[Respiratory diseases and sleep during development].
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Child↗
Biomedical subjects
C Gaultier
Publications and source records attributed to C Gaultier.
Genetics, control of breathing, and sleep-disordered breathing: a review.
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Journal Article↗
Brain involvement in Dengue fever.
During the 1994-1995 outbreak of dengue fever in New Caledonia (1079 cases), two cases of encephalopathy were seen. Both patients suffered transient clinical (drowsiness, confusion) and electroencephalographic disturbances from which they fully recovered. Although this condition has been described in dengue infection a number of different pathological mechanisms are probably implicated.
Adolescent↗
Maturation of baseline breathing and of hypercapnic and hypoxic ventilatory responses in newborn mice.
Breathing during the first postnatal hours has not been examined in mice, the preferred mammalian species for genetic studies. We used whole body plethysmography to measure ventilation (VE), breath duration (T(TOT)), and tidal volume (VT) in mice delivered vaginally (VD) or by cesarean section (CS). In experiment 1, 101 VD and 100 CS pups aged 1, 6, 12, 24, or 48 h were exposed to 8% CO2 or 10% O2 for 90 s. In experiment 2, 31 VD pups aged 1, 12, or 24 h were exposed to 10% O2 for 5 min. Baseline breathing maturation was delayed in CS pups, but VE responses to hypercapnia and hypoxia were not significantly different between VD and CS pups [at postnatal age of 1 h (H1): 48 +/- 44 and 18 +/- 32%, respectively, in VD and CS pups combined]. The VE increase induced by hypoxia was greater at H12 (46 +/- 27%) because of T(TOT) response maturation. At all ages, hypoxic decline was ascribable mainly to a VT decrease, and posthypoxic decline was ascribable to a T(TOT) increase with apneas, suggesting different underlying neuronal mechanisms.
Animals↗
Patterns of EEG frequency, movement, heart rate, and oxygenation after isolated short apneas in infants.
Patterns of events occurring at the end of apneas have rarely been reported in infants. No previous studies have compared these patterns to those of spontaneous events during sleep. We examined 163 isolated apneas in 17 infants (47 +/- 4 wk postconceptional age) who underwent polysomnography for suspected upper airway problems. Mean apnea duration was 6.5+/-1.5 s (range, 5 to 11.5 s), 78% of apneas occurred in active sleep, and 67% of apneas were obstructive. We recorded the occurrence of body movement or augmented breath and analyzed changes in EEG frequency > or = 1 s, heart rate, and oxygen saturation value at the end of apneas and of a control ventilatory period defined as a period of breathing equal in duration to the apnea and preceding the apnea by 1 min. We found that 7.9% of apneas and 11.6% of control periods were followed by an augmented breath and that 14.1% of apneas and 0.5% of control periods were followed by a body movement. The percentages of motor events or no event differed significantly after the apneas (p = 0.008) compared with the control periods. A significant increase in EEG frequency was observed at the end of the apneas compared with the control periods (p < 0.04). EEG frequency increased after 61% of the apneas. Neither heart rate nor oxygen saturation value changed after the control periods. Heart rate decreased significantly after the apneas not followed by a motor event (p = 0.02) but not after the apneas followed by a body movement. We conclude that 1) at termination of isolated apneas in infants, a motor event was rare, whereas an EEG frequency increase was common; 2) event patterns at apnea termination differed from those at control period termination.
Electroencephalography↗
Impaired ventilatory responses to hypoxia in mice deficient in endothelin-converting-enzyme-1.
