| 238581. |
- Röhrl, Stephan M, et al.
(author)
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No adverse effects of submelt-annealed highly crosslinked polyethylene in cemented cups : an RSA study of 8 patients 10 years after surgery
- 2012
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In: Acta Orthopaedica. - : Informa Healthcare. - 1745-3674 .- 1745-3682. ; 83:2, s. 148-152
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Journal article (peer-reviewed)abstract
- Background and purpose Highly crosslinked polyethylene (PE) is in standard use worldwide. Differences in the crosslinking procedure may affect the clinical performance. Experimenatal data from retrieved cups have shown free radicals and excessive wear of annealed highly crosslinked PE. We have previously reported low wear and good clinical performance after 6 years with this implant, and now report on the 10-year results. Patients and methods In 8 patients, we measured wear of annealed highly crosslinked PE prospectively with radiostereometry after 10 years. Activity was assessed by UCLA activity score and a specifically designed activity score. Conventional radiographs were evaluated for osteolysis and clinical outcome by the Harris hip score (HHS). Results The mean (95% CI) proximal head penetration for highly crosslinked PE after 10 years was 0.07 (-0.015 to 0.153) mm, and the 3D wear was 0.2 (0.026 to 0.36) mm. Without creep, proximal head penetration was 0.02 (-0.026 to 0.066) mm and for 3D penetration was 0.016 (-0.47 to 0.08) mm. This represents an annual proximal wear of less than 2 mu m. All cups were clinically and radiographically stable but showed a tendency of increased rotation after 5 years. Interpretation Wear for annealed highly crosslinked PE is extremely low up to 10 years. Free radicals do not affect mechanical performance or lead to clinically adverse effects. Creep stops after the first 6 months after implantation. Highly crosslinked PE is a true competitor of hard-on-hard bearings.
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| 238582. |
- Röhrl, Stephan Maximilian, 1966-
(author)
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Wear and Fixation of the acetabular component : in vivo evaluation of different polyethylenes and modes of fixation in total hip arthroplasty
- 2004
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Doctoral thesis (other academic/artistic)abstract
- Polyethylene wear and micromotion of the implant play an important role in multifactorial etiology of osteolysis leading to aseptic loosening of the acetabular components. Despite excellent results in primary total hip arthoplasty in a 10-15 year perspective there are still unsolved problems. The weakest link is the longevity of the actabular component. Young and active patients have a clearly worse outcome than older patients. Consequences of polyehtylene wear and ways to reduce wear have therefore been in focus during recent years. Radiostereometry (RSA) is the golden standard in measuring in vivo micromotions. In 4 clinical studies including 332 patients we used therefore RSA to record the efficacy of fixation of cemented and uncemented cups. The amount of wear of old and newly designed polyethylenes (PE) was related to cup stability and radiological and clinical measures of outcome. This study showed that cementless cups inserted with pressfit technique do not need additional augmentation. Screws and pegs increase the risk for radiolucencies and osteolystic lesions but are helpful tools in cases where primary stability is jeopardized. In the second decade clinically silent osteolysis is common for the porous coated Harris Galante cup with unsealed screw holes. The locking mechanism of the PE liner in this cup is unsatisfactory and an increase of liner dissociations is expected. EtO sterilized PE displayed high in vivo wear and we do not recommend its continued use but close monitoring of patients with earlier inserted EtO sterilized implants. The substantially reduced wear in cemented highly cross-linked PE cups without any negative in vivo tradeoffs might have a substantial impact on choice of material and operating technique in the near future. However, we still recommend its restrained use in controlled series until longer follow-up data is available. Nevertheless, the short term in vivo results of modern highly cross-linked PE look promising and ight improve the outcome of cemented and uncemented hip arthroplasties by reducing complication and revisions.
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| 238583. |
- Röhrl, Stephan, et al.
