Science World

Gene Therapy Treatment Reverses Vision Loss

(Photo: Petr Novák, Wikipedia)

(Photo: Petr Novák, Wikipedia)

Scientists at the University of Pennsylvania may have found a way to prevent, and even reverse, a serious inherited eye disease which leads to blindness.

The disease, called X-linked Retinitis Pigmentosa (XLRP),  causes early, severe and progressive vision loss.

It is one of the most common inherited forms of retinal degeneration in people.

Peoples with XLRP experience a gradual decline in their vision as  the eye’s photoreceptor cells die off.

At first, XLRP usually impacts the ability to see in dimly-lit areas.  Later, sufferers notice a reduction in their visual field,  a sort of  “tunnel vision,” as though they’re looking at things through a narrow tunnel.

Over the years, as the disease advances, the ability to see in even normally-lit conditions, or day vision, progressively dies, leading to complete blindness.

A scene as it might be viewed by a person with retinitis pigmentosa. (Photo: National Eye Institute, National Institutes of Health)

A scene as it might be viewed by a person with retinitis pigmentosa. (Photo: National Eye Institute, National Institutes of Health)

The University of Pennsylvania research was conducted on dogs.

However, the scientists say there are enough similarities between humans and dogs – in terms of eye anatomy, physiology and disease characteristics – that the positive results with gene therapy raise hope of developing similar therapies for humans.

Past research shows XLRP is caused by defects in the RPGR gene.  Scientists discovered a region on the X chromosome, where the RPGR gene is located, which tends to be very susceptible to damage.

Consequently, when there is a replication of cells in a part of the RPGR gene called ORF-15, that replication can be faulty, producing a mutated gene.

To correct or repair the mutated gene, the researchers developed a therapeutic version of it, which is actually a healthy human RPGR gene.

Using a viral vector, a common tool scientists use to deliver genetic material into individual cells which can specifically deliver the therapeutic gene to only the diseased or damaged cells, the researchers were able to repair, not only the damaged photoreceptor cells, but also the connectors which send signals from the photoreceptors to the brain.

Dr. Gustavo D. Aguirre (left) and Dr. William A. Beltran (right) (Photo: University of Pennsylvania School of Veterinary Medicine)

Dr. Gustavo D. Aguirre (left) and Dr. William A. Beltran (right) (Photo: University of Pennsylvania School of Veterinary Medicine)

The researchers call the results of this treatment “dramatic.”

In dogs that already had the disease, scientists   were able to stop the retinal degeneration completely. The previously-damaged cells were able to function normally and scientists were able to prevent XLRP altogether if the retina was treated before the disease had a chance to develop.

The findings of the team’s research were recently published in the journal Proceedings of the National Academy of Sciences.

Dr. Gustavo Aguirre, senior author of the study and the paper’s lead author, Dr. William Beltran,  both of the University Of Pennsylvania School Of Veterinary Medicine, join us this weekend on the radio edition of “Science World.”

They’ll talk about how their findings could help those suffering from X-Linked Retinitis Pigmentosa. Tune in (see right column for scheduled times) or check out the interview below.

[audio://blogs.voanews.com/science-world/files/2012/02/One-On-One-Drs.-Aguerre-and-Beltran-XLRP.mp3|titles=One On One – Drs. Aguerre and Beltran – XLRP]

Other stories we cover on the “Science World” radio program this week include:

Science Scanner: Fear of Terrorists Keeps Man-made Avian Flu Under Wraps

Electron micrograph provided by the U.S. Centers for Disease Control and Prevention shows the bird flu virus strain H5N1 (in gold). (Photo: AP)

Electron micrograph provided by the U.S. Centers for Disease Control and Prevention shows the bird flu virus strain H5N1 (in gold). (Photo: AP)

In December, the U.S. government asked scientists working on a man-made version of the avian flu virus to withhold certain details of their studies out of concern terrorists might use the information to manufacture and spread the dangerous virus, causing a worldwide pandemic.

At the time of the request by the U.S. National Science Advisory Board for Biosecurity, details of the studies into the H5N1 avian influenza virus were under review for publication in the journals Science and Nature.

The journal Science reported last week that the researchers agreed to a 60-day moratorium on some of the more sensitive aspects of their studies involving H5N1 in order “to provide time” for international discussions.

Yesterday, members of the US National Science Advisory Board for Biosecurity offered an explanation for the action they took regarding the controversial H5N1 studies.

