| 1. |
- Westas, Emma, 1982, et al.
(författare)
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Biofilm formation on nanostructured hydroxyapatite-coated titanium
- 2014
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Ingår i: Journal of Biomedical Materials Research - Part A. - : Wiley. - 1552-4965 .- 1549-3296. ; 102:4, s. 1063-1070
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Tidskriftsartikel (refereegranskat)abstract
- Biofilm formation on medical devices is a common cause of implant failure, especially regarding implants that breach the epithelial tissue, so-called transcutaneous implants. Nanotechnology and the development of new nanomaterials have given the opportunity to design nanotextured implant surfaces. Such surfaces have been studied using various in vitro methods showing that nanosized features strongly benefit bone cell growth. However, little is known on how nanostructured features affect biofilm formation. The aim of this study was therefore to examine the shape- and chemical-dependent effect of a nanostructured hydroxyapatite (HA) coating on the degree of Staphylococcus epidermidis biofilm formation. Three different types of nanosized HA particles having different shapes and calcium to phosphate ratios were compared to uncoated turned titanium using safranin stain in a biofilm assay and confocal laser scanning microscopy (CLSM) for assessment of biofilm biomass and bacterial volume, respectively. No difference in biofilm biomass was detected for the various surfaces after 6 h incubation with S. epidermidis. Additionally, image analysis of CLSM Z-stacks confirmed the biofilm assay and showed similar results. In conclusion, the difference in nanomorphology and chemical composition of the surface coatings did not influence the adhesion and biofilm formation of S. epidermidis.
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| 2. |
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| 3. |
- Peruzzi, Niccolò, et al.
(författare)
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Multimodal ex vivo methods reveal that Gd-rich corrosion byproducts remain at the implant site of biodegradable Mg-Gd screws
- 2021
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Ingår i: Acta Biomaterialia. - : Elsevier. - 1742-7061 .- 1878-7568. ; 136, s. 582-591
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Tidskriftsartikel (refereegranskat)abstract
- Extensive research is being conducted on magnesium (Mg) alloys for bone implant manufacturing, due to their biocompatibility, biodegradability and mechanical properties. Gadolinium (Gd) is among the most promising alloying elements for property control in Mg alloy implants; however, its toxicity is controversial. Investigating Gd behavior during implant corrosion is thus of utmost importance. In this study, we analyzed the degradation byproducts at the implant site of biodegradable Mg-5Gd and Mg-10Gd implants after 12 weeks healing time, using a combination of different imaging techniques: histology, energy-dispersive x-ray spectroscopy (EDX), x-ray microcomputed tomography (µCT) and neutron µCT. The main finding has been that, at the healing time in exam, the corrosion appears to have involved only the Mg component, which has been substituted by calcium and phosphorus, while the Gd remains localized at the implant site. This was observed in 2D by means of EDX maps and extended to 3D with a novel application of neutron tomography. X-ray fluorescence analysis of the main excretory organs also did not reveal any measurable accumulation of Gd, further reinforcing the conclusion that very limited or no removal at all of Gd-alloy happened during degradation.
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| 4. |
- Falkman, Göran, 1968-, et al.
(författare)
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SOMWeb - Towards an Infrastructure for Knowledge Sharing in Oral Medicine
- 2005
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Ingår i: Connecting Medical Informatics and Bio-Informatics: Proceedings of MIE2005 - The XIXth International Congress of the European Federation for Medical Informatics. - Amsterdam : IOS Press. - 1586035495 ; 116, s. 527-32, s. 527-532
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Konferensbidrag (refereegranskat)abstract
- In a net-based society, clinicians can come together for cooperative work and distance learning around a common medical material. This requires suitable techniques for cooperative knowledge management and user interfaces that are adapted to both the group as a whole and to individuals. To support distributed management and sharing of clinical knowledge, we propose the development of an intelligent web community for clinicians within oral medicine. This virtual meeting place will support the ongoing work on developing a digital knowledge base, providing a foundation for a more evidence-based oral medicine. The presented system is founded on the use and development of web services and standards for knowledge modelling and knowledge-based systems. The work is conducted within the frame of a well-established cooperation between oral medicine and computer science.
