March 13, 2006, 10:06 PM CT

A Woman With Amazing Memory

Scientists at UC Irvine have identified the first known case of a new memory syndrome - a woman with the ability to perfectly and instantly recall details of her past. Her case is the first of its kind to be recorded and chronicled in scientific literature and could open new avenues of research in the study of learning and memory.

Scientists Elizabeth Parker, Larry Cahill and James L. McGaugh spent more than five years studying the case of "AJ," a 40-year-old woman with incredibly strong memories of her personal past. Given a date, AJ can recall with astonishing accuracy what she was doing on that date and what day of the week it fell on. Because her case is the first one of its kind, the scientists have proposed a name for her syndrome - hyperthymestic syndrome, based on the Greek word thymesis for "remembering" and hyper, meaning "more than normal".

Their findings appear in the current issue of the journal Neurocase.

AJ first wrote McGaugh with the details of her extraordinary ability in 2000. She wrote that she "can take a date, between 1974 and today, and tell you what day it falls on, what I was doing that day and if anything of importance occurred on that day." She had been called "the human calendar" for years by her friends and acquaintances.........

Posted by: Daniel      Permalink         Source

March 12, 2006, 9:22 PM CT

Computer Suggests New HIV Drug Target

For more than a year, scientists watched patiently as a few computer-simulated HIV protease molecules squirmed into more than 15,000 slightly different shapes. In real time, this contortion takes only a fraction of a second. In the end, however, this suspended animation paid off, as the simulations uncovered a potential new drug target to fight drug-resistant AIDS.

Howard Hughes Medical Institute (HHMI) researchers made the discovery while studying how one rare strain of HIV can evade a usually prescribed class of drugs used to treat the virus that causes AIDS. The strain of HIV contained mutations that are often seen after failure of therapy with protease inhibitors, drugs that block the action of the enzyme protease and prevent the virus from making mature, infective copies of itself. When protease inhibitors fail -- as they often do with a fast-mutating virus like HIV -- new drug targets become vital.

"Recognizing these variations in conformation -- the three-dimensional arrangement of the amino acids that make up a protein -- is the first step in identifying a new drug target," said Alex Perryman, first author of the study published early online in the journal Biopolymers on February 28, 2006.

Perryman did the research when he was an HHMI predoctoral fellow in the lab of Andrew McCammon, an HHMI investigator in the Biomedical Sciences program at the University of California, San Diego. Perryman is now an Amgen postdoctoral fellow in the lab of Stephen Mayo, an HHMI investigator at the California Institute of Technology.........

Posted by: Mark      Permalink         Source

March 8, 2006, 9:39 PM CT

Pills To Lower LDL Cholesterol

A pill containing plant substances called sterols can help lower cholesterol, as per scientists at Washington University School of Medicine in St. Louis.

The scientists studied patients who already were eating a heart-healthy diet and taking statin drugs to control cholesterol. The addition of plant sterols helped further lower total cholesterol and contributed to a nearly 10 percent reduction in low-density lipoprotein (LDL) cholesterol, the so-called "bad" cholesterol. Results of the study were reported in the American Journal of Cardiology.

The National Cholesterol Education Program recommends that those with elevated cholesterol eat foods containing plant sterols as a way to lower cardiovascular risk, but a number of sterol-containing foods are inconvenient for some patients.

Structurally similar to cholesterol, plant sterols can reduce the absorption of cholesterol in the gut by competing with cholesterol to get absorbed and transported into the body. When consumed in the diet, sterols are known to lower cholesterol levels, but sterols are not readily absorbed in the intestine unless they have been dissolved in something that the intestine can easily absorb. Because sterols are not water-soluble, past strategies have involved dissolving them in fat.........

Posted by: Daniel      Permalink         Source

March 7, 2006, 8:19 PM CT

Liquid crystals and embryonic stem cells

Liquid crystals, the same phase-shifting materials used to display information on cell phones, monitors and other electronic equipment, can also be used to report in real time on the differentiation of embryonic stem cells.

Differentiation is the process by which embryonic stem cells gradually turn into function-specific types of adult cells or so-called "cell lineages," including skin, heart or brain cells.

