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Effects of 1-week head-down tilt bed rest on bone formation and the calcium endocrine systemThe -6-deg head-down tilt (HDT) is employed in the study of 8 subjects to determine early responses in human bone and calcium endocrines during spaceflight. The average rates of bone formation in the iliac crest are determined by means of a single-dose labeling schedule and are found to decrease in 6 of the subjects. The decrease varies directly with walking miles, and increased excretion of urinary Ca and Na are observed preceding increased levels of ionized serum calcium on a bed-rest day late in the week. Reduced phosphorous excretions are also followed by increased serum phosphorous on day six, and reductions are noted in parathyroid hormone and vitamin D by the end of the experiment. The data demonstrate the responsiveness of the skeletal system to biomechanical stimuli such as the HDT.
Document ID
19920038089
Document Type
Reprint (Version printed in journal)
Authors
Arnaud, Sara B. (NASA Ames Research Center Moffett Field, CA, United States)
Whalen, Robert T. (NASA Ames Research Center Moffett Field, CA, United States)
Fung, Paul (NASA Ames Research Center Moffett Field, CA, United States)
Sherrard, Donald J. (NASA Ames Research Center Moffett Field, CA, United States)
Maloney, Norma (Washington, University; USVA, Medical Center Seattle, United States)
Date Acquired
August 15, 2013
Publication Date
January 1, 1992
Publication Information
Publication: Aviation, Space, and Environmental Medicine
Volume: 63
ISSN: 0095-6562
Subject Category
AEROSPACE MEDICINE
Distribution Limits
Public
Copyright
Other