HISTOPATHOLOGIC EXAMINATION Flashcards
Offers beneficial diagnostic information
HISTOPATHOLOGIC EXAMINATION
HISTOPATHOLOGIC EXAMINATION can be in what states
Fresh or Fixed state
Histopathologic examination
Factors affecting the method to be used:
USA
• urgency of investigation
• structures or inclusions
• amount and nature of the tissue
For rapid microscopic analysis while
surgery is taking place.
Fresh Tissue Examination
Fresh Tissue Examination Methods
FTCS
• FROZEN SECTIONS
• TEASING
• CRUSHING
• SMEAR PREP
Smear prep
PSST
• Pull-apart
• Streaking
• Spreading
• Touch Prep
Protoplasmic activities such as mitosis & phagocytosis may be observed when tissues are examined in its______
fresh state
diagnosis can be rendered in many cases,_____ tissue processing is preferred in many conditions for more accurate diagnosis.
fixed
The primary fixative reagent used to preserve tissue is
10% formalin
• Allows the examination of tissue in its living state.
FRESH TISSUE EXAMINATION
T or F
In fresh tissue examination
Slides may be viewed stained or unstained.
True
fresh (unfixed) tissue examination
advantages & disadvantages
Advantages:
Visualizing cell process such as motion, mitosis, phagocytosis, and pinocytosis.
Disadvantages:
Its use is limited because of the fact that tissues examined in the fresh state are not permanent, and therefore, are liable to develop the changes that have usually been observed after death.
________ are done by carefully separating very thin tissue slices with dissecting needles.
Slides are examined via _____ or _______microscopy where many details can be studied
Teased preparations
brightfield or phase contrast
are done by simply crushing small pieces of tissue between two glass slides or between a glass slide and a cover slip.
Squashed preparations
In examining sediments,_____ is usually the method of choice
smearing
Cellular materials are spread lightly over a slide with a wire loop or an applicator stick (such as in ____ or _____) or with another glass slide such as in the pull apart technique
streaking or in spreading
When rapid diagnosis is required, tissue sample is frozen and sectioned using the freezing microtome or cryostat. This procedure is called
Frozen Section
Technical name for frozen section
Cryosection
With the cryostat, the usual histology slice is cut at________
5 to 10 µm
In frozen section
The surgical specimen is placed on a metal tissue disc which is then secured in a chuck and frozen rapidly to about…
–20 to –30°C
In frozen section
The specimen is embedded in a _____medium consisting of _____ and _____; this compound is known by many names and when frozen has the same density as frozen tissue.
gel like
polyethylene glycol and polyvinyl alcohol
The preparation of the sample in frozen section is much more rapid than with traditional histology technique (around _____ vs____).
However, the technical quality of the sections is much lower.
10 mins
16 hrs
Procedure for Teasing and Dissociation:
- From the frozen block of tissue, cut several small, thin slices of tissue.
- Immerse the tissue slices in a petri dish filled with saline solution.
- Using a dissecting needle, carefully tease the tissue slices until they unfold and spread out.
- Carefully mount a teased slice on a slide and cover it with a coverslip
Procedure for Squash Preparation:
From the 4 th step of the previous procedure:
- Add 1-2 drops of methylene blue stain directly on the tissue slice on the glass slide.
- Cover the stained tissue with a cover slip or another glass slide.
- Applying enough pressure to crush the tissue flat.
- Label your slide with your name, group number and section and submit it to your instructor.
Procedure for Smear Preaparation:
Note:
Centrifuge body fluid samples and decant the supernatant. Save the sediments for the procedures below. Avoid making smears that are too thin or too thick since this will render your smears unsuitable for examination.
A. Streaking:
- Pour a small amount of the sediments on one end of a clean glass slide.
- Using an applicator stick, streak the sediments in a straight or zigzag line throughout the remaining length of the slide. If a wire loop is used instead, collect a loopful of the material and smear the material on the slide. A relatively uniform distribution of the material should be obtained. Cover it with a cover slip.
- Label your slide with your name, group number and section and submit it to your instructo
B. Spreading:
- Transfer a small amount of the sediments on one end of a clean glass slide.
- Using an applicator stick, spread the sediments throughout the slide (similar to how butter is spread on bread). Another technique is to place the drop of sediments at the center of the slide. Then with a circular motion, gently spread it into a moderately thick film.
- Label your slide with your name, group number and section and submit it to your instructor.
C. Pull apart
- Place a drop of the sediments at one end of a glass slide.
- Cover it with the end of another glass slide. Allow the sediments to spread evenly between the attached surfaces of the two slides.
- With a single, uninterrupted motion, pull the two slides apart in opposite directions. Cover the smear with a cover slip.
- Label your slide with your name, group number and section and submit it to your instructor
D. Touch or Impression smear
- Retrieve the block of tissue from the first procedure (See Teasing p.18).
Cut the block in half, exposing a fresher surface.
- Allow the freshly cut surface to come in contact with the surface of a clean glass slide. Apply gentle pressure, allowing the cells to be transferred directly to the slide. Cover the smear with a cover slip.
- Label your slide with your name, group number and section and submit it to your instructor
