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    Diagnostic Cytology Methods and Purpose: de Vera, Jim Ericson F. March 23, 2018 Bmls Histopathology: Tue / 7:00-9:00

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    Rashedah Martin
    This document discusses various staining techniques used in cytology and histopathology. It describes simple staining methods like methylene blue and carbol fuchsin staining which involve using a single dye. Differential staining methods like Gram staining differentiate cells into groups based on cell wall characteristics. The Papanicolaou stain is a polychromatic stain crucial for cytology. It differentially stains nuclear and cytoplasmic components of cells to clearly define cell morphology for cancer screening and diagnosis.

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    Diagnostic Cytology Methods and Purpose: de Vera, Jim Ericson F. March 23, 2018 Bmls Histopathology: Tue / 7:00-9:00

    Uploaded by

    Rashedah Martin
    71 views3 pages
    This document discusses various staining techniques used in cytology and histopathology. It describes simple staining methods like methylene blue and carbol fuchsin staining which involve using a single dye. Differential staining methods like Gram staining differentiate cells into groups based on cell wall characteristics. The Papanicolaou stain is a polychromatic stain crucial for cytology. It differentially stains nuclear and cytoplasmic components of cells to clearly define cell morphology for cancer screening and diagnosis.

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    This document discusses various staining techniques used in cytology and histopathology. It describes simple staining methods like methylene blue and carbol fuchsin staining which involve using a single dye. Differential staining methods like Gram staining differentiate cells into groups based on cell wall characteristics. The Papanicolaou stain is a polychromatic stain crucial for cytology. It differentially stains nuclear and cytoplasmic components of cells to clearly define cell morphology for cancer screening and diagnosis.

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    71 views3 pages

    Diagnostic Cytology Methods and Purpose: de Vera, Jim Ericson F. March 23, 2018 Bmls Histopathology: Tue / 7:00-9:00

    Uploaded by

    Rashedah Martin
    This document discusses various staining techniques used in cytology and histopathology. It describes simple staining methods like methylene blue and carbol fuchsin staining which involve using a single dye. Differential staining methods like Gram staining differentiate cells into groups based on cell wall characteristics. The Papanicolaou stain is a polychromatic stain crucial for cytology. It differentially stains nuclear and cytoplasmic components of cells to clearly define cell morphology for cancer screening and diagnosis.

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    © All Rights Reserved
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    of 3

    De Vera, Jim Ericson F.

    March 23, 2018


    BMLS Histopathology: Tue / 7:00-9:00

    Diagnostic Cytology Methods and Purpose

    Staining is technique used in microscopy to enhance contrast in the microscopic image. Stains
    and dyes are frequently used in biological tissues for viewing, often with the aid of different microscopes.
    Stains may be used to define and examine bulk tissues (highlighting, for example, muscle fibers or
    connective tissue), cell populations (classifying different blood cells, for instance), or organelles within
    individual cells.

    Staining techniques
     Direct staining - The organism is stained and background is left unstained.
     Negative staining - The background is stained and the organism is left unaltered.

    Kinds of Stains
     Simple stain
     Differential stain
     Structural or special stains

    Simple Staining
    The staining process involves immersing the sample (before or after fixation and mounting) in
    dye solution, followed by rinsing and observation. Many dyes, however, require the use of a mordant, a
    chemical compound that reacts with the stain to form an insoluble, coloured precipitate. When excess dye
    solution is washed away, the mordanted stain remains.
    Simple staining is one step method using only one dye. Basic dyes are used in direct stain and
    acidic dye is used in negative stain. Simple staining techniques is used to study the morphology better, to
    show the nature of the cellular contents of the exudates and also to study the intracellular location of the
    bacteria.

    Commonly used simple stains


     Methylene blue
     Dilute carbol fuchsin
     Polychrome methylene blue

    Loeffler’s Methylene Blue


    Method of Staining: Flood the smear with methylene blue, allow for 2 minutes, pour off the stain
    and allow the air to dry by keeping in a slanting position and by this the organism will retain the
    methylene blue stain.
    Use: Methylene blue staining is used to make out clearly the morphology of the organisms eg.
    H.influenzae in CSF, Gonococci in urethral pus.
    Polychrome Methylene Blue
    Preparation: Allow Loeffler’s Methylene blue to ‘ripen’ slowly. Methylene blue stain is kept in
    half filled bottles, aerate the content by shaking at intervals, Slow oxidation of methylene blue forms a
    violet compound and Stain gets polychrome property. The ripening nearly takes 12 months and this is
    hastened by addition of 1% potassium carbonate.
    Use: Polychrome Methylene Blue is used to demonstrate Mc Fadyean reaction of B.anthracis and
    in this the blue bacilli Is surrounded by purple capsular material.

