Discuss staining methods for the demonstration of biogenic amines in tissue sections
- Chromaffin or dichromate reaction can be used to stain biogenic amines in tissue sections (e.g. adrenaline or noradrenaline in the medulla of the kidneys)
List of pigments and minerals that are introduced in the laboratory or not produced by the body
- Chromaffin
- Mercury
- Formalin
- Malaria
- Asbestos
- Silicon
- Carbon
List of pigments and minerals that are introduced in the laboratory or not produced by the body
- Chromaffin
- Mercury
- Formalin
- Malaria
- Asbestos
- Silicon
- Carbon
Adrenal chromaffin
What it is: A reaction of the amine (in this case, adrenaline or noradrenaline) with dichromate fixative
Appearance and location: Chromaffin presents in fine, yellow crystals with random distribution, but in the adrenal glands it appears in the medulla
Special stain used: Schmorl’s for lipofuscins (chromaffin appears black)
Birefringent: not birefringent
Significance: Can indicate if an individual has experienced chronic stress, patient may also experience high blood pressure
Avoidance: pigment can be avoided by using a different fixative or extracting the chromaffin with acid alcohol
Ganglion lipofuscin
What it is: Breakdown product from oxidation of lipid and lipoproteins - wear and tear pigment
Appearance and location: Can be found in adrenals, heart, ganglia, GIT etc. but presents as fine, granular matter within the secreting cell (e.g. inside ganglion cells in spinal ganglion)
Special stain used: Schmorl’s for lipofuscins
Birefringent: not birefringent
Significance: demonstrates wear and tear of organ or organ systems (e.g. neuron/nerve damage in ganglion), can indicate possible morbidities later on
Malarial liver
What it is: a malarial infection
Appearance and location: Pigment is located in RBCs that have been invaded by a malarial parasite, Kupffer cells, or macrophages that have tried to ingest the malaria. It presents as yellow-brown granular material
Special stain used: H&E and H&E with malaria and formalin removal
Birefringent: Birefringent in Kupffer cells
Significance: indicates malarial infection and damage to cells
Avoidance: Malaria can be removed from the tissue using alcohol ammonia
Bile liver
What it is: A leakage of bile into the liver and ducts
Appearance and location: bright yellow-brown pigment in the bile ducts or hepatocytes
Special stain used: Fouchet for bile
Birefringent: not bi-refringent (if old formalin is used then some refringence may appear)
Significance: can indicate colystasis, hepatitis etc.
Mercury in the kidney
What is it: a pigment introduced by fixation in mercury based fluids e.g. Formol
Appearance and location: granular black matter with random distribution in tissues
Special stain used: H&E and mercury removal with Lugol’s iodine and sodium thiosulphate (together, these form a water soluble compound that picks up residual iodine and removes mercury)
Birefringent: Collagen/scar tissue is birefringent
Significance: insignificant; introduced in the laboratory by mercury-based fluids
Avoidance: use NBF to avoid merc. pigment or extract with Lugol’s
Mercury in the kidney
What is it: a pigment introduced by fixation in mercury based fluids e.g. Formol
Appearance and location:
Silicon in the lungs
What is it: silicon shards from quartz can be inhaled by miners and accumulate in their lungs
Appearance and location: dumbell shaped structure, golden brown colour
Special stain: Perl’s prussian blue reaction (PBR)
Birefringent: yes for silicon shards
Significance: significant, can later cause fibrosis or silicosis
Carbon in the lungs
What is it: carbon can be inhaled from cigarettes and accumulate in the lungs
Appearance and location: black granular material
Special stain: PBR
Birefringent: No
Significant: can cause anthracosis later on
Gout in the knuckle
What is it: an accumulation of uric acid in the joints causes gouty arthritis, characterised by large round crystals around the joint
Appearance: in H&E, uric acid is colourless (has a slight pink blush), pockets of uric acid are surrounded by collagen and scar tissue in the knuckle
Special stain: no stain, only brought to dewax and then examined by polarising light. Gout is birefringent and appears as fine needle-like crystals
Birefringent: Yes, negative birefringence This is when the blue crystals are prependicular to the polarising filter, and yellow crystals are paralell to the filter. Positive birefringence is the inverse.
Significant: Yes; indicates gouty arthritis
Titanium in hip prosthesis
What is it: after hip translants, titanium seeps from the implant into surrounding tissues
Appearance: macrophages pick up titanium and store it within the dermis of the skin, appears as small dark brown granules
Special stain: none
Birefringent: no
Significant: yes, indicates disintegrstion of prosthetic
Haemosidern in liver
What is it: RBCs are broken down and haemoglobin is stored as haemosiderin, causing this pigment.
Appearance: groups of blue granules amongst hepatocytes in the liver, but can also appear in macrophages within fibrous scar tissue (looks like large clumps)
Special stain: PBR (haemosiderin is blue)
Significant: yes, indicates haemosiderin