Log Book Abbreviations

One of our responsibilities as Mohs techs is to make sure the slide labels and logbook information is correct and CLIA compliant. Here are the most commonly abbreviated orientation and directional terms:

The following terms should never be abbreviated in the logbook or label, even if its written shorthand on the map:

Less common directional terms (eg. pareital, distal, radial, ulnar, dorsal, etc) should be written out as well. If you see any abbreviated term on a map that you are unsure of, ask the staff what it stands for and write out the whole word  in the logbook/labels.

TROUBLESHOOTING: Cry-Ac

Problem: Trigger handle sticks open, won't stop spraying.
Solution: Rotate the trigger to the side until the next time you need to use it. If this doesn't work, depressurize it by unscrewing the top.

Problem: Excessive leaking/hissing from the relief valve.
Solution: The exterior of the Cry-Ac has too much frost built up. Try pushing down on the relief valve and twisting it back and forth to break up the ice. You can also clean the frost with alcohol and gauze.

Problem: Sprays only intermittently.

Solution: The liquid nitrogen supply may be contaminated with water. Check for cloudy droplets of ice.

Problem: Does not spray

Solution A) Trigger is too close. Twist the round silver part to adjust the trigger position.

Solution B) The Cry-Ac has been over-filled and there is insufficient air space inside the bottle to create an adequate build up of pressure required to spray. Do not fill past this line.

Solution C) Check that the rubber gasket is in place inside the cover and is not split or missing.

Solution D) The position of the trigger should be directly to the left or right of the delivery tube.

Moisture will damage the cryo paint

This cryo/truck was parked next to the sprinklers and the water must have soaked into the blanket overnight. At the job the next morning, the cryo looked like this. I'm not sure how it's any different from driving through heavy rain on the way to or from a job but for whatever reason, those sprinklers really did a number on the paint job.

I imagine car washes will do the same thing eventually, so if it's not too much of a hassle:

-Leave the cryo at home when you get your truck washed.
-If there's nowhere to put it at home, you can drop the cryo off at the office and pick it up afterwards.
-You could also just leave the cryo on the truck and wash the truck at home, being careful not to get cryo wet.

How to Rough Up Your Discs

Roughing up your discs provides extra grooves for the OCT to cling on to, hopefully preventing the OCT block from falling off when you're cutting sections. There are a few different types of discs that we work with:

Copper discs without holes: This type is excellent at gripping the OCT. Personally, I've never felt the need to rough these discs up, as they do a perfectly good job as they are. They DO, however, take more time to get cold.

Aluminum discs without holes: This type freezes quicker than the copper discs. The circular ridges seem to grip the OCT relatively well, but you might want to rough up the surface for added gripping power, just in case.

Aluminum discs with holes: These are the discs that give techs the most problems. I absolutely recommend roughing these up.



There are two ways to rough up a disc (plus one extra that I'll explain later but won't recommend):

Method #1 - Rub the surface of your disc against cement.  You'll probably find a suitable surface in a parking lot.

Method #2 - Use a screwdriver and your body weight.  This is my favorite method, since you can do it in the office and don't need to remember to do it on the way home. Place your disc ON A CARPETED FLOOR ONLY with your screwdriver at the center of the disc. Lean your body weight into it until the screwdriver slides down to the edge of the disc.  Turn the disc and repeat until you get several grooves radiating out from the center.

Method #3 - Garbage disposal. Obviously, I can't recommend putting your disc through a garbage disposal. I only discovered this method by accident. Ironically, it transformed a problem disc into one of the best discs I've ever worked with. Again, don't do this!

Making Slanted OCT Blocks

Why:  With some cryostats, you NEED to make slanted OCT blocks in order to line up.  (Note that I said “some.”  You never know which cryos require it.  It keeps things exciting.)

If you make a perfectly level block and try to line it up on one of said cryos, you’ll find that it's impossible to close the gap between the top of the block and the blade.  Your options at this point are:

1. Rotate the block upside down. You'll also have to pick up the sections with an upside-down slide so that piece 1 is still on the left side. Or,
2. Melt it down and remake it as a slanted block.

Since you never know which cryos require this, it’s best to just get into the habit of making slanted mounts every single time. 

How:  When sandwiching the tissue between the heat sink and the disc on the cold bar, angle the mounting slide so that the OCT block is thinner on the side closest to the cryostat wall.  It doesn’t need to be steeply slanted, just a subtle slant that you probably won’t be able to see until you take the frozen block off the cold bar.  

Be careful not to make the OCT block so thin on one side that it cuts directly into the disc.  You won’t be able to get any sections from it and you’ll have to melt it down and start over. 

Maximizing Blade Usage - GG

It is possible to use THREE sections of the blade instead of just two. When you slide the blade in, just make sure that it's parallel to the edge of the knife.  The blunt edge of the blade should fit snugly into the groove.  Use your screwdriver to double check the tightness of the top screws, and you'll be good to go!

Disclaimer: I've tested this with three different knives without any problems. I have not, however, tested it with the smaller black-top knives. Just to be safe, take a few practice cuts from the safety layer or from a tissue block that you no longer need before cutting actual slides for the doctor.

A side note: If you make really wide OCT mounts (wider than the metal disc), you probably won't get good results with this method.  All that excess OCT will dull the adjacent section of the blade and you'll only get two sharp areas of the blade before you have to change it out.

Position #1: Insert the blade just far enough to cut the block.
Position #2: Roughly in the middle. You won't be able to see either of the 2 elliptical holes.
Position #3: Move the blade all the way over until just the tail end of the blade is cutting the block.

Safety Update: In Position #3, notice how there's quite a bit of exposed blade on the left-hand side. You run the risk of cutting yourself, since your left hand is the one that's working inside the machine.  I've found that it's safer to take the blade out and flip it over so that the blade looks like Position #1 but with the circular hole on the right side.