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413 Cards in this Set
- Front
- Back
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An example of an additive fixation is one that contains:
a) mercuric chloride b) acetic acid c) ethyl alcohol d) acetone |
a) mercuric chloride
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When compared with tissue fixed in formalin, tissue fixed in zinc-formalin will show:
a) better ultrastructural preservation b) decreased immunoreactivity c) increased enzyme activity d) superior nuclear detail |
d) superior nuclear detail
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Micoscopic examination of an H&E-stained section fixed in formalin shows marked nuclear bubbling. One most often sees this artifact if the specimen is processed following:
a) underfixation b) prolonged fixation c) microwave fixation d) frozen sectioning |
a) underfixation
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Microscopic evaluation of H&E-stained sections from a surgically removed small bowel specimen show an absence of much of the epithelium in otherwise normal tissue. This most likely resulted from:
a) mechanical trauma b) delayed fixation c) ulceration d) poor choice of fixative |
b) delayed fixation
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A specimen of kidney must be shipped to another city for immunofluorescence studies. The specimen should be placed in:
a) saline b) Michel solution c) buffered formalin d) Orth solution |
b) Michel solution
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In a certain project it is important to use a fixative that contains acetic acid yet stabilizes erythrocyte membranes. One fixative that could be used is:
a) Zenker solution b) Bouin solution c) Gendre solution d) Hollande solution |
d) Hollande solution
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When a microwave oven is used for fixation, the most critical factor is the:
a) preparation of the formalin solution b) use of glass containers c) control of the temperature d) osmolality of the fixation solution |
c) control of the temperature
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To adequately remove the calcium in a specimen containing areas of microcalcifications, the tisse could be fixed in:
a) Hollande solution b) NBF c) B-5 solution d) Zamboni solution |
a) Hollande solution
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Which of the following fixatives contains copper acetate?
a) Hollande b) Bouin c) Gendre d) Zamboni |
a) Hollande
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A specimen is submitted with the statement that it was fixed if formalin. Microscopic sections show marked lysis of erythrocytes. This indicates that the fixative most likely was:
a) prepared with too much formalin b) buffered above neutrality c) acetified with acetic acid d) not formalin |
c) acetified with acetic acid
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Fixatives are classified as additive because of the:
a) addition of several chemicals to the solution b) addition, or binding of the fixative, to tissue proteins c) additional reactions occurring with longer fixation d) additional reactive tissue sites available for dye binding |
b) addition, or binding of the fixative, to tissue proteins
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The only kidney biopsy tissue available has been fixed in phosphate-buffered glutaraldehyde for 2 hours and then placed in phosphate buffer solution. If a portion of this tissue is processed for light microscopy, sections would most likely show:
a) very poor glomerular preservation b) decreased uptake of hematoxylin c) lysis of cytoplasmic elements d) nonspecific PAS staining |
d) nonspecific PAS staining
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Uric acid crystals are preserved only when tissue is fixed in:
a) absolute alcohol b) NBF c) Orth solution d) Zamboni solution |
a) absolute alcohol
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Improper preservation of issue will result if there is:
a) a delay in fixation b) rapid penetration of the fixing fluid c) prolonged storage following formalin fixation d) rapid dehydration, clearing, embedding, and sectioning |
a) a delay in fixation
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A good fixative will:
a) render cell constituents soluble b) minimize differences in tissue refractive indices c) protect tissue against alteration by subsequent processing d) minimally affect tissue metabolic processes |
c) protect tissue against alteration by subsequent processing
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The function of methanol in commercial formalin solutions is to:
a) retard the polymerization of formaldehyde b) prevent the formation of formic acid c) stabilize the formalin at a basic pH d) permit the storage of formalin at room temperature |
a) retard the polymerization of formaldehyde
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The subsequent demonstration of chromaffin granules requires which of the following fixatives?
a) Orth b) Bouin c) B-5 d) formalin |
a) Orth
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In electron microscopy, Zamboni fluid, glutaraldehyde, and osmium tetroxide function as:
a) dehydrating agents b) clearing agents c) embedding media d) fixatives |
d) fixatives
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Tissue will remain unfixed if placed in:
a) potassium dichromate b) sodium borate c) osmium tetroxide d) zinc chloride |
b) sodium borate
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Bouin solution is contraindicated for:
a) small tissue biopsies b) tissue intended for subsequent trichrome stains c) tissue to be stained by the Feulgen reaction d) routine tissue sections |
c) tissue to be stained by the Feulgen reaction
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Formalin pigment can be removed from tissue sections by treatment with 10%:
a) hydrochloric acid in 70% alcohol b) nitric acid in 70% alcohol c) sulfuric acid in 70% alcohol d) ammonium hydroxide in 70% alcohol |
d) ammonium hydroxide in 70% alcohol
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Stock neutralized formalin is prepared in the laboratory by storing the solution over a layer of calcium carbonate.The solution withdrawn from this stock container will:
a) become acidic b) become alkaline c) remain neutral d) exhibit metachromasia |
a) become acidic
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Microscopic evaluation reveals a very poorly-stained H&E section of spleen. These results will be difficult to remedy if the problem is:
a) poor fixation b) improper sectioning c) poor staining d) incorrect section placement |
a) poor fixation
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To make a 10% formalin solution, how many mL of water should be added to 300mL of 37% to 40% formaldehyde solution?
a) 1800 b) 2500 c) 2700 d) 3600 |
c) 2700
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One action of acetic acid is to:
a) exert a shrinking effect on tissue b) render nucleoprotein acidophilic c) form salt linkages between protein chains d) coagulate nucleoproteins |
d) coagulate nucleoproteins
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Aldehyde fixatives are used for electron microscopy preparation because they:
a) are readily available b) visibly stain tissue c) preserve cell ultrastructure d) coagulate tissue lipids |
c) preserve cell ultrastructure
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A fixative containing potassium dichromate:
a) is suitable when histochemical techniques are planned b) will result in excellent subsequent silver staining c) is preferred for the preservation of argentaffin cells d) will make tissue more receptive to eosin staining |
d) will make tissue more receptive to eosin staining
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If mercuric chloride is used alone for fixation, it will:
a) leave tissue proteins uncoagulated b) produce a very acidic solution c) penetrate poorly and cause excessive shrinkage d) decrease tissue affinity for stains |
c) penetrate poorly and cause excessive shrinkage
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Tissue stored for long periods of time in unbuffered formalin or in acetate-buffered formalin may show brown, crystalline pigment in stained sections. To remove this pigment prior to staining it is necessary to treat the section in:
a) saturated alcoholic picric acid b) alcoholic lithium chloride c) iodine and sodium thiosulfate d) potassium permanganate and oxalic acid |
a) saturated alcoholic picric acid
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For good fixation of specimens for electron microscopy, it is recommended that the tissue segment be no larger than:
a) 1mm b) 2mm c) 1cm d) 2cm |
a) 1mm
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Waxes that are commonly used in the preparation of tissue sections for light microscopic evaluation are NOT used in electron microscopy because tissues prepared in wax:
a) cannot be stained with osmium tetroxide b) are too hard for thin sectioning c) are not transparent d) will not withstand an electron beam |
d) will not withstand an electron beam
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Following fixation with Bouin solution, tissue should be washed with:
a) absolute alcohol b) 50% to 70% alcohol c) 20% to 40% alcohol d) saline solution |
b) 50%-70% alcohol
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Zenker fluid is the recommended fixative for subsequent:
a) PTAH staining b) frozen staining c) hemosiderin preservation d) erythrocyte demonstration |
a) PTAH staining
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The acetic acid present in some fixatives:
a) coagulates and shrinks cytoplasmic proteins b) dissolves some cytoplasmic organelles and deposits c) penetrates tissue very slowly and incompletely d) hardens the tissue markedly |
b) dissolves some cytoplasmic organelles and deposits
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Absolute ethanol is a poor choice for the fixation of:
a) glycogen b) pigments c) lipids d) blood smears |
c) lipids
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Which of the following fixatives may give false-positive results in carbohydrate demonstration?
