IMMUNIZING THE HEART
Vaccine against heart disease lowers risk by 70 percent in initial animal tests, may be ready for humans in two years
Gene linked to Tourette syndrome
WASHINGTON
A mutated gene may trigger the twitching and vocal tics of Tourette syndrome, according to scientists at Yale University Medical School who discovered a gene that when mutated may lead to a small number of cases of the neurological disorder.
Historically researchers, believing Tourette was caused by a single faulty gene, searched for genetic similarities among large groups of patients. Yale scientists took an opposite approach, finding one boy with Tourette who also had a chromosomal anomaly that might suggest involvement of certain genes.
A DNA analysis on the boy found the SLITRK1 gene expressed near the abnormality. To test the gene's association with Tourette, scientists compared the boy's mutated gene with the same gene in 174 other people who also had Tourette.
Findings showed a family that had an abnormal gene sequence. Two unrelated people also had an identical, rare change in the DNA sequence in an area of the gene that is not responsible for making protein. However, this gene segment did alter a binding site for microRNAs, small particles that regulate gene expression. The variants were absent in the 3,600 non-Tourette chomrosomes tested.
Senior author Matthew State, a genetics professor at Yale, said the gene could provide clues to understanding Tourette syndrome on a cellular and molecular level. Found on chromosome 13, the SLITRK 1 gene, which in healthy people helps neurons grow, is normally expressed in a few different areas of the brain. Scientists found that in a small number of Tourette cases, the mutation of the gene alters protein function.
The findings are reported the October 14 issue of Science.
Marijuana could improve memory, mood
OTTAWA
Canadian researchers have discovered that smoking marijuana could improve a person's memory and mood. A team at the University of Saskatchewan headed by Xia Zhang found that injections of a potent HU210 synthetic substance that mimics the active ingredients in cannabis increases the production of neurons in the hippocampus area of the brain in rats. The region is associated with learning and memory, as well as anxiety and depression. Zhang and his colleagues believe that these negative emotions are caused by a lack of cell growth in this region of the brain.
"The implication is that smoking marijuana is a good thing," Zhang said. The discovery may eventually lead to the next blockbuster antidepressant drug treatment, he said. "It is possible this might overtake Prozac," he said.
Of course, it has only been proved in rats so far. And, HU210 is a purified substance 100 times stronger than the active ingredient tetrahydrocannabinol in marijuana.
The study will be published in the Journal of Clinical Investigation in November.
Genetically modified mosquitoes could fight malaria
LONDON
Mosquitoes with fluorescent testicles may be the key to fighting malaria. Scientists at Imperial College London created the genetically modified male insects, which could be bred, sterilized, and released into the wild to mate with females and eradicate natural mosquito populations, carriers of the deadly malaria parasitic disease.
Eliminating mosquito populations could save thousands of lives in Africa, Asia, and South America where malaria is most common.
The scientists, led by Prof. Andrea Crisanti, created the gene that gives male mosquitoes fluorescent testicles in order to distinguish between the sexes more easily. Male mosquitoes do not bite, so they can be released to mate with the female population while posing no danger to humans. If enough sterile males are released into the wild, a mosquito population could be controlled within weeks, according to the study published Nature Biotechnology.
"Female mosquitoes are responsible for spreading malaria, and also for damage to crops, but they are only able to breed once before dying," Crisanti explained. "By forcing females to breed with sterile males, we can stop them from creating additional mosquitoes and at the same time, reduce the population."
The research team used a sorting machine to separate males from females based on lasers picking out a fluorescent green protein in the male gonads. The machine could sort 180,000 larvae in 10 hours, making feasible a large-scale release of the millions of modified mosquitoes needed to control the population.
Exercise in middle age lowers Alzheimer risk
LONDON
Reducing one's risk of developing Alzheimer disease may be as simple as going for a brisk walk.
Research published in Lancet Neurology found that middle-aged people who exercise are much less likely to develop dementia or Alzheimer disease later in life. The study by Swedish scientists said that people who exercised at least twice a week for 20 minutes reduced their risk of developing Alzheimer by 60 percent compared with people who did little physical activity, and lowered their chances of having dementia by 50 percent.
"These findings may have wide implications for preventive health care," said Dr. Miia Kivipelto of Sweden's Karolinska Institute, who led the study. "If an individual adopts an active lifestyle in youth, at midlife, this may increase their probability of enjoying both physically and cognitively vital years later in life."
Exercise had even more pronounced effects for people who were genetically susceptible to Alzheimer disease, the study also found.
Researchers checked for dementia or Alzheimer in 1,449 people ages 65 to 79 whose exercise activities had been monitored since 1972. Exercise may improve blood flow in the brain, the researchers say, and protect against conditions like high blood pressure that make dementia more likely.