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| 5. |
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| 6. |
- Leander, Jacob, 1987, et al.
(författare)
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A stochastic mixed effects model to assess treatment effects and fluctuations in home-measured peak expiratory flow and the association with exacerbation risk in asthma
- 2022
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Ingår i: Cpt-Pharmacometrics & Systems Pharmacology. - : Wiley. - 2163-8306. ; 11:2, s. 212-224
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Tidskriftsartikel (refereegranskat)abstract
- Home-based measures of lung function, inflammation, symptoms, and medication use are frequently collected in respiratory clinical trials. However, new statistical approaches are needed to make better use of the information contained in these data-rich variables. In this work, we use data from two phase III asthma clinical trials demonstrating the benefit of benralizumab treatment to develop a novel longitudinal mixed effects model of peak expiratory flow (PEF), a lung function measure easily captured at home using a hand-held device. The model is based on an extension of the mixed effects modeling framework to incorporate stochastic differential equations and allows for quantification of several statistical properties of a patient's PEF data: the longitudinal trend, long-term fluctuations, and day-to-day variability. These properties are compared between treatment groups and related to a patient's exacerbation risk using a repeated time-to-event model. The mixed effects model adequately described the observed data from the two clinical trials, and model parameters were accurately estimated. Benralizumab treatment was shown to improve a patient's average PEF level and reduce long-term fluctuations. Both of these effects were shown to be associated with a lower exacerbation risk. The day-to-day variability was neither significantly affected by treatment nor associated with exacerbation risk. Our work shows the potential of a stochastic model-based analysis of home-based lung function measures to support better estimation and understanding of treatment effects and disease stability. The proposed analysis can serve as a complement to descriptive statistics of home-based measures in the reporting of respiratory clinical trials.
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| 7. |
- Dorkhan, Marjan, et al.
(författare)
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Crystalline anatase-rich titanium can reduce adherence of oral streptococci
- 2014
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Ingår i: Biofouling (Print). - : Informa UK Limited. - 0892-7014 .- 1029-2454. ; 30:6, s. 751-759
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Tidskriftsartikel (refereegranskat)abstract
- Dental implant abutments that emerge through the mucosa are rapidly covered with a salivary protein pellicle to which bacteria bind, initiating biofilm formation. In this study, adherence of early colonizing streptococci, Streptococcus gordonii, Streptococcus oralis, Streptococcus mitis and Streptococcus sanguinis to two saliva-coated anodically oxidized surfaces was compared with that on commercially pure titanium (CpTi). Near edge X-ray absorption (NEXAFS) showed crystalline anatase was more pronounced on the anodically oxidized surfaces than on the CpTi. As revealed by fluorescence microscopy, a four-species mixture, as well as individual bacterial species, exhibited lower adherence after 2 h to the saliva-coated, anatase-rich surfaces than to CpTi. Since wettability did not differ between the saliva-coated surfaces, differences in the concentration and/or configuration of salivary proteins on the anatase-rich surfaces may explain the reduced bacterial binding effect. Anatase-rich surfaces could thus contribute to reduced overall biofilm formation on dental implant abutments through diminished adherence of early colonizers.
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| 8. |
- Elzinga, Aant, 1937
(författare)
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Andra forskningsvillkor skapade dåtidens nobelpristagare
- 2006
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Ingår i: Teori och praktik. En tidskrift från Malmös högskola. ; :04/2006, s. 34-41
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Vilka förutsättningar krävs för en kreativ forskning som leder fram till Nobelpris. Artikeln är tillkommen i en aktuell debatt efter Folkpartiets utspel i valrörelsen om att odla fram nya nobelpristagare vid svenska universitet i framtiden. Artikeln ger ett kritiskt perspektiv med historiska exempel som visar att utspelet var naiv och att helt andra förutsättningar än de som finns nu vid våra universitet krävs för att Sverige ska ta hem fler Nobelpris i framtiden.
