Researchers have tweaked HIV virus to create a strain that can infect monkeys, and say the development will allow better testing of vaccines and AIDS drugs. Until now, AIDS researchers used monkeys infected with simian immunodeficiency virus, or SIV. The virus is similar to ours, but it’s far from a perfect research tool…. Though SIV and HIV wreak similar havoc on their hosts’ immune systems, drugs affect them differently. While that makes SIV useful for studying how the disease progresses, it’s less useful for studying potential treatments [Wired News].
The new strain of HIV was developed by altering a single gene in the human version to allow it to infect a type of monkey called a pig-tailed macaque [Reuters]. The researchers replaced one HIV gene with the SIV version of the gene, which blocks virus-killing proteins made by the monkey and allows the infection to take hold. Even this altered virus doesn’t make the monkeys very sick, but while animal lovers may see that as a benefit, researchers see it as the final hurdle to overcome.
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The gas that creates the foul odor in rotten eggs, hydrogen sulfide, may hold the key to the next blockbuster drug to treat erectile dysfunction, according to a new study. Researchers studied penile tissue discarded by men having male-to-female sex-change operations and found that the tissue expresses hydrogen sulfide; researchers say the gas promotes erections by relaxing the tissue around blood vessels, allowing more blood to flow into the penis. Researchers say the findings raise the possibility of developing an alternative to Viagra by creating a drug that boosts production of the gas.
Viagra works by stimulating the production of nitric oxide, which usually relaxes the penile tissue. The physical result of the hydrogen sulfide treatment appears to be the same — relaxing the smooth-muscle in the penile tissue known as the corpus cavernosum, but it exploits a different chain of molecular tools. “This is a completely different pathway…. If it were to work out in humans, it would be a way to help out people that aren’t responding to Viagra and drugs like it” [Wired News], says urologist Jim Cummings, who was not involved in the new research.
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A simple urine test is being developed that would revolutionize the treatment of prostate cancer by differentiating between the benign and aggressive forms of the disease.
While prostate cancer is one of the most commonly diagnosed cancers in men, the real challenge for treatment tends to lie in measuring the progress of the disease. A person can live a long time with benign prostate cancer, but the aggressive kind of tumor grows much more quickly and requires urgent treatment. The current method for distinguishing between the two can involve several rounds of testing, including an invasive and painful biopsy.
The urine test, which will not be ready for at least another three to five years, would be an easy and inexpensive way to determine which type of cancer is present, researchers report in Nature [subscription required]. Research for the test began when doctors found that men with an aggressive form of prostate cancer carry elevated levels of a particular molecule in their urine [The Guardian].
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The first clinical trial of a therapy based on human embryonic stem cells has received the green light from the FDA, marking a scientific and political milestone for embryonic stem (ES) cell research. The biotech company, Geron Corporation, received approval today for a study that would inject neural stem cells into patients suffering from spinal cord injuries. The study will be mainly a test for safety, but functional improvements, which have been observed in animals trials, may be possible. “For us, it marks the dawn of a new era in medical therapeutics. This approach is one that reaches beyond pills and scalpels to achieve a new level of healing,” Geron Chief Executive Dr. Thomas Okarma said [Reuters].
ES cells are taken from embryos a few days after fertilization and have the potential to differentiate into any type of cell in the body. The undifferentiated cells can’t be used directly, because they can form cancers called teratomas. But they can be used in the lab to generate potentially inexhaustible supplies of all other types of cell[s] that might be needed for repair. The type to be used in the trial are neural stem cells called oligodendrocyte progenitor cells. These support other neurons in the brain and nerves by supplying growth factors and by producing the myelin sheaths that protect neurons from damage [New Scientist]. The FDA will allow Geron to implant these neural stem cells directly into the spinal cords of eight to ten paraplegics. The trials are expected to begin this summer, and may be carried out in multiple medical centers. The patients have not yet been recruited because the injections must take place within two weeks of the spinal cord injury, before scar tissue forms.
