Science News

Thursday, June 01, 2006

Testosterone Pumps Up Hyrax Females

Testosterone Pumps Up Hyrax Females
By Jennifer Viegas, Discovery News

May 22, 2006— Testosterone may be known as the "male hormone," but researchers have discovered that female rock hyraxes have significantly higher levels of the chemical than their male counterparts.

It is the first time an adult female mammal has been found to possess testosterone levels consistently equal to, or higher than, those found in males of the same species.

Since female members of the furry, badger-like species often outrank males, the find suggests hormone levels may help determine who's the boss, and who is not.

"Testosterone probably contributes to females’ aggression and social rank, along with other androgens as well," said Lee Koren, lead author of the study, which was recently published in the journal Hormones and Behavior.

Koren, a researcher in the Zoology Department at Tel Aviv University, Israel, added, "High hormonal levels may also contribute to females’ lack of choosiness in the mating season. Finally, testosterone also acts as a stress hormone."

"It is possible that females -- with their roles as mothers, sisters and group leaders -- are, understandably, very stressed," she said.

The researchers observed six hyrax social groups in Ein Gedi, Israel. The groups consisted of adult females, adult males, pups and a group of male bachelors that slept in separate burrows.
Some older males ranked among the most dominant members -- below a female or two -- but younger males were among the lowest-ranked.

Hair and blood tests revealed females had as much or more testosterone than males.
To eliminate the possibility they were observing an isolated phenomenon, the researchers studied other hyraxes from zoos around Israel and another group in the northern part of the country. The analysis yielded similar results.

Males are the dominant sex in most mammal species, but among rock hyraxes, low-ranked bachelors can often be seen sitting alone or huddling with females. Although female hyraxes are no larger than males, they are more likely to fight.

Previous studies suggest testosterone promotes dominance and aggression in human males, with levels rising in men during a challenge. Winners' testosterone levels rise after a fight, while losers experience a testosterone decline.

Research led by James Dabbs, a professor of psychology at Georgia State University in Atlanta, further supports the apparent testosterone-dominance connection.

Dabbs and his team measured the hormone levels of female prison inmates. Women who had committed violent crimes and those who demonstrated "aggressive dominance" in prison had higher than normal testosterone levels.

Neither Dabbs nor Koren, however, are sure which comes first -- the violent behavior or the testosterone. Aggression, whether evolved at the species level or developed over an individual's lifetime, may precede the body’s release of the hormone.

"It’s like the chicken and the egg," concluded Koren, "but hormones come to serve behavior, I think, and not the opposite."


Study: Chimps and Early Humans Interbred

Study: Chimps and Early Humans Interbred

May 17, 2006 — Our early ancestors interbred with chimpanzees after the two species diverged millions of years ago, new research suggests.

The provocative idea is sketched by U.S. genome experts, who have discovered that hominids and chimps diverged far more recently -- and over a much longer timescale -- than previously thought.

During that period, the authors theorize, the two primate species were rather more than kissing cousins: They had sex, swapping genes before making a final split.

"The (...) analysis revealed big surprises, with major implications for human evolution," said Eric Lander, one of the paper's co-authors and founding director of the Broad Institute, a research collaboration between Harvard University, MIT and the Whitehead Institute.

Until now, the belief was that humans and chimpanzees shared a common ancestor but parted ways around 6.5-7.4 million years ago.

One basis for that idea is a carbon-dated fossil called Toumai, believed by many scientists to be the oldest known human. Others, however, dismiss Toumai as an ape.

The estimate is also backed by the molecular clock, a way of calculating evolution on the basis of the speed at which genes mutate.

Previous molecular clock studies have focussed on the average genetic difference between humans and chimps. But the new paper, published online by the British journal Nature, takes a different approach.

Exploiting the mountain of data from the human and chimpanzee genome projects, the researchers compared the genetic codes of the two species as they are today, estimating the ages of key sequences rather than the overall average age.

They believe the two species split no later than 6.3 million years ago and probably less than 5.4 million years ago, one to two million years earlier than the Toumai estimate.

Moreover, it appears that "speciation" of chimps and hominids -- the process by which they emerged as separate species -- took an extraordinarily long time, around four million years in all.

The youngest chromosome in the human genome is the X, which helps determine gender. On average,the X chromosome is about 1.2 million years more recent than the 22 non-sex chromosomes, the scientists found.

Lander describes the X chromosome's age as "an evolutionary 'smoking gun'."

Thus something unusual must have happened on the way to speciation: an initial split between humans and chimps, followed by interbreeding, and then a final separation.

"It is possible that the Toumai fossil is more recent than previously thought. But if the dating is correct, (it) would precede the human-chimp split," said lead author Nick Patterson, also at the Broad Institute.

"The fact that it has human-like features suggest that human-chimp speciation may have occurred over a long period with episodes of hybridization (inter-breeding) between the emerging species."

A gradual divergence of species through hybridization, rather than a quick break, may be far more common than scientists have suspected.

"That such evolutionary events have not been seen more often in animal species may simply be due to the fact that we have not been looking for them," said the team's senior author, David Reich.


'Hogwarts' Dragon Unveiled

'Hogwarts' Dragon Unveiled
By Larry O'Hanlon, Discovery News

May 23, 2006 — A dragon-like dinosaur named after Harry Potter's alma mater has performed a bit of black magic on its own family tree, say paleontologists who unveiled the "Dragon King of Hogwarts" on Monday in Albuquerque.

The newly described horny-headed dinosaur Dracorex hogwartsia lived about 66 million years ago in South Dakota, just a million years short of the extinction of all dinosaurs. But its flat, almost storybook-style dragon head has overturned everything paleontologists thought they knew about the dome-head dinos called pachycephalosaurs.

"What you knew about pachycephalosaurs -- you can chuck it," said Spencer Lucas, curator of paleontology at the New Mexico Museum of Natural History.

"Dracorex hogwartsia is a rather fantastic new dinosaur," affirmed paleontologist Robert Sullivan of the State Museum of Pennsylvania.

For years dinosaur experts had thought the classic dome-headed, head-butting sorts of pachycephalosaurs evolved from earlier flat-headed ancestors. The last thing they expected to find at the end of the Age of Dinosaurs was a dramatically flat-headed pachycerphalosaurs, or "pachy."

"If you were going to predict the kind of dinosaur that would live at that time, it would not be this," said Lucas.

Without so much as a nod of the head or the waving of a wand, hogwartsia has reversed the pachy family tree.

"Instead of going from flat-headed to domed, you're going from dome-headed to flat," Sullivan told Discovery News. Along with several colleagues, Sullivan co-authored the first detailed study of the new dinosaur, published this week in the New Mexico Museum of Natural History & Science Bulletin.

Dracorex hogwartsia, which translates as "Dragon King of Hogwarts," was unearthed in 2003 in the Hell Creek Formation of South Dakota by three amateur fossil hunters working in cooperation with the Children's Museum of Indianapolis. But it wasn't until it was at the museum, while the fossil was being carefully prepared, that renowned dinosaur researcher Robert Bakker happened to catch sight of it while visiting. Bakker then recruited pachycerphalosaurs expert Sullivan and other paleontologists to take a closer look.

As for how it got its name? A group of children at the Children's Museum of Indianapolis drew the connection to the fanciful school of witchcraft that the famous fictional wizard Harry Potter attends and came up with the name hogwartsia..

"It's a very dragon-like looking dinosaur," said Sullivan.

J.K. Rowling, author of the Harry Potter series, has been notified and apparently rather likes the new name.

"I am absolutely thrilled to think that Hogwarts has made a small claw mark upon the fascinating world of dinosaurs," said Rowling, according to a museum press release. "I happen to know more on the subject of paleontology than many might credit, because my eldest daughter was Utahraptor-obsessed and I am now living with a passionate Tyrannosaurus rex-lover, aged three.

"My credibility has soared within my science-loving family, and I am very much looking forward to reading Dr. Bakker and his colleague's paper describing 'my' dinosaur."


Fetus' Feet Show Fish, Reptile Vestiges

Fetus' Feet Show Fish, Reptile Vestiges
By Jennifer Viegas, Discovery News

May 18, 2006 — The feet of human embryos taking shape in the womb reveal links to prehistoric fish and reptiles, a new study finds.

Human feet may not look reptilian once babies emerge from the womb, but during development the appendages appear similar to prehistoric fish and reptiles. The finding supports the theory that mammalian feet evolved from ancient mammal-like reptiles that, in turn, evolved from fish.

It also suggests that evolution -- whether that of a species over time or the developmental course of a single organism -- follows distinct patterns.

In this case, the evolution of mammalian feet from fish fins to four-legged reptiles to four-limbed mammals to human feet appears to roughly mirror what happens to a maturing human embryo.

"Undoubtedly there are clear parallels between the mammal-like reptilian foot and the human foot," said Albert Isidro, an anthropologist at the Autonomous University of Barcelona, Spain and lead author of the study, which appeared in the journal The Foot.

Isidro and colleague Teresa Vazquez made the determination after analyzing fossils of a number of mammal-like reptiles that lived from 75 to 360 million years ago. The scientists also studied fossils of osteolepiform fish, which appear to be half fish and half reptilian. These fish lived 400 million years ago and had lungs, nostrils and four fins located where limbs would later be found in four-footed reptiles and mammals.

