From: ((Steven B. Harris))
Subject: Re: Antioxidents
Date: 17 May 1995
Newsgroups: misc.health.alternative

In <D8pLF7.157@crash.cts.com> twcook@cts.com (Tim Cook) writes:

>[...]
>
>>   Comment: Sorry, but it ain't that simple.  If free radicals caused
>>aging, for instance, there should be lots of experiments in which the
>>aging of mammals is slowed by antioxidants (here we refer to maximum
>>life span prolongation in long lived strains).  There are no convincing,
>>verified (i.e., repeatable) experiments of this type.  I know, because I
>>used to do these experiments for a living.
>>
>>    The free radical theory of aging remains a good theory.  Got that?
>>It's a THEORY.  There is better evidence that free radicals are involved
>>in PART of injury, and in PART with SOME degenerative diseases (as
>>distinct from aging).
>>
>[... other enzyme stuff deleted...]
>
>Steve,
>Would you say that this is no different than what we've always been
>taught that drinking orange juice is helpful in preventing a cold or
>other infections by boosting the immune system?
>In your opinion, are the commercially available antioxidants,
>pycnogenol etc. worth the extra $$$ ?
>
>Tim



The antioxidants for which there is the best evidence for
supplementation are pretty cheap: d-alpha-tocopheryl succinate vitamin
E, vitamin C, beta carotene, selenium.  There you get your best bang for
the buck.  Move too far from there and you begin to move into areas
where you're less likely to be getting much, and paying a lot more.
Pcynogenol, for instance, is an extract "supported" by a lot of
un-duplicated (maybe unduplicatable) French science, and an incredible
amount of market hype.  The closest I know of to this phenomena is with
Echinacia, with the primary literature in German, and for extracts
which are generally not used in this country.  It's impossible to
evaluate any of this until somebody does some good repeat studies in
this hemisphere.  The catch is that there is no money to do such
studies, since drug companies do drug research, and the government gives
grants on the basis of prior success (see drug studies).  It's damned
frustrating.

                                      Steve Harris, M.D.

From: ((Steven B. Harris))
Subject: Re: Antioxidents
Date: 23 May 1995
Newsgroups: misc.health.alternative,sci.life-extension

In <D8ytAx.Iq7@midway.uchicago.edu> bmdelane@ellis.uchicago.edu (Brian
Manning Delaney) writes:

>>Bates:
>>>The common cause of this cellular tissue damage is oxidative stress
>>>called 'free radical pathology'.
>>
>>Harris Comment: Sorry, but it ain't that simple. If free radicals caused
>>aging, for instance, there should be lots of experiments in which the
>>aging of mammals is slowed by antioxidants (here we refer to maximum
>>life span prolongation in long lived strains).
>
>You probably just mispoke, but, for the uninformed, that
>should be "_could_ be lots of experiments..", not
>_should_ be. The bod likes balance 'n all -- free radicals
>are not pure evil, they serve a positive function too. So
>too much exogenous anti-oxidants ~= less enzymatic
>anti-oxidant activity, perhaps. There's a bit of (rather
>indirect, admittedly) experimental evidence for a kind of
>homeostatic mechanism like this, actually -- it appears that
>when superox. rad. levels get really low, SOD activity
>declines. No cause&effect has been shown here, tho'.


Comment: yes, what I should have said is: if antioxidants retarded
aging, there should be a lot of experiments showing that for mammals.
You can construct lots of complicated scenarios where free radicals
cause aging be we cannot do anything about it.  These theories are not
only data-free, they are (if you will think about it) mostly data-proof.
No number of antioxidant failures will ever dislodge them, and they
will always be used as the basis of why you should take this here
antioxidant pill to keep you from aging so fast <g>.

>>There are no convincing, verified (i.e., repeatable) experiments of this
>>type. I know, because I used to do these experiments for a living.
>
>One huge (possible) exception, tho': melatonin. "Possible"
>not because the effect is in question -- it isn't; the
>effect is dramatic, and has been demonstrated repeatedly --
>but because the effect could be endocrinological, as opp'd
>to free rad. scavenging.

Again, these experiments are not done on long lived strains.  At the
Walford lab our mice on mild (10%) restriction (necessary to keep them
from getting hugely fat) have max lifespans of 42 months.  Restrict them
and they go out to 54 months.  The longest lived animals getting
melatonin in the Pierpaoli studies went to less than 33 months.  This is
silly.  To me, it's about like a report of men who lived to be 65 on
some drug, as opposed to 55.  It's a life extending effect, but no way
are you going to convince me it's an antiaging effect.  Any group of
people all dead by 65 are not being well taken care of, period.  Any
group of mice all dead by 33 months are a joke-- I don't care what
they've been eating.  Our mice live to 36 months even when we let them
get fat as pigs and give them no drugs.

                                               Steve Harris, M.D.

From: ((Steven B. Harris))
Subject: Re: Antioxidants
Date: 26 May 1995
Newsgroups: misc.health.alternative

In <003734E4.fc@pop.com> p_iannone@pop.com (Paul Iannone) writes:

>Missing the point as usual, Steve. More obscure nutrients may well be
>worth the money.

And I may well win the lottery.  But I'd be silly to count on it.  And
if the downside were large, I'd be silly to bet on it.


>Perhaps 'we' don't know yet. Fine. Waiting around with fingers up our
>noses waiting for you 'expert' ideologues to admit that the stuff is
>actually good for you is not what anyone reading this is interested in
>doing.

Perhaps they'd be more interested in liver tumors or bladder stones?
I've spent the last 10 years trying to find life extension drugs for
mice, and I've used many of the "hype ones" along the way.  One thing
I've found is that it's amazingly hard to improve on mother nature.
Some harmless sounding things that were all the rage among life
extensionists 15 years ago (ethoxyquin, 2-MEA) turn out to be toxic.
Other promising things like NAC don't do any good at all.  Miracle
"antiaging" substances like CoQ10 extend life span, but only on
average-- they don't do anything about maximum life span.  What works
best by far is reasonable vitamins and caloric restrition.  No
individual vitamins have turned out to be much good at megadoses.  But
also, some aren't harmful. Vitamin E has been tested repeatedly, and
it's harmless in rodents no matter how much you give (in reasonable
ranges).  Studies in people (with the exception of the crazy
unrepeatable stuff in the 1970's) shows the same for E.

>You mention vitamin E. When did it become an acceptable supplement?

