An official website of the United States government
The .gov means it's official. Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you're on a federal government site.
The site is secure. The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.
Fig. 2. Visible, μFTIR and fluorescence images of a section of transgenic mouse brain containing the hippocampus. (a) Photomicrograph; dense core plaques appear darker than surrounding tissue. The box (black) indicates an area where a fluorescence image was obtained. (b) FTIR image showing the distribution of the integrated absorbance of the intermolecular β-sheet structures in the range 1645–1622 cm–1 (baseline at 1716–1595 cm–1). (c) Fluorescence image of the section stained with amylo-glo for Aβ peptide. (d) Composite image formed by overlaying the FTIR and fluorescence (white pixels) images.. From: Detection of Aβ plaque-associated astrogliosis in Alzheimer's disease brain by spectroscopic imaging and immunohistochemistry †Electronic supplementary information (ESI) available. See DOI: 10.1039/c7an01747b .
CitationFull text
Fig. 4. (Top panel) Self-organising map principal component analysis (SOM PCA) results derived from a Raman map of a plaque in a transgenic mouse brain hippocampal section. The Raman map was acquired over a 92 × 92 μm2 area using a 1.4 μm step-size. Map scores refer to the distribution of the (a) SOM PC1, which denotes the β-sheet core of the plaque, and (b) SOM PC2, showing the lipid halo surrounding the plaque core. Corresponding loading plots are shown in Figure SI-3. (Bottom panel) Immunofluorescence images at 20× magnification of a large plaque within a section of TG mice brain containing the hippocampus stained with (c) amylo-glo for Aβ peptide and (d) GFAP for astroglia. The plaque represented in (a) and (b) is different from the one in (c) and (d). Arrows indicate the location of processes and cell bodies. Segments denote the size of the plaque core and lipid ring, providing a measure of the lipid ring width-to-plaque core diameter of approximately 0.5 in both types of images.. From: Detection of Aβ plaque-associated astrogliosis in Alzheimer's disease brain by spectroscopic imaging and immunohistochemistry †Electronic supplementary information (ESI) available. See DOI: 10.1039/c7an01747b .
Fig. 1. (Top panel) Visible and μFTIR images of a section of transgenic mouse brain containing the hippocampus. (a) Photomicrograph. Acronyms, which identify specific regions of the hippocampal CA1 region, are defined in the text. The FTIR images refer to the distribution of the integrated absorbance of (b) lipid ν(CO)ester (1761–1722 cm–1), (c) ν(CH) (3003–2805 cm–1), (d) amide I (1716–1595 cm–1), (e) amide II (1593–1483 cm–1), and (f) intermolecular β-sheet structure (1640–1620 cm–1 with baseline at 1716–1595 cm–1). (Bottom panel) Spectra, visible and μFTIR images of an amyloid plaque extracted from the same measurement. The FTIR images refer to the distribution of the integrated absorbance of (k) amide II and (l) lipid ν(CO)ester bands. The lipid ring can be clearly seen in (l). Cursors indicate the same pixel in correspondence of the plaque core. Black dots in (k) indicate the pixels from which FTIR spectra were selected along a horizontal line from the core through to the margin of the plaque. Spectra are colour coded to match the colours in image (k). (g) Main absorption bands are assigned to NH stretching (amide A and B; 3600–3000 cm–1), CH stretching (3000–2800 cm–1), lipid ν(CO)ester (1761–1722 cm–1), amide I (1718–1600 cm–1), amide II (1590–1480 cm–1), phosphate and amide III (1270–1180 cm–1), phosphate and sugars (1096–1016 cm–1). Bold labels refer essentially to lipid bands. (h) FTIR spectra normalized to the maximum of NH stretching and amide I bands for the regions at high and low wavenumbers, respectively. Note that no baseline correction was applied to the spectra. (i) Arrow indicates the spectral change, i.e. a decrease in intermolecular β-sheet structures, going from the core to the periphery of the plaque, corresponding to the black dots in (k).. From: Detection of Aβ plaque-associated astrogliosis in Alzheimer's disease brain by spectroscopic imaging and immunohistochemistry †Electronic supplementary information (ESI) available. See DOI: 10.1039/c7an01747b .
Fig. 3. (Top and middle panels) Photomicrographs, μFTIR images and Raman principal component analysis (PCA) score maps of a transgenic mouse brain hippocampal section. Black box in (a) indicates a specific plaque area within the whole tissue FTIR image. The FTIR images refer to the distribution of the integrated absorbance of the (b) amide II (1588–1482 cm–1) and (c) lipid ν(CO)ester band (1761–1722 cm–1), and of the (d) height of the β-sheet peak (at 1628 cm–1). Colour scale limits are (b) 15 to –1.5, (c) 1.5 to 0.5, and (d) 0.9 to –0.09. Black box in (e) denotes a 99 × 99 μm2 area (same plaque as in a) where a Raman map was acquired using a 1.4 μm step-size. Map scores were derived from PCA applied to the Raman map and refer to the distribution of (f) average spectrum, (g) lipid-rich envelope and (h) β-sheet protein core(s) of the plaque. (Bottom panel) Representative FTIR spectra and Raman loading plots of a plaque. (i) Spectra extracted from a μFTIR image () and normalized with respect to the amide I band peak absorbance. Amide I peak position is 1651 cm–1 for the core and 1654 cm–1 for the ring, indicative of protein's α-helix conformation; the core spectrum has a doublet bandshape for the amide I mode. A difference spectrum was obtained by subtracting the ring profile from the core profile; it shows a loss of absorbance for the core spectrum at ca. 1738 cm–1 (lipid esters) and a gain at 1628 cm–1 (intermolecular β-sheets) and 1404 cm–1 (not fully clarified signature of the plaque core, slightly shifted to the position found in a different mouse model). (j) Loading plots extracted from PCA applied to the Raman map (in the middle panel). PC3 corresponds to the core spectrum and presents the distinctive amide I symmetric peak of the β-sheet conformation at 1667 cm–1, whilst PC2 represents the ring, with resonances due to lipids (distinctive bands at 1434 (CH2 deformation) and 1123 cm–1 (C–C stretching)) and other protein conformations (1648 cm–1, assigned to α-helix and random coils). PC1 denotes the mean spectrum of the tissue.. From: Detection of Aβ plaque-associated astrogliosis in Alzheimer's disease brain by spectroscopic imaging and immunohistochemistry †Electronic supplementary information (ESI) available. See DOI: 10.1039/c7an01747b .
Your browsing activity is empty.
Activity recording is turned off.
Turn recording back on