Histopathology Flashcards

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1
Q

What does a histopathologist do?

A

Deals with tissues, examines the sections, and notes the architecture of the tissue and identify what it tells us about a particular condition

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2
Q

What does a cytopathologist do?

A

Deals with cells, takes them from the patient and prepares them for examination and then delivers their expert diagnosis on the cell sample.

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3
Q

What are the four tissue samples a histopathologist will work with?

A
  1. Biopsies
  2. Resection specimens
  3. Frozen Sections
  4. Post-Mortems
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4
Q

What are real-time examinations used for?

A

for surgical processes

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5
Q

What are biopsies?

A

Small sections of tissues removed from a patient

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6
Q

What solution are biopsy tissues placed in for preservation?

A

Formalin

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7
Q

How are biopsy samples preserved?

A

The formalin they are preserved in cross links the proteins and fixes the tissue

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8
Q

What are biopsy tissues embedded in to allow very thin sections to be cut?

A

Paraffin wax (2-3 micrometers thick)

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9
Q

What cuts the biopsy tissue into very small sections?

A

Microtome

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10
Q

What stain is used to identify the nuclei and cytoplasmic granules of leukocytes within tissues?

A

Haemotoxylin and Eosin (H&E)

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11
Q

What is used to stain acid fast bacteria?

A

Ziehl-Neelsen stain

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12
Q

What stain is used to aid the diagnosis of tuberculosis infection?

A

Ziehl-Neelsen

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13
Q

How long does the results of a biopsy take to reach the clinician?

A

2-3 Days

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14
Q

How long does it take for the results of a frozen section to reach the clinician?

A

30 Minutes

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15
Q

How long does it take for results of a resection specimen to reach the clinician?

A

5-7 days

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16
Q

What are resection specimens?

A

specimens are taken from tissue that has been removed as part of a surgical procedure and can be processed as for a biopsy.

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17
Q

What are resection specimens primarily used to do?

A

Look at the stage of disease

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18
Q

Why may tissue samples from resection specimens be donated to biobanks?

A

They may be used to inform genomic studies of the disease process

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19
Q

What is a frozen section?

A

A sample taken during a surgical procedure and examined by pathologists in real time

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20
Q

What is used to freeze the tissue?

A

Cryostat (a machine)

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21
Q

What happens to the frozen tissue from the frozen section?

A

it is frozen, cut, mounted on slides and stained as for biopsies

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22
Q

What are the requirements for tissue samples to be frozen?

A

Fresh and free of preservatives like formalin

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23
Q

What is a fine needle aspirate?

A

When a fine needle is inserted into a lesion and used to aspirate the cells out the lesion for anaylsis

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24
Q

Why is fine needle aspiration useful?

A

The needle can easily penetrate relatively inaccessible tissues without the need for surgery
e.g., thyroid nodule

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25
Q

What is the downside of fine needle aspiration?

A

the cytopathologist is only looking at cells and is unable to comment upon the likely architecture of the tissue.

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26
Q

Give an example of when both histopathology and cytopathology are used?

A

In the diagnosis of reactive lymphadenopathy

fine needle aspirate of enlarged lymph nodes and skin biopsy

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27
Q

What does Oil Red O stain?

A

Lipids

28
Q

What does congo red stain?

A

ECM components like elastin and collagen

29
Q

Which molecules are conjugated to the Fc region of an antibody for their use in flow cytometry?

A

Fluorophores

30
Q

When requesting a test from the pathology lab to aid with a diagnosis, it is important to appreciate just how long the various procedures take. Put the following pathology lab tests in order of the time taken to get the result back to the clinician (quickest to slowest).



  1. Resection tissue
  2. Biopsy
  3. Frozen section
A

3 - 2 - 1

31
Q

The immunological lab offers how many different tests, and of those how many are used to detect the level of specific antibodies circulating in patients?

A

86
53

32
Q

What are examples of the antibody tests offered by the immunological lab?

A

dsDNA

systemic lupus erythematosus (SLE)

Sjogren syndrome

Rheumatoid arthritis

33
Q

What is Kaposi’s sarcoma?

A

Rare cancer and is often indicative of immunodeficiency (AIDS)

Spindly resembling cells evidently penetrates the collagen fibres

34
Q

What four forms can antibody conjugations come in?

