Farrant's Medium Quiz and Flashcards

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Questions and Answers

What is the primary reason for not shaking or stirring the melted medium?

To avoid contamination of the medium

To prevent the growth of microorganisms

To ensure uniform heating of the medium

To prevent the formation of air bubbles (correct)

What is a characteristic of Farrant's medium that sets it apart from other mediums?

It solidifies upon storage

It does not solidify upon storage (correct)

It requires heating before use

It is highly viscous

What is the purpose of adding potassium acetate to Farrant's medium?

To raise the pH of the medium (correct)

To lower the pH of the medium

To improve the preservative properties of the medium

To increase the refractive index of the medium

What is the primary use of Apathy's medium?

For mounting nerve preparations Signup and view all the answers

What is the pH of Apathy's medium?

Near 4.0 Signup and view all the answers

What is the substitute for sodium merthiolate in Farrant's medium?

Arsenic trioxide Signup and view all the answers

Which of the following mounting media is generally suitable for all enzymatic label/chromogen combinations and fluorescent labels?

Aqueous mounting medium Signup and view all the answers

What is the effect of glycerol on phycobiliprotein fluorescent intensity labels?

Quenches the staining Signup and view all the answers

What is the result of exposing most fluorescent labels to excitation light?

Diminished staining Signup and view all the answers

What is the alternative to glycerine jelly for fluorescent labels?

Polyvinyl alcohol Signup and view all the answers

What is the purpose of adding paraphenylene-diamine to Polyvinyl alcohol?

As an antifading agent Signup and view all the answers

What is the method to recover a broken slide?

All of the above Signup and view all the answers

What is the purpose of adding potassium acetate, calcium chloride, or sodium chloride to a medium?

To raise the pH to near 7.0 and prevent 'bleeding' of metachromatic stains for amyloid Signup and view all the answers

What type of resin is used for embedding undecalcified bones and for electron microscopy?

Synthetic resin Signup and view all the answers

What is the main advantage of using Brun's fluid for mounting frozen sections?

It sets quite hard and does not require ringing Signup and view all the answers

What is the recommended mounting medium for frozen sections from water?

Brun's fluid Signup and view all the answers

What is the refractive index of Canada balsam?

1.524 Signup and view all the answers

How is Canada balsam usually dissolved?

In xylene in an incubator at 37°C Signup and view all the answers

Study Notes

Farrant's Medium

Formula: gum arabic 50 gm, distilled water 50 ml, glycerol 50 ml, sodium merthiolate 0.025 gm
Does not solidify upon storage and does not need to be heated before use
Takes a longer time to harden and may require ringing
Arsenic trioxide can be used as a substitute for sodium merthiolate for preservation
Adding 50 gm potassium acetate produces a neutral (pH 7.2) medium with a refractive index of 1.44

Apathy's Medium

Formula: gum arabic 50 g, pure cane sugar or sucrose 50 g, distilled water 50 mL, thymol crystals 0.05 g
Used for methylene blue-stained nerve preparations and as a general-purpose aqueous mountant
One of the most useful aqueous mountants for fluorescent microscopy, being virtually non-fluorescent
pH of the medium is near 4.0 (highly acidic), causing stains to fade or bleed into the medium
Not compatible with normal histological stains

Mounting Media for Immunocytochemical Staining

Aqueous mounting media are generally suitable for all enzymatic label/chromogen combinations and fluorescent labels
Must not contain glycerol, as it quenches the staining phycobiliprotein fluorescent intensity labels
Polyvinyl alcohol is an alternative for glycerine jelly, commonly used for fluorescent labels

Broken Slides

Mounting a broken slide onto another clean xylene-moist slide with a drop of mounting media may be sufficient for immediate examination
Incubating the slide at 37°C until the mountant is removed, then covering it with a mixture of butyl acetate and durofix can fix the section

Brun's Fluid

Formula: glucose 24 g, glycerine 6 mL, spirits of camphor 6 mL, distilled water 84 mL
Recommended for mounting frozen sections from water
Frozen sections that are mounted directly from water or paraffin sections which require dehydration and clearing should be mounted on glycerin, gum syrup, or Brun's fluid

Resinous Mounting Media

Used for sections of tissue embedded in plastic compounds (such as epoxy resins)
Can be successfully mounted in liquid resin of the same type
Divided into natural and synthetic resins
Synthetic resins are used for embedding undecalcified bones and for electron microscopy

Canada Balsam

Natural resin extracted from the Canadian tree, Abus Balsamea
Dissolved in xylene in an incubator at 37°C or paraffin oven at 58 °C, and filtered
Obtaining the desired consistency by controlled evaporation of the solvent

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Description

Learn how to prepare Farrant's Medium, a mixture used in laboratory settings. Understand the ingredients, ratios, and steps involved in creating this medium, and why it's important to avoid air bubbles.