Subject: pesticides we don't understand (fwd)

From: Victor Guest <[email-masked]>
Date: Tue, 27 May 1997 09:29:38 WST

A friend of mine sent me this. I thought it might be of interest to others.
I had always thought that Round-Up was safe, but it does operate on a
growth-hormone principle, if I'm correct. What do you think?

Barbara
>
>FROG DEFORMITIES
>      By DAVID REED
>      STONY MAN MOUNTAIN, Va. (AP) - In an isolated mountaintop lodge
>with the lights turned down, 80 scientists from the United States
>and Canada clustered around a projector to view slides of
>misshapen, mutant frogs.
>      The scientists looked at frogs with legs protruding from their
>stomachs and frogs with no legs at all. They heard about frogs with
>eyes staring disconcertingly from their backs and frogs with
>suction-cup fingers growing from their sides.
>      What, they wanted to know, is causing the gross deformities
>turning up with alarming frequency in North America's frogs? And if
>they are the victims of a tainted environment, they wondered, can
>humans be far behind?
>      ``Maybe these frogs are pointing out that there is a more
>widespread problem,'' suggested Kathy Converse of the National
>Wildlife Health Center in Madison, Wis.
>      There have been reports of unusually high numbers of deformed
>frogs in Minnesota, Vermont, Wisconsin and Quebec. Clusters of
>deformed frogs have also been found in California, Oregon,
>Colorado, Idaho, Mississippi, Montana and Ohio.
>      At the conference last month in Shenandoah National Park,
>scientists ranging from molecular biologists to herpetologists
>examined theories that link the frog deformities to chemicals or
>parasites.
>      ``My best guess is that it has more to do with pesticides,''
>Martin Ouellet of McGill University in Montreal said.
>      Ouellet and four other scientists have been studying deformed
>and normal frogs found in more than 100 ponds in the St. Lawrence
>River Valley during the past four years.
>      Normally, less than 1 percent of frogs are deformed, and that's
>about what Ouellet found in frogs taken from pristine ponds. But in
>ponds where pesticides are used on surrounding land, as many as 69
>percent of the frogs were deformed, he said.
>      If a pesticide is causing deformities, it's probably a new brand
>because large numbers of frog deformities have not been noticed
>before, Ms. Converse of the Wildlife Health Center said.
>      ``It's less likely to be one of the older chemicals, like DDT or
>PCBs,'' she said.
>      David Gardiner, a molecular biologist from the University of
>California at Irvine, believes that the deformities may be linked
>to a new generation of chemicals that mimic growth hormones.
>      Gardiner said the same kind of frog deformities that have been
>found in marshes and ponds - including extra legs and eyes - have
>been replicated in laboratory experiments.
>      ``I can make a frog that looks like any frog you've seen at this
>meeting,'' said Gardiner, who specializes in cell regeneration.
>      Scientists have induced the deformities with retinoic acid, a
>byproduct of a workhorse chemical called retinoid that is found in
>acne medicine and skin rejuvenation creams.
>      Retinoids powerfully effect development, and if they are inside
>a growing animal at the wrong place at the wrong time, they can
>cause deformities, he said. That's why pregnant women are warned
>not to use skin medicines that contain retinoids.
>      Recent laboratory experiments have determined that a pesticide
>can mimic a retinoid and, conceivably, cause defects in frog
>development, he said.
>      ``We should start screening chemicals, and we should start with
>pesticides, to see if they mimic naturally occurring retinoids in
>the body,'' Gardiner said.
>      Stan Sessions, a developmental biologist, questioned whether a
>chemical could be the culprit because there were no deformed fish
>or other animals found in the ponds where the deformed frogs were
>captured.
>      He believes parasites cause the deformities.
>      Sessions, a professor at Hartwick College in Oneonta, N.Y., put
>a three-legged frog recently found in Vermont under a microscope
>and invited his colleagues to share in his discovery.
>      In his partially dissected specimen, tiny parasitic flat worms
>were packed into the joint where the frog was missing a leg.
>Sessions told of a lab experiment in which he mimicked the invasion
>of parasites in a tadpole and caused it to sprout an extra leg as
>it developed into a frog.
>      ``The mystery is beginning to resolve itself,'' Sessions said.
>      Some scientists in Oregon, trying to unravel the riddle of
>deformed frogs in that state, decided that trematodes, a parasite
>commonly known as flukes, were burrowing into the places where legs
>form when the frogs are tadpoles, causing additional legs to grow.
>      Some of Sessions' colleagues at the conference were intrigued
>and some said he was on to something. But others were skeptical.
>      Finding the answer to the deformed frog mystery will probably
>take three to five years of research, said Joe Tietge, conference
>organizer and research biologist for the U.S. Environmental
>Protection Agency laboratory in Duluth, Minn.
>      One of the goals of the conference was to direct research,
>Tietge said. The scientists at the meeting determined what kind of
>data will be included in a national reporting system that the U.S.
>Geological Survey is developing.
>      At the end of May, the EPA and other federal agencies will award
>grants to scientists studying the phenomenon of the deformed frogs.
>      Copyright 1997 The
>Associated Press.
>
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