Researchers have found a pharmaceutical way to clear some of the cognitive fog that results from a sleepless night. In a new study using lab mice, researchers corrected the memory problems in sleep-deprived mice through a drug that suppressed levels of a certain enzyme in a brain region called the hippocampus, which plays an important role in memory and learning.
The study, published in Nature, helps tease out the specific effects of sleep deprivation on the brain. Says lead researcher Christopher Vecsey: “One of the main problems is that sleep deprivation does a lot of things to the brain, and it’s easy to get caught in a mish-mash of different effects” [Nature News].
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A team of researchers recently discovered that Tamiflu, the leading flu-fighting drug, is accumulating in rivers downstream from sewage-treatment plants in Kyoto. How is this possible? Tamiflu’s active ingredient, oseltamivir phosphate, is excreted in the urine of people taking the medication. Concerns are now building that birds, which are natural influenza carriers, are being exposed to waterborne residues of Tamiflu’s active form and might develop and spread drug-resistant strains of seasonal and avian flu [Science News]. The resistant virus strains would be of the conventional seasonal or avian flu variety, not the H1N1 swine flu strain that is currently pandemic in humans. Seasonal flu, however, kills thousands of people each year.
Study coauthor Gopal Ghosh explains that the team took measurements during normal flu season, and found concentrations that seem “high enough to lead to antiviral resistance in waterfowl” [Science News]. Computer models show that oseltamivir phosphate will survive sewage treatment, but it should break down when exposed to sunlight and its concentrations should decrease by half every three weeks. The high concentrations were found during a period where 1,738 flu cases were reported in Kyoto, according to the study, published in the journal Environmental Health Perspectives. In the United States, Tamiflu is only recommended for the very sick or those with compromised immune system, while Japan has a more liberal policy.
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Image: flickr / law_keven
Although researchers searching for an HIV vaccine have been down the path of optimism and disappointment many times before, a new finding has nevertheless brought fresh hope to the flagging effort. Researchers have discovered two antibodies that can effectively fight back most strains of the HIV virus, and say they’ll now try to make a vaccine that can teach the human body to produce these antibodies.
The weapons in question are called broadly neutralising antibodies…. These are antibodies that deactivate a wide range of HIV strains—which is particularly important for an effective vaccine, because HIV is so variable [The Economist]. Researchers found the two new antibodies after screening blood samples from 1,800 people around the world who were infected with HIV but hadn’t yet developed AIDS; the two antibodies both came from an African donor. Of these two potent antibodies, one neutralized 127 of 162 HIV strains and the other neutralized 119.
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Residents of the U.K. who go overseas for surgery have imported a new “superbug.” The bacteria, which is resistant to antibiotics and is even more difficult to treat than infamous infections such as MRSA, has killed two people and seriously sickened 18 others in the past year.
Britain’s Health Protection Agency has declared the infection “a notable public health risk” as the bacteria continues to pop up all over the U.K. In fact, 17 hospitals in Scotland and England have seen the infection, which is in the enterobacteriaceae family. Many of those contracting the superbug, which produces an enzyme that destroys even the most powerful antibiotics, have had cosmetic surgery, liver and kidney transplants in India and Pakistan [Daily Mail].
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Antiviral treatments such as Tamiflu should not be administered to children under the age of 12 because the risks of the drugs outweigh the possible benefits in lessening symptoms of swine flu, according to a study published in the British Medical Journal.
Although antiviral drugs can shorten the duration of the flu in children by an average of 1.5 days, they fail to fight certain effects of the infection, having little effect on the risk of asthma flare-ups, for instance. In fact, the drugs can bring dangerous side effects like vomiting, which can be dangerous because it puts children at risk of dehydration. In the research review, scientists looked at four trials of 1,766 children treated with antivirals, including 1,243 with confirmed flu, and three trials of 863 who were exposed to flu but didn’t exhibit symptoms and were treated with antivirals preventively. Only one trial looked at children with asthma [CBC]. Overuse of antivirals can also increase the risk of viral strains that become resistant to such treatments.
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The genome of an HIV virus is a truly twisted thing, but now for the first time researchers have traced its every fold and contour. By mapping its entire structure, they hope to gain a greater understanding of how the virus operates, and potentially accelerate the development of drug treatments [BBC News]. Usually geneticists focus on the sequence of genes that comprise an organism’s genome, but recent evidence suggests that the structure can also play a role in how it functions.