a) NBF b) Bouin solution c) Gendre solution d) glutaraldehyde |
d) glutaraldehyde
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It is necessary to adjust the pH of most formalin solutions because of the presence of:
a) methanol b) formic acid c) paraformaldehyde d) carbon dioxide |
b) formic acid
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The rate of fixation varies with the fixative and is also dependent upon:
a) grossing pathologist's preference b) expected completion time of the report c) anticipated special stains d) temperature of the fixative |
d) temperature of fixative
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Carnoy solution is recommended for the preservation of:
a) acid-fast bacilli b) nucleic acids c) lipids d) red blood cells |
b) nucleic acids
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Orth solution contains all of the following except:
a) potassium dichromate b) mercuric chloride c) sodium sulfate d) 37% to 40% formaldehyde |
b) mercuric chloride
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Formalin pigment is generally created in tissues fixed in formalin when the pH:
a) rises above 6 b) falls below 6 c) is buffered to neutrality d) is 7.2 |
b) falls below 6
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A universal fixative used for routine purposes thatallows a broad spectrum of staining procedures is:
a) Zenker fluid b) Zamboni PAF c) 10% NBF d) Carnoy solution |
c) 10% NBF
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One advantage of fixing tissue in Zenker solution is that:
a) the prolonged treatment keeps the tissue soft and pliable b) Zenker-fixed tissues stain brilliantly c) artifactual pigments are not formed d) washing after fixation is not required |
b) Zenker-fixed tissues stain brilliantly
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A tissue section was not initially placed in the fixative required for a staining procedure. However, after deparaffinization and rehydration, sections frequently can be stainied anyway if they are:
a) soaked in solution of lithium carbonate prior to staining b) revitalized by washing in a solution of sodium bisulfate c) post-fixed in the appropriate fixative prior to stianing d) treated with hydrogen peroxide |
c) post-fixed in the appropriate fixative prior to staining
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Helly fluid contains all of the following EXCEPT:
a) mercuric chloride b) potassium dichromate c) sodium sulfate d) glacial acetic acid |
d) glacial acetic acid
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Fixation in Bouin solution is:
a) recommended for the Feulgen reaction b) excellent for ultrastructural preservation c) the cause of considerable swelling of tissue d) frequently used for endocrine tissues |
d) frequently used for endocrine tissues
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B-5 fixative contains:
a) mercuric chloride, sodium acetate, and glacial acetic acid b) mercuric chloride, potassium dichromate, and glacial acetic acid c) mercuric chloride, sodium acetate, and 37% to 40% formaldehyde d) mercuric chloride, potassium dichromate, and 37% to 40% formaldehyde |
c) mercuric chloride, sodium acetate, and 37% to 40% formaldehyde
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Pigment caused by mercury-containing fixatives can be removed from tissues by:
a) saturated alcoholic picric acid b) iodine-sodium thiosulfate c) washing in running water d) potassium hydroxide in water |
b) iodine-sodium thiosulfate
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Which of the following fixatives has a mordanting effect on tissue?
a) Carnoy solution b) 10% calcium formalin c) absolute alcohol d) Zenker solution |
d) Zenker solution
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Tissue should be placed in a suitable fixative immediately after removal from the body to:
a) prevent decomposition due to enzymatic activity b) permit the dehydrant to function properly c) inhibit cross-linking of tissue proteins d) stabilize tissue carbohydrates |
a) prevent decomposition due to enzymatic activity
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Baker calcium-formalin fixative is recommended for the best preservation and subsequent demonstration of:
a) glycogen b) phospholipids c) amyloid d) estrogen receptors |
b) phospholipids
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For most fixatives, the volume of fixing fluid in relation to the volume of tissue should be:
a) 2 to 5 times b) 6 to 9 times c) 10 to 14 times d) 15 to 20 times |
d) 15 to 20 times
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Ultrastructural preservation will be very poor following fixation in:
a) Zamboni PAF b) 2% buffered glutaraldehyde c) osmium tetroxide d) 10% aqueous formalin |
d) 10% aqueous formalin
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The fixation of tissue begins at the:
a) center and proceeds outward b) center and proceeds inward c) periphery and proceeds outward d) periphery and proceeds inward |
d) periphery and proceeds inward
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Zinc-formalin fixatives:
a) give poor ultrastructural preservation b) can be used to preserve enzymes c) result in poor nuclear detail d) will not coagulate tissue proteins |
a) give poor ultrastructural preservation
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Zamboni PAF refers to a fixative containing:
a) potassium dichromate, acetic acid, and formaldehyde b) potassium aluminum sulfate and paraformaldehyde c) buffered picric acid and formaldehyde d) picric acid, acetic acid, formaldehyde |
c) buffered picric acid and formaldehyde
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Excess fixative must be removed from specimens before placing them in dehydrating solutions if the fixative contains:
a) glutaraldehyde b) mercuric chloride c) picric acid d) potassium dichromate |
d) potassium dichromate
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The preferred fixative when tissue is to be stained for the prescence of simple fats is:
a) Zenker b) Helly c) Hollande d) NBF |
d) NBF
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Which of the following is recommended for central nervous system tissues to be stained with the Cajal technique?
a) neutralized formalin b) formalin ammonium bromide c) paraformaldehyde d) alcoholic formalin |
b) formalin ammonium bromide
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When osmium tetroxide is used as a fixative in histology, it:
a) destroys lipids b) interferes with staining c) leaves tissue very soft d) distorts cell membranes |
b) interferes with staining
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The breakdown of tissue due to enzyme activity is called:
a) polymerization b) putrefaction c) autolysis d) osmosis |
b) autolysis
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The fixative of choice for the demonstration of urate crystals is:
a) NBF b) absolute alcohol c) Bouin solution d) Zenker solution |
b) absolute alcohol
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A good fixative for routine use is one that:
a) makes tissue more permeable to fluids b) is hypotonic to the tissue constituents c) enhances putrefaction of tissue components d) promotes tissue autolysis |
a) makes tissue more permeable to fluids
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A pigment caused by chromate-containing fixatives can be prevented by treating the tissue prior to processing with:
a) running water b) iodine c) picric acid d) potassium permanganate |
a) running water
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When fixing tissue with formaldehyde or glutaraldehyde, proper enzyme activity and preservation of structure depend upon all of the following EXCEPT:
a) pH b) time and temperature c) concentration and purity of the reagent d) type of tissue |
d) type of tissue
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Formic acid present in commercial formalin solutions may:
a) facilitate pigment formation b) precipitate hemosiderin c) promote staining d) cause tissue shrinkage |
a) facilitate pigment formation
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Carnoy solution is a combination of which of the following chemicals?
a) absolute alcohol, acetone, and glacial acetic acid b) cedarwood oil, absolute alcohol, and glacial acetic acid c) acetone, chloroform, and absolute alcohol d) chloroform, glacial acetic acid, and absolute alcohol |
d) chloroform, glacial acetic acid, and absolute alcohol
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When staining chromaffin cells for the diagnosis of pheochromocytoma, it is necessary to fix the tissue in a:
a) mercury fixative b) primary chromate fixative c) formalin fixative d) picric acid fixative |
b) primary chromate fixative
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When liver tissue is fixed with 2% to 3% glutaraldehyde:
a) protein is only partially perserved b) the penetration rate is very rapid c) a chemical reaction occurs with lipids d) the ultrastructure is preserved |
d) the ultrastructure is preserved
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A poor fixative is characterized by:
a) the absence of shrinking or swelling of tissue b) inactivation of tissue enzymes c) slow tissue penetration d) the absence of distortion or dissolution |
c) slow tissue penetration
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Which of the following fixatives requires washing with water before processing?
