February 10, 2010, 8:17 AM CT
Neuroimaging study may combat Alzheimer's
Gil Rabinovici, MD, assistant professor of neurology in the UCSF Memory and Aging Center
Researchers have determined that a new instrument known as PIB-PET is effective in detecting deposits of amyloid-beta protein plaques in the brains of living people, and that these deposits are predictive of who will develop Alzheimer's disease.
The finding, the result of a survey of more than 100 studies involving the instrument, including those by the scientists, confirms the sensitivity of the tool, still not commercially available. In clinical practice, amyloid deposits are detected only on autopsy.
The study also provides good evidence supporting the so-called "amyloid hypothesis" - the theory that accumulation of amyloid-beta protein plaques in the brain is central to the development of the disease. While significant evidence has supported this hypothesis, it has been questioned for two main reasons. First, amyloid deposits do not correlate with the severity of the disease, and are, in fact, found at autopsy in people who did not have clinical symptoms; and second, drugs targeting the plaques have shown disappointing results, even when the drugs were successful at substantially lowering plaque burden. Thus, the question of amyloid's role in the illness has remained.
"Our survey of PIB-PET studies, which looked cross-sectionally and longitudinally at people with normal cognitive performance, mild cognitive impairment and full-fledged Alzheimer's disease, showed that amyloid deposits can be detected in a significant proportion of cognitively normal elderly adults, and that their presence is linked to Alzheimer's-like brain atrophy and changes in brain activity," says co-author Gil Rabinovici, MD, assistant professor of neurology in the UCSF Memory and Aging Center.........
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February 10, 2010, 8:15 AM CT
When do you explore new things?
A sick or sad child might cling to mom's leg. But that same child fed, rested and generally content will happily toddle off to explore every nook and cranny of the known world. Or: You're chipper and you decide to check out the new restaurant across town. You're blue and you turn to comfort foods.
If you've seen or experienced these scenarios, you may not be surprised about the latest finding from an international team of social and cognitive psychology experts: A negative mood, it turns out, imparts a warm glow to the familiar. Happiness, conversely, makes novelty attractive (and can instead give the familiar a "blah" cast). But it is the first time the effect has been experimentally demonstrated in humans.
Led by University of California, San Diego psychology professor Piotr Winkielman, with Marieke de Vries, currently affiliated with the Leiden University Medical Center in the Netherlands, as first author on the paper, the study is published online in the journal Psychological Science
The findings, Winkielman said, not only contribute to understanding basic human psychology but also have numerous applications: To parenting and other interpersonal relationships and even in a number of of the "persuasion professions." In business, in marketing and advertising and in political campaigns, people would be well-advised to take note of the research. When companies introduce novel products, for example, they may want to do so in settings that encourage a happy, playful mood. A surgeon's office, meanwhile, Winkielman said, which people visit rarely and in stressful circumstances, should probably stay away from edgy dcor, opting instead for the comfy and familiar.........
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February 10, 2010, 8:12 AM CT
Depression and lack of concentration
A number of clinicians think that depression goes hand in hand with cognitive difficulties such as memory problems or difficulties concentrating and paying attention, but a recent review of nearly 20 years of literature conducted by scientists from UT Southwestern Medical Center has observed that depression does not always lead to such impairments.
"The relationship between cognition thinking, attention and memory and depression remains poorly understood from a neuroscientific standpoint," said Dr. Munro Cullum, chief of psychology at UT Southwestern and senior author of the review appearing in the recent issue of Neuropsychology
, a journal published by the American Psychological Association. "This paper represents an important review of the literature that challenges some of the clinical myths about the effects of depression on cognitive functioning".
Part of what contributes to the clinical lore is that difficulties in concentrating can be a symptom of depression, and this may masquerade as other cognitive problems such as variability in memory performance.
"The presentation of depression can vary between people," said Dr. Shawn McClintock, assistant professor of psychiatry at UT Southwestern and main author of the study. "A number of symptoms can be used to diagnose depression, so we tried to dissect and better understand how specific factors in depression might contribute to cognitive difficulties".........
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February 10, 2010, 8:02 AM CT
Racial gaps continue in heart disease
Racial gaps exist in women's heart-health awareness, women's knowledge of heart attack warning signs requires attention and nearly half of women report they would not call 9-1-1 if they were having heart attack symptoms, as per new research published in Circulation: Cardiovascular Quality and Outcomes, a journal of the American Heart Association.
