| 1. |
- Thomas, HS, et al.
(författare)
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- 2019
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swepub:Mat__t
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| 2. |
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| 3. |
- Ademuyiwa, Adesoji O., et al.
(författare)
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Determinants of morbidity and mortality following emergency abdominal surgery in children in low-income and middle-income countries
- 2016
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Ingår i: BMJ Global Health. - : BMJ Publishing Group Ltd. - 2059-7908. ; 1:4
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Tidskriftsartikel (refereegranskat)abstract
- Background: Child health is a key priority on the global health agenda, yet the provision of essential and emergency surgery in children is patchy in resource-poor regions. This study was aimed to determine the mortality risk for emergency abdominal paediatric surgery in low-income countries globally.Methods: Multicentre, international, prospective, cohort study. Self-selected surgical units performing emergency abdominal surgery submitted prespecified data for consecutive children aged <16 years during a 2-week period between July and December 2014. The United Nation's Human Development Index (HDI) was used to stratify countries. The main outcome measure was 30-day postoperative mortality, analysed by multilevel logistic regression.Results: This study included 1409 patients from 253 centres in 43 countries; 282 children were under 2 years of age. Among them, 265 (18.8%) were from low-HDI, 450 (31.9%) from middle-HDI and 694 (49.3%) from high-HDI countries. The most common operations performed were appendectomy, small bowel resection, pyloromyotomy and correction of intussusception. After adjustment for patient and hospital risk factors, child mortality at 30 days was significantly higher in low-HDI (adjusted OR 7.14 (95% CI 2.52 to 20.23), p<0.001) and middle-HDI (4.42 (1.44 to 13.56), p=0.009) countries compared with high-HDI countries, translating to 40 excess deaths per 1000 procedures performed.Conclusions: Adjusted mortality in children following emergency abdominal surgery may be as high as 7 times greater in low-HDI and middle-HDI countries compared with high-HDI countries. Effective provision of emergency essential surgery should be a key priority for global child health agendas.
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| 4. |
- Micheletti, Chiara, et al.
(författare)
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Bone mineral organization at the mesoscale: A review of mineral ellipsoids in bone and at bone interfaces
- 2022
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Ingår i: Acta Biomaterialia. - : Elsevier BV. - 1742-7061. ; 142, s. 1-13
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Tidskriftsartikel (refereegranskat)abstract
- Much debate still revolves around bone architecture, especially at the nano- and microscale. Bone is a remarkable material where high strength and toughness coexist thanks to an optimized composition of mineral and protein and their hierarchical organization across several distinct length scales. At the nanoscale, mineralized collagen fibrils act as building block units. Despite their key role in biological and mechanical functions, the mechanisms of collagen mineralization and the precise arrangement of the organic and inorganic constituents in the fibrils remains not fully elucidated. Advances in three-dimensional (3D) characterization of mineralized bone tissue by focused ion beam-scanning electron microscopy (FIB-SEM) revealed mineral-rich regions geometrically approximated as prolate ellipsoids, much larger than single collagen fibrils. These structures have yet to become prominently recognized, studied, or adopted into biomechanical models of bone. However, they closely resemble the circular to elliptical features previously identified by scanning transmission electron microscopy (STEM) in two-dimensions (2D). Herein, we review the presence of mineral ellipsoids in bone as observed with electron-based imaging techniques in both 2D and 3D with particular focus on different species, anatomical locations, and in proximity to natural and synthetic biomaterial interfaces. This review reveals that mineral ellipsoids are a ubiquitous structure in all the bones and bone-implant interfaces analyzed. This largely overlooked hierarchical level is expected to bring different perspectives to our understanding of bone mineralization and mechanical properties, in turn shedding light on structure-function relationships in bone. Statement of significance: In bone, the hierarchical organization of organic (mainly collagen type I) and inorganic (calcium-phosphate mineral) components across several length scales contributes to a unique combination of strength and toughness. However, aspects related to the collagen-mineral organization and to mineralization mechanisms remain unclear. Here, we review the presence of mineral prolate ellipsoids across a variety of species, anatomical locations, and interfaces, both natural and with synthetic biomaterials. These mineral ellipsoids represent a largely unstudied feature in the organization of bone at the mesoscale, i.e., at a level connecting nano- and microscale. Thorough understanding of their origin, development, and structure can provide valuable insights into bone architecture and mineralization, assisting the treatment of bone diseases and the design of bio-inspired materials. © 2022 Acta Materialia Inc.
