In
pathology, the Grocott-Gomori's (or Gömöri)
methenamine silver stain In pathology, silver staining is the use of silver to selectively alter the appearance of a target in microscopy of histological sections; in temperature gradient gel electrophoresis; and in polyacrylamide gels.
In traditional stained glass, si ...
, abbreviated GMS, is a popular
staining
Staining is a technique used to enhance contrast in samples, generally at the microscopic level. Stains and dyes are frequently used in histology (microscopic study of biological tissues), in cytology (microscopic study of cells), and in the ...
method in
histology. The stain was originally named after
György Gömöri
György Gömöri (also George Gömöri or George Gomori; 1904–1957) was a Hungarian-American physician who became famous as a histochemist.
Gömöri was born in Budapest on 16 July 1904. He received a degree from the medical faculty of the Pá ...
, the Hungarian physician who developed the stain.
It is used widely as a screen for
fungal organisms. It is particularly useful in staining carbohydrates.
It can be used to identify the yeast-like fungus ''
Pneumocystis jiroveci'',
which causes a form of
pneumonia called
''Pneumocystis'' pneumonia (PCP) or
pneumocystosis.
The
cell walls
A cell wall is a structural layer surrounding some types of cells, just outside the cell membrane. It can be tough, flexible, and sometimes rigid. It provides the cell with both structural support and protection, and also acts as a filtering mech ...
of these organisms are outlined by the brown to black stain.
The principle of GMS is the
reduction of
silver ions, which renders the fungal cell wall black. The fungal cell wall commonly contains
polysaccharides. In a GMS procedure,
chromic acid is first used to oxidize polysaccharides, generating
aldehydes. Then Grocott's alkaline hexamine-silver solution is applied, where the silver ions are reduced to black amorphous silver. The reduction reaction by the fungal cell wall is often known as argentaffin reaction.
See also
*
Methenamine
References
{{DEFAULTSORT:grocott's Methenamine Silver Stain
Staining