There wasn't a single day (although Jane Brody probably thinks there
is), since this is a judgement problem with incomplete knowledge.  But
vitamin E has a hell of lot bigger safety record, and a hell of lot more
evidence for a protective function, than does ascorbyl palmitate, or for
that matter, milkthistle (find me a lifespan study for milkthistle).
You draw the line where you want, but I don't take artificial
antioxidants, and the herbal stuff I take is limited to things that
people have been using in quantity for centuries, over lifetimes (wine,
green tea, bilberry, garlic etc).  I don't know if they do any good, but
I'm reasonably sure they don't do harm.

>sci.med.nutrition you still have plenty of people decrying its
>supplementation as utterly unnecessary. Surprisingly, they use the same
>argument as you: 'we just don't know enough yet.'

They don't like the odds based on what they know.  And they may be
guessing correctly.  It is indeed a crapshoot until we have longterm
human studies, but at the same time it would be wrong to toss all
supplements into one basket, and say that a person who takes one but not
another is a hypocrite.  Or was that not your point?

                                                      Steve Harris, M.D.

From: sbharris@ix.netcom.com(Steven B. Harris)
Newsgroups: sci.life-extension,sci.med
Subject: Re: Antioxidants: It's the Goldilocks Problem
Date: 26 Dec 1999 11:31:24 GMT

In <386349B7.CA8D992A@hotmail.com> Paul Moloney
<paul_moloney@hotmail.com> writes:
>
>Here's something that puzzles me.
>As far as I know, Vitamin C is an
>effective antioxidant, and very cheap.
>Other substances have also been promoted
>for their antioxidant effect, such as
>Q10. However, is there any
>reason to take both Vitamin C _and_
>Q10? That is to say, is it equally
>effective just to take _more_ Vitamin
>C? Or, to paraphrase a beer ad, can
>Q10 reach the parts that other
>antioxidants cannot reach?
>
>P.



   Yes.  Vitamin C is just the end-dump for a lot of free radical
cycles that get free radicals out of fats.  The vitamin C itself can't
do it.  Mostly, that's vitamin E's job.  The real question is how much
antioxidant benefit is there if you take more stuff than (say) 400 IU
mixed natural tocopherols and 500 mg vitamin C every day.  That, I do
not know.  I'm reasonably sure these are not harmful doses, and
probably would do you more good than harm over a lifetime.  But I
cannot even be sure of that, since no studies over the long term have
been done with humans, looking at mortality.  All we have is a few
clues from animal studies and epidemiologic studies, but such things
are dangerous.  They are CLUES, no more.  And the only reason they are
worth taking at all, is because nature gets increasingly bad at
regulating your system for optimal inflamation, the older you get.
It's a matter of bad programming, since nature didn't work very hard to
get the programming right, for after you hit 40 or so.  And also,
because Nature doesn't know about antibiotics, and tends to over-react
to damage from the modern point of view.

   If you're thinking of megadosing beyond levels above, remember
something that been mentioned many times on these groups, and that is
that free radicals are different from each other, and not all are bad
things in all circumstances.  Nitric oxide (NO.), for example, is a
very important molecule in your body, and it has two faces-- one nice,
one not so nice.  Too little, and your vessels clamp down, your blood
pressure rises, your gut suffers lack of oxygen and lets bacteria into
your blood, and your infected tissues never get the white cells they
need to control your infection, and keep it local.  White cells never
come.  You die.  Too much NO, however, and your DNA comes apart, your
cells blow up, your capillaries leak, your systemic blood pressure
bombs out, you go into shock, and you still die.  You'd like something
in between, please.  Some here, some there.  Not so much over there.
There are many nitric oxide synthase enzymes, some constituitive, some
not.  Keep the ecNOS, hold back a little iNOS (except in my gut), and
for Heavens sake, don't activate *all* my bNOS.

   Why the two-edged sword?  The reason is that over time, free
radicals have been so much a part of the damage and inflammation
process, that your body has learned to mimic and even deliberately
produce them, in order to produce inflammation where it is needed.  You
NEED some inflammation to both fight infection, and heal.  The trick is
generally to keep it local.  But all that inflammation is mediated by
oxidation and free radical signalling processes.  So the question is
ever: how much is best?  Not too much, not too little.  And it depends
on the circumstances  Antibiotics on board? Is the local process
getting out of hand?  How much healing do we need, and how fast?  Is
the injury from trauma, or infection, or age-related degeneration?  Is
the patient young or old?  We don't have all the answers, but surely
"stomp out as many free radicals as you can, all the time," is not one
of them.  NF-kB is not there because God hates you and wants you dead.
Nature did not give you COX-2 so you could have arthritis pain.  And
although you'd think so to read some books, superoxide isn't made by
your mitochondria only so you'll have wrinkles when you're 50.

From: sbharris@ix.netcom.com(Steven B. Harris)
Newsgroups: sci.life-extension,sci.med
Subject: Re: Antioxidants: It's the Goldilocks Problem
Date: 27 Dec 1999 12:10:49 GMT

In <3866A754.DD9D7D7D@be-research.ucsd.edu> DS
<dsteiger@be-research.ucsd.edu> writes:
>
>So, what have you concluded is optimal for yourself?


   I take 1 gram of C a day, but mainly because the pills are easier to
swallow than the 500 mg tabs.  I do take 400 IU of "mixed natural
tocopherol E" (about 80% d-alpha), or 400 mg (~50 IU) of gamma
tocopherol, on alternate days, simply because the mix in standard
brands is too heavy on alpha, and doesn't reflect the mix you get in
most diets (and there is a bit of evidence that large amounts of alpha
push your tissue gamma levels down).

   The only other major antioxidant I take in fair amounts is CoQ10,
but I don't know if I'm doing myself good or harm, there, and can't
recommend it in general (I do recommend it for anyone on -statin type
anticholesterol drugs).  This one's a personal experiment, which I
can't really defend.  I'm a bit biased in that I once did a CoQ10
experiment in mice with really huge doses (1 pat per thousand in the
dry diet), and am rather convinced of its low toxicity.  On the other
hand, mice normally make CoQ9, not CoQ10, so this was not the same
thing.  Who knows what the toxicity of a lifetime of CoQ10 supplements
is in humans, who make the stuff?  What would have happened if I'd
given mice huge doses of CoQ9?  Besides me going broke.  I dunno.

From: "Steve Harris" <sbharris@ix.RETICULATEDOBJECTcom.com>
Newsgroups: sci.med.nutrition,sci.med,sci.life-extension
Subject: Another Negative Antioxidant Life Span Study in Rodents
Date: Sun, 10 Mar 2002 20:20:08 -0700
Message-ID: <a6h84i$i63$1@slb4.atl.mindspring.net>

Probably the main impact of antioxidant supplmentation in humans will be in
atherosclerosis prevention, which doesn't apply to rodents.  So this doesn't
mean antioxidant supplementation is necessarily worthless in the average
human. But this and many other studies put a money wrench into the theory
that somehow antioxidants interfere with the basic aging process itself.
There is no really good evidence that they do. At least, not in mammals.



