Findings

Just Found

These stories describe NIGMS-funded medical research projects. Although only the lead scientists are named, they work together in teams to do this research.

Shrew-ed Science

What do deer, mice, and shrews have in common? Easy—they all live in the woods.

But these forest dwellers are alike in another way that isn't so cheery: They all spread Lyme disease.

Deer pick up ticks from mice that drop the teeny bugs onto leaves and sticks. Humans and pets get Lyme disease when bacteria-infected ticks attach to skin and eat a blood meal. Until now, scientists thought mice were the main source, or "reservoir," of the bacteria that cause Lyme disease.

Two varieties of shrews can now be held to blame, according to new findings from evolutionary geneticist Daniel Dykhuizen of Stony Brook University in New York.

Dykhuizen's student Dustin Brisson showed that in the Northeastern United States, mice carried only 25 percent of the ticks that carry Lyme disease. Shrews carried 55 percent of those ticks, while chipmunks and other small birds and rodents likely accounted for the rest.

The study results suggest that public health strategies targeted at interrupting tick transmission in shrews and chipmunks, in addition to mice, may help prevent Lyme disease in people. —Alison Davis

Garlic: To Your Health!

Garlic-infused cuisines, such as those from the Mediterranean and Asia, have been linked to good health. Previous studies have shown that garlicky diets reduce cholesterol and lower blood pressure.

Researchers have suspected that allicin, a natural component of garlic released when the cloves are crushed, could be the pungent herb's "healthy" ingredient.

But allicin is an unstable molecule, breaking down very rapidly in body fluids. This has made it very hard to study and created doubt as to its health benefit.

Changing that view, physiologist David Kraus of the University of Alabama at Birmingham discovered that blood converts garlic-derived allicin into a powerful natural gas, hydrogen sulfide, which relaxes blood vessels.

Using a hydrogen sulfide sensor that Kraus invented, his team measured levels of the gas released from garlic juice-bathed blood cells in a glass chamber. They discovered that blood vessels relaxed in proportion to how much hydrogen sulfide appeared.

Kraus says that in addition to solving the allicin mystery, his method could find use in standardizing garlic dietary supplements. —A.D.

Feeling Cancer

Tumors start out in individual organs: the lungs, the bladder, bone, and so on. After gaining a foothold, cancer cells then travel, or metastasize, to other places in the body.

Cancer is much more difficult to treat after it has spread. Scientists want to know what gives metastatic cancer cells their ability to move around so nimbly.

To investigate further, nanotechnologist James Gimzewski of the University of California, Los Angeles, collected cancer cells from the chest fluid of people with lung, breast, and pancreatic tumors that had spread.

He then used a powerful microscope with a thin, sharp tip on a spring to gently poke individual cells and measure their stiffness. The results showed that metastatic cancer cells were "softer" than healthy ones, presumably so they can maneuver through tight spaces on their way to other spots in the body.

Gimzewski's discovery may offer a more precise way to detect cancer cells, since current methods rely mostly on appearance, which often cannot accurately distinguish between healthy and cancerous cells. —A.D.

Corn Gets an A

It's true—eating carrots can actually help you see better! Orange and yellow vegetables are packed with vitamin A that is important for good vision.

Vitamin A deficiency, which causes blindness, affects nearly 200 million children, mostly in sub-Saharan Africa and other developing countries where fruits and vegetables are scarce. Although corn is a dietary staple in these regions, its vitamin A content varies quite a bit.

To combat this, plant breeders have relied on visual cues—such as the "yellowness" of corn, to select and grow corn with more vitamin A. But the method is not always accurate.

Biologist Eleanore Wurtzel of the City University of New York and her students teamed up with other researchers to find a more accurate way. They discovered genetic markers—changes in corn DNA sequence—that could identify which varieties contain more of the natural plant molecules that make vitamin A.

Wurtzel hopes that in time, her work will lead to simple genetic tests that farmers in developing countries can use to choose the most nutritious corn seeds. —A.D.

Listen to Wurtzel talk about her research at http://publications.nigms.nih.gov/multimedia/wurtzel.mov.

Fix for a Broken Heart?

Embryonic stem cells have the potential to become any of the body's 206 cell types. Scientists are working hard to get these "blank slate" cells to grow into replacement cells for different body organs.

The task has proven to be difficult, but researchers are slowly making progress. In one recent advance, cell biologist Gordon Keller of the McEwen Centre for Regenerative Medicine in Toronto, Ontario, Canada, transformed human embryonic stem cells into immature heart cells.

Keller perfected a concoction of nutrients and proteins that, when added to the embryonic stem cells, forced them to become immature heart cells. He then showed that the young heart cells could grow into all three types of cells that make up a functional, beating heart.

With more research, scientists may be able to coax the immature heart cells into forming new heart tissue, a complex blend of the three cell types. The work will also help researchers understand heart disease and test new medicines to treat it. —A.D.

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