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Toward fixing damaged hearts through tissue engineering

 Someone suffers a heart attack every 34 seconds -- their heart is starved of oxygen and suffers irreparable damage. Engineering new heart tissue in the laboratory that could eventually be implanted into patients could help, and scientists are reporting a promising approach tested with rat cells. They published their results on growing cardiac muscle using a scaffold containing carbon nanofibers in the ACS journal Biomacromolecules.

Gordana Vunjak-Novakovic, Rui L. Reis, Ana Martins and colleagues point out that when damaged, adult heart tissue can't heal itself very well. The only way to fix an injured heart is with a transplant. But within the past decade, interest in regenerating just the lost tissue has surged. The trick is to find materials that, among other things, are nontoxic, won't get attacked by the body's immune system and allow for muscle cells to pass the electrical signals necessary for the heart to beat. Previous research has found that chitosan, which is obtained from shrimp and other crustacean shells, nearly fits the bill. In lab tests, scientists have used it as a scaffold for growing heart cells. But it doesn't transmit electrical signals well. Vunjak-Novakovic's team decided to build on the chitosan development and coax it to function more like a real heart.

To the chitosan, they added carbon nanofibers, which can conduct electricity, and grew neonatal rat heart cells on the resulting scaffold. After two weeks, cells had filled all the pores and showed far better metabolic and electrical activity than with a chitosan scaffold alone. The cells on the chitosan/carbon scaffold also expressed cardiac genes at higher levels.

Source: sciencedaily.com

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Discovery of 'Fat' Taste Could Hold the Key to Reducing Obesity

A newly discovered ability for people to taste fat could hold the key to reducing obesity, Deakin University health researchers believe.

Deakin researchers Dr Russell Keast and PhD student Jessica Stewart, working with colleagues at the University of Adelaide, CSIRO, and Massey University (New Zealand), have found that humans can detect a sixth taste -- fat. They also found that people with a high sensitivity to the taste of fat tended to eat less fatty foods and were less likely to be overweight. The results of their research are published in the latest issue of the British Journal of Nutrition.

"Our findings build on previous research in the United States that used animal models to discover fat taste," Dr Keast said.

"We know that the human tongue can detect five tastes -- sweet, salt, sour, bitter and umami (a taste for identifying protein rich foods). Through our study we can conclude that humans have a sixth taste -- fat."

The research team developed a screening procedure to test the ability of people to taste a range of fatty acids commonly found in foods.

They found that people have a taste threshold for fat and that these thresholds vary from person to person; some people have a high sensitivity to the taste while others do not.

"Interestingly, we also found that those with a high sensitivity to the taste of fat consumed less fatty foods and had lower BMIs than those with lower sensitivity," Dr Keast said.

"With fats being easily accessible and commonly consumed in diets today, this suggests that our taste system may become desensitised to the taste of fat over time, leaving some people more susceptible to overeating fatty foods.

"We are now interested in understanding why some people are sensitive and others are not, which we believe will lead to ways of helping people lower their fat intakes and aide development of new low fat foods and diets

Source: Science Daily

N.H.Khider

Aggression Strongly Associated With Genetic Factors

The development of physical aggression in toddlers is strongly associated with genetic factors and to a lesser degree with the environment, according to a new study led by Eric Lacourse of the University of Montreal and its affiliated CHU Sainte-Justine Hospital. Lacourse's worked with the parents of identical and non-identical twins to evaluate and compare their behavior, environment and genetics.

"The gene-environment analyses revealed that early genetic factors were pervasive in accounting for developmental trends, explaining most of the stability and change in physical aggression, " Lacourse said. "However, it should be emphasized that these genetic associations do not imply that the early trajectories of physical aggression are set and unchangeable. Genetic factors can always interact with other factors from the environment in the causal chain explaining any behavior."

Lacourse and his colleagues posited and tested three general patterns regarding the developmental roles of genetic and environmental factors in physical aggression. First, the most consensual and general point of view is that both sources of influence are ubiquitous and involved in the stability of physical aggression. Second, a "genetic set point" model suggests a single set of genetic factors could account for the level of physical aggression across time. A third pattern labeled 'genetic maturation' postulates new sources of genetic and environmental influences with age. "According to the genetic maturation hypothesis, new environmental contributions to physical aggression could be of short duration in contrast to genetic factors," Lacourse explained

Source: .sciencedaily.com

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It's All Coming Back to Me Now: Researchers Find Caffeine Enhances Memory

For some, it's the tradition of steeping tealeaves to brew the perfect cup of tea. For others, it's the morning shuffle to a coffee maker for a hot jolt of java. Then there are those who like their wake up with the kind of snap and a fizz usually found in a carbonated beverage.

Regardless of the routine, the consumption of caffeine is the energy boost of choice for millions to wake up or stay up. Now, however, researchers at the Johns Hopkins University have found another use for the stimulant: memory enhancer.

Michael Yassa, assistant professor of psychological and brain sciences in the Krieger School of Arts and Sciences at Johns Hopkins, and his team of scientists found that caffeine has a positive effect on long-term memory in humans. Their research, published by the journal Nature Neuroscience, shows that caffeine enhances certain memories at least up to 24 hours after it is consumed.

The memory center in the human brain is the hippocampus, a seahorse-shaped area in the medial temporal lobe of the brain. The hippocampus is the switchbox for all short-term and long-term memories. Most research done on memory -- the effects of concussions in athletics to war-related head injuries to dementia in the aging population -- are focused on this area of the brain.

Until now, caffeine's effects on long-term memory had not been examined in detail. Of the few studies done, the general consensus was that caffeine has little or no effect on long-term memory retention.

" According to the U.S. Food and Drug Administration, 90 percent of people worldwide consume caffeine in one form or another. In the United States, 80 percent of adults consume caffeine every day. The average adult has an intake of about 200 milligrams -- the same amount used in the Yassa study -- or roughly one strong cup of coffee or two small cups of coffee per day.

 Source : Science Daily

N.H.Khider

Dance and Virtual Reality: A Promising Treatment for Elderly Women

Virtual reality, dance and fun are not the first things that come to mind when we think of treating urinary incontinence in senior women. However, these concepts were the foundations of a promising study by Dr. Chantal Dumoulin, PhD, Canada Research Chair in Urogynaecological Health and Aging, a researcher at the Institut universitaire de gériatrie de Montréal, and an associate professor in the Physiotherapy Program of the Rehabilitation School at Université de Montréal, and her master's student, Miss Valérie Elliott.

For the study, the researchers added a series of dance exercises via a video game console to a physiotherapy program for pelvic floor muscles. What were the results for the 24 participants? A greater decrease in daily urine leakage than for the usual program (improvement in effectiveness) as well as no dropouts from the program and a higher weekly participation rate (increase in compliance).

According to the researchers, fun is a recipe for success. "Compliance with the program is a key success factor: the more you practice, the more you strengthen your pelvic floor muscles. Our challenge was to motivate women to show up each week. We quickly learned that the dance component was the part that the women found most fun and didn't want to miss. The socialization aspect shouldn't be ignored either: they laughed a lot as they danced!" explained a delighted Chantal Dumoulin.

The dance period also served as a concrete way for women to apply pelvic floor muscle exercises that are traditionally static. "Dancing gives women confidence, as they have to move their legs quickly to keep up with the choreography in the video game while controlling their urine. They now know they can contract their pelvic floor muscles when they perform any daily activity to prevent urine leakage. These exercises are therefore more functional."

Although a lot of research already employs different aspects of virtual reality, this is the first time that it has been used to treat urinary incontinence. This successful feasibility study opens the door to a randomized clinical trial.

Source: sciencedaily.com

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