Ann N Y Acad Sci 1998 Nov 20;854:352-60


The effect of long-term dietary supplementation with antioxidants.

Meydani M, Lipman RD, Han SN, Wu D, Beharka A, Martin KR, Bronson R, Cao G,
Smith D, Meydani SN.

JM USDA-Human Nutrition Research Center on Aging at Tufts University,
Boston, Massachusetts, USA. meydani_vbl@hnrc.tufts.edu

The impact of diet and specific food groups on aging and age-associated
degenerative diseases has been widely recognized in recent years. The modern
concept of the free radical theory of aging takes as its basis a shift in
the antioxidant/prooxidant balance that leads to increased oxidative stress,
dysregulation of cellular function, and aging. In the context of this
theory, antioxidants can influence the primary "intrinsic" aging process as
well as several secondary age-associated pathological processes. For the
latter, several epidemiological and clinical studies have revealed potential
roles for dietary antioxidants in the age-associated decline of immune
function and the reduction of risk of morbidity and mortality from cancer
and heart disease. We reported that long-term supplementation with vitamin E
enhances immune function in aged animals and elderly subjects. We have also
found that the beneficial effect of vitamin E in the reduction of risk of
atherosclerosis is, in part, associated with molecular modulation of the
interaction of immune and endothelial cells. Even though the effects of
dietary antioxidants on aging have been mostly observed in relation to
age-associated diseases, the effects cannot be totally separated from those
related to the intrinsic aging process. For modulation of the aging process
by antioxidants, earlier reports have indicated that antioxidant feeding
increased the median life span of mice to some extent. To further delineate
the effect of dietary antioxidants on aging and longevity, middle-aged (18
mo) C57BL/6NIA male mice were fed ad libitum semisynthetic AIN-76 diets
supplemented with different antioxidants (vitamin E, glutathione, melatonin,
and strawberry extract). We found that dietary antioxidants had no effect on
the pathological outcome or on mean and maximum life span of the mice, which
was observed despite the reduced level of lipid peroxidation products,
4-hydroxynonenol, in the liver of animals supplemented with vitamin E and
strawberry extract (1.34 +/- 0.4 and 1.6 +/- 0.5 nmol/g, respectively)
compared to animals fed the control diet (2.35 +/- 1.4 nmol/g). However,
vitamin E-supplemented mice had significantly lower lung viral levels
following influenza infection, a viral challenge associated with oxidative
stress. These and other observations indicate that, at present, the effects
of dietary antioxidants are mainly demonstrated in connection with
age-associated diseases in which oxidative stress appears to be intimately
involved. Further studies are needed to determine the effect of antioxidant
supplementation on longevity in the context of moderate caloric restriction.

Publication Types:
Review
Review, Tutorial

From: "Steve Harris" <sbharris@ix.RETICULATEDOBJECTcom.com>
Newsgroups: sci.med.nutrition,sci.med,sci.life-extension
Subject: Re: Another Negative Antioxidant Life Span Study in Rodents
Date: Thu, 14 Mar 2002 21:44:41 -0700
Message-ID: <a6ruch$6ak$1@nntp9.atl.mindspring.net>

"Peter H. Proctor" <pproctor@neosoft.com> wrote in message
news:F61E23FA9FE4F761.72ECB28368D6D4F5.1B683135900E79C2@lp.airnews.net...
> In article <JW5j8.51$_A1.25227@news1.news.adelphia.net> "Nelson J.
Navarro" <nnavarro@adelphia.net> writes:
> >From: "Nelson J. Navarro" <nnavarro@adelphia.net>
> >Subject: Re: Another Negative Antioxidant Life Span Study in Rodents
> >Date: Mon, 11 Mar 2002 17:36:41 GMT
>
> >That's certainly what we're hoping for.
> >What I find encouraging is the fact that NtBHA seems to be much more
> >effective than PBN in vitro.
>
>          NtBHA connects the Nitrone spin traps such as PBN with the nitroxide
> spin labels such as TEMPO.  The latter are quickly reduced to their
> corresponding hydroxylamine "prodrug" forms in vivo.  The "HA" in NtBHA
> stands for hydroxylamine.
> 
> The hydroxylamine derivative reacts with superoxide to (re)generate the
> nitroxide, which then acts as 1) a spin trap, 2) an SOD, or 3) a
> competitive inhibitor of the reaction between superoxide and nitric
> oxide to produce peroxinitrite ( an important mediator of pathogenesis
> ).
>
> Dr P

COMMENT:

Probably you're going to have to do more explaining than that. For the
audience here: "Spin trap" is generally used to describe PBN-type non-free
radical compounds containing nitrone:

C=N-->O
     C

Here the arrow shows that both electrons in the bond are contributed by the
oxygen, giving the bond a formal charge separation (ie, it's a little bit
weird).

Nitrones are not radicals but react with radicals to eat the extra radical
electron and form the corresponding nitroxide:

C-N-0'
    C

Where ' stands for the "radical" or unpaired electron. These compounds
(TEMPO the example) are stable analogs of nitric oxide:

:N-O' where the nitrogen is bonded to two other things instead of just
sporting an electron pair as I've drawn it for NO'.  Nitroxides, as stable
radicals, have an over-all molecular spin, and are used as spin-labels to
put a free radical on organics (some other bond in the molecule is used for
this, so the NO' stays unchanged), which allows them to be "seen" with
electron spin spectroscopy (ESR).

But now here you say that hydroxylamines

C-N-OH
     C

can lose a proton to superoxide, regenerating the nitoxyl  C2- N-O'   But
you then call that a "spin trap".  Nitroxides, being radicals, can form
spin-adducts with things like superoxide O2'- and in that sense "trap" the
radicals.  And TEMPO has been used as a cerebral resuscitation drug, as has
PBN, so the general sponging of radicals is probably similar with these as
it is in NtBHA. But "spin trap" (not a radical) and "spin label" (a radical)
are used quite differently and not interchangably in the literature, as you
well know (I see your many patents on these things).

SBH

From: "Steve Harris" <sbharris@ix.RETICULATEDOBJECTcom.com>
Newsgroups: sci.med.nutrition,sci.med,sci.life-extension
Subject: Re: Another Negative Antioxidant Life Span Study in Rodents
Date: Fri, 15 Mar 2002 21:08:07 -0700
Message-ID: <a6ugke$nfs$1@slb7.atl.mindspring.net>

"Nelson J. Navarro" <nnavarro@adelphia.net> wrote in message
news:fDvk8.1632$Zr3.697158@news1.news.adelphia.net...
> > COMMENT:
> >
> > But that becomes an endless comment, because the combo of antioxidants
> > used today is never the one that will be in vogue tomorrow.
>
> Well sure it does, but that's because science is progressing.
>
> The computers manufactured five years from now will be better than the
> one I have now; cars will be more sophisticated; anti-diabetic drugs
> will be more effective, etc.; why wouldn't the same be true of newly
> discovered antioxidants?


