Electron microscopy

Last updated: Monday, 05, April, 2004

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Item Process
Specimen

Both tissue and virus samples may be examined by electron microscopy.

If electron microscopy studies are contemplated laboratory staff should be contacted.

  1. Main tissue types for electron microscopy investigation include:
    needle biopsy of the kidney for typing glomerulonephritis;
    tumour sample for typing poorly differentiated tumours;
    liver or other tissue for inherited metabolic disorders;
    sural nerve for peripheral neuropathy;
    muscle biopsy for myopathy; and
    turbinate biopsy for primary ciliary dyskiinesia.
  2. Virus samples include: blister fluid, swabs, and faecal suspension.
Method
  1. Tissue must be fixed as quickly as possible, this may necessitate collection from theatre. 
    Tissue is fixed in a buffered glutaraldehyde/formaldehyde fixative, cut into pieces less than 1mm in size, dehydrated, embedded in plastic, sectioned and examined. 
    Paraffin embedded tissue for light microscopy can be retrospectively used for electron microscopy, when reprocessed for electron microscopy can provide useful information.
  2. Viral sample is placed on a grid, negatively stained with a heavy metal salt and examined.
Application

Electron microscopy is useful for rapid viral identification and is important for typing glomerulonephritis. 

In tumour diagnosis where results from morphology and antibody labelling are equivocal electron microscopy can provide useful additional diagnostic information. 

For the other conditions such as metabolic inherited disorders, peripheral neuropathies, myopathies and primary ciliary dyskinesia, electron microscopy can provide a definitive diagnosis.

Interpretation

Requires experience, several of the important diagnostic text books are listed below.

Reference

EM Techniques:

Glauert AM ed. Practical Methods in Electron Microscopy. North Holland 1975.

Robards AW.  Procedures in Electron Microscopy. Wiley 1993.

Interpretation:

Dickerson GR. Diagnostic Electron Microscopy: a Text/atlas. Igalen-Shoin 1988.

Ghadially FN. Diagnostic Electron Microscopy of Tumours. Butterworths 1985.

Henderson DW et alUltrastructural Appearances of Tumours: Diagnosis and Classification of Human Neoplasia by Electron Microscopy. Churchill 1986.

Papadimitriou JM et al. Diagnostic Ultrastructure of Non-neoplastic Diseases. Churchill 1992.

Llombart-Bosch A ed. Semin Diagn Pathol 2003;  20: 1-81.