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32 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Sections expand or disintegrate on water bath |
Poor impregnation. Reprocess tissue Water temp. Too high in float bath |
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Sections roll into a coil instead of remaining flat on knife edge |
Blade dull.. Use new blade Rake angle too small... Reduce tilt if clearance angle is excessive Section too thick |
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Grooved. Scored. Smeared. Deformed sections |
Dull blade or knife edge Too warm room |
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Sections fail to form ribbons |
Knife is dull Knife tilted too much Paraffin wax too hard Sections too thick Surface and block edge is not parallel. Trim Horizontal surface of block is not parallel to the knife. Reorient and readjust block |
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Sections roll up on cutting so that they adhere and get broken against knife edge |
Knife is blunt Tilt of knife too great Knife is dirty |
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Ribbon is curved crooked and uneven instead of straight |
Blunt of dull spot on the knife producing irregular knife edge. Adjust the knife so that knife edge will produce a sharp edge presenting a uniformly sharp edge to the block or sharpen Edge of the block is not parallel but round or wedge shape. Retrim Knife not parallel to block. Readjust knife and block Paraffin is impure. Repeat impreg with pure wax |
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Sections are compressed, wrinkled, or jammed |
Knife tilt too vertical Knife is coated Knife is dull Warm paraffin block or soft Warm room Microtome set screw is loose Unparallel block edges. Trim Sections too thin Too rapid cutting |
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Sections are squashed (width of sections is less than block) |
Bevel is lost due to incorrect sharpening |
Resharpen using knife back or automated sharpener |
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Hole formed in section |
Bubble or dirt in embeding medium. Reembed with filtered wax Calcium. Base sledge with wedge knife Excess dehydration or Improperly processed tissue. Expose in ice water or cotton |
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Sections of unequal thickness are produced |
Tilt of knife too great (Bevel not cleared hence object compressed against knife edge) Clamp set screw on knife or blockholder is loose Block is large Block is hard. Phenol or detergent |
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Sections adhere to the knife or other parts of microtome |
Static electricity due to low.atm. humidity Knife is dull Knife is dirty Knife is titlted too great |
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Ribbon is split, lengthwise vertical scratches seen on sections |
Nicks or damage on the knife edge Dirty embeding medium Dirty knife Tilt of knife too great |
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Resistance is felt on the lower part of the section during cutting |
Tilt of knife is too small, Paraffin block is compressed against base of knife towards end of stroke |
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Horizontal or parallel lines or furrows across the section (chatters) are seen, forming thin and thick zones |
Knife vibrates due to hardness. Treat with phenol or collodionize Knife is dull Knife tilt to great Overhydration or lack of moisture on tissue. Ice water or ice tray Cutting quickly |
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Sections cut is sometimes thick or thin |
Knife is blunt Knife tilt is too great Knife tilt is too small that block is compressed by bevel and section not cut Knife not clamped properly Knife or blockholder is loose |
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Knife makes a hard metallic scraping or ringing sound on backstroke when section is cut |
Tilt of knife is too slanted or big Tissue is too hard Knife blade too thin |
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Frozen tissue crumbles and comes off the block holder when cut |
Freezing is not adequate. Refreeze |
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Frozen tissue chips into fragments when cut |
Tissue is frozen too hard. Warm with fingers |
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Pleated. Folded. And crooked ribbons |
Imperfections on the blade edge, ie the horizontal edges are not parallel or the lower block edge is not parallel to the knife edge when sectioning Remedy Trim the block parallel to the other edge Or reembed them in molds so that the edge of the block is parallel to the knife edge Try another part of the knife edge |
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Sections are lifted from the knife on the upstrokes |
Knife tilt too great Knife is dull Paraffin wax is too soft or room is warm |
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Brittle or hard tissues |
Drying out of tissue before fixation Prolonged fix dehy clear impreg Overheated paraffin oven
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Water with detergent. Phenol. Molliflex |
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Clearing agent turns milky as soon as tissue is placed in it |
Incomplete dehydration. Repeat dehy with absolute alcohol then clear again |
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On trimming, tissue smells of clearing agent |
Clearing agent not completely removed due to insufficient impreg. Block is trimmed. Remaining wax is melted on oven and impreg is repeated. Change paraffin once before blocking |
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Tissue is opaque, section cutting is difficult due to alcohol |
Insufficient clearing. Clear again. If embedded, prolong clearing up to 12 hrs. Then reembed |
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Tissue shrinks away from wax when trimmed |
Insufficient dehy. Then incomplete clearing and impreg. Repeat whole proc. |
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Tissue is soft when block is trimmed |
Incomplete fixation. Rpeat whole proc. |
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Airholes found during trimming |
Incomplete impreg. Repeat impreg |
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On trim. Wax appears crystalline |
Contaminated wax. Reembed in filtered wax Block not cooled rapidly enough |
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Paraffin moist and crumbles after cooling |
Insufficient paraffin impreg. Repeat paraffin impreg and reembed |
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Inadequate processing of fatty tissues |
Routine sched and reagents may not process fats adequately. Fats shkuld be cut thibly. Use alcohol. Weak Use Acetone or isopropanol Then final absolute ethanol |
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Hard dense tissues |
Tough keratin component Treat fixed tissues with 4% aq. Phenol for 24 to 72 hrs |
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On embedding. Tissue is soft and mushy at center |
Inadequate processing due to very thick or fat sections. Cut thin sections of fat. Ensure complete fix. |
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