A
  1. Enzymes
  2. Fluorescent probes
  3. Magnetic beads
  4. Drugs
35
Q

What 2 types of detection can antibodies be used for?

A

Indirect - antibody with marker binds to another antibody which binds to antigen

Direct - antibody with marker binds to antigen

36
Q

What are conjugations?

A

Attachments to the Fc region of the antibody

37
Q

What are two examples of enzyme attachments?

A

Peroxidase and alkaline phosphatase

38
Q

When may enzyme attachments be used clinical?

A

The detection of oestrogen receptors on breast cancer tissue receptors

39
Q

What is multiplexing and what does it allow?

A

When several antibodies with different fluorescence are used, allows the measurements of several molecules in a single clinical sample

40
Q

What part of the antibody are conjugates attached to?

A

The Fc region

41
Q

How does enzyme conjugation work?

A

Antibody binds to antigen, and colourless substrate is added, the colourful product can be detected wherever the immune complex is (formed)

42
Q

Why do fluorescent probes allow for the rapid measurement of the levels of molecules within a sample?

A

because the colour is already there and unlike enzyme conjugation does not need to be formed

43
Q

Which is a good choice for an antibody conjugate when you have a small sample?

A

Fluorscent probes as you can performe multiplexing

44
Q

What can magnetic beads be used for?

A

The purification of cell types

45
Q

Give an example of how magnetic beads are used as a clinical conjugate?

A

deplete the bone marrow of T cells before bone marrow graft

46
Q

What can drugs as an antibody conjugate be used to do?

A

Directly deliver the drugs to the cells that are malfunctioning

47
Q

Describe an example of the clinical use of drugs as an antibody conjugate?

A

Kadcyla, anti-HER antibody - used in the treatment of breast cancer as HER2 is over-expressed in over 30% of breast cancers
It is linked to the cytotoxic chemical emtansine

48
Q

What makes antibodies useful as a diagnostic tool?

A

The unique specificity of the antibodies

49
Q

What other molecules can antibodies detect?

A

Proteins, carbohydrates and lipids

50
Q

Describe how indirect detection of antibodies works?

A

The antibody with the antigen bound to it is detected by a secondary antibody which is conjugated with an enzyme of fluorescent probe

51
Q

What can manufactured antibodies be used for?

A

Blood group serology
Immunoassays
Immunidiagnosis

52
Q

What can immunoassays be used for?

A

Detection of hormones or circulating antibodies/antigens

53
Q

What can be detected via immunodiagnosis using manufactured antibodies?

A

infectious diseases
antibody levels
IgE antibodies suggestive of allergic phenotype

Infectious diseases due to presence of anti-disease antibodies like HIV

54
Q

What is immune complex glomerulonephritis?

A

Disease caused by the presence of IgG-antigen immune complexes and Complement C3 from kidney biopsy

55
Q

What does flow cytometry notably allow the detection of?

A

Lymphocyte subpopulations

56
Q

How does flow cytometry work?

A
  1. Cells labelled with differently conjugated antibodies
  2. These cells then run as a stream of single cells through laser beams
  3. The colour of the light emitted and the scatterpatterns of the laser beam can denote the identify of the cell surface molecules expressed and the size and granularity of the cells and therefore the type and of cell
57
Q

Why is flow cytometry highly informative to?

A

The nature of a particular inflammatory reaction, as the tagged antibodies allow the detection of specific white blood cells like CD4 helper cells etc

58
Q

Anti CD3+ antibodies are used to detect what cell?

A

T cell - pan T cell marker

59
Q

Anti CD4+ antibodies are used to detect what cell?

A

T helper cells

60
Q

Anti CD8+ antibodies are used to detect what cell?

A

Cytotoxic T cells

61
Q

Anti CD19+ antibodies are used to detect what cell?

A

B cells

62
Q

Anti CD56+ antibodies are used to detect what cell?

A

NK cells

63
Q

What does ELISA mean?

A

Enzyme Linked ImmunoSorbent Assay

64
Q

What is the purpose of ELISA?

A

Used to determine the precise concentrations of molecules in a sample

65
Q

How does ELISA work?

A
  • Clinical samples (e.g. adheres to a plastic plate)
  • Probe with specific antibody raised against the molecule of interest.
  • Enzyme conjugation generates a coloured product.
  • Wash away excess, unbound antibody
  • Reference to standard curve (absorbance of light by coloured product) , determine precise concentrations of the molecule in the sample.