Cloned piglets for organ transplants
SEOUL
South Korean scientists have successfully cloned piglets whose organs were genetically modified to make them more suitable for human transplants.
Lead scientist Park Kwang-Wook said the cloned piglets were genetically modified to contain the "HLA-G" gene, which would give their organs a greater chance of being accepted if they were transplanted into humans. He said he had injected the gene into the cell of a pig bred for organ transplants. The cell was then implanted into the womb of a surrogate pig that gave birth to five cloned piglets of which one survived.
Immunorejection has been a major hurdle in human organ transplant. Ordinary islet cells from pigs die after transplantation into humans due to the toxicity in the body's natural killer cells.
"But the cell with the HLA-G gene can reduce up to 70 percent of the toxicity," said Park.
"Mind-talk" device for paralysis sufferers
TOKYO
Japanese companies have developed a device that allows patients suffering from severe muscular paralysis to communicate "yes" or "no" by measuring blood flows in their brains.
The product called "Kokoro-gatari" (Mind-talk) was developed jointly by Hitachi, Excel of Mechatronix Corp., and Japan ALS Association for patients in the severest stage of amyotrophic lateral sclerosis (ALS).
ALS is a disease of motor neurons--muscle-controlling nerve cells--that ultimately affects all voluntary muscles, making patients incapable of even the slightest movements such as blinking.
The companies made use of one function the patients can control--blood flows in their brains. Although sufferers ultimately lose the power to move and speak, they continue to think normally.
With the device a patient wears a headband that emits near-infrared rays to measure blood flow. If they want to say "yes" to a question, they can activate the brain by calculating or singing a song mentally, which causes blood to gather in the frontal lobe. The device detects the increased blood flow. When patients want to say "no," they would just stay relaxed to keep the flow unchanged. An answer, about 80-percent correct on average, would come in 36 seconds.
The project started with a telephone call to Hitachi in 1999 by a man who was taking care of his wife in an advanced stage of ALS, according to Kensuke Yanagita of the ALS Association.
"Caregivers are always wondering if what they have done is okay to patients ... as there is no way to confirm it," said Yanagita. "You may think the accuracy rate is 20-percent less than perfect but it is a big leap from zero for us. At least caregivers would be able to know the patient is feeling good or not," he said.
The developers hope to market the device by the end of the year with a price tag of US$4,200.
Researchers developing vaccine for heart disease
STOCKHOLM
Researchers in the United States and in Sweden are working together to develop the world's first vaccine against heart disease.
"We have produced a simple form of vaccine that has worked well on test animals.… Now we're trying to develop it into a vaccine that has the quality and safety needed to use on humans," disclosed Prof. Jan Nilsson of Lund University in southern Sweden.
The idea for the vaccine emerged just over a decade ago when Nilsson and US researcher Prediman Shah of the University of California, Los Angeles (UCLA) were studying low-density lipoproteins (LDL), which cause most heart attacks and strokes. High levels of LDL tend to lead to oxidation in the blood vessels. Then plaque forms and sticks to the walls of the arteries.
"The body creates antibodies to this process. At first we thought they contributed to making the illness worse," Nilsson said, adding that they soon discovered that "the body works to remove the dangerous elements."
After isolating the active substance in the antibodies, Nilsson and Shah developed a vaccine that in test animals reduced the risk of heart disease by 70 percent.
"The vaccine simply strengthens the protection that already exists in the body," Nilsson said, adding "I think we'll have a human vaccine ready in two to three years."
He cautioned, however, that the results may not be quite as good as in the tests. "We'll be happy if we manage to bring down the risk [of heart disease] by between 30 and 50 percent," he said.
Diabetes test not working for Asians
HONG KONG
Experts fear a diabetes test is failing to detect the disease in thousands of Asians who may be unaware they have the condition. Researchers at Hong Kong Chinese University said they believed the test, which worked well with Caucasians, was not suited to Asian subjects.
"Although [the test] is often used to diagnose diabetes, increasing data suggest that this value is not sensitive enough to detect [the disease] especially in the Oriental population," they said.
"It's possible people have been tested and given the all-clear but could be carrying the illness," Chan Wing-bun, part of the university research team, said, noting that the differences in reactions among ethnic groups was baffling. "We believe it is probably because of the genetic differences between Caucasians and Asians, but we cannot be sure."
The study tested 230 Hong Kong people with high blood pressure, and found that a quarter had undiagnosed diabetes. However, only 60 percent of sufferers were detected to be diabetic through the regular test recommended by the World Health Organization. The rest were detected with a more time-consuming and expensive test.
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