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[IP] closing the loop

	There's been a lot of posts lately about possible closed loop
systems (artificial pancreas).  Actually, this is still not nearly
possible, even with a continuous glucose monitor.  The major problem that
has not been solved is actually the insulin delivery.  With a subcutaneous
infusion, the quite variable 3-4 hour absorption of even "fast" Humalog, is
much too slow for any possible automated system.  In a normal pancreas,
when BG rises, insulin enters the blood in 3-4 MINUTES, not hours.  If you
let an automatic pancreas bolus for meals, the overshoot in insulin
secretion would likely kill you quickly.  This is not a trivial problem.
So unless one of the companies can devise a faster way to deliver insulin
to the blood, closing the loop will not occur.  [In this regard, there have
been some trials by D to deliver insulin intraperitoneally (which would be
much much faster than subcutaneous), but I don't know how these turned out
or if it could be long term.].  Intravenous delivery would also work, but
leaving a chronic indwelling IV line doesn't seem practical yet, or safe.
	Nevertheless, if any of these new continuous or noninvasive glucose
sensors ever become practical and readily available, it will by itself be
one of the most significant advances in diabetes management since insulin
itself.  I'm more than happy to "close the loop" with my brain and

>> 6  D has developed and received approval in Europe for
>> a closed loop system or artificial pancreas

>MiniMed has been working on such a system for over a year.  Early tests with
>dogs have shown a high level of success.  One person whose son works for a
>medical research organization (I don't know which one) has told me that one
>has been implanted in at least one human being.  Since I haven't been able
>to substantiate this, it's best to consider it a rumor at this point.

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