List of contents.- One: Methodology, Prevalence and Incidence of Gallstone Disease.- The GREPCO studies: methodology, prevalence and incidence data.- Prevalence and incidence of gallstone disease: the Sirmione study.- Gallbladder disease prevalence and cholecystectomy rates.- Prevalence of clinical gallbladder disease in Mexican Americans.- The Italian multicenter study on epidemiology and prevention of cholelithiasis (MICOL): ultrasonographic standardization.- Prevalence of gallstone disease in 18 Italian population samples: first results from the MICOL study.- Two: The Natural History of Gallstone Disease.- The natural history of gallstones: the GREPCO experience.- Natural history of gallstone disease: the Sirmione study.- 9. The outcome of gallstone disease in symptomatic and asymptomatic patients.- 10. Factors affecting the decision to undergo cholecystectomy for mildly symptomatic gallstones.- Three: Risk Factors for Gallstone Disease.- 11. Prevalence of gallstone disease in thalassaemia minor.- 12. Cholelithiasis and blood groups: evidence for a lack of association.- 13. Genetic, ethnic, and environmental factors: findings from the San Antonio heart study.- 14. Risk factors for gallstone disease: genetic, ethnic and environmental factors.- 15. Aging and gallstone disease.- 16. Gallstone prevalence in obese women: pathogenic role of hyperlipoproteinaemia and gallbladder motility.- 17. Serum lipids and gallstone disease.- 18. Dietary habits and gallstones: a study of male self-defense officials in Japan.- 19. Gallbladder and pregnancy.- 20. Risk factors for gallstone disease: the Sirmione study.- 21. Gallstones that form during rapid weight loss.- 22. Concluding remarks.

The meeting which took place in Rome on November 19th and 20th of 1982 is easily the best meeting on hepatic coma that I have ever attended, and I have attended many. It was an exceedingly we- planned meeting with prolonged opportunity for discussion, and there was genuine interplay and exchange of ideas (not the usual picture of a rushed meeting with investigators presenting their own point of view and talking past each other without a meaningful ex change) which took place in Rome. My co-editors and I hope that the published transcript, which of course can only reflect what transpired in Rome on those two days, does justice to a very intellectually exciting and gratifying ex change of ideas. L. Capocaccia, J. E. Fischer and F. Rossi-Fanelli v CONTENTS Introduction 1 SECTION 1: PATHOGENETIC PROBLEMS IN HEPATIC ENCEPHALOPATHY Ammonia: The old and the new * * . * * * . * . * * * . * . * 5 L. Zieve Role of synergism in the pathogenesis of hepatic encephalopathy * * * * . * * . . . . * 15 L. Zieve y-Aminobutyric acid receptors in experimental hepatic encephalopathy *. *. * * 25 M. L. Zeneroli, ~. Baraldi,and E. Ventura A possible role for excitatory neurotoxic amino acids in the pathogenesis of hepatic en 41 cephalopathy * * * * * * * * * * * * * * * F. Moroni, G. Lombardi, G. Moneti, D. Pellegrini and C.