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A certain herd of 200 goats on a Massachusetts farm may look bucolic and quaint, but they actually comprise a living, breathing pharmaceutical factory, or “pharm.” The goats have been genetically engineered t0 produce a blood-thinning drug in their milk, and a report from the FDA has just declared that the drug is effective and safe for human use. An FDA advisory panel will make a recommendation this Friday on whether to approve the drug for sales; if the drug is approved, it would be the first application under new FDA regulations that allow animals to be genetically altered to produce drugs, model human disease, produce industrial or consumer products or improve their use as food [USA Today].
The goats, which are being bred by the biotech company GTC Biotherapeutics, produce a protein called antithrombin that prevents blood clotting. About 1 in 5,000 people don’t produce enough of the protein, putting them at risk of developing blood clots in their veins. Such clots can be extremely painful. If they break loose and travel through the bloodstream to the lungs or the brain, the consequences can be catastrophic. Pregnant women with the disorder are at high risk of miscarriage or stillbirth, because of blood clots in the placenta [AP]. While people with the deficiency typically manage their condition with conventional blood thinning drugs, such drugs aren’t suitable for surgeries and childbirth, when the risks of blood clots are particularly high–that’s where the new drug would come in. GTC is also developing further studies to test the drug in patients at risk for clots in non-hereditary conditions such as coronary bypass surgery [Reuters].
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Naturally lush lashes can be yours within 16 weeks, claims the drug company Allergan, which has received approval from the Food and Drug Administration (FDA) for Latisse, the first ever eyelash-enhancing medication. According to the company, clinical trials show that daily dabs of Latisse on the edges of eyelids produce longer, thicker lashes, although mild side effects are possible. Allergan plans to start selling prescription-only Latisse by the end of March.
The eyelash-enhancing ingredient in Latisse is bimatoprost, a compound derived from fatty acids that bind to receptors in the eyelashes that may be involved in the development and re-growth of hair follicles. Allergan has used bimatoprost since 2001 in Lumigan, an Rx eye drop that lowers eye pressure in people with glaucoma [Scientific American]. Drugmakers stumbled upon the idea for Latisse when doctors and patients noticed lusher lashes on glaucoma patients taking Lumigan. Soon after, some doctors began writing Lumigan prescriptions for cosmetic patients, and competitors raced to create eyelash products that used bimatoprost or similar ingredients [The Wall Street Journal, subscription required]. Allergan, which also produces Botox, has since sued 11 companies for patent infringement for using bimatopost to promote lash growth.
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An experimental drug has shown promise in preventing emphysema in mice exposed to cigarette smoke, giving researchers new hope that they’ll soon find a way to combat one of the most stubborn, untreatable, and common killers of humans. Even though the study focuses on emphysema in mice, the researchers suggest the drug could work in people by delaying or preventing chronic obstructive pulmonary disease, which encompasses emphysema and chronic bronchitis and is the fourth most common cause of death in the United States [Science News].
The drug, called CDDO-imidazole, or CDDO-Im, works by activating a gene called Nrf2, explains study coauthor Shyam Biswal. In prior research, Biswal and colleagues found that Nrf2 works as a “master gene,” turning on genes involved in protecting the lungs from pollution and cigarette smoke. “The Nrf2 pathway is the major antioxidant and detoxifying response in the lungs. Therapies targeting this pathway need to be developed and tested in patients,” said Biswal [Reuters].
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Pharmaceutical giant Wyeth is under scrutiny for its practice of paying ghostwriters to draft scientific journal articles favorable to its products and publishing them under the names of academic researchers. Some of the ghostwritten reports involve Wyeth’s hormone replacement therapy, Prempo, and deny the results of a federal study that linked the drug to an increased risk for breast cancer. The inquiries come as part of the Senate Finance Committee’s examination of “medical ghostwriting,” part of a broader probe into the influence of drug companies on the health-care industry [Wall Street Journal].
The investigation is being spearheaded by Senator Charles E. Grassley of Iowa, who last week sent a letter to Wyeth’s chairman requesting documentation of the company’s ghostwriting and publishing procedures. The letter [pdf] said Wyeth’s publications resembled “subtle advertisements rather than publications of independent research” and that “any attempt to manipulate the scientific literature, that can in turn mislead doctors to prescribe drugs that may not work and/or cause harm to their patients, is very troubling.” In response, a Wyeth spokesman accused Mr. Grassley of recycling old arguments and insisted that “The authors of the articles in question, none of whom were paid, exercised substantive editorial control over the content of the articles and had the final say, in all respects, over the content” [New York Times].
