Histopathology & Cytology Techniques

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Questions and Answers

What is the main focus of histopathology?

Study of blood types

Study of cell structure

Study of diseases in a given tissue or organ (correct)

Preparation of tissue sections for staining

Which type of specimen has the shortest retention period in record keeping?

Tissue blocks

Specimen (correct)

Records

Slides

What is the thickness range for sectioning in histological preparation?

1.0-2.0 mm

3.0-5.0 mm (correct)

5.0-7.0 mm

0.2-0.5 mm

Which category of cytology involves cells that have been shed from epithelial surfaces?

Exfoliative cytology Signup and view all the answers

Which method of tissue preparation is typically used for organisms?

Whole mount Signup and view all the answers

What is the purpose of teasing or dissociation in fresh tissue examinations?

To separate and observe physiological processes Signup and view all the answers

What type of specimen is typically associated with exfoliative cytology?

Ascitic fluid Signup and view all the answers

What is a disadvantage of the teasing/dissociation method in tissue examination?

Anatomical relationships are destroyed Signup and view all the answers

What is the purpose of using microincineration in tissue processing?

To identify the presence of minerals in tissue Signup and view all the answers

What thickness is generally required for whole mount preparations?

0.2-0.5 mm Signup and view all the answers

In the given formula V1C1 = V2C2, what does C1 represent?

Initial concentration of the stock solution Signup and view all the answers

Which technique involves using radioactive isotopes to determine tissue relationships?

Autoradiography Signup and view all the answers

What is the primary principle behind microwave processing in tissue preparation?

To speed up diffusion of liquids into and out of the specimen Signup and view all the answers

When preparing a solution to achieve a concentration of 25 mg/mL from a 100 mg/mL stock solution, what volume of the stock solution is needed?

50 uL Signup and view all the answers

What is a common use for enzyme histochemistry in tissue preparation?

To detect specific enzyme activities Signup and view all the answers

Why is a polarizing microscope used in the context of microincineration?

To examine mineral deposits and their properties Signup and view all the answers

What is the main role of specialized silver stains in histological preparations?

To visualize neuronal structures Signup and view all the answers

What stage follows after fixing in the steps of manual tissue processing?

Dehydration with alcohol Signup and view all the answers

What is the primary purpose of the fixation process in tissue preservation?

To kill, harden, and preserve tissue materials Signup and view all the answers

Which of the following fixatives is used for electron microscopy?

Osmic acid and glutaraldehyde Signup and view all the answers

How does fixation influence protein structure?

It renders proteins insoluble through denaturation Signup and view all the answers

What pH range is optimal for tissue fixation?

6 - 8 Signup and view all the answers

What effect does fixation have on soft tissues?

It hardens them for easier handling and cutting Signup and view all the answers

Which factor greatly influences staining after fixation?

pH of the fixation solution Signup and view all the answers

What is the impact of fixation on bacterial decomposition?

It inhibits bacterial decomposition Signup and view all the answers

At what temperature range should fixation ideally occur?

20 - 22°C Signup and view all the answers

What type of necrosis is characterized by the complete destruction of the cell due to enzymatic dissolution?

Liquefaction necrosis Signup and view all the answers

Which type of necrosis involves the destruction of adipose tissue, often associated with pancreatic degeneration?

Fat necrosis Signup and view all the answers

Gangrene is primarily caused by which combination of factors?

Ischemia and bacterial infection Signup and view all the answers

What is the result of dry gangrene in terms of tissue appearance?

Mummification of the tissue Signup and view all the answers

Which of the following diseases is associated with caseous necrosis?

Tuberculosis Signup and view all the answers

Who is recognized as the Father of Medicine?

Hippocrates Signup and view all the answers

What does the Medical Technologists' Prayer emphasize in relation to caring for the sick?

Recognizing evidence of physical changes Signup and view all the answers

Which type of necrosis is specifically related to bacterial infection following ischemic injury?

Wet gangrene Signup and view all the answers

What is the primary advantage of using a 2.5% fixative for small tissue fragments?

It preserves cellular structures. Signup and view all the answers

Why is mercuric chloride considered a common fixative?

