Saturday, November 14, 2009


0 comentarios

A world first study by Monash University researchers into the health of families who drink rainwater has found that it is safe to drink.

The research was led by Associate Professor Karin Leder from the Department of Epidemiology and Preventive Medicine in conjunction with Water Quality Research Australia (previously the Cooperative Research Centre for Water Quality and Treatment).

"This is the first study of its kind. Until now, there has been no prospective randomised study to investigate the health effects of rainwater consumption, either in Australia or internationally," Associate Professor Leder said.

The study involved three hundred volunteer households in Adelaide that were given a filter to treat their rainwater. Only half of the filters were real while the rest were 'sham' filters that looked real but did not contain filters.

The householders did not know whether they had a real filter. Families recorded their health over a 12-month period, after which time the health outcomes of the two groups were compared.

"The results showed that rates of gastroenteritis between both groups were very similar. People who drank untreated rainwater displayed no measurable increase in illness compared to those that consumed the filtered rainwater," Associate Professor Leder said.

Adelaide was the location chosen for the study as it the city with the highest use of rainwater tanks in Australia.

Associate Professor Leder said some health authorities had doubts about drinking rainwater due to safety concerns, particularly in cities where good quality mains-water is available.

"This study confirms there is a low risk of illness. The results may not be applicable in all situations; nevertheless these findings about the low risk of illness from drinking rainwater certainly imply that it can be used for activities such as showering/bathing where inadvertent or accidental ingestion of small quantities may occur.

"Expanded use of rainwater for many household purposes can be considered and in current times of drought, we want to encourage people to use rainwater as a resource," she said.

(Photo: Monash U.)

Monash University


0 comentarios
If worms are any indication, all the sugar in your diet could spell much more than obesity and type 2 diabetes. Researchers reporting in the November issue of Cell Metabolism, a Cell Press publication, say it might also be taking years off your life.

By adding just a small amount of glucose to C. elegans usual fare of straight bacteria, they found the worms lose about 20 percent of their usual life span. They trace the effect to insulin signals, which can block other life-extending molecular players.

Although the findings are in worms, Cynthia Kenyon of the University of California, San Francisco, says there are known to be many similarities between worms and people in the insulin signaling pathways. (As an aside, Kenyon says she read up on low-carb diets and changed her eating habits immediately – cutting out essentially all starches and desserts -- after making the initial discovery in worms. The discovery was made several years ago, but had not been reported in a peer-reviewed journal until now.)

"In the early 90s, we discovered mutations that could double the normal life span of worms," Kenyon said. Those mutations effected insulin signals. Specifically, a mutation in a gene known as daf-2 slowed aging and doubled life span. That longer life depended on another "FOXO transcription factor" called DAF-16 and the heat shock factor HSF-1.

Now, the researchers show that those same players are also involved in numbering the days of worms who are fed on glucose. In fact, glucose makes no difference to the life span of worms that lack DAF-16 or HSF-1, they show. Glucose also completely prevents the life-extending benefits that would otherwise come with mutations in the daf-2 gene.

Ultimately, worms fed a steady diet containing glucose show a reduction in aquaporin channels that transport glycerol, one of the ingredients in the process by which the body produces its own glucose. "If there is not enough glucose, the body makes it with glycerol," Kenyon explained. That glycerol has to first get where it needs to go, which it does via the aquaporin channels.

Further studies are needed to see if these same effects of sugar can be seen in mice, or even people. But there is reason to think they may.

"Although we do not fully understand the mechanism by which glucose shortens the life span of C. elegans, the fact that the two mammalian aquaporin glycerol-transporting channels are downregulated by insulin raises the possibility that glucose may have a life-span-shortening effect in humans, and, conversely, that a diet with a low glycemic index may extend human life span," the researchers write. Kenyon also points to recent studies that have linked particular FOXO variants to longevity in several human populations, making the pathway the first with clear effects on human aging.

She says the findings may also have implications for drugs now in development for the treatment of diabetes, which are meant to block glucose production by inhibiting glycerol channels. The new findings "raise a flag" that glycerol channels might be doing something else, she says, and that drugs designed to block them might have a downside.

Cell Press


0 comentarios

In all the world, there are about 200 types of zeolite, a compound of silicon, aluminum and oxygen that gives civilization such things as laundry detergent, kitty litter and gasoline. But thanks to computations by Rice University professor Michael Deem and his colleagues, it appears there are -- or could be -- more types of zeolites than once thought.

A lot more.

A project that goes back 20 years came to fruition earlier this year when Deem, Rice's John W. Cox Professor in Biochemical and Genetic Engineering and a professor of physics and astronomy, and his team came up with a list that shows the structures of more than 2.7 million zeolite-like materials.

