Scientists have discovered more about the intricacies of Natural Killer cells, a unique type of white blood cell important in early immune responses to tumors and viruses.  

Unlike most cells of the immune system that are activated by molecules found on the pathogen or tumor, Natural Killer cells are shut down by a group of proteins found on healthy cells. These de-activating proteins, known as Human Leukocyte Antigens or HLA molecules are absent in many tumors and cells infected with viruses, leaving them open to attack by the Natural Killer cells. 

Natural Killer cells recognize the HLA molecules using an inbuilt surveillance system called "Killer cell immunoglobulin-like receptors" (KIR).

Why do some people, chess players or musicians, practice less but attain more?

Rats exposed to the antidepressant citalopram, a serotonin-selective reuptake inhibitor (SSRI), just before and after birth showed substantial brain abnormalities and behaviors, according to a new study. The long-distance connections between the two hemispheres of the brain showed stunted growth and degeneration and the animals also became excessively fearful when faced with new situations and failed to play normally with peers – behaviors reminiscent of novelty avoidance and social impairments seen in autism.

The abnormalities were more pronounced in male than female rats, just as autism affects 3-4 times more boys than girls.

Does yoga help with chronic back pain?  Yes it does, but so does stretching.  Either is better than handing people a book, according to the largest U.S. randomized controlled trial of yoga to date. 

In the trial, 228 adults in six cities in western Washington state were randomly assigned to 12 weekly 75-minute classes of either yoga or stretching exercises or a comprehensive self-care book called "The Back Pain Helpbook". Nine in 10 of them were primary-care patients at Group Health Cooperative and participants in the trial typically had moderate, but not severe, back pain and relatively good mental health. Most had been at least somewhat active before the trial started. 

Teens who drink more than five cans fizzy soft drinks per week - less than one per day - are significantly more likely to commit violence or carry weapons, suggests research in Injury Prevention, part of the British Medical Journals.