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Apply for self-reported educational credits. Preparation options Because of the microscopy requirements, options for preparing specimens are limited to: Whole-mounts, where an entire organism or structure is small enough or thin enough to be placed directly onto a microscope slide e.
Sections, where specimens are supported in some way so that very thin slices can be cut from them, mounted on slides, and stained. Section preparation. Figure 1: A diagnostic section being prepared with a cryostat microtome. The section, which has been cut from snap-frozen tissue, is being picked up onto a warm slide where it will be immediately fixed and stained.
Figure 2: A rotary microtome being used to cut paraffin sections. Specimen reception. Figure 3: A fresh, unfixed specimen after surgical removal.
To prevent degeneration or drying out, the specimen should be fixed as soon as possible. Figure 4: A surgical specimen fixing in formalin and ready for grossing. Note that there is a generous volume of fixative compared to the size of the specimens.
A cassette that will contain the specimen during processing has already been printed with patient identifiers. Figure 5: This surgical specimen of stomach has been fixed in formalin. Slices about 4mm thick will now be taken from appropriate areas and placed in the labeled cassettes for processing. Figure 6: A tissue processor being loaded with a basket of cassettes containing tissue specimens for processing.
Details of the processing steps and the schedule are shown on the screen of the processor. Figure 7: Processed tissue blocks are embedded into wax molds and placed on a cold plate to cool and solidify. Figure 8: A ribbon of sections being cut from a paraffin block using a rotary microtome. Figure 9: A paraffin section being mounted on a microscope slide after being floated out on warm water to flatten it.
To prevent charge buildup on specimen surface, it is coated with a conductive material, most commonly gold. The metal is applied in a controlled manner in a sputter coater. It is critical that the coating is thick enough to prevent charging typically around 10 nm but not thick enough to obscure specimen surface details.
Array tomography allows collection of images very similar to TEM images, but using a SEM, and from hundres and even thousands of serial sections. These images can then be used to reconstruct a 3D image at ultrustructural detail.
However, instead of on grids the serial sections are mounted on conductive silica wafers or glass substrates. Successful cutting of so many serial sections is facilitated by two tools: advanced substrate holder ASH and AtumTOME — a system for automated collection of sections on a tape. ASH typically allows collection of up to a few hundreds of relatively small sections and the operator is required to mount the sections directly on a wafer. AtumTOME allows collection of up to tousands of larger sections on a steadily moving tape without the operator being present.
The tape is then cut into strips and mounted on large silica wafers. Notice: Some functionality may be limited if JavaScript is disabled, please enable JavaScript for a better experience. Menu Menu. Swedish International website. Find staff. Flegler, S. Scanning and transmission electron microscopy. Freeman and Co.
Franks, L. Origin and ultrastructure of cells in vitro. In: G. Bourne, J. Danielli, and K. Jeon eds. Academic Press, New York. Ghadially, EN. Diagnostic electron microscopy of tumors , 2nd edn. Butterworths, London. Ultrastructural pathology of the cell and matrix , 4th edn. Butterworth-Heinemann, London. Giberson, R. Microwave techniques and protocols.
Humana Press, Totowa, NJ. Gilkey, J. Advances in ultrarapid freezing for the preservation of cellular ultrastructure. Electron Microsc. Glauert, A. Fixation, dehydration and embedding of biological specimens. Elsevier North-Holland, New York. A new embedding medium for electron microscopy.
Nature Biological specimen preparation for transmission electron microscopy. In: A. Glauert ed. Hanstede, J. The effects of embedding in water-soluble plastics on the final dimensions of liver sections. Hayat, M. Principles and techniques of electron microscopy: Biological applications Vol.
Van Nostrand Reinhold, New York. Fixation for electron microscopy. Electron microscopy: Biological applications , 4th edn. Cambridge University Press, New York. Heckman, CA. GACH: A water-miscible, lipid-retaining embedding polymer for electron microscopy.
Ultrastruct Res. Hopwood, D. Some aspects of fixation with glutaraldehyde: A biochemical and histochemical comparison of the effects of formaldehyde and glutaraldehyde fixation on various enzymes and glycogen with a note on penetration of glutaraldehyde into liver. Theoretical and practical aspects of glutaraldehyde fixation. In: PJ. Stoward ed. Karnovsky, M. A formaldehyde-glutaraldehyde fixative of high osmolality for use in electron microscopy.
Cell Biol.
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