Jean-Claude Launay

Learn More
Assessment of individual susceptibility to altitude illnesses and more particularly to acute mountain sickness (AMS) by means of tests performed in normobaric hypoxia (NH) or in hypobaric hypoxia (HH) is still debated. Eighteen subjects were submitted to HH and NH tests (PIO2=120 hPa, 30 min) before an expedition. Maximal and mean acute mountain sickness(More)
Hand cooling is a cold pressor test, which induces general sympathetic stimulation. This cooling procedure is often performed to investigate cold induced vasodilatation (CIVD) in one finger. To investigate the effects of this sympathetic stimulation on local CIVD, 12 subjects immersed either the right index finger (T1), right hand (T2) or left hand and(More)
Since Bert (1878) and Barcroft (1925), studies on hypoxia are realized by lowering ambient O2 partial pressure (PO2) either by barometric pressure reduction (hypobaric hypoxia HH) or by lowering the O2 fraction (normobaric hypoxia NH). Today, a question is still debated: "are there any physiological differences between HH and NH for the same ambient PO2?"(More)
Erythropoiesis was studied in 11 subjects submitted to a 4-h hypoxia (HH) in a hypobaric chamber (4,500 m, barometric pressure 58.9 kPa) both before and after a 3-week sojourn in the Andes. On return to sea level, increased red blood cells (+3.27%), packed cell volume (+4.76%), haemoglobin (+6.55%) (P<0.05), and increased arterial partial pressure of oxygen(More)
The effects of hydromineral hormones and catecholamines on renal water and electrolyte excretion were examined during and after dehydration induced by either passive heat or exercise. Eight healthy young Caucasian subjects participated in three separate trials, each including three consecutive phases. Phases 1 and 3 involved a 90-min period at rest in a(More)
OBJECTIVE A survival sojourn in a tropical climate exposes subjects to 2 main constraints: food restriction and tropical climatic conditions. We hypothesized that such a sojourn could modify anthropological characteristics and thermoregulatory responses to heat and cold on return. METHODS Eight European male subjects were submitted to a sweating test (ST)(More)
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(More)
Platelet aggregation can be measured quantitatively by continuous recording of the transmission of a beam of light across a suspension of platelets in constant agitation in an aggregometer. In routine clinical investigation, the study of platelet aggregation is performed on platelet-rich citrated plasma (PRPc). The blood sample has to be excellent to(More)
BACKGROUND AND PURPOSE Echolucent carotid plaques compared with echogenic plaques could carry a significant risk of transient ischemic attacks and strokes, but the reproducibility of new ultrasonic methods has not yet been proved. The objective was to evaluate interobserver and intraobserver agreement in characterizing the carotid plaques studied by both B(More)
BACKGROUND Sleep deprivation (SD) induces many adverse psychological and physiological effects, particularly on vigilance and the thermoregulatory system. The drug modafinil appears to suppress or diminish the harmful effects on vigilance. However, the effects of modafinil combined with SD on the circadian rhythm of core temperature are not well(More)