Download - Pigment metabolism

PIGMENT METABOLISM

PRESENTER - Dr SHREYA PRABHU

MODERATOR - Dr ANISHA T S

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INTRODUCTION

PIGMENTS are colored substances, some of which are normal

constituents of cell, whereas others are abnormal and accumulate

in cells only under special circumstances.

They absorb visible light within a narrow band between 400-800

nm.

Thus pigments greatly differ in origin, chemical constitution, and

biological significance.

They can be organic or inorganic compounds that remain insoluble

in most solvents

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CLASSIFICATION

A)ENDOGENOUS PIGMENTS

1) HEMATOGENOUS PIGMENTS

a. Hemosiderin

b. Hemoglobin

c. Bilirubin

d. Porphyrins

2) NON HEMATOGENOUS PIGMENTS

a. Melanin

b. Lipofuscins

c. Chromaffin

d. Pseudomelanosis

e. Dubin-Johnson pigment

f. Ceroid-type lipofuscins

g. Hamazaki-Weisenberg bodies

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B)EXOGENOUS PIGMENTS

Inhaled pigments

Ingested pigments

Injected pigments

C)ARTIFACT PIGMENTS

Formalin

Malaria

Schistosome

Mercury

Chromic oxide

Starch

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ENDOGENOUS

PIGMENTS

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HEMOSIDERINS

Hemoglobin derived, GOLDEN YELLOW to BROWN granular intracellular

pigments.

They contain iron in the form of ferric hydroxide that is bound to a protein

framework

Formed by aggregates of ferritin (iron complexed to apoferritin) found

especially within the phagocytes of the bone marrow, spleen, liver where the

break down of senescent RBC takes place.

Excessive storage of hemosiderin(hemosiderosis) occurs in situation where

there is excessive breakdown of red cells or systemic overload of iron

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HEMOSIDEROSIS

LOCALISED GENERALISED

LOCAL TISSUES PARENCHYMAL DEPOSISTS

(Macrophages, fibroblasts, endothelial (Liver, Kidney, Pancreas. Heart, Skin)

cells and alveolar cells) RED CELL DEPOSISTS

(Liver, Spleen, Bone marrow)

Examples: Examples:

1.Hemorrhage in tissues 1.Acquired Hemosiderosis

2.Black eye 2.Hereditary Hemosiderosis

3.Brown induration lung 3.Excessive dietary intake (Bantus

4.Infraction disease)

DEMONSTRATION OF HEMOSIDERIN AND

IRON

PERLS PRUSSIAN BLUE REACTION FOR FERRIC IRON:

Considered to be first classical histochemical reaction.

Treatment with an acid ferrocyanide solution will result in the unmasking of

ferric iron in the form of the hydroxide, Fe(OH)3, by dilute hydrochloric acid.

The ferric iron reacts with a dilute ferrocyanide solution to produce an insoluble

blue compound, ferric ferrocyanide (prussian blue)

FIXATION:

Avoid the use of acid fixatives. Chromates will also interfere with the

preservation of iron

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10SECTIONS:

Works well on all types of section, including resin

FERROCYANIDE SOLUTION:

1% aqueous potassium ferrocyanide 20 ml

2% aqueous hydrochloric acid 20 ml

Freshly prepared just before use

METHOD:

Take a test and control section to water

Treat sections with the freshly prepared acid ferrocyanide solution for 10-30 minutes

Wash well in distilled water

Lightly stain the nuclei with 0.5% aqueous neutral red or 0.1% nuclear fast red

Wash rapidly in distilled water

Dehydrate, clear, and mount in synthetic resin

RESULTS:

