Rosalyn Yalow, a pioneering American medical physicist and Nobel laureate, transformed medical diagnostics by enabling the accurate measurement of minuscule biological substances within the human body. This capability profoundly changed how many diseases were diagnosed and monitored, setting new standards in clinical medicine and research. Her contributions continue to influence healthcare practices today.
Early Life and Scientific Pursuits
Rosalyn Sussman Yalow was born in the Bronx, New York, in 1921. Her parents, despite lacking formal education, strongly supported her academic pursuits. She developed an early fascination with science, particularly mathematics and chemistry, nurtured at Walton High School. Her ambition to pursue physics deepened after reading Eve Curie’s biography of Marie Curie and attending a lecture by Enrico Fermi on nuclear fission.
Yalow attended Hunter College, graduating in 1941 as its first physics major. Despite concerns that graduate schools would not admit or fund a woman in physics, she secured a teaching assistantship at the University of Illinois at Urbana-Champaign. She was the only woman among 400 faculty members and teaching fellows in the College of Engineering’s physics program, a testament to her perseverance in a male-dominated field. She earned her Ph.D. in nuclear physics in 1945, becoming proficient in building and using instruments to measure radioactive substances, a skill that would prove significant in her later research.
Developing the Radioimmunoassay
Yalow’s groundbreaking work began at the Bronx Veterans Administration Hospital, where she joined in 1947 to explore the medical applications of radioactive substances. In 1950, she formed a collaborative partnership with Dr. Solomon Berson. Their initial laboratory space was an old janitor’s closet, yet from these humble beginnings, they embarked on research that would revolutionize diagnostic medicine.
Their primary challenge involved accurately measuring the concentration of substances like insulin, which are present in extremely small amounts in blood. Before their work, existing chemical techniques were often too insensitive or required large blood samples. Yalow and Berson devised a method known as radioimmunoassay (RIA) to overcome this limitation. This technique uses radioactive isotopes to “tag” a known quantity of a substance, such as insulin.
The core concept of RIA functions like a competition: unlabeled substances in a patient’s blood sample compete with the radioactively labeled substances for a limited number of binding sites on specific antibodies. By measuring the amount of radioactive substance that successfully binds to the antibodies, researchers can indirectly determine the concentration of the unlabeled substance in the patient’s sample. For instance, if a patient’s blood contains high unlabeled insulin, it occupies many antibody binding sites, leaving less room for radioactive insulin to bind; conversely, if levels are low, more radioactive insulin binds. This approach allowed for measurements down to a billionth of a gram, opening new avenues for understanding biological processes and diagnosing diseases.
The Widespread Impact of RIA
The radioimmunoassay technique developed by Yalow and Berson had a profound impact across various medical disciplines. This highly sensitive method transformed the ability to detect and quantify minute amounts of hormones, viruses, drugs, and other biological molecules in blood and other bodily fluids. Its applications quickly expanded far beyond the initial focus on insulin, making it a standard laboratory tool globally.
One significant application was in the screening of blood bank donations for the hepatitis virus, enhancing blood safety for transfusions. RIA also allowed for precise diagnosis of hormone-related disorders by accurately measuring hormone levels. This included conditions affecting the thyroid, such as hyperthyroidism and hypothyroidism, and reproductive disorders, which greatly improved diagnostic capabilities and patient management. The technique also enabled physicians to check levels of various vitamins and therapeutic drugs in the body, ensuring appropriate dosages and avoiding toxicity. Furthermore, RIA advanced cancer research and diagnosis by allowing the detection and monitoring of specific cancer markers, such as Prostate-Specific Antigen (PSA) and Carcinoembryonic Antigen (CEA).
Nobel Prize and Lasting Legacy
Rosalyn Yalow was awarded the 1977 Nobel Prize in Physiology or Medicine for her development of radioimmunoassays of peptide hormones. She was the second woman to win this Nobel category. Her long-term collaborator, Solomon Berson, was not a co-recipient as he had passed away in 1972, and Nobel Prizes are not awarded posthumously.
Yalow continued her research at the Bronx Veterans Administration Hospital, where she directed the Solomon A. Berson Research Laboratory, named in honor of her late colleague. She remained an active researcher until her retirement in 1991. Beyond her scientific achievements, Yalow advocated for women in science, serving as an inspiration. Her legacy extends through the medical advancements made possible by RIA and her enduring message: “The world cannot afford the loss of the talents of half of its people if we are to solve the many problems which beset us.”