In 33-day-old human embryos, the scientists observed "the outline of a lower extremity in the form of a fin, similar to that seen in osteolepiform fishes." As the embryo continued to develop, the researchers focused their attention on two foot bones: the calcaneous, or heel bone, and the talus, which sits between the heel and the lower leg.

At 54 days of gestation, these two bones sit next to each other as they did within the reptile herbivore Bauria cynops, which lived around 260 million years ago. This ancient reptile had flat, crushing teeth and mammalian features.

At eight and a half weeks of gestation, the researchers found the two embryonic foot bones resemble those seen in the Diademodon vegetarian dinosaur, which lived around 230 million years ago.

"We can tell that the embryo is half way between the reptiles and the mammals (at this stage)," Isidro told Discovery News.

The two foot bones continue to develop until, at nine weeks, they resemble that of placental mammals as they emerged 80 million years ago.

This development of feet in the human embryo mirrors how the foot evolved over millions of years beginning with fish and ending with early mammals, according to the scientists.
Supporting the fish/foot link was the discovery last month of a new species, Tiktaalik roseae, which lived 375 million years ago. It had fish fins and scales, but also limb parts found in four-legged animals.

"Tiktaalik blurs the boundary between fish and land-living animals both in terms of its anatomy and its way of life," said Neil Shubin, professor and chairman of organismal biology at the University of Chicago and co-author of a related paper in the journal Nature.

H. Richard Lane, director of sedimentary geology and paleobiology at the National Science Foundation, said, "These exciting discoveries are providing fossil ‘Rosetta Stones’ for a deeper understanding of this evolutionary milestone: fish to land-roaming tetrapods (four limbed animals)."


Scientists Find a World of Neptunes

Scientists Find a World of Neptunes
By Irene Mona Klotz, Discovery News

May 18, 2006 — Scientists looking for planets around stars beyond our sun have found a system that contains an asteroid belt and three Neptune-sized worlds, one of which orbits in a zone where liquid surface water could exist.

Although the planet’s location could theoretically support life, researchers believe it is wrapped in an extensive hydrogen atmosphere and probably not suitable for life as we know it.
Nevertheless, the finding, which is reported in this week’s issue of Nature, is considered a key development in the continuing push to find Earth-like worlds elsewhere in the universe.

The trio of planets circle HD 69830, a pale sun-like star located about 41 light years away in the constellation Puppis. Astronomers using the infrared Spitzer Space Telescope previously discovered that HD 69830 probably has an asteroid belt in orbit. If true, the star would be the first similar in mass and age to the sun to have one.

The researchers also predicted that a planet’s gravitational tug was helping to keep the belt in order. With that hint and a sophisticated light-splitting spectrograph on the European Space Agency’s 3.6-meter telescope in La Silla, Chile, astronomers spent two years studying miniscule wobbles in the star’s orbit. They found three planets orbiting within the same distance that Earth orbits the sun.

Surprisingly, the hunt turned up no sign of a large Jupiter-class planet, making HD 69830 the first extrasolar planetary system without a massive planet.

"The planetary system around HD 69830 clearly represents a Rosetta stone in our understanding of how planets form," said Swiss astronomer Michel Mayor, a co-author of the paper. "No doubt it will help us better understand the huge diversity we have observed since the first extra-solar planet was found 11 years ago."

Although HD 69830’s planets are still 10 to 18 times bigger than Earth, the discovery is encouraging to researchers who are refining their planet-hunting techniques to find smaller, more Earth-like worlds.

"It implies that further low-mass planets will be spotted orbiting other stars," writes Harvard University astronomer David Charbonneau, in a related article in Nature.
Computer simulations indicate the innermost planet is probably rocky, like Earth. The middle one is a combination of rock and gas and the outer planet, which is the one predicted to lie in the zone of habitability, is estimated to have a rocky-ice core and a massive envelope of gas. Researchers believe the system is stable.


Human Cadaver Fungi Identified

Human Cadaver Fungi Identified
By Jennifer Viegas, Discovery News

May 22, 2006 — Deceased individuals supposedly "push up daisies," but a forthcoming study suggests human cadavers are more likely to support several species of white and yellow fungi.
The study is the first to describe in detail species of fungi obtained from human corpses. In the future, forensics experts may use the information during criminal investigations to determine an individual’s time of death.

Fungi -- which lack chlorophyll, leaves, and true roots and stems -- often form part of the natural decomposition process that recycles nutrients back into the food chain.
In this case, as lead author Kiyoshi Ishii told Discovery News, "The fungi feed on the dead."
Ishii and his colleagues analyzed two humans whose bodies were found decomposing in very different environments. The first was a corpse discovered lying face down on a concrete floor in an abandoned house. Police determined the body belonged to a 72-year-old man who had been missing for 10 months. The scientists observed yellow and white fungi on the deceased’s chest, abdomen and thighs, but little insect infestation, probably because the house was dry and isolated.

The second case study involved skeletal remains clad in a shirt and pants, which all were found in a forest next to a rope hanging from a tree branch. Forensics specialists determined the body belonged to a 50-60-year-old man who had hung himself at least 6 months before the body’s discovery. The scientists once again detected yellow and white fungi growing on the corpse.
Ishii, a biologist at Dokkyo University School of Medicine in Japan, and his team collected the fungi and incubated them in a laboratory. They identified several species including Gliocladium sp., a slimy counterpart to penicillin; Eurotium chevalieri, a fungus that can be bright yellow; and Eurotium repens, which is commonly found in soil. The Eurotium species dominated the collected samples.

Ishii explained that the white and yellow coloration is associated with the sexual stages for Eurotium fungi. The parasite produces threadlike filaments that terminate with circular, colorful structures called ascomata that are involved in reproduction. The fungi also produce colorful conidia, or asexual spores, which tend to form in the morning and germinate in the afternoon and evening hours.

Ishii said the environment in which a body lies, rather than the biochemistry of the individual or the manner of death, tends to dictate how much or how little fungi will colonize a cadaver. The team’s findings have been accepted for publication in the journal Legal Medicine.

Yuichi Chigusa, a medical parasitologist and entomologist at Dokkyo Medical University’s School of Medicine in Soka City, Japan, told Discovery News that fly larvae usually infest corpses within an hour to a half-day after the victims’ death, followed by Coleoptera (beetles) infestation and then fungal colonization. He is excited about the potential of fungi for further aiding detective work.

"I am surprised that fungus is a potential tool for determining post mortem intervals in cadavers without infestation of dipteran larvae and/or beetles," Chigusa said. "Therefore, I think it is very important that forensic pathologists, forensic entomologists and forensic mycologists cooperate in determining post mortem intervals during forensic analysis."


Pick Your Poison: Smog or Global Warming?

Pick Your Poison: Smog or Global Warming?
By Larry O'Hanlon, Discovery News

May 18, 2006 — A study of the strange climate changes in the Indian Ocean has uncovered a frightening climatic dilemma: By cleaning up smog, we could accelerate global warming.

Extensive air monitoring with unmanned aircrafts along with satellite and sea surface temperature data are showing that the brown clouds of polluted air from India have been absorbing sunlight before it reaches the northern Indian Ocean surface -- thereby "masking" global warming there and causing the waters to cool. When the cooling effect is strong enough, it repels the Indian Monsoon, causing deadly droughts in the world’s most populated region.

Meanwhile in the equatorial and southern Indian Ocean, beyond the reach of the brown clouds, global warming has continued to heat up waters and strengthen the engine that creates the monsoon. The result is a growing seasonal temperature difference between the southern and northern Indian Ocean and an unpredictable climate situation that tends to shift between extremes. A report on the phenomenon appears in the current issue of the Journal of Climate.

"It’s not just the Indian Ocean," said atmospheric scientist V. Ramanathan of the Scripps Institution of Oceanography at University of California, San Diego. "It’s happening globally."
The smokiest air is being pumped into the air mostly by less developed countries, where more people burn wood, dung and other soot-prone, low-temperature combustibles. The smoke particles -- called aerosols -- filter out five to 10 percent of the sunlight and halve the local surface effect of global warming, Ramanathan explained.

Aerosols survive only about a week or two in the air before they are rained out, but in that time they can travel far and have a powerful effect. Somewhere between 30 and 60 percent of global warming is thought to be masked by aerosols, said Ramanathan.

At the same time, industrialized nations have been pumping out more greenhouses gases into the atmosphere. These can survive for centuries and get evenly mixed throughout the atmosphere. The result is that the greenhouses have been steadily heating things up globally, while the aerosols have been cooling things regionally -- creating more potential for weather extremes.

Sun-blocking soot from Amazonia may play a similar regional role, along with smoke from central Africa that is often blown over the Atlantic, explains climate researcher William Collins of the National Center for Atmospheric Research in Boulder, Colorado. Even in the northern hemisphere, there is still plenty of smog to go around.

"People tend to not understand that smog has a global effect," Collins told Discovery News. "The US is polluting Europe and China is polluting the US," he said, referring to how winds rapidly carry pollutants east around the northern hemisphere. "We’re exchanging aerosols with each other."

The ironic upshot, of course, is that regional efforts to make air less toxic could unleash the full warming effects of all those greenhouse gases. About the only way out of the dilemma is to reduce greenhouse gas emissions, which is what many industrialized countries are trying to do.
"This whole drama is playing out on a miniature scale in the Indian Ocean," said Ramanathan.


