A group of researchers have erased memories in rats, profoundly altering the animals' reaction to past events. Then they put them back.

The study is the first to show the ability to selectively remove a memory and predictably reactivate it by stimulating nerves in the brain at frequencies that are known to weaken and strengthen the connections between nerve cells - synapses.

The scientists optically stimulated a group of nerves in a rat's brain that had been genetically modified to make them sensitive to light, and simultaneously delivered an electrical shock to the animal's foot. The rats soon learned to associate the optical nerve stimulation with pain and displayed fear behaviors when these nerves were stimulated.

New research reveals that bilingualism has a positive effect on cognition later in life. Findings published in Annals of Neurology, a journal of the American Neurological Association and Child Neurology Society, show that individuals who speak two or more languages, even those who acquired the second language in adulthood, may slow down cognitive decline from aging.

Like blonde hair? You can thank the Kit ligand gene.

A single-letter change in the genetic code is enough to generate blond hair in humans, according to a new analysis by Howard Hughes Medical Institute scientists which has pinpointed that change, common in the genomes of Northern Europeans.

A handful of genes likely determine hair color in humans and the precise molecular basis of the trait remains poorly understood, and discovery of the genetic hair-color switch didn't begin with a deep curiosity about golden locks. It began with fish.

Twenty years after the hormone leptin was found to regulate metabolism, appetite, and weight through brain cells called neurons, a new study in Nature Neuroscience says that the hormone also acts on other types of cells to control appetite.

Leptin, a naturally occurring hormone, is known for its hunger-blocking effect on the hypothalamus, a region in the brain. Food intake is influenced by signals that travel from the body to the brain. Leptin is one of the molecules that signal the brain to modulate food intake. It is produced in fat cells and informs the brain of the metabolic state. If animals are missing leptin, or the leptin receptor, they eat too much and become severely obese.

A UCLA research team has discovered a new hormone called erythroferrone, which regulates the iron supply needed for red blood-cell production.

Iron is an essential functional component of hemoglobin, the molecule that transports oxygen throughout the body. Using a mouse model, researchers found that erythroferrone is made by red blood-cell progenitors in the bone marrow in order to match iron supply with the demands of red blood-cell production. Erythroferrone is greatly increased when red blood-cell production is stimulated, such as after bleeding or in response to anemia.

Researchers have defined a previously unrecognized genetic cause for two types of birth defects found in newborn boys 

"Cryptorchidism and hypospadias are among the most common birth defects but the causes are usually unknown," said Dr. Dolores Lamb, director of the Center for Reproductive Medicine at Baylor and lead author of the report in Nature Medicine. 

Cryptorchidism is characterized by the failure of descent of one or both testes into the scrotum during fetal development. In the adult man, the testes produce sperm and the male hormone, testosterone. Hypospadias is the abnormal placement of the opening of the urethra on the penis. Both birth defects are usually surgically repaired during infancy.

At the 50th Annual Meeting of the American Society for Clinical Oncology (ASCO), University of Colorado Cancer Center researchers reported results of a Phase I trial of OMP-54F28 (FZD8-Fc), an investigational drug candidate discovered by OncoMed Pharmaceuticals targeting cancer stem cells (CSCs). The drug was generally well tolerated, and several of the 26 patients with advanced solid tumors experienced stable disease for greater than six months. Three trials are now open for OMP-54F28 (FZD8-Fc) in combinations with standard therapy for pancreatic, ovarian and liver cancers, being offered at the CU Cancer Center and elsewhere.

If you want to survive your hospital stay, try to avoid being admitted on the weekend. 

A systematic review and meta-analysis
of various world regions that included 72 studies and 55,053,719 participants found that weekend admission was associated with increased morality of between 15% and 17% depending on the statistical technique used. 

It must be due to higher emergency status if it is the weekend, right? Some, but the authors say the quality of care is just poorer also, which is not going to make nurses and doctors who work weekends very happy.

In the debate over government control of health care in the United States, critics looked at the UK system and its death panels, which drew an arbitrary line on when to stop treatment. Their recent efforts led to such an outcry that the government has said they were ending the incorrectly named Liverpool Care Pathway and its policy of subtle euthanasia.

Most ethicists in the UK have been in favor of letting government rather than doctors determine patient care but an Emeritus Professor of medical ethics at Imperial College London talking at this year's Euroanaesthesia meeting titled will at least argue that a patient's age should not in itself be considered an ethically relevant criterion for deciding 'where to stop' treatment.

While western nations have dropped emissions on schedule, led by the United States, which has pushed its greenhouse gas emissions from energy back to early 1990s levels and coal back to early 1980s levels, the increasingly modern developing world have continued to produce more emissions, causing worldwide levels to rise.

There is no short cut. Emissions need to be reduced. So forget about positioning giant mirrors in space to reduce the amount of sunlight being trapped in the earth's atmosphere or seeding clouds to reduce the amount of light entering earth's atmosphere - if we can't figure out why emissions have risen but temperatures have not, tinkering with clouds is a very bad idea.