Re: Defanos stain (Da Fano's method)

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From:"J. A. Kiernan" <>
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On Sat, 11 Mar 2000 wrote:

> what is the Defano's stain,what does it stain, and what is a good 
> control?Procedure wpuld be helpful.

  Do you mean Da Fano's?

  It's a traditional method for staining the Golgi apparatus.
  Small, fresh pieces are fixed for varying times in Da Fano's
  solution, which contains formalin and cobalt chloride. They are 
  then impregnated with silver nitrate, reduced with a developer,
  embedded in paraffin and thinly sectioned. Optionally the
  sections can be toned, traditionally in a gold-thiocyanate 
  mixture, though 0.1% gold chloride is OK.

  The critical step is the duration of fixation: try 3, 4, 5
  and 6 hours. Related methods use cadmium or barium chloride
  instead of cobalt.

  In nervous tissue the Golgi apparatus, when stained, shows
  as ragged ring around the nucleus; best seen in large neurons.

  There are other silver methods for the Golgi: Aoyama's,
  Saxena's etc, and also methods using osmium tetroxide
  (e.g. Ludford, Cowdry). Anyone intending to stain the
  Golgi apparatus for light microscopy should get 3 or 4
  text books from a library and look over the available 
  methods before deciding which is most appropriate for
  the species and the tissue to be studied.

 John A. Kiernan,
 Department of Anatomy & Cell Biology,
 The University of Western Ontario,
 LONDON,  Canada  N6A 5C1

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