October 22, 2006, 11:03 PM CT

Novel Studies Of Human Infection

A new type of laboratory mouse developed at UT Southwestern Medical Center can fight certain infections the same way humans do, making the rodents very useful for novel studies of human-pathogen interaction and developing disease therapies.

Normal mice are not susceptible to human-specific viruses, such as Epstein Barr virus and HIV, making it hard to study and craft drugs to target the viruses. Epstein Barr is a virus that causes mononucleosis.

So UT Southwestern researchers, working with University of Minnesota collaborators, generated human-mice "chimeras" mice implanted with human tissues and human stem cells that developed fully functional human immune systems and infection-fighting cells, such as T cells, throughout their bodies, according to a study published online today in Nature Medicine

The T cells in the mice even mounted a potent immune response to toxic shock syndrome and infection by Epstein Barr.

"These human-mice 'chimeras' are susceptible to a variety of human-specific viruses that couldn't be easily studied in the past, giving scientists a new way to study, develop and implement novel vaccines and therapeutics to fight human disease like cancer and AIDS," said Dr. J. Victor Garcia, professor of internal medicine at UT Southwestern and the study's senior author.........

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October 19, 2006, 9:51 PM CT

Malaria in the Middle East

Malaria is not usually thought of as a major disease in the Middle East, but a study from Yemen in this week's BMJ reveals worryingly high levels of severe malaria in children.

In fact, the figures show that as many as 4 out of 10 children attending hospital with severe illness could be affected during the peak season. This is comparable to many areas of Africa.

Researchers identified over 2,000 children aged 6 months to 10 years who were admitted to two public hospitals with suspected severe malaria. Malaria was confirmed in 1,332 children, 808 of whom had severe malaria.

The proportion of admissions varied according to the season, from 1% between July and September to 40% in February and March. Twenty six children died in hospital. Most deaths were in children with a neurological presentation, and more girls died than boys.

Severe malaria puts a high burden on health services in Yemen, say the authors. Malaria control should be a priority and lesson should be learnt from other areas of highly seasonal malaria.........

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October 12, 2006, 4:51 AM CT

Antioxidants Fish Oil And AMD

The National Institutes of Health (NIH) announces a nationwide study to see if a modified combination of vitamins, minerals, and fish oil can further slow the progression of vision loss from AMD, the leading cause of vision loss in the United States for people over age 60. This new study, called the Age-Related Eye Disease Study 2 (AREDS2), will build upon results from the earlier Age-Related Eye Disease Study (AREDS). The original study results were released five years ago today. The study observed that high-dose antioxidant vitamins and minerals (vitamins C and E, beta-carotene, zinc, and copper), taken by mouth, reduced the risk of progression to advanced AMD by 25 percent, and the risk of moderate vision loss by 19 percent.

AREDS2 will refine the findings of the original study by adding lutein and zeaxanthin (plant-derived yellow pigments that accumulate in the macula, the small area responsible for central vision near the center of the retina) and the omega-3 fatty acids DHA and EPA (derived from fish and vegetable oils) to the study formulation. The main study objective is to determine if these nutrients will decrease a person's risk of progression to advanced AMD, which often leads to vision loss. Prior findings based on observation have suggested these nutrients may protect vision.........

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October 11, 2006, 4:43 AM CT

Timing Of Spinal Surgery

When it comes to a devastating spinal injury, says spine surgeon Alexander Vaccaro, M.D., timing might be nearly everything. It's also a topic of great debate and discussion among orthopaedic surgeons.

Dr. Vaccaro, professor of orthopaedic surgery and neurological surgery at Jefferson Medical College of Thomas Jefferson University in Philadelphia and the Rothman Institute at Thomas Jefferson University Hospital and colleagues are trying to answer a very difficult and controversial question: Should surgeons operate immediately, within hours of the severe spinal injury, to try to limit the damage to the spinal cord and surrounding tissues, as a number of surgeons believe? Or won't it make a difference in how a patient ultimately fares, as others, citing their experiences, say?.

