 Let "Nemo" Ease the Pain
Experimental drug acts as vaccine against diabetes
CLOSING IN ON ALZHEIMER'S
SEATTLE, Washington
Changes in a neuron's fats trigger degeneration leading to Alzheimer's disease, scientists are learning, and they hope the new clues can help avoid the onset of dementia.
The concentration of cholesterol and other lipids in the brain could tip a "neurodegenerative cascade" that usually destroys neurons and causes Alzheimer's disease, said the scientists who presented their research before the American Association for the Advancement of Science.
The study concludes that this accumulation of lipids is caused by the presence of peptide beta amyloids, a key component of amyloids that form plaques attributed to the process of ageing. The presence of peptides could lead to an accumulation of cholesterol or ceramide that in turn could kill neurons.
"We had suspected that changes in fat metabolism in the membranes of nerve cells played a role in Alzheimer's, but we had not been able to establish a direct link," explained Mark Mattson, who led the study. "With this study, we have been able to illustrate how alterations in membrane lipids can lead to neuronal dysfunction and death."
The study may also explain why antioxidants like Vitamin E may delay the onset of Alzheimer's. The authors showed that vitamin E reduced the level of ceramide and cholesterol in neurons, which resulted in fewer killed neurons in mice.
The researchers also detected higher levels of ceramide and cholesterol in one area of the brain in people with Alzheimer's. "The involvement of cholesterol and ceramide in the neurotoxic actions of beta amyloid, and their strong associations with the way the Alzheimer's progresses, suggests a novel approach for therapeutic interventions," said Mattson.
BREAKTHROUGH IN SARS VACCINE RESEARCH
WASHINGTON
US researchers have discovered that a mouse's immune system produces antibodies that can neutralize the SARS virus, a finding that could boost research for a vaccine to stop the deadly disease. Initial experiments by the National Institute of Allergy and Infectious Diseases (NIAID) showed that mice could be infected with SARS without getting sick, the Journal of Virology reported in its April 1 issue.
The virus infected cells lining the mice's airways and lungs to reproduce itself. After being given a second dose of SARS 28 days later, the mice produced antibodies against SARS and the virus did not reproduce itself in the animals' lungs and airways. The first infection protected the mice from a second infection, researchers found. The third experiment showed that the antibodies produced by mice with SARS could be transferred to mice not infected with the virus, making them immune against the disease. The SARS virus could not reproduce itself in the mice that were given the antibodies.
"This 'passive immunity' demonstrated that antibodies alone prevented the mice from becoming infected," the SARS said.
"Since SARS emerged in people in late 2002, global public health experts have been anxiously awaiting a vaccine for this potentially fatal respiratory ailment," said SARS director Anthony Fauci. "Knowing which arm of the immune system to trigger brings us one step closer to that goal."
Kanta Subbarao, the study's lead author, said the discovery "is good news for people developing vaccines that would prime the immune system to produce antibodies against the SARS virus. "Our results also indicate that drug researchers can use laboratory mice as a model to evaluate whether a drug blocks SARS," he added.
DNA VACCINE SHOWS PROMISE
PARIS
A new trial vaccine against SARS has yielded extremely promising results on lab mice, its designers report in Nature. The prototype greatly stimulated antibodies and "killer" immune cells in the rodents, and levels of the SARS virus in vaccinated rodents exposed to the microbe were kept at almost negligible levels.
The formula, developed by the US-NIAID, is a so-called DNA vaccine. Under this, a snippet of DNA coating for a "spike" on the outer surface of the SARS virus was stitched into a cellular component called a plasmid and injected into mice muscle.
The experimental vaccine has yet to be tried on humans, but the first technical steps toward this have been taken pending authorization from the US Food and Drug Administration.
At least 10 candidate vaccines against SARS are under development in Asia, Europe, and the US. Leading the pack is a prototype from China that uses a killed virus to provoke an immune response. The trial vaccine has been successfully tested on monkeys, and China has launched an assessment for safety on 30 human volunteers.
GENE VARIATION SHOWS RISK OF DIABETES...
BETHESDA, Maryland
A team of international researchers said they have identified a genetic variation that appears to increase the risk of adult-onset diabetes, said a study published in the April issue of Diabetes.
During studies of chromosome 20-recognized as having a role in the onset of diabetes-two teams of researchers identified four genetic variations on a gene, dubbed HNF4A, which appears to have a strong link with the appearance of diabetes in people studied in Finland and Israel.
