Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Histology2 > Pigments, Minerals &Cytoplasmic Granules > Flashcards

Pigments, Minerals &Cytoplasmic Granules Flashcards

1
Q

Pigments

A

Visible substances in tissue found either naturally or as a result of a disease process

Pigments may be:
Artifacts
Exogenous
Endogenous

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Artifact pigments

A

Produced by a chemical reaction with a tissue component

Most common are those caused by fixation
Acid hematin
Mercury pigment
Chrome pigment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

mercury pigment

A

Caused by mercury containing fixatives

Must be removed with iodine

Iodine is removed with hypo (sodium thiosulfate)

Mercury containing fixatives include B5,Zenker & Helly

Mercury pigment cannot be prevented

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Chromate Pigment

A

Easily prevented, wash tissues after fixation

Most authors feel it cannot be removed but some say acid alcohol will remove it

Examples of fixatives: Zenker, Helly, Orth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Formalin Pigment

A

One of three acid hematins ( other 2) :
Malarial pigment
Hydrochloric acid pigment

Characteristics:
Birefringent
Microcrystalline, dark brown
No iron reaction
prevented by buffering in neutral pH
Dissolved with alcoholic picric acid or Alcoholic alkalis *
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Exogenous Pigments

A

**Most common is carbon, a black substance resistant to bleaching and extraction with sulfuric acid – anthracotic pigment

Asbestos- birefringent fibers which become coated with iron containing protein & known as asbestos bodies. Asbestos bodies stain with Prussian Blue
- look like dumbells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Exogenous substances

A

Tattoo pigments are found in skin & occasionally in proximal lymph nodes

Minerals are not pigmented but some may enter the body & lead to disease

Examples: silica, lead, beryllium, aluminum, silver (fillings, piercing) See your notes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Endogenous Pigments

A

Hematogenous ( comes from blood) :

  • Hemoglobin
  • Hemosiderin
  • Bile

Non-hematogenous ( doesn’t come from blood) :

  • Lipofuscin ( wear & tear ) - looks the same as bile so need to differentiate bc liposfusion is harmless but bile is bad
  • Melanin( skin, hair, eye color)

All of these pigments appear as yellow to brown

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Hemoglobin

A

endogenous hematogenous

Hemoglobin, normally confined to RBCs may be found in areas of hemorrhage or hemolysis

Stains with Leuco Patent Blue

Not performed regularly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

hemosiderin

A

endogenous hematogenous

Iron stores in the body consist of hemosiderin

Increased in disease:
Hemachromatosis, Hemolytic anemia

Stained with Prussian blue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

bile pigment

A

endogenous hematogenous

Bile Pigment (bilirubin) may accumulate in liver when there is an obstruction

Staining involves converting bilirubin to biliverdin using trichloracetic acid in fouchet’s reagent

The green of biliverdin exhibits the bile pigments

bilirubin–(trichloracetic acid in fouchets reagent)–>bilirverdin(green)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

lipofuscin

A

endogenous- non hematogenous- lipidic

Lipofuscin- “wear & tear” pigment ( harmless)

Found in heart, liver, & neurons of older persons

Stains with oil-red-o & sudan black ( bc of these are lipid stains) & PAS
Negative with bile stain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Ceroid

A

endogenous - non- hematogenous lipidic

Ceroid is rarely seen in humans

Stains with oil-red-0, sudan black, PAS but also is acid-fast

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Melanin

A

endogenous non- hematogenous non- lipidic

Melanin is derived from tyrosine

A brown-black pigment

Normal in skin, hair, retina, iris & parts of CNS

Normal melanin may obscure the view of other tissue components
Melanin is removed by:
Peroxide (bleaching)
Strong alkali

Melanin is not removed by:
Weak acids or bases
Organic solvents

  • looks like carbon but carbon isnt removed with bleaching & is removed w/sulfuric acid

( dont need to know) Melanin synthesis involves the formation of dopa (3,4 dihydroxyphenylalanine)- as an intermediary step. This can be used to identify melanocytes histochemically

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

melanin - turnbull reaction

A

The solubility of melanin can be used for identification

Melanin is strongly basophilic and reduces silver nitrate to metallic silver (argentaffin)

Gives a positive Schmorl reaction bc its argentaffin

Complexes with *ferrous iron which may be demonstrated by the *Turnbull reaction

  • ferric is most common form of iron in the body not ferrous
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Endogenous Minerals- Urates

A

Urates-deposited around joints in persons with uric acid metabolism disorders. * gout

Accumulate to form “tophi”
- Painful gout

Urates are water & lithium carbonate soluble
- Lithium carbonate extraction as control

Alcohol fixation or frozen section required For identification using either method

Birefringent

  • Polarization may be used to ID
  • Also used to examine body fluid ( uric crystals)

Methenamine silver stain
- With & without lithium carbonate treatment may be used

17
Q

endogenous minerals- Calcium

A

Abnormal deposits are found in necrotic areas of tissue (salts of phosphates & carbonates) calcium is often with salt not usually stained alone i

Stains purple-blue with H & E

von Kossa silver method

Alizarin red

18
Q

Cytoplasmic Granules

A

Group of body cells which exhibit common processes related to
hormone synthesis*

All these cells have a high uptake of amine precursors and the ability to decarboxylate
(APUD cells )