The main challenge facing stem cell research is that of guiding differentiation along these well-defined, controlled lineages. Stem cells grown in the laboratory tend to differentiate in an uncontrolled manner, resulting in a mixture of cells of little medical use.

Now, UW-Madison scientists at the NSF-funded Materials Research Science and Engineering Center (MRSEC) have shown that by straining mechanically the cells as they grow, it is possible to reduce significantly and almost eliminate the uncontrolled differentiation of stem cells.

In an article in the recent issue of Advanced Functional Materials, the team reports on a liquid crystal-based cell culture system that promises new ways of achieving real-time control over interactions between synthetic materials and human embryonic stem cells, including the possibility of straining embryonic stem cells as they grow.........

Posted by: Scott      Permalink         Source

March 7, 2006, 8:12 PM CT

A Database For The Microbes

Scientists at the Virginia Bioinformatics Institute at Virginia Tech have launched a publicly-available microbial database to host a range of microbial genome sequences.

The VBI Microbial Database (VMD), which is described in a recent article published in Nucleic Acids Research (Vol.34, D379-D381), contains genome sequence and annotation data for the plant pathogens Phytophthora sojae and Phytophthora ramorum. The purpose of the database is to make the recently completed genome sequences of these pathogens as well as powerful analytical tools widely available to scientists in one integrated resource. The work described in the paper was completed by Brett Tyler, VBI research professor and professor of plant pathology, physiology, and weed science at Virginia Tech, and VBI scientists Sucheta Tripathy, Varun Pandey, Bing Fang, and Fidel Salas.

VMD is an integrated resource that includes community annotation features, toolkits, and resources to perform complex queries of biological information. The project's scientists created a browser, which makes it easy for users to view the genome sequence data and connect to detailed annotation pages for each sequence. The community annotation interface is available for registered members to add or edit annotations.

The database will be expanded in 2006 to include genome sequences for the fungal pathogen Alternaria brassicicola and the oomycete pathogen Hyaloperonospora parasitica, both of which can infect the model plant Arabidopsis. In addition, support for proteomic and microarray data will be added, which will be linked to the functional genomic data and the genome sequences.........

Posted by: Scott      Permalink         Source

March 7, 2006, 0:21 AM CT

Separate Brain Mechanisms For Ambiguous And Risky Choices

Distinct regions of the human brain are activated when people are faced with ambiguous choices versus choices involving only risk, Duke University Medical Center scientists have discovered.

The researchers found that they could predict activation of different brain areas, based on how averse study participants were toward either risk or ambiguity. The finding confirms what economists have long debated -- that different attitudes toward perceived risk and ambiguity in decision-making situations may reflect a basic distinction in brain function, the scientists said. Such fundamental knowledge of neural functioning will contribute to an understanding of why people make risky choices, and how such risk-taking can become pathological, as in addiction or compulsive gambling, they added.

Their study appears in the March 2, 2006 issue of Neuron. The research was supported by the National Institute of Mental Health, the National Institute of Neurological Disorders and Stroke and Duke.

"We were able to see individual differences in brain activation depending on the person's preferences or aversions to risk and ambiguity," said Scott Huettel, Ph.D., lead author and a neuroscientist with the Brain Imaging and Analysis Center at Duke University. "People who preferred ambiguity had increased activation in the prefrontal cortex, and people who preferred risk had increased activation in the parietal cortex. This opens up the possibility that there are specific neural mechanisms for different forms of economic decision making, which is a very exciting idea."........

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March 4, 2006, 9:16 PM CT

Call From The Dying Fat Cells

Researchers have known that immune cells are responsible for most of the inflammatory chemicals that are released within fat tissue--but they haven't known why. Now a study published by Agricultural Research Service-funded researchers shows that white blood cells, called macrophages, appear to rush to dead fat cells to mop them up, the same way they surround a splinter lodged in skin.

The study, authored by doctor Andrew Greenberg, cell biologist Martin Obin and his colleagues, was reported in the Journal of Lipid Research. Both researchers are with the Obesity and Metabolism Laboratory at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University in Boston, Mass.