Poverty Increases Teens' Risk of Overweight

Poverty Increases Teens' Risk of Overweight
By Serena GordonHealthDay Reporter on 05/23/2006

TUESDAY, May 23 (HealthDay News) -- Poor, older teenagers are more likely to be overweight than their well-off counterparts.

That's the conclusion of a new study that found the prevalence of overweight was more than 50 percent higher in older teens living below the poverty line, compared to those living above the poverty line. However, the study found no association between poverty and overweight in younger teens -- those between the ages of 12 and 14.

The study also looked for important factors that might contribute to teen overweight, and concluded that physical inactivity, increasing consumption of sweetened beverages and skipping breakfast were important forces, especially in poorer communities.

"Those who live in poverty are about 50 percent more likely to be overweight compared to those not living in poverty," said the study's lead author, Richard Miech, an associate professor in the department of mental health at Johns Hopkins University's Bloomberg School of Public Health.

"Not only that, but one of our key findings is that this difference has emerged recently. In the '70s and '80s, there was no difference at all," said Miech.

The study findings appear in the May 24/31 issue of the Journal of the American Medical Association.

The number of overweight American teens has risen dramatically over the past 30 years. And, the number of adolescents considered overweight has more than doubled in that time period, according to the study.

With the rise in the prevalence of overweight, health-care professionals are concerned that diseases such as type 2 diabetes, high blood pressure and sleep apnea will also dramatically increase and begin to affect younger and younger people.

To get a better idea of how many teens are overweight and what populations are most at risk, the researchers pooled data from four different nationally representative surveys -- the U.S National Health and Nutrition Examination Surveys (NHANES) from 1971-1974, 1976-1980, 1988-1994 and 1999-2004.

The four surveys included more than 10,000 children between the ages of 12 and 17. Information was gathered on height, weight, physical activity, dietary habits and socioeconomic status.

The researchers used U.S Census Bureau data to assess poverty level status. As an example, in 2004, a family of four with an income of less than $19,157 was considered to be living in poverty.

The researchers didn't find any significant difference in the prevalence of overweight in young teens (12-14) based on income levels. However, the difference was clear in older teens (15-17). The rate of overweight in older adolescents from poor families was 23 percent, compared to only 14 percent for older teens from more affluent areas.

Some factors that may influence that difference, according to the researchers, are sedentary lifestyles, skipping breakfast and drinking sweetened drinks, such as energy drinks, soda and fruit juices.

"In the past 10 years, the percent of calories that adolescents get from sweetened beverages has increased by 20 percent, and particularly among the poor," Miech said.

He said the recent voluntary withdrawal of soft drinks from schools is a step in the right direction, but added that schools and parents need to do more to encourage physical activity.
Cathy Nonas, a registered dietician and director of the diabetes and obesity programs at North General Hospital in New York City, agreed that physical activity is essential.

"Kids often end up with less gym time, to have more class time, so they can test better. We're trying so hard to get math and English scores up that we're destroying their health," said Nonas. "We're creating an environment for our children that is very unhealthy."

Plus, she added, in urban areas, the problem is compounded because there often isn't room for fields or gyms.

She recommends walking as much as possible, and added that the whole family should be walking. Additionally, she suggests that when teens are listening to music, they shouldn't just listen passively, but get up and dance.

Both Nonas and Miech said eating breakfast is important, and that numerous studies have shown that skipping breakfast can contribute to excess weight. Nonas said if you don't have time to sit down to a bowl of cereal and a piece of fruit, grab a high-fiber, high-protein nutrition bar that's low in sugar.


Caffeine Therapy Reduces Lung Problems in Preemies

Caffeine Therapy Reduces Lung Problems in Preemies
By Serena GordonHealthDay Reporter on 05/17/2006

WEDNESDAY, May 17 (HealthDay News) -- Caffeine therapy helps protect the lungs of premature infants from damage.

That's an early finding from an international, multi-center trial designed to assess the safety of caffeine therapy for the treatment of apnea of prematurity.

Apnea of prematurity is very common in preterm infants, because their lungs are underdeveloped and the central nervous system, which automatically directs the body to breathe, is immature and often not functioning properly. It's not known exactly how caffeine therapy helps these tiny babies breathe better, but its major benefits are believed to come from its stimulant effect on the respiratory system.

"In this study, we test a treatment that has been in use for a fair bit of time, although past studies have been very limited and very short-term. Our aim was to rigorously examine the long-term safety of this treatment and the long-term effects," said study lead author Dr. Barbara Schmidt, a professor of pediatrics, clinical epidemiology and biostatistics at McMaster University Medical Center, in Hamilton, Ontario, Canada.

Although the original objective of the study was to assess caffeine therapy's safety after two years, the researchers released their findings early, when it became clear that the treatment could reduce the rate of bronchopulmonary dysplasia (BPD) -- a common type of lung damage that occurs in premature infants.

"We found clear evidence of short-term benefit," said Schmidt.

The findings appear in the May 18 issue of the New England Journal of Medicine.
Schmidt's study included just over 2,000 premature infants -- the average gestational age was 27 weeks. The babies were born in Canada, Australia and England. They were randomly assigned to receive either caffeine therapy or a placebo during the first 10 days of life, until drug therapy for apnea was no longer needed.

For the report, the researchers assessed the babies just before discharge from the hospital. They considered BPD to be present if babies needed supplemental oxygen therapy.
Overall, 36 percent of the babies who received caffeine therapy needed supplemental oxygen, compared with 47 percent of the babies on a placebo. And babies receiving caffeine therapy needed an average of one week less of ventilator therapy than babies on a placebo, according to Schmidt.

Babies on caffeine therapy did gain slightly less weight, according to the study. But there were no differences in the rates of death and brain injury between the two groups.

"The short-term outcomes are really quite reassuring," said Schmidt. "I know from doing this study that quite a few parents are anxious, but for now, it looks OK."

Schmidt's team is continuing to follow these babies, and will report its findings on caffeine therapy's safety after two years. She said the researchers have also recently received a grant to follow the children through age 5.

Dr. Eduardo Bancalari, director of the division of newborn medicine at the University of Miami Miller School of Medicine, said, "For parents, this study is reassuring. Almost all of these babies are receiving caffeine therapy, and this study shows it's effective at getting them off mechanical ventilation sooner and improves the long-term pulmonary outcome."

"It looks like caffeine may be a relatively safe drug. There's no evidence yet that caffeine has a detrimental effect," he said, but cautioned that it's too early in the trial to conclude there are absolutely no negative neurological effects from caffeine therapy. Bancalari also wrote an accompanying editorial that appears in the same issue of the journal.

"We have to wait for the follow-up. That's the main reason this trial was started. We're always concerned about these very immature babies," Bancalari added.


Cancer Vaccine Shows Promise in Mice

Cancer Vaccine Shows Promise in Mice
By Steven ReinbergHealthDay Reporter on 05/23/2006

TUESDAY, May 23 (HealthDay News) -- A new type of vaccine, tested in mice, could be a longer lasting form of cancer treatment and may even lead the way toward preventing cancer, Swedish researchers report.

The DNA-based vaccine was shown to prevent cancer growth in mice. The vaccine works by mimicking the effects of angiostatin, a piece of a protein that suppresses tumor growth by preventing new blood vessels from forming in tumors. This is a treatment strategy known as antiangiogenesis.

"This is a whole different approach," said Dr. Len Lichtenfeld, deputy chief medical officer of the American Cancer Society. "It's a way of using the body's own defense mechanisms to fight cancer. The implications are significant."

The findings appear in this week's issue of the Proceedings of the National Academies of Science.
According study author Dr. Lars Holmgren, of the Cancer Center at the Karolinska Institute in Stockholm, "the problem with angiostatin has been that it has a low half-life when given to patients," meaning it stays active in the body for only a short time.

"Therefore, we decided to find the [cell] receptor for angiostatin, which we did," he said. The researchers named that receptor "angiomotin."

In their study, Holmgren's team developed a method using a DNA vaccine to block the receptor by inserting the gene for angiomotin. Once the gene was inside mouse cells, it became a free-floating copy of the target receptor, he explained.

This caused the mice to develop immune antibodies to angiomotin, extending the effects of tumor-suppressing angiostatin.

The result: Vaccinated mice showed reduced growth of breast cancer tumors.
"We may have solved the problem of the low half-life of angiostatin by using either DNA vaccination or therapeutical antibodies," Holmgren said. "This opens up a new way of inhibiting angiogenesis," he said.

This method could be used to target angiogenesis-driven diseases, Holmgren said. In addition to cancer, these include eye diseases such as macular degeneration and atherosclerosis.

It has also been suggested that this approach could be used to prevent the growth of smaller tumors, Holmgren said. "But with this type of DNA vaccination, it's too early to say," he said.
Lichtenfeld said the discovery could be a breakthrough in researcher for the treatment and prevention of cancer. But he also cautioned that real applications are a long way off.

"This is an exciting study," Lichtenfeld said. "[But] it's a long way from the laboratory to the bedside to prove that this works. But if it does, we are talking about something that could be a preventive strategy for cancer. Of course, it's decades away."