"Progressing" means progressing from something that works to something that
works better, as with computers. Antioxidants basically don't "work" very
well, if at all in people, and never have (show me the study that they
lengthen life). The belief that they will one day is touching, but I'm
afraid it remains to be proven.


> As evidence mounts that oxidative damage to mitochondria plays a
> significant role in aging, and new compounds are discovered that protect
> mitochondria much more effectively than "Vitamin E", for example, we
> will need to test them before we say they won't work, no?

COMMENT:

Yes. But until then, you have only a theory. And not a very good one. You're
made of more than just mitochondria.

I've given you the counter-theory here before. Free radicals are the signals
used by the body's inflammatory system, which is necessary for
infection-fighting, normal healing, and for fighting some (not all) kinds of
cancer.  Free radicals (including deliberately produced ones like NO.)
aren't just garbage to be expunged in every possible way you can think of,
but rather instead are often important signals, not to be ignored. You can't
just willy-nilly shotgun them, and the system which uses them, out of
existence for long, without expecting to pay a price. Nature didn't give it
all of that complicated radical-producing and radical-sensing machinery to
you, for nothing.

How long can you shotgun the entire free radical signal pathways in your
body, and get away with it?  Perhaps hours, if you're treating some really
bad and inappropriate inflammation, such as reperfusion injury.  Maybe days,
if lucky.  Not months or years, unless you'd like to live in a plastic
bubble. If anybody comes up with something that protects mitochondia from
free radicals they produce, if it is to be used for a life-time it's going
to have to be remarkable for its *specificity*, NOT its generality.

But I see that the dopey spirit of Pearson and Shaw is still alive and well
on at least one newsgroup.

SBH

From: "Steve Harris" <sbharris@ix.RETICULATEDOBJECTcom.com>
Newsgroups: sci.med.nutrition,sci.med,sci.life-extension
Subject: Re: Another Negative Antioxidant Life Span Study in Rodents
Date: Sat, 16 Mar 2002 17:19:30 -0700
Message-ID: <a70nk7$7mi$1@slb6.atl.mindspring.net>

"Peter H. Proctor" <pproctor@neosoft.com> wrote in message
news:FC57E6DDB7145C76.3CBE664A97504B36.6F6317DAF4ED0EC1@lp.airnews.net...
> In article <%qAk8.8079$wB4.3122358442@newssvr21.news.prodigy.com> Dave B
<wired123@pacbell.net> writes:
> >From: Dave B <wired123@pacbell.net>
> >Subject: Re: Another Negative Antioxidant Life Span Study in Rodents
> >Date: Sat, 16 Mar 2002 05:08:11 GMT
>
> >Steve Harris wrote:
>
> >> But I see that the dopey spirit of Pearson and Shaw is still alive and
> >> well on at least one newsgroup.
> >>
> >> SBH
>
> >Dr. Packer, one of the world's leading researchers on antioxidants,
> >apparently feels differently. So do many other scientists who have looked
> >at the same data you have. What up with dat?
>
>      If you poll most free radical researchers,  they generally take
> antioxidants.  And yes,  we all know they are messengers.   See.  e.g.,
> www.redoxsignalling.com .


COMMENT:

Well, they sure as hell don't take PBN or NtBHA.  Or even alpha lipoic acid.
Packer probably does, but the way you tell the pioneer is that he's the guy
with the arrow in his back.  Packer's asking for it, if he keeps at this.

What's up with the difference in how Dr. Packer and I see the world?  There
are many possibilities. One of them is that I've gone farther down the
"cocktail trail" than he has, in some ways, and I've "seen the elephant," as
it were, that lurks at the end of it. Or, if you like, the tigers. I've
given large doses of vitamin E, melatonin, PBN, NOS inhibitors, COX
inhibitors, basically the anti-radical anti-inflammation works, to dogs in
resuscitation trials. This works great on the brain but occasionally I see a
dog get pneumonia, and some of them die from it, with complete lung
consolidation, in as little as 12-24 hours, despite heavy IV antibiotics.
And in a very odd way: no fever, no left-shifted neutrophils, no increased
heart rate, no shock (except at the hypoxic end). The last time I saw
anything like that as a physician was treating leukemic patients with no
neutrophils. These dogs have neutrophils, but they're just not working.
Lookie ma-- an immune system, but it does nothing. Hmm.

Dr. Packer works with rats, presumably kept away from infections. When they
do get infected, I doubt he does careful labs and vital signs in the little
critters. And if he does, he's not a physician, and the funny results don't
set off his warning bells. They do mine.

SBH

From: "Steve Harris" <sbharris@ix.RETICULATEDOBJECTcom.com>
Newsgroups: sci.med.nutrition,sci.med,sci.life-extension
Subject: Re: Another Negative Antioxidant Life Span Study in Rodents
Date: Sat, 16 Mar 2002 14:58:53 -0700
Message-ID: <a70fcj$a9m$1@slb7.atl.mindspring.net>

"Nelson J. Navarro" <nnavarro@adelphia.net> wrote in message news:xjIk8.1889
> If it weren't for that tired old platitude, you'd have nothing to say.


If you do a google search for my handle on the net, you'll find out
immediately how untrue THAT is <g>.


> Ok, my car wouldn't work properly if it weren't for friction, I couldn't
> go anywhere. In fact, the whole world wouldn't "work" properly.
> Accordingly, you can't just wipe out friction, nothing would work
> properly.
> 
> Yet friction is one of the primary factors driving the "aging" of my
> car.
> 
> Obvoiusly, the key to a long mechanical lifetime for important parts of
> my car, is to reduce friction in places like bearings and cylinder
> walls.
> 
> Why would aging be expected to be fundamentally different?


COMMENT

Umm, because you're not a car? But let's be general: you've just postulated
a wear and tear model, but even if that's what we're seeing in biology, what
makes you think that free radicals are the major source of biological wear
and tear, not to mention the failure of cells to divide to fix it? Nevermind
that antioxidants aren't going to keep your teeth from wearing out--- what
makes you think that they'll keep any adult organ from wearing out? You're
built from all kinds of one-shot devices besides your teeth (alveoli,
glomeruli, neurons) that there's no mechanism for perfectly replacing any of
them as an adult, when you lose one for any reason. Even if you cut yourself
you're left with a scar.  It doesn't matter how many antioxidants you take,
you're still left with a scar at some level. It's never perfect. You're not
a perfectly self-repairing device, and that's not because you don't take
enough vitamin E.