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If you could take a pill to boost your concentration and mental stamina, would you do it? Around the country, thousands of college students are already answering “yes” to that question and are using prescription medications like Ritalin as study aids, and researchers say the demand for such “smart pills” is likely to grow. Now, in a new essay, a group of neuroscientists and bioethicists is arguing that society shouldn’t frown on such practices; instead the authors assert that “we should welcome new methods of improving our brain function,” and that doing it with pills is no more morally objectionable than eating right or getting a good night’s sleep [Chronicle of Higher Education].
Stimulants like Ritalin and Adderall are prescribed for attention deficit hyperactivity disorder and are commonly used by people without a prescription to help them focus their attention, while a narcolepsy drug called Provigil is sometimes used by people trying to keep their brains alert and awake. The new essay cited a recent survey that found nearly 7 percent of students in U.S. universities have used prescription stimulants, and on some campuses, as many as a quarter of students have used the drugs for non-therapeutic purposes. “It’s a felony, but it’s being done,” [coauthor Martha] Farah said [Reuters].
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A promising target for next-generation cancer therapies might not be a target after all, according to a new study in Nature [subscription required]. The work calls into question the “cancer stem cell theory,” which claims that a rare class of cells, cancer stem cells, are responsible for initiating and spreading cancer tumors. But by tweaking previous experimental procedures, researchers working with human melanoma cells in mice now report that cancer stem cells are much more prevalent that previously thought. “We’re not trying to claim there is no merit to the field, but we think that the frequency of cancer stem cells will be much higher,” said [co-author] Sean Morrison… . “And there will be some cancers like melanoma where lots of cells will be tumorigenic and it won’t be possible to treat those cancers by treating a small subset of cells” [Wired Science].
Cancer stem cells—so-called because they share genetic similarities with standard stem cells—were first identified in 1994 and since then have been reported in cancers of the brain, breast, colon, and pancreas. They provided a well-defined target for cancer drugs since they were thought to number only a few in a million. Like evil relatives of standard organ-forming stem cells, cancer stem cells build tumors. It’s an appealing idea because it provides a new, well defined target for treatment [Wired News]. However, not everyone in the field was smitten with the new theory.
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The official death toll from the cholera outbreak in Zimbabwe has climbed to nearly 500, according to the World Health Organization. But doctors on the ground say the actual fatalities may be closer to 1,000, with more than 12,000 infected since the start of the outbreak in August. Severe shortages of clean water, food, and medicine have allowed the normally treatable illness to ravage the country. Poorer areas have been without running water for months and just this week, the government cut off water to the nation’s capital, Harare. “The country is reaching a catastrophic level, in terms of food, health delivery, education,” said Morgan Tsvangirai, the MDC [opposition party] leader. “Everything seems to be collapsing around us” [Times Online].
Authorities say they have run out of water-purifying chemicals and have therefore shut down the water system in an attempt to contain the waterborne disease. But without running water, sanitation systems are nonexistent and sewage lies in the open air. “Proper hygiene is the best protection against cholera and you can’t do that without clean water,” [BBC News] said Marcus Bachmann of Doctors Without Borders. Residents have resorted to digging shallow wells and using contaminated water despite the government’s warning to use only boiled water. “We are afraid but there is no solution, most of the time the electricity is not available so we just use the water,” resident Naison Chakwicha said [USA Today]. The Health Minister has even asked residents to stop shaking hands. “Although it’s part of our tradition to shake hands, it’s high time people stopped,” he said [CNN].
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To mark World AIDS Day yesterday, researchers engaged in a “thought experiment” meant both to demonstrate the challenges and the possibilities confronting a world beset by the HIV virus. What would happen, they asked, if everyone was tested annually for HIV, and all people with positive results were immediately put on antiretroviral drugs? In a new study published in the journal The Lancet [subscription required], researchers predicted what the effects of such a policy would be in South Africa. They worked out that treating everyone with the virus with antiretroviral drugs would reduce incidence from 20 per 1000 people to just 1 per 1000 within 10 years…. That’s because the drugs keep levels of the virus in the blood down, making people less infectious – even if they have unsafe sex [New Scientist].
