H&E Techniques Flashcards

Comprehensive vocabulary flashcards covering dyes, classification, mordants, staining methods, hematoxylin formulations, and staining procedures based on the lecture transcript.

Hematoxylin and Eosin Stain (H&E)

The most widely used histological stain, valued for its comparative simplicity and ability to clearly demonstrate a vast number of tissue structures by staining cell nuclei blue-black and cytoplasm pink.

Stain

A chemical substance used to achieve visible color contrast in the microscopic picture of a prepared tissue.

Staining

The process of treating tissues or cells with a series of reagents so that they acquire color without visible dye particles, leaving the stained element transparent.

Dye

An aromatic benzene ring compound or derivative that possesses the twin properties of color and the ability to bind to tissue.

Acidic Dye

A dye that stains basic tissue components such as cytoplasm and acidophil granules, with examples including Eosin and Acid Fuchsin.

Basic Dye

A dye that stains acidic tissue components such as nucleus and basophil granules, with examples including Hematoxylin, Basic Fuchsin, and Methylene Blue.

Neutral Dye

A dye consisting of a mixture of basic and acidic dyes in which both cations and anions contain chromophoric groups and colored radicals, such as Romanowsky dyes.

Mordant

A polyvalent metal ion that forms coordination complexes with dyes, acting as a chemical bridge or intermediary to increase the affinity between dye and tissue.

Lake

The insoluble mordant-dye complex formed when a mordant combines with a dye, which subsequently combines with tissue to form an insoluble tissue-mordant-dye complex.

Accentuator

A substance that increases the staining power, intensity, and selectivity of a dye without acting as a mordant, such as KOH in Löffler's methylene blue or phenol in carbol fuchsin.

Accelerator

An accentuator specifically used in metallic impregnation techniques for the nervous system, such as chloral hydrate.

Trapping Agent

An agent that holds a dye combination with tissue or bacteria, such as tannic acid or iodine.

Direct Staining

A staining reaction in which tissue is directly penetrated by a dye solution without an intermediate reagent.

Indirect Staining

A staining reaction that utilizes intermediate treatment with a mordant to bind the dye to tissue.

Physical Staining

A staining mechanism based on the simple solubility of a dye in an element of tissue.

Chemical Staining

A staining reaction that forms a new chemical substance within the tissue, such as the Periodic acid–Schiff (PAS) reaction.

Adsorption Phenomenon

A staining reaction process involving the accumulation of dye on the surface of a compound.

Vital Staining

Staining applied to living tissue by injecting a staining solution into the body or mixing stain directly with living cells, primarily used for research.

Routine Staining

Staining that colors tissues with minimal differentiation except between nucleus and cytoplasm to demonstrate general relationships among cells, tissues, and organs.

Special Staining

Staining techniques used to demonstrate selective features of tissues, such as specific cell products or intracellular and intercellular structures.

Regressive Staining

A technique where tissue is initially overstained and then partially decolorized (differentiated) under microscopic control until the desired endpoint is reached.

Progressive Staining

A technique where tissue is stained for a predetermined time until adequate coloration is achieved, without subsequent dye removal or differentiation.

Differentiation

The selective removal or washing out of excess stain using acid alcohol or ethyl alcohol until color is retained only by the tissue component being studied.

Armamentarium in Staining

The collection of tools, equipment, facilities, and reagents (such as Coplin jars, staining troughs, slide racks, and hot plates) required for staining in a laboratory.

Haematoxylon campechianum

The tree from whose heartwood or core natural hematoxylin dye is extracted.

Hematein

The major oxidation product of hematoxylin, serving as the active natural dye responsible for its color properties.

Ripening

The oxidation process converting hematoxylin into hematein, which occurs either naturally by exposure to light and air or chemically using oxidizing agents.

Ehrlich’s Hematoxylin

A naturally ripened strong alum hematoxylin that stains nuclei crisply, resists fading, and is suitable for decalcified tissue, cartilage, mucin, and long-stored formalin specimens.

Mayer’s Haematoxylin

A widely used alum hematoxylin chemically ripened with sodium iodate, containing chloral hydrate as a preservative and citric acid to sharpen nuclear detail.

Harris’s Haematoxylin

An alum hematoxylin traditionally chemically ripened with mercuric oxide, used regressively in routine histology and progressively in diagnostic exfoliative cytology.

Gill’s Haematoxylin

An alum hematoxylin available in three concentrations (I, II, III), stabilized with ethylene glycol to inhibit auto-oxidation, and prepared without boiling.

Cole’s Haematoxylin

An alum hematoxylin artificially ripened with an alcoholic iodine solution, known for good keeping qualities and suitability for use in sequence with celestine blue.

Carazzi’s Hematoxylin

An alum hematoxylin chemically ripened with potassium iodate, used as a progressive nuclear counterstain primarily on urgent frozen sections.

Delafield’s Hematoxylin

A naturally ripened alum hematoxylin prepared with ammonium alum, alcohol, and glycerin, possessing similar longevity to Ehrlich's hematoxylin.

Celestine Blue

An oxazine dye that forms an acid-resistant mordant complex with ferric salts, applied prior to alum hematoxylin staining to strengthen nuclear binding.

Iron Hematoxylins

Hematoxylins utilizing iron salts (such as ferric chloride or ferric ammonium sulfate) as both mordant and oxidizing agent to demonstrate a broader range of tissue structures.

Weigert’s Hematoxylin

An iron hematoxylin nuclear stain resistant to decolorization by subsequent acidic staining solutions, such as picric acid in van Gieson stain.

Heidenhain’s Hematoxylin

A cytological iron hematoxylin used regressively with ferric ammonium sulfate as a differentiator to demonstrate chromatin, chromosomes, mitochondria, muscle striations, and myelin.

Verhöeff’s Hematoxylin

An iron hematoxylin solution containing ferric chloride and Lugol's iodine, used specifically to stain elastic fibers black.

Loyez’s Hematoxylin

An iron hematoxylin using ferric ammonium sulfate as mordant and Weigert's differentiator to demonstrate myelin in paraffin, frozen, or nitrocellulose sections.

Phosphotungstic Acid Hematoxylin (PTAH)

A tungsten hematoxylin staining technique used primarily in CNS histology to demonstrate fibrin, muscle striations, cilia, neuroglia fibers, and myelin.

Molybdenum Hematoxylins

Rare hematoxylin solutions using molybdic acid as mordant to stain collagen, coarse reticulin, and argentaffin cell granules.

Lead Hematoxylin

A specialised hematoxylin formulation used to demonstrate granules in endocrine cells of the alimentary tract and locate gastrin-secreting cells.

Eosin Y

The most widely used water-soluble xanthine dye that serves as a counterstain for cytoplasm and connective tissue fibers in shades of pink, orange, and red.

Blueing

The step in H&E staining where sections treated with acid alcohol or hematoxylin turn blue upon treatment with an alkaline solution such as Scott's tap water substitute or ammonia water.

Ringing Media

Substances such as paraffin wax, cement, or varnish applied to coat the edges of a coverslip to prevent air bubbles from entering mounted slides.