Let's take another example: the Hayflick limit.  Non-transformed
non-germline cells have a limit on how many times they can divide. This
almost certainly isn't due to oxidative damage, because a dozen experiments
have tried to fix it by dumping antioxidants on cells in dishes, and that
simply hasn't ever worked. To imagine it will work some day with some
antioxidant we haven't found yet, is an article of faith.  It's nice, but
it's not science.

The older you get, the less well your cells make protein, divide, repair
themselves and the ground substance between them, and so on. And many
structures you're made of (neurons, muscles cells) can't divide anyway. The
one thing we know about aging is that agelessness, wherever we've definitely
observed it, requires cell division.  But guess what?  You probably lost the
chance to be entirely subject to reparative cell division when you grew
yourself a brain and filled it with synapse-associated memories.

Now, why do all these age-associated "defects" happen to older cells
(failure to divide, failure to repair without division)?   I frame no single
hypotheses.  I suspect the reasons are manifold. If they were simple and
easily fixed, I suspect Mother Nature would have done that for some complex
animals (ie, those with brains). We have no good reason to think She ever
has.  All candidates for ageless animals are in hyperborean wild places
where there's good reason for skepticism. Can you say Shangri La?

Is it better to have one unifying hypothesis which is unproven, and which
has evidence against it (the non-oxidative Hayflick limit), rather than not
having a unifying hypothesis?  Yes, I think so.  It's more honest to say you
don't know, when you don't know. You can think of me as as taking the
"strong agnostic" position on the cause(s) of aging.  That means I don't
know, but I don't think you do, either.

SBH

From: "Steve Harris" <sbharris@ix.RETICULATEDOBJECTcom.com>
Newsgroups: sci.life-extension,sci.med
Subject: Re: Nitric Oxide Delays Endothelial Cell Senescence
Date: Sat, 16 Mar 2002 17:42:47 -0700
Message-ID: <a70ovs$2kj$1@nntp9.atl.mindspring.net>

"Peter H. Proctor" <pproctor@neosoft.com> wrote in message
news:915882AF8E3E6E0F.DBA265899872B80C.7731E823D9060324@lp.airnews.net...
> >Great. Now in context of our previous discussion, you get to explain to
> >use why, in pursuit of anti-aging, we want to gobble scavengers of of
> >the free radical nitric oxide?
>
>        Because too much NO produced in the presence of superoxide makes
> peroxinitrite, very nasty stuff indeed.  It is the difference between
> cNOS ( which makes low levels of NO as a messenger ) and iNOS, which
> makes high levels as part of the inflammatory/immune response.


Oh, I see. And the NO produced by cNOS
does't produced peroxynitrite?  Or just that you saying that you only want
to sop up the extra NO produced by iNOS when it's activated in inflammation?
What for?  You think it's not doing anything important? How do you know what
the inflammation's doing?  This is an antiaging pill we're talking about,
not something given by the doctor for specific inflammatory problems, after
infection is ruled out, or antibiotics are on board.

Remember, we're not talking about Joe Dokes in the ICU going hypotensive
from septic shock. His iNOS may INDEED be overreacting. Rather, we're
talking Joe Shmoe who is going to take a pill when he's perfectly well, to
slow his aging process. Is this stuff going to interfere with iNOS
activation or NO generation, or not? You can't have it both ways.

>        Turns out low level production of NO by cNOS inhibits high level
> production by iNOS,  as well as (maybe) coproduction of superoxide.   So a
> little NO keeps things operating normally.

So?  Again, nature didn't give you iNOS for nothing.

>  BTW, the action of stable nitroxe radicals such as TEMPO is as
>  competitive inhibitors of the reaction between NO and supreoxide.  Same
>  with their hydroxylamine derivatives.


These things sop up superoxide.  Which your neutrophils are using to kill
bacteria, hey.  You're not thinking this through. If the guy's in the ICU
with septic shock on antibiotics, you may want to dial down his immune
system. If he's just some guy who's trying not to age, and you give him a
pill which is more likely to turn his bronchitis into pneumonia because his
neutrophils don't work, what have you done?

SBH

From: "Steve Harris" <sbharris@ix.RETICULATEDOBJECTcom.com>
Newsgroups: sci.life-extension,sci.med
Subject: Re: Nitric Oxide Delays Endothelial Cell Senescence
Date: Sat, 16 Mar 2002 23:38:04 -0700
Message-ID: <a71dqa$lin$1@slb0.atl.mindspring.net>

"Peter H. Proctor" <pproctor@neosoft.com> wrote in message
news:ECE2276737F7C77E.7986809183FA96F8.43C0CBEEF071D0C1@lp.airnews.net...
> >Or just that you saying that you only want to sop up the extra NO
> >produced by iNOS when it's activated in inflammation?
>
> Sometimes you want to do exactly this, e.g., in a stroke or a heart
> attack.


Yep. And sometimes you don't. That's the problem.

> Sometimes it does, but sometimes it is just doing tissue damage.  The
> system is not very intelligent and can't tell the difference.

Right. So a free radical absorbing antiaging pill may do the right job one
day, the wrong one the next.


> >How do you know what the inflammation's doing?  This is an antiaging
> >pill we're talking about, not something given by the doctor for
> >specific inflammatory problems, after infection is ruled out, or
> >antibiotics are on board.
>
> There is some evidence that a chronic inflammatory process is going on
> as we age.

Sure enough.  But also, a number of other immune systems weaken, especially
lymphocyte activation, which eventually shows up as age-related declines in
both bacterial and viral defences. If it was a matter of just dialing the
whole system down, or cutting the activity of neutrophils (end effectors in
defense against bacteria and fungi) down, we'd do that.  But it's not safe.


> >Remember, we're not talking about Joe Dokes in the ICU going
> >hypothesize from septic shock. His iNOS may INDEED be overreacting.
> >Rather, we're talking Joe Shmoe who is going to take a pill when he's
> >perfectly well, to slow his aging process. Is this stuff going to
> >interfere with iNOS activation or NO generation, or not? You can't have
> >it both ways.
>
> I'll take the chance.  And this is far from the only thing that is going
> on.


Well, you can be my guest about taking the chance. The problem is, that a
lot people are going to be taking the "chance" without knowing what they're
doing.


>           Antimicrobial defense,  mainly.  But it gets turned on at other
> times when you definitely don't want it.    E.g. Stroke and heart attack.


