Random tidbits

Going through my studies, I come across random tidbits of information that seem like they might be nice to share. I’m not talking anything profound; rather, just potentially-useful facts, mnemonics, links, etc.

I’m sure we all come across those with some frequency. I was thinking that it might be nice to compile them somewhere around OPM (that is, this thread) - some sort of random tidbit repository that someone could poke around if they had a moment and wanted to learn something (or at least get some exposure).

Does anyone have any interest in something like this? I’ll start it off with a few examples…

I thought this was a nice animation of a sarcomere contraction.

And of course, to remember the order of lines and bands in a sarcomere, there’s the old mnemonic

Ze Intelligent Animal Has Muscle


Z line / I band / A band / H zone / M line

Going through rheumatology (which we did as part of musculoskeletal), I remember having learned that one should never treat an acute gouty attack with allopurinol, as that will only extend the attack’s duration. Instead, use colchicine, steroids, and/or NSAIDs.

Allopurinol is indicated for prophylactic use in chronic gout.

Elastase breaks down elastin.

a1-antitrypsin acts by inhibiting elastase.

So… if you have a deficiency in a1AT, elastase is NOT inhibited, so it breaks down lots of elastase.

The main pathologic manifestation of this is emphysema.

The link between a1AT and emphysema is a good example of something that probably wouldn’t stick if I just tried to memorize it. Now that I actually understand what’s going on, though, I think it just might.

Some problems with a1AT:

  • a1AT deficiency, which is congenital

  • a1AT is secreted by liver cells; so cirrhosis can mess up its function

  • at least per wikipedia, cigarette smoke might mess up the elastase binding site of a1AT - which is perhaps why smoking leads to emphysema

I just learned this from wikipedia. You have no idea how much confusion knowing this might have saved me

The Latin prefix “myco—” means both fungus and wax; its use in “mycobacteria” relates to the “waxy” compounds that compose parts of the cell wall.

For some clinical relevance:

TB and leprosy are caused by mycobacteria.

There’s also a group of mycobacteria called MAC (mycobacterium avium complex) that hits people with compromised immune systems, especially d/t AIDS. MAC is prevented with prophyllactic use of azithromycin - a MACrolide.

Found this to be a nice quick review of renal tubular physiology (and diuretic effects) :