It penetrates and hardens tissues rapidly. Signup and view all the answers

What happens to the tissues when glacial acetic acid is used as a fixative?

It significantly swells collagen-containing tissues. Signup and view all the answers

What major disadvantage is associated with picric acid as a fixative?

It is highly explosive when dry. Signup and view all the answers

Which fixative is recommended for larger tissue samples?

4% formaldehyde solution. Signup and view all the answers

What is a key feature of using osmium tetroxide as a fixative?

It preserves fats and cytoplasmic structures. Signup and view all the answers

Acetone is especially suitable for fixing which type of tissue?

Brain tissues and rabies diagnosis. Signup and view all the answers

Which of the following is a major disadvantage of using alcohol as a fixative?

It preserves glycogen poorly. Signup and view all the answers

What property makes potassium dichromate a favorable fixative for certain types of tissues?

It preserves lipids and mitochondria. Signup and view all the answers

What characteristic is associated with the use of formal saline fixative?

It preserves nuclear and cytoplasmic structures. Signup and view all the answers

What is a common issue resulting from prolonged fixation with mercuric chloride?

It can cause the lysis of red blood cells. Signup and view all the answers

What is a notable disadvantage of using heat as a fixation method?

It causes significant tissue shrinkage. Signup and view all the answers

Which fixative is known for causing hemolysis of red blood cells?

Ethanol. Signup and view all the answers

Study Notes

Histopathology & Histotechniques

Histopathology studies diseases in tissues and organs.
Histotechniques prepare tissues for microscopic study, identifying them as malignant or benign.

Record Keeping & Specimen Retention

Specimen retention: 1 month to 1 year.
Tissue block retention: 3 to 10 years.
Slides are kept indefinitely.
Records and result forms are permanent. Result forms are kept in triplicate.

Types of Histological Preparation

Whole mount: Used for organisms; 0.2-0.5 mm thickness.
Sectioning: Most common preparation method; 3.0-5.0 mm thickness.
Smearing: For blood, bone marrow, and bodily fluids; used in cytological examination.

Diagnostic & Exfoliative Cytology

Diagnostic cytology: Microscopic cell examination for diagnosis.
Exfoliative cytology: Microscopic study of cells shed from epithelial surfaces (e.g., ascitic fluid, CSF, urine, sputum). Includes epithelial and mucous membrane samples. Fine needle aspiration (FNAB) is a type of diagnostic cytology.

Fresh Tissue Examinations

Teasing/Dissociation: Also known as dissection or separation. Uses normal saline solution (0.85-0.90% NaCl). Examined stained (bright field/light microscopy) or unstained (phase-contrast microscopy). Disadvantage: destroys anatomical relationships.
Coagulation: Rapid cytoplasm coagulation by intracellular enzymes (e.g., anemic or ischemic infarction).
Liquefaction/Colliquative: Rapid enzymatic cell dissolution (e.g., bacterial infection).
Fat: Adipose tissue destruction (e.g., pancreatic degenerations).
Caseous: Mixture of coagulated protein and fat (e.g., syphilis, tularemia, lymphogranuloma).
Gangrenous: Massive tissue death from ischemia and bacterial infection (necrosis plus putrefaction).

Gangrene

Massive tissue death from bacterial infection and anoxia.
Dry gangrene: Caused by arterial occlusion; ischemic necrosis and mummification (e.g., arterial embolism).
Wet gangrene: Caused by venous occlusion; bacterial infection supervenes on ischemic injury (e.g., toxemia, bacterial infection).

Historical Perspectives (Medical Technology)

Hippocrates: Father of Medicine.
Dr. Jesse Umali: First BSMT graduate.
Mr. Crisanto Almario: Father of PAMET (Philippine Association of Medical Technologists).

Reagent Preparation

Basic formula: V1C1 = V2C2. Example calculation provided in text showing preparation of a phenol solution.

Tissue Processing Steps (Manual)

Fixation: Kills, hardens, and preserves tissue. Effects include protein denaturation, bacterial inhibition, tissue hardening, and improved optical differentiation. Uses neutral buffered formalin saline or formaldehyde. Electron microscopy uses conjugated fixatives (osmic acid and glutaraldehyde). Factors to consider: pH (6-8), temperature (room temperature, 45°C for RNA, 65°C for DNA), and slightly hypertonic osmolality.

