29 June, 2008


I think I'm going to begin wearing the maximum amount of PPE we have on the weekends and late nights in the lab to keep security from barging in and demanding to see my ID. PPE = personal protective equipment. I suspect that opening the door to the lab and seeing me working in the biosafety cabinet with a gas mask-style respirator, chemical splash goggles, 3 pairs of different gloves, and one of our big blue plastic suits would deter them from bothering me. Maybe I could use the head lamp with magnifying eyepieces, too.

Of course, now I'm going to have to put all of this on and get someone to take a picture of me in it.

26 June, 2008

Cecum II

It should be noted that, upon reflection, I have seen a bigger cecum than the one noted before, but it was in a mouse infected with cholera, and as such was mostly liquid anyway.


It's like the murine equivalent of an appendix, only with a digestive function and not just as a reservoir for normal gut flora. The jejunum feeds it and the ileum drains it, but it's pretty much a big J-shaped sack that holds digesting food. I do not know what it's contents would look like in a wild mouse with a heterogeneous diet, but in lab animals with a homogeneous diet it is uniformly brown (think pre-poop).

I bring up the cecum because I dissected out possibly the biggest cecum I have ever seen the other day. It was from a Germ-free Swiss Webster mouse, about 18 months of age, who was suffering bloat from a downstream gut twist. Ceca tend to bloat anyway in germ-free mice, and the gut twist may have backed up materials as well (although it pooped on me anyway when I picked it up), but the mouse still had retained ~3g of cecal contents (mouse weighed maybe 25g). That's incredible!

If I had the same relative mass of undigested food in me, that'd be about 9kg!

(I have a morbid tendency to calculate things upward from mice to my own mass. For example, the LD50 of Stx-2 (Shiga-like-toxin-2, produced in very virulent O157:H7 E coli strains) in mice is about 1.3E-5g/kg [if I am remembering the paper on it correctly]. Which means that the LD50 for me would be only about 3mg!).

05 June, 2008