THURSDAY, Jan. 24 (HealthDay News) -- A new malaria vaccine looked strong in a small trial conducted in Mali by a team of international researchers.

The vaccine -- designed to prevent the malaria parasite from entering blood cells -- was safe and provoked strong immune responses (up to a sixfold increase in vaccine-specific antibodies) in the 40 adults who received it, according to the 17-member research team, based at the Malaria Research and Training Center at the University of Bamako.

The volunteers were given three injections of full or half doses of the vaccine, with one month between each injection. The injections began in late December 2004, at the end of the malaria season in the rural town of Bandiagara in northeast Mali.

The study was published in the current issue of PLoS ONE.

This trial -- the first test of the vaccine in a malaria-endemic country -- was supported by the U.S. National Institute of Allergy and Infectious Diseases, which also helps fund the Malaria Research and Training Center. The team is now conducting a trial of the vaccine in 400 Malian children, aged 1 to 6.

Malaria is a leading cause of death in Africa and other developing countries. It kills more than 1 million people a year, most of them children.

More information

The U.S. Centers for Disease Control and Prevention has more about malaria.

WEDNESDAY, Jan. 23 (HealthDay News) -- Genetic variations that predict patient response to the two common antidepressant drugs citalopram (brand name Celexa) and venlafaxine (Effexor) have been identified by German researchers.

The team at the Max Planck Institute of Psychiatry in Munich found that 11 variants in the gene for a protective transporter protein called P-gp, which removes drugs and other substances from the brain, compromise the effectiveness of these two drugs.

In the first part of the study, the researchers knocked out genes for P-gp in mice and gave them antidepressants. They found that brain concentrations of citalopram and venlafaxine were regulated by P-gp, indicating that the antidepressants were "substrates" of the transporter protein.

Next, the team analyzed 443 people on antidepressants for genetic variants that correlated with reduced efficacy of the two antidepressants.

"To our knowledge, our results provide for the first time evidence that genetic variants in the (gene for P-gp) account for differences in the clinical efficacy of antidepressants, most likely by influencing their access to the brain," the researchers wrote.

The findings, published in the Jan. 24 issue of the journal Neuron, suggest that genetic testing could help predict how individual patients would react to specific antidepressants, the researchers said.

They added that genetic tests may also help predict the effectiveness of any drugs used to treat neurological diseases.

"The general conclusion to be drawn is that any drug treatment administered to treat CNS (central nervous system) diseases should be analyzed for its P-gp substrate status, which can be determined by using knockout mice. From a clinical point of view, the findings warrant that patients receiving a drug that is a P-gp substrate for the treatment of brain diseases are genotyped to exclude the possibility that a patient receives a drug that fails to enter the CNS to an extent required for efficacy," the study authors wrote.

Future development of antidepressants should take into account whether new drugs are transported by P-gp, and clinical trials of antidepressant drugs need to factor in the P-gp genetic status of participants, the researchers recommended.

More information

The U.S. National Institute of Mental Health has more about depression.

WEDNESDAY, Jan. 23 (HealthDay News) -- New research suggests that a specific part of the brain handles what might be called the "I've got it!" moments.

The research could lead scientists closer to more effective treatments for a variety of mental illnesses. Any new understanding of a brain region is helpful because it provides insight into "what's related to a physical problem versus a psychological issue," said Paul Sanberg, director of the University of South Florida College of Medicine's Center of Excellence for Aging and Brain Repair.

At issue is the brain's ability to learn that it's discovered the right approach to a challenge, such as picking the right answer on a multiple-choice test.

"In general, when one tries to solve a problem one has to be sure to recognize that the solution has been found and that it is no longer needed to pursue the search for an appropriate response," said study co-author Emmanuel Procyk, a researcher at the University of Lyon in France.

For example, he said, "when you face new software, you usually try menus and options with a specific goal in mind. By trying and making errors, you eliminate inappropriate selections, but once you find what you expected to produce, you detect and feel success, and consequently store this fruitful behavior for further use."

In the new study, Procyk and his colleagues placed two monkeys in front of computer touch screens and let them choose which target to press. The monkeys learned that some targets would give them a reward of juice.

As the monkeys took part in the experiment, researchers recorded electrical activity in the anterior cingulate cortex, a brain region connected to emotion, decision-making and the art of anticipating what will happen next.

