Kendric Smith

Kendric Smith, PhD, emeritus professor of radiation oncology at Stanford Medicine, died in Los Gatos, California, on Nov. 1 at the age of 98.

Smith, who joined the Stanford School of Medicine in 1956, was known for his research on DNA repair after radiation exposure and for his many books on photobiology - a field devoted to studying the interactions of light with living organisms. Smith, who authored hundreds of research papers, founded the American Society of Photobiology in 1972 and served as its first president.

"Kendric Smith was a trailblazing researcher into the effect of radiation on living organisms," said Lloyd Minor, MD, the dean of the school of medicine and vice president of medical affairs for Stanford University. "His hundreds of research papers and textbooks on DNA synthesis, damage and repair laid the groundwork for our modern understanding of cancer biology and radiotherapies."

Smith began his career at the Stanford University School of Medicine in 1956 as a research associate with Henry Kaplan, MD. Kaplan founded the school's department of radiology and was at the time developing the first high-energy linear accelerator for therapeutic use. "My first task was to develop a method for fractionating DNA and RNA from normal and tumor cells to see if differences could be observed," Smith recalled in a written memoir on his website. These experiments led to his discovery in the late 1950s that small RNA molecules known as transfer RNAs bound to specific amino acids during protein synthesis.

Although Smith's research proceeded in different directions, the discovery and characterization of the amino acid-specific tRNAs was recognized with the Nobel Prize in physiology or medicine awarded to three other scientists in 1968.

Smith's subsequent studies focused on the effect of radiation of varying wavelengths - including ultraviolet radiation and X-rays - on DNA and RNA. His discovery that UV irradiation of bacteria can cause linkages to form between DNA and proteins and disrupt DNA replication led him to explore and delineate many molecular pathways involved in DNA damage repair.

Smith was also knowledgeable about the use of low-level light therapy (often delivered via lasers) to treat a variety of health conditions. He participated in a number of scientific meetings in which he described his role as one to teach physicians and engineers what he referred to as the first law of photochemistry: Light must be absorbed before photochemistry can occur. If the wavelength of the light used is not able to penetrate a tissue, it will not have a biological effect.

"I also had to 'try' to teach them that lasers are not magical; lasers are just expensive flashlights," Smith recalled. "It is the light that lasers emit that produces the biological effect, not the laser itself. The only way to get a biological effect just from a laser is to drop it on your foot." Smith urged researchers to always note the specific wavelength of the light used in every experiment.

'Computer nerd'

Smith became interested in computer programming in the late 1970s, and in 1986 he launched a program called Grant Tracker to perform bookkeeping tasks for the multiple research grants he had received from the National Institutes of Health. In 1987 he began selling the program to other researchers, and regular updates to the program were made over the next 14 years until 2000, when Smith made the program freely available online. 

After his retirement from Stanford in 1993, Smith remained in active contact with his colleagues. He also continued to enjoy his work as a "computer nerd" as he described himself, creating websites for many organizations. He became an avid birder and traveled with his wife on birdwatching trips to Brazil, Ecuador, Cuba, Peru, Mexico and Japan. He also became interested in the life cycle of the monarch butterfly, which he raised and released near his Los Gatos home. 

When asked in a 2014 article in the American Society of Photobiology newsletter what his birdwatching and his interest in the life cycle of the monarch butterfly had in common with scientific research, Smith replied, "Well, it comes down to inquisitiveness, which is part of science. Be it birds' migratory patterns or butterfly life cycles, it comes down to figuring out how things can possibly do what they do."

Smith was born and raised in Illinois. He completed the first three years of his undergraduate degree at Berea College in Kentucky before transferring to Stanford University to complete his bachelor's degree in chemistry. He graduated from the University of California, Berkeley, with a PhD in biochemistry in 1952. He remained at Berkeley as a postdoctoral scholar, where he characterized the first high-molecular weight RNA from yeast, until he joined UC San Francisco as a research associate in 1954. In 1956, he joined the Stanford University School of Medicine, then located in San Francisco.

Asked if he had advice for young scientists, Smith replied, "Just do whatever research you are most interested in. Pursue it even if it is not the best way to make money because if it makes you happy that is the best thing." 

Smith was preceded in death by his wife of 62 years, Marion. He is survived by two daughters, Nancy and Martha, and five grandchildren.