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This week on "Our World" ... How some diabetes patients live normal lives ... a disadvantage for traveling athletes ... and measuring the oceans as the world gets warmer ...
WILLIS: "That causes glaciers to melt. But also, the ocean itself absorbs heat, and when that happens, again the water expands, and this causes sea level rise as well."
A new satellite will keep track ... some hopeful news on an illness that kills millions each year, and more. I'm Art Chimes. Welcome to VOA's science and technology magazine, "Our World."
Researchers at the University of Texas say they have found a chemical compound that may lead to a new treatment for various kinds of diarrheal illness.
Diarrhea is a major health issue in developing countries. The World Health Organization says it kills as many as two and a half million children a year.
The standard treatment for diarrheal diseases in much of the world has shortcomings, says Prof. Ferid Murad.
MURAD: "People in third world countries with infectious diarrheas are given a packet of sugars and amino acids and salts mixed in water to drink. And that's much more effective, but you're still having to deal with fresh, clean water, which can be a problem in some of those countries. So while it's helping, it's not optimal."
Dr. Murad was awarded the Nobel Prize in 1998 for research on how nitric oxide transmits information from cell to cell in the body's cardiovascular system.
His interest in the body's so-called signaling mechanisms led him to search for a chemical that could stop diarrhea by slowing down the transmission of information from cell to cell within the intestine.
In the Proceedings of the National Academy of Sciences, Murad says he has found just such a chemical.
He said it is a previously-discovered but unused compound known as BPIPP, which he found in the inventory of one of the companies where he worked as a consultant.
MURAD: "And some of these companies had a huge inventory of chemicals. And I asked if I couldn't have them to test to see if we could find a molecule that might block this pathway. And that's how it got started about five years ago. And yes, indeed, we found a molecule that blocked that pathway."
Tests using laboratory animals indicate that BPIPP is effective in suppressing diarrhea itself. That's different from the way the oral rehydration therapy works, which is by replacing the fluid loss.
BPIPP is still years away from human use. It will be at least a couple of years before it can be even tested in people and approved.
MURAD: "But I think this compound, should it become a drug, will have a much greater contribution and perhaps can save millions and millions of lives."
Oral rehydration therapy remains the treatment of choice for diarrheal diseases in developing countries, in part because they can be used regardless of the cause, and they are cheap.
Other diarrhea treatments are being developed, but Murad says they are specific to one bacterium and not the general-purpose anti-diarrhea medicine that BPIPP should be.
MURAD: "They may work, but they're not going to be foolproof and shotgun [approach] for a variety of causes of the diarrhea, while this compound, I think, could really be the broad spectrum for bacterial diarrhea."
In addition to use in developing countries, BPIPP may be useful in treating travelers' diarrhea, which affects millions of people each year, though usually not fatally.
Next, two stories about an increasingly common disease, diabetes. Despite advances in medicine and technology, it still disables and kills many who suffer with it. In a moment, we'll hear about efforts to understand why some people manage to thrive despite having the disease. But first, we hear from health reporter Rose Hoban about a new study on the link between diabetes and a common mental health issue.
HOBAN: Around the world, rates of diabetes are on the rise. The disease is marked by high blood sugar that, over the long term, negatively affects other parts of the body — especially the kidneys, heart, and eyes. And some research has noted that people with diabetes are almost twice as likely to also have symptoms of depression.
Dr. Sherita Hill Golden from the Johns Hopkins University wanted to explore this phenomenon. She was interested in seeing if having diabetes can lead to developing depression, or whether being depressed makes it more likely a person will develop diabetes. So, she used data from a large study that included more than 5,000 people.
GOLDEN: "In the first analysis, we were trying to ask the question, does having elevated symptoms of depression lead to type 2 diabetes? And in that analysis, we excluded people who had diabetes initially. And then we looked at those with and without elevated symptoms of depression, and we found that people who had elevated symptoms of depression were 42 percent more likely to develop type 2 diabetes over follow-up."
HOBAN: Then Golden looked at people who were being treated for diabetes to see if they were more likely to develop depression.
GOLDEN: "The people who had treated diabetes were 52 percent more likely to develop symptoms of depression over follow-up in our study, but interestingly, people who had pre-diabetes and untreated diabetes were about 20 percent less likely to develop symptoms of depression."
HOBAN: Golden says she found it interesting that people who had diabetes but didn't know it were less likely to be depressed. She proposes that the reason for the link between diabetes and depression is more emotional than physiological.
