The American physicist Rosalyn S.Yalow (born 1921) made her most outstanding contribution to modern medicine in developing radioimmunoassay (RIA), for which she received a Nobel Prize in physiology/medicine (1977).

Rosalyn S.Yalow was born in New York City on July 19, 1921, the second child and only daughter of Simon Sussman and Clara Zipper. Her mother came to America from Germany at the age of four. Her father was born on the Lower East Side of New York. In her early childhood she was already an avid reader. Having no books at home, she took weekly trips to the public library with her brother, Alexander.

As she recalled, mathematics fascinated her while in the seventh grade. Later, at Walton High School, she was attracted to chemistry by an outstanding teacher, Mr. Mondzak. Her interest in physics developed at Hunter College, where two of her professors, Herbert N. Otis and Duane Roller, played a vital role.

Looking back to the end of the 1930s, Yalow recollected physics, particularly nuclear physics, as the most exciting field in the world. Madame Marie Curie's biography, written by her daughter Eve, had just been published. Yalow believed that this book ought to be read by every young aspiring woman scientist. Enrico Fermi's colloquium on the discovery of nuclear fission in January 1939 remained another highlight for her.

Yalow was convinced her career would be in physics. Her family thought the position of elementary school teacher might be more appropriate. She prevailed due to encouragement from her physics professors. On her graduation (A.B. in physics and chemistry) from Hunter College in January 1941, she went to business school, but only for a short time. In mid-February 1941 an offer came to be an assistant in physics at the University of Illinois in Champaign-Urbana. When she arrived there in September 1941, the faculty of the College of Engineering was composed of 400 members. She discovered she was the only woman and the first since 1917.

On the first day of graduate school she met Aaron Yalow. He had come to Illinois to start graduate study in physics. They married on June 6, 1943. They had two children: Benjamin, a systems programmer, and Elanna, an educational psychologist.

Yalow received an M.S. in physics in 1942 and a Ph.D. in nuclear physics in January 1945, both from the University of Illinois. She had been an instructor there in 1944 and 1945. Her thesis director, Maurice Goldhaber, later became director of Brookhaven National Laboratories. Yalow acknowledged the support and encouragement that he and his wife, Gertrude Goldhaber, herself a distinguished physicist, gave to her.

In January 1945 she went back to New York as an assistant engineer at the Federal Telecommunications Laboratory. In this ITT research laboratory she was the only woman engineer.

In 1946 she returned to Hunter College as a lecturer and temporary assistant professor in physics and stayed there until the spring semester of 1950. In this women's college (now part of the City University of New York) she taught physics not to women, but to veterans in a pre-engineering program. In December 1947 she joined the Bronx Veterans Administration (VA) Hospital as a part-time consultant. She equipped and developed the Radioisotope Service. She started research projects together with Bernard Roswit, chief of the Radiotherapy Service, and with other physicians in various clinical fields. The Bronx VA's Radioisotope Service was one of the first supported by the VA under a new national plan of development.

In January 1950 Yalow decided to renounce teaching and stay with the VA on a full-time basis. In the spring of 1950 she met Solomon (Sol) A. Berson, then completing his residency in internal medicine. In July 1950 Berson joined her service, and they began a close collaboration which lasted 22 years until his death on April 11, 1972. As Yalow wrote in 1979, "A multidisciplinary approach is necessary to weave the tools and concepts of physics into medicine. Maximal effectiveness is achieved only when each member of an interdisciplinary team makes a commitment to at least on-the-job training in the discipline of the other(s).... I learned medicine and [Berson] showed a remarkable talent for physics and mathematics. We learned to talk the same hybrid language--a major factor in our success as a research team."

In 1968 Berson became chairman of the Department of Medicine at the Mount Sinai School of Medicine. Had Berson lived longer, as Yalow noted, he would have shared the Nobel Prize. As a memorial tribute, Yalow requested her laboratory to be designated the Solomon A. Berson Research Laboratory so that his name would appear in her articles as long as she published.

Their investigations dealt with the application of radioisotopes to blood volume determination, clinical diagnosis of thyroid diseases, and the kinetics of iodine metabolism. They extended these techniques to the study of the distribution of globin (because of its possible use as a plasma expander), serum proteins, and smaller peptides, the hormones. The most readily available highly purified hormone was insulin. On the basis of the delayed rate of insulin disappearance from the circulation of insulin-treated subjects, they deduced that these patients develop antibodies to the animal insulins. While studying the reaction of insulin with antibodies they realized they had a potential tool for measuring circulating insulin. Several additional years of work were necessary to achieve the practical measurement of plasma insulin in humans. Yalow considered that the era of radioimmunoassay genuinely opened in 1959. By the mid-1980s RIA was used to measure hundreds of substances of biological interest in thousands of laboratories in all parts of the world.

In 1977 Yalow was awarded the Nobel Prize in medicine/physiology. From 1974 to mid-1985, 37 honorary degrees were conferred upon her. The honors bestowed upon her included membership in the National Academy of Sciences (1975) and the American Academy of Arts and Sciences (1979). She was also a foreign associate of the French Academy of Medicine (1981). Beginning in 1972 Yalow was the senior medical investigator at the VA, and beginning in 1973 she was director of the Solomon A. Berson Research Laboratory at the VA Hospital in the Bronx.

In 1995 Yalow was one of fourteen eminent scientists and six Nobel laureates who joined the American Medical Association and the California Medical Association in filing briefs with the California Supreme Court stating they could find no link between electric and magnetic fields (EMF) from power lines and cancer. The briefs were filed in a homeowner's suit against San Diego Gas & Electric, charging that nearby power lines had devalued luxury homes. She was still at the Mt. Sinai School of Medicine. Her report stated "no scientifically documented health risk has been associated with the usually occurring levels of electromagnetic fields."

Further Reading

• Yalow is listed in Who's Who of American Women (14th edition, 1985-1986) and in Who's Who in America (43rd edition, 1984-1985). An autobiographical sketch was published by the Nobel Foundation under the title Les Prix Nobels/The Nobel Prizes 1977 (1978). For Yalow's vision on women and science and the future of humanity, see her Nobel address. She gave a detailed account of her researches and discoveries in "A physicist in biomedical investigation," in Physics Today, 32 (October 1979). Eugene Straus, who worked with Yalow for 15 years and served as physician to her mother and son, completed an engaging biography, Rosalyn Yalow, Nobel Laureate: Her Life and Work in Medicine (1998).