Bypassing surgery might be possible

OBESITY

Controlling obesity in our country has proven difficult. Drugs, diet, and behavioral changes are difficult to sustain. Gastric bypass surgery, where surgeons exclude part of the stomach and the intestine from the flow of food, is effective, but comes with several side effects.

Now, a novel device from the Massachusetts General Hospital Weight Center offers the benefits of bypass surgery without the side effects, researchers say. "We wanted something that would replicate the useful parts of the bypass operation, without actually requiring us to perform a bypass," said Dr. Lee Kaplan, the principal investigator. What they came up with was a small, 10 centimeter impermeable sleeve that fits into the first part of the small intestine. It is designed to disrupt the signals important in regulating appetite.

Researchers implanted the device in eight obese rats. Over the next several weeks, those rats lost 20 percent more weight and consumed 30 percent fewer calories than the control rats. Further, the treated rats had lower fasting blood sugar levels and normal insulin levels, an important finding since unchecked obesity often leads to the development of diabetes.

"Hopefully this is a step toward bypassing the gastric bypass operation," says Kaplan. Trials for the device in humans are already underway, he said.

BOTTOM LINE: Placing a short, impermeable sleeve into part of the small intestine in rats mimics the weight loss benefits of gastric bypass surgery.

CAUTIONS: The study was done in rats, and the device was placed surgically. In humans, it would be fed into the small intestine with a tube inserted through the mouth.

WHAT'S NEXT: Further research is needed to prove the utility of the sleeve in combating obesity in humans.

WHERE TO FIND IT: Obesity, November 2008.

SUSHRUT JANGI

EVOLUTION

A team of researchers from China, Canada, and the United States have uncovered a 220 million-year-old turtle fossil that they say could solve the mystery of how the animals form their shells. The fossil, discovered in southwestern China in 2007, has several unusual features including teeth and only half a shell, which scientists maintain identify it as the most primitive turtle ever found.

Modern turtle shells have two components: a hard plate below the body, called the plastron, and a top shell, called the carapace. Scientists disagree on which part of the shell formed first, an argument this study ends, says study coauthor Xiao-Chen Wu, a paleontologist with the Canadian Museum of Nature in Ottawa. The specimen, named Odontochelys semistestacea, has a plastron, but no carapace. The plastron formed first, Wu says, followed by a widening of the ribs and backbone, which formed the upper shell. This growth process is seen in embryos and hatchlings of turtles today. What's more, Wu adds, the presence of a plastron suggests the animal originated in water, not on land, as earlier theories suggest. A bottom shell would offer the aquatic animal an evolutionary advantage against predators, which attack from below.

BOTTOM LINE: Studies of an ancient turtle fossil suggest the animals originated in water and belonged to the same reptile group as crocodiles, lizards, and dinosaurs.

CAUTIONS: It's impossible to know for sure if this turtle represents the first of the species and originated in water, or if it is an example of a terrestrial turtle that shed its upper shell to live in water.

WHAT'S NEXT: The researchers plan further analysis of the fossil, which they say could provide additional evidence of the turtle's origin.

WHERE TO FIND IT: Nature, Nov. 27, 2008

KELLI WHITLOCK BURTON