| 1. |
- Calon, Tim G A, et al.
(författare)
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Minimally Invasive Ponto Surgery compared to the linear incision technique without soft tissue reduction for bone conduction hearing implants: study protocol for a randomized controlled trial.
- 2016
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Ingår i: Trials. - : Springer Science and Business Media LLC. - 1745-6215. ; 17:1
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Tidskriftsartikel (refereegranskat)abstract
- Over the last years, less invasive surgical techniques with soft tissue preservation for bone conduction hearing implants (BCHI) have been introduced such as the linear incision technique combined with a punch. Results using this technique seem favorable in terms of rate of peri-abutment dermatitis (PAD), esthetics, and preservation of skin sensibility. Recently, a new standardized surgical technique for BCHI placement, the Minimally Invasive Ponto Surgery (MIPS) technique has been developed by Oticon Medical AB (Askim, Sweden). This technique aims to standardize surgery by using a novel surgical instrumentation kit and minimize soft tissue trauma.A multicenter randomized controlled trial is designed to compare the MIPS technique to the linear incision technique with soft tissue preservation. The primary investigation center is Maastricht University Medical Center. Sixty-two participants will be included with a 2-year follow-up period. Parameters are introduced to quantify factors such as loss of skin sensibility, dehiscence of the skin next to the abutment, skin overgrowth, and cosmetic results. A new type of sampling method is incorporated to aid in the estimation of complications. To gain further understanding of PAD, swabs and skin biopsies are collected during follow-up visits for evaluation of the bacterial profile and inflammatory cytokine expression. The primary objective of the study is to compare the incidence of PAD during the first 3 months after BCHI placement. Secondary objectives include the assessment of parameters related to surgery, wound healing, pain, loss of sensibility of the skin around the implant, implant extrusion rate, implant stability measurements, dehiscence of the skin next to the abutment, and esthetic appeal. Tertiary objectives include assessment of other factors related to PAD and a health economic evaluation.This is the first trial to compare the recently developed MIPS technique to the linear incision technique with soft tissue preservation for BCHI surgery. Newly introduced parameters and sampling method will aid in the prediction of results and complications after BCHI placement.Registered at the CCMO register in the Netherlands on 24 November 2014: NL50072.068.14 . Retrospectively registered on 21 April 2015 at ClinicalTrials.gov: NCT02438618 . This trial is sponsored by Oticon Medical AB.
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| 2. |
- Johansson, Martin L, et al.
(författare)
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Non-invasive sampling procedure revealing the molecular events at different abutments of bone-anchored hearing systems–A prospective clinical pilot study
- 2022
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Ingår i: Frontiers in Neuroscience. - : Frontiers Media SA. - 1662-4548 .- 1662-453X. ; 16
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To investigate the molecular activities in different compartments around the bone-anchored hearing system (BAHS) with either electropolished or machined abutments and to correlate these activities with clinical and microbiological findings. Materials and methods: Twelve patients received machined or electropolished abutments after implant installation of BAHS. Peri-abutment fluid and tissue were collected from baseline to 12 months. Gene expression of cytokines and factors related to tissue healing and inflammation, regeneration and remodelling, as well as bacterial recognition were determined using quantitative-polymerase chain reaction (qPCR). The clinical status was evaluated using the Holgers scoring system, and bacterial colonisation was investigated by culturing. Results: The gene expression of inflammatory cytokines (IL-8, IL-1β, and IL-10) and bacteria-related Toll-like receptors (2 and 4) was higher in the peri-abutment fluid than at baseline and in the peri-abutment tissue at 3 and 12 months. Conversely, the expression of genes related to tissue regeneration (Coll1a1 and FOXO1) was higher in the tissue samples than in the peri-abutment fluid at 3 and 12 months. Electropolished abutments triggered higher expression of inflammatory cytokines (IL-8 and IL-1β) (in peri-abutment fluid) and regeneration factor FOXO1 (in peri-abutment tissue) than machined abutments. Several cytokine genes in the peri-abutment fluid correlated positively with the detection of aerobes, anaerobes and Staphylococcus species, as well as with high Holger scores. Conclusion: This study provides unprecedented molecular information on the biological processes of BAHS. Despite being apparently healed, the peri-abutment fluid harbours prolonged inflammatory activity in conjunction with the presence of different bacterial species. An electropolished abutment surface appears to be associated with stronger proinflammatory activity than that with a machined surface. The analysis of the peri-abutment fluid deserves further verification as a non-invasive sampling and diagnostic procedure of BAHS.
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| 3. |
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| 4. |
- Johansson, Martin L, et al.
