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UND 362 DC and Gross
| Question | Answer |
|---|---|
| What general info is given during grossing | ID, fresh v FS, diagrams and margins, pin out specs, remove clips, wrap small specs |
| what is the typical thickness/dimension that a spec should be when grossed in? | 3mm thick with 2mm buffer w/in cassette |
| what are the special prep specs in grossing | FS, micro, photographs, E/M with fix of gluteraldehyde or paraformadehyde, chromosome analysis, calculi, hormone receptors |
| what are the rush specs in grossing | endoscopic bx's, transplant tissues, transplant rejection tissues |
| what is the typical fixative in grossing and 3 special ones | formalin, bouins for trichrome, zenkers for PTAH, and B5 for bone marrow |
| What can be done with fatty tissue to clear | use acetone, but it will alter nuclear morphology |
| what should be avoided with decal pertaining to bone | avoid bone with soft tissue |
| what is ink used for in grossing | orient surface, margin, sides; proximal and distal margins;all margins on breast inkend darker colers work better with microscope |
| what should be avoided when inking | areas containing an lesion |
| how many measurements are taken during gross | 2 or 3 dimensions (or aggregate), smallest to largest diameter |
| what are some of the histology terms used in grossing pertaining to sections? | cross section, transverse section, longitudinal section, on edge, on end, en face, cut side down |
| Pertaining to legal issues in histology name a couple socially sensitive and a likely forensics spec (and what must be done with it) | socially (POC, abortions) forensics - bullets, must follow chain of custody and MUST NOT be let unattended |
| how are skins cut | Punchs are bisected larger than .5cm dia |
| Lymph nodes are typically for? and for what specs | FS, micro, Touch prep, flow, cytogenetics, hormones, biochem assay (mostly from breast,prostate, colon |
| what is the proper dimensions bone | 3-5mm (not less than 2 or it will release from paraffin) |
| dense bone v porous will take what timeframe | dense bone will take longer than porous |
| what is the typical fixative for bone | formalin (not recommended to use alcoholic formalin or 70% alcohol because it will slow the process) |
| what is the positive and negative for using zenkers with bone marrow | dual purpose fix and decal, but it can dissolve iron and contains mercury (mercury pigment). it will also cause radiopacity. |
| what is the best way to set the cassettes in decal | suspend or set on gauze (do not place flat on botton, all sides should be exposed) |
| what must be done with decal'd bone before putting it in formalin? | MUST be washed or the decal (hcl) and formalin will cause bis-chloromethyl ether |
| what fixative can be used for bone and what must it be placed in afterwards | picric acid (but must go directly into alcohol) |
| name 4 decal agent properties | speed, prevent cell damage (via acid), preserve tissue morphology, change stain ability of tissue |
| List 4 decal methods | Acid, chelating, ion-exchange, electrical ionization (microwave) |
| what happens during acid decalcification | calcuim salts (carbonate and phosphate) dissolve and then ionize (ie gain pos. or neg. charge) when exposed to acids |
| at what ph is calcium soluble at | 4.5 |
| name the 2 strong acids for decal and 4 properties | nitric or HCL INORganic, rapid, recommended conc. 5-10%, affects stainibility (time must be monitored) |
| name 3 weak acids and give 2 properties | formic, acetic, picric ORGanic, slow but gentle |
| what is the proper decal method | wash-dc-check dc (chemically or via bone), wash, if not full dc replace solution and repeat until done, WASH |
| what are four common descripters for using formic acid as a DC? | its common, slow, weak, organic |
| name the 6 formic acid decalcifiers | lilly, evans & krajian, Kristensens, Gooding and Stewart, Commercial (eg immunocal), and one with no name |
| what is the formula for lilly DC | 5% formic acid (works ok at room temp but at 37○C (98○F) it will interfere with staining) |
| what is the formala for evans and krajian DC | 25% formic acid and 10% sodium citrate |
| what is the formula for Kristensens DC | sodium formate and formic acid |
| what is the formula for gooding and steward DC | formic acid and formalin |
