Guillemette Gauquelin

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The volume regulating hormones were studied during a 4-week head-down tilt (CNES HDT) in five subjects with and without (controls) lower body negative pressure (LBNP). LBNP was applied 3 times a day for 3 weeks, 4 times a day for 4 d, and 6 times a day for 3 d the last week. In both groups we observed a significant decrease in body weight (3% in controls,(More)
The aim of this study was to determine the effects of a 4-day head-down tilt (HDT; − 6°) and 4-day confinement on several indicators that might reflect a state of cardiovascular deconditioning on eight male subjects. Measurements were made of endocrine responses, heart rate variability and spontaneous baroreflex response (SBR) slope before, during and after(More)
To verify whether a long-term weightlessness simulation was associated with development of cardiovascular deconditioning, male Wistar rats were tail suspended for 13 days and then removed for a 24-h recovery. Blood pressure (BP) and heart rate (HR) responses, their spectral properties, and the pharmacologically tested baroreceptor reflex sensitivity were(More)
Cardiovascular hemodynamics were assessed by ultrasound echography and Doppler during a 28-d head-down tilt "CNES HDT: 87-88," and during the 25-d French-Soviet spaceflight "Aragatz 88." For both studies we used the same ultrasound methodology. The main hemodynamic parameters of the left heart function and of the peripheral arterial system (cerebral, renal,(More)
Orthostatic intolerance (OI) is the most serious symptom of cardiovascular deconditioning induced by head-down bed rest or weightlessness. Wearing venoconstrictive thigh cuffs is an empirical countermeasure used by Russian cosmonauts to limit the shift of fluid from the lower part of the body to the cardio-cephalic region. Our aim was to determine whether(More)
The aim of this study was to determine what effects social isolation and confinement stress had on the volume regulating hormones. In six healthy male subjects, during a 28-d isolation and confinement study (ESA-ISEMSI'90), hematocrit, blood pressure and resting heart rate, plasma cortisol, renin, aldosterone, arginine vasopressin levels besides the(More)
The concentration of atrial natriuretic factor (ANF) in atria and plasma was investigated in relation to the regulation of renal glomerular ANF receptors in the rat during changes in water and sodium intake. A decrease in plasma immunoreactive ANF (IR-ANF) was observed after 4 days of water deprivation or after 1 wk on a low-sodium diet, whereas animals(More)
The loss of appropriate cardiovascular reflexes which contributes to the cardiovascular deconditioning observed after an exposure to actual or simulated microgravity (in man or animals) is well known, but the mechanisms responsible remain unclear. This protocol, a 2.5 h hindlimb suspension in rats, was undertaken to study the early adaptation of the(More)
To determine whether exercise and Lower Body Negative Pressure (LBNP) during 28 days of -6 degrees head-down tilt (HDT) would modify orthostatic tolerance and blood volume regulating hormones, twelve healthy men were assigned to either a no- countermeasure (No-CM, n=6), or a countermeasure (CM, n=6) group. LBNP sessions consisted of 15 minutes exposure to(More)
Head-down tilt (HDT) bed rest was used in this study to achieve physiological manipulation of the plasma concentrations of atrial natriuretic peptide (ANP) and the hormones of the renin-angiotensin system. The purpose of this was to achieve a parallel with previous animal experiments in which blockade of the renin-angiotensin system caused significant(More)