"The prevalence of type 2 diabetes in the United States is 6.7 percent. With this variation, your risk is close to 10 percent," explained Dr. Francis Collins, director of the National Human Genome Research Institute of the National Institutes of Health. "If you have this variation, it appears to raise your risk of type 2 diabetes about 30 percent," but only in combination with yet-to-be-identified genetic susceptibility factors, said Collins.
"This is an outstanding example of how scientists are using the tools of modern biology to understand the causes of our nation's most common and most devastating diseases," said Elias Zerhouni, director of the NIH.
Earlier, researchers announced success in detecting defects in proteins regulating genes in the pancreas and liver, factors in the development of type 2 diabetes. Their technique consisted of analyzing the human genome to detect the defects in the proteins affecting the genes in the pancreas and the liver, organs important to the onset of diabetes.
...DRUG MAY HEAD OFF TYPE 1
LOS ANGELES
An experimental medicine acts like a vaccine against type 1 diabetes in mice and may do the same for humans.
The newly created compound, called ISO-1, seems to reduce the inflammation that causes the disease in mice, scientists said at the American Chemical Society conference in Anaheim, California in March. The mice were given ISO-1 for 10 days; at the same time they received a drug that promotes the onset of diabetes. Nonetheless, the mice were completely protected.
"We believe this is the most promising compound to date for preventing type 1 diabetes," study leader Yousef Al-Abed said. "If it works, it will be especially beneficial for young people, who often have a difficult time managing their diabetes with daily insulin injections."
Physicians can detect which children are in danger of developing diabetes with blood tests. They hope the new drug could head off the disease.
"X" MARKS THE SPOT FOR AGEING
PARIS
The hunt for a suspect in the ageing process is narrowing, according to new research that points the finger at the X chromosome, one of the two chromosomes that determine gender.
Ageing is widely believed to be governed by tiny nubs called telomeres, found at the end of chromosomes-the lengths of coiled DNA that contain genes. Every time a cell divides, the telomeres become shorter. After successive cell replication, telomeres become so worn that no more divisions can take place, which means that tissue is not replaced when it reaches the end of its functional life.
Belgian scientists, reported The Lancet, checked the telomere lengths in white blood cells taken from several hundred volunteers in Flanders, northern Belgium. They discovered that telomere lengths were similar between fathers and daughters, mothers and sons, mothers and daughters, and among siblings-but there was no similarity among fathers and sons or between spouses.
That points to an inherited cause, and more specifically the X chromosome, the researchers say.
Females have two X chromosomes, both of which come from their parents. Males have an X, which is inherited from their mother, and a Y chromosome, which comes from their father.
"Our observations suggest that the process of ageing might be an X-linked trait," the team, led by Jan Staessen of the University of Leuven, say. Staessen admits more work is needed to confirm this but suggests there are already some interesting genes on the X chromosome that are likely to play a role in how quickly telomeres shorten.
One is a gene called DKC1, which encodes a protein, dyskerin, that is important in stabilizing telomerase.Telomerase is an enzyme that replenishes telomeres. Another is AGTR2, which has a role in production of nitric oxide, a chemical known to slow cellular ageing.
The study also found that, matched age for age, women had longer telomeres than men, which sheds light on why women generally outlive men. The female hormone estrogen could be important in that regard, for it can stimulate telomerase, the authors speculate.
COLOR MY PAIN
BOGOTÁ, Colombia
French scientist Yves Loones, chief executive of Physiolab, has developed a machine that treats wounds by emitting colored lights. Called "Nemo," the machine has been brought by Loones to Bogotá's Central Military Hospital where he is treating victims of Colombia's civil war.
The color therapy "is ideal for the treatment of war wounds in a country like Colombia," said Loones, who served as a United Nations peacekeeper in Lebanon in 1981.
It took his lab, based in Sable-sur-Sarthe in western France, eight years to develop Nemo, which is the size of an exercise bike. The light emitted by Nemo is not invasive, he said. "Each color that is used does not emit any heat," he said. "Therefore there is no risk of burning tissue, unlike X-rays."
In a meeting with military hospital doctors, Loones showed photographic slides of a French car accident victim whose injured hands suffered from hypothermia. After two Nemo sessions lasting a total of 32 minutes, the temperature of the victim's hands increased by eight degrees Celcius. Nemo has shown that it can reduce pain by 60 percent and replace antiinflammatory medicine, he said.
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