Scientists Create Artificial Penis

Scientists Create Artificial Penis
By E.J. MundellHealthDay Reporter on 05/23/2006

TUESDAY, May 23 (HealthDay News) -- Success with randy, replicating rabbits suggests that an "artificial penis" made from a patient's own penile cells might someday help men challenged by tough-to-treat impotence.

In the study, adult male rabbits with severely damaged penises received a graft of specially engineered penile tissue. The animals then re-grew full penises that functioned normally -- even to the point of successfully impregnating females.

"This is very exciting -- the researchers have been working on this for a long time in a variety of different organs. It's not yet clinically available, but if it works and proves safe and effective, it would be a tremendous advance," said Dr. Ira Sharlip, a spokesman for the American Urological Association and a clinical professor of urology at the University of California, San Francisco.
Sharlip was not involved in the study, which was led by Dr. Anthony Atala, director of the Institute for Regenerative Medicine at Wake Forest University in Winston-Salem, N.C. His team reported its findings Tuesday at the American Urological Association annual meeting, in Atlanta.

Drugs like Cialis, Levitra and Viagra have revolutionized the treatment of impotence for millions of men over the past decade. However, some forms of erectile dysfunction remain very difficult to treat.

A condition called "corporal fibrosis" -- where the tubes of penile "spongy tissue" that maintain erection are gradually replaced by inactive, fibrous scar tissue -- remains largely untreatable. The disorder occurs when the penis' sensitive spongy-tissue cells don't get the oxygen they need to survive, usually because of a chronic reduction in blood flow.

"It's relatively common in men with diabetes and various forms of vascular disease, or men who've previously had infections -- usually infections of a penile prosthesis," Sharlip said. "There are men who have such severe fibrosis that nothing can be done to restore their natural erection function, other than to implant a surgical prosthesis," he added.

However, advances in biotechnology have spurred research into replacing dead tissues with new, living tissues grown in a laboratory using the patient's own cells. According to Sharlip, Atala has long been a pioneer in this field, working not just with penile tissues but with tissues from other organs.

In their latest study, the Wake Forest researchers first used standard biopsy techniques to harvest smooth-muscle and blood-vessel cells from the penises of healthy adult male rabbits. In the lab, the researchers used these cells to "seed" a special nutrient-rich collagen matrix. Over time, the cells multiplied within this framework to grow into new penile tissue.

Next, the team surgically removed all of the natural spongy tissue from the penises of the donor rabbits. They then grafted in the engineered tissue.

Atala's group tracked the rabbits' penile growth and function over the next one, three and six months.

The researchers found that the new penises were similar in structure to natural rabbit penises. The "artificial penis" also achieved and maintained erectile pressures equal to those of normal rabbit penises.

Next came the real test, as the rabbits that had received the new penises were presented with sexually mature females.

Things proceeded just as nature intended, the researchers said.

"Mating activity in the animals with the engineered [penis] resumed by 1 month after implantation," they reported. "Presence of sperm was confirmed in the vaginal vault of the female partners, and all females conceived and delivered healthy pups."

Sharlip cautioned this is a preliminary study involving animals. But he said that "rabbit tissue is fairly similar to human tissue. If it can be done in rabbits, it probably can be done in humans."
Doctors who treated men with corporal fibrosis in this way would still face another hurdle, however: Treating the underlying cause of the fibrosis itself.

"There's the question of how you restore that needed blood supply," Sharlip said. "You may be able to restore the natural spongy tissue of these erection chambers, but in a patient with severe corporal fibrosis you also have to get the blood supply to come back into the new, restored tissue." Without that steady source of oxygen, any implant might meet the same fate as the tissue it had replaced, he said.

Still, the advance does mark one of the few breakthroughs against the disorder in years, Sharlip said. And he added that success in tissue engineering has implications "not only for the treatment of erectile dysfunction but in the world of medicine in general."

"If we could re-grow and replace worn-out tissue [in other body parts], that would have tremendous implications," Sharlip said.


Friday, May 19, 2006

Study: Neptune Nabbed Its Moon

Study: Neptune Nabbed Its Moon
By Irene Klotz, Discovery News

May 10, 2006— Back when the solar system was young, when planets and their growing brood of satellites were angling for clear orbital slots around the sun, Neptune might have nabbed its giant moon Triton from a pair of passing sister planets, a new study says.

Dual systems like Pluto and its large moon Charon are not uncommon among objects in the Kuiper Belt region, located beyond Neptune's orbit, astronomers say. About 10 percent of the known objects in this region have partners.

Craig Agnor, with the University of California at Santa Cruz, was sitting in a lecture about binary Kuiper Belt objects when he got the idea that Neptune may have kidnapped its main moon Triton from such a pair.

Triton stands out among all the large moons in the solar system because it orbits Neptune in a direction opposite to the planet's rotation, a so-called retrograde orbit.

While most scientists explained the moon's odd orbit and inclination by some variation of a capture scenario — a collision between objects, for example — Agnor had been long troubled by details that did not jive with any of the interpretations.

"It's been this old problem to work on," Agnor said in an interview with Discovery News. "The existing answers, there was something just a little unsettling about them."

When they used a binary system rather than a solitary object to generate a computer model of how the relationship started solved many of the theories' flaws, Agnor and University of Maryland astronomer Douglas Hamilton report in this week's issue of the journal Nature.

The most troubling conundrum was accounting for the tremendous amount of speed Triton must have shed to leave itself vulnerable to Neptune's gravitational embrace. The collision theory, for example, would have required an impact so powerful that Triton itself should have been destroyed.

Scientists also have suggested that Neptune once had an extended gaseous atmosphere, which could have gradually slowed Triton until it fell into orbit around Neptune.

But Neptune seemed to have evolved slowly and probably never had much more atmosphere than it has today, pointed out French astronomer Alessandro Morbidelli in a related Nature article.

Agnor and Hamilton show that if Neptune chanced upon a pair of mini-planets, similar to the Pluto-Charon system, the encounter could have ripped one from its partner.

Computer models prove that the object closer to Neptune, which in this case would have been Triton, would have lost enough velocity in the process to fall into orbit around its abductor.
The partner object likely would have been buffeted by Neptune's gravity, passed along to Uranus and then Saturn until it finally reached giant Jupiter and was booted out of the solar system altogether, Agnor said.

The researchers are now curious to see if other eccentric moons in the solar system have similar life stories.


Study: Goats Choose Fine Flavors

Study: Goats Choose Fine Flavors
By Jennifer Viegas, Discovery News

May 16, 2006 — Given a choice of flavors, goats and sheep prefer truffle, according to a new study of the animals' food faves.

The study, published in this month’s Small Ruminant Research journal, found that while sheep and goats have similar tastes, sheep have a more discriminating palate.

"Flavor does appear to be more important to sheep than to goats," said Iain Gordon, one of the study’s authors. "We didn’t test why this is the case, but it may be because goats generally have a more catholic diet than do sheep in the natural world, and so will eat a range of things with different flavors."

In order of preference, sheep enjoy truffle, garlic, onion, apple, caramel, maple and orange flavors, according to the new research. Goats prefer truffle, onion, apple and garlic.

Gordon, a professor and researcher at the CSIRO Davies Laboratory in Aitkenvale, Australia, and his colleagues recruited ten male Scottish Blackface sheep (species Ovis aries) and ten male feral hybrid goats (Capra hircus), as taste testers for the study.

The researchers treated nutritionally-enhanced food pellets with a range of synthetic, human-grade flavorings, avoiding the bitter flavors goats and sheep tend to dislike. After the animals fasted for an hour, the researchers presented basins containing the flavored feeds for 30 minutes.

By weighing each basin at the end of the taste test, the researchers determined how much food of each flavor the ruminants consumed. As for humans, a cleaner plate -- or in this case basin -- revealed some distinct preferences.

Both sheep and goats chowed down on the more pungent, earthy flavored feeds, shunning strawberries.

"My view regarding these flavors is that they are highly attractive, even though rare, because of health affects associated with consumption, for example anti-parasitic (action on) worms for garlic and onion," Gordon told Discovery News.

He also explained that truffles, onions and the actual other foods associated with the flavors were not given to the animals because the researchers only wanted to study the animals' preferences for flavors alone, independent of nutritional content.

Alan Duncan, a nutritional ecologist at The Macaulay Institute in Aberdeen, Scotland, told Discovery News that the flavor rankings "make sense."

"Both species tended to prefer flavors they might naturally encounter, such as the fungi-type truffle flavor and the onion and garlic flavors, which are found in the wild representatives of both cultivated vegetables," Gordon explained. "The fruity flavors tended to be avoided, and this is unsurprising since fruits do not generally feature in the repertoire of natural foods encountered by ruminant herbivores."

He added, "I was slightly surprised that sheep showed stronger preferences than goats. Sheep are predominantly a grazing animal, whereas goats readily consume shrubs and woody vegetation."

Now that these preferences are known, Gordon and Duncan suggested, the flavors might be added to feed to encourage livestock to eat, particularly when new foods are introduced.


Scientists Spot Secrets of SARS' Spread

Scientists Spot Secrets of SARS' Spread
on 05/16/2006

TUESDAY, May 16 (HealthDay News) -- U.S. researchers say they've identified key mechanisms that the SARS coronavirus uses to enter and infect cells.

The finding points to potential drug or vaccine targets to help fight SARS (severe acute respiratory syndrome), say a team from the Weill Medical College of Cornell University in New York City.

