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22 May 2009
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This week on Our World: Astronauts complete repairs on the Hubble Space Telescope ... A promising new approach to an AIDS vaccine ... and scientists have a nose for a deadly bug's weak spot ...
VOSSHALL: "Mosquitoes are really smart. They pay attention to carbon dioxide exhaled in our breath. They're very sensitive to human body odor smells. So all of those things help them figure out it's a living, breathing, alive human."
And if mosquitoes don't smell you, they won't bite you. Lots more on our show this week.
I'm Art Chimes. Welcome to VOA's science and technology magazine, "Our World."
Shuttle astronauts complete Hubble repairs, upgrades
Astronauts aboard the space shuttle Atlantis this week completed a series of repairs and upgrades to the Hubble Space Telescope.
On Wednesday, during an in-flight news conference, veteran Hubble repair guy John Grunsfeld voiced satisfaction with the job they did, giving the space telescope a new lease on life.
GRUNSFELD: "You know, we really did it. We had all of the upgrades and repairs that we meant to do, and Hubble was going off on its voyage of discovery. What we've done up here is give Hubble five or perhaps even 10 more years of life. So we're going to see a lot of Hubble every single day, and that's what we're really excited about."
This mission almost didn't happen. After the shuttle Columbia broke up as it was returning from space in 2003, NASA adopted stricter safety rules and decided it was too dangerous to fly to the Hubble. In case of trouble, the astronauts wouldn't be able to reach the safe haven of the space station.
In the end, astronomers convinced NASA it was worth the risk. But before that, NASA explored the idea of sending a robotic spacecraft to do the Hubble repairs. Astronaut Grunsfeld, who was involved in ground-testing the concept, said the unexpected challenges they've experienced in working on the space telescope, which required some unplanned improvisations, underscores the value of having humans on the job.
GRUNSFELD: "Many of the things that we did were not possible robotically. And I think that's the real utility of humans is we're able to deal with situations that are the unexpected. We do that all day long. It's one of the amazing capabilities of the human brain, and you know Hubble had enough surprises in here that I think a robotic mission would have been very difficult."
The next space shuttle flight is set for mid-June, with Endeavour heading for the International Space station carrying seven astronauts and a payload of Japanese scientific instruments.
Researchers develop novel HIV vaccine
Here on Earth, U.S. researchers have developed an experimental vaccine against the virus that causes AIDS. They are using a novel technique that leapfrogs the body's natural immune system. It's still years away from human use, but the new vaccine has been successfully tested in monkeys, as VOA's Jessica Berman reports.
BERMAN: Dr. Philip Johnson and a team of researchers at Children's Hospital of Philadelphia and the University of Pennsylvania School of Medicine decided to pursue their novel approach because, Johnson says, all previous efforts to get the body's natural immune system to fight off an HIV infection have failed:
JOHNSON: "I think that the time has passed and people have seen that the traditional methodologies, the traditional approaches, have not worked. And there's no evidence that they will work in the short term."
Instead, Johnson and his colleagues pursued a strategy they've been working on for ten years that focuses on special antibody-like proteins that can neutralize the HIV virus.
Bypassing the immune system, the investigators created the proteins from a simian variant of HIV called SIV, which infects monkeys. They engineered the DNA of these proteins into a harmless cold virus and injected this modified carrier into the muscles of laboratory monkeys that were not infected with SIV.
Once injected into the muscles, the transferred genes began producing and pumping out anti-SIV proteins - called immunoadhesins - that circulated throughout the monkeys' bloodstream, binding to SIV and preventing the virus from infecting healthy cells.
In order to produce a vaccine for humans, Johnson says researchers would make immunoadhesins from people who have been infected with HIV for decades, in some cases before they developed AIDS.
JOHNSON: "And what we can do is go into those individuals, take cells from them and then actually tease out the genes that are responsible [for keeping AIDS at bay]. And then we can use those genes to develop new molecules in the lab that we can then turn around and give back to people who have never been exposed to HIV. And in the case of the monkey study that we just published on, we were able to protect the monkeys from infection using that approach."
The study, published in the journal Nature Medicine, involved nine rhesus macaques that were injected with the modified SIV immunoadhesins.
When they were injected with live SIV four weeks later, six of the monkeys were completely protected from infection. And researchers found that more than a year later, all of the monkeys still had high concentrations of the antibodies in their blood.