| what is a formic DC formula that doesn't have a trademark | 8% formic acid and 8% HCL |
| How are HCL and Nitric Acid DC's in terms of speed | They are rapid DC |
| Using HCL DC at 37○C will affect eosin, alum/weigerts hematox, feulgen and azure eiosin stains | Eosin will be OK, Alum/Weigerts will be impaired, Feulgen will not work, and azure eosin will give pink cytoplasm and nuclear stain |
| using HCL DC at 55○C will cause what | lost of Ca salt and hydrolysis of bone matrix |
| HCL DC will cause what and how can it be prevented | hcl will cause tissue swelling, it can be prevented by adding chromic acid, alcohol, or NACL to the HCL |
| List 3 HCL DC formulas and their formula | von ebers (Hcl/sodium chloride), richman-gelfand-hill (formic/HCL), commercial DC's containg hcl |
| give 4 facts about Nitric acid as a DC | rapid, best after formalin fixation, will impair nuclear staining after 48 hrs, will produce an unsatisfactory geimsa stain |
| What are the 4 Nitric acid DC formulas | 5-10% aqueous nitric acid, perenyis fluid (10% nitric acid, alcohol, chromic acid), 5% nitric acid/formalin, Commercial nitric DC |
| What is chelating DC | organic (binding w/ metals) |
| give 4 facts pertaining to chelating DC | slow but gentle, doesn't damage tissue or ability to stain (therefore good for EM and IHC/enzymes, takes 2-4 days for 3mm section, exact ph not critical |
| how does chelating work? | EDTA binds calcium ion from outer shell of apetite crystal (which gets reduced) |
| How does Ion exchange work for DC | ammoniom ions are exchanged for Ca ions (formic acid remains clear of Ca |
| Describe visually what an ion exchange setup would look like | glass jar with 10-20% resin (ammoniated salt) on the bottom and 80-90%formic acid on top (with bone laying on top of resin |
| what are the advantages of using ion exchange resin for DC | good preservation, eliminates daily changes, resin can be reclaimed |
| describe using electrical ionization for DC | (rarely used), elect. current to solution, the current draws the neg. calcuim to the + carbon cathode |
| what are two disadvantages to using electrical ionization | heat is generated therefore potential damage, limited specs can be done at a time |
| what are 3 positives and 1 possible drawback to using a microwave for DC | can fix and DC, reduced time, consistent slides be careful not to OVER decalcify |
| give 7 factors affecting DC rate | conc. and volume, temp, agitation, suspension, type of bone, spec size, patients age. |
| how does concentration and volume affect dc? | increased conc. will decrease the DC time but will increase staining problems. (use large volumes for multiple specs) |
| how does temp affect DC | increase temp will decrease time but will increase staining problems (it is best at 20-25○C) |
| what are the two types of bone and how would they affect DC | cortical (hard), cancellious (spongy) bone. Harder bone would take longer |
| what are the 5 ways that the DC endpoint can be determined | xray (most accurate), chemical (accurate), physical (possible damage), weight loss/gain, bubble test |
| how can you use a chemical to check for dc end pt. | take 5ml of each (dc fluid, 5% ammonium hydroxide, 5% ammonium oxalate) check for turbidity (if precipitate then DC not complete, change DC) |
| what are 4 facts about using xray to check for dc end pt | uses visible evidence (pre and then post xray), expensive, BEST METHOD, can't be used with zenkers or B5 fixed bone because they have mercuric chlorid which will cause radiopacity |
| how is DC checked physically | done by probing or bending (not recommended because it can cause artifacts and is innacurate) if done probing side of spec is best |
| how is the bubble technique used to test DC endpoint | acid (with calcuim) will cause bubble formation, jar is shaken to remove, when no bubbles are present DC is done (UNRELIABLE) |
| How can weight loss/gain be used to check dc endpoint | weigh bone, DC, weigh (weight loss will = Ca loss, DC in fresh soln', repeat until their is weight gain indicating that there is water uptake in the bone |
| How is surface DC done during microtomy | (when DC not complete or soft tissue has Ca deposit) 1. rough cut block 2. put block face down in DC for 15-60 min., wash, resection |
Created by:
mustangvxd
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