Results of the study, commissioned by the American Heart Association, revealed that eventhough 60 percent of white women were aware of heart disease as the leading cause of death for women, less than half of African-American (43 percent), Hispanic (44 percent) and Asian (34 percent) women identified heart disease as the leading cause.
In addition, most women lacked knowledge of evidence-based therapies for preventing cardiovascular disease, and half of women ages 25-34 were unaware of heart disease as women's No. 1 killer, demonstrating the need for prevention education to avert death and disability from heart disease.
"The American Heart Association just announced its 2020 strategic goal: by 2020, to improve the cardiovascular health of all Americans by 20 percent while reducing deaths from cardiovascular diseases and stroke by 20 percent," said Lori Mosca, M.D., Ph.D, M.P.H., main author of the paper and Director of Preventive Cardiology at New York-Presbyterian Hospital in New York City. "Our study shows that these goals will be virtually impossible to achieve without first creating awareness among multicultural and younger women, educating women about the warning signs of heart attack and underscoring the importance of calling 9-1-1 immediately if they are experiencing heart attack symptoms".........
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February 9, 2010, 9:06 AM CT
Brain area responsible for fear of losing money
Neuroresearchers at the California Institute of Technology (Caltech) and their colleagues have tied the human aversion to losing money to a specific structure in the brainthe amygdala.
The finding, described in the latest online issue of the journal Proceedings of the National Academy of Sciences
(PNAS), offers insight into economic behavior, and also into the role of the brain's amygdalae, two almond-shaped clusters of tissue located in the medial temporal lobes. The amygdala registers rapid emotional reactions and is implicated in depression, anxiety, and autism.
The research team that made these findings consists of Benedetto de Martino, a Caltech visiting researcher from University College London and first author on the study; Colin Camerer, the Robert Kirby Professor of Behavioral Economics; and Ralph Adolphs, the Bren Professor of Psychology and Neuroscience and professor of biology.
The study involved an examination of two patients whose amygdalae had been destroyed due to a very rare genetic disease; those patients, along with individuals without amygdala damage, volunteered to participate in a simple "experimental economics task".
In the task, the subjects were asked whether or not they were willing to accept a variety of monetary gambles, each with a different possible gain or loss. For example, participants were asked whether they would take a gamble in which there was an equal probability they'd win $20 or lose $5 (a risk most people will choose to accept) and if they would take a 50/50 gamble to win $20 or lose $20 (a risk most people will not choose to accept). They were also asked if they'd take a 50/50 gamble on winning $20 or losing $15a risk most people will reject, "even though the net expected outcome is positive," Adolphs says.........
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February 9, 2010, 9:05 AM CT
Lower detection of prostate cancer with PSA screening in US
Fewer prostate cancers were detected by prostate-specific antigen (PSA) screening in the U.S. than in a European randomized trial because of lower screening sensitivity, as per a new brief communication published online February 8 in the Journal of the National Cancer Institute
To compare the PSA screening performance in a clinical trial with that in a population setting, Elisabeth M. Wever, MSc, Department of Public Health, Erasmus Medical Center, the Netherlands, and his colleagues applied a microsimulation model developed for prostate cancer and screening to the European Randomized Study of Screening for Prostate Cancer (ERSPC)Rotterdam. The model was adapted by replacing the trial's demography parameters with U.S.-specific ones and the screening protocol with the frequency of PSA tests in the population. The natural progression of prostate cancer and the sensitivity (percentage of men correctly identified as having prostate cancer of those who have preclinical prostate cancer) of a PSA test followed by a biopsy were assumed to be the same in the US as in the trial.
The prostate cancer incidence predicted by the model in the U.S. was substantially higher than the actual prostate cancer incidence. However, the actual incidence was reproduced by assuming a substantially lower PSA test sensitivity in the U.S. than in ERSPCRotterdam.........
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February 9, 2010, 9:04 AM CT
Hypertension may predict dementia
Hypertension appears to predict the progression to dementia in elderly adults with impaired executive functions (ability to organize thoughts and make decisions) but not in those with memory dysfunction, as per a report in the recent issue of Archives of Neurology,
one of the JAMA/Archives journals.
"Eventhough midlife high blood pressure has been confirmed as a risk factor for the development of dementia in late life, there have been conflicting findings about the role of late-life hypertension," the authors write as background information in the article. Individuals with mild cognitive (thinking, learning and memory) impairmentthe state between aging-related brain changes and fully developed dementiamay experience deficits in different domains. For instance, some have impairments only in memory function and are more likely to develop Alzheimer's disease, whereas those whose impairment follows a stroke or other vascular (blood vesselrelated) event often experience executive dysfunction.
