Pigments and lipids Flashcards
what is perls staining used for and
detects the presence of iron
what is an artefact
deposits produced as result of a chemical reaction in tissue
define Endogenous
haematogenous or autogenous
produced within the tissue and have physiological function or are a by- product of normal metabolic process
define Exogenous
gain access to body accidentally with no physiological function. Usually minerals, enter by inhalation or implantation in skin during industrial exposure.
what are the artefact pigments ?
formalin
malarial
mercury
dichromate
what is formalin pigment and how is it removed
brown/black deposit following fixation in acid
formalin, especially seen in haemorrhagic tissue. Removed with picric acid
how is formalin pigment formed
Formalin pigment is formed from haemoglobin by the action of formaldehyde at acid pH (prevented by short fixations in neutral buffered formalin). In and around blood vessels
what is malarial pigment
similar to formalin pigment, formed in/near RBC’s
with parasite.
how is malarial pigment formed
Malarial pigment, brown/black pigment occurs in parasitic infection (such as Plasmodium malariae). In and around blood vessels. Left over from the metabolism of haemoglobin by the malarial parasite
what is mercury pigment
black deposit formed with fixatives containing
Mercury. Removed with iodine/hypo
how is mercury pigment formed
Mercury pigment can develop when mercuric chloride is incorporated into fixatives
What are dichromate deposits
yellow/brown deposits after potassium
dichromate fixation and insufficient washing prior to dehydration. Removed
with acid alcohol
how are dichromate deposits formed
Dichromate deposits can form after fixation with potassium dichromate containing fixatives and insufficient washing to remove any excess fixative
what are the three types of pigments and how do we differentiate between them
Endogenous - related to the cell as have physiological function (eg might always see them around the nucleus)
Artefact - non-related to cells so will be present everywhere
Exogenous- enter body via airways/skin
what is Lipofuscin
yellow-brown pigment granules composed of lipid-containing residues of lysosomal digestion. Aging or ‘wear-and-tear’ pigments
what are the two types of endogenous pigments
haematogenous and non- haematogenous
what are haematogenous pigments
haemoglobin:
globin - protein part
heme - pigment part:
splits off into iron or bile pigments
where are bile pigments found
liver/gall bladder/spleen etc
what do bile pigments do
Follows breakdown of RBC’s and release of haemoglobin and iron removal, leaving biliverdin. Transported to liver by phagocytic cells, reduced to bilirubin.
what is Haematoidin and where is it seen
an orange-yellow pigment in the bile that forms as a product of hemoglobin; excess amounts in the blood produce the yellow appearance observed in jaundice
Haematoidin seen in spleen haemorrhagic areas, sometimes brain
what are the three bile pigments and what type of pigment are they
biliverdin, bilirubin, haematoidin
endogenous
what does the bile - obstructive jaundice look like in histology and how is this caused (in general)
Accumulation of pigments – bile
Often this is due to extrahepatic biliary tract obstruction
Bile may also accumulate in liver (called cholestasis) when there is hepatocyte injury
what does an H&E stain of bile - obstructive jaundice look like (colour)
Orange pigment in bile ducts in portal areas liver in H&E. Higher magnification of area more impacted by obstruction of bile ducts
on a bile - infarction slide what would you see
lysed hepatocytes
what is Cholestasis
bile accumulation in the liver
facts on Lipofuscin and what type of pigment is it
Oxidation of lipids. Normal in ageing process, abnormal in Vit E deficiency. Seen in heart, liver, adrenal, testis, neurones. Stained by Sudan Black, PAS, Schmorl’s, Long Zn
endogenous
facts on melanin and what type of pigment is it
Intra cellular, brown/black. Normal in skin, retina, brain, hair shafts. Pathologically in benign naevus cell tumours, malignant melanoma Demonstrated by Masson Fontana (black)
endogenous
steps in the formation of melanoma (phases and key points)
- Benign Nevus - BRAF mutation
- Dysplastic Nevus - CDKN2A & PTEN loss
- Radial growth phase - CD1 increase, move from epidermis to dermis
- Vertical growth phase - E-cadherin loss
- Metastatic Melanoma - break basement membrane and move into cells, Distant metastases
what is a Nevus
birthmark or mole
what is iron stored as, where and in what state
Stored as haemosiderin in marrow and spleen in ferric (Fe+3) state
iron clour
fine brown
what test demonstrates iron
Perl’s Prussian Blue reaction
what is Haemosiderin
iron storage found in cells of tissues (not including that in circulating blood). The iron within deposits of hemosiderin is very poorly available to supply iron when needed
what is Haemosiderosis
iron overload disorder resulting in the accumulation of haemosiderin
what would a slide of haemosiderin in the kidney look like
Perls reaction (iron)
haemoglobin breakdown - blue present
what are heart failure cells
hemosiderin-containing macrophages generated in the alveoli of patients with heart failure or chronic pulmonary edema, when the high blood pressure causes red blood cell to pass through the vascular wall (H&E)
What tests distinguish calcium
Demonstrated by Von Kossa (black), Alizarin red (red)
what is calcuim
Insoluble, inorganic salts in bone/teeth
what does wilsons disease have abnormal levels of
copper
Facts on copper
Normal constituent of many tissues, part of some of the oxidase enzymes.
