ASSOCIATED PRESS

STOCKHOLM, Sweden — Australian researchers Barry Marshall and J. Robin Warren won the 2005 Nobel Prize in physiology or medicine on Monday for their work on how the bacterium helicobacter pylori plays a role in gastritis and peptic ulcer disease, the Swedish Nobel Assembly said today.
Two Canadian stem cell researchers and British pioneers in determining how DNA is constructed were among the favourites for the coveted award honouring achievements in medical research.
It opens this year's series of prize announcements, and will be followed by physics, chemistry, literature, peace and economics.
"Warren, a pathologist from Perth, Australia, observed small curved bacteria colonizing the lower part of the stomach in about 50 per cent of patients from which biopsies had been taken," the Nobel Assembly said.
"He made the crucial observation that signs of inflammation were always present in the gastric mucosa close to where the bacteria were seen."
Marshall became interested in Warren's findings and together they initiated a study of biopsies from 100 patients.
"After several attempts, Marshall succeeded in cultivating a hitherto unknown bacterial species — later denoted Helicobacter pylori — from several of these biopsies," the assembly said.
"Together they found that the organism was present in almost all patients with gastric inflammation, duodenal ulcer or gastric ulcer. Based on these results, they proposed that Helicobacter pylori is involved in the aetiology of these diseases."
The medicine prize is awarded by the Karolinska institute in Stockholm as stated in the will of Alfred Nobel, a Swedish industrialist who founded the prestigious awards in 1895.
The process for selecting winners is extremely secretive — nominations are kept sealed for 50 years — leaving Nobel-watchers little to go on in their speculation.
However, one hint for possible winners is the annual Albert and Mary Lasker Foundation awards. Sixty-eight scientists who have won the $50,000 (U.S.) prizes have gone on to win Nobel Prizes in physiology or medicine.
This year's prize for basic medical research was shared by Ernest McCulloch and James Till of the Ontario Cancer Institute and the University of Toronto for their pioneering identification of a stem cell.
The Lasker prize for clinical medical research was shared by two British scientists, Sir Alec Jeffreys of the University of Leicester and Sir Edwin Southern of Oxford University, for DNA research.
The medicine prize includes a check for 10 million kronor (about $1.3 million (U.S.)), a diploma, gold medal and a handshake with the king of Sweden at the award ceremony in Stockholm on Dec. 10.