| 1. |
- Börner, Katrin, 1979, et al.
(author)
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Distribution of cholesterol and galactosylceramide in rat cerebellar white matter.
- 2006
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In: Biochimica et biophysica acta. - : Elsevier BV. - 0006-3002. ; 1761:3, s. 335-44
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Journal article (peer-reviewed)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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| 2. |
- Börner, Katrin, 1979, et al.
(author)
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Localization of Na+ and K+ in rat cerebellum with imaging TOF-SIMS
- 2006
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In: Applied Surface Science. - : Elsevier BV. - 0169-4332. ; 252:19, s. 6777-6781
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Journal article (peer-reviewed)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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| 3. |
- Nygren, Håkan, 1952, et al.
(author)
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Bioimaging TOF-SIMS: High resolution 3D imaging of single cells.
- 2007
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In: Microscopy research and technique. - : Wiley. - 1059-910X .- 1097-0029. ; 70:11, s. 969-74
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Journal article (peer-reviewed)abstract
- The distribution of phosphocholine ions (m/z 184, m/z 86), sodium ions, and potassium ions in thyroid tumor cells was analyzed by imaging TOF-SIMS. Repeated sputtering with a C(60) (+) source and subsequent analysis with a Bi(3) (+) gun produced a series of 138 images that were stacked to make a 3D display of the chemistry of cells. Phosphocholine was seen in the plasma membrane (m/z 184) and intracellular membranes (m/z 86). The different fragmentation of the phospholipid probably reflects the chemical composition of membranes at these sites. High intensity of secondary ion signals of potassium was seen in membrane-encompassed cellular compartments. The data indicate that potassium ions are compartmentalized in thyroid tumor cells.
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| 4. |
- Nygren, Håkan, 1952, et al.
(author)
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Imaging TOF-SIMS of rat kidney prepared by high-pressure freezing.
- 2005
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In: Microscopy research and technique. - : Wiley. - 1059-910X .- 1097-0029. ; 68:6, s. 329-34
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Journal article (peer-reviewed)abstract
- Phosphocholine, potassium ions, and sodium ions were localized in rat kidney with imaging TOF-SIMS. Tissue preparation was performed with high-pressure freezing, freeze-fracturing and freeze-drying. The distribution of sodium ions was visualized by imaging the signal at m/z 23 of positively charged secondary ions, and the distribution of potassium ions was visualized by imaging the signal at m/z 39. Potassium was found localized within cells of the proximal tubulus epithelium and within cells of the glomeruli. High signals of sodium ions were seen in the interstitial tissue and also in epithelial cells of the collecting ducts and in glomeruli. The overlay image showed that the distribution of sodium ions and potassium ions were largely complementary with color mixing in glomeruli and in the interstitium surrounding proximal tubules. The ion distribution was further analyzed by correlation analysis. Phosphocholine-containing phospholipids were visualized by imaging the phosphocholine head group at m/z 184 of positively charged ions. The m/z 184 signal shows a ubiquitous distribution with a high intensity of phosphocholine in epithelial cells. Overlay image of m/z 184, m/z 39, and m/z 23 and multivariate analysis showed that the localization of high levels of phosphocholine colocalizes with high levels of potassium ions, as expected for an ion with intracellular localization.
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| 5. |
- Nygren, Håkan, 1952, et al.
(author)
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Localization of cholesterol in rat cerebellum with imaging TOF-SIMS Effect of tissue preparation
- 2007
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In: Applied Surface Science. - : Elsevier BV. - 0169-4332. ; 252:19, s. 6975-6981
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Journal article (peer-reviewed)abstract
- Time-of-flight secondary ion mass spectrometry (TOF-SIMS) was utilized to address the issue of cholesterol localization in rat cerebellum, a subject not previously investigated. Rat cerebellum was prepared by three different procedures: (1) fixation in formaldehyde, freeze-protection by sucrose, freezing in liquid nitrogen and sectioning by cryoultramicrotomy and drying at room temperature or (2) freezing in liquid nitrogen, cryostat sectioning at −40 °C and drying at room temperature or (3) high-pressure freezing, freeze-fracturing and freeze-drying. The samples were analyzed in an imaging TOF-SIMS instrument equipped with a Bi1–7+-source. The cholesterol signal (m/z 369 and 385), showed high intensity in the glial cells in white matter and lower intensity in Purkinje cells and in nuclei of granular layer cells. Specimen treated by procedure 1 showed some signs of diffusion of cholesterol in the tissue. Specimen treated by procedure 2 showed freeze-damage of the cells. Specimen treated by procedure 3 showed distinct localization of cholesterol in well preserved tissue. Thus, high-pressure freezing and freeze-fracturing was used for further characterization of the distribution of cholesterol in rat cerebellum.
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| 6. |
- Nygren, Håkan, 1952, et al.
(author)
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Localization of cholesterol, phosphocholine and galactosylceramide in rat cerebellar cortex with imaging TOF-SIMS equipped with a bismuth cluster ion source.
- 2005
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In: Biochimica et biophysica acta. - : Elsevier BV. - 0006-3002. ; 1737:2-3, s. 102-10
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Journal article (peer-reviewed)abstract
- Time-of-flight secondary-ion-mass-spectrometry (TOF-SIMS) was utilized to address the issue of co-localization of cholesterol, phosphocholine and galactosylceramide in rat cerebellar cortex. Rat cerebellum was fixed, freeze-protected by sucrose, frozen and sectioned by cryoultramicrotomy and dried at room temperature. The samples were analyzed in an imaging TOF-SIMS instrument equipped with a Bi(1-7)+-source. The cholesterol signal (m/z 369 and 385) was localized in Purkinje cells and in nuclei of granular layer cells. The phosphocholine headgroup of phosphatidylcholine and sphingomyelin was localized by imaging a specific fragment (m/z 86). This signal was localized in the molecular layer of cerebellar cortex, in Purkinje cells and in parts of the granular layer probably representing the synapse-rich glomeruli. The galactosylceramide was localized by imaging the quasi-molecular ions at m/z 835 and 851, showed a clear colocalization with cholesterol, but also a specific localization in dots (diameter
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| 7. |
- Richter, Katrin, 1979, et al.
(author)
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Localization of fatty acids with selective chain length by imaging time-of-flight secondary ion mass spectrometry.
- 2007
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In: Microscopy research and technique. - : Wiley. - 1059-910X .- 1097-0029. ; 70:7, s. 640-7
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Journal article (peer-reviewed)abstract
- Localization of fatty acids in biological tissues was made by using TOF-SIMS (time-of-flight secondary ion mass spectrometry). Two cell-types with a specific fatty acid distribution are shown. In rat cerebellum, different distribution patterns of stearic acid (C18:0), palmitic acid (C16:0), and oleic acid (C18:1) were found. Stearic acid signals were observed accumulated in Purkinje cells with high intensities inside the cell, but not in the nucleus region. The signals colocalized with high intensity signals of the phosphocholine head group, indicating origin from phosphatidylcholine or sphingomyelin. In mouse intestine, high palmitic acid signals were found in the secretory crypt cells together with high levels of phosphorylinositol colocalized in the crypt region. Palmitic acid was also seen in the intestinal lumen that contains high amounts of mucine, which is known to be produced in the crypt cells. Linoleic acid signals (C18:2) were low in the crypt region and high in the villus region. Oleic acid signals were seen in the villi and stearic acid signals were ubiquitous with no specific localization in the intestine. We conclude that the results obtained by using imaging TOF-SIMS are consistent with known brain and intestine biochemistry and that the localization of fatty acids is specific in differentiated cells.
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