a) Carnoy b) Bouin c) 10% formalin d) Zenker |
d) Zenker
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Bouin solution contains all of the following EXCEPT:
a) picric acid b) absolute alcohol c) 37% to 40% formaldehyde d) glacial acetic acid |
b) absolute alcohol
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Coagulant fixatives:
a) change the spongework of proteins into meshes b) produce fewer artifacts than noncoagulant fixatives c) act very slowly to fix tissues d) leave protein linkages unaffected |
a) change the spongework of proteins into meshes
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The breakdown of tissue by bacterial action is called:
a) autolysis b) putrefaction c) denaturation d) oxidation |
b) putrefaction
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When ultrastructural preservation is of the utmost importance, the fixative used should have a pH of:
a) 6.8 to 7.0 b) 7.2 to 7.4 c) 7.6 to 7.8 d) 8.0 to 8.2 |
b) 7.2 to 7.4
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A fixative that produces a diffuse brownish black pigment is:
a) Bouin b) Carnoy c) Zenker d) alcohol |
c) Zenker
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For the BEST preservation of staining properties during long-term storage, tissues should be stored in:
a) buffered formalin b) 10% formal-saline c) 70% ethanol d) Zamboni solution |
c) 70% ethanol
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Ethanol is useful as a fixative because it:
a) rapidly dehydrates tissue b) increases tissue basophilia c) stabilizes red cell membranes d) preserves glycogen very well |
d) preserves glycogen very well
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Mercuric chloride pigment may be removed from tissue by:
a) treating sections with an iodine-sodium thiosulfate sequence b) using limonene clearing agent on the tissue processor c) rinsing sections with 50% to 70% alcohol d) washing sections with running water |
a) treating sections with an iodine-sodium thiosulfate sequence
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To prevent the formation of formalin pigment in tissues, formalin should be:
a) heated b) cooled c) buffered d) acidified |
c) buffered
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Which of the following fixatives should be used for specimens that are to be mailed?
a) 10% NBF b) Bouin solution c) Helly solution d) Zenker solution |
a) 10% NBF
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A biopsy that was placed in water by mistake is submitted to the laboratory. This mistake most likely will cause:
a) mushy sections b) swollen or ruptured cells c) hardening of the tissue d) no appreciable changes |
b) swollen or ruptured cells
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Sections of a breast carcinoma were fixed in a saline solution in the microwave oven. Microscopic examination of the H&E-stained sections show marked pyknotic, overstained nuclei. The staining results were most likely caused by the:
a) use of saline for fixation b) solution temperature exceeding 55⁰C c) use of plastic containers in the microwave d) presence of carcinoma in the breast tissue |
b) solution temperature exceeding 55⁰C
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An unknown pigment in a tissue section that can be bleached with a saturated alcoholic solution of picric acid is most likely:
a) melanin pigment b) formalin pigment c) hemosiderin d) mercury pigment |
b) formalin pigment
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The formaldehyde in Helly solution:
a) causes reduction of some chemicals in the solution b) coagulates and denatures tissue proteins c) prevents turbidity and precipitate formation d) eliminates the need for post-fixation washing |
a) causes reduction of some chemicals in the solution
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Formaldehyde solutions for routine use are most commonly buffered by:
a) monobasic and dibasic phosphates b) sodium acetate and acetic acid c) s-collidine and hydrochloric acid d) sodium barbitol and sodium hydroxide |
a) monobasic and dibasic phosphates
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If asked to cut cryostat sections of tissue fixed in Zenker solution, the histotechnologist should:
a) section the tissue as is b) explain that frozen sections containing mercuric chloride cannot be made c) treat the tissue with iodine, hypo, and water before freezing d) use a solution of 30% sucrose to infiltrate the tissue before freezing |
c) treat the tissue with iodine, hypo, and water before freezing
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One characteristic of Zamboni fixative is that it:
a) does not stabilize cellular proteins b) is recommended for electron microscopy c) is easily destroyed by tissue fluids d) must be followed by osmium tetroxide |
b) is recommended for electron microscopy
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The best fixative for blood smears is:
a) Bouin solution b) Carnoy solution c) B-5 solution d) methanol |
d) methanol
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When used as a secondary fixative, osmium tetroxide should be:
a) used after lead citrate b) heated prior to use c) combined with alcohol d) used under a chemical hood |
d) used under a chemical hood
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Which of the following fixatives is recommended for use in lipid histochemistry?
a) Zenker solution b) acetone c) formalin-saline d) calcium-formalin |
d) calcium-formalin
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In the Cajal method for demonstrating astrocytes, sections of brain should be fixed in formalin that contains:
a) sodium acetate b) ammonium bromide c) mercuric chloride d) calcium chloride |
b) ammonium bromide
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Hollande solution is a modification of which of the following fixatives?
a) Helly solution b) Orth solution c) Carnoy solution d) Bouin solution |
d) Bouin solution
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Tissue fixed in which of the
following solutions must be post-treated for mercuric chloride pigment? a) B-5 b) Zamboni c) Carnoy d) Orth |
a) B-5
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Acetone is recommended for the primary fixation of:
a) prostate tissue for immunohistochemistry b) kidney tissue for fluorescent antibody techniques c) muscle tissue for enzyme histochemistry d) brain tissue for the diagnosis of rabies |
d) brain tissue for the diagnosis of rabies
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Fresh unfixed tissue can be stored safely for a short time by:
a) keeping it in a freezer b) wrapping it in saline-moistened gauze and refrigerating it c) placing it in physiological saline at room temperature d) leaving it in a dry specimen container on the counter with a note to the histologist |
b) wrapping it in saline-moistened gauze and refrigerating it
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Zenker solution contains:
a) mercuric chloride, potassium dichromate, and formaldehyde b) mercuric chloride, chromic acid, and formaldehyde c) mercuric chloride, potassiume dichromate and acetic acid d) potassium dichromate, formaldehyde, and acetic acid |
c) mercuric chloride, potassium dichromate, and acetic acid
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One characteristic of Bouin solution is that it:
a) penetrates poorly b) destroys delicate structures c) mordants connective tissue stains d) preserves erythrocyes |
c) mordants connective tissue stains
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The fixation of tissue by physical methods can be demonstrated by the use of:
a) microincineration b) microwaves c) frozen sections d) alcohol |
b) microwaves
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Fixation in Carnoy solution will result in:
a) swelling of the tissue b) preservation of most cytoplasmic structures c) superior staining of amyloid and Congo red d) good preservation of red blood cells |
c) superior staining of amyloid and Congo red
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The recommended fixative for tissue suspected of containing spirochetes is:
a) 10% NBF b) Bouin solution c) Zenker solution d) Helly solution |
a) 10% NBF
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Which of the following is frequently added to formalin solutions to help preserve immunoreactivity?
a) glycerin b) sodium acetate c) zinc salts d) chromates |
c) zinc salts
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Which of the following fixatives is recommended for both the Heidenhain and Mallory aniline blue stains?
a) Orth fluid b) NBF c) Zenker fluid d) absolute alcohol |
c) Zenker fluid
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A fixative used for the preservation of some enzymes is:
a) Bouin solution b) B-5 solution c) acetone d) isopropanol |
c) acetone
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A common reason for adding acetic acid to fixatives is it:
a) coagulate proteins b) reduce shrinkage c) preserve carbohydrates d) change the pH |
b) reduce shrinkage
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Formaldehyde acts as a fixative by:
a) uncovering acid groups b) coagulating proteins c) cross-linking proteins d) rupturing peptide linkages |
c) cross-linking proteins
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When it is known prior to fixation that a distinction must be made between collagen and muscle, the preferred fixative is:
a) NBF b) Orth fluid c) absolute alcohol d) Bouin fluid |
d) Bouin fluid
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For optimum staining results, Bouin or Zenker fixation is recommended for:
a) the Wilder reticulum techniques b) most trichrome stains c) the Weigert elastic tissue stain d) any silver stain |
b) most trichrome stains
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In Bouin fixative, the shrinking effect produced by one component is balanced by the swelling effect of:
a) formalin b) acetic acid c) osmium tetroxide d) potassium dichromate |
b) acetic acid
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10% formalin is equivalent to what percentage of paraformaldehyde?
