Section 1 Virulence Factors and Pathogenicity of Helicobacter pylori.- Urease and Catalase as Virulence Factors of Helicobacter pylori.- Discussion.- Adhesion Properties of Helicobacter pylori.- Helicobacter pylori Hemagglutinins.- Discussion.- Cytotoxic Activity of Helicobacter pylori.- Discussion.- Helicobacter pylori and Gastric Mucus Integrity.- Discussion.- Helicobacter pylori and Other Gastric Spirilla: Similarities and Differences.- Further Observations on Human Spirobacteria.- Discussion.- Animal Models of Helicobacter pylori Gastritis.- Discussion.- Isotype and Specificity of Local and Systemic Anti-Helicobacter pylori Antibodies.- Discussion.- Section 2 Epidemiology of Helicobacter pylori.- Survival of Helicobacter pylori in the Aquatic Environment.- Discussion.- Helicobacter pylori in Human Populations: The Present and Predictions of the Future Based on the Epidemiology of Polio.- Discussion.- Transmission and Sources of Helicobacter pylori.- Discussion.- Chronic Gastritis: Epidemiology and Relationship to Peptic Ulcer Diseases.- Gastritis Epidemiology and Natural History.- Discussion.- Epidemiology of Gastric Metaplasia.- Discussion.- Epidemiology of Duodenal Ulcer Disease.- Discussion.- Section 3 Theoretical Site of Helicobacter pylori Therapy.- In Vitro Sensitivity of Helicobacter pylori.- Discussion.- Antibiotic Concentrations in Gastric Mucosa: The Guinea Pig Model.- Discussion.- Acquired Resistance to Antibiotics: An Underestimated Cause of Failure in the Treatment of Helicobacter pylori Infection.- Discussion.- Clinical Pharmacology of Bismuth - Studies from the Royal Free Hospital.- The Absorption of Bismuth from Orally Administered Tripotassium Dicitrato Bismuthate and Bismuth Subsalicylate.- Pharmacokinetics of Bismuth Compounds in Patients with Gastritis and Ulcer Disease During Standard Treatment.- Discussion.- Pharmacology and Safety of Bismuth Compounds.- Discussion.- Section 4 Clinical Trials for Helicobacter pylori Treatment.- Treatment Regimens to Eradicate Helicobacter pylori.- Discussion.- Effect of Eradication of Helicobacter pylori on Nonulcer Dyspepsia Syndrome and Chronic Gastritis.- Discussion.- Section 5 Optimal Design of Clinical Trials.- Histological Definition and Scoring of Gastritis.- Discussion.- Measuring Symptoms in Helicobacter pylori-Associated Gastritis and Non-Ulcer Dyspepsia.- Discussion.- Optimal Study Design for Therapeutic Trials in Helicobacter pylori- Associated Nonulcer Dyspepsia.- Discussion.- Optimal Design for Peptic Ulcer Studies.- Discussion.