The scientists found that as people gain weight, fat cells gradually enlarge and eventually break down and die. When obesity continues over a period of time, a cycle occurs in which new fat cells form to store the added fat, then peak in size and finally die. The study showed that more than 90 percent of the macrophages in the fatty tissue of obese mice and humans are located around these dead fat cells. In addition, as the fat cells get bigger, the prevalence of macrophages increases proportionally.........

Posted by: Scott      Permalink     

March 3, 2006, 6:43 AM CT

Vitamin E Sends Mixed Messages

One of the most powerful antioxidants is truly a double-edged sword, say scientists at Ohio State University who studied how two forms of vitamin E act once they are inside animal cells.

In the past couple of decades, a slough of studies has looked at the benefits of vitamin E and other antioxidants. While a considerable amount of this research touts the advantages of consuming antioxidants, some of the studies have observed that in certain cases, antioxidants, including vitamin E, may actually increase the potential for developing heart disease, cancer and a host of other health problems.

This study provides clues as to why this could happen, say Jiyan Ma, an assistant professor of molecular and cellular biochemistry, and his colleague David Cornwell, an emeritus professor of molecular and cellular biochemistry, both at Ohio State.

The two men led a study that compared how the two most common forms of vitamin E -- one is found primarily in plants like corn and soybeans, while the other is found in olive oil, almonds, sunflower seeds and mustard greens - affect the health of animal cells. The main difference between the two forms is a slight variation in their chemical structures.

In laboratory experiments, the kind of vitamin E found in corn and soybean oil, gamma-tocopherol, ultimately destroyed animal cells. But the other form of vitamin E, alpha-tocopherol, did not. (Tocopherol is the scientific name for vitamin E.).........

Posted by: Janet      Permalink         Source

February 28, 2006, 11:06 PM CT

A Better Way To Deliver Gene Therapy

While gene treatment continues to be a promising area of medicine, a major drawback of this kind of therapy can spell failure for a number of patients enrolled in gene treatment clinical trials: Most people's immune systems may destroy the viral carrier that is most often used to deliver healthy genes into sick cells.

A new study explains that researchers may have found a way around this problem.

Scientists used a laboratory technique called polymerase chain reaction (PCR) to alter genetic sequences of the outer coating, or capsid, of adeno-associated virus (AAV). AAV is a normally innocuous virus that is often used to deliver healthy genes to diseased tissues.

"We were able to make random changes throughout the entire genetic sequence of the AAV capsid," said Brian Kaspar, a co-author of study and an assistant professor of pediatrics at Ohio State University.

"And by doing that we generated more than a million different variations of this capsid, including mutations that the human immune system hopefully won't recognize and therefore shouldn't react against".

The scientists describe their technique in the current issue of the journal Nature Biotechnology.

In gene treatment, physicians insert healthy genes into a person who has an unhealthy form of those genes. The hope is that these new, good genes will correct the problem. Viruses are currently the most common vehicle used to deliver genes into the body.........

Posted by: Scott      Permalink         Source

February 27, 2006, 9:45 PM CT

Across the Resolution Gap

One out of a thousand children in the United States is born deaf; ten percent of all people living in industrialized nations suffer from severe hearing loss - 30 million in the U.S. alone. These are pressing clinical reasons to learn just how hearing works and why it fails.

"Hearing in humans is a remarkable faculty," says Manfred Auer of Berkeley Lab's Life Sciences Division. "It works over six orders of magnitude, from a whisper to the roar of a jet engine. If it were just a little more sensitive, we'd be able to hear the atoms colliding with our eardrums - in other words, our hearing is about as sensitive as we can stand without going crazy."

Hearing is also remarkable for its ability to adapt to constant loud noise yet still manage to pick out barely distinguishable sounds, "like being able to follow a single conversation across the room at a cocktail party, or hearing someone shout at you over the noise of a rock band," says Auer.

And humans can pinpoint the source of a sound to within less than a degree: one ear hears the sound slightly before the other, and the brain calculates the direction from the offset. But the difference in arrival times is less than a millionth of a second, a thousand times faster than most biochemical processes; thus hearing must depend on direct mechanical detection of sounds instantly translated into nerve signals.........

Posted by: Sue      Permalink