B4U India

Trial drug slows age-related macular degeneration in mice

Fri, 10 Oct 2008 04:52:00 -0400

A new study in mice has shown that retinylamine – a trial drug that has been tested in a medical school lab – markedly slows the progression of age-related macular degeneration (AMD).

The findings, by researchers at the Case Western Reserve University School of Medicine, provide evidence for biochemical change in the retina that resemble AMD.

The study was led by postdoctoral researcher Akiko Maeda, an investigator in the lab of one of her co-authors, Krzysztof Palczewski.

Palczewski, who is chair and the John H. Hord Professor of Pharmacology at the School of Medicine, said that AMD currently isn''t usually treated until toward the end of the disease.

However, with the discovery in his lab by Maeda and her research team, retinylamine can potentially prevent the rapid degeneration of the eye, slowing the rate of progression of AMD.

As humans go through the aging process, it eventually affects the vision and a fraction of those cases will progress further and potentially develop AMD.

Through their work on mouse models, Maeda and her team have learned to modify the genes that establish the rate of changes related to AMD.

However, the biochemical trigger of these changes had not been understood until now as a result of the retinylamine treatments.

"We have proven this observation, genetically, biochemically and pharmacologically. Dr. Maeda, who studies retinal degenerative diseases in my lab and works to develop models that will facilitate the evaluation of the safety and effectiveness of drug candidates designed to combat retinal disease in humans, has done superb work in this area. We''re very excited about the potential this outcome represents," Palczewski said.

"Until now, with the discovery in our lab, the genesis of that progression wasn''t known. Now we have the potential to intervene in the middle of the disease''s advancement so we can prevent rapid degeneration of the eye. The importance of this work also is illustrated by the five-year K08 award made to Dr. Maeda by the National Eye Institute," Palczewski said.

The study is reported in the prestigious Journal of Biological Chemistry. (ANI)

"Bold traveller" bug could be a ''goldmine'' of clues to life on other planets

Fri, 10 Oct 2008 04:50:00 -0400

A bug, discovered deep in a goldmine and nicknamed "the bold traveller" has got astrobiologists excited because of its unique ability to live in complete isolation of any other living species, suggesting it could be the key to life on other planets.

According to a report in New Scientist, a community of the bacteria Candidatus Desulforudis audaxviator has been discovered 2.8 kilometers beneath the surface of the Earth in fluid-filled cracks of the Mponeng goldmine in South Africa.

Its 60 degree Celsius home is completely isolated from the rest of the world, and devoid of light and oxygen.

Dylan Chivian of the Lawrence Berkeley National Laboratory, California, studied the genes found in samples of the fluid to identify the organisms living within it, expecting to find a mix of species.

Instead, he found that 99.9 percent of the DNA belonged to one bacterium, a new species. The remaining DNA was contamination from the mine and the laboratory.

"The fact that the community contains only one species stands one of the basic tenets of microbial ecology on its head," said Carl Pilcher, director of the NASA Astrobiology Institute.

A community of a single species is almost unheard of in the microbial world. It means the ecosystem''''s only species must extract everything it needs from an otherwise dead environment.

"Virtually all other known ecosystems on Earth that don''''t use sunlight directly do use some product of photosynthesis," said Pilcher.

Chivian''''s analysis shows that D. audaxviator gets its energy from the radioactive decay of uranium in the surrounding rocks. It has genes to extract carbon from dissolved carbon dioxide and other genes to fix nitrogen, which comes from the surrounding rocks.

Both carbon and nitrogen are essential building blocks for life as we know it, and are used in the building blocks of proteins, amino acids.

D. audaxviator has genes to produce all the amino acids it needs.

D. audaxviator can also protect itself from environmental hazards by forming endospores - tough shells that protect its DNA and RNA from drying out, toxic chemicals and from starvation. It has a flagellum to help it navigate.

It also represents the kind or organism that could survive below the surface of Mars or Saturn''''s sixth largest moon Enceladus.

According to Chivian, "One question that has arisen when considering the capacity of other planets to support life is whether organisms can exist independently, without access even to the Sun."

"The answer is yes and here''''s the proof. It''''s philosophically exciting to know that everything necessary for life can be packed into a single genome," he added. (ANI)

Largest ever dinos grew huge by not chewing their food

Fri, 10 Oct 2008 04:50:00 -0400

A new research has suggested that dinosaurs known as sauropods, which were the largest land animals that ever lived, grew huge and were an evolutionary success in part because they didn''''t bother to chew their food.

Sauropods weighed up to 88 tons (80 metric tons)-ten times more than an African elephant-and measured as high as 23 feet (7 meters).

The group of dinosaurs, which included the brachiosaurus and diplodocus, loomed over the animal kingdom for more than 140 million years until the late Cretaceous period, 65 million years ago.