a) 40 b) 10 c) 4 d) 1 |
c) 4
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The use of formalin as a fixative in the mircowave oven:
a) is a possible explosive hazard b) produces toxic vapors c) degrades plastic cassettes d) corrodes fixed tissues |
b) produces toxic vapors
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Which of the following renders fat insoluable for subsequent processing?
a) picric acid b) osmium tetroxide c) chloroform d) formldehyde |
b) osmium tetroxide
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The presence of acetic acid in fixatives produces:
a) cell shrinkage b) red cell destruction c) protein coagulation d) lipid preservation |
b) red cell destruction
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Microscopic review of a formalin-fixed tissue section demonstrates a fine, brown-black artifactual pigment. This artifact most likely could have been prevented by:
a) placing the tissue in formalin immediately after removal b) preparing the solution just before use c) washing the tissue after fixation d) making the solution neutral |
d) making the solution neutral
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When osmium tetroxide is used as a fixative, it:
a) must be used after a primary fixative b) should be used in a hood c) should be more hypotonic to tissue d) must be made basic |
b) should be used in a hood
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Which of the following fixative components produces shrinkage and penetrates poorly:
a) glacial acetic acid b) mercuric chloride c) potassium dichromate d) ethanol |
b) mercuric chloride
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The component in Bouin solution that causes tissue shrinkage is:
a) picric acid b) acetic acid c) mercuric chloride d) potassium dichromate |
c) mercuric chloride
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Which of the following fixatives should be selected when it is desirable to preserve erythrocytes in tissue?
a) Zenker b) Bouin c) Carnoy d) B-5 |
d) B-5
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A tissue section reveals a dark brown microcrystalline pigment that is birefringent. To remove the pigment, the section should be treated with an alcoholic solution saturated with:
a) sodium thiosulfate b) oxalic acid c) picric acid d) hydrochloric acid |
c) picric acid
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Shrinkage and distortion of tissue is greatest following fixation in:
a) Zenker fluid b) Bouin solution c) absolute alcohol d) Helly fluid |
c) absolute alcohol
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Tissue to be stained by the Warthin-Starry technique should be fixed in:
a) Zenker fluid b) saturated mercuric chloride c) formalin d) osmium tetroxide |
c) formalin
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Alcohol, rather than water, is used as the solvent in some fixatives because alcohol:
a) helps precipitate proteins b) decreases tissue shrinkage c) increases lipid preservation d) eliminates the need for dehydration |
a) helps precipitate proteins
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When preparing Helly solution, formalin should be added:
a) when other ingredients are combined b) before adding mercuric chloride c) when ready to use d) 24 hours before use |
c) when ready to use
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When fat is to be preserved, the fixative of choice is:
a) formalin b) Zenker solution c) Carnoy solution d) Bouin solution |
a) formalin
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Picric acid was used alone as a fixative for a section of liver. The tissue most likely will show:
a) extreme swelling b) excessive hardening c) an increased uptake of eosin d) hydrolyzed nucleic acids |
d) hydrolyzed nucleic acids
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The primary purpose of fixation is the:
a) preservation of carbohydrates b) coagulation of lipids c) removal of tissue fluids d) stabilization of proteins |
d) stabilization of proteins
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Bouin solution lyses erythrocytes because it contains:
a) formalin b) picric acid c) acetic acid d) alcohol |
c) acetic acid
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What is the purpose of fixation?
|
fixatives alter tissue making it resistant to further changes by stabilizing proteins or making the soluble contents insoluble
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|
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define: autolysis
|
destruction or digestion of tissues and cells by the enzymes normally present in th cells
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fixation
|
stabilization of proteins
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define: artifact
|
a structure or substance not normally present but produced by some external force or action
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examples of artifacts
|
mercury pigment, tissue floaters, knife lines, and air bubbles
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pigment
|
heterogeneous group of substances that contain enough natural color to be visible without any further staining
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examples of pigments
|
melanin, ferric iron, bile, calcium, hematin
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nonaqueous fixatives
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fixatives that do not contain water
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examples of nonaqueous fixatives
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acetone and alcohol
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define: coagulating fixative
|
establish a network in tissue that allows solutions to readily penetrate or gain entry into the interior of the tissue
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define: additive fixatives
|
chemically link to the tissue and change it
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define: hypertonic solution
|
a solution that will cause a cell to shrink
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define: hypotonic solution
|
a solution that will cause a cell to swell
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define: isotonic
|
a solution that will cause the cell to neither shrink or swell
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examples of isotonic solutions for animal tissue
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.9% saline solution or 5% glucose solution
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acetic acid fixes...
|
nucleoproteins
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acetone fixes...
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enzymes
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ethanol fixes...
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glycogen and urate crystals
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methanol fixes...
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blood smears
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B-5 fixative fixes...
|
hematopoietic and lymphoreticular tissue
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bouin solution fixes...
|
-tissue to be trichrome stained
-GI specimen -embryonic studies -skin |
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carnoy and methacarn solutions fix...
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glycogen
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formalin fixes...
|
most tissues
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Gendre solution fixes...
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glycogen
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gluteraldehyde fixes...
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tissue for electron microscopy
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glyoxal fixes...
|
most tissue (similar to formalin)
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Helly solution fixes...
|
tissue needing good nuclear detail
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Hollande solution fixes...
|
small bone and GI specimen
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mercuric chloride fixes...
|
most tissues (similar to formalin)
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Orth solution fixes...
|
nucleus
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osmium tetroxide fixes...
|
-lipids
-tissue needed for electron microscopy |
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paraformaldehyde fixes...
|
most tissues (similar to formalin)
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potassium dichromate fixes...
|
mitochondria
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Zamboni solution fixes...
|
nucleus
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Zenker solution fixes...
|
nucleus
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zinc formalin fixes...
|
immunohistochemical studies
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tissue is fixed in order to...
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stop enzymatic action
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Which fixative contains picric acid, formalin and acetic acid?
|
Bouin solution
|
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The volume of fixative should exceed the volume of the tissue by...
|
10 to 20 times
|
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Tissue must be washed in running water after fixation with...
|
Zenker solution
|
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Which fixative contains formalin, potassium dichromate, and mercuric chloride?
|
Helly
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Precipitate left in tissues that have been fixed in solutions containing mercuric chloride may be removed by immersion in...
|
iodine
|
|
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Commercial stock formaldehyde solutions contain what percentage of formaldehyde?
|
37%-40%
|
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Formalin pigment is most likely to form in tissues if the pH of the formalin solution is at or below...
|
5.0
|
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Formalin pigment may be removed from tissue by...
|
alcoholic picric acid
|
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10% formalin is the same as what percentage of formaldehyde?
|
4%
|
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For best results when using formalin as a routine fixative, it must be made...
|
neutral
|
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Absolute alcohol is indicated as a primary fixative if the tissue is to be processed for the demonstration of...
|
urate crystals
|
|
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Autolysis of tissue is caused by...
|
enzymatic activitiy
|
|
|
To prepare a 10% solution of formalin, how much water should be added to 100mL of stock formaldehyde?
|
900mL
|
|
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The ratio of stock solution to acid in Zenker fixative is...
|
20 parts stock to 1 part acetic acid
|
|
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What tissue change will occur if acetic acid is used alone as a fixative?
|
swelling
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A good fixative for central nervous system tissue to be stained with silver or gold techniques is...
|
formalin ammonium bromide
|
|
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After fixing tissue in Bouin solution, the excess picric acid is frequently removed by washing in...
|
50% to 70% alcohol
|
|
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Carnoy fluid is prepared with acetic acid, alcohol, and...
|
chloroform
|
|
|
The first and most important procedure in the preparation of a tissue for microscopic examination is the choice of...
