In August 1991 — on the same day that an attempted coup by communist hardliners ushered the collapse of the Soviet Union — Dmitriy Yablonskiy, Ph.D., took the biggest gamble of his life. He put himself and his family on a plane to America from Kharkov, their home in the Soviet Socialist Republic of Ukraine.
Yablonskiy and his family — wife, Larisa; daughter, Nadia; and parents, Arkadiy and Eugeniya — did not speak English, and he had made no arrangements for a job in the United States.
But regardless of the tremendous linguistic and cultural obstacles they would face, Yablonskiy, a distinguished theoretical physicist, felt certain life would be better for his family in the United States rather than in the rapidly disintegrating Soviet Union.
“At that point in time, the economic situation had become so bad that there was absolutely no appreciation for science,” Yablonskiy recalls. “We had to get out.”
In the Ukraine, Yablonskiy chaired a research division, authored more than 100 scientific papers and won the republic’s highest physics medal, so he felt comfortable he could find a job in physics research at an American university. What he hadn’t counted on was a flood of U.S. physicists looking for new jobs as a result of the end of the Cold War.
“I was sending my applications to different places, and I would usually get a response that went something like this: ‘Dear Dr. Yablonskiy, we are very impressed with your credentials, but we have 800 applications for this position. We will keep your CV on file,'” he explains.
Eventually, Yablonskiy had to make ends meet with welfare and a job driving cabs. And for a while, his dream of making a new life for his family looked very bleak.
Now a professor of radiology in the School of Medicine and of physics in Arts & Sciences, Yablonskiy will talk about the difficulties of his early days in the United States, but he’d much rather savor his amazement at his current situation.
Although he has no formal training in biology or medicine, the highly collaborative environment at the School of Medicine has allowed him not just to survive but also to prosper as a researcher and a faculty member.
“I am a physicist,” says Yablonskiy, a soft-spoken thin man who still speaks with a Russian accent. “I really know very little about biology and medicine. And yet here I am working with so many prominent people who know quite a bit about biology and medicine. This is probably the best place for me to work.”
Yablonskiy’s colleagues are equally pleased with the expertise he brings to their research efforts.
“Working with Dmitriy is so much fun that sometimes I want to go back to college and earn a physics degree,” says frequent collaborator Joseph J.H. Ackerman, Ph.D., the William Greenleaf Professor and chair of the Department of Chemistry in Arts & Sciences and a professor of radiology.
“Dmitriy is really a very remarkable fellow,” says another frequent collaborator, Marc E. Raichle, M.D., professor of radiology, of neurology and of anatomy and neurobiology.
“Through his own determination and skills, he has risen to the rank of fully tenured professor faster than anyone I’ve ever known in my 30 years here.”
Physics on the brain
Yablonskiy found a second career in biomedicine on an insight he developed in Cleveland more than a decade ago.
Frustrated with his unsuccessful attempts to get a job in a physics department, Yablonskiy started talking to radiologists at Case Western Reserve University.
One of the most important tools in radiology research, magnetic resonance imaging (MRI), produces images of the body by measuring water molecules’ responses to strong magnetic fields. Yablonskiy’s work in physics had focused on the properties of objects in magnetic fields.
At Case Western’s radiology department, Yablonskiy spoke with the department chair, John Haage, M.D., and with E. Mark Haacke, Ph.D., also a trained physicist. Together, they were able to create a position for him.
“It was a very, very entry level position, with almost no pay,” Yablonskiy recalls, laughing, still clearly grateful for the opportunity in spite of the limited compensation.
After Yablonskiy came to Washington University in 1993 as a research associate at the Mallinckrodt Institute of Radiology, he soon began working on a controversial scientific puzzle that resulted from the research of radiology colleague Raichle.
In 1986, Raichle led a study of brain activity and blood flow. The study confirmed that activity in a given region of the brain increases blood flow to that region, but it found a surprisingly small increase in the region’s consumption of oxygen.
Neuroscientists had long assumed that blood flow increases to active brain cells to supply them with more sugar and oxygen, the fuels they need to work. The disparity between blood flow increase and the increase in oxygen consumption cast doubt on that theory.
Coming at the problem from a physics perspective, Yablonskiy noted that the chemical reactions brain cells use to do work have to produce heat.
“If you did not remove this heat, the brain would explode, basically,” he explains. “Every five minutes, the temperature of the brain would increase by one degree, and that heat cannot just go away through the surface of the brain.”
Years at the University: 12
University titles: Professor of radiology in the School of Medicine and of physics in Arts & Sciences
Hometown: Kharkov, Ukraine
Native language: Russian
Family: Wife, Larisa; daughter, Nadia
Hobbies: Enjoying the outdoors with his family, going to movies, traveling and spending time close to Mother Nature in parks and near the ocean.
Yablonskiy theorized that increased blood flow takes away heat, acting as a coolant for active regions of the brain. He developed a model of brain temperature regulation and made predictions for how much temperature would increase in blood flow returning from the brain vs. blood flow going to the brain.
Those predictions have been verified by direct measurements of blood flow temperature by researchers in Denmark and by human MRI studies conducted by Yablonskiy and his colleagues.
“It was a sophisticated experiment, and potentially there were a number of ways you could interpret the MRI data we produced,” he says.
“But when I first presented the data at a meeting, I went to other researchers and asked them if they could come up with any other explanations, and all of them said ‘no.'”
Through continued study of humans and animals, Yablonskiy and Alex Sukstanskii, Ph.D., senior research scientist, are working to develop a more general theory of brain temperature regulation. They have shown that blood flow tightly protects the human brain from temperature changes in the environment.
“If you heat the brain externally, the heat will only go 3 to 4 millimeters deep, while the remaining 15 to 16 centimeters will stay at the same temperature,” he explains.
Yablonskiy and Sukstanskii hope to lay the groundwork that may one day enable scientists to answer one of the most basic brain temperature questions: Throughout evolutionary history, why has the brain always been kept in such a narrow temperature window?
“In most species, humans and animals, the brain is always kept between 36 and 38 degrees Celsius (96.8 and 100.4 Fahrenheit),” Yablonskiy explains. “Why this narrow window? It’s a very basic and very interesting question that is still up in the air.”
Yablonskiy’s research also has applications in clinical treatment. In the past decade, neurologists have become interested in using hypothermia to slow brain injury.
Cold slows the rate of chemical reactions that drive metabolism, potentially slowing the chemical chain reactions that can cause injury in patients with stroke and other brain trauma. Yablonskiy and Sukstanskii are helping scientists consider their options for creating such cooling effects in the brain.
In addition to his work with Raichle and Ackerman, Yablonskiy is adapting MRI for use in analyzing the microstructure of the lungs of emphysema patients.
The project is another example of the collaborative atmosphere that he loves at the University. His colleagues on this research include Mark S. Conradi, Ph.D., professor of physics; Joel D. Cooper, M.D., the Evarts A. Graham Professor of Surgery and head of cardiothoracic surgery; and Stephen S. Lefrak, M.D., professor of medicine and assistant dean for the humanities program in medicine.
“Dmitriy’s ability to reach out and communicate with other people is amazing,” Raichle says. “He’s not the least bit afraid to get deeply involved in efforts to tackle biologically significant problems. He’s willing to roll up his sleeves and become a significant contributor.”