Investigative Techniques Flashcards
What are the requirements of Light microscopy?
- Preserve tissue in formalin to prevent rotting
- Embed in melted paraffin to allow it to be thinly sliced
- Stain to see cell components
What equipment is used to thinly slice tissue?
A microtome
What is used to stain tissue?
Haemotoxylin (stains nucleus blue) and Eosin (stains cytoplasm and extracellular matrix pink)
What is the advantage of using frozen sections?
It only takes 10 minutes to prepare compared to 16hours
What is the disadvantage of using frozen sections?
It gives a lower quality
What equipment is used when doing a frozen section?
Cyrostat
What is polarised light microscopy?
When light travels in one direction
When is polarised light microscopy used?
For gout and Pseudogout
Why can you use polarised light microscopy to identify gout?
As you have too much uric acid in the blood, this precipitates into monosodium urate crystals which can be seen.
What is the problem of using a serum urate test to identify gout?
It is possible to only have urate at the joint (usually the big toe) and not in the blood
What microscopy uses the same techniques/principles as CAT scanning?
Conofocal Microscopy
What is Autoradiography?
Where you photograph molecules with radioactive markers
What is the magnification and resolution of modern light microscopy?
x1000 magnification and 0.2micrometers resolution.
What is transmission electron microscopy?
Electron beam passes through dead tissue in a vacuum
What is the magnification and resolution of TEM?
x250,000 magnification and 0.2nm resolution
What is scanning electron microscopy?
Where electrons are reflected off tissues to give a 3D image
What is the disadvantage of TEM?
Can only look at dead tissue
What is freeze fracture electron microscopy?
Where you freeze tissue to -160 degrees Celsius and fracture it by hitting with a knife edge
What is Immunohistochemistry?
Where you determine if a protein/epitope is present on a cell surface membrane
What is indirect immunohistochemistry?
Where an antibody, attaches to an epitope. The antibody has another antibody attached to it which is tagged with a chemical reagent which changes colour when stained.
What is immunofluorescent immunohistochemistry?
When an antibody with a fluorescent tag attaches to an epitope
What type of wavelength gives the best resolution with ultra sound?
Low wavelength
Does low frequency ultrasound give a high or low wavelength?
High wavelength
Which type of ultrasound contains the least energy but travels furthest?
High frequency ultrasound