Of those, they found the thermodynamic characteristics of as many as 314,000 are near enough to currently known zeolites that it should be possible to manufacture these materials.

Creation of the public database is the focus of a new paper, "Computational Discovery of New Zeolite-Like Materials," posted online by the American Chemical Society's Journal of Physical Chemistry C and planned as the cover of the Dec. 24 print edition. The paper's authors include Ramdas Pophale, a postdoctoral research associate in Deem's lab; Phillip Cheeseman, senior scientific applications analyst at Purdue's Rosen Center for Advanced Computing; and David Earl, an assistant professor of chemistry at the University of Pittsburgh.

Zeolites can be viewed as "a membrane that will only let molecules of a certain size pass through," Deem said. "But they also do other things. They have an affinity for some molecules, so they're used to absorb odors, for instance, in flower shops."

In laundry detergents, zeolites trade soft ions for hard ones in the water, and the petrochemical industry uses zeolites to crack petroleum into gasoline, diesel and other products. After the accident at the Three Mile Island nuclear power plant, zeolites were used to adsorb radioactive ions.

Zeolites are a fine lattice, a molecular sieve that can let molecules of a certain size pass while blocking others. They can also adsorb molecules, attracting and gripping certain substances -- for which cats and their owners are grateful.

Natural zeolites are often the product of volcanic activity, as rocks, ash and alkaline water combine and crystallize over thousands of years. "The term zeolite comes from the combination of two Greek words that mean 'boiling' and 'stone,'" Deem said.

About a third of zeolites used for commercial purposes are mined, while the rest are synthesized into custom configurations that tend to be more pure, he said.

The fact that only 200 or so zeolites are known makes the creation of Deem's database a real breakthrough, as it gives industries new clues to optimizing their techniques. "That's one possibility, to look for related materials," he said. "In many catalytic applications, there's only one material that currently works."

It took serious computer time to figure out all the possibilities, said Deem, who has lately gained a measure of fame for his study of viruses, particularly H1N1. He began looking at zeolites two decades ago while at Exxon and published his first paper on the subject in the journal Nature. With support from the National Science Foundation (NSF) and the use of the Deem lab's Zefsa II software, researchers needed three years to complete the computations on the NSF's TeraGrid node at Purdue. "I think we were the biggest user of computer time there in 2006, and the fifth- or sixth-largest on the TeraGrid," Deem said. "At Purdue, we were making use of unused computer cycles, like the SETI@home project that searches for extraterrestrial life using people's home computers. We finished around the start of 2009."

The "big question," he said, is how to turn theoretical zeolites into real ones, a project his lab plans to pursue. "A couple of things have to happen. One is that we have to identify materials that look like they would have good properties, and then we have to find a synthesis mechanism to make those materials."

But how does one narrow the practicalities from 2.7 million possibilities? "It depends on the properties we're looking for," Deem said. "We have some ideas of what's practical, but of course we would love to work with other people."

(Photo: Rice U.)

Rice University


0 comentarios

Instead of killing cancer cells, researchers at Arizona State University will use the laws of physics to figure out how to control them. And, rather than treating cancer as a disease and seeking a cure, ASU scientists will view cancer cells as physical objects and study them the way a physicist would, using simple variables like temperature, pressure and force.

That fresh approach is behind a new research center at ASU – one of 12 Physical Sciences-Oncology Centers receiving some of $22.7 million in funding this fiscal year from the National Institutes of Health's National Cancer Institute. Each center will bring a non-traditional approach to cancer research with the goal of developing new methods of arresting tumor growth and metastasis.

In addition to ASU, other institutions receiving funding include: Johns Hopkins University, Massachusetts Institute of Technology, Memorial Sloan-Kettering Cancer Center, Northwestern University, Princeton University, H. Lee Moffitt Cancer Center and Research Institute, Cornell University, Scripps Research Institute, University of California-Berkeley, University of Southern California and University of Texas Health Science Center.

The new Center for Convergence of Physical Science and Cancer Biology at ASU will receive about $1.7 million in funding for each of the first two years of a five-year proposal. Part of the plan is the establishment of a "cancer forum," hosted by the BEYOND Center for Fundamental Concepts in Science at ASU.

"What is new about this initiative is that it is going to be tackling the root causes of cancer on a conceptual level," says Paul Davies, a theoretical physicist, cosmologist and astrobiologist who is leading the ASU cancer initiative. "We want physical scientists to think about why cancer exists in the first place. What is its role in the great biological scheme of things as life has evolved over the last several hundred million years? Within the human body, how does cancer behave as a physical object?"

