Alumni Profile
If it's November, this must be Antarctica
This alum's work takes him to environmental extremes
By Mary K. Miller
Photographs courtesy of Paul Ponganis
Here's a typical workday in November for alumnus Paul Ponganis, MD,
PhD: He wakes up, crawls out of his tent to brilliant Antarctic sunshine,
grabs a cup of coffee and checks on his study subjects, 10 plump and
healthy Emperor penguins. During the course of the day, he and his fellow
biologists from Scripps Institution at UC-San Diego might bring one of
the birds into their lab, place a homemade anesthesia mask over its long
beak and, after the gas takes hold, implant an ECG monitor under its
skin or attach a backpack for a video camera. After a quick recovery,
the penguin joins its companions in a fenced yard on the sea ice, complete
with two diving holes enabling the birds to go in and out of the water
at will. For the rest of the day, Ponganis monitors the physiology, behavior
and depth profiles of the penguins during their many foraging dives.
Here's a typical workday in May for this 1979 School of Medicine graduate:
He leaves home and battles bustling San Diego traffic to arrive at Sharp
Memorial Hospital, dons OR scrubs and administers anesthesia to his cardiac
surgery patient amid a team of six nurses and other doctors. He may participate
in several operations in a 12-hour day, during which he will monitor
his patient's heart and breathing rates and make sure the patient receives
enough life-giving oxygen. The surgical workload spans a wide range,
from routine operations to trauma and heart transplants.
Luckily for Ponganis, the two parts of his seemingly "schizo" lifestyle
as an Antarctic research biologist and private practice anesthesiologist
actually complement each other.
"My work with diving animals, staying up to date on current research
and the understanding I have of physiology makes me a much better clinician," he
says. "My medical background provides direction for my work with diving
physiology and lets me do these surgical procedures without harming the
animals."
It also helps that his medical colleagues are supportive of his other
line of work, which takes him away from the hospital for many months
each year. "Everyone in the Anesthesia Service Medical Group loves that
I do work in Antarctica," he says.
Extreme Animals
"My medical colleagues like to hear what's going on with the penguin
research and they are just amazed at the physiology of these animals
and what they can do," Ponganis says.
Emperor penguins, which live in the harsh conditions of Antarctica year
round, are the largest and most accomplished diving birds in the world.
On a single breath of air, they can dive to 1,500 feet. During a typical
dive, they stay underwater in freezing conditions for 12 minutes (the
record is 22 minutes). "We're very interested in how these animals have
adapted to stay underwater so long without breathing oxygen," Ponganis
says. "This is something my human patients could never tolerate."
Supported by the National Science Foundation, Ponganis and his colleagues
at Scripps hope that the work they do with diving animals in Antarctica
contributes to a better understanding of physiology as well as to potential
medical applications. Seals, whales and penguins can tolerate extreme
hypoxemia, in part because high levels of myoglobin allow them to store
more oxygen in their muscles, making them less dependent on blood oxygen
during dives. Ponganis is investigating myoglobin gene expression in
Emperor penguins, which have the highest concentrations of any species.
The ability of diving animals to survive long periods with low blood
flow (ischemia) might also lead the way to better treatments for shock
and stroke victims, who can suffer permanent damage when their brains
and other organs are oxygen-deprived. Low oxygen levels and ischemia
in humans can also lead to reperfusion injury, damage that occurs when
blood flow is cut off, then restored to organs. The cellular damage is
thought to arise from oxygen molecule free radicals, a reactive chemical
produced as a byproduct of biological activity. Emperor penguins somehow
avoid reperfusion injury despite severe organ ischemia and hypoxemia,
perhaps because their organs and tissues have naturally high levels of
antioxidants.
Ponganis is also researching the ability of penguins and seals to collapse
their lungs during deep dives and reinflate them at the surface. Chemicals
that line the lungs, called surfactants, are important in regulating
surface tension and controlling this process. "We're interested in the
chemical composition of surfactants and whether seals and penguins have
a higher concentration in their lungs than people do," Ponganis says. "Not
enough is known about surfactant function, and these animals give us
a good model for studying this function in extreme conditions. This understanding
could point the way to potential applications, including treatments for
respiratory distress syndrome in premature infants."
Complementary Careers
It may seem unusual for an MD to branch off into research biology but
for Ponganis it seems natural. He finished his doctoral dissertation
in animal physiology at UC-Santa Cruz in 1976 – during his first
year of medical school at Stanford.
"I was always interested in medicine, having a practice and working
with people. I was also intrigued by the difference between humans and
diving animals and needed a medical background to really understand the
physiology."
Ponganis completed an internship and residency in anesthesia at Stanford,
specializing in cardiac anesthesia. He joined the faculty there and seemed
set for a solid career in academic medicine. Then, in 1983, he accepted
an offer to work at Scripps with Gerald Kooyman, a leading authority
on diving physiology and a pioneer in the field.
"It was a hard decision to leave, but working with Gerry was a unique
opportunity," Ponganis says. "I always envisioned that I would work in
both animal physiology and medicine. There was an opening in a private
practice in San Diego, so this gave me the chance to do both."
Since 1983, Ponganis has been balancing the two careers, working at
the hospital in between research trips to far-flung parts of the world.
His research with seals and penguins has taken him to the Pribolof Islands
in Alaska, Lake Baikal in Siberia, the Galapagos Islands and Antarctica
where he spends three months a year studying Emperor penguins.
"These really are magnificent animals and I work in one of the most
peaceful, beautiful places on earth," Ponganis says. "It's both a challenge
and great fun to study these animals under natural conditions, diving
in the sea. The fact that I can return from Antarctica to a private practice
back home, I guess that makes my situation unique."
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