Staining of Carbohydrates

Question 1

Carbohydrates are the main source of _____ in the body.

Answer 1

energy

Question 2

Carbohydrates are mobilized in the form of
______________(glucose) and stored in the form
of _______________, either in pure form (glycogen),
or bound to other substances (mucin).

Answer 2

monosaccharides & polysaccharides

Question 3

It is made up of polysaccharides of glucose

Answer 3

Glycogen

Question 4

It is made up of hexosamines (neutral
mucopolysaccharides) or mucus that is
secreted by the goblet cells of intestinal
mucosa, respiratory lining cells and certain
glands

Answer 4

Mucin

Question 5

They are both stained by the Periodic Acid-Schiff (PAS) technique

Answer 5

Glycogen & Mucin

Question 6

It is a histochemical stain that will demonstrate carbohydrates and other
substances in the tissue.

Answer 6

Periodic Acid Schiff

Question 7

PAS technique uses periodic acid to specifically
oxidize the __________.

Answer 7

1,2 glycol group of polysaccharides

Question 8

______ that ar required for the coloration of Schiff’s reagent thereby producing a ____________ or ________.

Answer 8

Aldehyde, red magenta or purple-pink color.

Question 9

PAS is the only method in for carbohydrates

Answer 9

False

Question 10

PAS is not a method for carbohydrates in general but only for those which contain ______

Answer 10

1,2 glycols or closely related structures

Question 11

The treatment must be able to
produce an _______ on the carbohydrate
component.

Answer 11

Aldehyde

Question 12

The intensity of PAS reaction is proportional to the __________________ present in the reacting substance.

Answer 12

content of sugars

Question 13

In order to have a PAS-positive staining reaction,
oxidation must occur to produce _______.

Answer 13

aldehyde

Question 14

What happens when the oxidation continue beyond the aldehyde stage?

Answer 14

Result will be negative

Question 15

_________ is not the only oxidizing agent that has
been recommended for the oxidation of carbohydrates although it is certainly the most used and arguably
the most effective.

Answer 15

Periodic Acid

Question 16

Periodic acid is generally applied to the sections as a _________________________________.

Answer 16

0.5 to 1.0% aqueous solution for 2 to 20 (average 5) minutes at room temperature.

Question 17

Oxidation beyond _______ increases __________staining-probably due to
acidification of sulfhydryl groups into sulfonic
acid.

Answer 17

10 mins, basophilic methylene blue

Question 18

A temperature above 25°C which markedly accelerates the reaction, causing oxidation not only of aldehydes but also of other groups,

Answer 18

e.g., sulfhydryl and disulfide.

Question 19

Solution must be discarded if it turns _____ in color.

Answer 19

brown

Question 20

Most fixatives can be used with this staining technique, except those that contain

Answer 20

osmic acid, chromates and permanganates.

Question 21

Routine fixation and decalcification of bone will cause considerable ____ of PAS positivity.

Answer 21

loss

Question 22

PAS STAIN CAN BE USED TO DEMONSTRATE THE
FOLLOWING SUBSTANCES

Answer 22

Polysaccharides
Neutral mucus substances
Tissue basement membrane
Fungal organisms

Question 23

The main polysaccharide identified through histology staining is glycogen, which is present
in numerous tissues, including skeletal muscle, cardiac muscle, liver, and kidney.

Answer 23

polysaccharides

Question 24

PAS is also commonly used to stain and identify glycoproteins, glycolipids, and neutral mucins, which are produced by epithelial cells in different organs

Answer 24

Neutral mucus substances

Question 25

These PAS-positive thin layers of reticular connective tissue anchor and support epithelium and endothelium to underlying connective tissue.

Answer 25

Tissue basement membrane

Question 26

The cell walls of some living fungal organisms contain high levels of carbohydrate, and also stain positive with PAS.

Answer 26

Fungal organisms

Question 27

The reactivity of the PAS technique is based on the structure of the __________ units.

Answer 27

monosaccharide

Question 28

The stain involves periodic acid acting as an agent to oxidize the carbon-to-carbon bonds between ________________________________

Answer 28

two adjacent hydroxyl groups.

Question 29

The basic fuchsin in the mixture reacts with newly formed aldehyde groups in the tissue and produces a _________ color when the section is rinsed in water.

Answer 29

bright magenta

Question 30

Hematoxylin is typically used as a ________ to visualize other tissue elements.

Answer 30

counter stain

Question 31

___________ may also be used to assist in the diagnosis of glycogen storage diseases.

Answer 31

Diastase (alpha-amylase) digestion

Question 32

PAs sh the diagnosis stain can help with the diagnosis of the following:

Answer 32

Glycogen storage disease Tumors Fungal infection Basement membrane

Question 33

PAS is often routinely used in the clinic to demonstrate glycogen accumulation in biopsies of these tissues.

Answer 33

Glycogen storage diseases

Question 34

Glycogen granules can also be present in some tumors including some of those that arise in tissues such as the pancreas, lung, and bladder

Answer 34

Tumors

Question 35

PAS can be used to visualize some fungal organisms in tissue sections.

Answer 35

Fungal infection

Question 36

PAS can be used to highlight abnormal basement membrane abnormalities such as in glomerular diseases

Answer 36

Basement membrane

Question 37

The essential component of Schiff reagent is basic fuchsin, which is a mixture of three dyes:

Answer 37

Rosanilin Pararosanilin Magenta II

Question 38

Sulfur dioxide converts the magenta-colored basic fuchsin into __________

Answer 38

colorless leukofucshin.

Question 39

A good quality Schiff's reagent should be made from _________ rather than basic fuchsin.

Answer 39

pararosaniline

Question 40

Beware of ________ which give a brown solution when first made.

Answer 40

dye batches

Question 41

The most common application of Schiff reagent is _________

Answer 41

Periodic Acid Schiff

Question 42

This is a technique for the demonstration of carbohydrates in tissue sections

Answer 42

PAS

Question 43

The purpose of the periodic acid is to ______ some of the tissue carbohydrates

Answer 43

oxidize

Question 44

This produces aldehyde groups, which can then condense with Schiff's reagent forming a __________ and demonstrating the tissue component to which the carbohydrate is attached.

Answer 44

bright red coloration

Question 45

Schiff reagent is stored in the refrigerator so it is important to allow the reagent to come to room temperature before use.

Answer 45

➜ Failure to do so may result in weak staining. ➜ It is also important to store Schiff reagent in a tightly closed container when not in use so that the solution remains potent and stable

Question 46

Schiff reagent can be prepared in different ways:

Answer 46

1. By using thionyl chloride to release sulfur dioxide 2. By adding sodium or potassium metabisulfite 3. By using sulfur dioxide gas

Question 47

Two kinds of Schiff reagent

Answer 47

Barger and de lamater method De Tomasi-Coleman Method

Question 48

Both Schiff reagent are stable and may last up to ___ months

Answer 48

6

Question 49

The reagent should be discarded when it begins to form a _____

Answer 49

color