August 7, 2006, 11:58 PM CT

Best Memorization Strategies

Exploring exactly why some individuals' memory skills are better than others has led scientists at Washington University in St. Louis to study the brain basis of learning strategies that healthy young adults select to help them memorize a series of objects. Using functional magnetic resonance imaging (fMRI), the scientists uncovered brain regions specifically correlated with the diverse strategies that subjects adopt.

Brenda Kirchhoff, research associate in psychology in the University's School of Arts and Sciences, conducted this study in the then-Washington University lab of Randy L. Buckner, now a professor of psychology at Harvard University and investigator at the Howard Hughes Medical Institute. Their findings have been reported in the July 20, 2006, issue of Neuron. (Kirchhoff is the article's first author and Buckner is senior author.).

"Randy and I were interested in exploring individual differences in memory - why some people are better at learning new information than others," said Kirchhoff. "Our main goal was to determine the learning strategies that people use and their relationship to memory performance. Secondly, we wanted to know if individual differences in learning strategies were linked to individual differences in brain activity".

What they found was that test subjects used two main self-selected strategies to learn new information. Use of the strategies was linked to better memory performance. Furthermore, individual differences in learning strategies could be correlated with MRI-detected biological activity in distinct brain regions.........

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August 7, 2006, 11:47 PM CT

Use The Abdomen To Deliver Oxygen

Researchers at the University of Pennsylvania School of Medicine have helped develop a technique in animal models for using the abdominal cavity to exchange gas, supplementing the function normally performed by the lungs. The goal is to provide a way to support patients who are on a mechanical ventilator, suffering from reversible lung failure, but who need extra time and support to heal -- beyond what a ventilator can provide -- in order to survive. The findings are in the recent issue of Chest, the journal of the American College of Chest Physicians.

"This is an alternate, novel way to deliver oxygen to the body that does not attempt to wring more function out of an already injured lung, by using ventilator settings that can actually exacerbate the underlying lung injury. The only other alternates that can 'rest' the lung involve variations of bypass machine technology, all of which require anticoagulation," explains Joseph Friedberg, MD, Associate Professor of Surgery and principal investigator of this study. "The ability to rest the lungs and provide supplemental oxygen with a technique that appears nontoxic and does not require anticoagulants could have huge implications some day for patients suffering from potentially reversible pulmonary failure from such diseases as: anthrax, bird flu, SARS, trauma, ARDS, pulmonary embolism, pneumonia and others. Sometimes patients have a condition in which they might have a chance to recover if they could survive the most severe phase of their disease".........

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August 6, 2006, 0:01 AM CT

Broad Talk Illuminates Genetics

For decades, scientists have been teasing out the secrets of the human genome, hoping to learn more about what makes the body function and why things sometimes go wrong.

Now, scientists are on the brink of identifying genes that play a major role in a variety of diseases, thanks to recent rapid advances in DNA sequencing technology, according to Dr. David Altshuler, director of the program in medical and population genetics at the Broad Institute of MIT and Harvard.

Altshuler talked about "expectations for improved therapies in the era of genomic medicine" at the final installment of the "Midsummer Nights' Science" lecture series held at the Broad Institute on Aug. 1.

Researchers at the Broad and around the world are using new sequencing technology to look for genes that are linked to the development of diseases such as diabetes, multiple sclerosis, lupus, bipolar disorder and autism, among many others.

The new research builds on the 2003 completion of the human genome sequence, which showed that while most humans share the vast majority of their genetic sequence (about 99.9 percent), variations known as single nucleotide polymorphisms, or SNPs, occur within the other.1 percent of the genome. Those variations are what make each individual unique.........

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August 4, 2006, 0:06 AM CT

Links between DNA damage and breast cancer

Scientists from the Pacific Northwest Research Institute (PNRI) and the National Institute of Standards and Technology (NIST) have uncovered a pattern of DNA damage in connective tissues in the human breast that could shed light on the early stages of breast cancer and possibly serve as an early warning of a heightened risk of cancer.