Endothelin-converting-enzyme (ECE-1) catalyzes the proteolytic activation of big endothelin-1 to mature endothelin-1. Most homozygous ECE-1-/- embryos die in utero and show severe craniofacial, enteric, and cardiac malformations precluding ventilatory function assessment. In contrast, heterozygous ECE-1+/- embryos develop normally. Their respiratory function at birth has not been studied. Taking into account previous respiratory investigations in mice with endothelin-1 gene disruption, we hypothesized that ECE-1-deficient mice may have impaired ventilatory control. We analyzed ventilatory responses to hypercapnia (8% CO(2)) and hypoxia (10% O(2)) in newborn and adult mice heterozygous for ECE-1 deficiency (ECE-1+/-) and in their wild-type littermates (ECE-1+/+). Ventilation, breath duration, and tidal volume were measured using whole-body plethysmography. Ventilatory responses to hypoxia were significantly weaker in ECE-1+/- than in ECE-1+/+ newborn mice (percentage ventilation increase: 1 +/- 25% versus 33 +/- 29%, p = 0.010). Baseline breathing variables and ventilatory responses to hypercapnia were normal in the ECE-1+/- newborn mice. No differences were observed between adult ECE-1+/- and ECE-1+/+ mice. We conclude that ECE-1 is required for normal ventilatory response to hypoxia at birth.
Animals↗
Abnormalities of the chemical control of breathing: Clinical correlates in infants and children.
Abnormalities of the chemical control of breathing may go unrecognized and lead to life-threatening events, especially during sleep. Tests to assess chemical control in vivo have not yet been standardized, and their results may be difficult to interpret. Non-invasive monitoring of gas exchange and polysomnography are essential to assess the severity of hypoventilation and the extent to which it is dependent on the state of alertness. One has to be aware that some patients may have increased vulnerability to stress, and that mild infections may trigger acute hypoventilation. To date, no pharmacological approaches have proved effective in the long-term. Therefore, the management of infants and children with abnormal chemical control of breathing includes ventilatory support during sleep and diaphragmatic pacing during wakefulness, if necessary. Further research is needed to improve our understanding of the mechanisms controlling chemosensitivity and of the developmental plasticity of chemosensitivity during infancy and childhood. Genetic influences, as well as environmental factors in utero or during early infancy, may contribute to abnormal chemical control of breathing during infancy and childhood.
Chemoreceptor Cells↗
Development of the control of breathing: implications for sleep-related breathing disorders in infants.
Abnormal development of the control of breathing has implications for the occurrence and severity of SDB during infancy. Prevention of prenatal insults such as nicotine exposure should be included in public health programs. Infants at risk for SDB or with symptoms of SDB should be investigated for peripheral and central chemoreceptor dysfunction. Peripheral chemoreceptor function can be assessed using either the hyperoxic test or the alternating breath test, and central chemoreceptor function using the rebreathing test. Optimal treatment of SDB in the developing infant is of central importance for preserving normal behavior and neurocognitive development. Oxygen supplementation and/or ventilatory support during sleep prevent uncontrolled episodes of hypoxemia, sleep fragmentation, and REM sleep reduction. Finally, alterations in homeostatic responses during development may have long-term effects on breathing during sleep in childhood and adulthood. In genetically-predisposed subjects, environmental conditions during the period of development of respiratory control mechanisms may add to the intrinsic vulnerability to SDB.
Arcuate Nucleus of Hypothalamus↗
The hyperoxic test in infants reinvestigated.
The hyperoxic test (HT) examines peripheral chemoreceptor function (PCF) by measuring the decrease in ventilation (V E) after 100% O(2) inhalation. A 30-s HT has been previously used in infants with calculation of the ventilatory response (VR) as the mean percentage change in V E during HT as compared with normoxia. However, it has been shown that during hyperoxia V E rises secondarily after the initial drop because of loss of PCF. We hypothesized that the mean V E change over a 30-s HT may underestimate the strength of PCF and may be poorly reproducible. We performed breath-by-breath analysis during 30-s HTs, calculating VR at the response time (RT) defined as the time from HT onset to the first significant HT-related change in V E. Eighteen infants (postnatal age, 21 +/- 4 d) underwent two HTs (quiet sleep, face mask attached to a pneumotachograph, and inspired and expired O(2) and CO(2) fractions measured using mass spectrometry). V E, VT, and VT/TI decreases at the RT were significantly greater than the corresponding means (-21 +/- 7 versus -15 +/- 7%, -21 +/- 8 versus -13 +/- 8%, and -22 +/- 11 versus -17 +/- 11%, respectively). Intra-individual coefficients of variation of V E, VT and VT/TI were significantly smaller when RT values were considered rather than means. We conclude that calculation of the VR to HT at RT improves assessment of PCF and enhances HT reproducibility in infants.