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| 9. |
- Johansson, Carina B., 1955, et al.
(författare)
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Enhanced implant integration with hierarchically structured implants: a pilot study in rabbits
- 2012
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Ingår i: Clinical Oral Implants Research. - : Wiley. - 1600-0501 .- 0905-7161. ; 23:8, s. 943-953
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Tidskriftsartikel (refereegranskat)abstract
- Aim: To investigate bone-to-implant bonding for some novel surface modifications with a hierarchic structure and to correlate the in vivo results with surface roughness parameters. Materials and methods: Newly developed implants surfaces were tested in rabbits and compared with the commercially available OsseoSpeed™ (OS) implant. The blasted test samples were subjected to treatment in oxalic acid (AT-II), followed by subsequent etching in hydrofluoric acid (AT-I). Scanning electron microscopy and X-ray photoelectron spectroscopy were used to characterize the surface topography and chemical composition of the implants. Biomechanical testing after 6 weeks of healing was complemented with the quantification of fluorochromes and the results were subjected to a multivariate statistical analysis. Results: The results show, both with biomechanical- and with histomorphometrical tests, that the AT-I implants with different surface roughness at the micro (blasting), submicro (shallow cavities) and nanolevels (precipitates) have a greater bone tissue integration compared with the AT-II- and OS implants. The 2D bone-to-implant contact (BIC) data were in accordance with the 3D removal torque (RTQ) results even if the former were deduced from implants located in spongeous-type bone and the latter in cortical bone. The increase in RTQ values for the test samples AT-I and AT-II compared with the reference complies with the slightly higher Sa values for these surfaces. Conclusions: Using a combination of conventional methods with novel quantification of florochrome and multivariate analysis, the influence of surface roughness on different levels could be discriminated. The RTQ and BIC values show that the most hierarchical structure with submicro cavities and nanoscale precipitates possesses the most favourable osseointegration properties.
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| 10. |
- Sabel, Nina, 1973, et al.
(författare)
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XRMA analysis and X-ray diffraction analysis of dental enamel from human permanent teeth exposed to hydrogen peroxide of varying pH
- 2019
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Ingår i: Journal of Clinical and Experimental Dentistry. - : Medicina Oral, S.L.. - 1989-5488. ; 11:6, s. e512-e520
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Tidskriftsartikel (refereegranskat)abstract
- Background : This in vitro investigation shows how 3.3% H2O2, at different pH-values affects the enamel. Material and Methods : A number of fifteen human premolars were used. The enamel of the coronal half in six of the teeth, were exposed by H2O2. Nine teeth were prepared to enamel powder. The enamel was exposed to 3.3% H2O2, at six different pH-values (pH range 4.5 - 7.0). Analyses of the topography of enamel performed by scanning electron microscope (SEM) and the chemical composition of enamel by X-ray microanalysis (XRMA). X-ray powder diffraction (XRD) analysed the crystallinity in enamel powder. Results : The exposure to H2O2 at pH < 5.5 resulted in a rougher topography of the enamel, according to the SEM studies. The XRMA analysis revealed a increase in the ratio of Ca:C. Exposure to H2O2 at pH > 5.5 resulted in a decrease of O in the exposed enamel, and changes in C:P, Ca:C, Ca:P and Ca:O were observed. The H2O22 did not affect the unit cell parameters, but the signal-to-noise level was increased for slightly acidic or neutral solutions. The unit cell parameters decreased in the acidic solutions. Conclusions : The exposure to H2O2 at varying pH values affect the enamel with two different mechanisms. One effect is the oxidation of the organic or bioorganic matter in the hydroxyapatite matrix, due to the use of 3.3% H2O2. The other effect is due to the current pH of the H2O2, since the structure of the hydroxyapatite starts to erode when the pH < 5.5.
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