Exam #1: Medical Applications of Tissue Processing & Examination

Question 1

7 Steps of Tissue Preparation for Light Microscopy

Answer 1

1) Fixation
2) Dehydration
3) Clearing
4) Embedding
5) Sectioning
6) Mounting
7) Staining

Question 2

Fixation (Purpose & Reagent)

Answer 2

• Preserve normal tissue after death

- Formalin &Glutaraldehyde

Question 3

Dehydration (Purpose & Reagent)

Answer 3

• Remove water from tissue specimen

- Graded series of ethanol (50-100%)

Question 4

Clearing (Purpose & Reagent)

Answer 4

• Prepare the tissue for embedding

- Xylene

Question 5

Embedding (Purpose & Reagent)

Answer 5

• Infiltrate w/ Parafin so that it can be sectioned

Question 6

Sectioning (Purpose & Reagent)

Answer 6

• Tissue is cut into sections w/ microtome

Question 7

Mounting (Purpose & Reagent)

Answer 7

• Sections placed on glass slide

Question 8

Staining (Purpose & Reagent)

Answer 8

• Provides contrast to tissue structures for visualization

Question 9

Acid Dye

Answer 9

Net negative charge

Question 10

Basic Dye

Answer 10

Net positive charge

Question 11

Acidophilic

Answer 11

• Cellular structures w/ a net positive charge

- Have affinity for negatively charged dye

Question 12

Basophilic

Answer 12

• Cellular structures w/ a net negative charge

- Have affinity for positively charged dye

Question 13

Metachromasia

Answer 13

Phenomenon in which a stain imparts different colors to a tissue in a density dependent manner

Question 14

Hematoxlyin (1. What does it stain? 2. What color? 3. Clinical Application?)

Answer 14

• RNA, DNA, ribosome, & ER affinity
• Stains Blue
• Basic
• Coagulative Necrosis

Question 15

Eosin (1. What does it stain? 2. What color? 3. Clinical Application?)

Answer 15

• Secretory Vesicles, sER, Lysosomes, Mitochondria, Type I Collagen
• Stains Pink
• Acid
• Coagulative Necrosis

Question 16

Feulgen Reaction (1. What does it stain? 2. What color? 3. Clinical Application?)

Answer 16

• DNA (Both Nuclear & Mitochondrial)
• Stains Magenta

-Nuclear changes in Cancer

Question 17

Mallory Triple (1. What does it stain? 2. What color? 3. Clinical Application?)

Answer 17

Dye Cocktail that stains a spectrum of colors:

• Nuclei= Red
• Muscle= Red to Orange
• Collagen= Blue
• Hyaline Cartilage= Blue

-Fibrosis

Question 18

Periodic Acid Schiff (PAS) Reaction (1. What does it stain? 2. What color? 3. Clinical Application?)

Answer 18

• Carbohydrates
• Magenta
• Thickened basement membranes in kidney disease
• Glycogen Storage Disease (Liver)
• Alpha 1-Antitrypsin Disease (Emphysema)

Question 19

Osmic Acid (1. What does it stain? 2. What color? 3. Clinical Application?)

Answer 19

• Lipids

- Black

Question 20

Verhoeff (1. What does it stain? 2. What color? 3. Clinical Application?)

Answer 20

• Elastic Fibers
• Black
• Elastic Fibers in Marfan Syndrome

Question 21

Silver Methods (1. What does it stain? 2. What color? 3. Clinical Application?)

Answer 21

• Intermediate Filaments of Nerve Cells, Glial Cells, Reticular Fibers
• Black

Question 22

Trypan Blue (1. What does it stain? 2. What color? 3. Clinical Application?)

Answer 22

• Stains Macrophages in “Vital Tissue”

- Blue

Question 23

Prussian Blue (1. What does it stain? 2. What color? 3. Clinical Application?)

Answer 23

• Hemosiderin (Ferric Iron)
• Blue

-Excessive iron in hemochromatosis

Question 24

Nissil (1. What does it stain? 2. What color? 3. Clinical Application?)

Answer 24

• Ribosomes

- Blue

Question 25

Iron Hematoxylin (1. What does it stain? 2. What color? 3. Clinical Application?)

Answer 25

- Nuclear Elements, Chromosomes, Mitochondria, Centrioles & Muscle Striation - Dark blue to black

Question 26

Congo Red

Answer 26

Amyloid Deposits (e.g. Alzheimer's Disease)

Question 27

Frozen Tissue Section

Answer 27

- Preparation method when tissue examination is urgent | - Results in thicker slices with less detail

Question 28

Immunocytochemistry

Answer 28

- Technique that uses tagged antibody as a marker directed to a specific antigen - Direct & Indirect

Question 29

Direct Immunocytochemistry

Answer 29

- Less sensitive w/ fewer antibodies | - Marker associated w/ antibody

Question 30

Indirect Immunocytochemistry

Answer 30

- More sensitive w/ more antibodies that amplify the signal | - Marker associated with antibody to antigen/antibody complex

Question 31

Clinical Utility of Immunocytochemistry

Answer 31

- Categorization of Tumor Origin e.g. Cytokeratins (Epithelial) & D2-40 (Lymph) - Breast Cancer e.g. Estrogen Receptor, HER2/neu, & Carinoembryonic Antigen

Question 32

In situ hybridization

Answer 32

- Uses complementary nucleic acid probes to specifically identify a nuclei acid sequence - When probe has a fluorescent maker, called FISH

Question 33

Clinical Utility of In situ hybridizatyion

Answer 33

- Id. cell infected w/ virus e.g. HPV - Id. specific genes on a chromosome e.g. BRCA1 & 2 - Detection of gene amplification e.g. Myc & HER2/neu