Dr. Vaccaro, in conjunction with Michael G. Fehlings, M.D., at Toronto Western Hospital, is spearheading a multicenter trial called STASCIS, which looks at timing of surgery, the timing of spinal reduction and a prospective evaluation of how patients do.

STASCIS is an acronym for the Surgical Treatment of Acute Spinal Cord Injury Study. Begun in 2003, STASCIS is both an observational and prospective randomized study aimed at determining if patients with spinal cord injury will benefit from early therapy to reduce pressure on the spinal cord.........

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October 9, 2006, 9:22 PM CT

mammalian 'disorderly' proteins

Investigators at St. Jude Children's Research Hospital turned up the heat on "disorderly" proteins and confirmed that most of these unruly molecules perform critical functions in the cell. The St. Jude team completed the first large-scale collection, investigation and classification of these so-called intrinsically unstructured proteins (IUPs), a large group of molecules that play vital roles in the daily activities of cells.

The new technique for collecting and identifying IUPs is important because although scientists have been aware of the existence of flexible proteins for many years, they have only recently realized that these molecules play major biological roles in the cell, according to Richard Kriwacki, Ph.D., an associate member of the St. Jude Department of Structural Biology. Moreover, he said, previous work by other researchers suggested that a large proportion of IUPs in mammalian cells play key roles in transmitting signals and coordinating biochemical and genetic activities that keep the cell alive and functioning. Kriwacki is senior author of a report on this work that appears in the prepublication online issue of Journal of Proteome Research.

"Until now there was no way to separate IUPs in large numbers from the more structured proteins and confirm their roles in the cell," Kriwacki said. "Our new technique selectively concentrates the IUPs that are involved in regulating functions in the cell and transmitting signals within them".........

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October 6, 2006, 4:48 AM CT

Babies With Persistent Pulmonary Hypertension

If he can figure out which babies will be born unable to breathe properly, Dr. Stephen M. Black thinks he can help change that.

"When these kids are born, you have a short amount of time to intervene or you get brain damage," says Dr. Black, cell and molecular physiologist at the Medical College of Georgia Vascular Biology Center.

Unfortunately, persistent pulmonary hypertension comes as a surprise in full-term babies, says Dr. Jatinder J.S. Bhatia, chief of the MCG Section of Neonatology. The pregnancy seems uneventful until the hours following birth when breathing trouble requires rapid transport to a neonatal intensive care unit.

"What happens in utero is that all your gas exchange is through the placenta, so there is only about 8 percent of cardiac output actually going through the lungs," says Dr. Black. "When you are born, obviously there is 100 cardiac output and you need to breathe".

When babies can't breathe well, physicians quickly determine whether the primary problem is the heart or lungs, Dr. Bhatia says. When it's the lungs, babies first get oxygen therapy and possibly mechanical ventilation. If it is pulmonary hypertension, the powerful vasodilator, nitric oxide, is used to reduce high pressures in the pulmonary circuit and allow the transition to a normal circulation. Neonatologists also have begun using the popular erectile dysfunction drug, Viagra, to dilate tiny pulmonary vessels.........

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October 3, 2006, 9:59 PM CT

Uncoveing Roots Of DNA Secrets

DNA's simple and elegant structure - the "twisted ladder," with sugar-phosphate chains making up the "rails" and oxygen- and nitrogen-containing chemical "rungs" tenuously uniting the two halves - seems to be the work of an accomplished sculptor.

Yet the graceful, sinuous profile of the DNA double helix is the result of random chemical reactions in a simmering, primordial stew.

Just how nature arrived at this molecule and its sister molecule, RNA, remains one of the greatest - and potentially unsolvable - scientific mysteries.

But Vanderbilt biochemist Martin Egli, Ph.D., isn't content to simply study these molecules as they are. He wants to know why they are the way they are.

"These molecules are the result of evolution," said Egli, professor of Biochemistry. "Somehow they have been shaped and optimized for a particular purpose".

"For a chemist, it makes sense to analyze the origin of these molecules".

