential beneficial role as exogenous modulators to optimize tendon healing and strength without increasing adhesion formation.
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| 17. |
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| 18. |
- Bernhardsson, Magnus, 1989-, et al.
(författare)
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Depletion of cytotoxic (CD8+) T cells impairs implant fixation in rat cancellous bone
- 2019
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Ingår i: Journal of Orthopaedic Research. - : John Wiley & Sons. - 0736-0266 .- 1554-527X. ; 37:4, s. 805-811
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Tidskriftsartikel (refereegranskat)abstract
- As cytotoxic (CD8(+)) T cells seem to impair shaft fracture healing, we hypothesized that depletion of CD8(+) cells would instead improve healing of cancellous bone. Additionally, we also tested if CD8-depletion would influence the healing of ruptured Achilles tendons. Rats received a single injection of either anti-CD8 antibodies or saline and put through surgery 24 h later. Three different surgical interventions were performed as follows: (1) a drill hole in the proximal tibia with microCT (BV/TV) to assess bone formation; (2) a screw in the proximal tibia with mechanical evaluation (pull-out force) to assess fracture healing; (3) Achilles tendon transection with mechanical evaluation (force-at-failure) to assess tendon healing. Furthermore, CD8-depletion was confirmed with flow cytometry on peripheral blood. Flow cytometric analysis confirmed depletion of CD8(+) cells (p amp;lt; 0.001). Contrary to our hypothesis, depletion of CD8(+) cells reduced the implant pull-out force by 19% (p amp;lt; 0.05) and stiffness by 34% (p amp;lt; 0.01), although the bone formation in the drill holes was the same as in the controls. Tendon healing was unaffected by CD8-depletion. Our results suggest that CD8(+) cells have an important part in cancellous bone healing.
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| 19. |
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| 20. |
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| 21. |
- Bojan, Alicja J., 1980, et al.
(författare)
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Three-dimensional bone-implant movements in trochanteric hip fractures. Precision and accuracy of radiostereometric analysis in a phantom model.
- 2015
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Ingår i: Journal of orthopaedic research : official publication of the Orthopaedic Research Society. - : Wiley. - 1554-527X. ; 33:5, s. 705-11
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Tidskriftsartikel (refereegranskat)abstract
- The accuracy and precision of RSA was evaluated in the experimental study of screw cut-out complication after fixation of trochanteric fractures. A plastic bone model of a two-part trochanteric fracture was constructed with a Gamma nail implant incorporating RSA markers. The femoral head fragment was attached to a separate rotational table and the femoral shaft was mounted on the micrometer. Three main motions were simulated: femoral head translation and rotation along the axis of the lag screw and fracture fragment translation along anatomical axes. Accuracy and precision were determined according to ISO 16087 and ASTM standard F2385-04. Translations along the lag screw axis were measured with a precision within±0.14mm and an accuracy within±0.03mm. With simultaneous translations along all three anatomical axes, lowest precision was measured for the x-axis (±0.29mm, 0.07mm respectively), but improved when analyzed as a vector (±0.08mm, 0.03mm). The precision and accuracy of femoral head rotations were within 0.5° and 0.18°, respectively. The resolution of the RSA method tested in this model was high, though it varied depending on the type of analyzed motion. This information is valuable when selecting and interpreting outcome parameters evaluating implant migration and osteosynthesis stability in future clinical RSA studies. This article is protected by copyright. All rights reserved.
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| 22. |
- Bosemark, Per, et al.
(författare)
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Influence of systemic bisphosphonate treatment on mechanical properties of BMP-induced calluses in a rat fracture model: Comparison of three-point bending and twisting test.
