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| 2. |
- Biel, Anders, et al.
(författare)
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The use of MgO-paste as a biodegradeable bone cement
- 2016
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Ingår i: Materials Today. - : Elsevier. - 2214-7853. ; 3:2, s. 556-561
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Tidskriftsartikel (refereegranskat)abstract
- The use of MgO-paste as bone cement was tested on titanium cylinders implanted into rat tibia. The evaluation of bone healingwas made with the retention force (pull-out) test, light microscopy and ESEM/ EDX. Preimplantation of the MgO-paste into drillperforations of rat tibia increased the retention of the titanium implant 6-fold. The error was expressed as the 95% confidenceinterval of means (n=10 bones in each group). The observed difference between 3.46+/-0.71 N/mm2 for Ti-cylinders implantedwith MgO-paste and 0.56+/-0.26 N/mm2 for Ti-cylinders implanted directly into the bone, is statistically significant (p<0.01).The increase of retention force, caused by MgO is parallel to an increased thickness of the compact bone surrounding the implantand closer contact between bone and implant.Histological examination of the implant-related bone showed that the MgO-induced bone growth is mediated by the formation ofa bone-inducing matrix. The matrix contains organic substance, most likely proteins.
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| 3. |
- Börner, Katrin, 1979, et al.
(författare)
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Distribution of cholesterol and galactosylceramide in rat cerebellar white matter.
- 2006
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Ingår i: Biochimica et biophysica acta. - : Elsevier BV. - 0006-3002. ; 1761:3, s. 335-44
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Tidskriftsartikel (refereegranskat)abstract
- White matter and the inner granular layer of rat cerebellum was analysed by imaging time-of-flight secondary-ion mass spectrometry (TOF-SIMS) equipped with a Bi+ ion cluster gun. Samples were prepared by high pressure freezing, freeze-fracturing and freeze drying or by plunge freezing and cryostat sectioning. The identified and localized chemical species were: sodium, potassium, phosphocholine, cholesterol and galactosylceramide (GalC) with carbon chain lengths C18:0 (N-stearoyl-galactosylceramide) and C24:0 (N-lignoceroylgalactosylceramide) with CH24:0 (hydroxy-lignoceroylgalactosylceramide). We report new findings regarding the organization of myelin in white matter. One is cholesterol-rich, ribbon-shaped 10-20 microm areas excluding Na+ and K+. The second finding is the different distribution of GalC C18 and GalC C24 in relation to these areas, where GalC C18 was localized in cholesterol-rich areas and GalC C24 was localized in Na/K-enriched areas. The distribution of GalC was in small spots, homogeneous in size, of 0.8-1.5 microm. Sample preparation with high pressure freezing allowed separate localization of sodium and potassium in tissue samples.
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| 4. |
- Börner, Katrin, 1979, et al.
(författare)
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Localization of Na+ and K+ in rat cerebellum with imaging TOF-SIMS
- 2006
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Ingår i: Applied Surface Science. - : Elsevier BV. - 0169-4332. ; 252:19, s. 6777-6781
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Tidskriftsartikel (refereegranskat)abstract
- High pressure-frozen (HPF), freeze-fractured and freeze-dried rat cerebellum was analyzed with imaging TOF-SIMS equipped with a Bi-cluster ion source. Data were collected separately as spectra of high mass resolution m/Δm > 8000 and images of high lateral resolution <700 nm. Images were made showing the localization of the peaks m/z = 22.99, and m/z = 39.1. Topographical effects were noted due to the freeze fracture method. This effect was compensated by normalizing images of specific secondary ions to the intensity of total secondary ions and by making PCA analysis of the image. The results showed that potassium ions were localized in blood vessels and cortex cells and sodium ions were localized in blood vessels and cerebellar interstitial tissue and in the nuclei of some cells. The sodium ion concentration was found to be higher in blood vessels than in the interstitium.
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| 5. |
- Börner, Katrin, 1979, et al.
