| Insufficient flow reduction during LBNP in both splanchnic and lower limb areas is associated with orthostatic intolerance after bedrest. | |
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MedLine Citation:
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PMID: 18757480 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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We quantified the impact of a 60-day head-down tilt bed rest (HDBR) with countermeasures on the arterial response to supine lower body negative pressure (LBNP). Twenty-four women [8 control (Con), 8 exercise + LBNP (Ex-LBNP), and 8 nutrition (Nut) subjects] were studied during LBNP (0 to -45 mmHg) before (pre) and on HDBR day 55 (HDBR-55). Left ventricle diastolic volume (LVDV) and mass, flow velocities in the middle cerebral artery (MCA flow) and femoral artery (femoral flow), portal vein cross-sectional area (portal flow), and lower limb resistance (femoral resistance index) were measured. Muscle sympathetic nerve activity (MSNA) was measured in the fibular nerve. Subjects were identified as finishers or nonfinishers of the 10-min post-HDBR tilt test. At HDBR-55, LVDV, mass, and portal flow were decreased from pre-HDBR (P < 0.05) in the Con and Nut groups only. During LBNP at HDBR-55, femoral and portal flow decreased less, whereas leg MSNA increased similarly, compared with pre-HDBR in the Con, Nut, and NF groups; 11 of 13 nonfinishers showed smaller LBNP-induced reductions in both femoral and portal flow (less vasoconstriction), whereas 10 of 11 finishers maintained vasoconstriction in either one or both regions. The relative distribution of blood flow in the cerebral versus portal and femoral beds during LBNP [MCA flow/(femoral + portal flow)] increased or reduced < 15% from pre-HDBR in 10 of 11 finishers but decreased > 15% from pre-HDBR in 11 of 13 nonfinishers. Abnormal vasoconstriction in both the portal and femoral vascular areas was associated with orthostatic intolerance. The vascular deconditioning was partially prevented by Ex-LBNP. |
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Authors:
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P Arbeille; P Kerbeci; L Mattar; J K Shoemaker; R Hughson |
Publication Detail:
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Type: Journal Article; Randomized Controlled Trial; Research Support, Non-U.S. Gov't Date: 2008-08-29 |
Journal Detail:
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Title: American journal of physiology. Heart and circulatory physiology Volume: 295 ISSN: 0363-6135 ISO Abbreviation: Am. J. Physiol. Heart Circ. Physiol. Publication Date: 2008 Nov |
Date Detail:
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Created Date: 2008-11-10 Completed Date: 2008-12-22 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 100901228 Medline TA: Am J Physiol Heart Circ Physiol Country: United States |
Other Details:
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Languages: eng Pagination: H1846-54 Citation Subset: IM |
Affiliation:
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Unité Medecine Physiologie Spatiale, Universite Hopital Trousseau, Tours 37044, France. arbeille@med.univ-tours.fr |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Bed Rest
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adverse effects* Cardiac Output Cardiovascular Deconditioning* Cerebrovascular Circulation Dietary Proteins / administration & dosage* Exercise* Female Femoral Artery / physiopathology Head-Down Tilt / adverse effects Humans Lower Body Negative Pressure* Lower Extremity / blood supply* Middle Cerebral Artery / physiopathology Muscle, Skeletal / blood supply, innervation Orthostatic Intolerance / etiology, physiopathology, prevention & control* Portal Vein / physiopathology Regional Blood Flow Space Flight Splanchnic Circulation* Sympathetic Nervous System / physiopathology Vascular Resistance Vasoconstriction Weightlessness Countermeasures* Weightlessness Simulation / adverse effects |
| Chemical | |
Reg. No./Substance:
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0/Dietary Proteins |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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