Introduction to Fresh Tissue Examination

Removing calcium or lime salts from tissues after fixation.

Recommended fluid-to-tissue ratio for decalcification is 20:1.

Fastest decalcifying agent. However, it affects staining and can damage tissues.

Recommended for autopsy materials, bone marrow, and cartilage decalcification.

Slow-acting, weak decalcifying agent suitable for small bone pieces.

Can be used as both a fixative and a decalcifying agent, used for minute bone specimens.

Excellent for nuclear and cytoplasmic staining, but is slow.

Use 10% aqueous Nitric Acid Solution or Formol-Nitric Acid for rapid decalcification, ideal if diagnosis needs to happen quickly(24 hrs or less)

The process of removing calcium salts from tissues after fixation, allowing for proper sectioning and staining.

Several factors influence decalcification speed, including concentration, volume, tissue structure, temperature, and agitation.

Ideal for decalcifying autopsy materials, bone marrow, and cartilage due to its gentler nature.

A powerful dehydrating agent that also acts as a clearing agent, but can be toxic and expensive.

Dehydrates tissue rapidly, allowing for storage for months. It is directly usable after water or saline.

Used to dehydrate tissue sections and smears after staining, minimizing shrinkage. This gentler method is ideal for delicate preparations.

Methods to assess the extent of decalcification include physical, x-ray, and chemical tests. Each has its strengths and weaknesses.

Cloudiness in decalcification indicates incomplete decalcification. The tissue has not been fully treated to remove calcium salts, leaving it opaque.

Dehydration removes water from the tissue, replacing it with alcohol. This prepares the tissue for embedding in wax, preventing tissue shrinkage and distortion.

Clearing is the process of replacing alcohol with a solvent that is miscible with both alcohol and paraffin. This allows the paraffin to penetrate the tissue.

Xylene is a colorless clearing agent, highly miscible with alcohol and paraffin. It's cheap, commonly used for celloidin sections, and accelerates dehydration.

If xylene turns milky when a tissue is immersed, it means the tissue was not fully dehydrated. Water remains in the tissue, causing the xylene to become cloudy.

Toluene can be used as an alternative clearing agent to xylene and benzene. It's suitable for blood and tissue smears and is miscible with alcohol and paraffin.

A good clearing agent must be miscible with water, paraffin, and mounting medium. It should also be able to remove alcohol from the tissue and allow paraffin to penetrate.

Choosing the right clearing agent depends on the type of tissue, the intended use, and the budget. Factors like clearing speed, safety, and compatibility are important.

A staining method where a dye solution directly colors the tissue elements.

A staining method where a dye's action is intensified by adding a mordant, acting as a bridge between dye and tissue.

A substance used in indirect staining to enhance the dye's action by forming a link between the dye and the tissue.

A substance that speeds up the staining reaction, making the process faster.

A technique where tissues are treated with metallic salts, which are reduced by the tissue creating a dark deposit.

A staining technique used to visualize the structures of living cells.

A staining technique where dye is injected into a living animal to stain cells.

A staining technique where cells are stained immediately after being removed from a living organism.

A chemical that helps hematoxylin dye adhere to tissue structures, improving staining intensity and permanence.

A process of oxidizing hematoxylin to increase its staining ability.

A type of hematoxylin that is ripened by sodium iodate, often used for routine staining.

A hematoxylin that is ripened using mercuric oxide, known for its strong staining properties.

A type of hematoxylin used for photomicrography, where it enhances contrast and detail.

An iron hematoxylin solution that uses ferric ammonium chloride as a mordant.

Transparent solutions used to permanently mount tissue sections on slides for microscopic observation.

A popular aqueous mounting medium that does not require heating before use. It provides a semi-permanent mount.

Picrocarmine is a stain used in neuropathological studies for demonstrating glycogen and nerve preparations.

Sudan Black is a lysochrome (oil-soluble dye) known for its high affinity for phospholipids, making it very sensitive in detecting them.

Brün's Fluid is a mounting medium specifically designed for frozen sections.

Canada Balsam is a natural resin extracted from the Abies Balsamea tree.

DPX, a mounting medium, is recommended for small tissue sections but not whole mounts due to potential shrinkage during drying.

XAM is a synthetic resin mixture that dries quickly without retracting and preserves stains well.

Clarite is a resin soluble in xylene with a refractive index of 1.544.

Synthetic dyes, often called 'coal tar dyes', are derived from hydrocarbon benzene and are collectively known as aniline dyes.