CHAPTER 17 STAINS AND STAINING SOLUTIONS

Question 1

Biological stains or coloring substances are prepared from dyes which may generally be divided into two categories:

Answer 1

1. Natural dyes
2. Synthetic (artificial) dyes

Question 2

• e.g., cochineal dyes, logwood dyes, and vegetable extracts

Answer 2

1. Natural dyes

Question 3

• e.g., aniline or coal tar dyes

Answer 3

2. Synthetic (artificial) dyes

Question 4

Natural dyes are those obtained from plants and animals, previously utilized for dyeing of wool and cotton. Among the most common natural dyes available are:

Answer 4

1. Hematoxylin
2. Cochineal dyes and its derivatives
3. Orcein
4. Saffron

Question 5

Hematoxylin is a natural dye derived by extraction from the core or the heartwood of a Mexican tree known as

Answer 5

“Hematoxylin Campechianum”.

Question 6

It is by far the most valuable staining reagent used by the cytologist due to its powerful nuclear and chromatin staining capacity, and its striking polychrome properties which may be produced with proper differentiation.

Answer 6

HEMATOXYLIN

Question 7

It may be used after almost any fixative and is a permanent stain.

Answer 7

HEMATOXYLIN

Question 8

itself is not a true basic dye.

Answer 8

HEMATOXYLIN

Question 9

The active coloring agent is hematin, which is formed by the oxidation of hematoxylin, a process known as

Answer 9

“ripening.”

Question 10

are substances that combine with the tissue and the staining solution, forming a “bridge” that allows staining reaction to take place.

Answer 10

Mordants

Question 11

are recommended for progressive staining of tissues, and are usually counterstained with Eosin, Congo Red and Safranin.

Answer 11

Alum hematoxylin stains

Question 12

Both the Ehrlich’s solution and the Harris’ solution contain

Answer 12

Alum Hematoxylin.

Question 13

Rapid ripening of Ehrlich’s reagent, however, is brought about by the addition of [?]; while Harris solution is ripened with [?].

Answer 13

Sodium Iodate

Mercuric Chloride

Question 14

compounds are used only for differential or regressive staining, using Acid-Alcohol as a differentiating agent.

Answer 14

Iron hematoxylin

Question 15

An example of an Iron Hematoxylin compound is Weigert’s Stain using

Answer 15

Iron (Ferric) Chloride.

Question 16

solutions are utilized for the study of spermatogenesis.

Answer 16

Copper hematoxylin

Question 17

is used frequently in histology to examine thin sections of tissue.

Answer 17

Hematoxylin and eosin (H&E) staining protocol

Question 18

Hematoxylin stains cell nuclei [?], while eosin stains cytoplasm, connective tissue and other extracellular substances [?]. Eosin is strongly absorbed by red blood cells, coloring them [?].

Answer 18

blue

pink or red

bright red

Question 19

is a vegetable dye extracted from certain lichens which are softener.

Answer 19

Orcein

Question 20

Trichloracetic acid, picric acid and chromium-fixed tissues usually take in [?] more readily.

Answer 20

acidic dyes

Question 21

Basic cell structures (collagen, eosinophilic granules of leukocytes, etc.) have an affinity for the acid dye ions and are regarded as

Answer 21

acidophilic.

Question 22

• where the active coloring substance is found in a basic component that combines with the acid radical (usually taken from sulfuric, acetic or hydrochloric acid).

Answer 22

Basic Dyes