In the United States, breast cancer is the second leading cause of cancer-related death in women. Breast cancer detection and treatment generally target epithelial cells, the primary locus of breast cancers, but in recent years evidence has accumulated that genetic mutations that develop into cancer may occur initially in a deeper layer of breast tissue, called the stroma. Genetic changes in this connective tissue that supports the breast's network of glands and ducts have been reported to precede the cancerous conversion of tumor cells, but the actual role of stromal cells in the early stages of breast cancer initiation and progression is not well understood.

In two recent papers*, the PNRI/NIST team explored the occurrence of damage to stromal DNA caused by free radicals and other oxidants. NIST scientists used a high-precision chemical analysis technique (liquid chromatography/mass spectrometry with isotope dilution) to identify specific DNA lesions, while the PNRI team used a spectroscopic technique (Fourier transform-infrared spectroscopy) to reveal subtle conformational changes to DNA base and backbone structures. Such alterations to the molecular structure can change or disrupt gene expression.........

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August 2, 2006, 11:41 PM CT

CT Images Faster Than Traditional Scanners

Scientists at the University of North Carolina at Chapel Hill have developed a new method to create computed tomography (CT) images using carbon nanotube x-rays that works much faster than traditional scanners and uses less peak power.

The work is another step toward developing scanners for medical imaging and homeland security that are smaller, faster, and less expensive to operate, said Dr. Otto Zhou, Lyle Jones Distinguished Professor of Materials Science, in the curriculum in applied and materials sciences and the department of physics and astronomy, both in UNC's College of Arts and Sciences.

"The current CT scanners take images sequentially, which is slow and inefficient. Using the nanotube x-ray technology, we show in this paper the feasibility of multiplexing - taking multiple images at the same time," Zhou said.

Carbon nanotubes, made of layers of carbon atoms, can be as small as one nanometer - one billionth of a meter - in diameter. The UNC team uses them in this work because they can emit electrons without high heat.

The new development is published in the current edition of the journal Applied Physics Letters. The lead author of the paper is Dr. Jian Zhang, a postdoctoral research associate in the UNC School of Medicine's department of radiation oncology. In addition to Zhou, other authors - all from UNC - are Dr. Sha Chang, associate professor of radiation oncology; doctoral candidate Guan Yang and Dr. Jianping Lu, professor of condensed matter physics, both of the department of physics and astronomy; and Dr. Yueh Lee, an intern at the medical school and an adjunct assistant professor in physics and astronomy.........

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August 1, 2006, 11:43 PM CT

Evolution At The Tips Of Chromosomes

In terms of their telomeres, mice are more complicated than humans. That's the finding from a recent Rockefeller University study, which shows that mice have two proteins working together to do the job of a single protein in human cells. The findings, published recently in Cell, suggest that the protein complex that protects chromosome ends may have evolved far more rapidly than previously believed.

Acting as caps on the ends of each chromosome, telomeres are composed of repetitive DNA and shelterin, a protective protein complex protects. Titia de Lange's lab has identified many of the components of shelterin and studies how its components work together to ensure that chromosome ends are not recognized as DNA breaks.

Previous work from the de Lange lab showed that TRF2, a shelterin protein that binds to the duplex part of the telomere, is crucial for telomere protection. Without TRF2, telomeres activate a DNA damage signal and are repaired by the same pathways that act on DNA breaks. TRF2 brings a second shelterin protein, POT1, to the telomeres. Because POT1 binds to single-stranded telomeric DNA present at the very end of the chromosomes, the de Lange lab asked how POT1 contributes to the protection of telomeres.

"We had previously removed TRF2 from mouse cells and seen many dramatic phenotypes," says de Lange, "all of the telomeres ligate together; there is a massive DNA damage response and the cells basically die. We argued that if the function of TRF2 was to bring POT1 to the DNA, then we should observe the same phenotype if we removed POT1".........

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August 1, 2006, 11:05 PM CT

Emphysema Patients Might Benefit From Surgery

The latest results from the landmark National Emphysema Treatment Trial (NETT) confirm and extend earlier findings that selected patients with advanced emphysema predominately in the upper area of the lung may benefit from surgery and the benefits are still apparent with two more years of follow-up. The newly published findings from the largest study of bilateral lung volume reduction surgery (LVRS) to treat severe emphysema also confirm that patients with upper-lobe emphysema and poor exercise capacity before surgery are more likely to have improved survival compared to similar patients treated with medical therapy without surgery. Surgery might also provide some symptom relief in patients with emphysema in the upper lung area but who had good exercise capacity prior to surgery; however, survival rates did not improve in this group.

