Week 5- Histopathology Flashcards
What does a histopathologist do?
Examines tissue specimens, analyzing the architecture of the tissue and drawing conclusions about what this tells us about the condition
What does a cytopathologist do?
Examines cells and makes expert diagnosis
What is the time frame for a biopsy result?
2/3 days
What is the time frame for a resection specimen result?
5/7 days
What is the time frame for a frozen section result?
30 mins
How are biopsies prepared?
Tissue is embedded in formaldehyde to preserve it by cross linking proteins, it can then be cut into thin (2-3 micrometers) slices to be examined by a microtome. Often the tissue may be stained
How are resection specimens prepared? What are they used for?
Sample taken from tissue removed during surgery and can indicate stage of disease eg has cancer spread to nodes, has all cancerous tissue been removed, is chemotherapy required?
How are frozen sections prepared? What are they used for?
Tissue is taken during the surgery and analysis is quick as it helps inform the course of the surgery. No formaldehyde is used and the tissue is frozen using a cryostat. It answers questions like is this tissue cancerous? Has all cancerous tissue been removed?
What test do cytopathologists mainly use to analyse cells?
Fine needle aspiration
How are fine needle aspirations carried out and why are they useful?
A long thin needle is used to take a sample from a lesion without the need for a full biopsy. Is useful as it can reach relatively remote tissue but as only cells are visible, conclusions about the tissue cannot be made
How are antibodies used as diagnostic tools?
Levels of circulating antibody can be good indicators to certain conditions, antibodies are also easy to produce and when injected can attach to specific cells which is useful in a diagnostic aspect. They can detect carbs, proteins and lipids either via direct binding or via a second antibody conjugated w a fluorescent probe/enzyme
What conditions may antibodies with double stranded DNA indicate?
Systemic lupus erythrematosus
Rheumatoid arthritis
What does ELISA stand for and what is it?
Enzyme linked immunosorbent assay
A clinical sample is adhered to a plate
An antibody labelled with a marker (fluorescent probe/color etc) that binds to this sample is added
The relative absorbance is measured and can indicate the concertation of the molecule in question in the clinical sample
How is flow cytometry carried out and when is it used?
It is used when trying to understand the nature of an inflammatory response
CD8/CD4 + cells etc are labelled with differently conjugated antibodies and put through a laser beam. The color and side scatter can denote the identity of the cells (changes due to granularity and side scatter)