“We are in the midst of a revolutionary period in the life sciences. Technological capabilities have dramatically expanded, we have a much improved understanding of the complex biology of selected microorganisms, and we have a much improved ability to manipulate microbial genomes. With this has come unprecedented potential for better control of infectious diseases and significant societal benefit. However, there is also a growing risk that the same science will be deliberately misused and that the consequences could be catastrophic.”

>>> Read more…

NASA’s IBEX looks at space beyond our solar system

Studies of matter from outside of our Solar System reveal an alien environment which contains material riding on the interstellar wind throughout our galaxy that doesn’t look like the same things our own Solar System is made of.

NASA says the new data – from by the Interstellar Boundary Explorer (IBEX) –  provides scientists with insight into not only the origins of our Solar System and the physical powers that went into forming it, but also the history of other stars all over the Milky Way galaxy.

“We’ve directly measured four separate types of atoms from interstellar space and the composition just doesn’t match up with what we see in the Solar System,” says Eric Christian, a mission scientist for the IBEX program at NASA’s Goddard Space Flight center in Maryland. “IBEX’s observations shed a whole new light on the mysterious zone where the Solar System ends and interstellar space begins.”

David McComas, the IBEX principal investigator at the Southwest Research Institute in Texas, believes the findings suggest two possibilities.

“Either the Solar System evolved in a separate, more oxygen-rich part of the galaxy than where we currently reside, or a great deal of critical, life-giving oxygen lies trapped in interstellar dust grains or ices, unable to move freely throughout space.”

>>> Read more…

Developing more effective antibiotics

(Photo: US Food and Drug Administration)

(Photo: US Food and Drug Administration)

Bacterial resistance to antibiotics has become a growing concern within the medical community.  As Doctors continue to prescribe stronger and a wider range of these drugs to their patients, the germs the drugs are supposed to fight are getting wise to their nemesis and are changing in ways to survive making the antibiotics less effective.

One reason for this growing resistance to antibiotics, according to a new study published recently in the journal Nature, is that drug resistant proteins are taking the “good” antibiotics, or inhibitors, out of the cells, allowing them to evolve and mutate as if the drugs weren’t given in the first place.

In their research for the study, scientists at Brandeis University focused on one of these drug transporting proteins called EmrE and how it removes the antibiotic from the infected cells.

“You have a disease and an antibiotic goes into the cells to try to kill it but the protein EmrE takes the antibiotic and transports it out,” says Dorothee Kern, a professor of biochemistry and one of the study’s authors.

Kern adds that a challenge in developing drugs that would stop the protein’s method of transport is that you need to kill specific targets but nothing else.

“The goal would be to find clever ways to stop EmrE from functioning as an exporter while allowing necessary nutrients to remain.”

>>> Read more…

Burmese python killing off mammals in Florida Everglades

Researcher John “J.D.” Willson holds a young Burmese python captured in Everglades National Park. (Photo: Michael Dorcas)

Researcher John “J.D.” Willson holds a young Burmese python captured in Everglades National Park. (Photo: Michael Dorcas)

The Burmese python has become a popular pet for some folks. But many who own these constricting snakes find that as the python gets older, it becomes harder to safely manage and maintain.

In order to quickly rid themselves of the potentially-deadly burden of keeping the snake, some release it into the wild.

The pythons have become quite a problem and are considered an invasive species in Florida’s Everglades.  Joining the snakes let go by their owners, are other pythons which were released from Florida pet shops following 1992’s devastating Hurricane Andrew.

A new study reveals the Burmese python has not only become dramatically plentiful in a widening geographic range in the Florida Everglades Park since 2000, but it has also consumed a wide variety of mammals and birds, with mid-sized mammals being most affected.  Reported sightings of mammals such as raccoons, opossums, white-tailed deer and  bobcats have diminished by as much as 99 percent in areas of the park where the pythons and other similar constricting snakes have been known to frequent.

John “J.D.” Willson from Virginia Tech’s College of Natural Resources and Environment led the study.

“Our research adds to the increasing evidence that predators, whether native or exotic, exert major influence on the structure of animal communities,” he says. ” The effects of declining mammal populations on the overall Everglades ecosystem, which extends well beyond the national park boundaries, are likely profound, but are probably complex and difficult to predict.”

The US National Park Service, which oversees Florida Everglades National Park, reports it has captured and removed 1,825 Burmese pythons since 2000.

>>> Read more…