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Posted by Dad on August 03, 2000 at 21:05:29:

>From: FEAT
>Reply-To: feat@FEAT.org
>To: FEATNEWS@LIST.FEAT.ORG
>Subject: Autism Study on Family Struggles/ How Lead Changes,
>Impairs Brain, Learning
>Date: Thu, 24 Aug 2000 15:12:39 -0700
>
>FEAT DAILY NEWSLETTER Sacramento, California
http://www.feat.org
> "Healing Autism: No Finer a Cause on the Planet"
>_____________________________________________________
>NEWS EDITOR: FEAT@feat.org NEWS SEARCH:
>http://www.feat.org/search/news.asp
>LETTERS: FEATBack@egroups.com DIALOGS: FEATBack-subscribe@egroups.com
>August 3, 2000
>
>>* * *
>
>How Lead Changes Brain to Impair Learning, Memory
>
>
http://www.usnewswire.com/topnews/Current_Releases/0803-112.html
>
> U.S. Newswire -- Scientists at the Johns Hopkins School of
Public
>Health have identified a molecular mechanism whereby lead poisoning
>cripples
>learning and memory. Many studies have shown that lead poisoning
impairs
>learning and memory, but this is the first to pinpoint a particular
part of
>the nervous system that is significantly altered in the brains of
>lead-poisoned animals. The researchers also discovered that blood-lead
>levels did not accurately reflect lead concentrations in the brain.
The
>study appears in the August 2000 issue of Neuroscience.
> Senior author Tomas R. Guilarte, PhD, professor, Environmental
>Health
>Sciences, Johns Hopkins School of Public Health, said, "It has been
known
>for some time that lead is a potent inhibitor of the NMDA receptor, a
>protein known to play an important role in brain development and
cognition.
>In this study we demonstrate that lead exposure decreased the amount
of
>NMDA
>receptor gene and protein in a part of the brain called the
hippocampus.
>This change is associated with impairments of nerve communication in
the
>brain and of learning."
> The experiments marked the first time researchers have looked
into
>multiple facets of lead poisoning in a single study: First, the toxic
>metal's effects on learning behavior; second, how it affects the
>communication between neurons; and third, which genes and proteins
crucial
>to nervous system development are adversely affected by lead. Since
all
>pups
>born into the same litter have virtually identical genetic make-ups,
the
>researchers were careful to study these three parameters in rats from
>multiple litters, to make sure that any detected abnormalities were
due to
>lead and not to some genetic anomaly found within one family.
> Rats were given either 0, 750, or 1500 parts per million (ppm)
of
>lead
>acetate through their diet, which made their blood-lead levels
comparable
>to
>those detected in lead-poisoned children in the United States. The
study
>was
>three-pronged, with lead-poisoned and control animals randomly
assigned to
>one of three experiments. To study the effect of lead on learning and
>memory, the first group of animals were taught to find the location of
a
>hidden platform submerged in a pool of opaque water. In this water
maze
>study, the lead-poisoned animals were significantly slower to find the
>platform than controls, indicating that their learning of the new
skill was
>poor.
> Litter mates to these animals were used in studies measuring
how
>responsive particular groups of cells in the brain are to stimuli.
Since
>the
>synapses between neurons are thought to be strengthened during the
process
>of learning, the researchers measured how well a group of neurons in
the
>hippocampus could communicate to form a neural pathway. This set of
>experiments, carried out by Nancy L. Desmond, PhD, assistant
professor,
>Neurosurgery, University of Virginia, Charlottesville, showed that the
>synapses of the control rats responded readily to the conditioning,
>smoothly
>transmitting the stimulus again and again over time. In contrast, the
>neurons of rats exposed to lead were not able to establish strong
links
>with
>each other during the conditioning period.
> The third group of rats underwent molecular studies to
determine
>exactly what part of the neuron was being changed by lead. The
researchers
>focused on a tiny portion of the neuron called the NMDA receptor, long
>known
>to play an important role in learning and memory. This experiment
showed
>that long-term exposure to lead in adult rats alters the expression of
>particular genes and proteins that make up the NMDA receptor.
> "We believe that lead, by decreasing these NMDA receptors, is
>interfering with calcium's entry into the neuron," says first author,
>Michelle K. Nihei, PhD, research associate, Environmental Health
Sciences,
>Johns Hopkins School of Public Health. "This is noteworthy since
calcium is
>responsible for a huge cascade of cellular signals that ultimately
>propagate
>information and continue the nerve impulse on to the next synapse and
>neuron."
> This was the first study to show not only that the NMDA
receptor in
>animals was changed by lead, but also that the problems in learning
and
>within the neuronal connections themselves were due to lead poisoning.
The
>authors go on to say that studies like this one significantly advance
the
>understanding of lead neurotoxicity and, perhaps more importantly, may
>guide
>researchers in the right direction to find interventions to ameliorate
the
>consequences of childhood lead poisoning.
>* * *
>
>FEAT to Newsweek on Autism: We Still have to Fight
>
> Despite years of overwhelming proof of the educational and
fiscal
>efficacy of early, intensive ABA based intervention programs, many
families
>must still fight through lengthy and costly Due Process hearings to
get
>quality services delivered. This conduct by some school districts and
>governmental agencies (which is often in violation of Federal and
State
>laws) is carried out by public agencies entrusted with providing
services
>and advocating for persons with developmental disabilities. While the
>families wait, the autistic child slips further away from reaching
their
>potential.
> If public school programs are to meet the needs of autistic
>children,
>they must provide an intensity of service that does not fit into the
>traditional school day. Programs must be run year round by highly
trained
>autism staff. Some districts could better outsource to a non-public
entity
>that specializes in the field. Instead, many public schools refuse to
fund
>outside programs yet spend tax dollars for attorneys to fight parents.
> The children who are diagnosed with autism today will affect
their
>community for most of this century. The child we shortchange today
will be
>far more expensive to care for during the majority of his life.
Morally and
>fiscally, we as a society cannot afford to let the potential of these
>precious lives slip away.
>
>Nancy Fellmeth
>President, Families for Early Autism Treatment (FEAT)
>Sacramento CA
>______________________________________________________
> UC Davis M.I.N.D. Institute:
> http://www.mindinstitute.org
>
>Editor: Lenny Schafer | Eastern Editor: | News Wire: Ron
Sleith
>schafer@sprynet.com | Catherine Johnson PhD | News: Kay
Stammers


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