- 2014
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Ingår i: Journal of Orthopaedic Research. - : Wiley. - 1554-527X .- 0736-0266. ; 32:5, s. 721-726
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Tidskriftsartikel (refereegranskat)abstract
- The combination of autograft, BMP and bisphosphonate has been shown to produce strong calluses. In this study, without autograft we investigate the effect of bisphosphonate treatment on BMP-induced calluses, both in bending and in rotation. Sprague-Dawley rats (n = 42) underwent femoral osteotomy and BMP-7 treatment. At 2 weeks an injection of saline or bisphosphonate was administered. The animals were sacrificed after 6 weeks. Both femurs were tested in either three-point bending or twisting. All femurs healed. BMP + bisphosphonate-treatment led to larger calluses (p < 0.05) and in three-point bending, higher ultimate force (p < 0.01) and greater stiffness (p < 0.05) than BMP alone. The BMP + bisphosphonate group was nearly 60% stronger than controls, while the BMP group did not reach the strength (p < 0.05) nor stiffness (p < 0.01) of the controls. In the twisting test, similar trends were found but less pronounced. Three-point bending produced transverse callus associated fractures, whereas the twisting test produced spiral fractures, located in the structurally weaker distal femur. BMP + bisphosphonate-treatment produces calluses that are mechanically superior to calluses induced by BMP alone, when tested both in three-point bending and in twisting. For the mechanical evaluation of pharmacologically enhanced calluses with breaking strengths exceeding the native bone, the bending test is recommended. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.
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| 23. |
- Bosemark, Per, et al.
(författare)
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The Masquelet Induced Membrane Technique with BMP and a Synthetic Scaffold Can Heal a Rat Femoral Critical Size Defect.
- 2015
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Ingår i: Journal of Orthopaedic Research. - : Wiley. - 1554-527X .- 0736-0266. ; 33:4, s. 488-495
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Tidskriftsartikel (refereegranskat)abstract
- Long bone defects can be managed by the induced membrane technique together with autologous bone graft. However, graft harvest is associated with donor site morbidity. This study investigates if a tricalcium phosphate hydroxyapatite scaffold can be used alone or in combination with bone active drugs to improve healing. Sprague Dawley rats (n = 40) were randomized into four groups. (A) scaffold, (B) BMP-7, (C) BMP-7 + scaffold, and (D) BMP-7 + scaffold + systemic bisphosphonate at 2 weeks. Locked femoral nailing was followed by 6 mm segment removal and implantation of an epoxy spacer. At 4 weeks, the spacers were removed and the defects grafted. Eleven weeks later, the bones were explanted for evaluation with radiography, manual assessment, micro-CT, histology, and Fourier Transform Infrared spectroscopy (FTIR). Isolated scaffolds (A) did not heal any defects, whereas the other treatments led to healing in 7/10 (B), 10/10 (C), and 9/10 (D) rats. Group D had greater volume of highly mineralized bone (p < 0.01) and higher bone volume fraction (p < 0.01) compared to all other groups. A synthetic scaffold + BMP-7 combined with a bisphosphonate improved the callus properties in a rat femoral critical size defect, compared to both BMP-7 and scaffold alone or the two combined. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.
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| 24. |
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| 25. |
- Bragdon, Charles R, 1959, et al.
(författare)
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Comparison of two digital radiostereometric analysis methods in the determination of femoral head penetration in a total hip replacement phantom
- 2004
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Ingår i: J Orthop Res. - : Wiley. - 0736-0266. ; 22:3, s. 659-64
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Tidskriftsartikel (refereegranskat)abstract
- Radiostereometric analysis (RSA) has been used extensively to evaluate the magnitude and direction of penetration of the femoral head into the acetabular component of a total hip replacement as a result of polyethylene wear and creep. The accuracy and precision of an RSA study depends on several factors, including the radiographic technique, the analytical software, and the positioning of the tantalum markers. This study had three sequential purposes. First, an in vitro phantom model was used to quantify the accuracy and precision of digital images versus conventional radiography in RSA measurements of penetration of the femoral head into the acetabular shell in a total hip replacement. The Umea RSA software package was used for analysis of both the conventional films, which were digitized at a resolution of 300 DPI, and digital radiographs, which were converted from a DICOM format at a resolution of 218 DPI. Digital radiography was found to be superior. Next, two methods of RSA analysis currently in use for determining femoral head penetration into polyethylene of total joint replacements were compared. Using the phantom model, we compared the Umea RSA system (Biomedical Innovations AB) to the RSA-CMS (RSA Clinical Measurement Solution) and in both cases used the digital radiographs. The Umea RSA system was found to be superior. Finally, two methods of marking the position of the acetabular component with tantalum beads were compared: one in which beads were inserted into previously described towers protruding from the back of the acetabular shell and another in which beads were placed into the peripheral flange of the polyethylene liner using the Umea RSA analysis system of the digital radiographs. The results using the two marker configurations were similar.
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