Osis veleta digital slow scan 2k 2k ccd camera

Following centrifugation, the supernatant was replaced and the sample pellets re-suspended and rinsed in 0.15 M sodium cacodylate buffer (pH 7.2), three times. Next, the sample pellets were embedded in low-melting point agarose and postfixed in 1% w/v OsO₄ in 0.12 M sodium cacodylate buffer (pH 7.2) for 2 h. The specimens were dehydrated in graded series of ethanol, transferred to propylene oxide and embedded in Epon according to standard procedures. Sections, approximately 80 nm thick, were cut with a Leica Ultra microtome UC7 and collected on copper grids with Formvar supporting membranes, stained with uranyl acetate and lead citrate, and subsequently examined with a Philips CM 100 TEM (Philips, Eindhoven, Netherlands), operated at an accelerating voltage of 80 kV. Digital images were recorded with an OSIS Veleta digital slow scan 2k × 2k CCD camera (Olympus, Germany) and the ITEM software package.

Electron microscopy was performed in the Core Facility for Integrated Microscopy, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark. Carbon-coated copper grids (200 mesh; Ted Pella Inc.) were glow-discharged with a Leica EM ACE 200 (Leica Biosystems Nussloch GmbH), and loaded with 6 µL of sarkosyl-insoluble sample. The sample was adsorbed for 1 min, blotted and stained with 2% phosphotungstic acid in dH₂0 for 2 min. After blotting and a quick wash with dH₂0, the samples were examined with a Philips CM 100 TEM (Koninklijke Philips N.V.), operated at an accelerating voltage of 80 kV. Digital images were acquired at a nominal magnification of x180,000, by using an OSIS Veleta digital slow scan 2k × 2k CCD camera and the iTEM software package (Olympus Corporation). Filaments shorter and longer than 200 µm were analysed in at least two fields of view with ImageJ software. Reported values are mean ± SEM of 70 and 32 PHFs for APP_swe/PS1_ΔE9 and AD tissue, respectively.