CAPE CANAVERAL, Fla., Jan. 20 (UPI) -- More than a decade ago, Millie Hughes-Fulford used samples of her own blood drawn while she was flying in space aboard the shuttle for an experiment about how microgravity affects the immune system.
She followed the research after her mission and today is among the scientists continuing the study using the Columbia astronauts as subjects.
"It's come full circle," said Hughes-Fulford, a payload specialist on a June 1991 shuttle mission who now directs of the Laboratory of Cell Growth at the University of California Medical School, San Francisco.
The work, which is jointly sponsored by NASA and the European Space agency, focuses on T-cell activation, the linchpin of the immune system. The nearly total loss of T-cell activation in microgravity was discovered in a 1983 Spacelab mission and later confirmed by several space experiments. Microgravity's affect on the immune system, however, dates back to the earliest days of human spaceflight.
"The Apollo astronauts came back with an altered immune response," Hughes-Fulford said in an interview with United Press International. "Their lymphocytes (white blood cells) didn't activate properly."
The astronauts' immune systems recovered after about seven days, she added.
Swiss scientist August Cogoli started isolating individual cells for further study in 1982. Purified human T-cells are flying on Columbia, one of about 80 experiments planned during the 16-day shuttle mission. The researchers' goals are to study selected critical steps in T-cell activation, test theories of what is causing the T-cell to deactivate, and identify when during the acclimation to microgravity the cell is affected.
Scientists hope that studying how the immune system in healthy people turns off in microgravity and reactivates upon return to Earth will broaden understanding and treatments of immune system disorders afflicting non-astronauts.
"There are many aspects of space we can't mimic on Earth," said John Charles, NASA's mission scientist for the biological and physical science experiments flying aboard Columbia. "We can turn down air pressure in laboratory vacuum chambers and bombard samples with space-like radiation. But we can't turn off gravity."
Other biological experiments under way aboard Columbia include:
-- tracing how the bones lose calcium in microgravity. Astronauts on Saturday took oral calcium tracers that will be monitored throughout the mission to probe how calcium metabolism changes in an astronaut's body during spaceflight.
-- double-blind tests to determine if potassium citrate can help prevent the formation of kidney stones. Some of the Columbia crewmembers are getting the supplement; others are taking a placebo pill.
"We have previously, during Mir and other flights, demonstrated that there is a greater risk of forming renal (kidney) stones during flight -- as well (during) the first week or so after landing," said principal investigator Peggy Whitson, a NASA astronaut and scientist who returned last month from a six-month stay on the space station.
"Potassium citrate is a particularly good countermeasure that is used on the ground. We're hoping to assess whether or not the supplement was helpful to crewmembers in reducing the renal stone risk," she said. "Also, it's a very simple procedure -- just like taking a vitamin."
But swallowing the pill can be a bit tricky in weightlessness, she noted.
"I just kind of threw it toward the back of my mouth and drank some water afterward," said Whitson. "It took a little bit to learn how to get it back there efficiently."