| 1. |
- Juhlin, Annika, et al.
(författare)
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Staphylococcal biofilm gene expression on biomaterials - A methodological study
- 2017
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Ingår i: Journal of Biomedical Materials Research Part A. - : Wiley. - 1549-3296. ; 105:12, s. 3400-3412
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Tidskriftsartikel (refereegranskat)abstract
- The combination of increased healthcare access, universal aging, and infallible therapy demands, synergistically drive the need for the development of biomaterial technologies that mitigate the challenge of biomaterial-associated infections (BAI). Staphylococcus epidermidis and Staphylococcus aureus account for the majority of BAI due to their ability to accumulate in adherent multilayered biofilm. This investigation details the development of gene expression assays to evaluate the genetic processes of attachment, accumulation, maturation, and dispersal phases of biofilms on biomaterials in vitro, while abiding by the Minimum Information for Publication of Quantitative Real-Time PCR Experiments (MIQE) guidelines. The biofilm formation of S. epidermidis on polyurethane (PU) central venous catheters and S. aureus on machined titanium (Ti) was examined in terms of gene expression at early and late time points. The results provided insight into how each stage of biofilm formation is orchestrated over time on these biomaterials in vitro. Furthermore, the results suggested that mechanical RNA extraction, organic solvents, elimination of genomic DNA, and preamplification are advisable strategies to implement for biofilm gene expression analysis. It is concluded that this method can be employed for the assessment of biofilm-biomaterial interactions at the molecular level. (c) 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 3400-3412, 2017.
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| 2. |
- Lennerås, Maria, 1980, et al.
(författare)
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The clinical, radiological, microbiological and molecular profile of the skin-penetration site of transfemoral amputees treated with bone-anchored prostheses.
- 2017
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Ingår i: Journal of Biomedical Materials Research. - : Wiley. - 0021-9304 .- 1097-4636 .- 1549-3296. ; 105:2
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Tidskriftsartikel (refereegranskat)abstract
- The breach of the skin barrier is a critical issue associated with the treatment of individuals with transfemoral amputation (TFA) using osseointegrated, percutaneous titanium implants. Thirty TFA patients scheduled for abutment exchange or removal were consecutively enrolled. The aims were to determine the macroscopic skin signs, the presence of bacteria and the gene expression in abutment-adherent cells and to conduct correlative and comparative analyses between the different parameters. Redness and a granulation ring were present in 47% of the patients. Bacteria were detected in 27/30 patients, commonly in the bone canal. Staphylococcus aureus, coagulase-negative staphylococci, streptococci, and Enterococcus faecalis were the most common. A positive correlation was found between TNF-α expression and the detection of S. aureus. Staphylococcus aureus together with other bacterial species revealed a positive relationship with MMP-8 expression. A negative correlation was demonstrated between the length of the residual femur bone and the detection of a granulation ring and E. faecalis. A positive correlation was revealed between fixture loosening and pain and the radiological detection of endosteal bone resorption. Fixture loosening was also correlated with the reduced expression of interleukin-10 and osteocalcin. It is concluded that several relationships exist between clinical, radiological, microbiological, and molecular assessments of the percutaneous area of TFAs. Further long term studies on larger patient cohorts are required to determine the precise cause-effect relationships and unravel the role of host-bacteria interactions in the skin, bone canal and on the abutment for the longevity of percutaneous implants as treatment of TFA. © 2016 Wiley Periodicals, Inc. J
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| 3. |
- Svensson, Sara, 1981, et al.
(författare)
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Site-specific gene expression analysis of implant-near cells in a soft tissue infection model - Application of laser microdissection to study biomaterial-associated infection
- 2017
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Ingår i: Journal of Biomedical Materials Research Part A. - : Wiley. - 1549-3296. ; 105:8, s. 2210-2217
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Tidskriftsartikel (refereegranskat)abstract
- Analysis of the implant-tissue interface is important for an understanding of the cellular response to biomaterials with different surface characteristics. However, inaccessibility to the site has restricted the detailed evaluation of the tissue surrounding the implant. Laser microdissection enables the isolation of specific cells and tissues for subsequent DNA, RNA, or protein analysis. The present experimental study employed laser microdissection to analyze tissue-specific differences in gene expression in cells around infected or control titanium implants 72 h after subcutaneous implantation in a rat model. Three different tissue zones located 0-800 mu m away from the implant-tissue interface were analyzed. Implant sites challenged with a dose of 10(6) CFU Staphylococcus epidermidis demonstrated higher gene expression of selected markers for inflammation (TNF-alpha, IL-6), cell recruitment (MCP-1, IL-8, IL-8 R), infection (TLR2), and tissue remodeling (MMP-9) compared with control implants. Furthermore, the gene expression analysis of the three extracted tissue zones revealed marked spatial differences, depending on the distance to the implant. Control implants continuously induced higher cell gene expression in the implant-tissue interface compared with cells 200-800 mu m away from the implant, whereas the sites inoculated with S. epidermidis resulted in high gene expression further away from the implant as well. In conclusion, this study demonstrates that laser microdissection is an interesting tool, revealing both gene-and site-specific gene expression patterns in the implant-tissue interface. The technique provides an opportunity for detailed molecular dissection of the biological events related to the implant but occurring at different distances from the implant. (C) 2017 Wiley Periodicals, Inc.
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