UPI NewsTrack Health and Science News

Scientist warns of mass ocean extinctions

SAN DIEGO, Aug. 13 (UPI) -- A U.S. scientist says human activities are destroying the world's oceans and only prompt and wholesale changes will avoid catastrophe.

The warning comes from Jeremy Jackson, a professor at the Scripps Institution of Oceanography in San Diego. He says human impacts are laying the groundwork for mass extinctions in the oceans that could equal the vast ecological upheavals of the past.

Jackson says the dire situation has been brought about by the synergistic effects of habitat destruction, overfishing, ocean warming, increased acidification and massive nutrient runoff. He calls the ongoing transformation of once complex ocean ecosystems into simplistic ecosystems dominated by microbes, algal blooms, jellyfish and disease as "the rise of slime."

"It's a lot like the issue of climate change that we had ignored for so long," he said. "If anything, the situation in the oceans could be worse because we are so close to the precipice in many ways."

His assessment of the Earth's oceans and their failing ecological health appears in the online early edition of the Proceedings of the National Academy of Sciences.

Origin of brain tumors in children found

MUNICH, Germany, Aug. 13 (UPI) -- German scientists say they've found the developmental process of medulloblastoma -- one of the most malignant brain tumors among children and teenagers.

In two studies working with international scientific teams, Dr. Ulrich Schuller of Germany's Ludwig Maximilian University discovered the molecular mechanisms that lead to the development of such cerebellar tumors.

The researchers triggered genetic changes in cell populations in the brains of mice to provoke the growth of tumors. They found medulloblastomas arose from only one type of cell -- granule cells -- and only if those cells were fully committed.

"Medulloblastomas are presently treated with non-specific methods," said Schuller. "Our results could contribute to the development of targeted therapies, and thus improve the treatment of cerebellar tumors in children."

The research is reported in the journal Cancer Cell.

Study determines why chili peppers are hot

GAINESVILLE, Fla., Aug. 13 (UPI) -- A U.S.-led international team of scientists has solved a long-standing evolutionary mystery involving the spicy hotness of chili peppers.

University of Florida Professor Douglas Levey, one of the researchers, said a plant creates fruit to entice animals to eat and disperse its seeds. Therefore, said Levey, it doesn't make sense for that fruit to be painfully hot.

Now the study led by Assistant Professor Joshua Tewksbury of the University of Washington has discovered the reason is a fungus called Fusarium, which invades the fruits through wounds made by insects and destroys the seeds before they can be eaten and dispersed.

But capsaicin, the chemical that makes the peppers hot, drastically slows microbial growth and protects the fruit from Fusarium.

"And while capsaicin deters local mammals, such as foxes and raccoons, from consuming the chilies, birds don't have the physiological machinery to detect the spicy chemical and continue to eat the peppers and disperse seeds," Levey said.

The study's findings appear online in the Proceedings of the National Academy of Sciences.

Hepatitis B 'nanovaccine' is developed

ANN ARBOR, Mich., Aug. 13 (UPI) -- U.S. medical scientists say a new "nanovaccine" for hepatitis B that shows promise for use in the developing world has moved closer to human trials.

University of Michigan researchers said the new nanoemulsion eliminates three major problems associated with current vaccines -- the need for refrigeration, difficulty in maintaining needle and syringe sterility and the need for people to return for the three-shot regimen.

Although there are three effective vaccines available, hepatitis B infects 400 million people worldwide, many of them children in Africa, Asia and South America.

But researchers at the University of Michigan's Nanotechnology Institute for Medicine and Biological Sciences at the University of Michigan say their new, needle-free method avoids all three drawbacks and animal tests indicate it provides non-toxic and strong, sustained immune responses.

"Our results indicate needle-free nasal immunization, using a combination of nanoemulsion and hepatitis B antigen, could be a safe and effective hepatitis B vaccine, and also provide an alternative booster method for existing vaccines," said Dr. James Baker Jr., the study's senior author.

Baker said researchers hope the first human trial can begin within a year.

The study is reported in the online journal PLoS One.