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63 Cards in this Set
- Front
- Back
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When was the first frozen section recorded?
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in 1663
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When are frozen sections used?
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1. When a rapid diagnosis is needed.
2. When a staining technique will not work on a routinely processed tissue. |
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What is the theory behind frozen sections?
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processing involves replacing the water in tissue with a firm material such as paraffin. This involves an overnight process.
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What is a frozen section sometimes referred as?
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intraoperative consultation or a surgical consultation.
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Why would a surgeon need to know results right away?
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so that he could perform the correct surgery, like lumpectomy vs. mastectomy.
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What are frozen sections also used for?
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verifies the surgical margins are free of a tumor. Will also inform the surgeon with a preliminary diagnosis.
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What does CAP expect of the procedure?
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Expects there to be a 20 min. for total procedure.
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What does CAP also require?
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surgical consultations reports are made pat of the final surgical pathology report.
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What happen to the slides that have the frozen sections?
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they are permanently stained, mounted, properly labeled with the rest of the slides from the case.
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What happens to the rest of the tissue remaining from frozen section.
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It is routinely processed and a paraffin section prepared for comparison with the intraoperative consultation. There must be a correlation of FS with permanent tissue.
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What are some of the frozen sections necessary for?
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Enzyme histochemistry, immunofluorescent methods, immunohistochemical method, and staining methods for lipids.
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What happens to the enzymes when performing enzyme histochemistry?
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Many enzymes are inactivated by routine processing.
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What is required for demonstrating enzymes?
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Frozen sections are required.
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What kind of tissue is used for a immunofluorescent method?
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Fresh, unfixed frozen tissue.
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What are the cryostat sections cut at?
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2-5 microns
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what kind of tissue is common for immunofluorescent procedure?
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skin and kidney
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when doing a immunohistochemical, what is destroyed or altered?
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some antigens(epitopes) are formalin sensitive or destroyed or altered during routine processing. These tissues will need to frozen.
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Do lipids require to be demonstrated while being frozen?
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yes, they can not be done after routine processing unless fixed with osmium tetroxide.
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What are some of the stains used in demonstrating lipids?
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Oil red O or Sudan Black B stians.
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What is another staining procedure for frozen sections?
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Cajal method for astrocytes.
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when should you do frozen sections?
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Tissue should be frozen as soon as possible, to prevent, autolysis and putrefaction and to reduce diffusion of cellular components such as enzymes or antigens.
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what does the water in a frozen section?
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It provides firm support. the colder the temperature the firmer the tissue and visa versa.
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what is tissue support medium?
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it is a medium that is used to form external support around the tissue and glue the tissue to the chuck.
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how does paraffing differ from frozen support medium?
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frozen support medium infiltrates the cells of the tissue.
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What are the down falls of tissue support medium/
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1. It can slow down the freezing process
2. it can also prevent the tissue from drying out in extreme cold desiccation. |
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What are some tissue support mediums?
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OCT and Neg-50
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What is the support tissue made with?
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Water soluble glycols, vinyl alcohol polymers.
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What are frozen sections done on?
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Fixed or fresh tissue.
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when doing a frozen section, what is fixed tissue like?
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Fixed tissue has a will have a harder consistency due to the presence of of more water. warmer temperatures are required for fixed tissue.
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What fixatives should you avoid when doing a frozen section?
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Avoid mercury or chromate fixatives because they will make the tissue hard to section and are corrosive to the metal in the cryostat.
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what will alcohol fixatives do to frozen tissue?
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they will lower the freezing point of the tissue to a point where tissue will not freeze.
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what is the best temperature when doing a frozen section?
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It depends on what kind of tissue you are working with.
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what will happen is the tissue is too warm?
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the sections will be compressed.
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what happens if the tissue is too cold?
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the specimen will break and shatter.
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what was the freezing microtome replaced with?
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Cryostat
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what are cryostats?
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it is a rotary microtome withing a chamber kept at freezing temperatures. temperature can be adjusted.
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where are the controls for the cryostat?
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on the outside of the chamber.
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what are some of the new features of a cryostat?
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vacuum and disinfecting capabilities.
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what is one of the pieces mountedon the cryostat microtome that prevent the frozen sections from curling up?
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anti-role plate.
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what should you know about the anti-rolling plate?
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anti-rolling plate should be aligned parallel to the knife edge, free of any defects and clean, correct height to edge blade and the temperature of the cryostat chamber.
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blade should be what?
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should be 5-1.0 mm
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what happens if the anti roll plate is below the knife edge?
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The section will curl on the edge of the plate.
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What happens if the tissue is too far above the tissue?
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It will hit the anti-roll plate.
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What kind of blade do you use?
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the same as when you are doing a paraffin section. sharp. free of defects angle approximately 30 degrees and the same temperature as the cryostat.
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When sectioning the tissue, what is best?
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slow freezing of the tissue can produce freezing artifact (ice crystals throughout the tissue)
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What happens the longer the tissue takes to freeze?
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the longer it takes to freeze the larger the ice crystals.
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Tissue can be frozen using what other materials?
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isopentane, liquid nitrogen, liquid Freon, dry ice or a slurry of dry ice and acetone.
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blocks must be warmed to what?
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to the cryostat temperature before sectioning.
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How can chilling be done at the cryostat?
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it can be done with a cooling bar or heat extractors.
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How should the tissue be oriented?
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the same as you would with paraffin sectioning.
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what are some techniques you would use when embedding the tissue?
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OCT on chuck, tissue on OCT or
OCT on chuck, tissue on coverglass, sandwich together. |
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What are some of the techniques you could use when doing a frozen section.
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rapid freezing method
temperature optimal for tissue type ant-roll plate adjusted correctly |
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How do you pick up tissue to a slide?
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on room temperature slide, but fixed tissue may not adhere to the slide (use charged slides)
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How do you fix unfixed tissue?
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unfixed tissue can be fixed after it is picked up on slide.
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What are some ways to protect tissue from freezing damage?
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use a cryoprotectant such as dimethylsulphoxide (DMSO), glycerol, propylene glycol or sucrose (most common for fixed tissues.
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what helps to minimize ice crystals when doing frozen sections.
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Baby powder or talc can be sprinkled on the tissue to minimize ice crystals and to absorb excess moisture.
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what are some of the disadvantages when doing a frozen section?
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one section at a time, cannot get serial sections, distorted morphology, difficult to obtain thin sections, block storage difficult, and ice crystal damage.
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what are some of the advantages of frozen sections?
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Faster turn-around time.
preservation of antigens, enzymes life-like tissue, no processing artifacts |
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Why must cryostats be cleaned?
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to avoid biohazard health risks to the user and to avoid cross contamination of tissue, also avid using freezing sprays.
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How do pick up tissue shavings, when doing frozen sections?
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use alcohol dampened gauze and disposed of in a biohazard bag or vacuumed with a hepa filter.
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what should you use to wipe down the chamber of a cryostat?
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70% alcohol
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what should you do after defrosting the cryostat?
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the microtome must be thoroughly dried before turning it back on. Treatment with alcohol to dehydrate.
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How should the microtome be lubricated.
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It should be thoroughly lubricated with low temperature grease and oil. refrigeration unit kept dust free. preventative maintenance.
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