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Paul Mohai, founder of the Environmental Justice Program at the University of Michigan Ann Arbor, discusses his recent research on racial and income disparities in the distribution of hazardous wastes sites in the U.S. Series.

From Fora.TV:

Peter Gleick, scientist and freshwater expert, talks about his latest book: Bottled and Sold: The Story Behind Our Obsession with Bottled Water. Tap water is safe almost everywhere in the U.S. It takes far more water to make the plastic bottle than it even holds. Most bottled water is simply water from somebody else’s tap! Why on earth does this industry continue to thrive?

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Peter H. Gleick is co-founder and president of the Pacific Institute in Oakland, California. Dr. Gleick is an internationally recognized water expert and in 2003 was awarded the prestigious MacArthur Fellowship for his science and policy work on water issues worldwide. In 2006 he was elected to the United States National Academy of Sciences. His research and writing address the critical connections between water and human health, the human right to water, the hydrologic impacts of climate change, sustainable water use, privatization and globalization and international conflicts over water resources.He serves on the boards of numerous journals and organizations and was elected an Academician of the International Water Academy in Oslo, Norway in 1999. Dr. Gleick is the author of many scientific papers and five books, including the biennial water report The World’s Water.

Keynote Address: “Making Climate Change Policy Work Conference” (May 14, 2009)

Manuel Pastor is Professor of Geography and American Studies & Ethnicity at the University of Southern California, where he also serves as Director of the Program for Environmental and Regional Equity (PERE) at U.S.C.s Center for Sustainable Cities and as Co-Director of U.S.C.’s Center for the Study of Immigrant Integration (CSII). Founding director of the Center for Justice, Tolerance, and Community at the University of California, Santa Cruz, he holds an economics Ph.D. from the University of Massachusetts, Amherst.

With the official launch of the Upstream website scheduled to occur next week, for the next couple of weeks, I will be posting stories and quotations about and by the experts in my first interview: Drs. Carlos Sonnenschein and Ana Soto.

Here are excerpts from an article, titled “Ground-breaking Research Leads to New Cancer Theory,” from Environmental Factor, by Brian Chorley (published May, 2010).

* * *

Carlos Sonnenschein, M.D., and Ana Soto, M.D., have dedicated the majority of their research careers to describing the signals that mediate cellular proliferation. On April 20, the researchers presented their findings during a seminar at NIEHS on investigations of chemicals that mimic the biological actions of estrogen. Their talk, “Carcinogenesis: Development Gone Awry,” also presented evidence from their experiments that lend support to a new theory of carcinogenesis.

The current scientific consensus is that cancer-causing agents result in the uncontrolled proliferation of a single cell. Because this paradigm cannot explain all tumors, Soto and Sonnenschein have developed an alternative theory to describe these not-so-uncommon exceptions.

The tissue organization field theory of carcinogenesis

The prevailing sporadic carcinogenesis theory, known as the somatic mutation theory, explains that carcinogens mutate cells that are normally in a non-growing, quiescent state. These mutations lead to a cascade of programmatic errors that cause a state of irreversible proliferation. Therefore a change in a single cell can lead to tumor formation.

Sonnenschein, drawing on the connection between carcinogenesis and tissue development, explained why  this scenario may not always be the case. “Development is not a program,” he said. “Development decisions are made instead by an ad hoc committee.”

In his tissue organization field theory of carcinogenesis, Sonnenschein characterizes cancer as a disease of the tissue organ. Cells, he explained, are in a default state of proliferation and motility — constantly maintaining homeostasis of the tissue through cellular communication and organization. Disruption of this organization can lead to disease states, such as cancer, as carcinogens target whole tissues, not just individual cells.

Sonnenschein’s theory may account for some situations that somatic mutation theory fails to explain. For example, some cancers are not autonomous — that is, the cancerous cells do not control their own fate. Uncontrolled cellular proliferation, therefore, may be signals from the surrounding milieu, not just simply errors in the cell’s replication machinery.

Bisphenol A alters mammary tissue organization

To support this theory, Soto focused on the team’s mammary development studies in rodents exposed to the xenoestrogen, bisphenol A (BPA).

Pre-natal exposure to BPA, a common component of plastics, alters normal mammary gland development in these models. Soto’s findings demonstrated that in mice BPA accelerates mammary maturation by increasing epithelial cell branching, reorganizing connective tissue, and altering fat deposits. In rats, a common animal model for breast cancer, BPA caused pre-cancerous lesions in the mammary tissue.

These lesions were directly linked to tissue disorganization caused by the BPA exposure during gestation and lactation.

The mechanisms are still unclear

While altered mammary development due to BPA exposure led to abnormal cellular proliferation in these rodent models, the cellular signaling mechanisms involved are still being teased out.

Soto described multiple experiments in progress. One exciting finding was that the methylome — the methylation patterns of the genome — changed constantly with BPA exposure. Soto explained that thousands of methylation sites were altered, but these changes were inconsistent over different points of time during and after the BPA exposure. The challenge is to determine if these methylation changes are causative or simply consequences of the tissue disorganization.

Parallel gene expression analysis may solve part of the mechanistic mystery. Soto believes the preliminary results are encouraging. “The molecular results are consistent with the [mammary] histology… the locale and time of [BPA] exposure is of the essence,” she explained.

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