Rotary Microtome Disadvantages and Care
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Questions and Answers

What is a disadvantage of using a rotary microtome?

  • It is suitable for cutting large blocks
  • It is relatively inexpensive
  • It has a complex design (correct)
  • It is easy to operate

    • What should you use to avoid danger when operating a rotary microtome?

  • A knife guard/protector (correct)
  • A soft brush
  • Xylol
  • Paint

    • How should you clean the metal parts of a rotary microtome?

  • With xylol (correct)
  • With a soft brush
  • With water
  • With oil

    • Why should you avoid continuous application of xylol to a rotary microtome?

    <p>It can remove the paint</p> Signup and view all the answers

    What is the purpose of covering a rotary microtome when not in use?

    <p>To prevent accumulation of dust and dirt</p> Signup and view all the answers

    Which type of microtome is used for cutting hard and brittle materials?

    <p>Saw microtome</p> Signup and view all the answers

    What is the purpose of the face plate in the rotary microtome?

    <p>To guide the ribbons away from the blade and towards the operator</p> Signup and view all the answers

    What is the function of the cassette clamp or block holder?

    <p>To hold the paraffin block in place</p> Signup and view all the answers

    What is the purpose of the coarse hand wheel?

    <p>To move the block holder towards or away from the knife</p> Signup and view all the answers

    What is the range of micron settings for section thickness on most microtomes?

    <p>1-60 microns</p> Signup and view all the answers

    Why should the water bath be cleaned every day?

    <p>To avoid microorganisms growth</p> Signup and view all the answers

    What is the recommended temperature for the water bath?

    <p>56°C or just below the melting point of paraffin wax</p> Signup and view all the answers

    Why should paraffin blocks be placed on a cold surface?

    <p>To harden the cut surface</p> Signup and view all the answers

    What is the function of the advancement hand wheel?

    <p>To turn in one direction and advance the block towards the knife at the specified microns</p> Signup and view all the answers

    What is the name of the inventor of the rotary microtome?

    <p>Professor Minot</p> Signup and view all the answers

    What is the range of thickness of sections that can be cut by a semi-automated rotary microtome?

    <p>0.5 to 2.0 um</p> Signup and view all the answers

    What is the purpose of the retracting action in a rotary microtome?

    <p>To move the tissue block away from the knife</p> Signup and view all the answers

    What is the function of the block adjustment screw in a rotary microtome?

    <p>To hold the tissue block in place</p> Signup and view all the answers

    What is the purpose of the thickness gauge in a rotary microtome?

    <p>To measure the thickness of the section</p> Signup and view all the answers

    What is the recommended angle between the blade edge bevel and the block?

    <p>2-5 degrees</p> Signup and view all the answers

    What type of rotary microtome has two motors that drive both the fine and coarse advance hand-wheel?

    <p>Fully automated</p> Signup and view all the answers

    What is the function of the knife holder base in a rotary microtome?

    <p>To anchor the knife holder to the microtome stage</p> Signup and view all the answers

    What is the purpose of trimming the edges of the block with a sharp razor blade?

    <p>To ensure the upper and lower edges of the block are parallel to the edges of the knife</p> Signup and view all the answers

    What is the name of the platform that has rails that secure the knife holder base in a rotary microtome?

    <p>Microtome base plate</p> Signup and view all the answers

    How should the block be oriented on the cassette holder?

    <p>So that its greater axis is perpendicular to the edge of the knife</p> Signup and view all the answers

    What is the recommended section thickness for coarse cutting?

    <p>15 microns</p> Signup and view all the answers

    Why should xylene not be used to clean the paraffin debris from the knife?

    <p>It can leave an oily remnant on the knife</p> Signup and view all the answers

    What should be done after coarse cutting the block?

    <p>Return the block to the cold plate for 1-2 minutes</p> Signup and view all the answers

    What is the recommended section thickness for final sectioning?

    <p>4-5 microns</p> Signup and view all the answers

    Why should the microtome hand-wheel be locked?

    <p>To prevent accidental movement of the block</p> Signup and view all the answers

    What is the purpose of breathing on the paraffin sections?

    <p>To flatten the sections and eliminate static electricity</p> Signup and view all the answers

    How many sections are typically included in a ribbon?

    <p>4-5 sections</p> Signup and view all the answers

    What is used to gently separate the floating sections on the water bath?

    <p>Both A and B</p> Signup and view all the answers

    Why are slides stored at room temperature after cutting?

    <p>To prevent drying of the sections</p> Signup and view all the answers

    What is the range of section thickness that can be achieved with a rotary microtome?

    <p>1.0 - 60.0 µm</p> Signup and view all the answers

    What is an advantage of using a rotary microtome?

    <p>It is ideal for cutting serial sections</p> Signup and view all the answers

    How are slides typically dried after cutting?

    <p>Horizontally on a warm plate for 10 min</p> Signup and view all the answers

    What type of pens should be avoided when labeling slides?

    <p>All of the above</p> Signup and view all the answers

    Study Notes

    Disadvantages of Rotary Microtome

    • Complex design
    • Higher initial cost
    • Knife is placed in the blade holder up position and can be dangerous to the operator (can be avoided with knife guard/protector)
    • Not suitable for cutting large blocks

    Care of the Rotary Microtome

    • Brush away accumulated paraffin and tissue with a soft brush after cutting
    • Wipe clean all metal parts with xylol
    • Avoid continuous application of xylol to the rest of the machine (can remove the paint)
    • Dry the machine carefully, especially the knife holder
    • Keep the machine well oiled to prevent rust formation
    • Keep the moving parts of the microtome lubricated
    • Cover the microtome when not in use to prevent accumulation of dust and dirt

    Types of Microtomes

    • Saw microtome: for hard materials (e.g., bone, brittle material), thickness > 30 microns
    • Sledge microtome: for embedded hard samples, thickness 1-60 microns, for bony samples sliced for histo-enzymes study
    • Rotary microtome: for thin samples, most widely used, also called Minot microtome

    Rotary Microtome

    • Mechanism: hand wheel rotates through 360 degrees, moving the specimen vertically past the cutting surface (i.e., knife edge) and returning it to the starting position
    • Block holder is mounted on a steel carriage which moves up and down in grooves and is advanced by a micrometer screw - cutting perfectly flat sections
    • Types: manual, semi-automated, fully automated

    Rotary Microtome: Types

    • Manual: completely manipulated by the operator
    • Semi-automated: auto cut microtome with built-in motor drive, foot and hand control, suitable accessories can cut thin sections of 0.5 to 2.0 um thickness
    • Fully automated: two motors drive both the fine and the coarse advance hand-wheel, e.g., automated cryostate

    Rotary Microtome Parts

    • The main components of a rotary microtome are:
      • Base
      • Cassette or block holder
      • Block adjustment screw
      • Knife holder
      • Blade clamps
      • Angle of tilt adjustment
      • Thickness gauge
      • Operating handle
      • Face plate
      • Waste tray

    Rotary Microtome Parts (continued)

    • Microtome base plate or stage: a platform with rails that secure the knife holder base
    • Knife holder base: a part that anchors the knife holder to the microtome stage
    • Knife holder: comprised of the blade clamp, knife tilt, and face plate
    • Cassette clamp or block holder: holds the paraffin block in place, moves up and down with each revolution while the blade is stationary
    • Coarse hand wheel: moves the block holder toward or away from the knife
    • Advancement hand wheel: turns in one direction and advances the block toward the knife at the specified microns
    • Micron adjustment: micron settings for section thickness
    • Thickness gauge: micron settings for section thickness
    • Base on which the whole microtome rests

    Rotary Microtome: Operation

    • Fitting and adjusting the knife:
      • Install a disposable blade in the microtome
      • Set angle between the blade edge bevel and the block to 2-5 degrees (clearance angle)
      • Lock the blade in place
      • Lock the microtome hand-wheel
    • Trimming:
      • Trim the edges of one block with a sharp razor blade
      • Fit the cassette paraffin block onto the cassette holder of the microtome
    • Sectioning:
      • Advance the block until it is in contact with the edge of the knife
      • Set the section thickness around 15 microns
      • Coarse cut the block at 15 microns until the whole surface of the embedded tissue can be cut
      • Return the trimmed block to the cold plate for 1-2 min
      • Set the section thickness to 4-5 um
      • Remove wax debris from the knife with alcohol
      • Move to an unused area on the blade or install a new disposable blade
    • Section collection:
      • Transfer the cut sections to the surface of the water bath
      • Gently separate the floating sections on the water bath with pressure from the tips of forceps to remove fine wrinkles
      • Collect sections on a clean glass slide

    Advantages of Rotary Microtome

    • Section thickness range: 1.0 - 60.0 µm
    • Stable and less of vibration (heavier and more stable)
    • Excellent for routine and research work
    • Ability to cope with harder tissue
    • Easy adaptation to all types of tissues (hard, fragile, or fatty)
    • Ideal for cutting serial sections
    • Cutting large blocks
    • Cutting angle of knife is adjustable
    • Large and heavier knife used - less vibration when cutting hard tissue
    • Technological advances in automation improved section quality, increased productivity, and occupational safety

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    Related Documents

    Rotary Microtome Parts PDF

    Description

    Learn about the drawbacks of using a rotary microtome, including its complex design and initial cost, as well as how to properly care for the machine.

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