Linked Life Data

9156966

Source:http://linkedlifedata.com/resource/pubmed/id/9156966

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1997-5-22
pubmed:abstractText
Previous results from our laboratory demonstrate that changes in haematocrit (Hct) and haemoglobin concentration (Hb) underestimate the relative (%) change in plasma volume (PV) in seated subjects during simulation of weightlessness by water immersion. Therefore, we examined whether changes in Hct and Hb would accurately reflect the changes in PV in seven subjects during simulation of weightlessness by another model, 6 degrees head-down tilted bed rest (HDBR), for 42 days. Since we have previously observed unexpectedly high plasma levels of noradrenaline (NA) in astronauts during space flight, we also took the opportunity to measure this variable. The measurements were compared with those of the supine horizontal position before and after HDBR. During HDBR, PV measured by the Evans blue dye dilution technique decreased by 6.1 +/- 2.8% (P < 0.05) on day 2 and 9.6 +/- 2.2% (P < 0.05) on the 42nd day compared with that of the supine, horizontal position. Based on changes in Hct and Hb, PV decreased similarly by 8.3 +/- 2.8 and 10.2 +/- 3.2% (P < 0.05) respectively. There were no differences comparing the results of the two methods (P > 0.05). Forearm venous plasma NA was unchanged during the whole course of HDBR compared with that of the pre-HDBR supine position. It is concluded that changes in Hct and Hb reliably reflect the changes in PV comparing prolonged HDBR with the pre- and post-HDBR horizontal, supine position. Thus, changes in Hct and Hb might accurately reflect the change in PV during weightlessness in humans provided that the horizontal supine position is used as the ground-based reference. Furthermore, the results of this study, as well as of previous studies from space, confirm that NA release is unchanged or even increased during weightlessness.
pubmed:keyword
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0144-5979
pubmed:author
pubmed:issnType
Print
pubmed:volume
17
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
203-10
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1997
pubmed:articleTitle
Haematocrit, plasma volume and noradrenaline in humans during simulated weightlessness for 42 days.
pubmed:affiliation
Danish Aerospace Medical Centre of Research, Copenhagen, Denmark.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't