Currently, people have to seek out HIV tests, and those who don’t engage in high-risk behavior (like unsafe sex or intravenous drug use) often never get tested. In addition, the expensive antiretroviral drugs currently aren’t prescribed to HIV-positive patients until their immune systems are compromised and they begin to show symptoms of AIDS. The researchers argue in their article that present policies aren’t working, as 33 million people around the world are currently infected with HIV. The American College of Physicians also released new recommendations this week, advising doctors to routinely screen all patients if possible.
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Researchers may have uncovered one of the universal causes of aging: A crucial type of protein that serves a double duty in organisms ranging from yeast to mice, and that becomes overwhelmed as the organism ages. The protein is charged both with repairing DNA damage and with regulating gene expression (so that, for example, a gene necessary for liver function doesn’t suddenly get turned on in the brain), and a new study has shown that when the protein is busy repairing DNA, it can’t perform its other task. Says lead author David Sinclair: “One idea of why we age is that DNA becomes damaged or mutated…. But perhaps the main culprit is the effect of genes switching on and off, and that should be reversible” [Wired News].
About a decade ago, researchers identified a protein called Sir2 that zooms to the spot of broken DNA in yeast cells and repairs the breaks. But to do that, Sir2 has to abandon its job of inactivating a sterility gene elsewhere in the yeast genome. The result is yeast cells that have intact DNA but are sterile, a symptom of aging in the fungi…. “This may be a very fundamental Achilles’ heel of life,” says Sinclair [ScienceNOW Daily News]. Now, Sinclair’s team has identified the mammalian equivalent of that protein, called SIRT1, and have determined that it plays a similar role in aging mice: When it focuses on repairing DNA damage, it neglects its gene regulation duties.
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A hormone produced in the gut appears to limit bone formation, scientists report in Cell [subscription required]. The hormone, serotonin, is the same one produced by the brain to regulate mood, learning, and sleep, but the new study finds that serotonin produced by the gut has an entirely separate function. Mice engineered to produce extra serotonin formed weak bones, while mice engineered to produce less serotonin developed extra-strong bones. The research, though still basic, suggests new avenues of osteoporosis research in humans. “It’s what you’d call a landmark study,” Bjorn Olsen [a Harvard cell biologist who was not involved with the study] says. “It opens new doors” [Science News].
Although serotonin produced by the gut makes up 95 percent of the body’s serotonin, its function had not been well understood. The connection between serotonin and bone formation revealed itself through two types of rare human diseases, both involving the gene Lrp5. People with one mutation produced less Lrp5 protein, developing fragile bones and blindness, while people with another mutation produced extra Lrp5 protein, developing unusually dense bones and resistance to osteoporosis. However, when the authors of the new study looked into the gene further, they were surprised to find that it acted not in bone cells but in cells of the gut. “We, as bone [researchers], thought of the skeleton as functioning independent of everything else,” said [Cliff Rosen, a bone biologist]. This group “asked the question, ‘could there be other regulators outside the skeleton that are regulating bone?’ and found the answer to be ‘yes.’” [The Scientist].
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Unfavorable results of drug trials are often swept under the rug, according to a new review of FDA drug applications. Nearly a quarter of drug trial outcomes submitted to the FDA by pharmaceutical companies—most of them unfavorable—remained unpublished or only partially published after five years. Published results were often positively skewed from those originally reported to the FDA. “These new findings confirm our previous suspicions that this is happening on a much broader systemic level. It shows that information is unavailable to those who really need it the most — the clinicians and the researchers,” [Science News] says An-Wen Chan of the Mayo Clinic.
Drug companies are required to submit the results of all drug trials to the FDA as part of new drug applications. After approval, these results are supposed to be made public, usually in the form of scientific publications. However, the new review published in PLoS Medicine found disturbing omissions and bias on the road to publication. The new analysis examined 164 trials for 33 new drugs that were approved by the FDA from January of 2001 to December 2002. By June 2007, one quarter of the trials were either published only in a partial form — as an abstract, or part of a pooled publication — or were not published at all [Science News]. Of 43 negative outcomes reported to the FDA, only 20 were later published. Nine percent of all published outcomes were more positive than those originally reported to the FDA.
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