Histopathology Flashcards
1
Q
What is histopathology?
A
Examination of tissues
2
Q
What is cytopathology?
A
Examination of individual cells
3
Q
What are the 3 types of tissue samples?
A
- Biopsies
- Resection specimens
- Frozen specimens
4
Q
What do histopathologists do?
A
Examine tissues
- Analyse biopsies, resection specimens, frozen specimens and post-mortems
5
Q
What do cytologists do?
A
Examine individual cells
6
Q
What are the 2 purposes of tissue sections?
A
- Diagnoses
- Determine efficacy of treatment
7
Q
What is a biopsy
A
Small section of tissue removed from patient
8
Q
How are biopsies taken? (5)
A
- Small section of tissue surgically removed
- Preserved in formalin
- Embedded in paraffin wax
- Microtome slices to thin sections (2-3 micrometres)
- Mounted on a slide —> further prep eg. staining —> analysed under microscope
9
Q
What solution is used to fix tissues during biopsy and why?
A
Formalin
10
Q
Why are biopsies embedded in paraffin wax?
A
Allow microtome to slice very thing sections
11
Q
What is used to obtain think slices from a biopsy?
A
Microtome
12
Q
What is a microtome?
A
Instrument used to cut extremely thin slices (biopsy)
13
Q
How can a biopsy be used in cancer diagnosis?
A
Diagnose type of cancer
14
Q
What is a resection specimen?
A
Tissue sample removed during a surgical procedure
15
Q
What are resections primarily used for?
A
See stage of disease
16
Q
What can resection specimens be donated to?
A
BioBanks —> research pathology
17
Q
What are frozen sections?
A
Fresh tissue frozen and analysed during a surgical procedure
18
Q
When are frozen sections analysed?
A
Whilst a surgical procedure is occurring
19
Q
How long do frozen sections take?
A
30 mins
20
Q
How are frozen sections taken? (3)
A
- Fresh tissue taken
- Cryostat freezes tissue
- Tissue cut, mounted and stained —> analysed under microscope
21
Q
What machine is used to obtain frozen sections?
A
Cryostat
22
Q
What are the 2 conditions of the tissue needed for a frozen section?
A
- Fresh
- No preservatives (no formalin used)
23
Q
How long do biopsies take?
A
2-3 days
24
Q
How long do resection sections take?
A
5-7 days
25
What is a tissue smear?
Thin layer of tissue/cells spread onto a microscope slide
26
What are the 2 modes of cytology analysis?
1. Smears
2. Fine needle aspirate
27
What is an aspirate?
Sample of tissue draw out of body using a needle
28
How are fine needle aspirates taken?
Thin, fine needle used to withdraw sample of cells/fluid a mass or lesion
29
What is the advantage of fine needle aspirates?
Can reach usually inaccessible tissues without surgery
- eg. Thyroid nodule
30
What is the disadvantage of fine needle aspirates?
Looks at isolated cells only ---> can't see tissue architecture
31
What proportion of pathological diagnoses test use antibody conjugation?
Over half (53/86)
32
Which method is most used for pathological diagnosis?
Conjugation of antibodies
33
Which 3 dsDNA producing diseases are diagnosed using antibodies and why?
1. SLE (lupus)
2. Sjogren's syndrome
3. Rheumatoid arthritis
34
What is immunohistochemistry?
Technique used to visualise and identify specific proteins using tagged antibodies (markers)
35
Where are antibody conjugates binded to?
Fc region (constant)
36
What are the 4 antibody conjugates?
1. Enzymes
2. Fluorescent probes
3. Magnetic beads
4. Drugs
37
What are 2 examples of enzyme conjugated antibodies?
1. Peroxidase
2. Alkaline phosphatase
38
Why do fluorescent probe conjugated antibodies allow for rapid analysis?
Immediately detected ---> don't need extra step
39
What is multiplexing?
Simultaneous analysis of multiple proteins using multiple different antibodies
40
When is multiplexing used?
When tissue sample is valuable/difficult to obtain ---> get out as much information from single sample as possible
41
When are magnetic beads used as antibody conjugates?
Cell type isolation (purification)
42
How do magnetic beads antibody conjugates allow for cell type isolation?
1. Magnetic bead surrounded by antibody
2. Specific cell type binds to antibodies
3. Magnet used to attract magnetic beads ---> takes antibodies and bound cells with it ---> only specific cells towards magnet
43
What is an example of a magnetic bead conjugated antibody?
Isolation of T cells from bone marrow using anti-CD3
44
Why may drugs be conjugated to antibodies?
Target specific tissues/sites of diease
45
What is an example of a drug conjugated antibody?
Kadcyla = anti-HER2 + emtansine
- Anti-HER2 ---> binds to HER2 receptors
- Emtansine ---> cytotoxic chemical (drugs)
- Used to treat HER2-positive breast cancer
46
What are the 2 types of antibody detection?
1. Direct
2. Indirect
47
What is direct antibody detection?
Detection of antibodies directly in a sample
- Primary antibody binds to antigen ---> detected
48
What is a primary antibody?
Antibody that directly binds to a specific antigen
49
What is indirect antibody detection?
Use of a secondary marked antibody to detect presence of primary antibody
- Primary antibody binds to antigen ---> secondary antibody added to bind to primary antibody ---> detected
50
What is a secondary antibody?
Antibody that binds to primary antibody constant region
51
What are 3 uses of manufactured antibodies
1. Blood group serology
2. Immunoassays
3. Immunodiagnosis
52
What are 3 examples of when antibodies are used for immunodiagnosis?
1. See presence of pathogen
2. See body's antibody levels ---> see if infected
3. Test for IgE presence ---> see if hypersensitivity reaction
53
What is the ELISA test?
Enzyme Linked ImmunoSorbent Assay
54
What are the 4 steps of the ELISA test?
1. Sample adhered to plastic plate
2. Probe with antibody specific to molecule of interest
3. If antibodies bind ---> enzyme conjugate colours solution
4. Standard curve used to determine concentration of molecule (colorimetry)
55
What is flow cytometry?
Cells with differently conjugated antibodies analysed via laser beam
56
What is the use of flow cytometry?
Immunophenotyping (analyse number of each immune cell present depending on differing surface proteins)
57
What are the ... steps of flow cytometry?
1. Antibodies attached to cells
2. Fluid containing antibody-labelled cells ---> single-file stream through laser
3. Light through cell ---> colour and scatter pattern analysed
58
What is identified via flow cytometry? (2)
1. Identity of cell surface molecules (that added antibody is bound to)
2. Cell size and granularity
---> Identity of cell
59
Which properties of the laser beam are used in flow cytometry analysis?
1. Colour
2. Scatter pattern
60
What are the 5 examples of antibodies used in flow cytometry and what do they detect?
1. anti-CD3+ ---> all T cells
2. anti-CD4+ ---> Th cells
3. anti-CD8+ ---> Tc cells
4. anti-CD19+ ---> B cells
5. anti-CD56+ ---> NK cells
61
How can T cells be detected in flow cytometry?
anti-CD3+
62
How are Th cells detected in flow cytometry?
anti-CD4+
63
How are cytotoxic T cells detected in flow cytometry?
anti-CD8+
64
How are B cells detected in flow cytometry?
anti-CD19+
65
How are NK cells detected in flow cytometry?
anti-CD56+
66
Which type of reaction is flow cytometry usually used to analyse?
Immune