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| 5. |
- Johansson, Martin L, et al.
(författare)
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Multimodal Analysis of the Tissue Response to a Bone-Anchored Hearing Implant: Presentation of a Two-Year Case Report of a Patient With Recurrent Pain, Inflammation, and Infection, Including a Systematic Literature Review.
- 2021
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Ingår i: Frontiers in cellular and infection microbiology. - : Frontiers Media SA. - 2235-2988. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Osseointegration is a well-established concept used in applications including the percutaneous Bone-Anchored Hearing System (BAHS) and auricular rehabilitation. To date, few retrieved implants have been described. A systematic review including cases where percutaneous bone-anchored implants inserted in the temporal bone were retrieved and analyzed was performed. We also present the case of a patient who received a BAHS for mixed hearing loss. After the initial surgery, several episodes of soft tissue inflammation accompanied by pain were observed, leading to elective abutment removal 14 months post-surgery. Two years post-implantation, the implant was removed due to pain and subjected to a multiscale and multimodal analysis: microbial DNA using molecular fingerprinting, gene expression using quantitative real-time polymerase chain reaction (qPCR), X-ray microcomputed tomography (micro-CT), histology, histomorphometry, backscattered scanning electron microscopy (BSE-SEM), Raman spectroscopy, and fluorescence in situ hybridization (FISH). Evidence of osseointegration was provided via micro-CT, histology, BSE-SEM, and Raman spectroscopy. Polymicrobial colonization in the periabutment area and on the implant, including that with Staphylococcus aureus and Staphylococcus epidermidis, was determined using a molecular analysis via a 16S-23S rDNA interspace [IS]-region-based profiling method (IS-Pro). The histology suggested bacterial colonization in the skin and in the peri-implant bone. FISH confirmed the localization of S. aureus and coagulase-negative staphylococci in the skin. Ten articles (54 implants, 47 patients) met the inclusion criteria for the literature search. The analyzed samples were either BAHS (35 implants) or bone-anchored aural epitheses (19 implants) in situ between 2 weeks and 8 years. The main reasons for elective removal were nonuse/changes in treatment, pain, or skin reactions. Most samples were evaluated using histology, demonstrating osseointegration, but with the absence of bone under the implants' proximal flange. Taken together, the literature and this case report show clear evidence of osseointegration, despite prominent complications. Nevertheless, despite implant osseointegration, chronic pain related to the BAHS may be associated with a chronic bacterial infection and raised inflammatory response in the absence of macroscopic signs of infection. It is suggested that a multimodal analysis of peri-implant health provides possibilities for device improvements and to guide diagnostic and therapeutic strategies to alleviate the impact of complications.
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| 6. |
- Micheletti, Chiara, et al.
