FIXATION LECT- 💡part 4

PICRIC ACID

Can act as a fixative, can be used as a stain and also used as decalcifying agent

PICRIC ACID

EXCELLENT FOR: Glycogen demonstration

PICRIC ACID

Major drawback: Imparts a yellow color when used as a fixative

Saturated solution of Lithium carbonate in 70% alcohol then washed with water. The tissue is then placed in 70%

ethanol followed by sodium thiosulfate & washed with water

PICRIC ACID Remedy

Bouin’s solution

Recommended for fixation of embryos and pituitary biopsies and endometrial curettings. NOT for kidneys & abolishes feulgen’s reaction

Brasil’s Alcoholic Picformol

excellent for glycogen

Hollande’s solution

for GIT biopsies & endocrine tissues

GLACIAL ACETIC ACID

A compound fixative, recommended for nucleoproteins. Solidifies at 17°C & contraindicated for cytoplasmic fixation

TRICHLOROACETIC ACID /TCA

Often used in combination with other fixatives to produced compound fixatives

ACETONE

Can fixed and also dehydrate tissues at the same time

ACETONE

It is used at ice cold temperatures negative 5-4°C

ACETONE

Recommended for preservation of enzymes such as lipases and phosphatases & for fixing brain tissues for the diagnosis of rabies

ACETONE

Disadvantages: Dissolves fats, evaporates easily, use as raw material in making shabu

ALCOHOL FIXATIVES

Rapidly denatures and precipitates proteins

ALCOHOL FIXATIVES

Ideal for small tissue fragments

Methyl alcohol (100%)

for fixing wet and dry smears, blood smears and BM tissues

Isopropyl (95%)

recommended for touch preparations

Ethyl Alcohol (70-100%)

for blood, tissue films and smears

Carnoy’s

Most rapid fixative and is recommended for fixing chromosomes and lymph glands

Carnoy’s

It can be used along with acetone for brain tissues for the diagnosis of rabies

Carnoy’s

It contains absolute alcohol, glacial HAC and chloroform

Newcomer’s

classified both as nuclear (preserve nuclear proteins) and histochemical fixative (preserve mucopolysaccharide)

Rossmann’s solution

CT mucins & umbilical cord

OSMIUM TETROXIDE

• Expensive and not fast acting

• Used for electron microscopy

5-10x

OSMIUM TETROXIDE Required volume is ____the volume of specimen

OSMIUM TETROXIDE

Used to fixed myelin and peripheral nerves and for processing neurological tissues

Flemming’s

most common chrome osmium acetic acid fixative, excellent for nuclear structures

Flemming’s without acetic acid

for cytoplasmic structures