Ferric iron Blue

Nuclei Red

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A SECTION OF LIVER FROM A PATIENT WITH HEMOCHROMATOSIS

STAINED FOR FERRIC IRON WITH PERLSMETHOD. FERRIC IRON IS

STAINED BLUE

LILLIES METHOD FOR FERRIC AND FERROUS IRON

Ferric iron dark Prussian blue

Ferrous iron dark Turnbulls blue

Nuclei Red

HUKILL AND PUTTS METHOD FOR FERROUS AND

FERRIC IRON

Ferrous iron Red

Nuclei Blue

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A SECTION OF PLACENTA TREATED WITH LILLIES METHOD FOR

FERROUS IRON. FERROUS IRON IS STAINED DARK BLUE

HEMOGLOBIN

HEMOGLOBIN is a basic conjugated protein bound to globin and is the red

pigment component, responsible for the transportation of oxygen and carbon

dioxide.

Heme is composed of protoporphyrin, a substance built up from pyrrole rings

and combined with ferrous iron.

Histochemical demonstration of the ferrous iron is only possible if the close

binding in the heme molecules is cleaved

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As Hb is normally present within red blood cells its

demonstration is not necessary.

Outside its normal position in RBC, Hb may be found free in

areas of recent hemorrhage, in macrophages.

The pathological conditions like casts in the lumen of renal

tubules in cases of hemoglobinuria or active

glomerulonephritis.

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DEMONSTRATION OF HEMOGLOBIN

Methods demonstrate the enzyme, Hemoglobin peroxidase,

which is reasonably stable and withstands short fixation and

paraffin processing.

This peroxidase activity was demonstrated by the Benzidine-

nitroprusside methods ( Lepehne-Pickworth Benzidine

Trchnique), but because of the carcinogenicity of benzidine, these

methods are not recommended.

Tinctorial method, The amido black technique and the Kiton

red-Almond green technique are worth noting

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LEUCO PATENT BLUE METHOD

Hemoglobin peroxidase Dark Blue

Nuclei Red

BILE PIGMENTS

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24Heme Biliverdine Bilirubin(unconjugated)

Bilirubinalbumin complex

(Uptake by liver)

Conjugated

bilirubin Bilirubin-diglucuronide

in intestine Urobilinogen

StercobilinogenUrobilinogen

In kidney

Urobilin

Excretion in urine

Stercobilin

Excretion in feces

20% absorptionEnterohepatic

circulation

80% Intestine

oxygenase

Bilirubin

reductase

Heme

Glucuronyl

transfersae

BILE PIGMENTS

Bilirubin (conjugated+unconjugated), biliverdine, hematoidin-

together refered to as Bile pigments

They are chemically and physically distinct with solubility in

water and alcohol

Bilirubin is the orange-yellow pigment, a toxic waste product

in the body.

It is extracted and biotransformed mainly in the liver, and

excreted in bile and urine.

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HEMATOIDIN-

Virchow first described in sites of old hemorrhage

Related to bile pigments but differ

Thought that heme has undergone a chemical change within these areas- led to it being trapped- preventing transportation to liver

Extracellular yellow-brown crystals and amorphous masses within old hemorrhagic areas

Microscopically- appear as bright yellow pigment in sections of old splenic infarcts, old hemorrhagic areas of brain or infarcted tissues

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Microscopical examination of any liver sections that contains bile

pigments will almost certainly reveal a mixture of biliverdine and

both conjugated and unconjugated bilirubin

In H&E stained sections- bile if present-

seen as small yellow brown globules within bile canaliculi- indicating

obstruction

Within hepatocytes (they need to be distinguished from Lipofuscin)

Conditions- Prehepatic/ Hepatic/ Post hepatic

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Intracellular

Cholestasis,

Bile pigments in

The cytoplasm

Fig: CHOLESTASIS

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BILE PLUG (arrow) showing expansion of bile canaliculus by bile

DEMONSTRATION OF BILE PIGMENTS:

Need arises in the histological examination of liver where

distinguishing from lipofuscin is of significance

Both appear yellow-brown in H&E paraffin sections

Bile pigments are not autofluorescent and fail to rotate the

plane of polarized light, whereas Lipofuscin is autofluorescent

Most common method- Modified Fouchet Technique

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MODIFIED FOUCHETS (HALL) TECHNIQUE

(FOR LIVER BILE PIGMENTS)

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RESULTS-

Bile pigments emerald to blue green

Muscle yellow

Collagen red

OTHER TECHNIQUES

GMELIN TECHNIQUE-

Only method that shows identical result with liver, gallbladder bile and

hematoidin.

Method- Deparaffinized sections of tissue treated with nitric acid and

changing color spectrum is produced around pigment deposits

Red Purple Green

KUTLIKS TECHNIQUE-

Method-Sections treated with ferric iron solution

Result- Bilirubin- Green on pale yellow background

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PORPHYRIN PIGMENTS

Normally occur in tissues in small amounts.

Considered to be precursor of the heme portion of Hb

PORPHYRIAS are rare pathological conditions that are

disorders of the biosynthesis of porphyrins and heme

Found most abundantly in liver

No method for demonstration other than Orange-red

fluorescence which they give with UV light

Porphyrins and bile pigments both give positive Gmelin

reaction

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Porphyrin pigment-

Appears as dense dark brown pigment

In fresh frozen section exhibits a brilliant red fluorescence

that fades rapidly with exposure to ultraviolet light.

In paraffin sections and viewed using polarized light,

shows as bright red in color with centrally located, dark

maltese cross

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MELANIN

Melanin (melas= black), serves protective function- absorbs UV light

In melanocytes, tyrosine DOPA Melanin

Melanin is the brown-black, non-hemoglobin derived pigment

Skin-

It is synthesised in the melanocytes which are present in the basal cells of the

epidermis

Stored in the form of cytoplasmic granules in the phagocytic cells called the

melanophages in inflammatory conditions, present in the upper dermis

Benign nevus, Malignant melanoma

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tyrosinase oxidase

Eye-

Found in choroid, ciliary body, iris

Melanomas (rare)

Brain-

In substantia nigra, macroscopically visible as black streak on both sides of

mesencephalon

Also in meninges (sooty appearance)

Parkinsons disease this area is reduced

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DISORDERS OF PIGMENTATION

HYPERPIGMENTATION:

GENERALISED- Addisons disease, Chloasma

FOCAL- Caf au lait spots, Peutz jeghers syndrome (peri oral),

Melanosis coli, Melanotic tumors

HYPOPIGMENTATION:

GENERALISED- Albinism (tyrosinase activity of melanocytes genetically

defective)

FOCAL- Leucoderma ( form of partial albinism), Vitiligo

ACQUIRED FOCAL- leprosy, healing of wounds, DLE, radiation

dermatitis

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PERIORAL HYPERPIGMENTATION

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ALBINISM VITILIGO

HYPOPIGMENTATION

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MALIGNANT MELANOMA

METHODS FOR MELANIN

Reducing methods- Fontana silver method, Schmrols

reaction

Enzyme methods

Fluorescent methods

Immunohistochemistry

Solubility and bleaching characteristics

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MELANIN AND ITS

PRECURSORS:

Are capable of reducing both

silver and acid ferricyanide

solutions

MELANINS:

Completely insoluble in most

organic solvents

Bleached by strong oxidizing

agents

Powerful reducing agents

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REDUCING METHODS

PRINCIPLE-

Melanins argentaffin property- that is the reduction of

ammonical silver solutions to form metallic silver without the

need for a separate reducing agent.