(författare)
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Multimodal and Multiscale Characterization of the Bone-Bacteria Interface in a Case of Medication-Related Osteonecrosis of the Jaw
- 2022
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Ingår i: JBMR Plus. - : Wiley. - 2473-4039. ; 6:12
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Tidskriftsartikel (refereegranskat)abstract
- Medication-related osteonecrosis of the jaw (MRONJ) is a known side effect of bisphosphonates (BPs). Although bacterial infection is usually present, the etiology of MRONJ remains unknown. Here we apply a multimodal and multiscale (micro-to-nano) characterization approach to investigate the interface between necrotic bone and bacteria in MRONJ. A non-necrotic bone sample was used as control. Both necrotic and non-necrotic bone samples were collected from the jaw of a female individual affected by MRONJ after using BPs for 23 years. For the first time, resin cast etching was used to expose bacteria at the necrotic site. The bone-bacteria interface was also resolved at the nanoscale by scanning transmission electron microscopy (STEM). Nanosized particulates, likely corresponding to degraded bone mineral, were often noted in close proximity to or enclosed by the bacteria. STEM also revealed that the bone-bacteria interface is composed of a hypermineralized front fading into a highly disordered region, with decreasing content of calcium and phosphorus, as assessed by electron energy loss spectroscopy (EELS). This, combined with the variation in calcium, phosphorus, and carbon across the necrotic bone-bacteria interface evaluated by scanning electron microscopy (SEM)-energy dispersive X-ray spectroscopy (EDX) and the lower mineral-to-matrix ratio measured by micro-Raman spectroscopy in necrotic bone, indicates the absence of a mineralization front in MRONJ. It appears that the bone-bacteria interface originates not only from uncontrolled mineralization but also from the direct action of bacteria degrading the bone matrix. (c) 2022 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.
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| 7. |
- Shah, Furqan A., et al.
(författare)
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Influence of cell culture medium composition on in vitro dissolution behaviour of a fluoride-containing bioactive glass
- 2014
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Ingår i: Journal of Biomedical Materials Research. Part A. - : Wiley. - 1549-3296 .- 1552-4965. ; 102:3
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Tidskriftsartikel (refereegranskat)abstract
- SUMMARY: Bioactive glasses are used clinically for bone regeneration, and their bioactivity and cell compatibility are often characterised in vitro, using physiologically relevant test solutions. The aim of this study was to show the influence of varying medium characteristics (pH, composition, presence of proteins) on glass dissolution and apatite formation. The dissolution behaviour of a fluoride-containing bioactive glass was investigated over a period of one week in Eagle's Minimal Essential Medium with Earle's Salts (MEM), supplemented with either, (a) acetate buffer, (b) 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) buffer, (c) HEPES + carbonate or (d) HEPES + carbonate + foetal bovine serum. Results show pronounced differences in pH, ion release and apatite formation over 1 week: Despite its acidic pH (pH 5.8 after bioactive glass immersion, compared to pH 7.4 to 8.3 for HEPES-containing media), apatite formation was fastest in acetate buffered (HEPES-free) MEM. Presence of carbonate resulted in formation of calcite (calcium carbonate). Presence of serum proteins, on the other hand, delayed apatite formation significantly. These results confirm that the composition and properties of a tissue culture medium are important factors during in vitro experiments and need to be taken into consideration when interpreting results from dissolution or cell culture studies.
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| 8. |
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| 9. |
- Ben Amara, Heithem, 1984, et al.
