origin of disease: no link found between AIDS and polio vaccine

Posted on April 27, 2004 by agnieszka

An international team of researchers refutes the controversial theory that the AIDS virus, HIV-1, jumped into humans from contaminated polio vaccines. Proponents of the theory stated that a group of chimpanzees from the Kisangani region in the Democratic Republic of Congo were infected with a monkey form of the immunodeficiency virus. These infected chimpanzees’ tissues were then allegedly used to prepare oral polio vaccines given to humans — thereby allowing the virus to cross over into people. Michael Worobey of the University of Arizona and his colleagues argue in the April 22 Nature, however, that the theory can’t be true. His team tested wild chimps from the same area and found that while the virus is indeed prevalent among the animals, molecular analysis showed it to be so different from all strains of HIV-1 that it provides “direct evidence that these chimpanzees were not the source of the human AIDS pandemic.” Worries about the safety of the vaccine is hampering the global eradication of polio. The authors hope that their findings will finally lay the theory — and the fears it inspires — to rest.

This news brief appeared in the Discoveries column of the Boston Globe’s Health/Science section on 4/27/2004.
Posted in boston globe, news briefs | Comments Off on origin of disease: no link found between AIDS and polio vaccine

literacy: good teachers have power to change brains

Posted on April 27, 2004 by agnieszka

Brain-imaging studies show that effective teaching can make the brains of poor readers function like those of fluent readers. Bennett Shaywitz of Yale University and his colleagues report in the May 1 issue of Biological Psychiatry that they scanned the brains of 77 children between the ages of 6 and 9 as they read. Of the poor readers in the group, some had standard instruction in reading, while others were enrolled in an intensive reading program focusing on phonics and phonemes, the individual sounds that make up words. The students in the intensive program made strong gains inreading accuracy, comprehension, and fluency over the school year compared to the poor readers in the standard program, and their brain scans showed increased activity in an area of the brain that recognizes words automatically without first having to puzzle them out, similar to the brain scans of good readers. In a press release, coauthor Sally Shaywitz said the study shows that “teaching matters and good teaching can change the brain in a way that has the potential to benefit struggling readers.”

This news brief appeared in the Discoveries column of the Boston Globe’s Health/Science section on 4/27/2004.
Posted in boston globe, news briefs | Comments Off on literacy: good teachers have power to change brains

evolution and behavior: girls learn while boys play

Posted on April 20, 2004 by agnieszka

Girl chimps learn faster than boy chimps, according to a new study with human parallels appearing in the April 15 Nature. Elizabeth Lonsdorf of the University of Minnesota and colleagues studied how young, wild chimpanzees in Gombe National Park in Tanzania learned to use sticks to fish for termites, a rich source of protein. The researchers found distinct sex-based differences in the chimps, similar to the differences found in human boys and girls learning a new skill, such as writing. The girl chimps spent more time watching their mothers fishing than the boys, who spent most of their time “playing around the termite mound.” (Not that playing is bad; roughhousing may help them in typical adult-male activities, such as hunting.) But, by closely observing their mothers and copying their actions almost exactly, the girl chimps learned how to fish for termites much earlier than boys, and also caught more termites with each attempt. The researchers write that the study is the first systematic evidence of a difference between the sexes in the learning of a tool-use technique in chimps, and implies that sex-based learning differences may “date back at least to the last common ancestor of chimpanzees and humans.”

This news brief appeared in the Discoveries column of the Boston Globe’s Health/Science section on 4/20/2004.
Posted in boston globe, news briefs | Comments Off on evolution and behavior: girls learn while boys play

economics and biology: americans are losing the height race

Posted on April 20, 2004 by agnieszka

Not only are we as a nation getting fatter, but it also appears that, in contrast to other countries, we’ve stopped growing taller. John Komlos of the University of Munich analyzed more than 200 years’ worth of data on height for the March issue of Economics and Human Biology and found that Americans were the tallest people in the world up until about World War II, but now Europeans have outpaced us. In the middle of the 19th century, for example, Americans towered over the Dutch by an average of 2 to 3 inches. Now the Dutch tower over us by the same amount. (American men currently average about 5 feet 10 inches tall, while the Dutch average 6 feet 1 inch.) Today Danes, Brits, Germans — even East Germans — are taller on average than Americans. Physical stature is considered a useful way to measure biological well-being, revealing details of upbringing, nutrition and health care, particularly during childhood and adolescence. Considering that the United States is the richest nation in the world, the finding is rather surprising. Komlos speculates in his study that the “adverse development” could be due to “the greater social inequality, an inferior health care system, and fewer social safety nets in the United States than in Western and Northern Europe.”

This news brief appeared in the Discoveries column of the Boston Globe’s Health/Science section on 4/20/2004.
Posted in boston globe, news briefs | Comments Off on economics and biology: americans are losing the height race

fat really does bring pleasure

Posted on April 13, 2004 by agnieszka

The sensation of fat in the mouth activates the reward centers of the brain, report British researchers in the March 24 Journal of Neuroscience in a finding that sheds light on why high-calorie foods are so appealing and might lead to healthier fat substitutes. Ivan de Araujo and Edmund Rolls of the University of Oxford fed 12 people differently textured bland foods from tubes as they scanned their brains using a functional magnetic-resonance-imaging machine. The volunteers were fed cellulose — an odorless and tasteless thickening agent — mixed to a variety of viscosities, and an odorless and tasteless vegetable oil. The researchers found that the thicker solutions activated an area of the brain that overlaps a region known to be triggered by taste, hinting that the brain builds a picture of food in the mouth based on both taste and texture. Interestingly, the researchers also discovered that the bland vegetable oil activated the anterior cingulate cortex, a region of the brain involved with processing pleasurable sensations such as pleasant touches and aromas, where the tasteless cellulose, mixed to match oil’s viscosity, did not, suggesting there really is something special about fat that makes us crave it so much.

