Reporter Volume 25, No.7 October 14, 1993

By LOIS BAKER
News Bureau Staff

Astronauts on NASA's second Spacelab Life Sciences Mission will
continue an experiment developed by a team of UB researchers that
showed during the first mission that in the weightlessness of space,
the human body regulates the cardiovascular system in a novel manner.
	Data gathered from the second round of experiments in space
will provide cardiovascular performance information on three more
astronauts, over a longer period of time. Spacelab Life Sciences 2 is
scheduled for a 14-day flight, while the first mission in June 1991
lasted nine days. 
	The mission is scheduled for launch on Oct. 14.
	UB researchers speculate that even five more days of
weightlessness in space could cause more pronounced and longer-lasting
effects on the heart and lungs. The experiment is one of three studies
to be conducted during the mission focusing on astronauts'
cardiovascular functioning in zero gravity.
	Designed by a team of UB scientists headed by Leon E. Farhi,
distinguished professor of physiology, the project uses special
equipment designed by UB technicians to determine how the heart and
lungs perform in and adapt to a weightless environment during exercise
and at rest, and how that adaptation affects the astronauts'
readjustment to gravity.
	Earthbound research in simulated weightlessness has shown that
when gravity is eliminated, the heart pumps more blood initially, but
the body eventually adjusts to this increased output by eliminating
some blood plasma through urine, which reduces the total blood volume.
This action re-balances the cardiovascular system and keeps blood
pressure normal.
	However, results from the first mission showed that during
space flight, the cardiovascular system regained its balance by
readjusting the vascular tone, thereby maintaining blood pressure in
the face of an elevated cardiac output. 
	"This type of regulation of blood pressure was completely
unexpected," Farhi said. "The system's failure to reduce cardiac
output surprised us."
	UB scientists expect to collect more data on this phenomenon
from Spacelab Life Sciences 2. 
	Astronauts David Wolf, Shannon Lucid, and Martin Fettman have
been training for more than a year at UB and the Johnson Space Center
in Houston, learning how to conduct the experiments in the confines of
the Space Shuttle Columbia. 
	UB researchers took readings of the astronauts' cardiac
output, oxygen consumption, mean blood pressure and heart rate five
times during the six months preceding the flight, and calculated
stroke volume, resistance to blood flow exerted by the blood vessels,
and the amount of oxygen extracted from the blood. 
	Similar readings will be taken during the space flight while
the astronauts are at rest and while exercising. 
	They will be assessed again during the first seven days after
they touch down, and at 45 days post-flight. Astronauts on the first
flight did not regain normal cardiovascular balance and could not
perform the experiment's exercises fully for at least seven days.
	UB scientists involved in the project, in addition to Farhi,
are Albert J. Olszowka, David R. Pendergast, Barbara E. Shykoff, Mary
Anne Rokitka and Robert A. Klocke.