Yes. So save the fancy free-radical inhibitors for when you get the stroke
or heart attack. Let the paramedics give them. You will complain that that
may be non-optimal, but that's not an argument for a pre-treatment which is
itself dangerous from other grounds.  As well suggest on the same grounds
that everyone inject themselves every day with TPA BEFORE the stroke or
heart attack. That would work better on stroke or heat attack, but it's the
side effects that are the problem.



>          I view this the same way I do anticoagulation with aspirin. When
> you are out hunting sabertooths, it is important to have your platelets
> operating optimally.  But, if a middle-aged male in modern "safe"
> societies, maybe you don't.

Perhaps (that's an argument I've used myself). But alas, although there's
lot of evidence that the coag system is overtuned for middle-aged people
(they do indeed clot more than they bleed, even on aspirin), there's not the
same kind of evidence that bacterial defenses are.  Infections are an
important source of mortality in the elderly. Most elderly can afford to
lose some clotting capacity. But not neutrophil function.


> >These things sop up superoxide.  Which your neutrophils are using to kill
> >bacteria, hey.  You're not thinking this through.
>
> Actually, I've been thinking this thru for over 30 years <G> But what
> ever...
>
> >If the guy's in the ICU
> >with septic shock on antibiotics, you may want to dial down his immune
> >system. If he's just some guy who's trying not to age, and you give him
> >a pill which is more likely to turn his bronchitis into pneumonia
> >because his neutrophils don't work, what have you done?
>
>         Interestingly,   SOD as a drug doesn't seem to affect antimicrobial
> defense much if any.

Why would you expect it to?  SOD is a protein, and is not going to get into
cells well, much less into the vacuoles of a neutrophil.

>  For one thing,  this function of superoxide, etc. seems
> to be pretty compartmentalized.

Indeed it does.  And so is SOD.  Alas, any free-absorber or spin trap that
gets into cells or mitochondia well (think PBN) will NOT be so
compartmentalized.

> For another,  the product of SOD peroxide
> gets converted to hyochlorite,  which is another antimicrobial agent.

That's hardly a point for your side either way. If peroxide from SOD is
important to myeloperoxidase, then inhibiting superoxide would not be good.
To the extent that neutrophils generate peroxide from non-SOD mechanisms in
the respiratory burst, it doesn't matter one way or the other.

In any case, there is evidence that PBN protects neutrophils from their own
toxic radicals. That's not good news, because they are designed to be
suicide machines: if nature could get more bacterial killing out of her
neutrophils by protecting them with more antioxidants, or cutting down their
radical producing activity, she'd certainly have done so. Why not?

Free Radic Res 1995 Jul;23(1):73-80 Related Articles, Books, LinkOut


Can spin trapping compounds like PBN protect against self-inflicted damage
in polymorphonuclear leukocytes?

Seawright L, Tanigawa M, Tanigawa T, Kotake Y, Janzen EG.

National Biomedical Center for Spin Trapping and Free Radicals, Oklahoma
Medical Research Foundation, Oklahoma City 73104, USA.

Polymorphonuclear leukocytes (PMNs) have been suggested to be damaged by
superoxide radical generated on their own. The protective capacity of a spin
trapping compound, phenyl-N-tert-butyl nitrone (PBN) was evaluated for this
damage which occurs after the induction of superoxide generation. The life
span of PMNs after superoxide generation was measured in the presence of PBN
using the cell counting method, and effects of PBN on the amount of
superoxide generated were quantitated using both cytochrome c reduction and
spin trapping with DMPO. Results indicated significant extension of life
span when PBN was present, and the extension was dose dependent. However,
the magnitude of life span extension was not as large as expected from the
decrease of superoxide generation. Possible mechanisms for the protection of
PMNs by PBN are discussed.

PMID: 7647921 [PubMed - indexed for MEDLINE]

From: "Steve Harris" <sbharris@ix.RETICULATEDOBJECTcom.com>
Newsgroups: sci.med.nutrition
Subject: Re: Another Negative Antioxidant Life Span Study in Rodents
Date: Sat, 16 Mar 2002 22:57:37 -0700
Message-ID: <a71bgk$1us$1@slb6.atl.mindspring.net>

"Dave B" <wired123@pacbell.net> wrote in message
news:pDSk8.8701$3W5.3422780616@newssvr21.news.prodigy.com...
> >>      If you poll most free radical researchers,  they generally take
> >> antioxidants.  And yes,  we all know they are messengers.   See.  e.g.,
> >> www.redoxsignalling.com .
> >
> >
> > COMMENT:
> >
> > Well, they sure as hell don't take PBN or NtBHA.  Or even alpha lipoic
> > acid. Packer probably does, but the way you tell the pioneer is that
> > he's the guy with the arrow in his back.  Packer's asking for it, if
> > he keeps at this.
>
> He IS 70 years and still working full-time.

Comment:

Well, fine that that's nothing special.  He probably takes carnosine and
alpha lipoic acid, but not for 70 years. Whether he takes PBN or not, I have
no idea.  I'm willing to wait. I have the feeling we'll see a lot of
infectious deaths in these life extenders, and a lot of comments of the sort
that "Gee, he looked great and would have lived to be 100, but for happening
unluckily to die of pneumonia (or whatever)."  And let me know when Packer
has tested his cocktails on rodents with the flu or garden-variety
pneumococcal pneumonia.

> Maybe those dogs crossed over to the other side and went toward the light
> instead of back to your lab. If you want to move your research to humans
> I'll volunteer. That'd be a trip. Ever seen Flatliners? ;-)


Yes, and you don't want to volunteer, as humans that lose a lot of neurons
to post anoxic encephalopathy end up Democrats. It's horrible.  Let them go
without oxygen for even longer, and they end up sounding like John Gohde.
And yes, the experiments are very much like in Flatliners, except the dogs
go as long as 15 minutes before being zapped back. They have a long rehab,
but eventually recover. We're eventually going to try for 20.


> Seriously, how is taking antioxidant supplements any different from eating
> alot of fruits/veggies with a high ORAC value? Besides the lack of all that
> sugar.

We don't know how much of the blueberry polyphenols or whatever you absorb
when you eat them.  Also, this is being done with some pretty artificial
radical-traps that are much stronger than anything you see in nature (I
don't know of any natural nitrones in food).

> Were the doses used anywhere near comparable to that of the average
> life-extender?

No, they were much larger than anything anybody's likely to be taking. But
who knows what Durk and Sandy are up to, now? And who knows what chemicals
people having daring, lately? It's a good bet that you body's adapted fairly
well to keep you from having any radical-traps you eat in food suppress your
"pro-oxidative" defenses to the point that your neutrophils are impotent
against bacteria. But when you start shoveling in things like PBN, all bets
are off.

> On a separate note: Isn't it likely that taking the right antioxidants
> would help protect human DNA from radical-induced damage and subsequent
> mutations?

