The Argentaffni Reaclioji 247 



results: 



tyrosine proteins — pink to brie k red 



Ninhydrin Reaction (serra, 1946) 

 fixation: 10% formalin. 



solution: 

 Ninhydrin: 



phosphate buffer, pH 6.98, page 418. 



ninhydrin, 0.4% aqueous (triketo-hydrindene-hydrate) 

 Mix equal amoimts for staining. 



procedure: 



1. Deparaffinize and hydrate slides to water, or use frozen sections. 



2. Place slides on a rack over boiling water, cover with stain, and 

 steam for 1-2 minutes. 



3. Drain stain off the slide and motmt in glycerol jelly. 



results and comment: 



Blue or violet color indicates the presence of amino acids, peptides, 

 and proteins. The slide should be examined at once because the color 

 diffuses readily and begins to fade within a day or two. 



The Argentaffin Reaction 



The argentaffin reaction should not be conftised ^vith silver impreg- 

 nation (page 175). In argentaffin reactions some substances (ascorbic 

 acid, aldehydes, uric acid, polyphenols, and others) reduce silver solu- 

 tions under specific conditions. This reaction with the tissue itself, 

 therefore, can be used histochemically to identify these substances. 



The only source of error in the method can be found in calcification 

 areas, but only if these are in large masses. Most siher phosphates and 

 carbonates Avill be dissolved out during the the process. If not, the 

 slides can be treated with 0.2 to 0.5%, nitric acid or hydrochloric acid 

 in absolute alcohol, 2-3 minutes before step 3 below. Wash off the acid 

 in absolute and 95% alcohol and then proceed with step 3. 



Uric Acid Staining 



Argentaffin Method (gomori, 1952) 

 fixation: 95% or absolute alcohol. 