Scientists think the animals evolved to be so large to discourage big predators, like Tyrannosaurus rex, from eating them. But how they maintained such massive body sizes has remained mysterious.

The herbivores, or plant-eaters, had hardly any teeth and are thought to have swallowed their food whole. They browsed large areas, barely moving and consuming vast quantities in short periods of time.

So, they needed long necks to reach food high in trees and a huge gut to process and break down their unchewed meals, Martin Sander, a palaeontologist at the University of Bonn in Germany and co-author of the study told National Geographic News.

"You can only have this long neck if you don''''t chew your food, otherwise your head would be full of teeth and too heavy to support," he said.

Paul Upchurch, an expert on sauropods from University College London, said that "most palaeontologists agree that feeding is the key to understanding sauropod gigantism."

To outgrow their predators, sauropods didn''''t just need lots of food. They also needed to develop fast, so they could attain their full size before being eaten, experts said.

Sauropod bones show that they did indeed grow swiftly. A 22-pound (10-kilogram) hatchling could become a 220,000-pound (100,000-kilogram) grown-up in about 20 to 30 years-quick by dinosaur time.

"This tells us that they must have been warm-blooded and had a high metabolic rate compared to cold-blooded creatures," said Sander. (ANI)

Washing hands better than pills for keeping colds at bay

Fri, 10 Oct 2008 04:48:00 -0400

They say popping vitamin C tablets can help colds, but a new research has shown that the pills do not provide nearly as much protection as other ‘natural’ measures, like frequently washing your hands.

What’s more, the researchers said that large doses of vitamin C can prove harmful for humans.

The German Institute for Quality and Efficiency in Health Care (IQWiG) has published information and a quiz on the subject of prevention, helping to separate widespread myths from facts.

For years it was believed that taking vitamin C supplements not only provided protection against colds, but also against cancer, thereby helping people to live longer. An easy-to-understand summary of the research in this area, refuting these beliefs, has now been published on IQWiG''s website www.informedhealthonline.org.

"Not only is there no proof that some antioxidants prolong life, but there is some evidence that certain products may even lead to earlier death", says Professor Peter Sawicki, the Institute''s Director.

"Positive" news gives people hope, which can quickly spread, become deeply held beliefs.

Professor Sawicki said: "It can be very difficult to accept that these beliefs are myths, but they are not true if further research does not confirm them or the research points to the opposite conclusion."

There are many simple but effective ways to lower the risk of respiratory infections. These include frequently washing your hands with normal soap and water, and not touching your face with your hands.

People who already have a respiratory infection can stop it from spreading by throwing away tissues immediately after using them and not shaking hands with other people. (ANI)

Ginkgo extract may help prevent stroke damage

Fri, 10 Oct 2008 04:48:00 -0400

Daily dose of a standardized extract from the leaves of the ginkgo tree can prevent or reduce brain damage after an induced stroke, say researchers.

After working with genetically engineered mice, researchers at Johns Hopkins came to the conclusion.

The study has been published in Stroke.

The scientists say their work lends support to other evidence that ginkgo biloba triggers a cascade of events that neutralizes free radicals known to cause cell death.

"It''s still a large leap from rodent brains to human brains but these results strongly suggest that further research into the protective effects of ginkgo is warranted," says lead researcher Sylvain Dore, Ph.D., an associate professor in the Department of Anesthesiology and Critical Care Medicine.

"If further work confirms what we''ve seen, we could theoretically recommend a daily regimen of ginkgo to people at high risk of stroke as a preventive measure against brain damage,” the expert added.

In the study, researchers gave ginkgo biloba EGb 761 - a lab-quality form of the extract - to normal mice and HO-1 knockout mice, mice lacking the gene that produces the enzyme heme oxygenase-1(HO-1).

HO-1 breaks down heme, a common iron molecule found in blood, into carbon monoxide, iron and biliverdin. HO-1 has been shown to act as an antioxidant and have a protective effect against inflammation in animal models.

Dore and his team gave 100 milligrams per kilogram of EGb 761 extract orally once daily for seven days before inducing stroke in the mice by briefly blocking an artery to one side of the brain.

After stroke induction, the mice were tested for brain function and brain damage. One such test, for example, involves running patterns, another tests reaction to an external stimulus. Similar tests were conducted on mice that did not receive the ginkgo extract.

Neurobehavioral function was evaluated before the study and at 1, 2 and 22 hours after stroke using a four-point scale: (1) no deficit, (2) forelimb weakness, (3) inability to bear weight on the affected side, (4) no spontaneous motor activity.

Results showed that normal mice that were pretreated had 50.9 percent less neurological dysfunction and 48.2 percent smaller areas of brain damage than untreated mice.

These positive effects did not exist in the HO-1 knockout mice.

"Our results suggest that some element or elements in ginkgo actually protect brain cells during stroke," says Dore. (ANI)