One particular curiosity: how did DNA and RNA come to incorporate five-carbon sugars into their "backbone" when six-carbon sugars, like glucose, may have been more common? Egli has been searching for the answer to that question for the past 13 years.

Recently, Egli and his colleagues solved a structure that divulges DNA's "sweet" secret. In a recent issue of the Journal of the American Chemical Society, Egli and his colleagues report the X-ray crystal structure of homo-DNA, an artificial analog of DNA in which the usual five-carbon sugar has been replaced with a six-carbon sugar.........

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October 1, 2006, 8:16 PM CT

What Drives Your Taste Buds

What are the genes that are crucial to the taste bud development?

The gene, SOX2, stimulates stem cells on the surface of the embryonic tongue and in the back of the mouth to transform into taste buds, according to the researchers. Stem cells are immature cells that can develop into several different cell types depending on what biochemical instructions they receive.

"Not only did we find that SOX2 is crucial for the development of taste buds, but we showed that the amount of SOX2 is just as important," said Brigid Hogan, Ph.D., chair of the Duke University Medical Center Department of Cell Biology and senior member of the research team. "If there isn't enough SOX2 present, or if there is too much, the stem cells will not turn into taste buds".

The researchers made their discovery in mice, but they believe the same process occurs in humans.

According to the researchers, the findings will help scientists better understand how the behavior of certain stem cells is controlled. The SOX2 gene is already known to be crucial in controlling whether embryonic stem cells remain undifferentiated and whether stem cells in the brain, eye and inner ear differentiate into specialized nerve cells.

Taste bud cells, much like skin cells, continually slough off and are replaced by new ones. So the new findings not only provide insights into the interactions between SOX2 and tongue stem cells during embryonic development, but also into how stem cells continue to operate in adults, the researchers said.........

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October 1, 2006, 7:47 PM CT

Treatment For Sleeplessness In The Elderly

Insomnia or lack of sleep is a common problem among elderly people. It is a more widespread problem than we recognize. Now researchers are suggesting that a brief behavioral treatment for insomnia (BBT) could help those elderly individuals suffering from insomnia.

Brief behavioral treatment for insomnia (BBTI) appears to be a promising intervention for older adults who suffer from insomnia.

The study, conducted by Anne Germain, PhD, and colleagues of the University of Pittsburgh School of Medicine, focused on 17 older adults who were randomly assigned to receive BBTI, and 18 selected to receive an information-only control (IC) condition. All participants completed clinician-administered and self-report measures of sleep quality, as well as a sleep diary. Interventions were delivered in a single individual session with a booster session administered two weeks later. Postintervention assessments were completed after four weeks.

The results showed significant improvements in sleep measures and in daytime symptoms of anxiety and depression in 71 percent of those individuals who received BBTI, compared to 39 percent favorable response among IC participants. Furthermore, 53 percent of BBTI participants met criteria for remission, while 17 percent of those in the IC group met the same criteria.........

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September 28, 2006, 10:13 PM CT

Maps For Fighting Poverty

To increase awareness and promote usage of geographic information system applications in development strategies, the Center for International Earth Science Information Network and the World Bank have produced "Where the Poor Are: An Atlas of Poverty," a series of maps detailing spatially referenced data on hunger, child mortality, income poverty and other related indicators at the global, regional, national and local scales.

The maps included in "Where the Poor Are" show how advances in data collection and technology can be used to put poverty-related indicators into meaningful visual context. The book includes maps on the global and continental distribution of infant mortality and hunger, the distribution of resource inequality in five sub-Saharan countries, and poverty rates in Viet Nam, Nicaragua and Bolivia, to name just a few. As per Marc Levy, Associate Director for Science Applications at CIESIN, these maps and data sets help broaden the understanding of the relationship between poverty and geography--beyond the more common urban-rural framework. "The revolutionary advances in poverty mapping have made it possible to be precise about things we used to only generalize about," says Levy. "Connections between poverty and climatic conditions, soil fertility, exposure to natural disasters, access to transportation networks, and other important drivers, are beginning to come into sharp relief".........

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