Museum Techniques: Introduction to the museum with emphasis on the importance of the museum. Reception, fixation, and processing of various museum specimens. Cataloging of museum specimens. Introduction to autopsy technique. Care and maintenance of autopsy area, and autopsy instruments. Handling of Dead Bodies and various Uses of autopsy. Unit III

Haryana State Board of Technical Education (HSBTE): DMLT

Museum Techniques

Museum technique in histology preserves, stores, and displays histological specimens. The goal is to maintain the structural integrity of tissues for long-term study.

Importance of Museums in Histology:

• 1. Preservation of Histological Specimens: Tissues and cellular structures are maintained in a stable condition during storage.

• 2. Educational Resource: Museums are educational resources in the field of histology. They provide a platform for students, and researchers, for a deeper understanding of cellular structures, tissues, and their functions.

• 3. Research and Scientific Discovery: Researchers examine these specimens contributing to advancements in medical science.

• 4. Historical Documentation: Histological specimens in museums often have historical significance, representing milestones in medical research, disease understanding, or surgical techniques.

• 5. Public Outreach and Awareness: Medical museums serve as platforms for disseminating knowledge about the human body, health, and medical advancements.

• 6. Inspiration for Medical Professionals: Histological specimens in museums details of human anatomy. Medical students, practitioners, and researchers develop interests from these to continue their studies and careers.

Reception, fixation, and processing of various museum specimens

The reception, fixation, and processing of museum specimens are important steps. They ensure the preservation and longevity of artifacts, biological specimens, and other items housed within a museum. Each phase involves specific techniques to maintain their integrity and enhance their longevity.

Reception

• 1. Documentation and Cataloging: Each specimen undergoes careful documentation upon arrival. Details such as origin, date of acquisition, condition, and any known historical or cultural significance are recorded. Cataloging ensures organized management and recovery of information.

• 2. Condition Assessment: Specimens are carefully examined for any signs of damage, deterioration, or pest invasion. This assessment guides curators and conservators in determining the appropriate treatment and conservation measures needed.

• 3. Quarantine: Specimens undergo a quarantine period to prevent the introduction of pests or diseases to the museum collection. This is particularly crucial for biological specimens.

Fixation

Chemical Fixation (For Biological Specimens): Chemical fixation stops decomposition and preserves cellular structures of biological specimens. Various fixatives are used in this process. Each serves specific purposes in the preservation of different biological materials. Formalin, ethanol, or other fixatives are commonly used to stabilize proteins and prevent microbial degradation. The following are some Common Fixatives in Histological Museums:

Normally 10% v/v saline is used as the primary fixative. Then the specimen is transferred to a special fixative.

• 1. Formalin: A solution of formaldehyde gas dissolved in water. Formalin is the most widely used fixative in histology. It cross-links proteins preserves cellular structures and prevents autolysis or decay.

• 2. Bouin's Solution: A mixture of formaldehyde, picric acid, and acetic acid. Bouin's solution is particularly useful for preserving delicate structures, such as those found in embryos. The picric acid enhances the fixative action and provides yellow staining.

• 3. Carnoy's Solution: A mixture of chloroform, ethanol, and glacial acetic acid. Carnoy's solution is known for preserving both cellular structures and chromatin. It is used in cytological preparations.

• 4. Zenker's Fixative: A mixture of mercuric chloride, potassium dichromate, and acetic acid. Zenker's fixative is suitable for preserving tissues with a high glycogen content. It is used in the fixation of liver specimens.

• 5. Glutaraldehyde: It is an aldehyde compound. Glutaraldehyde is commonly used in electron microscopy. It provides excellent preservation of cellular ultrastructure and is especially useful for visualizing membranes.

Kaiserling proposed museum techniques in 1897. Three different solutions are used in the original techniques. These are

• 1. Kaiserling’s fluid-I: It is a fixing solution. Its components are

  • Formalin 400 mL,

  • Potassium Nitrate 30 gm

  • Potassium Acetate 60 gm

  • Tap water filtered 2,000 mL.

• 2. Kaiserling’S fluid-II:. It contains 80% v/v ethyl alcohol. It is for restoring color in an emergency.