"Because high blood pressure is a major risk factor for vascular brain diseases and vascular cognitive impairment, we postulated that the cognitive domain of dysfunction appears to be the crucial factor that determines the association between high blood pressure and cognitive deterioration," the authors write. To test this hypothesis, Shahram Oveisgharan, M.D., of University of Western Ontario, Canada, and Isfahan University of Medical Sciences, Isfahan, Iran, and Vladimir Hachinski, M.D., F.R.C.P.C., D.Sc.(Lond)., also of University of Western Ontario, studied 990 elderly adults (average age 83) with cognitive impairment but no dementia.........
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February 8, 2010, 8:10 AM CT
Energy Released From a Virus During Infection
Within a virus's tiny exterior is a store of energy waiting to be unleashed. When the virus encounters a host cell, this pent-up energy is released, propelling the viral DNA into the cell and turning it into a virus factory. For the first time, Carnegie Mellon University physicist Alex Evilevitch has directly measured the energy linked to the expulsion of viral DNA, a pivotal discovery toward fully understanding the physical mechanisms that control viral infection and designing drugs to interfere with the process.
"We are studying the physics of viruses, not the biology of viruses," said Evilevitch, associate professor of physics in the Mellon College of Science at Carnegie Mellon. "By treating viruses as physical objects, we can identify physical properties and mechanisms of infection that are common to a variety of viruses, regardless of their biological makeup, which could lead to the development of broad spectrum antiviral drugs".
Current antiviral medications are highly specialized. They target molecules essential to the replication cycle of specific viruses, such as HIV or influenza, limiting the drugs' use to specific diseases. Additionally, viruses mutate over time and appears to become less susceptible to the medication. Evilevitch's work in the burgeoning field of physical virology stands to provide tools for the rational design of less-specialized antiviral drugs that will have the ability to treat a broad range of viruses by interrupting the release of viral genomes into cells.........
Posted by: Mark Read more Source
February 8, 2010, 8:04 AM CT
Stillbirth in women with fibroids
In a study to be presented today at the Society for Maternal-Fetal Medicine's (SMFM) annual meeting, The Pregnancy Meeting , in Chicago, scientists will unveil findings that show that there is an increased risk of intrauterine fetal death (IUFD), usually known as stillbirth, in women who have fibroids.
IUFD, or still birth, is rare and affects only six to seven out of every thousand births.
The study, conducted by scientists at Washington University in St. Louis, Mo., identified women who had fibroids detected during their routine second trimester ultrasound for anatomic survey at 16-22 weeks.
"Fibroids are very common," said Dr. Molly J. Stout, one of the study's authors. "We think they occur in 5% to 20% of all women, but most women are asymptomatic and don't even know they have them".
The study was a retrospective cohort study of 64,047 women. Data were extracted on maternal sociodemographics, medical history, and obstetric outcomes. Pregnancies with any fetal anomalies were excluded. Women with at least one fibroid detected at the time of fetal anatomic survey were in comparison to women without fibroids. The primary outcome was IUFD after 20 weeks gestation. Univariate and multiple logistic regression analyses were used to estimate the risk of IUFD in women with fibroids, and subgroup was conducted by presence or absence of fetal growth restriction (IUGR).........
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February 8, 2010, 7:57 AM CT
Genetic variant linked to biological aging
Researchers announced recently (7 Feb) they have identified for the first time definitive variants linked to biological ageing in humans. The team analyzed more than 500,000 genetic variations across the entire human genome to identify the variants which are located near a gene called TERC.
The study in Nature Genetics
published recently by scientists from the University of Leicester and King's College London, working with University of Groningen in the Netherlands, was funded by The Wellcome Trust and the British Heart Foundation.
British Heart Foundation Professor of Cardiology at the University of Leicester Professor Nilesh Samani, of the Department of Cardiovascular Sciences, who co-led the project explained that there are two forms of ageing chronological ageing i.e. how old you are in years and biological ageing whereby the cells of some individuals are older (or younger) than suggested by their actual age.
He said: "There is accumulating evidence that the risk of age-associated diseases including heart disease and some types of cancers are more closely correlation to biological rather than chronological age.
"What we studied are structures called telomeres which are parts of one's chromosomes. Individuals are born with telomeres of certain length and in a number of cells telomeres shorten as the cells divide and age. Telomere length is therefore considered a marker of biological ageing.........
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