Levi-Montalcini, Rita, 1909-, Italian-American neurologist, b. Turin, Italy. A dual citizen of Italy and the United States, Levi-Montalcini did her most important work at Washington Univ. with Stanley Cohen. Studying mouse tumors implanted in chicken embryos, the pair isolated a nerve-growth factor, the first of many cell-growth factors found in animals. For this discovery Levi-Montalcini and Cohen were awarded the 1986 Nobel Prize in Physiology or Medicine.