Linked Life Data

8526836

Source:http://linkedlifedata.com/resource/pubmed/id/8526836

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
10
pubmed:dateCreated
1996-1-24
pubmed:abstractText
This study was performed to determine the effects of 28 d of head-down tilt (HDT) (simulated weightlessness) on cardiovascular responses to orthostatic stress induced by lower body negative pressure (LBNP) (before, during, and after HDT) and +60 degrees head-up tilt (before and after HDT) in 12 subjects. Half of them underwent countermeasures (CM) of regular muscular exercise (isometric and isokinetic training) and LBNP sessions (-30 mm Hg) as generally performed during spaceflight; the other six were a control group (C). The countermeasure effect on the orthostatic responses to LBNP and tilt test was assessed by studying the changes after HDT in the two groups. Essentially, blood pressure was better maintained in group CM in the tilt test after HDT (MBP at the end of the tilt vs. baseline value: +16% (CM); -19% (C)). LBNP and muscular exercise may have contributed to this improvement. One of the probable contributing factors is the relative conservation of plasma volume, at the end of HDT, in group CM (-2.2%), compared to group C (-11.2%). Transcranial Doppler (TCD) recordings of middle cerebral artery (MCA) velocities permitted indirect evaluation of cerebral blood flow changes during the orthostatic tests. MCA velocities decreased significantly although slightly (-7 to -12%) during LBNP sessions without changes along the HDT showing that the cerebral circulation was well preserved in each group. On the other hand, subjects undergoing presyncopal symptoms presented a drop in MCA velocities, suggesting a decrease in cerebral blood flow.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0095-6562
pubmed:author
pubmed:issnType
Print
pubmed:volume
66
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
982-91
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
Effects of 28-day head-down tilt with and without countermeasures on lower body negative pressure responses.
pubmed:affiliation
MEDES, Institut de Médecine et de Physiologie Spatiales, Toulouse, France.
pubmed:publicationType
Journal Article, Clinical Trial, Controlled Clinical Trial, Research Support, Non-U.S. Gov't