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low uric acid and MS

Dr. Alan Wheatley rawheatley at canadalane.demon.co.uk
Sun Apr 4 15:06:15 EST 1999


In the couse of the discussion of the relatiionship between low serum uric
acid and multiple sclerosis, "p.j.h" <kenneth.grant at worldnet.att.net> 
(7468, Thu, 1 Apr 1999) wrote:

>what is oxidative stress?

Oxidative stress is a term used with varying degrees of precision to refer
to damage sustained by organisms due to the presence of oxidising
substances.  The archetypal oxidant, oxygen itself as O2 molecules, is of
course essential to the survival of higher organisms.  However, some of
the products of mitochondrial respiration are a source of oxidative
stress, as are the products of the activity of such enzymes as
lipoxygenase and xanthine oxidase and of phagocytes, white blood cells
that are part of the immune system.  A wide range of substances derived
from oxygen take part in the damaging reactions.  Most frequently
implicated are the free radicals (molecules having an unpaired electron
and hence usually very reactive) superoxide [.O2]- and hydroxyl [.OH ];
Often involved are hydrogen peroxide (H2O2) and singlet oxygen (high
energy O2).  Other chemical species implicated include hypochlorous acid,
peroxynitrite (discussed in the paper by Hooper et al. that I referred to
in my last posting) and transition metal ions.  The damage inflicted by
the oxidants consists of peroxidation of lipids (which damages cell
membranes) and corresponding damage to proteins and DNA; these effects can
be cytotoxic and are believed to have a role in atherosclerosis (leading
to heart attacks), Alzheimer's disease, rheumatism and other inflammatory
conditions, head injury and strokes, multiple sclerosis, formation of
cataracts, toxic damage by heavy metals and a host of other pathologies. 
Oxidative stress can be detected or measured by assaying a variety of
markers for lipid peroxidation, or by monitoring the depletion of
antioxidants, which protect the organism against oxidative damage.  There
is more information and some links on my website (URL below).

                                                   Alan.

Dr. Alan Wheatley at http://www.canadalane.demon.co.uk



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