The virus uses a key coat protein, called S2, to gain entry into human host cells. The Weill team identified four important steps in this process.

The S2 protein on the outer membrane of the SARS virus is the "fusion machine" that allows the virus to fuse its outer membrane with that of the host cell, the researchers explained. After this fusion occurs, the virus can insert its genome into the host cell, where it replicates, erupts from the host cell, and spreads to new cells.

"So, understanding how S2 works is key to stopping infection," senior researcher Dr. Min Lu, associate professor of biochemistry, said in a prepared statement. "The molecule's heptad-repeat regions have unusual structural and thermodynamic features."

He and his team discovered and described the conformations of four distinct S2 "domains" -- structures and polymorphic interactions of the two heptad-repeat regions that are released and then refolded as the SARS virus fuses its membrane with that of the host cell.

"This process occurs in a series of steps the virus has devised over time to protect itself as it penetrates the cell," Lu said.

Each of these steps could provide a target for drugs or vaccines to fight SARS. The findings appear in the May 16 issue of the journal Structure.

A SARS outbreak first reported in Asia in early 2003 eventually spread to more than two dozen countries in Asia, Europe, North America, and South America and caused more than 8,098 cases of illness and 774 deaths before it was contained.


Adult Heart Pumps Help Kids Waiting for Transplant

Adult Heart Pumps Help Kids Waiting for Transplant
on 05/15/2006

MONDAY, May 15 (HealthDay News) -- U.S. researchers say that ventricular assist devices (VADs) -- mechanical pumps that maintain heart function in critically ill patients waiting for a heart transplant -- may be an option for children whose bodies are large enough to accommodate the devices, even though they're not designed specifically for kids.

"Over the last 10 years, these devices have been used in a limited number of children as a bridge to transplant," study author Dr. Elizabeth D. Blume, medical director of the heart failure/transplant program at Children's Hospital Boston, said in a prepared statement. "However, we know little about how useful these are in the pediatric population. In addition, there are limited options for smaller patients."

Blume and her colleagues reviewed the cases of 99 children in the United States who received a VAD between January 1993 and December 2003. The group included 67 boys and 32 girls, average age 13. Seventy-eight percent had a muscle heart disorder (cardiomyopathy) and 22 percent had congenital heart disease -- a heart defect that was present when they were born.
Of these patients, 78 survived to transplantation. Children with cardiomyopathy did much better using the devices than those with congenital heart disease.

Over the 10-year period in this review, 77 percent of children with VADs survived until they received a heart transplant. However, in the last three years (2000-2003), the survival rate to transplantation was 85 percent.

"Bridging over 85 percent of patients successfully is really encouraging. It shows that, despite the fact that none of these devices were designed specifically for children, a group of smaller patients can take advantage of the adult technology and do as well, if not better. It seems we are getting better at patient selection and placing these devices," Blume said.

"Another important finding is that the long-term outlook after transplant was similar in children on VAD compared to those who did not have the devices," she said.

The study appears in the May 16 issue of Circulation.


Sunday, May 07, 2006

Study: One Coral Beats the Heat

Study: One Coral Beats the Heat

By Larry O'Hanlon, Discovery News

May 1, 2006 — Some corals may beat global warming, say researchers who have found at least one species that can live on even after it has been turned white by overly warm waters.
To survive, most corals depend on algae that lives on them, called zooxanthellae, which die easily during spats of ocean warming. When the algae die, most coral take on a bleached appearance and then die as well.

But tests on one coral species, Montipora capitata, showed that the coral can make due without its algae by gobbling up more zooplankton from sea water. The discovery provides a glimmer of hope that the warming of oceans due to global warming might not cause the complete disappearance of all coral reefs worldwide.

"We've been trying to tackle why some coral recover from bleaching events," said Andrea Grottoli, a coral researcher at Ohio State University. The unusual ability to switch food sources seems to be one of the secrets.

To uncover the survival strategy, Grottoli and her colleagues first brought some Hawaiian corals ashore from Kaneohe Bay and put them in tanks where half were exposed to seawater at the same temperature as in the bay — 80° Fahrenheit — and the other half exposed to water just six degrees warmer.

Neither group was given any zooplankton in the water to feed on, so they were entirely dependent on their algae for survival.

After 30 days corals were returned to the reef and monitored to see how they recovered, particularly those that had bleached. Montipora capitata showed an unusual ability recover once zooplankton was available.

To make certain that Montipora capitata was actually making due by eating zooplankton, Grottoli and her colleagues repeated the experiment, but the followed up. When they returned the starved, bleached corals to the reef, they let them eat for a day and then dissected hundreds of separate tiny individual coral animals and counted the individual zooplankton animals they had eaten.

"We had to prove that's what it was doing," she said of the labor-intensive work.
The results are summed up in an article by Grottoli, Lisa Rodrigues and James Palardy published in the April 27 issue of Nature.

Other researchers who study coral bleaching are hailing the discovery as a wake-up call — that they have been focusing too much on the symbiotic coral algae and not paying enough attention to what else coral animals are doing.

"I think the real point here us that a lot of community has been centered on the algae," said coral researcher Michael Lesser of the University of New Hampshire. "This particular paper adds a whole other twist. Now the question is how general is this?"

Grottoli said there was preliminary evidence of another coral in the Red Sea with similar dietary flexibility, but a lot more work needed to be done on corals worldwide to really hash out the details of how specific corals respond to warming oceans.

She also cautioned that regardless of how a few coral species might survive bleaching events, corals reefs worldwide are still facing a gigantic crisis.

"No matter what, coral species are going to decline," said Grottoli. "The projections are dismal: 60 percent loss in the next ten years."

Reefs are disappearing much faster than rainforests, she said, but because they are underwater and mostly out of sight, people are not aware of the loss.

That said, Grottoli's work provides tantalizing hints and raises many questions about what will happen to complex reef ecosystems as some species die and others move to different food sources.

"This could have profound impacts on how we look at corals after bleaching," said Lesser.


Did Monks Try to Make Gold?

Did Monks Try to Make Gold?

By Rossella Lorenzi, Discovery News

May 5, 2006 — A ceramic cone unearthed at a remote British abbey might indicate that Cistercian monks implemented the Benedectine motto "ora et labora" (pray and work) with another rule: "make gold."

On display for the first time at Bylands Abbey, which was founded in 1137 by Cistercian monks in North Yorkshire, the cone is what's known as an alembic.

The delicate apparatus, 8 inches tall and 6 inches across the base, originally sat on top of a "cucurbit" — a heated gourd-shaped pottery vessel that held a boiling concoction. Vapors given off by the boiling mixture would have passed though a small hole at the cone's apex into a pipe connected to a condenser.

The alembic could have been used in medicinal preparations, to distill alcoholic spirits by monks who fancied an illicit tipple, or in pursuit of the alchemist's dream — gold.

"Since no chemical traces have been found on the surface, we have no way of being certain of its use. However, we know that certain Cistercians, as with other monks, did experiment in alchemy," Kevin Booth, English Heritage's senior curator in the North, told Discovery News.
Born in ancient Egypt, where it flourished in the Hellenistic period, alchemy is considered the forerunner of chemistry.

Following the Aristotelian theory of elements, which stated that all things consisted of fire, air, water and earth, the early alchemists believed that gold could be obtained by altering the elements in a base metal.

A little shift in one metal's composition would have made a metal of low esteem, such as lead, turn into tin, iron, copper, mercury and finally, gold. Alchemists would have also tried to stimulate transmutation with a specific agent — the legendary philosopher's stone.
The Cistercians, known as the White Monks to distinguish themselves from the largest black-robed Benedictine congregation, banned alchemy in 1317. Despite the ban, rumors had it that the monks at Bylands Abbey had long tried to create gold.

Indeed, the alembic would support the account of 15th-century scholar Richard Dove of Buckfast, who described how one monk, Richard Archebold, saddled the Order with great debts in an attempt to "pursue the unattainable."

In 1470, Archebold wrote the abbot claiming he had managed to convert an amalgam of metals into gold, and asked for a loan in order to continue his experiments. By 1479, Archebold and the Bylands monks had accumulated substantial debts.

"This is an interesting story, but we should not run out the more likely uses, such as distilling alcoholic spirits. If the alembic had been found in association with mercury, then I would suspect alchemy. There was an example of this from a monastic site in Stamford, Lincolnshire, which contained other evidence of alchemy," archaeologist Glyn Coppack, author of The White Monks: Cistercians in Britain, told Discovery News.

Indeed, the Stamford vessel was found near a urinal: Urine, with quicksilver, was considered an essential ingredient of the alchemist's art.

"The line between religion and science was very blurred in those days. These findings do not directly support the claim of monks trying to make gold, but they certainly add to that possibility, Booth said.


Study Probes Bee Legs in Flight

Study Probes Bee Legs in Flight

By Jennifer Viegas, Discovery News

April 26, 2006 — Many flying bees dangle their legs as though they forgot to pull up their landing gear, but a new study has found that by extending their hind legs, bees can kick into maximum flying speed, which helps the buzzing insects to flee from predators, zip around in wind storms and more.

The study, presented earlier this month at the Society for Experimental Biology's annual meeting in England, also determined how bees maintain stability midair and what limits their maximum flight speed.

Stacey Combes, who led the research, focused her work on brightly colored, tropical orchid bees. Males will do almost anything for aromatic oils like cinnamon or eucalyptus, which they store in their enlarged hind legs, possibly to attract females.

