Archives for posts with tag: study

From the Colorado Independent:

At least 22 toxic chemicals, including four known human carcinogens, were found in nine separate air samples taken near natural gas drilling operations by community advocacy and environmental groups in Garfield and La Plata counties in Colorado and the San Juan Basin of New Mexico, according to a new report from Global Community Monitor.

Entitled “GASSED! Citizen Investigation of Natural Gas Development (pdf),” the report details how the air samples, taken near homes, playgrounds, schools and community centers, were analyzed by a certified lab.

“Carcinogenic chemicals like benzene and acrylonitrile should not be in the air we breathe – and certainly not at these highly alarming levels,” said Dr. Mark Chernaik. “These results suggest neighboring communities are not being protected and their long-term health is being put at risk.”

As part of the air-quality study, neighbors of natural gas drilling operations were asked to record various chemical odors, sample the air quality and appeal to various regulators to investigate complaints.

“My husband, pets, and I have experienced respiratory and other health-related problems during the 12 years we have lived on Cow Canyon Road in La Plata County, Colo.,” Jeri Montgomery said of nearby natural gas development. “We believe these health issues are related to the air quality in our neighborhood and in the area.”

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From San Francisco Chronicle:

Environmental factors play a more important role in causing autism than previously assumed and, surprisingly, an even larger role than genetics, according to a new study out of UCSF and Stanford that could force a dramatic swing in the focus of research into the developmental disorder.

The study, published in Monday’s issue of the Archives of General Psychiatry, looked at 192 pairs of twins in California and, using a mathematical model, found that genetics account for about 38 percent of the risk of autism, and environmental factors account for about 62 percent.

Previous twin studies had suggested that autism was highly inheritable, with genetics accounting for roughly 90 percent of all cases worldwide. As such, much recent research into autism has focused on tracking down the genes and unlocking the complex genetic codes that are associated with autism.

“We’re not trying to say there isn’t a genetic component – quite the opposite. But for most individuals with autism spectrum disorder, it’s not simply a genetic cause,” said Neil Risch, director of the UCSF Institute for Human Genetics, who designed the study.

Autism doctors and patient advocates said the study, which will probably be followed up with similar studies of twins and other siblings, could have a significant impact on research into the disorder.

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From PBS NewsHour:

A chemical used to produce baby bottles, cups and plastic packaging may cause male mice to act like females, a new study finds.

Published Monday in the Proceedings of the National Academy of Sciences, the study shows that male deer mice exposed to the organic compound Bisphenol A – or BPA – appeared more anxious and lost their ability to quickly navigate a maze. Both traits are highly uncommon for male deer mice but typical in females, the scientists say.

The male mice also appeared to lose their ability to attract females. At a rate of 2-to-1, test females rejected BPA-exposed males as potential breeding partners, leading the study’s authors to conclude that BPA exposure for males “could impact behavioral cues, pheromone signaling, or both.”

The study is just the latest strike against BPA, which many scientists call an endocrine-disrupting agent that mimics the body’s hormones and causes a slate of health defects in humans. Previous animal studies have found that BPA may accelerate puberty and could lead to cancer, heart disease and diabetes.

Even so, it continues to be widely used in the manufacturing of polycarbonate plastics – especially plastic bottles – as well as in the lining of canned food containers, dental sealants and some medical devices.

In 2008, the Food and Drug Administration said products in the American marketplace did not contain enough of the substance to be dangerous. But that same year, the Department of Health and Human Services’ National Toxicology Program issued a report expressing “some concern for neural and behavioral effects in fetuses, infants, and children at current human exposures.”

Just last week, the American Medical Association adopted a policy at its annual meeting officially “recognizing BPA as an endocrine-disrupting agent and urging that BPA-containing products with the potential for human exposure be clearly identified.” The organization also urged industry leaders to stop producing baby bottles and infant feeding cups with BPA.

Nine states – Connecticut, Maine, Maryland, Massachusetts, Minnesota, New York, Vermont, Washington, and Wisconsin – have BPA bans in place. Legislation is currently in the works to ban the chemical in baby food containers in California and Delaware.

Dr. Retha Newbold, a retired developmental biologist from the National Institute of Environmental Health Sciences, has studied BPA extensively and called the deer mice study “another marker of our sick environment.” But she stopped short of drawing any connections to humans.

“I think we have to be careful when we extrapolate any of these behavior studies in animals to humans,” she said. “But it gives us markers where we can start looking at some of these sexual behavior and cognitive learning processes in humans.”

We spoke with the lead author of the PNAS study, Dr. Cheryl Rosenfeld, associate professor of biomedical sciences at the University of Missouri.

What were you hoping to find in this latest BPA study?

Our guess was that if males are exposed to BPA in utero, when testosterone begins programming the brain, later behaviors would be affected. And we thought that the primary differences might be in sexually selective traits, or behaviors that are differently expressed between males and females. In many species, these are essential to produce offspring but they’re dependent on the development and physical condition of the animal as it’s in the womb and during the postnatal period. So we presumed these traits might be susceptible to BPA exposure.

Did your study mimic the way humans are exposed to BPA?

Yes, we only exposed the mice to BPA through the mother’s diet en utero and while they were nursing. That replicates what’s happening in the real world. Most health organizations agree that our primary exposure to BPA is through diet. A fetus has less ability to metabolize BPA, and it can get from the mother to fetus easily. When we measured the blood BPA concentrations in the females, we found the range of exposure is within the limits of what’s been detecting in humans.

And how does the maze relate to BPA exposure?

When these mice are sexually mature, their brains undergo significant remodeling that allows them to exhibit certain behaviors – like increased spatial-navigational skills in males. In humans, too, men tend to have a better ability than girls to locate in their environment – to know where they are in their environment, to remember where things are and where to find them. So when the males got to adulthood, we started them on behavioral testing in a maze that is well-recognized to test this ability. There are several holes and only one leads to the home cage. Non-BPA exposed males can almost immediately get to the correct hole. The BPA exposed male took quite a bit longer. They didn’t use the most efficient strategy and just wandered around randomly, aimlessly. When we tested the females, both the non-exposed and BPA-exposed females had similar responses. They were acting behaviorally like females.

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