Melanin is also Argyrophilic, melanin is colored black by

Silver impregnation methods

Reduce ferricyanide to ferrocyanide with production of

Prussian blue in the presence of ferric salts

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50MASSON-FONTANA METHOD

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MELANIN PIGMENT IN CELLS OF MALIGNANT MELANOMA,FONTANA-MASSON STAIN

SCHMORLS REACTION:

Melanin Dark blue

Nuclei Red

LILLIES FERROUS ION UPTAKE REACTION:

Melanin Dark green

Nuclei Red

LILLIES NILE BLUE METHOD:

Melanin Dark blue

Lipofuscin Dark blue

Nuclei Red

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SECTION OF SKIN STAINED BY SCHMORLS REAGENT POSITIVE FOR

MELANIN

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ENZYME METHODS

Cells that are capable of producing melanin can be

demonstrated by DOPA method

These methods are those of

Bloch and Laidlaw and Blackberg for tissue sections

Bloch and Rodriguez and McGavran for tissue blocks

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SOLUBILITY AND BLEACHING METHODS

Melanins are insoluble in organic solvents

Due to tight bound it has with its protein component

Use of strong oxidising agents will bleach melanin (slow, 16

hours)

Method of choice- Peracetic acid

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FORMALIN-INDUCED FLUORESCENCE

Certain aromatic amines like 5-HT, Dopamine, Epinephrine,

Norepinephrine, Histamine- show yellow fluorescence when

exposed to formaldehyde

Useful when demonstrating Amelanotic melanoma

Results- Melanin precursor cell- Weak yellow fluorescence

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LIPID PIGMENTS/CHROMOLIPIDS

Have lipid characteristics

These are:

1. Lipofuscins

2. Ceroid

3. Alcoholic hyaline

4. Lipochromes

5. Pseudomelanosis pigment

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LIPOFUSCINS

Wear and tear pigment/ Brown atrophy pigments/ abnutzung pigments

Produced by oxidation process of lipids and lipoproteins with aging

Yellowish brown intracellular pigment

M/E- coarse golden brown granular pigment, accumulates in central part

of the cells around the nuclei.

These are formed by slow progressive oxidation process, thus reactions

vary according to the degree of oxidation present in the pigment

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Found in:

Atrophied cells of old age

Hepatocytes

Cardiac muscle cell (brown atrophy of heart)

Inner reticular layer of normal adrenal cortex

Testis, in interstitial cells of Leydig (gives tissue brown color)

Ovary

Edge of cerebral haemorrhage or infarct

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DEMONSTRATION OF LIPOFUSCINS

Periodic acid- schiff method

Schmorls ferric-ferricyanide reduction test

Long ziehl-Neelsen method

Sudan black B method

Gomoris aldehyde fuchsin technique

Masson-Fontana silver method

Churukians silver method

Lillies Nile blue sulfate method

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CEROID

It is a mixture of Lipofuscin like pigment, probably represents it in an

early stage of formation

Occurs in

Atheroma

Alcoholic cirrhosis

Occurs as globules of yellow material within macrophages

Differs from lipofuscin by negative Schmorl reaction

Exhibits autofluorescence-

greenish yellow in frozen sections

Brownish yellow in paraffin sections

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ALCOHOLIC HYALIN

Hyaline eosinophilic material, irregular to round mass

(Mallory bodies) near the nuclei of liver cells in chronic

alcoholics

Represent enlarged, distorted, degenerated mitochondria

Affinity towards acid fuchsin and eosin

MALLORYS HEMALUM-PHLOXINE METHOD-

Alcoholic hyalin- red

Nuclei- blue

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PSEUDOMELANOSIS PIGMENT

Pseudomelanosis condition in which a dark brown, melanin-

like pigment is found in macrophages in the mucosae of the

large bowel and appendix

Stains blue-green in the ferric-ferricyanide reduction test

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PSEUDOMELANOSIS PIGMENT

OTHER ENDOGENOUS PIGMENTS

CHROMAFFIN:

Normally found in adrenal medulla as dark brown, granular material. Occur in

tumors of adrenal medulla- pheochromocytoma

Demonstrated by Schmorls reaction, Lillies Nile blue A, the Masson-Fontana,

PAS technique

DUBIN-JOHNSON PIGMENT:

Found in liver of patients of Dubin-Johnson syndrome- brownish black, granular,

intracellular pigment, situated in the centrilobular hepatocytes

HAMAZAKI-WEISENBERG BODIES:

Small, yellow brown spindle shaped structures in sinuses of lymph nodes in

patients with sarcoidosis

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EXOGENOUS PIGMENTS

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Introduced in the body by- Inhalation /

Ingestion /Inoculation

Broadly classified as

1. Inhaled pigments (Carbon)

2. Ingested pigments (Lead)

3. Injected pigments (Tattooing)

Majority of these pigments are infact colorless, some are

inert and unreactive

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TATTOO PIGMENT

Tattooing is a form of localized, exogenous pigmentation of the skin.

Pigments like India Ink, Cinnabar, Carbon inocluated are phogocytosed

by dermal macrophages, in which they reside for the remainder of the life.

Pigments do not usually evoke any inflammatory response

Examples-

Tattooing by pricking the skin with dyes

Prolonged use of ointments containing mercury

Dirt left accidently in a wound

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CARBON

Most commonly seen mineral in tissue.

Commonly found in lung and adjacent lymph nodes of urban dwellers and tobacco smokers

MAIN SOURCE- Car exhausts, smoke from domestic and industrial chimneys.

Black pigmentation of the lung (Anthracosis) is result of massive depostion of carbon in coal workers.

Macroscopically lungs appears almost Black. Lung disease is known as Coal workers pneumoconiosis ( found in association with silica found with coal and other mineral ores)

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86The pigment particles on inhalation are trapped by the thin film of mucus in the nose,

pharynx, trachea and bronchi

Small amount reaches alveoli and taken up by alveolar macrophages

Some of the pigment-laden macrophages are coughed out via bronchi, while some settle in the

interstitial tissue of the lung and in the respiratory bronchioles and pass into lymphatics to be

deposited in the hilar lymph nodes

Carbon is extremely unreactive and inert and fails to be demonstrated with the

conventional histological stains and histochemical methods.

The site and nature of carbon deposits make identification relatively easy.

It may be confused with melanin deposition but treatment with bleaching agents will

show carbon unaffected, whereas melanin will be dissolved.

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ANTHRACOSIS LUNG

SILICA

In the form of silicates is associated with the majority of all

mined ores, also abundant in stone and sand and industries

involved in grinding stone or sand blasting.

Mine workers inhale large quantities of silica that can give

rise to the disease SILICOSIS.

Silicosis consists of diffuse, nodular, whorled proliferation of

fibrous tissue surrounding the tiny doubly refractile silica

crystals when examined by polarized light.

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Silica is unreactive thus not demonstrated by histological

stains and histochemical methods.

It is anisotropic (birefringent) when examined using polarized

light.

HEMATITE LUNG-

Mining hematite (ferric oxide) from quartz ores

Silica from quartz play major role

Iron in hematite lung fail to give Prussian blue reaction unless treated

before with 40% HCl

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ASBESTOS

Special form of silica used as a fire resistant and insulating material.

Type of asbestos fibers that cause pulmonary disease are called AMPHIBOLES.

Dangerous type is CROCIDOLITE. Fibers are 5-100 m long and only 0.25-0.5

m in diameter and can collect in the alveoli at the periphery of lung.

Fibers are anisotropic but fail to show birefringence when appear as asbestos

body

ASBESTOS BODY Characteristically beaded, yellow- brown, dumb-bell shaped

in lung sections. The proteinaceous coat contains hemosiderin and is positive with

Perls Prussian blue.

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941) In case where asbestosis is suspected but no asbestos fibres or bodies are demonstrable

lung tissue from lower lobes can be digested with 40% sodium hydroxide.

