Researchers noted that breast cancer may be developing in more women at younger ages.
The findings presented at the 2009 Breast Cancer Symposium, held last week in San Francisco, could potentially affect how women are screened for breast cancer.
Reserachers reported that women with a high genetic risk of developing breast cancer are being diagnosed sooner than similar women in the past. They note this may suggest that tumors are being found earlier in the younger generation.
About 5 percent to 10 percent of breast cancer cases are thought to be connected to a genetic mutation that is also linked to ovarian cancer. Women with the mutations, known as BRCA1 or BRCA2, have an increased risk of developing breast tumors the scientists noted. Over a lifetime, 60 percent of these women will develop the disease, according to the American Cancer Society. By comparison, 12 percent of women in the general population will develop breast cancer.
Scientists have countered findings of previous clinical trials by showing that giving supplemental oxygen to animals during a stroke can reduce damage to brain tissue surrounding the clot.
The timing of the delivery of 100 percent oxygen - either by mask or in a hyperbaric chamber - is critical to achieving the benefit, however.
"The use of supplemental oxygen after blood flow is restored in the brain appears to actually cause harm by unleashing free radicals," said Savita Khanna, assistant professor of surgery at Ohio State University and principal investigator of the research. "The resulting tissue damage was worse than stroke-affected tissue that received no treatment at all."
Previous clinical trials in humans have suggested that administering oxygen under pressure could harm stroke patients. But the studies did not take into account the status of blood flow in the brain at the time the oxygen was delivered, Khanna noted.
MIT researchers have identified populations of neurons that code time with extreme precision in the primate brain. These neurons are found in two interconnected brain regions, the prefrontal cortex and the striatum, both of which are known to play critical roles in learning, movement, and thought control.
The timing of individual actions, whether we are speaking, driving a car, or playing the piano, require very precise control. Although our daily life is extremely dependent on this remarkable capability, surprisingly little has been known about how time is represented in the activity of brain cells. The discovery made by MIT neuroscientists is an important step toward answering this fundamental question.
The team of researchers, led by Institute Professor Ann Graybiel, a member of the McGovern Institute for Brain Research and the Department of Brain and Cognitive Sciences, trained two macaque monkeys to perform a simple eye-movement task. After receiving a "go" signal, the monkeys were free to perform the task at their own speed. The researchers found that neurons in the prefrontal cortex and the striatum that consistently fired at specific times - 100 milliseconds, 110 msec, 150 msec, and so on - after the "go" signal. Like a stopwatch, these neurons provided a fine-scale coverage over a period of several seconds. The combined activity of these neurons provided "time stamps" that could specify any given time point with a remarkable precision of less than 50 milliseconds, more than sufficient to account for most behaviors.
Biologists long have marveled at the ability of some animals to re-grow lost body parts. Newts, for example, can lose a leg and grow a new one identical to the original. Zebrafish can re-grow fins.
These animals and others also can repair damaged heart tissue and injured structures in the eye. In contrast, humans have only rudimentary regenerative abilities, so scientists hoping eventually to develop ways of repairing or replacing damaged body parts are keenly interested in understanding in detail how the process of regeneration works.
Using zebrafish as a model, researchers at the University of Michigan have found that some of the same genes underlie the process in different types of tissues. Genes involved in fin regeneration and heart repair are also required for rebuilding damaged light receptors in the eye, they found, suggesting that a common molecular mechanism guides the process, no matter what body part is damaged.
Study delves into why harmonic sounds are therapeutic for people with neurological disorders
Call it the non-druggy drug: Music can promote memory, social behavior and communication in patients with severe brain disorders, but researchers don't understand how music works in the human brain to improve mental powers and the ability to interact with others.
Now, new research in monkeys suggests that humans' ability to perceive music may have been developed through the ability of animals to communicate with one another using vocalizations. After all, the researchers noted, the sounds of human speech have much in common with the sounds made by animals. For example, human speech and animal vocalizations contain the same kinds of tones, which are known as "complex tones."
Researchers at Georgetown University Medical Center studied brain activity in the auditory cortex of monkeys. They found that the brain cells known as neurons were tuned to certain frequencies and harmonic sounds.
Infants as young as five months old are able to correctly identify humans as the source of speech and monkeys as the source of monkey calls, psychology researchers have found. Their finding, which appears in the latest issue of the Proceedings of the National Academy of Sciences (PNAS), provides the first evidence that human infants are able to correctly match different kinds of vocalizations to different species.