(författare)
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Molecular imaging of lipids in cells and tissues
- 2007
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Ingår i: International Journal of Mass Spectrometry. - : Elsevier BV. - 1387-3806. ; 260:2-3, s. 128-136
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Tidskriftsartikel (refereegranskat)abstract
- The distribution pattern of lipid species in biological tissues was analyzed with imaging mass spectrometry (TOF-SIMS; time-of-flight secondary ion mass spectrometry). The first application shows distribution of a glycosphingolipid, the galactosylceramide-sulfate (sulfatide) with different hydrocarbon chain lengths and the fatty acids palmitate and oleate in rat cerebellum. Sulfatides were seen localized in regions suggested as paranodal areas of rat cerebellar white matter as well as in the granular layer, with highest concentrations at the borders of the white matter. Different distribution patterns could be shown for the fatty acid C16:0 palmitate and C18:1 oleate in rat cerebellum, which seem to origin partly from the hydrocarbon chains of phosphatidylcholine. Results were shown for two different tissue preparation methods, which were plunge-freezing and cryostat sectioning as well as high-pressure freezing, freeze-fracturing and freeze-drying. The second application shows TOF-SIMS analysis on a biological trial of choleratoxin treatment in mouse intestine. The effect of cholera toxin on lipids in the intestinal epithelium was shown by comparing control and cholera toxin treated mouse intestine samples. A significant increase of the cholesterol concentration was seen after treatment. Cholesterol was mainly localized to the brush border of enterocytes of the intestinal villi, which could be explained by the presence of cholesterol-rich lipid rafts present on the microvilli or by relations to cholesterol uptake. After cholera toxin exposure, cholesterol was seen increased in the nuclei of enterocytes and apparently in the interstitium of the villi. We find that imaging TOF-SIMS is a powerful tool for studies of lipid distributions in cells and tissues, enabling the elucidation of their role in cell function and biology.
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| 6. |
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| 7. |
- Eriksson, Cecilia, 1966, et al.
(författare)
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Implantation of hydrophilic and hydrophobic titanium discs in rat tibia: cellular reactions on the surfaces during the first 3 weeks in bone.
- 2004
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Ingår i: Biomaterials. - : Elsevier BV. - 0142-9612. ; 25:19, s. 4759-66
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Tidskriftsartikel (refereegranskat)abstract
- In a previous study, a method for evaluation of short-time (1-8 days) healing of titanium implants in rat tibiae was described (J. Biomed. Mater. Res. 66A(3) (2003) 662). The implants were disc-shaped and cells and tissue on the surface were investigated, not the adjacent tissue. In this study healing during the first 3 weeks in bone was examined and the healing response between hydrophilic and hydrophobic titanium was compared. Immunofluorescence techniques were used to detect signs of bone formation on the surfaces. Cell viability, alkaline phosphatase (ALP) activity, presence of osteocalcin and cells positive for bone morphogenetic protein-2 (BMP-2) and vascular endothelial growth factor (VEGF) were investigated. Both viable and non-viable cells were found on both surfaces during the first week. Only initially was there a difference between them; 4% viable cells on hydrophilic discs compared to 56% on hydrophobic ones. More BMP-2 positive cells were found on hydrophilic discs than on hydrophobic ones after 1 week. VEGF was detected after 8 days on both surfaces. Osteocalcin positive cells were found from 2 weeks. ALP positive cells were found after 8 days, while at 2-3 weeks ALP positive tissue was abundant on both surfaces. In conclusion, signs of bone formation were detected during the period investigated. Surface energy appeared to be of more importance initially, with higher surface energy resulting in more rapid cell activation and differentiation than lower.
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| 8. |
- Eriksson, Cecilia, 1966, et al.
(författare)
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Studies by imaging TOF-SIMS of bone mineralization on porous titanium implants after 1 week in bone
- 2006
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Ingår i: Applied Surface Science. - : Elsevier BV. - 0169-4332 .- 1873-5584. ; 252:19, s. 6757-6760
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Tidskriftsartikel (refereegranskat)abstract
- Anodic oxidation was used to grow porous layers on titanium discs. Six different oxidation procedures were used producing six different surfaces. The implants were inserted in rat bone (tibia) for 7 days. After implant retrieval, mineralization (hydroxyapatite formation) on the implant surfaces was investigated using time-of-flight secondary ion mass spectrometry (TOF-SIMS). Bone tissue around the implants was sectioned and stained. The amount of bone in close apposition to the implant was calculated. The porosity showed great variation between the surfaces. Hydroxyapatite was detected on all surfaces. A slight positive correlation between porosity and mineralization was found, although the most porous surface was not the best mineralized one. Bone had formed around all implants after 7 days. The bone-to-metal contact for the porous implants did not differ significantly from the non-porous control. Porosity is known to influence cellular events. The results indicate that porosity could have an initial, positive influence on bone integration of implants, by stimulating the mineralization process. The methods used were found to be suitable tools for investigation of initial healing around implants in bone.