(författare)
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The microbiological profile of the bone-anchored hearing system.
- 2019
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Ingår i: 7th International Symposium on Bone Conduction Hearing and Related Technologies (OSSEO), At Miami beach, FL, USA.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Purpose The aim of this study was to evaluate methods for bacterial sampling and to acquire insight into the role of the microbiota on the clinical outcome of BAHS. Methods and Materials For the identification and quantification of colonising bacteria, 3 sampling techniques from 3 different compartments were evaluated: (i) retrieval of abutments, (ii) sampling of the peri-abutment exudate using paper-points and, (iii) sampling of the peri-abutment soft tissue using a biopsy punch. Results Quantification of viable bacteria was possible from all three compartments. At baseline the soft tissue was mainly colonised by anaerobic bacteria. Anaerobic bacteria and Staphylococcus spp. were subsequently detected in all three compartments at 3 and 12 months. During the one-year follow-up, the common skin coloniser Staphylococcus epidermidis was present at the implant site in most patients whereas Staphylococcus aureus was present in half of the patients. Several associations between clinical and microbiological parameters were found. Conclusion This study confirmed a suitable study design, sampling and analytical methodology to quantitate, describe and isolate the bacterial species associated to BAHS. Characterising the microbiota present at different sites surrounding BAHS as well as elucidating their associations with clinical parameters and host response markers may have relevance for the outcome following implantation.
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| 5. |
- Jonhede, Sofia, et al.
(författare)
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Acute effects of the sigma-2 receptor agonist siramesine on lysosomal and extra-lysosomal proteolytic systems in lens epithelial cells
- 2010
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Ingår i: Molecular Vision. - 1090-0535. ; 16, s. 819-827
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The aim of the present study was to examine the effects of the sigma-2 receptor agonist, siramesine, on morphology, growth, cell death, lysosomal function, and effects on extra-lysosomal proteolytic systems in human lens epithelial cells. Methods: Human lens epithelial cells in culture were exposed to siramesine and examined for morphological changes using Nomarski optics or calcein. Lysosomes were evaluated using acridine orange and Magic Red (RR-cresyl violet). Nuclear morphology was studied using Hoechst 33342 and propidium iodide. Enzymatic activities in living cells or cell lysates were studied using fluorogenic substrates. Results: Siramesine at low concentrations increased the cytoplasmic proteolytic activity of the proteasome and the calpain system. Effects were also observed with respect to lysosomal morphology, acidity and function. In addition, activation of caspase-3 and the appearance of nuclei with an apoptotic morphology was found. Conclusions: Siramesine at low concentrations affects lens epithelial cells with perturbations of the major proteolytic systems and lysosomal morphology, resulting in caspase activation and cell death. Siramesine may be a possible substance for the treatment or prevention of posterior capsular opacification (PCO).
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| 6. |
- Karlsson, Jan-Olof, 1944, et al.
(författare)
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Acute Effects of the Sigma-2 Receptor Agonist Siramesine on Lens Epithelial Cells
- 2007
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Ingår i: Invest. Ophthalmol. Vis. Sci.. ; 48:5, s. 2432-
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Konferensbidrag (refereegranskat)abstract
- PurposeExperiments were carried out to study the effects of siramesine on markers for apoptosis, oxidative damage and mitochondrial function in primary cultures of human lens epithelial cells (HLEC). MethodsHLEC were incubated with 25 {micro}M siramesine for 1, 2, 3, 4, 6 and 8 hours. Caspase-3 was assayed in cell extracts with DEVD-AMC. Mitochondrial depolarization was assayed with JC-1. Peroxide production was studied with DCF-DA and superoxide levels with hydroethidium. Glutathione levels were assayed with monochlorobimane. ResultsSiramesine induced a significant increase of caspase-3 activity after 6h exposure to 25 {micro}M siramesine. Nuclear morphology examined with Hoechst 33342 showed signs of apoptosis after the same time intervals. A significant increase in the production of peroxide and superoxide were found up to 4 -8 hours after administration of siramesine. ConclusionsSiramesine, a piperidine analogue, was developed for the treatment of psychiatic disorders and is considered to be relatively nontoxic. This study, and others, indicate effects on cell growth, apoptosis and production of ROS. The sigma-2 receptor may be a regulator of HLEC growth and apoptosis.
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| 7. |
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| 8. |
- Karlsson, Jan-Olof, 1944, et al.
(författare)
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Sigma-2 receptor agonists kill lens epithelial cells
- 2010
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Ingår i: Acta Ophthalmologica. 2010;88:S246. Presented at European Vision and Eye Research (EVER) Annual Meeting 2010, 6-9 Oct, Crete, Greece.. - : Wiley.