GOLDEN: "People who are taking medications for diabetes, may also have to monitor their sugar and health behaviors much more intensely than people who don't carry a diagnosis. And so just the burden of the monitoring may lead to risk of depressive symptoms."
HOBAN: Golden says patients with depression had worse health behaviors — they smoked and ate more, and they weighed more and exercised less. All those behaviors contribute to developing diabetes. She also says there might be some connections between increased stress hormones in people with depression and the development of diabetes. Golden says that will be an area for further study.
Her research is published in JAMA — the Journal of the American Medical Association. I'm Rose Hoban.
As many as 24 million people worldwide have type 1 diabetes, also known as juvenile diabetes. It's an autoimmune disease, which results in the total inability to make insulin, which the body needs to survive. VOA's Rosanne Skirble takes a closer look at why some people are living longer than others with the disease.
SKIRBLE: Maureen Murray was diagnosed with juvenile diabetes when she was 12 years old. It was 1954, and Murray says that began a life-long battle to control her blood sugar levels.
MURRAY: "You would take the insulin. You would have no idea what your blood sugars were. You had urine tests that were not that effective, and you literally didn't know where [your blood sugar levels] were."
SKIRBLE: Over the next 33 years, Maureen Murray repeatedly tested her urine and injected a dose of insulin many times a day. The process became easier in the mid-1980s, when the insulin pump and a glucose blood-testing machine became available. The pump mimics the pancreas and delivers insulin through plastic tubing inserted in her stomach. Extra insulin is programmed for meals.
MURRAY: "Just the insulin that your body needs to maintain life."
SKIRBLE: Murray now wears a sensor embedded under her skin and carries a receiver that monitors blood sugar levels every five minutes. The information eliminates the need for multiple physical blood tests each day.
MURRAY: "It's automatic, but maybe every 10 days you have a mini-breakdown [laughter]. It is automatic and it is such a pleasure to be able to use this equipment, but it is exhausting."
SKIRBLE: While all this may seem complicated, Murray says the new medical tools have made her life much easier. Murray sums up how she cares for herself this way:
SKIRBLE: Murray has had no diabetic complications in 53 years. But her case is rare. She credits her good health to an active lifestyle, family and friends. She also holds down a full time job, keeps physically fit and eats well.
Murray has a lot in common with the 326 men and women who participated in the Joslin Diabetes Center Medalist study, presented at the Juvenile Diabetes Foundation annual Conference last week.
KING: "They are not overweight. They are not smokers. [They] exercise frequently, and lack evidence for micro-vascular complications."
SKIRBLE: Joslin Director of Research George King is the lead author of the study that compared physiological, clinical, and genetic data for people who have been insulin dependent for 50 years or more.
KING: "About thirty percent of these individuals don't have any eye disease, kidney disease or nerve disease even after 50 years of diabetes. If we could activate whatever there in all diabetic patients, then essentially we could either stop or prevent diabetic complications in all diabetic patients."
SKIRBLE: King says the most remarkable finding was that the participants still had measurable levels of C-peptide, a protein fragment released by the pancreas, and a sign of insulin-producing islet cells.
KING: "If you look at those patients between 50 and even 70 years with diabetes, quite a few, about 20 percent of them, clearly have C-peptide, which suggests that they are making insulin."
SKIRBLE: King says the findings open new avenues for research and treatment of Type-1 Diabetes.
All this is good news to Maureen Murray, who hopes that she can live long enough to see a cure. When asked whether or not she would donate her pancreas to science when she dies, the answer was obvious.
MURRAY: " I said, 'Of course!' And I thought to myself, don't we all want to be remembered for something in our life? And if I could better the world by giving my pancreas to research, I couldn't think of anything more rewarding [to do]."
SKIRBLE: Researchers at the Joslin Diabetes Center are currently recruiting 300 more long-time juvenile diabetes survivors for phase II of the study. I'm Rosanne Skirble.
Time again for our Website of the Week, when we showcase interesting and innovative online destinations.
This week it's a site that highlights some of the greatest creations of human builders: the buildings and dams and bridges and other structures that are landmarks of civil engineering. They're featured on the history and heritage pages of the American Society of Civil Engineers website at asce.org/history.
The main attraction is information about almost 250 landmark projects in thousands of years of civil engineering history, including famous ones like the Brooklyn Bridge in New York and Machu Picchu in Peru, but also lesser known structures like the Pelton Impulse Water Wheel in California and the Woodhead Dam in South Africa.