|
fixative
|
|
|
Fats are usually preserved best if the tissue is fixed in...
|
osmium tetroxide
|
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When alcohol is used as the primary fixative, one should expect...
|
excessive tissue shrinkage
|
|
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Generally, an increase in the temperature of the fixative solution...
|
increases the speed of fixation
|
|
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What is a cause of tissue overhardening?
|
prolonged fixation
|
|
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Fixatives containing chromate salts usually require...
|
washing in water
|
|
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Substitution of alcohol as the diluting solution for formaldehyde results in...
|
better preservation of glycogen
|
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Zinc salts are added to some formalin fixatives to...
|
provide superior nuclear detail
|
|
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Tissue fixed in glutaraldehyde is not satisfactory for...why?
|
the PAS reaction, the extra aldehyde chain reacts with the schiff's to give a false positive result
|
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For immunofluorescence, the tissue sould be fixed in...
|
nothing, tissue should be unfixed
|
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What is an example of a nonaqueous combined fixative?
|
Carnoy
|
|
|
What fixatives will leave the tissue protein uncoagulated?
|
osmium tetroxide
|
|
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To prevent polymerization of formaldehyde, what is added to the commercial stock solutions?
|
methyl alcohol
|
|
|
polymerized formaldehyde is known as...
|
paraformaldehyde
|
|
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Formaldehyde reacts with protein side chains by combining with the...
|
amino group
|
|
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Formaldehyde cross-links proteins by reacting with which group?
|
NH2 (amino group)
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What is an example of a nonadditive fixative?
|
ethyl alcohol
|
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Potassium dichromate increases availability of what group for binding dyes?
|
amino group
|
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Which types of pigments are preventable?
|
formalin and chromium
|
|
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Which types of pigments are removable?
|
formalin and mercury (chromium is partially removed)
|
|
|
How is formalin pigment removed?
|
saturated alcoholic picric acid, alkaline alcohol
|
|
|
How is mercury pigment removed?
|
iodine followed by sodium thiosulfate
|
|
|
Can chromium pigment be removed? If so how?
|
-partially
-acid alcohol |
|
|
T/F: Formalin fixation stabilizes lipids
|
-False
-osmium tetroxide does |
|
|
T/F: Acetic acid is an excellent nuclear fixative
|
-True
|
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T/F: Fat is well preserved by Carnoy solution
|
-False
-Osmium Tetroxide |
|
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T/F: Formalin penetrates rapidly but fixes slowly
|
-True
|
|
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T/F: 10% formalin is a 1:4 dilution of commercial formalin
|
-False
-1:9 dilution |
|
|
T/F: Zenker fixative contains formalin, mercuric chloride, and potassium dichromate
|
-False
-mercuric chloride, potassium dichromate, sodium sulfate, acetic acid |
|
|
T/F: Fixation in Helly solution will preserve erythrocytes, while fixation in Zenker solution will not
|
-true
|
|
|
T/F: Bouin solution contains picric acid, formalin and hydrochloric acid
|
-false
-picric acid, formalin and acetic acid |
|
|
T/F: Any fixative containing mercuric salts will leave a deposit of crystals in the tissue
|
-true
|
|
|
T/F: Mercury crystals may be removed from tissue by immersion in sodium thiosulfate
|
-false
-immersed in iodine and rinsed with sodium thiosulfate |
|
|
T/F: Formalin ammonium bromide is a very good fixative for connective tissue
|
-false
-nerve tissue |
|
|
T/F: The fixing fluid considered best for the preservation of nuclear detail is formalin
|
-false
|
|
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T/F: Formalin pigment can be removed from tissue by immersion in alcoholic picric acid
|
-true
|
|
|
T/F: The volume of the fixative should exced the volume of the tissue by 1 to 2 times
|
-false
-10-20 times |
|
|
T/F:Tissue left in fixative beyond the defined time may become excessively hard
|
-true
|
|
|
T/F: Acetic acid is a useful addition to many compound fixatives because of its shrinking action
|
-false
-swelling |
|
|
T/F: Since formalin is a coagulant fixative it is considered an excellent fixative for paraffin embedding
|
-false
-formalin is noncoagulant |
|
|
T/F: Acetone is sometimes used when a rapid acting fixative is needed
|
-true
|
|
|
T/F: A fixative stops autolysis and putrefaction
|
-true
|
|
|
T/F: If tissues have been fixed in an aqueous fixative, uric acid crystals cannot be demonstrated
|
-true
|
|
|
T/F: A good fixative should penetrate slowly
|
-false
-rapidly |
|
|
T/F: If one wishes to prevent the formation of a pigment, formalin solutions must be buffered to a pH above 7.0
|
-false
-above 5.0 |
|
|
T/F: Concentrated commercial solutions of formaldehyde are 37%-40% by weight of the gas formaldehyde dissolved in water
|
-true
|
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|
T/F: Osmium tetroxide chemically fixes lipids
|
-true
|
|
|
T/F: Helly, Zenker, and Orth solutions all contian mercury
|
-false
|
|
|
T/F: Chrome pigment can be prevented by washing the tissues with water following fixation
|
-true
|
|
|
T/F: B-5 fixative contains formalin and potassium
|
-false
-formalin, mercuric chloride, sodium acetate |
|
|
T/F: Glutaraldehyde is frequently used to fix specimen for electron microscopy
|
-true
|
|
|
T/F: Orth solution is the best fixative for pheochromocytomas
|
-true
|
|
|
T/F: Heat and desiccation are methods of fixation
|
-true
|
|
|
What is the best fixative for connective tissue?
|
-Bouin solution
|
|
|
What is the best fixative for electron microscopy?
|
-osmium tetroxide
-Zamboni solution |
|
|
What is the best fixative for enzymme histochemistry on muscle?
|
-frozen section (no fixative)
|
|
|
What is the best fixative for immunofluorescence?
|
-frozen section (no fixative)
|
|
|
What is the best fixative for pheochromocytomas?
|
-Orth solution
|
|
|
What is the best fixative for phophotungstic acid hematoxylin (PTAH) for cross striations?
|
-Zenker solution
|
|
|
What is the best fixative for urate crystals?
|
-absolute alcohol
|
|
|
What fixative is made up of formaldehyde and mercuric chloride?
|
-B-5 fixative
|
|
|
What fixative is made with acetic acid, Helly solution, and picric acid?
|
-Bouin solution
|
|
|
What fixative is made with absolute alcohol, acetic acid, and chloroform?
|
-Carnoy solution
|
|
|
Which fixative is made with formaldehyde, dibasic sodium phophate and monobasic sodium phosphate?
|
-10% neutral buffered formalin
|
|
|
What fixative consists of 95% alcohol, acetic acid, formaldehyde, and picric acid?
|
-Gendre solution
|
|
|
What fixative contains formaldehyde, mercuric chloride, and potassium dichromate?
|
-Helly solution
|
|
|
Which fixative consists of acetic acid, copper acetate, formaldehyde, and picric acid?
|
-Hollande solution
|
|
|
What fixative is made with formaldehyde and potassium dichromate?
|
-Orth solution
|
|
|
What fixative is made with paraformaldehyde, picric acid, dibasic sodium phosphate, and monobasic sodium phosphate?
|
-Zamboni solution
|
|
|
What fixative contains acetic acid, mercuric chloride and potassium dichromate?
|
-Zenker solution
|
|
|
H and E stained sections fixed in formalin show a brown microcrystalline deposit lying on top of the tissue. This can most likely be prevented in the future by...
|
-raising the pH of the formalin above 6.0
|
|
|
H and E stained sections show a brown microcrystalline deposit lying on top of the tissue. It is especially heavy in bloody areas of the tissue. This pigment can most likely be removed by treating the tissue with...
|
-alcoholic picric acid
|
|
|
H and E stained sections FAIL to reveal uric acid crystals on a case with a clinical diagnosis of gout. One possible explanation for the false-negative result could be that the specimen was fixed in a solution other than...