(author)
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Migration pattern of a short femoral neck preserving stem
- 2006
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In: Clinical Orthopaedics and Related Research. - : Wolters Kluwer. - 0009-921X .- 1528-1132. ; 448:July, s. 73-78
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Journal article (peer-reviewed)abstract
- AB The CFP stem represents a short collared neck-retaining stem with very proximal metaphyseal anchoring along the calcar combined with up-to-date metallurgy. Despite theoretical advantages, the stability and clinical outcome are unknown. We prospectively measured the migration pattern of this new stem and cup. Twenty-six patients (26 hips) with a mean age of 54 years (range, 40-66 years) underwent THA and were followed for 2 years with radiostereometry, radiographs, and clinical scores. The stem showed some early retroversion (mean, SEM 0.6[degrees], 0.3), but stabilized before 1 year. Subsidence (0.05 mm, 0.06) and varus-valgus tilting (0.03[degrees], 0.01) were low. We observed no bone loss in the calcar region. Factors related to patients, implant design, and implantation did not predict migration patterns. The two-dimensional wear of the ceramic/conventional articulation was 0.09 mm at 2-24 months. The low migration of this short neck preserving stem suggests a favorable long-term outcome but longer followup is needed to substantiate this prediction. This design might become an alternative to standard stems and hip resurfacing. Level of Evidence: Therapeutic Level IV. See The Guidelines for Authors for a complete description of levels of evidence.
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| 238584. |
- Röijezon, Ulrik, et al.
(author)
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Ländryggen
- 2019. - 1
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In: Motorisk kontroll och inlärning. - : Studentlitteratur AB. - 9789144074177 ; , s. 215-228
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Book chapter (peer-reviewed)
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| 238585. |
- Röjler, Lovisa, 1983-
(author)
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Eosinophilic esophagitis and disease complications : register-based studies
- 2023
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Doctoral thesis (other academic/artistic)abstract
- This thesis presents four studies on Eosinophilic Esophagitis (EoE). The overall aim is to grasp the basics of epidemiologic research and use this understanding on EoE disease complications. EoE is a fairly new inflammatory disease with clinicopathological diagnosis that increases in prevalence. It is considered a relatively mild disease, but the evidence concerning mortality and morbidity is scarce. Although EoE has a prevalence peak in childbearing age, pregnancy outcomes are poorly examined. In Study I, a random portion of 131 patient charts from the cohort werecollected for a diagnosis validation through a patient chart review. EoE was found in 99 patients, which corresponds to a positive predictive value of 89%. The cohort was predominately male, and the most common symptom was dysphagia. Study II examines mortality in EoE individuals compared to matched reference individuals using survival analysis. We performed sibling analysis to adjust for intrafamilial (genetic and environmental) confounding. We found no elevated risk for death. Study III uses a similar method to find higher risk of psychiatric comorbidity among EoE patients compared to matched reference individuals. Mean follow-up time was 4.03 years, and there were 106 events of psychiatric disease in the EoE-group, which corresponds to an elevated risk of 50% compared to reference individuals. Study IV investigates outcomes of pregnancy in EoE females versus comparators. The main outcome is premature birth; in secondary analyses, we examined both maternal and fetal outcomes. The only elevated risk was low birth weight; although a significant finding, it was still based on a small sample size and should be interpreted with caution.
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| 238586. |
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| 238587. |
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| 238588. |
- Röme, Andrada, et al.
(author)
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p38 Mitogen-activated protein kinase signalling regulates vascular inflammation and epithelial barrier dysfunction in an experimental model of radiation-induced colitis.
- 2010
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In: British Journal of Surgery. - : Oxford University Press (OUP). - 1365-2168 .- 0007-1323. ; 97, s. 226-234
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Journal article (peer-reviewed)abstract
- BACKGROUND:: Microvascular injury and epithelial barrier dysfunction are rate-limiting aspects in radiation enteropathy. This study examined the role of p38 mitogen-activated protein kinase (p38 MAPK) signalling in radiation-induced colitis in an experimental model. METHODS:: The p38 MAPK inhibitor SB239063 was administered to mice immediately before exposure to 20 Gy radiation. Leucocyte- and platelet-endothelium interactions in the colonic microcirculation were assessed by intravital microscopy. Levels of myeloperoxidase (MPO) and CXC chemokines (macrophage inflammatory protein (MIP) 2 and cytokine-induced neutrophil chemoattractant (KC)), and albumin leakage were quantified 16 h after irradiation. RESULTS:: Irradiation induced an increase in leucocyte and platelet recruitment, MPO activity, CXC chemokine levels and intestinal leakage. Inhibition of p38 MAPK by SB239063 decreased radiation-induced leucocyte and platelet recruitment (leucocyte rolling and adhesion by 70 and 90 per cent, both P < 0.001; that of platelets by 70 and 74 per cent, both P < 0.001). It also reduced radiation-provoked increases in colonic MPO activity by 88 per cent (P < 0.001), formation of MIP-2 and KC by 72 and 74 per cent respectively (P = 0.003 and P < 0.001), and intestinal leakage by 81 per cent (P < 0.001). CONCLUSION:: p38 MAPK is an important signalling pathway in radiation-induced colitis. Copyright (c) 2009 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd.
