This Top Tip comes from Patricia Hugman, Senior Laboratory Technician at St Joseph’s College Toowoomba. Thank you, Patricia! This is something we get asked all the time and the collective wisdom of lab techs is the best source of info.
Have you ever wondered how long it would take to defrost … brains for dissection?
I found the following method for defrosting brains to be very effective & efficient
To defrost brains ‘al dente’ in 1hr
1. Straight from freezer
2. Place brains in packet in suitable container & cover with water (4 litre icecream container works well) sitting ‘flat’ not ‘end on’
1pkt/ container defrosts faster that 2 in one container
3. @20min – Change water
4. @40min – discard water, remove brains from packet, sprinkle liberally with salt, just cover with water
5. @50min – gently separate brains, being careful of brainstem/medulla
6. @60min – carefully remove individual brains, pat dry with paper towel and ‘serve’ to students!
On a nice summer’s day (25deg C) this timing worked a treat. Producing brains that were still firm but not icy.
Sitting on the bench (in air) produced irregular defrosting >4hr
One of my favourite things about conferences is catching up with the other suppliers and checking out all the cool new stuff they have for you. In Cairns in June the lovely lads from Scientrific gave me a sample of the Nalgene Super Versi-Dry Surface Protector with instructions to try it out as a dissection mat and report back.
The mat comes as a sheet or a roll and you can easily cut a piece to the size you need. It’s designed with all sorts of lab tasks in mind, it’s chemical resistant and absorbs spills.
The front of the mat is slightly fuzzy and the back has a waterproof coating to stop ‘yuck’ from soaking through on to the bench. I’m going to test it out on an eye dissection to see how it goes.
The slip resistant surface of the mat held on to the specimen nicely and stopped it from scooting out from under the scalpel blade. Porcine eyes aren’t very big so your fingers are quite close to the blade. The less slippage, the better. Once the eye was opened the mat soaked up the vitreous humour that spills out and usually makes your dissection tray a bit slippery.
I didn’t bother with a dissection board – I just used the mat directly on the table. You can see the back of the mat here hasn’t let any of the moisture leak through and hasn’t been cut by the normal use of the scalpel.
I tested a direct slice with the scalpel onto the mat and it did go straight through but that wouldn’t be a problem during a normal dissection. Pushing the scalpel straight down through the layers of the cornea onto the mat didn’t cut through it at all. You would probably use the mat on top of some sort of dissection board in the classroom anyway to avoid any damage to your benchtops.
At the end of the dissection your boards and benches should just need a quick spray and wipe down with some disinfectant unless someone has really gone to town with the scalpel on the mat. The mat can be cut to size and then the leftovers can be wrapped up in it and disposed of so there is very little wastage and it will help with tidy up at the end of the class.
All in all, I think this would be a valuable addition to the lab. Not only for dissections but for all sorts of experiments in the classroom as well as for jobs in the prep room. Don’t forget it is chemical resistant as well so it can be used to protect your benchtops from chemistry experiment spills and thrills. Next time you see Scientrific at a conference then ask to have a look at a sample.
The Nalgene Super Versi-Dry Surface Protector sample was supplied free of charge on the understanding that it would be honestly reviewed on this site without influencing the outcome of the review.
A drop of Nilodor in the corner of the dissection tray will mask any odour coming from the specimen during the dissection class. Don’t use more than a drop, even though it doesn’t seem like much, because the Nilodor has a scent of it’s own and some people can smell it. One drop will be enough to suppress that smell that lungs sometimes have when you are working with a pluck.
This top tip comes from Kent Bulger, HOD of Science at Sandgate District State High School. The lucky kids at this school, and some Year 7 extension students from nearby schools, have really been getting their pound of flesh out of our specimens this term with a look at just about everything we stock. All reports are that they had a great time and learned a lot.
My top tip for Nilodor is to not bother looking in pharmacies for it – you’ll find it in the supermarket with the drain cleaners.