- 2007 - presentPresidentAmerican Gastroenterological Association 
- 2005 - presentVice PresidentGoverning Board, American Gastroenterological Association 
- 2005Vice PresidentAmerican Gastroenterological Association 
- 2004 - 2005MemberFutures Committee, American Gastroenterological Association 
- 2004MasterAmerican College of Physicians 
- 2004ChairFutures Committee, American Gastroenterological Association 
- 2004MemberLeadership Committee, American Gastroenterological Association 
- 2004MemberScientific Advisory Committee, The Morgan Foundation for the Study of PSC 
- 2004 - presentMemberHepatobiliary Pathophysiology Study Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health 
- 2003MemberFoundation Corporate Gift Committee, American Gastroenterological Association 
- 2002FellowAmerican College of Physicians 
- 2002MemberGoverning Board, American Gastroenterological Association 
- 2002 - presentMemberAmerican College of Physicians 
- 2001Chair and OrganizerAnnual Single Topic Research Conference, American Association for the Study of Liver Diseases 
- 2001MemberAnnual Single Topic Research Conference, American Association for the Study of Liver Diseases 
- 2001MemberCommittee on Publications and Informatics, American Gastroenterological Association 
- 2001MemberNominating Committee, American Clinical and Climatological Association 
- 2001MemberSingle Topic Research Conference (The Pathobiology of Biliary Epithelia), American Association for the Study of Liver Diseases 
- 2001 - presentMemberBoard of Directors, Office of Intellectual Property (formerly Mayo Medical Ventures) 
- 2000ChairPublications Committee, Association of Professors of Medicine 
- 2000MemberBoard of Directors, Association of Professors of Medicine 
- 2000MemberSingle Topic Research Conference (Primary Sclerosing Cholangitis: Consensus and Controversies), American Association for the Study of Liver Diseases 
- 2000 - presentMemberMayo Clinic Chapter, Sigma Xi, The Scientific Research Society 
- 1999MemberPublications Committee, Association of Professors of Medicine 
- 1999 - presentChairDepartment of Internal Medicine 
- 1999 - presentMemberAssociation of Professors of Medicine 
- 1998MemberClinical Investigator Evaluation Task Force, Institutional Research Committee, Mayo Clinic Committees 
- 1998MemberPractice Integration Work Group, Mayo Clinic Task Forces/Work Groups 
- 1998MemberAdvisory Committee, Digestive Diseases Interagency Coordinating Committee, National Institutes of Health 
- 1997 - 1999MemberFinance Committee, Department of Internal Medicine 
- 1997 - 1999Vice ChairDepartment of Internal Medicine 
- 1997 - 1998ChairInstitutional Task Force on Centers, Mayo Clinic Task Forces/Work Groups 
- 1997 - 1998MemberPolicy Task Force on Scientific Integrity in Research and Publications, Mayo Clinic Task Forces/Work Groups 
- 1997 - 1998MemberInstitutional Task Force on Centers, Mayo Clinic Task Forces/Work Groups 
- 1997MemberPersonnel Committee - Rochester, Mayo Clinic Rochester Committees 
- 1997MemberAdministrative Committee of the Board of Governors, Board of Governors, Mayo Clinic Rochester Committees 
- 1997MemberSearch Committee for the Director of the Division of Gastroenterology, The Johns Hopkins University School of Medicine 
- 1996 - 2001MemberPresidents National Advisory Council, New York Medical College 
- 1996 - 1998MemberInstitutional National Strategies Committee, Mayo Clinic Committees 
- 1996 - 1998MemberGoverning Board, Federated Societies of Gastroenterology and Hepatology 
- 1996 - 1998MemberBoard of Directors, American Digestive Health Foundation 
- 1996 - 1997PresidentAmerican Association for the Study of Liver Diseases 
- 1996MemberClinical Investigator Evaluation Task Force, Institutional Research Committee, Mayo Clinic Committees 
- 1996External ConsultantLiver Center, University of California, San Francisco 
- 1996MemberLiver Center, University of California, San Francisco 
- 1996MemberAnnual Post-graduate Course (Diseases of the Bile Ducts: Pathogenesis, Pathology and Practice), American Association for the Study of Liver Diseases 
- 1995 - 1996President-ElectAmerican Association for the Study of Liver Diseases 