Like many other viruses, the HIV genome consists of single-strand RNA, rather than the double-stranded DNA found in most animals. Though scientists have identified HIV’s genes and their order, just one-fifth of its genome has been described in precise spatial detail. That’s important because genomes don’t look anything like the neatly linear, bar code-like pictures returned by basic sequencing techniques. In reality, genomes are arranged in intricate, three-dimensional loops and whorls. And just as a list of machines isn’t very useful without a description of their arrangement on a factory floor, structure matters [Wired.com].
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Malaria in Cambodia is becoming increasingly resistant to one of strongest anti-malarial treatment available, according to a study published in the New England Journal of Medicine. That could cause literally millions of deaths as malaria, already the world’s third-deadliest infectious disease, becomes unresponsive to remedies that once proved effective against the disease.
The drugs examined were derived from artemisinin, the basis of the most effective treatment for the bloodborne parasite that causes malaria. To study the treatment’s effectiveness, researchers compared the effects of artemisinin drugs in 40 malaria patients in western Cambodia and 40 patients in northwestern Thailand. On average, the patients in Thailand were clear of malaria parasites within 48 hours, compared to 84 hours for the Cambodian patients [HealthDay News]. That means the remedies were significantly less effective against the mosquito-transmitted parasite in Cambodia. Furthermore, in the time since the study concluded, healthcare workers have observed lengthened clearance times among malaria patients in southern Cambodia, indicating the resistant strain has already begun to spread.
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In September 2007, HIV research faced a serious setback: Scientists found that a promising HIV vaccine was actually increasing the rate of HIV infection, and the so-called STEP vaccine trial was immediately halted. The failure had a ripple effect, and caused researchers to call off another vaccine trial that operated on a similar principle. Since then, researchers have developed multiple explanations for why the vaccine upped the risk of infection. Now two new studies presented in Nature Medicine refutes the latest of these hypotheses, which gives researchers valuable information but ultimately leaves the mystery unsolved.
The recent theory held that some people responded more strongly than others to a component of the vaccine tested in the STEP trial, making them more vulnerable to HIV, which attacks immune cells that are actively responding to a pathogenic threat [Nature News]. Because the vaccine was constructed on the modified backbone of the virus that causes the common cold, the theory posited that white blood cells called helper T-cells jumped into action to combat this infectious particle. Unfortunately, HIV targets these T-cells, scientists reasoned, so vaccination actually gave HIV a larger target. This would explain why vaccination increased the risk of HIV infection.
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Laboratory mice who were given an immunosuppresant drug called rapamycin lived between 9 and 14 percent longer than mice who didn’t take the drug, according to a study in Nature. The drug, which was developed from bacteria found in Easter Island’s dirt, is the first pharmacological agent shown to enhance longevity in a mammal [Technology Review]. Even more remarkable, the mice weren’t given the drug until late middle age, showing rapamycin had effects even when taken later in life.
The drug is already used to suppress the immune systems of organ transplant patients, and it’s undergoing clinical testing as a possible cancer treatment. Rapamycin works by inhibiting the target of rapamycin (TOR) signaling pathway, which plays a role in the translating mRNA into proteins and inhibits processes that degrade cellular waste. The drug has been found to extend the life spans of yeast, fruit flies, and nematodes [The Scientist], but this is the first time it’s been shown to help mammals live longer. The drug boosted the lifespans of mice that were 600 days old at the time of treatment, the equivalent in age to a 60-year-old human. “That is very surprising to myself and to a lot of people,” [said pathologist Matt] Kaeberlein. “And it’s a very important result” [The Scientist]. However, it still isn’t clear exactly how the TOR signaling pathway is involved in the aging process.
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Researchers may have finally figured out the mechanism of the tragic birth defects caused by thalidomide, the drug taken by pregnant women in the late 1950s as a remedy for nausea: It is thought to have inhibited development of new blood vessels at a crucial stage in the pregnancy.
Women usually took the drug at about five to nine weeks into their pregnancy to combat morning sickness, a specific window that lead researcher Neil Vargesson says “is crucial as that is when the limbs of babies are still forming…. The blood vessels involved in this process, at this stage of pregnancy, are still at an immature stage when they rapidly change and expand to accommodate the outgrowing limb” [BBC]. The most common birth defects caused by thalidomide were babies born with stunted or malformed limbs.
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In a masterful work of “DNA origami,” researchers have created a nanoscale DNA “box” which can be opened with DNA “keys”. One day, such structures could be filled with drugs, injected into the blood, and then unlocked when and where the drugs are required [New Scientist]. Researchers say the boxes could also be used as minuscule environmental sensors that open or close in response to a stimulus, or as the logic gates of a DNA-based computer.