NETT researchers describe the effects of LVRS after following 1218 patients for an average of 4.3 years, two years longer than the primary results reported in 2003. The earlier findings led to Medicare coverage of LVRS for patients meeting criteria based on the study results. NETT began in 1996 as a cooperative effort between the National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health and the Centers for Medicare & Medicaid Services. Both are agencies of the U.S. Department of Health and Human Services.........

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August 1, 2006, 7:03 AM CT

Reduce Prostate Cancer Growth Rate

UCLA scientists observed that altering the fatty acid ratio found in the typical Western diet to include more omega-3 fatty acids and decrease the amount of omega-6 fatty acids may reduce prostate cancer tumor growth rates and PSA levels.

Reported in the Aug. 1 issue of the journal Clinical Cancer Research, this initial animal-model study is one of the first to show the impact of diet on lowering an inflammatory response known to promote prostate cancer tumor progression and could lead to new therapy approaches.

The omega-6 fatty acids contained in corn, safflower oils and red meats are the predominant polyunsaturated fatty acids in the Western diet. The healthier marine omega-3 fatty acids are found in cold-water fish like salmon, tuna and sardines.

"Corn oil is the backbone of the American diet. We consume up to 20 times more omega-6 fatty acids in our diet in comparison to omega-3 acids," said principal investigator Dr. William Aronson, a professor in the department of urology at the David Geffen School of Medicine at UCLA and a researcher with UCLA's Jonsson Cancer Center. "This study strongly suggests that eating a healthier ratio of these two types of fatty acids may make a difference in reducing prostate cancer growth, but studies need to be conducted in humans before any clinical recommendations can be made".........

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August 1, 2006, 6:44 AM CT

human cytomegalovirus vaccine outlined

Philadelphia -- Each year, about 40,000 children are born infected with human cytomegalovirus, or CMV, and about 8,000 of these children suffer permanent disabilities due to the virus almost one an hour. These disabilities can include hearing loss, vision loss, mental disability, a lack of coordination, and seizures. According to the Centers for Disease Control and Prevention, CMV is as common a cause of serious disability as Down syndrome, fetal alcohol syndrome, or neural tube defects.

Because of the dangers posed by the virus to infants, the Institute of Medicine has declared that development of a CMV vaccine should be one of the highest priorities for vaccine makers. Now, in a new study in the August 1 issue of The Journal of Virology, researchers at The Wistar Institute outline an innovative approach that could be used to create such a vaccine.

The Wistar scientists began with the observation that mice harbor a species-specific form of CMV that is unable to sustain an infection in humans and is completely harmless to them. They then asked whether, using recombinant technologies, there might not be a way to shift the mouse-specific virus closer to the human-specific virus to generate a version of the virus able to elicit a protective immune response but not a dangerous infection in humans.........

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July 31, 2006, 10:33 PM CT

An Eye-opening Look At Anesthesia

Raise your hand if you are more afraid of the prospect of general anesthesia than of surgery itself. If you raised your hand, you are not alone, as per the newest faculty member at the Harvard-MIT Division of Health Sciences and Technology (HST).

Dr. Emery N. Brown, who explores what happens to the brain during anesthesia, began a dual appointment as professor of health sciences and technology and professor of computational neuroscience in the Department of Brain and Cognitive Sciences (BCS) at MIT in October 2005.

"Anesthesia has taken on a mythical quality; it's not perceived as a neuro-physiological phenomenon," he said.

He describes the motivation behind his current research focus: "For a number of years, I was practicing anesthesiology, learning clinical skills in order to take care of patients, not thinking about how anesthesia affects patients. Then 10 years ago, when HST alum Dr. Greg Koski was the head of human studies at MGH, he said, 'It would be interesting to see an image, to see what happens when someone is under anesthesia.'" Brown was hooked.

"We say we induce anesthesia and then 'wake up' the patient," Brown said. "But in French the patient is reanime, or brought back to life. We haven't yet begun to think precisely about what we do, however. Anesthesia is not like sleep. It's not the same process".........

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