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Bed Rest Standard Measures: Actilight (BRSMAct)
Principal Investigator
Research Area:
Species Studied
Scientific Name: Homo sapiens Species: Human

Gastrointestinal (GI) function plays a critical role in the absorption and bioavailability of orally administered drugs. Further, the GI tract plays a pivotal role in the bioavailability of nutrients. The availability of energy depends on intake, absorption, storage, and utilization. The absorption and bioavailability of ingested compounds depend on physiological factors such as GI motility, splanchnic blood flow, and pH of gastric secretions.

The residence time of a drug within the human body, described using pharmacokinetics, is governed by its absorption from the site of administration and clearance. Clearance is directly related to the dose of a drug, and inversely related to the systemic exposure of the drug. Important parameters affecting the pharmacokinetics of many drugs include blood flow (potentially affecting absorption, systemic distribution and/or clearance), and hepatic and renal function, the two primary organs of metabolism and excretion, respectively. Not surprisingly, the pharmacokinetics of many drugs is altered in patients who have hepatic dysfunction. Hepatic clearance is governed by two key physiological factors: hepatic arterial and portal vein blood flow and the liver’s intrinsic metabolizing enzyme activity.

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Bed rest
Gastrointestinal system
Glucose, breath
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Data Information
Data Availability
Archive is complete. Data sets are not publicly available but can be requested.
Data Sets+ Request data

Sleep Duration
Sleep Latency

Mission/Study Information
Mission Launch/Start Date Landing/End Date Duration
Campaign 1 08/29/2004 11/21/2004 84 days
Campaign 3 02/20/2005 04/14/2010 5 years, 1 month, 25 days

Additional Information
Managing NASA Center
Johnson Space Center (JSC)
Responsible NASA Representative
Johnson Space Center LSDA Office
Project Manager: Jessica Keune
Institutional Support
National Aeronautics and Space Administration (NASA)