ISS Science Operations Status Report for week ending July 24, 2002
The Expedition Five crew has successfully completed a manufacturing
experiment that could lead to an improved method of drug delivery in the
body.
A total of eight samples were processed last Thursday and Friday in the
Microencapsulation Electrostatic Processing (MEPS) experiment, said MEPS
Principal Investigator Dr. Dennis Morrison, with the Medical Sciences
Division at NASA’s Johnson Space Center in Houston.
"All data and the microcapsules produced during the experiment runs will be
returned on the STS-112 Space Shuttle mission," Morrison said. "The
experiment appeared to run without any anomalies. We are very anxious to
get back our samples and start analyzing them."
The first four experiment runs last Thursday studied the encapsulation
process, using different modes of mixing dissimilar fluids to create
microcapsules for two different formulations of a light-activated anticancer
drug derived from a porphyrin molecule isolated from blood, Morrison said.
To treat cancers, this drug is injected into blood vessels leading to the
tumor where it is preferentially absorbed by tumor cells and later activated
by applying near-infrared light that penetrates deep into tissues.
Superoxides released by the light then kill the tumor cells. The fifth
experiment Thursday encapsulated DNA from genetically engineered E. coli
bacteria.
Two experiment runs on Friday encapsulated a mix of two anti-cancer drugs
and tiny ferromagnetic particles that would allow doctors to trigger them
with a magnetic field to release their drugs into tumor tissues. The third
experiment Friday encapsulated the same drug mixture without trigger
particles and then a high voltage electrostatic field was used to deposit a
thin polymer coating onto the microcapsule outer membrane.
The automated MEPS experiment cures, filters, washes and harvests the
microcapsules for analysis on the ground. Experiments such as this could
eventually lead to the development of anti-tumor drugs that allow the
delivery of higher doses of chemotherapeutic drugs to specific treatment
sites, reducing the unwanted side effects experienced by cancer patients.
"The MEPS experiments in microgravity are conducted to better understand the
manufacturing process on Earth, where the gravity-induced sedimentation of
the different density components greatly confuses the understanding of what
conditions, fluid flow, temperature, etc. produce the most uniform
microcapsules with the maximum drug loading," Morrison said. "Thus, we are
not just checking out hardware, but making microcapsules for further study
and to develop large scale production techniques so that companies can make
these for various types of drug deliveries into human and veterinary
patients."
The Protein Crystal Growth Single Thermal Enclosure System (PCG-STES)
experiment completed processing one sample on Friday. Four other sample
processing cylinders remain active in this experiment to grow biological
materials for study on the ground and possible applications in medicine and
agriculture.
On Tuesday, the Station science team initiated the second of 10 planned
tests with the Solidification Using a Baffle in Sealed Ampoules (SUBSA)
experiment. The furnace failed to heat properly during the run, possibly
due to a software error that can be resolved by ground commanding. The
science team and controllers are troubleshooting today. Additional
troubleshooting may replace another experiment run planned for Thursday.
SUBSA is the first of two Expedition Five materials science experiments that
will study basic physical processes similar to those used to make
semiconductors for electronic devices and components used in jet engines.
A total of 10 samples will be processed during the Expedition.
The experiment also was monitored by a portable vibration sensor located in
the Microgravity Science Glovebox and connected to the Space Acceleration
Measurement System (SAMS), located in EXPRESS Rack 1. Flight Engineer Peggy
Whitson changed out the SAMS hard drive and battery last week to ensure that
the portable sensor operated correctly during the run. SAMS supports many
of the experiments onboard by characterizing the microgravity environment.
Also on Tuesday, Commander Valery Korzun and Whitson set up and conducted
the Pulmonary Function in Flight (PUFF) lung function test. Each PuFF
session includes five lung function tests. The focus is on measuring changes
in the evenness of gas exchange in the lungs, and on detecting changes in
respiratory muscle strength. A decrease in the evenness of gas exchange is
a hallmark of virtually every acute condition and disease of the pulmonary
system. Changes in respiratory muscle strength may result from long periods
in the absence of gravity. The results will help in maintaining crew health
during long space missions.
The crew today (Wednesday) was scheduled to conduct their weekly Crew
Interactions survey on the Human Research Facility laptop computer. The
Interactions experiment will identify and characterize important
interpersonal and cultural factors that may impact the performance of the
crew and ground support personnel during International Space Station
missions.
On Thursday, the crew is scheduled to collect background radiation readings
for the EVA Radiation Monitoring (EVARM) experiment and then transfer the
measurements to a laptop computer to be downlinked later that day.
On Friday, the crew is scheduled to participate in and videotape a session
with the Education Payload Operations experiment. For this activity, they
will use a variety of simple toys to illustrate basic principles of physics.
Crew Earth Observations photography subjects this week included: fires in
Zimbabwe, air quality in industrialized southeastern Africa, and vegetation
in the Parana River basin. The number of photo targets is expected to be
reduced for several weeks as the Station’s orbital path carries it over the
shadow-darkened winter of the Southern Hemisphere.
Other experiments under way in the Destiny laboratory module continue to
function normally.