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| 9. |
- Eriksson, Cecilia, et al.
(författare)
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Time-of-flight secondary ion mass spectrometric analysis of the interface between bone and titanium implants.
- 2008
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Ingår i: Rapid communications in mass spectrometry : RCM. - : Wiley. - 0951-4198 .- 1097-0231. ; 22:7, s. 943-9
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Tidskriftsartikel (refereegranskat)abstract
- Implant healing into bone tissue is a process where the mature bone grows towards and eventually fuses with the implant. In this study we investigated implant healing during 4 weeks with focus on the implant-tissue interface. Our main interest was to study the mineralization process around the implant. Titanium discs were implanted in rat tibia for 2 and 4 weeks. After implantation cross sections of bone and implant were made using a low-speed saw equipped with a diamond wafering blade. One section from each sample was stained with basic fuchsin and micrographed by light microscopy (LM). The other section was analyzed with imaging time-of-flight secondary ion mass spectrometry (TOF-SIMS) using a Bi(3)(+) cluster ion source. This ion source has recently been shown to enable identification of high-mass hydroxyapatite (HA) fragment ions (m/z 291-653) in bone samples. The LM images were used to identify areas suitable for TOF-SIMS analysis. Three areas were selected for mass spectral analysis, corresponding to interface region, bone and soft tissue, from which positive ion spectra were recorded. In the areas identified as bone, high-mass HA fragments ions were found after both 2 and 4 weeks. In the soft tissue area, no high-mass ions were found after 4 weeks. However, after 2 weeks HA-related ions were identified in mineralized spots in areas defined as soft tissue. After 4 but not after 2 weeks, high-mass HA fragment ions were found in the interface region. In conclusion, differences were observed regarding mineralization between 2 and 4 weeks of implantation and between different regions surrounding the implants. Imaging TOF-SIMS analysis using a Bi(3)(+) cluster as ion source enables identification of high-mass HA fragment ions at implant-tissue interfaces in bone. This technique might therefore be useful for biocompatibility assessment and for studying the mineralization process at implant surfaces.
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| 10. |
- Lange, Stefan, 1948, et al.
(författare)
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Binding of the VCHSKT peptide to ceramide-rich and cholesterol-rich domains of cell membranes in rat pancreatic glands
- 2013
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Ingår i: Surface and Interface Analysis. - : Wiley. - 0142-2421 .- 1096-9918. ; 45:1, s. 268-272
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Tidskriftsartikel (refereegranskat)abstract
- A peptide with antisecretory effect has been defined and was denoted the antisecretory factor (AF-16) with a sequence of 16 amino acids. A shorter sequence, the AF-6 peptide (VCHSKT, Pepceuticals Ltd, Leicester, England), is readily detected by Time of Flight Secondary Ion Mass Spectrometry (TOF-SIMS), using trifluoroacetic acid (TFA) as ionization catalyzer. Analysis of a reference sample revealed a pseudo-molecular ion at m/z 657 and M+Na+ at m/z 679. These peaks were also detected in tissue samples of animals exposed to the peptide. The AF-6 peptide was injected intravenously or sprayed into the nostrils of Sprague–Dawley rats, 250–300g (n=5). The animals were anesthetized with isoflurane. Pancreas tissue samples were taken after 2h and were high-pressure frozen in a Lecia EMPACT, sprayed with 0.1% TFA, and analyzed using a TOF-SIMS V instrument (ION-TOF, GmbH, Münster, Germany) equipped with a Bi3+-liquid metal ion gun at the University of Gothenburg. The distribution of the AF-6 peptide could be seen in the pancreas of exposed animals and control animals as high-intensity dots that were heterogeneously distributed in regions with a high intensity of phosphatidylcholine head group m/z 184, indicating a localization to the membrane portion of the pancreatic cells. The peptide was colocalized with a dot-like distribution of galactocylceramide c18:0 and cholesterol. Cholesterol and gal-Cer are known lipid components of specialized membrane areas called lipid rafts. The results indicate that the AF-6 peptide binds to cellular receptors present in such regions of rat pancreatic cells.
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