Breath Tests↗
[Neurological features after consumption of a variety of neo-caledonian shellfish].
A few days after a seafood meal a patient suffered ataxia and stupor. His examination revealed a confused patient with cerebellar signs and ocular disturbances (hypotropia). Blood results, cerebrospinal fluid and brain CT scan were unremarkable. The patient developed a septic shock and died 4 weeks after admission. No necropsy was performed. Questioning his family confirmed that he had eaten a shellfish meal a few hours before onset of the digestive signs. Trocas (Tectus pyramis) were definitely identified. The clinical picture strongly suggested a seafood poisoning, namely ciguatera. However, no toxicologic assay was performed. To our knowledge, this poisoning has never been reported with trocas. Nevertheless, the feeding habits of trocas would suggest similarity with ciguatera poisoning.
Adult↗
[Probable Miller Fisher syndrome during Dengue fever type 2].
A 57 year-old-man developed a left ophthalmoplegia associated with ataxia and areflexia while he had fever (39 degrees C) for two days. Dengue fever (DF) was diagnosed by definite criteria, i.e.: IgM seroconversion, positive culture from serum and positive PCR both from serum and CSF. Within one week, he fully and spontaneously recovered. To our knowledge, this neurological picture has never been reported in DF. Considering the immune-mediated nature of this condition, its pathogenesis in DF is proposed in reviewing the literature.
Antibodies, Viral↗
[Respiratory behavior].
The notion of respiratory behaviour is grounded, among other approaches, on studies of neuronal mechanisms of voluntary breathing, clinical data, conditioning experiments and respiratory sensations. The interactions between cortical centres of voluntary breathing and respiratory neurones in the brain stem are poorly understood: voluntary control operates through the direct action of corticomotor centres on respiratory motoneurones; however these cortical structures may directly act on bulbopontine centres, and therefore indirectly on respiratory motoneurones. Recordings in animals of brain stem neuronal activity, brain imaging in humans, and transcortical stimulation of the diaphragm in humans and in animal models support either one or the other hypothesis. The mutual independence of the automatic and the voluntary controls of breathing appears in patients with impaired bulbopontine automatism and operational voluntary control (Central Congenital Hypoventilation Syndrome), and in patients with the reverse impairment (locked-in syndrome). Finally, recent studies in humans and animals show that classical conditioning affects respiratory control and sensations.
Animals↗
[Respiratory tests in sleep disorders in children].
Nocturnal polysomnography is the reference tool for the exploration of sleep disorders in children. Noninvasive methods are to be preferred for children. Recording respiratory signals identifies respiratory events (episodes of apnea, hyponea) and their effect on gas exchange. Measuring esophageal pressure, the only quantitative measure of respiratory exertion, is required for the diagnosis of high-resistant upper airways syndrome. Recordings of neurophysiolgical signals can be used to analyze sleep organization and to quantify cortical awaking reactions. The most frequent indication in pediatric patients with sleep disorders is to explore suspected obstructive sleep apnea syndrome. The prevalence of this syndrome in the general pediatric population would be 1.6%, increasing to 8.4% in members of a family with a child having obstructive sleep apnea syndrome.
Adolescent↗
[Stabilized epilepsy in three adult cases of pachygyria].
In complex malformations of the neocortex due to neuronal migration disorders, epilepsy is usually intractable and is observed in childhood. The study of such malformations in adults is rare. Three adult cases are described with easily treated epilepsy controlled by one or two anti-epilectic drugs. A brain CAT-scan of these three patients showed pachygyria (macrogyria) sometimes associated with other malformations and disorders of neurone migration. These three 28, 40 and 53 year-old-patients (one woman and two men) were mentally disturbed with complex neurological disturbances and confined to a wheelchair. Their epilepsy had began in childhood and stabilised as these patients became adults. We raised the question as to whether this is in fact the long-term outcome for epileptic patients with pachygyria. The outcome of such epilepsy due to pachygyria could be better than initially supposed.
