Microscopic Examination of Stained Blood Films
Paul Ehrlich had used mixtures of acidic and basic dyes for this purpose in 1879: e.g. Fuchsine (acid dye) and methylene blue (basic dye). In 1891 Ernst Malachowski and Dmitry Leonidovich Romanowsky independently developed techniques using a mixture of Eosin Y and modified Methylene blue that produced a surprising hue unattributable to either staining component: a beautiful, distinctive shade of purple. Requirement for the occurrence of the Malachowski-Romanowsky-Giemsa effect are: I A cationic dye: The best dye is azure B and, though azure A gives the nuclear purple colour, the cytoplasmic blue is inferior. No other cationic dye such as methylene blue is suitable. 2 An anionic dye: Most commonly eosin Y is used. Because the aqueous dye solutions were unstable, methanol was introduced as a solvent, and William Boog Leishman y James Homer Wright advocated use of methanol as a fixative prior to staining. Gustav Giemsa improved this technique by standardizing the dye solutions and adding glycerol to increase stability.
The demethylation of Methylene Blue in aqueous solution using heat and alkali produces a mixture of Azure A, Azure B, Methylene Violet and Methylene Blue. Eosin Y is then added to produce a "neutral" dye. The precipitate is then dissolved in a mixture of methanol and glycerol to form a stock solution; this is diluted with water or an aqueous buffer to form a 'working' solution that is used in the staining of pathology specimens. The 'working' solution is stable for 3 hours.
Immunochromatographic capture procedures (Rapid Diagnostic Tests) are nonmicroscopic diagnostic options for the laboratory that may not have appropriate microscopy expertise available.
Read more about this topic: Romanowsky Stain
Famous quotes containing the words microscopic, examination, stained, blood and/or films:
“The television screen, so unlike the movie screen, sharply reduced human beings, revealed them as small, trivial, flat, in two banal dimensions, drained of color. Wasn’t there something reassuring about it!—that human beings were in fact merely images of a kind registered in one another’s eyes and brains, phenomena composed of microscopic flickering dots like atoms. They were atoms—nothing more. A quick switch of the dial and they disappeared and who could lament the loss?”
—Joyce Carol Oates (b. 1938)
“Maybe it’s understandable what a history of failures America’s foreign policy has been. We are, after all, a country full of people who came to America to get away from foreigners. Any prolonged examination of the U.S. government reveals foreign policy to be America’s miniature schnauzer—a noisy but small and useless part of the national household.”
—P.J. (Patrick Jake)
“Near vermillion one gets stained red; near ink one gets stained black.”
—Chinese proverb.
“No person connected with me by blood or marriage will be appointed to office.”
—Rutherford Birchard Hayes (1822–1893)
“Science fiction films are not about science. They are about disaster, which is one of the oldest subjects of art.”
—Susan Sontag (b. 1933)