Leder Esterase

for Mast Cells

steps

materials

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Materials

Pararosanilin

Material	Amount
Pararosanilin	0.5	g
Distilled water	20	mL
Hydrochloric acid, conc.	2.5	mL

Warm gently and filter. Refrigerate.

Nitrosylated pararosanilin

Material	Amount
Pararosanilin solution	0.1	mL
Sodium nitrite, 4% aqueous	0.1	mL

The sodium nitrite solution must be fresh. After mixing, let stand for one minute. Use immediately.

Sorenson Stock A

Material	Amount
Disodium hydrogen phosphate	2.73	g
Distilled water	250	mL

Sorenson Stock B

Material	Amount
Potassium dihydrogen phosphate	2.27	g
Distilled water	250	mL

Sorenson working buffer

Material	Amount
Sorenson stock A	41	mL
Sorenson stock B	9	mL

Incubating medium

Material	Amount
Naphthol-ASD chloroacetate	10	mg
N,N-dimethyformamide	1	mL
Sorenson’s working buffer	35	mL
Nitrosylated pararosanilin	0.2	mL

Combine in the order given. Mix well, filter and use immediately.

Light green

Material	Amount
Light green SF yellowish	1	g
Distilled water	100	mL
Glacial acetic acid	1	mL

Tissue Sample

4µ paraffin sections of formalin fixed tissue are suitable.

Protocol

Bring sections to distilled water.
Place in the incubating medium for 40 minutes.
Wash in running tap water for 5 minutes.
Counterstain with light green for 30 seconds.
Wash in running tap water for 5 min.
Air dry.
Clear in xylol and mount.

Expected Results

Esterase activity (mast cells) – red
Background – green

Notes

An alternative to air drying, which avoids some of the artifact introduced, is to blot the section, then wash with xylene. This is repeated until the sections are cleared.

Safety Note

Prior to handling any chemical, consult the Safety Data Sheet (SDS) for proper handling and safety precautions.

References

Leder, L.D. (1964)
Klinische Wochenschrift

Leder Esterase for Mast Cells