Combes put an aromatic scent source in the mouth of a wind tunnel set up in a Panama forest. As orchid bees flew in for the scent, Combes adjusted the tunnel's wind speeds and analyzed how the insects flew.

"The unexpected thing I found was that as the bees fly faster and faster, they actually start to lower their huge hind legs below their body, instead of tucking them in to reduce drag like you would expect," she said. "It looks like the reason they're doing this is to create a nose-down pitching torque to help tilt their bodies forward to allow them to fly faster."
The technique is similar to how some old helicopters must tilt forward to offset wind drag before flying forward.

Combes, who is a research fellow in the Department of Integrative Biology at the University of California, Berkeley, also explained that when bees extend their legs, the limbs generate stabilizing forces, similar to how the extended arms of a spinning figure skater can improve stability.

Bees may reach a maximum flight speed of 23.8 feet per second, but at that speed, the insects can lose stability to the point where they may roll, fly upside down and even crash to the ground. At lower speeds, the legs can help to prevent such rolling and side-to-side movements.
Airplane Inspiration?Combes said bee flying might inspire new miniature aircraft designs that incorporate a device that functions like bee legs, which are structured somewhat like airplane wings.

"The legs are slightly convex on the outer surface and concave on the inner surface, and have a row of hairs on the trailing edge (back)," Combes said.

"This is similar to the general design of an airfoil (airplane wing), where a convex upper surface and concave lower surface, as well as tapered trailing edge, helps the airfoil generate lift forces by causing air to flow more quickly over the top than the bottom."

Combes said that below a certain size, fixed wing or helicopter-type flying machines do not work, so engineers have to build a craft with flapping wings. The U.S. military and other groups hope to use such mini flying robots for search and rescue missions and other applications. Bees could inspire future designs.

"It may be helpful to be able to reduce the number of control components needed by using one structure, like the orchid bee legs, to control both pitch and roll," she explained.
Graham Taylor, a member of Oxford University's Animal Behavior Research Group, said he was surprised that stability limited the upper, rather than the lower, speed at which orchid bees can fly.

He explained that helicopters often experience problems when they attempt to hover slowly, but bees indicate fast flying creates more defined limitations.
While Taylor thinks it is possible that bees could inspire new miniature aircraft designs, he suggested to Discovery News that birds might make a better model.

He said, "The problem is that evolution works with whatever it has to hand, so while it makes sense for an orchid bee to evolve to use its legs for flight control, a large moveable tail surface — which insects have never evolved, but birds have — would probably be more effective for flight control."


Americans Less Healthy Than the British

Americans Less Healthy Than the British

By E.J. MundellHealthDay Reporter on 05/02/2006

TUESDAY, May 2 (HealthDay News) -- Americans may have won the Revolutionary War, but 230 years later they're losing the battle for good health to the British.
An extensive new study comparing the health of middle-aged, white residents of both countries finds that "we get sicker, sooner," according to American co-researcher James Smith, a senior economist at Rand Corp.

The gap between the two countries is significant, despite the fact that people in the United States have a standard of living that is 25 percent higher than their counterparts across the Atlantic, and that they spend more than double on health care than the British -- $5,274 per capita vs. $2,164, respectively.

The health gap between the two nations "persists even after you take out things such as the large role of African-Americans with very poor health in the United States, or that people may be reporting health differences differently in the two countries," Smith said. "We also looked at biological markers of disease -- you take away the fact that there may be risk-factor differences in obesity, smoking and drinking."

Even with those factors taken into account, "you are basically back where you started," Smith said. "You find enormous differences in health between the two countries among non-Hispanic whites."

How big a difference? Using well-respected national survey data on the health and lifestyles of more than 6,400 Americans and 9,300 English people aged 40 to 70, the researchers found that U.S. citizens aged 55 to 64 are twice as likely as their peers in England to be diabetic (12.5 percent of Americans surveyed vs. 6.1 percent of British); 10 percentage points more likely to have high blood pressure (42.4 percent vs. 33.8 percent); 6 percentage points more likely to suffer from heart disease (15.1 percent vs. 9.6 percent); and at nearly double the risk for cancer (9.5 percent vs. 5.5 percent). Americans also had higher rates for heart attack, stroke and lung disease when compared to the British.

The findings appear in the May 3 issue of the Journal of the American Medical Association.
Smith said his team assumed that one possible explanation for the disparity might lie in differences in access to care: The United States relies on a patchwork system of private and public health care, whereas England offers universal, socialized medicine to its citizens. To account for the difference, the researchers factored out health-care access by limiting their analysis to financially well-off, non-Hispanic whites -- the vast majority of whom have access to care in both countries. The result: The gap persisted.

At this point, Smith said, he and his British colleagues who helped conduct the study are left scratching their heads.

"We have some plausible hypotheses for the difference in health outcomes," Smith said. A leading theory is that "it may matter how long you've been in an epidemic, and the big epidemic that separates the two countries right now is the obesity epidemic," he said. "We started first, and the English are catching up with us. It may really matter that we have had [rising obesity rates] 20 years longer than they have."

According to a Rand statement, the overall incidence of obesity in the United Kingdom rose steadily from 7 percent of the population in 1980 to 23 percent in 2003. However, in 1980, 16 percent of Americans were already obese, and that number climbed to 31 percent by 2003.
Furthermore, despite spending billions more on health care than the British, Americans "are not treating obesity," said Lona Sandon, an assistant professor of clinical nutrition at the University of Texas Southwestern Medical Center in Dalla. "We're treating the symptoms -- the heart disease, the diabetes, the hypertension, everything else. We're not addressing the underlying problem."

Sandon also noted that the English and their European counterparts are much less reliant on cars for transport than people in the United States. "When you go to England, Europe, you'll still see many people walking or using bicycles," she said. "In the United States, we've moved away from that and lessened our physical activity to a bare minimum."

Then there's the ever-expanding American dinner plate. According to Sandon, "our portion sizes are triple or four times what they should be, or what they were 20 to 30 years ago."
Smith stressed, however, that obesity may not be the only reason explaining the health gap. "It may also trace back to childhood health differences between the two countries," he said. And because stress is known to negatively affect health, it's possible that "we may live in a more stressful country than the English do."

Smith noted that the English don't live any longer than Americans do -- they just develop chronic or acute illnesses much later. The real challenge is to prevent or postpone these conditions in the first place, he said.

"The mortality rates among people around age 60 is about the same in both countries," Smith said. This means the U.S. health-care system may do a better job of keeping individuals alive after they develop diabetes, health disease or other illnesses. "But we don't do a better job at preventing people from getting sick in the first place."

However, with obesity rates rising in England, the British may not have much cause to be complacent. "We've had a few more years to get obese and develop chronic illnesses, whereas they are just beginning," Sandon said. "So, if they can look at these comparisons and say, 'We need to stop this now,' they might be better off in the long run."

The study has a different message for policymakers back in the former colonies.
"We have a 25 percent higher standard of living here in the U.S. than the English do," Smith said, "so achieving the level of health of the English should not be outside our reach."

Blood Clots From Heart Associated With Dementia

Blood Clots From Heart Associated With Dementia

By Ed EdelsonHealthDay Reporter on 04/28/2006

FRIDAY, April 28 (HealthDay News) -- Tiny blood clots that originate in the heart and wander to the brain could cause Alzheimer's disease and other forms of dementia, a British study indicates.

The researchers found these clots, formally called cerebral emboli, in the brains of 40 percent of 85 people with Alzheimer's disease and 37 percent of people with vascular dementia, according to their report in the April 28 issue of the British Medical Journal. Physicians from the University of Manchester found the same clots in only 14 percent to 15 percent of normal adults tested in the study.

The cerebral emboli "may represent a potentially reversible or treatable cause of dementia," the researchers wrote.

Cerebral emboli are a known cause of stroke. They often form in the circulatory systems of people with atrial fibrillation, an abnormal heart rhythm that enhances clot formation by causing blood to pool. They have not previously been associated with dementia.

"This is another indication that Alzheimer's disease probably is not just one disease," said Dr. Julie A. Schneider, an associate professor of neurology and neuropathology at the Rush Alzheimer's Disease Center in Chicago. "There are probably multiple things happening in the brains of older people, and some of them are vascular."

The finding fits in with the work done at the Chicago center on brain function and blood flow in older people, Schneider said. Cerebral emboli could interact with other dementia risk factors, lowering the threshold at which Alzheimer's disease or a related condition occurs, she said.
The British report "certainly needs follow-up," in part because it leaves some questions unanswered, Schneider said.

The answer to those questions might be available soon, said study author Dr. Charles McCollum, a professor of surgery at the University of Manchester.

"Were in the process of completing a two-year follow-up," McCollum said. "We dont know the results yet, but we should be publishing them shortly. After that, we can think about inhibiting the emboli with medication."

The major question that Dr. George Bartzokis, a professor of neurology at the University of California, Los Angeles, would like to have answered is the effect over time of the presence of cerebral emboli in older people.

The study measured cerebral emboli at one point in time, Bartzokis said. "For the patients, the issue would be are those with cerebral emboli doing worse over time than those without them?" he said. "For the normals, the question is whether those with cerebral emboli will get Alzheimer's disease."

