Thursday, April 22, 2010

Best urine quotation

“What is man, when you come to think upon him, but a minutely set, ingenious machine for turning with infininite artfulness, the red wine of Shiraz into urine?"

Isak Dineson, Danish author (1885-1962)

I first heard this quotation from my mentor Adrian Katz. Only Adrian would compare the wine you were currently drinking to urine. 

Friday, April 16, 2010

How I used my newly acquired PubMed skills

Yesterday I gave one of my favorite lectures, Renal Adventures in Imaging.

After I finished the lecture I spent some minutes playing with my new skills on PubMed and found this article: N-acetylcysteine effect on serum creatinine and cystatin C levels in CKD patients that completely goes against one of the figures and points of my newly scribed chapter:
[The inability of acetylcysteine to prevent dialysis or mortality] maybe because acetylcysteine alters creatinine handling in the proximal tubule. Acetylcysteine, actually accelerates the excretion of creatinine resulting in decreased serum creatinine.

After Tepel published his original work on acetylcysteine in 2000 everyone went a little crazy drinking the Mucomyst cool-aid. Here was a cheap, safe and already approved, remedy to the pervasive problem of contrast nephropathy. Everyone was so drunk with the excitement that they didn't note that the 85% reduction in contrast nephropathy was not associated with a reduction in the need for acute dialysis or a reduction in patient morbidity and mortality.

In 2004, Hoffmann Et al. published the above quoted article which showed a modest but significant reduction in serum creatinine following ingestion of acetylcysteine. This seemed to me to be the best explanation for why a therapy could prevent an increase in creatinine but not prevent dialysis. (Data on the lack of prevention of dialysis from Miner et al. Am Heart J 2004.)

Apparently the patron saint of contrast nephropathy, Richard Solomon, recently reevaluated this theory and found it lacking. He took 30 patients with GFR < 60 mL/min and given 1,200 mg of acetylcysteine every 12 hours for four doses. Creatinine and cystatin C were measured at baseline, 4 and 48 hours after the last dose of acetylcysteine. They found:
Serum creatinine and cystatin C levels did not change significantly at either 4 h or 48 h following the last dose of NAC compared with the baseline values (Table 2; Figures 1 and 2). However, a small but statistically significant reduction in the ratio of serum creatinine to cystatin C was observed at 4 h but not 48 h.
click to enlarge

Solomon postulates that in patients with chronic kidney disease (a population that better represents the people who actually are given contrast nephropathy prophylaxis) the proximal tubule secretion of creatinine may already be maximized so that it cannot be further upregulated by acetylcysteine.

The end result is that changes in creatinine found during acetylcysteine administration likely represent changes in GFR and are not merely artifactual.

Noon conference St John Macomb: Renal Adventures in Imaging

Yesterday I gave one of my favorite lectures, Renal Adventures in Imaging.

It is a lecture on three issues in nephrology that are not normally put together in a single lecture:

  1. Phosphate nephropathy
  2. Nephrogenic fibrosing dermopathy (I'll never get used to calling it nephrogenic systemic fibrosis because, despite what the literature states, all five patients I have seen had purely dermatologic manifestations)
  3. Contrast nephropathy
I like the lecture because it is not a typical nephrology lecture. 

I gave the lecture Seder-style and had crammed for the last three days getting the booklet ready. It's the longest booklet by one sheet (32 pages rather than my standard 28). It turned out pretty good, though the acetylcysteine section needs to be built up and I need to comb through it for typos.

Thursday, April 15, 2010

Just spent 15 minutes getting better at PubMed

This is time that will pay major dividends down the road.

The mayo clinic libraries have posted a series of screencasts that will make you better at PubMed. Spend the time.

Saturday, April 3, 2010

iPad: the delivery on a 14 year old pledge

In 1996, a year before returning to Apple, Fortune interviewed Steve Jobs. When asked what he would do to save Apple he explained:
If I were running Apple, I would milk the Macintosh for all it's worth — and get busy on the next great thing. The PC wars are over. Done. Microsoft won a long time ago.
At that time, this quote was like a dagger in my heart. At the time Apple was flailing. Windows was rocking and the drumbeat of the end was getting louder. To hear the creator of the Mac declaring the war lost was heart breaking. I chalked it up to an off-the-cuff, spoiled-grape quotation.

Later, after Steve came back to Apple I began to feel vindicated in my opinion. Steve didn't act like he was "milking the Macintosh." In no way could I see his actions as just "milking the Mac." Check out this video of Steve at the 1997 MacWorld. I see no indication of the hopelessness that the PC wars were over (Steve enters at 5:30):

So from the moment Steve re-enters the PC picture, he restokes the PC wars. He introduces the iMac. He successfully recreates the NeXT operating system as OS X. And, though he had phenomenal success growing Apple's computer business, none of that really fits the bill of The Next Insanely Great Thing.

When the iPod came out in late 2001 I wondered if this was the next great thing, but music, no matter how cool, was just too small a stage for the man who had twice revolutionized computers. Also when you look at the history of the iPod it wasn't an Apple idea, rather, the concept was brought to Apple by Steve Fadell after Real passed on it. It didn't feel like what steve meant by "getting busy on the next great thing."

What the iPod did do, is demonstrate that Apple could win in consumer electronics. This time after Apple innovated the followers at Sony, Microsoft and Dell couldn't overtake'em. The disaster which nearly destroyed Apple in the PC wars wasn't re-run during the digital music revolution. Apple invented the digital music business and ten years later the story is still only about Apple.

When the iPhone was introduced this felt like the The Next Big Thing. Phones are ubiquitous and important. The shift to mobile computing has been a long standing theme in the computer industry. Smart Phones aren't just about smarter phones but putting the power of the computer in your pocket. So it was clear that the iPhone fit the bill of the "the next great thing" but what wasn't clear was that it would replace the Macintosh. 

With the introduction of the iPad I am now convinced that it will replace the Mac. The two pieces of data that convinced me of this was the demonstration of the iWork for iPad and the support for real keyboards. Both of those mean that the iPad is not just a media consumption device but also a media creation device. Congratulations Steve, I hope the iPad represents the next revolution in computing.
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