X-Message-Number: 507
From:	Ralph Merkle <>
Subject: Bruce Ames Aging and Cancer talk at Xerox PARC
Date:	Mon, 21 Oct 1991 10:54:12 -0700

PARC Forum
Date:  Thursday, Oct. 24, 1991
Time:  4:00 p.m (Refreshments at 3:45 pm)
Place:  PARC Auditorium


Professor Bruce N. Ames
University of California, Berkeley, CA

Daily endogenous oxidative DNA damage is enormous.  A normal young rat cell has
about 106 oxidative adducts and this number increases with age.  About 105 new
oxidative adducts per cell are formed every day, most of which are repaired.
These are the same types of adducts that are produced by radiation, an
oxidative mutagen.  We conclude that endogenous oxidative damage is a major
factor in aging and the degenerative diseases associated with aging, such as
cancer, heart disease, brain deterioration, and cataracts.  We discuss the role
of various antioxidants in preventing cancer and the degenerative diseases of
aging.  We also discuss why mitogenesis is critical for mutagenesis and why
agents increasing either mitogenesis or mutagenesis are expected to be
The known and likely causes of cancer are discussed, as well as the
contributions of epidemiology and the testing of chemicals in animals to the
understanding of causes of cancer in humans.  There are large numbers of
mutagens and carcinogens in the environment, such as rancid fat, natural toxic
chemicals present in all plants as defenses against insects, cooked food, and
manmade chemicals, but the meaning of this for human health is not clear as
half of all chemicals tested, whether synthetic or natural, are carcinogens in
high dose rodent tests.  We think this is because high dose animal cancer tests
might commonly increase mitogenesis.  In the evolutionary war between plants
and animals, animals have developed layers of general defenses, almost all
inducible, against toxic chemicals.  This means we are well-buffered against
toxicity at low doses from both manmade and natural chemicals.  Low doses of
carcinogens (as defined by  high-dose rodent tests) appear to be both much more
common and less  hazardous than is generally thought.

This Forum is OPEN to the public.  All are invited.

For more information contact Warren Jackson at [415] 812-4196,
Requests for videotape, contact Susie Mulhurn at 812-4068
Refreshments will be served at 3:45 pm.

The PARC Auditorum is located at 3333 Coyote Hill Rd. in Palo Alto.  We are
between Page Mill Road (west of Foothill Expressway) and Hillview Avenue, in
the Stanford Research Park.  The easiest way here is to get onto Page Mill
Road, and turn onto Coyote Hill Road.  As you drive up Coyote Hill past the
horse pastures, PARC is the only building on the left after you crest the hill.
Park in the large parking lot, and enter the auditorium at the upper level of
the building.  (The auditorum entrance is located down the stairs and to the
left of the main doors.)

CARPOOLING FROM THE SSU IN SUNNYVALE: Meet at 3:20 in the Main Break Room,
Bldg. 5, Room 523.

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