NATURAL AND SYNTHETIC DYES Flashcards
HEMATOXYLIN is a natural dye derived by extraction from the core or the heartwood of a Mexican tree called
Hematoxylin campechianum
- It is by far the most valuable staining reagent used by the cytologists due to its powerful nuclear and chromatin staining capacity
HEMATOXYLIN
-It is not a true basic dye
HEMATOXYLIN
- It is essential that the oxidant be used in correct amount, since excessive oxidation leads to production of other useless compounds. Using the least amount of oxidant will result in satisfactory staining and longer life of the stain.
HEMATOXYLIN
-Old histologic dye extracted from the female cochineal bug (Coccus cacti)
Cochineal Dyes
-treated w/ alum
Carmine (Dye)
-Widely used powerful chromatin and nuclear stain for fresh material and smear prep.
Cochineal Dyes
Demonstration of GLYCOGEN
Carmine + Aluminum chloride (Best’s Carmine)
Neuropathological studies
Carmine + Picric acid(Picrocarmine)
vegetable dye extracted from certain lichens which are normally colorless
Orcein
-treated w/ ammonia + air
Blue or Violet colors
- weak acid, soluble in alkali
Orcein
- used to stain Elastic fibers
- It is now primarily used as an indicator
Orcein
-known as” Coal Tar Dyes”
SYNTHETIC DYES
______-are derived from the hydro-carbon benzene (C6H6) and are collectively known as _________
SYNTHETIC DYES, Aniline dyes
are substances w/ definite atomic groupings and capable of producing visible color
Chromophores –
- Before a chromogen can properly be called a dye, it must have the property of retaining its color in the tissue. This property is acquired by the addition of an
auxochrome
Dye Classification
Acid dyes, Basic dyes, and Neutral dyes
where the active coloring substance is found in the acid component, and the inactive base, e.g acid fuchsin, is usually the sodium salt of a sulfonate of rosaniline.
Acid Dyes
Where the active coloring substance is found in a basic component that combines with the acid radical
Basic Dyes –
Example of acid dyes
Acid fuchsin Picric acid (fix, differentiate or stain)
Example of basic dyes
Methylene blue (both indicator and dye)
are formed by combining aqueous solutions of acid and basic dyes, capable of staining
cytoplasm and nucleus simultaneously and differentially.
Neutral Dyes
Examples of Neutral Dyes
Romanosky dyes
Giemsa’s stain
Irishman’s stain –> leukocyte differentiation
(recommended for progressive staining)
Aluminum hematoxylin
used for regressive staining
Ehrlich Hematoxylin
- Sodium iodate hastens ripening process
- Suitable for tissues that have been subjected to acid decalcification
Ehrlich Hematoxylin
exfoliating Cytology & sex chromosomes
Harris Hematoxylin
exfoliating Cytology & sex chromosomes
Harris Hematoxylin
- Ripened by Mercuric oxide/chloride
- The addition of 4% glacial acetic acid will give a more precise nuclear staining
Harris Hematoxylin
- Another alum hematoxylin solution recommended for routine purposes, especially used in sequence with
Celestine blue. - Artificially ripened with alcoholic iodine solution
Cole’s Hematoxylin
ripened w/ sodium iodate
Mayer’s Hematoxylin
- It can be used as regressive stain, but it is also useful as a progressive stain
Mayer’s Hematoxylin
During staining, alum hematoxylin stained sections are usually passed on to an alkaline solution in order to neutralize the acid and free the OH group, to form an insoluble blue aluminum hematin-tissue-lake.
Blueing
Examples of Blueing agents:
Tap water, Lithium Carbonate, Bicarbonate, potassium or Sodium acetate may be used
- used only for differential and regressive staining, using acid-alcohol as a differentiating agent.
Iron Hematoxylin
uses Ferric chloride as Mordant
Weigert’s Hematoxylin –
Uses Ferric Ammonium chloride as the Mordant
Heidenhain’s Hematoxylin
Modification of Iron Hematoxylin used to demonstrate Mitochondria
Regaud’s Hematoxylin for Mitochondria
Examples of iron hematoxylin
Weigert’s
Heidenhain’s
Regaud’s
- also known as the original Mallory PTAH technique, combining hematoxylin with 1% aqueous phophotungstic acid, which acts as a mordant
Phosphotungstic Acid Hemtoxylin (PTAH)
one of the most valuable stains used for differentially staining connective tissue and cytoplasm
EOSIN
It is a red general cytoplasmic stain that combines with hemoglobin to give an orange color
EOSIN
- Cytoplasmic stain
- Commonly used as counterstain in H &E
eosin
the commonly used, showing green yellow fluorescence especially in alcoholic medium.
Eosin Y-
very faint bluish cast
Eosin B
rarely used eosin
Eosin S
It is the most common staining technique in histopathology. This uses a
combination of two dyes, Hematoxylin and Eosin used for demonstration of nucleus and cytoplasmic inclusions in clinical
specimens.
Hematoxylin and Eosin (H & E) staining
Principle of H & E staining
Alum acts as mordant and hematoxylin containing alum stains the nucleus light blue
Example of a Basic stain. A. Methylene blue B. Neutral Red C. Fuchsin D. Romanowsky dye
A
Heidenhain’s Hematoxylin uses __________ as a mordant.
C.Ferric Ammonium Chloride
. What dye is Normally Colorless but when treated with ammonia and exposed to air, produces blue or violet colors?
Orcein
What is added to Chromogen to improve the retaining of color?
Auxochrome
Simple benzene compounds + Chromophores=?
Chromogen