By contrast, a group of six unimmunized monkeys became infected with SIV, and four of them died during the experiment from AIDS complications. The three immunized monkeys infected with SIV never developed AIDS.
Seth Berkley, president and founder of the International AIDS Vaccine Initiative, says the SIV vaccine represents an important milestone.
BERKLEY: "We're not sure this is ultimately going to be a vaccine. But if we can take this approach and show protection, that gives you a proof of concept, and nothing would be more important to the field than having that proof of concept, and also being able to set the levels of antibody required and understand the correlates of protection."
Meanwhile, Dr. Philip Johnson and his colleagues plan to meet soon with U.S. Food and Drug Administration regulators to work out the details of human vaccine trials, which could begin within the next two years. Jessica Berman, VOA News, Washington.
Controlling disease by targeting the mosquito's nose
Scientists use the term "vector" to describe an organism that transmits disease. Perhaps the most dangerous vector is the mosquito, which feeds on human blood and in the process spreads a variety of deadly diseases. Insecticides like DDT have been used to kill the bugs, and bed nets can keep them from transmitting disease. But scientists are on the lookout for new ways to battle this age-old pest.
Dr. Leslie Vosshall, a researcher at Rockefeller University in New York, has been working on new approaches to insect repellents, which could lead to new weapons in the fight against malaria and other killer diseases. As you'll hear, she's focusing on the insect's well-developed sense of smell.
VOSSHALL: "Mosquitoes are important because they have evolved a really strong attraction to humans, and when they bite us they can transmit deadly infectious diseases like malaria, dengue, and West Nile, and Yellow Fever."
Q So what are the strategies that can be employed to try to keep mosquitoes at bay?
VOSSHALL: "A number of strategies have been tried. So the old fashioned strategy of killing the mosquito with insecticides or larvicides. We're interested in newer technologies to repel insects, either with personal protectants that repel mosquitoes or spatial repellents you can put in your home so mosquitoes don't come in in the first place."
Q: We've got some products like that on the market now; what's the problem with them? And maybe you can talk about the different ones that might be available in different parts of the world.
VOSSHALL: "So yes, there are products that work as repellents. DEET is widely in use as an insect repellent in the U.S. and Canada. Picaridin is widely in use in Europe. And both of these products and others like them on the market, you apply them to your body or your clothing and insects don't bite you. So that's an interesting and effective strategy. Our scientific interest [in our lab] is in trying to understand how those existing compounds work and then improve upon them using the science of smell.
Q: Let's step back a bit. How does the mosquito find us to bite us?
VOSSHALL: "Mosquitoes are really smart. They take lots of information into account. So they pay attention to carbon dioxide exhaled in our breath. They're very sensitive to human body odor smells. And they can probably also sense our body heat. So all of those things, plus visual cues, together help them figure out it's a living, breathing, alive human."
Q: Here in the United States and in a lot of other countries DEET is sort of state of the art as a repellent, but it's an old product. What are the problems with it?
VOSSHALL: "DEET was launched for work in the consumer market in the mid-1950s, developed in the Second World War for military use, and it's quite effective. Nothing has come along in the last 50 years to improve upon it.
"The problems with it are that you have to put on extremely high concentrations, it feels very oily on the skin, and it's not safe for use on young children. And so in disease endemic areas, DEET is essentially useless as a tool for preventing disease transmission."
Q: And young children are the ones most at risk for malaria, for example.
VOSSHALL: "Malaria deaths are highest in children under four, so this is the sensitive population; we'd like to prevent mosquitoes from getting at those babies."
Q: So as a scientist, understanding that smell is a big part of what mosquitoes are doing, what is you approach in your lab?
VOSSHALL: "So, we're molecular biologists and we've done a lot of work trying to understand the basic mechanisms by which mosquitoes and other insects smell odors. We have a really good handle on that. Our lab and many other laboratories have contributed to deep understanding of the proteins that allow insects to smell. We think we can now take that to an applied focus, to come up with new chemical molecules that will inhibit insect smell - very selectively block the ability of mosquitoes to smell humans. We think those have the potential to be safer and more effective than DEET."
Q: If you understand this on a genetic level, people are going to wonder, well why don't you approach it from a genetic level - one in terms of some sort of genetic manipulation of the mosquito population.
