Hormonal treatments administered as part of the procedures for sex reassignment have well-known and well-documented effects on the secondary sexual characteristics of the adult body, shifting a recipient's physical appearance to that of the opposite sex.

New research published in the current issue of Biological Psychiatry indicates that these hormonal treatments also alter brain chemistry.

Researchers at the Medical University of Vienna, led by senior authors Dr. Siegfried Kasper and Dr. Rupert Lanzenberger, show that administration of the male hormone testosterone in female-to-male transsexuals raises brain levels of SERT, the protein that transports the chemical messenger serotonin into nerve cells.

A deadline passed on Oct. 3 for countries in the EU to opt out of future "GMO Crop" planting approvals.

The naturally occurring bacteria on a frog's skin could be the most important tool for helping the animal fight off a deadly skin disease, according to an experiment conducted by Virginia Tech researchers.

Antibiotics to get rid of the normal bacteria don't significantly alter the rate of fungal infection, but they did cause the frogs to lose weight, suggesting that having their normal bacteria is important for frog health. In addition, treatment with probiotic bacteria did not decrease fungal infection as expected.

However, naturally occurring skin bacteria can respond to infection and adjust structure and function to compensate for it, according to the team.

A new global review led by the University of Exeter that set out to investigate the hazards of marine plastic pollution has warned that all seven species of marine turtles can ingest or become entangled in the discarded debris that currently litters the oceans.

The research, which was carried out in collaboration with Plymouth Marine Laboratory, North Carolina Wildlife Resources Commission, North Carolina State University, Duke University Marine Lab and James Cook University, is published in the ICES Journal of Marine Science and reveals serious knowledge gaps in the diverse and complex pathways in which plastic pollution can harm marine life.

What has previously been known as good cholesterol--high density lipoprotein (HDL)--has now been shown to be not so good in protecting women against atherosclerosis while they are transitioning through menopause, according to a new study from the University of Pittsburgh Graduate School of Public Health that was presented last week at the annual meeting of The North American Menopause Society (NAMS) in Las Vegas.

What's the best time to tweet, to ensure maximum audience engagement? Researchers at the University of Maryland have demonstrated that an algorithm that takes into account the past activity of each of your followers -- and makes predictions about future tweeting -- can lead to more "retweets" than other commonly used methods, such as posting at peak traffic times.

The internet is full of advice about when to tweet to gain maximum exposure, but the new study subjects marketing folk wisdom to scientific scrutiny.

A pioneering surgical technique has restored some hand and arm movement to patients immobilized by spinal cord injuries in the neck, reports a new study.

Like railroad switchmen, the focus is on rerouting passageways; however, instead of trains on a track, the surgeons redirect peripheral nerves in a quadriplegic's arms and hands by connecting healthy nerves to the injured nerves. Essentially, the new nerve network reintroduces conversation between the brain and the muscles that allows patients, once again, to accomplish tasks that foster independence, such as feeding themselves or writing with a pen.

Working with gut stem cells from humans and mice, scientists from have successfully grown healthy intestine atop a 3-D scaffold made of a substance used in surgical sutures. 

In a further step that takes their work well beyond proof of concept, researchers report their laboratory-created intestine successfully regenerated gut tissue in the colons of dogs with missing gut lining.

An international research team has shown that epidemics of dengue, which is caused by a mosquito-borne virus across southeast Asia, appear to be linked to the abnormally high temperatures brought by the El Niño weather phenomenon. 

Now, as the most intense El Niño in nearly two decades is emerging in the Pacific, the finding - reported in today's issue of the Proceedings of the National Academy of Sciences (PNAS) - may be a harbinger of a spike in cases of the dangerous hemorrhagic fever throughout southeast Asian countries early next year.

"Large dengue epidemics occur unexpectedly, which can overburden the health care systems," said lead author Willem G. van Panhuis, M.D., Ph.D., assistant professor of epidemiology at Pitt Public Health.