Cécile A Julien

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RATIONALE Intermittent hypoxia, a hallmark of sleep apnea, is a major factor for hypertension and impaired vasoreactivity. OBJECTIVES To examine the temporal occurrence of these two outcomes in order to provide insight into mechanisms and early cardiovascular disease identification. METHODS Functional and structural cardiovascular alterations were(More)
This study assessed the early vascular reactivity changes in mice after exposure to 14 days intermittent hypoxia (IH) with active or inactive sympathetic nervous system (SNS). Hindquarters of mice exposed to 14 days of IH, sham exposed mice or unhandled mice were perfused at constant flow with Krebs-Albumin (5%). Changes in perfusion pressure were assessed(More)
Ventilatory long-term facilitation (LTF; defined as gradual increase of minute ventilation following repeated hypoxic exposures) is well described in adult mammals and is hypothesized to be a protective mechanism against apnea. In newborns, LTF is absent during the first postnatal days, but its precise developmental pattern is unknown. Accordingly, this(More)
In human neonates, caffeine therapy for apnoea of prematurity, especially when associated with hypoxemia, is maintained for several weeks after birth. In the present study, we used newborn rats and whole-body plethysmography to test whether chronic exposure to neonatal caffeine treatment (NCT), alone or combined with neonatal intermittent hypoxia (n-IH)(More)
The mechanisms underlying the therapeutic function of caffeine on apneas in preterm neonates are not well determined. To better understand these effects, we exposed rat pups from postnatal d 3-12 to chronic intermittent hypoxia (5% O2/100 s every 10 min; 6 cycles/h followed by 1 h at 21% O2, 24 h/d), a model mimicking hypoxemic exposure in apneic neonates.(More)
UNLABELLED Sustained hyperventilation has a time-limited effect on cerebrovascular dynamics. We investigated whether this effect was similar among brain regions by measuring regional cerebral blood volume (CBV) with steady-state susceptibility contrast magnetic resonance imaging during 3 h of hyperventilation. Regional CBV was determined in nine(More)
Baroreflex is involved in the regulation of arterial blood pressure (BP). An increase in BP activates vagal inhibitory pathways to decrease heart rate; a concomitant decrease in sympathetic discharge reduces vascular resistance. Both responses reduce BP towards normal value. Conversely, a decrease in BP produces opposite effects to increase heart rate and(More)
The effect of progesterone as a respiratory stimulant in newborn subjects is less known than that in adults. This study investigated the dose-response curve (0, 2, 4, and 8 mg/kg, ip) of progesterone on ventilation in non-anesthetized newborn rats at 4- and 12-days old using plethysmography. Progesterone had no effects in the regulation of normoxic(More)