Archives for posts with tag: Carlos Sonnenschein

From Metro (quoting Upstream Expert, Dr. Carlos Sonnenschein):

The synthetic chemical bisphenol A, which is used in the linings of beer, soda and food cans, plus plastic water bottles, has been exposed as a hormone disrupter and linked to autism, cancer and other complications in the body. But it might be just the tip of the iceberg of toxic chemicals impacting us every day.

“There are 80,000 chemicals in everyday use that have never been tested,” says Dr. Carlos Sonnenschein of Tufts University School of Medicine’s Department of Anatomy and Cellular Biology. “It really is a nightmare.”

Despite decades of research supported by the National Institute of Environmental Health Sciences on the harmful effects of BPA and other endocrine disruptors, Dr. Sonnenschein says that “very little has been done about it where it counts for the public, that is, at the regulatory end (EPA, FDA).”

Dr. Sonnenschein urges the public to get involved in banning toxic ingredients because “nothing will change,” he says, “without protests before officials who run for local, state and national office. The public has an important stake in this.”

The potential effects of such ingredients are widespread: “Hormonal disruptors, at their most radical, cause fetal damage during pregnancy. There’s more incidence of breast cancer as there’s more exposure. [Pubescent girls] are particularly sensitive to exposure. But, throughout our lives, continuous exposure means the body is storing the chemicals in fat tissue,” Dr. Sonnenschein adds.

“Most people are fed up with all these chemicals. The evidence is there. It is time for the regulatory agencies to act to protect the people.”

BPA: here to stay

Despite a lawsuit from the international nonprofit Natural Resources Defense Council, the FDA recently ruled to continue allowing BPA in food packaging. The NRDC’s public health
program’s senior scientist, Dr. Sarah Janssen, responded in a statement, which in part read:

“We believe FDA made the wrong call. The agency has failed to protect our health and safety — in the face of scientific studies that continue to raise disturbing questions about the effects of BPA exposures, especially in fetuses, babies and young children. The FDA is out-of-step with scientific and medical research. This illustrates the need for a major overhaul of how the government protects us against dangerous chemicals.”

More.

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From Oregon Live (mentioning the work of Upstream contributor, Dr. Carlos Sonnenschein):

Though the chemical is the object of much public outcry and caused many retailers to remove products containing BPA from their shelves, for many, questions surrounding the chemical remain unanswered. What exactly is BPA? What, if any, are its potential dangers for adults?

According to the Food and Drug Administration, the plastic known as bisphenol A, has been used in many consumer products including reusable drinking bottles and baby bottles as well as in the lining of metal cans. According to the Professor Carlos Sonnenschein, Tufts University, Boston, fetal and neonatal exposure to the chemical increases the likelihood of development of malignant tumors later in life. Other studies have connected it to both breast and prostate cancers.

In January of 2010, the FDA issued a statement regarding its current position on BPA, recognizing that research interpretation is at best, uncertain. “These uncertainties relate to issues such as … differences in the metabolism (and detoxification) of and responses to BPA both at different ages and in different species, and limited or absent dose response information for some studies,” it read.

Six months later, in July of 2010, the Environmental Working Group issued a study that found high levels of what they call the “endocrine-disrupting” chemical in 40 percent of receipts sampled from such outlets as McDonalds, CVS, KFC, Whole Foods, Walmart and the U.S. Postal Service.

“A typical employee at any large retailer who runs the register could handle hundreds of the contaminated receipts in a single day at work,” said Jane Houlihan, EWG Senior Vice-President for Research. “While we do not know exactly what this means for people’s health, it’s just one more path of exposure to this chemical that seems to bombard every single person.”

Though other major retailers such as Target, Starbucks and Bank of America ATMs appear to not be using BPA to coat their receipts, determining whether a receipt has BPA can be difficult.

As of November 8, 2010, Appleton Inc., the nation’s largest and only producer of BPA-free, thermal paper announced the introduction of “easy-to-see red fibers” to its products. Appleton had dropped the use of BPA in its papers in 2006, but now adds the red fibers as a way to give consumers an easy way to detect the chemical.

In 2008, the National Toxicology Program and the NTP Center for the Evaluation of Risks to Human Reproduction warned of “some concern for effects on the brain, behavior and prostate gland in fetuses, infants and children at current human expo­sures to bisphenol A.”

More.

From Chemical & Engineering News:

Bisphenol A—an estrogen-mimicking chemical found in baby bottles, food containers, and household electronics—has been linked to a host of health problems in animals and people. Now researchers have detected it in the environment and urine of young children, revealing that preschoolers absorb BPA primarily through the food they eat.

Manufacturers use BPA to make plastics and epoxy resins, and BPA can leach from products containing these materials into food, beverages, dust, and air. Numerous studies, mostly conducted on animals, have linked high levels of the endocrine-disrupting chemical to conditions such as cancer, obesity, heart disease, infertility, and neurological disease.

Although scientists think that developing organisms are the most susceptible to BPA’s potential toxic effects, few studies have examined BPA exposure in young children, says Linda Sheldon, associate director at the U.S. Environmental Protection Agency. So in 2000 and 2001, Sheldon, Marsha Morgan, an EPA research scientist, and their colleagues joined forces to measure children’s exposures to BPA and other chemicals in an EPA study called Children’s Total Exposure to Persistent Pesticides and Other Persistent Organic Pollutants (CTEPP). They collected samples of solid and liquid foods, air, dust, and soil from the homes and daycare centers of 257 children between the ages of 2 and 5 in North Carolina and Ohio.

