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Archive - May 4, 2012

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Researchers Discover First Gene Linked to Missing Spleen in Newborns

Researchers at Weill Cornell Medical College and Rockefeller University in New York City have identified the first gene to be linked to a rare condition in which babies are born without a spleen, putting those children at risk of dying from infections they cannot defend themselves against. The gene, Nkx2.5, was shown to regulate genesis of the spleen during early development in mice. The study, published online on May 3, 2012 in Developmental Cell, raises the hope that a simple genetic screening test for Nkx2.5 mutations can be developed that will alert parents that their developing child may be missing the organ, which could then be confirmed with a diagnostic scan. "The great news is that with the appropriate preventive antibiotic treatment these children will not succumb to fatal infections. This test could potentially save lives," says the study's lead investigator, Dr. Licia Selleri, an associate professor in the Department of Cell and Developmental Biology at Weill Cornell Medical College. Because defense against infections depends, in part, on the spleen, children known to be born without the organ require treatment with a regimen of antibiotic therapy throughout their lives. But most diagnoses of this condition, congenital asplenia, are made during an autopsy after a child dies, suddenly and unexpectedly, from a rapidly lethal infection, usually from bacteria that causes pneumonia or meningitis, Dr. Selleri says. "For those reasons, we believe this condition is not quite as rare as believed. Not every child who dies from an infection is given an autopsy." Patients with congenital asplenia usually lack a spleen as the sole abnormality, but sometimes have abnormalities of the heart and blood vessels.

Extra Gene Drove Instant Leap in Human Brain Evolution

A partial, duplicated copy of a gene appears to be responsible for the critical features of the human brain that distinguish us from our closest primate kin. The momentous gene duplication event occurred about two or three million years ago, at a critical transition in the evolution of the human lineage, according to a pair of studies published on May 3, 2012 in Cell. The studies are the first to explore the evolutionary history and function of any uniquely human gene duplicate. These "extra" genes are of special interest as they provide likely sources of raw material for adaptive evolutionary change. Until now, studying them has been a technical challenge because they are nearly indistinguishable from each other. "There are approximately 30 genes that were selectively duplicated in humans," said Dr. Franck Polleux, an expert in brain development at The Scripps Research Institute. "These are some of our most recent genomic innovations." Intriguingly, many of these genes appear to play some role in the developing brain. In two independent studies, Dr. Polleux and Dr. Evan Eichler, a genome scientist at the University of Washington, focused their expertise and attention on one of the genes known as SRGAP2. This gene has, in fact, been duplicated at least twice during the course of human evolution, first about 3.5 million years ago and then again about 2.5 million years ago. The new work shows that the second and relatively recent duplication event produced only a partial copy of the gene. This copy acts at exactly the same time and place as the original, allowing it to interact with and block the ancestral gene's function. "This innovation couldn't have happened without that incomplete duplication," Dr. Eichler said.

Beehive Extract Shows Potential As Prostate Cancer Treatment

An over-the-counter natural remedy derived from honeybee hives arrests the growth of prostate cancer cells and tumors in mice, according to a new paper from researchers at the University of Chicago Medicine. Caffeic acid phenethyl ester, or CAPE, is a compound isolated from honeybee hive propolis, the resin used by bees to patch up holes in hives. Propolis has been used for centuries as a natural remedy for conditions ranging from sore throats and allergies to burns and cancer. But the compound has not gained acceptance in the clinic due to scientific questions about its effect on cells. In a paper published in the May 1, 2012 issue of Cancer Prevention Research, researchers combined traditional cancer research methods with cutting-edge proteomics to find that CAPE arrests early-stage prostate cancer by shutting down the tumor cells' system for detecting sources of nutrition. "If you feed CAPE to mice daily, their tumors will stop growing. After several weeks, if you stop the treatment, the tumors will begin to grow again at their original pace," said Richard B. Jones, Ph.D., assistant professor in the Ben May Department for Cancer Research and Institute for Genomics and Systems Biology and senior author of the study. "So it doesn't kill the cancer, but it basically will indefinitely stop prostate cancer proliferation." Natural remedies isolated from plant and animal products are often marketed as cure-alls for a variety of maladies, usually based on vague antioxidant and anti-inflammatory claims. While substances such as ginseng or green tea have been occasionally tested in laboratories for their medicinal properties, scientific evidence is commonly lacking on the full biological effects of these over-the-counter compounds. "It's only recently that people have examined the mechanism by which some of these herbal remedies work," Dr. Jones said.