PETROSKI: "They're at least 50 years old. They must have had some significant advance in civil engineering associated with them. And they must also have a significant impact when they were built so they opened up new ways of doing things or had a very strong influence on the economic vitality of a region."
Duke University professor Henry Petroski chairs the American Society of Civil Engineers committee on history and heritage. Their website also features the 10 civil engineering achievements considered to have had the greatest positive impact on life in the 20th century.
PETROSKI: "Over a century, there was a great deal of advance in technology, but that wasn't for technology's sake. It was really to make life more comfortable, to give people more freedom of movement. Something like the Interstate Highway System in the United States made it very, very convenient for people to go from place to place."
Other so-called "Monuments of the Millennium" include long-span bridges, sanitary landfills, and water supply and distribution.
Also on the civil engineering history website, you can learn about the Seven Wonders of the Modern World including Europe's Channel Tunnel, San Francisco's Golden Gate Bridge, and the Panama Canal, where American engineers took over a failed French project and completed it, thanks to significant advances in engineering —
PETROSKI: "Largely in organization and movement of materials, and also in conquering the disease problem. The canal was completed in 1914, and to this day is really one of the greatest achievements, civil engineering achievements of all time."
To learn more about these and other great examples of civil engineering, point your browser to asce.org/history, or get the link to this and more than 200 other Websites of the Week from our site, voanews.com/ourworld.
We're engineering a better radio experience here at VOA's science and technology magazine, Our World. I'm Art Chimes in Washington.
This week, the U.S. space agency NASA launched its latest satellite — aimed, not at exploring space, but at getting a better understanding of life here on Earth.
The Ocean Surface Topography Mission, or OSTM, also known as Jason 2, blasted off before dawn on Friday aboard an unmanned Delta II rocket from Vandenberg Air Force Base in California.
The satellite's main scientific instrument is a radar altimeter. It will measure sea level by sending radio waves down to the ocean surface and timing how long they take to bounce back.
Previous ocean science satellites have found that sea level is rising at a rate of three millimeters a year.
Josh Willis of NASA's Jet Propulsion Laboratory in California says scientists think they know what is behind the rise.
WILLIS: "This is a direct result of increasing the temperature of the atmosphere. That causes glaciers and ice sheets to melt, raising the level of the ocean. But also, the ocean itself absorbs heat, and when that happens, again the water expands, stands a little taller, and this causes sea level rise as well. So OSTM or Jason 2 will see both of these effects as it circles the Earth."
A sea level rise of three millimeters a year doesn't sound like much, but the mission's project scientist, Dr. Lee Lueng Fu, says that is twice the rate of sea level rise as measured by tide-gauge data collected over the previous century.
FU: "The question facing us [is] whether this apparent acceleration is a real trend caused by global warming, or it is simply just part of a natural variability of our climate system. We don't really know the answer. That's why we need continuing satellite measurement like OSTM/Jason 2 to extend this data record into the future."
The OSTM/Jason 2 satellite is mainly aimed at collecting data for scientific research, not for short-term weather forecasting. But Laury Miller of the U.S. weather agency NOAA says it may also help forecasters get out the word earlier when severe storms are brewing.
MILLER: "The idea is based on the notion that hurricanes feed off of heat energy. And when they come into areas of the oceans where there's an anomalously large amount of heat energy, they intensify even more. And the satellite altimeter can see these locations because in areas where there's a lot of heat energy, the water stands higher due to thermal expansion."
So when the satellite detects an area of higher sea level in the path of a storm, it could be a warning that the storm will get stronger.
OSTM/Jason-2 is a collaboration between the U.S. and French space agencies, and the European weather satellite organization, EUMETSAT.
On Wednesday, U.S. officials said American motorists drove 2.2 billion kilometers less in April than they did in the same month last year.
With oil prices in record territory, drivers are getting more and more conscious of how much fuel they're burning, and what it's costing them.
As a result, some drivers are switching to smaller, more fuel-efficient cars. But many American families have two or more cars. So sometimes the question is, which one to replace to get the most savings.
And according to researchers at Duke University in North Carolina, the answer could often be wrong, because of how Americans customarily measure fuel efficiency — in miles per gallon. A higher number is more efficient. In most other countries, the standard benchmark is liters per 100 kilometers, in which case a lower number is better.
But Rick Larrick of Duke's business school thinks it's more complicated than that. Consider a family with two cars, an SUV and a sedan. They're considering replacing one or the other with a vehicle that gets twice as many miles per gallon. Trading in old 10-mile-per-gallon SUV for one that gets 20 miles per gallon sounds pretty good, but not as good as giving up the 25 mile-a-gallon sedan for a 50 mile per gallon hybrid.
