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| The Pill |
Antiretroviral drugs have turned the AIDS epidemic around, by thwarting the virus in HIV-positive patients. But new research suggests that this powerful treatment may have another benefit — as a weapon against infection in healthy individuals.
In a trial involving nearly 2,500 HIV-negative, but high risk, gay men in six countries, researchers found that a combination antiretroviral pill called Truvada reduced the risk of HIV infection by 44%, compared with placebo. When scientists looked more carefully at the study volunteers who took the medication most faithfully, on a daily basis, they found that the risk of contracting HIV was even lower — 73% lower than the placebo group.
More studies will need to confirm the benefit of antiretrovirals in the prevention of HIV, and public health experts warn that even if the results hold up, it would not replace the best method of prophylaxis: safe sex and consistent use of condoms. That's because the way so-called pre-exposure prophylaxis, or PrEP, works is to load up high-risk people with HIV-disabling antiretroviral drugs before exposure to the virus, which allows the medication to hit HIV as early as possible. But the drugs do not work as a vaccine would, by priming the immune system to actually prevent infection.
Synthetic Cell
Move over, Dr. Frankenstein, and make room for your 21st-century counterpart, Dr. Venter. That's J. Craig Venter, co-mapper of the human genome, who this year took another step toward creating life in the lab. Generated from a painstaking process of stitching together the chemicals that compose DNA, Venter synthesized the entire genome of a bacterium, which was inserted into a cell and was able to replicate. Granted, Venter's "synthetic cell" had hardly the personality of Mary Shelley's angst-fueled monster, but it's man-made life nonetheless. Venter hopes his findings will be the first of a long line of lab-made creatures in synthetic biology. By mixing and matching genetic material into viable combinations, Venter is already generating organisms that may serve as new types of biofuel, or even speed up flu vaccine production by allowing researchers to keep ready-made versions of different viral strains of influenza on lab shelves.
Blood Test for Alzheimer's
Despite the increasingly sophisticated methods clinicians have for diagnosing disease, Alzheimer's remains out of reach for even the most advanced imaging and molecular probes. The degenerative illness can be definitively diagnosed only at autopsy, when pathologists can confirm the presence of hallmark plaques and tangles in the brain. But a promising new blood test may help confirm a diagnosis early in the disease's progression, which opens the possibility for prevention of dementia and mental decline even before the earliest onset of symptoms. The new test analyzes more than two dozen proteins in the blood, and is 80% accurate in identifying patients with the disease. It is only the latest in a series of new methods, including tests of spinal fluid, aimed at detecting and confirming Alzheimer's earlier in patients' lives. Quicker diagnoses could help patients take advantage of behavioral interventions — such as keeping the mind active by maintaining social contacts and learning new things — that may slow the mental deterioration of Alzheimer's.
FDA Approves Botox for Migraines
Who knew that vanity could yield a new treatment for pain? After some patients who received Botox injections to prevent wrinkles in their forehead reported that their migraines also seemed to diminish, scientists — especially those at Allergan, the manufacturer of Botox — decided to investigate. Based on data from two large trials involving more than 1,000 patients, the company successfully convinced the Food and Drug Administration (FDA) that patients receiving Botox in the facial area experienced fewer days of migraine pain each month than those who did not get the muscle paralyzing injections. The FDA approval means that insurers may start covering the cost of Botox, which can cost thousands of dollars over several months, to treat migraines. It's still difficult to predict which headache patients will benefit the most, say experts, but at least migraine sufferers won't have to visit the plastic surgeon on the sly to relieve pain — or pay for treatments out of pocket.
Taking the Resuscitation Out of CPR
For 50 years, ever since cardiopulmonary resuscitation (CPR) was first described in 1960, rescuers have been saving lives the same way, by combining mouth-to-mouth resuscitation with chest compressions to revive unresponsive victims. But after new data showed that chest compressions alone were just as effective as traditional CPR in rescuing victims of cardiac arrest, the American Heart Association (AHA) decided to update the decades-old process. The new rules for CPR put more emphasis on the chest compressions, and in some cases do away with resuscitating breaths altogether.
In recent years, several studies have found that untrained bystanders are more comfortable performing chest compressions, without mouth-to-mouth — even with the help of a trained 911 operator — and that victims who receive only compressions are as likely to survive as those who receive full CPR. These results, coupled with the fact that only 30% of those in need of CPR actually get it — in large part because of untrained bystanders' reluctance to perform what they view as a complex procedure — forced the AHA to revise its CPR guidelines.
