Blogs / 80beats

Dosing menopausal women with testosterone may be the key to helping those with low libidos get back in the mood, according to a new study. Proctor & Gamble Pharmaceuticals has published the results of a new trial of their testosterone patch, called Intrinsa, and say the results are encouraging for frustrated older women seeking a “Viagra for women.” However, nagging safety concerns are likely to keep the drug off the market in the United States for some time to come (although the drug is already on sale in Europe): During the new study, four of the test subjects using the patch developed breast cancer.

The 52-week study included 814 women with sexual desire disorder, characterized by troublesome low sexual desire or function…. The women were asked to keep sexual encounter diaries, and researchers used other established measures to assess sexual response during the six-month evaluation phase of the study. They found that compared to placebo users, the women who used the 300 microgram patch reported significant improvements in sexual functioning, including desire, arousal, orgasm, and pleasure [WebMD].

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Male-to-female transsexuals are more likely to have a genetic variant that may cause weaker testosterone signals in the brain during early development, according to a new study. Researchers say the finding is another piece of evidence that there is a genetic component to these men’s strong feelings that they’re really women who were born into the wrong body, a theory many experts have long endorsed based on anecdotal evidence. “People who come to our clinic describe how they knew they were different at a very early age, just three or four years old. This is something that people are born with,” Dr [Trudy] Kennedy said [Sydney Morning Herald].

The findings are important, but lead researcher Vincent Harley admits he hasn’t discovered a clear, single cause of transsexualism. While the genetic link was statistically significant, it was weak – 55% of the transsexuals had the [genetic variant], compared with 50% of normal men. Harley agrees that many more genes related to male-to-female transsexualism probably remain to be discovered [New Scientist].

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Teenage boys with behavior problems may be able to blame their brain chemistry, according to a new study. Psychologists studied boys with a history of antisocial behavior and measured their levels of the hormone cortisol, which usually surges during stressful situations, causing people to focus and behave more cautiously. They found that the troubled boys didn’t have the normal cortisol spike when they were put under stress, suggesting that they weren’t getting a chemical signal to regulate their emotions and actions.

Researchers say the findings suggest that some bad behavior should be considered a form of mental illness. “Most research has looked at social factors like peer groups, family life and socioeconomic factors,” said [lead researcher] Graeme Fairchild…. “These findings basically indicate that antisocial behavior is probably more biologically based than many people recognize and is similar to conditions like depression and anxiety” [Reuters].

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In a finding that has particular relevance right now, as the American public looks for scapegoats for the current financial crisis, a new study has found that men with higher levels of testosterone are inclined to make riskier financial decisions. Just how much riskier? Those with 33 percent more testosterone than average men invested 10 percent more of their dough. The findings are based on saliva samples from 98 male Harvard students taken before they played an investment game with $250 in real money [Scientific American].

Researchers say they didn’t outright prove that it was Wall Street men’s hormones that got us into this mess, but that the evidence is strongly suggestive. “Although our findings do not address causality, we believe that testosterone may influence how individuals make risky financial decisions,” said researcher Coren Apicella…. A recent study also showed that stock market traders made more money on days when their testosterone levels were highest [LiveScience].

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Researchers have found a gene in men that’s linked to happy marriages, according to a new study. The gene determines how the brain responds to a hormone that has previously been shown to cause monogamous behavior in prairie voles; researchers found that men with a certain variant of the gene were less likely to be married to their partners, and if they were married, they were more likely to have had a marital crisis and to have discussed the possibility of divorce.

In the study, researchers studied the genetics of more than 550 men who were in relationships, and then asked both the men and their partners a series of questions. Men with a variant of the gene tended to score badly on a questionnaire designed to assess how well they bond with their partner and were more likely to report having suffered marital difficulties…. The wives of those who were married were also less satisfied with their marriage than women whose husbands did not have that genetic variant [Telegraph].

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A study of an experimental prostate cancer drug showed dramatic results that have thrilled researchers: The drug shrank prostate tumors and doubled survival rates in more than 70 percent of patients with an aggressive form of prostate cancer. The test subjects were men whose cancer had not responded to other treatments, and who had a life expectancy of about a year.

Although the study, which was published in the Journal of Clinical Oncology [subscription required], covered only 21 patients, the drug is now being tested in more than 250 men with what appears to be similar results, experts said. “There is a general sense in the prostate cancer community that this agent is extremely promising and is very likely to have an important role in the management of prostate cancer patients,” said Dr. Howard M. Sandler [Los Angeles Times]. Experts say the drug could reach the doctors’ offices by 2011.

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Despite the International Olympic Committee’s vow to vigilantly test for performance enhancing drugs at the Summer Olympics in Beijing, some scientists and sports doctors say that athletes are likely to cheat at the games, and get away with it.

The focus is on erythropoietin (EPO), a hormone naturally produced by the kidneys which regulates red blood cell production. When extra EPO is injected before a competition, it boosts performance by increasing the amount of red blood cells in an athlete’s body; those blood cells then carry more oxygen to the hard-working muscles.

Anti-doping agencies regularly test athletes for EPO, but some researchers say the agencies can’t develop tests fast enough to keep up with new “copycat” versions of EPO, often produced by pharmaceutical companies in India, Cuba, and China. These cheap versions of EPO, often called biosimilars, can be easily bought over the internet…. Some scientists who track and monitor the development of copycat EPO drugs say there could be up to 80 different versions now being manufactured in different parts of the world [BBC News].

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A hormone therapy sometimes called “medical castration” that’s used to treat prostate cancer is of no help to patients in the early stages of the disease, according to a new study. What’s more, the treatment’s side effects far outweigh any potential benefit for most patients [Los Angeles Times].

The treatment, which cuts off the production of male hormones, has been found to be effective in treating aggressive prostate cancer that is spreading through the body; this prompted doctors to begin prescribing the hormone therapy to patients with early stage, localized tumors as well. But the results of this new study are likely to reverse that trend. Hormone therapy’s most obvious side effect is sexual dysfunction. Of greater concern are several recent studies linking [these] therapies to diabetes, heart disease, bone fractures, and reduced muscle mass [WebMD].

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The debate over the roots of homosexuality is possibly the most contentious manifestation of the “nature versus nurture” argument; gay rights advocates, gay rights opponents, and scientists have all joined the fray, advancing and criticizing different theories. With a new brain imaging study, the “nature” proponents seem to have gained a point in their favor.

Swedish researchers did MRI scans of 50 heterosexual men and women and 40 homosexual men and women and found surprising parallels. The brains of lesbians and straight men were anatomically symmetrical while the brains of gay men and straight women had a larger right brain hemisphere.

The researchers also looked at the amygdala, a part of the brain that’s associated with emotions, and found that straight women and gay men both have more connections between the amygdala and brain regions associated with anxiety and mood disorders. Meanwhile, the amygdala of lesbians and straight men had more connections to the region that controls fight or flight reactions.

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