The study findings are published in the Jan. 24 issue of the journal Neuron.

Judging from their analysis of the electrical patterns in the brain, the researchers suspect the region plays a role in both monitoring the situation and figuring out the best response to it.

"Neurons of that region react to the first meaningful reward, the one 'saying' that the goal has been reached and that there is no more need to explore," Procyk said.

Sanberg said: "If you have damage to that area, you're not going to react well to a reward. If you can't perceive the way the reward should be, you may [engage in] inappropriate behavior. Or you may not know you're getting the reward, or it may not be strong enough for you to adapt the behavior to the reward."

Drug addicts, for one, aren't able to properly handle their perception of rewards, Sanberg said.

The new research, which Sanberg called "elegant," could be useful in the future if scientists can figure out how to "alter" that part of the brain, perhaps through methods like deep-brain stimulation, he said.

Another study, published in the Jan. 23 online issue of PLoS ONE, also sheds light on the mechanisms behind the art of problem-solving.

Joydeep Bhattacharya, of Goldsmiths College in London, England, tracked brain rhythms while volunteers solved verbal problems. Often, the volunteers became mentally blocked when there was an excessive amount of gamma brain rhythm, which suggests that focusing too much on a particular problem might hinder the ability to arrive at a solution.

More information

Learn more about the brain from the U.S. National Institutes of Health.

TUESDAY, Jan. 22 (HealthDay News) -- The genomes of 1,000 people worldwide will be mapped in what scientists are calling the most detailed and medically relevant look at human genetic variation ever conducted.

As outlined by an international team of researchers on Tuesday, the 1000 Genomes Project will receive major support from the U.S. National Human Genome Research Institute (NHGRI), the Wellcome Trust Sanger Institute in England, and the Beijing Genomics Institute in China.

"The 1000 Genomes Project will examine the human genome at a level of detail that no one has done before," consortium co-chair Richard Durbin, of the Wellcome Trust Sanger Institute, said in a prepared statement.

Data from the project will be made available to the worldwide scientific community through public databases. The people who have their genomes sequenced will remain anonymous and will not have to provide any personal medical information.

Among the populations whose DNA will be sequenced in this effort are: Yoruba in Ibadan, Nigeria; Japanese in Tokyo; Chinese in Beijing; Utah residents with ancestry from northern and western Europe; Luhya in Webuye, Kenya; Maasai in Kinyawa, Kenya; Toscani in Italy; Gujarati Indians in Houston; Chinese in metropolitan Denver; people of Mexican ancestry in Los Angeles; and people of African ancestry in the southwestern United States.

"Such a project would have been unthinkable only two years ago. Today, thanks to amazing strides in sequencing technology, bioinformatics and population genomics, it is now within our grasp," Durbin said. "So we are moving forward to build a tool that will greatly expand and further accelerate efforts to find more of the genetic factors involved in human health and disease."

All humans are more than 99 percent genetically identical. However, understanding the small fraction of genetic variation among humans can help explain individual differences in disease susceptibility, response to drugs, or reaction to environmental factors.

Previous research has identified more than 100 regions of the human genome that contain genetic variants associated with the risk of common diseases such as diabetes, coronary artery disease, prostate and breast cancer, rheumatoid arthritis, inflammatory bowel disease, and age-related macular degeneration.

However, existing genome maps are not extremely detailed, which means that researchers often have to use expensive and time-consuming DNA sequencing to help them identify precise genetic variants that cause a disease.

The new genetic map created by the 1000 Genomes Project will help scientists more quickly pinpoint disease-related genetic variants and advance efforts to use genetic information to develop new ways to diagnose, treat and prevent genetic-related diseases.

"This new project will increase the sensitivity of disease discovery efforts across the genome five-fold and within gene regions at least 10-fold," NHGRI director Dr. Francis S. Collins said in a prepared statement.

"Our existing databases do a reasonably good job of cataloging variations found in at least 10 percent of a population. By harnessing the power of new sequencing technologies and novel computational methods, we hope to give biomedical researchers a genome-wide map of variation down to the 1 percent level. This will change the way we carry out studies of genetic disease," Collins said.

More information

Find out more at 1000 genomes  .