Science Digest

New HIV Strain Found In Cameroon Woman

A new strain of the virus that causes AIDS has been discovered in a woman from the African nation of Cameroon.

It differs from the three known strains of human immunodeficiency virus and appears to be closely related to a form of simian virus recently discovered in wild gorillas, researchers report in Monday's edition of the journal Nature Medicine.

The finding "highlights the continuing need to watch closely for the emergence for new HIV variants, particularly in western central Africa," said the researchers, led by Jean-Christophe Plantier of the University of Rouen in France.

The three previously known HIV strains are related to the simian virus that occurs in chimpanzees.

The most likely explanation for the new find is gorilla-to-human transmission, Plantier's team said. But, they added, they cannot rule out the possibility that the new strain started in chimpanzees and moved into gorillas and then humans, or moved directly from chimpanzees to both gorillas and humans.

The woman currently shows no signs of AIDS and remains untreated, though she still carries the virus, the researchers said. How widespread this strain is remains to be determined. Researchers said it could be circulating unnoticed in Cameroon or elsewhere. The virus's rapid replication indicates that it is adapted to human cells, the researchers reported.

-- Associated Press

Heart Muscle Tissue Might Regenerate

When skin tissue cells are injured, they often are able to regenerate themselves and consequently heal damaged skin. A new study suggests that heart muscle tissue cells may have similar regenerative properties when promoted by a naturally occurring cell growth factor called neuregulin1 (NRG1). This discovery, if proven safe and effective in humans, could lead to new treatment options for heart disease and failure.

The study, published in the July 24 issue of the biweekly journal Cell, shows that NRG1 induces the division and regeneration of healthy heart muscle tissue cells when injected into the bloodstream of rats and mice that have had a heart attack. This led to improved post-heart attack function in the rodents, according to the study.

NRG1 is present in the human nervous system, breast tissue and heart, said Bernhard Kuhn, a pediatric cardiologist at Children's Hospital in Boston and a researcher in the study.

"Its receptor has been implied to control heart development before birth," he said.