VOSSHALL: "That's an interesting idea in the laboratory and it's something we're trying in the laboratory, but there's a catch-22 there because mosquitoes need to smell to be able to reproduce. So if you make a race of mosquitoes that's unable to smell, it probably wouldn't fare well in the natural world. It wouldn't be able to reproduce."
Q: But does that genetic knowledge help you in your work, in developing models, for example?
VOSSHALL: "Yes, absolutely. We use genetics extensively to be sure that we're working on the right proteins, and when we disrupt a protein important in smell, and we see that the insect is no longer able to respond to odor cues, then we know we're on the right track."
Q: What's the goal? Is it a product that you would slather on your skin?
VOSSHALL: "Well, the goal is to do the basic research that brings us just to the threshold of development, of coming up with compounds that show really good efficacy in the laboratory, and then find a commercial partner that can develop this into a safe product. You can imagine using traditional routes like sprays and creams, which is what people use now. Or packaging it into a physical matrix that could then be hung in a door or worn, so you wouldn't have to spread it on your skin. I sort of favor those slow-release ideas more."
Q: How do you guarantee that a product is going to be affordable to the people who are going to really need it, who don't have a lot of money?
VOSSHALL: "Our work is funded by the Bill and Melinda Gates Foundation, and that's part of the goal of the project, is to, when selecting potential molecules, look to those that are going to be chemically simple enough that we can make something that's realistically affordable for developing world clients."
Dr. Leslie Vosshall of Rockefeller University. I spoke with her on Capitol Hill at an event sponsored by the Congressional Biomedical Research Caucus.
We'll have more health news later in the show, but first ...
A new kind of Internet search on our Website of the Week
It's time again for our Website of the Week, when we showcase interesting and innovative online destinations.
Many of us have become accustomed to using the Internet as a kind of reference library. Want to know the population of Cairo or the distance from the Earth to the Moon? Plug your question into Google or another search engine, and you'll be directed to other websites where you might find the answer.
At Wolfram Research, the company that publishes the powerful Mathematica software, they have a different approach to finding answers on a new website they introduced on Monday [May 18].
WEISSTEIN: "Wolfram Alpha is a computational knowledge engine. It's not a search engine, but rather a way to search kind of the computational universe. So it knows all about facts, figures, and it can do sorts of queries that traditional search engines have difficulty with."
Eric Weisstein is a senior researcher at Wolfram who has been working on their latest project, WolframAlpha.com. Unlike conventional search engines, Wolfram Alpha returns answers from its own database, which has been reviewed for accuracy.
WEISSTEIN: "So we have gone out and found the best data sources available and collected it all together and done various analyses on it to try to ensure that it's as correct and complete as possible."
So far at least, Wolfram Alpha is great at certain kinds of queries. Population of Cairo? 7.7 million. Distance from Earth to the Moon? 381,000 kilometers.
It's not the right tool for everything, though. No luck when I tried "hummus recipe," or - I'm sorry to report - "Voice of America." But if there are numbers involved, Wolfram Alpha may have the answer, along with comparisons and computations that the sophisticated Mathematica software makes possible.
WEISSTEIN: "We probably have somewhere on the order of a trillion individual pieces of information. Of course, because Wolfram Alpha is built on Mathematica, and Mathematica knows how to do all sorts of mathematical problems, in actuality of course, there's an infinite number of things you can do."
A new way of searching for information at WolframAlpha.com, or get the link to this and some 250 other Websites of the Week from our site, VOAnews.com/ourworld.
MUSIC: Paul Winter - "Aula de Matemática" (A Mathematics Lesson)
It's VOA's science and technology magazine, Our World. I'm Art Chimes in Washington.
5D storage model could put 300 movies on DVD-size disk
Researchers in Australia say they have developed a way to dramatically increase the storage capacity of a DVD-size disk.
If it all works out you could watch a different movie almost every night of the year, and never have to change disks.
James Chon and colleagues at Swinburne University of Technology say the new idea takes a multi-layer disk, where bits of data are stored in two surface dimensions plus depth, and combines it with coding for two other factors
CHON: "Individual bits can have different colors of encoding schemes and have three more additional 'layers,' so to speak. Now going to five-dimensional storage, now, we can add further another dimension in recording, which is the polarization encoding, one horizontal and one vertical. So in total, we can have six additional channels in one recording bit."
In this five-dimension configuration the disk could hold about 1.6 terabytes of data - about as much as 300 DVDs.