    Dilute Carbol Fuchsin


    Preparation: Prepare carbol fuchsin and dilute it to 1/15 using distilled water Method of staining
    Flood the smear and let stand for 30 seconds, wash with tap water and blot gently to dry.
    Use: To stain throat swab from patients of suspected Vincent’s angina, (Borrelia are better
    stained), it is used as a counter stain in Gram stain and to demonstrate the morphology of Vibrio cholerae
    (comma shaped).

    Differential Staining
    Gram Staining: Differential Stains use two or more stains and allow the cells to be categorized
    into various groups or types. Both the techniques allow the observation of cell morphology, or shape, but
    differential staining usually provides more information about the characteristics of the cell wall
    (Thickness). Gram staining (or Gram’s method) is an emprical method of differentiating bacterial species
    into two large groups (Gram-positive and Gram-negative) based on the chemical and physical properties
    of their cell wall. The Gram stain is almost always the first step in the identification of a bacterial
    organism, While Gram staining is a valuable diagnostic tool in both clinical and research settings, not all
    bacteria can be definitively classified by this technique, thus forming Gram variable and Gram
    MICROBIOLOGY MODULE Common Staining Technique Microbiology 24 Notes indeterminate
    groups as well. The word Gram is always spelled with a capital, referring to Hans Christian Gram, the
    inventor of Gram staining.

    Gram Staining Technique

     Crystal violet acts as the primary stain. Crystal violet may also be used as a simple stain
    because it dyes the cell wall of any bacteria.
     Gram’s iodine acts as a mordant (Helps to fix the primary dye to the cell wall).
     Decolorizer is used next to remove the primary stain (crystal violet) from Gram Negative
    bacteria (those with LPS imbedded in their cell walls). Decolorizer is composed of an
    organic solvent, such as, acetone or ethanol or a combination of both.)
     Finally, a counter stain (Safranin), is applied to stain those cells (Gram Negative) that
    have lost the primary stain as a result of decolorization.

    Papanicolaou (PAP) Staining


    Papanicolaou stain (also Papanicolaou’s stain or PAP stain) is the most important stain utilized in
    the practice of Cytopathology. It is a polychromatic stain containing multiple dyes to differentially stain
    various components of the cells. This technique was developed by George Papanicolaou, the father of
    Cytopathology. This method is used to differentiate cells in the smear preparation of various
    gynecological specimens (pap smears), materials containing exfoliative cells and material from fine
    needle aspiration.

    Objectives of Papanicolaou Stain


    Papanicolaou described three chief objectives for staining of cytological smears:

     Definition of nuclear details : Because of the widespread muclear abnormalities of


    cancer cells and their diagnostic significance, good staining of the nucleus is of primary
    importance.
     Transparency of cytoplasm : This is of particular importance because of the varying
    thickness and the frequent overlapping of cells.
     Differentiation of cells : Differences in the staining reaction such as that between
    acidophilic and basophilic cells help greatly in the identification of certain cell types
    found in smears.

    Principle of Papanicolaou Stain


    Papanicolaou stain includes both acidic and basic dyes. Acidic dye stains the basic components of
    the cell and basic dye stain the acidic components of the cell. The polychromatic PAP stain involves five
    dyes in three solutions.

    a.) Hematoxylin : Natural dye hematoxylin is the nuclear stain which stains cell nuclei blue. It has
    affinity for chromatin, attaching to sulphate groups on the D.N.A. molecule. Harris’ hematoxylin
    is the commonest cytologically although Gills’ hematoxylin and Hematoxylin S can be used.
    b.) Orange Green 6 : This is the first acidic counterstain (cytoplasmic stain) which stains matured
    and keratinized cells. The target structures are staine d orange in different intensities.
    c.) Eosin Azure : This is the second counterstain which is a polychrome mixture of eosin Y, light
    green SF and Bismarck brown.
    d.) Eosin Y gives a pink colour to cytoplasm of mature squamous cells, nucleoli, cilia and red blood
    cells. Staining solutions commonly used in cytology are EA 31 and EA 50, while EA 65
    e.) Light green SF stains blue to cytoplasm of metabolically active cells like parabasal squamous
    cells, intermediate squamous cells and columnar cells.
    f.) Bismarck brown Y stains nothing and sometimes it is often omitted.

    Procedure of Papanicolaou Stain


    Both progressive and regressive nuclear staining techniques can be used in Papanicolaou stain.
    Before staining, Wet fixation immediately with Cytology spray fixative 96% ethanol for minimum 30 min
    is required.

    Procedure of Progressive Papanicolaou Staining Method


    In the progressive method, the nucleus is stained with hematoxylin to a intensity desired. The
    intensity of the nuclear staining is controlled by the immersion of the slide into a blueing agent. Most
    commonly used blueing agent is Sott’s tap water (pH 8.02).

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