But do the math: the old SUV uses 10 gallons to go 100 miles; the new one, twice as efficient, uses just five. Savings: 5 gallons. The old sedan gets 25 miles per gallon.
LARRICK: "That car's only using four gallons to go 100 miles, and the hybrid's only going to be using two gallons to go 100 miles. That's just a two-gallon saving. The big savings comes from getting rid of the most inefficient car, the SUV that gets 10 miles per gallon with one that's more efficient, the one that gets 20 miles per gallon."
Writing this week in the journal Science, Larrick describes a survey confirming that if the goal is saving fuel, it's easy to get confused by efficiency numbers given in miles per gallon. He also says that when 40- or 50-mile-per-gallon cars are held out as the gold standard, replacing a 'gas guzzler' with a slightly more fuel-efficient vehicle looks like a "drop in the bucket," not worth worrying about.
LARRICK: "I do believe that there should be lots of reasons to push people to the very high end of the scale, so there's no question about the need for greater efficiency. But if we're just simply thinking getting rid of cars and replacing them, the urgent place to do it is at that low end."
Rick Larrick of Duke University was interviewed by Science magazine for their podcast, and it you'd like to hear more, we'll have a link on our website, voanews.com/ourworld.
Around the world, professional athletes spend a lot of time on the road, traveling thousands of kilometers across several time zones for international competitions like the Olympics or football tournaments. Here in the U.S., baseball teams frequently fly to away games. But does all of this traveling affect the results? According to the latest research, the answer is yes. Eric Libby explains.
LIBBY: Every year, here in North America, Major League Baseball teams cram 162 games into a six-month season. During this time, teams criss-cross the country, through the nation's four time zones, to play games. As anyone who does a lot of long-distance commuting can tell you, that can make you tired. And Dr. W. Christopher Winter thought all that travel had to have an effect on the athletes' performance.
As medical director of the Martha Jefferson Hospital Sleep Center in Charlottesville, Virginia, Winter thinks a lot about the importance of getting a good night's sleep. So, he looked back at the past ten baseball seasons to see if teams that crossed more time-zones were more likely to lose. At the SLEEP 2008 conference in Baltimore this month, Winter presented his findings:
WINTER: "The results of the ten-year study do show that circadian advantage, or when a team plays more acclimated to their current time zone than their opponent, is a statistically significant factor in whether a teams wins or loses — probably smaller in magnitude than home-field advantage but clearly present."
LIBBY: In other words, when a team from an east coast city like New York travels to Seattle on the west coast, where it's three hours earlier, they are three hours off their schedule and at a disadvantage. An 8pm game in Seattle would feel like 11pm for the New York team, so instead of being at their peak physical performance their bodies think they should be getting ready for bed.
Since we can adjust our body clock by about an hour a day, it can take several days to make up the difference. Winter says the effect is more pronounced the more your body clock is off from the time-zone you're in ... so for that New York team, it will be hardest to win the first game.
WINTER: "So you would think well it is one game lost here and one game won there. Big deal. And I think that with athletic sports it IS a big deal to them. And every year when you look at baseball playoff time, there is always a team that misses the wild card [playoffs] by one game versus another."
TEXT: Although he looked at Major League Baseball, which funded the study, Winter's findings have implications for everyone who challenges their body clock ... like business travelers, factory workers, and emergency room doctors.
WINTER: "Any time your sleep or circadian rhythms is being disrupted, there is a consequence to pay: either in terms of your health — immune system — function, your performance in your job, your mood, your irritability. So these things are real effects."
LIBBY: W. Christopher Winter says people can help avoid large disruptions in their circadian rhythms with regular exercise, gradually adjusting their body clock before travel, and consistently getting a good night's sleep.
So the next time your team loses, besides blaming it on the referees or the color of the uniforms, you can now blame it on the time-zone. I'm an awake Eric Libby, in Washington.
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That's our show for this week. If you'd like to get in touch — maybe you have a science question for us — email us at firstname.lastname@example.org. Or use the postal address —
Voice of America
Washington, DC 20237 USA.
Faith Lapidus edited the show. Bob Doughty is the technical director. And this is Art Chimes, inviting you to join us online at voanews.com/ourworld or on your radio next Saturday and Sunday as we check out the latest in science and technology ... in Our World.
Our World — 21 June 2008