Histopathology Flashcards
What are resections?
Taken from tissue removed as part of a surgical procedure and processed for biopsy. Or donated for further study
What is a histopathologist?
deals with tissues, examines sections, what it tells about a condition
What is fine needle aspirates?
get into a lesion and aspirate cells, analysed for smear. assess without surgery.
What are frozen sections?
Examined by pathologists in real time as px is operated on.
cyrostat freezes it, it is cut and mounted. stained.
(need to be fresh tissues and free of preservatives like formalin)
Why may cells burst during preservation?
Under 15 degrees ATPase pump stops functioning and without circulation and hence oxygen there is little ATP to pump out Na+ so water follows and swells cells. so how are transplants possible?
What is a cytopathologist?
Take cells from patient, prepare for examination and delivering expert diagnosis on cell sample
What are Biopsies?
Small tissue sections removed and preserved on a formalin solution.
Then embedded in paraffin wax to allow microtome to cut small layers
How does formalin preserve biopsies?
Crosslinks proteins
What stains can be used for biopsy microscopy?
H&E = nuclei and cytoplasmic granules of leukocytes
Ziehl-Neelsen stain = stains acid fast bacteria red for the diagnosis of TB
What are resections used for?
To look at stage of disease
How long do frozen sections take to get results?
30 mins
How long does it take to get results from Biopsies?
2-3 days
How long does it take to get results from Resections?
5-7 days
What is the downside to using fine needle aspiration?
Cytopathologist is only looking at cells and so cannot comment on architecture of tissue
What can be detected in a Kaposi’s sarcoma skin biopsy?
Spindly looking cells can be seen to penetrate collagen fibres
What can be detected in a endothelial cell tumour skin biopsy?
Would have CD31 cell marker which can be stained = brown colourisation
What syndromes can be diagnosed by their antibodies?
Systemic lupus erythematosus
Sjogren’s syndrome
Rheumatoid arthritis
What conjugations can be attached to antibodies?
Enzymes
Fluorescent probes
Magnetic beads
Drugs
What Enzymes can be attached to antibodies?
Peroxidase, alkaline phosphatase
Why may Fluorescent probes be attached to antibodies?
Allow rapid measurement of levels of molecules within sample
What drugs can be attached to antibodies?
Kadcyla - anti HER2 antibody
linked to cytotoxic emtansine
How are antibodies used?
Direct detection: bind to antigens
Indirect detection : bind to antibody antigen complex
What does ELISA stand for?
Enzyme linked immunosorbent assay
How does ELISA work?
- Add anti A antibody linked to enzyme
- Wash away unbound antibody
- Enzyme makes coloured product from added colourless substrate
- Measure absorbance of light by coloured product
What is Flow cytometry?
Cells labelled with differently conjugated Antibodies
Rub as a stream of of single cells through laser beam
Colour of light emitted and the forward or side scatter of laser beam denotes identity of cell surface molecules expressed and the size and granularity of cells