|
-absolute alcohol
|
|
|
At the time of embedding, a white deposit is noted on tissue fixed in unbuffered zinc formalin and then transferred to phosphate-buffered formalin. One possible explanation could be that the tissue was...
|
-transferred to buffered formalin without washing
|
|
|
Blocked tissue, which had been fixed in Bouin solution, is pulled from the file after being stored for several years. New sections are cut and stained with H and E. No nuclear staining is noted on the new sections, although the original sections stained very well. The most likely explanation is that....
|
-picric acid was not remove sufficiently before blocking
|
|
|
Electron microscopic studies on a section of tumor fixed in 10% neutral-buffered formalin reveal very poor cell preservation. This could be prevented in the future by...
|
-fixing some of the tumor in glutaraldehyde solution
|
|
|
H and E stained sections of liver fixed in a saline solution in the microwave oven show marked distortion of the liver architecture and predominantly pyknotic nuclei. This most likely is the result of...
|
-overheating the saline
|
|
|
H and E stained sections of liver fixed in a saline solution in the microwave oven show marked pyknotic overstained nuclei. This can probably be prevented in the future by ensuring that the temperature is kept below...
|
-55 degrees
|
|
|
Microscopic examination of a PAS stained section reveals marked nonspecific staining. This could be caused by fixation in:
a) Bouins b) Gendre c) 10% NBF d) gluteraldehyde |
d) gluteraldehyde
|
|
|
The pathologist is sure that urate crystals were present in a tissue biopsy and should therefore be present in the H&E stained section, but polarization of the tissue is negative. This could be because:
a) application of the wrong stain for demonstrating b) poor cleaning and infiltration of the biopsy c) fact that urate crystals are not biofringent d) use of a water based fixative |
d) use of a water based fixative
|
|
|
Formaldehyde reacts primarily with which protein group?
|
Amino
|
|
|
During embedding, a white deposit is noted on several tissues. The tissue had been fixed in zinc-formalin, transferred to phosphate buffered formalin, dehydrated with 65%. 95%, and 100% alcohols, and cleared with xylene. One possible explanation of the white deposit could be that the tissue:
|
improperly washed between formalin solutions
|
|
|
Elector micrographs of a tissue section reveal electron-lucent membranes. This most likely indicate that
a) fixation was done in Bouin solution b) the osmolality of the fixative was incorrece c) the specimen was not post fixed in osmium tetroxide d) sections were stained with uranyl acetate |
c) the specimen was not post fixed in osmium tetroxide
|
|
|
Michel medium is
a) used for transporting unfixed tissue b) indicated for long term storage of fixed tissue c) a fixative with limites use d) an antigen retrieval solution |
a) used for transporting unfixed tissue
|
|
|
Microscopic evaluation of H&E stained sections from a surgically removed, formalin fixed small bowel specimen show an absence of much of the epithelium in otherwise normal tissue. This could be prevented by:
a) opening the specimen and adding fixative upon receipt b) avoiding the use of forceps during the dissection c) allowing the specimen to fix for 48 hours d) increasing the percentage of formalin in the solution |
a) opening the specimen and adding fixative upon receipt
|
|
|
Recently a laboratory’s primary fixative has been changed from neutral buffered formalin to an alcohol-based fixative promoted for antigen preservation. A marked difference in H&E staining is noted, with a marked increase in eosin uptake. This most likely results from the new fixative
a) creating a different tissue isoelectric point b) blocking protein precipitation c) generating more negative charges d) increasing cross-linking of the amino group |
a) creating a different tissue isoelectric point
|
|
|
Microscopic evaluation of a H&E stained section fixed in 10% NBF shows a complete absence of the surface epithelium and poor cellular detail in the lamina propria. This is caused by:
a) autolysis b) mechanical truma c) antemortem changes d) prolonged fixation |
a) autolysis
|
|
|
When sucrose is used to treat tissue for enzyme histochemical studies:
a) cell membranes are mobilized b) frozen sectioning is very difficult c) the tissue must be removed after a brief period of treatment d) the solution should contain 30% sucrose and 1% gum acacia |
d) the solution should contain 30% sucrose and 1% gum acacia
|
|
|
Kidney tissue had been submitted in Michel medium for immunoflourencence studies. Before the histotech performs the required studies, the tissue should be:
a) washed in PBS containing 10% sucrose b) frozen immediately unpon receipt c) placed in an aldehyde fixative d) refrigerated |
a) washed in PBS containing 10% sucrose
|
|
|
An isotonic solution for human tissue has an osmolality of approximately:
a) 500 milliosmols b) 340 milliosmols c) 260 milliosmols d) 150 milliosmols |
b) 340 milliosmols
|
|
|
Marked distortion of architecture and predominantly pyknotic nuclei are noted on H&E stained sections of kidney tissue. The tissue was fixed in the microwave in a saline solution. The problem could be prevented by
a) changing the processing schedule b) using another fixative solution c) carefully controlling the temperature d) using longer fixation times |
c) carefully controlling the temperature
|
|
|
Pafaffin blocks containing tissue fixed in Bouin solution are retrieved from storage after several years. New sections are cut and stained with H&E and no nuclear staining is present, although the nuclei of the original slides were well stained. To prevent this from happening in the future in tissue stored one must:
a) neutralize the picric acid before processing b) be sure that the pH of he bouin solution is neutral c) make certain that the formalin does not contain formic acid d) store the blocks in a facility with a maximum temperature of 20C |
a) neutralize the picric acid before processing
|
|
|
Microscopic examination of an H&E stained section fixed in formalin should show nuclear bubbling. This can be avoided by:
a) extending the length of fixation b) fixing at refrigerator temperatures c) changing the pH of the fixative d) decreasing the osmolality of the fixative |
a) extending the length of fixation
|
|
|
During the examination of an electron microscope print, it is noted that leaching of cellular material has occurred and that the cytomembrane appears to be bubbling. This problem is most likely caused by fixing the tissue in osmium tetroxide for:
a) 1 min b) 30 min c) 1 hour d) overnight |
d) overnight
|
|
|
Which of the following fixative is stable at room temperature?
a) paraformaldehyde-gluteraldehyde b) 2-3% gluteraldehyde c) Zamboni PAF d) 1% buffered osmium tetroxide |
c) Zamboni PAF
|
|
|
The papraformaldehyde in Karnovsky paraformaldehyde-gluteraldehyde solution must be heated to 60C prior to adding 1M NaOH in order to:
a) dissociate the daraformaldehyde b)purify the gluteraldehyde c) polymerize the gluteraldehyde d) eliminate the gasses present |
a) dissociate the daraformaldehyde
|
|
|
Prior to processing, tissue fixed in gluteraldehyde for electron microscopy should be:
a) post-fixed in formaldehyde b) rinsed with gum sucrose c) post-fixed in osmium tetroxide solution d) rinsed with an alcohol buffer solution |
c) post-fixed in osmium tetroxide solution
|
|
|
Poor fixation of electron microscopy specimens will be indicated by the appearance of:
a) evenly dispersed ground substance b)stabilized cytoplasmic proteins c) displaced mitochondrial membranes d) unaltered nuclear and cytoplasmic membranes |
c) displaced mitochondrial membranes
|
|
|
Formalin pigment may be removed from microscopic sections by treating them with
a) Lugols iodine and sodium thiosulfate b)potassium permanganate c) dilute acetic acid d) potassium hydroxide in 80% alcohol |
d) potassium hydroxide in 80% alcohol
|
|
|
Fixatives producing covalent bonding that tends to mask antigenic site and hamper immunohistochemical localization of antigens contain:
a) mercury b) phosphates c) aldehydes d) alcohol |
c) aldehydes
|
|
|
For which of the following techniques are frozen section of fixed tissue preferred?
