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Tag: "sex" at biology news

Scientists discover way to block growth of prostate cancer cells

...t time a specific biochemical pathway by which the sex hormone, androgen, increases levels of harmful chemicals called reactive oxygen species (ROS) in the prostate gland that play a role in the development of prostate cancer. They found that a drug that blocks this pathway significantly prolonged survi...

New clues to how sex evolves

...e, giving rise to a unique new genome. But how did sex itself evolve" Researchers at the Department of En...his specialized cell division produces gametes, or sex cells, each of which has only one copy of each chromosome instead of the two copies most cells carry...

UCSF study will test new vaginal microbicide for herpes and HIV

...ore having intercourse. "If a woman has occasional sex it could be several times a month. If she were a sex worker it could be several times a day," she said. The study is being conducted in collaboration...

Monitoring poisons in the environment -- a woolly matter

...ep. Another significant observation related to the sex of the sheep ?values for wool concentration of both lead and copper were significantly higher in male sheep, which has been linked to the effect of androgens on metabolism. Dr Sneddon comments, "Sheep wool evidently has potential as a bio-indicato...

Syphilis rate on rise in US gay, bisexual men

...he rates dropped because fewer people were selling sex to get crack cocaine as the decade went by. How...hilis statistics do not identify the gender of the sex partners of infected people, the study authors infer that a large number of those infected ?62 perce...

Common parasitic infection leads to increased risk for HIV infection

... differences in the rates of condom use, number of sex partners, etc." said McClelland. The study pointed to several reasons why vaginal trichomoniasis could possibly lead to an increased risk of HIV acquisition. Trichomoniasis can cause tiny areas of bleeding within mucous membranes that could provi...

Fruit fly gene research may shed light on human disease processes

... or absence of the human Y chromosome that directs sex development, human females still need to determine...ntified the genes involved in counting Drosophilia sex chromosomes. Now, he and Avila have made another breakthrough, identifying a signaling pathway outs...

The influence of the menstrual cycle on the female brain

...vity.) Estrogens and progesterone are not just sex hormones that influence ovulation and reproduction; they also affect a large number of cognitive and affective functions. These two observations show that gonadal neurosteroids6 modulate the female dopaminergic system, but the question remains as ...

1/3 of sexually active older adults with HIV/AIDs has unprotected sex

...not sexually active, those who do have unprotected sex account for just 13 percent of the overall number of infected people who are aged 50 or older. However, one-third of those who are sexually active have unprotected sex, which suggests that prevention efforts may need to be more highly targeted towar...

Morphine makes lasting -- and surprising -- change in the brain

...ces survival-boosting behaviors such as eating and sex ?a reward system linked to addiction. The affected synapses, Kauer found, were those between inhibitory neurons and dopamine neurons. In a healthy brain, inhibitory cells would limit the release of dopamine, the "pleasure chemical" that gets released...

Salamanders suffer delayed effects of common herbicide

... and female organs by altering their production of sex hormones. Findings from Rohr's study, which was funded by the U.S Environmental Protection Agency, National Science Foundation, and the Kentucky Academy of Sciences, could have implications for global amphibian declines. "Salamanders, and amph...

Mitochondrial genes move to the nucleus -- but it's not for the sex

...onferred by sexual recombination. "The benefits of sex could have driven the transfer," he said. "There are powerful arguments out there for that. But that's just not what we saw." Brandvain, fellow graduate student Michael Barker, and their advisor, IUB evolutionary biologist Michael J. Wade, examin...

Bird sex is something else

...difference is genetic. Species with differentiated sex chromosomes (X and Y in humans, for example) get a... males and females get different-sized portions of sex chromosome genes with a balancing act geneticists call dosage compensation. But research published ...

No sex for 40 million years? No problem

A group of organisms that has never had sex in over 40 million years of existence has neverthe...ed today. The study challenges the assumption that sex is necessary for organisms to diversify and provides scientists with new insight into why species ev...

Penn researchers replace organ in adult mice using 'single-parent' stem cells

...rapeutic route for both genders; members of either sex can use this technique to produce compatible stem cells, much like you might donate blood for your own use in advance of an operation." Parthenogenesis, the act of creating an embryo without fertilization, is common in some plants, insects and ani...

New research says winning a Nobel Prize adds nearly 2 years to your lifespan

...etails (birth and death dates). They looked at one sex only to avoid differences in life span between sexes. They dropped four from that total who died prematurely for non biological reasons - such as active combat in the First World War. That left 524 scientists, of whom 135 actually won a Nobel Prize. ...

Surgeons develop simpler way to cure atrial fibrillation

...ue because the surgeons carefully matched the age, sex and cardiac conditions of a group of patients who underwent Cox-maze III in the past with patients undergoing Cox-maze IV. "This is the first documentation of the effectiveness of the ablation devices compared to the incisions of the Cox-maze III," D...

New recommendations against a major opportunistic infection -- cryptococcosis

...with more severe infections, such as the patient’s sex and the infecting serotype. In light of the result... severe in men than women, suggesting influence of sex hormones. It is also more severe in HIV+ than in HIV- individuals. In terms of mortality, it is thos...

Researchers find gene mutation that causes infertility in male mice

...oduces sperm and egg cells for reproduction. These sex cells contain only one set of chromosomes that combine during conception and create an embryonic cell with two chromosome sets, one from each parent. The mutation leads to a change in an amino acid in Dmc1 that blocks meiosis in its tracks, prevent...

Bisexual fruit flies show new role for neurochemical

Fruit flies' ability to discern one sex from another may depend on the number of receptors on the surface of nerve cells, and the number of receptors is controlled by levels of a ubiquitous brain chemical, University of Illinois at Chicago researchers have found. Everything from the abili...

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