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Dr. Lombardo Palma
Just a comment on the semantics we will face when neuro-protection
becomes widely practiced. I agree that neurons can
not be brought back to life, after death. Nor do we now know how or have
the means to make them replicate.
However, the importance of early recognition and treatment of stroke is
the fact that we now know that non-functioning neurons(during an acute
stroke) are not all dead.
There are two areas in stroked brain tissue. The area of necrosis (dead
cells) is called the "core" of the stroke which most likely
represents the center which has had no blood flow for more than 10
minutes. However, most neurons will be in the low blood flow areas, with
varying degrees of ischemia, called the penumbra.
Neurons from different zones have varying degrees of sensitivity to
ischemia. Nevertheless, they can be "rescued" many hours
or
even days after the onset of the stroke if reperfused (blood flow
restored) and neuroprotected.
Reperfusion can be accomplished with blood clot busters (i.e.: rt-PA).
However, it (reperfusion) in itself is damaging to ischemic
neurons, probably because it increases the production of free radicals,
oxygen radicals for the most part.
Neuroprotection can be accomplished with NMDA blockers, free
radical blockers and scavengers, mild hypothermia or avoidance of
hyperthermia, proper nutrition and by blocking apoptosis (cell
suicide). The rescued cells can become functional again if
protected for a period of days or weeks, after which the
constricted blood vessels adjust to the lack of (blood) tissue perfusion
and compensate with vasodilatation and reperfusion.
It is also helpful if the recovering cells are provided with the essential
nutrients (substrates: citidine and choline) to repair their
damaged cell walls.
Recovering (rescued) cells will need a short period of retraining
(physical, speech or occupational therapy) to become fully
functional. With such a program, we may realize the goal of
returning stroke patents to their previous jobs (functional
status).
Dr. Lombardo Palma LDLPALMA@IHC.COM
(mine uthevelser, Trond)
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