Scientists have refuted a longstanding theory of how HIV slowly depletes the body’s capacity to fight infection, in new research published today.

The researchers were looking at T helper cells, a class of white blood cells which recognise infection and co-ordinate the body’s immune defences. They are attacked by HIV, and their numbers gradually decline in HIV positive patients. It has long been a major puzzle why this process of depletion is so slow, often taking 10 years or more.

Wild relatives of plants such as the potato and the peanut are at risk of extinction, threatening a valuable source of genes that are necessary to boost the ability of cultivated crops to resist pests and tolerate drought, according to a new study released today by scientists of the Consultative Group on International Agricultural Research (CGIAR). The culprit is climate change, the researchers said.

It's a scenario straight out of Gray's Anatomy – a paramedic or doctor plops a mask over the face of a person struggling to breathe and begins dispensing pure oxygen.

Yet growing research suggests that inhaling straight oxygen can actually harm the brain. For the first time, a new UCLA brain-imaging study reveals why. The findings fly in the face of national guidelines for medical practice and recommend a new approach adding carbon dioxide to the gas mix to preserve brain function in patients.

Applying topical retinol to the skin appears to improve the wrinkles associated with natural aging and may help to promote the production of skin-building compounds, according to a report in the May issue of Archives of Dermatology.

The wrinkles and brown spots associated with aging appear first and most prominently on skin exposed to the sun, according to background information in the article.

The use of peginterferon alone, or in combination with ribavirin, points to a cure for hepatitis C, the leading cause of cirrhosis, liver cancer and the need for liver transplant, a Virginia Commonwealth University researcher said today.

Mitchell Shiffman, M.D., professor in the VCU School of Medicine, and chief of hepatology and medical director of the Liver Transplant Program at the Virginia Commonwealth University Medical Center, is one of the lead investigators in the study, which was presented at the 38th annual Digestive Disease Week conference in Washington, D.C. VCU was among about 40 sites worldwide studying pegylated interferon alfa-2a, manufactured by Roche Inc.

Researchers at Boston University School of Medicine (BUSM) and McLean Hospital have found that practicing yoga may elevate brain gamma-aminobutyric (GABA) levels, the brain's primary inhibitory neurotransmitter. The findings suggest that the practice of yoga be explored as a possible treatment for depression and anxiety, disorders associated with low GABA levels.

The World Health Organization reports that mental illness makes up to fifteen percent of disease in the world. Depression and anxiety disorders both contribute to this burden and are associated with low GABA levels. Currently, these disorders have been successfully treated with pharmaceutical agents designed to increase GABA levels.