(författare)
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Bone healing around biodegradable Magnesium implants: Differential response between interfacial and near-implant bone in vivo
- 2022
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Ingår i: 14th Symposium on Biodegradable Metals, Alicante, Spain 24-29 August 2022.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- INTRODUCTION: By virtue of their mechanical properties and of their degradation, magnesium (Mg)-based osteosynthesis systems are metallic implants that hold the fractured bones while eliminated in situ, thus offering the promise of reduced complications posed by permanent implants. A growing amount of research validated Mg-based implants for bone fixation by providing robust evidence in support of new bone deposition in contact with the interfacial degradation layer. Whereas Mg-degradation products are known to distribute in the implant environment, less attention has been paid to the bone response at distance from the implant interface. The present study investigated the structural, cellular, and molecular events taking place at the bone-Mg implant interface and at distance from it after in vivo implantation in an experimental rat model. METHODS: Following approval by the Local Ethical Committee at the University of Gothenburg (Dnr: 14790/2019), male Sprague-Dawley rats (n=56) were implanted with miniature screws manufactured from pure magnesium (99.99% - high purity; Mg) or from pure titanium (grade 4; Ti) (herein, serving as a control, enabling osseointegration in this model). In each animal, the metaphysis of the left and right tibiae was drilled prior to the insertion of Ti or Mg screws. After 3 and 28 days, animals were euthanized, and two types of samples were retrieved (Fig. 1): 1-Implants and peri-implant bone for quantitative polymerase chain reaction (qPCR) (n=8/group/time-point): were separately collected and allocated for molecular gene expression of the implant-adherent cells and of the cells in the peri-implant space. 2-Peri-implant bone with implants en bloc for paraffin or plastic embedding (n=6/group/time-point): enabling radiographical analyses using micro-computed tomography (micro-CT) and histomorphometrical measurements of the bone at the implant interface and at distance from it. Statistical comparisons were made between experimental groups at each time point and between time-points for each experimental group. (Kruskal-Wallis, Mann-Whitney and Wilcoxon signed-rank tests; p<0.05). RESULTS: While histological observations provided evidence of new bone formation at the vicinity of both Ti and Mg, the bone marrow at distance from the implant-interface featured morphological differences between groups (Fig. 2). At 3 days, the proportion of the interstitial and microvascular area was significantly higher at the expense of the area occupied by the hematopoietic cells in Mg- vs Ti-implanted metaphyses. At 28 days, bone marrow around Mg implants showed significantly higher adiposity in comparison to Ti implants. Yet, no differences in the trabecular bone micro-architecture were detected between biomaterials by micro-CT analysis at distance from the implant-interface. The RNA extracted from cells from the implant surface and from the peri-implant bone revealed good quality, allowing detailed molecular analysis. CONCLUSIONS: In comparison to non-degradable Ti controls, the degradation of Mg implants changes the composition of the peri-implant bone marrow, but yet without alteration of new bone formation at the implant interface. ACKNOWLEDGEMENTS: Mg rods were generously provided by the Helmholtz-Zentrum Hereon, Geesthacht, Germany. This project is part of the European Training Network within the framework of Horizon 2020 Marie Skłodowska-Curie Action No 811226.
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| 10. |
- Ben Amara, Heithem, 1984, et al.
(författare)
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Dissecting the sequential interaction between biodegradable magnesium implants and soft tissues in vivo
- 2022
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Ingår i: Materials Science and Engineering Congress, Dredsen, Germany, 27-29 September 2022.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Magnesium-based biomaterials are developed with the intention to enable tissue regeneration while being degraded under physiological conditions and eventually eliminated from the body. Once in contact with tissues, the biodegradability and the biocompatibility of magnesium implants (Mg) are governed by the direct interactions with their immediate milieu. The precise mechanisms through which the soft tissue micro-environment shapes the behaviour of Mg and the host-response remain elusive. Here, it is demonstrated that Mg degradation modulates the initial acute immune response and the subsequent fibrous encapsulation upon subcutaneous implantation in rats monitored at 1-, 3-, 6-, 14- and 28-days following surgery. In comparison to titanium implants (Ti), the initial profuse release of Mg degradation products activates pro-inflammatory pathways through increased recruitment of inflammatory cells to the soft tissue/implant interface and upregulation of pro-inflammatory genes, in parallel with a superior neo-angiogenesis and vascularization at Mg. After 6d, a shift in Mg degradation kinetics dissipates the initial pro-inflammatory response and facilitates the assembly of a comparatively thinner fibrous tissue capsule than around Ti. The reduction in the fibrous encapsulation around the Mg implant aligns with a superior expression of anti-fibrotic marker FOXO-1 at the tissue interface with Mg versus Ti. Mg induce an initial potent yet transient inflammatory response, which is associated with less adverse fibrous encapsulation after tissue healing. Tailoring Mg with controlled initial degradation appears to be crucial to enabling a successful coupling between inflammation and tissue repair during the early host response to Mg.
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