April 24, 2006, 6:35 PM CT

Reproductive Success In Early Life Leads To Faster Ageing

Why do we stop reproducing after a certain age, and how is this age determined? A study by Oxford University scientists has shed light on this question by studying data from Dorset swans.

A theory which says that reproductive success in early life will lead to faster ageing later has been supported by the study of mute swans (Cygnus olor) which shows that those swans which reproduce early in life also stopped breeding early, and vice versa. Which pattern a swan adopts appears to be genetically inherited.

The team, from the Edward Grey Institute in Oxford's Department of Zoology, investigated data on swans that bred as youngsters and those that started to reproduce at a much later age. They discovered the age at which swans started to reproduce varied considerably - from two to twelve years old - and the age at which swans stopped breeding also showed huge variation - from two to twenty years old. The main finding, however, was that the birds that started breeding at an early age stopped reproducing earlier than the late-starters.

The study, would be reported in the science journal PNAS this week, supports the 'antagonistic pleiotropy' theory for the evolution of ageing, that says that you 'pay' in later life for your success in reproducing when young. It is thought the study is the first to show this pattern in a wild animal population.........

Posted by: Scott      Permalink         Source

April 24, 2006, 6:31 PM CT

Genetic Variation Cuts 'bad' Cholesterol

People fortunate enough to have specific variations in a single gene enjoy moderately lower levels of "bad cholesterol" in their blood and significantly lower risk for coronary heart disease over their lifetimes, scientists from two University of Texas institutions report this week in the New England Journal of Medicine.

For the vast majority of people who don't enjoy this genetic protection, the scientists note, the findings have an important lesson: early, consistent and moderate reductions in low-density lipoprotein would markedly reduce lifetime risk of coronary heart disease.

The study by researchers from The University of Texas Health Science Center at Houston and The University of Texas Southwestern Medical Center in Dallas looked at the impact of specific variations in the gene among 3,363 blacks and 9,524 whites over 15 years.

They found that variations in the gene reduced LDL by 28 percent among blacks, leading to an 88 percent reduction in coronary heart disease. A separate variation in whites was associated with a 15 percent reduction in LDL cholesterol and a 50 percent reduction in heart disease risk.

Only 2.6 percent of blacks had the protective variation in the proprotein convertase subtilisin/kexin type 9 serine protease gene (PCSK9 for short). Only 3.2 percent of white subjects had a separate variation in the same gene.........

Posted by: Daniel      Permalink         Source

April 23, 2006, 10:52 PM CT

Family History Of Alcoholism

Prior research has shown that individuals with a family history of alcoholism (FH+) have a greater risk of developing alcoholism themselves than do persons with no such history (FH-). A study in the recent issue of Alcoholism: Clinical & Experimental Research has found that FH+ individuals who are male and have behavioral disinhibition have the greatest risk of developing alcoholism. However, a higher risk does not equate certainty.

"The development of alcoholism among individuals with a family history of alcoholism is about four to eight times more common than it is among individuals with no such family history," said William R. Lovallo, Director of the Behavioral Sciences Laboratories at the Veterans Affairs Medical Center, Oklahoma City and corresponding author for the study. "Eventhough the definition of 'family history' is different as per different researchers, we define it as when either or both of the person's parents have had an alcohol problem."

"Previous research has shown that male gender and behavioral disinhibition are strong predictors of alcohol problems," added Peter R. Finn, professor of psychology at Indiana University, Bloomington. "Behavioral disinhibition reflects a general disposition characterized by an apparent insensitivity to punishment, an increased sensitivity to immediate rewards, a tendency to prefer immediate smaller rewards as opposed to larger long-term rewards, and a failure to consider and inhibit behavior when aversive consequences are likely. Those high in behavioral disinhibition are probably more likely to experiment with substance use earlier, because they are less inhibited by the prospect of negative consequences and less likely to learn to moderate their consumption once they have initiated use. Some research suggests that the presence of a family history of alcoholism amplifies this risk."........

Posted by: JoAnn      Permalink         Source

April 23, 2006, 10:49 PM CT

Alcoholism And Chronic Smoking Can Damage Brain

Alcoholism is usually associated with chronic smoking, and both alcohol and nicotine are believed to act on the same brain region. A study in the recent issue of Alcoholism: Clinical & Experimental Research builds upon prior research that identified four potential alcohol-sensitive genes in the prefrontal cortex, finding that smoking also influences the expression of these genes.

