Clara Pecorella is a Laboratory Technician/Product Specialist from Italy, working in the Innovation Department at Diapath S.p.A. Clara Pecorella was the 2019 winner of NSH’s Art of the Stain Contest, a Histotechnology Professionals Day activity in which histotechs submit their favorite stains to be voted on by the NSH membership. Her stain, pictured below, attracted the attention of our members for its similarity to an impressionist painting, something Clara herself agrees with. We asked Clara to share with us more detail about this beautiful stain!
Clara: The M.S.B. method (Martius yellow, Scarlet, Blue – Lendrum et al. 1962) is a reliable technique for the selective demonstration of fibrin and qualifies as a trichrome staining in which three types of coloring agents are used.
The general rule in trichrome staining is that less porous tissues are stained by smaller dye molecules. Whenever a larger dye molecule is able to penetrate the tissue, it will always do so at the expense of smaller molecules.
The main feature of the M.S.B. method is the use of the Martius yellow stain, a small stain molecule that, together with the phosphotungstic acid in alcoholic solution, stains the red blood cells. Early fibrin deposits are stained with this dye, while phosphotungstic acid blocks the staining of muscle fibers, collagen and connective tissue. The Ponceau staining of xylidine (Scarlet) is a medium-sized molecule and stains muscle fibers and mature fibrin. During this phase the gross staining of collagen is prevented by the phosphotungstic acid that remained from the previous step. Further treatment with phosphotungstic acid will remove any trace of red from the collagen fibers. Finally, the blue aniline dye, a large molecule, stains the collagen and the old fibrin deposits.
The staining was carried out manually using the M.S.B. kit of the company Diapath S.p.A. (kit code M.S.B. 010255).
The picture was sent to the contest because the work of the laboratory technician, in histochemical practice, can be compared to that of an artist with his canvas. Specifically, the M.S.B. reminds me of an impressionist painting and it could be a painting by Vincent Van Gogh or Claude Monet.