• 3. Kaiserling’s fluid-III: It is mounting media for the biological specimen Its components are

  • Glycerine 300 mL

  • Sodium Acetate 100 gm

  • Formalin 5 mL

  • Tap water filtered 1000 mL.

Steps in Chemical Fixation

• 1. Immersion in Fixative: The biological specimen is immersed in the chosen fixative. The fixative penetrates the tissues and reacts with cellular components.

• 2. Fixation Time: The duration of fixation depends on the size and type of the specimen. Small samples may require shorter fixation times to prevent over-fixation and tissue hardening.

• 3. Temperature Control: Maintaining a consistent temperature during fixation is crucial. Cold temperatures slow down fixation. Higher temperatures accelerate the process.

• 4. Post-Fixation Rinses: After the fixation period, the specimen is often rinsed to remove excess fixative. This step is crucial to prevent artifacts and ensure compatibility with subsequent processing steps.

Precautions in fixation:

• 1. Allow entry of only an adequate amount of fixative into the biological specimen

• 2. Wash blood on biological specimens before and after fixation using formal saline.

• 3. Fix fresh soft specimens individually.

• 4. Specimens contaminated with bile must be fixed and stored separately.

Processing of museum specimen

• 1. Dehydration: Gradually replacing water with a series of increasing concentrations of alcohol or other solvents is called dehydration. This step is crucial to prevent shrinking or distortion during biological specimen processing steps

• 2. Embedding: Embed Biological specimens in a solid medium (such as paraffin or resin). It provides support for thin sectioning. This facilitates microscopic examination without damaging the specimen's delicate structures.

• 3. Sectioning: Thin sections of specimens are cut using specialized tools, such as microtomes. This step is essential for microscopic analysis and is particularly common in histological preparations.

• 4. Mounting: Sections or whole specimens are mounted on slides or in display cases. Proper mounting ensures stability and visibility.

Precautions in mounting: Follow the following precautions before mounting.

• · Remove irregular surfaces present on the biological specimen.

• · Trim the outer biological edge of the specimen.

• · Remove cotton wool from the specimen and fill arsenious acid gelatine in cavities.

• · Cover the friable specimen with a thin layer of arsenic acid gelatine.

• Soak bile stained specimen in a saturated solution of calcium chloride for 24 hours.

• 5. Labeling: Label each biological specimen with essential information, including its catalog number, origin, date, and any relevant details. Proper labeling is crucial for accurate record-keeping and traceability.

Cataloguing of museum specimen

Cataloging of histology specimens in museums involves the systematic organization and documentation of histological materials. Histology specimens consist of thin sections of tissues that have been stained and mounted on slides for microscopic examination. Proper cataloging is essential for effective management, research, and retrieval of these specimens. The following steps are involved in cataloging histology specimens in the museum:

• 1. Accessioning: Accessioning is the allotment of a unique number for each item and recording information about this item. The unique number allotted is called the accession number.

• 2. Documentation: Record detailed information about the histology specimen, including the type of tissue, species, organ or structure, and any specific characteristics.

• Include information about the preparation techniques used, staining methods, and any additional processing steps.

• 3. Photography: Capture high-quality images of the histology specimen. These images can be valuable for research, education, and outreach activities.

• Link the images to the specimen's catalog record for easy reference.

• 4. Labeling: Affix a unique accession number (catalog number) to the slide or specimen container and ensure that it is visible.

• Include additional labels on the slide or specimen container with essential information such as the tissue type, staining method, and date of preparation.

• 5. Storage: Properly store histology specimens to prevent damage or deterioration.

• Implement a systematic storage system, such as organizing specimens by accession number or tissue type. This helps to facilitate locating specimens easily.

• 6. Database Entry: Enter all relevant information into a museum database or collections management system. This database should be searchable and capable of linking related records.

• 7. .Condition Reporting: Regularly assess the condition of histology specimens and update records.

• Implement measures to preserve the integrity of the specimens.

• 8. Accessibility: Ensure that catalog information is easily accessible to museum staff, researchers, and other stakeholders. This can be achieved through a user-friendly database interface or cataloging system.