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 UNDERSTANDING THE CAUSES OF AGING AND CANCER 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 carcinogens. 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. ----- End Included Message ----- Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=507