a) autoradiography of steroid hormones b) enzyme histochemistry of muscle biopsies c) fat stain of liver d) florescent antibody techniques |
a) autoradiography of steroid hormones
|
|
|
The difference between Orth and Helly solution is that ONLY helly contains:
a) formaldehyde b) potassium dichromate c) mercuric chloride d) acetic acid |
b) potassium dichromate
|
|
|
A small biopsy is submitted with a request for stat acid fast and fungus stains. The tissue should be fixed in:
a) Zenker b) Carnoy c) B-5 d) buffered formalin |
d) buffered formalin
|
|
|
A microwave oven can be used for fixation because:
a) causes a cross linking of proeins b) induces physical fixation c) increases tissue basophilia d) inactivates enzymes with beta radiation |
b) induces physical fixation
|
|
|
Unstained slide from B-5 fixed tissue should be treated with which of the following staining?
a) lithium carbonate b) potassium iodide c) sodium bisulfite d) iodine |
d) iodine
|
|
|
Microscopic evaluation of a tissue section reveals a brown pigment lying on top of the tissue. Adjacent sections are treated with:
Iodine and sodium thiosulfate Potassium ferrocyanide and hydrochloric acid Saturated alcoholic solution of picric acid All sections still show the brown pigment. This pigment could have resulted from improper washing following fixation in a) Zenker b) formalin c) B-5 d) bouins |
a) Zenker
|
|
|
A possible rhadomyosarcoma is brought to the lab for appropriate fixation. For the nonimmunochemichal stains neeed to confirm this tumor, at least one section should be fixed in:
a) Orth b) Bouin c) Zenker d) buffered formalin |
c) Zenker
|
|
|
Tissue fixed in osmium tetroxide must be:
a) washed with running water b) cut very thin for fixation c) fixed overnight before processing d) processed on a short cycle |
b) cut very thin for fixation
|
|
|
When osmium tetroxide is used on a kidney biopsy for ultrastructural studies, the time of fixation:
a) is not critical b) should be 1 hour or less c) prolonged because of tissue density d) depends on the fixative concentration |
b) should be 1 hour or less
|
|
|
Helly fixative prepared 3 weeks previously is now discolored and turbid. The most likely reason for this is
a) the presence of acetic acid in the fixative b) improper solution buffering c) the premature addition of formaldehyde d) chemical oxidation |
c) the premature addition of formaldehyde
|
|
|
A stained microscopic section shows marked lysis of erythrocytes, amorphous brown pigment lying on top of the section, and pale nuclear staining. These results indicate improper treatment after fixation in
a) formalin b) Helly c) Zenker d) Orth |
c) Zenker
|
|
|
A small amount of white precipitate is noticed in the bottom of the lab stock of 37-40% formaldehyde. The most appropriate action is to:
a) discard the solution b)disregard the precipitate c) acidify the solution slightly d) add methanol to the solution |
b)disregard the precipitate
|
|
|
Acetone can be used to fix tissue for the demonstration of:
a) myelin sheaths b)phospholipods c) oxidoreductases d) cell surface antigens |
d) cell surface antigens
|
|
|
A tissue block of unfixed hemorrhagic spleen is fixed for 24 hours in formalin that was prepared 6 months previously. Subsequent H&E stained sections show a granular black pigment on the surface of the tissue. This problem can most likely be prevented in the future by:
a) washing the tissue before fixing b) ensuring that the formalin contains buffering reagents c) using an iodine solution on the processor d) using only freshy prepared solutions |
b) ensuring that the formalin contains buffering reagents
|
|
|
Zenker fixation is critical for a nonimmunolohistochemical special stain used in the diagnosis ofwhich of the following tumors?
a) liposarcoma b) fibrosarcoma c) neurosardoma d) rhabdomyosarcoma |
d) rhabdomyosarcoma
|
|
|
Tissue is received in Zenker fixative. After 72 hours of fixation, it is washed in running water for 12 hours, then routinely processed and stained with H&E. The nuclei appeared very poorly stained. This can be corrected in the future by:
a) increasing the blueing time during staining b) extending the washing time before processing c) decreasing the fixation time d) minimizing the slide drying time |
c) decreasing the fixation time
|
|
|
A gouty tophus is seen in a fresh tissue specimen. The ideal fixative for the crystals which may be occurring with this condition is:
a) buffered formalin b) Bouin c) absolute alcohol d) Orth |
c) absolute alcohol
|
|
|
To ensure adequate fixation, a colon polyp measuring approximately 2*2*3 cm should be placed in, at the minimum, what volume of fixative?
a) 2.4 mL b) 24 mL c) 240 mL d) 2400 mL |
c) 240 mL
|
|
|
A characteristic of acetone fixation is that:
a) glycogen is removed from tissue b) enzymes are removed from tissue c) the tissue is overhardened d) antigen-antibody reactions are destroyed |
c) the tissue is overhardened
|
|
|
A wet tissue sample has been requested for electron microscopy. All available tissue has been fixed in Bouin solution, washed, and stored in 70% alcohol. Electron microscopy on the tissue would show:
a) good fixation of nucleoproteins b) well-preserved organelles c) some shrinkage of the nucleolus d) inadequately preserved ultrastructures |
d) inadequately preserved ultrastructures
|
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A surgical specimen is obtained from a patient with diagnosis of probable metastatic malignant melanoma. The choice of fixatives should be compatible with use of which of the following special stains or diagnostic procedures?
a) colloidal iron b) immunohistochemistry c) immunoflourescence d) digestion procedures |
b) immunohistochemistry
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A section of sheath tendon has been fixed in 10% NBF for 24 hours, routinely processed, and embedded in paraffin. The demonstration of urate crystals on section from this block:
a) should be performed after post-fixation b)will be best with a fluorescence technique c) must be performed on air dried sections d) will not be possible due to improper fixation |
d) will not be possible due to improper fixation
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When Helly solution is used as a fixative, it is necessary to remove which of the following from the sample
a) mercury crystals b)picric acid c) formalin pigment d) iron pigment |
a) mercury crystals
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A section of healthy adrenal gland to be used as a control for chromaffin granules is fixed in osmic acid for 8 hours. When examined microscopically, no granules are demonstrated. Thisproblemcan be resolved in the future by:
a) washing the tissue before staining b) selecting another tissue for the control c) using another fixative d) increasing the fixation time |
c) using another fixative
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An aqueous fixative MUST be chosen for sections that require:
a) the preservation of lipids b) rapid sample fixation c) maximum hardening d) preservation of amyloid |
a) the preservation of lipids
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One of the functions of fixation is to:
a) form insoluble tissue salts b) inhibit autolytic enzymes c) adjust the nuclear/ cytoplasmic ratio d) maintain a neutral pH |
b) inhibit autolytic enzymes
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Pap smears that have been fixed with a spray fixative are submitted to the lab. They smears are stained without an other treatment. The most likely result will be:
a) excellent cytological detain b) the loss of cells from the slide c) cells showing air-drying artifact d) nuclei that appear foggy and lack detail |
d) nuclei that appear foggy and lack detail
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Paraffin blocks of Bouin fixed tissue have been stored for 2 years. Results of current tests show very poor H&E staining and some structural deterioration. However, the original sections from the blocks show excellent preservation and staining. The changes are most likely due to:
a) Excessive heat during embedding b) residual picric acid in the block c) freezing of blocks during storage d) physical changes in the paraffin |
b) residual picric acid in the block
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a solution prepared in water
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aqueous
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When left alone concentrated formalin may develop a white precipitate called
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paraformaldehyde, a polymer of formaldehyde.
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What is the safest thing to do when a white precipitate forms in formlin
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ignore it or filter it
do NOT heat |
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The greatest binding for formaldehyde is at a pH of
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7.5-8.0
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What forms between the side amino groups of lysine and glutamine on different protein chains in formalin
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methylene bridges
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It penetrates quickly but fixes very slowly.
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formalin
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Add ------ to formalin to get correct osmolality
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sodium chloride
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It causes less shrinkage than other fixatives, but hardens more than all other fixatives except alcohol and acetone.