The study's co-authors were: Athena Vouloumanos, an assistant professor in New York University's Department of Psychology; Madelynn Druhen, a doctoral candidate in the Department of Psychology at the University of North Carolina at Greensboro; Marc Hauser, a professor in Harvard University's Departments of Psychology and Human Evolutionary Biology; and Anouk Huizink, a researcher in McGill University's Department of Psychology. The research was conducted at the McGill Infant Development Centre and the NYU Infant Cognition and Communication Lab, under the direction of Vouloumanos.
While young children know that humans speak, monkeys grunt, and ducks quack, it's not clear when we come to know which vocalizations each of these animals produce. Although much is known about infants' abilities to match properties of human voices to faces, such as emotion, it is unknown whether infants are able to match vocalizations to the specific species that produces them. In the PNAS study, the team of psychologists explored this question by asking whether young infants expect humans, but not other animals, to produce speech, and also, whether infants can identify the sources of vocalizations produced by other species.
Researchers pinpoint individual brain cells that respond to particular people, objects
The Halle Berry fan club is expanding one brain cell at a time. By eavesdropping on the activity of single neurons in the human brain, scientists have figured out which brain cells go wild for superstars such as the popular actress.
"This study is the first demonstration of humans' ability to control the activity of single neurons," the researchers wrote in a summary of their study. The results, presented October 19 at the Society for Neuroscience's annual meeting by Moran Cerf of the California Institute of Technology in Pasadena, may help researchers understand how each cell in the brain sees and responds to the world.
"This type of work gives us some clues about what's going on in the brain," comments Christoph Weidemann of the University of Pennsylvania, who studies how the brain processes information. "It's quite an amazing feat for the brain to make sense of its input and reliably recognize people and objects."
Study of rhesus monkeys shows running protects dopamine neurons from death
A toned, buff bod isn't the only thing a workout is good for. Exercise protects special brain cells in monkeys' brains and improves motor function, a new study finds. The data, presented at a news briefing October 18 in Chicago at the Society for Neuroscience's annual meeting, adds to a growing body of evidence that shows exercise is good for the brain, too.
"This is sort of a quiet revolution that's been occurring in neuroscience," says Carl Cotman, a brain aging expert at the University of California, Irvine, "to realize that physical activity at a certain level impacts the brain in a really profound way."
In the new study, researchers led by Judy Cameron of the University of Pittsburgh trained six adult female rhesus monkeys to run on treadmills built for humans. Over a period of three months, monkeys either ran, jogged or sat on a treadmill for five hours each week. Monkeys that ran got their heart rates to about 80 percent of maximum, comparable to a human training program that would increase cardiovascular fitness. The jogging monkeys' heart rates reached about 60 percent of maximum.
Mercury pollution is a persistent problem in the environment. Human activity has lead to increasingly large accumulations of the toxic chemical, especially in waterways, where fish and shellfish tend to act as sponges for the heavy metal.
It's that persistent and toxic nature that has flummoxed scientists for years in the quest to find ways to mitigate the dangers posed by the buildup of mercury in its most toxic form, methylmercury.
A new discovery by scientists at the University of Tennessee, Knoxville, and Oak Ridge National Laboratory, however, has shed new light on one of nature's best mercury fighters: bacteria.
Depression, anxiety disorders and sexual trauma have all been implicated as risk factors in lower urinary tract symptoms (LUTS) such as incontinence and overactive bladder. The exact nature of these associations is unknown. In a study published online in The Journal of Urology, researchers from the Division of Urology, Virginia Commonwealth University School of Medicine and the Hunter Holmes McGuire Veterans Affairs Hospital, Richmond, Virginia, explored the possible association of LUTS with those factors.
Two questionnaires, the Urogenital Distress Inventory-6 and Incontinence Impact Questionnaire-7, were administered to 121 women referred to a specialized urology clinic for evaluation of lower urinary tract symptoms. These data were then analyzed according to psychiatric comorbidities, history of sexual trauma, age, race and obstetric history. Baseline incidence of psychiatric comorbidity and sexual trauma was also compared to a control population of 1,298 women from the Veterans Affairs primary care clinic.
Women referred for evaluation of lower urinary tract symptoms had higher rates of psychiatric comorbidities (64.5% vs. 25.9%) and sexual trauma (49.6% vs. 20.1%) compared to those in the primary care clinic. Separate analysis showed that women younger than 50 years and with a history of miscarriage had higher Urogenital Distress Inventory-6 scores, while higher Incontinence Impact Questionnaire-7 scores were associated only with psychiatric comorbidities and history of miscarriage.