- 1994ReviewerJohn Sealy Memorial Endowment Fund for Biomedical Research, Medical Branch, University of Texas, Galveston 
- 1994MemberJohn Sealy Memorial Endowment Fund for Biomedical Research, Medical Branch, University of Texas, Galveston 
- 1994MemberAnnual Single Topic Research Conference (The Pathobiology of Biliary Epithelia), American Association for the Study of Liver Diseases 
- 1994 - presentFounderCholangiopathy Interest Group, Division of Gastroenterology and Hepatology, Department of Internal Medicine 
- 1994 - presentMemberCholangiopathy Interest Group, Division of Gastroenterology and Hepatology, Department of Internal Medicine 
- 1993 - 2001MemberExtramural Advisory Committee, Liver Research Core Center, Yale University School of Medicine 
- 1993 - presentMemberItalian Society of Gastroenterology 
- 1992 - 2000MemberGoverning Board, American Association for the Study of Liver Diseases 
- 1992MemberClinical Investigator Evaluation Task Force, Institutional Research Committee, Mayo Clinic Committees 
- 1991 - 1993MemberCommittee on Career Paths for Clinical Research, Institute of Medicine, National Academy of Sciences 
- 1991 - 1993MemberNational Board of Visitors, New York Medical College 
- 1991MemberItalian Liver Foundation 
- 1990 - 2002DirectorCenter for Basic Research in Digestive Diseases 
- 1990 - 1999ChairDivision of Gastroenterology and Hepatology, Department of Internal Medicine 
- 1990MemberAnnual Research Workshop (The Pathobiology of Biliary Epithelia), American Association for the Study of Liver Diseases 
- 1990 - presentMemberInstitutional Research Committee, Mayo Clinic Committees 
- 1990 - presentMemberCenter for Basic Research in Digestive Diseases 
- 1990 - presentMemberReviewers Reserve, National Institutes of Health 
- 1989 - 1993ChairSteering Committee, Cell Biology Interest Group, Mayo Clinic Committees 
- 1989 - 1993MemberCell Biology Interest Group, Mayo Clinic Committees 
- 1989 - 1993MemberSteering Committee, Cell Biology Interest Group, Mayo Clinic Committees 
- 1989 - 1990MemberIndustry/Scholar Award Selection Committee, American Gastroenterological Association 
- 1989FounderCell Biology Interest Group, Mayo Clinic Committees 
- 1989 - presentMemberAssociation of American Physicians 
- 1989 - presentMemberAmerican Clinical and Climatological Association 
- 1988 - 1990ChairResearch Committee, American Gastroenterological Association 
- 1988 - 1990MemberGoverning Board, American Gastroenterological Association 
- 1988 - 1990MemberSteering Committee, Gastroenterology Research Group 
- 1988 - 1990MemberPublic Policy Committee, American Gastroenterological Association 
- 1988MemberAnnual Graduate Course (Diagnosis and Management of Diseases of the Biliary Tract), American Gastroenterological Association 
- 1987 - 1999MemberAdministrative Committee, Department of Internal Medicine 
- 1987 - 1990MemberResearch Committee, American Association for the Study of Liver Diseases 
- 1987 - 1990Vice Chair for ResearchDepartment of Internal Medicine 
- 1987 - 1990MemberExecutive Committee, Department of Internal Medicine 
- 1987 - 1989ChairGrants Review Committee, American Liver Foundation 
- 1987 - 1989MemberBoard of Directors, American Liver Foundation 
- 1987MemberNominating Committee, American Gastroenterological Association 
- 1987 - presentMemberDepartment of Internal Medicine 
- 1986 - 1990MemberGI Subspecialty Training Committee, Division of Gastroenterology and Hepatology, Department of Internal Medicine 
- 1986 - 1990ChairExtramural Advisory Committee, Liver Research Core Center, University of Minnesota Medical School 
- 1986 - 1990MemberGeneral Medicine A-2 Study Section, Gastroenterology and Clinical Nutrition, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health 
- 1986 - 1990MemberExtramural Advisory Committee, Liver Research Core Center, University of Minnesota Medical School 
- 1986 - 1990MemberResearch Committee, American Gastroenterological Association 
- 1986ChairScientific Awards Selection Committee, Mayo Clinic Alumni Association, Mayo Clinic College of Medicine and Science 
- 1986MemberScientific Awards Selection Committee, Mayo Clinic Alumni Association, Mayo Clinic College of Medicine and Science 