. . . . The researchers showed that the children’s solid and liquid foods contained the highest amounts of BPA. However, says Morgan, “at the time we collected the samples, we weren’t able to quantify BPA in urine with existing analytical methods.” Scientists at the U.S. Centers for Disease Control and Prevention developed a mass spectrometric method to do just that, so Morgan and Sheldon sent a subset of frozen urine samples to CDC scientists for analysis.

Consistent with studies done in other countries, the researchers detected BPA in all of the 81 urine samples from preschool-aged children in Ohio. However, even the highest urinary BPA concentration measured, 0.21 mg/L, was well below the maximum level EPA considers safe: 2 mg/L BPA in human urine. The researchers used statistical analysis to show that the children’s excreted amounts of urinary BPA correlated with the doses they received through their food. The team discovered that dietary ingestion accounted for more than 95% of the BPA excreted in the preschoolers’ urine.

[Upstream Expert] Carlos Sonnenschein, a cell biologist at Tufts University School of Medicine, commends the researchers for their “rigorous experimental approach.” He says, “I consider this paper of great importance because it conveys evidence necessary for public health officials and politicians to react” and develop regulations that will keep BPA out of food.

More (including links).

In my interview of Drs. Carlos Sonnenschein and Ana Soto, I asked them about some of their favorite authors and writings on the topic of environmental health.  This video contains their responses, which are also included with links below (duration: 11:34).

Dr. Soto’s Five Favorites:

Dr. Sonnenschein’s Five Favorites:

The full, edited interview is now available on the Upstream Website.

In my recent interview of Drs. Carlos Sonnenschein and Ana Soto, I asked them about how they thought chemicals and the chemical industry should be regulated to better protect human health. Here is the second of two portions of that exchange (duration: 14:27).

Drs. Sonnenschein and Soto respond to the following prompts:

  1. How can a consumer live safely in a toxic environment? 00:40
  2. Can you give me an example of a specific regulation that you would like to see enacted? 03:50
  3. Do we need to change our regulatory mindset in this country? 04:20
  4. What do you mean by the “white paper” approach to regulating chemical?07:50
  5. What is green chemistry? 10:20
  6. What are the impediments to effective regulation, and how is that we overcome them? 11:00

The full, edited interview is now available on the Upstream Website.

In my recent interview of Drs. Carlos Sonnenschein and Ana Soto, I asked them about how they thought chemicals and the chemical industry should be regulated to better protect human health. Here is the first of two portions of that exchange.

Drs. Sonnenschein and Soto respond to the following prompts:

  1. How would you describe the U.S. system of chemical regulation? 00:40
  2. Please describe the “precautionary principle” used in some other countries. 02:10
  3. What is the biggest difference between our regulatory approach and one based on the precautionary principle? 05:50
  4. Why has the U.S. government not caught up with science and employed the precautionary principle? 06:50
  5. What role is the public playing in this issue? 08:10
  6. Are there are any public actors who are making a difference? 10:15
  7. We have made some progress, right? 11:00

The full, edited interview is now available on the Upstream Website.

In my recent interview of Drs. Carlos Sonnenschein and Ana Soto, I asked them about their research on endocrine disruptors. Below is the clip from that portion of the interview.

Drs. Sonnenschein and Soto respond to the following prompts:

  1. What are endocrine disruptors and what effects do they have? 00:40
  2. Are all endocrine disruptors estrogenic? 02:20
  3. How do you determine if a compound is an endocrine disruptor? 03:30
  4. How did scientists first discover the endocrine-disrupting effects of synthetic estrogens? 04:10
  5. Describe the research on endocrine disruptors since then? 05:30
  6. Can you say more about the DES experience and the lessons learned from it? 07:10
  7. What might experiments on rodents teach us about the risks of endocrine disruptors for humans? 010:30
  8. What other risks have scientists attributed to BPA? 12:30

The full, edited interview is now available on the Upstream Website.

In my recent interview of Drs. Carlos Sonnenschein and Ana Soto, I asked them about Bisphenol A (BPA). Below is the clip from that portion of the interview.

Drs. Sonnenschein and Soto respond to the following prompts:

  1. Describe why you changed your focus to BPA. 00:40
  2. What was the original purpose of BPA? 03:15
  3. Where do humans come into contact with these BPA-laden plastics? 04:30
  4. Do you think the public fully appreciates the magnitude of this problem? 06:35

In their responses, they discuss how they discovered several estrogenic chemicals and why BPA became the primary focus of their research in the 1990s.  They explain the origins of BPA, including the fact that it was originally synthesized to be an estrogen, though it was ultimately used in the synthesis of plastics.  They also describe the ubiquity of BPA in our products — including in plastic water bottles, dispersants in inks, and sealants in teeth.

The full, edited interview is now available on the Upstream Website.

* * *

I recently interviewed Drs. Carlos Sonnenschein and Ana Soto.

This video contains the introduction to that interview, in which they responded to the following prompts:

  1. Describe your work before you began studying environmental toxins. 00:00:40
  2. What caused you to shift the focus of your research? 00:02:35
  3. Please say more about the unexpected results in your lab and how you responded.00:04:25
  4. Without the manufacturer’s assistance, how did you discover what the contaminant was? 00:06:25
  5. What is the contaminant, and how is it used? 00:07:55

Through their responses, Drs. Sonnenschein and Soto tell the fascinating story of how a laboratory accident caused them to stop their research and pursue a new project that would eventually reveal to them how plastic tubes were producing estrogenic activity and set them down a new research path.  They also describe how they came to realize that the “problem [of estrogenic activity] was probably much more serious” than they first suspected.

The full, edited interview is now available on the Upstream Website.

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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