Maybe. It's not impossible that chemicals great for your DNA might push you
over the line on bacteria-fighting.  The people of the future might have
fairly short-acting antiaging pills which they all go though drills on how
to use, including stopping them immediately for fever or any sign of
infection. Sort of like the Malthusian Drill in _Brave New World_. The
future will be (I'm sure) a weird place, and who knows what people will do
there? (Did you think 10 years ago you'd have be using a cell phone like you
do?). I'm merely pointing out that powerful medicines generally take a lot
of thought and practice to use correctly. If there is a good anti-free
radical cocktail in the future, it's not likely that it's going to be the
sort of thing that you can just pop and forget every evening, as you do your
vitamin E. "Life extenders" have been spoiled there, as they would have been
using homeopathy. Coming up are drugs that won't be as benign as vitamins.
They will really free-radical reduction to the limit, and they'll have side
effects, as with steroids, that will be spectacular.

SBH

From: "Steve Harris" <sbharris@ix.RETICULATEDOBJECTcom.com>
Newsgroups: sci.med.nutrition,sci.med,sci.life-extension
Subject: Re: Another Negative Antioxidant Life Span Study in Rodents
Date: Sun, 17 Mar 2002 13:29:49 -0700
Message-ID: <a72ui4$f1k$1@nntp9.atl.mindspring.net>

"Nelson J. Navarro" <nnavarro@adelphia.net> wrote in message
news:%m2l8.3636$Zr3.1285918@news1.news.adelphia.net...
> Well, lots of people here take ALA, some in rather high dosages, with no
> ill effects, as far as I know.

Yeah, but how would you?  Unless it kills them like flies, you'd miss it.

> > Okay, Bub, let's see your evidence.  I want it interventional, not
> > "epidemiologic" (associational).  You don't get to claim that
> > cigarettes cause lung cancer unless you can do a study showing that
> > getting people to quit cuts their lung cancer risk. You don't get to
> > claim that LDL blood cholesterol contributes to atherosclerosis unless
> > you can prospectively change cholesterol in animals or people and show
> > that this has an impact on the disease.
> > 
> > So, where are these experiments in which replicative senescence of
> > cells has been significantly altered or eradicated by changing
> > oxidative stress?
>
> Z Gerontol Geriatr 1999 Apr;32(2):69-75 Related Articles, Books, LinkOut
>
> [Replicative senescence as a model of aging: the role of oxidative stress
> and telomere shortening--an overview]
>
> [Article in German]
>
> Saretzki G, von Zglinicki T.
>
> Institut fur Pathologie, Humboldt-Universitat zu Berlin.
>
> Replicative senescence is characterized by the irreversible loss of
> division potential of cultivated human and animal cells. Correlations
> between the replicative potential in vitro and the age of the donor or
> the maximal lifespan of the species suggest replicative senescence to be
> an appropriate model for aging. Telomeres of human somatic cells shorten
> with each cell division but are stabilized at constant length in tumors
> and immortal cells by the enzyme telomerase. The assumption of a causal
> role of telomere shortening for the limited lifespan of cells in vitro
> was borne out recently. We could demonstrate oxidative stress as a main
> reason for telomere shortening. Telomeres are sensors for oxidative
> damage in the genome. Telomeres shorten during in vivo aging as well;
> however, there are significant differences between individuals. Telomere
> erosion might play a major role for the aging of the immune system. Our
> data suggest that telomere shortening in vivo could reflect the
> cumulative amount of oxidative damage to the organism. It might be
> useful as a biomarker of aging.
>
> PMID: 10408009 [PubMed - indexed for MEDLINE]


COMMENT: Sorry, but we need to see the work which backs this claim (this guy
is reviewing his own work-- never the greatest objectivity when that
happens). So long as we're quoting reviews, see the one at the end of this
message. Cell lines with defects in antioxidant defences do not obviously
have accelerated senescence in culture (which is remarkable).


> Life Sci 1998;63(11):935-48 Related Articles, Books, LinkOut
>
> Age-dependent telomere shortening is slowed down by enrichment of
> intracellular vitamin C via suppression of oxidative stress.
>
> Furumoto K, Inoue E, Nagao N, Hiyama E, Miwa N.
>
> Department of Cell Biochemistry, Hiroshima Prefectural University School
> of BioSciences, Shobara, Japan.


Different guys. And we'd like to see the actual delayed senescence, please.



> J Biol Chem 2000 Mar 10;275(10):6741-8 Related Articles, Books, LinkOut
>
> N-t-butyl hydroxylamine, a hydrolysis product of alpha-phenyl-N-t-butyl
> nitrone, is more potent in delaying senescence in human lung fibroblasts.
>
> Atamna H, Paler-Martinez A, Ames BN.
>
> Division of Biochemistry and Molecular Biology, Department of Molecular
> and Cell Biology, University of California, Berkeley, California
> 94720-3202, USA.
> 
> Alpha-phenyl-N-t-butyl nitrone (PBN), a spin trap, scavenges hydroxyl
> radicals, protects tissues from oxidative injury, and delays senescence
> of both normal human lung fibroblasts (IMR90) and senescence-accelerated
> mice. N-t-butyl hydroxylamine and benzaldehyde are the breakdown
> products of PBN. N-t-Butyl hydroxylamine delays senescence of IMR90
> cells at concentrations as low as 10 microM compared with 200 microM PBN
> to produce a similar effect, suggesting that N-t-butyl hydroxylamine is
> the active form of PBN. N-Benzyl hydroxylamine and N-methyl
> hydroxylamine compounds unrelated to PBN were also effective in delaying
> senescence, suggesting the active functional group is the
> N-hydroxylamine. All the N-hydroxylamines tested significantly decreased
> the endogenous production of oxidants, as measured by the oxidation of
> 2', 7'-dichlorodihydrofluorescin and the increase in the GSH/GSSG ratio.
> The acceleration of senescence induced by hydrogen peroxide is reversed
> by the N-hydroxylamines. DNA damage, as determined by the level of
> apurinic/apyrimidinic sites, also decreased significantly following
> treatment with N-hydroxylamines. The N-hydroxylamines appear to be
> effective through mitochondria; they delay age-dependent changes in
> mitochondria as measured by accumulation of rhodamine-123, they prevent
> reduction of cytochrome C(FeIII) by superoxide radical, and they reverse
> an age-dependent decay of mitochondrial aconitase, suggesting they react
> with the superoxide radical.
>
> PMID: 10702229 [PubMed - indexed for MEDLINE]


This is the kind of thing I asked for.  It still has problems:

1) The effect is modest, and of the same order as the negative effect of
culturing cells at room pO2 tensions, which are 10 times what they're used
to, and made for. This is known to shorten their replicative life (as Ames'
group showed, and others have shown before him), but fixing poisoning is not
the same as delaying aging. Ames knows this. He's forgotten to do the
obvious test, which is antioxidants at physiologic pO2 tensions.

