Biomedical subjects

Angélique Guinet-Lebreton

Publications and source records attributed to Angélique Guinet-Lebreton.

3 recordsLinked to original sources

PubMed2006

Acclimation to intermittent hypobaric hypoxia modifies responses to cold at sea level.

INTRODUCTION: Residence at high altitude modifies thremoregulatory responses to cold stress upon return to lower altitude. These changes are difficult to explain since several stresses related to high altitude may interact, including hypoxia, cold, solar radiation, and physical exertion. We hypothesized that adaptation to hypoxia without cold exposure would produce at least part of the observed changes. METHODS: Five men underwent acclimation to intermittent hypoxia (AIH) in a hypobaric chamber (8 h daily for 4 d, and 6 h on the last day, 4500 to 6000 m) at 24 degrees C. Cold stress responses were tested during a whole-body standard cold air test (1 degrees C, 2 h at rest at sea level) both before and after AIH. RESULTS: Increased reticulocyte counts and percentages confirmed acclimation to hypoxia after AIH. Changes in thermoregulation during the cold test included lower mean skin temperature after 60-80 min (18.8 +/- 0.7 degrees C vs. 19.4 +/- 0.7 degrees C); higher mean metabolic heat production (127 +/- 8 W x m(-2) vs. 118 +/- 6 W x m(-2)); and lower heat debt (7.7 +/- 1.3 kJ x kg(-1) vs. 10.3 +/- 1.2 kJ x kg(-1)), without significant change in rectal temperature. Time to onset for continuous shivering decreased after AIH (12 +/- 5 min vs. 21 +/- 6.3 min), and shivering activity occurred at higher mean skin but not rectal temperatures. CONCLUSION: AIH in comfortable ambient temperature leads to a normothermic-insulative-metabolic general cold adaptation. We conclude that AIH modifies the thermoregulatory responses to cold at sea level without cold exposure leading to a cross-adaptation.

Acclimatization↗

PubMed2004

PREDICTOL: a computer program to determine the thermophysiological duration limited exposures in various climatic conditions.

PREDICTOL is a PC program used to determine the thermophysiological duration limited exposures (DLE) in humans, nude or clothed, submitted to various climatic conditions (hot and cold climates) at rest or during a physical exercise. DLE are determined following different standards of the International Standardization Organization (ISO), especially ISO 7933 for hot environment and ISO-TR 11079 for cold environment. The original aspect of this program is that it can be used whatever the climatic conditions. The program presents two modes: an educational interactive mode and a scenario mode. The educational interactive mode demonstrates the thermophysiological effects, expressed as DLE, of different parameter changes (temperature, humidity, wind speed, metabolic heat production by physical exercise, clothing insulation and water vapor permeability). The scenario mode determines DLE for given various linked sequences as encountered in occupational, military or even recreational activities, each sequence being characterized by its climatic conditions, physical activities performed and by physical clothing properties. DLE given by PREDICTOL are correlated to those obtained in various controlled climatic laboratory conditions (r = 0.86; P < 0.001). PREDICTOL is written in Visual Basic 6.0. A "help menu" is provided to explain the use of the program and give information concerning the equations used to calculate both the thermal balance and DLE.

Body Temperature Regulation↗

PubMed2004

Prevention of acute mountain sickness by low positive end-expiratory pressure in field conditions.

OBJECTIVES: This study evaluates the ability of positive end-expiratory pressure (PEEP), a nonpharmacological method, to prevent the occurrence of acute mountain sickness during two ascents of Mount Blanc. METHODS: In a random order (once with PEEP and once without), PEEP was administered or not to eight subjects during two ascents of Mount Blanc. Scores for acute mountain sickness were quantified using the Lake Louise acute mountain sickness scoring system, and oxygen arterial blood saturation by pulse oxymetry (SpO2), heart rate, and systolic and diastolic blood pressures were also measured. RESULTS: The decrease in the prevalence of acute mountain sickness indicated that the PEEP system was effective, one case (12.5%) occurring among the eight participants with PEEP and six cases (75%) occurring among the eight without PEEP (P<0.01). The severity of the cases also decreased (P<0.01). Heart rate and blood pressure did not significantly vary, whereas the SpO2 tended to be higher with PEEP (P=0.07). CONCLUSIONS: This field study shows that PEEP could be an efficient method with which to prevent acute mountain sickness without adverse effects. However, the ergonomics of the PEEP system must be improved to make its use more practical in the future.

Acute Disease↗