Davies is experienced at asking these types of big questions. As director of the BEYOND Center in ASU's College of Liberal Arts and Sciences, Davies' work has focused on applying the laws of physics to the early universe, from the first split second. He is noted for his work on the theory of quantum fields in curved spacetime, the thermodynamics of black holes, the arrow of time, the nature of the laws of physics and the emergence of life in the universe.

"My interests have been very broad. I started out working on fundamental physics and cosmology and about 15 years ago became interested in astrobiology, which is the study of origin and distribution of life in the universe," Davies says.

"When I first began thinking about the problem of cancer, it occurred to me that physicists can do some pretty fancy things. If we can build the Large Hadron Collider to find the Higgs Boson amid one trillion proton collisions, maybe we can find clever ways of locating and zapping individual cancer cells in the human body. So I began to get excited about the prospect of just throwing the full panoply of toys that physicists use at the problem of diagnosing and killing cancer cells.

"Then, I came to realize that ‘think big and zap the problem' was probably not the best way to go. A more subtle approach to really understand cancer cells is to regard them as physical objects rather than as enemies to be destroyed. Cancer is a fascinating manifestation of an endlessly fascinating subject, namely life," Davies says.

"Cancer cells are, after all, physical objects," he notes. "Instead of thinking ‘oh, let's throw all these chemicals at them and see if we can kill them,' let's think of them as physical objects in the body or in isolation and study them in that way as a physicist would – we look at the forces that act upon them, look at their mechanical properties, their electrical properties, how they cluster, how they act as communities."

Surgeon John E. Niederhuber, director of the National Cancer Institute, says, "By bringing a fresh set of eyes to the study of cancer, these new centers have great potential to advance, and sometimes challenge, accepted theories about cancer and its supportive microenvironment."

Other collaborators on the ASU team include Stuart Lindsay, a Regents' Professor of physics and chemistry and director of the Center for Single Molecule Biophysics at the Biodesign Institute; Deirdre Meldrum, dean of the Ira A. Fulton Schools of Engineering and director of the Center for Ecogenomics at the Biodesign Institute; Timothy Newman, professor of physics and director of the Center for Biological Physics; Robert Ros, associate professor of physics; Peiming Zhang, an associate research professor in the Biodesign Institute; Roger Johnson, a research scientist and laboratory manager; and Pauline Davies, a professor of practice in the Hugh Downs School of Human Communication.

"We are also collaborating with the Fred Hutchinson Cancer Research Center, which will provide the cell lines for us, and the Mayo Clinic, which will provide tissue samples," Davies says.

"And, we will be looking at the mechanical properties of the cells. We have state-of-the-art equipment to examine individual cells in suspension in three dimensions. The problem when you look at a cell usually is that it's a slide, it has been squashed flat and stuck to a surface, it's a two-dimensional picture. We can examine cells in a three-dimensional suspension, we can examine them from all sides," says Davies. "So we can look at normal cells, cancer cells at various stages of progression, and we have an atomic force microscope that can be used to prod the cells and see how their mechanical properties change as the cancer progresses.

"It's well known that cancer cells get more squishy. The reason they get bent out of shape is because of the squishiness, they become less elastic. Nobody really knows what the reason for that is or whether this is something just to do with the membrane of the cell or the cytoskeleton – little tubes inside the cells that pull like ropes. We want to know what's going on in these cells. Why they are getting squishy? How does that effect the survival chances of the cancer cell?"

Taking that a step further, Davies asks, "Then, can we approach the problem of cancer by controlling the mechanical environment in some way instead of thinking about switching on genes and chemical pathways? Maybe we just need to control the physical environment. We've got simple variables like temperature and pressure and force and electric potential, these are the tools of the trade for physicists. Let's bring those to bear on cancer."

The center at ASU will be a think tank that hosts several workshops each year on topics related to the intersection of physical science and cancer. "The goal of the workshops is to serve as a catalyst to establish new lines of inquiry, both theoretical and experimental," Davies says. "We are aiming for that big conceptual breakthrough that would transform the subject, as opposed to the slow incremental progress that's been made so far using traditional approaches."

The center will also create a Web site to serve as a window on the research program and to host research papers, podcasts, webcasts and news items, Davies notes.

"The traditional approach to cancer is it is a disease to be cured. We are taking the approach that it is part of life's intrinsic exuberance that we wish to control," Davies says. "We don't have to cure cancer. All we have to do is to find ways of preventing it from taking over and destroying the body of the host."

