[H] off-topic: re-booting the system
Posted: Mon Oct 08, 2007 2:32 pm
WASHINGTON (AP) -- Some scientists think they have figured out the real job
of the troublesome and seemingly useless appendix: It produces and protects
good germs for your gut. That's the theory from surgeons and immunologists
at Duke University Medical School, published online in a scientific journal
this week.
For generations the appendix has been dismissed as superfluous. Doctors
figured it had no function. Surgeons removed them routinely. People live
fine without them. And when infected the appendix can turn deadly. It gets
inflamed quickly and some people die if it isn't removed in time. Two years
ago, 321,000 Americans were hospitalized with appendicitis, according to the
Centers for Disease Control and Prevention.
The function of the appendix seems related to the massive amount of bacteria
populating the human digestive system, according to the study in the Journal
of Theoretical Biology. There are more bacteria than human cells in the
typical body. Most are good and help digest food. But sometimes the flora of
bacteria in the intestines die or are purged. Diseases such as cholera or
amoebic dysentery would clear the gut of useful bacteria. The appendix's job
is to reboot the digestive system in that case.
The appendix "acts as a good safe house for bacteria," said Duke surgery
professor Bill Parker, a study co-author. Its location _ just below the
normal one-way flow of food and germs in the large intestine in a sort of
gut cul-de-sac -- helps support the theory, he said. Also, the worm-shaped
organ outgrowth acts like a bacteria factory, cultivating the good germs,
Parker said. That use is not needed in a modern industrialized society,
Parker said.
If a person's gut flora dies, it can usually be repopulated easily with
germs they pick up from other people, he said. But before dense populations
in modern times and during epidemics of cholera that affected a whole
region, it wasn't as easy to grow back that bacteria and the appendix came
in handy. In less developed countries, where the appendix may be still
useful, the rate of appendicitis is lower than in the U.S., other studies
have shown, Parker said.
He said the appendix may be another case of an overly hygienic society
triggering an overreaction by the body's immune system. Even though the
appendix seems to have a function, people should still have them removed
when they are inflamed because it could turn deadly, Parker said. About 300
to 400 Americans die of appendicitis each year, according to the CDC.
Five scientists not connected with the research said that the Duke theory
makes sense and raises interesting questions. The idea "seems by far the
most likely" explanation for the function of the appendix, said Brandeis
University biochemistry professor Douglas Theobald. "It makes evolutionary
sense."
The theory led Gary Huffnagle, a University of Michigan internal medicine
and microbiology professor, to wonder about the value of another body part
that is often yanked: "I'll bet eventually we'll find the same sort of thing
with the tonsils."
of the troublesome and seemingly useless appendix: It produces and protects
good germs for your gut. That's the theory from surgeons and immunologists
at Duke University Medical School, published online in a scientific journal
this week.
For generations the appendix has been dismissed as superfluous. Doctors
figured it had no function. Surgeons removed them routinely. People live
fine without them. And when infected the appendix can turn deadly. It gets
inflamed quickly and some people die if it isn't removed in time. Two years
ago, 321,000 Americans were hospitalized with appendicitis, according to the
Centers for Disease Control and Prevention.
The function of the appendix seems related to the massive amount of bacteria
populating the human digestive system, according to the study in the Journal
of Theoretical Biology. There are more bacteria than human cells in the
typical body. Most are good and help digest food. But sometimes the flora of
bacteria in the intestines die or are purged. Diseases such as cholera or
amoebic dysentery would clear the gut of useful bacteria. The appendix's job
is to reboot the digestive system in that case.
The appendix "acts as a good safe house for bacteria," said Duke surgery
professor Bill Parker, a study co-author. Its location _ just below the
normal one-way flow of food and germs in the large intestine in a sort of
gut cul-de-sac -- helps support the theory, he said. Also, the worm-shaped
organ outgrowth acts like a bacteria factory, cultivating the good germs,
Parker said. That use is not needed in a modern industrialized society,
Parker said.
If a person's gut flora dies, it can usually be repopulated easily with
germs they pick up from other people, he said. But before dense populations
in modern times and during epidemics of cholera that affected a whole
region, it wasn't as easy to grow back that bacteria and the appendix came
in handy. In less developed countries, where the appendix may be still
useful, the rate of appendicitis is lower than in the U.S., other studies
have shown, Parker said.
He said the appendix may be another case of an overly hygienic society
triggering an overreaction by the body's immune system. Even though the
appendix seems to have a function, people should still have them removed
when they are inflamed because it could turn deadly, Parker said. About 300
to 400 Americans die of appendicitis each year, according to the CDC.
Five scientists not connected with the research said that the Duke theory
makes sense and raises interesting questions. The idea "seems by far the
most likely" explanation for the function of the appendix, said Brandeis
University biochemistry professor Douglas Theobald. "It makes evolutionary
sense."
The theory led Gary Huffnagle, a University of Michigan internal medicine
and microbiology professor, to wonder about the value of another body part
that is often yanked: "I'll bet eventually we'll find the same sort of thing
with the tonsils."