Dr. Chon says a prototype is still three to five years away. He describes the new super-dense storage disk concept this week in the journal Nature.
Leading NGOs call for action against chronic disease
Most people think that diseases such as such as diabetes, cancer, and heart disease mainly affect wealthy countries. Not exactly. The World Health Organization, in fact, reports that cardiovascular disease is the world's number one killer.
Several disease advocacy groups came to the WHO recently to ask that more attention be paid to these diseases in developing countries. More from health reporter Rose Hoban.
HOBAN: In developing countries, infectious diseases such as tuberculosis, AIDS and malaria create a tremendous burden on society. But chronic diseases also create suffering for many people - in both wealthy and low income countries. Martin Silink heads the International Diabetes Federation. He says the number of people around the world with conditions like diabetes, heart disease and cancer is growing rapidly.
SILINK: "It's thought now - and the estimates are really very good - that six percent of the adult population of the world has this form of diabetes, type 2 diabetes. And it's growing at the rate of 7 million more each year."
HOBAN: As people start to live longer and more prosperous lives, they are more prone to chronic diseases. Silink says this is becoming evident as more people migrate to cities. Since 2007, more people in the world are living in cities than in rural areas.
SILINK: "And this migration from the country to the cities is still occurring. There is very good information that shows that if you move from a rural, country location to the city, then you double your risk for diabetes. If the city is more than a million people in size, you double it again. And if it is a mega-city of more than 10 million, you double your risk of diabetes again."
HOBAN: But Silink says organizations like the World Health Organization and large donors tend to focus on communicable diseases. They don't fund research or treatment for chronic diseases.
SILINK: "It turns out that there is a only about a list of 10 very simple drugs that are all out of patent and they can be manufactured very, very cheaply. And all it needs is for a political commitment to make these cheap drugs available to this enormous burden of non-communicable diseases in the developing world."
HOBAN: So, Silink and other health care leaders went to Geneva this past week to ask the World Health Organization to increase funding and attention to chronic diseases such as high blood pressure, diabetes and cancer.
SILINK: "You cannot divide a person into a communicable and not communicable. It turns out that this person with tuberculosis may well have diabetes. The person with HIV/AIDS will develop heart disease."
HOBAN: Silink says donors and international organizations need to focus more on strengthening health systems, not just providing funds for the eradication of one disease or another.
Silink made his presentation to the World Health Organization in Geneva this past week. I'm Rose Hoban.
Fewer children dying in poor countries
And also from Geneva, some good news from the WHO. It says there has been a sharp drop in the number of deaths among children under age five. According to its just released report, World Health Statistics 2009, deaths among the under-five age group are down about one-quarter from 1990 to 2007, the last year for which they have final numbers. Lisa Schlein reports from Geneva.
SCHLEIN: The World Health Statistics Report shows about nine-million children died in 2007 compared to 12.5 million in 1990.
It says an estimated 37 percent of deaths among children occur in the first month of life, and most in the first week of life. It says most infant deaths happen in regions where maternal mortality rates are the highest.
Coordinator in WHO's department of Health Statistics and Informatics, Carla Abou-Zahr, says there are a whole range of issues that hold countries back.
ABOU-ZAHR: "Usually there are very weak institutions in many of these countries. Many of them are emerging from conflicts ... And, sub-Saharan Africa in particular, especially in Eastern and Southern Africa are facing major problems of HIV."
SCHLEIN: But Abou-Zahr hastens to add that countries in Africa do not present a uniformly bleak picture. For instance, she says signs of improvement can be seen in places such as Tanzania and Rwanda.
The report argues building a health system that is efficient and really works is not purely a financial matter. Many elements are involved.
But WHO Health Statistics and Informatics Department Director Ties Boerma says money talks when it comes to providing good health.
BOERMA: "If we look at per-capita health expenditure, in the low income countries, it is $22 per capita. In the high-income countries, it is $4,012. Another one. In Africa, there are two doctors for 10,000 people. In the European region, there are 32 doctors for 10,000 people."
SCHLEIN: In one of its many statistical graphs, the WHO study shows money can mean the difference between life and death. It notes three out of 1,000 children under age five die in Iceland, Sweden and Finland compared to 262 child deaths per 1,000 live births in Sierra Leone. Lisa Schlein for VOA News, Geneva.
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