Bartzokis had other questions about the study. He said the high incidence of cerebral emboli found not only in people with dementia but also in normal participants was "surprising." And the study excluded people taking anti-clotting medications such as aspirin, Bartzokis noted. Perhaps having older people take aspirin might reduce the risk of dementia, he said.

The results "clearly are something that should be looked into further," Bartzokis said. "But implying that emboli might be universal in dementia -- that is taking a huge leap."


Heart Attacks Are Biggest Threat to U.S. Firefighters

Heart Attacks Are Biggest Threat to U.S. Firefighters

By Amanda GardnerHealthDay Reporter on 04/27/2006

THURSDAY, April 27 (HealthDay News) -- Fires don't kill American firefighters as much as heart attacks do.

A new government study has found that sudden cardiac death is the leading cause of death in the line of duty for both volunteer and career firefighters.

Traumatic injuries from motor vehicle crashes while responding to an emergency were a close second for volunteers, said the report, which appears in the April 28 Morbidity and Mortality Weekly Report, a publication of the U.S. Centers for Disease Control and Prevention.
The real message, though, is that these causes are preventable and that things can be done to reduce the risk.

"The leading cause of death is sudden cardiac death, and we can reduce these risks by having fitness programs and annual physicals," said Marilyn Ridenour, co-author of the report and an epidemic intelligence officer with the CDC's National Institute for Occupational Safety and Health. "Fire departments should consider mandatory annual fitness exams for firefighters, and seat-belt use and safe-driving practices. That should help reduce these risks," she said.

"We do have standards, but we need implementation and adherence to the standards," said Rita Fahy, manager of fire databases and systems at the National Fire Protection Association in Quincy, Mass. "A lot of it comes down to behaviors."

According to Ridenour, the findings are consistent with previous data.

Fahy agreed. "The results are fairly consistent from year to year," she said. "Heart attack or sudden cardiac death is the major cause of firefighter death. Crashes would come in second. Speed and failure to wear seat belts are the most frequently cited contributing factors."

An earlier study had reported that, for the past 25 years, heart attacks have typically caused the most deaths among firefighters. However, as awareness of heart disease and prevention has increased, the number of deaths attributed to heart attacks has dropped by more than one-third, the report found.

There are 800,000 volunteer firefighters in the United States and 300,000 career firefighters. Volunteers tend to serve smaller communities (fewer than 25,000 residents), while career firefighters serve larger communities.

For the new study, Ridenour and her colleagues analyzed data from the U.S. Fire Administration, which keeps a database of all on-duty firefighter deaths based on death certificates and fire department interviews. On-duty firefighter deaths include all those that occur within 24 hours after a response to a call.

From 1994 to 2004, 610 volunteer and 368 career firefighters died while on duty, 97 percent of them male. The median age was 47 years for volunteers and 44 years for career firefighters.
Half of the deaths among volunteer firefighters were from heart attacks and 26 percent from motor vehicle-related trauma. Almost three-quarters (73 percent) of motor vehicle-related deaths were caused by crashes, 30 percent of which involved private vehicles. Eighty percent of the crashes occurred en route to calls, while 5 percent occurred during returns.

Among career firefighters, 39 percent of deaths were caused by heart attacks; 29 percent from other causes, such as burns, cerebral vascular accident or drowning; and 20 percent by asphyxiation (mostly from being caught or trapped).

In both categories of firefighters, most heart attacks occurred among people aged 45 to 54. The majority were attributed to stress and overexertion for both volunteers (98 percent) and professionals (97 percent).

The study also provided details of two particular fatalities, one of a volunteer and one of a career firefighter.

On July 28, 2003, two volunteer firefighters responding to a trailer fire sped down a two-lane road at about 80 miles per hour in a privately owned vehicle with emergency lights on. The speed limit was 55. The driver lost control when the vehicle drifted off the pavement. He was killed, and the passenger sustained serious injuries. The fire department required that firefighters obey local traffic laws.

In the second case, a 51-year-old career captain collapsed while responding to a fire in the attic of a two-story dwelling. An autopsy revealed that the man had cardiovascular disease. He had also suffered a heart attack 13 years prior and had undergone angioplasty of his right coronary artery. According to the article, under these circumstances, the captain should have been issued work restrictions.

And there are initiatives under way. The International Association of Fire Fighters (IAFF) has just started a new program to reduce vehicle crashes.

"A lot of that is education and changing the culture of firefighters," said Patrick Morrison, IAFF's health and safety director.

As for heart attacks, Morrison said, "Some of them are preventable; for some, we don't have the proper early screening and detection." Many cardiac stress tests, for example, only pick up when the person already has a 75 percent blockage, he said.

"We need to know if there are tests that will work earlier," Morrison said.


Key Factors Spur Older Cancer Patients to Quit Chemo

Key Factors Spur Older Cancer Patients to Quit Chemo
on 05/03/2006

WEDNESDAY, May 3 (HealthDay News) -- Physical weakness, treatment complications, and a lack of social and psychological support can keep elderly patients with stage III colon cancer from finishing chemotherapy after surgery, a new U.S. study finds.

Researchers at the University of Washington in Seattle analyzed data from nearly 3,200 stage III colon cancer patients who opted for chemotherapy after they'd had surgery for their cancer. Of those, 2,497 (78.2 percent) completed the chemotherapy treatment, which studies show can reduce the risk of death.

Among the patients who did not complete their chemotherapy treatment, physical frailty, treatment complications, and a lack of social/psychological support were cited as factors. The patients' doctors' characteristics did not play a role in failure to complete treatment, the study said. Black patients were as just likely as whites to finish chemotherapy.

"From these findings, interventions to improve social and physical support throughout the treatment course could be implemented, to test whether such support improves rates of chemotherapy completion in elderly colon cancer patients," the study authors wrote.
The findings appear in the May 3 issue of the Journal of the National Cancer Institute.


Saturday, May 06, 2006

"Amplification" Strategy May be Key to Combating West Nile Virus

"Amplification" Strategy May be Key to Combating West Nile Virus

CORVALLIS, Ore. – The spread of West Nile Virus appears to be triggered by a complex interaction of mosquitoes, nesting birds and specific weather patterns, scientists say, which leads to "amplification" of the virus within mosquito populations.

Researchers from Oregon State University and the University of Florida have identified how those factors mesh to create heightened risk of the West Nile Virus in southern Florida, and they hope to expand their studies to the rest of the nation.

Results of the research have been published by the Centers for Disease Control.
Many early hydrologic models predicting the transmission of West Nile Virus and other mosquito-borne diseases may have been a bit too simplistic, relying on factors such as total rainfall to estimate disease risk, said Jeffrey Shaman, an assistant professor of atmospheric sciences at Oregon State University. The situation, he adds, is much more complex.

"In some cases, rain can actually help control mosquitoes by flushing away larval habitats," Shaman said. "And simply having more mosquitoes doesn't necessarily mean that we'll experience a greater incidence of West Nile Virus. The mosquitoes themselves must first be infected with the virus. Researchers call the process through which more mosquitoes become infected 'amplification,' and there are a number of factors that lead to that stage.

"By identifying these factors in the wild, it will enhance our ability to create control strategies."
In their studies, Shaman and colleague Jonathan F. Day from the University of Florida found that spring drought followed by continual summer rainfall is critical for the amplification and transmission of West Nile Virus and a similar disease, St. Louis Encephalitis Virus, in southern Florida. When drought occurs early in the year, the limited water resources confine mosquito populations to selected habitats – specifically isolated, densely vegetated hammocks where conditions remain humid.

These moist hammocks also happen to be the spring nesting and roosting sites of many species of wild birds, which act as hosts and carriers for the diseases. While confined in the hammocks, the mosquitoes feed almost exclusively on the nesting birds and as a result, each bird is bitten by numerous mosquitoes. A single infected bird can thus infect many more mosquitoes than if conditions were wet and the mosquitoes were more broadly dispersed, Shaman said.

"This phenomenon, called 'drought-induced amplification,' is a key to transmission," he said.
When summer rainfall increases, surface humidity levels rise and the mosquitoes are able to disperse and initiate secondary transmission away from the original amplification sites, the researchers pointed out. With this dispersal, the mosquitoes are more likely to come into contact with humans – elevating the risk of human incidence of the diseases.

"Drought-induced amplification may be somewhat unique to southern Florida, where drought tends to occur in the spring and coincides with the birds' nesting season," Shaman said. "The mosquito situation itself also is somewhat unusual. In most areas of the country, one species of mosquito infects the birds and another species then passes the disease along to humans.
"Florida has one species of mosquito that routinely bites both," he added.

Not all of the world's more than 3,600 species of mosquitoes transmit diseases to humans. The mosquito must be sufficiently competent to act as a carrier, thus some species can act as hosts for certain diseases, while others are more "refractive," – not carrying enough of the disease to transmit it.

West Nile Virus transmission requires mosquito species that prefer feeding on birds, but like mosquitoes, not all birds are good carriers. Some are ineffective hosts, Shaman said, while others – like crows – are very susceptible and may die from the virus. Birds that are effective hosts may carry the virus and infect biting mosquitoes for 4-5 days before recovering from the illness.

"It is this coming together of factors that leads to the spread of the disease," Shaman said. "But because the amplification is concentrated – in time and space – it does make it easier to devise control strategies. Chemical application is the most likely scenario, but because it could be applied in selected areas, it would be more cost-effective and potentially less environmentally threatening."

