Discovery

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Posts Tagged ‘mouse’

Hormones and Plastics: Act II

More than most people, WSU’s Patricia Hunt helped make the plasticizer bisphenol A, also known as BPA, a household word.

OK, that might be pushing the point, but the WSU biologist did get lots of people to wonder if a lot of widely used plastic bottles might be bad for them. It was Hunt who, back in 1998, connected genetic abnormalities in lab mice with a substance—BPA—that a detergent released from their cages and water bottles. This spring, Washington became the fifth state to outlaw the chemical in children’s food containers and drinking cups, with the measure taking effect in July, 2011. A ban on sports water bottles with the chemical takes effect the following July.

But wait, there’s more.

Last month, Japanese researchers reported in the journal Environmental Health Perspectives that a similar compound, bisphenol AF, has a similar ability to the body’s ability to use the hormone estrogen. Moreover, the study found the flourines accounting for the “F” in bisphenol AF are an order of magnitude more effective than bisphenol A at binding to two major estrogen receptors. One reporter referred to the compound as “BPA’s fluorinated twin — on steroids.”

WSU Biologist Patricia Hunt

The study is another strong piece of evidence that such chemicals need to be kept away from humans, says Hunt:

“We have a lot of evidence from studies of BPA that exposure to low doses (doses that we think mimic current levels of human exposure) cause significant changes in the developing fetus.  There is also good evidence that the changes induced in the developing fetus can lead to behavioral changes, decreased fertility and an increase in diseases like breast and prostate cancer in the adult.

“Given these findings, this new study of the related compound, BPA-F, raises tremendous concerns because it suggests that BPA-F is likely to be even more hazardous to our health.  There is a really simple lesson here:  Humans – especially fetuses and babies – should not be exposed to chemicals that can act like or interfere with the actions of hormones.  Using chemicals like BPA and BPA-F in a wide variety of consumer products makes daily human exposure inevitable.”

Citation: Matsushima A, Liu X, Okada H, Shimohigashi M, Shimohigashi Y 2010. Bisphenol AF is a Full Agonist for the Estrogen Receptor ERα, but a Highly Specific Antagonist for ERβ. Environmental Health Perspectives. doi:10.1289/ehp.0901819

Patricia Hunt’s Center for Reproductive Biology web page is here.

A Better Mouse Pain Picture

Loyal readers will recall Friday’s post in which Stephen Greene, professor in anesthesiology at WSU’s College of Veterinary Medicine, commented on the first study of how a non-human animal’s face can express pain. Its publisher, Nature Methods, has kindly granted us permission to show a great set of pictures showing the “mouse grimace scale” that may some day be put to use in drug testing and veterinary care.

The "mouse grimace scale," according to the authors, "may provide insight into the subjective pain experience of mice."

Photo courtesy of Nature Methods and Dale J Langford, Andrea L Bailey, Mona Lisa Chanda, Sarah E Clarke, Tanya E Drummond, Stephanie Echols, Sarah Glick, Joelle Ingrao, Tammy Klassen-Ross, Michael L LaCroix-Fralish, Lynn Matsumiya, Robert E Sorge, Susana G Sotocinal, John M Tabaka, David Wong, Arn M J M van den Maagdenberg, Michel D Ferrari, Kenneth D Craig & Jeffrey S Mogil, authors of “Coding of facial expressions of pain in the laboratory mouse.”

A Better Mouse Pain Map

Photo courtesy of iklash via Flickr--http://www.flickr.com/photos/klash/

Animal pain has intrigued scientists for centuries, with questions ranging from whether they feel it at all–no kidding–to just how to gauge it. To state the obvious, they can’t talk, nor can they point to the smiley and not-so-smiley faces on a pain chart.

Canadian and Dutch researchers took a big step forward this week with the first study of how a non-human animal’s face can express pain. Putting mice in painful situations, they videotaped their reactions and documented bulging cheeks and noses, squinting eyes, and shifting ears and whiskers. Categorizing these gestures in levels of no pain, moderate pain, and severe pain, they created a “mouse grimace scale” for use in drug testing and veterinary care.

We brought this to the attention of Stephen Greene, a professor in anesthesiology at WSU’s College of Veterinary Medicine, who has naturally made animal pain a central concern of his career. It turns out he has long been teaching veterinary students a range of methods of gauging an animal’s discomfort.

“The mouse study is interesting,” he said. “We teach veterinary students that recognizing pain in each species is an important step in developing successful analgesic therapies. In the clinical setting, behavioral cues such as food and water consumption, posture, activity level, and vocalization are used to categorize the degree of pain in animals. Physiologic variables like heart rate and blood pressure also contribute to the pain assessment. The development of the mouse grimace scale appears to be a reliable metric of pain (in the mouse) that will likely contribute to better understanding and treatment of pain in many other species.”

Nature Methods , 2010. DOI: 10.1038/nmeth.1455