Term
| What stains carbohydrates and carbohydrate-rich macromolecules. It is used to demonstrate glycogen in cells, mucus in various tissues and cells, the basement membrane that that underlies epithelia, and reticular fibers in connective tissue? |
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Definition
| Periodic acid-Schiff (PAS) reaction (its color is magenta) vibrant purple |
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Term
| What relies on mild hydrochloric acid hydrolysis and is used to stain DNA? |
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Definition
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Term
| What facts are the PAS reactions based? |
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Definition
1) Hexose rings of carbohydrates contain adjacent carbons, each which bears a hydroxyl group (-OH).
2) Hexosamines of glycosaminoglycans contain adjacent carbons, one of which bears and -OH group, whereas the other bears and amino group (-NH2).
3) Periodic acid cleaves the bond between these adjacent carbon atoms and forms aldehyde groups.
4) These aldehyde groups react with the Schiff reagent to give a distinctive magenta color. |
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Term
| When is Feuglen used in clinical practice? |
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Definition
| It is used to study poly-ploidy and changes in DNA in cells undergoing differentiation. It is especially useful in studying adenocarcinomas (epithelial cancers) such as breast, kidney, colon, other gastrointestinal cancers, endometrial, and uterine cancer. |
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Term
| When is enzyme digestion used in staining? |
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Definition
| After staining particular reagents such as diatase or amylase will make sections of glycogen stained in a PAS rteaction disappear. DNAase will make DNA dissapear in a Feuglen reaction. Finally RNAase will get rid of RNA in the staining of ergastoplasm with basic dyes. |
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Term
| What method is used to identify and localize enzymes in cells and tissues? |
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Definition
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Term
| What are the four major steps in tissue preparation? |
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Definition
1) Fixation to preserve a sample
2) Specimen is embedded typically in paraffin.
3) The specimen is cut into sections and mounted.
4) The section is stained for examination. |
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Term
| Why do specimens go through fixation? |
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Definition
1) terminate cell metabolism
2) prevent enzymatic degradation of cells and tissues by autolysis (self-digestion)
3) kill pathogenic microorganisms (bacterira, fungi, viruses)
4) harden the tissue as a result of cross-linking or denaturing protein molecules |
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Term
| Why is Formalin used for fixation? |
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Definition
| It preserves the general structure of the cell and extracellular components by reacting with amino groups of proteins. It does not significantly alter the 3-D structure, also proteins can still react with antibodies. |
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Term
Tell me some of the differences about hematoxylin and eosin...
1) soluble in
2) dyes
3) charge
4) what type does it attract
5) color
6) acidity
7) when a charged substrate reacts with it, what is it called |
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Definition
hematoxylin eosin
1) water alcohol
2)DNA and cytoplasmic RNA proteins
3) positive negative
4) negative eq DNA positive eq proteins
5) blue red
6) not basic, but close to acidic
properties to it
7) basophilia acidophilia |
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Term
| What components of a cell remain typically after fixation? |
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Definition
1) nucleoproteins- nucleic acids bound to protein
2) intracellular cytoskeleton proteins- w/ associated proteins
3) extracellular proteins- in large soluble aggregates, bound or cross-linked to similar molecules as in colagen fibers
4) membrane phospholipid-protein (or carbohydrate) complexes |
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Term
| When are frozen sections used? |
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Definition
Usually during surgery, in order to determine how the surgery will procede. Its done when...
a- no preoperative diagnosis was available
b- unexpected operative findings must be identified
c- whether all of a pathological mass when in healthy tissue is removed
d- in combination with other procedures such as endoscopy or thin needle biopsy |
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Term
| What are the three steps in a Frozen Section and how long does the process take? |
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Definition
1)Freeze the tissue sample
2) Section the frozen tissue
3) stain the cut sections
It can take as little as 10 mins |
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Term
| makes use of a photographic emulsion placed over a tissue section to localize radioactive material within tissues |
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Definition
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Term
| method of localizing messenger RNA (mRNA) or DNA by hybridizing the sequence of interest to a complementary strand of a nucleotide probe |
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Definition
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Term
| the process of enlarging something only in appearance |
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Definition
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Term
| quantifies how close lines can be to each other and still be visibly resolved |
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Definition
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Term
| Certain basic dyes react with tissue components that shift their normal color from blue to red or purple; this absorbance change is called? |
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Definition
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