Present in very small amounts.
Abnormal levels in Wilson’s disease, seen in liver cirrhosis, brain.
three tests for copper and colours
Demonstrated by Shikata Orcein (brown), Rubeanic acid (green/black), Rhodanine stain (red, picture)
one distinguishing feature in a patient with wilsons disease?
deposit of copper in cornea (visible as a brown ring on the edge of the cornea)
what are uric acids and urates
Breakdown product of Purine metabolism, normally further broken down and excreted in urine
what causes gout and how?
uric acids and urates:
they do not break down and remain as accumulations , becoming crystallised in tissue (joints) leading to chemical arthritis. Produce gouty “tophi”
how is gout seen on a slide/what stain is used
Demonstrated by silver stains (black). Seen as birefringence in polarised light.
what is Birefringent
Birefringent is the optical property of a material having a refractive index that depends on the polarization and propagation direction of light
(POLARISED LIGHT)
what do uric acid “Tophi” look like on a slide
Needle-shaped crystals in surrounding fibrous tissue
examples of Exogenous pigments
carbon and asbestos
what is Carbon pigment (and facts) and what type of pigment is it
Most common of the pigments, seen in lungs of urban dwellers, smokers. Absorbed by phagocytes. No histological methods, easy to identify (site), may be confused with melanin
Exogenous
what is Asbestos pigment (and facts) and what type of pigment is it
Long beaded fibres (silica), cause fibrosis, may lead to asbestosis and mesothelioma.
Fibres become coated in protein sheaths containing haemosiderin,
histology staining for asbestos?
demonstrated by Perl’s Prussian Blue (asbestos bodies).
histology staining for carbon
no histological methods
what is coal workers lung called
anthracosilicosis
what causes coal workers lung
The accumulation of carbon (anthracosis) and silica (silicosis) in the lungs from inhaled coal dust.
Pathogenesis particles are taken up by macrophages and they store them. Production of fibrogenic factors, toxic factors, and proinflammatory factors
what are other names for coal workers lung disease
pneumoconiosis or silicoanthracosis.
Pathogenesis particles are taken up by macrophages and they store them. Production of fibrogenic factors, toxic factors, and proinflammatory factors
pathogenesis in detail of coal workers lung disease
- silica/coal/asbestos enters alveolar and taken up my macrophage
Results-
2a. Recruitment and activation of inflammatory cells (IL-6, TNF-a) etc causing more toxic factors to be released
2b. Toxic factors (proteases, O2, free radicals) released and cause lung injury - fibrosis
2c. Fibrogenic factors (TNF-a, fibronectin) recruit fibroblasts and collagen production - fibrosis
what does an asbestos body look like in histology
dumbell shaped body
what 3 things do asbestos bodies cause in the alveolar
interstitial fibrosis
pleural fibrosis
pleural plaque
define lipids
naturally occurring fats and fat-like substances, usually insoluble in water, but soluble in fat-solvents
what do lipids look like in histology
big clear blobs
what enzymes break down lipids
bile salts, esterases, lipases
true or false - fats are essential for the absorption of vitamins
true - except for B group
what are fat cells called
adipocytes
what are the classification of lipids
simple lipids
compound lipids
derived lipids
hydrocarbons
examples of simple lipids
neutral lipids and waxes
examples of compound lipids
Phospholipids, Cerebrosides
examples of derived lipids
Fatty Acids, Alcohols
examples of hydrocarbons
Carotenoids
what are the different ways we can identify lipids in histology
- solubility
- examination by polarised lipids
- reduction by osmium tetroxide
- demonstration by other fat soluble dyes (lysochromes)
- other staining and histochemical methods
what is an oval fat body and where are they observed
A cell body filled with fat droplets and no visible nucleus
(degenerated renal epithelial cells) are often observed in nephrotic syndrome of any origin
what do lipids look like when they have been reduced by osmium tetroxide
dark/black blobs
name some lysochromes (fat soluble dyes)
Sudan VI
Sudan black
Oil Red O - red/pink blobs
Nile blue
what does lysochrome mean
fat soluble dyes
what is Lipidoses
lipid storage disease:
a disorder of lipid metabolism; abnormal levels of certain fats accumulate in body. They are classified by the enzyme defect or the type of lipid involved (e.g. Sphingolipidoses)
what is lipidoses an end product of
enzyme problem - genetic
where does lipidoses usually occur
Majority in Central Nervous System (e.g. Ganglion cells in rectum
what are the limitations of lab technique staining for lipids
Physical properties of lipids – change from “norm” of reaction (pure lipids stain differently from mixtures)
Melting points – 370C = fluid in body, solid in section, therefore may or may not stain or react with reagents