"Nicotine and alcohol are both addictive drugs," said Traute Flatscher-Bader, a postdoctoral research officer at the Alcohol Research Unit of the University of Queensland, Brisbane and corresponding author for the study. "They act on the same brain region, the 'drug reward pathway' or mesocorticolimbic system (MDS). The MDS contains the 'feel-good' neurotransmitter dopamine. Acute nicotine and alcohol cause an imbalance within the MDS by artificially increasing dopamine levels through direct and/or indirect modulation of dopaminergic neurons. While the long-term effect of alcoholism on the human brain has been investigated, surprisingly little is known about the long-term effect of nicotine on specific regions of the drug reward pathway in the human brain."

"Studies into the molecular changes that alcohol and smoking have on the body and especially the brain are crucial for understanding the disease state," said Nikki Zuvela, a doctoral student in molecular neuroscience at The University of Queensland. "There are actual molecular changes to parts of the brain involved in developing addiction; most importantly, within those centres known to mediate desire, craving, pleasure, self control, decision making, fear and emotion."........

Posted by: Janet      Permalink         Source

April 23, 2006, 10:42 PM CT

Attention shoppers: Neurons that encode the value of different goods

Scientists at Harvard Medical School (HMS) report in the April 23 issue of Nature that they have identified neurons that encode the values that subjects assign to different items. The activity of these neurons might facilitate the process of decision-making that occurs when someone chooses between different goods.

"We have long known that different neurons in various parts of the brain respond to separate attributes, such as quantity, color, and taste. But when we make a choice, for example: between different foods, we combine all these attributes--we assign a value to each available item," says Camillo Padoa-Schioppa, PhD, HMS research fellow in neurobiology and lead author of the paper. "The neurons we have identified encode the value individuals assign to the available items when they make choices based on subjective preferences, a behavior called 'economic choice.'".

Everyday examples of economic choice include choosing between working and earning more or enjoying more leisure time, or choosing to invest in bonds or in stocks. Such choices have long been studied by economists and psychology experts. In particular, research in behavioral economics shows that in numerous circumstances, peoples' choices violate the criteria of economic rationality. This motivates a currently growing interest for the neural bases of economic choice--an emerging field called "neuroeconomics." In general, it is believed that economic choice involves assigning values to available options. However, the underlying brain mechanisms are not well understood.........

Posted by: JoAnn      Permalink         Source

April 23, 2006, 10:39 PM CT

Groups Perform Better Than The Best Individual

Groups of three, four, or five perform better on complex problem solving than the best of an equivalent number of individuals, says a new study appearing in the recent issue of the Journal of Personality and Social Psychology, published by the American Psychological Association (APA). This finding may transfer to scientific research teams and classroom problem solving and offer new ways for students to study and improve academic performance, as per the study authors.

In this study 760 students from the University of Illinois at Urbana- Champaign solved two letters-to-numbers coding problems as individuals or as groups of two, three, four and five people. Prior research has shown that groups perform better than the average individual on a wide range of problems. However, this study tested the relationship between group size and performance as compared to that of an equivalent number of individuals by comparing the number of trials to solutions and answers given for complex problems. The groups of three, four, and five performed better than the best of an equivalent number of individuals on the letters-to-numbers problems.

"We found that groups of size three, four, and five outperformed the best individuals and attribute this performance to the ability of people to work together to generate and adopt correct responses, reject erroneous responses, and effectively process information," said lead author Patrick Laughlin, PhD., of the University of Illinois at Urbana-Champaign.........

Posted by: Janet      Permalink         Source

April 23, 2006, 9:23 PM CT

How Insulin-producing Beta Cells Grow And Function

A new Joslin Diabetes Center-led study has shown conclusively that two receptors in the insulin-producing beta cell do not affect developmental growth, refuting a long-held hypothesis in diabetes research. This finding is helping researchers in their efforts to isolate the growth factors that do stimulate beta cell growth and understand the defects in insulin production and secretion that cause diabetes.

These two receptors have been a major focus of research on beta cell development as researchers seek to find ways to promote the growth of these essential insulin-producing cells in diabetes patients. This latest research will appear in an upcoming issue of Nature Genetics and will be published online April 23 on the journal's Web site, http://www.nature.com/ng.

