Australians Barry J. Marshall and Robin Warren won the 2005 Nobel Prize in physiology or medicine for their work on how the bacterium helicobacter pylori plays a role in gastritis and peptic ulcer disease, the Swedish Nobel Assembly said Monday. The coveted award honoring achievements in medical research opened this year's series of prize announcements. It will be followed by prizes for 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 percent 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 etiology of these diseases."
