ALSO NOTED: Viagra helps children in study; Edwards Lifesciences halts heart valve investigation; and much more...

> A small study indicates that children with a rare and fatal lung disease were helped by Viagra. Researchers said that more work is needed to be done to investigate the effects of Viagra on pulmonary hypertension. Story

> Edwards Lifesciences halted its investigation of an experimental heart valve procedure after "more than one" of the 10 patients in the trials died and others had serious complications. Story

> Durham, North Carolina-based Trimeris has signed a co-development pact with ChemBridge Research Laboratories to develop new HIV drugs. Article

> Johnson & Johnson and Boston Scientific have taken their battle over stents to court. Article

> Medarex and Boehringer Ingelheim have inked an antibody development pact. Release

And Finally... US scientists have created new brain stem cells in the lab, pointing the way to a potentially unlimited supply of new cells. Story