The new recommendations advise all rescuers, including trained emergency medical personnel, to reverse the current protocol for CPR and begin with 30 firm chest compressions, then turn to resuscitating breaths. The priority for those whose hearts may be in distress, say AHA experts, is to get the heart pumping again, and starting off with chest compressions may keep damage from a stopped heart to a minimum.
The FDA Restricts Avandia
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Eleven years after it hit the market and became a worldwide blockbuster, the diabetes medication Avandia (rosiglitazone) was slapped with the FDA's most stringent drug restrictions yet. Now, the medication that helps control blood sugar in patients with Type II diabetes can be prescribed only by physicians who are part of a registry certifying that they are aware of the increased risk of heart attack associated with the drug. These doctors may dispense Avandia only if their patients have exhausted all other treatment options, and patients must sign off on these risks as well.
The FDA's decision, according to some experts, was long overdue, considering that researchers first reported increased heart risks among Avandia users in 2007. At that time, the FDA instituted its first warning on the drug's label. And yet a government review of the drug's safety revealed that its manufacturer, GlaxoSmithKline, was aware of the heightened risks associated with its product not long after it hit the market in 1999.
The good news for patients who respond well to Avandia but are finding it difficult to keep their prescription filled under the new restrictions is that a similar drug, Actos (pioglitazone), does not seem to pose the same risks to the heart.
Blood Test for Heart Attack
A heart attack starts with blockages in the blood vessels, so where better to look for predictors of heart trouble than in the blood? At the moment, the most reliable way to check the status of the heart's vessels is by angiogram, an invasive procedure that involves snaking a thin tube into the vessels from an artery in the leg. But researchers have now identified a preliminary panel of 23 genes that code for blood proteins, which was 83% accurate in detecting blood-vessel obstructions typical of heart disease. When doctors added this blood test to existing measures of heart attack risk — including symptoms of chest pain and family history of health problems — it improved by 16% their ability to classify patients as being at high or low risk, compared with traditional methods alone. It's too much to expect that the blood test by itself can predict heart attack, at least for now, but it could serve as an early warning call for patients who register as high risk. Perhaps by prompting changes in diet and lifestyle habits in these patients, it can help prevent them from ever having a heart attack at all.
Predicting IVF Success
For couples choosing to start a family with in vitro fertilization (IVF), the odds are not always in their favor. The procedure, even under the best circumstances, has a 30% chance of resulting in a live birth on average. So it was welcome news indeed when Stanford University researchers reported on a new method for selecting the strongest embryos, which would most likely result in a pregnancy and live birth.
By filming the first few hours of an embryo's activity after fertilization, the scientists were able to come up with a profile of characteristics of embryos that were most likely to continue developing and survive for several days, instead of dying off. Among other things, the criteria included the time that the embryos took to make their first division from one cell into two, as well as the time that this division itself took to unfold. The next step will be to put this video-based assessment to the test in an IVF clinic, and determine whether the analysis can actually improve pregnancy and live birth rates.
Artificial Ovary
In more good news for those struggling with infertility, scientists reported success in creating an artificial ovary that could one day nurture immature human eggs outside the body. Researchers led by a team at Brown University managed to coax three primary ovary cells donated by patients into a 3-D structure resembling an ovary. In the lab, the cell types interacted with one another and functioned for all intents and purposes like a real ovary, even successfully maturing a human egg from its earliest stages in the follicle to a fully developed form.
Most immediately, the structure could help IVF technicians improve success rates. Currently when women donate eggs for a cycle of IVF, they provide a range of both mature and immature eggs; the less developed ones are less likely to be fertilized to become embryos. But by allowing technicians to mature these eggs in the lab, researchers might be able to help each IVF cycle become more efficient in leading to a pregnancy and eventual life birth. In addition, the artificial ovary could help women with ovarian disease, who are unable to produce mature eggs, take advantage of IVF to have children of their own.
Creating iPS Cells Safer and Faster
While the promise of a stem-cell treatment to treat disease remains far off, scientists continue to take giant steps toward bringing that potential from the lab to the clinic. Working with the groundbreaking type of stem cell known as induced pluripotent stem (iPS) cells — which can be generated from a skin cell, completely bypassing the need for embryos — researchers at Children's Hospital Boston have overcome a critical hurdle in making the technology safe for human patients. Until now, to create iPS cells from skin cells, researchers needed to expose the skin cells to both viruses and cancer-causing genes to reprogram them to an embryo-like state. Now the Boston scientists report success in using another form of the added genes, known as RNA, that eliminates the danger posed by the insertion of the viruses and cancer-promoting genes. And as an unexpected bonus, the technique is about 100 times more efficient in making iPS cells than the older method. The new findings mark a significant advance toward someday using stem cells as a source of new and healthy cells to replace those that have been destroyed by disease.
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