Pigments Flashcards
What are the types of artefact pigment
caused by
caused by fixation
formalin
mercury
K dichromate
What are types of exogenous pigment deposits
Carbon - strong acid
Asbestos- Perls
Tattoos- Polarised light
Metal deposits (iron – PPB, copper) - Perls
Silica - Polarised light
Lipochromes - Fluorescent microscopy
How to remove formalin artefact
- alcoholic picric acid rinse (KOH, NH3,polarised light)
how to remove mercury artefact
- iodine hypo sequence
how to remove potassium dichromate
with 1% acid alcohol
What can cause endogenous - heaemaogenous pigements and how to remove
Haemosiderin - Pels, Turnbull, Tirmann-Schmeltzer
bile - Fouchet ,Gmelin, Stein
Haemoglobin - Dunn-Thompson, Leuco patent blue (Benzidine)
What are non hematogneous endogenous stains
What is iron absorbed as
as Fe2+ in doudenum and proximal jejunum
-moves while bound to transferrin, taken up by red cell precursors to become heme
Why does iron need to be demonstrated with a special stain if tissue stained with NFR only
- Liver
PPB
target tissue
mechanism of staining
classification
positive control
target tissue- Hemosiderin
mechanism of staining - histochemica
classification - pigment stain
positive control- bone marrow, liver
asbestos bodies are PPB+
What is a histochemical method
using non colored substances to produce a non diffusible colored product
how does PPB work
target is ferritin or hemosiderin
ferric ion can be split with tissue using HCL
-Ferric ion binds with K ferrocyanide to produce ferri-ferrocyanide
-forming a blue product
What is the counter stain for PPB
Mechanism of staining
to demostrate the nuclei
- doen by ionic bonding
- needs to be a contrast color
basic dye
Neutral or Nuclear Red
Safranin
Factors that affect staining
Fixation (avoid fixatives with acid)
Metal forceps
Tap water
What is hemochromatosis
- iron overload disease
