Saturation Point

It's 9:45 on Friday night. I spent all day studying since we didn't have class. Tomorrow I have my first saturday exam of medical school. They are de rigeur next year, but this is the first so far. The curriculum deans decided to rearrange the schedule such that we have a week off for thanksgiving rather a the cost of having a saturday exam. I am desperately looking forward to a break. I haven't ever had so much consecutive school. 15 weeks straight. This week has been particularly brutal. Yesteray we (Aaron, Dan and I) started reviewing histology slides at school at 630. My study day ended at 10pm, with about 30 minutes off for lunch and some miscellaneous breaks. Today wasn't much better, but at least we started at 8.

I have finally put all the pieces together for the regulation of glycolysis, gluconeogenesis, TCA cycle, oxidative phosphorylation, the pentose shunt, glycogenolysis, glycogen synthesis and some other miscellaneous junk. These processes govern how and when sugar is both broken down and synthesizd. Mostly they follow common theme of phosphorylation inducing activation or inactivation of a particular key enzyme. It's a complex system of switches, where by inactivating one enzyme, you can activate another which deactivates a third, and allows the process to go. The logic of it can be kind of hard to get, but after taking genetics at UO, this makes a lot more sense.


To bring some clinical relevance to this very dry biochem, they bring up obscure metabolic anomalies with defects in these enzymes. For example, Galactosemia illustrates the importance of having a galactose-1 phospho uridyl transferase or a galactose kinase enzyme. Without one of these, an infant cannot process lactose in its mother's milk (lactose is a disaccharide made of galactose and glucose). The infant becomes severely hypoglycemic (CBG of ≈ 10 mg/dl), has seizures, coma, and if the deficiency isn't caught within 3 days, irreparable brain damage. Useful in real life? hmmmm. The pediatrician in the case we studied (this happened at SLU) hadn't ever seen it in 20 years. It has an incidence of 1/62,000. Useful for USMLE step 1, most definitely.

This is what's been on my mind all month, so now it's on yours.

And now I lay me down to sleep
my pile of textbooks at my feet
If I should die before I wake,
that's one less test I'll have to take.