Squid beaks may have medical application
Fri, 28 Mar 2008 01:11:19 GMTBy RANDOLPH E. SCHMID, AP Science Writer
WASHINGTON - The razor-sharp beaks that giant squids use to attack whales — and maybe even Captain Nemo's submarine — might one day lead to improved artificial limbs for people.
That deadly beak may be a surprise to many people, and has long posed a puzzle for scientists. They wonder how a creature without any bones can operate it without hurting itself.
Now, researchers at the University of California, Santa Barbara, report in Friday's edition of the journal Science that they have an explanation
The beak, made of hard chitin and other materials, changes density gradually from the hard tip to a softer, more flexible base where it attaches to the muscle around the squid's mouth, the researchers found.
That means the tough beak can chomp away at fish for dinner, but the hard material doesn't press or rub directly against the squid's softer tissues.
Herbert Waite, a professor in the university's department of molecular, cellular & developmental biology and co-author of the paper, said such graduated materials could have broad applications in biomedical materials.
"Lots of useful information could some out of this for implant materials, for example. Interfaces between soft and hard materials occur everywhere," he said in a telephone interview.
Frank Zok, professor and associate chair of the department of materials, said he had always been skeptical of whether there is any real advantage to materials that change their properties gradually from one part to another, "but the squid beak turned me into a believer."
"If we could reproduce the property gradients that we find in squid beak, it would open new possibilities for joining materials," Zok said in a statement. "For example, if you graded an adhesive to make its properties match one material on one side and the other material on the other side, you could potentially form a much more robust bond."
The researchers are learning lessons that can be applied to medical materials in the future, said Phillip B. Messersmith of the department of biomedical engineering at Northwestern University.
Messersmith, who was not part of the research team, noted that hard medical implants made of metal or ceramic are often imbedded in soft tissues.
"The lessons here from nature might be useful in transitions between devices and the tissues they are imbedded in," he said in a telephone interview.
Ali Miserez, a UCSB researcher and co-author of the paper, suggested the research could point the way to new types of medical materials.
"We could maybe imagine creating a full prosthesis that mimics the chemistry of the beak, so that it matches the elasticity of cartilage on one side and, on the other side, you could create a material which is very stiff and abrasion resistant," he said in an interview provided by Science.
Waite described the squid beak as like placing an X-Acto blade in a block of fairly firm Jell-O and then trying to use it to chop celery.
The base of the blade would damage the gelatin, but because of the change in density the base of the beak doesn't damage the squid, he pointed out. The squid solves the problem by changing the beak composition progressively, rather than abruptly, so that its tip can pierce prey without harming the squid in the process.
The researchers calculated the changes by carefully measuring the ratios of chitin — the material in insect shells — water and proteins in the beaks of Humboldt squid, showing gradual changes from tip to base.
Waite said it was the first time this had been measured. He said he was surprised that the main difference in density resulted from the amount of water included in each part of the beak.
Most people probably know squid best as fried calamari — the tasty starters popular in many restaurants. But the researchers noted that these are animals that deserve respect.
"Squids can be aggressive, whimsical, suddenly mean, and they are always hungry," Waite said. "You wouldn't want to be diving next to one. A dozen of them could eat you, or really hurt you a lot."
And they are very fast, swimming by a sort of jet propulsion.
The research was funded by the National Institutes of Health, National Science Foundation, NASA and the Swiss National Science Foundation.
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On the Net:
Science: http://www.sciencemag.org
EU threatens ban on Italian mozzarella
Thu, 27 Mar 2008 22:36:18 GMTBy CONSTANT BRAND, Associated Press Writer
BRUSSELS, Belgium - The European Union ordered Italy on Thursday to take "urgent measures" to make sure mozzarella tainted with dioxin does not end up on store shelves, warning that otherwise it would impose an EU-wide ban on the popular cheese.
The European Commission said Italian health officials had not taken sufficient steps to guard against health problems, such as recalling potentially tainted cheese or doing enough monitoring of affected farms in the Campania region.
The scare involves only mozzarella from the Naples area, which is in a months-old crisis over garbage collection and disposal that has fueled fears of food contamination. But the EU's warning covers all of Campania, the southern farm region where the soft, milky cheese is made.
Many experts have said no direct link has been established between the garbage problem and the contamination of cheese, which involves samples being found with higher concentrations of the toxic chemical dioxin than allowed under EU food safety rules.
Dioxin, which occurs naturally but is also a byproduct of some manufacturing processes, is best known for causing skin disfigurement but has been linked to cancer, birth defects and organ failure. It can be dangerous even in small amounts.
The European Commission, the administrative body of the EU, complained that "no recall of products potentially contaminated has been carried out" by Italy. It also said surveillance of affected farms was "too limited."
"Therefore, the Commission has requested the Italian competent authority to take further urgent measures," its statement said.
EU spokeswoman Nina Papadoulaki warned that the EU might consider a full ban on mozzarella sales. "If we don't get everything that we want ... we will see whether further or any measures need to be taken," she said.
She also said that while the contamination exceeded EU standards, "it was not excessive."
In Rome, Health Ministry officials insisted Italy was complying with all EU rules.