These cells are demonstrated by argyrophil / argentaffin reactions

  • Adrenal chromaffin cells
  • Pancreatic endocrine cells
  • Gastrointestinal enterochromaffin cells
  • “C” cells of the thyroid
  • Neuroendocrine pituitary cells
19
Q

fixation & preserving cytoplasmic granules

A

Chromaffin is best preserved by chromate containing fixatives (Orth)

Argentaffin GI granules are destroyed by alcohol fixation

Paneth cell granules are destroyed by acetic acid

20
Q

APUD staining

A

While these cells may be stained using the metalllic impregnation methods( massson trichrome ) in this section they are generally stained today using immunohistochemistry

21
Q

Prussian Blue Stain

A

A true histochemical reaction

Prussian blue is not a dye but a reactant colored product

Ferric iron is normally found in tissues

Large deposits in Hemachromatosis or Hemosiderosis

Reagents are potassium ferrocyanide & HCL

Ferric iron forms an insoluble bright blue pigment

Do not confuse with ferrous ions (Turnbull reaction)

22
Q

Prussian Blue Stain steps

A

Hydrate

Handle with non-metal forceps

Mix 2% Pottassium Ferrocyanide & 2% Hydrochloric acid half & half,

heat 20 min at 60°C.

Wash with distilled

Counterstain (Nuclear fast red, Neutral red Eosin)

Rinse , DCM

23
Q

Prussian Blue stain results

A

Results

Nuclei and hemofuchsin…….Bright red
Hemosiderin (iron)…………….Blue
Background ……………………..Pink

24
Q

Precautions for Iron Stains

A

Be sure glassware is chemically clean
- Beware of iron Hematoxylin or ferric chloride

Iron may be dissolved by acid fixatives or decal
- False negative

Control with limited iron content is desirable to avoid possible background staining

25
Q

Turnbull Blue

A

For ferrous iron not to be confused with ferric iron

Ferrous iron in tissues is extremely rare

This reaction is however used for the Schmorl technique

The reaction is different, we use ferricyanide not ferrocyanide to produce ferrous ferricyanide

26
Q

Prussian vs Turnbull Blue

A

PRUSSIAN
Detects the usual iron storage compound

Detects ferric iron (hemosiderin) Fe3+

Uses potassium ferrocyanide

Used also for colloidal iron

TURNBULL
Detects a rare iron storage compound

Detects ferrous iron
Fe2+

Uses potassium ferricyanide

Used also for schmorl technique

27
Q

Schmorl technique used on

A

Used to indicate the presence of reducing substances in tissue

Melanin
Argentaffin granules
Formalin pigment

28
Q

Schmorl Technique for reducing substances

A

Employs the Turnbull reaction

Staining solution contains ferric iron

Used to detect reducing substances in tissue
Reducing substance reacts with ferric iron to form ferrous iron

Ferrous iron reacts with ferricyanide to produce ferrous ferricyanide (Turnbull blue)

May be used with Mayer’s mucicarmine for GI (mucin is stained)
May be used without the mucicarmine & mentanil yellow steps & counterstained with nuclear fast red instead

Same precautions as Prussian blue ( non metal forcepts)

May be used for melanin (argentaffin)

Generally replaced with IHC

29
Q

Fontanna-Masson steps

A 
Hydrate section & appropriate control
Immerse in silver nitrate, 1 hour 56°C
Rinse in DI
Tone
Fix, counterstain, DCM
30
Q

Fontanna-Masson

A

An argentaffin technique for melanin or certain cell granules

Any reducing substance will give a positive reaction

Also replaced generally by IHC

Overstaining causes background staining & loss of contrast *

When staining for melanin, use two slides & bleach one. (potassium permanganate or peroxide)

This makes the method more specific

31
Q

Argyrophil Stains

A

Grimelius & Churukian are two silver methods for detection of granules in neurosecretory tumours

Both use hydroquinone as a reducer & are counterstained with nuclear fast red (kernechtrot)

IHC is a more accurate means of ID

32
Q

GMS for Urates

A

Must be alcohol fixed bc water & lithium carbonate soluble

Same principle as fungal stain

Stained a longer time

Frozen section and polarizer could be used instead

33
Q

Bile Stain

A

Ferric chloride in trichloracetic acid (Fouchet reagent) oxidizes bilirubin to biliverdin which is a green color.

van Gieson’s is used as a counterstain

Differentiates lipofuscin & bile (bilirubin)

Bile or bilirubin ……..green
(emerald to olive)

Backround ……………yellow

34
Q

Calcium Staining

A

von Kossa – an interesting metallic impregnation technique that uses light as a reducer

Alizarin Red S – a dye which forms a chelation complex with calcium

H&E stains calcium purple - blue

35
Q

Von Kossa

A

actually a carbonate and phosphate staining method

calcium is found in tissues attached to these substances

Indirect staining method

36
Q

von Kossa stain steps & results

A 
Hydrate
Place sections in silver and expose to light
Rinse in DI
Fix in hypo
Counterstain in nuclear fast red
Wash, DCM
RESULTS…….calcium- black
                    background- red
37
Q

Alizarin Red S

A

Using a pH of 4.1 – 4.3 for this staining method is important

At this pH the stain is said to be specific for calcium (by some)

This pH may cause the localization of the calcium to be diffuse

38
Q

Copper Staining

A

Seldom required

WILSON’S DISEASE*** is quite rare, deposits usually in liver

Methods used include:
RHODAnine (more sensitive, less specific)
RUBEANic acid (Uzman’s) less sensitive, more specific

Shikata Orcein (probably not as sensitive)

Histology2 (14 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions