[1S] UNIT 1.2 Instrumentation in Histopathology Flashcards
Medical Technologists are also known as
Clinical Laboratory Scientists
Overview of Different Laboratory Procedures
Numbering
Fixation
Decalcification*
Dehydration
Clearing
Impregnation
Embedding
Blocking
Trimming
Sectioning
Staining
Mounting
Labelling
A procedure in which we assign a specific code/id for a particular specimen as the cassette containing the specimen is too small to include every specific detail
Numbering/Accessioning
T/F: Numbering may be a combination of numbers and letters
T
T/F: Site numbers (different areas of an organ) are not included if several sites are used
F; may also be included
The process of preserving the tissues and its cellular constituents
Fixation
● To prevent autolysis
● For the pathologists to read clearly and correctly to get an accurate diagnosis
Fixation
Fixation reagent
Formalin
The process of removing calcium ions to soften the tissue for easier cutting
Decalcification
T/F: All specimens undergo decalcification
F; not all
Decalcification reagent
Nitric Acid
The process of removing water or excess water
Dehydration
Why is water removed in a specimen?
Excess water is removed so that infiltration is performed properly
Dehydration reagent
Alcohol
● The process of removing alcohol
● Alcohol is removed to perform Impregnation or infiltration properly
Clearing
Clearing agent
Xylene
● The process of infiltrating the tissue with solution that will fill up the natural spaces to maintain the integrity of the specimen appearance
○ This provides rigid support for the tissues
○ To maintain the appearance and shape of the tissue microscopically
Impregnation / Infiltration
Impregnation reagent
Paraffin Wax
● The process of forming tissue block using a mold
● This is needed to perform cutting on a particular site
Embedding & Blocking
● The process of removing excess wax
● _________ __________ is created so that we can prepare a tissue ribbon properly
Trimming
Truncated pyramid
The process of cutting the tissue into micro thin slices of tissue
Sectioning / Cutting
● The process of coloring the tissues to clearly identify cells clearly, correctly, and accurately
● To differentiate cell from one another
Staining
● The process of securing the slide with a coverslip (permanent)
● To protect the stained slide
● Performed to protect the slide during handling and storage
Mounting
● The process of providing a particular label
● Assigned number is also used for this process
Labelling
How many steps are in tissue processing without decalcification?
12
Characterized by the transfer of tissues, contained within a basket, through a series of stationary reagents arranged inline or in a circular carousel plan
AUTOMATED TISSUE PROCESSOR: Tissue Transfer Processors (Carousel-Type)
TISSUE TRANSFER PROCESSORS (CAROUSEL-TYPE)
● ___ reagent positions & ___ wax positions
● Capacity = __________
● 9-10 and 2-3
● 30-110 cassettes
are the instruments where sample tissue is placed
Cassettes
Characterized by processing fluids pumped to and from a retort in which the tissues remain stationary
AUTOMATED TISSUE PROCESSOR: Fluid Transfer Processors
FLUID-TRANSFER PROCESSORS
● _____ reagent stations with temperatures adjustable between ______
● ___ paraffin wax stations with variable temperature settings between ______
● Capacity: _________
● 10-12 reagent stations with temperatures adjustable between 30-45°C
● 3-4 paraffin wax stations with variable temperature settings between 48-68°C
● Capacity: 100-300 cassettes
ADVANTAGES OF USING BOTH TISSUE-TRANSFER AND FLUID-TRANSFER
T/F: Flexibility of reagent selection
T
ADVANTAGES OF USING BOTH TISSUE-TRANSFER AND FLUID-TRANSFER
T/F: The conditions and schedule are designed to provide optimum processing even for the small batches of tissues
T
TISSUE PROCESSING
Used for making tissue blocks
Tissue Embedding Center
TISSUE PROCESSING
Advantage:
○ It has a refrigeration system
■ The cold platform in the equipment
■ To solidify the tissue
■ Paraffin is solidified for the tissue to be stable
Tissue Embedding Center
TISSUE PROCESSING: TISSUE EMBEDDING CENTER
Run the tissue embedding center for about _ hours to make sure paraffin wax is melted in the paraffin chamber
5
TISSUE PROCESSING: TISSUE EMBEDDING CENTER
T/F: Not all blocking steps can be performed with the help of this machine
F; All blocking steps can be performed
EMBEDDING PROCESS
What temperature should the paraffin be and wax melting point?
61°C
55-57°C (wax melting point)
EMBEDDING PROCESS
T/F: Place cassettes in the paraffin reservoir in numerical order
T
PARTS OF THE TISSUE EMBEDDING CENTER
The cool system of the Tissue Embedding Center
Freon Refrigeration System
PARTS OF THE TISSUE EMBEDDING CENTER
Where embedded tissues, with their respected molds to hasten solidification
Cold Orientation Platform
PARTS OF THE TISSUE EMBEDDING CENTER
○ A button that provides a non clogging flow of molten paraffin for casting the mold
○ Same button just like in water dispenser
Microswitch Dispenser
PARTS OF THE TISSUE EMBEDDING CENTER
Hot orientation platform materials
Forceps
Tissue
Metal Mold
PARTS OF THE TISSUE EMBEDDING CENTER
T/F: During embedding, the orientation is provided by the pathologist
T
PARTS OF THE TISSUE EMBEDDING CENTER
○ Top left part of the machine
○ Above the cold orientation platform
○ Catches excess paraffin
Waste Drawer
PARTS OF THE TISSUE EMBEDDING CENTER
Area where we can preheat the forceps
Hot Well
Basic instrument used that is capable of cutting section at a predetermined thickness by sliding the block into a cutting tool which is fixed and attached to the machine.
Microtomy
PRINCIPLE: A spring balance teeth or pawl is brought into contact with, and turns a ratchet feed wheel connected to a micrometer screw, which in turn rotated, moving the tissue block at a predetermined distance towards the knife for cutting sections at uniform thickness.
Microtomy
KINDS OF MICROTOME
● Invented by Paldwell Trefall in 1881
● Simplest among the different types of microtome
Rocking Microtome
KINDS OF MICROTOME
● Consist of a heavy base and two arms:
● Used to cut small and large blocks of paraffin tissues.
● Not recommended for serial sections because tissues are cut in slightly curved planes
Rocking Microtome
KINDS OF MICROTOME
● Disadvantage:
○ Restrictions in size of tissue block that can be cut
○ Difficulty of reorienting the block
Rocking Microtome
KINDS OF MICROTOME
● Minot microtome
● Invented by Minot in 1885-1886
Rotary Microtome
KINDS OF MICROTOME
Most common type used for both routine and research laboratories
Rotary Microtome
KINDS OF MICROTOME
● Operated by the rotation of the flywheel
● Causes reciprocal motion of the knife over the block
● Thickness of the section being automatically regulated by the ratchet feed wheel
Rotary Microtome
ROTARY MICROTOME DIFFERENCE FROM THE ROCKING MICROTOME
T/F: The knife and the block holder are brought together by upward and vertical motions
T
ROTARY MICROTOME DIFFERENCE FROM THE ROCKING MICROTOME
T/F: Cuts sections in a perfectly flat plane
T
ROTARY MICROTOME DIFFERENCE FROM THE ROCKING MICROTOME
● Heavier and more stable
● More complex in design and construction
● More expensive
T
ROTARY MICROTOME DIFFERENCE FROM THE ROCKING MICROTOME
T/F: The blade is placed in a blade-down position which is relatively dangerous
F; blade-up
KINDS OF MICROTOME
● Developed by Adams in 1789
● Especially recommended for cutting extremely hard and rough tissue blocks
Sliding Microtome
KINDS OF MICROTOME
● The knife is moved horizontally against a fixed block which progresses against it in an inclined plane
● Most dangerous type of microtome
Sliding Microtome
KINDS OF MICROTOME
Consist of two movable pillars holding the adjustable knife clamps, allowing the knife to be set at an angle for cutting celloidin sections
Base-Sledge Microtome
KINDS OF MICROTOME
Favored in laboratories where very hard tissue or large blocks are usually sectioned
Base-Sledge Microtome
KINDS OF MICROTOME
• Suited for sectioning specimens embedded in all forms of media
• Comparatively more stable
Base-Sledge Microtome
KINDS OF MICROTOME
The block remains stationary while the knife is moved backward and forward during the process of sectioning.
Standard Sliding Microtome
KINDS OF MICROTOME
• Developed mainly for cutting celloidin-embedded tissue blocks
• Inherently more dangerous
Standard Sliding Microtome
KINDS OF MICROTOME
• Invented by Queckett in 1848
• The stage for block holder is hollow and perforated around its perimeter, attached to a reinforced flexible lead pipe thru which carbon dioxide passes from a cylinder.
Freezing Microtome
KINDS OF MICROTOME
• A simple lever operated valve allows the release of rapid intermittent burst of carbon dioxide
• A second cooling device for lowering temperature of the knife to facilitate sectioning.
Freezing Microtome
KINDS OF MICROTOME
• Used to cut undehydrated tissues in a frozen state
• When histological demonstration of fat is needed
Freezing Microtome
KINDS OF MICROTOME
• When certain neurological structures are to be
studied
• When sensitive tissue constituents to be studied are damaged or destroyed by heat.
Freezing Microtome
KINDS OF MICROTOME
• Consists of microtome kept inside a cold chamber which has been maintained at a temperature between -5 to -30°C (-20°C) by an adjustable thermostat
• Capable of freezing fresh tissues within 2-3 minutes
• Can cut sections of 4µ with ease.
FREEZING MICROTOME: Cryostat
KINDS OF MICROTOME
Provides a means of preparing thin sections of fresh frozen tissues for fluorescent antibody staining techniques or histochemical enzyme studies.
FREEZING MICROTOME: Cryostat
KINDS OF MICROTOME
Most commonly used for rapid preparation of urgent tissue biopsies for intraoperative diagnosis.
FREEZING MICROTOME: Cryostat
are used to mount tissues in the Cryotome
OCTs
KINDS OF MICROTOME
Primarily used for cutting tissue sections at 0.5 micra for electron microscopy
Ultrathin Microtome
KINDS OF MICROTOME
The knife used for cutting the ultrathin sections consists mainly of selected fragments of ______ ______ ______.
broken plate glass
KINDS OF MICROTOME: ULTRATHIN MICROTOME
The specimen used is small, fixed in ______ ________, and embedded in plastic.
osmium tetroxide
Other Kinds of Microtome
- Vibrating Microtome
- Hand Microtome
- Saw Microtome
- Laser Microtome
- Computerized Microtome
CARE OF THE MICROTOME
T/F: All the accumulated paraffin and small pieces of tissues must be brushed away with soft brush and not allowed to stay in the microtome
T
CARE OF THE MICROTOME
T/F: After drying the machine and knife holder, the parts should be wiped with xylene
F; xylol not xylene
CARE OF THE MICROTOME
T/F: Movable portions should be oiled thoroughly to prevent rusting
T
CARE OF THE MICROTOME
T/F: Microtome must always be covered when not in use
T
Trimming and section-cutting are done with a?
Microtome Knife
TYPES OF MICROTOME KNIVES
• Usually 25 mm in length
• One side of the knife is flat while the other is concave.
Plane-Concave Knife
TYPES OF MICROTOME KNIVES
• Usually 120 mm in length
• With both sides concave, recommended for cutting
paraffin embedded sections on a rotary microtome.
Biconcave Knife
TYPES OF MICROTOME KNIVES
• Usually 100 mm in length
• Have both sides straight
• Recommended for frozen sections or for cutting extremely hard and tough specimens embedded in
paraffin blocks using a base-sledge type or sliding mircrotome.
Plane-Wedge Knife
TYPES OF MICROTOME KNIVES
• Have a sharp cutting edge that can cut 2-4 µ thick sections with ease.
• Cheaper to use.
Disposable Blades
TYPES OF MICROTOME KNIVES
• Used for trimming and semi-thin sectioning of tissue blocks for electron microscopy.
• Commercially prepared
• Should be prepared and stored in dust-free boxes with lids, just before use, to avoid contamination.
Glass Knives
TYPES OF MICROTOME KNIVES
• Used to cut any type of resin block for electron microscopy
• Are brittle and expensive, but very durable
Diamond Knives
TYPES OF MICROTOME KNIVES
They are already mounted in a metal block designed to fit directly into the knife holder of the ultrathin microtome when purchased.
Microtome Knives
OTHER EQUIPMENT FOR TISSUE SECTIONING
• Temperature: About 10°C below the melting point of the paraffin wax.
• A small amount of detergent may be added to water to reduce surface tension and allow section to flatten out.
Floatation Water Bath
OTHER EQUIPMENT FOR TISSUE SECTIONING
Temperature is set at the melting point of the wax, to 2-5 degrees Celsius above*
Drying Oven or Hot Plate
OTHER EQUIPMENT FOR TISSUE SECTIONING
● To melt the paraffin
● Can be used to remove excess paraffin so that only the tissue is on the slide
Microwave
OTHER EQUIPMENT FOR TISSUE SECTIONING
Both are needed for handling sections during cutting and removing folds and creases during “floating out” in waterbath.
Forceps & Squirrel/Camel Hairbrush
Staining equipment should be?
Acid and alkali resistant, high temperature resistant
OTHER EQUIPMENT
Programmed to perform H&E routine staining without any supervision. This has a continuous load and unload drawer access and robotic arm system that routinely transfers stained slides to another reagent or stain.
Recommended in a busy histopathology laboratory
Automated Stainer/Autostainer
OTHER EQUIPMENT
These are covered glass vessels or containers, usually with grooves inside, and are used as containers of staining reagents during manual staining procedures.
Coplin Staining Jars
OTHER EQUIPMENT
These are covered glass vessels or containers, usually with grooves inside, and are used as containers of staining reagents during manual staining procedures.
Coplin Staining Jars
OTHER EQUIPMENT
Used to hasten the process of heating the slides after fishing the tissue section in the floatation water bath during sectioning in preparation for staining.
Up to 6 slide racks (30 slide capacities)
Slide Dryer
PARTS OF TISSUE EMBEDDING CENTER
It filters particles or sediments
Microscreen
PARTS OF TISSUE EMBEDDING CENTER
It forms a penthouse that contains molten paraffin. It has a microswitch dispenser usually on the lower left od the penthouse.
This chamber maintains an optimal paraffin temperature with adjustable thermostatic control
Paraffin Melting Chamber