Saturday October 20, 2018

To Treat Brain Cancer Scientists Taking Polio’s Help

The result is a longer life for patients whose brain cancer returned

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A radiologist examines the brain X-rays of a patient. In a small study, patients with brain tumors were given genetically modified poliovirus, which helped their bodies attack the cancer.
A radiologist examines the brain X-rays of a patient. In a small study, patients with brain tumors were given genetically modified poliovirus, which helped their bodies attack the cancer. VOA
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There’s an exciting new breakthrough in treating some types of deadly brain tumors, that uses, of all things, a polio virus. Doctors at Duke Health in North Carolina genetically altered the virus because it produces such a strong immune response in our bodies. The result is a longer life for patients whose brain cancer returned. All had glioblastoma, an aggressive and lethal type of brain cancer. Of the 61 patients in the study, 21 percent who got this new treatment had were alive three years later.

While that number is low, the survival rate for glioblastoma is normally even lower, usually, a year and a half after diagnosis. The researchers compared the study group to a group of patients drawn from historical cases at Duke. Only four percent of these patients survived three years after treatment.

Dr. Annick Desjardins, one of the authors, said not all patients respond, but if they do, they often become long-term survivors. Desjardins said, “The big question is, how can we make sure that everybody responds?”

Stephanie Hopper was the first patient in the Duke study. She was diagnosed with glioblastoma eight years ago. She had the tumor removed, but two years later, it returned. The modified virus is directly injected into the brain during surgery. After treatment, Hopper’s tumor shrunk to the point where it’s barely noticeable in her brain scans, and the tumor is continuing to shrink.

Dr. Darell Bigner is the senior author of the study which was published in the New England Journal of Medicine. He explained that by modifying the virus, it destroyed its ability to infect nerve cells and cause polio, but the virus retained the ability to kill cancer cells. In fact, the modified virus targeted the tumor cells.

Prior to the study, the researchers decided they needed a different approach to treating glioblastomas which is why they looked at experimenting with the polio virus.

There's an exciting new breakthrough in treating some types of deadly brain tumors, that uses, of all things, a polio virus. Doctors at Duke Health in North Carolina genetically altered the virus because it produces such a strong immune response in our bodies
There’s an exciting new breakthrough in treating some types of deadly brain tumors, that uses, of all things, a polio virus. Doctors at Duke Health in North Carolina genetically altered the virus because it produces such a strong immune response in our bodies. Flickr

One of the goals of a phase one trial is to find a dose that is safe. In some patients, the therapy caused their brains to swell and they experienced seizures and other bad side effects so the dose was lowered. Study participants were selected according to the size of their recurring tumor, its location in the brain and other factors designed for patient protection.

For five of the 61 patients in the trial, the cancer returned. They were treated a second time and Bigner says, “Those that we’ve been able to follow long enough have responded to the treatment the second time. That’s extremely important.” Combining the polio virus with other approved therapies is one approach already being tested at Duke to improve survival.

Also read: A One-Shot Nanoparticle Vaccine for Polio is Developed by MIT scientists

The researchers are continuing their work on treating glioblastomas and planning other studies as well. They want to test the therapy on children’s brain tumors. The therapy may also expand beyond brain tumors to include breast cancer and melanoma patient as well. (VOA)

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Invasive Species May Not Be All Bad: Scientists

An active debate among biologists about the role of invasive species in a changing world is going on

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Invasive Species
The invasive European green crab is tearing down ecosystems in Newfoundland and building them up on Cape Cod. VOA

Off the shores of Newfoundland, Canada, an ecosystem is unraveling at the hands (or pincers) of an invasive crab.

Some 1,500 kilometers (930 miles) to the south, the same invasive crab — the European green crab — is helping New England marshes rebuild.

Both cases are featured in a new study that shows how the impacts of these alien invaders are not always straightforward.

Around the world, invasive species are a major threat to many coastal ecosystems and the benefits they provide, from food to clean water. Attitudes among scientists are evolving, however, as more research demonstrates that they occasionally carry a hidden upside.

“It’s complicated,” said Christina Simkanin, a biologist at the Smithsonian Environmental Research Center, “which isn’t a super-satisfying answer if you want a direct, should we keep it or should we not? But it’s the reality.”

Simkanin co-authored a new study showing that on the whole, coastal ecosystems store more carbon when they are overrun by invasive species.

Good news, crab news

Take the contradictory case of the European green crab. These invaders were first spotted in Newfoundland in 2007. Since then, they have devastated eelgrass habitats, digging up native vegetation as they burrow for shelter or dig for prey. Eelgrass is down 50 percent in places the crabs have moved into. Some sites have suffered total collapse.

That’s been devastating for fish that spend their juvenile days among the seagrass. Where the invasive crabs have moved in, the total weight of fish is down tenfold.

The loss of eelgrass also means these underwater meadows soak up less planet-warming carbon dioxide from the atmosphere.

In Cape Cod, Massachusetts, the same crab is having the opposite impact.

Off the coast of New England, fishermen have caught too many striped bass and blue crabs. These species used to keep native crab populations in check. Without predators to hold them back, native crabs are devouring the marshes.

But the invasive European green crab pushes native crabs out of their burrows. Under pressure from the invader, native crabs are eating less marsh grass. Marshes are recovering, and their carbon storage capacity is growing with them.

Invasive species
In this May 8, 2016 photo, eelgrass grows in sediment at Lowell’s Cove in Harpswell, Maine. VOA

Carbon repositories

Simkanin and colleagues compiled these studies and more than 100 others to see whether the net impact on carbon storage has been positive or negative.

They found that the ones overtaken by invasive species held about 40 percent more carbon than intact habitats.

They were taken by surprise, she said, because “non-native species are thought of as being negative so often. And they do have detrimental impacts. But in this case, they seem to be storing carbon quicker.”

At the Smithsonian Environmental Research Center where she works, the invasive reed Phragmites has been steadily overtaking a marsh scientists are studying.

Phragmites grows much taller, denser and with deeper roots than the native marsh grass it overruns.

But those same traits that make it a powerful invader also mean it stores more carbon than native species.

“Phragmites has been referred to as a Jekyll and Hyde species,” she said.

Not all invaded ecosystems stored more carbon. Invaded seagrass habitats generally lost carbon, and mangroves were basically unchanged. But on balance, gains from marsh invaders outweighed the others.

Invasive species
Phragmites plants growing on Staten Island draft in a breeze in the Oakwood Beach neighborhood of Staten Island. VOA

Not a lot of generalities

To be clear, Simkanin said the study is not suggesting it’s always better to let the invaders take over; but, it reflects an active debate among biologists about the role of invasive species in a changing world.

“One of the difficult things in the field of invasion biology is, there aren’t a lot of generalities,” said Brown University conservation biologist Dov Sax, who was not involved with the research. “There’s a lot of nuance.”

The prevailing view among biologists is that non-native species should be presumed to be destructive unless proven otherwise.

When 19 biologists wrote an article in 2011 challenging that view, titled, “Don’t judge species on their origins,” it drew a forceful rebuke from 141 other experts.

Sax said the argument is likely to become more complicated in the future.

Also Read: Climate Change Not A Hoax: Trump

“In a changing world, with a rapidly changing climate, we do expect there to be lots of cases where natives will no longer be as successful in a region. And some of the non-natives might actually step in and play some of those ecosystem services roles that we might want,” he said.

“In that context, what do we do? I definitely don’t have all the answers.” (VOA)