Resultant tissue sludge is then centrifuged and washed in water

Smears from the deposit are made and examined using polarized light

2) Thick paraffin sections of lung tissues are mounted on glass slides coated with an adhesive

The sections are dewaxed and mounted unstained and then examined using polarised light

(Many thick sections may be needed before a positive result is seen)

DEMONSTRATION OF ASBESTOS FIBRES

LEAD

Environmental pollution due to Lead has been greatly reduced

Lead pipes that carried much of the domestic water supply have been replaced and lead in

paint, batteries and gasoline has also been reduced

Lead poisoning cases are rare and usually diagnosed biochemically using the serum

In chronic lead poisoning, excessive amounts can be deposited within many tissues,

particularly bone and kidney tubules

Demonstrated by various methods- Rhodizonate method (popular), Sulfide silver of

Timm, the unripened hematoxylin technique of Mallory and Parker, but neither of these is

specific for Lead.

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RHODIZONATE METHOD

RESULTS:

Lead salts Black

Background Green

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BERYLLIUM AND ALUMINUM

BERYLLIUM is used in the manufacture of fluorescent light tubes and gains

access to the body by inhalation or traumatization of the skin

A foreign body granuloma is formed.

These bodies usually give a positive reaction with Perls Prussian blue.

ALUMINUM rarely seen in tissues but gains access to the body in similar

way to Beryllium

It can also be found in bone biopsies from patients on regular hemodialysis

for chronic renal failure

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SOLOCHROME AZURINE METHOD FOR BERYLLIUM AND ALUMINUM

RESULTS:

Solution A: Aluminum and Beryllium Blue

Solution B : Beryllium only Blue-Black

Nuclei Red

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105ALUMINON METHOD FOR ALUMINUM

RESULTS-

Aluminium Red

Background Green

SILVER

Rarely seen in the skin of silver workers as a result of

industrial exposure

Resultant permanent Blue-Gray pigmentation is called

Argyria and is marked in Sun exposed areas

Now commonly seen as localized change in mouth (amalgam

tattoo)

In unstained and H&E sections the silver appears as fine

dark brown or black granules, particularly in basement

membranes and sweat galnds.

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RHODANINE METHOD

METHOD:

Paraffin sections to distilled water

Incubate sections in rhodanine solution at 37C for 24 hours

Wash well in distilled water

Mount in glycerin jelly

RESULTS:

Silver deposits Reddish- brown

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SIVER PIGMENT- RHODANINE METHOD

ARTIFACT

PIGMENTS

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This group of pigments comprises:

Formalin

Malaria

Schistosome

Mercury

Chromic oxide

Starch

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FORMALIN PIGMENT

a/k/a ACID HEMATIN, formed after several weeks in specimens by the interaction of acidic formaldehyde solutions with blood.

Traces of formic acid are formed by oxidation, which decreases the quality of nuclear staining and leaches out hemosiderin resulting in formation of formalin pigment.

COLOR- Brown or Brownish-Black deposit in tissues (product of degradation of hemoglobin, settles out as an insoluble product, extracelluarly)

MORPHOLOGY- Vary, commonly seen as microcrystalline deposit that is anisotropic(birefringent).

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The deposit is usually present in blood rich tissues such as

spleen, blood vessels, hemorrhagic lesions.

Fixation of these organs for long period will tend to increase

the amount of formalin pigment formed. Under these

conditions it is advisable to change the fixative on regular

basis.

Use of Buffered neutral formalin will help to minimize the

problem of formalin pigment deposition.

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Section of Kidney showing formalin pigment

REMOVAL OF FORMALIN

PIGMENT BEFORE STAINING

PICRIC ACID METHOD: Treat sections in saturated solutions of picric

acid for 5 minutes to 2 hours.

SCHRIDDES METHOD: Treat sections for 30 minutes with a mixture of

200 ml of 75% alcohol and 1 ml of 25-28% liquor ammonia. Wash in

water.

VERCAYS METHOD: Treat sections for 10 minutes with a mixture of

100 ml of 80% alcohol and 1 ml of aqueous potassium hydroxide. Wash

in water.