The spread of West Nile Virus through the U.S. has been sporadic, the researchers say, with hotspots arising one year in Colorado, and other regions during other years. The key to understanding the spread of the disease is to investigate the local conditions that may lead to amplification.

"It is a localized phenomenon," Shaman said. "We have to understand what goes on at the local level, at the appropriate scale, before we can reach the same conclusions that we found in southern Florida. But in almost all cases, the amplification of West Nile Virus will start with mosquitoes that carry the disease mingling with birds that are good carriers.

"How fast and far it spreads from there depends on weather, terrain, vegetation, humidity, the types of birds that live in the region and even the number of housing developments in a given area," he added. "These are the variables that need to be studied across the country."

Shaman and Day hope to expand their studies to analyze different regions of the country and create models similar to that of southern Florida, where certain weather patterns set off the chain of events that leads to amplification.


HealthWrap: Autism gene found?

HealthWrap: Autism gene found?


OXFORD, England, May 4 (UPI) -- By deleting a gene from the brain of mice, researchers at the University of Texas Southwestern Medical Center have created mice whose behavior is reminiscent of autistic humans.

In an article published in Neuron Thursday, Dr. Luis F. Parada, director of the Center for Developmental Biology, and his colleagues show that the Pten gene may cause certain forms of autism.

While many autism sufferers have mutations in Pten, and it has long been thought to be linked with autism, this study is the first to show such a direct link between autistic-spectrum behaviors and Pten mutations.

The Pten gene was deleted from the hippocampus and the front of the brain for the purposes of the study, and then the mutant mice were left to mix with normal mice from the same litter.
The mice were then exposed to an inanimate object and to unfamiliar mice. The mutant mice were equally interested in the inanimate object and the other mice, while the normal mice were substantially more interested in the other mice, echoing the behaviors of autistic and non-autistic children.

"It would be really exciting if it turned out that we've zeroed in on the anatomical regions where things go wrong in autistic patients, regardless of how the autism occurs," Parada was quoted by IBNLive as saying.

-- Older Americans are less healthy than their British counterparts, a new study has found, despite U.S. per capita spending on health being double that found over the Atlantic.
Researchers from University College, London, in a study published in the Journal of the American Medical Association this week, analyzed British and American health surveys conducted on people age 55 and 64 to determine patterns in health, relative health on both sides of the Atlantic and the effects of social and economic status on health.
The scientists wrote, "Middle-aged to older U.S. residents have higher rates of diabetes, hypertension, heart disease, heart attack, stroke, lung disease and cancer than their English counterparts."

These differences existed despite no substantial disparity in the quality of care or rates of smoking, obesity, alcohol abuse, or other factors known to be detrimental to health.
American per capita medical spending is $5,274 a year, compared with $2,164 a year in Britain, the article states.

"Whether greater financial expenditures translate into better health for a country's citizens is uncertain," JAMA said in a press release, but "differences in socioeconomic groups between the two countries were so great that those in the top education and income level in the U.S. had similar rates of diabetes and heart disease as those in the bottom education and income level in England."

-- A California hospital may have inadvertently exposed 300 morbidly obese patients to HIV and hepatitis after it was found that equipment was not being sufficiently sterilized.
Scripps Memorial Hospital in San Diego Wednesday revealed that some equipment used in stomach-reduction operations had not been properly cleaned and asked those patients who may have been infected to take blood tests.

"The risk (of infectious disease) is extremely low but to be safe and take every precaution we are having blood drawn and tested, looking for HIV, Hepatitis B and Hepatitis C," hospital spokesman Don Stanziano told reporters.

The equipment in question is a gastroscope, a specialized piece of equipment for use in stomach-reduction operations. It emerged that a nurse at the hospital had not properly sterilized the gastroscope, which cannot be exposed to high temperatures.

State health officials are investigating the nurse's failure to use the proper procedure, while results from the blood tests will take two to three weeks to come through.

-- Researchers at Harvard Medical School have established that some people are predisposed to post-traumatic stress disorder.

In the study, scientists submitted 25 combat veterans with post-traumatic stress disorder, their non-combat identical twins and 24 combat veterans without post-traumatic stress disorder and their non-combat identical twins to a series of neurological tests, called the Neurological Soft Signs scale, which tests for difficulties in learning, coordination and behavior.

Those with post-traumatic stress disorder scored higher on the NSS scale than those without. And so did their twins, suggesting that the disorder might not be acquired as a result of exposure to a traumatic or stressful situation but rather "represent an antecedent familial vulnerability factor for developing chronic post-traumatic stress disorder on exposure to a traumatic event," write the authors in the May issue of Archives of General Psychiatry.

-- A study presented this week at a child health meeting found that spray-administered influenza vaccinations were 55-percent more effective than flu shots when given to children under five.

Dr. Robert Belshe, of St. Louis University, who led the study, was quoted by as saying: "Our current thinking is that to control influenza, we really have to vaccinate all children. Anything that makes it easier and more effective (to vaccinate) children is going to contribute a lot to the protection against influenza."

FluMist, which is the only spray flu vaccine made of live -- weakened -- influenza virus on the U.S. market, is not currently sold for use in children under 5.

Copyright 2006 by United Press International. All Rights Reserved.


Oven-roasted vegetables may hurt teeth

Oven-roasted vegetables may hurt teeth

DUNDEE, Scotland, May 4 (UPI) -- A British study finds that oven-roasted vegetables, while tasty and healthy, may be destructive to teeth.

Researchers at the University of Dundee prepared ratatouille, the Provencal vegetable stew, by two different methods -- roasting vegetables in the oven for 45 minutes, and cooking them in the traditional way, in a stewpot on top of the stove.

"The acidity of ratatouille prepared by oven roasting is the same as that of some carbonated drinks that, when consumed in excess, are believed to contribute to the development of dental erosion," Dr. Graham Chadwick of the School of Dentistry, who headed the project, told The Telegraph.

Another study by GlaxoSmithKline Consumer Healthcare found that a gourmet diet destroys tooth enamel with other acid foods, including balsamic vinegar, fruit teas and wine. In an October 2005 survey, 91 percent of British dentists said they had seen patients whose teeth had been harmed by acidic diets.

Copyright 2006 by United Press International. All Rights Reserved.


Diabetes gene at root of wider syndrome

Diabetes gene at root of wider syndrome

OXFORD, England, May 4 (UPI) -- British scientists say gene mutations associated with neonatal diabetes are believed responsible for other neurological dysfunctions.

The mutations of the KCNJ11 gene are involved in up to 50 percent of neonatal diabetes and studies suggest the same mutations cause a syndrome that can include developmental delay, epilepsy and muscle weakness.

In the study, Dr. Anna Gloyn and colleagues at Churchill Hospital in Oxford, England, present a novel mutation, C166F, in the gene KCNJ11. They show C166F, as well as two other known KCNJ11 mutations involved in diabetes, also lead to different features of the syndrome known as "developmental delay, epilepsy and neonatal diabetes," or DEND.

The researchers believe that as the gene is expressed in different tissues and muscles, the mutation results in neurological features separate from acute or chronic diabetes.

To date only three patients have been identified with a KCNJ11 mutation as well as developmental delay and epilepsy. The patient involved with the C166F mutation resulting in full DEND is the fourth, and supports the thesis that the particular clustering of features is due to these mutations, the scientists said.

The study is presented online by the European Journal of Human Genetics.

Copyright 2006 by United Press International. All Rights Reserved.


British woman pregnant at age 63

British woman pregnant at age 63

LEWES, England, May 4 (UPI) -- A 63-year-old British child psychiatrist has announced she's seven months pregnant after successful in vitro fertilization at an Italian clinic.
Patricia Rashbrook, who has two adult children, spent about $90,000 for the treatment in Rome last October by controversial gynecologist Severino Antinori, The Times of London reported Thursday.

Antinori has made the news for his work with post-menopausal women and attempts at human cloning.

Meanwhile, Rashbrook and her 61-year-old husband, John Farrant, told The Sun they were looking forward to the birth.

An unnamed friend of the couple told the newspaper Rashbrook is considering going back to work after the child is born.

"She may be 63, but she has the energy of a woman 20 years younger," the friend said.
The world's oldest mother is believed to be Adriana Iliescu, of Romania, who had a daughter at the age of 66 last year.

Copyright 2006 by United Press International. All Rights Reserved.


Disease-carrying insects move north

Disease-carrying insects move north

BOSTON, May 4 (UPI) -- As the Earth warms, insects that carry disease are spreading into new areas, bringing the West Nile virus to Canada and malaria to high valleys.
Dr. Paul Epstein, who teaches at Harvard Medical School and once worked in Africa, said the shift is coming faster than physicians anticipated.

"Things we projected to occur in 2080 are happening in 2006," he told The Washington Post. "What we didn't get is how fast and how big it is, and the degree to which the biological systems would respond. Our mistake was in underestimation."

The World Health Organization says at least 30 diseases are either new or making comebacks because of climate change, a shift in the pattern of infectious disease unlike anything seen since the Industrial Revolution.

Epstein and his colleagues, in a report late last year, said cold areas are more sensitive to climate change than warm ones and insects are very sensitive to higher temperatures.

Copyright 2006 by United Press International. All Rights Reserved.