- 1985 - presentMemberGastroenterology Research Group 
- 1984 - 1989MemberAmerican Liver Foundation 
- 1984 - 1989MemberGrants Review Committee, American Liver Foundation 
- 1984 - 1986Vice ChairInstitutional Review Board, Mayo Clinic Committees 
- 1984 - 1985MemberInstitutional Steering Committee on Liver Transplantation, Institutional Dialysis and Transplant Committee, Mayo Clinic Committees 
- 1984 - 1985MemberNominating Committee, American Association for the Study of Liver Diseases 
- 1984 - presentMemberAmerican Society for Clinical Investigation 
- 1983 - 1990Co-DirectorAdvanced Hepatology Training Program, Mayo School of Graduate Medical Education, Mayo Clinic College of Medicine and Science 
- 1983 - 1990MemberAdvanced Hepatology Training Program, Mayo School of Graduate Medical Education, Mayo Clinic College of Medicine and Science 
- 1983 - 1986MemberInstitutional Review Board, Mayo Clinic Committees 
- 1982 - 1985MemberResearch Committee, American Association for the Study of Liver Diseases 
- 1982 - presentMemberAmerican Society for Cell Biology 
- 1980 - 1981MemberResearch Committee, Division of Gastroenterology and Hepatology, Department of Internal Medicine 
- 1980Ad Hoc MemberBiomedical Research Review Committee, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health 
- 1980MemberBiomedical Research Review Committee, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health 
- 1980 - presentMemberInternational Association for the Study of the Liver 
- 1979 - 1982MemberCentral Society for Clinical Research 
- 1979 - 1982MemberTraining and Education/Education Committee, American Association for the Study of Liver Diseases 
- 1979ChairAnnual Meeting Scientific Program, Mayo Clinic Alumni Association, Mayo Clinic College of Medicine and Science 
- 1979MemberAnnual Meeting Scientific Program, Mayo Clinic Alumni Association, Mayo Clinic College of Medicine and Science 
- 1978 - 1985MemberMidwest Gut Club 
- 1977 - 1982MemberSigma Xi, The Scientific Research Society 
- 1977ConsultantGastrointestinal Drugs Advisory Committee, Food and Drug Administration 
- 1977MemberHarvey Society 
- 1977MemberGastrointestinal Drugs Advisory Committee, Food and Drug Administration 
- 1977 - presentMemberMayo Clinic Alumni Association, Mayo Clinic College of Medicine and Science, Department of Education Administration 
- 1977 - presentMemberDivision of Gastroenterology and Hepatology, Department of Internal Medicine 
- 1976 - 1988MemberAmerican Federation for Clinical Research 
- 1976 - presentMemberAmerican Gastroenterological Association 
- 1975 - 1977MemberNew York Lipid Research Club 
- 1975 - presentMemberAmerican Association for the Study of Liver Diseases 
- 1973 - 1974MemberResidency Review Committee, Education Committee, Mayo Graduate School of Medicine 
- 1972 - 1973MemberEducation Committee, Mayo Graduate School of Medicine, Mayo Clinic College of Medicine and Science 
- 1972 - 1973MemberMethods of Training in Internal Medicine Committee, Education Committee, Mayo Graduate School of Medicine 
-  MemberFinance Committee - Rochester, Mayo Clinic Rochester Committees 
-  Chair and OrganizerAnnual Single Topic Research Conference (The Pathobiology of Biliary Epithelia), American Association for the Study of Liver Diseases 
-  Chair and OrganizerAnnual Research Workshop (The Pathobiology of Biliary Epithelia), American Association for the Study of Liver Diseases 
-  DirectorAnnual Post-graduate Course (Diseases of the Bile Ducts: Pathogenesis, Pathology and Practice), American Association for the Study of Liver Diseases 
-  Co-DirectorSingle Topic Research Conference (Primary Sclerosing Cholangitis: Consensus and Controversies), American Association for the Study of Liver Diseases 
-  Chair and OrganizerSingle Topic Research Conference (The Pathobiology of Biliary Epithelia), American Association for the Study of Liver Diseases 
-  DirectorAnnual Graduate Course (Diagnosis and Management of Diseases of the Biliary Tract), American Gastroenterological Association 
-  External ConsultantSearch Committee for the Director of the Division of Gastroenterology, The Johns Hopkins University School of Medicine 
-  MemberLeadership Cabinet, American Gastroenterological Association