In two prior Joslin studies, insulin receptor, a protein that mediates the action of insulin, and the receptor for insulin-like growth factor I (IGF-I), a hormone, which were suggested as critical for mediating islet/beta cell development and growth, were individually "knocked out" in beta cells in genetically altered mice. Scientists were surprised to discover that the beta cells developed and grew normally without these receptors, as per Rohit N. Kulkarni, M.D., Ph.D., Investigator at Joslin Diabetes Center and Assistant Professor of Medicine at Harvard Medical School, who led the latest study and was lead author in the two prior Joslin studies.........

Posted by: JoAnn      Permalink         Source

April 22, 2006, 6:08 PM CT

Protein That Kills Anthrax Bacteria

Not all biological weapons are created equal. They are separated into categories A through C, category A biological agents being the scariest: They are easy to spread, kill effectively and call for special actions by the pubic health system. One of these worrisome organisms is anthrax, which has already received its fair share of media attention. But work in Vince Fischetti's laboratory at Rockefeller University suggests that a newly discovered protein could be used to fight anthrax infections and even decontaminate areas in which anthrax spores have been released.

"Anthrax is the most efficient biowarfare agent. Its spores are stable and easy to produce, and once someone inhales them, there is only a 48-hour window when antibiotics can be used," says Fischetti. "We've found a new protein that could both potentially expand that therapy window and be used as a large-scale decontaminant of anthrax spores." Because anthrax spores are resistant to most of the chemicals that emergency workers rely on to sterilize contaminated areas, a solution based on the protein would be a powerful tool for cleaning up after an anthrax attack.

All bacteria, anthrax included, have natural predators called bacteriophage. Just as viruses infect people, bacteriophage infect bacteria, reproduce, and then kill their host cell by bursting out to find their next target. The bacteriophage use special proteins, called lysins, to bore holes in the bacteria, causing them to literally explode. Fischetti and his colleagues identified one of these lysins, called PlyG, in 2004, and showed that it could be used to help treat animals and humans infected by anthrax. Now, they have identified a second lysin, which they have named PlyPH, with special properties that make it not only a good therapeutic agent, but also useful for large-scale decontamination of areas like buildings and military equipment.........

Posted by: Mark      Permalink         Source

April 22, 2006, 5:44 PM CT

Link Between Television Viewing and Overweight in Children

Scientists from the Harvard School of Public Health (HSPH) and Children's Hospital Boston found that kids who spend more time watching television also eat more of the calorie-dense, low-nutrient foods advertised on television. Prior studies had demonstrated that children who watch more television are more likely to be overweight, but this is the first time a research team has found evidence for a mechanism explaining that relationship. The study results appear in the April 2006 issue of the Archives of Pediatric and Adolescent Medicine.

"We've known for a long time that television viewing is a risk factor for overweight, though the common perception is that this is due to the fact that it's a sedentary use of time," said Jean Wiecha, the study's lead author and a senior research scientist at HSPH. "This study provides evidence that television is effective in getting kids to eat the foods that are advertised, and this drives up their total calorie intake".

Wiecha and her colleagues collected baseline data on dietary patterns and television viewing habits for 548 Boston-area students in sixth and seventh grade and then repeated these measurements 19 months later. When surveying the students about their food intake, the scientists asked specifically about snacks and beverages usually advertised on television, such as soda, chips, fast food and baked snacks like cookies. Students were also asked to estimate the number of hours spent watching television each day of the week.........

Posted by: JoAnn      Permalink         Source

April 22, 2006, 5:28 PM CT

Secondhand Smoke And Heart Disease

Whether exposure to secondhand smoke increases the chance that children with a family history of cardiovascular disease will develop the disease themselves is under study at the Medical College of Georgia.

If those children also have a variation in at least one of four genes responsible for metabolizing nicotine, their risk may increase even more because nicotine might stay in the body longer and do more damage, an interdisciplinary research team says.

Scientists will study 585 children age 15-20 who have a parent, grandparent or both with essential high blood pressure and/or a heart attack by age 55.

"What I hope to take away from this is more information for parents and caregivers - to be able to share with them information about the risk of future disease that their behavior places on their child," says Dr. Martha Tingen, a nurse researcher at the Georgia Prevention Institute and principal investigator on the $220,000 National Institute of Nursing Research grant.

Scientists will look for adverse clinical cardiovascular measures, including reduced ability of arteries to dilate; the blood encountering increased resistance as it travels through vessels; higher blood pressure; and an increase in the size of the pumping chamber of the heart - a result of pumping against elevated pressure.........

Posted by: Daniel      Permalink         Source