Italian officials said Wednesday they had temporarily shut down production at more than 80 cattle farms after detecting higher-than-permitted levels of dioxin in 25 mozzarella-making facilities out of 130 checked.
They said the dioxin was likely coming from contaminated cow feed.
The milk is being destroyed and authorities are carrying out further checks on farms in southern Italy to determine how the feed got contaminated, the officials said.
Earlier this year, Naples health authorities began screening residents for dioxin amid accusations that toxic garbage was being dumped illegally by Mafia-controlled garbage haulers. It is not clear if toxic garbage has played any role in the mozzarella contamination.
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Associated Press writers Alessandra Rizzo and Marta Falconi in Rome contributed to this report.
Dengue claims 54 lives in Brazil
Thu, 27 Mar 2008 21:29:38 GMTBy MICHAEL ASTOR, Associated Press Writer
RIO DE JANEIRO, Brazil - A dengue epidemic has claimed at least 54 lives in Rio de Janeiro state since January, health officials said Thursday.
Hospitals have reported a total of 114 deaths from the mosquito-borne disease, but 60 of those cases are still being investigated.
Brazilian Health Care Secretary Jose Noronha said that 1,200 soldiers from the army, air force and navy would be deployed next week to set up three field hospitals, while an additional 500 would spray insecticide and place poison in standing puddles of water where the mosquitoes breed.
"The intensity of the epidemic has brought intolerable death tolls," Noronha told reporters after a meeting with armed forces commanders.
The majority of the confirmed deaths, 31, have been in the city of Rio de Janeiro — Brazil's biggest resort city. Rio has seen a 25 percent drop in tourism as a result, the Brazilian Hotel Association said.
About half of the victims were children under the age of 13.
More than 43,000 people have contracted disease since January in Rio de Janeiro state — nearly double the 25,107 cases reported in all of 2007. The state is home to 16 million people.
State health official Victor Berbara said the outbreak highlights the importance of fighting the dengue-carrying Aedes aegypti mosquito all year — not just between November and May when most infections occur.
"If nothing is done ... next year is going to be much worse," he told reporters.
Earlier this week, federal officials sent hundreds of health workers to Rio de Janeiro state to help care for victims in the state's overcrowded emergency rooms, and set up special tents with extra hospital beds in the city.
On Wednesday, Rio de Janeiro state Gov. Sergio Cabral ordered health officials to break into homes suspected of containing standing bodies of water if the owners could not be found.
Dengue, which has no vaccine, can incapacitate patients for over a week with severe headaches and joint pains, but is not usually fatal.
Big belly boosts risk of later dementia
Thu, 27 Mar 2008 21:26:27 GMTBy MALCOLM RITTER, AP Science Writer
NEW YORK - Having a big belly in your 40s can boost your risk of getting Alzheimer's disease or other dementia decades later, a new study suggests.
It's not just about your weight. While previous research has found evidence that obesity in middle age raises the chances of developing dementia later, the new work found a separate risk from storing a lot of fat in the abdomen. Even people who weren't overweight were susceptible.
That abdominal fat, sometimes described as making people apple-shaped rather than pear-shaped, has already been linked to higher risk of developing diabetes, stroke and heart disease.
"Now we can add dementia to that," said study author Rachel Whitmer of the Kaiser Permanente Division of Research in Oakland, Calif.
She and others report the findings in Wednesday's online issue of the journal Neurology.
The study involved 6,583 men and women who were ages 40 to 45 when they had checkups between 1964 and 1973. As part of the exam, their belly size was measured by using a caliper to find the distance between their backs and the surface of their upper abdomens. For the study, a distance of about 10 inches or more was considered high.
The researchers checked medical records to see who had developed Alzheimer's or another form of dementia by an average of 36 years later. At that point the participants were ages 73 to 87. There were 1,049 cases.
Analysis found that compared to people in the study with normal body weight and a low belly measurement:
• Participants with normal body weight and high belly measurements were 89 percent more likely to have dementia.
• Overweight people were 82 percent more likely if they had a low belly measurement, but more than twice as likely if they had a high belly measurement.
• Obese people were 81 percent more likely if they had a low belly measurement, but more than three times as likely if they had a high measurement.
Whitmer said there's no precise way to translate belly measurements into waist circumference. But most people have a sense of whether they have a big belly, she said. And if they do, the new study suggests they should get rid of it, she said.
It's not clear why abdominal fat would promote dementia, but it may pump out substances that harm the brain, she said.
Dr. Jose Luchsinger of the Columbia University Medical Center in New York, who studies the connection between obesity and Alzheimer's disease but didn't participate in the new work, cautioned that such a study cannot prove abdominal fat promotes dementia.
But the study results are "highly plausible" and "I'm not surprised at all," he said. High insulin levels might help explain them, he said.
Dr. Samuel Gandy, who chairs the medical and scientific advisory council of the Alzheimer's Association, said the results fit in with previous work that indicates a person's characteristics in middle age can affect the risk of dementia in later life.
And it's another example of how traits associated with the risk of developing heart disease are also linked to later dementia, he said.
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On the Net:
Neurology: http://www.neurology.org
Alzheimer's Association: http://www.alz.org
Whitmer Web site: http://www.dor.kaiser.org/staff/investigators/whitmer.shtml