Types of Fixatives (According to Composition)

(Further details on types of fixatives are cut off in the provided text)

Metallic Fixatives: Mercuric Chloride

Most common fixative; rapidly penetrates and hardens tissues.
Excellent for nuclear detail and trichrome staining; choice for tissue photography.
Causes shrinkage, RBC lysis, removes iron from hemosiderin; slow penetration (2-5mm thickness).
Fine detail of nuclear components, greater affinity to acid dyes.
Recommended for renal tissues, connective tissues, muscles, and fibrin.
Forms black granular deposits in tissues; corrosive to metals; reduces glycogen.

Metallic Fixatives: Potassium Dichromate & Chromic Acid

Potassium dichromate: 3% aqueous solution; preserves lipids and mitochondria (pH 4.5-5.2). Does not precipitate cytoplasmic structures; adequately preserves CHO.
Chromic acid: 1-2% aqueous solution; precipitates all proteins; strong oxidizing agent.

Lead Fixative

4% aqueous solution; recommended for acid mucopolysaccharide; fixes connective tissue mucin.
Forms insoluble lead carbonate on prolonged standing (removed by filtration or acetic acid).

Picric Acid

Excellent and stable fixative for glycogen demonstration; penetrates well, fixes small tissues rapidly.
Yellow stain prevents overlooking small fragments; allows brilliant trichrome staining.
Causes RBC hemolysis; not suitable for frozen sections; prolonged fixation causes hardness.
Picrates form upon protein (never wash in water before dehydration); produces excessive staining.
Highly explosive when dry; dissolves and alters lipids; interferes with Azure Eosin staining.

Glacial Acetic Acid

Used with other fixatives; fixes and precipitates nucleoproteins, chromosomes, and chromatin.
Causes tissue swelling (collagen-containing substances); contraindicated for cytoplasmic fixation (destroys mitochondria and Golgi bodies).
When combined with potassium dichromate, lipid-fixing properties are destroyed.

Acetone

Used ice-cold (-5°C to 4°C); recommended for water-diffusible enzymes (phosphatases and lipases).
Used for brain tissue and rabies diagnosis; dissolves fat; preserves glycogen poorly.
Evaporates rapidly; used as a solvent for certain metallic salts (freeze substitution).

Alcohol Fixatives (Methanol & Ethanol)

Rapidly denatures and precipitates proteins; both fixative and dehydrating agent.
Methanol: excellent for dry and wet smears, blood, and bone marrow tissues; slow penetration; overhardening if fixed >48 hours.
Ethanol (70-100%): preserves glycogen (but doesn't fix it), nucleoproteins, and nucleic acids. Lower concentrations cause RBC hemolysis and inadequate WBC preservation. Hemosiderin preservation is less than in buffered formaldehyde.

Osmium Tetroxide/Osmic Acid

Pale yellow powder; strong oxidizing solution; precipitates and gels proteins.
Preserves fats, lipids, cytoplasmic structures (Golgi bodies and mitochondria), myelin, and peripheral nerves.
Used for ultrathin sectioning in electron microscopy (EM); expensive; poor penetration.
Irritant to eyes; inhibits hematoxylin stain; extremely volatile.

Heat Fixation

Thermal coagulation of tissue proteins; better fixation than chemical methods.
Preserves both nuclear and cytoplasmic details; suitable for frozen tissue preparations and bacteriological smears.
Causes considerable shrinkage and distortion; destroys RBCs; dissolves starch and glycogen.

Compound Micro-Fixatives: 10% Formal Saline

Simple fixative; composition: saturated formaldehyde (40g by wt).
Penetrates and fixes tissue evenly; preserves both microanatomical and histological detail.
Slow fixative; tissue tends to shrink with alcohol dehydration.

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Description

This quiz covers essential concepts in histopathology and histotechniques, focusing on the preparation of tissues for microscopic study and the methods of specimen retention. It also explores the types of histological preparations and the different aspects of diagnostic and exfoliative cytology. Test your knowledge on these critical subjects in the field of pathology.