See friends this provocative release from N.Y. Times :
By JOHN O'NEIL
W hat good is pain? Researchers at the University of
California at
San Francisco think that in the case of an inflamed
joint, that ache
may be the body's way of telling its most aggressive
defenders,
"Enough, already -- you're hurting me!"
Dr. Holly Strausbaugh, a fellow at the N.I.H. Pain Center at
the university,
said that research by her team, published last week in the
journal Nature
Medicine, demonstrated one way pain plays an important role
in regulating
the body's inflammatory cycle.
In that cycle, the body responds to injury or intruders by
releasing an array
of substances that fight infectious agents and speed healing
by increasing
blood flow. Swelling, mild fever and soreness are all signs
that an
inflammatory response has been set off.
If unchecked, these defenses can cause serious harm to
healthy tissue;
that is what happens in chronic inflammatory diseases like
arthritis. But
how the defenders know when to ease up has remained a
mystery.
In 1995, researchers at the university found that the
activation of pain
nerves seemed to serve as a signal to reduce swelling, and
Dr.
Strausbaugh's team hoped to find out more about the
biochemical
mechanisms involved.
They looked specifically at the link between pain and
neutrophils, "little
short-lived cells that pack a real wallop," in Dr.
Strausbaugh's words, and
are the body's first line of defense. Rats given an
electrical impulse
designed to simulate the firing of pain cells were found to
have lower levels
of neutrophils in inflamed joints.
A second phase of the experiment found that the pain signals
dampened
the inflammatory response by inhibiting neutrophils' ability
to release
L-selectin, a substance that allows them to leave the
bloodstream and enter
an infected area.
Dr. Strausbaugh says the new research underscores what a
fine balance is
needed in turning on and off the body's defenses.
"Inflammation is a good thing when everything goes according
to plan," she
said. Part of the plan seems to be that pain cells,
generally activated at the
moment of trauma, subside during the initial stages of
immune response
before reasserting themselves. "It does seem like it takes a
while for pain
to develop," Dr. Strausbaugh said. "It's almost like the
inflammation has to
build up to a certain degree before fibers activate and say,
'That's enough.'
"
Those kinds of questions about timing may prove useful in
improving pain
management, she said.
"Our thinking would be that people with less pain would be
getting more
neutrophils into the site," Dr. Strausbaugh said.
Without the normal initial pain, the body's most aggressive
defenders
responded full force, with a positive result in the short
term; but damage to
healthy tissue seems likely to rise if the mechanisms to
moderate such
all-out assaults are held in check too long.
Dr. Strausbaugh conceded that people will always think of
pain "in a very
negative way." But she speculated that understanding its
purpose could
make it easier to bear. And just as other recent work has
shown that
people with mild fevers might be better off not taking
analgesics to
suppress it, she said, it may be that in a few years doctors
may be telling
patients that a little pain can be good for them.
--
Cheers ,
+----| Joao Paulo de Carvalho |------ +
| [log in to unmask] |
+--------| Salvador-Bahia-Brazil |------+