To accomplish this feat, described in a paper in Nature, researchers exploited the fact that complementary DNA bases–the fundamental building blocks of DNA’s double helix–attach to each other. To design the box, the researchers developed a computer program to generate a continuous single-stranded DNA sequence that, along with smaller DNA fragments that act as staples, would self-assemble into the desired shape. The sequence was devised with many complementary regions so that it would automatically fold into six roughly square accordion-like sheets–the sides of the box–based on DNA’s natural tendency to pair into double strands. The DNA staples, also driven by the pairing of complementary sequences, stitched the sheets’ edges together to form a hollow cube with a hinged lid [Technology Review]. The final product was a box that measured 42 by 36 by 36 nanometers, and had a cavity big enough to hold enzymes or virus particles.
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NASA hopes to send a “nano-satellite” the size of a bread loaf into orbit tomorrow, where it will conduct experiments on yeast to determine how the microorganisms behave in space. Weighing only 10 pounds, the tiny satellite called PharmaSat is scheduled to lift off on board a U.S. Air Force four-stage Minotaur 1 rocket late on May 5. Once aloft and free of the rocket, the satellite will circle the Earth at 17,000 mph while carrying a micro-laboratory packed with sensors and optical systems [ComputerWorld].
The satellite’s lab will autonomously conduct drug testing in orbit, treating the yeast with anti-fungal drugs to see if the yeast responds differently to treatment when it’s free of the Earth’s gravity. “There’s data that’s coming back from shuttle and space station missions that indicates something is changing microorganisms in a microgravity environment making them more varied,” said Bruce Yost, PharmaSat mission manager…. Those genetic changes could make bacteria more resistant to antibiotics and medical treatment — something scientists are hoping to learn more about before attempting longer jaunts into space such as to the moon and beyond [The Register]. One recent study found that salmonella become more virulent after just 83 hours of growing in space.
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The initiative begun by former president George W. Bush to stop the ravages of AIDS in Africa has saved more than one million lives, according to a new report. The study tracked AIDS deaths and HIV infections in 12 African countries getting aid under the President’s Emergency Plan for AIDS Relief, or PEPFAR, during the four years after it was launched in 2003 as a five-year, $15 billion effort…. “It has averted deaths — a lot of deaths — with about a 10 percent reduction compared with neighboring African countries” [Reuters], said study coauthor Eran Bendavid. That reduction translates to about 1.1 million lives saved.
However, the study also found that the initiative had no effect on the prevalence of the disease, suggesting that it has been more effective at keeping infected people alive than in preventing new infections. Critics of the program said it didn’t put enough money toward prevention of HIV/AIDS. About a fifth of the funds were dedicated to prevention, and a third of that had to be used for abstinence-only programs. Congress reauthorized the program last year, removing the abstinence-only stipulation and increasing funding to $48 billion [San Jose Mercury News].
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The fish living in rivers around American cities are being medicated, like it or not. A broad new study of fish in five metropolitan areas has shown that fish are contaminated with a cocktail of prescription medications, including pharmaceuticals used to treat depression, bipolar disorder, allergies, high cholesterol, and high blood pressure. Researchers say this new form of pollution, a consequence of our medicated society, may have environmental or health consequences that aren’t yet understood.
Pharmaceuticals end up in drinking water—and in fish—when people take medications and residue passes through their bodies into the sewers. Conventional sewage and drinking water treatment filters out some substances, or at least reduces the concentrations [Chicago Tribune]. But pharmaceutical traces make it through the sewage processing and end up in river water. When fish take in the water through their gills, the chemicals accumulate in their livers and other tissue.
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Modafinil, a drug officially approved to treat narcolepsy but increasingly used off-label to improve cognitive performance, has been shown to carry a greater risk of addiction than was previously thought.
Brain scans of 10 healthy men taking Provigil, the version of modafinil made by the pharmaceutical company Cephalon, showed increased levels of dopamine in the part of the brain involved in pleasure and addiction. Dopamine is a neurotransmitter, a chemical that carries messages from nerve cell to nerve cell or other tissues. Drugs that increase dopamine have the potential for abuse [USA Today]. The demonstrated effect is similar to that known to accompany classically addictive stimulants, and federal health officials hope that the findings will serve as a warning that modafinil may have unexpected and tragic consequences for people who use it simply for a brain boost [LA Times].
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