Chapter 2: Processing
All of the following reagents can be used to dehydrate tissue EXCEPT: Benzene, absolute alcohol, dioxane, or acetone
Benzene
Which of the following will most likely be corrected by soaking a faced block in ice water?
A. Lengthwise splits in the sections
B. Compressed and jammed sections
C. Microscopic chatter
D. Mushy sections
C. Microscopic chatter
Which of the following is an explosive compound that should not be stored in the lab?
A. mercuric chloride
B. anhydrous picric acid
C. glacial acetic acid
D. chloroform
B. Anhydrous picric acid is very explosive and should always contain at least 10% moisture
T/F: When undecalcified bone is to be sectioned, it must be embedded in Carbowax?
False. Carbowax does no provide enough support for undecalcified bone; it must be embedded in glycol methacrylate
Which fixative reacts with lipids by preserving them but with gradual loss?
Formaldehyde or Paraformaldehyde
All of the following chemicals are clearing agents EXCEPT: Chloroform, Dioxane, Ethanol, or Xylene?
Ethanol. Ethanol is a dehydrating agent and it will not clear tissue.
A biopsy of which of the following tissues should be sectioned at 2 micrometers?
A. Bladder
B. Heart
C. Kidney
D. Liver
C. Kidney
Which of the following types of extinguishers should be used on a fire involving xylene?
A, B, C, Or D?
Type B. Or those involving flammable liquids and gases; they require that oxygen be blocked from the fuel in order to be extinguished.
A type "A" fire extinguisher should be used on fires involving?
A. Paper/Wood
B. Electrical equipment
C. Hydrocarbons
D. Reactive metals
A. Fire extinguishers include water based, foam or loaded stream, and multipurpose dry extinguishers; these are used on fires involving combustible materials such as wood, plastics, etc
Which fixative is excellent for use on biopsy specimens of the gastrointestinal tract and why?
Bouin because the nuclei are much crisper and better stained than after fixation with 10% NBF.
T/F: Sections processed by the celloidin method shows less shrinkage than when processed by the paraffin technique
TRUE. Because no heat is involved, sections processed by the celloidin method shows less shrinkage than with the paraffin technique.
Which of the following blade profiles is recommended for frozen sections?
A. Biconcave
B. Planoconcave
C. Low
D. High
D. High
The left blue diamond in the NFPA chemical hazard label provides information on which of the following?
A. flammability
B. reactivity
C. special warnings
D. health hazards
D. Health Hazard
Paraffin processing is contraindicated for the subsequent demonstration of?
A. Enzymes
B. Mucins
C. Nuclei
D. Proteins
A. The heat used in paraffin processing will destroy enzymatic activity.
What is the make up of Hollande Solution?
Copper acetate: 25g
Picric acid: 40g
Formaldehyde: 100mL
Acetic acid: 15mL
Distilled water: 1,000mL
Of the reagents listed below, the BEST substitute for ethanol for processing tissues is? Dioxane, Butanol, Isopropanol, methanol.
Isopropanol
When cutting 30 micrometer sections of fixed brain tissue in -20C cryostat, the sections fragment at the blade edge. This problem could most likely by prevented by:
A. lowering the cryostat temp to -30c
B. Raising the cryostat temp to -7c
C. Freezing the tissue in liquid nitrogen
D. Using the anti-roll plate
B. Brain tissue cuts most easily at -7C to -10C, so the temperature of the cryostat should be raised.
CAP and NFPA define the maximum working volume (gallons) of flammable liquids (Class I, II, & III) allowed per 100ft2 outside a storage cabinet as?
A. 1
B. 3
C. 5
D. 10
A. Flammable and combustible solvents with flashpoint <200C allowed outside of a storage cabinet as 1 gallon per 100ft
T/F: Methylene blue can be use in the processing alcohols to dye tissues for identification when embedding?
True
Which of the following groups of special stains requires sections cut at 8-10 micrometers?
A. Congo red, Lieb crystal violet, Bielschowsky
B. Kinyoun, Snook, oil red O
C. von Kossa, Fontana-Masson, Sudan black B
D. Verhoef-van Gieson, aldehyde fuchsin, Masson trichome
A. stains for amyloid (Lieb crystal violet, Congo red) and for several neural stains (Bielschowsky) require sections cut a 8-10 micrometers
Microscopic review of H&E stained sections of a colon biopsy show very uneven staining of the tissue and poor nuclear detail. Of the following, the most likely cause is that the:
A. paraffin block was cooled too slowly
B. Tissue remained in alcohol too long
C. pH of the fixative was incorrect
D. Clearing agent is contaminated
D. When the tissue still contains water after clearing steps are complete, the staining results may be uneven staining and poor nuclear detail.
Which of the following could be substituted for gelatin as an additive to the flotation bath?
A. Aminoalkylsilane
B. Chromium potassium sulfate
C. poly-L-lysine
D. Agar
D. Agar
Monitoring of formaldehyde exposure shows the STEL to be 2.0ppm. This means that:
A. No further monitoring needs to be done
B. Monitoring must be repeated in 30 days
C. A medical surveillance program must be established
D. Any action depends on the time weighted average (TWA) and action level
D. Maximum allowable STEL for formaldehyde is 2, so no action would be taken based on this. Any action depends on the TWA for an 8 hour shift or on the action level
When used for clearing, cedarwood oil must be followed by:
A. Alcohol
B. Xylene
C. A universal solvent
D. Paraffin
B. Xylene.
All of the rules concerning fixation with potassium dichromate must be followed. Name the 3.
The tissue must be washed after fixation, the time of fixation must be controlled, and the remaining wet tissue must be stored in 70% to 80% alcohol.