3-D Dental X-Rays Pose Radiation Concern

From The New York Times.

Because children and adolescents are particularly vulnerable to radiation, doctors three years ago mounted a national campaign to protect them by reducing diagnostic radiation to only those levels seen as absolutely necessary.

It is a message that has resonated in many clinics and hospitals. Yet there is one busy place where it has not: the dental office.

Not only do most dentists continue to use outmoded X-ray film requiring higher amounts of radiation, but orthodontists and other specialists are embracing a new scanning device that emits significantly more radiation than conventional methods, an examination by The New York Times has found.

Read the story.

For a quick look at common sources of radiation in the U.S., click here.

Los Angeles County To Ban Plastic Bags

From The Los Angeles Times:

The Los Angeles County Board of Supervisors voted Tuesday to ban plastic grocery bags in areas of the county under its jurisdiction, endorsing a broadly worded measure that proponents hope could become a model for California.

The ban, which goes beyond ordinances adopted in Malibu and San Francisco, most directly affects 1.1 million people who live outside the county's incorporated cities. But anyone shopping at stores in such areas would encounter the new rules.

Opponents suggested they might go to court to try to block the ban before the first phase takes effect in July, when 67 large supermarkets and pharmacies must stop providing disposable plastic bags. By January 2012, the ban will cover 1,000 stores throughout the county. The ordinance also seeks to keep shoppers from turning to paper bags as an alternative by requiring stores to levy a 10-cent surcharge per paper bag.

Hunting Clones In the Caucuses

A mature fig treeNot all government workers are desk jockeys or time-card punchers. Consider Malli Aradhya, a geneticist in the employ of the U.S. Deparmtent of Agriculture. He travels around the globe to find perfect fruit specimens to bring back to the States for study and, one day, possibly harvest. The Smithsonian recently got to tag along:

To botanists, this region of the Caucasus Mountains is known as a center of diversity for figs as well as mulberries, grapes, walnuts, apricots, pomegranates and almonds. All have grown here for millennia and through constant sexual reproduction have attained a tremendous range of genetic diversity, the variation easily seen on a walk through most villages or a visit to a large fruit bazaar.

It’s precisely this spectrum of colors, shapes, sizes and flavors that has drawn Malli Aradhya to the lowlands of the Republic of Georgia, a former Soviet nation banking the Black Sea and just south of the Greater Caucasus Mountains. He is a geneticist with the U. S. Department of Agriculture, and this is his fifth fruit-hunting expedition to the region in six summers. His objective: to collect tree crop varieties, transport them home as seeds and wood cuttings and—after the samples pass through federal and state inspection sites—propagate them at the USDA’s Wolfskill Experimental Orchards in Winters, California. This 70-acre varietal library, operated in conjunction with a test nursery at the University of California at Davis, is home to two “copies” each of several thousand plant accessions, many collected on excursions like this one. Aradhya himself has brought home some 500 of them on four trips to Azerbaijan and Kyrgyzstan.

Still, the collection, part of the National Clonal Germplasm Repository program, has its holes. Aradhya wants, for example, new rootstock varieties of pistachio, a blight-resistant walnut and figs sweet enough to sell yet sturdy enough to handle the bumpy rigors of post-harvest transportation—and all may exist in the orchards, villages and wild lands of Georgia.

The scientist is still jet-lagged by a 24-hour spell of travel when he visits a farmers market in the Gldani District of Tbilisi, the nation’s capital. Following behind two fruit geneticists from the Georgian Institute of Horticulture, Viticulture and Oenology, Aradhya eyes the heaps of apples, plums, nuts and figs with the discerning attention of, well, a fruit geneticist.

Read the full story here.

BPA Linked to Diabetes

Cash register receipts are a major source of BPAMounting evidence continues to point to pollution's contribution to the obesity epidemic. In yet another study, the pollutant BPA has been identified as a cause of decreased glucose tolerance (ability to break down and eliminate sugar from the bloodstream) and the insulin resistance syndrome associated with diabetes and obesity. Previous studies have linked BPA to deleterious effects on the  brain, behavior and prostrate gland of fetuses, infants and children.

Despite the American Chemical Society's attempts to downplay rising concerns, this study in the National Institute of Health peer-reviewed journal, Environmental Health Perspectives, is yet another nail in the coffin for BPA, which the Centers for Disease control reports can be found in the bloodstream of most Americans and is commonly ingested by consuming foods that come in contact with plastic (either through plastic storage containers, wraps, bottles or cans lined with plastic) or by handling BPA-laden cash register receipts.Eden Organic offers BPA-free canned foods.

In this mouse study, environmentally relevant exposure to BPA (meaning the low level exposure experienced by the average person as opposed to the high level of exposure more commonly used in testing for pollutant's health effects) aggravated insulin resistance produced during pregnancy and was associated with decreased glucose tolerance and increased plasma insulin, triglyceride, and leptin concentrations relative to controls. The authors concluded: "Our findings suggest that BPA may contribute to metabolic disorders relevant to glucose homeostasis and that BPA may be a risk factor for diabetes."

The study was conducted at biomedical research universities in Spain, which may be one clue as to why it didn't make headlines in the U.S. Already, France and Denmark have placed restrictions on BPA in infant feeding bottles. The EU health Commissioner, John Dalli, recently indicated his agency may follow suit.  The Canadian government has added the compound to a list of substances deemed harmful to health, in preparation for further regulatory action. The FDA sends a mixed message: "FDA shares the perspective of the National Toxicology Program that recent studies provide reason for some concern about the potential effects of BPA on the brain, behavior, and prostate gland of fetuses, infants and children." But as yet the agency has failed to take action by recommending any restrictions on manufacturing and production of products that expose people to BPA, not even taking action against BPA-laden baby bottles.

Dr. Merrell's Take: Look for bottles and cans labelled BPA-free. Store food in glass containers. Do not allow saran wrap to touch hot foods (or any food if you can help it.) Keep cash register receipts out of food bags, and make sure to wash your hands after handling them. Finally, don't let your baby suck on plastic toys. 

Hand Washing: For Removing Bacteria, Paper Towels Beat Hand Dryers

Dyson and his Airblade hand dryer.This probably wasn't exactly the result the hand-dryer-making company, Dyson, was looking for when they funded this small study on hand washing. Anna Snelling of the University of Bradford, UK asked 14 volunteers to dry their hands for 15 seconds using either paper towels or three different typs of air dryer, sometimes rubbing their hands together and sometimes not. When volunteers kept their hands still (which is how the extremely loud Dyson dryers work) skin bacteria numbers dropped by roughly 37% compared to just after washing; however, paper towels knocked out the bacteria by half. That's because the towels actually scraped off the bacteria. In a partial victory for Dyson, when volunteers rubbed their hands together under a standard hand dryer, the bacteria count actually rose by 18%. So drying with a Dyson-type dryer was more sanitary than a standard hand-dryer, but paper towels won, hands down.

View the study.