1.   All patients had histological and cholangiographic findings consistent with PSC, other inclusion and exclusion criteria have been described previously.

2.   The exclusion criteria for the selection of controls were constipation or other gastrointestinal problems.

3.   Exclusion criteria included previous gastric surgery, known bleeding diathesis, oral anticoagulation, or recent treatment with bismuth compounds, antisecretory agents, or antibiotics.

4.   A number of so-called exclusion criteria have been established to narrow the field.