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Konferensbidrag (refereegranskat)
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| 9. |
- Petersen, Anne, 1962, et al.
(författare)
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Effects of dexamethasone on human lens epithelial cells in culture
- 2008
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Ingår i: Mol Vis. - 1090-0535. ; 14, s. 1344-52
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: Treatment with glucocorticoids is a well known risk factor for cataract development, although the pathogenic mechanism has not been elucidated. The aim of the study was to investigate the effects of glucocorticoids in cultured human lens epithelial cells. METHODS: Human lens epithelial cells (HLECs) were exposed to dexamethasone for 24 h. The number of viable cells was determined using the 3-[4, 5-dimethylthiazolyl-2]-2, 5-diphenyltetrazolium bromide (MTT) assay, and proliferation was quantified using Ki-67. Apoptosis was investigated by measuring caspase-3 activity and by evaluating nuclear morphology of cells stained with Hoechst 33342. Mitochondria depolarization was measured using the potential-sensitive color, JC-1. Cells were assayed for changes in superoxide production using dihydroethidium (HET), for alterations in peroxide production using dichlorofluorescein diacetate (DCFH-DA), and for glutathione (GSH) variations using monochlorobimane (MCB). Caspase-3 activity was also measured in HLECs simultaneously exposed to dexamethasone and the glucocorticoid antagonist, RU486. RESULTS: Low doses of dexamethasone (0.1 microM) resulted in increased proliferation of HLECs. Apoptosis was increased in HLECs exposed to 1 microM, 10 microM, and 100 microM of dexamethasone as revealed by nuclear morphology studies. Apoptosis was also confirmed by measuring caspase-3 activation. No effect on superoxide production by dexamethasone was seen. There were no effects on GSH levels or mitochondrial depolarization either. Only the highest concentration of dexamethasone (100 microM) caused an increase in peroxide production. In HLECs incubated with the glucocorticoid antagonist, RU486, apoptosis was induced at a lower concentration of dexamethasone (0.1 microM) than with dexamethasone alone. CONCLUSIONS: Low doses of dexamethasone cause a moderate increase in proliferation of cultured HLECs. Slightly higher but still physiologically relevant concentrations of dexamethasone result in a dose-dependent increase in apoptosis. Dexamethasone-induced apoptosis in HLECs does not seem to involve oxidative mechanisms. The proapoptotic effect of dexamethasone does not appear to act through the glucocorticoid receptor. Effects on proliferation and/or dysregulation of apoptosis in lens epithelial cells may be an important factor in human steroid-induced posterior subcapsular cataract.
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| 10. |
- Strijbos, Ruben M., et al.
(författare)
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Long-Term Outcomes of the Minimally Invasive Ponto Surgery vs. Linear Incision Technique With Soft Tissue Preservation for Installation of Percutaneous Bone Conduction Devices
- 2021
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Ingår i: Frontiers in Neurology. - : Frontiers Media SA. - 1664-2295. ; 12:112
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Comparing the surgical outcomes of the Minimally Invasive Ponto Surgery (MIPS) technique with the linear incision technique with soft tissue preservation (LITT-P) for bone conduction devices after a follow-up of 22 months. Methods: In this multicenter randomized controlled trial, there was the inclusion of 64 adult patients eligible for unilateral surgery. There was 1:1 randomization to the MIPS (test) or the LITT-P (control) group. The primary outcome was an (adverse) soft tissue reaction. Secondary outcomes were pain, loss of sensibility, soft tissue height/overgrowth, skin sagging, implant loss, Implant Stability Quotient measurements, cosmetic scores, and quality of life questionnaires. Results: Sixty-three subjects were analyzed in the intention-to-treat population. No differences were found in the presence of (adverse) soft tissue reactions during complete follow-up. Also, there were no differences in pain, wound dehiscence, skin level, soft tissue overgrowth, and overall quality of life. Loss of sensibility (until 3-month post-surgery), cosmetic scores, and skin sagging outcomes were better in the MIPS group. The Implant Stability Quotient was higher after the LITT-P for different abutment lengths at various points of follow-up. Implant extrusion was nonsignificantly higher after the MIPS (15.2%) compared with LITT-P (3.3%). Conclusion: The long-term results show favorable outcomes for both techniques. The MIPS is a promising technique with some benefits over the LITT-P. Concerns regarding nonsignificantly higher implant loss may be overcome with future developments and research. Clinical Trial Registration: www.ClinicalTrials.gov, identifier: NCT02438618.
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