Histopathology Flashcards
What is the difference between histopathologists and cytopathologists
Histopathologists look at the architectural structure of tissues, where cytopathologists look at the morphology of cells
What substances are needed for analysis of biopsies
Formalin is used to preserve tissues, paraffin is used to be able to cut tissue into thin slices, a stain to elucidate the details of interest
Which instrument cuts the biopsies in thin slides
Microtome, a microscopically cutting device
What is the Ziehl-Nielsen stain used for in histopathology
The Ziehl-Nielsen stain is used to stain acid-fast bacteria
Which stain is used in histopathology to identify leukocytes in tissues
Haematoxylin and eosin stain that elucidates the nuclei and the cytoplasm in leukocytes
What is resection specimen
A tissue that is removed during surgery and then used for diagnosis in histopathology, mainly for stage of cancer
What instrument is used to make frozen specimens and when is this used
Cryostat, used by pathologist during real time surgery to look at tissues to give diagnosis that guides surgeon in his decisions
How long does it take for frozen specimens, biopsies and resection specimens to get to clinician
Frozen specimens approximately 30 minutes, biopsies 2-3 days and resection specimens 5-7 days
What are fine needle aspirates used for
To take cells for diagnosis at locations in the body that are hard to get access to without need for surgery
Which substances are used in immunohistochemistry
Antibodies that bind to specific molecule of interest, either conjugated to enzyme or fluorophore so to stain place of binding
What region of antibodies is conjugate attached to
Fc-region of antibody
Which types of conjugations can be attached to antibodies
Enzymes, magnetic beads, fluorophores/fluorescent probes and drugs
Which kind of conjugation does the CD31 cancer immunohistochemistry staining use
Enzymatic conjugation to antibody
What is the advantage of fluorescent probes
This form of staining allows very rapid measurement of molecules on cells because colouring is already there
What is multiplexing and why is it used
Attaching multiple different antibodies with different fluorescent probes to different molecules on cells, because some clinical samples are very precious and small volume
What is magnetic bead conjugation used for
To purify one cell type from tissue by attaching antibody to specific cell marker
What cytotoxic drug is added to Kadcyla drug for breast cancer and what receptor does it bind to
The chemical cytotoxic drug emtansine is bound to anti-HER2-antibody that specifically binds to the HER2-receptor on breast cancer cells
What is the difference between direct and indirect detection in antibody diagnostics
In direct detection, one antibody type is used to detect certain molecules in sample. In indirect detection, a secondary antibody is used that binds to the primary antibody and this secondary antibody can be detected.
What are antibody diagnostics used for in blood transfusions
Antibody diagnostics are used in blood transfusion to find out blood group of recipient and present antibodies in blood plasma and so linking it to the right type blood transfusion
What is an immunoassay
Detection of substances in the blood plasma by antibodies such as detection of hormones or specific antibodies
In what diseases might immunodiagnosis be useful (three examples)
In infectious diseases where body has created antibodies that can be detected and indicate infection, in myelomas where antibodies are formed and in allergies where there is more circulating IgE than normal
What does ELISA stand for and what does it detect
Enzyme-linked immunosorbent assay, it can detect molecules that are adhered to sample surface, typically plasma molecules
How does it detect different concentrations of antigens and what is used as reference
The antibodies are conjugated to enzymes that turn colourless substrate into coloured product and this absorbance is measured and compared against standard curve to allow for quantitive analysis
What is flow cytometry and how does the procedure work
Flow cytometry is a detection method to detect specific cell types that are bound to marker antibodies with fluorescent probes that are then moved in a single past a laser and every probe reflects light differently and this used to gain information on cell type, volume and granulation
Which cells are often analysed by flow cytometry
Lymphocytes
What different information can be determined about cells in flow cytometer
Different cell type, the size of the cell and the granularity of the cell
Which antibodies are used for detecting T-cells (cytotoxic and helper), B-cells and NK cells
Anti-CD3 for all T cells, anti-CD4 for Th-cells, anti-CD8 for Tc-cells, anti-CD19 for B cells, anti-CD56 for NK cells
How are cells moved through flow cytometer
They move from sample past laser beams in a single stream of cells
What does the oil red O stain elucidate
Stains lipids in tissues
What does Congo red stain elucidate
ECM components such as elastin and collagen