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LILLIES METHOD: Treat sections for 1-5 minutes with a

mixture of 50 ml of 75% acetone, 50 ml 3% hydrogen

peroxide and 1 ml of 28% ammonia water followed by

washing in 70% alcohol and then in running water.

KARADASEWITSCHS METHOD: Treat sections for 30

minutes to 1 hour with a mixture of 100 ml of 70% ethyl

alcohol and 1 ml of 28% ammonia water. Wash in water.

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MALARIAL PIGMENT

Morphologically similar to formalin pigment exhibits birefringence.

It is formed within or in the region of RBC that contain the parasite

The pigment sometimes may be so dense that can obscure the vision of

parasite in RBC

Pigment can also seen in the phagocytic cells that ingest the infected RBCs.

Thus should examine for Kupffer cells of liver, the sinus lining of lymph nodes

and spleen, and within phagocytic cells of bone marrow.

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117MALARIAL PIGMENT

IN PLACENTA IN SPLEEN

EXTRACTION OF MALARIAL PIGMENT

REAGENT-

Removed with saturated alcoholic picric acid for 12-24 hours

PROCEDURE-

1. Bring sections to water.

2. Place the sections in alcoholic picric acid

3. Rinse sections in 90% alcohol

4. Rinse sections in 70% alcohol

5. Place sections in tap water

6. Stain with H&E or other routine stain

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MERCURY PIGMENT

Pigment seen in the tissues that have been fixed in the mercury containing

fixatives (B5, Heidenhains, Zenkers fluid)

MORPHOLOGY-

Varies, usually seen as Brownish black, extracellular crystal, monorefringent

(birefringent when formalin fixed tissue has been secondarily fixed in formal

mercury)

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SECTION OF KIDNEY SHOWING MERCURY

PIGMENT

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REAGENTS:

1. Lugols iodine 1 g, Potassium iodide 2 g, distilled water 100 ml

2. 5% aqueous Na2S2O3 (sodium thiosulphite)

METHOD:

1. Bring sections to water

2. Place in Lugols iodine for 15 minutes

3. Wash in water

4. Place in thiosulfate for 3 minutes

5. Wash in water

6. Stain with H&E or other technique

NOTE:

Advisable to not remove mercury pigment with iodine solutions prior to staining with grams method as

the connective tissue will take up crystal violet and then resist acetone decolorization.

123SCHISTOSOME PIGMENT:

Occasionally seen in tissue sections infested with Schistosomes.

Pigment tends to be chunky, properties similar to formalin and malarial pigments.

CHROMIC OXIDE:

Pigment rarely seen. Presents as fine yellow-brown particulate deposit,

monorefringent and extracellular in tissues fixed in chromic acid or dichromate

containing fixatives.

Removed from tissues by treatment with 1% acid alcohol.

STARCH:

Pigment introduced by talcum powder from the gloves of surgeon/ nurses/

pathologists.

It is PAS and Gomori Methamine Silver Positive and produce Maltese cross

configuration when polarised.

REFERENCES

1. Kumar v, Abbas K A, Aster C J. Cellular responses to stress and toxic insults: Adaptation, Injury and death. In: Kumar v, Abbas K A, Aster C J, editors. Robbins and cotran pathological basis of disease. 9th ed. New delhi : Elsevier ; 2014

2. Strayer S D, Rubin E.cell adaptaion, cell injury and cell death. In: Rubin R, Strayer S D, editors. Rubins Pathology: clinicopathological foundations of medicine. 6th ed. China: Lippincott Williams and Wilkins;2012

3. John D Bancroft, Marilyn Gamble, Pigments and Minerals: Theory and Practice of Histological techniques. 6th Edition

4. Ivan Damjanov, James Linder, Andersons Pathology, 10th edition

5. Lynchs medical Laboratory Technology

6. Principles and interpretation of laboratory practices in surgical pathology, Shameem Shariff, Amrit Kaur Kaler

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