Pathology Recall: Pathology Diagnostic Techniques

Front 1

Pathologic tissues are sent to the lab in what two forms?

Back 1

Gross
Cytologic

Front 2

What possible, how should specimens be transported?

Back 2

Fresh tissue in saline should be rapidly transported

Front 3

Name the 5 common techniques used to analyze tissues.

Back 3

1) Cytology
2) Immunohistochemistry
3) Flow cytometry for DNA analysis
4) Electron microscopy
5) Hybridization procedures for DNA analysis

Front 4

What is cytology?

Back 4

The use of various cells scraped form the lining of orifices or obtained by fine needle aspiration to study disease processes.

Front 5

What imaging techniques are often used for needle quided biopsies?

Back 5

CT
US

Front 6

How invasive is cytology?

Back 6

Minimally invasive. Cells can be taken from any secretions, brushing of lesions. If FNA is required, an extremely thin needle may be used.

Front 7

Is cytology helpful in diagnosing cancer?

Back 7

YES
It is necessary to visualize changes in neoplastic cells.

Front 8

Name 3 common uses of FNA.

Back 8

Obtaining diagnostic tissue samples of:
1) Breast masses
2) Hepatic nodules
3) Lung lesions

Front 9

What is IHC?

Back 9

The use of antibodies to tissue markers (antigens) for diagnostic purposes.

Front 10

What types of antibodies can be used?

Back 10

Polyclonal antibodies
Monoclonal antibodies

Front 11

What are two methods for detection of polyclonal and monoclonal antibody-antigen interactions?

Back 11

Fluorescent probe (immunofluorescence)
An enzymatic system such as peroxidase (immunoperoxidase)

Front 12

How are these tissues stored?

Back 12

Frozen tissue
Paraffin-embeded tissue

Front 13

Immunofluorescence is commonly used with what 3 tissues?

Back 13

Skin
Kidney
Lung

Front 14

What dye is most frequently used with Immunofluorescence?

Back 14

Fluorescein isothiocyanate

Front 15

What five uses does immunofluorescence have?

Back 15

1) Detction of autoantibodies
Localization of tissue antigens
2) Identification of microorganisms in tissues
4) Identification of immune complexes deposits
5) Identify complement proteins

Front 16

Describe the action of immunoperoxidase.

Back 16

It catalyzes a substrate, making a product at the site of the antigen.

Front 17

How is Immunoperoxidase activated?

Back 17

A secondary antibody, which is conjugated to peroxidase, attaches to the primary antibody-antigen complex.

Front 18

What other enzyme is often used to catalyze a substrate?

Back 18

Alkaline phosphatase.

Front 19

What are eight common uses for alkaline phosphatase?

Back 19

1) ID the cells of origin, oncofetal antigens, tissue specific markers, or loss of an antigen in neoplasm.
2) Detecting hormones or hormone receptors
3) Localizing enzymes
4) Differentiating types of lymphomas
5) Detecting amounts of a type of cell
6) Finding autoantibodies
7) ID-ing viral antigens
8) ID-ing microorganisms

Front 20

What are the advantages of alkaline phosphatase over IF?

Back 20

1) Higher sensitivity
2) The preparations are permanent
3) Paraffin-embedded tissues are better for visualizing cell details
4) Lesser amounts of antibody are used because of higher dilution rates.

Front 21

What is flow cytometry?

Back 21

Analysis of cell populations by treating cells with specific antibodies and passed through a laser. The light is then analyzed to give properties of the cells.

Front 22

What is flow cytometry used for?

Back 22

To determine the DNA ploidy of neoplastic tissues.

Front 23

Why is flow cytometry method for determining neoplastic tissue important?

Back 23

The ploidy of a tumor often predicts the nature of a tumor.

Front 24

Reactive and benign lesions are always what ploidy?

Back 24

Diploid
However, not all diploids neoplasms are benign.

Front 25

What is the usual ploidy of neoplastic and malignant lesions?

Back 25

Aneuploid

Front 26

What types of tissue can be used?

Back 26

Fresh tissue
Formalin-fixed tissue

Front 27

What is the first step after a sample has been obtained?

Back 27

Cell nuclei are extracted from a tissue sample.

Front 28

What is done with nuclei in flow cytometry?

Back 28

They are stained and analyzed in a flow cytometer.

Front 29

What is the next step in flow cytometry after the nuclie are stained and analyzed?

Back 29

The amount of emitted light of a specified wavelength determines the amount of DNA per cell.

Front 30

What an be constructed from the date from flow cytometry to determine the number of cells in each phase of the cell cycle and the ploidy of the cells.

Back 30

DNA histogram

Front 31

Why is EM important?

Back 31

It allows the study of tissues at the ultrastructural level.

Front 32

What is EM used for?

Back 32

1) Evaluation of rare infections
2) Diagnosis of immune compex disease.
3) Diagnosis of neoplasms by showing alterations in cellular structure.

Front 33

What are several disadvantages of EM?

Back 33

1) Expense
2) Special tissue preparations are necessary.
3) Tests often require several days
4) Sampling error is high because it only looks at a minute portion of the sample.

Front 34

What can hybridization procedures do?

Back 34

Isolate and identify DNA fragments.

Front 35

What are hybridization procedures used for?

Back 35

1) Identification of microbes using DNA probes
2) Gene studies of inherited conditions, such as sickle cell anemia
3) Determination of compatibility of gene alleles for translant tissue typing.
4) Identification of lymphoproliferative disorders by using gene arrangements for B and T cells disorders.

Front 36

Name the common types of hybridization procedures.

Back 36

Southern blot tests
DNA gene rearrangement assays
In situ hybridization
In situ hybridization-polymerase chain reaction.

Front 37

How are DNA fragments from tissue abstracts separated in Southern blot tests?

Back 37

Electrophoresis

Front 38

What does a probe combine with in Southern blot tests?

Back 38

A known DNA or RNA sequence
A labeled radioisotope

Front 39

What does a probe combine with in Southern blot tests?

Back 39

The complementary sequences on the blot

Front 40

How are the unknown nucleic acid sequence indentified in Southern blot tests?

Back 40

Autoradiography

Front 41

What are DNA gene rearrangement assays for?

Back 41

For detection of lymphomas and leukemias.

Front 42

How do DNA gene rearrangement assays detect lymphomas and leukemias?

Back 42

In a technique similar to in situ hybridization, in which probes are hybridized to fresh tissues, lymphomas and leukemias show gene arrangements while nonmalignant disorders will show a germline (nonrearranged) immunoglobulin or t-receptor genes.

Front 43

Why is In situ hypridizatin (ISH) important?

Back 43

It allows examination of a tissue section, as opposed to a tissue extract. The exact location of the probe in the tissue can be found.

Front 44

What is often detected in In situ hypridizatin (ISH)?

Back 44

Viral infections, because multiple copies of DNA per cell are present.

Front 45

What is often difficult to detect with In situ hypridizatin (ISH) because multiple copies are not always present?

Back 45

Oncogenes of tumors

Front 46

How can In situ hypridizatin (ISH) be changed to detect oncogenes of tumors?

Back 46

In situ hybridization-polymerase chain reaction.

Front 47

How is ISH-PCR different from ISH?

Back 47

Small pieces of DNA or RNA which cannot be detected by ISH can be amplified using specific probes, allowing detection.

Front 48

What technique is best used to differentiate Prostate CA from gastric CA?

Back 48

IHC

Front 49

What technique is best used to differentiate Lymphoma from carcinoma?

Back 49

IHC or electron microscopy

Front 50

What technique is best used to differentiate adenocarcinoma from mesothelioma?

Back 50

IHC or electron microscopy