Ya Basic
These are the two biological processes that fixation helps prevent
Autolysis and Putrification
Commercial stock formalin solutions contain this percentage of formaldehyde
37-40%
This technique is often used at autopsies and necropsies to aid in penetration of fixative for thicker tissues/organs
Bread-loafing
Name one advantage to using a compound fixative.
the disadvantage of one component will be counteracted by an advantage of another.
ex: swelling of acetic acid counteracted by shrinking effect of picric acid
This type of solution will cause a cell to shrink
a hypertonic solution, the cell will shrink because water is drawn from the cell into the surrounding solution.
This is a structure or substance not normally present but produced by some external force or action
Artifact
This is primarily used for blood smears, preserving glycogen, and urate crystals
Alcohol
Smudgy nuclei and cell shrinkage seen on slide can be caused by this
delayed or incomplete fixation
This fixative is excellent for preservation of some carbohydrates, especially glycogen
Gendre Solution
This ratio of fixative to tissue is recommended for proper fixation
15-20x fixative to tissue volume
What are the Four Factors that could affect Fixation Rates
Temperature, Size, Volume, and Time
This can be used as both a fixative and a stain
Picric Acid
Treating sections with iodine and sodium thiosulfate will remove this pigment.
Mercury
Iodine oxidizes the mercury and sodium thiosulfate removes the excess from the section.
This is added to formaldehyde or NBF to create Davidson fixative
Acetic Acid and Ethanol
Using this fixative would give false positive readings using Shiff's Reagent
Glutaraldehyde
This byproduct is released during formalin cross-linking
Water
When using this fixative, sections must be small as it penetrates slowly. It is also used for electron microscopy
Glutaraldehyde
Name one of two methods used to remove formalin pigment prior to staining
Saturated alcoholic picric acid
or
70% alcohol containing ammonium hydroxide
This is used to demonstrate chromaffin and can be used to diagnose pheochromocytoma
Orth Solution
This solution is recommended for transporting tissues.
Michel Medium
Following Formalin fixation, this can be seen on slide: nuclei showing coalescence of the chromatin into strands with intervening spaces. what is this called?
nuclear bubbling
This solution can be used for electron microscopy but NOT light microscopy.
Osmium tetroxide
The Helly Fixative is dark and turbid! What could have caused this?
The Formaldehyde being added too early; it must be added immediately before use
This fixative is recommended for the Mallory PTAH stain
Zenker
Cupric (Copper) acetate