This news brief appeared in the Discoveries column of the Boston Globe’s Health/Science section on 4/13/2004.
Posted in boston globe, news briefs | Comments Off on fat really does bring pleasure

evidence for first pet cats discovered

Posted on April 13, 2004 by agnieszka

Researchers believe they have found the remains of the earliest known pet cat. Jean-Denis Vigne of the CNRS-Museum National d’Histoire Naturelle in Paris and colleagues report in the April 9 Science that they have discovered a human and a cat buried in close proximity in a Stone Age village on the Mediterranean island of Cyprus. The find demonstrates “that a close relation had developed by 9,500 years ago” between human and feline, thousands of years before the ancient Egyptians were generally believed to have domesticated the cat. The human grave contained rich offerings of polished stones, axes, and flint tools, and lay nearby a small pit with 24 sea shells. The cat was buried just 16 inches away from the human. The 8-month-old animal’s skeleton was intact and examination showed that the small grave had been dug deliberately. The authors write, “The burial of a complete cat without any butchering reminds us of human burials and emphasizes the animal as an individual.” Vigne added in a press release, “The association of this burial with both the sea shells and the cat grave strengthens the idea of a special burial indicating a strong relationship between cats and human beings. Possibly tamed cats were devoted to special activities or special human individuals in the village.”

This news brief appeared in the Discoveries column of the Boston Globe’s Health/Science section on 4/13/2004.
Posted in boston globe, news briefs | Comments Off on evidence for first pet cats discovered

lab rat’s code cracked

Posted on April 6, 2004 by agnieszka

To mice and men, add the common lab rat to the creatures whose genomes — or genetic blueprints — have been sequenced and decoded. A large international team of researchers known as the Rat Genome Sequencing Project Consortium reported their draft of the brown Norway rat’s genetic map in the April 1 issue of Nature. The researchers found that the rat genome is slightly smaller than the human, and slightly larger than the mouse, but that all three share about 25,000 to 30,000 genes. The rat genome should help shed light on the complicated genetic components of human physiology and illness, since almost all human genes linked to disease have been found to have counterparts in the rat, confirming its use as an excellent model for medical research. The team also found that rats, unlike mice, have genes that help them deal with toxins, and that evolutionary changes have occurred at a faster rate in rodents than in primates, suggesting that their genes may be more dynamic than our own.

This news brief appeared in the Discoveries column of the Boston Globe’s Health/Science section on 4/06/2004.
Posted in boston globe, news briefs | Comments Off on lab rat’s code cracked

fat-derived hormone rewires brain

Posted on April 6, 2004 by agnieszka

Perhaps people should start blaming their brains instead of their diets for their weight. A hormone, leptin, known to control appetite, appears also to rewire the brain’s weight-regulation centers in early life, researchers from Oregon Health and Science University report in the April 2 Science. Secreted by fat cells in the body, leptin controls feeding behavior by suppressing appetite. Richard Simerly and colleagues studied mice that were genetically engineered to be unable to produce leptin, and therefore became obese. The researchers found that the animals had disrupted nerve connections in the part of the brain that controls eating, but that, when injected with leptin as babies, their brain circuits developed normally. “The same hormone that helps regulate food intake later in life also regulates the formation of weight-control brain mechanisms very early in life,” Simerly stated in a press release. He added that leptin’s role during brain development could have lasting effects on an individual’s ability to regulate his or her body weight.

This news brief appeared in the Discoveries column of the Boston Globe’s Health/Science section on 4/06/2004.
Posted in boston globe, news briefs | Comments Off on fat-derived hormone rewires brain

physics: magnetic carbon is lightest solid ever

Posted on March 30, 2004 by agnieszka

Once upon a time, the only known forms of carbon were graphite and diamond. Buckyballs and nanotubes have been invented relatively recently, and now an international team of researchers has created yet another structure, which they have dubbed nanofoam. The extremely lightweight solid and its strange properties were discussed at the March meeting of the American Physical Society held in Montreal last week. Researchers at the Australian National University in Canberra blasted carbon with a high-powered, super-fast laser, creating clusters of carbon atomsthat were randomly interconnected into a weblike foam. The novel structure has the lowest density ever reported for a solid. Perhaps most unusual for a substance of pure carbon, nanofoam is strongly magnetic. The effect is present at room temperature, although it starts dissipating after a few hours. The researchers believe that nanofoam may have important applications for the emerging field of electronics called spintronics, as well as in medicine, where it could be used to enhance magnetic resonance imaging.

This news brief appeared in the Discoveries column of the Boston Globe’s Health/Science section on 3/30/2004.
Posted in boston globe, news briefs | Comments Off on physics: magnetic carbon is lightest solid ever

molecular biology: how green tea fights cancer

Posted on March 30, 2004 by agnieszka

Studies suggest that green tea has protective effects against many different kinds of cancers, including lung, breast, and prostate. The tea’s benefits have been widely attributed to a powerful antioxidant called EGCG, but researchers were unsure exactly how it worked. Now Hirofumi Tachibana of Japan’s Kyushu University and colleagues report in the April issue of Nature Structural & Molecular Biology that they have discovered that EGCG targets the laminin receptor, a protein found on the surface of tumor cells. The antioxidant binds to the protein and inhibits the cell’s growth. When the team treated human lung cancer cells expressing the protein with EGCG, they found that the growth of cancer cells slowed dramatically. The researchers say their findings suggest that drinking just two or three cups of green tea a day could be enough for EGCG to produce its effects.

This news brief appeared in the Discoveries column of the Boston Globe’s Health/Science section on 3/30/2004.
Posted in boston globe, news briefs | Comments Off on molecular biology: how green tea fights cancer