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formalin
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What types of formalin mixtures are good for electron microscopy
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Millonig and paraformaldehyde
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Good cytoplasmic fixative
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formalin
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Major use precipitate DNA; preserve/ coagulates nucleoproteins
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acetic acid
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It is added to fixative because it fixes nuclei and precipitates DNA.
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acetic acid
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This fixative improves acid dyes
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acetic acid
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Leaves tissue soft
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acetic acid
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It dissolves some cytoplasmic organelles and deposits
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acetic acid
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This preserves phospholipids
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Calcium Formalin
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use this fixative for the Cajal astrocyte stain
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Formalin Ammonium Bromide
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pH1.5 very acidic type of formalin fixative
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Formalin Ammonium Bromide
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This fixative fixes and dehydrates. Tissue can be stored indefinitely in this.
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Alcoholic Formalin
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GOOD for electron microscopy because it preserves ultrastructure.
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Gluteraldehyde
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NOT good for PAS reaction because it will give false positive result (b/c free aldehyde group)
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Gluteraldehyde
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It fixes and penetrates slowly so tissue must be thin
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gluteraldehyde
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this fixative breaks down on exposure to oxygen
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gluteraldehyde
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This overhardens tissue, must transfer → a buffer solution after 2 hours
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gluteraldehyde
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Gluteraldehyde buffer solution and pH
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phosphate buffered gluteraldehyde pH 7.2-7.4)
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Fixes very quickly and does not cause some artifacts, no antigen retrieval is needed
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Glyoxal
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Very toxic/corrosive, but excellent morphology preservation and trichrome stains, it is always used in a mixture of fixatives
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Mercuric Chloride
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Do not use metal objects when handling this fixative
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Mercuric Chloride
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It enhances staining by leaving tissue very receptive to dyes.
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Mercuric Chloride
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It penetrates poorly and shrinks
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Mercuric Chloride
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It prevents freezing, so frozen sections are difficult to cut, what must be done
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Mercuric Chloride
treat the tissue with iodine, hypo, and water before freezing |
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Preserves organelles
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Mercuric Chloride
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pigments CANNOT be prevented, only removed
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Mercuric Chloride
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Only zinc has been a good replacement
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Mercuric Chloride
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GOOD as a post fixative for electron microscopy because it preserves ultrastructure.
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Osmium Tetroxide
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GOOD for lipid preservation blackens lipids
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Osmium Tetroxide
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It only penetrates a few layers at a time, so sections must be very thin.
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Osmium Tetroxide
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It makes tissue cytoplasm have less affinity for anionic (acid) dyes, but it will make it readily accept basic dyes.
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Osmium Tetroxide
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It interferes with staining
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Osmium Tetroxide
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Tissues must be washed very well with running tap water
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Osmium Tetroxide
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Both a fixative and a dye
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Picric Acid
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It causes extreme shrinkage and must be wasted out with alcohol (+lithium carbonate) before processing
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Picric Acid
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tissue will be distorted if it is not completely washed out
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Picric Acid
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Do NOT use for DNA or RNA stains
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Picric Acid
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Good fixative for glycogen ?
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Picric Acid
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It will decalcify tissue with small deposits of calcium
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Picric Acid
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It will leave tissue very receptive to acid dyes
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Picric Acid
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MUST keep moist or it will explode
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Picric Acid
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This solution has a pH of just over 4, if the pH drops it will become acidic and act like chromic acid.
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Potassium dichromate
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Preserves chromaffin granules (Orth)
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Potassium Dichromate
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It fixes slowly leaves tissue soft
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Potassium Dichromate
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It preserves mitochondria
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Potassium Dichromate
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Improves acid dyes, reduces basic dyes
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Potassium Dichromate
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It preserves lipids, but not as well as osmium tetroxide
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Potassium Dichromate
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Excess fixative must be removed from specimens before placing them in dehydrating solutions
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Potassium Dichromate
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Proteins are coagulated, and so is nucleoprotein
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chromate
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DNA is precipitated and hydrolysed, so that a Feulgen reaction may be positive without using hydrochloric acid
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chromate
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Pigments for when the tissue it taken from-------- to alcoholic solutions- excess ----- should be removed by washing before processing
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chromate containing solutions
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Use for hematopoietic and lymphoreticular tissue (lymph node &bone marrow)
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B-5
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Good nuclear detail
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B-5
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Treat for mercury pigments, no need to treat for formalin pigment
→After fixing store in 70% alcohol |
B-5
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Good for trichrome stains (gi biopsy & connective tissue)
frequently used for endocrine tissues |
Bouins
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Good nuclear and cytoplasmic preservation, better than NBF
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Bouins
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Lyses red blood cells
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Bouins
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Iron and calcium deposits are dissolved
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Bouins
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→After fixing, wash well with alcohol (+ lithium carbonate)and Treat for formalin pigments
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Bouins
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If not washed out, the picric acid will cause the tissue to deteriorate over time
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Bouins
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Good for preserving carbohydrates especially glycogen because the alcohol traps it
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Gendre
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→After fixing, wash well with alcohol (+ lithium carbonate)and Treat for formalin pigments
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Gendre
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This will decalcify small bone in tissue
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Hollande
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The copper stabilizes red blood cells, so less lysis occurs
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Hollande
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GOOD nuclear fixative --------fixed tissues stain brilliantly
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Zenker
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USE for Mallory PTAH
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Zenker
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If asked to cut cryostat sections of tissue fixed in -------solution, the histotechnologist should:
treat the tissue with iodine, hypo, and water before freezing |
Zenker
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DO NOT use for silver staining
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Zenker
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Makes H&E more acidophilic cytoplasmic preservation (too long fixing makes tissue over hard and less basophilic)
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Zenker
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This will decalcify small needle bone in tissue
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Zenker
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→Tissue must be washed in running water after fixation (before processing) ,If not washed properly potassium dichromate will cause chrome pigments
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Zenker
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Add formaldehyde right before use, if not the solution will become dark and turbid
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Helly
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Will NOT cause red blood cell lysis
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Helly
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DO NOT use for silver staining
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Helly
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Makes H&E more acidophilic cytoplasmic preservation (too long fixing makes tissue over hard and less basophilic)
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Helly
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Treat for mercury pigments and formalin pigments →store in alcohol
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Helly
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Formaldehyde is a reducing agent, while potassium dichromate is an oxidising agent. The reaction between them is relatively slow and mixtures containing both are not unusual. These solutions deteriorate so they should be prepared immediately before use and fixation in them should not be extended.
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Helly
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Good for adrenal, medulla, pheochronocytoms (tumor of the adrenal gland)
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Orth
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Will show demonstration of chromaffin granules
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Orth
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post fix with osmium tetroxide
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Zamboni
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Good for electron microscopy pH 7.3
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Zamboni
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It enhances nuclear and cytoplasmic fixation
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Zinc Formalin
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Shrinks tissue more than NBF
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Zinc Formalin
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Fixes quickly
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Zinc Formalin
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Immunoreactivity in paraffin embedded tissueis superior to NBF
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Zinc Formalin
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Fixes 1.5 times faster than aqueous solutions
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Alcoholic Zinc Formalin
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Increase autoflourecence if in sucrose PBS too long
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Michel Solution
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Wash tissue in PBS containing 10% sucrose after
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Michel Solution
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For unfixed tissue Short term storage
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Saline Solution
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Preserves glycogen and urate crystals (gout)- water soluble tissue components
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alcohol
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Preserves most pigments
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alcohol
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Transfer to ethanol
Good nuclear preserver Use for cytology Preserves glycogen |
Carnoy
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Good for microanatomical preservation & H&E
good nuclear preservation |
Clarke
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Used on frozen sections for cell surface antigens by IHC and for enzyme histochemistry
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Acetone
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Fixes quickly at a cold temp
Used as a fixative for brain tissue- rabies |
Acetone
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Shrinks
Distorts Overhardens |
Acetone
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