Fellow American College of Physicians (member medical self-assessment committee), Infectious Diseases Society of America (councillor 1983-1985). Member American Society for Clinical Investigation, American Federation for Clinical Research, American Society for Microbiology, Western Society for Clinical Research, International Immunocompromised Host Society, British Society Antimicrobial Chemotherapy.
Intern, junior assistant resident, senior assistant resident medical division, Bellevue Hospital and Memorial Hospital, New York City, 1964-1967;fellow in medicine, Cornell Univercity Medical College, 1965-1967;epidemic intelligence officer bacterial diseases branch, National Communicable Disease Center, Atlanta, 1967-1969;chief special pathogens section, National Communicable Disease Center, Atlanta, 1968-1969;special postdoctoral research fellow, National Institute Allergy and Infectious Diseases, 1969-1970;research fellow in medicine, Memorial Hospital/Cornell Univercity Medical College, 1969-1970;clinical assistant physicisn infectious disease service department medicine, Memorial Hospital, 1970-1972;associate director microbiology laboratory, Memorial Hospital, 1971-1972;instructor in medicine, Cornell Univercity Medical College, 1970-1972;assistant clinician, Sloan-Kettering Institute for Cancer Research, 1971-1972;chief division infectious disease, California Pacific Medical Center, San Francisco, since 1985;director, Kuzell Institute, San Francisco, since 1985. Adjunct Professor pharmacy University of Pacific, San Francisco, since 1989. Member microbiology and invectious diseases advising committee National Institute Allergy and Infectious Diseases, 1981-1985, member allergy and immunology research committee, 1975-1979.
Member of staff California Pacific Medical Center, Mount Zion Hospital and Medical Center, University of California, San Francisco. Member science advisory board American Foundation for Acuired Immune Deficiency Syndrome Research.