(Photo: Deirdre Meldrum, Vivek Nandakumar, Laimonas Kelbauskas and Roger Johnson/Center for Ecogenomics/Biodesign Institute at ASU)

Arizona State University


0 comentarios
Everyday, people are required to make decisions quickly and flexibly. In a flash, they must weigh up the advantages, disadvantages and possible consequences of their behaviour and coordinate it with the relevant external circumstances. This learning process involves the messenger substance dopamine. Decisions that are perceived as positive and are followed by a reward trigger the increased release of dopamine and are recorded by the brain as beneficial. Researchers at the Max Planck Institute for Human Development have now discovered an enzyme variant that promotes fast and flexible decision-making behaviour.

It is known from previous studies that the COMT enzyme (cathecolamin-O-methyltransferase) breaks down dopamine and can, therefore, influence learning and thought processes. It is also known that there are two variants of the COMT enzyme (COMT Met and COMT Val) that influence dopamine levels to varying degrees. Lea Krugel and her colleagues from the Max Planck Institute for Human Development in Berlin investigated the question as to whether and how the influencing of the dopamine level by COMT-Met and COMT-Val in turn affects reward-dependent decision processes.

Individuals with the COMT-Val genotype learn faster from unexpected outcomes and are more flexible decision makers.

To this end, the scientists tested 26 young adults who exhibited either only the Met variant or the Val variant of the COMT enzyme (Met/Met or Val/Val genotype). The study participants received a monetary bonus for their performance in reward-based decision tests which examined how quickly and flexibly they learned from the consequences of their actions. Decisions involving different options are often influenced by the expected reward. A significant difference between the result achieved and the expected outcome generates an important signal for the alteration of decision behaviour.

It emerged from the study that the participants with the Val version of the genotype were the more flexible decision makers and could better learn from the differences between outcomes and expectations. With the help of functional magnetic resonance imaging (fMRT), Lea Krugel and her colleagues were able to demonstrate that this advantage was accompanied by greater nerve cell activity in certain regions of the brain in which the messenger substance dopamine is known to play a particularly prominent role. Hence, the scientists observed greater activity in the region of the brain known as the striatum and more intensive interaction between the striatum and frontal lobe (prefrontal cortex) in the participants with the Val version of the COMT enzyme.

Based on this, the scientists not only demonstrated a possible advantage for individuals with the Val version of enzyme, which is the more common variant throughout the world than the Met version, their results also provide new clues as to how the messenger substance dopamine helps people to make use of past decisions for future ones in the context of ongoing decision-making processes.

Max Planck Institute


0 comentarios
A study conducted by exercise physiologists in the University of Alabama at Birmingham (UAB) Department of Human Studies finds that as little as 80 minutes a week of aerobic or resistance training helps not only to prevent weight gain, but also to inhibit a regain of harmful visceral fat one year after weight loss.

The study was published online Oct. 8 and will appear in a future print edition of the journal Obesity.

Unlike subcutaneous fat that lies just under the skin and is noticeable, visceral fat lies in the abdominal cavity under the abdominal muscle. Visceral fat is more dangerous than subcutaneous fat because it often surrounds vital organs. The more visceral fat one has, the greater is the chance of developing Type 2 diabetes and heart disease.

In the study, UAB exercise physiologist Gary Hunter, Ph.D., and his team randomly assigned 45 European-American and 52 African-American women to three groups: aerobic training, resistance training or no exercise. All of the participants were placed on an 800 calorie-a-day diet and lost an average 24 pounds. Researchers then measured total fat, abdominal subcutaneous fat and visceral fat for each participant.

Afterward, participants in the two exercise groups were asked to continue exercising 40 minutes twice a week for one year. After a year, the study's participants were divided into five groups: those who maintained aerobic exercise training, those who stopped aerobic training, those who maintained their resistance training, those who stopped resistance training and those who were never placed on an exercise regimen.

"What we found was that those who continued exercising, despite modest weight regains, regained zero percent visceral fat a year after they lost the weight," Hunter said. "But those who stopped exercising, and those who weren't put on any exercise regimen at all, averaged about a 33 percent increase in visceral fat.

"Because other studies have reported that much longer training durations of 60 minutes a day are necessary to prevent weight regain, it's not too surprising that weight regain was not totally prevented in this study," Hunter said. "It's encouraging, however, that this relatively small amount of exercise was sufficient to prevent visceral fat gain."

The study also found that exercise was equally effective for both races.

University of Alabama at Birmingham (UAB)




Selected Science News. Copyright 2008 All Rights Reserved Revolution Two Church theme by Brian Gardner Converted into Blogger Template by Bloganol dot com