Adult↗
Behavioural correlates of conditioned ventilatory responses to hypoxia in rats.
To examine the possible contribution of behavioural arousal to ventilatory conditioning, we performed a differential conditioning experiment using two odours as the paired conditioned stimulus (CS + ) and unpaired conditioned stimulus (CS-) and a hypoxic mixture (7.5% O2) as the unconditioned stimulus (US) in 24 adult male rats. Vanillin was the CS + and rose the CS - in half the rats, and vice versa in the other half. Each rat underwent 26 paired CS + /hypoxia trials and 26 CS - trials in alternation, followed by two CS + only and two CS - trials to test for conditioning. Analysis of breathing variables and behavioural scores during the test showed two qualitatively different conditioned responses. The initial conditioned response was characterised by short breath durations (TT), frequent sniffing episodes, and arousal responses. Following this, a specific, conditioned increase in tidal volume (VT) and levelling off of sniffing and motor activities occurred. The early TT-response and late VT-response to CS + both contributed to an increase in ventilation (VI). The present data show that the association of an odour and hypoxia elicits a biphasic ventilatory conditioned response, of which the first component is integrated into conditioned arousal.
Animals↗
[Congenital central alveolar hypoventilation syndrome, so-called "Ondine syndrome": an orphan disease, a disease of hope].
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Child↗
Heart rate modifications related to spontaneous body movements in sleeping premature and full-term newborns.
Heart rate (HR) acceleration is an essential mechanism for adaptation to changes in hemodynamic and energetic needs resulting from body movements. To evaluate age-related development of coupling between spontaneous movement and HR changes, we performed polysomnographic recordings in 20 clinically and neurologically normal newborns including 10 premature (31- to 36-wk gestational age, wGA) and 10 full-term (38- to 41-wk gestational age) infants. Recordings were sampled at 286 Hz and processed using a signal-to-noise ratio algorithm for QRS complex detection. Movements were automatically detected and the logical signal obtained was sampled at QRS fiducial points and written in the attributes of each QRS. The study included the 402 movements that were less than 30 s in duration and were neither preceded nor followed by another movement or by a respiratory event (pause, sigh). The amplitude of movement-induced HR acceleration was significantly lower in premature compared with full-term newborns (p < 0.01). This difference persisted when the other factors influencing the HR response (basal HR, movement duration, and amplitude) were taken into consideration. Our data identify HR acceleration induced by spontaneous body movements as a fundamental reflex response that develops with gestational age from premature to full-term newborns.
Algorithms↗
Ventilatory responses to hypercapnia and hypoxia in Mash-1 heterozygous newborn and adult mice.
Normal control of breathing is characterized by maintenance of CO2 and O2 arterial pressures at constant levels by appropriate ventilatory responses to changes in CO2 production and O2 consumption. Abnormal development of this regulatory system during embryogenesis may produce early impairments in chemosensitivity, as in congenital central hypoventilation syndrome. The present study addresses the role of the mammalian achaetescute homologous gene (Mash-1) in the development of respiratory control. We analyzed ventilatory responses to hypercapnia (8% CO2, 21% O2, 71% N2) and hypoxia (10% O2, 3% CO2, 87% N2) in newborn and adult Mash-1 heterozygous mice (Mash-1+/-) and their wild-type littermates (Mash-1+/+). Ventilation, breath duration, and tidal volume were measured using whole-body plethysmography. Ventilatory responses to hypercapnia were significantly weaker in newborn male Mash-1+/- compared with Mash-1+/+ mice as a result of a weaker breath-duration response. No differences were observed between adult Mash-1+/- and Mash-1+/+ mice. Our data suggest that Mash-1 may be involved in respiratory control development via mechanisms linked to the X chromosome.
Animals↗