2) Authors don't show this is a generic antioxidant effect. NtPBN is
presumably similar to plain vanilla hydroxylamine in being an .NO prodrug.
We know .NO is progrowth and anti-senescent in epithelia. How about
fibroblasts? Incidentally, I stood up in the audience at a geriatrics
conference in Washington more than 10 years ago and suggested that since PBN
is a prodrug for .NO, that may mediate some of its effects on circulation in
the brain. Richard Cutler was in the audience. The idea has received some
support since. PBN is a prodrug for NtBHA.

> Have you seen the following? Unlike the PPAR gamma agonist rosiglitazone,
> which, if I recall correctly has little or no effect on HDLc, this stuff
> boosted HDLc by 80%.
>
>  Proc Natl Acad Sci U S A 2001 Apr 24;98(9):5306-11
>  A selective peroxisome proliferator-activated receptor delta agonist
> promotes reverse cholesterol transport.


Interesting!  We need something better than niacin.  Hopefully this will
lead to a new class of drug treatment.

Here's the Ames paper on physiologic pO2 culture:

Proc Natl Acad Sci U S A 1995 May 9;92(10):4337-41
Oxidative DNA damage and senescence of human diploid fibroblast cells.
Chen Q, Fischer A, Reagan JD, Yan LJ, Ames BN.

Division of Biochemistry and Molecular Biology, University of California,
Berkeley 94720, USA.

Human diploid fibroblast cells cease growth in culture after a finite number
of population doublings. To address the cause of growth cessation in
senescent IMR-90 human fibroblast cells, we determined the level of
oxidative DNA damage by using 8-oxoguanine excised from DNA and
8-oxo-2'-deoxyguanosine in DNA as markers. Senescent cells excise from DNA
four times more 8-oxoguanine per day than do early-passage young cells. The
steady-state level of 8-oxo-2'-deoxyguanosine in DNA is approximately 35%
higher in senescent cells than in young cells. Measurement of protein
carbonyls shows that senescent cells did not appear to have elevated protein
oxidation. To reduce the level of oxidative damage, we cultured cells under
a more physiological O2 concentration (3%) and compared the replicative life
span to the cells cultured at the O2 concentration of air (20%). We found
that cells grown under 3% O2 achieved 50% more population doublings during
their lifetime. Such an extension of life span resulted from the delayed
onset of senescence and elevation of growth rate and saturation density of
cells at all passages. The spin-trapping agent alpha-phenyl-t-butyl nitrone
(PBN), which can act as an antioxidant, also effectively delayed senescence
and rejuvenated near senescent cells. The effect is dose-dependent and is
most pronounced for cells at the stage just before entry into senescence.
Our data support the hypothesis that oxidative DNA damage contributes to
replicative cessation in human diploid fibroblast cells.

PMID: 7753808 [PubMed - indexed for MEDLINE]

----------------------------------------------------------------------------
----

Here's the mostly negative review on cell culture, senescence, and
oxidation.


Mutat Res 1991 Mar-Nov;256(2-6):177-89
Oxidants and antioxidants in proliferative senescence.
Poot M.

Department of Human Genetics, University of Wurzburg, Germany.

In terms of the amount of experimental research it has generated the free
radical theory of ageing is one of the most popular hypotheses to explain
this ubiquitous phenomenon. From the theory two postulates were derived:
either cellular defence mechanisms against free radical-dependent oxidants
deteriorate during ageing of cells, or essential, unrepairable damages are
imparted to the cell by oxidants regardless of the activity of antioxidant
defence systems. The many reports dealing with a putative breakdown in
antioxidant defence systems failed to positively support this postulate.
However, a minor depletion in cellular glutathione by exposure to a model
lipophilic peroxide led to a significant decrement in DNA and protein
synthesis. In other words, the glutathione redox cycle is intrinsically
fallible with respect to defending the cellular DNA replication system
against this model lipophilic peroxide. Interestingly, after ageing in
culture cells a partial uncoupling of the NADPH-producing and -consuming
systems tends to take place. Experiments involving the addition of
antioxidants to the culture medium have failed to significantly extend the
lifespan of cultured diploid somatic cells. The level of antioxidants
appears to be a modulator rather than a primary determinant of cellular
ageing in culture. Several lines of evidence suggest that DNA damages
accumulate during ageing of the organism, but no oxidant-related DNA damage
has been pinpointed in the cultured cell system. Human mutants with defects
in antioxidant enzymes have not shown conclusive signs of accelerated
ageing. Cells from patients with Werner's syndrome (progeria of the adult),
on the other hand, do not suffer from a defect in their antioxidant defence
system, nor do they accumulate more than normal amounts of autofluorescent
products resulting from lipid peroxidation. The recent finding that Werner's
syndrome constitutes a mutator phenotype may prompt the comparison of
oxidant- and ageing-related mutation spectra in order to investigate a
mutational theory of ageing as a new derivative from the free radical
hypothesis.


PMID: 1722009 [PubMed - indexed for MEDLINE]

From: "Steve Harris" <sbharris@ix.RETICULATEDOBJECTcom.com>
Newsgroups: sci.med.nutrition,sci.med,sci.life-extension
Subject: Re: Another Negative Antioxidant Life Span Study in Rodents
Date: Tue, 19 Mar 2002 09:40:53 -0800
Message-ID: <a77t50$rmd$1@slb0.atl.mindspring.net>

Dave wrote in message <3C96EACC.6090202@nospam.com>...

>Are there any endogenous free radicals that actually behave as
>*anti-oxidants*?  I ask because when you mentioned NO, I immediately
>began thinking of TEMPO, a "stable free radical" and spin label.  Of
>course, TEMPO is synthetically produced, but that may me wonder about
>the possibility of endogenous radicals behaving as anti-oxidants.
>
>Dave


Now you're thinking.  Dr. Proctor has mentioned melanin, which is not only
in skin, but probably in the substantia nigra in the brain in part to
suppress free-radical production there which is a side effect of dopamine
metabolism (and without which, the radicals may destroy things and you get
Parkinson's disease).

Nitric oxide (.NO) itself might act as a radical-adduct trap in places where
there's no .O2- (superoxide), which might be a lot of places in your body.
The .NO does indeed trap the radical superoxide, but the resulting
non-radical peroxynitrite (OONO-) is a powerful oxidant, and even nastier
than if it was a free radical.

--
I welcome email from any being clever enough to fix my address. It's open
book.  A prize to the first spambot that passes my Turing test.