[1] Univ Calif San Francisco, Div Gastroenterol & Hepatol, Dept Med, 513 Parnassus Ave,Box 0538, San Francisco, CA 94143 USA
[2] Stanford Univ, Dept Med, Div Gastroenterol & Hepatol, Palo Alto, CA 94304 USA
[3] Univ Alberta, Div Gastroenterol, Liver Unit, Edmonton, AB, Canada
[4] Oregon Hlth & Sci Univ, Sch Nursing, Portland, OR 97201 USA