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| 238589. |
- Röme, Andrada, et al.
(author)
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Radiation-induced platelet-endothelial cell interactions are mediated by P-selectin and P-selectin glycoprotein ligand-1 in the colonic microcirculation.
- 2012
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In: Surgery. - : Elsevier BV. - 1532-7361 .- 0039-6060. ; 151:4, s. 606-611
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Journal article (peer-reviewed)abstract
- BACKGROUND: Antiplatelet reagents have been reported to protect against intestinal damage associated with abdominal radiotherapy, but the mechanisms behind radiation-induced platelet-endothelium interactions are not known. We sought to define the adhesive mechanisms that regulate radiotherapy-induced platelet-endothelial cell interactions in the colon. METHODS: All mice except the controls were exposed to abdominal radiation with a single dose of 20 Gray. Mice were pretreated with an isotype-matched control antibody or a monoclonal antibody directed against either P-selectin or P-selectin glycoprotein ligand-1 (PSGL-1). Platelet and leukocyte rolling and adhesion in the colon were determined by use of inverted intravital fluorescence microscopy 16 hours after radiation. Radiation-induced intestinal leakage of fluorescein isothiocyanate-conjugated dextran was examined in separate experiments. RESULTS: Immunoneutralization of P-selectin decreased radiation-provoked platelet rolling by 87% and adhesion by 63%. Moreover, inhibition of PSGL-1 decreased platelet rolling and adhesion by 77% and 83%, respectively, in animals exposed to radiation. Similarly, inhibition of P-selectin and PSGL-1 decreased radiation-induced leukocyte rolling and adhesion by more than 84% and 90%, respectively, in the colon. In contrast, inhibition of P-selectin or PSGL-1 had no impact on radiation-induced intestinal leakage. In addition, systemic depletion of platelets and leukocytes did not affect intestinal barrier dysfunction in radiated animals. CONCLUSION: This study demonstrates that radiation-provoked platelet and leukocyte accumulation are mediated in part by P-selectin and PSGL-1. Radiation-induced gut leakage, however, is independent of accumulation of platelets and leukocytes in the intestinal microvasculature.
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| 238590. |
- Röme, Andrada, et al.
(author)
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Rho kinase signalling mediates radiation-induced inflammation and intestinal barrier dysfunction.
- 2011
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In: British Journal of Surgery. - : Oxford University Press (OUP). - 1365-2168 .- 0007-1323. ; 98, s. 124-131
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Journal article (peer-reviewed)abstract
- BACKGROUND:: Radiotherapy is important in the management of pelvic malignancies, but radiation-induced intestinal damage is a dose-limiting factor. Microvascular injury and epithelial barrier dysfunction are considered to be rate-limiting aspects in radiation-induced enteropathy. This study investigated the role of Rho kinase signalling in radiation-induced inflammation and intestinal barrier dysfunction. METHODS:: The specific Rho kinase inhibitor Y-27632 (1 and 10 mg/kg) was given to C57BL/6J mice before challenge with 20 Gy radiation. Leucocyte- and platelet-endothelium interactions in the colonic microcirculation were assessed by intravital microscopy. Levels of myeloperoxidase (MPO) and CXC chemokines (macrophage inflammatory protein 2 and cytokine-induced neutrophil chemoattractant), and intestinal leakage were quantified after 16 h. RESULTS:: Radiation increased leucocyte and platelet recruitment, MPO activity, CXC chemokine production and intestinal leakage. Y-27632 significantly reduced radiation-induced leucocyte rolling and abolished adhesion; it also decreased platelet rolling and adhesion by 55 and 74 per cent respectively (P < 0·050). Inhibition of Rho kinase signalling significantly decreased radiation-provoked formation of CXC chemokines, MPO activity by 52 per cent, and intestinal leakage by 67 per cent (P < 0·050). CONCLUSION:: Rho kinase activity constitutes an important signalling mechanism in radiation-induced inflammation and intestinal barrier dysfunction. Copyright © 2010 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd.
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